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Biomedical subjects

W M Huang

Publications and source records attributed to W M Huang.

At least 73 records · Page 4Linked to original sources
PubMed1983

Improved section adhesion for immunocytochemistry using high molecular weight polymers of L-lysine as a slide coating.

Poly-L-lysine (PPL) has been used to coat glass slides in the preparation of tissue sections for immunocytochemical staining. The adhesive properties of different molecular weight (m.w.) polymers of L-lysine have been tested on pre-fixed cryostat sections which were subjected to a 3 day washing treatment. It has been found that the higher the molecular weight of the polymer, the greater the adhesive force it provides. PLL (m.w. 350,000) at concentrations in the range of 0.05-0.1% was found to be the most effective polymer.

Adhesiveness↗
PubMed1983

Vasoactive intestinal polypeptide in the normal and unstable bladder.

The possible involvement in idiopathic detrusor instability of a newly discovered type of autonomic nerve containing vasoactive intestinal polypeptide (VIP) has been studied. Immunocytochemistry and radioimmunoassay, using specific antibodies against VIP, were carried out on 20 biopsy specimens from the bladders of patients with detrusor instability and 20 specimens from control patients. The concentration of VIP in the unstable bladders was found to be markedly reduced from 36.52 +/- 4.8 pmol/g (mean +/- SEM) to 7.62 +/- 1.84 pmol/g (P less than 0.01). The number of VIP immunoreactive nerves was greatly decreased in all of the layers but particularly in the muscle layer of the unstable bladder in comparison with the controls. These findings may provide important information about the mechanism of this disorder.

Adult↗
PubMed1982

Identification of the origins of T4 DNA replication.

Two physical origins of T4 DNA replication were determined by hybridization of viral DNA prepared 2.5 min after infection to a display of total T4 DNA. This is the earliest time after T4 infection of Escherichia coli at 37 degrees C that labeled and hybridizable DNA can be detected. The two origins, separated by about 25 kilobases, were identified and localized in the early region of the T4 map. One of them is located in a 5.6-kilobase EcoRI fragment containing genes 62-46. The other is located between genes rI and e in a 1.9-kilobase EcoRI fragment. Both of these T4 fragments have been cloned and their interactions with the host cell are discussed.

Base Sequence↗
PubMed1980

An unusual electrocardiographic pattern of left ventricular endocardial pacing.

Pacemaker stimulation of the left ventricle is expected to yield a pattern of complete right bundle branch block, however, unusual patterns have been reported. The present report is a case of an unusual electrocardiographic pattern from left ventricular endocardial pacing in a patient with an atrial septal defect and acute myocarditis complicated by complete degree atrioventricular block.

Adult↗
PubMed1979

Abnormalities of neurotransmitter enzymes in Huntington's chorea.

The activities of L-glutamate decarboxylase (GAD), GABA-transaminase (GABA-T), choline acetyltransferase (CAT), and cysteic and cysteinesulfinic acids decarboxylase (CAD/CSAD) in putamen and frontal cortex in both Huntington's chorea and normal tissues were measured. The greatest difference between Huntington's and normal tissues occurred in putamen, in which the apparent CSAD activity was reduced by 85%, while no difference was observed in frontal cortex. GAD, CAD, and CAT activities were also reduced in putamen by 65%, 63%, and 42%, respectively (P less than 0.05). Slight reduction in the enzyme activities was also observed in frontal cortex. However, these reductions appeared to be statistically insignificant (P greater than 0.05 in all cases). GABA-T showed little difference in both putamen and frontal cortex in Huntington's chorea and normal tissues. GAD and GABA-T from Huntington's tissues were indistinguishable from those obtained from normal tissues by double diffusion test and by microcomplement fixation test, which is capable of distinguishing proteins with a single amino acid substitution. Furthermore, the similarity of the complement fixation curves for GAD from Huntington's and normal tissues suggests that the decrease in GAD activity is probably due to the reduction in the number of GAD molecules, presumably through the loss of neurons, and not due to the inhibition or inactivation of GAD activity by toxic substances which might be present in Huntington's chorea.

