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Biomedical subjects

T Zhao

Publications and source records attributed to T Zhao.

At least 91 records · Page 5Linked to original sources
PubMed1997

Tetrandrine potently inhibits herpes simplex virus type-1-induced keratitis in BALB/c mice.

This study investigated the effect of tetrandrine (TDR) on experimental herpes simplex keratitis (HSK) in mice. BALB/c mice were divided as follows: Group 1, untreated; Group 2, acyclovir (ACV)-treated from day 0 postinfection; Group 3, ACV-treated from day 7; Group 4, TDR-treated from day 0; and Group 5, TDR-treated from day 7. All mice were infected in the right cornea with herpes simplex virus (HSV) type I. TDR 30 mg/kg and ACV 120 mg/kg were administered intraperitoneally daily. The mice were observed for 14 days postinfection. Clinical inflammatory reactions and ocular histopathology were analyzed. The herpes specific antibody response and the delayed type hypersensitivity (DTH) response were studied. Of the 22 untreated mice, 16 developed HSK (incidence, 72.7%). TDR given from day 7 reduced the HSK incidence to 8.5% (p < 0.01); the incidence of HSK was 45.4% in mice treated with TDR from day 0 (p > 0.05). Systemic ACV given from day 0 inhibited HSK development (p < 0.01); ACV given from day 7 resulted in an HSK incidence of 50% (p > 0.05). The specific anti-HSV antibody response in the serum of mice treated with TDR or ACV either from day 0 or day 7 was significantly less than that of untreated mice (p < 0.01 and p < 0.05, respectively), and TDR treatment suppressed DTH responses to HSV (p < 0.05). Systemic TDR administered after HSV inoculation of the cornea significantly modulates murine HSK development at least partly by modifying the host immune/inflammatory response to the virus.

Alkaloids↗
PubMed1997

[Hepaticocholangiochole cystostomy plus construction of subcutaneous tunnel of the gallbladder in the treatment of hepatolithiasis with bile duct stricture].

A novel operation was designed by using Hartmann's pouch of the gallbladder to anastomose stone-strictured intrahepatic bile duct while leaving the common bile duct and Oddis sphincter intact and fixing the fundus of the bladder subcutaneously. 28 patients with intrahepatic bile duct stones and strictures underwent the operation successfully, and recovered well. There were no postoperative complications such as reflux cholangitis or disturbances of GI tract.

Adolescent↗
PubMed1996

Fate of enterohemorrhagic Escherichia coli O157:H7 in bovine feces.

Dairy cattle have been identified as a principal reservoir of Escherichia coli O157:H7. The fate of this pathogen in bovine feces at 5, 22, and 37 degrees C was determined. Two levels of inocula (10(3) and 10(5) CFU/g) of a mixture of five nalidixic acid-resistant E. coli O157:H7 strains were used. E. coli O157:H7 survived at 37 degrees C for 42 and 49 days with low and high inocula, respectively, and at 22 degrees C for 49 and 56 days with low and high inocula, respectively. Fecal samples at both temperatures had low moisture contents (about 10%) and water activities ( < 0.5) near the end of the study. E. coli O157:H7 at 5 degrees C survived for 63 to 70 days, with the moisture content (74%) of feces remaining high through the study. Chromosomal DNA fingerprinting of E. coli O157:H7 isolates surviving near the completion of the study revealed that the human isolate strain 932 was the only surviving strain at 22 or 37 degrees C. All five strains were isolated near the end of incubation from feces held at 5 degrees C. Isolates at each temperature were still capable of producing both verotoxin 1 and verotoxin 2. Results indicate that E. coli O157:H7 can survive in feces for a long period of time and retain its ability to produce verotoxins. Hence, bovine feces are a potential vehicle for transmitting E. coli O157:H7 to cattle, food, and the environment. Appropriate handling of bovine feces is important to control the spread of this pathogen.

Animals↗
PubMed1996

[Loss of alveolar attachments in smoker's lungs and its relation to small airway abnormalities].

