Biomedical subjects

C Zhang

Publications and source records attributed to C Zhang.

At least 613 records · Page 34Linked to original sources

PubMed1995

Microdialyzed adenosine in nucleus tractus solitarii and ventilatory response to hypoxia in piglets.

Levels of adenosine, inosine, and hypoxanthine from the interstitial space at the nucleus tractus solitarii were measured by microdialysis in eight 20- to 25-day-old anesthetized spontaneously breathing piglets. Microdialyzed samples were collected every 30 min for 2 h after the insertion of the probe to ensure stability of purine levels and then during 30 min each of normoxia, hypoxia (10% O2-90% N2), and normoxia. The purines were separated by high-pressure liquid chromatography with ultraviolet detection and quantified at 254-nm wavelength. Tidal volume, breathing frequency, minute ventilation, mean arterial blood pressure, pH, and gas tensions were measured. Compared with control, adenosine levels during hypoxia increased by 40.7 +/- 5.5% and then tended to decline during the recovery from hypoxia, but the levels remained higher than in control. Ventilatory measures exhibited a modest biphasic pattern during hypoxia and resumed control values by 10 min after the removal of the hypoxia. The increased adenosine release during hypoxia provides additional evidence for the possible participation of adenosine in the central suppression of breathing during hypoxia.

Adenosine↗

PubMed1995

Delayed dystonia with striatal CT lucencies induced by a mycotoxin (3-nitropropionic acid).

We describe a clinical syndrome of delayed dystonia in children subsequent to initial gastrointestinal symptoms and acute noninflammatory encephalopathy. The syndrome was caused by the ingestion of mildewed sugarcane containing the Arthrinium-produced mycotoxin, 3-nitropropionic acid (3-NPA). In the severely affected patients, intoxication usually was heralded by coma, with dystonia appearing 7 to 40 days after recovery from the coma. The dystonia was manifested as choreoathetosis, torsion spasms, or painful paroxysmal spasms of the extremities and was neither progressive nor reversible. CTs of the dystonic patients consistently showed bilateral hypodensities in the lenticular nuclei. The pathogenesis of the selective lenticular lesions induced by 3-NPA is not yet clear.

Carbohydrates↗

PubMed1995

Morphometric analyses and aging process of nerve fibers in the human spinal posterior funiculus.

The aim of the present study is to evaluate the size and number of axons in the human spinal cord nerve fibers according to the aging process, and, after conducting morphometry of histology preparations at different ages, to show some of the effects of aging on those fibers. We examined thirty-eight human spinal cords which had been taken from cadaver specimens (25 males and 13 females) aged from 41 to 97 years. The spinal segments were embedded in celloidin and sections were stained with Luxol fast blue-periodic acid-Schiff-hematoxylin (LPH). Highly enlarged images with a square eyepiece grid and oil-immersion lens were used to count the myelinated axons and to measure the axon transverse area in a unit area of the posterior funiculus at C6 level, with the help of a microscope equipped with a drawing tube, an electronic optical planimeter and a computer. Significant age-related linear decreases were found for all parameters. Our report may provide new information concerning the aging process of the human spinal cord. It revealed that a decrease in size and number of axons were one of the important changes occurring with the aging process in the human spinal posterior funiculus.

Adult↗

PubMed1995

[Modifications of gene expression by tumor promoters].

The modifications of gene expression by tumor promoters were analyzed in vitro and in vivo. The results of slot blot hybridizations showed that tumor promoter TPA induced c-fos and c-myc expressions in mouse fibroblast cell line BALB/3T3 and rat liver, decreased the levels of Rb RNA in BALB/3T3 cell line and of alpha 1-I3 RNA in rat liver. It was also demonstrated that tumor promoter phenobarbital influenced c-fos and c-myc expressions and decreased alpha 1I3 mRNA level in rat liver during a long term experiment. Phenobarbital was found to have no effect on c-fos and c-myc expressions in rat liver during a short experiment. Tumor promoters induced the expressions of c-fos and c-myc which were positively-related to cancer formation and inhibited the expressions of Rb and alpha 1-I3 which were negatively-related to cancer formation. This implied that tumor promotion played an important role in cancer development and tumor promoters exerted their effects selectively according to the attributes of different genes.

3T3 Cells↗

PubMed1995

[Sensitivity of Plasmodium falciparum to seven antimalarials in China-Laos border].

