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Biomedical subjects

Y Lin

Publications and source records attributed to Y Lin.

At least 523 records · Page 29Linked to original sources
PubMed1995

[Use of parenteral nutritional support in patients with gastric cancer: the relationship of protein turn over, immunocompetence and tumor cell kinetics].

In order to elucidate the effect of preoperative parenteral nutritional support (PNS) on protein metabolism, host immunocompetence and tumor cell kinetics, two prospective trials were made in patients with gastric cancer. All the patients were given PNS for 7 days in addition to oral intake. The positive nitrogen balance and increase of protein anabolic rate was greater in PNS groups than in control group. There was a moderate increase in NKC after PNS. The rise in CD4+ was significant (P < 0.05). The percentage of G0/G1 cells fell after PNS (P < 0.01), while that of the whole proliferative phase (S + G2 + M) rose (P < 0.05). These changes were not noted in normal gastric mucosa. In conclusion, despite of stimulating tumor cell proliferation, PNS helps to promote whole body protein synthesis and to amelio-rate the immunocompetence of advanced gastric cancer patients before operation.

Adult↗
PubMed1995

Protocol for collection and HPLC analysis of volatile carbonyl compounds in breath.

This noninvasive method for collection and analysis of a wide range of aldehydes and ketones in human breath may enable assessment of lipid peroxidation and metabolic status in vivo. Breath samples are drawn through silica cartridges impregnated with 2,4-dinitrophenylhydrazine, which traps carbonyls as their hydrazone derivatives. The hydrazone derivatives are eluted from the cartridges with acetonitrile, separated by reversed-phase HPLC, and quantified spectrophotometrically. Using this method, we have measured formaldehyde, acetaldehyde, acetone, propanal, 2-butanone, butanal, pentanal, and hexanal. Recoveries of carbonyls added to Douglas bags were > 90%, except for 2-butanone, which was 86.2%. The overall CVs for sampling plus analyzing duplicate aliquots of breath were < 11%. The results indicate that this protocol can be used to monitor changes of carbonyl production by analyzing expired air, which may, with further study, indicate physiological and pathological status.

Acetaldehyde↗
PubMed1995

[Studies on diagnostic bacteriophage of Vibrio fluvialis].

Species of Vibrio fluvialis are identified by their biochemical characteristics so far, with a lot of items to be determined, overelaborate procedure and expensiveness. Inaccordance with the fact that bacteriophage is a specific parasite inhabited in bacteria and has been used in identifying other bacteria with high specificity, some of Vibrio fluvialis bacteriophage isolated from natural environment were selected to make diagnostic preparation for Vibrio fluvialis identification. Diagnostic positivity of Vibrio fluvialis averaged 84.27%, and 87.84% for those of human source. Cross-lysis rates both for the same Vibrio genus and that of different families in the same genus were less then 3%, and no cross-lysis was found for the other enteric bacteria in different genera. There was no significant difference between diagnostic bacteriophage and biochemical tests for Vibrio of unknown species. This method was highly specific, sensitive, rapid, simple and inexpensive, and could be used in diagnosis of Vibrio fluvialis.

Bacteriophages↗
PubMed1995

Mutations of the tumour suppressor gene p53 in colorectal and hepatocellular carcinomas.

The present study describes mutations of the tumour suppressor gene p53 in a local collection of colorectal and hepatocellular carcinomas (HCCs). Tumour DNA was extracted from both fresh and paraffin-embedded tissues and exons 5-8 of the p53 gene were amplified by polymerase chain reaction (PCR). Mutations were detected by single-strand conformation polymorphism (SSCP) analysis followed by direct DNA sequencing. Of the 38 colorectal carcinomas and 42 HCCs examined, 15 (39%) and 13 (31%), respectively, showed p53 mutations. Two-thirds (10/15) of the mutations in colorectal carcinomas were base transitions with a predominance at CpG dinucleotide sites--a pattern characteristic to an endogenous process in cancer development. Three mutational hotspots at codons 175, 248 and 282 were also identified. Mutations did not correlate with histological grade, Dukes stage, or metastasis. However, tumours at the distal site of the colorectum showed a higher proportion of mutations than the proximal site. In the case of HCCs, majority (9/13) of the mutations were base transitions and no mutations were observed at codon 249. This is in contrast to results from other high-incidence areas such as Africa and China, where aflatoxin is believed to be a major aetiologic factor for liver cancers. The results therefore suggest that other risk factors, rather than dietary exposure to aflatoxin, may contribute to the high HCC incidence in Singapore.

Adenocarcinoma↗
PubMed1995

[Over expression of alpha-hANP in two kinds of expression systems of Escherichia coli].

Two kinds of expression plasmids carried Ref-Adaptor-(alpha-hANP) hybrid gene have been constructed. The adaptor GAA is the codon of glutamic acid which is a recognition site of the endoproteinase Glu-C. The expression of the heterologous fusion gene was controlled by the bacteriophage lambda PL promoter in the Escherichia coli expression system which is affected by the cIts857 repressor. These overproduced proteins were found in the form of inclusion bodies and constituted 35% and 48% of the total cellular protein respectively. The fusion protein was isolated and cleaved with Glu-C to liberate mature alpha-hANP, which demonstrated significant activities for reduction of blood pressure and vasorelaxation comparable to that of the chemically synthesized hormone. In this paper, the comparison between the two kinds of expression systems is also discussed.

