PubMed Health⌕ Search

Biomedical subjects

W D Zhang

Publications and source records attributed to W D Zhang.

At least 55 records · Page 3Linked to original sources
PubMed1993

Immunohistochemical localization of paraquat in skin and eye of rat.

Immunohistochemical techniques were used to observe the localization of paraquat in the skin and eyes of rats. Paraquat poisoned rats were killed 3 h, 12 h, 24 h, 3 days, 7 days and 10 days after intravenous administration of paraquat. In skin, paraquat was localized in the ducts of sweat glands and sebaceous glands between 3 and 10 days after paraquat injection. In eyes, weak positive findings were observed in nerve fibers of retina between 3 and 10 days after the injection. In cornea, paraquat was localized in epithelial cells at the first 3 h and between 3 and 10 days after paraquat administration. Since skin occupies a vast area of the body in animals, as an organ, it seems to be an important storage pool for the redistribution of paraquat.

Animals↗
PubMed1993

[A case report of acute death caused by hyperextension injury of neck].

We report an autopsy case of acute death from an upper cervical spinal cord injury caused by hyperextension of the neck. A 59-year-old drunken man who had been suffering from cervical spondylosis was slapped in the face, fell flat on his face, and remained as such for 4 hours. The victim was carried to a hospital, he had already been dead on arrival. Although he received an intensive care, he remained unconscious for 12 hours until a cardiac arrest. The findings of an autopsy were as follows: Externally, excoriation on the forehead and the left eyebrow and slight subcutaneous hemorrhage in the dorsum of the nose were observed. The intervertebral disk and the anterior longitudinal ligament between the 5th and 6th cervical vertebrae were severed, and a lot of bleeding in the region of the injuries was observed. The 6th cervical spinous process was fractured in the direction to a major axis. A part of the posterior root filaments was torned and the bleeding points could be seen on the front of the 6th cervical spinal cord. In the cross section of the 6th cervical spinal cord, the typical hemorrhagic necrosis could be recognized surrounding the central canal, whereas the similar finding was observed at the second cervical spinal cord. On the histopathological examinations, in C2, C5-C6 regions marked ischemic changes and hemorrhagic necrosis could be observed. From these post-mortem results, we diagnosed that the victim died from an upper spinal cord damage due to a stretching consequence of the hyperextentional injury.

Autopsy↗
PubMed1992

Immunohistochemical classification of astrocytes in infants by glial fibrillary acidic protein staining and application to forensic practice.

This study was designed to assess whether development of the astrocytes in central nervous system (CNS) is delayed in victims of the sudden infant death syndrome (SIDS), and to try the classification of astrocytes by a morphological method. The glial fibrillary acidic protein (GFAP) is the major component of astrocytic fiber and is characteristic of astrocytes in the human CNS. An immunohistochemical study identificating this protein was carried out on infant brains to evaluate astrocytes. Morphologically 39 brains of infants aging under 12 months old, that including 10 asphyxia, 13 respiratory infections and 16 SIDS cases, were stained for GFAP by the peroxidase-anti-peroxidase (PAP) method. According to their staining pattern astrocytes were classified into 4 cell types: Type I cells were seen during the non-proliferating period, Type II cells during the low-proliferating period, Type III cells during the moderate-proliferating period and Type IV cells during the high-proliferating period. On the basis of this classification of astrocytes, it was observed that the first and most reactive pattern of physiological proliferation was in infant brains four months old after birth in the asphyxia cases. The staining grade of astrocytes was significantly less in white matter in the SIDS victims compared with age-matched of the respiratory infections and asphyxia. Therefore, we suggest that development of brain in the SIDS cases is delayed to controls and that the SIDS is associated with a developmental CNS disorder. Among 3 group cases the retarded staining pattern of the astrocytes in SIDS is interesting and might give a helpful approach to diagnosis of the cause of death for SIDS.

Astrocytes↗
PubMed1991

Replantation of severed fingers: two unique cases.

