A comparison of the anti-diabetic potential of d-ribose-l-cysteine with insulin, and oral hypoglycaemic agents on pregnant rats.

Over 18% of pregnant women are affected by diabetes mellitus (DM) and Insulin has been the commonest drug used in its treatment. There are reports of noncompliance to insulin due to trypanophobia, with suggestions for the use of oral hypoglycaemic agents (OHAs). However, the opposing views about the benefits and risk of oral hypoglycaemic agents (OHAs) warrant a continuous search for an alternative regimen. Therefore, this study is aimed at comparing the antidiabetic effects of d-ribose-l-cysteine (riboceine) with vildagliptin, glibenclamide, metformin, glipizide and insulin in diabetes in pregnancy. Forty (40) female Sprague-Dawley (SD) rats were mated with twenty (20) male SD rats. Diabetes was induced by streptozotocin and the female SD rats were divided into 8 groups of five (5) rats each. The animals were administered either of the OHAs vildagliptin, glibenclamide, metformin, glipizide and riboceine for a period of 19 gestational days. The results showed that streptozotocin (STZ) significantly (p < 0.05) decreased the weights of the animals, increased malondialdehyde, blood glucose levels and altered reproductive hormones. These effects of STZ were better ameliorated in animals that received insulin and riboceine compared to the other OHAs. While progesterone levels were significantly (p < 0.05) higher in animals that received riboceine compared to insulin. Glibenclamide increased (p < 0.05) foetal weights compared to non-diabetic animals. In conclusion, glibenclamide may be a threat to mother`s life in the management of diabetes in pregnancy however, riboceine as well as vildagliptin, metformin and glipizide are effective oral hypoglycaemic agents which could serve as a potent adjuvant comparable to insulin in the management of diabetes during gestation.

Key Matrix Proteins Within the Pancreatic Islet Basement Membrane Are Differentially Digested During Human Islet Isolation.

Clinical islet transplantation achieves insulin independence in selected patients, yet current methods for extracting islets from their surrounding pancreatic matrix are suboptimal. The islet basement membrane (BM) influences islet function and survival and is a critical marker of islet integrity following rodent islet isolation. No studies have investigated the impact of islet isolation on BM integrity in human islets, which have a unique duplex structure. To address this, samples were taken from 27 clinical human islet isolations (donor age 41-59, BMI 26-38, cold ischemic time < 10 h). Collagen IV, pan-laminin, perlecan and laminin-α5 in the islet BM were significantly digested by enzyme treatment. In isolated islets, laminin-α5 (found in both layers of the duplex BM) and perlecan were lost entirely, with no restoration evident during culture. Collagen IV and pan-laminin were present in the disorganized BM of isolated islets, yet a significant reduction in pan-laminin was seen during the initial 24 h culture period. Islet cytotoxicity increased during culture. Therefore, the human islet BM is substantially disrupted during the islet isolation procedure. Islet function and survival may be compromised as a consequence of an incomplete islet BM, which has implications for islet survival and transplanted graft longevity.

Secondary solid cancer screening following hematopoietic cell transplantation.

Hematopoietic stem cell transplant (HCT) recipients have a substantial risk of developing secondary solid cancers, particularly beyond 5 years after HCT and without reaching a plateau overtime. A working group was established through the Center for International Blood and Marrow Transplant Research and the European Group for Blood and Marrow Transplantation with the goal to facilitate implementation of cancer screening appropriate to HCT recipients. The working group reviewed guidelines and methods for cancer screening applicable to the general population and reviewed the incidence and risk factors for secondary cancers after HCT. A consensus approach was used to establish recommendations for individual secondary cancers. The most common sites include oral cavity, skin, breast and thyroid. Risks of cancers are increased after HCT compared with the general population in skin, thyroid, oral cavity, esophagus, liver, nervous system, bone and connective tissues. Myeloablative TBI, young age at HCT, chronic GVHD and prolonged immunosuppressive treatment beyond 24 months were well-documented risk factors for many types of secondary cancers. All HCT recipients should be advised of the risks of secondary cancers annually and encouraged to undergo recommended screening based on their predisposition. Here we propose guidelines to help clinicians in providing screening and preventive care for secondary cancers among HCT recipients.

