Ocular Hypertension: General Characteristics and Estimated Cerebrospinal Fluid Pressure. The Beijing Eye Study 2011

Purpose

To examine characteristics of ocular hypertensive subjects and potential associations with estimated cerebrospinal fluid pressure (estCSFP).

Methods

The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years. Ocular hypertension was defined as intraocular pressure (IOP) >21 mmHg, normal optic nerve head appearance and normal retinal nerve fiber layer thickness. IOP was corrected for its dependence on central corneal thickness (CCT) and corneal curvature radius. Estimated CSFP was calculated as CSFP [mmHg] = 0.44×Body Mass Index [kg/m²]+0.16×Diastolic Blood Pressure [mmHg]−0.18×Age [Years]−1.91. Estimated trans-lamina cribrosa pressure difference (estTLCPD) was IOP–estCSFP.

Results

EstCSFP (10.5±3.6 mmHg versus 9.0±3.7 mmHg; P = 0.003) and estTLCPD (12.0±4.4 mmHg versus 5.4±3.8 mmHg; P<0.001) were higher in the ocular hypertensive group than in the normotensive group. In binary regression analysis, ocular hypertension was associated with increased estCSFP (P = 0.03; odds ratio (OR): 1.08; 95% confidence interval (CI): 1.01, 1.17) after adjusting for prevalence of arterial hypertension (P = 0.07; OR: 1.79; 95%CI: 0.96, 3.34), retinal nerve fiber layer thickness (P = 0.03; OR: 0.97; 95%CI: 0.95, 0.997) and blood glucose concentration (P = 0.006; OR: 1.17; 95%CI: 1.04, 1.30).

Conclusions

Ocular hypertensive subjects (with IOP correction for CCT and corneal curvature) as compared to ocular normotensive subjects had a significantly higher estCSFP in univariate analysis and in multivariate analysis. Despite of a higher estCSFP, estTLCPD was still markedly higher in ocular hypertensive eyes than in ocular normotensive eyes.     

Effect Modifying Role of Serum Calcium on Mortality-Predictability of PTH and Alkaline Phosphatase in Hemodialysis Patients: An Investigation Using Data from the Taiwan Renal Registry Data System from 2005 to 2012

Predicting mortality in dialysis patients based on low intact parathyroid hormone levels is difficult, because aluminum intoxication, malnutrition, older age, race, diabetes, or peritoneal dialysis may influence these levels. We investigated the clinical implications of low parathyroid hormone levels in relation to the mortality of dialysis patients using sensitive, stratified, and adjusted models and a nationwide dialysis database. We analyzed data from 2005 to 2012 that were held on the Taiwan Renal Registry Data System, and 94,983 hemodialysis patients with valid data regarding their intact parathyroid levels were included in this study. The patient cohort was subdivided based on the intact parathyroid hormone and alkaline phosphatase levels. The mean hemodialysis duration within this cohort was 3.5 years. The mean (standard deviation) age was 62 (14) years. After adjusting for age, sex, diabetes, the hemodialysis duration, serum albumin levels, hematocrit levels, calcium levels, phosphate levels, and the hemodialysis treatment adequacy score, the single-pool Kt/V, the crude and adjusted all-cause mortality rates increased when alkaline phosphatase levels were higher or intact parathyroid hormone levels were lower. In general, at any given level of serum calcium or phosphate, patients with low intact parathyroid hormone levels had higher mortality rates than those with normal or high iPTH levels. At a given alkaline phosphatase level, the hazard ratio for all-cause mortality was 1.33 (p < 0.01, 95% confidence interval 1.27–1.39) in the group with intact parathyroid hormone levels < 150 pg/mL and serum calcium levels > 9.5 mg/dL, but in the group with intact parathyroid hormone levels > 300 pg/mL and serum calcium levels > 9.5 mg/dL, the hazard ratio was 0.92 (95% confidence interval 0.85–1.01). Hence, maintaining albumin-corrected high serum calcium levels at > 9.5 mg/dL may correlate with poor prognoses for patients with low intact parathyroid hormone levels.     

