Immunological and C-peptide studies of patients with diabetes in northern Ethiopia: existence of an unusual subgroup possibly related to malnutrition.

AIMS/HYPOTHESIS: Surveys in northern Ethiopia have demonstrated that apparent type 1 diabetes occurs more frequently than elsewhere in Africa and, indeed, in other parts of the world. We therefore investigated in detail a cohort of diabetic patients from this region to clarify the nature of this type of diabetes. METHODS: All patients attending the diabetic clinic at Mekelle Hospital in the Tigray region of northern Ethiopia were investigated over a 6 week period. Clinical, demographic and anthropometric data were collected, as well as measurements of HbA(1c), fasting lipid profile, fasting serum C-peptide and serum markers of beta cell autoimmunity, i.e. islet antigen-2 and GAD antibodies (GADA). RESULTS: Of 105 patients seen, 69 (66%) were on insulin treatment and had been from or close to diagnosis. Their median age and diabetes duration were 30 and 5 years, respectively, with a male excess of 2:1. Median BMI was 20.6 kg/m². Despite these clinical characteristics suggestive of type 1 diabetes, only 42 of 69 (61%) patients were C-peptide-negative and 35% GADA-positive. Overall, 38 (36%) of the total group (n = 105) had immunological or C-peptide characteristics inconsistent with typical type 1 or type 2 diabetes. The clinical characteristics, local prevalence of undernutrition, and GADA and C-peptide heterogeneity suggest a malnutrition-related form of diabetes. CONCLUSIONS/INTERPRETATION: Not all patients in northern Ethiopia with apparent type 1 diabetes appear to have the form of disease seen in Europids; their disease may, in fact, be related to malnutrition.

Laboratory measurement of testosterone.

Plasma testosterone concentrations in men, first quantified nearly half a century ago, are now measured routinely as a primary index of androgen status. Most clinical laboratories employ a multichannel, fully automated analyzer. Current evidence suggests that these analyzers are capable of satisfactorily quantifying the concentration of total plasma testosterone in men. Newer technology, in the form of tandem mass spectrometry, may, in the future, replace these automated platforms, providing a more specific estimate of testosterone concentration. When concentrations of plasma testosterone are found to be around the lower limit of normal ( 9.0 nmol/l; microg/l=nmol/lx0.288), some measure of bioactive testosterone should be sought. This may be a free (non-protein-bound) or bioavailable (free plus albumin-bound) testosterone and may be measured (laborious and time-consuming and therefore unsuited to routine clinical laboratories) or calculated using any one of a variety of mathematical expressions. Sampling for the estimation of plasma testosterone should be carried out in the morning, before 11:00 h, to obviate the effect of the marked diurnal variation in testosterone production. In samples found to have an equivocal concentration (7.0-12.5 nmol/l) at least one more estimate should be obtained to account for the possible significant intra-individual variability. Although it is generally accepted that the concentrations of total, free and bioavailable testosterone decline as men age, the majority of elderly men have testosterone levels in the young adult range (9.0-35 nmol/l) and some maintain a diurnal rhythm. Salivary testosterone offers a non-invasive estimate of free testosterone but there does not appear to be an immediate demand for a routine salivary testosterone service.

Biological variation of total testosterone, free androgen index and bioavailable testosterone in polycystic ovarian syndrome: implications for identifying hyperandrogenaemia.

OBJECTIVE: Hyperandrogenaemia is one of the three Rotterdam consensus diagnostic criteria for polycystic ovarian syndrome (PCOS) and may be measured by estimation of total testosterone, free androgen index (FAI) or bioavailable testosterone (BioT). The aim of this study was to compare the biological variability of total testosterone with that of the biological variability of both the FAI and BioT, to determine the least variable measurement for clinical practice. DESIGN: Comparative study. PATIENTS: Blood samples were collected after an overnight fast at 4-day intervals on 10 consecutive occasions from 12 PCOS patients and 11 weight- and age-matched control women. MEASUREMENTS: Duplicate samples of stored serum were analysed for total testosterone, SHBG and BioT in a single batch. RESULTS: The PCOS group had a significantly higher median BioT, FAI and total testosterone than controls. In both the PCOS and control groups, the intraindividual variance was small and similar for BioT and FAI. There was no significant difference between the within-subject biological coefficient of variation (CV(I)) for BioT, FAI and total testosterone. The maximum and minimum critical differences were +58% and -37% for BioT and +70% and -40% for FAI, respectively. CONCLUSION: FAI appears to be the better diagnostic marker to distinguish hyperandrogenism in patients with PCOS, but once diagnosis has been made, all three methods should be equally good in monitoring further changes in the androgen status.

