Chronic orchidectomy does not influence the sensitivity of the pituitary somatotropes to varying doses of GHRH administered intravenously to the adult male rhesus monkey

In the present study, the pituitary growth hormone (GH) response to graded doses of GH-releasing hormone (GHRH) was determined in intact (n = 3) and chronically orchidectomized (n = 3) adult rhesus monkeys (Mucaca mulatta). GHRH in doses of 0, 6.25, 12.5 and 25 microg/kg BW was infused through a teflon cannula implanted in the saphenous vein. Blood samples were collected 60 min before and 90 min after the injection of the neurohormone at 15 min intervals. All bleedings were carried out under ketamine hydrochloride anesthesia. The plasma levels of GH were determined by using AutoDELFIA time-resolved flouroimmunoassay, whereas plasma levels of testosterone and estradiol were determined using specific radioimmunoassay systems. The GH responses to GHRH were not significantly different between intact and chronically orchidectomized monkeys at any of the dose levels tested (p > 0.05). The administration of GHRH resulted in a significant (p < 0.05) stimulation of GH secretion at all the doses tested and in both the groups studied. In both intact and orchidectomized animals, the greatest response was observed at 6.25 microg/kg and no further increase was noted with the higher doses of GHRH. In conclusion, the present study suggests that chronic orchidectomy does not influence the sensitivity of the pituitary somatotropes to GHRH stimulation implying that the responsiveness of the pituitary somatotropes to GHRH is independent of testicular steroid modulation.

Association of Various Point Mutations as Risk Factors for Synthetic Graft Thrombosis in African American Hemodialysis Patients

Single-nucleotide polymorphisms in the genes that code for coagulation factor V (factor V (Leiden)) and II (prothrombin G20210A), as well as the methyltetrahydrofolate reductase (MTHFR) have been implicated in the majority of cases of hereditary thrombophilia. In our hemodialysis patient population, comprised mainly of African Americans, we have seen a high incidence of early vascular access thrombosis without any identifiable predisposing factors. In some instances, there is recurrent access thrombosis that may be related to an inherited condition. In this study we evaluated the presence of these gene mutations and their association with increased risk of recurrent vascular access thrombosis in our hemodialysis patient population. Our results show that factor V Leiden and factor II prothrombin point mutations did not appear to increase the risk of vascular access thrombosis in African Americans with end-stage renal disease on hemodialysis. Patients heterozygous for the MTHFR gene, also did not show a significant increased risk for synthetic graft thrombosis.

Minimal change glomerulonephritis following a wasp sting

We report the case of a young white male who developed the nephrotic syndrome after being stung by a wasp. A percutaneous renal biopsy was done revealing minimal change glomerulonephritis. The patient was treated with oral prednisone with resolution of proteinuria. Corticosteroids were gradually tapered, the patient did not experience a relapse, and remains in good health with normal renal function. Herein, we also include a review of the literature on wasp bite associated nephrotic syndrome in patients who underwent a renal biopsy.

Fluorescence polarization in homogeneous nucleic acid analysis II: 5'-nuclease assay

When the temperature and viscosity of the solvent is held constant, the degree of fluorescence polarization (FP) detected when a fluorescent dye is excited by plane polarized light depends mostly on the molecular weight of the dye molecule. By monitoring the FP of a fluorescent dye molecule, one can detect significant changes in the molecular weight of a fluorescent molecule without separation or purification. The 5'-nuclease (TaqMan) assay is a robust single nucleotide polymorphism genotyping method where an allele-specific probe that binds to a perfectly complementary target is cleaved by the 5'-nuclease activity of Taq DNA polymerase. Because the TaqMan probe is labeled with a fluorescent dye, it has high FP value when intact but a low FP value after cleavage. In this study, we compared the results of the 5'-nuclease assay based on standard fluorescence intensity readings and FP readings when genotyping 90 individuals with 20 single nucleotide polymorphisms. Our results show that FP is just as robust and reliable as the standard fluorescence detection method. Use of FP detection makes it possible to reduce the cost of TaqMan probes by abrogating the need for a fluorescence quencher.