Glycaemic threshold for changes in electroencephalograms during hypoglycaemia in patients with insulin dependent diabetes

The relation between blood glucose concentration, the symptoms and signs of hypoglycaemia, and electroencephalographic changes in diabetic patients is not known. The effect of hypoglycaemia on brain function was studied in 13 patients with insulin dependent diabetes. During a gradual fall in blood glucose concentration induced by a bolus injection of insulin followed by an intravenous infusion of insulin, during 60 minutes of biochemical hypoglycaemia, and after restoration of normoglycaemia with intravenous glucose electroencephalograms were evaluated continuously by period-amplitude analysis; blood samples were taken every 10 minutes throughout. No changes were seen in electroencephalograms when the blood glucose concentration was above 3 mmol/l. At a median blood glucose concentration of 2·0 (95% confidence interval 1·7 to 2·3) mmol/l alpha activity decreased abruptly in the electroencephalograms concomitant with an increase in theta activity, reflecting neuronal dysfunction in the cortex. When the blood glucose concentration was further lowered changes were observed in the electroencephalograms indicating that deeper brain structures were affected. A normal electroencephalogram was re-established at a blood glucose concentration of 2·0 (1·8 to 2·1) mmol/l. There was no significant correlation between the blood glucose concentration at the onset of changes in the electroencephalograms and age, duration of diabetes, insulin dose, haemoglobin A_1c concentration, initial blood glucose concentration, rate of fall in blood glucose concentration, and appearance of symptoms and signs of hypoglycaemia.Changes in electroencephalograms during hypoglycaemia appear and disappear at such a narrow range of blood glucose concentrations that the term threshold blood glucose concentration for the onset of such changes seems justified.     

Insulin resistance in offspring of hypertensive parents.

OBJECTIVE--To determine if insulin resistance is present in normotensive adults at increased risk of developing hypertension. DESIGN--Normotensive subjects with at least one hypertensive parent were paired with offspring of normotensive parents (controls), being matched for age, sex, social class, and physical activity. SETTING--Outpatient clinic. SUBJECTS--30 paired subjects (16 men and 14 women) with and without a family history of hypertension, aged 18-32, with a body mass index < 25 kg/m2, with blood pressure < 130/85 mm Hg, and not taking drugs. INTERVENTIONS--Euglycaemic glucose clamp (two hour infusion of insulin 1 mU/kg/min) and intravenous glucose tolerance test (injection of 100 ml 20% glucose). MAIN OUTCOME MEASURES--Insulin mediated glucose disposal and insulin secretion. RESULTS--The offspring of hypertensive parents had slightly higher blood pressure than did the controls (mean 117 (SD 6) v 108 (5) mm Hg systolic, p = 0.013; 76 (7) v 67 (6) mm Hg diastolic, p = 0.017). Their insulin mediated glucose disposal was lower than that of controls (29.5 (6.5) v 40.1 (8.6) mumol/kg/min, p = 0.002), but, after adjustment for blood pressure, the difference was not significant (difference 6.9 (95% confidence interval -1.5 to 15.3), p = 0.10). Insulin secretion in the first hour after injection of glucose was slightly but not significantly higher in the offspring of hypertensive patients (9320 (5484) v 6723 (3751) pmol.min/l). The two groups had similar concentrations of plasma glucose (5.2 (0.3) v 5.1 (0.4) mmol/l), serum cholesterol (4.4 (0.8) v 4.6 (0.8) mmol/l), serum triglyceride (0.89 (0.52) v 0.68 (0.27) mmol/l), and serum low density lipoprotein cholesterol (2.81 (0.65) v 2.79 (0.61) mmol/l). The offspring of hypertensive parents, however, had lower serum concentrations of high density lipoprotein cholesterol (1.24 (0.31) v 1.56 (0.35) mmol/l, p = 0.002) and higher serum concentrations of non-esterified fatty acids (0.7 (0.4) v 0.4 (0.4) mmol/l, p = 0.039). CONCLUSIONS--Young normotensive subjects who are at increased risk of developing hypertension are insulin resistant.     

