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Biomedical subjects

Z Lin

Publications and source records attributed to Z Lin.

At least 253 records · Page 14Linked to original sources
PubMed1997

An autopsy case of suicidal strangulation with four looped rubber bands.

A rare case of suicidal strangulation with four looped rubber bands is reported. A 57-year-old female was found dead in the vestibule of her house, with four looped rubber bands wrapped around her neck. Her face was markedly congestive, and lots of petechial hemorrhages were seen on the face and in the palpebral conjunctive. At the medico-legal autopsy, the ligature mark was 1.7 cm in maximum width at the anterior part of the neck and accompanied by such vital reactions as linear hemorrhage, but there were no other injuries to account for her death. Many petechial hemorrhages were also found in the visceral pleurae and epicardium. There was hemocoagulum in the cardiac blood, and the other organs were as well markedly congestive. Gas-chromatographic analysis revealed ethanol; 0.83 mg/ml in the heart blood and 1.37 mg/ml in the urine. No other drugs or poisons were found with Toxi-Lab and REMEDi-HS systems. In addition, police investigation denied the possibility of homicide and disclosed her living will stating that she had suffered from a chronic heart disease. This case was of suicidal strangulation with looped rubber bands.

Asphyxia↗
PubMed1997

False identification of urinary ephedrine as methamphetamine by gas chromatography/mass spectrometry with a DB-17 column.

A 17-year-old motorcyclist was killed in a traffic accident. The urine sample collected at autopsy was screened by the Toxi-Lab system; it showed a possible presence of either methamphetamine (MA) or ephedrine (Eph). Gas chromatography-mass spectrometry (GC-MS) was carried out for a trifluoroacetyl (TFA)-derivatized sample after extraction with an Extrelut column. A peak was detected at the same retention time as that of the authentic Eph by GC-MS with a DB-17 wide-bore column; the mass spectrum of the peak was, however, very similar to that of MA. The presence of Eph and absence of MA were proved by GC-MS using a DB-1 column. The Eph in the urine was further confirmed by high performance liquid chromatography (HPLC)-MS using an ODS column. By the REMEDi HS system, Eph and methylephedrine were determined in the urine, and their concentrations (hydrochloride salt) were 0.752 and 2.13 micrograms/ml, respectively. Ethanol was detected as well in the blood (1.55 mg/ml) and urine (2.01 mg/ml) by a pulse heating method. Nicotine, caffeine and dihydrocodeine were also qualitatively detected in the urine by Toxi-Lab, HPLC-MS and REMEDi HS systems. The present case warned that urinary Eph can be misidentified as MA by GC-MS with an intermediately polar column after TFA derivatization.

Accidents, Traffic↗
PubMed1997

Gastric myoelectrical activity, gastric emptying and correlations with dyspepsia symptoms in patients with gastroesophageal reflux.

BACKGROUND: Delayed gastric emptying is a mechanism that contributes to the pathogenesis of gastroesophageal reflux. Electrogastrogram changes, gastric emptying rates, and Helicobacter pylori status were investigated, and a correlation was sought with dyspepsia symptoms in gastroesophageal reflux disease patients. METHODS: Fifty patients (27 females; mean age 43) with gastroesophageal reflux were studied. Electrogastrographic recordings were obtained 30 minutes before and simultaneously with a 2-hour radionuclide gastric-emptying test using an isotope-labeled solid meal. Symptoms of nausea, abdominal bloating, abdominal pain, and early satiety were graded from 0 to 5. RESULTS: Thirty-six percent of patients had delayed gastric eliminating. Thirty-eight percent (19/50) patients had abnormal electrogastrograms, and 11 of these 19 also had delayed gastric emptying. There was a significant difference in the electrogastrographic parameter of postprandial power change in patients with delayed versus normal gastric emptying (0.20 +/- 0.8 dB vs 3.17 +/- 0.8 dB, p < 0.05). In patients with an abnormal electrogastrogram, the mean symptom score was significantly higher than in patients with a normal electrogastrogram (2.18 +/- 0.26 vs 1.35 +/- 0.16, p < 0.05). Twenty-one percent (7/33) of patients were positive (+) for Helicobacter pylori overall, but this did not seem to affect electrogastrogram and gastric emptying findings. CONCLUSIONS: Fifty-two percent of gastroesophageal reflux disease patients have gastric motor or myoelectrical abnormalities that contribute to the pathogenesis of this entity and also help explain the high prevalence of dyspepsia in the clinical presentation of gastroesophageal reflux disease.

