Biomedical subjects

M Lin

Publications and source records attributed to M Lin.

At least 199 records · Page 11Linked to original sources

PubMed1998

Improved free musculocutaneous flap survival with induction of heat shock protein.

The cellular response to a wide variety of stresses results in the synthesis of a family of stress response proteins termed heat shock proteins. Recent studies have demonstrated that heat shock proteins produced in response to an initial stress seem to protect against subsequent unrelated stresses. Importantly, hyperthermia-induced heat shock proteins provided protection from ischemia/reperfusion injury in several organ transplantation models. We hypothesized that free musculocutaneous flap survival could be improved by enhancing the flap's tolerance to relative ischemia by the prior induction of heat shock proteins. Accordingly, we determined the heat shock protein response in skin and muscle after systemic or local heating and examined the effect on free musculocutaneous flap survival in a rat model. Free musculocutaneous flaps incorporating thigh adductor muscles and a 2 x 6-cm2 skin paddle were transplanted to the ipsilateral groin in three groups of male Wistar rats. Systemically heated rats (n = 6) were anesthetized and incubated for 30 minutes at 42 degrees C 6 hours before free musculocutaneous tissue transfer. Locally heated rats (n = 6) were anesthetized, and their donor site anterior thigh was placed for 30 minutes on a heating block set at 44 degrees C 6 hours before free tissue transfer. Control rats (n = 5) did not have heating pretreatment but underwent identical anesthesia. Animals were sacrificed on postoperative day 3, at which time skin loss (cm2) and muscle viability, quantified by nitroblue tetrazolium staining time, were assessed in a blinded fashion. The skin and muscle from the free flap were analyzed for HSP72 mRNA and protein using quantitative Northern and Western blot techniques. All free musculocutaneous flaps were viable. However, the locally and systemically heated rats demonstrated a marked improvement of skin survival, which correlated with increased skin levels of HSP72. There were no differences in nitroblue tetrazolium muscle staining times or muscle levels of HSP72 among the three groups. These findings suggest that prior heat-induced heat shock proteins result in improvement in musculocutaneous flap survival, which may have direct clinical applications, especially in high-risk patients.

Animals↗

PubMed1998

Fetal sheep adrenal blood flow responses to hypoxemia after splanchnicotomy using fluorescent microspheres.

Adrenal gland blood flow (ABF) increases during hypoxemia in fetal sheep, but regulation of ABF is poorly understood. The purpose of this study was to determine the effects of splanchnic nerve section on fetal ABF responses to hypoxemia using the fluorescent microsphere (FM) technique. At 125 days of gestation, 14 unanesthetized fetal sheep [bilateral splanchnicotomy (Splx, n = 6) and control (Cont, n = 8)] were injected with FM before and at 60 min of N2-induced hypoxemia (approximately 40% decrease in fetal arterial PO2). Adrenal tissue and reference blood samples were digested and filtered, and FM dye was extracted for spectrometer analysis. Baseline whole, medullary, and cortical ABF for the Cont group were similar to published values using radioactive microspheres and did not differ from Splx values. Hypoxemia increased whole, medullary, and cortical ABF (mean +/- SE) from baseline for the Cont group by 281 +/- 35, 258 +/- 31, and 496 +/- 81% (P < 0.05). The increase for the Splx group was attenuated compared with the Cont group (P < 0.05) for whole and medullary ABF (139 +/- 27 and 43 +/- 27%) but not cortical ABF (326 +/- 91%). We conclude that 1) the FM technique is valid for measuring fetal ABF and 2) in fetal sheep the splanchnic nerve is not necessary to maintain basal ABF but plays an important role in regulating the hypoxemia-induced increase in ABF through the medullary, but not cortical, ABF response.

Adrenal Glands↗

PubMed1998

Reference typing report for complement receptor 1 (CR1).

