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Biomedical subjects

R Waldherr

Publications and source records attributed to R Waldherr.

At least 109 records · Page 6Linked to original sources
PubMed1993

Proliferation cell nuclear antigen (clone 19A2) correlates with 5-bromo-2-deoxyuridine labelling in human colonic epithelium.

Measurements of cell proliferation can be used as biomarkers of preneoplastic change. In this study, two immunocytochemical methods that measure different components of the cell cycle were compared to assess cell proliferation on biopsy samples from human colonic mucosa. These methods are based on a monoclonal antibody against 5-bromo-2-deoxyuridine (BrdU), which is confined to S phase cells, and a more broad assessment of proliferation based on an antibody against proliferating cell nuclear antigen (PCNA, clone 19A2). In the PCNA assay, only strongly immunostained nuclei were included. The proliferation index was assessed in colonic mucosa from patients with no colonic disorders. Correlation between individual total proliferation indices determined by either method was significant with rs = 0.6 (p < 0.05). The mean proliferation index in the study group was 7.79% using BrdU and 7.64% using PCNA immunocytochemistry. Distribution of labelled cells within crypts was similar with respect to the two methods with a peak at the 18th and the 24th percentile in the case of BrdU and at the 23rd percentile for PCNA. Variance component analysis showed that at least two biopsy specimens should be evaluated per subject to allow a precise individual characterisation. It is concluded that PCNA (19A2) immunocytochemistry may be used as an operational marker of cell proliferation in normal colonic mucosa. A significant correlation and an agreement in the mean proliferation index between PCNA (19A2) and BrdU can only be achieved by a strictly standardised enumeration of labelled cells limited to strongly stained nuclei in the PCNA evaluation.

Adult↗
PubMed1993

Source of kidney determines blood pressure in young renal transplanted rats.

Recipients of a renal graft from adult stroke-prone spontaneously hypertensive rat (SHRSP) but not normotensive Wistar-Kyoto rat (WKY) donors have been shown to develop posttransplantation hypertension. To investigate whether hypertension would also travel with the kidneys from young prehypertensive SHRSP and whether the age-related increase in blood pressure in F1 hybrids (F1H) bred from SHRSP and WKY parents was attenuated by early bilateral nephrectomy and transplantation of a WKY kidney, we transplanted kidneys from 14 male SHRSP and 16 WKY donors aged 35-42 days to young male F1H. Recipients had both native kidneys removed. Fifteen unilaterally nephrectomized nontransplanted F1H served as controls. At the time when kidneys were harvested for transplantation, systolic blood pressures in young SHRSP and WKY donors were not significantly different (114 +/- 5 vs. 113 +/- 3 mmHg). After transplantation, recipients of an SHRSP kidney rapidly developed posttransplantation hypertension with systolic blood pressures above 180 mmHg at 3 mo after transplantation. In contrast, systolic blood pressure in recipients of a WKY kidney rose only slightly with increasing age and remained significantly lower than in non-transplanted controls. Transplanted rats exhibited normal weight gain, and renal function (glomerular filtration rate, renal blood flow) in grafted kidneys was well preserved; plasma renin activity was reduced compared with nontransplanted controls. These data demonstrate that 1) hypertension can be transmitted to normotensive recipients by transplantation of a kidney from young prehypertensive SHRSP donors and 2) the age-related increase in arterial pressure in F1H is attenuated by early bilateral nephrectomy and transplantation of a WKY kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Husbandry↗
PubMed1993

Immunogenetic findings in glomerulonephritis.

In the 19th century, several authors recognized that some renal diseases tend to run in families. Alport pointed to the constellation of nephritic urinary sediment, hearing loss and progression into renal failure. Today this is recognized to result from abnormal basement membrane (BM) collagen synthesis. Recently it has been recognized, however, that other forms of glomerulonephritis may also run in families. In about 10% of patients with glomerulonephritis one or more sibling also suffers from glomerulonephritis. Genetically determined derangements of immune regulation may play a role in the genesis of primary chronic glomerulonephritis. Potentially associated immunogenetic abnormalities include inherited defects of the complement system, increased prevalence of certain HLA-types, altered frequencies of polymorphisms in immunoglobulins and TCR genes and others. This overview summarizes immunogenetic studies performed in patients with glomerulonephritis with special emphasis on patients with mesangial IgA GN.

