Biomedical subjects
Publications and source records attributed to Y B Zhang.
According to the pharmacological results five compounds were isolated from the herb of Commelina communis. Based on physico-chemical constants and spectral data, four of them were identified as n-triacontanol, p-hydroxycinnamic acid, daucosteril and D-mannitol. p-hydroxycinnamic acid shows antibacterial activity and D-mannitol shows antitussive effect.
The heart is a target organ for parathyroid hormone (PTH), and the action of this hormone on the myocardium may be mediated through the ability of PTH to increase cytosolic calcium ([Ca2+]i) in the myocardial cells. However, direct evidence for such an effect of PTH is lacking, and the mechanism(s) through which the hormone can potentially exert such an effect have not been elucidated. In the present study these questions were examined using cardiac myocytes isolated from adult rats. Both PTH-(1-34) and PTH-(1-84) produced a dose-dependent increase in [Ca2+]i of myocytes, but the effect of the latter was significantly (P < 0.01) greater than the former. This action of PTH was abolished by the inactivation of the hormone, the use of a PTH antagonist, or by verapamil. The G protein activator, guanosine 5'-O-(3-thiothriphosphate) (GTP gamma S), mimicked the effect of PTH, whereas pertussis toxin, the G protein inhibitor, guanosine 5'-O-(2-thiodiphosphate) (GDP beta S), or ryanodine significantly reduced the PTH-induced rise in [Ca2+]i. Dibutyryl- and 8-bromoadenosine-3',5'-cyclic monophosphate, forskolin, 12-O-tetradecanoylphorbol 13-acetate, and staurosporine did not increase [Ca2+]i in myocytes, and staurosporine did not alter the PTH-induced rise in [Ca2+]i. BAY K 8644 augmented the effect of PTH on [Ca2+]i. These data demonstrate that 1) PTH increases [Ca2+]i of cardiac myocytes, 2) this action is receptor mediated and is produced by activation of the L-type calcium channels following stimulation of G protein(s), and 3) the rise in [Ca2+]i is due to both augmented entry of calcium into the myocytes and mobilization of calcium from sarcoplasmic reticulum by a calcium-induced calcium release mechanism.
BACKGROUND AND METHODS: Patients with Parkinson's disease tend to have a reduced response to levodopa after 5 to 20 years of therapy, with "on-off" fluctuations consisting of dyskinesia alternating with immobility. In an effort to modify the motor disability of advanced Parkinson's disease, we implanted embryonic mesencephalic tissue containing dopamine cells into the caudate and putamen of seven patients. Two patients received unilateral grafts in the caudate and the putamen on the side opposite the side with worse symptoms. Five patients received bilateral grafts implanted in the putamen only. In six of the seven patients, the fetal tissue was obtained from a single embryo with a gestational age of seven to eight weeks. The tissue was injected by means of 10 to 14 needle passes. There were no surgical complications. Four of the seven patients underwent immunosuppression with cyclosporine and prednisone. RESULTS: All patients reported improvement according to the Activities of Daily Living Scale when in the on state 3 to 12 months after surgery (P < 0.01). Neurologic examination according to the Unified Disease Rating Scale showed that five of the seven patients improved when in the on state six months after surgery. The mean group Hoehn-Yahr score improved from 3.71 to 2.50 (P < 0.01). Computer and videotape testing in the home supported these findings. Fluctuations in clinical state were moderated, and periods of dyskinesia and off episodes were shorter and less severe than before implantation. Drug doses were reduced by an average of 39 percent (P < 0.01; maximum, 58 percent). The results of clinical evaluation and fluorodopa positron-emission tomography in one patient were compatible with transplant survival for as long as 46 months. Both immunosuppressed and nonimmunosuppressed patients improved. CONCLUSIONS: Fetal-tissue implants appear to offer long-term clinical benefit to some patients with advanced Parkinson's disease.