Impaired renal functional reserve and albuminuria in essential hypertension

The stimulatory effects of an infusion of amino acids on glomerular filtration rate has previously been used to measure renal functional reserve and detect glomerular hyperfiltration. Thirty four patients with mild to moderate essential hypertension and seemingly normal renal function and 22 healthy controls were given infusions of amino acids to investigate whether renal functional reserve is reduced in essential hypertension and to detect patients at risk of renal damage. Although basal creatinine clearance increased after the infusion of amino acids in the controls (mean 27·9 ml/min; 95% confidence interval 18·2 to 37·6), the overall change was lower in the patients (mean 13·4 ml/min; 8·3 to 18·5), 11 of the 34 showing no increase at all. In these 11 non-responders the mean systolic blood pressure was higher than that in the 23 others (178·5 mm Hg v 157 mm Hg, respectively). Mean urinary albumin excretion was abnormal in the patients (93·3 mg/24 h; 44·2 to 142·4); eight of the 11 non-responders had an albumin excretion above the normal range (>20 mg/24 h). In the 11 patients without renal functional reserve a positive correlation was found between basal creatinine clearance and albumin excretion (r=0·695).As consumed renal reserve and albuminuria are markers of glomerular hyperfiltration studying renal function before and after infusion of amino acids can detect hypertensive patients at risk of progressive renal damage.     

Interpretation of Serum Calcium in Patients with Abnormal Serum Proteins

Two hundred consecutive specimens received in this laboratory for “liver function tests” showed a wide range of abnormal protein concentrations. Calcium concentration correlated closely with albumin (r = 0·867) but less closely with total protein (r = 0·682). A simple formula for adjusting calcium concentration was derived from the regression equation of calcium on albumin. Adjusted calcium = calcium - albumin + 4·0, where calcium is in mg/100 ml and albumin in g/100 ml.Low calcium concentrations were found in 49 (24·5%) and raised concentrations in six (3%) of the 200 blood specimens taken for liver function tests. After adjustment, the 95% limits of the observed range were identical with the 95% limits of the normal range determined in this laboratory. Unlike adjustments based on total protein or specific gravity, the adjustment on albumin in 39 specimens which showed hypergammaglobulinaemia on electrophoresis gave normal calcium concentrations.     

Impaired aerobic work capacity in insulin dependent diabetics with increased urinary albumin excretion

To assess whether decreased aerobic work capacity was associated with albuminuria in insulin dependent diabetics aerobic capacity was measured in three groups of 10 patients matched for age, sex, duration of diabetes, and degree of physical activity. Group 1 comprised 10 patients with normal urinary albumin excretion (<30 mg/24 h), group 2 comprised 10 with incipient diabetic nephropathy (urinary albumin excretion 30-300 mg/24 h, and group 3 comprised 10 with clinical diabetic nephropathy (urinary albumin excretion >300 mg/24 h). Ten non-diabetic subjects matched for sex, age, and physical activity served as controls. Oxygen uptake was similar in the four groups at rest and during a 75 W workload. Maximal oxygen uptake was also similar in the control subjects and group 1 (median 41·7, (range 29·1-53·0) ml/kg/min v 38·5 (26·6-59·2) ml/kg/min, respectively), but was significantly lower in group 2 (27·7 (13·9-44·3) ml/kg/min) and group 3 (26·8 (22·6-36·7) ml/kg/min). The difference in maximal oxygen uptake between groups 1 and 2 was 10·8 ml/kg/min (95% confidence interval 3·6 to 23·4 ml/kg/min) and between groups 1 and 3, 11·7 ml/kg/min (4·9 to 22·5 ml/kg/min). These differences were not explained by differences in metabolic control or the degree of autonomic neuropathy.Thus the insulin dependent diabetics with only slightly increased urinary albumin excretion had an appreciably impaired aerobic work capacity which could not be explained by autonomic neuropathy or the duration of diabetes. Whether the reduced capacity is due to widespread microangiopathy or another pathological process affecting the myocardium remains to be established.     

