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Biomedical subjects

C Mulder

Publications and source records attributed to C Mulder.

At least 55 records · Page 3Linked to original sources

A rapid and sensitive immunosorbent assay for urinary albumin.

We describe a fast, simple and sensitive microtiter scale competitive ELISA for the determination of urinary albumin. All reagents are commercially available. In the standard procedure, a minimum concentration of 0.8 mg albumin/L can be measured, although, applying another dilution, 0.04 mg/L can be detected. Within-batch coefficient of variation was 6.9% and 5.6% (at 1:20 and 1:50 dilution, respectively); between-batch variation was 8.6% and 5.6% respectively. The influence of urine pH and other urine components is minimised in the assay diluting with a casein-containing buffer.

Albuminuria↗

Epstein-Barr virus-positive and -negative B-cell lines can be infected with human immunodeficiency virus types 1 and 2.

Human immunodeficiency virus type 1 (HIV-1) can infect CD4+ lymphocytes, monocytes-macrophages, and various other cell lines, including B-cell lines. To study the parameters of B-cell infections, we examined the susceptibility of 24 B-lymphoid cell lines to both HIV-1 and HIV-2 infections. These cell lines included a series of Epstein-Barr virus (EBV) genome-negative Burkitt's lymphoma cell lines and their EBV-converted counterparts. To infect these cells we used two HIV-1 isolates and one HIV-2 isolate. Infections were monitored with a cytoplasmic RNA dot-blot and a syncytium assay. HIV infection was also studied by a novel method based on electrophoresis of DNA liberated from cells that were lysed in situ in the well of an agarose gel. All human B-cell lines could be infected with HIV-1, regardless of the presence of EBV genomes; thus, EBV infection had no major effect on HIV susceptibility of B-cell lines. Integrated proviral HIV genomes could be detected by Southern blot analysis of DNA extracted from long-term, non-HIV-producing B-cell lines. This study suggests that B-lymphoid cells may serve as reservoirs for latent or persistent HIV infections in vivo, even in the absence of EBV infection.

B-Lymphocytes↗

Effects of protein intake variation and omega-3 polyunsaturated fatty acids on renal function in chronic renal disease.

Fifteen patients with chronic renal disease of various origin were investigated after 4 weeks protein restriction, after 4 weeks high protein intake and finally, after 8 weeks dietary supplementation with omega-3 polyunsaturated fatty acids (PUFA's), while adhering to a high protein intake. The highest values for effective renal plasma flow and glomerular filtration rate were observed after 8 weeks dietary supplementation with omega-3 PUFA's without a relationship with baseline values. Calculated renal resistance fell after omega-3 PUFA supplementation. Whether long term dietary supplementation with omega-3 PUFA's will influence the progression of chronic renal insufficiency in man needs further study.

Adult↗

Virus-associated hemophagocytic syndrome: identification of an immunoproliferative precursor lesion.

Virus-associated hemophagocytic syndrome (VAHS) is a nonneoplastic, generalized histiocytic proliferation with marked hemophagocytosis associated with a systemic viral infection. Histologic studies of lymph nodes usually show lymphoid depletion and histiocytic proliferation. In this report we describe the case of a patient with Epstein-Barr virus-associated VAHS in which initial lymph node biopsy samples showed an immunoproliferative lesion that preceded the usual generalized histiocytic proliferation. This finding suggests that some cases of VAHS may have an immunoproliferative precursor lesion.

Adult↗

In vitro immortalization of marmoset cells with three subgroups of herpesvirus saimiri.

Sequences within the rightmost 7 kilobases of the unique L DNA of herpesvirus saimiri are required for oncogenicity of the virus. The same DNA region has been found to be highly variable among different strains of herpesvirus saimiri. On the basis of this variability, herpesvirus saimiri strains were classified into groups A, B, and non-A, non-B. Herpesvirus saimiri strains representing the three groups were used successfully for in vitro immortalization of phytohemagglutinin-activated, interleukin 2 (IL-2)-expanded peripheral blood lymphocytes of common marmosets (Callithrix jacchus). Peripheral blood leukocytes could be immortalized from only a subset of common marmosets (5 of 13). All of the immortalized cell lines contained covalently closed circular viral DNA molecules and initially showed a low level of virus production. Cells immortalized by group A and group non-A, non-B strains did not require IL-2 in the medium. However, the only group B immortalized cell line, 473-SMHI, did not grow well in the absence of IL-2. The different characteristics of cell lines immortalized by herpesvirus saimiri strains belonging to different groups may help to elucidate some functions coded by the highly variable DNA region which is involved in the oncogenic process.

Animals↗

The composition of plasma lipoproteins and erythrocyte membranes in cholesterol-fed pigs with partial ileal bypass.