Staining characteristics of Lonchocarpus cyanescens leaf extract on the testis of Sprague-Dawley rats.

The use of nonallergic, nontoxic, and eco-friendly natural dyes has become a matter of significant importance due to increased environmental awareness on the need to avoid hazardous synthetic dyes. This study was to determine the staining properties of the dye extract of Lonchocarpus cyanescens on histomorphology of the testis. Freshly cut leaves of L. cyanescens obtained from Akpan Ifia Inan village in Ikono local government area of Akwa Ibom state (latitude 5° 10' 12″ N; longitude 7° 48' 0″ E) were put into a plastic jar and boiling water was poured to cover the leaves. It was covered and left for an hour. The liquid was strained and potassium hydroxide was added to the dye water mixture to reach a pH of 9. A whisk was used to mix air into the liquid, and the mixuture was then allowed to sit until the blue indigo had settled to the bottom of the container. The dye was diluted with 70% ethanol to a concentration of 0.1 g/mL and was used to stain sections of testes. Its potential for use as a counterstain was also investigated. The testes sections were stained in shades of blue. The dye overshadowed the colors of haematoxylin and eosin. Preliminary phytochemical screening of L. cyanescens revealed that it contains alkaloids, saponins, flavonoids, and tannins.

Contrasting effects of A1 and A2b adenosine receptors on adipogenesis.

BACKGROUND: Adenosine mediates its actions through four G protein-coupled receptors, A1, A2a, A2b and A3. The A1 receptor (A1R) is dominant in adipocytes where it mediates many actions that include inhibition of lipolysis, stimulation of leptin secretion and protection against obesity-related insulin resistance. OBJECTIVE: The objective of this study is to investigate whether induced expression of A1Rs stimulates adipogenesis, or whether A1R expression is a consequence of cells having an adipocyte phenotype. METHODOLOGY: Human A1R and A2b receptors (A2bRs) were stably transfected into a murine osteoblast precursor cell line, 7F2. Adipogenesis was determined by lipid accumulation and expression of adipocyte and osteoblast marker molecules. Adenosine receptor expression and activation of associated signal molecules were also evaluated as 7F2 cells were induced to differentiate to adipocytes. RESULTS: 7F2 cells transfected with the A1R showed increased adipocyte marker mRNA expression; lipoprotein lipase and glycerol-3-phosphate dehydrogenase were both upregulated, whereas the osteoblast marker alkaline phosphatase (ALP) was downregulated. When cultured in adipocyte differentiating media, such cells also showed increased adipogenesis as judged by lipid accumulation. Conversely, A2bR transfection stimulated osteocalcin and ALP expression, and in addition, adipogenesis was inhibited in the presence of adipocyte differentiation media. Adipogenic differentiation of naive 7F2 cells also resulted in increased expression of the A1R and reduced or modified expression of the A2a and A2bR. The loss of A2 receptors after adipogenic differentiation was accompanied by a loss of cyclic adenosine monophosphate and ERK1/2 signalling. CONCLUSION: These data show that expression of A1Rs induced adipocyte differentiation, whereas A2bR expression inhibited adipogenesis and stimulated an osteoblastic phenotype. These data suggest that targeting A1 and A2bR could be considered in the management of obesity and diabetes. Targeting adenosine signal pathways may be useful in treatment strategies for diseases in which there is an imbalance between osteoblasts and adipocytes.

Design of a self-cleaning thermoresponsive nanocomposite hydrogel membrane for implantable biosensors.

