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Biomedical subjects

C C Huang

Publications and source records attributed to C C Huang.

At least 217 records · Page 12Linked to original sources
PubMed1998

Vertical root fracture in nonendodontically treated teeth--a clinical report of 64 cases in Chinese patients.

Vertical root fractures (VRFs) in teeth without endodontic treatment are uncommon. A clinical study was done on 64 cases of VRFs in 61 Chinese patients to define better the clinical characteristics, diagnostic signs, and possible causes. Results showed that fractures occurred most often in first molars of patients between 40 and 69 yr of age, and the incidence was two times higher in males than in females. Flat roots with smaller mesiodistal diameters were more prone to fracture. The majority (79%) of patients had intact dentition with less than four teeth missing. Fractured teeth were frequently attrited with no restorations. VRFs may result from excessive or repetitive masticatory force due to damaging chewing habits exerted on flat roots of smaller mesiodistal diameter. Nonendodontic VRFs seem to occur more frequently than earlier believed and may represent an underdiagnosed clinical entity deserving of our attention.

Adult↗
PubMed1998

T-cell receptor repertoires utilized in response to linear peptides representing an immunodominant MHC class II restricted T-cell epitope are far more diverse than that utilized in response to the same epitope in the nominal antigen.

Previous analyses of the T-cell receptor (TCR) repertoire utilized in response to the 1-102 fragment of the lambda cI repressor protein and specific for the immunodominant amino acid 12-26 region in the context of I-Ek, have shown this repertoire to be extremely restricted. In contrast, here we show that the TCR repertoires utilized in two strains of I-Ek expressing mice in response to two linear peptides representing this immunodominant region are diverse. Despite their extensive diversity, these repertoires are somewhat overlapping. In addition, structural similarities were observed between the full lambda cI fragment (1-102) and peptide elicited TCR repertoires, including frequent use of the Valpha2 family of gene segments, particularly among peptide (12-26) elicited TCRs cross-reactive with 1-102/I-Ek. Nevertheless, these data indicate that it may be difficult to mimic the immune response to an immunodominant epitope of a protein antigen via immunization with linear peptides containing the amino acid sequence of that epitope. Possible explanations for differences in the levels of TCR diversity among T cells responding to an epitope present in a nominal antigen as compared to T cells responding to linear peptide antigens containing this same epitope are discussed.

Amino Acid Sequence↗
PubMed1998

Expression of annexin II in human middle ear cholesteatoma.

Annexin II has previously been discovered to have involvements in DNA replication and metabolism, bone resorption, and osteoclast formation. In our work, Western blotting and immunohistostaining studies revealed the presence of annexin II in human cholesteatoma tissue. With monoclonal mouse antiannexin II antibody, a 36,000 dalton protein (annexin II) was identified in the cholesteatoma protein extract. Immunoalkaline-phosphatase staining selectively localized annexin II to the keratinocytes in the basal and spinous layers of the cholesteatoma tissue. In normal human skin, annexin II is expressed mainly in the cytoplasmic membrane of its keratinocytes in the basal layer without significant staining in its nucleus. However, annexin II is expressed in both the cytoplasmic membrane and the nucleus of the keratinocytes in basal and spinous layers of human cholesteatomas. Our findings indicate a possible physiologic role of annexin II in keratinocyte cell hyperproliferation during development of human cholesteatoma.

Adult↗
PubMed1998

The lips. Excision and repair.

Dermatologists commonly encounter lesions arising on the lips that require excision either for biopsy or treatment. Several surgical techniques used for excision and repair of the lip in the treatment of these conditions are reviewed. Topics covered include the importance of the lip, lip anatomy as it pertains to cutaneous surgery, techniques for obtaining lip anesthesia, partial-thickness and full-thickness lip excision and repair, surgical vermilionectomy, and carbon dioxide laser vermilionectomy. Emphasis will be placed on those surgical techniques that might commonly be used in a general dermatology practice.