British Regional Heart Study: geographic variations in cardiovascular mortality,and the role of water quality

In a study of regional variations in cardiovascular mortality in Great Britain during 1969-73 based on 253 towns the possible contributions of drinking water quality, climate, air pollution, blood groups, and socioeconomic factors were evaluated. A twofold range in mortality from stroke and ischaemic heart disease was apparent, the highest mortality being in the west of Scotland and the lowest in south-east England. A multifactorial approach identified five principal factors that substantially explained this geographic variation in cardiovascular mortality—namely, water hardness, rainfall, temperature, and two social factors (percentage of manual workers and car ownership). After adjustment for other factors cardiovascular mortality in areas with very soft water, around 0·25 mmol/l (calcium carbonate equivalent 25 mg/l), was estimated to be 10-15% higher than that in areas with medium-hard water, around 1·7 mmol/l (170 mg/l), while any further increase in hardness beyond 1·7 mmol/l did not additionally lower cardiovascular mortality.Thus a negative relation existed between water hardness and cardiovascular mortality, although climate and socioeconomic conditions also appeared to be important influences. Cross-sectional and prospective surveys of 7500 middle-aged men from 24 towns are in progress and will permit further exploration of these geographic differences, especially with regard to personal risk factors such as blood pressure, blood lipid concentrations, and cigarette smoking.     

Advice to use topical or oral ibuprofen for chronic knee pain in older people: randomised controlled trial and patient preference study

Objective To determine whether older patients with chronic knee pain should be advised to use topical or oral non-steroidal anti-inflammatory drugs (NSAIDs).Design Randomised controlled trial and patient preference study.Setting 26 general practices.Participants People aged ≥50 with knee pain: 282 in randomised trial and 303 in preference study. Interventions Advice to use topical or oral ibuprofen.Primary outcome measures WOMAC (Western Ontario and McMaster Universities) osteoarthritis index, major and minor adverse effects.Results Changes in global WOMAC scores at 12 months were equivalent. In the randomised trial the difference (topical minus oral) was two points (95% confidence interval −2 to 6); in the preference study, it was one point (−4 to 6). There were no differences in major adverse effects in the trial or study. The only significant differences in secondary outcomes were in the randomised trial. The oral group had more respiratory adverse effects (17% v 7%,95% confidence interval for difference −17% to −2%), the change in serum creatinine was 3.7 mmol/l less favourable (0.9 µmol/l to 6.5 µmol/l); and more participants changed treatments because of adverse effects (16% v 1%, −16% to −5%). In the topical group more participants had chronic pain grade III or IV at three months, and more participants changed treatment because of ineffectiveness.Conclusions Advice to use oral or topical preparations has an equivalent effect on knee pain over one year, and there are more minor side effects with oral NSAIDs. Topical NSAIDs may be a useful alternative to oral NSAIDs.Trial registration ISRCTN 79353052.     

Factors protective against retinopathy in insulin-dependent diabetics free of retinopathy for 30 years

