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S S Yang

Publications and source records attributed to S S Yang.

At least 163 records · Page 9Linked to original sources
PubMed1985

Somatosensory evoked potentials in hepatic encephalopathy.

Median nerve somatosensory evoked potentials were recorded from 33 patients with various degrees of hepatic failure and from 10 age-matched controls. Within 20 ms poststimulation, one negative peak (N13) could be recorded from the middle of the back of the patient's neck at the C2 vertebral level. Within 150 ms, three negative and three positive peaks, sequentially designated as N1, P1, N2, P2, N3, and P3, could be recorded from the scalp over the contralateral sensory cortex. There was a progressive prolongation of peaks and interpeak latencies correlating with the severity of hepatic encephalopathy. In 10 patients with hepatic failure but no clinical evidence of hepatic encephalopathy, latencies of peak N3 and P3 were delayed and N1-N3 interpeak latencies were prolonged. Thirteen patients with grade 1 or 2 hepatic encephalopathy showed further delayed latencies of peaks P2, N3, and P3, further prolonged N1-N3, N1-P2 interpeak latencies, and distortion of waveforms. Peaks N2, P2, N3, and P3 were further delayed, and even disappeared in 10 patients with grade 3 or 4 hepatic encephalopathy. However, central conduction time (N13-N1 interpeak latency) was not prolonged in all stages of hepatic failure. In addition, serial somatosensory evoked potential studies correlated well with the clinical course. The present data suggest that somatosensory evoked potential recording is a reliable objective method in the early assessment and monitoring of hepatic encephalopathy.

Adolescent↗
PubMed1985

Acute exacerbation in hepatitis B e antigen positive chronic type B hepatitis. A clinicopathological study.

During a 6-year (mean 24.5 months) follow-up study of 237 HBeAg-positive patients with biopsy-verified chronic type B hepatitis, 199 episodes of acute exacerbation (SGPT greater than 300 IU/l) were observed in 148 patients. The clinical and laboratory findings of these acute exacerbations were less severe than classic acute viral hepatitis (P less than 0.001) but with remarkable overlapping. The main histological changes of acute exacerbations were those of lobular hepatitis, even with bridging hepatic necrosis which predicted subsequent HBeAg clearance. Anti-HBc IgM was positive in 14.4% of the exacerbations. All of these findings made acute exacerbation of chronic type B hepatitis indistinguishable from acute viral hepatitis aside from chronic clinical history. Hepatitis A virus, delta agent and possibly non-A, non-B virus(es) were responsible for some of the episodes of clinical exacerbations.

Acute Disease↗
PubMed1985

Hemodynamic and anesthetic effects of sufentanil as the sole anesthetic for pediatric cardiovascular surgery.

The efficacy, safety, and hemodynamic response to 5 micrograms/kg, 10 micrograms/kg, or 20 micrograms/kg of sufentanil and 0.1 mg/kg pancuronium was evaluated in children between 4 and 12 years of age scheduled for open heart surgery. Systolic time intervals, 2-D echocardiograms, systolic blood pressures (SBP), diastolic blood pressures (DBP), and heart rates (HR) were recorded before and after induction of anesthesia. Significant changes 10 min following induction of anesthesia but before intubation included increases in SBP in the 5 micrograms/kg group (P less than 0.01) and in the ratio of preejection period to left ventricular ejection time in the 20 micrograms/kg group (P less than 0.05). Instances of myoclonic jerking and coughing episodes were observed in all three study groups. Following intubation there were significant (P less than 0.05) increases in SBP in all groups, in DBP in the 5 micrograms/kg group, and in HR in the 5 micrograms/kg and 10 micrograms/kg groups. Smaller increases in SBP, DBP, and HR were seen in all groups after skin incision and sternotomy. Mean plasma catecholamine levels showed nonsignificant increases following periods of intraoperative stimulation with wide patient variations. Recovery of responsiveness to command occurred in all groups within one hour from the end of surgery but extubation was impeded by shallow periodic breathing and hypercapnea. The authors conclude that for children undergoing open heart surgery use of sufentanil as a sole anesthetic in bolus form did not provide a reliable depth of anesthesia with any of the induction doses studied.

