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Biomedical subjects

H S Ko

Publications and source records attributed to H S Ko.

32 records · Page 2Linked to original sources
PubMed1984

Dissociation of stimulatory capacity in mixed lymphocyte reaction and proliferative responses to pokeweed mitogen among peripheral blood non-T cells.

The stimulatory capacity in mixed lymphocyte reaction (MLR) and responsiveness to pokeweed mitogen (PWM) by peripheral blood non-T cells were studied. E rosette- and adherent cell-depleted lymphocytes were divided into low, medium and high density populations using discontinuous Percoll gradient. Low density non-T cells were potent stimulators in both autologous and allogeneic MLR despite low proliferative response to PWM. In contrast, those with medium density showed weaker stimulation in autologous though not in allogeneic reactions and underwent strong blastogenesis in PWM cultures. Non-T cells with high density had low MLR-stimulatory capacity and yet manifested the highest stimulation indices on PWM stimulation. These findings suggest that functional characteristics of non-T cells may be separable on the basis of cell density.

Antigens, Surface↗
PubMed1980

Peripheral blood Ia-positive T cells. Increases in certain diseases and after immunization.

The Ia antigens, usually expressed primarily on B lymphocytes, are found on a small percentage of normal peripheral blood T cells (average 2.6% by fluorescence and 10.8% by rosette assay). Elevated levels up to 40% by both assays were observed in a high proportion of patients with rheumatoid arthritis. Increases also were found in patients with systemic lupus erythematosus and various types of infections. The increases were evident with a specific heteroantiserum, a hybridoma reagent, and DR specific alloantisera. Normal levels were present in multiple sclerosis and an assortment of metabolic and other disorders. A rise in similarly positive T cells occurred in normal individuals after immunization with tetanus toxoid or PPD. The cells primarily involved in all of these instances were small lymphocytes, which stained relatively weakly with the fluorescent reagents and were readily distinguishable from T-cell blasts. They were found to be enriched in isolated T gamma fractions but were also found in other T cells. The accumulated evidence indicated that these cells represent an expansion of one or more subsets of T cells found in normal individuals, and that their level in the peripheral blood may serve as an index of immunological stimulation.

Arthritis, Rheumatoid↗
PubMed1979

Ia determinants on stimulated human T lymphocytes. Occurrence on mitogen- and antigen-activated T cells.

Human T-cell blasts were generated by stimulation with mitogens and antigens. A proportion of these blasts expressed Ia antigens detectable by immunofluorescence with both allo- and hetero-antiserums. The maximal expression of Ia antigens was delayed and usually occurred after the peak of blastogenesis. Among the three mitogens used, pokeweed mitogen (PWM) was most effective in giving a high percentage and intense Ia staining of T-cell blasts. Phytohemagglutinin and concanavalin A blasts gave weaker and lower percentages of Ia staining. Activation by alloantigens and soluble antigens such as tetanus toxoid and purified protein derivative resulted in Ia expression on T cells comparable to PWM stimulation. Depletion of Ia+ cells from freshly isolated T cells with anti-Ia and complement decreased subsequent Ia expression, suggesting that a proportion of Ia+ blasts were derived from Ia-bearing peripheral blood T cells. When the specificities of the Ia antigens on T-cell blasts were examined with alloantiserums, it was evident that the T blasts expressed similar HLA-DR determinants to those on B cells from the same donor; occasional minor differences between stimulated T cells and autologous B-cell lines or fresh B cells were encountered.

Cells, Cultured↗
PubMed1978

Ia-bearing T lymphocytes in man. Their identification and role in the generation of allogeneic helper activity.

The presence of Ia-like antigens was demonstrated on a small population (2-6%) of highly purified human circulating T lymphocytes by immunofluorescence with a rabbit anti-Ia serum raised against the isolated bimolecular Ia structure. The Ia+ T lymphocytes have no surface or intracellular immunoglobulins. The expansion of this Ia+ T-cell population was encountered in certain patients. Ia antigens were also found on T blasts grown in long-term cultures with conditioned medium generated by phytohemagglutinin-stimulated lymphocytes. In addition, leukemia blasts which stained for Ia antigens and formed E rosettes were identified in the peripheral blood of two leukemic patients. This evidence further supports the existence of Ia-bearing T cells in man. The Ia+ T-lymphocyte population was shown to contain cells responsible for the generation of allogeneic helper activity. Elimination of Ia+ lymphocytes from a purified T-cell population by the anti-Ia antiserum and complement abolished its ability to help an allogeneic B-cell preparation to generate plaque-forming cells against sheep erythrocytes in vitro in the presence of the antigen.

