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Biomedical subjects

H P Huang

Publications and source records attributed to H P Huang.

At least 19 recordsLinked to original sources
PubMed2003

Immunoglobulin levels in Bull terriers suffering from lethal acrodermatitis.

An enzyme-linked immunosorbent assay, developed by one the authors (Huang, 1993) was used to measure immunoglobulin levels in previously stored plasma samples from eight dogs suffering from lethal acrodermatitis (LAD) and 10 normal Bull terriers. The aim of the study was to document plasma immunoglobulin levels and to determine if dogs suffering from LAD had low IgA levels. The results showed that dogs suffering from LAD had normal IgG and IgM levels but significantly lower IgA levels than the control group. This finding may in part explain the frequent occurrence of microbial infections recorded in dogs suffering from LAD.

Acrodermatitis↗
PubMed2001

Tbx19, a tissue-selective regulator of POMC gene expression.

Pituitary cell types arise in a temporally and spatially specific fashion, in response to combinatorial actions of transcription factors induced by transient signaling gradients. The critical transcriptional determinants of the two pituitary cell types that express the pro-opiomelanocortin (POMC) gene, the anterior lobe corticotropes, producing adrenocorticotropin, and the intermediate lobe melanotropes, producing melanocyte-stimulating hormone (MSH alpha), have remained unknown. Here, we report that a member of the T-box gene family, Tbx19, which is expressed only in the rostral ventral diencephalon and pituitary gland, commencing on e11.5, marks pituitary cells that will subsequently express the POMC gene and is capable of altering progression of ventral cell types and inducing adrenocorticotropin in rostral tip cells. It is suggested that Tbx19, depending on the presence of synergizing transcription factors, can activate POMC gene expression and repress the alpha glycoprotein subunit and thyroid-stimulating hormone beta promoters.

Amino Acid Sequence↗
PubMed2000

Tumor promotion of N-nitroso-N-(3-keto-1, 2-butanediol)-3'-nitrotyramine derived from nitrosation of Maillard reaction product in CD-1 mice.

N-Nitroso-N-(3-keto-1,2-butanediol)-3'-nitrotyramine (NO-NTA) is a product of a model browning system generated in the presence of sodium nitrite. Our previous study showed that NO-NTA had genotoxicity and proved to be an initiator and promoter on mouse C3H10T1/2 cells. In this study, a two-stage skin carcinogenesis protocol was used to promote CD-1 mouse skin carcinogenesis using NO-NTA. Twice weekly, for 38 weeks, topical application of NO-NTA at the concentration of 250 nmol to mice previously initiated with benzo(a)pyrene (BaP) caused 90% tumor incidence. However, no tumors were observed in mice treated with BaP or treated with NO-NTA alone. The NO-NTA-promoted tumors that were observed histologically in mice showed well-differentiated squamous cell carcinoma with invasion into the subcutaneous region. Application of the same amount of NO-NTA not only caused significant induction of hyperplasia but also epidermal ornithine decarboxylase (ODC) activity. Treatment of mouse skin (1 cm(2)) with various amounts of NO-NTA (10, 50, or 250 nmol) caused production of hydrogen peroxide by 1.63-, 1.91-, and 2. 38-fold, respectively, and marked induction of myeloperoxidase (MPO) by 21-, 39-, and 61-fold. These results indicate that NO-NTA is a new tumor promoter and may induce tumor promotion by oxidant stress in CD-1 mouse skin.

Animals↗
PubMed2000

Regulation of the pancreatic islet-specific gene BETA2 (neuroD) by neurogenin 3.