To investigate which factors might protect against the development of retinopathy 40 insulin-dependent diabetics who had remained free from retinopathy despite diabetes of long duration (mean±1 SD 30±10 years) were compared with 40 patients who had background and 47 who had proliferative retinopathy (mean durations of disease 16±5 and 19±5 years respectively). The three groups had had similar mean ages at onset of diabetes. The mean of all postprandial blood glucose measurements at hospital clinics from diagnosis of diabetes to detection of retinopathy, or to the most recent negative eye examination, was 9·9±2·1 mmol/l (178±38 mg/100 ml) in the group with no retinopathy, 11·8±2·1 mmol/l (213±38 mg/100 ml) in those with background retinopathy, and 12·4±2·1 mmol/l (223±38 mg/100 ml) in those with proliferative retinopathy (p <0·0001). This difference was not reflected in present concentrations of haemoglobin A_1C, probably because glycaemic control had been improved after the development of retinopathy. In the groups with background and proliferative retinopathy there were significant negative correlations between mean blood glucose concentrations and the number of years that had elapsed from diagnosis of diabetes to detection of retinopathy, suggesting that the development of both grades of retinopathy depends on the degree and duration of glycaemic exposure.The patients with no retinopathy had attended clinic more frequently (p <0·025), more of them had required emergency hospital treatment for hypoglycaemia (p <0·0025), and they tended to have had a lower prevalence of hyperglycaemic coma than the other groups. Although mean percentage ideal body weight and diastolic blood pressure were lower in the patients with no retinopathy at the time of study, mean body weight, blood pressure, and the prevalence of smoking in the years before the development of retinopathy had been similar in all groups, suggesting that these did not influence the development of retinopathy.     

Kidney stones and hypertension: population based study of an independent clinical association.

OBJECTIVE--To test the hypothesis that kidney stone disease is more frequent among hypertensive men when the effect of possible confounders is allowed for. DESIGN--Cross sectional study of a sample of the male working population conducted as part of the 10 year follow up of a nationwide survey of the prevalence of cardiovascular risk factors. SETTING--The Olivetti factory in Pozzuoli, a suburban area of Naples. POPULATION--688 Male workers (87.9% of the male workforce) aged 21-68. INTERVENTIONS--Anthropometric and blood pressure measurements, blood tests, and administration of a detailed questionnaire aimed at detecting a history of urolithiasis. MAIN OUTCOME MEASURES--Prevalence of a history of urolithiasis among normotensive and untreated and treated hypertensive men adjusted for the possible confounding effects of age, body mass index, renal function, and serum urate and total calcium concentrations. RESULTS--Of the 688 participants 509 were normotensive. Of the remainder, 118 had untreated and 61 treated hypertension. The overall prevalence of a history of urolithiasis was 16.3% (112/688). The relative risk of hypertensive subjects having a history of kidney stones was twice that of the normotensive group (odds ratio 2.11; 95% confidence interval 1.17 to 3.81), the risk being higher when only treated hypertensives were considered (odds ratio 3.16; 95% confidence interval 1.75 to 5.71). The prevalence of a history of urolithiasis was 13.4% (68/509) in the normotensive subjects, 20.3% (24/118) in the untreated hypertensives, and 32.8% (20/61) in the treated hypertensives (p less than 0.001). The age adjusted relative risk in treated hypertensive men was higher than that in the normotensive group (Mantel-Haenszel pooled estimate of odds ratio 2.63; 95% confidence interval 2.23 to 3.10). CONCLUSION--An independent clinical association exists between the occurrence of urolithiasis and hypertension. The increased urinary calcium excretion commonly detected in hypertension may be the pathogenetic link.     

Radioimmunoassay of Parathyroid Hormone in Primary Hyperparathyroidism: Studies after Removal of Parathyroid Adenoma

Parathyroid hormone has been measured by radioimmunoassay in eight patients with hyperparathyroidism due to parathyroid adenoma. Secretion of hormone by the adenomatas was demonstrated direct by estimating the arteriovenous gradient of parathyroid hormone across the tumours. Serial estimations following surgical removal of the adenoma showed a rapid fall in the concentration of circulating parathyroid hormone. The calculated half-life of endogenously secreted parathyroid hormone in man varied from 11·4 to 28·8 min., with a mean of 19·8 min.     

Effects of High Intensity Interval Training and Strength Training on Metabolic,Cardiovascular and Hormonal Outcomes in Women with Polycystic Ovary Syndrome: A Pilot Study

Background

Polycystic ovary syndrome is a common endocrinopathy in reproductive-age women, and associates with insulin resistance. Exercise is advocated in this disorder, but little knowledge exists on the optimal exercise regimes. We assessed the effects of high intensity interval training and strength training on metabolic, cardiovascular, and hormonal outcomes in women with polycystic ovary syndrome.