Adult↗
PubMed1997

Characterization of markers flanking the human SP-B locus.

We have previously identified a SP-B length polymorphism that appears with higher frequency in the RDS population (Biochem. J., 305, 1995, p583). This polymorphism encompasses a fairly large region, thus it is difficult to distinguish between variants with small size differences. Because of the importance of SP-B in normal lung function and the association of this SP-B polymorphism with RDS, we wished to identify and characterize polymorphic markers linked to the SP-B locus that would allow better resolution of SP-B alleles. In this report we a) characterized a novel (AAGG)n linked SP-B microsatellite marker; b) determined linkage of published markers with the SP-B locus and also determined the distance of each marker from the SP-B locus using medium and high resolution radiation hybrid panels; c) determined heterozygosity index and PIC values of the novel and known markers in various populations; and d) determined haplotypes using CEPH families. The availability of these SP-B linked markers/haplotypes will facilitate population and family based association studies. We are hopeful that the information gained will help to unravel the genetic complexity of RDS and respiratory diseases with regards to the SP-B locus.

Alleles↗
PubMed1997

[Effects of herpes simplex virus thymidine kinase gene transduction and prodrug on ovarian cancer cell].

OBJECTIVE: To evaluate the efficacy of gene therapy with the herpes simplex virus thymidine kinase (HSV-TK) gene transference followed by ganciclovir (GCV) therapy in ovarian cancer. METHODS: HSV-TK gene was inserted into the hind III site of pLNSX vector and recombinant plasmid (pLNS/HSV-TK) was constracted. Then, the recombinant plasmid was transfered into PA317 packaged cell and the producer cell line of recombinant retrovirus vector pLNS/HSV-TK was established. The cytotoxicity efficacy of HSV-TK/GCV system to AO cell line was evaluated by microcucture tetrajolium test (MTT) method. RESULTS: The recombinant retroviral vector pLNS/HSK-TK can transfer HSV-SK gene into the genome of AO cell line and make it sensitive to GCV. The growth inhibitory rate of AO cell line transfered by pLNS/HSV-TK was 98.0% in the medium containing 400 mumol GVC. CONCLUSION: The ovarian cancer cell line transfered by HSV-TK gene regressed rapidly in response to the GCV therapy.

Antiviral Agents↗
PubMed1997

[Preparation of leucine-methyl glutamate-glutamic acid copolymers].

The method for preparing leucine-methyl glutamate-glutamic acid copolymer was studied. In the first place benzyl glutamate and methyl glutamate were synthesized respectively. Then N-carboxy anhydrides (NCA) of leucine, benzyl glutamate or methyl glutamate were prepared in a closed container by phosgene-toluene solution method. After copolymerization the copolymers were debenzylated and demethylated by anhydrous hydrogen bromide. The free carboxyl group mole content in side chains of the copolymer was controlled by various standing periods following bubbling HBr. Analysis of infrared spectrogram and ultraviolet asorbance of copolymers indicated that this procedure resulted in the loss of almost all benzyl groups and some methyl groups.

Glutamic Acid↗
PubMed1996

Spontaneous Vesicle Formation in Aqueous Solutions of Linear Alkylbenzenesulfonate and a Linear Alkylbenzenesulfonate/Nonionic Surfactant Mixture upon Addition of Divalent Ions

Spontaneous vesicle formation is found in 1% aqueous solutions of linear alkylbenzenesulfonate (LAS) and mixtures of LAS and the nonionic surfactant, Cn-(N-methyl)glucose amide (MEGA), upon addition of a mixture of Ca2+/Mg2+ (2:1 molar ratio). Cryo-transmission electron microscopy (cryo-TEM) has been used to image the colloidal structures. A spherical micelle-to-vesicle transition occurs with increasing divalent ion concentration. However, thread-like micelles are absent from this transition. Many of the vesicles are exceptionally small, having a diameter less than 25 nm.

Journal Article↗
PubMed1996

Unexpected sudden death of a 12-year-old male with congenital single coronary artery.

