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Biomedical subjects

M C Huang

Publications and source records attributed to M C Huang.

At least 55 records · Page 3Linked to original sources
PubMed1997

Characterization of an ADP-ribosylation factor-like 1 protein in Saccharomyces cerevisiae.

ADP-ribosylation factors (ARFs) are highly conserved approximately 20-kDa guanine nucleotide-binding proteins that enhance the ADP-ribosyltransferase activity of cholera toxin and are believed to participate in vesicular transport in both exocytic and endocytic pathways. Several ARF-like proteins (ARLs) have been cloned from Drosophila, rat, and human; however, the biological functions of ARLs are unknown. We have identified a yeast gene (ARL1) encoding a protein that is structurally related (>60% identical) to human, rat, and Drosophila ARL1. Biochemical analyses of purified recombinant yeast ARL1 (yARL1) protein revealed properties similar to those ARF and ARL1 proteins, including the ability to bind and hydrolyze GTP. Like other ARLs, recombinant yARL1 protein did not stimulate cholera toxin-catalyzed auto-ADP-ribosylation. yARL1 was not recognized by antibodies against mammalian ARLs or yeast ARFs. Anti-yARL1 antibodies did not cross-react with yeast ARFs, but did react with human ARLs. On subcellular fractionation, yARL1, similar to yARF1, was localized to the soluble fraction. The amino terminus of yARL1, like that of ARF, was myristoylated. Unlike Drosophila Arl1, yeast ARL1 was not essential for cell viability. Like rat ARL1, yARL1 might be associated in part with the Golgi complex. However, yARL1 was not required for endoplasmic reticulum-to-Golgi protein transport, and it may offer an opportunity to define an ARL function in another kind of vesicular trafficking, such as the regulated secretory pathway.

ADP-Ribosylation Factors↗
PubMed1997

Expression and role of cadherins in astrocytic tumors.

Cadherins are Ca(2+)-dependent cell adhesion molecules that play an important role in tissue formation and morphogenesis in multicellular organisms. In recent years, there have been reports of cadherin involvement in tumor invasion and metastasis. Twenty-two surgical specimens and some cultured cells were studied by immunohistochemical staining. No significant difference was observed in the patients with anaplastic astrocytoma, whereas decreased expression of N-cadherin was detected at the time of recurrence in those with glioblastoma. In these groups, cerebrospinal fluid dissemination was found, and contralateral cerebral metastases and extracranial metastases were observed. We conclude that decreased N-cadherin expression at the immunohistochemically demonstrated time of recurrence correlates with tumor invasion and dissemination of cerebrospinal fluid.

Adult↗
PubMed1997

Alteration of endogenous antioxidant enzymes in naturally occurring hypertrophic cardiomyopathy.

We have recently developed a porcine model with naturally occurring hypertrophic cardiomyopathy (HCM). Similar to humans, occluded intramural coronary artery and damaged mitochondria are frequently observed in these animals in which the disease is thought to be associated with the local ischemia of myocardium. In view of antioxidant functions involved in the ischemic injury, we measured the expression of endogenous antioxidant enzymes in the tissues with and without HCM. The results showed a significant increase of Cu,Zn-superoxide dismutase (SOD), but not Mn-SOD, and decrease of catalase (CAT) activities in the various areas of HCM hearts. It was demonstrated that SOD/CAT ratios in the HCM hearts were significantly higher than those in normals and were found to be dramatically correlated with the severity of cardiac hypertrophy. The altered SOD/CAT ratio was also consistent with increase in lipid damage. We hypothesize that the elevated SOD combined with an inadequate amount of H2O2 scavenging enzyme may lead HCM heart at oxidative stress risk. However, the pathogenic role of imbalanced antioxidant enzyme needs to be further explored.

Animals↗
PubMed1997

Pregnancy with concomitant chorangioma and placental vascular malformation with mesenchymal hyperplasia.

We present two pregnancies associated with normal live births and the unusual concomitance of chorangioma and placental vascular malformation with mesenchymal hyperplasia. The enlarged placenta had the characteristic findings of chorangioma, dilated and varicose chorionic vessels and multiple vesicle-like villi containing hyaluronic acid. The vesicle-like villi showed diploid cellular DNA contents. Molecular genetic analysis using the polymerase chain reaction amplification of polymorphic microsatellite markers confirmed genetic identity among the chorangioma, the vesicle-like villi and the fetus. Both pregnancies were complicated by polyhydramnios, pre-term labour and prematurity. One neonate suffered from anaemia and thrombocytopenia. Another neonate suffered from haemangiomatosis. Our cases demonstrate that concomitant chorangioma and placental mesenchymal hyperplasia are genetically identical to the fetus and can coexist with a normal viable fetus. Since haemangiomas, chorangiomas, chorionic vessels and villi mesenchymal cells are all derived from the mesoderm, a combination of fetal haemangiomas, placental vascular malformation, chorangiomas and placental mesenchymal hyperplasia may represent a mixed form of congenital malformation of the mesoderm.

