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Biomedical subjects

G Huang

Publications and source records attributed to G Huang.

At least 181 records · Page 10Linked to original sources
PubMed1996

[Detection of severity of coronary stenosis by quantitative myocardial tomography with Tc-99m-MIBI at rest].

To evaluate the role of myocardial tomography with Tc-99m-MIBI (MB) in detecting abnormal coronary arteries, 34 patients with myocardial infarction underwent resting quantitative SPEC with MB and coronary arteriography within one month. When segmental MB uptake was < 560% of the left ventricular peak activity, there was 88% probability that a totally occluded or severely stenosed coronary artery (stenosis > 90%) was involved. There was 82% probability of finding no significant stenosis of coronary arteries in the normal myocardial segments. In the myocardial segments supplied by occluded coronary arteries, there was significantly higher MB uptake in the segments with good collateral circulation as compared with those subtended by a vessel totally occluded with poor collateral circulation (P < 0.05). The sensitivity and specificity of detecting abnormal coronary artery by quantitative analysis of myocardial tomography was 87% and 90% respectively. It is suggested that quantitative analysis of myocardial tomography with MB can differentiate between myocardial segments supplied by severely stenosed and normal coronary artery and evaluate the existence of collateral circulation.

Aged↗
PubMed1996

[Histiocytosis X of the temporal bone].

Histiocytosis X (HX) is a rare disease. There are many questions and debates in its etiology, pathology, clinical type and therapy. To enhance the recognition of otolaryngologists in HX of the ear and temporal bone and the level of diagnosis and therapy, 30 years' results of 21 patients with HX of the ear and temporal bone proved by histiopathology were reviewed, 18 patients were cured (85%), 6 cases were residual of diabete insipidus and dwarfism (28%), 3 cases died (14%). The clinical classification system should be based on the extention of diseases. Surgical curettage, radiation therapy are mainstays of treatment; chemotherapy should be used in patients with aggressive and disseminate diseases and etiology of histiocytosis should be studied on immune system that potentially aid in therapy.

Adolescent↗
PubMed1996

Inhibitory effects of Acanthopanax gracilistylus saponins on human platelet aggregation and platelet factor 4 liberation in vitro.

AIM: To study the effects of Acanthopanax gracilistylus var pubescens Li saponins (AGVPS) on human platelet aggregation and platelet factor 4 (PF4) liberation in vitro. METHODS: Human platelet aggregations induced by ADP, adrenaline, and collagen were measured turbidimetrically. The aggregation curve was recorded on a platelet aggregometer and the maximal aggregation rate (ARmax), effective deaggregation rate in 5 min (DR5 min) and lag time (LT) were autocalculated by the built-in microcomputer; PF4 liberation from human platelets stimulated by ADP and collagen was determined by recording the heparin thrombin clotting time (HTCT). Thrombosis was tested by weighing the wet and dry thrombi formed in a siliconized revolving ring. RESULTS: AGVPS inhibited in vitro the ARmax with IC50 of 1.33 (95% confidence limits: 1.09-1.63, ADP-induced), 1.66 (1.54-1.79, adrenaline-induced), and 4.2 g.L-1 (0.6-29, collagen-induced). The DR5 min (on ADP-induced aggregation) and LT (collagen-induced) were also increased as well. Meanwhile, AGVPS 0.63-2.50 g.L-1 prolonged HTCT on ADP- and collagen-stimulated PF4 liberation. At 0.34-1.39 g.L-1, AGVPS reduced the wet and dry weight of thrombi formed in vitro. CONCLUSION: AGVPS inhibits human platelet aggregation, liberation, and thrombosis in vitro, suggesting its possible antithrombotic action in man.

Adult↗
PubMed1995

Autopsy case report of a rare acute iatrogenic water intoxication with a review of the literature.

This paper reports a rare autopsy case, a 21-years old healthy female worker, who died of acute iatrogenic water intoxication after she had swallowed powder scraped off 17 matches in an apparent suicide attempt. Gastric lavage was performed as she was wrongly considered to have taken poison containing phosphorus. She was given 7.8 1 water within 2 h. The pathological findings and 16 cases from the literature between 1978-1994 are reviewed.

Adult↗
PubMed1995

The trinucleotide repeat sequence d(GTC)15 adopts a hairpin conformation.