Two cases of amputated digits are reported. One involved a period of ischemia at freezing temperatures, and the other at unusually high temperatures. Both fingers survived upon replantation. The implications of extreme temperature upon ischemic tissues are discussed.

Adult↗
PubMed1991

Detection and identification of human influenza viruses by the polymerase chain reaction.

A series of oligonucleotide primers are described which hybridize to conserved regions of influenza virus cDNA and prime DNA synthesis in Taq polymerase catalyzed amplification reactions (PCR). Primers were designed to hybridize as nested pairs and, following a two-step amplification, produce uniquely sized DNA fragments diagnostic for viral type and subtype. Influenza A and B matrix-protein genes and the influenza C haemagglutinin gene were targets for the type-specific primers. Subtype-specific primers targeted conserved sequences within the three haemagglutinin or two neuraminidase subtypes of different human influenza isolates. The utility of this method was demonstrated using computer search methods and by accurately amplifying DNA from a variety of influenza A, B, and C strains. Type-specific primer sets showed a broad type specificity and amplified DNA from viral strains of unknown sequence. Restriction mapping and DNA sequencing showed that fragments amplified in this manner derived from the input template, confirming the accuracy of the method and demonstrating how PCR can be used to quickly derive sufficient sequence information for analysis of viral relatedness. Subtyping primers were able to distinguish accurately between the three haemagglutinin (H1, H2, H3) and two neuraminidase (N1, N2) alleles of human influenza A isolates. Again DNA was amplified from viruses of unknown sequence confirming that most of these primer sets may prove useful as broad range subtyping reagents. In order to simplify the work associated with analysis of many samples, we have also devised a rapid method for the isolation of viral RNA and synthesis of cDNA. Using this 'mini-prep' technique, it is possible to detect, amplify, and identify picogram quantities of influenza virus in a single day, confirming that PCR provides a useful alternative to existing methods of influenza detection.

Animals↗
PubMed1990

Allele loss on chromosome 16 associated with progression of human hepatocellular carcinoma.

Loss of heterozygosity on chromosome 16 is a common genetic alteration in human hepatocellular carcinoma (HCC). To clarify the pathogenetic significance of allele loss on chromosome 16, we performed restriction fragment length polymorphism analysis of 70 surgically resected tumors by using 15 polymorphic DNA markers for chromosome 16. Loss of heterozygosity on chromosome 16 was detected in 36 (52%) of 69 informative cases, and the common region of allele loss in these 36 tumors was located between the HP locus (16q22.1) and the CTRB locus (16q22.3-q23.2). These losses occurred more frequently in HCCs of poor differentiation, of larger size, and with metastasis, whereas they were not detected in HCC at the earliest stage. In addition, these losses were not associated with presence or absence of hepatitis B virus DNA integration or hepatitis C virus infection. These results show that loss of heterozygosity on chromosome 16 is a late event occurring after hepatocarcinogenesis and strongly suggest that this phenomenon is involved in enhancement of tumor aggressiveness during progression of HCC.

Alleles↗
PubMed1990

Frequent loss of heterozygosity on chromosomes 16 and 4 in human hepatocellular carcinoma.

By restriction fragment length polymorphism analysis, we examined loss of heterozygosity at 34 loci on 23 chromosomes in 35 surgically resected human hepatocellular carcinomas. Allele losses at the HP locus on chromosome 16q22 and at the MT2P1 locus on chromosome 4p11-q21 were detected in 57% (8/14) and 50% (8/16) of cases, respectively. Loss of heterozygosity on chromosomes 16q and 4 occurred simultaneously in 4 of 7 informative cases for both loci, and seemed to be important in the development of human hepatocellular carcinoma irrespective of the presence of hepatitis B virus infection. In contrast, the incidence of allele loss was low at the other loci, e.g., chromosome 1p, 3p, 11p, 13q or 17p, where one allele is frequently lost in other cancers.

