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M Schreiber

Publications and source records attributed to M Schreiber.

At least 145 records · Page 8Linked to original sources
PubMed1993

Prevalence and long-term outcome of glomerulonephritis in renal allografts.

We report long-term results over 10 years in patients developing glomerulonephritis after renal transplantation. The prevalence rate of glomerulonephritis was 6.2% in 785 renal transplants involving 697 patients with end-stage renal disease. This rate was 14% in patients undergoing biopsy of their grafts because of malfunction. The rate was 15% in patients diagnosed as having glomerulonephritis of any cause prior to transplantation. Membranous, focal sclerosing, and IgA glomerulonephritis were the most common histologic diagnoses. Documented histologic recurrence occurred in only 1% of patients with poor, biopsy-proven glomerulonephritis of their native kidneys. Patients with focal sclerosing glomerulonephritis had the greatest risk from recurrence. De novo glomerulonephritis was most likely to be membranous in character. The graft survival rate of patients with glomerulonephritis was not distinguishable from that of patients showing rejection; both were 45% at 60 months and 33% versus 11%, respectively, at 120 months (P = NS); the graft survival rate in patients without rejection was 76% at 120 months. Thus, glomerulonephritis is responsible for approximately 14% of renal graft malfunction. Glomerulonephritis has a prognosis similar to chronic rejection. Finally, glomerulonephritis as specific histologic recurrence is unusual. Patients with glomerulonephritis should not be discouraged from undergoing transplantation because of putative risks related to recurrence.

Adolescent↗
PubMed1993

Antioxidants in brain and the effect of hypoxia.

In the first part of our experiments we investigated the ascorbic acid content in five areas of the brain in 11 age groups of rats aged 1 to 90 postnatal days. In the area of the olfactory lobe the values vary within the range of 2.9-4.5 mmol/kg fresh weight, with a significant drop on the 21st, 35th and 90th day. In the cerebral cortex the scatter of values was similar with a significant drop on the 21st and 90th day. From the hippocampal area varying values were obtained, the drop on the 5th, 12th, 15th, 21st, 35th and 90th day being significant. The curve of the ascorbic acid content in the area of the vermis cerebelli has the typical shape of a wave. The initial drop is followed by a rise with the maximum on the 18th day. A significant drop was observed on the 5th, 7th and 90th day, a significant rise on the 12th, 15th, 18th and 21st day. In the area of the medulla oblongata the lowest ascorbic acid values in our experiment were recorded. A significant drop was observed on the 5th, 21 st, 35th and 90th day, a significant rise on the 18th day. All significances are referred to one-day old rats. In the second part of our experiments we studied the influence of acute and chronic hypoxia on the ascorbic acid content in liver, adrenal, plasma, cerebrospinal fluid and brain in 18-day-old rats. Due to acute hypoxia a significant decrease in ascorbic acid concentration in the adrenal occurred. Its levels in plasma and cerebrospinal fluid increased significantly compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1993

Human Kupffer cells infected with HIV-1 in vivo.

Blood monocytes as well as cells of the macrophage-phagocytic system in several tissues are targets for HIV-1 in vivo and in vitro. However, the data on HIV-1 infection of liver macrophages/Kupffer cells (KCs), which make up the main pool of fixed-tissue macrophages, is controversial. We therefore studied HIV-1 infection of KCs in vivo. Blood and liver tissue was obtained from seven AIDS patients shortly after death. Liver tissue was minced before processing. Cell suspensions were further purified by density gradient centrifugation, stained with anti-CD14 (blood monocytes) or anti-macrophage 25F9 (KCs), and separated by fluorescence-activated cell sorting (FACS). These highly purified cell populations were then analyzed for HIV-1 proviral DNA by the polymerase chain reaction (PCR). By performing PCR on FACS-purified cell populations, we could show that both KCs and peripheral blood monocytes were HIV-1-infected in 3 of 7 patients. KCs harbored HIV-1 proviral DNA only if peripheral blood monocytes were infected. These data show that KCs of the liver are infected with HIV-1 in vivo.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Estimating glucose absorption in peritoneal dialysis using peritoneal equilibration tests.

To determine peritoneal dialysis patients' dietary energy requirements, the glucose absorbed from the dialysate needs to be quantified. The currently accepted method of estimating glucose absorption is based on the average glucose absorption of 7 continuous ambulatory peritoneal dialysis (CAPD) patients (Grodstein, 1981). Peritoneal equilibration test curves have shown that modality and transport characteristics affect glucose absorption. To test a more accurate procedure for estimating glucose absorption, we compared two different methods of determining the actual glucose absorption: Grodstein formula: (11.3 xa-10.9) liters of dialysate, where xa is the average glucose concentration, and the D/D0 formula: (1-D/D0)xi, where xi is the initial glucose instilled, using 4-hour D/D0 for CAPD and dwell time D/D0 for automated peritoneal dialysis (APD). Twenty-four-hour glucose absorption was measured in 50 CAPD patients and 17 APD patients. Absorption was calculated from the glucose remaining in the 24-hour spent dialysate. Wilcoxon sign rank statistical analysis showed the D/D0 formula results to be closer to actual glucose absorbed (CAPD: p = 0.0153; APD: p = 0.0001). The D/D0 formula is individualized for patients' modality and membrane characteristics and easy to calculate from readily available information.