Anesthesia, Intravenous↗
PubMed1985

Somatosensory evoked potentials: monitoring cerebral functions following liver transplantation.

Serial somatosensory evoked potentials (SEPs) were obtained from a patient with Wilson's disease who had had liver transplantation. Correlating with recovery of hepatic encephalopathy and liver functions following the surgery, SEPs showed progressive normalization of peak latencies and waveforms. The data indicate that SEP may be a useful objective method in assessing recovery of cerebral functions following liver transplantation.

Adolescent↗
PubMed1985

Dose dependency of aflatoxin B1 binding on human high molecular weight DNA in the activation of proto-oncogene.

The binding of aflatoxin B1, AFB1, a potent hepatocarcinogen, to various high molecular weight (HMW) DNAs from human normal liver and two liver cancer cell lines, Alexander primary liver carcinoma (PLC) and Mahlavu hepatocellular carcinoma (hHC) and from NIH/3T3 cell have been investigated. The kinetics of AFB1 binding to these DNAs showed similar initial rates but the extents of binding to the PLC and hHC DNAs seemed to be slightly higher. Preferential AFB1 bindings were identified in both PLC and hHC DNAs compared to normal liver DNA when analyzed by restriction endonuclease digestions and agarose gel electrophoresis. A critical AFB1 binding dosage, ranging 100 to 460 fmole/microgram DNA, was found to activate the carcinogenic effect of the Mahlavu hHC HMW DNA, but not normal liver HMW DNA, rendering it capable of inducing focal transformation in NIH/3T3 cell. Excessive AFB1 binding on the hHC and PLC HMW DNAs resulted in an "over-kill" of both cell transformation capability and templating activity of the DNA.

Aflatoxin B1↗
PubMed1985

Lymphokine-induced cytotoxicity: requirement of two lymphokines for the induction of optimal cytotoxic response.

Lymphokines induce the generation of cytotoxic cells (LICC) in the absence of antigenic or mitogenic stimulation. In the present study, we have demonstrated that at least two lymphokines are involved. They are interleukin 2-conditioned medium (CM-IL 2), which was produced by W/Fu rat spleen cells cultured with concanavalin A-conjugated Sepharose beads, and cytotoxic cell differentiation factor-conditioned medium (CM-CCDF), which was produced primarily by the unstimulated mouse peritoneal macrophages. It was first established that CCDF synergized with IL 2 to induce the generation of LICC in normal spleen cells, and that this process was specifically blocked by the rat anti-IL 2 receptor monoclonal antibody. The maximal synergistic effect was obtained by using 10% CM-CCDF (v/v) and 0.1 to 0.3 U/ml of CM-IL 2. Higher doses of IL 2 (3 to 10 U/ml) reduced the cytotoxic response. The effectors of LICC were Thy-1+, Lyt-2- and AGM1-; therefore, they were neither classic CTL nor NK cells. The precursors were AGM1+, Lyt-2- cells that were consistent of being NK-like cells. When examining the temporal relationship between CCDF and IL 2, we found that 4 hr preincubation of the responders with IL 2 was sufficient to activate the cytotoxic precursor cells. CCDF was needed later for the differentiation of the activated precursors into cytotoxic effectors. In contrast, preincubation of the responders with CCDF, followed by additional incubation with IL 2, failed to induce any cytotoxic response. These results established that lymphokine-induced cytotoxicity can be separated into two phases. In the activation phase, IL 2 provides the first signal to activate the cytotoxic precursors, with the process being completed in 4 hr. In the differentiation phase, CCDF provides the second signal to induce the differentiation of the IL 2-activated precursors into cytotoxic effectors, with this process requiring 48 hr to complete. The sequential presence of these lymphokines at an appropriate time during the activation and differentiation phases is critical for the generation of LICC response.

