Double blind clinical and laboratory study of hypoglycaemia with human and porcine insulin in diabetic patients reporting hypoglycaemia unawareness after transferring to human insulin.

OBJECTIVES--To compare awareness of hypoglycaemia and physiological responses to hypoglycaemia with human and porcine insulin in diabetic patients who reported loss of hypoglycaemia awareness after transferring to human insulin. DESIGN--Double blind randomised crossover study of clinical experience and physiological responses during slow fall hypoglycaemic clamping with porcine and human insulin. SETTING--Clinical investigation unit of teaching hospital recruiting from diabetes clinics of five teaching hospitals and one district general hospital. SUBJECTS--17 patients with insulin dependent diabetes mellitus of more than five years'' duration who had reported altered hypoglycaemia awareness within three months of transferring to human insulin. MAIN OUTCOME MEASURES--Glycaemic control and frequency of hypoglycaemic episodes during two months'' treatment with each insulin. Glucose thresholds for physiological and symptomatic responses during clamping. RESULTS--Glycaemic control did not change with either insulin. 136 hypoglycaemic episodes (eight severe) were reported with human insulin and 149 (nine severe) with porcine insulin (95% confidence interval -4 to 2.5, p = 0.63). 20 episodes of biochemical hypoglycaemia occurred with human insulin versus 18 with porcine insulin (-0.8 to 1, p = 0.78). During controlled hypoglycaemia the mean adrenaline response was 138 nmol/l/240 min for both insulins; neurohormonal responses were triggered at 3.0 (SE 0.2) versus 3.1 (0.2) mmol/l of glucose for adrenaline and 2.5 (0.1) versus 2.5 (0.1) mmol/l for subjective awareness. CONCLUSIONS--These data suggest that human insulin per se does not affect the presentation of hypoglycaemia or the neurohumoral, symptomatic, and cognitive function responses to hypoglycaemia in insulin dependent diabetic patients with a history of hypoglycaemia unawareness.     

Unawareness of hypoglycemia by insulin-dependent diabetics

After several years of insulin therapy, about 20% of insulin-dependent diabetics have little or no perception of hypoglycaemia because of a loss of the adrenergic warning symptoms. This defect, poorly correlated with the presence of autonomic neuropathy, has been classically explained by a defect in the catecholamine secretion. We compared the hormonal counterregulation during hypoglycaemia induced by subcutaneous injection of insulin in 7 insulin-dependent diabetics with poor perception of hypoglycaemia and experiencing repeated episodes of severe hypoglycaemia (group A) and 7 insulin-treated diabetics with very good perception of hypoglycaemia and not experiencing severe hypoglycaemia (group B). Groups A and B were similar in terms of age, duration of diabetes, HbA1c level and degenerative complications. The glucagon levels were identical and non-reactive in the two groups. The basal levels and secretion peaks of adrenaline, noradrenaline, growth hormone and cortisol were similar between the two groups, but there was a significant delay in secretion in group A with a blood glucose threshold of adrenergic secretion of between 3.1 +/- 0.5 and 1.6 +/- 0.2 mmoles/l in group A and between 4.6 +/- 0.3 and 3.2 +/- 0.2 mmoles/l in group B (P less than 0.05). This delayed secretion could be explained by desensitisation of the hypothalamic glucostat and could be due to the frequency and/or severity of hypoglycaemic episodes.     

Intensified conventional insulin treatment and neuropsychological impairment.

OBJECTIVE--To assess whether intensified insulin treatment, with an increased frequency of hypoglycaemic episodes, leads to cognitive deterioration. DESIGN--Prospective randomised trial of intensified conventional treatment and standard treatment. SETTING--Outpatient clinic for patients with insulin dependent diabetes. SUBJECTS--96 patients with insulin dependent diabetes, high blood glucose concentrations, and non-proliferative retinopathy were randomised to intensified conventional treatment (n = 44) or standard treatment (n = 52). MAIN OUTCOME MEASURES--Glycated haemoglobin concentration (metabolic control); the number of hypoglycaemic episodes reported by patients at each visit; results of computerised neuropsychological tests performed at entry and after five years. RESULTS--Mean glycated haemoglobin concentration during the study was 7.2% (SE 0.1%) with intensified conventional treatment and 8.7 (0.1%) with standard treatment (p less than 0.001). During five years 34 (77%, 95% confidence interval 53% to 100%) of the patients given intensified treatment and 29 (56%, 36% to 75%) of the others had at least one episode of serious hypoglycaemia (p less than 0.05). The intensified conventional treatment group had a mean of 1.1 episodes of serious hypoglycaemia per patient per year compared with 0.4 episodes in the standard treatment group. Results of the neuropsychological tests were similar in the two groups after five years. CONCLUSIONS--Intensified conventional insulin treatment led to lower blood glucose concentrations and a higher frequency of hypoglycaemic episodes, but patients showed no signs of cognitive deterioration.     