Esthetics↗
PubMed1998

Effects of an educational program on parents with febrile convulsive children.

The purpose of this study was to characterize the effects of an educational program on knowledge, attitude, concern, and first-aid measures among parents with febrile convulsive children. All parents completed a pretest questionnaire 3 weeks before the meeting. The parents were assigned randomly into experimental (n = 65) and control (n = 64) groups on the day they attended the program. The control group completed the identical questionnaire (posttest) before the program, whereas the experimental group completed the same posttest after the program. In pretest, most parents considered electroencephalogram or computed tomography necessary in evaluating their children, suggested that immunization be postponed, and rated the risk of subsequent epilepsy as high for their children. Most of them favored frequent body temperature measurement, were very anxious about further febrile convulsion episodes during the night, and were fever phobic. After education, although only a slight change in fever anxiety was found, the experimental group showed significant improvement in knowledge, attitude, concerns, and anticipatory practice of febrile convulsion compared with the control group. In conclusion the parents' poor knowledge, negative attitudes, anxiety, and inadequate first-aid measures toward febrile convulsion can be effectively improved by an educational intervention program.

Analysis of Variance↗
PubMed1998

Risk factors analysis for early fatality in children with acute bacterial meningitis.

To identify the cause of early fatality and to delineate the clinical findings on admission associated with this early fatality, a retrospective study of 101 children with bacterial meningitis was performed in southern Taiwan. Risk factors for early fatality are compared between patients with and without acute death in the first 3 days after admission. The overall patient fatality is 27%. Eighty-five percent of them (23 patients) occur at an average of 16.5 hours after admission despite proper antibiotic treatment. The causes of early death are predominantly hemodynamic in 14 patients (61%) and predominantly neurologic in nine (39%). Analysis of clinical parameters available on admission indicated a significant risk of early death in patients who have tachycardia, tachypnea, hypothermia, poor skin perfusion, metabolic acidosis, leukopenia, thrombocytopenia, low cerebrospinal fluid leukocyte count, and high cerebrospinal fluid lactate level. Multivariate analysis demonstrates that metabolic acidosis, poor skin perfusion, and low cerebrospinal fluid leukocyte count are independently and significantly associated with early fatality. In conclusion, two thirds of early fatalities in children with bacterial meningitis are the result of septic shock. Close surveillance for signs of septic shock, as well as of brain herniation should be continued, especially within 3 days after antibiotic treatment.

Acute Disease↗
PubMed1998

Oxygen, arterial blood gases and ventilation are unchanged during dialysis in patients receiving pressure support ventilation.

This study was undertaken to observe whether dialysis-induced alveolar hypoventilation and arterial hypoxaemia occur during bicarbonate haemodialysis in patients receiving partial mechanical support with pressure support ventilation. Nineteen patients admitted to the medical intensive care unit requiring mechanical ventilation and haemodialysis were enrolled. Arterial blood gas, white blood cell (WBC) count, minute ventilation, respiratory rate, breathing pattern and blood pressure were measured according to the following time schedule: pre-dialysis (time 0), and at 15, 30, 60, 120, 180, 240 min thereafter. Results showed that, with the use of cuprammonium dialyser, the WBC count dropped immediately and reached the nadir 15 min after haemodialysis. Thereafter, it recovered and overshot the pre-dialysis values until the end of dialysis. The bicarbonate dialysate indeed resulted in rapid and significant metabolic alkalosis. However, no decrease of PaO2 occurred throughout haemodialysis. The tidal volume, minute ventilation and breathing pattern remained stable during haemodialysis. We conclude that neither dialysis-induced alveolar hypoventilation nor arterial hypoxaemia developed during bicarbonate dialysis in patients mechanically ventilated with the pressure support ventilation.

Adult↗
PubMed1998

Amyloid formation by mutant huntingtin: threshold, progressivity and recruitment of normal polyglutamine proteins.

