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Biomedical subjects

Y J Choi

Publications and source records attributed to Y J Choi.

At least 127 records · Page 7Linked to original sources
PubMed1988

Effects of compensatory growth on milk protein gene expression and mammary differentiation.

This experiment was conducted to develop an understanding of mechanisms responsible for effects of a compensatory (stair-step) growth pattern on the expression of milk protein genes and mammary differentiation. One hundred thirty weanling female rats were randomly assigned to either a control or a test group (compensatory growth). Early lactating mammary tissues from the compensatory growth group showed an increase in the RNA:DNA ratio, protein:DNA ratio, DNA, RNA, and protein while exhibiting a decrease in the lipid content as compared with those of the control group (2.2, 1.6, 1.7, 3.8, 2.8, and 0.5 times, respectively). Mammary tissues from the compensatory growth group contained about 1.1- to 1.4-fold more total cytoplasmic mRNA for caseins and whey acidic protein than those of the control group. The compensatory growth pattern increased beta-casein mRNA accumulation, milk protein secretion, and amino acid uptake in mammary acinar culture (1.3, 1.3, and 1.1 times, respectively) compared with those of the control group. These results indicate that the compensatory growth pattern increases milk protein mRNA transcripts and may contribute to an increase in the functional activity of the mammary gland.

Adrenal Cortex Hormones↗
PubMed1988

Casein gene expression in bovine mammary gland.

The objectives were to examine the rate of synthesis of casein mRNA transcripts in bovine mammary tissue at different hormonal states and to study the effects of hormonal stimuli (insulin, hydrocortisone, and prolactin) on the accumulation of casein mRNA and on the rate of protein secretion by epithelial cells from bovine mammary tissues. Total cytoplasmic RNA was extracted from mammary tissues of cows obtained by biopsy (8 mo pregnant) and upon slaughter (lactating). The relative specific activities of cytoplasmic mRNA for alpha s1-, alpha s2-, beta-, and kappa-casein were about 3.2, 4.6, 3.3, and 4.5-fold higher in tissues of lactating cows than in those of 8 mo pregnant cows. Mammary alveolar epithelial cells retained hormone-inducible milk protein gene expression for total milk protein gene expression for total milk protein secretion and for alpha s1- and beta-casein messages. Prolactin, even in the absence of insulin and hydrocortisone, induced significant amounts of milk protein mRNA. Hydrocortisone in the presence of prolactin amplified the lactogenic effects on mammary epithelium. Maximal induction of beta-casein mRNA and protein secretion occurred when all three hormones were present.

Animals↗
PubMed1987

Effect of compensatory growth on regulation of growth and lactation: response of dairy heifers to a stair-step growth pattern.

The primary objective of this study was to improve the productive efficiency of growth via optimal use of both high fiber-low quality and high energy-high protein feeds in diets for growing dairy cattle. Twenty Holstein heifers were randomly assigned to either a control or treatment group. The control diet met the National Research Council (NRC) requirement for .45 kg/d gain, with heifers calving at 24 to 26 mo of age. The test groups were fed according to a 5-2-5-2 mo schedule in which the nutrient density was alternately 15% below or 40% above the NRC requirement. Results showed that the heifers on the test dietary regimen (compensatory growth) gained more and consumed less, resulting in significantly improved efficiency of growth (body gain/dry matter intake X 100), energy (body gain X 1,000/metabolizable energy (ME) intake) and protein utilization (body gain/protein intake X 100) in comparison to control animals (13.0 vs 7.3%; 57.9 vs 32.6 g/Mcal ME; 96.5 vs 54.2%, respectively). Marked changes in average concentration of urea-N, glucose, triglycerides, cholesterol and lecithin cholesterol acyltransferase activity in blood were seen for test heifers during the stair-step growth phase (i.e., alternating maintenance and compensatory). Evidence from this experiment suggests that the phased growth (stair-step) system offers a simple, practical and cost-effective method for raising dairy heifers.

Animal Feed↗
PubMed1983

Hepatitis B virus: a possible cause of serositis in hemodialysis patients.

An epidemiologic survey in a maintenance hemodialysis population of 300 patients was undertaken to relate the appearance of acute serositis (pericarditis, pleuritis or ascites) to HBsAg antigenemia. A significant number of incidents of serositis occurred in patients acutely or chronically infected with hepatitis B surface antigen (HBsAg) suggesting an etiologic role for the virus in the serositis of uremia. In 2 patients with both end-stage renal disease and chronic HBsAg antigenemia, immunofluorescent studies of serosal tissues showed fluorescent clusters interpreted to be HBs antigen-antibody complexes. It is concluded that an immunologic response to viremia may be one of the causes of serositis in uremia.