Hypoglycaemia and counterregulation during childhood

Hypoglycaemia is particularly common in young children with type 1 diabetes mellitus yet the normal protective counterregulatory responses have been little studied in this age group. The studies reported have shown conflicting results, in part related to prior glycaemic control and also to the method of investigation used. Counterregulatory hormone responses during both spontaneous and experimentally induced episodes of nocturnal hypoglycaemia do appear to be blunted, which may be a function of sleep itself. Although studies of cognitive function have consistently shown defects in certain areas of neurocognitive performance, particularly in those children with early-onset diabetes or a prior history of severe hypoglycaemia, the contribution of nocturnal hypoglycaemia to the development of these impairments has not been evaluated. In young adults and adolescents, nocturnal hypoglycaemia has been linked to cardiac arrhythmia and the risk of sudden death. The development of new techniques for continuous subcutaneous glucose monitoring may allow detailed study of counterregulatory responses and symptom recognition in young children. Effective intensification of insulin therapy without an increased risk of hypoglycaemia may be possible using new insulin analogues or continued subcutaneous intravenous infusion (CSII), thus improving patient compliance and overall quality of clinical care.     

Prevalence and Incidence of Hypoglycaemia in 532,542 People with Type 2 Diabetes on Oral Therapies and Insulin: A Systematic Review and Meta-Analysis of Population Based Studies

Objective

To collate and evaluate the current literature reporting the prevalence and incidence of hypoglycaemia in population based studies of type 2 diabetes.

Research Design and Methods

Medline, Embase and Cochrane were searched up to February 2014 to identify population based studies reporting the proportion of people with type 2 diabetes experiencing hypoglycaemia or rate of events experienced. Two reviewers independently screened studies for eligibility and extracted data for included studies. Random effects meta-analyses were carried out to calculate the prevalence and incidence of hypoglycaemia.

Results

46 studies (n = 532,542) met the inclusion criteria. Prevalence of hypoglycaemia was 45% (95%CI 0.34,0.57) for mild/moderate and 6% (95%CI, 0.05,0.07) for severe. Incidence of hypoglycaemic episodes per person-year for mild/moderate and for severe was 19 (95%CI 0.00, 51.08) and 0.80 (95%CI 0.00,2.15), respectively. Hypoglycaemia was prevalent amongst those on insulin; for mild/moderate episodes the prevalence was 50% and incidence 23 events per person-year, and for severe episodes the prevalence was 21% and incidence 1 event per person-year. For treatment regimes that included a sulphonylurea, mild/moderate prevalence was 30% and incidence 2 events per person-year, and severe prevalence was 5% and incidence 0.01 events per person-year. A similar prevalence of 5% was found for treatment regimes that did not include sulphonylureas.

Conclusions

Current evidence shows hypoglycaemia is considerably prevalent amongst people with type 2 diabetes, particularly for those on insulin, yet still fairly common for other treatment regimens. This highlights the subsequent need for educational interventions and individualisation of therapies to reduce the risk of hypoglycaemia.     

Can insulin-treated diabetics be given beta-adrenergic blocking drugs?

Lack of awareness of hypoglycaemia leading to loss of consciousness is a serious problem in some insulin-treated diabetics, and beta-blocking drugs may increase this hazard. A prospective study was therefore carried out over eight months to determine the incidence of hypoglycaemic episodes in 50 insulin-treated diabetics taking beta-blockers, as compared with 100 diabetic controls matched for age, sex, and duration of diabetes. The incidence of loss of consciousness from hypoglycaemia was the same in both groups and was unrelated to the dose of beta-blocking drug used. Five patients taking beta-blockers and 10 controls had episodes of unconsciousness, but four of these patients taking beta-blockers had had similar episodes in the two years preceding treatment. It is concluded that beta-blocking drugs are generally safe in insulin-treated diabetics and that hypoglycaemic unconsciousness resulting from their use is rare.     

