Biomedical subjects
Publications and source records attributed to S Fleming.
A case report of a 21-year-old patient with Mayer-von Rokitansky-Küster-Hauser syndrome is presented. A neovagina was created by drawing an olive into the vaginal grove and applying continuous tension via sutures passed at laparoscopy to a tensioning device on the anterior abdominal wall.
Several recent studies have demonstrated that ablation of genes of the renin-angiotensin system can have wide-ranging and sometimes unexpected effects. Renin is directly involved in blood pressure regulation and is encoded by a single gene in most mammals. Wild mouse strains and some inbred laboratory strains have a duplicated renin gene (Ren-2), the physiological significance of which is unclear. Significant differences exist in the structure and expression of these renin genes, but as yet, no distinct biological function that distinguishes these genes has been defined. We have used gene targeting to discover the effects of inactivating the duplicated (Ren-2) gene in strain 129 mice, and we show that mice lacking the Ren-2 gene are viable and healthy. There appear to be no histopathological differences in renin-expressing tissues between Ren-2-null mice and their controls. Studies of our Ren-2-null mice allow, for the first time, a direct evaluation of the ability of the Ren-1d gene to regulate blood pressure in the absence of expression of the Ren-2 enzyme. We observed no alteration to blood pressure in adult mice homozygous for the mutated Ren-2 gene, even though the concentration of active renin is increased and of prorenin is decreased in plasma of these mice. Ren-1d is therefore capable of regulating normal blood pressure and despite a different tissue expression profile, is functionally equivalent to Ren-1c.
There is limited information concerning bone mineral density (BMD) and its determinants across a wide spectrum of ages in African American females (AAF). Therefore, we have performed a cross-sectional study of 54 AAF and 39 Caucasian females (CF), aged 20-90 yr, to quantify femoral and lumbar bone mineral density, total body calcium, as well as the potential determinants of bone density. BMD decreased with age in all sites after age 40 yr in both racial groups. Bone density was greater in AAF than in CF, although there was considerable overlap between the two groups. There was no significant difference in the rate of age-related bone loss between the two groups. At the femoral neck, BMD was below the fracture threshold in 28% of the postmenopausal AAF compared to 47% of postmenopausal CF. L1-L4 BMD was below the fracture threshold in 8% of postmenopausal AAF and 11% of postmenopausal CF. Serum-25 hydroxyvitamin D (25OHD) was inversely related to age in both othnic groups and lower (P < 0.05) in premenopausal AAF than CF. Twenty-four percent of the AAF and 22% of the CF had serum 25OHD levels of 8 ng/L or less. Serum PTH was directly related to age (r = 0.43; P = 0.003 in AAF and r = 0.55; P = 0.002 in CF), and 25OHD was inversely related to age (r = -0.43; P = 0.003 in AAF and r = -0.65; P < 0.001 in CF). PTH was higher (P < 0.05) in postmenopausal AAF than in CF. Serum testosterone was greater in AAF than in CF (P < 0.05). Serum estradiol was greater in premenopausal AAF than in CF. Serum dehydroepiandrosterone sulfate was inversely related to age (r = 0.42; P = 0.004 in AAF and r = 0.51; P = 0.005 in CF). Serum osteocalcin was related to age in AAF (r = 0.47; P = 0.001), but not in CF. There was also a trend for an increase in urinary dipyridinoline (expressed per 100 mg urinary creatinine) with age (r = 0.31; P = 0.055 in AAF and r = 0.37; P = 0.066 in CF). Both lean and fat mass were major determinants of femoral neck BMD in AAF. Femoral BMD was directly related to body weight and body mass index in both races. Serum 25OHD and dehydroepiandrosterone sulfate approached statistical significance as independent predictors of femoral BMD in AAF. We conclude that in AAF, 1) bone density is higher than in CF, but there is a significant risk of fracture in a substantial number of subjects on the basis of BMD; 2) there is no difference in rates of age-related bone loss compared to those in CF; 3) both lean and fat mass are significant determinants of bone density; 4) serum estradiol and testosterone were higher than those in CF; and 5) aging is associated with increased bone turnover, 25OHD deficiency, and secondary hyperparathyroidism in both races. The absence of a difference in rates of bone loss between AAF and CF despite higher serum levels of PTH is compatible with the concept of a relative skeletal resistance to PTH in AAF.
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Loss of cell adhesion is a critical event in the development of tumour invasiveness and metastases. Although loss of cadherin expression has been demonstrated to be associated with increased invasiveness and metastatic potential in some tumours, others, including renal carcinoma, show no such correlation. The aim of this study was to demonstrate that cell adhesion could be lost in phorbol ester-treated renal epithelial cells and renal tumour cells without loss of A-CAM expression. The model used has been shown previously to mimic changes that occur in the progression of renal carcinoma. We found that A-CAM expression persists on the lateral surfaces of phorbol ester-treated cells even though these cells lose cell-cell adhesion. Similar findings were seen in renal carcinoma cells in culture. We conclude that loss of cell adhesion between tumour cells may other either by loss of cadherins or as a result of loss cadherin function occurring as a consequence of cell transformation.