A rare autopsy case of a 12-year-old male with a single coronary artery is reported in which he suddenly and unexpectedly died after a brief period of physical and mental excitation. The single coronary artery originated from the left aortic sinus, then branched out the left circumflex artery and afterwards descended as the left anterior descending artery, while the right coronary artery originated almost at a right angle from the left anterior descending artery. The entire heart as well as the cardiac conduction system depended exclusively on the single coronary artery for oxygenated blood supply, and the unbalanced blood distribution on his exertion probably led to sudden cardiac death. Moreover, in this case, both the deceased's mother (at the age of 20 years) and grandmother on the mother's side died suddenly, thus suggesting a possibility of maternal transmission of this congenital anomaly in his family.

Autopsy↗
PubMed1996

Multiplex genotype determination at a large number of gene loci.

To facilitate large-scale genotype analysis, an efficient PCR-based multiplex approach has been developed. For simultaneously amplifying the target sequences at a large number of genetic loci, locus-specific primers containing 5' universal tails are used. Attaching the universal tails to the target sequences in the initial PCR steps allows replacement of all specific primers with a pair of primers identical to the universal tails and converts the multiplex amplification into "uniplex." Simultaneous amplification of 26 genetic loci with this approach is described. The multiplex amplification can be coupled with genotype determination. By incorporating a single-base mismatch between a primer and the template into the target sequences, a polymorphic site can be converted into a desirable restriction fragment length polymorphism when it is necessary. In this way, the allelic PCR products for the polymorphic loci can be discriminated by gel electrophoresis after restriction enzyme digestion. In this study, 32 loci were typed in such a multiplex way.

Alleles↗
PubMed1996

Nucleotide binding-promoted conformational changes release a nonnative polypeptide from the Escherichia coli chaperonin GroEL.

The Escherichia coli chaperonins GroEL and GroES facilitate the refolding of polypeptide chains in an ATP hydrolysis-dependent reaction. The elementary steps in the binding and release of polypeptide substrates to GroEL were investigated in surface plasmon resonance studies to measure the rates of binding and dissociation of a normative variant of subtilisin. The rate constants determined for GroEL association with and dissociation from this variant yielded a micromolar dissociation constant, in agreement with independent calorimetric estimates. The rate of GroEL dissociation from the nonnative chain was increased significantly in the presence of 5'-adenylylimidodiphosphate (AMP-PNP), ADP, and ATP, yielding maximal values between 0.04 and 0.22 s(-1). The sigmoidal dependence of the dissociation rate on the concentration of AMP-PNP and ADP indicated that polypeptide dissociation is limited by a concerted conformational change that occurs after nucleotide binding. The dependence of the rate of release on ATP exhibited two sigmoidal transitions attributable to nucleotide binding to the distal and proximal toroid of a GroEL-polypeptide chain complex. The addition of GroES resulted in a marked increase in the rate of nonnative polypeptide release from GroEL, indicating that the cochaperonin binds more rapidly than the dissociation of polypeptides. These data demonstrate the importance of nucleotide binding-promoted concerted conformational changes for the release of chains from GroEL, which correlate with the sigmoidal hydrolysis of ATP by the chaperonin. The implications of these findings are discussed in terms of a working hypothesis for a single cycle of chaperonin action.

Adenine Nucleotides↗
PubMed1996

SCID mouse as a model for transplantation studies.

Mice expressing the severe combined immunodeficiency trait (SCID) lack functional T and B lymphocytes and have been widely used for the study of B- cell development and for cancer and HIV research. The purpose of this study was to evaluate the SCID mouse as a potential model for T-cell maturation and transplantation studies. C3H/HEN SCID mice screened by fluorescence-activated cell sorting (FACS) and radial immunodiffusion assay (RID) were verified homozygous recessive if CD3-, CD22-, and serum (IgG) <5 mg/liter. C3H/HEN SCID mice pretreated with 250 R total-body gamma irradiation were reconstituted with 2.5 to 4 x 10(7) donor bone marrow cells derived from [syngeneic (syn): male wild-type C3H/HEN, allogeneic (allo): male BALB/c or C57BL/6) mice by intravenous injection. Four weeks post-transplant, engraftment was determined by FACS; repopulation of blood, thymus, and spleen; RID; and histologic evaluation. Immune function against donor, recipient, and third-party antigen was assayed in vitro by mixed lymphocyte response (MLR) and in vivo by full-thickness skin grafting. Greater than 90% of both syngeneic and allogeneic reconstitutions expressed CD3+, CD4+, CD8+, and CD22+ cells of donor origin in peripheral blood and spleen. FACS analyses of lymphocyte subpopulations in blood and spleen were not significantly different between reconstituted SCID mice and wild-type C3H/HEN or BALB/c controls, with engraftment stable for >4 months. No evidence of graft-versus-host disease was observed in stable, long-term (>4 months postreconstitution) chimeras. White blood cell, total thymocyte, and total splenocyte counts were significantly elevated (P < 0.05: ANOVA, Student's t) following reconstitution of homozygous SCID mice to levels found in wild-type controls. Serum (IgG) for reconstituted allo- and syn-SCID mice was consistently > 150 mg/liter (n = 22), with histologic lymphocyte engraftment of spleen, duodenum, and thymus. Histologic examination of lymphocyte engraftment in spleen, duodenum, and thymus was indistinguishable from normal controls in SCID mice after reconstitution. Prior to reconstitution, scant lymphoid cells were observed at these sites. Allo-SCID splenocyte response against third-party antigen was significantly elevated (P < 0.01: ANOVA, Student's t) when compared with donor and recipient antigen response with a proliferation index (PI) comparable to wild-type controls. Unreconstituted SCID mice were unresponsive. In vivo, allo-SCID mice demonstrated rejection of only third-party skin grafts between postoperative days 9 and 14 (controls: postoperative days 7 and 11). The SCID mouse model demonstrates in vitro and in vivo B- and T-cell immune function comparable to that of wild-type mice and provides a useful model for T-cell maturation and transplantation studies.