Neuroprotective Potential of Bacopa monnieri and Bacoside A Against Dopamine Receptor Dysfunction in the Cerebral Cortex of Neonatal Hypoglycaemic Rats

Neonatal hypoglycaemia initiates a series of events leading to neuronal death, even if glucose and glycogen stores return to normal. Disturbances in the cortical dopaminergic function affect memory and cognition. We recommend Bacopa monnieri extract or Bacoside A to treat neonatal hypoglycaemia. We investigated the alterations in dopaminergic functions by studying the Dopamine D1 and D2 receptor subtypes. Receptor-binding studies revealed a significant decrease (p < 0.001) in dopamine D1 receptor number in the hypoglycaemic condition, suggesting cognitive dysfunction. cAMP content was significantly (p < 0.001) downregulated in hypoglycaemic neonatal rats indicating the reduction in cell signalling of the dopamine D1 receptors. It is attributed to the deficits in spatial learning and memory. Hypoglycaemic neonatal rats treated with Bacopa extract alone and Bacoside A ameliorated the dopaminergic and cAMP imbalance as effectively as the glucose therapy. The upregulated Bax expression in the present study indicates the high cell death in hypoglycaemic neonatal rats. Enzyme assay of SOD confirmed cortical cell death due to free radical accumulation. The gene expression of SOD in the cortex was significantly downregulated (p < 0.001). Bacopa treatment showed a significant reversal in the altered gene expression parameters (p < 0.001) of Bax and SOD. Our results suggest that in the rat experimental model of neonatal hypoglycaemia, Bacopa extract improved alterations in D1, D2 receptor expression, cAMP signalling and cell death resulting from oxidative stress. This is an important area of study given the significant motor and cognitive impairment that may arise from neonatal hypoglycaemia if proper treatment is not implemented.     

Unawareness of hypoglycaemia and inadequate hypoglycaemic counterregulation: no causal relation with diabetic autonomic neuropathy.

OBJECTIVE--To examine the traditional view that unawareness of hypoglycaemia and inadequate hypoglycaemic counterregulation in insulin dependent diabetes mellitus are manifestations of autonomic neuropathy. DESIGN--Perspective assessment of unawareness of hypoglycaemia and detailed assessment of autonomic neuropathy in patients with insulin dependent diabetes according to the adequacy of their hypoglycaemic counterregulation. SETTING--One routine diabetic unit in a university teaching hospital. PATIENTS--23 Patients aged 21-52 with insulin dependent diabetes mellitus (seven with symptoms suggesting autonomic neuropathy, nine with a serious clinical problem with hypoglycaemia, and seven without symptoms of autonomic neuropathy and without problems with hypoglycaemia) and 10 controls with a similar age distribution, without a personal or family history of diabetes. MAIN OUTCOME MEASURES--Presence of autonomic neuropathy as assessed with a test of the longest sympathetic fibres (acetylcholine sweatspot test), a pupil test, and a battery of seven cardiovascular autonomic function tests; adequacy of hypoglycaemic glucose counterregulation during a 40 mU/kg/h insulin infusion test; history of unawareness of hypoglycaemia; and response of plasma pancreatic polypeptide during hypoglycaemia, which depends on an intact and responding autonomic innervation of the pancreas. RESULTS--There was little evidence of autonomic neuropathy in either the 12 diabetic patients with a history of unawareness of hypoglycaemia or the seven patients with inadequate hypoglycaemic counterregulation. By contrast, in all seven patients with clear evidence of autonomic neuropathy there was no history of unawareness of hypoglycaemia and in six out of seven there was adequate hypoglycaemic counterregulation. Unawareness of hypoglycaemia and inadequate hypoglycaemic counterregulation were significantly associated (p less than 0.01). The response of plasma pancreatic polypeptide in the diabetic patients with adequate counterregulation but without autonomic neuropathy was not significantly different from that of the controls (change in plasma pancreatic polypeptide 226.8 v 414 pmol/l). The patients with autonomic neuropathy had a negligible plasma pancreatic polypeptide response (3.7 pmol/l), but this response was also blunted in the patients with inadequate hypoglycaemic counterregulation (72.4 pmol/l) compared with that of the controls (p less than 0.05). CONCLUSIONS--Unawareness of hypoglycaemia and inadequate glucose counterregulation during hypoglycaemia are related to each other but are not due to autonomic neuropathy. The blunted plasma pancreatic polypeptide responses of the patients with inadequate hypoglycaemic counterregulation may reflect diminished autonomic activity consequent upon reduced responsiveness of a central glucoregulatory centre, rather than classical autonomic neuropathy.     