The composition of plasma lipoproteins and erythrocyte membranes was studied in cholesterol-fed pigs with a partial ileal bypass. Cholesterol feeding caused marked increases in the plasma concentrations of cholesterol and phospholipids. In spite of continuation of cholesterol feeding, PIB reduced plasma concentrations of cholesterol and phospholipids towards basal values. PIB completely counteracted the dietary cholesterol induced alterations in the lipid composition of the apoprotein B containing plasma lipoproteins, but not in the HDL2 fraction. It is suggested that PIB specifically influences the metabolism of the atherogenic, apoprotein B containing lipoproteins. Dietary cholesterol caused significant increases in the ratios of cholesterol:phospholipids and phosphatidylcholine: sphingomyelin in erythrocytes. The high-cholesterol diet also increased the content of linoleic acid in erythrocyte phosphatidylcholine. PIB completely nullified the cholesterol-induced increase in the cholesterol:phospholipid ratio, but not the increase in the phosphatidylcholine:sphingomyelin ratio. The percentage of linoleic acid in erythrocyte phosphatidylcholine was unaffected by PIB. Neither cholesterol feeding nor PIB had an effect on the lipid fluidity of erythrocyte membranes, as measured by fluorescence polarization, using the probe diphenylhexatriene. Possible compensatory mechanisms operating to control homeostasis of lipid fluidity of erythrocyte membranes are discussed.

Animals↗

Pathogenesis of B cell lymphoma in a patient with AIDS.

Lymphoma occurs at increased frequency in patients with the acquired immunodeficiency syndrome (AIDS). We studied, using serologic and molecular techniques, one such lymphoma for (a) evidence of infection with human T lymphotropic virus, type III (HTLV-III), and Epstein-Barr virus (EBV), (b) monoclonal rearrangement of immunoglobulin and T cell receptor genes, and (c) rearrangement of the c-myc oncogene. Immunoglobulin and T cell receptor gene studies demonstrated that the tumor was of monoclonal B cell origin. Similar to cases of Burkitt's lymphoma unrelated to AIDS, there were DNA sequences in the lymphoma that hybridized to EBV-specific probes and demonstrated evidence of c-myc rearrangement. HTLV-III sequences were not detected in the malignant B cells. The pathogenesis of some B cell neoplasms in patients with the syndrome may involve transformation by EBV and deregulation of oncogene expression without direct infection of the malignant B cells by HTLV-III.

Acquired Immunodeficiency Syndrome↗

[Corneal opacity].

A case with bilateral corneal opacification in the form of a half-ring is described. Routine laboratory tests revealed no abnormalities, and serum lipoprotein composition was normal. The authors suspect that this was a case of primary lipoidal keratopathy.

Adult↗

Herpesvirus sylvilagus infects both B and T lymphocytes in vivo.

Herpesvirus sylvilagus infection of cottontail rabbits (Sylvilagus floridanus) was studied as a model of herpesvirus-induced lymphoproliferative disorders. Leukocytosis, splenomegaly, proliferation of T cells and virus production by lymphocytes characterized this infectious mononucleosis-like disease. Approximately two copies of circular herpesvirus sylvilagus genomes per cell were detected in spleen cells at 2 weeks postinfection, and circular genomes could still be observed after 4 months. Circular viral genomes were found in both B and T lymphocytes. Small amounts of linear viral DNA (0.1 to 0.3 copies per cell) were also detected in both B and T cells. These results indicated that the virus did not replicate in the majority of lymphocytes in vivo. Herpesvirus sylvilagus infection in cottontail rabbits could be useful as a model for studying the complex virus-host relationships of lymphotropic herpesviruses and perhaps as an animal model for Epstein-Barr virus infection in humans.

Animals↗

Serum lipoproteins in cholesterol-fed pigs after partial ileal bypass.

Partial ileal bypass (PIB) surgery was performed in hypercholesterolaemic mini-pigs and Yorkshire pigs fed a semipurified diet containing 1% (W/W) of cholesterol. PIB drastically reduced serum total cholesterol and phospholipid concentrations and the cholesterol: phospholipid ratio in spite of continuation of cholesterol feeding. The relative distribution of cholesterol between serum lipoproteins was affected by PIB; the surgical treatment caused an increase in the ratio of high-density lipoprotein (HDL) to low-density lipoprotein (LDL) cholesterol. Serum apo B and apo A levels were rapidly decreased by PIB. The operation induced a decrease in the cholesterol: apo B and cholesterol: apo A ratios. It is suggested that the pig is a suitable animal model to study PIB-induced changes in lipoprotein metabolism.

Animals↗

Epstein-Barr virus-associated hemophagocytic syndrome: virological and immunopathological studies.

The virus-associated hemophagocytic syndrome (VAHS) is a disorder characterized by a benign, generalized histiocytic proliferation, with marked hemophagocytosis associated with systemic viral infections. We have studied the virological and immunopathological events occurring in two children experiencing Epstein-Barr VAHS. Neither of the patients had an underlying immunodeficiency and both recovered from their disease and are completely well one year after follow-up. In each patient, evidence for primary Epstein-Barr virus (EBV) infection was documented with a typical humoral immune response, including IgM antibody directed against virus capsid antigen. EBV was demonstrated in lymphoreticular tissues by electron microscopy and molecular hybridization studies. Permissive EBV infection was suggested by the finding of mature virus particles and linear viral DNA in lymphoreticular tissues. Immunopathological studies demonstrated complete effacement of lymph node architecture by a marked proliferation of immunoblasts in patient 1 and infiltration and effacement of the lymph node architecture with benign-appearing histiocytes in patient 2. Atypical lymphocytes characteristic of acute EBV infection were notably absent in the peripheral blood of both patients and cytotoxic T cells, which normally lyse EBV-infected B cells, were also absent from the peripheral circulation. Our observations suggest that EBV-induced VAHS may be the result of an increased virus burden in the face of immunoregulatory cell imbalances.

Bone Marrow Examination↗