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Biomedical subjects

K Y Lin

Publications and source records attributed to K Y Lin.

At least 73 records · Page 4Linked to original sources
PubMed1993

Fetal tendon healing: development of an experimental model.

An experimental model was developed to study the process of fetal tendon healing. The flexor digitorum profundus tendons of the right hindlimb of 14 fetal lambs were partially lacerated at 100 days' gestation (term 145 days) and then studied macroscopically and histologically at several postinjury intervals (2, 4, 7, 14, 28, 42, and 56 days); two lambs were studied at each interval. A similar procedure was done in 14 adult sheep, who served as a control group. The fetal lambs showed no subcutaneous scarring, the digital sheath and tendon healed 2 weeks after injury, and a smooth, gliding surface was reconstituted. Collagen fibers were randomly arranged at 1 week but became organized along the tendon axis by 2 weeks. No adhesions, ruptures, or triggering was noted in the healing fetal tendons. Normal morphology was restored by 6 weeks. In the adult, dense subcutaneous scarring was noted, the digital sheath healed by 4 weeks and the tendon gap by 6 weeks, but a smooth gliding surface was not restored. Collagen fibers were randomly arranged at 2 weeks and became organized along the tendon axis by 4 weeks after injury. There were no dense adhesions or ruptures, but 25 percent of the tendons showed triggering.

Animals↗
PubMed1993

[A case of vivax malaria with thrombocytopenia suggesting immunological mechanisms].

Recently, it has been shown that the thrombocytopenia that complicates some malarial infections is caused by immune mechanisms. We report a case of malaria associated with thrombocytopenia and increased platelet-associated IgG (PAIgG). In this case, anti-malarial therapy reduced the level of PAIgG to normal levels in association with normalization of the platelet count. This case suggests the immunological mechanisms of thrombocytopenia in malaria.

Adult↗
PubMed1992

Probing structural factors stabilizing antisense oligonucleotide duplexes: NMR studies of a DNA.DNA duplex containing a formacetal linkage.

The duplex formed by annealing the formacetal backbone modified dodecamer d-(CGCGTTOCH2OTTGCGC) to its complementary strand, d(GCGCAAAACGCG) (duplex I), has been studied by NMR techniques and analyzed with reference to its unmodified counterpart (duplex II). Comparison of parameters such as 2D cross-peak intensities, coupling constants, and spectral patterns indicates that structural perturbations caused by the incorporation of the formacetal linkage are minimal and localized to the central T4.A4 block. Duplex I adopts a B-type helical conformation with regular Watson-Crick base pairing and normal minor groove width. The methylene group is accommodated along the phosphate backbone in a conformation similar to that of the PO2 group found in the B-form DNA family. The central T6-T7 base pairs of duplex I melt simultaneously with the duplex, indicating a cooperative transition to single strands. Although the formacetal linkage affects global melting, as evidenced by a 3 degree C reduction in Tm for duplex I with respect to duplex II, the present study indicates that this is not the result of localized premelting at the formacetal site of duplex I but rather reflects the subtle interplay of several structural and energy factors which need to be further explored.

Base Sequence↗
PubMed1992

Induction of HSP70 is associated with vincristine resistance in heat-shocked 9L rat brain tumour cells.

The most prominent cellular changes in heat-shock response are induction of HSPs synthesis and reorganisation of cytoskeleton. Vincristine was used as a tool to evaluate the integrity of microtubules in 9L rat brain tumour cells recovering from heat-shock treatment. Cells treated at 45 degrees C for 15 min and recovered under normal growing condition became resistant to vincristine-inflicted cytotoxicity and microtubule destruction. Among all HSPs, the level of HSP70 and the degree of vincristine resistance are best correlated. HSP70 and tubulin were found to be associated with each other as they were co-immunoprecipitated by either anti-HSP70 or anti-beta-tubulin monoclonal antibody. The current studies establish for the first time that HSP70 can complex with tubulin in cells and this association may stabilise the organisation of microtubules thus protect the heat-treated cells from vincristine damage. These findings are noteworthy in combining hyperthermia and chemotherapy in the management of malignant diseases.

Animals↗
PubMed1992

[Mannitol reduces plasma hydrogen peroxide free radical in patients undergoing coronary artery bypass graft surgery].

During the procedure of coronary artery bypass graft surgery (CABG), the release of free oxygen radicals as a result of ischemia and reperfusion which plants the seeds of post-operative low cardiac output and arrhythmias has grave consequence on the reestablishment of cardiac function. A variety of chemical agents such as mannitol, allopurinol, catalase (Q-10) and superoxide dismutase (SOD) has proved to be considerably effective to improve the myocardial necrosis following ischemia and reperfusion. In this study we chose mannitol (0.2 gm/kg) as the free oxygen radicals scavenger and utilized mass spectrophotometric method to detect the variation of concentration of [H2O2], a by-product of free oxygen radical, in an attempt to evaluate the efficacy of mannitol in this regard in patients undergoing CABG. Patients were divided into experimental group (n = 19) and control group (n = 20). In the experimental group the concentration of [H2O2] changed from 61 +/- 24 microM/L pre-operatively to 77 +/- 18 microM/L post-operatively as against 75 +/- 31 microM/L and 99 +/- 31 microM/L respectively in the control group. In comparison, only the change in experimental group was statistically significant (p less than 0.05). We confirmed that mannitol functions considerably as a free oxygen radical scavenger since it reduces the production of [H2O2] in patients undergoing CABG.