Following implantation of a biosensor, adhesion of proteins and cells and eventual fibrous encapsulation will limit analyte diffusion and impair sensor performance. A thermoresponsive nanocomposite hydrogel was developed as a self-cleaning biosensor membrane to minimize the effect of the host response and its utility for an optical glucose sensor, demonstrated here. It was previously reported that thermoresponsive nanocomposite hydrogels prepared from photopolymerization of an aqueous solution of N-isopropylacrylamide (NIPAAm) and polysiloxane colloidal nanoparticles released adhered cells with thermal cycling. However, poly(N-isopropylacrylamide) hydrogels exhibit a volume phase transition temperature (VPTT) of approximately 33-34 degrees C, which is below body temperature. Thus, the hydrogel would be in a collapsed state in vivo, which would ultimately limit diffusion of the target analyte (e.g., glucose) to the encapsulated sensor. In this study, the VPTT of the nanocomposite hydrogel was increased by introducing N-vinylpyrrolidone (NVP) as a comonomer, so that the hydrogel was in the swollen state in vivo. This thermoresponsive nanocomposite hydrogel was prepared by the photopolymerization of an aqueous solution of NIPAAm, NVP, and polysiloxane colloidal nanoparticles. In addition to a VPTT a few degrees above body temperature, the hydrogel also exhibited good mechanical strength, glucose diffusion, and in vitro cell release upon thermal cycling. Thus, this nanocomposite hydrogel may be useful as a biosensor membrane to minimize biofouling and extend the lifetime and efficiency of implantable glucose sensors and other biosensors.

Effect of the juice of lime (Citrus aurantifolia) on estrous cycle and ovulation of Sprague-Dawley rats.

OBJECTIVE: To determine the effect of lime juice on the estrous cycle and ovulation of cyclic female rats. METHODS: Twenty-five adult female Sprague-Dawley rats were used. The study was divided into 2 experiments (I and II). In experiment I, 15 rats were randomly subclassified into 3 groups (Ia, Ib, and Ic) of 5 rats each. The estrous cycles of the rats were studied for the first 16 days to establish cyclicity, after which lime juice was administered by gastric gavage for the next 24 days. Rats in group Ia received 1 mL of undiluted lime juice, rats in group Ib received 1 mL of 50% diluted lime juice, and rats in group Ic (control animals) received only distilled water. In experiment II, 10 female rats were used and were categorized into 2 groups (IIa and IIb), with 5 rats in each group. Rats in group IIa received 1 mL of undiluted lime juice during the morning of proestrus, and those in group IIb received only distilled water on the day of proestrus. The rats were killed the next day with use of chloroform anesthesia. The upper parts of the oviducts were excised and examined under the light microscope for assessment of the number of ova shed. RESULTS: There was an irregular pattern in all phases of the estrous cycle of 100% of the rats given undiluted lime juice and in 80% of those given 50% diluted lime juice. There was a significant (P = .001) reduction in the number of ova shed in rats administered undiluted lime juice in comparison with the control animals. Ovulation was partially blocked, as shown by the reduced number of ova observed in the oviducts from the rats given undiluted lime juice (5.10 +/- 2.37) in comparison with the control rats (12.70 +/- 1.14). CONCLUSION: In rats, lime juice causes irregularity of the estrous cycle, partially blocks ovulation, and may possibly compromise fertility.

Antiovulatory and anti-implantation potential of the methanolic extract of seeds of Abrus precatorius in the rat.

OBJECTIVE: To investigate the effect of the methanolic extract of seeds of Abrus precatorius on the estrous cycle, ovulation, and implantation of fetuses in Sprague-Dawley rats. METHODS: Cyclic female rats were randomly classified into 4 groups (A through D). Treated rats in group A had daily vaginal smears for a total of 64 consecutive days while being fed A precatorius extract for the first 32 of those days. Treated rats in group B received a single oral dose of the extract on the day of proestrus and were killed the following morning so that shed ova could be counted. Treated rats in group C received A precatorius extract from postcoital day 1 to 10 and were killed on day 12 to assess for anti-implantation effect, whereas the treated dams in group D received the extract from the 6th to the 19th day of gestation. The control animals in all 4 groups received an equal volume of distilled water. RESULTS: The methanolic extract of A precatorius caused a reversible disruption in the estrous cycle of the regularly cyclic rats and completely blocked ovulation in all the treated rats. Despite successful mating of the female rats with male rats of proven fertility, uterine dissection on postcoital day 12 revealed neither implantation nor resorption sites in all the animals treated with A precatorius. The extract of A precatorius caused a decrease in mean body weight, mean crown-rump length, and mean tail length of fetuses of the treated rats. CONCLUSION: There is a need to continue the search for new antifertility agents that have minimal side effects and widespread acceptability in addition to being reversible, affordable, and accessible. In this study, methanolic extract of A precatorius seeds caused reversible alterations in the estrous cycle pattern and completely blocked ovulation in Sprague-Dawley rats. In addition, the extract demonstrated anti-implantation activity and the potential to affect gross fetal morphometry in rats.