Antigens, Surface↗
PubMed1976

M components-a review of 1242 cases.

Among 1242 patients referred for immunologic investigation 1255 M components were detected in the serum. Of these patients 50.9% had multiple myeloma, 18.1% had nonmyelomatous malignant diseases such as macroglobulinemia, lymphoma, leukemia or cancer, 4.3% had connective tissue diseases, 2.5% had primary generalized amyloidosis (PGA) and the rest had various "benign" conditions. Whereas IgG was the commonest M component in multiple myeloma, connective tissue diseases and the other benign conditions, IgM was the commonest M component in lymphoma and leukemia; Bence Jones proteinemia was most frequently observed in PGA. The ratio of kappa to lambda light chains varied from 1.7:1 in IgG myeloma to 1:9 in IgD myeloma, and was 1:2.1 in PGA. Bence Jones protein was detected in 422 (66%) of 640 urine samples tested, the prevalence ranging from more than 70% in multiple myeloma and PGA to as low as 36% in various benign conditions. It is evident that the class and type of M components and the presence of Bence Jones proteinuria have no definite significance with regard to the diagnosis. Therefore, thorough investigation and follow-up at regular intervals are required when M components are detected.

Adult↗
PubMed1976

Immunologic abnormalities in a patient with multiple neoplasms.

Pernicious anemia, antithyroid antibodies, IgG(K) M component, depressed production of other immunoglobulins and impaired function of peripheral blood lymphocytes developed in a patient with adenocarcinoma of the colon, transitional-cell carcinoma of the tongue and clear-cell parathyroid adenoma. This case demonstrates that immunologic abnormalities and multiple malignant neoplasms may coexist in one patient. It lends support to the hypothesis that neoplastic processes and autoimmunity may both be related to impaired immune surveillance.

Adenocarcinoma↗
PubMed1976

Polymyositis in a patient with multiple neoplasms.

A 64 year old woman with a past history of panhysterectomy and oophorectomy for carcinoma of the body of the uterus (1950) and partial colectomy for carcinoma of the colon (1971), presented in 1972 with severe weakness of the proximal girdle muscles and histological evidence of polymyositis. A detailed search disclosed no tumor and she was treated with prednisone. Two years later, investigations for iron deficiency anemia revealed two polyps in the colon. Pathological examination of the resected colon disclosed two separate foci of adenocarcinoma and a number of adenomatous polyps. Three months later, further investigations for melena led to the discovery of a gastric carcinoma. Due to the extent of the tumor, she was subjected to gastrectomy. splenectomy, and excision of the tail of the pancreas, but died of postoperative complications. At autopsy, no residual cancer was detected, but a meningioma was found. The association of polymyositis with malignant tumors has been recognized for a long time, but only two previously reported patients have had more than one cancer. Although a causal relationship is difficult to establish, continued vigilance for neoplasms is advocated during the follow-up period.

Colonic Neoplasms↗
PubMedDate not supplied

Portal vein erosion and acute abdominal hemorrhage as a complication of acute pancreatitis.

The case of a 35-year-old male with portal vein erosion and acute life-threatening abdominal hemorrhage as a complication of acute pancreatitis is reported. Erosion of arterial walls is the most common complication of pancreatitis and pancreatic pseudocysts, and erosion of the portal vein leading to a fistula between the pancreas and the portal vein is very rare. Diagnosis was made by multislice spiral computed tomography, and nonsurgical treatment was elected, leading to complete recoverage.

Acute Disease↗
PubMedDate not supplied

M components associated with lymphoma: a review of 62 cases.

