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Biomedical subjects

H Huang

Publications and source records attributed to H Huang.

At least 595 records · Page 33Linked to original sources
PubMed1987

Development of articulation before delayed hard-palate closure in children with cleft palate: a cross-sectional study.

The development of articulation before surgical closure of the hard palate was compared in 75 preschool children with cleft lip and palate and 40 preschool children born without clefts. The children were aged 2 years to 5 years 11 months. The patients had significantly poorer articulation skills than the controls at each age level. Substitutions were the most frequent error, and they did not decrease with age in the patients. Fistula size and a history of speech therapy were significant factors in the articulation error scores only in 5-year-olds. No advantage in articulation proficiency was found for those who had worn a prosthesis to occlude the hard-palate defect.

Articulation Disorders↗
PubMed1987

Identification and isolation of mycoplasmas by immunobinding.

This laboratory has developed an immunobinding assay (IBA) to identify and detect mycoplasmas in a variety of specimens. The specimen is inoculated in volumes of 10 microliters onto nitrocellulose (NC) paper, which is then blocked, fixed, and incubated at room temperature. Specific antimycoplasma polyclonal or monoclonal antibody is first added, followed by peroxidase-labeled antibody directed toward the first immunoglobulin. Alternately, antimycoplasma IgG can be purified and conjugated to horseradish peroxidase for use in a direct assay. Addition of a developing solution results in the formation of purple color when mycoplasmas are present. Titers of rabbit antimycoplasma antisera range from 1:1,000 to 1:30,000. This assay can detect approximately 1 x 10(4) colony-forming units (CFU). This IBA has been used routinely to identify mycoplasmal isolates from 132 infected cell cultures. In addition, the procedure successfully detected Mycoplasma pneumoniae in throat swabs from patients with respiratory illness within 2 h. Perfect correlation was obtained with the IBA and microbiological culture of throat swabs for M. orale, M. salivarium and M. pneumoniae. The procedure was successfully used for other Mollicutes. It detected ureaplasmas in urogenital swabs and corn stunt spiroplasmas in infected corn plants and leafhoppers. A modification of the technique has been developed that identifies mycoplasma colonies on agar. It has also been used to assay for antimycoplasma antibodies in serum.

Animals↗
PubMed1987

[In vitro studies of the cell cycle of mouse myelomonocytic leukemia using a fluorescence activated cell sorter and autoradiography].

Cell cycle and various phase time of mouse myelomonocytic leukemia cells were studied in vitro with Fluorescence Activated Cell Sorter (FACS 420, Becton-Dikinson FACS Systems, Sunnyvale, CA, USA) in testing cellular DNA content and with autoradiography. At the same time, doubling time was calculated by counting the number of cells cultured in vitro within 6 days following implantation. According to the cellular DNA content, the proportions of various cell phases in the whole cell population were as follows: G1, S and G2 plus M phases take up 30.5%, 47.9% and 21.6%. Basing on autoradiography and direct counting, the cell number, the cell cycle, duration of various cell phases and doubling time were as follows: LI = 98.0%, MI = 1.7 +/- 0.9%, TG1 = 4.9 hrs, TS = 8.0 hrs, TG2 = 2.8 hrs, Tm = 0.3 hr, TC = 16.0 hrs, TD = 17.0 hrs. FACS assay showed that the duration of various cell phases are quite similar to that calculated by autoradiography. Therefore a simple and rapid FACS method may be widely used in the studies of cell cycle instead of autoradiography if estimating computer program is available.

Animals↗
PubMed1986

Deletion mapping of Sindbis virus DI RNAs derived from cDNAs defines the sequences essential for replication and packaging.

Defective-interfering (DI) genomes of a virus contain sequence information essential for their replication and packaging. They need not contain any coding information and therefore are a valuable tool for identifying cis-acting, regulatory sequences in a viral genome. To identify these sequences in a DI genome of Sindbis virus, we cloned a cDNA copy of a complete DI genome directly downstream of the promoter for the SP6 bacteriophage DNA dependent RNA polymerase. The cDNA was transcribed into RNA, which was transfected into chicken embryo fibroblasts in the presence of helper Sindbis virus. After one to two passages the DI RNA became the major viral RNA species in infected cells. Data from a series of deletions covering the entire DI genome show that only sequences in the 162 nucleotide region at the 5' terminus and in the 19 nucleotide region at the 3' terminus are specifically required for replication and packaging of these genomes.

Base Sequence↗
PubMed1985

Upper- vs lower-limb systolic blood pressure in full-term normal newborns.

The difference between upper- vs lower-limb systolic blood pressure (BP) was investigated in 100 normal full-term newborns younger than 24 hours of age by the oscillometric method. The mean systolic BP of both upper limbs was 72.3 +/- 7.6 mm Hg (mean +/- SD). The mean +/- SD systolic BP of both lower limbs was 71.3 +/- 8.2 mm Hg. Systolic BP in the upper limb was greater than that in the lower limb in 66% of newborns by as much as 20 mm Hg (mean +/- SD, 3.5 +/- 3.1). Systolic upper-limb BP was lower than systolic lower-limb BP in 28% of newborns by as much as 21 mm Hg (mean +/- SD, 5.1 +/- 5.1). Systolic BP did not correlate with birth weight. Follow-up evaluation of BP in 25 of the infants up to 3 years of age revealed higher systolic BP in the lower extremities in 24 of the 25 infants. We conclude that (1) it is normal to have a higher systolic BP in either the upper limb or the lower limb in newborns younger than 24 hours of age, and (2) there is no correlation of systolic BP with birth weight in full-term normal neonates younger than 24 hours of age.

