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Biomedical subjects

Y Lin

Publications and source records attributed to Y Lin.

At least 631 records · Page 35Linked to original sources
PubMed1991

A myosin-like protein from smooth muscle.

A protein was purified from chicken gizzard smooth muscle. It bound ATP and actin. Actin activated the Mg2(+)-ATPase activity of this protein. The Ca2(+)-ATPase activity was lower than K(+)-EDTA ATPase activity. Thus, it appears that this protein is akin to myosin I rather than to conventional myosin. However, ATPase activities of the protein were much lower than those of myosin I. A protein cofactor, such as protein kinase, which would enhance these activities remains to be purified from the smooth muscle.

Actins↗
PubMed1991

[Activity of 5 alpha-reductase in human hyperplastic prostates].

To Study the relationship between the activity of 5 alpha-reductase and benign hyperplastic prostate (BPH), we have measured the T and dihydrotestosterone (DHT) contents and the specific activity of this enzyme in mechanically separated stroma and epithelium and in both the nucleus and cytoplasm from 20 cases of BPH and 7 cases of normal human prostate. The results were as follows: (1) The content of DHT in the BPH group was about 3 times higher than that in the N group. (2) The Michaelis constant (Km) of 5 alpha-reductase in both the stroma and epithelium was similar. (3) The specific activity of the enzyme in the stroma was higher than that in the epithelium, and in the BPH group, increased activity was found in the tissue or stroma but not in the epithelium. The activity was predominant in the nucleus. So our experiment supports that the elevation of the activity of 5 alpha-reductase may be related to the pathogenesis of human BPH.

Aged↗
PubMed1991

[Synthesis of delta virus cDNA of China Sichuan strain].

delta virus cDNA of China Sichuan strain, 1.2 kb in length, was synthesized by extraction of RNA from liver tissue in a patient with subacute severe hepatitis, followed by reverse transcription and polymerase chain reaction (RT-PCR). The result was confirmed by Southern blot hybridization using 32P and biotin labelled delta virus cDNA (HN88, cloned in USA) probes respectively.

Blotting, Southern↗
PubMed1990

Chronic caffeine exposure reduces the excitant action of acetylcholine on cerebral cortical neurons.

Chronic administration of caffeine (s.c. for a period of 14 days in escalating doses of 10-70 mg/kg) decreased the sensitivity of rat cerebral cortical neurons to the excitant action of microiontophoretically applied acetylcholine. The sensitivity of spontaneously firing rat cerebral cortical neurons in caffeine-treated animals was compared with that of saline-treated controls using the same multiple barrel micropipettes tested on the same day. Acetylcholine sensitivity was determined by the E.T50 method. The E.T50 for 71 neurons in the caffeine-treated rats of 224.0 +/- 11.3 (S.E.M.) was significantly (P less than 0.001) greater than that of 65 neurons in the saline-treated control rats (153.8 +/- 6.9), indicating a reduction in the excitant action of acetylcholine on neurons which had been chronically exposed to caffeine. The level of spontaneous activity was also reduced in the caffeine-treated animals. A down-regulation of acetylcholine receptors is a possible cause for these effects.

Acetylcholine↗
PubMed1990

Chronic caffeine exposure enhances adenosinergic inhibition of cerebral cortical neurons.

Chronic administration of caffeine (s.c. for a period of 14 days in escalating doses of 10-70 mg/kg) increased the sensitivity of rat cerebral cortical neurons to the inhibitory action of microiontophoretically applied adenosine. The sensitivity of spontaneously firing rat cerebral cortical neurons in caffeine-treated animals was compared with that of saline-treated controls using the same multiple-barrel micropipettes tested on the same day. Adenosine sensitivity was determined by the I.T50 method. The I.T50 value for 134 neurons in the caffeine-treated rats of 130.77 +/- 4.33 (S.E.M.) was significantly (P less than 0.001) different to that of 136 neurons in the saline-treated control rats (222.16 +/- 6.68), indicating a supersensitivity to adenosine in neurons which had been chronically exposed to caffeine.

Adenosine↗
PubMed1990

Lateral sural cutaneous artery island flap in the treatment of soft tissue defects at the knee.

This paper describes a flap for covering defects around the knee. Dissections of 20 legs showed that in the majority the lateral sural cutaneous artery branched from the popliteal artery and descended along the posterolateral aspect of the leg together with two venae comitantes and the lateral sural cutaneous nerve. An island flap was designed, pedicled on these vessels and nerve, and was used in 17 patients with defects around the knee, including acute trauma (three cases), soft tissue tumours (three cases), unstable scar or ulcer (seven cases), and chronic osteomyelitis or infected open fractures with tissue loss (four cases). All the flaps survived entirely and possessed normal sensation. Furthermore, it was not necessary to sacrifice the main vessels of the lower leg.

Adolescent↗
PubMed1990

Ultrastructural analysis of regional type II cell development within fetal and neonatal lungs.

Type II cells within guinea pig lungs were studied beginning when lamellar bodies (LB) were first identifiable, to determine the pattern of their ultrastructural maturation through parturition and to search for regional differences suggested for other species in their numbers or maturity within the same lung. Fetuses were examined at gestational ages of 55, 60, and 65 days, as were newborn within 2 h of birth at 68 days. The stratified sampling system divided left lungs into nine blocks from each cranial and caudal lobe for electron-microscopic morphometry. Type II cells were compared among blocks within lobes, between lobes within age groups, and among ages for volume densities [VV(ep2, t)], numerical densities [NV(ep2, t)], and surface densities [SV(ep2, t)] per block; total tissue volumes [V(ep2)], numbers [N(ep2)], and cumulative surface areas [S(ep2)] per lung; and the VV(lb, ep2) and V(lb) of their LB. Within lobes, there were no significant differences among blocks for any parameter. Within age groups, significant interlobar differences were limited only to NV(ep2, t) (cranial greater than caudal at day 55, P less than 0.001). In age-by-age comparisons, the V(ep2), NV(ep2), and S(ep2) each increased dramatically from day 55 to 60 (P less than 0.001) but then remained unchanged through parturition. However, both VV(lb, ep2) and V(lb) increased linearly with fetal age (day 55 less than 60 less than 65 less than newborn), with VV(lb, ep2) achieving 18% type II cell volume in the postpartum group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Multiple malignant tumors combined with oral cancer from annual of the pathological autopsy cases in Japan, 1984-1988].

