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Biomedical subjects

G Li

Publications and source records attributed to G Li.

At least 937 records · Page 52Linked to original sources
PubMed1993

Field molecular epidemiology. Feasibility of monitoring for the malignant bladder cell phenotype in a benzidine-exposed occupational cohort.

Modern molecular and cellular biology have provided powerful new approaches to study cancer in the research laboratory, but these techniques have not been used extensively in field studies or in screening of high-risk occupational cohorts. The primary objective of this study was to demonstrate the use of cellular and molecular methods in combination with medical and epidemiologic methods to identify cancer cases, risk factors, and markers in a previously identified and defined cohort of Chinese workers exposed to benzidine. The screening of exposed workers included occupational, medical, and smoking histories to identify exogenous risk factors, a limited physical examination, Papanicolaou (PAP) urinary cytology, measurement of urine pH, quantitative fluorescence image analysis (QFIA) cytology to detect DNA hyperploidy, and quantitative fluorescence to detect expression of a low-grade bladder tumor-associated antigen (p300) by exfoliated urothelial cells and elevated expression of the neu oncogene product (p185). Detailed analysis of the accuracy of epidemiologic data and the adequacy of samples and accuracy of molecular techniques was carried out. Three groups were included in this study: group 1 included 23 bladder cancer cases who had previously been exposed to benzidine and served as two surrogates for late-emerging disease; group 2 consisted of 20 subjects with previous exposure history but not previously diagnosed with bladder cancer; and group 0 was the nonexposure and nonbladder cancer controls. The results showed that accurate questionnaire data and urine samples can be obtained at remote sites. Among the 20 group 2 subjects, two displayed abnormal findings by both QFIA cytology and p300 expression and were later confirmed to have bladder cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzidines↗
PubMed1993

Crashes of commuter aircraft and air taxis. What determines pilot survival?

Pilots have been recognized as an occupational group having very high work-related death rates. Commuter aircraft and air taxis are far more likely to be involved in fatal crashes than are larger airplanes. To examine the factors related to pilot survival in commuter aircraft and air taxi crashes, we analyzed National Transportation Safety Board data for the years 1983 to 1988. Case fatality rates were calculated for the pilots-in-command and odds ratios were estimated from a multivariate logistic regression model for variables related to pilots, aircraft, and circumstances. During the 6-year period, 536 people were killed and 744 injured in 888 commuter aircraft and air taxi crashes. The pilot case fatality rate was 20%. The most important determinants of pilot fatality were postcrash fire (odds ratio [OR] 8.2), off-airport location (OR 8.1), bad weather (OR 4.3), and nonuse of shoulder restraints (OR 3.7); all were significant at P < .01. Crash survival could be enhanced by more crashworthy fuel systems, aircraft seats, and use of restraint systems in commuter aircraft and air taxis. The value of shoulder restraints for pilots in these aircraft is confirmed and their use should be vigorously promoted.

Accidents, Aviation↗
PubMed1993

[The effect of acupuncture on plasticity of spinal Clarke's nucleus synaptic terminals].

Ten unilateral spared root cats with sectioned L1-S2 dorsal root ganglia, except L6, were used to explore the effect of acupuncture on plasticity of spinal Clarke's nucleus synaptic terminals. Five of the cats were needled on the operated hind limb for two courses (ten days as a course), and the other five were kept for control. Two pairs of acupoints located in the innervated area of L6 spinal nerve were used. The number of synaptic terminals per photo in neuropil of L3 Clarke's nucleus was compared directly, because there was no significant change in the area of Clarke's nucleus and its neuropil on the operated side of both groups. No significant difference was found in the number of three types of synaptic terminals between the unoperated sides of two groups, suggesting that acupuncture may not influence the contralateral side. In the control group, the number of giant axonal terminals from dorsal root of the operated side decreased to 75% of the unoperated side; however, in the experimental group, it recovered to contralateral or normal level of the operated side and was significantly higher than that of the control group's operated side, denoting that acupuncture may promote the plasticity such as collateral sprouting and synaptic reinnervation of coarse myelinated fibers from intact dorsal root, L6 mainly. The number of other two types of terminals from spinal interneurons showed no significant difference between the operated sides of two groups, indicating that acupuncture may not enhance the plasticity of nondorsal root nerve fibers.

