Plasma Magnesium Concentration in Primary Hyperparathyroidism

The plasma magnesium concentration has been determined in 73 patients with primary hyperparathyroidism. In most patients it lay within the normal range (1·7-2·3 mg./100 ml.), but in five it was less than 1·6 mg./100 ml. These patients had relatively high urinary magnesium outputs, and one of them, studied in greater detail, failed to retain parenterally administered magnesium. Hence hypomagnesaemia in hyperparathyroidism may be associated with a defect in renal magnesium conservation, which may be reversible.     

Measurement of Plasma Digoxin Concentration by Radioimmunoassay

A rapid, sensitive, and precise method for measuring the plasma digoxin concentration has been developed with the radioimmunoassay technique. Seventy patients receiving digoxin were shown to have plasma digoxin concentrations between 0·4 and 5 ng./ml. Preliminary studies show that though there is a positive correlation between total daily dose and the plasma digoxin concentration, the relationship is not close, and a relatively wide range of plasma digoxin concentrations appear to be consistent with effective digitalization.     

实验动物血及组织游离氨基酸含量

本文报告实验动物血及组织游离氨基酸含量,结果表明,实验狗和Wistar大鼠血游离氨基酸含量比较恒定。实验兔组织游离氨基酸含量普遍高于血。     

Pregnancy Alters Diurnal Variation of Plasma Glucose Concentration

Human pregnancy introduces a diurnal variation of fasting plasma glucose concentrations, with significantly lower values found after a daytime fast of eight hours compared with a night-time fast of the same duration. The diurnal variation of plasma glucose clearance, found in nonpregnant subjects, is not demonstrable during pregnancy. Insulin tolerance does not exhibit a circadian valuation but is substantially decreased during pregnancy.     

Collection and Interpretation of Plasma Leptin Concentration Data in Humans

JENSEN, MICHAEL D, DONALD HENSRUD, PETER C. O'BRIEN, AND SØREN NIELSEN. Collection and interpretation of plasma leptin concentration data in humans. Obes Res. Objective: To reassess the relationship between body fat and plasma leptin concentrations when a) replicate measures of leptin are made; b) energy intake is controlled at isoenergetic levels before the study; and c) body fat and percent body fat are measured with dual energy X-ray absorptiometry (DXA). Research Methods and Procedures: Two separate studies were conducted. In the first study, four plasma samples were collected for measurement of leptin over 30 minutes on a single day in 43 lean and obese men and women. For the second study, plasma samples were collected on four consecutive days from a group of 50 lean and obese men and women. Percent body fat (and body fat mass) was related to log-transformed mean plasma leptin concentrations using linear regression analysis; multiple linear regression analysis was used to determine whether there was an effect of gender on this relationship, and the analysis of Choi was used to examine whether percent body fat or body fat mass better predicts plasma leptin concentrations. Results: For the first study, percent body fat was highly correlated (r = 0. 96, p<O. OOOl) with log-transformed mean leptin concentrations. No difference in the relationship between leptin and percent body fat in men and women was detected. The second study confirmed this observation; the relationship between In leptin and percent body fat was virtually identical (r = 0. 93, p<0. 001). Analysis of the pooled data suggests that percent body fat is a better predictor of plasma leptin concentration than body fat mass. The use of multiple (as opposed to a single) leptin measurements did not significantly improve the leptinhody fat relationship. Discussion: When robust body composition techniques and diet control measures are taken into consideration, the relationship between In plasma leptin concentrations and percent body fat is not different in men and women.     

The Use of Urograph for the Determination of Urea Nitrogen Concentration in Serum and Plasma

The accuracy and precision of Urograph, a commercial preparation of chromatography papers designed for the determination of urea nitrogen in plasma and serum, were assessed. Results of duplicate determinations were compared with those of two acceptable quantitative procedures, (1) automated diacetyl monoxime and (2) modified Van Slyke and Cullen analysis. Values for serum specimens obtained by Urograph were significantly higher than those found by the Autoanalyzer method. The confidence limits for the Urograph procedure ranged from 12.5% for plasma to 26.6% for sera, whereas the corresponding values were 6.9% and 7.0% for Autoanalyzer. This lack of precision with Urograph appeared to be due mainly to the presence of a few strips in which only partial migration occurred. The papers yielded low values following 81/2 months of storage in the refrigerator; the test was temperature-sensitive.     