During the 5-year period from 1984 to 1988, a total of 944 cases had been presented multiple (3 or more) primary malignant tumors in annual of the pathological autopsy cases in Japan. Forty-one cases (4.3%) had lip and oral cancer. Of this group, triple were described 36 cases, quadruple 3 cases and more discrete multiple 2 cases, respectively. It is more frequent in men than in women, the ratio being 12.7:1. The age range is from 34 to 86 years with a mean of 66.9 years. In these cases with oral cancer, the another primary site is almost always found in digestive system (90.2%), e.g. esophagus (36.6%), stomach (34.1%) and colon and rectum (34.1%).

Adult↗
PubMed1990

Hepatitis B virus-associated hepatocellular carcinoma in African patients.

We have examined several tumors from South African patients with hepatitis B virus (HBV)-associated hepatocellular carcinoma for the presence of integrated viral DNA. In contrast with our findings in patients from Taiwan, few copies of the viral genome were integrated in each tumor. Furthermore, Southern hybridization showed similarities in integration patterns between different tumors. We are presently constructing genomic libraries from selected single-copy tumors in order to make a more detailed analysis of HBV DNA integration at the molecular level.

Africa↗
PubMed1990

The reverse-flow posterior tibial artery island flap: anatomic study and 72 clinical cases.

Based on anatomic, dye injection, and angiography observations since 1984, 72 patients with tissue defects of the foot (due to injury or surgery) have been reconstructed using a reverse-flow posterior tibial artery island flap. In the 72 patients, etiology has included extensive crushing (40 patients), burn scars (10 patients), and tissue loss following tumor or chronic ulcer resection (22 patients). Only two flaps developed necrosis. The survival rate was 97.2 percent, including seven cases of distal marginal necrosis. This procedure, therefore, offers a useful alternative in the repair and reconstruction of extensive tissue defects in the foot, whether caused by accidental injury or surgery.

Adolescent↗
PubMed1989

Cocaine: evidence for supraspinal, dopamine-mediated, non-opiate analgesia.

Cocaine (25 mg/kg i.p.) produces analgesia in the rat within 5 min and for a duration of 90 min as determined by the formalin test or for 30 min as determined by the hot plate test. Cocaine analgesia is unaffected by doses of naloxone that are sufficient to attenuate morphine analgesia in both tests. Chlorpromazine (3 mg/kg i.p.), SCH 23390 (100 micrograms/kg i.p.; a D1 dopamine receptor antagonist), and eticlopride (75 micrograms/kg i.p.; a D2 dopamine receptor antagonist) each attenuate cocaine analgesia in both tests at doses that alone do not affect performance in either test. Measurements of blood pressure and heart rate indicate that cocaine analgesia is not due to the activation of baroreceptor reflex afferents. We conclude that cocaine is a supraspinally acting, dopamine-mediated, non-opiate analgesic in the rat.

Analgesia↗
PubMed1989

Cell lines cultured at high density are resistant to lysis by tumor necrosis factor and natural cytotoxic cells.

It has been suggested that natural cytotoxic (NC) cell activity and tumor necrosis factor (TNF), the molecular mediator of NC activity, are capable of protecting individuals against the progression of incipient tumors or could be useful in cancer therapy regimens. Much of this speculation arises as a result of in vitro studies, on a variety of tumor cells, demonstrating the cytolytic and cytostatic properties of NC and TNF activities. Here, evidence is presented showing that certain mouse fibroblast cell lines, generally considered sensitive to NC and TNF lysis, are quite resistant to these lytic activities when cultured at high cell density. Although a soluble factor that renders these same target cells resistant to NC and TNF lysis has been described, no such factor is involved in this high density-induced resistance. Rather, it appears that cell to cell contact of the targets is critical. Moreover, the induced resistance to NC and TNF lysis does not result from loss of either NC recognition determinants or TNF receptors by the target cells, but is the consequence of increased expression of a protein synthesis-dependent resistance mechanism. These observations raise the issue of the in vivo phenotype of cells characterized in vitro as sensitive to NC and TNF lysis. It is entirely possible that certain cells which are considered sensitive to NC and TNF activities are, in fact, resistant to these cytolytic activities when growing as tumors (i.e., at high cell density). Should this be the so, NC and TNF cytolytic activities may not function in vivo or may function only via some indirect means.

Animals↗
PubMed1989

A hygienic survey of the environment of underground space and buildings.

Full utilization of underground space and buildings could have positive economic and social effects. However, the microclimate and air quality must be well controlled so that they are not harmful to human health. This survey indicated that relative humidity is a common hygienic problem in underground space and buildings. Attention should be paid to humidity control and to the strengthening of routine ventilation at the construction stage. Carbon dioxide can be used as a hygiene index of air pollution: the sanitary standard for it in the air of underground buildings is 10%. The hygienic survey shows that the concentration of carbon dioxide is usually below this standard in the environments of underground space and buildings.

Air Movements↗