Animals↗
PubMed1993

[Application of reverse transcription-polymerase chain reaction in rapid diagnosis and serotype identification of dengue virus infections].

RT-PCR was developed for the amplification of partial E genome fragment from four dengue serotypes. Of the six oligonucleotide primers designed one was shared by dengue virus type 1 and type 2, and one by type 3 and type 4. Each of the other four primers was type specific. Amplified products with 240, 150, 333 and 421 bp, respectively were identified by electrophoresis on 2% agarose gel and digestion with restriction enzyme Hind III. RT-PCR can detect dengue viral RNA from at least 5TCID50 virus, which was confirmed by detection of serial dilutions of culture supernatants. RT-PCR was also applied to serum samples from 60 acute patients. The findings showed that RT-PCR was of the same specificity as isolation of virus, followed by indirect fluorescent antibody tests. RT-PCR was more sensitive than cell culture and can be used for the rapid diagnosis and serotype identification of dengue virus infections.

Base Sequence↗
PubMed1993

[Production of transgenic rabbits by micro injection].

The feasibility of using whole animal instead of bioreactor in genetic engineering has been investigated with transgenic domestic rabbits. The gene chosen is the surface gene (S gene) of hepatitis B virus. Two plasmids were specifically constructed for this purpose, pHBV3.0 contains the promoter pre S gene and a part of c gene of the virus; while MT-SA, the S gene and mouse MT promotor. These plasmids were made linear by suitable restriction endonuclease before they were transferred into maleprounclei by means of microinjection. From 757 microinjected and transplanted fertilized eggs 101 rabbits were obtained. 57% of these animals were found with integrated microinjected genes. 28 of the transgenic animals were tested for the presence of the surface antigen of the virus in the serum by ELISA method. 8 animals were found positive, approximately 30% of the tested transgenic animals. The second generation transgenics were obtained either by first generation ransgenics crossed with non-trans-genics or transgenics. Among them 73% contained the transgene and 15% had the surface antigen in the serum. Some experiments were also carried out with human growth hormone gene.

Animals↗
PubMed1993

[A clinicopathological and immunohistochemical study of 49 cases of necrotizing lymphadenitis].

A clinicopathological and immunohistiochemical study of 49 cases of necrotizing lymphadenitis was made. Twenty-four patients were male and twenty-five female with the M:F ratio of 0.96:1. The patients ranged in age from 9 to 62 years with a mean of 26. Forty-nine patients had superficial lymphadenopathy, and twenty-two were accompanied by fever. The results also showed that there was multifoci necrosis present in the involved lymph nodes, particularly in the cortex or/and paracortex, with variable numbers of small lymphocytes, immunoblasts, histocytes and phagocytes, the latter with phagocytized nuclear debris derived from necrotizing T lymphocytes. However, granulocytes and plasmacytes were generally absent, and B lymphocytes rare. The pathogenesis of this disease remains unknown and the pathogen has not been found by Gram, Giemsa, PAS, Ziehl-Neelsen and Warthin-Starry stain. The diagnosis, differential diagnosis and etiology of this disease are discussed. We support the suggestion that this entity be called "Kikuchi-Fujimoto's disease" rather than "Histiocytic necrotizing lymphadenitis".

Adolescent↗
PubMed1993

Human factors in crashes of commuter airplanes.

Pilots and frequent travelers on commuter aircraft are exposed to higher risks of death or injury than those on major air carriers. To provide a better understanding of the circumstances of crashes of scheduled commuter airplanes, National Transportation Safety Board data were analyzed for all cases of death, serious injury, or major damage involving commuter airplanes during 1983-88, when 172 people were killed and 207 injured in 118 events. Three-fourths of cases involved inadequate pilot performance, notably poor handling of emergencies and improper instrument flying procedures. Pilot errors occurred disproportionately in bad weather, which played a role in 30% of crashes. Aircraft malfunctions were involved in 42% of crashes. Certain airplanes were overinvolved in gear-up landings or in crashes due to fuel mismanagement. Greater priority should be given to applying known preventive measures to the problem of commuter crashes.