Materials and Methods

Three-arm parallel randomized controlled trial. Thirty-one women with polycystic ovary syndrome (age 27.2 ± 5.5 years; body mass index 26.7 ± 6.0 kg/m²) were randomly assigned to high intensity interval training, strength training, or a control group. The exercise groups exercised three times weekly for 10 weeks.

Results

The main outcome measure was change in homeostatic assessment of insulin resistance (HOMA-IR). HOMA-IR improved significantly only after high intensity interval training, by -0.83 (95% confidence interval [CI], -1.45, -0.20), equal to 17%, with between-group difference (p = 0.014). After high intensity interval training, high-density lipoprotein cholesterol increased by 0.2 (95% CI, 0.02, 0.5) mmol/L, with between group difference (p = 0.04). Endothelial function, measured as flow-mediated dilatation of the brachial artery, increased significantly after high intensity interval training, by 2.0 (95% CI, 0.1, 4.0) %, between-group difference (p = 0.08). Fat percentage decreased significantly after both exercise regimes, without changes in body weight. After strength training, anti-Müllarian hormone was significantly reduced, by -14.8 (95% CI, -21.2, -8.4) pmol/L, between-group difference (p = 0.04). There were no significant changes in high-sensitivity C-reactive protein, adiponectin or leptin in any group.

Conclusions

High intensity interval training for ten weeks improved insulin resistance, without weight loss, in women with polycystic ovary syndrome. Body composition improved significantly after both strength training and high intensity interval training. This pilot study indicates that exercise training can improve the cardiometabolic profile in polycystic ovary syndrome in the absence of weight loss.

Trial Registration

ClinicalTrial.gov NCT01919281     

Long term management of duodenal ulcer in general practice: How best to use cimetidine?

Two hundred and sixty seven patients with duodenal ulceration were entered into a five year study of two strategies of treatment with cimetidine. Two thirds were treated continuously with 400 mg at bedtime supplemented by temporary increases in dosage if they had symptomatic relapses (group 1), and the remaining third were given intermittent “healing” doses for four to eight weeks if a symptomatic recurrence was judged to have occurred (group 2). Life table analysis showed that the probability of remaining free of clinically important symptoms five years after the start of treatment was 24% (95% confidence interval (CI) 15·5% to 32·6%) in group 1 compared with nil in group 2 (p<0·0001). The median values for the longest periods free from relapse for each patient were 108 weeks in group 1 and 32 weeks in group 2, respectively (p<0·0001; 95% CI of the median difference 36 to 76). Over the five years 10 patients suffered major complications, two requiring emergency surgery, while a further nine had elective surgery because of the failure of medical treatment. There were no deaths that could be attributed either to ulceration or to treatment with cimetidine.Medical management was therefore very satisfactory for most patients, though those treated continuously with cimetidine suffered considerably less from their ulcer symptoms. As 80% of patients studied relapsed during the two years after a healing course of cimetidine, continuous treatment will benefit many patients treated in general practice.     

Effect of Turbulent-Flow Pasteurization on Survival of Mycobacterium avium subsp. paratuberculosis Added to Raw Milk

A pilot-scale pasteurizer operating under validated turbulent flow (Reynolds number, 11,050) was used to study the heat sensitivity of Mycobacterium avium subsp. paratuberculosis added to raw milk. The ATCC 19698 type strain, ATCC 43015 (Linda, human isolate), and three bovine isolates were heated in raw whole milk for 15 s at 63, 66, 69, and 72°C in duplicate trials. No strains survived at 72°C for 15 s; and only one strain survived at 69°C. Means of pooled D values (decimal reduction times) at 63 and 66°C were 15.0 ± 2.8 s (95% confidence interval) and 5.9 ± 0.7 s (95% confidence interval), respectively. The mean extrapolated D_72°C was <2.03 s. This was equivalent to a >7 log₁₀ kill at 72°C for 15 s (95% confidence interval). The mean Z value (degrees required for the decimal reduction time to traverse one log cycle) was 8.6°C. These five strains showed similar survival whether recovery was on Herrold's egg yolk medium containing mycobactin or by a radiometric culture method (BACTEC). Milk was inoculated with fresh fecal material from a high-level fecal shedder with clinical Johne's disease. After heating at 72°C for 15 s, the minimum M. avium subsp. paratuberculosis kill was >4 log₁₀. Properly maintained and operated equipment should ensure the absence of viable M. avium subsp. paratuberculosis in retail milk and other pasteurized dairy products. An additional safeguard is the widespread commercial practice of pasteurizing 1.5 to 2° above 72°C.     