Hypoglycemic coma in chronic alcoholism]

The authors present two cases of chronic alcoholism in two female patients aged 41 and 52 years without diabetes mellitus, in whom hypoglycaemic coma occurred during the abstinence period. Hypoglycaemia in one patient occurred suddenly as a result of fasting within 24 hours following the last alcohol intake, whereas a severe hypoglycaemia in the second patient was developing progressively during 72 hours; patient did not eat much and the last meal took 24 hours before the onset of hypoglycaemic coma. Diagnosis of hypoglycaemic coma was suspected because as no alcohol or acetic acid smell were felt, no alcohol or methanol was detected in blood (tested only in one patient). Adrenergic reactions were not distinct (no excessive sweating, convulsions, tachycardia). The authors suggest, that a severe hypoglycaemia should be considered in patients suspected of alcoholism, and the treatment should start earlier with intravenous glucose administration.     

Influence of human insulin on symptoms and awareness of hypoglycaemia: a randomised double blind crossover trial.

OBJECTIVE--To investigate the apparent increased risk of severe hypoglycaemia associated with use of human insulin by comparing the pattern of symptoms of hypoglycaemia with human insulin and porcine insulin. DESIGN--Randomised controlled double blind crossover trial of treatment with human insulin and porcine insulin, with two treatment periods of six weeks. SETTING--Diabetes outpatient department of a university teaching hospital in Berne, Switzerland. PATIENTS--44 patients (25 men, 19 women) aged 14 to 60 years, with insulin dependent diabetes mellitus. All patients met the following criteria: receiving treatment with fast acting soluble insulin and long acting protamine insulin; performing multiple daily fingerstick blood glucose self measurements; and had stable glycaemic control with about one mild hypoglycaemic episode a week during the preceding two months. INTERVENTION--Patients were randomised to receive either human or porcine insulin for six weeks and were then changed over to the other type of insulin for a further six weeks. MAIN OUTCOME MEASURE--Questionnaire recording "autonomic" and "neuroglycopenic" symptoms that occurred during hypoglycaemic episodes confirmed by a blood glucose concentration less than or equal to 2.8 mmol/l. RESULTS--Insulin doses and blood glucose, glycated haemoglobin A1c, and fructosamine concentrations were similar during the two treatment periods. 493 questionnaires on hypoglycaemia (234 during treatment with human insulin and 259 during treatment with porcine insulin) were analysed. With human insulin patients were more likely to report lack of concentration (52% v 35%, p = 0.0003) and restlessness (53% v 45%, p = 0.004) and less likely to report hunger (33% v 42%, p = 0.016) than during treatment with porcine insulin. The difference in the pattern of symptoms during the two treatments was similar to that between the 12 patients with a history of recurrent hypoglycaemic coma and the 32 patients without such a history. CONCLUSIONS--The pattern of symptoms associated with human insulin could impair patients'' ability to take appropriate steps to avoid severe hypoglycaemia. Caution should be exercised when transferring patients from animal insulin to human insulin, and a large scale randomised trial of the two types of insulin may be justified.     

Monitoring of blood glucose concentration in subjects with hypoglycaemic symptoms during everyday life.

OBJECTIVE--To study the persistence of hypoglycaemic symptoms, changes in blood glucose concentrations, and the relation between reported symptoms and measured blood glucose values in functional hypoglycaemia. DESIGN--Re-evaluation of symptoms in patients admitted consecutively with suspected hypoglycaemia followed by a case-control study. SETTING--The Steno Memorial Hospital in Gentofte, Denmark, which specialises in the diagnosis and treatment of and research on endocrine disorders, including hypoglycaemia. PATIENTS--21 Subjects admitted consecutively with hypoglycaemic symptoms that were relieved by eating in whom insulinoma and other organic disorders presenting with hypoglycaemia had been ruled out. Twelve of these subjects with persistent symptoms entered the case-control study, as did a matched control group. INTERVENTIONS--Four days of monitoring blood glucose concentrations at home, six daily samples being taken in fixed relation to meals by the finger prick method. Extra samples were taken when symptoms occurred. MAIN OUTCOME MEASURES--Blood glucose concentration, glycated haemoglobin concentration, and within subject variation in measured values. RESULTS--After one to three years of observation 19 of the 21 subjects still had symptoms. Six out of 12 subjects experienced hypoglycaemic symptoms during the controlled study. Blood glucose concentration ranged from 3.7 mmol/l to 7.5 mmol/l during these episodes. Changes in blood glucose concentration, mean blood glucose concentrations at each time point, within subject variation in the measured values, and glycated haemoglobin concentration were not significantly different in all patients compared with the control subjects and in patients with symptoms during the study compared with controls. CONCLUSION--Hypoglycaemic symptoms during everyday life in apparently healthy subjects are persistent but are not related to chemical hypoglycaemia.     