The BETA2 (neuroD) gene is expressed in endocrine cells during pancreas development and is essential for proper islet morphogenesis. The objective of this study is to identify potential upstream regulators of the BETA2 gene during pancreas development. We demonstrated that the expression of neurogenin 3 (ngn3), an islet- and neuron-specific basic-helix-loop-helix transcription factor, partially overlaps that of BETA2 during early mouse development. More importantly, overexpression of ngn3 can induce the ectopic expression of BETA2 in Xenopus embryos and stimulate the endogenous RNA of BETA2 in endocrine cell lines. Furthermore, overexpression of ngn3 could cause a dose-dependent activation on the 1.0-kb BETA2 promoter in islet-derived cell lines. Deletion and mutation analyses revealed that two proximal E box sequences, E1 and E3, could bind to ngn3-E47 heterodimer and mediate ngn3 activation. Based on these results, we hypothesize that ngn3 is involved in activating the expression of BETA2 at an early stage of islet cell differentiation through the E boxes in the BETA2 promoter.

3T3 Cells↗
PubMed2000

[Study of EEG approximate entrophy in different brain functional states].

AIM: The approximate entrophy was applied to study EEG in different brain functional states. METHODS: EEG were recorded in 40 cases healthy volunteers, who are in five functions states (1. resting conscious with eye-close. 2. resting conscious with eye-opened. 3. closed eyes and listening pure tone. 4. staring at picture. 5. closed eyes and counting numbers). ApEn were calculated in these EEG. RESULTS: The ApEn of frontal was the highest and ApEn of occipital was the lowest in resting conscious with eye-closed. ApEn in every brain area were higher than that in resting conscious with eye-opened. ApEn were changed in different physiological functions. Variation of frontal EEG ApEn value were highest. CONCLUSIONS: The ApEn may reflect characteristic of EEG non-linear dynamical. It is a stable parameter. The dates of its requirement were fewer. It may be a useful parameter in studying EEG time series.

Adult↗
PubMed1999

Effects of ear type, sex, age, body weight, and climate on temperatures in the external acoustic meatus of dogs.

OBJECTIVE: To investigate effects of ear type, sex, age, body weight, and ambient climatic conditions on external acoustic meatus (external ear canal) temperatures in dogs. ANIMALS: 650 dogs without clinical signs of ear disease. PROCEDURE: Dogs were assigned to 5 groups on the basis of auricular conformation and amount of hair in the external ear canal and 4 groups on the basis of body weight or age. External ear canal temperatures (EECT) were measured, using an infrared thermometer. Mean EECT determined for each group were compared to evaluate effects of ear type, age, weight, and sex, and EECT measured at different ambient temperatures and humidities were compared to determine climatic effects. RESULTS: Dogs with hirsute ear canals had significantly lower EECT than dogs with hairless ear canals, whereas significant differences were not detected between dogs with erect and pendulous auricles. Dogs < 6 years old had higher EECT than older dogs, and dogs that weighed < 6 kg had lower EECT than larger dogs. External ear canal temperatures measured when ambient temperatures were < 25 C were less than those measured at warmer temperatures. Sex and relative humidity did not affect EECT CONCLUSIONS AND CLINICAL RELEVANCE: EECT of dogs without ear disease were affected by weight and age, amount of hair in the external ear canal, and ambient temperature. However, hirsute ears had lower, not higher, EECT than hairless ears, suggesting that EECT may play less of a role in the development of otitis externa than believed.

Age Factors↗
PubMed1998

Use of infrared thermometry and effect of otitis externa on external ear canal temperature in dogs.

OBJECTIVE: To compare infrared thermometry with rectal thermometry as a method of assessing core body temperature in dogs and to assess the effect of otitis externa on external ear canal temperature (EECT). DESIGN: Prospective study. ANIMALS: 650 dogs without history or clinical signs of otitis externa and 85 dogs with recurrent or chronic otitis externa. PROCEDURE: Rectal temperature was measured, using a mercury thermometer. External ear canal temperature was measured, using an infrared tympanic thermometer. RESULTS: Measurements of body temperature at the 2 sites did not agree. Sensitivity and specificity of infrared thermometry in detecting fever, as determined by rectal thermometry, were 69.7 and 84.6%, respectively. Use of methods to predict rectal temperature from EECT did not improve the accuracy of infrared thermometry. Otitis externa significantly influenced EECT. CLINICAL IMPLICATIONS: Use of infrared thermometry as a replacement for rectal thermometry in assessing core body temperature in dogs was unsatisfactory. The 2 methods for measuring body temperature were not interchangeable in dogs.