The structure of a single-stranded (ss) oligonucleotide containing (GTC)15 [ss(GTC)15] was examined. As a control, parallel studies were performed with ss(CTG)15, an oligonucleotide that forms a hairpin. Electrophoretic mobility, KMnO4 oxidation and P1 nuclease studies demonstrate that, similar to ss(CTG)15, ss(GTC)15 forms a hairpin containing base paired and/or stacked thymines in the stem. Electrophoretic mobility melting profiles performed in approximately 1 mM Na+ revealed that the melting temperature of ss(GTC)15 and ss(CTG)15 were 38 and 48 degrees C respectively. The loop regions of ss(GTC)15 and ss(CTG)15 were cleaved by single-strand-specific P1 nuclease at the T25-C29 and G26-C27 phosphodiester bonds respectively (where the loop apex of the DNAs is T28). Molecular dynamics simulations suggested that in ss(GTC)15 the loop was bent towards the major groove of the stem, apparently causing an increased exposure of the T25-C29 region to solvent. In ss(CTG)15 guanine--guanine stacking caused a separation of the G26 and C27 bases, resulting in exposure of the intervening phosphodiester to solvent. The results suggest that ss(GTC)15 and ss(CTG)15 form similar, but distinguishable, hairpin structures.

Base Sequence↗
PubMed1995

Assessment of myocardial perfusion and viability with technetium-99m methoxyisobutylisonitrile and thallium-201 rest redistribution in chronic coronary artery disease.

We compare thallium-201 rest redistribution and fluorine-18 fluorodeoxyglucose ([18F]FDG) for the assessment of myocardial viability within technetium-99m methoxyisobutylisonitrile (MIBI) perfusion defects in 27 patients with chronic stable coronary artery disease. The following studies were performed: (1) stress 99mTc-MIBI, (2) rest 99mTc-MIBI, (3) 201Tl rest-redistribution single-photon emission tomography, (4) [18F]FDG positron emission tomography. The left ventricle was devided into 11 segments on matched tomographic images. The segment with the highest activity at stress was taken as the reference (activity=100%). Perfusion defects at 99mTc-MIBI rest were classified as severe (activity<50%), moderate (activity 50%-60%) or mild (activity 60%-85%). Uptakes of [18F]FDG and rest-redistributed 201Tl were recognized as significant if they exceeded 50% of that in the reference segment. Among the 33 segments with severe 99mTc-MIBI rest perfusion defects, 21 had significant [18F]FDG and 10 significant rest-redistributed 201Tl uptake. As regards the 37 segments with moderate defects, [18F]FDG was present in 29 and 201Tl in 31, while of the 134 segments with mild defects, 128 showed [18F]FDG uptake, and 131, 201Tl uptake. In conclusion, there is an inverse relationship between the severity of 99mTc-MIBI perfusion defects and the uptake of rest-redistributed 201Tl and [18F]FDG. Both tracers are adequate markers of viability in mild and moderate defects; in severe defects 201Tl might underestimate the presence of viability as assessed by [18F]FDG.

Adult↗
PubMed1995

Asymmetric fan transmission CT on SPECT systems.

For proper attenuation correction of SPECT images, a set of 3D attenuation maps specific to the imaging slices is needed. Among the many different approaches for deriving the attenuation maps, fan beam transmission CT (FBTCT), performed on the same SPECT system as emission imaging, has many promising and clinically practical features. The major problem of FBTCT is that the current SPECT systems do not have a large enough field of view (FOV) to cover the typical cross-sectional size of patients. To address this problem, we have developed a novel asymmetric fan (AsF) sampling scheme to extend the FOV to practical sizes for clinical TCT imaging on existing SPECT systems. This AsF scheme samples only half of the intended FOV in each projection; the other half would be sampled in an opposing projection after detector rotation. We have implemented the AsF sampling on a three-head SPECT system through a specially designed source-collimator assembly. We have modified the conventional convolution backprojection algorithm to facilitate simple and fast image reconstruction. The feasibility of the approach is confirmed by the quality of the derived TCT images of various phantoms and human subjects. The AsF sampling scheme could also have applications in other general transmission CT systems.

Biophysical Phenomena↗
PubMed1995

Calcium activates serum response factor-dependent transcription by a Ras- and Elk-1-independent mechanism that involves a Ca2+/calmodulin-dependent kinase.

Enhanced levels of cytoplasmic Ca2+ due to membrane depolarization with elevated levels of KCl or exposure to the Ca2+ ionophore ionomycin stimulate serum response element (SRE)-dependent transcription in the pheochromocytoma cell line PC12. By using altered binding specificity mutants of transcription factors that bind to the SRE, it was demonstrated that in contrast to treatment with purified growth factors, such as nerve growth factor, the serum response factor (SRF), but not Elk-1, mediates Ca(2+)-regulated SRE-dependent transcription. Enhanced levels of cytoplasmic Ca2+ were found to trigger SRE-dependent transcription via a Ras-independent signaling pathway that appears to involve a Ca2+/calmodulin-dependent kinase (CaMK). Overexpression of a constitutively active form of CaMKIV stimulated SRF-dependent transcription. Taken together, these findings indicate that SRF is a versatile transcription factor that, when bound to the SRE, can function by distinct mechanisms and can mediate transcriptional responses to both CaMK- and Ras-dependent signaling pathways.