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A genetic system for directly synthesizing eukaryotic membrane proteins in Escherichia coli and assessing their ability to insert into the bacterial cytoplasmic membrane is described. The components of this system are the direct expression vector, pYZ4, and the mature beta-lactamase (BlaM) cassette plasmid, pYZ5, that can be used to generate translational fusions of BlaM to any synthesized membrane protein. The beta-subunit of sheep-kidney Na,K-ATPase (beta NKA), a class-II plasma membrane protein, was synthesized in E. coli using pYZ4, and BlaM was fused to a normally extracellular portion of it. The fusion protein conferred ampicillin resistance on individual host cells, indicating that the BlaM portion had been translocated to the bacterial periplasm, and that, by inference, the eukaryotic plasma-membrane protein can insert into the bacterial cytoplasmic membrane. A series of 31 beta NKA::BlaM fusion proteins was isolated and characterised to map the topology of the eukaryotic plasma membrane protein with respect to the bacterial cytoplasmic membrane. This analysis revealed that the organisation of the beta NKA in the E. coli cytoplasmic membrane was indistinguishable from that in its native plasma membrane.
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Three strains of B. thetaiotaomicron have been isolated from caeca of BALB/c-nu/+ mice of SPF. These Bacteroides are obligately anaerobic, Gram-negative, non-spore-forming and non-motil without flagella rods. A characteristic of staining is deep at ends and stainless at the medium of a rod. The isolation and identification of these strains has been reported in 1987. This paper introduced only the results of EM observations. Under the SEM, the unstained area of rods is always showing a concavity, which is just a nucleoid in sections under the TEM. Many lamellar corpuscles have been found in cell plasma. Some of them have been secreted out of the cells. The chemical properties and physiological functions of them are unknown.
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UNLABELLED: The purpose of this study was to evaluate the usefulness of 99mTc-MIBI scintinammography for the detection of breast cancer. METHODS: Sixty-one consecutive patients referred for a suspicions breast lesion on clinical examination were studied with 99mTc-MIBI scintimammography. There were 60 female patients and 1 male patient with 63 pulpable breast abnormalities. Each patient received 20mCi 99mTc-MIBI intravenously. Ten and 120 minutes postinjection, three planar views, right and left lateral prone and anterior supine thoracic views, were obtained. The patient underwent surgery within one week and the final diagnostic results (histopathology) were obtained. RESULTS: Thirty-two of 63 abnormalities of breast were pathologically confirmed breast cancer, and 31 were benign lesions. In the group of patients studied, the sensitivity of 99mTc-MIBI scintimammography was 78.1% (25 true-positive, 7 false-negative) and the specificity was 90.3% (28 true-negative, 3 false positive). The positive predictive value was 89.3%, the negative predictive value was 80.0%, the positive likelihood ratio was 8.1, the negative likelihood ratio was 0.2. CONCLUSION: This study showed the high diagnostic accuracy of 99mTc-MIBI scintimammography in detecting breast cancer. 99mTc-MIBI scintimammography can be used as an assistant method to non-invasively assess breast cancer invasiveness before surgery.
In order to study the effects of isovolumic hemodilution and its combination with Danshen solution on acute ischemic reperfused canine myocardium, 24 adult hybrid dogs were used and divided into four groups. Group I was the control group, groups II-IV were treated with Dextron 40, Danshen solution and a combination of the two, respectively. The results showed that either Dextron 40 or Danshen solution alone had a significant increase of +/- dp/dt-max when compared with group I (p < 0.05). Although no significant difference existed between group II and III, the former showed more rapid action. The combination of the two therapies improved +/- dp/dt-max and LVSP, and significantly reduced the necrotic sizes and the MDA contents in the ischemic myocardia compared with not only group I, but also group II or group III (all p < 0.05). The results suggest that isovolumic hemodilution or Danshen may protect the ischemic reperfused myocardium and the former may come into action more rapidly, and that the combination of the two may show a better synergism than each one of the two by itself.