Insulin-induced hypoglycaemia in an accident and emergency department: the tip of an iceberg?

In one year a prospective survey in a large accident and emergency department identified 204 admissions of adults with severe hypoglycaemia, 200 in insulin-treated patients. Ninety-six had one admission while 34 others were admitted on 104 occasions. Of the 130 patients, 111 attended diabetic clinics in Nottingham, forming 9% of a known clinic population of 1229 on insulin treatment. Since many other episodes of hypoglycaemia were presumably treated outside hospital, 9% a year is a minimum estimate of the incidence of severe hypoglycaemia in our area. The mean insulin dose was 1.2 units/kilogram/day for those admitted twice or more and 0.9 U/kg/day for those admitted once; these doses were significantly higher than those of an age-matched clinic population. A year after the latest admission with hypoglycaemia, the mean insulin dose in the group with two or more admissions had fallen to 0.8 U/kg/day, suggesting that over-treatment had been an important causal factor. A similarly high incidence has been reported in other studies, and we believe that it is due mainly to the inadequacy of conventional subcutaneous insulin treatment.     

Enhanced Dopamine D1 and D2 Receptor Gene Expression in the Hippocampus of Hypoglycaemic and Diabetic Rats

Hypoglycaemic coma and brain injury are potential complications of insulin therapy. Hippocampal neurons are particularly vulnerable to hypoglycaemic stress leading to memory impairment. In the present article, we have investigated the dopamine (DA) content, homovanillic acid (HVA)/DA turnover ratio, DA D₁ and DA D₂ receptors in the hippocampus of insulin-induced hypoglycaemic (IIH) and streptozotocin induced diabetic rats where brain functions are impaired. The DA content decreased significantly in hippocampus of diabetic, diabetic +IIH and control +IIH rats compared to control. The HVA/DA turnover ratio also increased significantly in diabetic, diabetic +IIH and control +IIH rats compared to control. Scatchard analysis using [³H] DA in the hippocampus showed a significant increase in DA receptors of diabetic, diabetic +IIH and control +IIH rats with decreased affinity. Gene expression studies using Real-time PCR showed an increased expression of DA D₁ and DA D₂ receptors in the hippocampus of hypoglycaemic and diabetic rats. Our results indicate that the dopaminergic system is impaired in the hippocampus of hypoglycaemic and hyperglycaemic rats impairing DA related functions of hippocampus. We observed a prominent dopaminergic functional disturbance in the hypoglycaemic condition than in hyperglycaemia compared to control. This dopaminergic dysfunction in hippocampus during hypoglycaemia and hyperglycaemia is suggested to contribute to cognitive and memory deficits. This will have clinical significance in the treatment of diabetes.     

Tryptophan and the control of plasma glucose concentrations in the rat.

1. Injection of L-tryptophan (750 mg/kg body wt.) led to pronounced hypoglycaemia in fed and 48 h-starved rats. 2. The hypoglycaemic effect is blocked by pretreament with p-chlorophenylalanine, compound MK-486 [Carbidopa: L-alpha-(3,4-dihydroxybenzyl)-alpha-hydrazinopropionic acid monohydrate] or methysergide, and potentiated by pargyline. 3. 5-Hydroxy-L-tryptophan is more potent and induces a more rapid hypoglycaemia than does tryptophan. Other tryptophan metabolites were not associated with hypoglycaemia. 4. Adrenalectomy increases, and acute experimental diabetes strongly decreases, the sensitivity of rats to tryptophan induction of hypoglycaemia. Diabetic animals were also insensitive to 5-hydroxytryptophan. 5. Metabolite concentration changes in the livers from tryptophan-treated 48h-starved and diabetic animals were consistent with a rapid inhibition of gluconeogenesis. This did not correlate with the hypoglycaemic response. 6. Tryptophan treatment was associated with a significant increase in the plasma [beta-hydroxybutyrate]/[acetoacetate] ratio; there were no changes in the plasma concentrations of urea, triacyglycerol, non-esterified fatty acids and glycerol. 7. These observations suggest that the hypoglycaemic action of tryptophan is mediated through formation of intracellular 5-hydroxytryptamine, and is unrelated to the inhibition of gluconeogenesis. It is unlikely that this increased synthesis of 5-hydroxytryptamine involves directly either the adrenal glands or the central nervous system.     