The alveolar attachments and small airway abnormalities in the lungs of smokers were measured by computerized imaging to study the relationship between loss of alveolar attachments and small airway abnormalities, the smoker's lungs were divided into three groups: no emphysema (NE), centrilobular emphysema (CLE) and panlobular emphysema (PLE). The distance between normal alveolar attachments (Distance) and percent abnormal alveolar attachments (% Abnormal) in CLE were significantly higher than in NE (P < 0.05 and P < 0.01), and no significant difference in the number of normal alveolar attachments in the 3 groups. The small airway wall area (WA) and deformity index (DI) in CLE differed significantly from MA and DI in NE (P < 0.05 for all). There were no differences between PLE and NE in these indices. Distance and % Abnormal correlated significantly with WA and DI, but the correlations were shown only in CLE. We concluded that alveolar attachment destruction in smoker's lungs was closely associated with small airway abnormalities, which indicated the different patterns of emphysema, CLE and PLE, probably have different pathogenesis respectively.

Adult↗
PubMed1996

[A study on the control of air toxic chemicals in workplace for bakelite manufacturing and casting].

Air concentrations of phenol, formaldehyde and ammonia related to the contents of free phenol, formaldehyde in raw material, and solidifying agent-urotropine in bakelite. Due to the solubility of phenol and formaldehyde, in the manufacture process, water was added to lower contents of phenol and formaldehyde in bakelite, and content of urotropine was reduced in bakelite sand presceription to lower air concentrations of phenol, formaldehyde and ammonia. As contents of phenol and formaldehyde in bakelite reduced to 4.9% and 0.037% from 6.32% and 0.062%, respectively, air concentrations of phenol, formaldehyde and ammonia lowered to 0.61 mg/m3, 0.69 mg/m3, and 5.1 mg/m3 from 2.94 mg/m3, 1.72 mg/m3, and 12.9 mg/m3, respectively, and incidence rate of skin disease in the employees of the workplace decreased to zero from 80.2%. It is recommended that a hygienic standard for allowable concentration of mixed toxic chemicals in the workplace air for bakelite manufacturing be formulated as soon as possible.

Air Pollutants, Occupational↗
PubMed1996

[On diagnostics of malignant meningioma and invasive meningioma].

We have made a clinicopathological study of 90 cases of malignant meningiomas and 18 cases of invasive meningiomas. The results show that the diagnostic features of malignant meningioma include increased cellularity, nuclear pleomorphism, tumorous giant cells, numerous mitotic figures, focal necrosis, cystic change and hemorrhage. The diagnosis of malignant meningioma can be more positively made when invasive growth, recurrence and metastasis are present. In making the diagnosis of invasive meningioma, both changes of benign meningioma and invasive growth should be present.

Adolescent↗
PubMed1995

Enthalpy and entropy of hydration of bovine crystallins.

Transparency of the lens of the eye is the result of a short range order in the packing of crystallin molecules within the fiber cells. Short range order depends on crystallin-crystallin as well as water-crystallin interactions. Light scattering measurements can provide information on the hydration of crystallins. Light scattering intensities were obtained as a function of scattering angle, concentration, and temperature on dilute solutions of beta H, beta L, and gamma fractions of bovine lens crystallins. The temperature dependence of the second virial coefficient was negative for the beta crystallin fractions and positive for the gamma fraction as well as that for alpha crystallin (Wang, X., and Bettelheim, F. A. (1989) Proteins Struct. Funct. Genet. 5, 166-169). The partial molar enthalpy values of the solutions were negative for the beta crystallin fractions, indicating a tendency for homo- and heterodimer and -oligomer association. The enthalpy values were positive for the alpha and gamma fractions. The negative values of the enthalpy of solutions differentiate the beta crystallins from the other crystallins. The partial molar entropy values of solutions of beta L and gamma fractions were identical, those of the oligomeric beta H fraction were higher, whereas those of alpha crystallin were a magnitude larger than those of the smaller crystallin molecules.

Animals↗
PubMed1995

Risk factors for fecal shedding of Escherichia coli O157:H7 in dairy calves.

