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Biomedical subjects

Y Huang

Publications and source records attributed to Y Huang.

At least 793 records · Page 44Linked to original sources
PubMed1997

[Risk factor scoring model of STD for pregnant women in antenatal clinic].

OBJECTIVE: To develop a case finding strategy for STD among pregnant women based on risk assessment in China. METHODS: A prospective, random/double blind study of the high risk factors for STD in 1,656 pregnant women was conducted from June 1995 to February 1996. It was carried out at four Guangzhou hospitals on nine types of STD, their relative risk factor questionnaire and gynecologic examination. RESULTS: The total prevalence of six main STD was 20.89% (346/1656); No HIV and syphilis cases were found; The most common disease is cervical chlamydial trachomatis at (19.08% 316/1,656). Through statistical calculations with COX proportional hazard model, STD symptoms' high risk factors scoring system revealed the following: (1) More than one sexual partner in the preceding one year; (2) Vulvular lesion vegetation; (3) Dysusia/increased vaginal discharge; plus one of the following: 1. unemployed status; 2. sex partner unemployed; 3. age (less than 25 years of between 30-34 years of age). These six items with "three-three" scoring system can be used as a model to primary screening new STD cases using clinical data. Both sensitivity and specificity exceeded 60% (61.7% and 67.3% respectively). CONCLUSION: These are significantly better than the foreign recommended model and the scoring system in China. It is simple, convenient and applicable.

Adolescent↗
PubMed1997

Construction of mammary gland-specific expression vectors for human clotting factor IX and its secretory expression in goat milk.

Two expression vectors comprised of mouse matrix attachment regions (MARs), bovine beta-casein gene sequence, human factor IX (hFIX) minigene, and cDNA, pMCIXm and pMCIX, were constructed for the purpose of a mammary gland bioreactor. A secretory expression system of hFIX protein in milk was made using stearylamine (SA) liposome to transfect plasmid DNA directly into the mammary gland lobule of a lactating goat. The highest production of hFIX in goat milk was 13.7 ng/ml 3 days after transfection, and the hFIX production in the goat mammary gland transfected with pMCIXm containing hFIX minigene was obviously higher than that transfected with pMCIX containing hFIX cDNA. Activity immuno-analysis and the barium citrate absorption method showed that > 90% hFIX protein in milk appeared to be a gamma-glycosylated and biological activity. This result confirmed the validity of the constructed vectors for further transgenic study, and this assay could also find its success in the evaluation of a foreign gene expression and secretion in the milk as a rapid detection system using liposome to transfect DNA directly into the goat mammary gland.

Animals↗
PubMed1997

Distribution of free D-amino acids in tissues and body fluids of vertebrates.

Reports on the distribution, metabolism and origins of free D-amino acids in vertebrate tissues and body fluids are reviewed. The transient emergence of D-aspartic acid during the development of brain and peripheral organs or early stages of life is reported. D-Serine in brain is postulated to be a potentiator for the N-methyl-D-aspartate (NMDA) receptor. Some D-amino acid concentrations in human serum, such as D-Ser and D-Ala, are suggested to correlate with damage to renal function.

Alanine↗
PubMed1997

[Relationship between nm23-H1 expression and lymph node metastasis and prognosis in cervical cancer].

OBJECTIVE: To investigate the expression of nm23-H1 in cervical carcinoma and its significance. METHODS: Expression of nm23-H1 was examined by immunohistochemical method in 39 cases of adenocarcinoma and 39 cases of squamous cell carcinoma of the uterine cervix. The relationship between expression of nm23-H1 and clinic-pathologic factors and prognosis was analyzed by chi-square test. RESULTS: Positive staining rate of nm23-H1 was 44.6% in adenocarcinoma and 39.2% in squamous cell Carcinoma. The positive staining rate of nm23-H1 in stage I and II adenocarcinoma was 61.1% and 28.6% respectively (P = 0.044); in patients with recurrence nm23-H1 positive rate was lower than that in patients without recurrence (21.5% vs 56%, P = 0.39); in patients with lymph node negative, nm23-H1 positive staining was more than that in patients with lymph node positive (52% vs 28.6%), however, this difference was not statistically significant (P = 0.162). None of 14 cases of lymph node metastasis was strong positive stainig, whereas 7 of 25 without lymph node metastasis were demonstrated to have strong positive staining (P = 0.031). The 5-year survival rate in negative staining group was lower than that in the positive staining group (52.5% vs 82.4%, P = 0.042). In squamous cell carcinoma there was no statistically significant relationship between nm23-H1 expression and clinic-pathologic factors and prognosis. CONCLUSIONS: nm23-H1 expression was associated with biologic behavior in cervical adenocarcinoma.