Short-term but not long-term hypoglycaemia enhances plasma levels and hepatic expression of HSP72 in insulin-treated rats: an effect associated with increased IL-6 levels but not with IL-10 or TNF–α

The inducible expression of the 70-kDa heat shock proteins (HSP70) is associated with homeostatically stressful situations. Stresses involving sympathetic nervous system (SNS) activation, including α₁-adrenergic agonists and physical exercise, are capable of inducing HSP70 expression and release of the HSP70 inducible form, HSP72. However, whether hypoglycaemia is capable of influencing HSP70 status under a stressful situation such as insulin-induced hypoglycaemia (IIH), which also involves SNS activation, is unsettled. Hence, we decided to investigate whether the predominant signal for HSP70 expression and delivery into the blood comes from either low glucose, high insulin, or both during short-term IIH (STIIH) and long-term IIH (LTIIH). Our data indicated that low glucose level (up to 1.56 ± 0.14 mM), but not insulin, is the triggering factor responsible for a dramatic rise in HSP72 plasma concentrations (from 0.15 ± 0.01 in fed state to 0.77 ± 0.13 ng/mL during hypoglycaemic episodes). This was observed in parallel with up to 7-fold increases in interleukin-6 (IL–6) but not interleukin-10 (IL–10) or tumour necrosis factor-α (TNF–α) at STIIH. Together, the observations may suggest that HSP72 is released under hypoglycaemic conditions as a part of the homeostatic stress response, whereas at long-term, both hypoglycaemia and insulin may influence HSP72 expression in the liver, but not in kidneys. Secreted extracellular HSP72 (eHSP72) may be purely a danger signal to all the tissues of the body for the enhancement of immune and metabolic surveillance state or actively participates in glycaemic control under stressful situations.     

Regional Amino Acid Distribution in Relation to Function in Insulin Hypoglycaemia

The amino acids glutamate, aspartate, gamma-aminobutyric acid (GABA), and glutamine were measured as their dansyl derivatives in whole brain and specific brain regions by a sensitive double-labelling technique at various times during the development of hypoglycaemic encephalopathy. Hypoglycaemia was induced by administration of insulin (100 i.u./kg) to 24-h fasted rats. No significant changes in glutamate, GABA, or glutamine were detected in whole brain at any time up to and including the onset of hypoglycaemic convulsions. In cerebral cortex, however, GABA levels were reduced to 65% or normal prior to the appearance of neurological symptoms of hypoglycaemia. Onset of symptoms (severe catalepsy and loss of righting reflex, but before the onset of convulsions) was accompanied by marked decreases of glutamate and glutamine in striatum and hippocampus. These regions, in addition to cerebral cortex, show the greatest vulnerability to hypoglycaemic insult, according to previous anatomical studies. Aspartate levels were significantly increased (p less than 0.01) in the cerebral cortex of convulsing animals, confirming a previous report. No changes were detectable in any of the amino acids studied in medulla-pons at any time during the progression of hypoglycaemia. Cerebral cortex and striatum showed a selective net loss of amino acids (2.2 and 3.5 mumol/g. respectively) prior to the onset of insulin-hypoglycaemic convulsions.     

Characteristics of the rat behavior following single and multiple exposures of the hypoglycemic insulin doses]

Rats behaviour in the "open field" changed in 2 hrs after a single episode of hypoglycaemia was abolished with glucose whereas no changes occurred in their stereotyped behaviour and intraspecies interaction. In 24 hrs quantitative parameters of the "open field" behaviour normalised although the behaviour still had an altered structure. At the same time, amphetamine-induced stereotyped behaviour's indices became reduced. These and other findings suggest some deeper behavioural changes in rats during their recovery from repeated hypoglycaemic episodes and absence of synchronisation of the insulin effects.     