Carcinoma, Hepatocellular↗
PubMed1990

A study of the pesticide fenthion: toxicity, mutagenicity, and influence on tissue enzymes.

In this paper results of acute toxicity (oral and dermal), cumulative toxicity, subchronic toxicity, and conjunctiva irritation tests are reported. The mutagenic effects of fenthion, using SCE (in vivo) and UDS (in vitro) as indicators, were also tested. Histochemical changes in enzyme activities (including AChE, ATPase, and AKP) in tissues were observed. The results showed that the acute toxicity of fenthion belongs to highly toxic category. The highly cumulative effect of fenthion was also observed. The subchronic toxicity test, however, did not reveal any abnormal effects except the inhibition of ChE activity in plasma. The dose and ChE activity relationship equation was Y = 0.82x + 4.71. The SCE and UDS tests revealed no mutagenic potential. In histochemical experiments we found that AChE activity in tissues was markedly inhibited. AKP and ATPase activities at the cortex renis were increased in the treated rats.

Acetylcholinesterase↗
PubMed1987

The study of byssinosis in China: a comprehensive report.

Cross-sectional studies were conducted during 1981-1983 among 861 textile workers in 3 cotton mills and 822 controls in 2 silk factories. Questionnaire and lung function tests were taken and inhalable dust concentrations were measured. Prevalence of byssinosis was 5.6%. Average dust concentrations were highest in carding rooms, 1.47-1.99 mg/m3. The correlations (r) between prevalence of byssinosis and dust concentrations was 0.64 (p less than 0.05). The prevalence of chronic bronchitis was 14.4% in cotton workers and 5.1% in controls (p less than 0.05). Acute FEV1 percent decrement (greater than 5%) was higher among cotton workers (32.1%) compared to controls (14.5%) (p less than 0.001). In one cotton blanket factory, the prevalence of byssinosis and chronic bronchitis was higher among workers in the high-dust work areas. Long-term effect studies included pulmonary function test among 173 cotton workers and 373 controls, retired 1-10 years, using the flow volume curve (FVC); chest X-rays of 140 pairs of cotton workers and controls with working tenures over 20 years; and examination of lobectomy specimens of 8 textile workers matched with 16 controls. In male cotton workers, only smokers had a prominent decrement of lung function indices, except FVC. For non-smoking females, there was no difference between the two groups. Additive effects were seen between smoking and dust exposure. According to the International Labor Organization (ILO) Pneumoconiosis Classification, the prevalence of abnormality (profusion greater than 1/0) was 4.3% and 8.7% in non-smoking controls and cotton workers. The interstitial changes on X-ray due to smoking would be much heavier. Additive effects also existed between smoking and dust exposures. No significant changes attributable to dust exposure were seen on pathological section of lobectomy specimens.

Aged↗
PubMed1986

Radiographic findings in cotton textile workers and the relationship to cigarette smoking.

A group of 140 cotton textile workers from Shanghai, Shandong, Guangxi, and Beijing have had their chest radiographs taken using similar requirements. Most had come from the preparatory departments of cotton mills and had a history of exposure to cotton dust for at least 20 years. As controls, 140 healthy individuals with no dust exposure were matched with respect to sex, age, and smoking history. All the radiographs were read according to the ILO International Pneumoconiosis Classification, and the manifestations belonging to categories 0/0 and 0/1 were grouped as "normal," whereas categories 1/0, 1/1, and 1/2 and above as "abnormal." There was no significant difference in X-ray abnormalities between cotton textile workers and controls (P greater than 0.05). But when the data on the cotton textile workers and controls were combined, an appreciable difference in the incidence of radiographic abnormalities was found between smokers and non-smokers (P less than 0.001). Cotton dust exposure may induce nonspecific interstitial pulmonary changes, but these changes were exaggerated by cigarette smoking. These two factors appeared to have an additive effect on the pulmonary X-ray findings.

Female↗