Animals↗
PubMed1984

Cloning of the rat endogenous helper leukemia virus DNA sequence and expression of the helper activity encoded by the cloned DNA sequence in normal rat kidney cells by microinjection.

By the use of recombinant DNA technology and microinjection in cultured cells, the molecular genetic elements involved in the evolution of a retrovirus with the multipotential to infect, transform and replicate in host cell, have been critically examined in this investigation. Recently we have identified and purified the integrated and proviral DNA sequences specific for two rat endogenous helper leukemia viruses, WR- RaLV , originated from a chemically induced wild rat fibrosarcoma, and RHHV , isolated from a chemically induced rat hepatoma, HTC-H1 (1). By using a multidisciplinary approach combining restriction endonuclease analysis, reverse phase V-column chromatography, agarose gel electrophoresis, Southern blot transfer and filter nucleic acid hybridization, we were able to demonstrate that the rat helper leukemia viral DNA sequence was approximately 8.4-8.8 kb. The 8.8 kb RHHV DNA was molecularly cloned via the EK-1 certified vector pBR 322 plasmid into E. coli RRI cells. A successful recombinant clone, 8/32, that carried one entire RHHV 8.8 kb DNA sequence was mapped by restriction endonuclease analyses. Restricted DNA fragments of various sizes throughout the complete RHHV genome were isolated and purified for intranuclear microinjection into normal rat kidney cells. Release of type C infectious helper virus in these microinjected cells was investigated by superinfection on K-NRK, Kirsten sarcoma transformed non-producer cells. Recombination of the helper viral DNA sequence, en toto or of subgenomic sizes, carried in microinjected cells, with the sarcomagenic DNA sequence, carried in K-NRK cells, was also studied by genome-rescue and cell-transformation experiments. Our observations led to the conclusion that all critical genetic elements including the 5' LTR helper DNA sequence, gag, pol, and env genes, encoded for the biological activity of the type C helper virus resided within the 6.0 kb proximal to the 5' terminus of the endogenous rat type C helper virus DNA. They proved vitally essential for the recombination with the Src sequence during the evolution of an infectious, transforming and replication-competent retrovirus.

Animals↗
PubMed1984

Neuropathologic findings in thanatophoric dysplasia.

Neuropathologic study of eight cases of thanatophoric dysplasia (dwarfism) reveals developmental abnormalities including hypoplasia of posterior fossa, megalencephaly, cerebral gyral disorganization, hippocampal malformation, neuronal heterotopia, nuclear dysplasia, and abnormal axonal bundles. There are no noticeable differences in CNS abnormalities between thanatophoric dysplasia with and without cloverleaf skull (Kleeblattschädel). The CNS abnormalities, likely the result of abnormal neuronal migration and cytoarchitectonic disarrangement, are apparently not caused by skeletal abnormalities. The observation suggests that CNS abnormalities represent a characteristic and distinct manifestation of thanatophoric dysplasia.

Basal Ganglia↗
PubMed1984

Amniotic rupture, extra-amniotic pregnancy, and vernix granulomata.

is report describes two cases of amniotic rupture with delivery of live-born infants; one at 31 weeks and the other at term. The size of these amniotic sacs was apparently inadequate to contain the fetus, and extra-amniotic pregnancy was considered to have occurred. The ruptured and separated amniotic sacs were larger than previously reported examples and resembled those of delivery artifact. However, both placentas contained vernix granulomata in the separated amniotic mesenchyme and in the denuded mesenchyme of the chorionic plates, confirming the diagnosis of antepartum amniotic rupture. These observations add significant diagnostic criteria for identifying this entity in the absence of the hitherto commonly associated fetal amniotic band syndrome. Regardless of presence or absence of amniotic band syndrome, this entity is a sporadic condition, and recurrence is extremely rare in subsequent pregnancies.

Adult↗
PubMed1984

Induction of suppressor T cells by interleukin 2.