A total of 100 Chinese blood donors (50 from Shen-Zhen and 50 from Taiwan) were studied by the participants in addition to 9 reference samples. A new nomenclature for the CR1 structural alleles was recommended by the participants which would use a numbering system, e.g. CR1*1. The structural allele frequencies in the Chinese were: CR1*1 (190 kD) 0.96, CR1*2 (220 kD) 0.03, CR1*3 (160 kD) 0.01 and CR1*4 (250 kD) 0.00. The HindIII expression polymorphism was also studied and the high expressing allele had a gene frequency of 0.71 while the low expressor gene frequency was 0.28. Erythrocyte copy numbers were quantified and compared between laboratories with good correlation (R = 0.55-0.88). The mean (+/- SD) erythrocyte copy number was 463 (+/- 229) in the Taiwan donors and 446 (+/- 207) in the Mainland Chinese.

Alleles↗

PubMed1998

Peanut lectin-binding sites and mucins in benign and malignant colorectal tissues associated with schistomatosis.

An immunohistochemical and histochemical comparative study was carried out in benign and malignant colorectal tissues with and without schistosomiasis. This included a quantitative determination of peanut lectin (PNA)-binding sites and proliferating cell nuclear antigen (PCNA) expression and histochemical detection of mucin changes. 133 cases were studied, including 70 cases of colorectal carcinoma associated with schistosomiasis (CCS) and 63 cases of colorectal carcinoma without schistosomiasis (CC). Significant differences were found in the type of mucin-containing carcinomas (MC) between CCS and CC. 65% of non-tumorous mucosa adjacent to MC of the CCS group expressed PNA-binding sites, significantly higher than those of the MC in the CC group (31%). The non-tumorous mucosa in cases of MC of the CCS group also showed a high percentage of sialomucin-predominant secretion (69%, vs 38% in MC of the CC group). Consistently, the presence of PNA-binding sites in MC tumors of the CCS group was increased, compared with that in the same subtype in the CC group (respectively 65% and 31% of strong positivity for PNA). However, no differences in expression of PNA and mucin changes were demonstrated in the surrounding mucosa and tumorous tissues of non-mucin-containing carcinomas (NMC) between CCS and CC. The expression of PCNA was not different between CCS and CC and their subtypes. Our findings suggest a close relationship between mucin-containing colorectal carcinomas and schistosomiasis japonica.

Colorectal Neoplasms↗

PubMed1998

Isolation of proteins from subacrosomal region of spermatozoa from a marsupial, the tammar wallaby (Macropus eugenii).

Recent studies indicate that subacrosomal proteins are necessary for the attachment of the acrosome onto the nucleus during sperm formation, and for the stability of the nuclear membrane during fertilization. For the first time, subacrosomal proteins have been isolated from a marsupial species, the tammar wallaby (Macropus eugenii), using a method developed in our laboratory. Whole ejaculated spermatozoa were fractionated into head and tail sections by ultrasonication to extract subacrosomal proteins. The heads (> 95% purity) were then isolated from tail sections using centrifugation with a three-step discontinuous sucrose gradient (35, 68 and 75% (w/v). The heads were treated with 0.1% (v/v) Triton X-100 which stripped off the acrosome, but not the subacrosomal proteins, from the head. The proteins were finally extracted by 100 mmol NaOH l-1. Four prominent subacrosomal polypeptides, with molecular masses of 45, 38, 33 and 29 kDa, were recognized from the SDS-PAGE gel. The localization of these polypeptides (particularly the 45 kDa polypeptide) was confirmed by fluorescent and immunogold labelling with polyclonal antibodies raised in mice against the obtained polypeptides. In wallaby testes, the 45 kDa polypeptide was detected as early as at the step 3 spermatid and was mainly associated with the membrane of the newly formed acrosome vesicle. This polypeptide was also found on the acrosomal membrane of all older spermatids. The 45 kDa polypeptide was found on the acrosomal region of the spermatozoa collected from the caput, corpus and cauda of the epididymis. The similarity of the sperm anatomy of the tammar wallaby with that of other marsupials, such as the brushtail possum, implies that this procedure could be applied effectively to other marsupial species with minor modification.

