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Biomedical subjects

A C Wong

Publications and source records attributed to A C Wong.

16 recordsLinked to original sources
PubMed1990

Biosynthetic human growth hormone in the treatment of growth hormone deficiency.

A total of 309 previously untreated children with growth hormone deficiency (GHD) (219 boys, 90 girls; mean age 8.4 +/- 3.9 years, range 1.5-19 years) were treated for up to 3 years in an ongoing trial designed to examine the long-term efficacy and safety of biosynthetic somatropin (rhGH). The children were treated with rhGH, 0.06 mg/kg (0.16 IU/kg) three times weekly. In the prepubertal children, the mean height velocity increased during the first year from 3.8 +/- 1.8 cm/year to 8.9 +/- 2.2 cm/year (n = 188). During the second and third years, their height velocities were 7.1 +/- 1.1 (n = 147) and 6.3 +/- 1.2 cm/year (n = 64), respectively. The height velocity SDS increased from -2.5 +/- 1.9 before treatment to 3.1 +/- 2.6 during the first year of treatment in the prepubertal children. The mean pretreatment height velocity in those with idiopathic GHD (3.8 +/- 1.6 cm/year) did not differ from that in children with organic GHD (3.8 +/- 2.3 cm/year). In addition, the height velocities during the first year of therapy did not differ significantly with respect to the aetiology of GHD. For the children who entered puberty during the study, the mean height velocity increased from 3.0 +/- 1.7 cm/year before treatment to 8.4 +/- 2.3 cm/year during the first year of rhGH therapy. In the first year, the height velocity of children with a bone age of less than 5 years (9.4 +/- 2.3 cm/year) was significantly greater than that in children with a bone age of 5-10 years (8.4 +/- 1.8 cm/year) or greater than 10 years (7.8 +/- 2.2 cm/year: p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Effect of environmental conditions on production of toxic shock syndrome toxin 1 by Staphylococcus aureus.

The kinetics of toxic shock syndrome toxin 1 (TSST-1) production by Staphylococcus aureus was studied in a fermentor in which aeration rate, atmospheric composition, pH, and temperature were controlled. The toxin was synthesized at a maximal rate during the exponential phase. High bacterial populations were not necessarily accompanied by high TSST-1 yields. Aerobiosis increased TSST-1 production, but excessive aeration had an adverse effect. Addition of CO2 enhanced TSST-1 yield by increasing toxin production rate and efficiency. Cultures with no pH control made more TSST-1 than those maintained at pH 5.5 to 7.5. Maximum TSST-1 yields were obtained when cultures were supplied with air (20 cm3/min) and CO2 (5 cm3/min) via a sintered glass sparger.

Bacterial Toxins↗
PubMed1989

Investigation by improved syringe method of effect of tampons on production in vitro of toxic shock syndrome toxin 1 by Staphylococcus aureus.

Twenty-seven types of commercial tampons from five manufacturers were tested in a sealed-syringe method to determine their effect on the growth of Staphylococcus aureus and the production of toxic shock syndrome toxin 1. In this improvement of the syringe method, the available air is limited to that which is contained within the sealed syringe containing the tampon. The culture medium was buffered, and blood and CO2 were included in the incubation to better simulate the vaginal environment during menstruation. Variables of tampon weight, composition, air volume, and absorbency were examined for their effect on the production of toxic shock syndrome toxin 1. Generally, with the exception of brand E, toxin production in the presence of tampons was equal to or lower than that in a sealed control syringe containing air but no tampon.

Analysis of Variance↗
PubMed1988

Restriction fragment length polymorphism in the interzeta hypervariable region for prenatal diagnosis of non-deletion alpha thalassemia.

A Bam HI restriction fragment length polymorphism in the interzeta hypervariable region (IZ HVR) of the zeta-alpha gene cluster was used for the prenatal diagnosis of a pregnancy at risk for Hb H hydrops fetalis. The parents had zeta-alpha thalassemia 1 and non-deletion alpha thalassemia, respectively, and a previous hydrops was missed using the conventional method of gene detection. In this prenatal diagnosis, linkage to IZ HVR was used to exclude non-deletion alpha thalassemia, and the numbers of zeta and alpha genes in the fetus were quantitated to predict the exact genotype. Confirmation was made by analysis of cord blood at delivery.

Amniocentesis↗
PubMed1988

Restriction fragment length polymorphisms associated with factor VIII:C gene in Chinese.

Twenty-six unrelated hemophilia A and 70 unrelated normal chromosomes in 184 subjects were studied to determine the frequencies of intragenic and intergenic restriction fragment length polymorphisms associated with the factor VIII:C gene. The incidences for positive BclI and BglI polymorphic sites in the Chinese were 82% and 100%, respectively. Both were higher than in other ethnic groups, while the incidence for XbaI polymorphism was 57%, which is similar to that reported in Caucasians. Using the St14.1 probe, two polymorphic TaqI allelic systems in the DXS52 region were detectable, with heterozygous rates of 0.712 (for system I, alleles 1 to 8) and 0.495 (for system II, alpha and beta alleles), respectively. Thus, using a combination of four polymorphisms, it would be possible to offer carrier detection or prenatal diagnosis in 96% of Chinese females at risk.

China↗
PubMed1988

A simple method for the treatment of the inverted nipple.

We introduce a simple method for correcting the inverted nipple in which there is preservation of the lactiferous duct, less surgical invasion, and negligible scar formation. Our method consists of two parts: releasing fibrous tissue around the lactiferous ducts, and keeping the nipple in the everted position with a bolster suture and milk suction pump.