Calciphylaxis is a rare disease associated with hemodialysis or transplantation, high parathyroid hormone values, and increased serum calcium x phosphate (Ca x P) product. Only four patients on continuous ambulatory peritoneal dialysis have been reported with this condition. We report five cases presenting within a 2-year period with severe calf pain and tenderness with extensive nonulcerating large, hard, and tender subcutaneous plaques in the calves. Calcium deposition was confirmed radiologically and by bone scanning. Four patients were on continuous ambulatory peritoneal dialysis, and the other was not yet on dialysis. High serum Ca x P product was found in three of these patients at onset of the condition. Two patients had normal parathyroid hormone levels at onset. Calcium salts and/or calcitriol had been taken prior to onset in three patients. When presenting in this fashion, the diagnosis can be easily made by the uniqueness of the physical findings in the legs. Our observation suggests that the condition should no longer be considered rare and is not confined to hemodialysis patients. Furthermore, it can occur in predialysis patients.
A genetic model of malignant phase hypertension in rats is described which closely parallels the natural history of untreated human malignant phase hypertension. Although the factors initiating transition from essential hypertension to the accelerated phase in humans remain unknown, we report the characteristics of a genetically determined and reproducible phenotype which was found to result from a cross between hypertensive transgenic Ren-2 rats and normotensive Sprague-Dawley (Edinburgh) rats. Male F1 hybrids developed malignant phase hypertension with a penetrance of 73.5% (95% confidence limits 65.7 to 81.3%) by 100 days of age. Phenotypic features included an accelerated rise in blood pressure, fibrinoid necrosis, activation of the renal renin-angiotensin system and microangiopathic hemolytic anemia. In an analytical cross no significant difference in blood pressure was observed between malignant phase and non-malignant phase animals prior to transition, implying that a factor in addition to hypertension appears necessary for inducing transition to the malignant phase phenotype. Segregation of the malignant phenotype suggested that susceptibility is determined by at most two genetic loci.
The use of high insemination concentration (HIC) for in vitro fertilization (IVF) was compared with intracytoplasmic sperm injection (ICSI) in cases of male factor infertility. Sibling oocytes (n = 252) from 24 patients were used, 123 for HIC and 129 for ICSI. Although the incidence of fertilization was decreased with HIC (48% v. 61%), this treatment was nevertheless a viable option for many patients, especially when ICSI was not available. However, there was a higher incidence of cytoplasmic fragmentation of embryos after HIC compared with ICSI (36% v. 10%, P = 0.003) and the outcome was significantly affected by the severity of teratozoospermia. Using a cut-off of 5% normal forms, the incidence of fertilization with HIC for the group with < 5% normal forms was 37% compared with 72% for the group with > 5% normal forms; there was also a significant decrease in cleavage rate (P = 0.05) and the number of regular embryos (P = 0.005), and an increase in cytoplasmic fragmentation (P = 0.006) in patients with < 5% normal forms. No distinction was made between cases of teratozoospermia when ICSI was used. The present study confirms the value of HIC as a first line treatment for male infertility, as long as ICSI remains significantly more expensive and concerns on safety are mooted. However, the use of sibling oocytes for ICSI is recommended, especially in cases with < 5% normal sperm morphology.
Utilizing real-time computer image analysis, individual spermatozoa were selected using microaspiration. Selection criteria were based on potential hyperactivation motility characteristics; the amplitude of lateral head displacement > 7.5 microns, curvilinear velocity > 70 microns/s and linearity of < 30%. For this pilot study, 16 patients (eight in each group) were recruited. Using subzonal insemination (SUZI), up to five (mean = 4.4 +/- 0.3) spermatozoa selected using computer-image sperm selection (CISS) were micro-injected, or up to 15 (mean = 12.8 +/- 1.3 SD) unselected spermatozoa. In the group which utilized CISS, 28 out of 49 (57%) oocytes were fertilized compared with 13 out of 52 (25%) utilizing conventional SUZI (P < 0.04); polyspermy was 20% (n = 10) and 2% (n = 1) respectively. CISS with SUZI showed increased efficiency in achieving fertilization and is a novel approach to studying individual sperm function in a sperm egg bioassay where gamete ratios are close to unity.