The sensitivity of P. falciparum to chloroquine (CHL), piperaquine (PIP), artesunate (ATS), dihydroartemisinine (DAT), artemether (ATM), arteether (ATE) and pyronaridine (PRN) were assayed by in vitro microtechnique in China-Laos border in 1992. The resistance rates of isolates from the south of Yunnan of China in the border were 97.0%, 96.4%, 12.5%, 16.0%, 6.3% and 34.5%, respectively; ID50 were 119.0, 320.0, 7.2, 5.4, 295.0, 74.4 and 31.9 nmol/L, ID95 were 625.0, 2426.0, 42.2, 36.6, 767.0, 371.1 and 325.2 nmol/L. The resistance rates of isolates from the north border of Laos were in order 9/10, 8/10, 1/5 to CHL, PIP, PRN, ID50 were 114.0, 166.9, 16.4 nmol/L, ID95 were 570.0, 631.1 and 107.7 nmol/L. All the isolates from Laos were sensitive to ATS, DAT, ATM and ATE. ID50 were 5.0, 4.4, 91.6 and 56.7 nmol/L, ID95 were 23.4, 11.1, 3276.1 and 223.9 nmol/L, respectively. The results indicate that P. falciparum in the border was highly resistant to CHL and PIP, while most of the isolates were susceptible to the other 5 of the above-mentioned drugs. A comparison between the isolates from China and Laos showed that there was no significant difference in resistance degree to CHL but the sensitivity of isolates from China to other 6 drugs was lower than those from Laos.

Animals↗

PubMed1995

[Surgical treatment of colonic and rectal cancer with hepatic metastasis].

In 568 patients with colonic and rectal cancer treated in our hospital from January 1970 to January 1991, 266 had colonic cancer and 302 rectal cancer. 469 patients (263 rectal and 233 colonic) were operated on. A total of 382 patients (186 and 196 colonic) were resectable. The average resection rate was 76.6%. 68 patients (30 rectal and 38 colonic) had hepatic metastasis with a rate of 11.97%. 13 patients (19.1%) had hepatic metastasis focus resected.

Adult↗

PubMed1995

[Successful replantation in ten-digit complete amputation: a case report].

We report a case of successful replantation of ten-digit complete amputation. The conditions of the wounds over the ends of the ten amputated digits varied from severe to light and easy for replantation. The amputation included severe avulsion injuries over four fingers. Appropriate measures were taken during surgery and the replanted digits all survived. The replantation operation was done by a team of surgeons. Although the surgeons were physically challenged by the long and difficult procedures, they worked hard for the benefit of the patient. Physiotherapy and exercises six months after operation showed that the functions of both hands were largely recovered.

Adult↗

PubMed1995

[Detection of hepatitis C virus RNA and C33c antigen in the liver tissue from hepatitis C virus infection patients with chronic liver disease].

To study the distribution of hepatitis C virus (HCV) in liver tissue and its pathogenesis, nonisotopic in situ hybridization with a digoxin labelled cDNA probe to 5'-NC region of HCV and immunohistochemical study with monoclonal anti-body of anti HCV C33c were performed on the liver tissue from 24 HCV infection patients with chronic liver disease. The results were as follows: In the liver tissue of 17 patients with HCV infection (both ELISA anti-HCV and nested PCR HCV RNA positive in serum), the positivity of HCV RNA and C33c were 82.3% (14/17) and 88.2% (15/17) respectively. In 7 patients with anti-HCV positive only HCV RNA was not detected in the liver tissue, but 4 out of these 7 cases were C33c positive. The specific signals of HCV RNA and C33c were mainly localized in the cytoplasm of hepatocytes. The distribution of the HCV infected hepatocytes was spotty, scattered or diffuse. There was no relationship between the distribution and the level of alanine transaminase or pathologic changes in liver. There were many lymphocytes and monoclear cells infitrating the periphery of HCV-infected liver cells. The results suggested that replication of HCV in the cytoplasm of hepatocytes elicits the host immune response in cells infected with HCV and this is important in the pathogenesis of HCV infection.

Adult↗

PubMed1995

[Studies on inactivation of hepatitis B virus with polymerase chain reaction].

Polymerase chain reaction-ethidium bromide (PCR-EB) method for detecting hepatitis B virus DNA (HBV-DNA) was established with good specificity and a detection limit of 1 pg HBV-DNA, minimum HBV infection dose in susceptible animal, chimpanzees, could be detected with it. Determination of inactivation of HBV-DNA could be inactivated with active chlorine 1,250 mg/L for 60 minutes, or 2,500 mg/L for 30 minutes, 10 pg HBV-DNA in purified Dane particles could be inactivated by active chlorine 625 mg/L for 10 minutes. Accordingly, use of PCR to evaluate the effects of chlorine disinfectant in inactivating HBV was feasible, and HBV-DNA was a more reliable index for inactivation of HBV than HBsAg.