Adult↗
PubMed1996

Arachidonate and docosahexaenoate added to infant formula influence fatty acid composition and subsequent eicosanoid production in neonatal pigs.

As natural components of human milk, arachdonic and docosahexaenoic acids play important roles in neonatal development; thus, addition of these fatty acids to infant formula has been suggested. This study examined the effects of supplementation of infant formula with microbial sources of either arachidonate or docosahexaenoate or both on accretion of these fatty acids in phospholipids and subsequent modulation of eicosanoid production in neonatal pig lung. One-day-old piglets received for 25 d one of four diets (n = 5): 1) standard diet containing a fat blend similar to that of conventional infant formula, 2) diet containing 0.9 g/100 g of total fatty acids as arachidonate, 3) diet containing 0.7 g/100 g as docosahexaenoate, or 4) a diet containing both 1.0 g/100 g as arachidonate and 0.8 g/100 g as docosahexaenoate. Arachidonate supplementation resulted in 30-60% significantly greater arachidonate in lung phosphatidylethanolamine and phosphatidylcholine. In phosphatidylinositol, however, arachidonate was resistant to dietary manipulation. Accretion of docosahexaenoate in all three phospholipid classes was 2.6- to 4.7-fold greater in docosahexaenoate-supplemented groups than in the standard group. Inclusion of arachidonate in the diet augmented both prostacyclin and thromboxane production by 25 to 35%. Docosahexaenoate supplementation resulted in the least eicosanoid production among the treatments, and significant suppression was observed for thromboxane when supplementation with both fatty acids was compared with supplementation with arachidonate alone. Thus, dietary arachidonic acid and docosahexaenoic acid at concentrations only slightly greater than those found in human milk tended to exercise opposing effects on lung eicosanoid production.

Animals↗
PubMed1996

Differences in factors influencing the familial aggregation of febrile convulsion in population and hospital patients.

Socio-demographic data, initial clinical manifestations, outcome and family aggregation of febrile convulsion (FC) were compared between 85 population and 364 multicenter patients. More patients presented with clustering of seizures and had recurrence of FC in multicenter group than in population group. Multicenter patients had more fever episodes per year, more day-card attendance and a higher incidence of FC history in their parents. The odds ratio of FC in the siblings was 6:1 in population group and 12:1 in multicenter group. Lower socioeconomic status influenced the presence of FC in the sibling of population group. Instead, FC histories in the father and paternal cousins of probands had influence on the presence of FC in the siblings of multicenter group. We conclude that the population FC sample rather than the hospital sample is the more representative. And there are differences not only in the clinical manifestations but also in the effect of environmental and genetic influences on the family aggregation in population and hospital patients.

Adolescent↗
PubMed1996

[The relationship between cell proliferation activity and secretory activity in pituitary adenoma--a review of 63 cases].

Determination of the cell proliferation activity of neoplasm is useful in making a prognosis. Immunohistochemical detection using MIB-1 monoclonal antibody has recently allowed us to assess tumor cell proliferation easily, because it can be performed on paraffin-embedded specimens and the results have been demonstrated to be positively correlated with the results of PCNA staining. In this study, surgical specimens of 63 pituitary adenomas were examined by immunohistochemical staining with MIB-1 monoclonal antibody. Twenty-nine cases were non-functioning pituitary adenomas, 20 were prolactin (PRL)-producing pituitary adenomas, and 14 were growth hormone (GH)-producing pituitary adenomas. The MIB-1 positive rates of the pituitary adenomas ranged from 0% to 6.46%. In the non-functioning pituitary adenomas, the MIB-1 positive rates ranged from 0% to 4.55% (mean : 0.76%), in the PRL-producing pituitary adenomas the MIB-1 positive rates ranged 0% to 6.46% (mean : 0.91%), and in the GH-producing pituitary adenomas the MIB-1 positive rates ranged 0% to 1.28% (mean: 0.58%). There were no significant differences between these values according to the results of the Wilcoxon signed-rank test. Although the size of the non-functioning pituitary adenomas was not correlated with their MIB-1 positive rate, tumor size was closely correlated with the interval between the onset of the initial symptoms and the date of surgery. In the PRL-producing pituitary adenomas, the MIB-1 positive rate was not correlated with serum PRL levels as an index of secretory activity, but was correlated with the PRL staining positive rate. Preoperative bromocriptine therapy proved effective in reducing tumor size and serum PRL levels, but had no effect on the MIB-1 positive rate. In the GH-producing pituitary adenomas, the MIB-1 positive rate was not correlated with serum GH levels as an index of secretory activity, but was closely correlated with the GH staining positive rate. All three groups included both invasive and noninvasive tumor types, but there were no close statistical correlations between the three tumor types.