The development and regression of deciduosarcomas and other lesions caused by estrogens and progestins in rabbits.

A series of experiments were conducted to study the histopathological effects of a combination of exogenous estrogens and progestins in mature rabbits. Estradiol (14-45 microg/day) and levonorgestrel (30-233 microg/day) were administered by intravaginal or subdermal Silastic devices for various time intervals to study the development of lesions with time and to determine if lesions regressed following withdrawal of the steroids. The origin of splenic decidual tumors (primary or metastasis from the uterus) was determined by administering the same steroid combination to castrated male rabbits. It was determined that uterine decidualization is present after 7 days of steroid treatment and that neoplasms of decidual cells may appear in the uterus after only 30 days of steroid administration. Decidual changes were observed frequently in uterine arteries, often concurrent with infarct-like areas of necrosis of the uterine wall. Withdrawal of contraceptive steroids for 14-120 days after 60 days' administration resulted in atrophy and disappearance of decidual cells and decidual tumors. Decidual neoplasms developed in the spleen of all castrated male rabbits given subdermal steroids, demonstrating that these tumors can arise as primary neoplasms of the spleen. The foregoing lesions appear to be peculiar to the rabbit and, together with previous data, suggest the rabbit to be a poor model for evaluating the effects of contraceptive steroids in other species.

Perindopril ameliorates glomerular and renal tubulointerstitial injury in the SHR/N-corpulent rat.

We compared the effects of long-term treatment with the angiotensin-converting enzyme inhibitor perindopril and triple therapy (hydrochlorothiazide, reserpine, and hydralazine) on the metabolic and renal features in the SHR/N-corpulent (cp) rat, a genetic model of non-insulin-dependent diabetes mellitus and hypertension. Obese male SHR/N-cp rats (4 to 6 weeks old) were fed a 54% carbohydrate diet containing 18% sucrose and 36% starch. After 2 months on the diet, rats were assigned to one of three groups: one group (n=8) received perindopril (PE); the second group (n=8) received triple therapy (TT); and the third group (n=8) did not receive therapy. Treatment was maintained for 3 to 4 months. Body weight, food intake, and fasting levels of serum glucose and insulin did not differ among the three groups. Control rats exhibited progressive proteinuria in parallel with the rise in systolic blood pressure (SBP). Both PE and TT equally lowered SBP to normal levels and reduced proteinuria in treated rats. However, the reduction of proteinuria was greater and more sustained with PE than with TT (P<.05), whereas the effect of TT on proteinuria was delayed. Plasma renin activity was increased in PE and TT rats compared with control rats (P<.02). Semiquantitative analysis of renal lesions showed that the percentage of glomeruli with mesangial expansion and sclerosis and the tubulointerstitial score (an index of severity of tubulointerstitial lesions, namely tubular atrophy, inflammatory cellular infiltrates, and interstitial fibrosis) was reduced in both PE and TT rats. However, the reduction of glomerulosclerosis and tubulointerstitial lesions was greater in PE than in TT rats (P<.01). The percentage of glomerular sclerosis was positively correlated with the severity score of tubulointerstitial lesions (r=.60, P<.01). We conclude that PE is more effective than TT in halting the progression of proteinuria in the SHR/N-cp rat with non-insulin-dependent diabetes mellitus and hypertension. The antiproteinuric effect of PE is associated with significant reduction in glomerulosclerosis and tubulointerstitial lesions, independent of the effect of treating hypertension.

Renal TGF-beta in HIV-associated kidney diseases.