Discovery of novel ansamycins possessing potent inhibitory activity in a cell-based oncostatin M signalling assay

We describe the isolation and characterisation of novel non-benzoquinone ansamycin metabolites related to geldanamycin from a culture of Streptomyces sp. S6699. The compounds possess potent inhibitory activity in a cell-based assay measuring inhibition of oncostatin M signalling in a reporter cell line utilising a secreted placental alkaline phosphatase (sPAP) readout. In this paper we report the isolation and structure elucidation of the compounds and describe some of their biological properties.

11Beta-hydroxysteroid dehydrogenase in the Dahl rat

Dahl salt sensitive (Dahl-S) rats develop hypertension soon after birth. The cause of the increased salt-sensitivity in the Dahl-S rat is unknown. The mineralocorticoid specificity of the kidney receptor is conferred by the activity of 11beta-hydroxysteroid dehydrogenase (11beta-HSD). There are two isoforms of 11beta-HSD (11beta-HSD1 and 11beta-HSD2). Deficiency or inhibition of 11beta-HSD2 causes sodium retention and hypertension. In the present study we measured the activity of hepatic and kidney 11beta-HSD1 in Dahl-S and R rats before and after the development of hypertension. The activity of 11beta-HSD1 in the liver was lower in the Dahl-S rats at 6 weeks of age (S = 8.01 +/- 0.89 v R = 11.91 +/- 0.84 nmol/mg protein/10 min (P < .02) but there was no difference at 10 weeks. In contrast, 11beta-HSD1 in the kidney was not different at 6 weeks but it was significantly lower in the Dahl-S rats at 10 weeks (S = 0.91 +/- 0.04 v R = 1.12 +/- 0.01 nmol/mg protein/10 min (P < .001). Plasma renin concentration was lower at 6 (6w) and 10 weeks (10w) in the Dahl-S rats: S-6w = 4.2 +/- 0.4 versus R-6W = 6.3 +/- 0.8 ng angiotensin I (AI)/mL/h (P < .04) and S-10w = 6.4 +/- 0.7 versus R-10w = 10 +/- 0.9 ng AI/mL/h (P < .009). Plasma aldosterone and corticosterone were not different between the two strains. Systolic blood pressure (SBP) in the Dahl-S rats was 124 +/- 3 mm Hg at 6 weeks and 241 +/- 6 mm Hg at 10 weeks (P < .001). SBP in the Dahl-R rats was 113 +/- 5 mm Hg at 6 weeks and 143 +/- 4 mm Hg at 10 weeks. In conclusion, Dahl-S rats have lower hepatic 11beta-HSD1 activity at 6 weeks of age and lower kidney 11beta-HSD1 at 10 weeks of age compared with Dahl-R rats of the same age. These findings suggest that diminished activity of both liver and kidney 11beta-HSD1 may play a role in the salt sensitivity and development of hypertension in the Dahl-S rat.

Stress and psychiatric disorder in rural Punjab. A community survey

BACKGROUND

The prevalence of psychiatric disorders in rural Punjab is unknown. Previous studies in rural areas elsewhere in the Indian subcontinent have yielded widely differing estimates.

METHOD

First-stage screening of a village near Gujar Khan used the Bradford Somatic Inventory and Self Reporting Questionnaire. Psychiatric interviews were conducted with stratified samples using the ICD-10 Diagnostic Criteria for Research.

RESULTS

It is estimated that 66% of women and 25% of men suffered from anxiety and depressive disorders. Levels of emotional distress increased with age in both genders. Women living in unitary households reported more distress than those living in extended or joint families. With younger men and women, lower levels of education were associated with greater risk of psychiatric disorders. Social disadvantage was associated with more emotional distress.

CONCLUSIONS

This study in rural Punjab confirms that findings of a previous study in Chitral, northern Pakistan, of high levels of emotional distress and psychiatric morbidity among women in rural areas of Pakistan.