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The objective of this study was to investigate the localization and hormonal regulation of smooth muscle myosin II (SMM II) and alpha smooth muscle actin (alpha SMA) in the baboon uterus, since cytoskeletal proteins are involved in secretory function and morphological transformation. Uterine tissue was obtained from baboons 1) during the menstrual cycle, 2) following steroid treatment of ovariectomized baboons, 3) during pregnancy (Days 14-60 postovulation [PO]), and 4) during simulated pregnancy (Days 18-32 PO). Tissues were processed for immunocytochemical localization of SMM II or alpha SMA with specific polyclonal or monoclonal antibodies, respectively. SMM II stained all smooth muscle cells of blood vessels and myometrium regardless of treatment. Glandular epithelial staining was present only in endometrium obtained during the luteal phase or following estrogen and progesterone treatment. Staining intensity was greater in the basalis than in the functionalis. The number of glands staining positive for SMM II on Days 18-32 of pregnancy and simulated pregnancy was variable. Glandular stain was absent after Day 32 PO. These immunocytochemical data were confirmed by immunoblot analysis of glandular cytosolic extracts. Stromal staining for SMM II was present under the luminal epithelium during simulated pregnancy (Days 18-32), on Day 25 of steroid treatment in the simulated-pregnant controls, and in nonimplantation sites during pregnancy. In contrast, alpha SMA staining was low or absent in all uterine cell types in ovariectomized baboons. Under estrogen-dominated conditions (follicular phase and estrogen treatment), alpha SMA staining was present in smooth muscle cells, and this staining persisted throughout the remaining treatment periods. Glandular epithelial staining for alpha SMA was absent in all treatment groups. However, alpha SMA staining in stromal fibroblasts underneath the luminal epithelium was evident as early as Day 14 of pregnancy and Day 18 of simulated pregnancy. The number of stromal fibroblasts that stained positive increased in the surface region of the functionalis between Days 18 and 32 PO, and the staining extended throughout the upper functionalis region. There was a decrease in the number of positively stained stromal fibroblasts, particularly at the implantation site, between Days 32 and 40 of pregnancy. By Days 50-60 of pregnancy, this staining was almost absent. The induction of alpha SMA in stromal fibroblasts in the functionalis region in pregnant baboons was confirmed by immunoblot analysis of stromal cell cytosol extracts. We conclude that the progesterone-induced glandular expression of SMM II may be involved in uterine secretory function and that alpha SMA expression in stromal fibroblasts during pregnancy and after long-term steroid treatment is associated with the decidualization process.
Familial nephronophthisis is one of the inherited human cystic kidney diseases and is characterized by progressive renal failure. We have investigated abnormalities of cell-matrix interactions using immunocytochemistry and electron microscopy in three renal biopsies from two patients with familial nephronophthisis and compared our findings to those seen in thirty other renal biopsies. We found expression of the alpha 5 integrin fibronectin receptor in all three samples of nephronophthisis but in no other renal diseases. There was also enhanced expression of the alpha 2 integrin in nephronophthisis but this appeared to be a common response to tubular injury. Electron microscopy showed thickening of the tubular basement membrane and a loss of organization of the basal pole of tubular epithelium. We conclude that altered cell-substratum adhesion contributes to the pathogenesis of nephronophthisis.
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We studied paraffin sections of renal biopsies from 7 patients with crescentic glomerulonephritis (CGN) by in situ hybridisation, to detect sites of interleukin-2 receptor (IL-2R) mRNA expression. Frozen sections from a further patient with CGN were studied by immunohistochemistry with a monoclonal antibody to CD25, to detect IL-2R protein. Positive control sections were taken from biopsies of acute cellular renal transplant rejection and negative controls from biopsies of membranous glomerulonephritis. No autoradiographic signal was detected in negative controls. IL-2R mRNA expression was seen in rejected transplants and in sections from 4 to 7 patients with CGN. Expression was seen in cortical interstitial cells, renal tubular epithelial cells, cells within glomerular crescents and in one glomerulus at the margin of Bowman's capsule. Tubular cell expression of IL-2R protein was confirmed by immunohistochemistry. We have confirmed that IL-2R mRNA expression occurs locally within the kidneys in CGN and have identified expression in tubular epithelial cells. The results suggest that local activation of immunocompetent cells occurs in the kidney and may be of significance in the pathogenesis of CGN.
Lead (Pb) poisoning of a pregnant heifer was diagnosed based upon clinical signs (head pressing, blindness, muscle twitching) and a blood lead concentration of 1.73 ppm. Blood and urinary Pb half-lives with CaNa2 EDTA/thiamine therapy were determined to be 2.08 and 1.38 days, respectively. Many cations (Ca, Fe, Zn, Na, Cu), including Pb, were excreted at higher concentrations in urine during therapy. Blood (0.425 ppm) and liver (4.85 ppm) Pb concentrations in the fetus were 71.7% and 84.3% of the same tissue Pb concentrations of the dam, indicating a significant transfer of Pb in utero. Severe polioencephalomalacia was described in the adult, and hepatic lysosomes with metallic electron densities were present in the fetus.