Adenocarcinoma↗
PubMed1997

[Effect of caffeine and theophylline on Ca2+ sensitivity of troponin and Ca2+ release from SR in saponin-skinned rat cardiac muscle].

Cell membrane of cardiac muscle fiber (rat right ventricular papillary muscle) was chemically skinned (permeability of membrane increased) by treatment with saponin at low concentration (50 micrograms/ml), while the function of sarcoplasmic reticulum (SR) was preserved. The strength of rigor contraction of the skinned fiber was used as a semi-quantitative index of the ability of SR to release Ca2+. When treated with saponin at high concentration (500 micrograms/ml), both sarcolemma and membrane of SR were skinned. Tension-pCa relationship and the Ca2+ concentration required for producing 50% of maximum Ca(2+)-activated tension (pCa50) were respectively taken as qualitative and quantitative index of Ca2+ sensitivity of troponin (TN). The results showed: (1) In low saponin skinned fiber, 5 and 10 mmol/L caffeine respectively produced 89.2 +/- 12.7 and 142.5 +/- 17 mg (n = 4) rigor contraction, 5 mmol/L theophylline did not have this effect. (2) In high saponin skinned fiber 5 mmol/L theophylline, 5 and 10 mmol/L caffeine shifted the tension-pCa relationship curve to the left, pCa50 respectively increased by 0.212, 0.261 and 0.274 pCa units. These results suggest that caffeine and theophylline increase the Ca2+ sensitivity of TN and caffeine can also induce Ca2+ release from SR.

Animals↗
PubMed1997

[Postsurgical changes of the calculated wall shear stress in autogenous interpositional venous grafts by blood flow waveform analysis: clinical and experimental studies].

This investigation was designed to evaluate the postsurgical changes of autogenous, interpositional venous grafts in terms of the calculated wall shear stress by blood flow waveform analysis. In a model of tethered elastic tube, mean wall shear stress (tau) was obtained by the following equation: tau = 32 microQ/(pi.D3). Twenty-four grafts in repairing limb arterial injuries from 24 patients were examined with Doppler ultrasonic image instrument (7.5 MHz) for follow-up studies. Three mongrel dogs were selected for experimental studies. A segment of femoral vein (4-5 cm) was excised, reversed and interpositionally grafted into the femoral artery. The mean wall shear stress was calculated at 1 hour, 24 hours, 1 week, 4 and 12 weeks after implantation. Two occluded grafts were demonstrated in one femoral and one popliteal artery. The value of mean wall shear stress was higher in upper limb group (over 1.1 N/m2) than in lower limb group (five over 1.1 N/m2 and seven below 1.1 N/m2). The value of mean wall shear stress of grafts with follow-up time of more than 24 weeks was over 1.1 N/m2 in 6 grafts including one from lower limb while that was below 1.1 N/m2 in 6 grafts (all from lower limbs). No significant difference was found between the mean flow velocity values in upper and lower groups. The results from the experiment revealed that the value of mean wall shear stress decreased at one hour after operation, and increased and reached a fixed value beyond 1 week postsurgery. The vein graft in upper limb has better early and long-term result than that in lower limb because wall shear stress is correlated with the intimal hyperplasia, then the outcome of autogenous vein graft. In conclusion, we propose that wall shear stress be applied for follow-up studies on vascular grafts in limb arterial injuries and hemodynamic factors be considered for arterial reconstructive procedures.

Adolescent↗
PubMed1997

[Measuring EEG complexity for studying the state of mental load].

The complexity defined by Lemple and Ziv (1976) represents the degree of the sequence randomness. In this paper, the complexity of EEG under different mental loads was measured and the relation between the brain active state and the EEG complexity was analyzed. The results showed a statistically strong relation between the mental load and the EEG complexity. Further study showed that the heavier the mental load was the smaller the EEG complexity became. This correlation was especially apparent in the frontal lobe, and the complexity of EEG might be regarded as one of the parameters representing the functional state of the brain. The results indicate that EEG complexity represents the active state of brain in processing information, and the measurement of EEG complexity may provide a new path to the research in the advanced cognitive function of the human brain.