The Effect of Concentrate Feeding on Calcium Metabolism and Plasma Gastrin Concentration in Parturient Cows

The effect of concentrate feeding on calcium metabolism was studied in pregnant cows. The concentrate (5 kg/day) was added to the diet about three weeks before expected calving. A control group was fed only hay during the whole dry period. It was earlier observed in sheep that concentrate feeding was followed by a disturbance in calcium homeostasis, but no such disturbances were observed in the cows. The concentrate fed cows consumed 50 % more calcium than the controls and were found to mobilize less calcium from the skeleton immediately after calving. There was no evidence for the theory that the gastro-intestinal hormone gastrin is involved in calcium homeostasis in the parturient cow.     

Plasma Digoxin Concentration in Children with Heart Failure

A dosage schedule for digoxin medication is presented which has proved effective and safe in children of different ages with heart failure due to a variety of cardiac conditions. The plasma digoxin concentrations during maintenance therapy, using this schedule, agree closely with previously reported therapeutic adult plasma concentrations, though the results do not exclude the efficiency and safety of higher doses. A twice-daily dosage regimen is suggested.     

Relationship Between Muscle Sympathetic Nerve Activity and Plasma Leptin Concentration

SNITKER, SØREN, RICHARD E PRATLEY, MARGERY NICOLSON, P ANTONIO TATARANNI, ERIC RAVUSSIN, Relationship between muscle sympathetic nerve activity and plasma leptin concentration. In humans, basal muscle sympathetic nerve activity (MSNA), a direct measure of sympathetic nervous outflow, is correlated with percentage of body fat. The underlying physiological mechanism is unknown. On the basis of the observation that leptin increases sympathetic nervous outflow in the oblob mouse, we hypothesized that leptin, a hormone secreted by the adipose tissue, may act as a peripheral signal to increase sympathetic nervous outflow from the central nervous system. We therefore tested whether basal MSNA is correlated with plasma leptin concentration. Fasting plasma samples and recordings of basal MSNA in the peroneal nerve were obtained from 37 healthy, nondiabetic men (35 whites and 2 Mexican-Americans; 29 ± 7 years, 86 ± 14 kg, 24 ± 10% body fat; mean ± SD) who were fed a weight-maintenance diet on a metabolic ward. As expected, plasma leptin concentration (geometric mean, 6.4 ng/mL; 95% confidence interval, 4.6 ng/mL to 9.0 ng/mL) correlated with % body fat (r=0.93, p<0.001). Basal MSNA was 31.6 ± 10.0 bursts/min and correlated with % body fat (r=0.53, p<0.001) and with plasma leptin concentration (r=0.44, p<0.01). In conclusion, the results demonstrate a correlation between MSNA and plasma leptin concentration of a magnitude similar to that between MSNA and % body fat. Leptin may therefore be the peripheral signal explaining the correlation between MSNA and % body fat. A full understanding of the relationship between leptin and the activity of the sympathetic nervous system requires further studies, including the administration of leptin in humans.     

Concentration and Composition of Serum and Plasma Glycosaminoglycans in Domestic Animal Species