Adolescent↗
PubMed1987

Primary culture of squamous head and neck cancer with and without 3T3 fibroblasts and effect of clinical tumor characteristics on growth in vitro.

Twenty-one tumors from patients with squamous cell carcinoma of the head and neck (SCC H/N) were cultured with and without 3T3 fibroblasts in order to determine whether, on the basis of improved tissue culture medium, 3T3 cells could be deleted without altering growth and cloning efficiency. Thirty-five additional primary SCC H/N specimens, cultured in the presence of 3T3 fibroblasts, were studied to assess the effect of tumor differentiation, site of primary tumor, and site of specimen procurement on growth. The authors conclude that 3T3 cells remain essential for optimal growth and cloning efficiency. Also, 3T3 cells improved the number of successful cultures by 33% to 100% depending on the plating density, and cloning efficiency was improved by 50% in the presence of 3T3 cells. Growth did not correlate with tumor differentiation or site of origin of the tumor specimen. Culture of specimens from the primary site resulted in growth significantly more frequently than culture of specimens obtained from metastatic neck nodes.

Carcinoma, Squamous Cell↗
PubMed1987

Expression of human choriogonadotropin-like material correlates with metastatic phenotype of R3230 AC rat adenocarcinoma.

Human choriogonadotropin (hCG)-like material has been found in variable amounts on the surface of cells of human and animal tumors. Intravenous injection of R3230 AC rat adenocarcinoma cells, one of the models investigated, results in multiple lung foci seeding. We analyzed the phenotypic diversity of this tumor by cloning and culturing two distinct cell subpopulations from a cell culture of this tumor, hereafter called OR or original cell culture. One was obtained after repeated exposure of the OR to increasing concentrations of concanavalin A and wheat germ agglutinin. A single clone was isolated and was named lectin-resistant (LR) cell line. The LR cells did not metastasize but maintained stable tumorigenicity and morphology over at least 10 passages. A second cell line was obtained by repeated passage and injection of cells from a single metastatic node. After repeating the process five times, a single clone of cells was selected from the final variant and was called lung metastatic (LM) cell line. The LM cultured cells maintained stable tumorigenicity, morphology, and metastatic properties for no more than 10 passages. OR, LR, and LM cells were assessed by their doubling time (DT), chromosome counts, and hCG immunocytochemistry. The results demonstrated that the LM cell line had a higher chromosome count than the LR and the OR cell lines, and its DT was the shortest. Immunocytochemistry of the transplanted OR neoplasm showed scattered expression of the hCG-like material. By the same techniques a complete lack of reactivity of the LR cells was found. However, almost all cells of the LM line were strongly positive for hCG-like material. After a few passages, the great majority of the LM cells also became unreactive. Our data demonstrate: (i) the existence of marked heterogeneity of the expression of hCG-like material in the primary tumor cell population; (ii) that the expression of hCG-like material correlates with the metastasizing capacity of the cells; and (iii) that there is a phenotypic instability for the expression of hCG-like material by tumor cells when maintained in vitro.

Adenocarcinoma↗
PubMed1986

Limb-salvage procedures for osteosarcoma. An alternative to amputation.

Amputation remains the standard surgical treatment for patients with osteosarcoma. However, in carefully selected patients, eradication of the primary lesion can be achieved by en bloc resection of the affected bone. Between 1963 and 1984, 77 patients with osteosarcoma of the extremity were seen. Forty-six patients were managed with combined treatment which included preoperative chemotherapy, operation and postoperative adjuvant chemotherapy between 1968 and 1984. We report the 11 patients in this group who underwent limb-salvage procedures.

Adolescent↗
PubMed1986

Carpal tunnel syndrome caused by aberrant lumbrical muscles associated with cystic degeneration of the tenosynovium: a case report.

A 7-year-old boy who suffered from carpal tunnel syndrome caused by aberrant lumbrical muscles associated with cystic degeneration of the tenosynovium of the left hand is described. Judging from the literature studied, this seems to have a very rare origin. Symptoms subsided, and no recurrence has been noticed after operative removal of these structures.

Carpal Tunnel Syndrome↗
PubMed1985

Malignant bone and soft-tissue tumor and HLA.

Certain HLA antigens have been found to possess positive associations with a number of disease. Weak associations have been recognized for a number of malignancies. In our present study, we contemplated unraveling the relationship between HLA antigens and malignant bone and soft-tissue tumor. A homogeneous group of thirty Japanese patients underwent tissue-typing for the expression of HLA-A, B, DR and DQ antigens. Significant increases were noted in the frequencies of HLA-A 26, B 39 and DR blank antigens. When these subjects were subdivided into two groups according to their age of onset, the frequencies of HLA-A 26 and B 39 were noticed to be increased among the juvenile group only. Frequency of HLA-DR blank was increased in both groups. The frequency of HLA-B 12 was observed to be increased among those and especially in the juvenile group who developed pulmonary metastases within one year after initiation of treatment. Half of the ten poor prognosis cases carried this antigen. The etiological and prognostic significance of these findings remain to be determined.

Age Factors↗
PubMedDate not supplied

Immunohistochemical determination of P-glycoprotein in a rat mammary tumour treated with tamoxifen.

The effect of treatment with the antiestrogen Tamoxifen on the distribution and localization of P-glycoprotein was determined by immunohistochemistry in a rat mammary tumour model, the R3230AC. Both in the untreated and the treated tumours, P-glycoprotein is unevenly expressed with numerous negative tumour cells and located predominantly in the cytoplasmic membranes. Administration of Tamoxifen significantly lowers P-glycoprotein content of the tumour studied.

ATP Binding Cassette Transporter, Subfamily B, Mem↗