Arm↗
PubMed1984

Studies on alternaria allergens. IV. Comparative biochemical and immunological studies of commercial Alternaria tenuis Batches.

The biochemical and immunological characteristics of a series of commercial samples of Alternaria tenuis were examined, including samples from two different companies. There was a considerable variation in the biochemical parameters such as the gel filtration profile on Sephadex G-100, isoelectric focussing pattern and immunodiffusion precipitin band pattern. The content and proportion of two high molecular weight polysaccharides, one a galactomannan and the other a glucan, also varied greatly. In contrast, the allergenic properties of the samples were more consistent. In rat IgE passive cutaneous anaphylaxis tests, extensive cross-reactivity was observed among batches from the same company, but this cross-reactivity was weaker when batches from the two companies were compared. In direct radioallergosorbent tests (RAST) the samples showed similar reactivities, but RAST inhibition tests showed a 40-fold range in activity between samples from one company and 55-fold between batches from the two sources. It was found that the proportions of the major A. tenuis allergen and a related hypoallergenic antigen in the samples were relatively constant, hence RAST inhibition can be used as a measure of allergenic potency despite the presence of this cross-reacting antigen. The lack of correlation between allergenic and biochemical properties of the various samples suggest that a simple biochemical test is unlikely to be a satisfactory replacement for the RAST inhibition assay in standardizing A. tenuis extracts.

Allergens↗
PubMed1983

Management of the antenatal preterm fetal lung in the prevention of respiratory distress syndrome in lambs.

We have explored change in pulmonary compliance before, and after, repeated deep insufflation of the lungs to a pressure of 35 cm H2O, in 130-days gestation fetal lambs delivered by cesarean section, and while still connected to the intact umbilical cord and the ewe. As a group, all 15 out of 28 fetal lambs that had a rise in total compliance to above 0.2 ml (cm H2O)-1 kg-1 after the first inflation, tolerated 24 h of mechanical ventilation with excellent health and good lung function; only 3 animals out of 13 that showed no similar initial rise in compliance after the first inflation, ultimately survived. We believe the first deep insufflation is an important therapeutic intervention and a useful index to rapidly assess chance of survival in a high-risk fetal lamb population.

Animals↗
PubMed1982

Prevention of hyaline membrane disease in premature lambs by apneic oxygenation and extracorporeal carbon dioxide removal.

Hyaline membrane disease is found only in lungs where pulmonary ventilation has been established, i.e. after birth. We delivered eleven fetal lambs of a gestational age of 128-130 days but instead kept their lungs in total apnea and inflated to constant pressure, while removing all metabolically produced carbon dioxide with an extracorporeal membrane lung. Oxygen was provided by the membrane lung, and by apneic oxygenation through the natural lungs. Hence, arterial blood gases remained always normal, without any pulmonary ventilation. After 6-66 h the lungs had sufficiently cleared to allow normal mechanical pulmonary ventilation in 10 our of 11 lambs so treated. In a control group treated with mechanical ventilation alone, five of seven lambs died within the first 24 h of severe hyaline membrane disease.

Animals↗
PubMed1982

Antibody and MHC genes.

The striking homology relationships, both in sequence and in general organizational features, among the genes encoding antibodies, transplantation antigens and beta 2-microglobulin suggest that these genes are members of a supergene family. It will be interesting to determine whether any of the regulatory strategies displayed by the antibody gene families will also be employed by the MHC gene families. Indeed, the recombinant DNA approach has given us profound insights into the organization and expression of antibody genes. These same techniques are now beginning to unravel the mysteries of the MHC complex. It is clear that the future will require a much closer collaboration between molecular biologists, cellular immunologists, and immunogeneticists to obtain the appropriate reagents and cell lines necessary to expand our understanding of the molecular biology and enzymology of gene expression in these fascinating systems.

Animals↗
PubMed1982

Studies on Alternaria allergens. III. Effect of Alternaria tenuis on the humoral response to three T cell-dependent antigens in rats.

The effects of an extract of the saprophytic mold, Alternaria tenuis (AT-CE) on the humoral response to a ragweed allergen extract (DWSR), ovalbumin and sheep red blood cells (SRBC) was investigated in female Wistar rats. Animals pretreated with 100 micrograms or 2 mg AT-CE showed enhancement (p less than 0.05) in the reaginic response (IgE antibody) to DWSR at 25 and 18 days postimmunization. On the other hand, animals posttreated with AT-CE showed substantial reduction in anti-DWSR IgE antibody response. Contrasting results were obtained when ovalbumin was used as an immunizing antigen. There was a remarkable enhancement in the reaginic response to ovalbumin in rats pre- or posttreated with 10 micrograms of AT-CE. Pretreatment with AT-CE did not affect the hemagglutination titers to ovalbumin, while posttreatment with 100 micrograms or 1 mg AT-CE increased the hemagglutination titers of IgM antibody. There was a significant reduction in hemagglutinin, and hemolysin titers to SRBC in animals pretreated with all concentrations of AT-CE; at day 21, suppression was noted in animals pre- or posttreated with all concentrations of AT-CE. On the other hand, greatly increased hemagglutination titers were found in animals posttreated with 100 micrograms or 1 mg AT-CE. Hence, enhancement and suppression can both occur depending on the dose and time of administration of AT-CE together with the nature of the immunizing antigen.

Alternaria↗