Complement System Proteins↗
PubMed1992

Serum procollagen peptides and collagen type VI for the assessment of activity and degree of hepatic fibrosis in schistosomiasis and alcoholic liver disease.

Schistosomiasis, in contrast to alcoholic liver disease, leads to presinusoidal hepatic fibrosis, which determines the prognosis of the disease. Because conventional liver function tests and liver biopsy specimens provide little information about the dynamics of the fibrotic process, we measured the serum concentrations of procollagen type III N-propeptide and procollagen type I C-propeptide, believed to mainly reflect collagen synthesis, and procollagen type IV C-propeptide and collagen type VI, two presumptive markers of collagen degradation. Determinations were performed in 15 healthy control subjects, 69 patients with various stages of infection with Schistosoma mansoni/Schistosoma haematobium (28 with an early active infection and no organ involvement, 27 with hepatosplenic involvement and 14 with complications of portal hypertension) and 16 patients with alcoholic cirrhosis. In addition, liver biopsy specimens were obtained from 30 schistosomal patients (18 with hepatosplenic involvement and 12 with complications of portal hypertension for histopathological grading and collagen histochemistry. Procollagen type III N-propeptide was significantly elevated in the three patient groups with schistosomiasis when compared with controls (p less than 0.01). Also, patients with higher histological grading showed significantly higher procollagen type III N-propeptide values (p less than 0.05). In alcoholic patients, procollagen type III N-propeptide was even higher and increased parallel to the severity of the disease, determined by using a combined clinical and laboratory index. Procollagen type I C-propeptide was only elevated in early infection (p less than 0.05) and steadily decreased with disease progression.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

The nephronophthisis complex: clinical and genetic aspects.

Familial juvenile nephronophthisis (NPH) and medullary cystic disease (MCD) are hereditary forms of early-onset chronic renal failure caused by the bilateral formation of cysts at the corticomedullary junction of the kidney. Polyuria, polydipsia, anemia, and growth retardation precede end-stage renal failure. The absence of edema and hypertension frequently leads to a delay in the diagnosis and commencement of therapy. The condition is a major cause of end-stage renal disease (ESRD) in children, accounting for 10%-25% of these patients. About 300 cases of NPH or MCD have been described. Although they are almost indistinguishable clinically and pathologically, the two conditions are separated by a characteristic age of onset (11.5 years in NPH vs. 28.5 years in MCD) and by the mode of inheritance (autosomal recessive in NPH vs. autosomal dominant in MCD). An association of NPH with retinitis pigmentosa is known as the Senior-Løken syndrome (SLS). Hepatic fibrosis, skeletal defects, and central nervous system abnormalities have been described in association with NPH but are typically absent in MCD. Since the pathology of NPH and MCD is similar, the term "nephronophthisis complex" has been introduced to summarize the related diseases. At present, there are no means of identifying heterozygotes, conducting prenatal diagnosis, or screening children in affected families. The histologic changes of NPH are characteristic but not specific for the disease. Cysts of 1-15 mm in diameter, located primarily at the corticomedullary junction, are seen in 70% of the patients. Light microscopy reveals a chronic sclerosing tubulo-interstitial nephropathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Cloning, Molecular↗
PubMed1992

Pathology of the human mesangium in situ.

Mesangial cells play an important role in the development and progression of human glomerular disease. This article summarizes some important aspects of mesangial properties and behaviour in situ. Intrinsic mesangial cells express alpha-smooth muscle actin and are best characterized as myofibroblasts or glomerular pericytes. The main integrin receptor in the mesangium is the alpha 1 beta 1 integrin. The beta 2 and beta 3 integrins have not been detected. Mesangial cells in situ fail to react with many monoclonal antibodies which stain human mesangial cells in culture, including leukocyte activation antigens. Prominent reactions in glomerular disease are mesangial expansion and progressive glomerular sclerosis, which are preceded by or associated with mesangial cell hypertrophy and/or proliferation. Mesangial enlargement is accompanied by an altered integrin expression and an abnormal composition of extracellular mesangial matrix. From the numerous autocrine and paracrine mediators identified in vitro which stimulate or inhibit mesangial cell growth and extracellular matrix synthesis, up to now only a few factors have been shown to be present in selected human glomerulopathies. These include platelet derived growth factors and platelet derived growth factor receptor beta, transforming growth factors beta, interleukin 1 beta, tumor necrosis factor alpha, and interleukin 6. Further identification of such mediators in situ will improve our understanding of pathological glomerular processes, particularly with respect to the multifunctional properties of the mesangial cell.