Pulmonary mucormycosis in diabetic renal allograft recipients

Renal allograft recipients are prone to opportunistic infections due to their need of immunosuppression to prevent rejection. Mucormycosis is a rare opportunistic infection caused by a fungi of the order Mucorales. Risk factors predisposing to this disease include prolonged neutropenia, chelation therapy for iron or aluminum overdose, diabetes, and patients who are immunosuppressed. Life-threatening infections can occur, as this fungi has the propensity to invade blood vessel endothelium, resulting in hematologic dissemination. Early diagnosis and prompt aggressive therapy is imperative to achieve an improved outcome. We present two cases of pulmonary mucormycosis in diabetic renal allograft recipients who were treated successfully with amphotericin B and surgical resection of the lesions with preservation of their allograft function. In this era of intensified immunosuppression, we may see an increased incidence of mucormycosis in our transplant population.

Automated serial ECG comparison based on the Minnesota code

The Minnesota code was introduced in 1960, and since then, a number of computer programs have been written for classifying electrocardiograms according to the rules of the code. However, in 1982, extended rules for serial comparison based on the Minnesota code were published. This article presents the details of implementation of automated serial electrocardiographic comparison using the code. Its application in the West of Scotland Coronary Prevention Study, which was a double-blind trial of lipid lowering in 6.595 men, is also discussed.

Direct erosion of lumbar spine by an abdominal aortic aneurysm, resulting in paraparesis: unusual presentation. Case report

Abdominal aortic aneurysm is a condition affecting nearly 4% of the elderly population. It has a potential for producing a wide range of symptoms, including abdominal pain and back pain. The latter is particularly difficult to interpret in patients with chronic rheumatological conditions, and delayed diagnosis may be associated with a poor outcome. We present a patient with rheumatoid arthritis and chronic low back pain, who developed bilateral leg weakness and hesitancy of micturition, due to an abdominal aortic aneurysm invading the spine.

Heart rate variability in left ventricular hypertrophy

BACKGROUND

Electrocardiographic left ventricular hypertrophy and strain are associated with increased cardiac morbidity and mortality. Impaired cardiac autonomic function, assessed non-invasively by spontaneous heart rate variability on Holter monitoring, is associated with an increased risk of sudden death after myocardial infarction.

AIM

To study the effect of left ventricular hypertrophy on heart rate variability.

PATIENTS

36 controls and 154 patients with left ventricular hypertrophy (94 with hypertension and 60 with aortic valve disease).

SETTING

Tertiary referral centre.

METHODS

Heart rate variability was measured on 24 h Holter recordings by non-spectral methods. Left ventricular mass index and fractional shortening were measured by echocardiography.

RESULTS

Patients with left ventricular hypertrophy had a higher left ventricular mass index (P < 0.001) and reduced heart rate variability (P < 0.001) compared with those of the controls. A continuous inverse relation was apparent between heart rate variability and left ventricular mass index (r = -0.478, P < 0.001). Heart rate variability was not affected by age, the presence of coronary artery disease in patients with left ventricular hypertrophy, or beta blocker treatment for hypertension. Multivariate analysis showed that left ventricular mass index is the most important determinant of heart rate variability.

CONCLUSION

Heart rate variability is significantly reduced in patients with left ventricular hypertrophy secondary to hypertension or aortic valve disease. A continuous inverse relation exists between heart rate variability and left ventricular mass index. Impaired cardiac autonomic function in left ventricular hypertrophy may contribute to the mechanism of sudden death.

Activity of 11 beta-hydroxysteroid dehydrogenase in toad bladder: effects of 11-dehydrocorticosterone