Human immunodeficiency virus (HIV)-1 infection may be complicated by progressive renal glomerular disease, including focal segmental glomerulosclerosis (FSGS) and proliferative glomerulonephritis. We examined renal tissue from 71 patients, including biopsies and autopsies from patients in the presence and absence of HIV-1 infection. We assessed the extent of TGF-beta, interstitial fibrosis, and interstitial CD45-positive cellular infiltrate using immunohistochemistry. Extracellular TGF-beta 1/beta 3 was largely confined to the renal interstitium, with the highest scores in HIV-seropositive renal disease and crescentic nephritis. Among all biopsies, the TGF-beta 1/beta 3 score correlated with the fibrosis score (r = 0.79, P < 0.0001) and with the CD45 score (r = 0.60, P < 0.0001). Biopsies from HIV-infected patients, taken together, showed marginally more TGF-beta 1/beta 3 compared to biopsies from HIV-uninfected patients (P = 0.05); similarly, HIV-associated FSGS showed marginally more TGF-beta 1/beta 3 compared to FSGS biopsies obtained from HIV-uninfected patients (P = 0.05). Intracellular TGF-beta 1 and TGF-beta 3 were both expressed by renal tubular epithelial cells and in extraglomerular crescents, whereas TGF-beta 3 was also present within interstitial mononuclear cells and eosinophils, and, exclusively in HIV-infected patients, within glomerular cells. In conclusion, TGF-beta expression was increased in several progressive glomerular diseases, and was particularly but not uniquely elevated in HIV-associated renal diseases.

Apoptosis in human immunodeficiency virus-associated nephropathy.

Focal segmental glomerulosclerosis associated with human immunodeficiency virus nephropathy (HIVFGS) involves glomeruli, tubules, and interstitium. Its pathogenesis is unknown, but HIV peptides may be critical in its development. Human immunodeficiency virus peptides and peptide-antibody complexes are immunomodulatory, and are associated with apoptosis in lymphoid cells. To determine whether apoptosis is present in HIVFGS, renal biopsy specimens of eight patients with HIVFGS were compared with those of 10 patients with idiopathic focal glomerulosclerosis (FGS) using the Apoptag kit (Oncor, Gaithersburg, MD), which detects single cell apoptosis in formalin-fixed tissue by staining 3' nucleosome fragments with digoxigenin-labeled nucleotides after terminal deoxynucleotidyl transferase enzyme treatment. Apoptosis was scored per glomerulus, in total renal tissue sectioned, and in tubules and interstitium per square millimeter using a computerized digital image analyzer. There was no difference between the number of apoptotic cells per glomerulus or per square millimeter of interstitium in patients with FGS and HIVFGS. There were greater numbers of tubular apoptotic cells per square millimeter (2.1 +/- 0.9 v 0.15 +/- 0.08; P = 0.03) in HIVFGS compared with idiopathic FGS. The difference between apoptotic cells per total square millimeter of renal tissue (2.8 +/- 1.2 v 0.7 +/- 0.3) approached significance (P = 0.066). Apoptosis may be associated with the pathogenesis of HIV nephropathy and may be an important determinant of the tubular disease in HIVFGS.

Development and characteristics of a new strain of obese hyperinsulinemic and hyperlipidemic Dahl salt-sensitive rat. The Dahl salt-sensitive/NIH-corpulent rat.

A new congenic rat strain, the Dahl salt-sensitive/NIH-corpulent (DSS/N-cp) rat, has been developed to study the role of obesity and type of dietary carbohydrate in the development of hypertension and its complications. Three groups (n = 6) of young male obese and lean DSS/N-cp rats were fed diets containing either 54% sucrose, 18% sucrose plus 36% starch, or 54% starch, with 0.1% dietary sodium for 12 weeks. Regardless of the diet, obese and lean rats showed mildly elevated systolic blood pressure (SBP), being significantly higher in obese than in lean rats (SBP 156 +/- 5 mm Hg v 141 +/- 3 mm Hg, P < .05). However, SBP was not different between the three diet groups. Levels of serum insulin, triglyceride, and cholesterol as well as urinary protein excretion were significantly higher in obese than in lean rats. Obese rats fed the sucrose diets as compared to the starch diet, had higher serum insulin and lipid levels, but had lower body weights and higher serum creatinine levels. Histopathologic examination of tissues from different organs revealed a vasculopathy seen almost exclusively in obese rats fed the sucrose diets. Vascular lesions were characterized by subintimal fibrin deposition, fibrinoid necrosis, and cell proliferation with "onion skinning" in small arteries and arterioles of kidneys, intestine, pancreas, and testes.(ABSTRACT TRUNCATED AT 250 WORDS)

Diabetic glomerulopathy in the SHR/N-corpulent rat: role of dietary carbohydrate in a model of NIDDM.