Animals↗

PubMed1998

Expression of human interleukin 12 (hIL-12) in insect cells.

Human interleukin-12(hIL-12) is a herterodimer cytokine, which consists of two disulfide-linked subunits, p40 and p35. This paper reports the expression of hIL-12 using the Baculovirus Expression System in insect cells. First, we constructed two expression vectors pVL1392-hp40 and pVL1393-hp35, and then they were used to co-transfect the insect cells (Sf9) separately with linearized polyhedrosis virus genomic DNA. Two kinds of recombinant viruses AcNPV-hp40 and AcNPV-hp35 were visually screened out. Biological activity of the recombinant hIL-12 (rhIL-12) was detected in the conditioned medium using proliferation assay of PHA-activated human lymphocytes and the expression level was about 1.5 approximately 2 microg/10(6) cells. The results of real-time Biomolecular Interaction Analysis (BIA) and Northern blot demonstrated that the subunits of rhIL-12, hp35, and hp40 were expressed successfully in the insect cells. The apparent molecular weights of rhIL-12 and hp40 homodimer were 76 kDa and 92 kDa under non-reducing conditions of Western blot, respectively. The recombinant hp40 can significantly inhibit the biological activity of hIL-12.

Animals↗

PubMed1998

[Study on MDM2 and p53 gene proteins expression on acute leukemic cells and its correlation with chemotherapeutic efficacy].

OBJECTIVE: To explore MDM2 and p53 gene proteins expression on human acute leukemia (AL) cells and their predictive value for chemotherapeutic efficacy. METHODS: MDM2 and p53 gene proteins expression was assayed by immunohistochemical staining. RESULTS: 1. The expression rates of MDM2 and p53 gene proteins were 71.7% and 21.7% respectively in 46 AL patients. The rates were slightly higher in relapse/refractory AL than in previously untreated AL; there was no difference among AL subtypes. 2. MDM2+ and p53- accounted for 67.4%, while the uniform expression of MDM2 and p53 15.2% (P < 0.01). 3. The marrow complete remission (CR) rate (69.2%) of MDM2- patients was higher than that (33.3%) of MDM2+ patients (P < 0.05). 4. Two of 4 patients with MDM2+++ gained CR and then MDM2 turned negative. CONCLUSION: MDM2 gene protein was negatively related with p53 gene protein in AL cells. Different expression patterns of the two gene proteins could influence the therapeutic efficacy, and combined detection of the two may be used as a prognostic parameter for AL patients.

Adolescent↗

PubMed1998

[Research on the separation behavior of acidic drugs in capillary electrophoresis with reversed direction of electroosmotic flow].

The separation behavior of acidic drugs in capillary electrophoresis with reversal of electroosmotic flow was investigated systematically. Acetylsalicylic acid and its related compound salicylic acid were employed as objective drugs. The cationic surfactant cetyltrimethylammonium bromide (CTAB) was used as reversed reagent for electroosmotic flow. The experimental conditions, such as, cationic surfactant concentration, buffer pH and organic additives, which affected migration time, peak shape and column efficiency, were studied in detail. The experimental results indicated that high speed analysis could be achieved in the capillary electrophoresis with reversed electroosmotic flow induced by cationic surfactant when acidic drugs were analysed. The poor peak shape and low column efficiency caused by the interactions of CTAB with acidic anions would be improved by adding proper organic additive, such as, beta-cyclodextrin or acetonitrile.

Aspirin↗

PubMed1998

[The construction of Alcaligenes faecalis ntrC-lacZ fusion gene and its expression during association with rice roots].