Adenoma↗
PubMed1996

A clinico-immunohistochemical study of giant cell glioblastoma.

We have reported 7 cases of giant cell glioblastoma. All cases died within 14 months despite aggressive treatment. By immunohistochemical staining, lymphocyte infiltration was found in 6 cases. GFAP and vimentin stained positive in all cases. The MIB-1 positive rate was 13.8-90% (average, 34.9%); small and mononucleated giant cells stained more than multinucleated and monstrous cells. It was concluded that this tumor can be highly malignant and its degree of malignancy is determined by the biological behavior of the mononucleated giant cells and small cells.

Adult↗
PubMed1995

Immunohistochemical and electron microscopic study of subependymal giant cell astrocytoma.

Six cases of subependymal giant cell astrocytoma (SGCA), five associated with tuberous sclerosis (TS), were reviewed by light microscopy, electron microscopy and immunohistochemistry. Histologically, all cases showed features typical of SGCA. GFAP and neurofilament expression were found in all cases. Synaptophysin and myelin basic protein were positive in single different cases. The MIB-1 positive rate was 0% in 4 cases, 3% in a case with recurrence after a partial resection, and 6.4% in another case with a rapid growing tumor. By electron microscope, glial filament was identified in the tumor cells of all cases, whereas none of them showed any ultrastructural evidence of a neuronal origin. We therefore suggest that SGCA is a glial origin tumor, arising from the astrocytic part of a subependymal nodule--the most common cerebral lesion of tuberous sclerosis caused by distorted migration of the germinal mantle-the neuronal part of which remains as entrapped remnants of dysgenetic, incompletely expressed neuronal cells.

Adolescent↗
PubMed1994

Expression of human lysozyme mRNA in the mammary gland of transgenic mice.

Owing to its inherent antimicrobial effect and positive charge, the expression of human lysozyme in bovine milk could be beneficial by altering the overall microbial level and the functional and physical properties of the milk. We have used transgenic mice as model systems to evaluate the expression of human lysozyme containing fusion gene constructs in the mammary gland. Expression of human lysozyme was targeted to the mammary gland by using the 5' promoter elements of either the bovine beta (line B mice) or alpha s1 (line H mice) casein genes coupled to the cDNA for human lysozyme. Expression of human lysozyme mRNA was not found in mammary tissue from any of line B mice. Tissues were analysed from six lines of H mice and two, H6 and H5, were found to express human lysozyme mRNA in the mammary gland at 42% and 116%, respectively, of the levels of the endogenous mouse whey acidic protein gene. At peak lactation, female mice homozygous for the H5 and H6 transgene have approximately twice the amount of mRNA encoding human lysozyme as hemizygous animals. Expression levels of human lysozyme mRNA in the mammary gland at time points representing late pregnancy, early, peak and late lactation corresponded to the profile of casein gene expression. Human lysozyme mRNA expression was not observed in transgenic males, virgin females or in the kidney, liver, spleen or brain of lactating females. A very low level of expression of human lysozyme mRNA was observed in the salivary gland of line H5.

Animals↗
PubMed1993

Diverse applications of continuous lumbar drainage of cerebrospinal fluid in neurosurgical patients.

From 1984 to 1991, continuous lumbar drainage (CLD) of cerebrospinal fluid (CSF) had been applied in 48 neurosurgical patients. Eleven of them had CSF accumulation and/or leakage at the operative sites and 37 of them suffered from CSF rhinorrhea. Successful treatment was achieved in 98% (47/48) of patients. There was neither death nor infection noted in this series. Complication was found in only one patient who developed acute subdural haematoma with pneumocephalus six days after CLD. After emergency craniotomy and evacuation of haematoma, the patient recovered without neurological deficit. The results suggest that CLD is a simple, safe and effective method in the treatment of CSF accumulation and/or leakage at the operative sites, as well as CSF rhinorrhea of various aetiologies.