Animals↗
PubMed1996

Abnormal gastric myoelectrical activity and delayed gastric emptying in patients with symptoms suggestive of gastroparesis.

Gastric myoelectrical activity modulates gastric motor activity. Abnormalities in gastric myoelectrical activity may be associated with gastric motility disorders. The aim of this study was to investigate the correlation of gastric myoelectrical activity with gastric emptying in symptomatic patients with and without gastroparesis. Ninety-seven patients with symptoms suggestive of gastroparesis participated in the study. Gastric myoelectrical activity was recorded using surface electrogastrography. The electrogastrogram (EGG) was recorded for 30 min in the fasting state and for 120 min after a solid test meal. Gastric emptying of the solid meal was simultaneously monitored for 120 min. Patients with delayed gastric emptying showed a significantly lower percentage of normal gastric slow waves (P < 0.03) and a significantly reduced increase of the dominant power in the postprandial EGG (P < 0.02). Postprandial EGG parameters were found to be able to predict delayed emptying of the stomach. Postprandial gastric dysrhythmia predicts delayed gastric emptying with an accuracy of 78%, while the abnormality in postprandial EGG power predicts delayed gastric emptying with an accuracy of 75%. All patients with abnormalities in both the rhythmicity and the power had delayed gastric emptying. Patients with delayed gastric emptying have a lower percentage of normal gastric slow waves in the EGG and a lower postprandial increase in the dominant power. Abnormalities in the postprandial EGG seem to be able to predict delayed emptying of the stomach. However, a normal EGG does not seem to guarantee normal emptying of the stomach.

Adolescent↗
PubMed1996

The molecular identity of Ca channel alpha 1-subunits expressed in rat sympathetic neurons.

Much of our understanding of the mechanisms of the gating, modulation, and function of neuronal Ca channels has its origins in investigations of sympathetic neurons. In this article, we use molecular analyses to identify the three Ca channel alpha 1-subunits that are the likely counterparts to the pharmacologically defined: omega-Conotoxin GVIA-sensitive N-type; dihydropyridine-sensitive L-type, and omega-Conotoxin GVIA-insensitive, dihydropyridine-insensitive Ca channel currents observed in sympathetic neurons. With a combination of degenerate and exact primers, small regions of Ca channel alpha 1-subunit sequences were amplified by the polymerase chain reaction (PCR). Although all five Ca channel alpha 1-subunit genes were expressed in rat sympathetic ganglia, alpha 1B-, alpha 1D-, and alpha 1E-derived cDNAs were the dominant species. No novel Ca channel alpha 1-sequences were identified in the regions selected for amplification, and we conclude that alpha 1B, alpha 1D, and alpha 1E likely encode, respectively, N-type, L-type, and non-N/non-L-type channel currents of rat sympathetic neurons. In addition, we show that Ca channel beta 2-, beta 3-, and beta 4-subunit sequences are strongly represented in sympathetic ganglia. The results of this study also suggest that alpha 1D, and not alpha 1C, regulates Ca influx through dihydropyridine-sensitive Ca channel currents.

Amino Acid Sequence↗