Animals↗
PubMed1995

[Analysis of pressure-volume-hysteresis in rabbit].

UNLABELLED: The pressure-volume (PV) relationships of respiratory, lung and chest wall (Prs-V, PL-V and Pcw-V) were studied in 11 white rabbits. The relaxation pressure induced by Hering-Breuer reflex was measured on inflating certain volume of air. Four groups of inflation experiments were performed in each rabbit. (1) Inflations of incremental tidal air with 10 ml in each increment were performed from functional residual capacity (FRC) to 70 ml, then inflations of decremental tidal air with 10 ml in each decrement were done from 70 ml to FRC. (2) 70 ml of air was inflated just before each incremental and decremental inflation. (3) 10 ml more air was inflated before each predicted incremental inflation. (4) The first group inflation was repeated. THE RESULTS: The P-V curves showed a "S" shape in all 4 groups. There was an obvious hysteresis on the Prs-V and PL-V curves in the 1st group between the incremental and decremental inflations; it disappeared in the 2nd and 3rd groups. Hysteresis reappeared in the 4th group, but it was smaller than that in the 1st group. These results substantiate the theory proposed by Frazer that pulmonary hysteresis mainly comes from sequential opening and closing of lung units during inflation and deflation.

Animals↗
PubMed1995

[A study of c-src gene express product pp60c-src in esophageal carcinoma].

Using the specific monoclonal antibody of c-src gene express product, pp60c-src (McAb 327), we studied immunohistochemically in this experiment 35 cases of the esophageal squamous cell carcinomas and 22 adjacent carcinoma tissues. The positive rates of pp60c-src in the squamous cell carcinomas of the esophaguses, the proliferative and the normal squamous epithelis adjacent to the carcinoma were 65.7% (23/35), 100.0% (15/15), and 57.1% (4/7), respectively. There was significant difference among them statistically (P < 0.05). And the express amount of pp60c-src in the esophageal squamous cell carcinoma was higher than those in the proliferative and normal squamous epithelia adjacent to the carcinoma. The positive rates of pp60c-src of the esophageal squamous cell carcinoma with different differentiation grades I, II and III were 80.0% (8/10), 68.4% (13/19), and 33.3% (2/6), respectively. No significant difference was found among them statistically (P > 0.05). The higher the differentiation grade of the esophageal squamous cell carcinoma, the more the express amount of pp60c-src (P < 0.005). The results suggested that the activation and express of c-src gene be associated with the initiation and development of the esophageal squamous cell carcinoma; the express amount of pp60c-src increased in the process and was associated with the differentiation of esophageal squamous cell carcinoma.

Antibodies, Monoclonal↗
PubMed1995

[Clinical study on the feasibility of preserving vagal trunks in the surgical treatment of carcinoma of the thoracic esophagus].

The results of preserving vagal trunks in the surgical treatment of 47 patients with the carcinoma of the thoracic esophagus were discussed through a controlled study. There were 20 patients in the test group with vagus nerve being preserved (PG) and 27 in the control group (CG) with vagus nerve being routinely severed. Eighteen patients in PG and 26 in CG underwent radical resections, the remaining patients received palliative surgery. Pathological findings showed that 3 cases (15.0%) in PG and 3 cases (11.1%) in CG had cancerous invasion near the vagal trunks and/or their main branchs close to the primary cancer; and 1 case (5.0%) in PG and 3 (11.1%) in CG the vagal nerves were actually invaded by cancer cells. Determinations of basal gastric acid output (BAO) and half gastric emptying time (T 1/2) revealed that the mean value of BAO (1.93mmol/h) and T 1/2(63.51min.) of the PG were statistically different from those of 0.75mmol/h and > 105min. in CG, but similar to those of the healthy group and the preoperative control values. We consider that it is feasible to preserve vagal trunks in the operation and is beneficial in minimizing of postoperative disturbances of gastric acid output and gastric motility; but the indications of this procedure should only be limited to T1-T2 lesions in order not to jeopardize the radicality of tumor resection.

Adult↗
PubMed1995

[Aspergillosis of the larynx].

Aspergillosis of the larynx is extremely rare. Six cases of aspergillosis of the larynx were presented. Clinical characters of the patients were as follows: (1) their physical conditions were excellent: (2) Hoarsenes was the first symptom; (3) true vocal cord demonstrated white mass; (4) Biopsy of the lesion revealed suppurative, granulomatous and necrotic inflammation with hyphae and spore with in the tissue; (5) Culture of fungi displayed tobaco colour colonies of aspergillus. microscopic examination demonstrated spore and septate hyphae with coral-shape dichotomous banching and flask-shape vesicle with phialide and spore on top; (6) All patients were cured with Ketoconazol and Itraconazol without recurrence for long-term follow-up. Etiology, diagnosis and therapy of aspergillosis of the larynx were discussed.

