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Biomedical subjects

C Wang

Publications and source records attributed to C Wang.

At least 1,171 records · Page 65Linked to original sources
PubMed1991

Effects of cranial irradiation on hypothalamic-pituitary function--a 5-year longitudinal study in patients with nasopharyngeal carcinoma.

The effects of cranial irradiation on hypothalamic-pituitary function were studied over a 5-year period in 31 adult patients with nasopharyngeal carcinoma. The estimated radiotherapy doses to the hypothalamus and pituitary were 3979 +/- 78 (+/- SD) and 6167 +/- 122 cGy, respectively. Within 2 years of radiotherapy, significant impairment in the secretion of growth hormone, gonadotrophins, corticotrophin and thyrotrophin were evident and 14 per cent of patients developed hyperprolactinaemia. Using life table analysis, the cumulative probability of endocrine dysfunction was estimated to be 62 per cent after 5 years with deficiencies in growth hormone, gonadotrophins, corticotrophin and thyrotrophin found in 63.5, 30.7, 26.7 and 14.9 per cent of patients, respectively. Growth hormone deficiency was the earliest endocrine dysfunction observed. Hyperprolactinaemia was uncommon in the male patients but occurred in five of eight women within 3 years of cranial irradiation. The alterations in gonadotrophin secretion suggest a defect in the pulsatile release of gonadotrophin releasing hormone. Twenty-eight patients developed a hypothalamic pattern of delayed thyrotrophin response to thyrotrophin releasing hormone one year after radiotherapy--four subsequently became hypothyroid. Patients who received radiotherapy for cervical lymph nodes were at greater risk of developing hypothyroidism. Thus, in these patients with no pre-existing disease in the hypothalamic-pituitary region, progressive impairment in hypothalamic pituitary function leading to endocrine dysfunction requiring treatment occurs in 50 per cent of patients 5 years after cranial irradiation. Regular endocrine assessment should be performed in all patients following cranial irradiation.

Adrenocorticotropic Hormone↗
PubMed1991

Four-year experience in the treatment of upper gastrointestinal strictures with balloon dilatation.

One hundred and sixty-four cases of upper gastrointestinal tract stricture were treated by balloon dilatation in 4 years. A total of 682 procedures were performed. One hundred and forty cases (anastomosis stenosis 95, caustic stenosis 33 and other stenoses of the esophagus 12) were followed up with an effective rate of 90% (126/140) and a long-term effective rate of 71.4% (100/140). Fourteen cases (10%) failed, and 11 of them were due to tumor recurrence. The concept about the short-term and long-term effects, the criteria for evaluation of the results, the factors influencing the effectiveness, and the time suitable for dilatation are described. For the dilatation, indications are anastomosis stricture of the upper gastrointestinal tract, esophageal web and caustic stenosis of the esophagus. This method is also indicated for cicatricial stricture of the upper gastrointestinal tract of various causes.

Adolescent↗
PubMed1991

[Investigation of C4 haplotypes in Han nationality of Hubei Province in China].

C4 haplotypes of 93 unrelated families of Han nationality in Hubei Province were determined by means of a method established in our laboratory based on the techniques recommended in the 4th International Workshop for the Genetics of Complement and the method of Carboxypeptidase B developed by Zhang in Australia. 310 C4 haplotypes were analysed. The haplotype frequency of A3B1 (0.4194) was found to be the highest in Han nationality of Hubei in China. The others are as follows: A3B2: 0.1161, A2B1 and A4B2: both 0.0903, AQOB1: 0.0645, A3BQO: 0.0548, AQOBQO: 0.0322, A2B2: 0.0256, A4B1: 0.0161, A2B92: 0.0129. Some kinds of rare haplotypes were also discovered. Significant positive-linkage disequilibrium parameters (delta) were found in haplotypes of A4B2, AQOBQO and A2B92, while the significant negative delta was observed in that of A4B1 and AQOB2. Our data were compared with those of Japanese, Caucasian in USA and Germany, Negroids in South Africa are discussed in the paper. The differences among them.

Asian People↗
PubMed1991

C4A deficiency and poor prognosis in patients with IgA nephropathy.

IgA nephropathy (Berger's disease) is an important cause of end-stage renal failure in persons of Asian and European descent. We performed C4 phenotyping on plasma from 123 patients with IgA nephropathy who resided in several different parts of the United States. All of these patients underwent diagnostic renal biopsy in adulthood. Six patients had a total deficiency for the C4A protein and all six had chronic renal insufficiency (serum creatinine concentration higher than 1.4 mg/dl at last follow-up). In contrast, 47% of the patients without C4A deficiency had chronic renal insufficiency (p = 0.001). The C4 gene defect was due to deletion of both C4A genes in only two individuals, whereas three patients were heterozygous for the C4A gene deletion. We speculate that the functional alteration of the complement system related to C4A deficiency might lead to expression of clinically severe disease in an individual with a genetic susceptibility to IgA nephropathy.

Chromosome Deletion↗
PubMed1991

[Research on the relationship between central acetylcholine and acupuncture analgesia].