Animals↗
PubMed1998

Promotional effect of N-nitroso-N-(3-keto-1,2-butanediol)-3'-nitrotyramine (a nitrosated Maillard reaction product) in mouse fibroblast cells.

N-Nitroso-N-(3-keto-1,2-butanediol)-3'-nitrotyramine (NO-NTA) is a product of model browning system generated in the presence of sodium nitrite. The chemical structure of this compound has been confirmed by UV, mass and nuclear magnetic resonance, and infrared spectroscopy in our previous study. A two-stage transformation protocol was used to chemically transform the mouse embryo fibroblasts C3H10T1/2 cells. To initiate transformation, the cells were treated with benzo[a]pyrene (BaP) (0.1 mg/ml), and NO-NTA (0.01, 0.1 and 1 mg/ml) was employed subsequently to complete the transformation process. Malignant transformed foci were formed in BaP-initiated and NO-NTA promoted C3H10T1/2 cells after 8 wk. Cells treated with NO-NTA alone failed to induce transformation. However, cells initiated with BaP and promoted by cells initiated with BaP and promoted by NO-NTA demonstrated oncogenic properties. Cell lines transformed with NO-NTA-transformed colonies exhibited enhanced growth rate, anchorage independence and tumorigenicity in animals relative to parent cells. These results indicate that NO-NTA is a new tumour promoter and may induce tumour promotion by two-stage oncogenesis. Further studies on the mechanism of action of NO-NTA are now in progress.

Animals↗
PubMed1997

Diabetes, defective pancreatic morphogenesis, and abnormal enteroendocrine differentiation in BETA2/neuroD-deficient mice.

Candidate transcription factors involved in pancreatic endocrine development have been isolated using insulin gene regulation as a paradigm. The cell-type restricted basic helix-loop-helix (bHLH) gene, BETA2/NeuroD, expressed in pancreatic endocrine cells, the intestine, and the brain, activates insulin gene transcription and can induce neurons to differentiate. To understand the importance of BETA2 in pancreatic endocrine cell differentiation, mice lacking a functional BETA2 gene were generated by gene targeting experiments. Mice carrying a targeted disruption of the BETA2 gene developed severe diabetes and died perinatally. Homozygous BETA2 null mice had a striking reduction in the number of insulin-producing beta cells and failed to develop mature islets. Islet morphogenesis appeared to be arrested between E14.5 and E17.5, a period characterized by major expansion of the beta cell population. The presence of severe diabetes in these mice suggests that proper islet structure plays an important role in blood glucose homeostasis. In addition, secretin- and cholecystokinin-producing enteroendocrine cells failed to develop in the absence of BETA2. The absence of these two pancreatic secretagogs may explain the abnormal cellular polarity and inability to secrete zymogen granules in pancreatic acinar exocrine cells. The nervous system appeared to develop normally, despite abundant expression of BETA2 in differentiating neurons. Thus, BETA2 is critical for the normal development of several specialized cell types arising from the gut endoderm.

Animals↗
PubMed1997

Mechanism and computer simulation of a new robot hand for potential use as an artificial hand.

A prosthetic hand is essential to provide rehabilitation for individuals who lose a hand. A prosthetic hand serves two purposes: cosmetic and functional. In this paper, a prototype of the artificial hand with an emphasis on the functionality purpose is presented. A new mechanism, the NTU-Hand (NTU-Hand, patent number 107115, Taiwan, R.O.C.), which has 5 fingers with 17 degrees of freedom, has been designed and fabricated in our laboratory. Due to the special design of the mechanism, the hand has an uncoupled configuration in which each finger and joint are all individually driven. The size of the hand is almost the same as a human hand. All actuators, mechanical parts, and sensors are on the hand. The compact design makes it feasible to adapt the hand to the injured wrist. A computer simulation with three-dimensional graphics was also built to evaluate the manipulative range of the artificial hand. From the results of this simulation, the relationship between the hand and the grasped object in a specific viewpoint can be obtained.