Growth hormone,prolactin, and corticosteroid responses to insulin hypoglycaemia in alcoholics

Plasma growth hormone (GH), prolactin, and corticosteroid responses to insulin-induced hypoglycaemia were studied in 24 men with progressive alcoholism who had been abstinent for two to seven days. Ten normal healthy subjects (five men, five women) served as controls for comparing GH and prolactin responses, while cortisol responses were studied in a further six male controls. Blood samples were taken at intervals after an injection of soluble insulin (0·1 U/kg body weight). All patients developed adequate hypoglycaemia (blood glucose <2·2 mmol/l (<39·6 mg/100 ml)) and nine had impaired GH responses (peak concentration <10 mU/1). Prolactin concentrations fell or remained unchanged in nine patients, eight of whom also had impaired GH responses. In seven patients corticosteroid concentrations decreased from basal concentrations, and six of these patients had impaired GH responses. All three hormone responses were impaired in several patients, and significant correlations were found between the GH and prolactin responses at 45 and 60 minutes. GH response was not correlated with age, duration of drinking, duration of alcoholism, or admitted alcohol intake. GH responses were significantly lower in patients who had the most severe withdrawal symptoms. Our observations of impaired stress responses in some recently abstinent alcoholics may have important implications for the management of alcohol withdrawal syndrome.     

Antibody that blocks stimulation of cortisol secretion by adrenocorticotrophic hormone in Addison's disease

To investigate whether Addison''s disease may in some cases be due to the blocking of adrenocorticotrophic hormone''s action at the adrenal cortex by antibodies IgG isolated from a woman with Addison''s disease associated with the autoimmune polyglandular syndrome type I was studied. Its effects on guinea pig adrenal cells in vitro were investigated and compared with those of IgG from three normal subjects and IgG obtained commercially. IgG from the patient inhibited the stimulation of cortisol secretion by adrenocorticotrophic hormone by 77 (SD 2)% and 57 (12)% at concentrations of 0·5 and 0·05 g/l, respectively; IgG prepared five months after she had started treatment with replacement steroids inhibited cortisol secretion by 74 (1)% (0·5 g/l) and 51 (15)% (0·05 g/l). The other IgGs had no inhibitory effects. The IgG from the patient and that obtained commercially did not inhibit the stimulation of cortisol secretion by dibutyryl cyclic adenosine monophosphate or precursors of cortisol. None of the IgGs bound to adrenocorticotrophic hormone.These results suggest that the IgG from the patient acted against the receptor for adrenocorticotrophic hormone, and its presence may explain the patient''s raised concentrations of adrenocorticotrophic hormone, failure to respond to exogenous adrenocorticotrophic hormone, and normal basal cortisol concentrations. Addison''s disease may thus in some instances be a receptor antibody disease.     