Base Sequence↗

PubMed1995

[IgG RF analysis of supernatant of cultured synovia in patients with rheumatoid arthritis].

We used Enzyme Linked Immuno-Sorbent Assay (ELISA) to measure IgG RF of supernatant of cultured knee synovia in 45 patients with various rheumatic diseases (Harvest time for the supernatant was 1,4,7,14,28 days). 25 cases of patients with osteoarthritis (OA) and non-synovitis (Non-S) were regarded as the negative control. IgG RF was positive in 4 of 12 patients with rheumatoid arthritis (RA), whose IL-1 bioactivity is also high. Meanwhile these 4 patients had not received disease-modifying anti-rheumatic drugs (DMARDs) and their clinical and laboratory parameters were active. IgG RF was negative in other groups. It is suggested that humoral factor such as IgG RF and cytokine such as IL-1 may play the synergistic role in the pathogenesis of RA and DMARDs may suppress these two kinds of pathological factors.

Adult↗

PubMed1995

[Long-term follow-up of allotransplantation of retinal pigment epithelial cells in rabbit with special reference to morphological studies].

Dysfunction as well as pathological changes of retinal pigment epithelium (RPE) has been implicated as the causes of some retinal diseases, including age-related macular degeneration, hereditary macular degeneration and retinitis pigmentosa, etc. Transplantation of normal healthy RPE cells with an attempt to treat the retinal diseases is one of the current interests in ophthalmic research. We have developed a modified pars plana technique including vitrectomy for subretinal transplantation of homologous, cultured, natural pigment labelled RPE cells in the non-pigmented rabbit. Our results, with follow-up from one week to one year, revealed that the transplanted RPE cells not only survived and attached to Bruch's membrane of the host eyes, but also had a distinct basal and apical morphology as seen in close contact with host photoreceptors, and formed junctional complexes with neighboring RPE cells. Close contact between the microvilli of the grafted RPE cells and the photoreceptor outer segments of the host was also observed. The normal periodical sheddings of the host outer segments were phagocytosed by the transplanted RPE cells, as demonstrated in our results. Furthermore, there was practically no, if any, sign of rejection found. All the results have demonstrated that the transplantation of RPE cells in rabbits was successful and these observations provide a reliable experimental evidence for the clinical research of allotransplantation of RPE cells.

Animals↗

PubMed1995

[Study on the optimums for Pseudomonas maltophilia HCG receptor expression].

According to the design of orthogonal experiment, the optimums for expression of Pseudomonas maltophilia with HCG receptor were studied by radioassay. The results showed that the optimums influencing the specific binding percentage of Pseudomonas maltophilia were the cultures of No. 3 solid medium added with 0.5% galactose and incubated at a temperature of 37 C for 72 hours. Under these conditions, the binding percentage of Pseudomonas maltophilia to HCG was higher than those under other conditions.

Pseudomonas↗

PubMed1995

A novel metabotropic glutamate receptor expressed in the retina and olfactory bulb.

A novel metabotropic glutamate receptor, mGluR8, was identified by screening a mouse retina cDNA library. This receptor is most related to mGluR4, mGluR7, and mGluR6 (74%, 74%, and 70% identical amino acid residues, respectively). Similar to these receptors, stimulation by L-glutamate or L-2-amino-4-phosphonobutyrate (L-APB) of Chinese hamster ovary (CHO) cells stably transfected with mGluR8 result in the inhibition of forskolin-stimulated adenylyl cyclase. In situ hybridization studies revealed a strong expression of the mGluR8 gene in the olfactory bulb, accessory olfactory bulb, and mammillary body. A weaker expression was found in the retina, and in scattered cells in the cortex and hindbrain. During development, the distribution of mGluR8 expression was more widespread. These results extend the diversity of metabotropic glutamate receptors in the CNS. Because at least two APB receptors are expressed in the retina, the use of this drug to block selectively the ON pathway needs to be reconsidered. The pharmacology and expression of mGluR8 in mitral/tufted cells suggest it could be a presynaptic receptor modulating glutamate release by these cells at their axon terminals in the entorhinal cortex.

Amino Acid Sequence↗

PubMed1995

Brain activity of a rat reflects apparently the stimulation of acupuncture. A radioautography using 2-deoxyglucose.