We evaluated the course of diabetes and nephropathy in the SHR/N-cp (corpulent) rat characterized by genetic obesity, non-insulin-dependent diabetes (NIDDM), and hypertension, and examined whether the nephropathy in this model is influenced by the type of carbohydrate intake. Two groups of obese and lean SHR/N-cp rats were fed diets containing 54% carbohydrate, as either sucrose or starch for 3 months (group I) and 9 months (group II). After 3 months on either diet, group I obese rats had higher 2-h response serum glucose levels and urinary glucose excretion than lean rats. Sucrose feeding was associated with greater proteinuria and a higher percentage of abnormal glomeruli in obese rats. Morphometric evaluation of glomeruli (by computerized image analysis) showed greater mean renal corpuscular volume and mesangial fraction in obese than in lean rats fed similar diets. Mean renal corpuscular volume and mesangial fraction were also greater in sucrose-fed obese rats than in starch-fed obese rats. After 9 months, group II obese rats had substantial reductions in serum and urine glucose levels but they were still hyperinsulinaemic and showed more proteinuria than lean rats and a higher percentage of sclerotic glomeruli compared with group I obese rats. At this time, mean mesangial fraction but not renal corpuscular volume was still higher in obese than in lean rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Macrophages in human immunodeficiency virus-associated kidney diseases.

Human immunodeficiency virus (HIV)-associated nephropathies are characterized by renal immune cell interstitial infiltration in patients with peripheral T-cell depletion. Since interstitial inflammation may mediate cytokine-induced fibrosis, we evaluated the immune cell population in the interstitium and glomeruli in renal biopsy tissue from 10 HIV-infected patients with focal segmental glomerulosclerosis (HIVFGS), staining renal biopsy specimens for UCHL-1 (a T-cell marker), OPD4 (predominantly a T helper-cell marker), PG-M1 (a macrophage marker), and L26 (a B-cell marker), and comparing them with renal tissue specimens from patients with HIV-associated immune complex glomerulonephritis (ICD) and from uninfected patients with FGS. Five fields comprising 0.2 mm2 were examined at a magnification of x400, a total area of 1 mm2. Total immune cells were estimated as the sum of UCHL-1, L-26, and PG-M1 cells. The T helper to suppressor (H/S) ratio was estimated as OPD4/(UCHL-1 - OPD4) lymphocytes. Tubular interstitial infiltrate was variable but dense in the majority of the infected biopsies, and was mild to moderate in all uninfected cases. The proportion of interstitial macrophages was greater in biopsy specimens from patients with HIVFGS than in those with HIVICD. In contrast, there was a greater percentage of B cells in the infiltrate in HIVICD compared with HIVFGS. Although there were fewer immune cells in whole glomeruli compared with 1 mm2 interstitium, macrophages were the predominant cells in glomeruli. B lymphocytes were generally absent in glomeruli in infected tissue, a pattern similar to uninfected tissue. The blood H/S ratio in HIV-infected patients was 0.2 +/- 0.03.(ABSTRACT TRUNCATED AT 250 WORDS)

Membranoproliferative glomerulonephritis in a patient treated with interferon-alpha for human immunodeficiency virus infection.

Several renal pathologic entities have been reported to be associated with human immunodeficiency virus (HIV) infection. The most common is focal glomerulosclerosis, but several different types of glomerulonephritis have been observed in patients with HIV infection and the acquired immunodeficiency syndrome. The mechanisms involved in the pathogenesis of the kidney disease remain obscure. We studied an HIV-infected patient treated with interferon-alpha who had developed proteinuria and membranoproliferative glomerulonephritis to determine whether the renal disease was associated with HIV infection or with chemotherapy. Circulating HIV antibodies were assessed by enzyme-linked immunosorbent assay; circulating immune complexes (CICs) were measured by C'1q assay and isolated by polyethylene glycol precipitation, then subjected to gel electrophoresis and immunochemical analysis. Renal biopsy tissue underwent acid elution, and the eluates were analyzed similarly. In addition the eluted antibody and the antibody from the CIC were assessed by immunodiffusion with eluate and immune complex antigens. A single CIC was detected, which was composed of an immunoglobulin G antibody complexed to a 26-kd protein antigen that was shown to be interferon-alpha. Eluate from the renal biopsy tissue demonstrated identical material, which cross-reacted with the components of the isolated CIC. Immune complex renal diseases, such as membranoproliferative glomerulonephritis, may be related to biologic response modifying agents in patients with HIV infection. The relative roles of their biologic response modification and the disordered immunoregulation seen in such patients in the pathogenesis of the renal disease is unclear. Renal biopsy is necessary to assess the etiology of the renal disease in HIV-infected patients.