4-Aminobutyrate Transaminase↗
PubMed1979

T4 DNA-delay proteins, required for specific DNA replication, form a complex that has ATP-dependent DNA topoisomerase activity.

Under some conditions, T4 DNA replication requires the products of the DNA-delay genes, genes 39, 52, 58, and 60. By using an in vitro complementation assay that stimulates DNA replication in T4 39(-)-infected cell extracts, T4 gene 39 protein has been purified. The purified fraction also contains complementing activities for T4 genes 52 and 60. On sodium dodecyl sulfate/polyacrylamide gel analysis the purified preparation exhibits three protein components: a 51,000-dalton protein corresponding to the product of gene 52, a 64,000-dalton protein corresponding to the product of gene 39, and a 110,000-dalton protein. This purified fraction shows a DNA topoisomerase activity that untwists superhelical DNA in an ATP- and Mg2+-dependent reaction. The analogs adenylyl imidodiphosphate and adenyl [beta, gamma-methylene]diphosphonate cannot be used to replace ATP. The topoisomerase activity is not sensitive to the antibiotics oxolinic acid and novobiocin, known antagonists of Escherichia coli DNA gyrase. The possible relationship among the three polypeptides and their biological activities is discussed.

Adenosine Triphosphate↗
PubMed1979

Inhibition of initiation of bacteriophage T4 DNA replication by perturbation of Escherichia coli host membrane composition.

3-Decynoyl-N-acetylcysteamine (3-decynoyl-NAC) is an analog which specifically causes the immediate cessation of the biosynthesis of unsaturated fatty acids in Escherichia coli, whereas the synthesis of saturated fatty acids is actually stimulated. As a result, the cell membrane accumulates saturated fatty acids in its phospholipid. Addition of the inhibitor at the time of infection of E. coli by T4 phage had no effect on normal phage replication and development, implying that the synthesis of unsaturated fatty acids per se has little effect on T4 DNA replication. However, if the integrity and composition of the bacterial membrane was grossly perturbed by first treating the cells with the inhibitor for 60 min before infection, the proper initiation and the attainment of a rapid rate of T4 DNA synthesis were not observed. Under these conditions, a full complement of T4 early proteins was synthesized. The membrane associability of the known DNA delay proteins induced by wild-type T4 phage in the treated cells resembled that expected of a culture of untreated cells infected with a DNA delay mutant. When any one of three DNA delay mutants was used to infect 3-decynoyl-NAC-treated cells, T4 DNA replication was aborted. These findings suggest that some kind of specific interactions among the initiation proteins defined by the DNA delay mutants and the bacterial membrane may be necessary to facilitate the normal initiation and rapid rate of T4 DNA replication. A model for the involvement of the three different initiation proteins and the subsequent attainment of rapid DNA synthesis is discussed.

Cell Membrane↗
PubMed1978

Tissue alkaline phosphatase activity in selected freshwater teleosts.

1. Kinetic studies of tissue alkaline phosphatase activity were carried out on eight species of teleost fishes taken from the Mississippi River. 2. Liver alkaline phosphatase activity expressed in mumoles of p-nitrophenol released per minute per gram of protein were as follows: Micropterus salmoides, 20.31; Stizostedion vitreum, 19.22; Pomoxis nigromaculatus, 18.76; Lepisosteus platostomus, 16.26; Esox lucius, 16.14; Hiodon tergisus, 13.83; Ictalurus punctatus, 10.87; Aplodinotus grunniens, 7.94. 3. Specific activity of the kidney alkaline phosphatase was about ten times the level of liver alkaline phosphatase for the species examined.

Alkaline Phosphatase↗
PubMed1974

Synergistic interactions of T4 early proteins concerned with their binding to DNA.

Under appropriate conditions, 19 distinct early proteins produced by bacteriophage T4 bind DNA with various affinities. They include products of genes that have been implicated in T4 DNA metabolism, such as DNA negative, DNA arrest, and DNA delay genes, and others whose roles have not yet been defined. The identifiable DNA-binding proteins are the products of genes 43, rIIA, 46, 30, 39, 52, betagt, 32, and internal protein III. In some cases, protein-protein interactions are involved in the formation of the DNA-protein complexes.

Centrifugation, Density Gradient↗