Animals↗
PubMed1995

Morphologic observation of neutrophil diapedesis across bovine mammary gland epithelium in vitro.

Neutrophils are present in milk of cows as a means of suppressing invading pathogens during mastitis. However, the manner by which neutrophils traverse the secretory epithelia is still not clear: do they diapedese between epithelial cells or do they kill epithelial cells to gain entry into milk? We investigated the process of bovine neutrophil diapedesis across bovine mammary gland epithelium in vitro. The bovine mammary epithelial cell line MAC-T, grown on collagen-coated filters, formed a confluent monolayer with characteristic tight junctions, basal-apical polarity, and functional barriers to the dye trypan blue. Neutrophils added on the apical surface of the monolayer were stimulated to diapedese across the epithelium by the addition of Staphylococcus aureus (10(7) colony-forming units/ml) to the basal compartment. Light and transmission electron microscopy revealed the series of events for neutrophil transmigration: accumulation of neutrophils on the surface of epithelial monolayer; projection of pseudopods into intercellular junctions and movement of neutrophils between adjacent epithelial cells; and reapproximation of the lateral epithelial cell membranes and reformation of the apical tight junctions after neutrophils crossed the epithelium. Morphologically, epithelial cell damage caused by neutrophil diapedesis was not evident. This in vitro model provides a two-dimensional epithelial sheet by which neutrophil diapedesis can be qualitatively studied under defined conditions. Results of the study suggest a major mode by which bovine neutrophils diapedese across the alveolar epithelia into milk during mastitis.

Animals↗
PubMed1995

[High purification of human thrombin].

A highly purified human thrombin was prepared from plasma. The procedure involved the adsorption of prothrombin from human plasma by barium chloride and precipitation by using ammonium sulfate. The partially purified prothrombin was activated by tissue thromboplastin and followed by chromatography on Amberllte and SP-Sephadex. The purified enzyme is homogeneous on SDS-PAGE and has a specific activity toward fibrinogen of 2000 NIH U/mg. The recovery is about 30% approximately 40%. This highly purified human thrombin can be used as a tool enzyme in the downstream procedure of fused recombinant proteins expressed by genetic engineering.

Amino Acid Sequence↗
PubMed1995

[Study of autologous bone marrow transplantation in the treatment of gynecologic carcinoma].

OBJECTIVE: To investigate the role of autologous bone marrow transplantation (ABMT) in patients with gynecologic carcinoma treated by high-dose chemotherapy. METHODS: This was a presentation of four patients with ovarian carcinoma, two patients with primary fallopian tubal carcinoma, and 5/6 of them clinically staged as III and IV, treated with combination chemotherapy of cytoxan and carboplatin by intraperitoneal and intravenous infusion, the dose being 2.5-5 times those employed conventionaly. Autologous bone marrow collection and storage were conducted under strictly sterile conditions. Chemotherapy was given pre- and post-operatively and ABMT was performed immediately after chemotherapy. Careful follow-up was observed at monthly intervals. RESULTS: All of the six patients tolerated the treatment well, with no death within a median follow-up of 26 months (range 1532). Five of them lived more than 6 months with no evidence of disease. Two patients without gross residual tumor, who could not tolerate conventional chemotherapy which had to be discontinued, successfully received high-dose chemotherapy, supported by ABMT. All four patients with gross residual tumor benefited by immediate clinical remission after treatment. Median survival for all patients was 28 months (range 1253), median survival for stage IV patients was 24 months (range 1230). CONCLUSIONS: Patients subjected to high-dose chemotherapy supported by ABMT are exempted from suffering the cyclic multiple courses of chemotherapy, repeated or long-term hospitalization and may lead a life of good quality.

Adult↗
PubMed1995

[Vasoactive intestinal polypeptide prevents injury of pulmonary vascular permeability due to xanthine with xanthine oxidase].

Hyperpermeability is the crux of pathogenesis of sudden lung edema in many pulmonary disorders, especially in acute lung injury and acute respiratory distress syndrome (ARDS). Using our modified method for assessment of pulmonary vascular permeability, we observed the effects of xanthine with xanthine oxidase (X-XO) perfused in rat pulmonary artery and the protection of vasoactive intestinal polypeptide (VIP) against the injury of pulmonary vascular permeability. After addition of xanthine oxidase in the perfusate reservoir containing xanthine, 125I-albumin leak index (125I-ALI) was remarkably increased while peak airway pressure (Paw) showed no significant increase, and perfusion pressure of pulmonary artery (Ppa) and lung wet/dry weight ratio (W/D) were only slightly increased. Xanthine plus xanthine oxidase also increased thromboxane B2 (TX B2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) in the perfusate. Treatment with VIP obviously reduced or totally prevented all signs of injury. Simultaneously, VIP also diminished or abolished the associated generation of arachidonate products. The results indicated that VIP has potent protective activity against injury of pulmonary vascular permeability and may be a physiological modulator of inflammatory damage to vascular endothelium associated with toxic oxygen metabolites.