Scintillation Scanning of Lungs in Preoperative Assessment of Carcinoma of Bronchus

Lung scans with the use of macroaggregated human serum albumin labelled with technetium-99m were carried out in 52 patients before thoracotomy.Forty-three patients had carcinoma of the bronchus. Tumours less than 2 cm. in diameter on the chest radiograph were not detected. Larger tumours showed defects in perfusion, ranging in size from the mass seen on the chest radiograph to almost absent perfusion of the entire lung. The extent of the defect in perfusion was closely related to involvement of the pulmonary vessels at the hilum by distortion, compression, or invasion by the tumour. Bronchial obstruction played a less important part in producing the defects.The larger the defect in perfusion the greater was the involvement of the hilar and mediastinal structures and the more extensive was the surgery required. When perfusion of the affected lung was less than one-third of the total the tumour was found to be unresectable.     

Risk of severe hypoglycaemia in insulin treated diabetic patients transferred to human insulin: a case control study.

OBJECTIVE--To examine whether transfer from animal insulin to human insulin is associated with an increased risk of severe hypoglycaemia. DESIGN--Matched case-control study of insulin treated diabetic patients admitted to hospital because of hypoglycaemia during 1984-7, the period when human insulin was introduced into treatment. SETTING--Case admissions and control admissions were obtained from eight public hospitals within the Swiss canton of Berne and a second control group comprised members of the Bernese section of the Swiss Diabetes Association. SUBJECTS--94 patients with insulin treated diabetes with a total of 112 admissions for hypoglycaemia during 1984-7 (case admissions), 182 patients with insulin treated diabetes seen in the same hospitals for reasons other than hypoglycaemia with a total of 225 admissions (control admissions), and 86 insulin treated diabetic patients who were members of the Bernese section of the Swiss Diabetes Association. MAIN OUTCOME MEASURES--Type of insulin used at time of admission, glycaemic control as measured by amount of glycated haemoglobin or glucose concentration; severity of hypoglycaemia. RESULTS--Treatment with human insulin at admission was more common in cases than controls (52/112 (46%) admissions v 77/225 (34%); p = 0.003). 116 out of 129 (90%) of admissions taking human insulin had been transferred from animal insulin, mainly because of non-availability of porcine insulins. The ratio of rate of hypoglycaemia in those taking human insulin to the rate in those taking animal insulin was 2.4 (95% confidence interval 1.3 to 4.4). Other risk factors for hypoglycaemia were a history of hypoglycaemic coma (rate ratio of history to no history 3.8, 2.3 to 6.4) and good glycaemic control (rate ratio of good to poor control 3.9, 1.4 to 7.5). With multivariate analysis the increase in rate ratio associated with use of human insulin rose to 3.0 (1.4 to 6.4). Comparison with the diabetes association controls also showed an increased risk associated with use of human insulin (2.2; 1.1 to 4.8). CONCLUSIONS--Transfer of treatment from animal insulin to human insulin was associated with an increased risk of severe hypoglycaemia. Caution should be exercised when transferring diabetic patients to human insulin. Further studies are required to elucidate why this effect occurs.     

Under restrictive conditions,can the widths of linear enamel hypoplasias be used as relative indicators of stress episode duration?

Linear enamel hypoplasia (LEH), a type of enamel defect reflecting nonspecific physiological stress, has traditionally been used by bioarchaeologists to assess human health. Initially, measurements of defect width were used to estimate the duration of stress episodes. More recently, methods of counting within-defect perikymata (enamel growth increments) were developed to more accurately assess duration. Because perikymata are often not continuously visible within defects, while widths can usually be measured, the primary purpose of this article was to determine if, under restrictive conditions, the widths of LEH defects might be used as relative indicators of stress episode duration. Using a set of dental replicas from the prehistoric Irene Mound (1150-1400 A.D.), this study also investigated potential sources of variation in defect widths and how often defect widths could be measured and within-defect perikymata counted. Of 120 defects, only 47 contained both measurable defect widths and total within-defect perikymata, while 79 had measurable defect widths. Regression analysis revealed that, for these 47 defects, defect widths were more strongly related to the total number of within-defect perikymata than they were to crown region or tooth type. Although wide prediction intervals indicated that a defect's width could not be used to predict the number of within-defect perikymata for an individual, narrower confidence intervals associated with hypothetical mean population widths suggested that mean defect widths might be used to rank populations in terms of relative average stress episode duration.