Hypoadrenalism is not associated with early mortality during tuberculosis treatment in Malawi.

SETTING: In the developing world, early mortality within 1 month of commencing tuberculosis (TB) treatment is high, particularly with human immunodeficiency virus (HIV) co-infection. In Malawi, 40% of those who die do so in the first month of treatment. Reasons remain unclear and may include delayed diagnosis, opportunistic infections, immune restoration inflammatory syndrome (IRIS) or malnutrition. One possible contributing factor is underlying hypoadrenalism associated with TB-HIV, exacerbated by rifampicin (RMP) induction of P450 and glucocorticoid metabolism. OBJECTIVE: To assess the prevalence of hypoadrenalism in TB patients before and after commencement of TB treatment, and relationship with early mortality. DESIGN: Prospective descriptive study assessing hypoadrenalism before and after anti-tuberculosis treatment, HIV status and outcome up to 3 months post-treatment. RESULTS: Of 51 patients enrolled, 29 (56.9%) were female (median age 32 years, range 18-62). Of 43 patients HIV-tested, 38 (88.3%) were HIV-positive and 15.7% died within the first month. At 3 months, 11 (21.6%) were known to have died. Adequate cortisol levels were found in 49/51 (95.9%) before commencing RMP. Neither of the two with reduced response died. All 34 patients revealed adequate cortisol responses at 2 weeks. CONCLUSION: No evidence of hypoadrenalism was found in this first study to assess adrenal function and outcome of anti-tuberculosis treatment.

Greater antiarrhythmic activity of acute 17beta-estradiol in female than male anaesthetized rats: correlation with Ca2+ channel blockade.

BACKGROUND AND PURPOSE: Female sex hormones may protect pre-menopausal women from sudden cardiac death. We therefore investigated the effects of the main female sex hormone, 17beta-estradiol, on ischaemia-induced cardiac arrhythmias and on the L-type Ca2+ current (ICaL). EXPERIMENTAL APPROACH: In vivo experiments were performed in pentobarbital-anaesthetized rats subjected to acute coronary artery occlusion. ICaL was measured by the whole-cell patch-clamp technique, in rat isolated ventricular myocytes. KEY RESULTS: Acute intravenous administration of 17beta-estradiol as a bolus dose followed by a continuous infusion, commencing 10 min before coronary artery occlusion, had dose-dependent antiarrhythmic activity. In female rats 300 ng kg(-1) + 30 ng kg(-1) min(-1) 17beta-estradiol significantly reduced the number of ventricular premature beats (VPBs) and the incidence of ventricular fibrillation (VF). A ten fold higher dose of 17beta-estradiol was required to cause similar effects in male rats. In vitro 17beta-estradiol reduced peak ICaL in a concentration-dependent manner. The EC50 was ten-fold higher in male myocytes (0.66 microM) than in females (0.06 microM). CONCLUSIONS AND IMPLICATIONS: These results indicate that 17beta-estradiol has marked dose-dependent antiarrhythmic activity that is greater in female rats than in males. A similar differential potency in blocking ICaL in myocytes from female and male rats can account for this effect. This provides an explanation for the antiarrhythmic activity of 17beta-estradiol and gender-selective protection against sudden cardiac death.

Analytical and physiological factors affecting the interpretation of serum testosterone concentration in men.