A comparison of the usefulness of electron microscopy and immunohistochemistry. One laboratory's experience.

As a quality assurance measure, the usefulness of transmission electron microscopy (EM) and immunohistochemistry (IHC) in our surgical pathology laboratory was compared. The surgical pathology reports from 150 consecutive neoplasms that were examined by both EM and IHC were reviewed. Based on the reported clinical histories, final diagnoses, light microscopy results, and the findings by EM or IHC, the contributions of EM and IHC were classified as "helpful" or "not helpful" for each specimen. Electron microscopy was helpful (92%) more often than was IHC (73%). Electron microscopy was most useful in further classifying poorly differentiated carcinomas, while IHC was particularly useful in classifying poorly differentiated neoplasms. Electron microscopy and IHC were of limited value in identifying the origin of metastatic carcinomas of an uncertain primary. All cases determined to be "not helpful" by either modality were further analyzed to establish a reason for the lack of information provided in each case. This analysis demonstrated a need for improved technical quality and ordering patterns of immunohistochemical stains in our laboratory.

S-100 protein-negative malignant melanoma: fact or fiction? A light-microscopic and immunohistochemical study.

S-100 protein is considered a characteristic immunohistochemical marker for all nevomelanocytic lesions, in which it is expected to be present consistently. We reviewed 17 cases of malignant melanomas that previously tested negative for S-100 protein. They were reevaluated by light microscopy, a broad panel of immunohistochemical reagents including monoclonal and polyclonal antibodies to S-100 protein, and electron microscopy. On reexamination, five of the 17 cases were reclassified as non-melanoma tumors, and eight of the 17 cases were found to be positive for S-100 protein (six with monoclonal and eight with polyclonal antibodies) and HMB-45 antigen, consistent with melanoma. The remaining four cases repeatedly tested negative for S-100 protein despite various antigen enhancement methods, but they were positive for HMB-45 antigen and contained premelanosomes or melanosome-like structures by electron microscopy. Two of these repeatedly S-100 negative melanomas were acrally located; although the numbers are small, a possible relationship to a specific anatomic location cannot be excluded. These findings suggest that in a small subset of melanomas S-100 protein is either not fully expressed or is below the level that can be detected by routine immunohistochemistry. We also conclude that in the majority of the initially S-100-negative cases of melanomas, the misdiagnosis may occur due to the use of an incomplete immunohistochemical panel, technical reasons, or the inherent variability of tissue expression of S-100 protein.

HIV-associated immune-mediated renal disease.

Although focal glomerulosclerosis is the most common renal disease, other proliferative glomerulonephritides are encountered in HIV-infected patients. We studied four HIV-infected patients with renal insufficiency, proteinuria, and proliferative glomerulonephritis, consistent with immune-mediated disease, to investigate the role of the virus and immune complexes in the pathogenesis of the nephropathy. Circulating immune complexes (CICs) and HIV-reactive antibodies were measured and characterized in each patient. Renal biopsy tissue was acid eluted, and the eluate analyzed. DNA extracted from biopsies was subjected to the polymerase chain reaction (PCR) to detect HIV genome. CICs were detected in each patient: an IgA-p24 HIV antigen complex and an IgG antibody-gp 120 HIV antigen complex in two patients; two patients had an IgG-p24 HIV antigen complex. Identical complexes were eluted from renal tissue in the first three patients; p24 HIV antigen, and complement from the fourth. The eluted antibodies reacted with the HIV antigens from the isolated CICs. Direct immunofluorescence for viral antigen in the eluted glomerular tissue revealed HIV antigens; PCR confirmed the presence of gag genome in all four biopsies. We conclude both circulating and in-situ HIV antigen-specific immune complexes may be associated with glomerulonephritis in HIV infected patients. Viral incorporation into renal tissue may be important in the pathogenesis of HIV-associated renal disease.