The article systematically reported our physiological and biochemical work on the relationship between central acetylcholine and acupuncture analgesia. The results indicate: 1. Acupuncture on acupoints could produce analgesia. 2. Ach contents in cerebrospinal fluids and brain increased under acupuncture analgesia. 3. AChE activities iu brain elevated under acupuncture analgesia. 4. ChE inhibitor reinforced the effects of acupuncture and inhibitor of ACh synthesis could inhibit the effects of acupuncture, which could be reversed by administration of ACh and chlorocholine. M-AChR antagonists could also inhibit the effects of acupuncture. 5. The turnover rate of ACh in diencephalon, caudate nucleus and spinal dorsal horn accelerated when acupuncture analgesia. The discussion was given on the variation of metabolic dynamics in combination with related literature.

Acetylcholine↗
PubMed1991

[Differentiation of the sex of Trichinella larvae collected in Changchun].

The length of the rectum in male Trichinella spiralis larvae is about twice that in female larvae, being 54.39 (50.4-63.0) microns in males and 28.05 (18.9-31.35) microns in females. The gonad rudiment of the female larvae has already differentiated obviously into seminal receptacle rudiment and uterus rudiment, while that of the male larvae remains undifferentiated. The seminal receptacle rudiment is a granular, small mass and dark brown in color, while the uterus rudiment is composed of a column of several cells, and the total length of these two rudiments is 62.18 (50.4-75.6) microns. Verifications through experimental infections proved that the length of rectum and the degree of differentiation of gonad rudiment might be used as indices to identify the sex of larvae. It was found that the sexual ratio of T. spiralis collected in Changchun was 1.82:1 (1.17-2.59:1).

Animals↗
PubMed1991

Computer-assisted assessment of human sperm morphology: comparison with visual assessment.

OBJECTIVE: Sperm morphology classification was analyzed by the computer-assisted semen analysis equipped with the Morphologizer II (Cryo Resources Ltd., New York, NY) was compared with the traditional manual method. DESIGN, SETTING, PATIENTS: Fifty stained semen smears from men attending the infertility clinic of a tertiary referral institution were studied. MAIN OUTCOME MEASURES: Sperm head morphology was classified by the two methods into the following forms: normal, small oval, big oval, taper, and amorphous. RESULTS: Overall, the classifications of mean percent normal, small, and amorphous head forms were similar in the two methods. However, the differences between paired values obtained by the two methods were highly variable (range from -20% to +20%). The large differences between the methods were related to the large coefficients of variations present when classifying abnormal sperm morphology even by the same experienced technician. Only the percent normal spermatozoa could be classified by both methods with acceptable precision. In contrast, the variations in the morphometric analyses between the different semen smears were very small. CONCLUSIONS: There was no advantage of the morphologizer over the manual method in sperm morphology classification. The clinical value of morphometric parameters of spermatozoa has to be defined.

Humans↗
PubMed1990

Determining local conformational variations in DNA. Nuclear magnetic resonance structures of the DNA duplexes d(CGCCTAATCG) and d(CGTCACGCGC) generated using back-calculation of the nuclear Overhauser effect spectra, a distance geometry algorithm and constrained molecular dynamics.

Two-dimensional nuclear magnetic resonance (n.m.r.) spectroscopy and a variety of computational techniques have been used to generate three-dimensional structures of the two DNA duplexes d(CGCCTAATCG) and d(CGTCACGCGC). The central six base-pairs in these two decamers contain all ten dinucleotide pairs in DNA and thus, represent a model system for investigating how the local structure of DNA varies with base sequence. Resonance assignments were made for the non-exchangeable base protons and most of the C-1'-C-4' sugar protons in both decamers. Three-dimensional structures were generated using a distance geometry algorithm and these initial structures were refined by optimizing the fit of back-calculated spectra against the experimental two-dimensional nuclear Overhauser effect (NOE) spectra. This back-calculation procedure consists of calculating NOE cross relaxation rates for a given structure by solution of the Bloch equations, and directly accounts for spin diffusion effects. Use of this refinement procedure eliminates some assumptions that have been invoked when generating structures of DNA oligomers from n.m.r. data. Constrained energy minimization and constrained quenched molecular dynamics calculation were also performed on both decamers to help generate energetically favorable structures consistent with the experimental data. Analysis of the local conformational parameters of helical twist, helical rise, propeller twist, displacement and the alpha, beta, gamma, epison and zeta backbone torsion angles in these structures shows that these parameters span a large range of values relative to the X-ray data of nucleic acids. However, the glycosidic and pseudorotation angles are quite well defined in these structures. The implications that these results have for determination of local structural variations of DNA in solution, such as those predicted by Callidine's rules, are discussed. Our results differ significantly from some previous studies on determining local conformations of nucleic acids and comparisons with these studies are made.

Algorithms↗
PubMed1990

Addisonian crisis as presenting feature in malignancies.

Metastases to the adrenal glands are common in patients with malignancy but malignant disease presenting as Addisonian crisis is rare. The authors presented two patients with acute Addisonian crises due to metastatic infiltration of the adrenal glands. They were otherwise asymptomatic from the primary tumor. Computed tomographic scan showed bilateral adrenal enlargement and transcutaneous biopsy confirmed metastatic adenocarcinoma in the adrenals. Adequate glucocorticoid replacement improves quality of life and prolongs survival.

Acute Disease↗