A broad host range vector pLA2917 containing ntrC gene or ntrC-lacZ fusion were constructed, namely pLAC1 and pLAC2. The plasmids pLAC1 and pLAC2 were introduced into A. faecalis wild type strain A1501 by conjugation, subsequently to abtain A15C1 and A15C2. The expression and regulation of ntrC gene of A. faecalis associated with rice roots was investigated under the condition of the associative nitrogen fixation using X-Gal decoration method, micrograph and ntrC partially deletion mutant. The blue precipitation was strongly existed in parenchyma cells as well as in the lateral root primordial. It showed that ntrC gene could express at much higher level in these sites. In the presence of ammonia, the number of multi-copy ntrC conjugatants colonized on surface of rice roots is higher than that of wild type A1501, and the colonization of ntrC mutant is weakest among these three strains. This provided an evidence that ntrC gene might be involved in procedure of colonization of A. faecalis to rice roots.

Alcaligenes↗

PubMed1998

[Expression of bcl-2 gene in human trabecular cells induced by dexamethasone].

PURPOSE: To investigate the influence of dexamethasone on expression of bcl-2 gene in human trabecular cells. METHODS: The trabecular specimens from human eyes were cultured in vitro and the cultured cells of the third generation on slides were immersed in culture solution containing 10(-7) M dexamethasone for 6 hours, 12 hours and 24 hours respectively. The expression of bcl-2 gene was studied with LSAB. RESULTS: The positive cells of the bcl-2 protein could be identified after dexamethasone effected for 6 hours and the positive cell increased with time going on. CONCLUSION: The expression of bcl-2 gene can be induced by dexamethasone, it may be related with glaucomatic pathogenesis.

Apoptosis↗

PubMed1998

The study on culture and ultrastructure of glaucomatous trabecular cells in vitro.

PURPOSE: To establish the culture system of human glaucomatous trabecular cells in vitro and study their ultrastructures. METHODS: The trabecular specimens from trabeculectomy were cultured in vitro and passaged 3 times, then identified. Moreover, the glaucomatous cells were observed with electron microscope while compared with the normal ones. RESULTS: Cultured human glaucomatous trabecular cells were obtained. The ultrastructure of the cells showed the decrease in vilious project, coated vesicle and lysosomal inclusion. CONCLUSION: The establishment of human glaucomatous trabecular cells culture in vitro made the culture system more perfect. The morphologic changes might be related to the abnormal functions of human trabecular meshwork cells.

Cell Division↗

PubMed1998

[The study on the culture, freezing preservation and resuscitation of human trabecular cells in vitro].

PURPOSE: To establish the culture of human trabecular cells in vitro and study the freezing preservation and resuscitation. METHODS: The trabecular specimens from human eyes were cultured in vitro and passaged 3 times, then the cultured cells were frozen and preserved. The frozen cells were resuscitated after one week, two weeks, one month and two months. RESULTS: Cultured human trabecular cells were obtained. The frozen cells were resuscitated successfully. All of the resuscitated rates were more than 90%. CONCLUSION: The human trabecular cells were cultured in vitro successfully, they can also be frozen and resuscitated, which will be helpful to the establishment of cDNA library and the screening of associated glaucomatous genes.

Cell Division↗

PubMed1998

Distribution patterns of inflammatory sinonasal diseases.

BACKGROUND/AIM OF STUDY: There has been an increase in the demand for coronal sinus CT scan since the introduction of functional endoscopic sinus surgery; as the information provided by the scans assist the surgeon in the pre-operative plannings. Babbel and colleagues had demonstrated five distinctive patterns of recurring inflammatory sinonasal disease on CT scan. The aim of this study was to evaluate the patterns in the local population and to see if there was a difference compared to the Caucasian population. METHODS AND MATERIALS: A retrospective review of 302 scans done between March 1993 and September 1995 was carried out. All scans were carried out using a 5 mm thickness to cover the posterior sinuses and a 3 mm thickness to cover the anterior sinuses. The scans were then grouped into the various patterns and an analysis was carried out comparing the differences in the patterns between the Chinese and the non-Chinese, and between the local population and the Caucasian population in Babbel's series. RESULTS: There was no significant difference between the Chinese and the non-Chinese in the distribution of the various disease patterns. When compared to the Caucasian population, the local population had more sinonasal polyposis and sphenoethmoidal recess obstruction. CONCLUSION: The smaller nasal passages of the Asians, particularly in the Chinese, could be the reason for the more prevalence of Type III and Type IV disease compared to the Caucasian population. The more constant and frequent exposure to allergens might also contribute to the increased prevalence of Type IV disease.