Sixty-two of 1242 patients with M components were found to have lymphoma. There were 33 patients with immunoglobulin M(IgM), 20 WITH IgG, 5 with IgA, and one patient with Bence Jones protein M components. Three patients had biclonal gammopathy. The types of lymphoma were: lymphocytic, 31; histiocytic, 12; mixed cell, 4; stem cell, 2; Burkitt's, 1; Hodgkin's disease, 9; and unclassified, 3. All patients were in stages III or IV of lymphoma, and the average duration of disease was 29.3 months when M components were detected. Anemia, abnormal peripheral blood lymphocytes, and lymphomatous involvement of the bone marrow were especially common among patients with IgM M components. Osteolytic lesions were found in 12 patients and osteosclerotic lesions in one. A second malignancy occurred in eight patients. The level of M component was below 1.0 gm/dl in 55 per cent of patients. Significant suppression of normal immunoglobulin levels in the serum was noted in 4 and 16 patients with IgG and IgM components, respectively. Bence Jones proteinuria was found in 19 per cent, cryoglobulinemia in 11 per cent, and cold agglutinins, all of anti-i specificity, in 10 per cent of the patients. Most of the M components decreased during therapy. Only two M components gradually increased. The mean survival of 39 patients who died was 10.4 months. The living patients have been followed for a mean period of 21.2 months. The presence of M components in lymphoma may suggest B cell origin of the tumor but the coexistence of plasma cell dyscrasia cannot be ruled out.

Adult↗
PubMedDate not supplied

A rapid and sensitive cellular enzyme-linked immunoabsorbent assay (CELISA) for the detection and quantitation of antibodies against cell surface determinants. II. Optimal reagent concentrations and predictive analysis.

A cellular enzyme-linked immunosorbent assay (CELISA) was developed for the detection and quantification of antibodies elicited against allogeneic cell surface determinants. The technique uses a solid-phase cell matrix created by fixing cells with a mild formalin solution onto the bottom of a 96-well microtiter plate. A primary layer of alloantisera is first reacted against rat target cells. The secondary antibody, peroxidase conjugated antirat IgG, is then added to each well and serves as the second sandwich layer. Optimal reagent concentrations were determined by serial dilution analysis of various cell concentrations and secondary antibody dilutions. It was found that 200,000 cells per well was the optimal target cell concentration. However, 100,000 cells per well was also sufficient to run the assay with acceptable performance characteristics. Even lower cell concentrations of 10,000 and 20,000 cells/well, although not optimal, also produced acceptable results. Secondary antibody concentration with respect to the optimal cell concentration was determined to be 1:500. At 200,000 cells per well and a 1:500 secondary antibody dilution, the assay presented excellent coefficients of determination and high positive to negative ratios. The reaction was found to be very sensitive in yielding high antibody titers with low background levels and could be defined mathematically as a linear-log function. Titers of multiple unknown alloantibody samples were easily and accurately predicted in an automated manner by regression analysis form known standards. This immunoassay will be useful in studies of cell surface determinant expression and quantitation of antibodies reactive to such markers.

Animals↗
PubMedDate not supplied

Fluoride levels in whole saliva of preschool children after brushing with 0.25 g (pea-sized) as compared to 1.0 g (full-brush) of a fluoride dentifrice.

Concerns regarding an increased risk of dental fluorosis related to ingesting fluoride-containing toothpastes by preschool children have led to recommendations to reduce the amount of toothpaste used for young children to a pea-sized amount. The purpose of this study was to determine the effect on salivary fluoride levels of reducing the amount of toothpaste used in a preschool-age (4-5 years) population. Salivary fluoride concentrations were determined for 10 children whose teeth were brushed with both 0.25 g and 1.0 g of a fluoridated toothpaste on two separate days. Initial salivary fluoride levels following the use of 0.25 g of toothpaste were less than half of the salivary fluoride concentrations when 1.0 g of toothpaste was used, and levels returned to baseline more rapidly. The reduced salivary fluoride levels when less toothpaste is used may result in a reduced efficacy for caries prevention. However, any potential reduction in caries prevention may still be outweighed by the risk of increased fluoride ingestion with larger amounts of toothpaste in preschool children. The results of this study suggest that a reduction in the amount of a fluoridated toothpaste to a pea-sized amount be limited only to young children who are at risk of ingesting toothpaste.

Cariostatic Agents↗