Adult↗
PubMed1997

[Expression of green fluorescent protein with baculovirus vector in insect cells].

The green fluorescent protein (GFP) gene was subcloned into the transfer vector pVLneo downstream of the polyhedrin gene (ocu) promoter. Insect cells were cotransfected with recombinant plasmid and Autographa californica Nuclear Polyhedrosis Virus (AcNPV) DNA. In the presence of G418, the recombinant virus containing GFP gene was purified. The GFP expressed in insect cells with a Mw of 30 kDa is observable by strong green light under a fluorescent microscope. Excitation and emission spectra of the GFP were 395 nm and 509 nm respectively. Integration of GFP gene on AcNPV genome was identified directly by Southern blot which gave strong hybridization signal between GFP cDNA probe and 1 kb EcoRI fragment of recombinant virus.

Animals↗
PubMed1997

[Screening of thermophilic superoxide dismatase producing strain and some properties of the enzyme].

A thermophilic SOD producing strain was obtained from the bacteria preserved in our lab. Its content of SOD was 8774u/g fresh cells. The strain can tolerate 0.4% H2O2 and 70 degrees C, and it has outstanding culture characteristics. It was identified as Bacillus stearothermophilus, called B.S 211-15. Crude SOD was extracted from B.S 211-15, the recovery of total activity was 69.5%, the specific activity was 1793u/mg protein. The enzyme showed fine heat stability, pH stability and good proteinase resistance. The SOD activity didn't decrease after being kept in room temperature for 2 months. The results of inhibition reactions indicated that this enzyme was Fe-SOD.

Geobacillus stearothermophilus↗
PubMed1997

[Using lyophilization to the preparation of drug paper disks for antimicrobial susceptibility test].

It was found that the paper disks used in the antimicrobial susceptibility test could be prepared by natural drying at 37 degrees C, but the drug distribution between these disks is not so enen as determined by antimicrobial inhibitory test, thus it was difficult to fit the needs of the national standards. Alternatively, we applied the lyophilization technique to the disks preparation and 12 batches, of different antibiotic disks were made out and found that the difference between disks is reduced, and all are meet to the national requirement. It is supposed that the capillary action may play a role in the variation of drug distribution in the natural drying process, and the lyophilization process avoided the capillary action, hence the more even distributed antibiotic disks are produced. The preparation of lyophilized disks is a simple and practical method that could be used in the antimicrobial susceptibility tests in hospital.

Freeze Drying↗
PubMed1997

[Studies on the changes of morphometry and neuropeptide of spinal neurons after peripheral nerve injury].

To observe the change of morphology and neuropeptide in the spinal neurons in order to clarify the functional state after injury of peripheral nerves is especially in the late stage. Sciatic nerves were cut with their proximal segments in the preparation of a model of peripheral nerve injury. Combination of horseradish peroxidase retrograde tracing immunohistochemistry and computer image analysis the changes in the morphometry of the perikarya of ventral horn neurons of the spinal cord, the quantitative changes of substance P (SP). Calcitonin gene-related peptide (CGRP) in dorsal horn and CGRP and choline acetyransferase (CHAT) in ventral horn of the spinal cord were examed. The results showd: (1) At the 3rd week after injury, swollen perikarya of the ventral horn neurons were observed, subseauently the swelling of perikarya was decreased tile the 6th week the neurons recovered to their normal size. At the 12th week the neurons were generally stable in their size, shortening of the dendrites was seen in 27% of the neurons. (2) The dendrites of the neurons progressively contracted till at the 12th week 53% of them were degenerated. The results of the 24th week were similar to the that at the 12th week. (3) CGRP in the ventral horn of the spinal cord was elevated to the highest point after 1 week of injury, that lasting for 4 weeks and 8 weeks later, the lever of CGRP returned to normal. From 20th to 24th week, there was no obvious changes of CHAT in the ventral horn of the spinal cord during observation. (4) SP went to the lowest point in the dorsal horn during 2-6 weeks, then recovered slowly, and beiny normal again after 16 weeks, however, CGRP was changed slightly. The results indicated that although a series of degenerating changes occurred in the neurons of the spinal cord during the late peripheral nerve injury, but the functional activity of the central meurons still was maintained at a certain level.