6-Ketoprostaglandin F1 alpha↗
PubMed1995

Vasoactive intestinal polypeptide prevents injury of pulmonary vascular permeability due to xanthine with xanthine oxidase.

Hyperpermeability is a crux of pathogenesis of sudden lung edema in many pulmonary disorders, especially in acute lung injury and adult respiratory distress syndrome (ARDS). Using our modified method for assessment of pulmonary vascular permeability, we observed the effects of xanthine with xanthine oxidase (X-XO) perfused in rat pulmonary artery and the protection of vasoactive intestinal polypeptide (VIP) against the injury of pulmonary vascular permeability. After addition of xanthine oxidase in the perfusate reservoir containing xanthine, 125I-albumin leak index (125IALI) was remarkably increased while peak airway pressure (Paw) was not significantly increased, and perfusion pressure of pulmonary artery (Ppa) and lung wet/dry weight ratio (W/D) were only slightly increased. Xanthine plus xanthine oxidase also increased thromboxane B2 (TX B2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) in the perfusate. Treatment with VIP obviously reduced or totally prevented all signs of injury. Simultaneously, VIP also diminished or abolished the associated generation of arachidonate products. The results indicated that VIP has potent protective activity against injury of pulmonary vascular permeability and may be a physiological modulator of inflammatory damage to vascular endothelium associated with toxic oxygen metabolites.

6-Ketoprostaglandin F1 alpha↗
PubMed1995

Effect of leflunomide and cyclosporine on the occurrence of chronic xenograft lesions.

Recently we and others have shown that a combination therapy of cyclosporine (CsA) together with anti-B lymphocyte immunosuppressants such as cyclophosphamide (CY) or leflunomide (LF) resulted in a complete suppression of xenoantibody formation and long-term heart graft survival in a hamster to rat xenograft model. Here we show that three months after transplantation, functioning xenografts may develop signs of chronic vascular and/or interstitial lesions depending on the immunosuppressants used. A combination maintenance therapy of CsA (10 mg/kg/day) together with LF (10 mg/kg/day, continuously) resulted in a healthy interstitium and normal blood vessels without signs of chronic rejection. When LF was stopped after one month of therapy but CsA continued for the whole observation period, only some local interstitial fibrosis was noticed. In contrast, when CsA was stopped after one month but LF continued, a pronounced infiltration with mononuclear cells was found, together with clear intima proliferation and severe fibrosis. In conclusion, long-term surviving xenografts may offer a new model to study the pathogenesis and therapeutic approach of chronic transplant lesions. In this model, a maintenance therapy of CsA and LF was able to prevent all signs of chronic rejection.

Animals↗
PubMed1995

Antibodies specific for the DNA quadruplex [d(CGC G4 GCG)4] isolated from autoimmune mice.

An autoantibody specific for a DNA quadruplex structure has been isolated and cloned from three-month-old autoimmune "viable motheaten" mice. This antibody (mev-alpha Q1) has been tested extensively in vitro and found to bind specifically and preferentially to the parallel-stranded quadruplex structure formed by the oligonucleotide d(CGC G4 GCG). The anti-quadruplex antibody does not show specific affinity for single-, double-, or triple-stranded oligonuclotides of similar CG-rich sequence motifs.

Animals↗
PubMed1995

[Ultrastructural changes in pulmonary microvascular damage in rats inflicted with burn, blast and combined burn-blast injury].

The pathological changes in pulmonary microvasculature in rats inflicted with overpressure blast, 15% third degree burns and combined burn-blast injury, respectively, were studied with electron microscopy and ultrastructural morphometry. Results indicated that the pathological changes in pulmonary microvasculature in 15% third degree burns were slight, and mainly restricted to ultrastructural level. While in severe blast and burn-blast injuries, the damage of pulmonary microvasculature including endothelial swelling and regeneration and dispersal of arteriole wall structure, was prominent. These changes form the basis of pulmonary hemorrhage and edema. Apart from vessel structural damages, arteriole constriction and capillary closure were also observed during 2 to 4 h postinjury. The vessel damage and dysfunction were more severe in combined injury than in blast injury alone. The mechanisms needed to be studied further.

Animals↗
PubMed1995

[An improved technique for preserving the nipple sensation in McKissock reduction mammaplasty].

An improved technique for preserving the nipple sensation in McKissock's reduction mammaplasty is described. Altogether four patients (seven breasts) have been operated on, and the primary results are highly satisfactory. The advantages of this technique are as followings: 1) The fourth lateral cutaneous nerve of the thorax, which mainly innervates the nipple, is preserved. All the patients retain the tactile sensation and the erectile reaction of the nipple after mammaplasty. 2) The operation is so modified that the suture line is smooth and has less tension. 3) The procedure ensures that both breasts are symmetrical after the operation.

Adult↗