Mechanisms of hypophosphatemia in humans with heatstroke

Hypophosphatemia is common in heatstroke, but little is known about its mechanism. We investigated 10 consecutive patients with heatstroke (mean age 58 +/- 2 yr) whose mean rectal temperature at admission was 42.3 +/- 0.2 degrees C. Eight patients presented with hypophosphatemia [0.48 +/- 0.08 mmol/l, normal range (NR) 0.8-1.4 mmol/l], associated with increased fractional excretion of phosphate (19.8 +/- 6.4%, NR 6-20%) relative to plasma phosphate levels and reduced renal threshold for phosphate (0.55 +/- 0.08 mmol/l glomerular filtrate, NR 0.8-1.4 mmol/l). Plasma parathyroid hormone (75.0 +/- 5 pmol/l) and calcium (2.24 +/- 0.02 mmol/l) levels and fractional excretion of calcium were normal (1.66 +/- 0.27%). There was no evidence of uricosuria or aminoaciduria, and only one patient had glucosuria. Arterial carbon dioxide was decreased in eight patients (28 +/- 1.1 Torr); however, none had elevated blood pH (7.35 +/- 0.02). The results suggest that heatstroke-related hypophosphatemia is associated with abnormal phosphaturia independent of the parathyroid hormone level, and there is no evidence of tubular dysfunction.     

Effects of the calcium-sensing receptor A986S polymorphism on serum calcium and parathyroid hormone levels in healthy individuals: a meta-analysis

The calcium-sensing receptor (CaSR) is involved in maintaining calcium homeostasis via the regulation of parathyroid hormone (PTH) secretion. The associations between serum calcium concentrations, parathyroid hormone (PTH) level and CaSR polymorphism A986S have been studied, but results are inconsistent. Therefore, we performed a meta-analysis to clarify the role of this polymorphism on this topic. Weighted mean difference (WMD) and 95% confidence interval (CI) were calculated with random-effects model or fixed-effects model based on the heterogeneity analysis. Overall 2820, 1135 and 3149 healthy individuals were included for total calcium concentration, ionized calcium concentration and PTH level meta-analyses, respectively. Most of the individuals in this meta-analysis were healthy women. Healthy individuals with the AS + SS genotype had significantly higher total and ionized calcium concentrations than those with the AA genotype. However, there was no statistical significance concerning serum PTH level. The pooled WMD for total calcium concentration was 0.028 (95% CI: 0.012-0.045, P = 0.001); for ionized calcium concentration was 0.016 (95% CI: 0.013-0.020, P < 0.0001); and for PTH level was − 0.027 (95% CI: −0.360-0.306, P = 0.874). In conclusion, our meta-analysis indicates that the CaSR A986S polymorphism might be associated with total and ionized calcium concentrations in healthy individuals.     

Serum tolbutamide and chlorpropamide concentrations in patients with diabetes mellitus

A selective and sensitive gas chromatographic technique was used to measure the steady-state serum concentrations of tolbutamide and chlorpropamide in 97 patients with maturity-onset diabetes mellitus who had been taking these drugs (37 tolbutamide, 60 chlorpropamide) for at least a year. No other antidiabetic agents had been given. The serum tolbutamide concentrations varied widely between the patients (from close to zero to 370 μmol/l (100 μg/ml)), yet the variation in dosage was only sixfold (0·5-3·9 g daily). The serum chlorpropamide concentrations varied even more widely (from close to zero to 882 μmol/l (244 μg/ml)), though the dosage variation was fourfold (125-500 mg daily). There was no systematic relation between dosage and serum concentrations of the drugs.Only 2 (5·4%) of the tolbutamide-treated patients and 10 (16·7%) of the chlorpropamide-treated patients had normal fasting blood glucose concentrations (below 5·5 mmol/l (99 mg/100 ml)), and fewer than half had values below 8·0 mmol/l (144 mg/100 ml). In most cases, therefore, the treatment was insufficient.There was no significant difference in mean fasting blood glucose concentrations between the two treatment groups. The mean steady-state concentration of chlorpropamide, however, was significantly higher than that of tolbutamide. Thus, contrary to common belief, the intrinsic activity of chlorpropamide is apparently not greater than that of tolbutamide. The alleged greater potency of chlorpropamide seems to be related wholly to kinetic differences, such as the less extensive metabolic degradation and slower elimination of the drug.We conclude that treatment with sulphonylureas in conventional dosage is far from optimal and that monitoring the concentrations of these drugs in the blood may help to improve their efficacy.