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Biomedical subjects

S L Yang

Publications and source records attributed to S L Yang.

At least 181 records · Page 10Linked to original sources
PubMed1980

Interstitial twin pregnancy.

A rare case of interstitial twin pregnancy is presented. The attendant difficulties of ultrasonography and the important role of laparoscopy in the diagnosis and management of this unusual condition are discussed.

Adult↗
PubMed1979

Nucleophile in the active site of Escherichia coli galactose-1-phosphate uridylyltransferase: degradation of the uridylyl-enzyme intermediate to N3-phosphohistidine.

The [32P]uridylyl-enzyme intermediate form of Escherichia coli galactose-1-P uridylyltransferase can be converted to a [32P]phosphoryl-enzyme by first cleaving the ribosyl ring with NaIO4 and then heating at pH 10.5 and 50 degrees C for 1 h. After alkaline hydrolysis of the [32P]phosphoryl-enzyme the major radioactive product is N3-[32P]phosphohistidine. A lesser amount of 32Pi is also produced as a side product of the hydrolysis of N3-[32P]phosphohistidine. No N1-phosphohistidine, N-phospholysine, or phosphoarginine can be detected in these hydrolysates. It is concluded that the nucleophile in galactose-1-P uridylyltransferase to which the uridylyl group is bonded in the uridylyl-enzyme intermediate is imidazole N3 of a histidine residue. This degradation procedure should have general applicability in the degradation and characterization of nucleotidyl-proteins.

Chemical Phenomena↗
PubMed1979

Immune response after vaginal application of antigens in the rhesus monkey.

The immune response after vaginal application of antigens was investigated in six sexually mature female rhesus monkeys. Two model antigens, i.e., lipopolysaccharide (LPS) OF Salmonella typhosa and abortive type T-4 coliphages were applied with or without adjuvant. A plastic sponge used as the antigen carrier was introduced into the upper vagina and placed against the ectocervix. For primary immunization, each monkey received 18 vaginal antigen applications and 10 applications for each booster course. For comparison, three other female rhesus monkeys were immunized systemically. Alum or LPS was used as adjuvant. Blood was obtained two times and cervical mucus three times weekly from each monkey. Antibodies were only barely detectable in cervical mucus after the primary vaginal immunization. However, booster treatments resulted in definite antibody responses. Specific antibodies were also detected in the circulating blood after vaginal booster immunization. The antibody level in cervical secretion in three of four cases was higher than that in circulatin blood. Systemic immunization resulted in high levels of circulating antibodies, but less than 10% appeared in cervical secretions. A characteristic decrease in antibody levels in cervical mucus was usually observed at midcycle after local immunization as well as after systemic immunization. More than 90% of T-4 coliphages applied vaginally were absorbed within 48 hours. Although alum appeared to retard the absorption of antigens, it seemed to enhance the local response. More than 90% of the antibodies to the T-4 coliphages could be removed from the serum and cervial mucus by treatment with anti-immunoglobuin G antiserum. The lymphocyte response to antigens was studied by measuring the 3H-thymidine uptake by peripheral blood lymphocytes in culture. A positive response was observed in three of three systemically immunized and in only two of six locally immunized aminals. In general, the immune response was significantly weaker after local vaginal immunization than after systemic immunization.

Animals↗
PubMed1979

Ectopic pregnancy. An eight-year review.

Ruptured ectopic pregnancy constitutes a major gynecologic emergency that may result in death. From January 1968 through December 1975, 313 patients with ectopic pregnancy were treated at Chicago Lying-In Hospital. The historical and physical findings, diagnostic procedures, causative factors and patient management are reviewed and discussed. The most common symptoms were abdominal pain and amenorrhea. More than half the patients were misdiagnosed prior to admission. Only 30% had distinct adnexal masses. The treatment of choice was salpingectomy unless the opposite tube was absent or damaged. Three deaths occurred in this series. Only 31% of the patients gave histopathologic evidence of pelvic inflammatory disease.

Abortion, Spontaneous↗
PubMed1977

Transport of [14C]Gly-Pro in a proline peptidase mutant of Salmonella typhimurium.