Animals↗
PubMed1997

[Peripheral nerve injury as a complication from orthopedic operation].

Nerve injury following operation is one of the main causes of the iatrogenic peripheral nerve injury. In order to learn lessons from these cases, one hundred and seven cases of peripheral nerve injury complicated with the orthopedic operations were analyzed. Forty-four cases were cutting injury during operation, made up 41% of all cases and 27 cases were stretch and compression injury, made up 25%. The involved nerves included 41 radial nerves and 24 common peroneal nerves, composing 60.7% of all nerve injury. The operations responsible were mainly the bone and joint operations, which made up 81%. The cause, prophylaxis, diagnosis and treatment were discussed. The rich appropriate knowledge of anatomy and responsibility of the surgeon were emphasized in order to prevent the occurrence of complication. Once the injury was suspected, diagnosis should be made promptly and effective treatment should be performed in time.

Adolescent↗
PubMed1997

[Pre- and post-operative changes in serum levels of glycocholic acid and 3,5,3'-triiodothyronine and their clinical significance in patients with cholelithiasis].

Pre- and post-operative changes of serum glycine-conjugated cholic acid (CG) and 3,5,3'-triiodothyronine (T3) levels were observed in twenty-two patients with cholelithiasis. The increase of the levels of serum CG varied with the patients; the highest levels were seen in patients with cirrhosis. After operation, the levels of serum CG and T3 were decreased significantly in patients without cirrhosis. There was positive correlation between serum CG and T3 (r = 0.4667, P < 0.01). It is indicated that the lowering of serum CG after operation may be related to the lowering of serum T3; the significant increase of serum CG level is useful to the diagnosis of liver cirrhosis, which is more sensitive than Type B ultrasonography or routine examination of liver function.

Adult↗
PubMed1996

Strain differences in adrenal CYP2D16 expression in guinea pigs. Relationship to xenobiotic metabolism.

Experiments were done to determine the mechanisms responsible for differences in adrenal microsomal xenobiotic metabolism between Strain 13 and English Short-Hair (ESH) guinea pigs. The rates of adrenal xenobiotic metabolism (bufuralol 1'-hydroxylase, benzo[a]pyrene hydroxylase, benzphetamine N-demethylase) were 2-3 times greater in microsomes from the Strain 13 animals. In both strains, xenobiotic-metabolizing activities were far greater in the inner zone (zona reticularis) than in the outer zones (zona fasciculata and zona glomerulosa) of the adrenal cortex. Northern blot analyses of total adrenal RNA with a CYP2D16 cDNA as the probe revealed significantly greater amounts of CYP2D16 mRNA in the Strain 13 guinea pigs. In addition, SDS-PAGE and Western blotting of adrenal microsomes demonstrated higher concentrations of CYP2D16 protein in Strain 13 than in ESH animals. Expression of CYP2D16 was predominantly in the inner zone of the adrenal, coinciding with the major site of xenobiotic metabolism. The results demonstrated higher levels of expression of CYP2D16 in adrenal glands from Strain 13 than from ESH guinea pigs, which may account for the strain differences in adrenal xenobiotic metabolism. Strain 13 guinea pigs should serve as a good experimental model for further studies on the regulation of adrenal CYP2D16.

Adrenal Glands↗
PubMed1996

Proteolytic activation of protein kinase C delta by an ICE/CED 3-like protease induces characteristics of apoptosis.

Recent studies have shown that protein kinase C (PKC) delta is proteolytically activated at the onset of apoptosis induced by DNA-damaging agents, tumor necrosis factor, and anti-Fas antibody. However, the relationship of PKC delta cleavage to induction of apoptosis is unknown. The present studies demonstrate that full-length PKC delta is cleaved at DMQD330N to a catalytically active fragment by the cysteine protease CPP32. The results also demonstrate that overexpression of the catalytic kinase fragment in cells is associated with chromatin condensation, nuclear fragmentation, induction of sub-G1 phase DNA and lethality. By contrast, overexpression of full-length PKC delta or a kinase inactive PKC delta fragment had no detectable effect. The findings suggest that proteolytic activation of PKC delta by a CPP32-like protease contributes to phenotypic changes associated with apoptosis.

Amino Acid Sequence↗