Adolescent↗

PubMed1998

Reliability of the MOS SF36 health status measure in Australian general practice.

OBJECTIVE: Past studies suggest that the MOS SF36 holds promise as a useful instrument to assess health outcomes. Although it is being promoted for use in general practice, it is important first to examine its reliability in this setting. METHOD: A consecutive sample of 64 adult patients were recruited from an experienced general practitioner's waiting room in metropolitan Sydney. They were asked to complete identical questionnaires containing the Medical Outcomes Study (MOS) SF36 mailed to them on two separate occasions. RESULTS: There was a 66% response rate for both Time 1 and Time 2 surveys resulting in 64 paired questionnaires with high item completion rates (95-100%). The results demonstrated high internal consistency for both tests (Cronbach's a > 0.87). The reliability coefficients ranged from 0.59 to 0.89 across scales. CONCLUSIONS: This study provides support for the psychometric stability of the MOS SF36 as quality of life measure for patients in general practice. However, a large study is required to establish much needed normative ranges for self administered instruments in general practice.

Adolescent↗

PubMed1998

Analysis of cell death in myeloid cells inducibly expressing the cell cycle protein p55Cdc.

p55Cdc, a cell cycle protein is expressed in cycling mammalian cells and is required for normal cell division. Expression of this protein is regulated during the cell cycle, peaking in late G1 and S. We have previously shown that constitutive expression of p55Cdc results in inhibition of granulocyte differentiation. Degradation of p55Cdc is also required for apoptosis in growth factor and serum starved cells. In the present study we prepared stably transfected cells conditionally expressing p55Cdc in response to zinc stimulation to investigate the role of inducible p55Cdc expression in apoptosis of myeloid cells. We report that inducible expression of p55Cdc in the myeloid leukemic cell line 32Dc13 resulted in increased cell death. p55Cdc overexpression led to a statistically significant decrease in the viability of 32Dc13 cells compared with that of control cells. Furthermore, cell staining and flow cytometry analysis revealed that p55Cdc-overexpressing 32Dc13 cells progressed to apoptosis much earlier than uninduced cells. These results suggest that inducible expression of p55Cdc leads to earlier increases in cell death in the absence of growth factor and serum in myeloid leukemic cells.

Animals↗

PubMed1997

Response to second-line chemotherapy in patients with metastatic breast carcinoma previously responsive to first-line treatment: prognostic factors.

BACKGROUND: The aim of this retrospective study was to determine those prognostic factors associated with response to a second-line chemotherapy in patients with metastatic breast carcinoma (MBC) that was previously responsive to a first-line chemotherapy. METHODS: The 70 MBC patients studied had previously responded to a first-line chemotherapy, mainly anthracycline or anthracenedione-containing regimens. During first-line chemotherapy they had received treatment until the maximum response was obtained, at which time treatment was discontinued. Second-line chemotherapy regimens were of several types (48.5% with anthracycline). A study of prognostic factors associated with response to second-line chemotherapy was performed by univariate and multivariate analysis. RESULTS: Second-line chemotherapy achieved a 44% response rate, with a median response duration of 10 months. Survival was 13 months in the entire patient group, 22 months in responders, and 8 months in nonresponders. Univariate analysis identified seven factors related to patient response rate to second-line treatment. A better response rate to second-line chemotherapy was observed in patients with the following features: 1) chemotherapy free time (time between onset of metastatic disease and initiation of first-line) < 12 months (P = 0.03); 2) complete response to first-line chemotherapy (P = 0.013); 3) response duration to first-line chemotherapy > 14 months (P = 0.0001); 4) progression free interval (time between end of first-line treatment and initiation of second-line chemotherapy) > 11 months (P = 0.0001); 5) performance status at second-line treatment < 2 (P = 0.04); 6) tumor index at second-line chemotherapy < 4 (P = 0.05); and 7) treatment with an anthracycline-containing second-line regimen (P = 0.03). In multivariate analysis, only progression free interval was identified as being associated with response rate to second-line chemotherapy (P = 0.0001). CONCLUSIONS: Retained chemosensitivity appeared to be an important characteristic in patients responding to second-line chemotherapy.