A case-control study was conducted to determine risk factors for fecal shedding of Escherichia coli O157:H7 (ECO) in dairy calves. Three herds previously found to lack calves that shed ECO in their feces were selected for each herd previously found to have calves that shed ECO. Fecal samples from 965 calves on 64 farms were tested for ECO by microbial culture. Sample prevalence of ECO in calves less than 8 weeks old was 1.4% and in calves 8 weeks or older was 4.8%. Calves were 3 times more likely to shed ECO after weaning than before weaning. Shedding of ECO was associated with grouping calves before weaning; feeding whole cottonseed was negatively associated with ECO shedding. The change in results between testing periods illustrated that an individual herd's status cannot be defined by a single testing of a small sample of cattle.

Age Factors↗
PubMed1995

Molecular characterisation of Escherichia coli O157:H7 isolates by pulsed-field gel electrophoresis and plasmid DNA analysis.

Foods of bovine origin have been identified as sources of Escherichia coli O157:H7. Genomic DNA of E. coli O157:H7 isolates from patients (six isolates), food samples (18 isolates from ground beef and six isolates from raw milk) and calf faecal samples (31 isolates) were characterised by pulsed-field gel electrophoresis (PFGE) and plasmid DNA analysis. These isolates originated from different locations in the USA during 1992 and 1993. Twenty-one distinct genomic profiles were generated from the 61 isolates by PFGE after digestion with the endonuclease XbaI. Four genomic profiles were identified among five patient isolates and the remaining patient isolate was not typable. Five different profiles were detected amongst the isolates from ground beef, one of which was associated with 13 ground beef isolates from an outbreak in the Pacific Northwest of the USA in 1993. The PFGE profile of five calf isolates from Washington and Wisconsin was identical to the profile of the ground beef isolates from the outbreak, suggesting that these isolates were related. Similarly, one PFGE profile accounted for three isolates from calf faeces and one from ground beef. Six raw milk isolates from Georgia were indistinguishable both from each other and from one isolate from calf faeces. Fourteen genomic profiles were identified among 31 calf faecal isolates from 18 different herds in 11 states. Only five plasmid profiles were identified among the 61 isolates. PFGE was shown to be a useful typing technique for E. coli O157:H7.

Animals↗
PubMed1995

Prevalence of enterohemorrhagic Escherichia coli O157:H7 in a survey of dairy herds.

The prevalence of Escherichia coli O157:H7 in dairy herds is poorly understood, even though young dairy animals have been reported to be a host. From February to May 1993, 662 fecal samples from 50 control herds in 14 states, and from June to August 1993, 303 fecal samples from 14 case herds in 11 states were collected for isolation of E. coli O157:H7. Case herds were those in which E. coli O157:H7 was isolated from preweaned calves in a previous U.S. Department of Agriculture study, whereas control herds from which E. coli O157:H7 had not been isolated previously were randomly selected from the same states as case herds. Among the control herds, E. coli O157:H7 was isolated from 6 of 399 calves (1.5%) that were between 24 h old and the age of weaning and from 13 of 263 calves (4.9%) that were between the ages of weaning and 4 months. Eleven of 50 control herds (22%) were positive. Among the case herds, E. coli O157:H7 was isolated from 5 of 171 calves (2.9%) that were between 24 h old and the age of weaning and from 7 of 132 calves (5.3%) that were between the ages of weaning and 4 months. Seven of 14 case herds (50%) were positive. Sixteen of 31 isolates were obtained by direct plating, with populations ranging from 10(3) to 10(5) CFU/g. Fifteen of 31 isolates were isolated by enrichment only. Nineteen of the isolates produced both verocytotoxin 1 (VT-1) and VT-2, whereas 12 produced VT-2 only.

Animal Husbandry↗
PubMed1994

Purity control of different bee venom melittin preparations by capillary zone electrophoresis.

A rapid capillary zone electrophoresis method was developed for the determination of melittin during its purification from bee venom by column chromatography. Low-pH buffer was selected to decrease the adsorption of the analytes on capillary wall. The average relative standard deviations of the migration time of melittin and of the peak area were 1.2 and 2.3%, respectively.

Bee Venoms↗
PubMed1994

Growth and verotoxin 1 production by Escherichia coli O157:H7 in ground roasted beef.