To confirm a relationship between the central nervous system and the acupuncture, the response was examined in the rat brain using radioautography with tritiated 2-deoxyglucose, after stimulation of some acupoints. Eight groups, of a total of 27 rats were submitted to acupuncture at 6 different acupoints (Zusanli, Renzhong, Tianshu, Shenmen, Neiguan, Yongquan) and control, with or without electric pulses or with anesthesia respectively, prior to the injection with isotopic deoxyglucose. A hundred twenty cryosections were cut from a freshly frozen brain and exposed on single-coated X-ray films. The results showed that the acupuncture on the four acupoints of Zusanli, Tianshu, Shenmen and Neiguan enhanced the activity of the neocortex, the limbic cortex and the thalamic nuclei in comparison with the control group. The acupoints on Renzhong and Yongquan depressed the activity on the thalamic nuclei and the midbrain. The anesthesia with pentobarbital concealed the most activity on the whole area of the brain, which hardly responded to any stimulation of acupuncture. These results lead to the suggestion that the brain may reflect the signals by the stimulation of acupuncture and change the activity depending upon each acupoint.

Acupuncture Therapy↗

PubMed1995

[Preparation method for compound Hirudo oral liquid].

The extraction efficiency of alcohol, water and alcohol followed by water for Hirudo and the principal constituents of compound Hirudo oral liquid were compared with the extraction rate of nitric substances and pharmacological activity as the evaluation marker. Based on results of the above experiments, a new preparation method for the oral liquid was established.

Animals↗

PubMed1995

[Pathological changes in the livers of rabbits infected with schistosome cercariae and treated with artemether or praziquantel in the early stage of infection].

When rabbits infected with Schistosoma japonicum cercariae for 7 d were treated ig with artemether (Art) 30 mg.kg-1, and repeated at 1-wk intervals (i.e. on d 14, 21, 28 after infection) for 4 times, dead worms were found in the liver sections, but no egg or egg granuloma was detected. In infected rabbits treated repeatedly with the above-mentioned dosage of Art at 2-wk intervals (i.e. on d 21, 35, 49) after the first dosing on d 7 after infection, few eggs and egg granulomas were seen occasionally. In another experiment, praziquantel (Pra) 40 mg.kg-1 was given ig to rabbits on d 21 after infection and the same dosage was administered repeatedly at 1- or 2-wk intervals for 2 times, the numbers of eggs and egg granulomas detected in the liver sections of these 2 groups were much less as compared with the control. In the latter group treated at 2-wk intervals, only degenerated eggs and egg granulomas were detected occasionally in the liver sections. The results indicate that if Art or Pra was given to rabbits in the early stage after infection, no apparent or only slight damage of the liver induced by the eggs was seen due to the fact that most or even all of the female worms were killed.

Animals↗

PubMed1995

Biological activity assays of cell-free reassembled nuclei--injecting cell-free reassembled nuclei into unfertilized eggs can induce the eggs to cleave and reconstitute asters, and the injected nuclei undergo cell cycle changes.

Nucleus may reassemble spontaneously in cell-free mixture of HeLa metaphase chromosomes, Xenopus egg extracts and ATP-regenerating system, and the nucleus shows some biological activities. It is found that, after being injected into unfertilized mature eggs, the cell-free reassembled nuclei can cause the eggs to cleave and reconstitute asters in their cytoplasm, and the injected nuclei undergo changes in response to cell cycle regulators stored in the eggs, and that reinjecting cytostatic factors (CSF) into the eggs can stabilize the eggs in mitotic phase, cause the nuclei disassembly and chromatin condensation to chromosomes.

Animals↗

PubMed1995

[A clinical and experimental study of L-form bacteria in 66 cases].

In order to study the relationship between the time for establishing the diagnosis of infectious diseases and L-form bacteria, a series of clinical specimens taken from 321 cases of patients suspected to have infection were collected. Besides routine bacterial culture, special culture for L-form bacteria was also performed. The results were as follows: the rate of positive routine bacterial culture was 10.90% (35/321); the rate of negative routine bacterial culture but positive L-form bacterial culture was 20.56% (66/321). In this study, L-form bacteria infection was treated with sensitive antibiotics and a satisfactory result was obtained. It is shown that L-form bacterial culture is very useful in detection of pathogenic bacteria and helpful to the therapy of infectious diseases. Ultrastructure organization of these bacteria was studied by using transmission electron microscope.

Adult↗