Aged↗
PubMed1991

Hybridization properties of deoxyoligonucleotides containing anthraquinone pseudonucleosides.

Achiral pseudonucleosides bearing an anthraquinone moiety have been incorporated into deoxyoligonucleotides in internal, 3' and 5' positions. The ability of these modified deoxyoligonucleotides to hybridize to complementary RNA and DNA was investigated using Tm measurements. The anthraquinone was shown to enhance binding to a complementary RNA when linked to the 3' and 5' end. Pseudonucleoside substitutions on the 3' end of an oligonucleotide are also shown to confer serum stability to the oligonucleotide.

Anthraquinones↗
PubMed1991

Induction of heat-shock response and alterations of protein phosphorylation by a novel topoisomerase II inhibitor, withangulatin A, in 9L rat brain tumor cells.

Withangulatin A is a newly identified in vitro topoisomerase II inhibitor isolated from the Chinese antitumor herb Physalis angulata. In vivo, it was found to be cytotoxic, capable of suppressing general protein synthesis and of inducing the synthesis of a small set of proteins including those generated by heat-shock treatment. The 70 kDa protein generated by withangulatin A was unequivocally identified as the heat-shock protein 70 (HSP70) since both proteins migrated to the same position on two-dimensional polyacrylamide gels, could be recognized by a monoclonal antibody to human HSP70, and exhibited identical peptide maps. The induction of protein synthesis by withangulatin A was regulated at the transcriptional level since it was aborted in cells pre-treated with actinomycin D. However, the initiation of this process did not require de novo protein synthesis since it was not affected by cycloheximide. Other cellular effect of withangulatin A was alterations of protein phosphorylation including an enhancement of phosphorylation of a 65 kDa protein which was also detected in the heat-shocked cells. Moreover, this process was observed within 7.5 min after the initial heat treatment which is much faster than the onset of HSP synthesis. Therefore, increased phosphorylation of the 65 kDa protein may represent one of the earliest signals generated by both heat-shock and withangluatin A and may be involved in the upstream regulation of heat-shock response in cells.

Animals↗
PubMed1991

Quaternary salts of 2-[(hydroxyimino)methyl]imidazole. 5. Structure-activity relationships for side-chain nitro-, sulfone-, amino-, and aminosulfonyl-substituted analogues for therapy against anticholinesterase intoxication.

Several quaternary imidazolium oxime derivatives incorporating side chains bearing nitro, sulfone, amino, and aminosulfonyl substituents were prepared and evaluated as treatment therapeutics for anti-AChE intoxication. In vivo test results in the mouse revealed that many of these compounds are highly effective in providing life-saving protection against the extremely toxic cholinesterase inhibitors soman and tabun. Several structure-activity relationships were noted that were characteristic of the side-chain substituent. In vivo test results for additional selected derivatives of some of the more therapeutically active compounds indicated that the quaternary heteroaryl nucleus is essential for activity whereas a nucleophilic moiety (i.e., oxime) is not. In support of previous suspicions, these results afforded additional evidence suggesting that reactivation is not the main mode of antidotal action by the imidazolium oximes. An alternative antidotal mechanism is postulated that is consistent with all data and that involves enzyme protection by the compounds.

Animals↗
PubMed1991

An experimental study on the effect of rigid fixation on the developing craniofacial skeleton.

Rigid fixation of the craniofacial skeleton has proven of great value in adult orthognathic and traumatic reconstructive surgical procedures. This technique has gained increased acceptance in the surgical treatment of infants and young children with congenital malformations, despite the fact that its effects on subsequent craniofacial growth are unknown. To examine this question, an experimental model using 25 young kittens was developed to compare rigid fixation with conventional wire fixation, with and without osteotomy. Our findings demonstrate a regional restriction of growth in the developing craniofacial skeleton when both wire and plate and screw fixation are utilized in concert with osteotomy. Further, a compensatory growth was observed in individual animals when plate fixation was utilized that was not seen in the wire-treated group. This suggests that there is a dynamic growth interaction between restriction and compensation in this setting.

Animals↗
PubMed1991

[Echocardiographic assessment of the effect of aging on the diastolic and systolic functions of the left ventricle].