Artificial Limbs↗
PubMed1996

Effects of dietary nucleoside-nucleotide mixture on memory in aged and young memory deficient mice.

Intestinal mucosa, bone marrow hematopoietic cells and brain have limited capacity for the de novo synthesis of nucleosides (NSs) and nucleotides (NTs). Whereas the role of dietary NS and NT in the former two tissues is known, it is not known in the brain. Therefore we studied the effect of dietary NS and NT mixture on memory in aged mice (Experiment 1) and young memory deficient mice (Experiment 2). Memory retention was studied by step-through type passive avoidance performance (maximum 180 seconds). In Experiment 1 aged (7 month old) senescence accelerated mice (SAM) were fed 20% casein diet (control) or this diet supplemented with 0.5% NS/NT mixture for 12 weeks. Memory was studied 1, 2 and 3 days after the electric shock (punishment). In Experiment 2, young (1 month old) memory deficient mice (Dull mice) and normal mice (ddY mice) were fed the same diets as those in Experiment 1 for 12 weeks. Memory retention was studied 1 and 3 days after the punishment. In the aged SAM the average time of avoidance and also the percentages of successful memory 2 and 3 days after the punishment were significantly higher in the NS/NT diet group than the control diet group (P < 0.05). In the Dull mice percentage of successful memory was higher in the NS/NT diet group than in the control group 3 days after the punishment, however, such an effect was not observed in the normal mice. These results suggest that insufficient endogenous supply of NSs and NTs may be responsible for the factor of memory deficiency with aging or of genetical memory deficiency, which can be improved by the dietary administration of NSs and NTs.

Aging↗
PubMed1996

BETA3, a novel helix-loop-helix protein, can act as a negative regulator of BETA2 and MyoD-responsive genes.

Using degenerate PCR cloning we have identified a novel basic helix-loop-helix (bHLH) transcription factor, BETA3, from a hamster insulin tumor (HIT) cell cDNA library. Sequence analysis revealed that this factor belongs to the class B bHLH family and has the highest degree of homology with another bHLH transcription factor recently isolated in our laboratory, BETA2 (neuroD) (J. E. Lee, S. M. Hollenberg, L. Snider, D. L. Turner, N. Lipnick, and H. Weintraub, Science 268:836-844, 1995; F. J. Naya, C. M. M. Stellrecht, and M.-J. Tsai, Genes Dev. 8:1009-1019, 1995). BETA2 is a brain- and pancreatic-islet-specific bHLH transcription factor and is largely responsible for the tissue-specific expression of the insulin gene. BETA3 was found to be tissue restricted, with the highest levels of expression in HIT, lung, kidney, and brain cells. Surprisingly, despite the homology between BETA2 and BETA3 and its intact basic region, BETA3 is unable to bind the insulin E box in bandshift analysis as a homodimer or as a heterodimer with the class A bHLH factors E12, E47, or BETA1. Instead, BETA3 inhibited both the E47 homodimer and the E47/BETA2 heterodimer binding to the insulin E box. In addition, BETA3 greatly repressed the BETA2/E47 induction of the insulin enhancer in HIT cells as well as the MyoD/E47 induction of a muscle-specific E box in the myoblast cell line C2C12. In contrast, expression of BETA3 had no significant effect on the GAL4-VP16 transcriptional activity. Immunoprecipitation analysis demonstrates that the mechanism of repression is via direct protein-protein interaction, presumably by heterodimerization between BETA3 and class A bHLH factors.

Amino Acid Sequence↗
PubMed1995

N-Nitroso-N-(3-keto-1,2-butanediol)-3'-nitrotyramine. A new genotoxic agent derived from the reaction of tyrosine and glucose in the presence of sodium nitrite.