Glomerular Mesangium↗
PubMed1992

Peritoneal morphology in children treated by continuous ambulatory peritoneal dialysis.

Fifty peritoneal biopsies (PB) from 35 patients with end-stage renal disease, treated by continuous ambulatory peritoneal dialysis (CAPD) and aged 2 months to 18 years, were examined by light microscopy (n = 50) and/or scanning electron microscopy. PB were performed during surgical procedures immediately before the start of, during, or after the cessation of CAPD treatment. PB from 15 children without renal disease undergoing laparatomy were examined similarly. Before the start of CAPD, a scarcity and shortening of the mesothelial microvilli was observed by scanning electron microscopy. During and after CAPD, variable alterations of mesothelium, interstitium and capillaries were found. The mesothelial layer was absent in all 5 PB obtained during episodes of active peritonitis. In patients treated by CAPD for longer than 6 months, mesothelial denudation was observed more frequently (6/11) than in children treated for shorter periods (1/7) (P < 0.08). Fibrosis of the peritoneal membrane was present in about 50% of patients during or after the cessation of CAPD without impairment of peritoneal function. No correlation was found between the presence of fibrosis and the frequency of peritonitis or the duration of CAPD treatment.

Adolescent↗
PubMed1992

Dendritic cells in glomerulonephritis.

Renal biopsies (n = 45) from patients with various forms of glomerulonephritis (GN), comprising mesangial IgA-GN (n = 25), focal glomerular sclerosis (n = 13) and acute GN (n = 7), were examined by double staining immunocytochemistry (APAAP, streptavidin-peroxidase) using unconjugated monoclonal antibodies (Ab) against--(i) the CD1b antigen expressed on dendritic cells (DCs), (ii) the invariant chain (Ii), and (iii) biotin-conjugated Ab against HLA-DR. In normal control kidneys (n = 7) without interstitial inflammation, CD1b-positive DCs were not detected. Glomerular endothelial cells and a few cells in mesangial areas showed double staining with the Ab against HLA-DR in Ii. In GN without active interstitial inflammation (n = 9), CD1b-positive DCs were not found. In biopsies with interstitial inflammation (n = 36) CD1b-positive DCs were found interspersed among other inflammatory cells. In seven of the biopsies showing IgA-GN DCs were seen in the vicinity of those glomeruli that exhibited either crescents or glomerular sclerosis with splitting of Bowman's capsule. In proximal tubular epithelial cells de novo expression of HLA-DR/Ii-chain was only seen when DCs were present. We conclude that in different forms of GN: (i) CD1b-positive DCs play an important role in the development of interstitial inflammation, and (ii) their presence may be related to the de novo coexpression of HLA-DR/Ii in tubular epithelial cells, possibly mediated through the production of interferon gamma and other cytokines.

Antigens↗
PubMed1992

Acquired cystic kidney disease before and after renal transplantation.

To determine the prevalence of acquired cystic kidney disease (ACKD), as reported in adults receiving long-term hemodialysis treatment, we studied 48 pediatric patients (aged 17 +/- 5.1 years) with end-stage renal disease by high-resolution ultrasonography or magnetic resonance imaging or both. Forty patients (83%) had a functioning renal transplant, with a mean transplant survival time of 3.4 years (range, 0.3 to 14.8 years); four patients were treated by hemodialysis and four by peritoneal dialysis. The mean duration of end-stage renal disease was 5.7 +/- 3.8 years. Ultrasonography detected ACKD in 12 (29%) of 42 patients, solitary cysts in 14 patients (33%), and no cysts in 16 patients (38%). In contrast, ACKD was diagnosed in only 3 of 37 patients studied by magnetic resonance imaging. In 31 patients studied by both imaging techniques. ACKD was diagnosed in three patients by magnetic resonance imaging but in 11 by ultrasonography. In patients with ACKD, the duration of end-stage renal disease was significantly longer, but renal (transplant) function was not different from that in patients with solitary cysts or no cysts. One patient with a history of 12 1/2 years of hemodialysis had multiple renal tumors that were diagnosed as renal cell carcinomas after bilateral nephrectomy. These results indicate that young patients with end-stage renal disease should be monitored regularly for the presence of ACKD, preferably by ultrasonography, even after successful renal transplantation.

Adolescent↗
PubMed1992

Renal histology in polycystic kidney disease with incipient and advanced renal failure.