The effects of aging on the diastolic and systolic functions of the left ventricle were studied by echocardiography as follows. (1). Maximum velocity of circumferential fiber lengthening (negative peak Vcf) and shortening (peak Vcf) was assessed by digital M-mode echocardiography in 20 healthy young subjects and 26 healthy elderly subjects. The mean value of negative peak Vcf (-cir/sec) was -3.87 +/- 0.85 in the 20's. -4.48 +/- 1.14 in the 30's, -3.71 +/- 1.21 in the 40's, -2.70 +/- 0.90 in the 60's, -2.57 +/- 0.64 in the 70's, -2.33 +/- 0.77 in the 80's and -2.57 +/- 0.65 in the 90's showing significant difference among young and elderly groups (p less than 0.05- p less than 0.005). The mean value of peak Vcf showed no significant difference among young and elderly groups except for the group in the 30's which showed significant (p less than 0.05) difference between other groups. (2). Indices of the left ventricular systolic and diastolic functions were calculated by standard M-mode echocardiographic technique in 227 healthy subjects from 5 to 94 years in age by dividing them into 3 young groups and 4 elderly groups. As for the left ventricular internal diameters a tendency of increase was observed in the end diastolic diameter of the left ventricle in accordance with ageing. Fractional shortening of the left ventricular diameter which ranged from 36.2% to 36.7% in the 3 young groups and 36.9 to 40.3% in the 4 elderly groups and cardiac output showed no age dependent decrease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Analysis of ras gene mutations in gastrointestinal cancers.

Point mutations of c-Ki-ras genes were analyzed in 33 samples of human gastrointestinal malignancy. DNA extracted from the frozen tissue was amplified by polymerase chain reaction (PCR) and analyzed by direct sequencing and slot-blot hybridization at codons 12, 13 and 61 of c-Ki-ras. In 7 cases out of 19 colorectal cancers, point mutations were found: 3 cases at codon 12, 1 at codon 13, 2 at codon 61 of c-Ki-ras and one case had double mutations at codon 12 and codon 13. In 11 cases of gastric cancer, 4 showed point mutations: 1 at codon 12 and 3 at codon 13 of c-Ki-ras. In 3 pancreatic carcinomas, 2 had point mutations: one at codon 12 and the other at codon 13 of c-Ki-ras. The results indicate that c-Ki-ras gene point mutations are involved in the tumorigenesis of the human gastrointestinal system.

Adult↗
PubMed1990

The effect of rigid fixation on the survival of onlay bone grafts: an experimental study.

Much attention has recently been focused on rigid fixation as a method of improving fracture healing. Whether such fixation, when applied to onlay grafting, improves graft take and volume is unknown. To examine this question, we compared survival of both endochondral and membranous grafts fixed rigidly and nonrigidly in areas of low motion (snout) and high motion (femur) in a rabbit model. Gross morphology, histologic analysis, and graft volume kinetics were evaluated. Findings demonstrate that in areas of high motion, the application of rigid fixation improves graft survival, whereas in a low-motion region, no differences in graft volume retention as a function of fixation were observed. Histologically, no differences with the method of fixation employed were seen, and similar revascularization patterns were noted. By kinetic analysis, rigid fixation appears to exert its most profound effect early in the postgraft period. Membranous bone grafts remain superior to endochondral grafts under all circumstances. From these studies, we conclude that rigid fixation is the method of choice in all circumstances where onlay bone grafts may be exposed to motion, shear, and torsional forces.

Analysis of Variance↗
PubMed1990

Eosinophilic gastroenteritis with eosinophilic ascites: report of a case.

Eosinophilic gastroenteritis is a relatively uncommon disease of unknown etiology. Eosinophilic ascites resulting from significant serosal involvement is the rarest clinical subtype. The case reported here is of a 30-year-old male presenting with abdominal pain, diarrhea, and ascites. His personal history included childhood asthma, allergic rhinitis, and recurrent urticaria. The clinical picture was characterized by peripheral eosinophilia and eosinophilic infiltrates of the stomach and small bowel. Computed tomogram (CT) of the abdomen showed generalized thickening of the gastric and small bowel wall. Paracentesis revealed exudative ascites rich in eosinophils. The patient experienced an impressive response to steroid therapy.

Adult↗
PubMed1989

[A clinical evaluation of injectable fluconazole in the treatment of deep mycosis associated with hematological malignancy].

The clinical efficacy and the safety of fluconazole as given at an intravenous dose of 100-400 mg daily were assessed in 7 patients with deep mycosis associated with hematological malignancy. Enrolled in the study were 1 patient with acute lymphatic leukemia, 1 with acute myelocytic leukemia, 2 with acute myelomonocytic leukemia, 2 with malignant lymphoma and 1 with myelodysplastic syndrome. Pathogens isolated from 4 patients were all Candida species including 2 Candida albicans, 1 Candida parapsilosis and 1 Candida krusei. Diagnoses of fungal infections of the patients were Candida pneumonia in 3 patients, candidemia in 1 and fungemia suggested in 3. Assessment of the clinical efficacy was made on 4 patients from whom pathogens were isolated. The global clinical improvement was good in 2 patients and fair in 1 with Candida pneumonia and good in 1 with candidemia. In the mycological assessment, pathogenic fungi were eradicated in 3 patients and decreased in 1 patient. No significant adverse reactions nor abnormality in clinical laboratory tests related with the dosing of fluconazole were observed in any of the patients.

Acute Disease↗