11 beta-Hydroxysteroid dehydrogenase (11 beta-OHSD) transforms circulating glucocorticoids to their "biologically inert" 11-dehydro derivatives. Isoforms of 11 beta-OHSD with different cofactor requirements and biochemical properties [Michaelis constant (Km) and maximal velocity (Vmax)] exist in the kidney. Since epithelial cells derived from the toad bladder also contain this enzyme, we wished to further characterize its properties in prepared cell homogenates. 11 beta-OHSD from toad bladder demonstrated a clear preference for NAD+ over NADP+ as a cofactor similar to that observed in renal cortical collecting duct (CCD) cells. Furthermore, 11 beta-OHSD had a rapid onset of action. The apparent Km for corticosterone was 16.3 x 10(-8) M, a value comparable to that observed for enzyme from CCD, and a Vmax of 4.8 x 10(-12) mol.mg protein-1.min-1. The end product, 11-dehydrocorticosterone (compound A), influenced enzyme activity; it increased 11 beta-OHSD activity at corticosterone concentrations below the apparent Km for the enzyme and inhibited 11 beta-OHSD activity at corticosterone concentrations above the Km for the enzyme. The inhibitory effects of compound A appeared noncompetitive with an apparent equilibrium constant (Ki) of 2.8 x 10(-7) M. Consistent with its inhibitory action on 11 beta-OHSD, compound A (10(-6) M) enhanced the short-circuit current response to corticosterone (10(-7) M) in the intact toad bladder (experimental 2.03 +/- 0.33 vs. control 1.40 +/- 0.17 times above baseline; n = 7, P < 0.01). Thus 11 beta-OHSD in toad bladder resembles the isoform found in CCD, and compound A may be biologically important as a regulator of 11 beta-OHSD.

Methodology of ECG interpretation in the Glasgow program

This paper describes the methods currently used in Glasgow Royal Infirmary for computer analysis of electrocardiograms. The software is designed to analyse from 3 to 15 simultaneously recorded leads, with facilities for analysis of rhythm and serial changes. Options for Minnesota Code (with serial comparison) and XYZ lead interpretation are available.

Microbial transformations of steroids--VI. Transformation of testosterone and androstenedione by Botryosphaerica obtusa

The 7 beta progesterone-hydroxylating microorganism Botryosphaerica obtusa was tested for its ability to hydroxylate at this site the C-19 androstene-based compounds, androstenedione (androst-4-ene-3,17-dione) and testosterone (17 beta-hydroxyandrost-4-en-3-one). Only very limited 7 beta hydroxylation of both substrates was observed. The products included traces of 7 beta-monohydroxytestosterone and 6 beta,7 beta-dihydroxyandrostenedione from testosterone, and of 6 beta,7 beta-dihydroxyandrostenedione from androstenedione. 6 beta,7 beta-Dihydroxyandrostenedione does not appear to have been reported previously as a microbial transformation product. Both substrates were monohydroxylated in significant amounts at the isomeric 7 alpha site and at the 6 beta site. Testosterone was also significantly monohydroxylated at the 15 alpha site and in minor amounts at the 11 alpha and 12 beta sites. Some monohydroxytestosterones had also been oxidised at their 17-OH group, converting them into the corresponding monohydroxy androstenediones. The 7 alpha-hydroxy metabolites and 15 alpha-hydroxytestosterone being chemically demanding to synthesis are valuable microbial transformation products.

Microbial transformations of steroids--V. Transformation of progesterone by whole cells and extracts of Botryosphaerica obtusa

Members of the genus Botryosphaerica are reported 7 alpha steroid hydroxylators [1]. We found that the species B. obtusa efficiently hydroxylated progesterone in a 1-day transformation but it gave 7 beta-hydroxyprogesterone as the main product rather than the expected 7 alpha-hydroxy isomer, which was produced in only trace amounts. Also formed in minor amounts were 6 beta-, possibly 9 alpha- (see main text), 14 alpha- and 15 beta-monohydroxyprogesterones. The transformation mixtures included appreciable amounts of dihydroxylated progesterones which were mainly based on 7 beta-hydroxyprogesterone. The second hydroxyl group was at one of the minor monohydroxylation sites. The relative concentrations of the progesterone diols increased and those of the mono-alcohols concomitantly decreased when transformation was extended beyond 1 day. Monohydroxylated 6-dehydroprogesterones began to accumulate after about 3 days and these compounds seemed to have been formed by 6,7-dehydration of the dihydroxyprogesterones. We prepared mycelial cell-free extracts which were capable of transforming progesterone and retained the site-specificity of whole cells. These extracts converted 7 beta-hydroxyprogesterone to its 6-dehydro derivative, confirming that ring B desaturation occurs in this organism by dehydration. The dehydratase activity necessary for the conversion was separable from the hydroxylase activity by ultra-centrifugation. All hydroxylase activity co-sedimented with the membrane fraction, implying that steroid hydroxylation is effected by a membrane-bound enzyme(s). Dehydratase activity was present in both the pellet and the supernatant fractions, which suggests that it may involve a loosely bound, and easily removed, membrane-associated enzyme.