Renal specimens were obtained at surgery or postmortem from patients with autosomal dominant polycystic kidney disease (ADPKD). Patients had either serum creatinine (SCr) below 350 mumol/liter (N = 12) or terminal renal failure (N = 50). Specimens were examined by two independent observers using a carefully validated score system. Mean glomerular diameters were similar in ADPKD patients with early renal failure (176 +/- 38 microns) and in victims of traffic accidents (177 +/- 23 microns), while they were significantly greater in diabetics with comparable renal function (205 +/- 16 microns). Glomerular diameters in ADPKD patients with terminal renal failure (191 +/- 45 microns) and with early renal failure were not significantly different. On average, 29% of glomeruli (17 to 62) were globally sclerosed in early renal failure, and 49% (19 to 93) in terminal renal failure. The proportion of glomeruli with segmental sclerosis was less than 4% in both groups. Marked vascular sclerosis, interstitial fibrosis, and tubular atrophy were present in early renal failure, and even more so in terminal renal failure. Interstitial infiltrates were scarce and consisted mainly of CD4 positive lymphocytes and CD68 positive macrophages. Immunestaining with monoclonal renin antibodies showed an increased juxtaglomerular index and expression of renin by arterioles adjacent to cysts, as well as by cyst wall epithelia. The data show more severe vascular and interstitial, but not glomerular, changes in ADPKD with advanced as compared to early renal failure.

Adult↗
PubMed1992

In situ expression of tumor necrosis factor-alpha, interferon-gamma, and interleukin-2 receptors in renal allograft biopsies.

The production and release of cytokines and their receptors are of critical importance in mediating graft injury. In order to evaluate the expression of cytokines in renal allograft biopsies, we performed immunocytochemical studies to detect activated cells positive for TNF-alpha, IFN-gamma, and IL-2R, using an alkaline phosphatase anti-alkaline phosphatase technique (APAAP). Sixty-one biopsy specimens from renal transplant patients were analyzed and were classified according to both clinical and conventional morphological criteria. There was a significant correlation between the number of positive cells reactive with monoclonal antibodies directed against TNF-alpha, IFN-gamma, and IL-2R and the presence of acute cellular rejection. The mean number of infiltrating cells (cells/mm2) positive for TNF-alpha (9.2 +/- 1.1), IFN-gamma (6.7 +/- 1.7), and IL-2R (31.2 +/- 4.8) was significantly greater in acute cellular rejection episodes compared with nonrejecting kidneys (0.9 +/- 0.2, 1.2 +/- 0.4, and 8.8 +/- 2.9 positive cells/mm2 for TNF-alpha, IFN-gamma, and IL-2R, respectively). No significant expression of these cytokines was found in the majority of biopsies with chronic rejection. In two cases, in which acute cellular rejection was not sustained on clinical grounds but was diagnosed on histology, the expression of TNF-alpha, IFN-gamma, and IL-2R was similar to that observed in typical cellular rejection. We conclude that TNF-alpha, IFN-gamma, and IL-2R are markedly expressed by activated mononuclear infiltrating cells in acute cellular rejection, and that these cytokines play an important role in allograft rejection. The immunocytochemical evaluation of cytokine expression is a simple and rapid method that is helpful in differentiating acute cellular rejection from other causes of graft disfunction.

Adolescent↗
PubMed1992

Human gastric alcohol dehydrogenase: in vitro characteristics and effect of cimetidine.

The presence of at least two types of alcohol dehydrogenase has been demonstrated in surgical specimens from the human stomach. One isoenzyme has a Km of approximately 1-2 mM for ethanol comparable to that of class I alcohol dehydrogenase isoenzyme as defined for the liver. This isoenzyme can also be detected by immunohistology using a polyclonal rabbit antibody against human liver class I alcohol dehydrogenase. The other isoenzyme of alcohol dehydrogenase has a much lower affinity to ethanol (greater than 300 mM), but with activities that become significant at ethanol concentrations of more than 100 mM commonly present in the human stomach. Cimetidine was found to be a noncompetitive inhibitor of gastric alcohol dehydrogenase at concentrations as low as 1 mM in vitro. Since the human gastric alcohol dehydrogenase is responsible for the first-pass metabolism of ethanol, its inhibition by cimetidine may explain the reduced first-pass metabolism of alcohol which is associated with elevated ethanol blood concentrations seen after cimetidine therapy.

Aged↗