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Biomedical subjects

S Jothy

Publications and source records attributed to S Jothy.

At least 91 records · Page 5Linked to original sources
PubMed1983

Murine alveolar hydatidosis: a potential experimental model for the study of AA-amyloidosis.

Histochemical and immunohistologic evidence has been presented to characterize the AA-type of amyloidosis in C57BL/6J (H-2b) mice infected i.p. with 50 cysts of Echinococcus multilocularis. Congo red-stained sections of kidneys and spleens from 4 weeks postinfected (p.i.) hydatid-mice were negative for the amyloid deposits. Heavy amyloid deposits, which in ultrathin sections of kidneys measured 8-12 nm in thickness, obliterated the perifollicular sinuses in spleens and glomerular capillaries in kidneys at 16 weeks p.i. Amyloid deposits were resistant to potassium permanganate treatment. They bind strongly to rabbit anti-mouse AA serum (RAA) as demonstrated by using peroxidase-anti-peroxidase technique. Preabsorption of RAA with azo-casein induced amyloid abolished completely the binding of RAA to mouse AA and hydatid-mouse deposits. Rabbit monospecific mouse antisera to heavy and light chains of Igs did not bind to amyloid deposits in hydatid-mice kidneys. Enumeration of spleen cells from the 16 weeks p.i. amyloidotic spleens showed a significant reduction in the total lymphocytes and T-cells. Overt accumulation of amyloid deposits in the spleen was associated with its disorganization, a significant reduction in T-cells and the depressed response of spleen cells to ConA and LPS mitogens. The relationship between proliferating alveolar hydatid cyst, intense inflammatory response, depressed cell mediated immunity and AA-type of amyloidosis is discussed in murine hydatidosis.

Amyloidosis↗
PubMed1982

Intravascular malignant histiocytosis mimicking central nervous system vasculitis: an immunopathological diagnostic approach.

A 53-year-old man presented with a lumbosacral polyradiculoneuropathy and developed fluctuating encephalopathy suggestive of multifocal small vessel disease. Postmortem examination demonstrated multifocal vascular occlusion by undifferentiated cells confined to the intravascular space. Extravascular spread was found only in spleen and liver. The presence of lysozyme and absence of factor VIII in the cytoplasm of the malignant cells confirmed their histiocytic nature. This patient had an unusual intravascular form of malignant histiocytosis that must be included in the differential diagnosis of multifocal vascular disease.

Arteries↗
PubMed1982

Amyloidosis in experimental murine alveolar hydatidosis.

Male mice (eight to ten weeks old, C57BL/6J, H-2b strain) were inoculated intraperitoneally with 50 Echinococcus multilocularis cysts each and killed 12 and 17 weeks later. The alveolar cyst masses were weighed and the spleens and kidneys fixed for light and electron microscopy of sections. Amorphous eosinophilic deposits in both were extensive and there were apple-green birefringent deposits visible under polarized light in all the glomeruli. The presence of amyloid was confirmed by electron microscopy.

Amyloid↗
PubMed1982

Monoclonal antibodies to human lung tumor antigens demonstrated by immunofluorescence and immunoprecipitation.

Various studies have demonstrated the usefulness of monoclonal antibodies in recognizing discrete tumor antigenic determinants. The present study describes the tissue reactivity of monoclonal antibodies prepared against a squamous cell carcinoma of the lung. Antigens were purified from the tumor extract by anti-beta 2 microglobulin affinity chromatography. These beta 2-associated antigens demonstrated tumor specificity by the leukocyte adherence inhibition assay. Antibody-secreting hybridomas were generated by fusion of mouse myeloma cells with mouse spleen cells immunized with purified tumor antigens. Hybridomas were selected by a solid-phase tumor membrane-binding immunoassay. The target specificity of the secreted monoclonal antibodies was ascertained by radioimmunoprecipitation analysis and indirect immunofluorescence on various human tumor and normal tissue sections. Monoclonal antibody-secreting hybridomas 48.4.8 and 48.4.2 secreted immunoglobulin that selectively immunoprecipitated polypeptide fragments from human lung tumor membrane antigens. Hybridoma 9.2.2 secreted antibody that was strongly positive by indirect immunofluorescence on all tested lung squamous cell carcinomas. Adjacent or intervening normal lung tissue did not display significant immunofluorescence. Adenocarcinomas of the lung were negative or focally positive when focal squamous cell differentiation was present. Oat cell carcinomas were negative. The secreted antibody did not significantly stain three extrapulmonary tumors or a variety of normal tissues.

Animals↗
PubMed1981

Renal involvement in malignant histiocytosis. An immunoperoxidase marker study.

In two patients who had malignant histiocytosis, renal involvement was present at an early stage of their diseases and consisted clinically of proteinuria and renal failure. The associated renal lesion was characterized by a diffuse and global endocapillary hypercellularity of the glomeruli imputable to atypical cells occluding the capillary loops. Immunoglobulins were absent from this lesion. The atypical cells were positively identified by lysozyme immunoperoxidase study as malignant histiocytes. It is suggested that renal biopsy complemented by marker study could play a role in the diagnosis of malignant histiocytosis.

Aged↗
PubMed1981

Presence of monocytes in systemic lupus erythematosus-associated glomerulonephritis: marker study and significance.