Most hospital laboratories estimate the concentration of total circulating testosterone using a non-extraction method on an automated multi-channel immunoassay analyser supplied by a small number of multi-national diagnostic companies. Although these platforms offer advantages of quick turnaround times, small volume sampling and random access analysis, proficiency testing schemes suggest the quality of results produced remains similar to that of the early manual radioimmunoassay. An estimate of the bioavailable, non-sex hormone binding globulin (SHBG) bound fraction of circulating testosterone, be that the free or the free plus albumin-bound, may be a better index of gonadal status than total testosterone alone, especially when a borderline hypogonadal level of total testosterone is found, and may avoid misclassification of hypogonadal or eugonadal men. Free or bioavailable testosterone may be calculated or measured. The free androgen index may not give a true reflection of androgen status in men. In the interpretation of serum testosterone concentrations with results >40 nmol/L, the possibility of exogenous administration or abuse needs to be considered. The marked diurnal rhythm in total testosterone should also be taken into account. There may be a diminution of testosterone secretion with advancing age, but the great majority of older men have a circulating total testosterone concentration well within the accepted reference intervals established for younger men. As testosterone concentration may fluctuate markedly both seasonally and from day to day, it may be judicious to measure levels on more than one occasion. Provided that estimates of serum testosterone are unequivocally eugonadal (12.5-40 nmol/L) or hypogonadal (<7.0 nmol/L), results produced by routine automated immunoassays will in all probability give a satisfactory assessment of androgen status in men.Routine biochemical assessment of gonadal function in men should include measurement of early morning luteinizing hormone, follicle stimulating hormone, prolactin and SHBG together with total testosterone, and if necessary some estimate of bioactive testosterone.

Low-dose transdermal testosterone therapy improves angina threshold in men with chronic stable angina: A randomized, double-blind, placebo-controlled study.

BACKGROUND: Experimental studies suggest that androgens induce coronary vasodilatation. We performed this pilot project to examine the clinical effects of long-term low-dose androgens in men with angina. METHODS AND RESULTS: Forty-six men with stable angina completed a 2-week, single-blind placebo run-in, followed by double-blind randomization to 5 mg testosterone daily by transdermal patch or matching placebo for 12 weeks, in addition to their current medication. Time to 1-mm ST-segment depression on treadmill exercise testing and hormone levels were measured and quality of life was assessed by SF-36 at baseline and after 4 and 12 weeks of treatment. Active treatment resulted in a 2-fold increase in androgen levels and an increase in time to 1-mm ST-segment depression from (mean+/-SEM) 309+/-27 seconds at baseline to 343+/-26 seconds after 4 weeks and to 361+/-22 seconds after 12 weeks. This change was statistically significant compared with that seen in the placebo group (from 266+/-25 seconds at baseline to 284+/-23 seconds after 4 weeks and to 292+/-24 seconds after 12 weeks; P:=0.02 between the 2 groups by ANCOVA). The magnitude of the response was greater in those with lower baseline levels of bioavailable testosterone (r=-0. 455, P:<0.05). There were no significant changes in prostate specific antigen, hemoglobin, lipids, or coagulation profiles during the study. There were significant improvements in pain perception (P:=0.026) and role limitation resulting from physical problems (P:=0.024) in the testosterone-treated group. CONCLUSIONS: Low-dose supplemental testosterone treatment in men with chronic stable angina reduces exercise-induced myocardial ischemia.

Testosterone replacement-induced hyperprolactinaemia: case report and review of the literature.

Half of all men with prolactin (PRL)-producing macroadenomas present with hypogonadism, decreased libido and impotence, and therefore require testosterone replacement. However, very little is known about the effect of testosterone on prolactinomas. We report a case of an 18-year-old obese man who presented with hypogonadism and hyperprolactinaemia and underwent a transphenoidal hypophysectomy after a computer tomography scan showed the presence of a suprasellar macroadenoma. On separate occasions, we documented a rise in PRL when testosterone replacement was started and a fall in PRL when testosterone replacement was stopped (r = 0.6090, P = 0.0095). Furthermore, imaging studies suggested the possibility of tumour re-growth after testosterone therapy. We hypothesize that the exogenous testosterone was aromatized to oestradiol, which stimulated the release of PRL by the anterior pituitary. This was supported by the increase in oestradiol levels after testosterone replacement, although statistical significance was not achieved due to the availability of only a few data points. This case highlights the need to be aware of testosterone-replacement-induced hyperprolactinaemia, an under-recognized complication of androgen replacement in this setting. The use of aromatase inhibitors together with testosterone-replacement therapy or the use of non-aromatizable androgens might be indicated in such patients. Taken together, this report and previous studies show that dopamine agonists apparently do not suppress the hyperprolactinaemia induced by testosterone replacement.

Treatment of acromegaly with bromocryptine.

Four men and 4 women with active acromegaly were treated with bromocryptine for 4 to 5 weeks. Serum growth hormone levels response to a glucose load were measured before and in the last weed of treatment. In only 1 patient was the grwotoh hormone response rendered normal by the drug. This patient, but none of the others, also showed an improvement in glucose tolerance and a reductin of the raised serum insulin levels during the glucose load. In three of the 8 patients vomiting was troublesome side effect of treatment.