The transport of [14C]Gly-Pro was examined using a mutant of Salmonella typhimurium (strain TN87) deficient in an X-Pro dipeptidase and an X-Pro-Y iminopeptidase. The dipeptide was taken up by one saturable transport system having a Km of 5.3-10(-7)M and a V of 1.4 nmol/mg dry wt cell per min. The uptake of Gly-Pro was not inhibited by amino acids or tripeptides and the transport system exhibited a rather broad side chain specificity for dipeptides. Dipeptides containing hydrophobic residues were the most potent inhibitors of this dipeptide transport system exhibiting Ki values between 10(-8) and 10(-7) M. In contrast, dipeptides containing glycine residues were particularly weak inhibitors. Finally, Gly-Pro was found to be in the intact form inside the cell and was concentrated more than 1000-fold.

Amino Acids↗
PubMed1976

Effect of serum proteinase inhibitors on the fertilizing capacity of rabbit spermatozoa.

The in vivo effect of purified human alpha1-antitrypsin and inter-alpha-trypsin inhibitor on the fertilizing ability of capacitated rabbit spermatozoa was investigated and compared with that of the trypsin-kallikrein inhibitor from bovine organs (Trasylol). Only 250 mug of alpha1-antitrypsin/5 X 10(4) sperm in 0.05 ml inhibited fertilization by more than 50%. Lower concentrations of alpha1-antitrypsin (50 mug/5 X 10(4) sperm in 0.05 mo) and inter-alpha-trypsin inhibitor in amounts of 250 mug/5 X 10(4) sperm and less had no significant effect on the fertilization rate. Comparative experiments with Trasylol in conentrations of 50 mug/5 X 10(4) sperm resulted in more than 50% fertilization inhibition, whereas 100 mug/5 X 10(4) sperm decreased the fertilization rate by approximately 90%. The differences in the antifertility effect of these acrosin inhibitors toward capacitated spermatozoa may be due to differences in molecular weight. The effective concentrations required for fertilization inhibition appear to be relatively high under the experimental conditions used.

Alpha-Globulins↗
PubMed1975

Immunologic aspects of term pregnancy toxemia. A study of immunoglobins and complement.

IgA, IgG, and IgM were measured by the single radial immunodiffusion method in umbilical cord and maternal sera in toxemia patients and in normal term pregnant cases. Complement (C' 3) levels were determined only in maternal sera. Quantitation of IgA, IgG, and IgM was performed in concentrated serial urine samples from three eclamptic and three normal control patients. Results show that there are lower IgG and IgM levels in the sera of mothers with toxemia of pregnancy; however, paradoxically higher IgM levels were detected in cord sera from their newborn infants without evidence of placental leakage or increased neonatal infection. The finding of the low IgG and IgM levels appears to be due in part to immunoglobin loss into the urine. The unchanged complement levels in toxemia, in this study, are not suggestive of an active immunologic process, but the high IgM in the newborn infants of toxemic mothers is unexplained and may represent active immunologic disease. Clearly, investigations of tissue binding and the formation of immunoglobin complexes should be carried out to better explain these abnormal findings.

Blood Protein Electrophoresis↗
PubMed1975

Preparation of 14C-labeled sterigmatocystin in liquid media.

14C-labeled sterigmatocystin was prepared from surface cultures of Aspergillus versicolor A-18074 maintained in liquid media by multiple additions of (1-14C)acetate to the cultures. The highest yield of 7.75 mg/10 ml was found with a sucrose-asparagine-ammonium medium in which more than 3% of the radioactivity of the added (1-14C)acetate was recovered ithe purified (ring-14C) sterigmatocystin. The method offers an easy way to prepare 14C-labeled sterigmatocystin for studies of this mycotoxin.

Acetates↗
PubMed1973

Male specific antigen: homology in mice and rats.

Male lymphoid cells from some strains of rats can sensitize C57BL/6 female mice against C57BL/6 male skin grafts; this indicates that the male specific antigen of these two species is homologous.

Animals↗