Huntington's disease (HD) is caused by an expanded CAG trinucleotide repeat encoding a tract of consecutive glutamines near the amino terminus of huntingtin, a large protein of unknown function. It has been proposed that the expanded polyglutamine stretch confers a new property on huntingtin and thereby causes cell and region-specific neurodegeneration. Genotype-phenotype correlations predict that this novel property appears above a threshold length (approximately 38 glutamines), becomes progressively more evident with increasing polyglutamine length, is completely dominant over normal huntingtin and is not appreciably worsened by a double genetic dose in HD homozygotes. Recently, an amino terminal fragment of mutant huntingtin has been found to form self-initiated fibrillar aggregates in vitro. We have tested the capacity for aggregation to assess whether this property matches the criteria expected for a fundamental role in HD pathogenesis. We find that that in vitro aggregation displays a threshold and progressivity for polyglutamine length remarkably similar to the HD disease process. Moreover, the mutant huntingtin amino terminus is capable of recruiting into aggregates normal glutamine tract proteins, such as the amino terminal segments of both normal huntingtin and of TATA-binding protein (TBP). Our examination of in vivo aggregates from HD post-mortem brains indicates that they contain an amino terminal segment of huntingtin of between 179 and 595 residues. They also contain non-huntingtin protein, as evidenced by immunostaining for TBP. Interestingly, like the in vitro aggregates, aggregates from HD brain display Congo red staining with green birefringence characteristic of amyloid. Our data support the view that the expanded polyglutamine segment confers on huntingtin a new property that plays a determining role in HD pathogenesis and could be a target for treatment. Moreover, the new property might have its toxic consequences by interaction with one or more normal polyglutamine-containing proteins essential for the survival of target neurons.

Adult↗
PubMed1998

Aminoguanidine reduces glomerular inducible nitric oxide synthase (iNOS) and transforming growth factor-beta 1 (TGF-beta1) mRNA expression and diminishes glomerulosclerosis in NZB/W F1 mice.

Over-expression of iNOS is implicated in the pathogenesis of glomerulonephritis in animal models of systemic lupus erythematosus. The aim of this study was to evaluate the effect of aminoguanidine, a selective inhibitor of iNOS, for the protection from glomerulosclerosis in NZB/W F1 mice. Female NZB/W F1 mice (n = 8) were treated with aminoguanidine (1 g/l) in drinking water for 4 months starting at age 2 months before the onset of glomerulonephritis. Controls were age- and sex-matched mice (n = 10) without aminoguanidine treatment. By glomerular microdissection and reverse-transcription competitive polymerase chain reaction, we found that glomerular iNOS/beta-actin and TGF-beta1/beta-actin mRNA ratios were reduced 15.1% (P<0.05) and 61.3% (P<0.01), respectively, in aminoguanidine-treated mice. Aminoguanidine significantly reduced the glomerular iNOS staining, urinary nitrite production and degree of glomerulosclerosis. In addition, the glomerular volume and mean glomerular cell number were reduced 33.2% (P<0.01) and 32.8% (P<0.01), respectively. Likewise, the urinary proteinuria was also significantly reduced by aminoguanidine. These results indicate that administration of aminoguanidine may reduce the progression of glomerulosclerosis in NZB/W F1 mice, possibly through inhibition of glomerular nitric oxide production.

Animals↗
PubMed1998

The role of acetic acid in the prevention of salt-induced aggregation of snake venom cardiotoxins.

Snake venom cardiotoxins (CTXs) exhibit a strong tendency to aggregate upon desalting and hence it is extremely difficult to prepare salt-free cardiotoxin(s). In the present study, we describe a new method for preparation of salt-free CTX based on dialysis against acetic acid. Based on experimental observation and the three dimensional solution structure of cardiotoxin analogue III from the Taiwan cobra (Naja naja atra), a molecular mechanism for the prevention of aggregation of cardiotoxins by acetic acid is discussed. In our opinion, the results obtained in the present study would pave way for elucidating the structural basis for the broad spectrum of biological activities exhibited by snake venom cardiotoxins.

Acetic Acid↗