Production of verotoxin 1 (VT1) by hemorrhagic Escherichia coli O157:H7 in food has received limited research attention. A study was therefore conducted to determine the effect of temperature and pH, as achieved using two different acidulants, on VT1 production in ground roasted beef slurry. Slurries (pH 5.9) containing 33% beef and 67% water were incubated at 21 degrees C or 37 degrees C. Transfers were made at 48-h intervals for up to 18 days to determine if repeated subculturing influenced VT1 production. Populations of E. coli O157:H7 ranged from 8.9 x 10(8) to 1.9 x 10(9) CFU/ml within 48 h of transfer, regardless of incubation temperature. Maximum VT1 concentrations ranged from 61 to 63 ng/ml and 63 to 85 ng/ml of slurries incubated at 21 degrees C and 37 degrees C, respectively. The amount produced within 48 h at 37 degrees C was 15-24% higher than the amount produced at 21 degrees C and did not change after ten successive 48-h transfers. Upon changing the incubation temperature of slurry cultures adapted to 21 degrees C to an incubation temperature of 37 degrees C, VT1 production increased within 48 h to the level of cultures which had been previously adapted to 37 degrees C. A shift in temperature from 37 degrees C to 21 degrees C resulted in an initial reduction of about 55% in the amount of VT1 produced within 48 h. For studies on the combined effect of incubation temperature, pH and acidulant, slurries were adjusted to pH 5.4 with acetic and citric acids. Growth and production of VT1 in slurry acidified with acetic acid was markedly reduced compared to that in the control slurry (pH 5.9). The amount of VT1 detected in slurries receiving the second and third 24-h transfer of culture incubated at 21 degrees C was essentially nil. Growth and VT1 production was reduced in slurry acidified with citric acid compared to that observed in the control slurry but not as drastically as that observed in slurry acidified with acetic acid. VT1 concentration in unacidified beef slurry (pH 5.9) and in beef slurry acidified at pH 5.4 with citric acid reached 21 and 16 ng/ml, respectively, within 24 h at 21 degrees C. Results emphasize the need for proper sanitation procedures in beef processing and preparation facilities to reduce the risk of cross contamination of roasted beef and subsequent growth of E. coli O157:H7 and VT1 production.

Animals↗
PubMed1994

[The application of PCR technique in genetic diagnosis of non-Hodgkin's lymphoma].

In this study, specimens from 59 cases of non-Hodgkin's lymphoma (NHL) were immunophenotyped with L26 and UCHL-I McAb, then investigated for gene rearrangement by PCR technique. The results showed that the rates of positive amplification of clonal IgH and TCR beta gene rearrangement were 71.4% (10/14) and 83.3% (10/12) respectively in the fresh tissues, and the IgH (semi-nested PCR technique) and TCR beta were 80% (12/15) and 73.3% (11/15) respectively in paraffin embedded tissues. Definitive diagnosis was made for the 6 cases which could not be diagnosed by routine and immunohistochemical methods, and all 6 exhibited IgH or TCR beta single band. No cases with pseudopositive amplification were discovered. This study suggested that the PCR technique was the most specific, sensitive and rapid detection method for clonal gene rearrangement in NHL.

DNA, Neoplasm↗
PubMed1994

[Experimental study on anti-senility effects of centipede].

Our experiment has shown that the aqueous extract of Centipede can markedly decrease the contents of lipid peroxide in the serum as well as lipofuscin in the liver tissues and brain tissues of rats, enhances the activity of superoxide dismutase in erythrocyte and glutathione in blood, but has no action on the lipofuscin in the heart. In addition, the extract is able to increase the weight of spleen and thymus.

Aging↗
PubMed1993

Vaginal reconstruction with an island flap of the inferior epigastric vascular pedicle.

This paper presents a new method of vaginal reconstruction. On the basis of anatomic study, we designed an island flap obtained from the upper abdomen to carry the deep inferior epigastric vasculature. At operation, the flap was transferred to the artificial cavity created between the urinary bladder and rectum for vaginal reconstruction. Eight patients received the operation. Complete survival of the flap occurred in seven patients, and one flap failed because of a twist in the flap vascular pedicle. During a follow-up of 6 months to 2 years, it was found that the reconstructed vaginal wall was not only soft but also elastic, and the patients were able to have a satisfying sexual life after marriage.

Adult↗