The optimal concentration of interleukin 2 (IL 2) for maintaining the in vitro growth of T cells was quite different from that required for the induction of cytotoxic T lymphocytes (CTL) in nu/nu spleen cells. Higher concentrations of IL 2-containing preparations (10 to 30% v/v or 5 to 15 U/ml) were needed to promote the T cell growth, whereas lower concentrations (1 to 3% v/v or 0.5 to 1.5 U/ml) were needed to generate alloreactive CTL. It was further shown that the addition of high concentrations of IL 2 (10 to 30%) suppressed the generation of alloreactive CTL in conventional MLC. High concentrations of IL 2 induced the generation of antigen-nonspecific suppressor T cells in normal spleen cell cultures and augmented the generation of antigen-specific suppressor T cells in MLC. These suppressor cells suppressed the generation of CTL in fresh MLC and in polyclonal CTL cultures. These suppressor T cells could be induced by rat (spleen)-produced, murine (EL-4 cells) produced IL 2 preparations, and a purified human recombinant IL 2 (HR-IL2). The ability to induce suppressor cells correlated with the activity of IL 2 present in these preparations and was independent of their ability to induce cytotoxic effectors. These findings indicate that IL 2 may play a dual role in the regulation of CTL responses. We suggest that during antigen sensitization, the initial endogenous production of lower levels of IL 2 provided the second signal for the differentiation and proliferation of CTL. When higher levels of IL 2 were produced later, the suppressor T cell precursors were activated and differentiated into suppressor effectors to regulate the CTL response.

Animals↗
PubMed1984

Metabolites of Bacillus sp. isolated from flax-suppressive soil.

A culture of Bacillus sp. was isolated from the suppressive flax soil. It could inhibit the growth of many plant pathogens that were found in suppressive flax soil, and an acidic ethyl acetate extract of culture broth of the isolated Bacillus showed significant inhibition of the growth of some plant pathogens. The antimicrobial activity of culture extracts (15 times concentrated) was higher than that of 400 micrograms/ml actidione or 200 micrograms/ml mycostatin (nystatin). The antimicrobial substances were relatively stable. After heating at 100 degrees C for 10 min. and 30 min., the activities were still 100% and 72%, respectively. Properties of the compounds were investigated by UV, TLC, GC and GCMS. The component with the retention time of 13.4 min in a gas chromatography was biologically active and the parent peak was at m/z 142.

Anti-Bacterial Agents↗
PubMed1983

Two lethal chondrodysplasias with giant chondrocytes.

Two infants, each with a different form of sporadic lethal chondrodysplasia, had multinucleated giant chondrocytes in resting cartilage. Both patients also had severe laryngeal stenosis and normal chromosomes. The radiographic abnormalities in one patient conformed to the recently delineated entity, atelosteogenesis (spondylohumerofemoral hypoplasia or giant cell chondrodysplasia); the other patient had an unclassified type of spondyloepiphyseal dysplasia. The findings in these two patients and the previously reported observations in spondylohumerofemoral dysplasia confirm that chondrocytic giant cells are a causally nonspecific phenomenon.

Cartilage↗
PubMed1983

Atheromatous embolization.

Atheromatous emboli occur spontaneously or may be secondary to surgery or trauma. Thurlbeck and Castleman found a 77% incidence of atheromatous emboli to the kidney following the surgical repair of abdominal aortic aneurysms. Atheromatous debris may be dislodged following aortography, renal arteriography, and left heart catheterization via the right femoral artery. External trauma, including hip fracture, external cardiac message, and blunt abdominal trauma have initiated peripheral atheromatous embolization. The incidence of this phenomenon may be higher than documented in the literature, since it is difficult to establish the diagnosis prior to death. Atheromatous emboli should be suspected clinically in elderly patients with sudden onset of pain and ischemia of the lower extremities or unexplained renal failure. At the present time, multiple atheromatous emboli may be treated symptomatically only. Muscle biopsy, retinal examination, and kidney biopsy may be used to differentiate atheromatous embolization from other clinical entities.

Accidents, Traffic↗