Accidents, Aviation↗
PubMed1992

Human herpesvirus 7 is a T-lymphotropic virus and is related to, but significantly different from, human herpesvirus 6 and human cytomegalovirus.

An independent strain (JI) of human herpesvirus 7 (HHV-7) was isolated from a patient with chronic fatigue syndrome (CFS). No significant association could be established by seroepidemiology between HHV-7 and CFS. HHV-7 is a T-lymphotropic virus, infecting CD4+ and CD8+ primary lymphocytes. HHV-7 can also infect SUP-T1, an immature T-cell line, with variable success. Southern blot analysis with DNA probes scanning 58.8% of the human herpesvirus 6 (HHV-6) genome and hybridizing to all HHV-6 strains tested so far revealed homology to HHV-7 with only 37.4% of the total probe length. HHV-7 contains the GGGTTA repetitive sequence, as do HHV-6 and Marek's disease chicken herpesvirus. DNA sequencing of a 186-base-pair fragment of HHV-7(JI) revealed an identity with HHV-6 and human cytomegalovirus of 57.5% and 36%, respectively. Oligonucleotide primers derived from this sequence (HV7/HV8, HV10/HV11) amplified HHV-7 DNA only and did not amplify DNA from other human herpesviruses, including 12 different HHV-6 strains. Southern blot analysis with the p43L3 probe containing the 186-base-pair HHV-7 DNA fragment hybridized to HHV-7 DNA only. The molecular divergence between human cytomegalovirus, on the one hand, and HHV-6 and HHV-7, on the other, is greater than between HHV-6 and HHV-7, which, in turn, is greater than the difference between HHV-6 strains. This study supports the classification of HHV-7 as an additional member of the human beta-herpesviruses.

Amino Acid Sequence↗
PubMed1992

CENP-E is a putative kinetochore motor that accumulates just before mitosis.

The mechanics of chromosome movement, mitotic spindle assembly and spindle elongation have long been central questions of cell biology. After attachment in prometaphase of a microtubule from one pole, duplicated chromosome pairs travel towards the pole in a rapid but discontinuous motion. This is followed by a slower congression towards the midplate as the chromosome pair orients with each kinetochore attached to the microtubules from the nearest pole. The pairs disjoin at anaphase and translocate to opposite poles and the interpolar distance increases. Here we identify CENP-E as a kinesin-like motor protein (M(r) 312,000) that accumulates in the G2 phase of the cell cycle. CENP-E associates with kinetochores during congression, relocates to the spindle midzone at anaphase, and is quantitatively discarded at the end of the cell division. CENP-E is likely to be one of the motors responsible for mammalian chromosome movement and/or spindle elongation.

Amino Acid Sequence↗
PubMed1992

omega-Conotoxin-sensitive, voltage-operated Ca2+ channels in insulin-secreting cells.

The properties of voltage-operated Ca2+ channel subtypes were investigated in insulin-secreting RINm5F cells. Two types of channels were identified: a dihydropyridine-sensitive (L-type) channel, and an omega-conotoxin-sensitive (omega-type) channel. 125I-omega-Conotoxin bound with high affinity (Kd 46.7 pM) to a saturable number of binding sites (10.3 fmol/mg of protein). Toxin binding was not antagonized by L-type channel ligands, but was sensitive to Ca2+ and neomycin. 125I-omega-Conotoxin-labeled Ca2+ channels were recognized by autoantibodies of Lambert-Eaton myasthenic patients. These antibodies are known to be specific for the neuronal omega-type channel. High-voltage-activated Ca2+ currents, investigated with the patch-clamp technique, consisted of a major dihydropyridine-sensitive (L-type) component, and a minor fraction irreversibly blocked by omega-conotoxin. Depolarizing secretagogues, such as D-glyceraldehyde and alanine, induced Ca(2+)-dependent insulin secretion, which was attenuated by omega-conotoxin. Taken together, these results show that voltage-operated Ca2+ channels in insulin-secreting RINm5F cells are heterogeneous and, in particular, that an omega-type channel, pharmacologically, immunologically and electrophysiologically similar to the neuronal omega-type channel, is also expressed in endocrine cells where it might have a role in the control of hormone secretion.

Animals↗