Catheters, Indwelling↗
PubMed1991

Genomic organization of the human procollagen alpha 1(II) collagen gene.

The nucleotide sequence of the human procollagen alpha 1(II) collagen gene extending from within the first intron through exon 15, and part of the 15th intron has been determined. This sequence analysis (7056 bases) identifies the intron/exon organization of the region of this gene encoding the N-propeptide and part of the triple-helical domain. Structural comparison of this with the genes of other human fibrillar collagens shows considerable diversity in terms of size and number of introns and exons that encodes the N-propeptide domain. Although the genomic structure of the human procollagen alpha 1(II) gene is quite different from the rat procollagen alpha 1(II) gene, the nucleotide coding sequences are 89% identical.

Base Sequence↗
PubMed1990

Comparison and accuracy of methodologies employed for analysis of hydropathy, flexibility and secondary structure of proteins.

Various methods have been developed recently for predicting antigenic determinants in a protein by analyzing its hydropathicity, flexibility or secondary structure. The predicted results by these methods were compared directly to the observed structure of the proteins to determine how accurate they were. Regression and correlation of the predicted hydropathicity versus the observed solvent accessibility and the predicted chain flexibility versus actual mobility were determined. Three separate methods of hydropathic analysis had correlation coefficients of 0.52, 0.63 and 0.57 respectively, while a published method for chain flexibility analysis had a 0.19 correlation coefficient. Similarly, agreement between the observed and the predicted secondary structures by two methods was also determined. The limitations of these techniques were clearly defined.

Amino Acid Sequence↗
PubMed1990

Study of normal and cancerous urine using photoacoustic spectroscopy.

Photoacoustic spectroscopy (PAS) is a valuable technique, increasingly applied in clinical and biological analysis. Light absorption properties of urine and body tissue can be obtained more easily by the PAS technique because of its high sensitivity, than by the conventional optical techniques. By observing their absorption properties it is possible to diagnose some diseases and in this study we have used PAS to assess cancerous changes in urine and tissue. Three groups were studied: normal individuals; patients with cancer; and patients with cancer and subsequent inflammation; and the characteristic light absorption peaks obtained for a certain band (240-420 nm). These results were compared with the clinical diagnosis and proved consistent and reliable for the diagnosis of urinary tract cancer subsequently confirmed by operation. This method will probably be a useful tool for the early clinical diagnosis of cancer of the urinary system.

Diagnosis, Computer-Assisted↗
PubMed1989

Primary mediastinal seminoma.

Primary mediastinal seminoma is a rare neoplastic disease. Only 133 cases have been reported in the literature. Five patients with primary mediastinal seminoma had been treated at VGH from 1974 to 1986. All of them received exploratory thoracotomy but only two of them were resectable. Postoperative radiation therapy was given regardless of resection. One had additional chemotherapy due to nodal involvement. All five patients showed complete resolution and were alive and free of disease for an average follow-up period of 42.6 months (range, 5-82 months). So we conclude that mediastinal seminoma is a rare neoplastic disease and can be treated primarily by surgery. Irradiation can also induce complete remission and long term survival in those with unresectable tumors.

Adult↗
PubMed1988

Cytogenetical analysis of the germ cell in the domestic drake and mule drake.

Experiments were conducted to study the germ cell of testes in the domestic drake (Tsaiya drake) and the mule drake. The histological sections of testes of both drakes were compared in this study. The results showed that rapid testicular growth did not occur until 7 weeks of age in domestic drakes and 15 weeks of age in the mule drakes. The rate of growth of the testes and the increase in the ratio of testes weight to body weight in domestic drakes at different ages were much more rapid than in the mule drakes. However, the opposite results were found in the body weights. In the mule drakes, spermatogonia and primary spermatocytes could be observed in the seminiferous tubules, but no secondary spermatocytes, spermatids or spermatozoa in seminiferous tubules were found up to 52 weeks of age. This showed that the meiotic division had not occurred in the mule drakes. In the domestic drakes, spermatogonia in the seminiferous tubules were observed at 1 week of age. Primary spermatocytes of some males appeared as early as the third week of age. Secondary spermatocytes and spermatids in the seminiferous tubules of some drakes began to appear at 5 weeks of age as a result of the meiotic division of the spermatocytes. At 7 weeks of age, spermatids were in process of metamorphosis, and spermatozoa were first observed in the seminiferous tubules of the drake. All testes of drakes 9 weeks of age contained spermatozoa. The percentage of the seminiferous tubules containing spermatozoa increased gradually with age, and approached a plateau at 15 weeks of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