Absorption↗
PubMed1993

The 24-hour D/P ratio is a convenient screen for identifying altered peritoneal transport rates.

Peritoneal transport characteristics (PTC) may change without peritonitis, surgery, or other insults. Identifying patients with these changes is essential in adjusting the dialysis prescription to achieve optimal peritoneal dialysis on a long-term basis. Frequent standard peritoneal equilibration tests (PETs) become impractical as the population in individual programs expands. The time demands are burdensome to the nursing staff as well as to the patient. The accuracy of fast PETs is dependent upon the patient's exact adherence to the protocol steps. Utilizing the 24-hour D/P as a marker for altered PTCs has improved the efficiency of our approach to repeating standard PETs and ensuring dialysis adequacy. For adequacy studies, pooled 24-hour dialysate is routinely collected in our unit. The 24-hour D/P ratio correlates well with extrapolations from original PET data and the patient's current dwell times. Discrepancies noted between the patient's actual D/P ratio and the patient's expected D/P ratio alert the clinician to possible PTC changes.

Biological Transport↗
PubMed1993

[Methodologic comparison of the analysis of urinary calculi. Roentgen diffractometry, polarization microscopy and microscopic-microchemical component analysis].

Not only instrumental, apparative or operative stone extraction is necessary for patients with urolithiasis (particularly those with recurrent urolithiasis); preventive treatment is also called for, and for this exact analysis of the composition of the stones is essential. The procedures currently accepted as standard for stone analysis are: X-ray diffraction, infrared spectroscopy, polarisation microscopy and the complicated chemico-quantitative analyses performed in some institutes. Recently a new, so-called microscopic-microchemical, analysis of stone components has been presented (the Harzalith). To test the value of this procedure as compared to e.g. X-ray diffraction or polarization microscopy, a comparative study was carried out in our department. Thirty different urolith compositions (calculi with one and with more components) were analysed qualitatively and quantitatively by three methods. No qualitative difference was found between X-ray diffraction and polarization microscopy; however, there was a difference from the Harzalith method, and with increasing number of components there was hardly any correspondence with the other methods. Only 10% of the calculi with three or four components could be analysed correctly. Often, too many components were determined by the new method. The test material was analysed by three laboratory assistants working independently of each other.

Cholelithiasis↗
PubMed1992

Localisation of hypoxanthine phosphoribosyl transferase in the malaria parasite Plasmodium falciparum.

The enzyme hypoxanthine phosphoribosyl transferase of the human malaria parasite Plasmodium falciparum has been located in parasites and parasite-infected erythrocytes by antibody probing. The probe was a polyclonal rabbit antiserum made against the parasite enzyme made in Escherichia coli. The enzyme is associated with membrane-bound compartments in merozoites and asexual blood parasites. In particular, indirect immunofluorescence studies reveal the enzyme localized in vesicle-like structures within the cytoplasm of the infected erythrocyte. This is the first time a P. falciparum protein of defined metabolic function has been tracked to a site outside the parasite cytosol. Studies on the targeting of the enzyme using a cell-free system suggests that the protein reaches its destination via a route different from the normal secretory pathway.

Amino Acid Sequence↗
PubMed1992

Sensitive and specific serodiagnosis of invasive amebiasis by using a recombinant surface protein of pathogenic Entamoeba histolytica.

A recombinantly expressed protein, recEh-P1, representing part of an immunodominant surface antigen of pathogenic Entamoeba histolytica, was used for serodiagnosis of invasive amebiasis. Expression was performed under the control of a T7-RNA promoter by using a modified procaryotic expression vector, designated pHisT7. This vector allowed high-yield expression of recEh-P1 fused to a stretch of sequence containing eight histidine residues, which facilitated purification by metal chelate affinity chromatography on Ni2+ columns under highly denatured conditions. Purified recEh-P1 was found to be water soluble after prolonged dialysis and was used as the antigen for the detection of antiamebic serum antibodies by immunoblotting and enzyme-linked immunosorbent assay. In both tests all sera of patients with invasive amebiasis reacted to recEh-P1 whereas none of those collected from healthy controls, including individuals with noninvasive amebiasis, or from patients suffering from bacterial or protozoan infections unrelated to E. histolytica did so.

Amino Acid Sequence↗
PubMed1992

Intermolecular cleavage of hepatitis A virus (HAV) precursor protein P1-P2 by recombinant HAV proteinase 3C.

Active proteinase 3C of hepatitis A virus (HAV) was expressed in bacteria either as a mature enzyme or as a protein fused to the entire polymerase 3D or to a part of it, and their identities were shown by immunoblot analysis. Intermolecular cleavage activity was demonstrated by incubating in vitro-translated and radiolabeled HAV precursor protein P1-P2 with extracts of bacteria transformed with plasmids containing recombinant HAV 3C. Identification of cleavage products P1, VP1, and VPO-VP3 by immunoprecipitation clearly demonstrates that HAV 3C can cleave between P1 and P2 as well as within P1 and thus shows an activity profile similar to that of cardiovirus 3C.

Capsid↗