Acid glycosaminoglycans (GAGs) were isolated from serum and/or plasma of some domestic animals and the composition of the isolated GAG mixtures were studied. Mean values of total GAG concentration, in terms of hexuronic acid, ranged from a maximum of about 12 mg/l in serum of calves, trained horses and sheep to about 9 mg/l in serum of cows and donkeys and in plasma of trained horses to about 6.5 mg/l in sedentary horse serum and rabbit plasma to a minimum of 4 mg/l in dog serum and sedentary horse plasma. Statistically significant differences in total GAG concentrations (P < 0.0005) were found in horses between plasma and serum and also between sedentary and trained subjects. Chondroitin sulphate was the main component in serum and plasma GAG mixtures, accounting for 81–84% of total GAGs in the examined animals, except in cow serum (72%), trained horse plasma (75.5%) and sheep serum (87%). Keratan sulphate-like structures, measured as galactose, ranged from 12% in sheep serum to 17% in cattle serum. Fucose was associated with galactose in GAG fractions, which supports the hypothesis that articular cartilage is among the sites of origin of circulating GAGs.     

帕罗西汀血药浓度检测方法研究进展

帕罗西汀为5-羟色胺（5-HT）阻断药,具有起效快、疗效好、不良反应低等优点,为目前临床上常用抗抑郁症药物。帕罗西汀疗效和不良反应与该药血药浓度密切相关,并且个体差异性较大。因此,研究开发专一性强、灵敏度高的血药浓度检测方法十分必要,具有重要的临床和实践意义。本文综述帕罗西汀血药浓度检测时血样的前处理方法,同时对高效液相色谱法和气相色谱法检测帕罗西汀血药浓度进展进行论述,为该领域的临床合理用药和相关领域的研究提供借鉴。     

Seminal Plasma Metals Concentration with Respect to Semen Quality

The aim of the current study was to assess relationships between multiple metals burden in human seminal plasma and semen quality parameters. Levels of five metals (lead, manganese, copper, arsenic, and selenium) in human seminal plasma were determined by inductively coupled plasma mass spectrometry (ICP-MS), and the correlations between the metal concentrations and semen parameters (sperm concentration, sperm motility rate, and sperm morphology) were analyzed. The activities of acid phosphatase (ACP) and of α-glucosidase in human seminal plasma were also determined. Of the 100 subjects, 21 had fertility problems according to the World Health Organization criteria and were designated as "abnormal group." Significant inverse correlations were found between the concentrations of Cu, As, Pb, and the sperm concentrations (r (Cu)?=?-0.312, P (Cu)?= 0.029; r (As)?=?-0.328, P (As)?= 0.021; r (Pb)?=?-0.377, P (Pb)?= 0.008). Moreover, the Cu, Mn, and Se concentrations were significantly higher in the abnormal group than that in the normal group (P (Cu)?= 0.024, P (Mn)?= 0.002, P (Se)?= 0.002). The ACP activity was significantly higher in the normal group than that in the abnormal group (P = 0.021). We also found a significantly negative correlation between α-glucosidase activity and the levels of As (r =?-0.367, P = 0.023). These findings provide evidence for relationships between human semen quality and metal exposures. These relationships are consistent with animal data, but additional human and mechanistic studies are needed.     

Zinc and Iron Concentration and SOD Activity in Human Semen and Seminal Plasma

The aim of the present study was to measure zinc (Zn) and iron (Fe) concentration in human semen and superoxide dismutase (SOD) activity in seminal plasma and correlate the results with sperm quality. Semen samples were obtained from men (N = 168) undergoing routine infertility evaluation. The study design included two groups based on the ejaculate parameters. Group I (n = 39) consisted of males with normal ejaculate (normozoospermia), and group II (n = 129) consisted of males with pathological spermiogram. Seminal Zn and Fe were measured in 162 samples (group I, n = 38; group II, n = 124) and SOD activity in 149 samples (group I, n = 37; group II, n = 112). Correlations were found between SOD activity and Fe and Zn concentration, and between Fe and Zn concentration. SOD activity was negatively associated with volume of semen and positively associated with rapid progressive motility, nonprogressive motility, and concentration. Negative correlation was stated between Fe concentration and normal morphology. Mean SOD activity in seminal plasma of semen from men of group I was higher than in seminal plasma of semen from men of group II. Fe concentration was higher in teratozoospermic males than in males with normal morphology of spermatozoa in group II. Our results suggest that Fe may influence spermatozoa morphology.