Adult↗
PubMed1995

[Estimation of configuration of F-V curve with tangent time constant and mechanism involved].

The tangent time constants (tau t) of high, middle and low lung volumes tau t75, tau t50 and tau t25 were calculated with IBM PC/XT computer from the maximal expiratory flow volume (MEFV or F-V) curves of 1270 normal adolescent, middle-aged and old persons (age from 6 to 79). In the adolescents magnitude of tau t75 > 1s, and tau t75 > tau t50 > tau t25 reflected that the F-V curve had a round top and concaved towards the volume axis. In the old persons magnitude of tau t75 < 1s and tau t75 > tau t50 < tau t25 caused the curve to have a peak-shape top with its tail convex to the volume axis. In the middle-aged persons the indices were found to be intermediate between the adolescent and old persons. The configuration of F-V curve reflected by tau t was correspondent to that reflected with slope ratio (SR) by mead. The appearance of the peak-shape top on the F-V curve in the old persons was due to the reduced elasticity and increased collapsibility of the central airway. According to the wave-speed theory, the choke point (CP) occurs firstly at the least cross-sectional area of the collapsed trachea, then V75 is limited and decreases rapidly, and makes tau t75 < 1, so that a peak-shape top is developed on the F-V curve. The convex of the tail of F-V curve to the volume axis in the old persons is chiefly due to the reduced supporting force to the small airways and the decrease in the lung elastic recoil with aging. This leads to an increase in resistance and decrease in V25. Therefore, V25 can only descend slowly to the zero at RV, and tau t25 is elongated, so that the tail of the F-V curve is convex to the volume axis.

Adolescent↗
PubMed1995

Analysis of C-Ha-ras gene amplification and mutation in laryngeal carcinoma.

In order to study the altered molecular events during laryngeal carcinogenesis and elucidate the role of Ha-ras oncogene amplification and mutation, we have examined their profile by polymerase chain reaction (PCR) and selective oligonucleotide hybridization. We analyzed the mutational status of codon 12 of Ha-ras in 22 laryngeal carcinomas and 10 normal tissues, and found that 7 of 22 laryngeal carcinomas contained a Ha-ras mutation at codon 12. The frequency of mutation was 32%. None of the normal tissues revealed mutation. Moreover, no amplification was found in cancers when compared to the normal. Our findings indicated that the activated Ha-ras gene existed in laryngeal carcinoma, and activation of the Ha-ras gene by mutation at codon 12 might play a key role in laryngeal carcinogenesis.

Carcinoma, Squamous Cell↗
PubMed1995

[Application of the wave-speed theory to analysis of mechanical mechanism for configuration of F-V curve in normal humans].

F-V curves were performed in 572 normal male and female adolescents with DFM-86 flow-volume recorder as well as 262 normal male and female adults with LR-80 flow-volume recorder. The mechanical mechanism for the formation of the configuration in normal F-V curves was analysed with the wave-speed theory. The configurations of F-V curves were classified into 4 types, i.e. the plateau, linear, convex and concave types. The plateau type was characterized by: (1) a fast descent just after the peak; (2) a subsequent slow descending plateau; (3) the second fast descent forming a bump or knee; (4) lastly a slow descending tail, possibly with small bumps. The other 3 types were considered as variations of the plateau type. The mechanical mechanism for the formation of the plateau type was chiefly analysed with the wave-speed theory. Our investigation suggested that previous studies on the F-V curve configuration in models and animals with the wave-speed theory could be extended to the exploration in human beings.

Adolescent↗
PubMed1995

[The effect of serum glucose level on acute cerebral infarction].

The relationship between the serum glucose level and the cerebral infarct size, neurological deficits, morbidity outcome, complications and mortality was investigated in 198 acute cerebral infarction patients confirmed by computerized tomography. The results suggested that patients with hyperglycemia had larger infarct size, more neurological deficits, worse morbidity outcome, more complications and higher mortality than their normoglycemic counterparts. Our findings indicated that the elevated blood glucose level in most of the patients with cerebral infarction may be a stress response or a marifestation of latent diabetes. We considered that the hyperglycemia was a factor aggravating cerebral infarction and enhancing the degree of neurological deficit and morphological brain damage. The authors are of the opinion that insulin administration be advised in acute cerebral infarction patients with hyperglycemia so as to prevent further deterioration and improve the outcome.

Acute Disease↗