Microbial transformations of steroids--IV. 6,7-Dehydrogenation; a new class of fungal steroid transformation product

Microbial steroid dehydrogenation is quite common. The reaction seems to occur mainly in bacteria and usually results in hydrogen abstraction from positions C(1)-C(2) and/or C(4)-C(5) with occasional aromatisation of ring A. We have screened large numbers of fungal cultures for their ability to monohydroxylate steroids at unusual sites and in the course of our investigations we have identified seven fungal strains capable of dehydrogenating ring B of progesterone and androstenedione at positions C(6)-C(7). Microbiological dehydrogenation at this site seems not to have been reported previously. The structures of the metabolites isolated from progesterone, and the producing fungi, are: 6-dehydroprogesterone (Botryodiplodia theobromae), 11 alpha-hydroxy-6-dehydroprogesterone (Botryosphaerica obtusa, Mucor racemosus and Nigrospora sphaerica), 12 alpha-, 15 beta- and 16 alpha-hydroxy-6-dehydroprogesterones (B. obtusa) and 14 alpha-hydroxy-6-dehydroprogesterone (Apiocrea chrysosperma) [1]. From androstenedione we isolated 6-dehydroandrostenedione (Absidia coerulea and Curvularia lunata) and 6-dehydrotestosterone (C. lunata).

Microbial transformation of steroids--II. Transformations of progesterone, testosterone and androstenedione by Phycomyces blakesleeanus

Phycomyces blakesleeanus transformed progesterone, testosterone and androstenedione into mixtures of products. Five monohydroxylated metabolites were obtained in reasonable yields from the progesterone transformation. Only 7 alpha- and 15 beta-hydroxyprogesterone have been reported previously from this organism. We find that it gives these two metabolites and also 6 beta-, 14 alpha- and 15 alpha-hydroxyprogesterone as major products. Five compounds were also purified from testosterone transformation mixtures. Two of these were monohydroxylated, two were ring A dehydrogenation products, and two were oxidised at C-17. The products were identified as 6 beta-hydroxytestosterone, 7 alpha-hydroxytestosterone, androsta-1,4-diene-3,17-dione (1-dehydroandrostenedione), 17 beta-hydroxyandrosta-1,4-diene-3-one (1-dehydrotestosterone) and androstenedione. All five metabolites were produced in reasonable yields, although hydroxylation was the minor transformation in this case. Only two significant products were formed from androstenedione. Both were reduced at C-17; one was also monohydroxylated. They were testosterone and 14 alpha-hydroxytestosterone. The testosterone and androstenedione transformation products have not been reported previously for this organism. We also report for the first time the preparation of P. blakesleeanus cell-free extracts which transformed progesterone reasonably efficiently and faithfully in vitro, although the proportions of each product varied from one extract to another.