Adult↗
PubMed1982

Responses of chronic lymphocytic leukemic lymphocytes to increasing concentrations of phytohemagglutinin during short-term culture.

Lymphocytes obtained from CLL patients containing high and low peripheral lymphocyte cell counts were cultured in the absence and presence of increasing concentrations of phytohemagglutinin for periods of up to 2 h. Lymphocytes from patients with low cell counts (less than 50,000/mm3) were stimulated to incorporate 3H-uridine during the 1st h of culture by concentrations of PHA ranging from 1 to 32 microgram/ml. Under identical conditions, lymphocytes from patients with high cell count (greater than 50,000/mm3) were barely affected. During the 2nd h of culture the above concentrations stimulated to a lesser degree the former group of lymphocytes, whereas it inhibited incorporation by the latter group. The results obtained suggest a qualitative difference in the response of CLL lymphocytes to PHA in accordance with the progression of the disease.

Cells, Cultured↗
PubMed1981

Ultrastructural "fingerprint" in cryoprecipitate and glomerular deposits: a case report of systemic lupus erythematosus.

A 20 year old woman had lupus nephritis and cryoglobulinemia. The cryoglobulins isolated from the serum and a renal biopsy specimen were studied by means of immunofluorescence, immunochemistry, and electron microscopy. Ultrastructural "fingerprint" structures were observed both in the cryoprecipitate and in the glomerular deposits, as were IgG, IgM, and IgA. These observations furnish morphologic evidence for the glomerular deposition of cryoglobulins in lupus nephritis.

Adult↗
PubMed1981

The effect of steroids on the synthesis of RNA by isolated T and B lymphocytes of normal donors and patients with chronic lymphocytic leukemia.

T- and B-lymphocyte populations were isolated from peripheral blood of 11 patients who had chronic lymphocytic leukemia (CLL) and four normal healthy donors. The isolated T and B cells were cultured in the absence and presence of cortisol, dexamethasone, beta-estradiol, testosterone, and progesterone, and the effects of these steroids on the synthesis of RNA was investigated. T and B cells of the CLL group were significantly more inhibited in the synthesis of RNA than the respective cells of the normal control group. The individual responses of T and B cells to each of the steroids differed in both the CLL and control groups, as well as between the respective subpopulations of each of the groups. Analysis of th LDH isoenzyme patterns of T and B cells of each group suggested major differences in the distribution of their LDH isoenzymes.

Aged↗
PubMed1980

Immunofluorescence of renal lesions in paraffin-embedded and fresh-frozen sections.

Immunofluorescent findings in formalin-fixed and paraffin-embedded sections of kidneys involved by various nephropathies compared favorably with those in fresh-frozen sections. In some cases, the findings in paraffin-embedded sections were complementary. Immunoreactivity with complement could not be demonstrated.

Complement System Proteins↗
PubMed1979

Immunological observations following vasectomy.

Lymphocytotoxic antibodies (LCA) against panels of normal lymphocytes and leukemic B-cells were demonstrated in vasectomized men. Since vasectomy is known to induce antibody formation to spermatozoa, the demonstration of these lymphocytotoxic antibodies may be related to antigenic constituents of spermatozoa such as HLA or B-cell alloantigens. Long term follow-up is needed to clarify the clinical significance of these antibodies.

Antibodies↗
PubMed1979

Immunoblastic sarcoma following Waldenström's macroglobulinemia.

Immunoblastic sarcoma has been observed in association with, or subsequent to, chronic immune stimulation, connective tissue disorders, and immunoblastic lymphadenopathy. A case of Waldenström's macroglobulinemia progressinng after a few years into immunoblastic sarcoma is reported. Splenectomy led to disappearance of hemolytic anemia and of pulmonary infiltrates, as well as to marked reduction of macroglobulins. Although immunoblastic sarcoma usually terminates fatally within two or three months, complete remission was induced by combination chemotherapy. It is speculated that Waldenström's macroglobulinemia, immunoblastic lymphadenopathy, and immunoblastic sarcoma are related disorders reflecting a clonal nature of immunoblastic lymphoma cells and the plasmacytic cells.

Adult↗
PubMedDate not supplied

Metanephric adenoma of the kidney: case report.

Metanephric adenoma is an extremely rare, epithelial, renal tumor with characteristic histology. This tumor is invariably benign. We report a case of metanephric adenoma diagnosed by ultrasound-guided needle biopsy.

Adenoma↗