Basic fibroblastic growth factor stimulates prolactin secretion from human anterior pituitary adenomas without affecting adenoma cell proliferation.

The effects of human recombinant basic fibroblastic growth factor (bFGF) on the secretion and/or proliferation of 26 human anterior pituitary adenomas secreting PRL alone (6 tumors), PRL and GH (18 tumors), or GH alone (2 tumors) were examined. Secretory studies were performed over 4 h, 4 days, and 21 days, and proliferation studies over 4 days. The acute effect of bFGF on secretion over 4 h was examined in 10 tumors. bFGF (10 nmol/L) increased PRL compared to that in controls (100%) in 2 tumors (126% and 290%; P < 0.05) and PRL and GH in a third tumor (183% and 133%, respectively; P < 0.05), whereas 7 tumors remained unaffected. Fourteen tumors were studied over 4 days. bFGF (10 nmol/L) increased PRL secretion in 9 of 11 tumors (117-525%; P < 0.05) cosecreting PRL and GH and in all 3 tumors secreting PRL alone (156%, 183%, and 691%; P < 0.01). Dose-response curves with 0.1, 1, and 10 nmol/L bFGF in 2 of these tumors cosecreting GH and PRL showed that stimulation was achieved with all 3 concentrations. bFGF (10 nmol/L) stimulated GH secretion in 2 of 11 mixed tumors (159% and 196%, respectively; P < 0.05). In 2 tumors studied over 3 weeks, 5 nmol/L bFGF stimulated PRL secretion progressively without affecting GH secretion (106% and 207%; P < 0.05). Tissue proliferation was determined by double immunostaining after bromodeoxyuridine incorporation for 1 h in 7 tumors after 4 days. The labeling index did not exceed 1.2% in any tumor, and there was no effect of 10 nmol/L bFGF on the proliferation of adenoma cells. These results suggest that bFGF may have a paracrine role in the stimulatory regulation of PRL secretion in human pituitary adenomas, and these effects are most likely due to increased hormonal synthesis. An in vitro cell culture system can be used to study proliferative potential. However, bFGF is not mitogenic for human anterior pituitary adenomas secreting PRL and PRL plus GH in vitro.

The effect of free fatty acids on the in-vitro binding of testosterone in human plasma.

The effect of supraphysiological levels of free fatty acids (FFA) on the binding of testosterone to sex-hormone binding globulin (SHBG) and on non-SHBG binding in both male plasma and plasma from pregnant women was studied. Six FFAs were added to plasma as individual acids. No alteration in testosterone binding to SHBG could be demonstrated with any of the FFAs in either male plasma or plasma from pregnant women. When the same plasma was heated to destroy SHBG binding, a highly significant (P < 0.01) increase in non-SHBG binding was seen in both male plasma and plasma from pregnant women when the unsaturated FFAs oleic, linoleic and linolenic acids were added. No significant difference was demonstrated with the saturated FFAs, palmitic, stearic and arachidic acids.

The effect of clomiphene citrate treatment on cervical mucus and plasma estradiol and progesterone levels.

OBJECTIVES: To study the relationship between cervical mucus (CM) quality, postcoital test (PCT) results and plasma estradiol (E2) in clomiphene citrate (CC)-treated women. A subsidiary aim was to study the relationship between CM quality and plasma progesterone (P). DESIGN: Untreated women were compared with oligo-ovulatory patients given CC. SETTING: Infertility Clinic, Fazakerley Hospital, United Kingdom. PATIENTS, PARTICIPANTS: Fifty-one untreated patients and 31 women given CC. INTERVENTIONS: The treated women were given 50 mg/d CC from days 2 to 6 of their cycle. MAIN OUTCOME MEASURES: A CM assessment, a PCT, plasma E2, and P were performed at the anticipated time of ovulation based on at least two previous basal body temperature charts and menstrual patterns. RESULTS: In untreated women there was a very strong tendency for CM quality to improve with rising plasma E2 levels and to worsen with rising plasma P levels. There was a significant association between CM quality and PCT results. Similar results were found in CC-treated women, except that plasma E2 was very significantly higher and there was a significant inverse relationship between plasma E2 and CM quality. CONCLUSION: High plasma E2 in the periovulatory phase in CC-treated women is a marker for increased sensitivity to and continuing action of the antiestrogen. This impairs the quality of the CM.