N-Nitroso-N-(3-keto-1,2-butanediol)-3'-nitrotyramine (NO-NTA) is a product of a model browning system in the presence of sodium nitrite. In this study, the chemical structure is confirmed by spectral studies, including UV, mass spectrometry, nuclear magnetic resonance and infrared spectroscopy. NO-NTA is strongly genotoxic to the rat hepatocyte and is moderately cytotoxic to mouse C3H10T1/2 cells. Results obtained in this study indicate that NO-NTA inflicted DNA damage through the formation of a DNA adduct. In addition, C3H10T1/2 cells were treated with NO-NTA and, following addition of 12-O-tetradecanoylphorbol-13-acetate (TPA) as promotor, the increase of transformed foci indicated that NO-NTA could possibly be an initiator [corrected] of TPA tumor promotion. A transformed cell line from NO-NTA initiated and TPA promoted foci increased saturation density and growth ability in soft agar reactive to the control line. These results suggest that the formation of a genotoxic agent of nitroso-derivatives may take place in a nitrite-containing food system during processing and cooking.

Animals↗
PubMed1995

[Clinical study on acute cerebral hemorrhage with zhong feng I, II oral liquor].

The 120 patients with acute cerebral hemorrhage were divided into two groups: tested group and control group. The tested group were treated with Zhong Feng I oral liquor (acute stage), Zhong Feng II oral liquor (convalescent stage) and Western medicine, the control group were treated with Western medicine alone. The results showed that: the course of acute stage, and the time for restoring consciousness and the time for eliminating high intracranial pressure were shorter in tested group than those in control group; The mortality and rate of causing disability lowered. The rate of intracranial hemorrhage absorption was promoted in tested group (81.67%) than that in control group (58.37%), P < 0.01; The efficacy in various aspects was superior than that of control.

Acute Disease↗
PubMed1994

Mechanism of drug release from an acrylic polymer-wax matrix tablet.

An acrylic polymer-wax matrix system was evaluated for oral sustained-release tablets of diphenhydramine HCl. A desirable release profile of diphenhydramine was achieved by incorporating Eudragit L in a carnauba wax matrix. In this polymer-wax system, carnauba wax maintained the integrity of the matrix, whereas Eudragit L slowly eroded in the matrix as the drug was released. Thus, the area-to-volume ratio of the tablet remained constant over the duration of the drug release. In vitro drug release studies were conducted at physiological pHs that exist in the gastrointestinal tract. Drug release rates decreased as the polymer:drug ratio increased from 1:2 to 2:1. The drug release rate was faster in pH 7.5 phosphate buffer than in 0.1 N HCl solution. The drug release from these polymer-wax matrices is described by a combination diffusion/erosion mechanism. Based on the typical pH encountered in intestinal fluids, complete dissolution of the drug and polymer at pH 7.5 in 8-10 h would ensure good bioavailability of the drug following oral administration.

Diphenhydramine↗
PubMed1993

Effects of fatty acids on the growth and composition of Malassezia pachydermatis and their relevance to canine otitis externa.

Malassezia pachydermatis is one of the many infective agents involved in canine otitis externa. Two major phenotypes (large and small colony types), which had different fatty acid compositions, were found among strains of M pachydermatis isolated from canine ears or skin. The large-colony type contained palmitic, stearic, oleic and linoleic acids, whereas the small-colony type contained myristic, palmitic, stearic, linoleic acids and five other unidentified fatty acids. Exogenous saturated fatty acids in the medium had no effect on the growth of a large colony strain but oleic and linoleic acids were mycostatic. Adding fatty acids to the medium changed the fatty acid composition of the strain. Saturated fatty acids were incorporated as such into the cell, but the unsaturated fatty acids caused complex changes in composition, including the appearance of a new fatty acid. It is suggested that these changes in the fatty acid composition of M pachydermatis could explain the mycostatic effect of unsaturated fatty acids like oleic and linoleic acids at least in vitro.

Animals↗