7B2, a new protein secreted by human functionless pituitary tumours, in vitro

A novel pituitary protein, 7B2, of approximately 180 amino acids has been suggested to colocalise with LH in the pituitary gonadotropes. Increased secretion of LH is known to occur in functionless pituitary tumours. We have therefore measured 7B2 immunoreactive equivalents in the 24-h medium of explant pituitary cultures prepared from 17 functionless, 20 somatotropic, 16 PRL secreting and 8 corticotropic adenomas. A synthetic fragment corresponding to amino acids 23-39 of 7B2 was used to raise antisera (rabbits), prepare radiolabel (chloramine T iodination) and also serve as the assay standard. 7B2-immunoreactive equivalents in the medium from the functionless tumours was 517 +/- 149 pmol/l, significantly higher than that of the somatotropic tumours (248 +/- 90 pmol/l, P less than 0.05), prolactinomas (108 +/- 37 pmol/l, P less than 0.001) and corticotropin producing adenomas (107 +/- 77 pmol/l, P less than 0.001) (one-way analysis of variance). Gel permeation chromatography of medium obtained from functionless tumours revealed two immunoreactive 7B2 peaks one eluting at a coefficient of 0.28 corresponding to that of normal human pituitary extract and another eluting at a coefficient of 0.59. Gel chromatography profiles of medium obtained from somatotropic tumours contained similar immunoreactive 7B2 peaks (elution coefficient 0.28 and 0.57). These findings demonstrate that 7B2-like material is secreted by pituitary adenomas in explant culture with the highest level from functionless tumour cultures.

Microbial transformations of steroids--I. Rare transformations of progesterone by Apiocrea chrysosperma

When Apiocrea chrysosperma is incubated with progesterone for 7 days in a peptone, yeast-extract medium, eight major metabolites are produced. Each compound has been purified and its structure determined by high-field 1D and 2D 1H nuclear magnetic resonance (NMR) spectroscopy. A clear synthetic pattern is recognisable. The products have been formed by multiple transformation reactions, usually double hydroxylations. Seven compounds are tertiary alcohols in which the hydroxyl group is located on the underside of the progesterone skeleton at either the axial 9 alpha- or the axial 14 alpha-site. One compound has hydroxyl groups at both these sites. Five metabolites are also secondary progesterone alcohols, the hydroxyl groups being at the 6 beta-, 15 alpha- or 15 beta-sites. Two compounds are monohydroxy metabolites; one is dehydrogenated in ring B and the other has lost the pregnane side-chain. The structures of the eight metabolites are 6 beta, 9 alpha-dihydroxyprogesterone; 6 beta, 14 alpha-dihydroxyprogesterone; 9 alpha, 14 alpha-dihydroxyprogesterone; 9 alpha, 15 beta-dihydroxyprogesterone, 14 alpha, 15 alpha-dihydroxyprogesterone; 14 alpha, 15 beta-dihydroxyprogesterone; 14 alpha-hydroxypregna-4,6-diene-3,20-dione and 15 alpha-hydroxyandrostene-3,17-dione. All compounds, except the last one, are biologically rare because they are not products of mammalian progesterone or androstenedione metabolism. They would be difficult to synthesise chemically. We believe that the compounds, 9 alpha, 15 beta-dihydroxyprogesterone; 14 alpha, 15 alpha-dihydroxyprogesterone and 14 alpha-hydroxypregn-4,6-diene-3,20-dione, have not been reported previously as microbial transformation products of progesterone.

The metabolism of aldosterone in kidney

Slices of kidney cortex and medulla from adrenalectomized male rats metabolized aldosterone to at least 4 peaks of polar metabolites as well as reduced metabolites. The majority of the products were ring A-reduced and shown chromatographically to consist of 5 alpha-reduced metabolites; significant quantities of 5 beta-reduced metabolites were also synthesized. Approximately half of the 5 alpha-reduced products cochromatographed with 3 beta,5 alpha-THA and the remainder with 5 alpha-DHA and/or 3 alpha,5 alpha-THA. The anti-mineralocorticoids, spironolactone and progesterone, inhibited renal synthesis of 5 alpha-reduced products of aldosterone by 80%. 5 beta-Reduction was also slightly inhibited. Corticosterone slightly inhibited synthesis of the 5 alpha- and 5 beta-reduced products. Corticosterone and progesterone significantly inhibited the renal synthesis of the polar metabolites of aldosterone, but the inhibition was not significant at this dosage of spironolactone. Interestingly, the nuclei and plasma membranes were shown to be the most active fractions for these aldosterone transformations. Importantly significant quantities of 5 alpha-DHA and/or 3 alpha,5 alpha-THA, which possess 1/10 and 1/30, respectively, of the antinatriuretic activity of aldosterone, were synthesized at these subcellular locations.