Exaggerated effects of progestogen on uterine artery pulsatility index in Turner's syndrome patients receiving hormone replacement therapy.

OBJECTIVE: To investigate the effect of estrogen and progestogen on the resistance to blood flow in the uterine arteries of Turner's syndrome patients. DESIGN: Prospective clinical study. SETTING: A tertiary infertility clinic. PATIENTS: Five Turner's syndrome patients, six patients who had surgical castration, and five patients with idiopathic primary ovarian failure. INTERVENTIONS: The patients were treated with 2 mg E2 valerate to which 500 micrograms norgesterel was added for 10 days in a 28-day cycle. Transvaginal color Doppler was used to measure pulsatility index in the uterine arteries at eight regular intervals during a single cycle. MAIN OUTCOME MEASURE: Pulsatility index of the uterine arteries. RESULTS: The administration of norgesterel to Turner's syndrome patients resulted in an increase in pulsatility index that was significantly higher than in patients who had surgical castration (confidence interval = 0.17 to 2.42). CONCLUSION: The uterine arteries of Turner's syndrome patients are more sensitive to the tonic effect of progestogen. If manifest in cardiac arteries also this phenomenon may be partly responsible for the increased incidence of cardiovascular disease and shorter life expectancy in Turner's syndrome patients. To achieve optimal protection from cardiovascular disease, Turner's syndrome patients may benefit from hormone replacement treatment containing altered doses of estrogen and progestogen.

The long-term stability in whole blood of 14 commonly-requested hormone analytes.

Concentrations of 14 commonly-requested plasma hormones were measured in octuplicate in each of six subjects to determine their stability when unseparated from red cells for periods up to 1 week. Most of the analytes were stable when stored in this way and although statistically significant changes were recorded, in the great majority of cases the changes seen would have no bearing on the clinical interpretation of the result. In the light of these findings, we would confidently report results of analyses for these hormones in plasma that had remained in contact with red cells at ambient temperature for long periods of time.

Assays for prolactin: guidelines for the provision of a clinical biochemistry service.

This paper summarises the views of the authors on the provision of a prolactin assay service. We discuss the pathophysiology of prolactin secretion and the clinical indications that arise from that. We cover the rather complex issue of the definition of normal and elevated prolactin levels. From these considerations, certain guidelines on the analytical performance of prolactin assays and their provision in a clinical biochemistry service are given. The extent to which currently available methods and performance as revealed by the UK External Quality Assessment Scheme (EQAS) match these guidelines are described and certain conclusions are reached. Finally, probable future developments are briefly discussed. The main conclusions and recommendations are as follows: Reagents of appropriate quality are available to enable prolactin immunoassays to be provided in UK clinical biochemistry laboratories. These are provided either separately or in the form of kits from both commercial and NHS sources. There is no requirement for individual laboratories to undertake their own antiserum production or prolactin iodination. Acceptable performance (as defined using internal QC procedures and the UK EQAS) is achievable using these reagents/kits, although one commercial kit shows a consistent marked negative bias. Reference ranges, including 'normal ranges', show considerable between-centre variability. Many centres have not established their own ranges, even those using in-house methods. Reference ranges for use in clinical biochemistry laboratories are proposed in this report. Some general guidance on the provision of a prolactin service is given, although this does not differ in principle from that appropriate for other peptide hormone analytes. There is no evidence that centres with small workloads perform any worse than average, although it may be more cost-efficient for such centres to send the samples elsewhere. As with other peptide analytes, non-isotopic immunometric methodology is likely to replace current radioimmunoassay methods in the near future.

Analysis of fecal neutral steroids and bile acids in humans on constant fat diet.

A method is described for the separation and quantification of fecal neutral steroids and fecal bile acids. The fecal extract is separated into the neutral steroid fraction and bile acid fraction with ionexchange resin columns. The principal neutral steroids and bile acids are then separated and quantitated by thin-layer chromatography. Values for the fecal neutral steroids, cholesterol, coprostanol and coprostanone and fecal bile acids, deoxycholic acid and lithocholic acid of 5 subjects on a constant fat diet for a 3-week period are presented.