Adult↗

PubMed1997

A novel, testis-specific mRNA transcript encoding an NH2-terminal truncated nitric-oxide synthase.

mRNA diversity represents a major theme of neuronal nitric-oxide synthase (nNOS) gene expression in somatic cells/tissues. Given that gonads often express unique and biologically informative variants of complex genes, we determined whether unique variants of nNOS are expressed in the testis. Analysis of cDNA clones isolated from human testis identified a novel, testis-specific nNOS (TnNOS) mRNA transcript. A predicted 3294-base pair open reading frame encodes an NH2-terminal truncated protein of 1098 amino acids. Measurement of calcium-activated L-[14C]citrulline formation and nitric oxide release in CHO-K1 cells stably transfected with the TnNOS cDNA indicates that this protein is a calcium-dependent nitric-oxide synthase with catalytic activity comparable to that of full-length nNOS. TnNOS transcripts exhibit novel 5' mRNA sequences encoded by two unique exons spliced to exon 4 of the full-length nNOS. Characterization of the genomic structure indicates that exonic regions used by the novel TnNOS are expressed from intron 3 of the NOS1 gene. Although lacking canonical TATA and CAAT boxes, the 5'-flanking region of the TnNOS exon 1 contains multiple putative cis-regulatory elements including those implicated in testis-specific gene expression. The downstream promoter of the human nNOS gene, which directs testis-specific expression of a novel NH2-terminal truncated nitric-oxide synthase, represents the first reported example in the NOS gene family of transcriptional diversity producing a variant NOS protein.

Alternative Splicing↗

PubMed1997

Linkage studies suggest a possible locus for bipolar disorder near the velo-cardio-facial syndrome region on chromosome 22.

Velo-cardio-facial syndrome (VCFS) is a congenital anomaly characterized by multiple dysmorphisms, cleft palate, cardiac anomalies, and learning disabilities, that results from a microdeletion of chromosome 22q11. An increased prevalence of psychiatric illness has been observed, with both schizophrenia and bipolar disorder commonly being diagnosed. For these reasons, the VCFS region is an interesting candidate region for bipolar disorder. We examined this region in 17 bipolar families from three populations: 13 families from the general North American population (University of California, San Diego/University of British Columbia, UCSD/UBC), three larger families from New York, and a portion of Old Order Amish pedigree 110. Three microsatellite markers spanning 13 cM around the VCFS region were genotyped in all the families. A maximum lod score of 2.51 was obtained in the UCSD/UBC families under a dominant model at D22S303. In the combined family set, maximum lod scores of 1.68 and 1.28 were obtained at this marker under dominant and recessive models, respectively. Four additional markers were subsequently typed in selected positive families, and yielded positive lods at 6 of 7 markers spanning 18 cM in this region. Nonparametric, multipoint analyses using the affected pedigree member (APM) method also yielded suggestive evidence for linkage in both the UCSD/UBC family set (P = 0.0024) and in the combined families (P = 0.017). Affected sibpair analyses were similarly positive in the UCSD/UBC families (P = 0.017), and in the combined families (P = 0.004). These results are suggestive of a possible locus for bipolar disorder near the VCFS region on chromosome 22.

Abnormalities, Multiple↗