The presence and significance of monocytes in the glomerular lesions of 13 renal specimens obtained from ten patients with systemic lupus erythematosus-associated nephritis were studied. The monocytes were identified by the presence of intracytoplasmic lysozyme, as demonstrated by immunoperoxidase staining on paraffin-embedded tissue. Eight specimens obtained from six patients displayed monocytes. These were found most often associated with mesangial hypercellularity, and their appearance fluctuated with it. There was a positive correlation between the number of lysozyme-positive cells and the amount of proteinuria. We conclude that monocytes contribute to the endocapillary hypercellularity and affect protein filtration in lupus nephritis.

Antibodies, Antinuclear↗
PubMed1975

The role of membrane proteins and phospholipids in the interaction of ribosomes with endoplasmic reticulum membranes.

Hydrolysis of the membrane proteins and phospholipid headgroups of rat liver rough endoplasmic reticulum membranes showed that the ribosomal binding sites involve membrane proteins susceptible to low concentrations of trypsin, chymotrypsin, and papain. Three membrane proteins having molecular weights of 120 000, 93 000 and 36 000 are found to be altered by trypsin and chymotrypsin treatment. Also the polar headgroup of phosphatidylinositol appears to play a role in the binding process.

Binding Sites↗
PubMedDate not supplied

The levels and biologic action of the human neutrophil granule peptide HP-1 in lung tumors.

HP-1 is the most abundant human representative of a recently discovered class of neutrophil cystine- and arginine-rich peptides. These peptides have many potentially regulatory activities expressed at nanomolar concentrations. To establish the levels of HP-1 that can accumulate in human lung tumors and nondiseased lung fragments, tissues were extracted for their peptide content. The extracts were purified on reverse phase HPLC, and HP-1 and related peptides were identified by sequence analysis and their concentrations in the tissue quantitated by amino acid analysis. Immunohistochemistry was performed and strongly suggests that HP-1 is confined to granulocytes under most circumstances, and indicates that the levels of HP-1 measured in the tumors reflect the levels obtained when solid tissue is infiltrated by neutrophils. The maximum observed levels were 26 nanomoles per gram wet weight of tissue. Attempts were then made to correlate this level to the cytotoxic potential of HP-1 by performing in vitro cytotoxicity dose-response curves on several cell lines. Most cells were killed at between 1 and 8 microM, and the response depended on the growth conditions of the cells. The levels of HP-1 that accumulate in tumors can exceed the in vitro cytolytic concentrations. The levels are also considerably in excess of those required to exert in vitro regulatory actions.

Amino Acid Sequence↗
PubMedDate not supplied

Nuclear location of the p55 subunit of the IL-2 receptor following activation of the HT-2 T helper cell line.

After mitogenic or antigenic stimulation, T cells express interleukin-2 receptors (IL-2R). The mechanism and control of signal transduction following binding of IL-2 to IL-2R are poorly understood. Using two rat monoclonal antibodies (5A2 and 7D4) specific for two distinct epitopes of the p55 subunit of mouse IL-2R, we have studied the cellular localization of this molecule by immunocytochemistry during the IL-2-mediated activation of mouse T helper cell clone HT-2. During the activation cycle, nuclear staining for the p55 subunit of the IL-2 receptor was transiently observed. It is suggested that the transient nuclear location of the IL-2R may play a critical role in the control of T-cell activation, proliferation and/or differentiation.

Animals↗
PubMedDate not supplied

Loss of heterozygosity of methylenetetrahydrofolate reductase in colon carcinomas.

Folate derivatives are essential for DNA synthesis and methylation. A large proportion of the Caucasian population is heterozygous for a common substitution, 677C-->T (alanine-->valine), in methylenetetrahydrofolate reductase (MTHFR), an enzyme of folate interconversion. Homozygous mutant individuals, approximately 10-15% of North Americans, have been reported to have a reduced risk of colorectal cancer. We examined lymphocyte and tumor tissue DNA from colorectal carcinoma patients from two different populations to assess loss of heterozygosity (LOH) of MTHFR. We observed LOH in approximately 16% of colorectal tumors; in 8 of the 11 tumors with LOH, the mutant valine allele was lost. Additional studies are required to determine if preferential loss of the mutant allele is a common finding that could contribute to colorectal tumorigenesis.

Alleles↗
PubMedDate not supplied

CD44s expression mitigates the phenotype of human colorectal cancer hepatic metastases.

Alterations in expression of the CD44 adhesion protein have been implicated in colorectal tumourigenesis. Overexpression of variant high molecular weight isoforms (especially CD44v6), as well as down-regulation of standard CD44 (CD44s), are postulated to result in increased tumourigenicity. We studied the metastatic phenotype produced by the expression of CD44s by stable transfection into a human colorectal carcinoma cell line, SW620, that shows absence of any CD44 expression. Splenic injection of 2 x 10(6) SW620 colon cancer cells into SCID mice was used to produce hepatic metastases. The animals were sacrificed at 6 weeks after injection and morphological end-points relating to macrometastases and micrometastases were studied CD44s expression was associated with decreased development of macroscopic tumours (0.9 vs 3.0 tumours/ mouse liver, p = 0.004), less extensive tumour replacement of the liver (2.6% vs 12.8%, p = 0. 04) and decreased numbers of micrometastases (3.8 x 10(-8) vs 7.9 x 10(-8) micrometastases/ microm2, p = 0.2). This study is the first to demonstrate the mitigating effect of CD44s expression on the hepatic metastatic phenotype in a colorectal carcinoma cell line that does not ordinarily express CD44.

Animals↗