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Biomedical subjects

M Lai

Publications and source records attributed to M Lai.

At least 55 records · Page 3Linked to original sources
PubMed2000

Temporal expression of tumor necrosis factor-alpha and nitric oxide synthase 2 in rat small intestine after endotoxin.

Temporal changes in tumor necrosis factor-alpha (TNF-alpha) and nitric oxide synthase 2 (NOS 2) were evaluated in segments of duodenum, jejunum, and ileum removed from male Sprague-Dawley rats 30, 60, 120, 180, and 240 min after lipopolysaccharide (LPS), 5 mg/kg, intraperitoneally. Plasma was assayed for TNF-alpha and for nitrate/nitrite (NOx). Intestinal and plasma TNF-alpha were elevated by 60 min after LPS and were back to control levels by 180 min. For control rats, NOS 2 was detected in the ileum, but not in the duodenum or the jejunum. In rats treated with LPS, NOS 2 was detected in all areas of the intestine at 120 min and was greatest at 240 min. Plasma NOx was elevated at 120 min and continued to increase to 240 min. The time course of changes in intestinal TNF-alpha and NOS 2 were similar to those reported for other tissues and suggest that the early and late actions of the LPS on the intestine may involve both mediators.

Analysis of Variance↗
PubMed2000

Corticosteroid production by fetal rat hippocampal neurons.

11beta-hydroxylase and aldosterone synthase catalyse the final stages of corticosterone and aldosterone synthesis respectively. Previously, we established that they are expressed in the rat brain, particularly the cerebellum and the hippocampus. Primary cultures of fetal rat neurons were studied. RT-PCR and immunohistochemistry established that neurons express 11beta-hydroxylase and aldosterone synthase mRNAs and protein. After incubating the cells with 10microM DOC for 24 hours, medium was analysed for aldosterone and corticosterone. Median % conversion of DOC to corticosterone was 7.6% compared to 0.4% in controls. Median % conversion of DOC to aldosterone was 6.2% compared to 0.06% in controls. Corticosteroids mediate a number of functions of mammalian brain, including blood pressure homeostasis, salt appetite and neuronal excitability. Local production of these steroids could have significant effects on these processes.

Aldosterone↗
PubMed2000

An attempt of identifying MS-associated loci as a follow-up of a genomic linkage study in the Italian population.

Subsequent to a genomic linkage study on Sardinian and Continental Italian families, we considered the possibility that some of the tested microsatellite markers showed association to MS. Markers selected on the basis of the data obtained in the original set of 70 multiplex families were tested for MS association in an additional set of 154 simplex families. A limited set of markers were further tested on an additional set of 100 simplex families. The results indicate the presence of a putative MS gene in 19q13.13.

Alleles↗
PubMed2000

Stem cell collection using the dideco excel continuous flow blood cell separator: parameters for optimal stem cell collection timing.

This study evaluates stem cell collection procedures performed with the Dideco Excel blood cell separator, with particular attention given to yields and separator collection efficiencies. Patients' blood precounts and yield parameters related to the harvest capacity of the collection system were investigated. Fifty-five collection procedures were analyzed in 32 patients suffering from hematological malignancies and solid tumors and mobilized with chemotherapy plus G-CSF. The median blood volume processed in each procedure was 15.8 liters (12-19.750), with a blood flow rate of 70 ml/min. Patients had the following median blood precount value: NC 7.81x10(9)/L, CD34+ cells 49.08x10(3)/ml. Leukapheresis procedures gave the following yields: NC 14.95x10(9), MNC 10.83x10(9), CD34+ cells 4.37x10(6); yields/kg, NC 0.21x10(9)kg, MNC 0. 15x10(9)/kg CD34+ cells 4.26x10(6)/kg. Procedures show the following collection efficiencies: NC 10.79%, MNC 29.06%, CD34+ 42.33%, PLT 26.5%. The RBC (red blood cell) contamination of the product was (median value) 20.9 ml for each procedure, and for platelets 1.76x10(11) per procedure. The CD34+ cell precounts strongly correlated with the CD34+ yields/kg (r=0.82. p=0.000). Furthermore the NC and MNC precounts correlated with the CD34+ yields/kg but only the MNC precount correlation is notable (r=0.57, p=0.000). The logistic regression analysis shows that CD34+ (p=0.008) but not NC (po=0.14), MNC (p=0.09), or PLT (p=0.53) precounts significantly influenced the collection of a sufficient dose of CD34+ cells for transplantation (> or =2.5x10(6)/kg). Eleven of the thirty-two patients have been transplanted till now, and all had a prompt and lasting trilineage engraftment NC >1x10(9)/L on day 12 (10-17). Our data show that the collection system analyzed in this report is able to collect large amounts of progenitor cells, harvesting >2.5x10(6)/kg CD34+ cells with a single procedure in 68.8% of patients and assuring complete recovery after stem cell transplantation.

Adolescent↗
PubMed2000

[Methods for microdissection-PCR-silver stain technique in paraffin-embedded tissue sections].

OBJECTIVE: To use the microdissection-PCR-silver stain technique in the paraffin- embedded tissue sections and analyze the microsatellite instability in colorectal cancer. METHODS: By microdissection technique, the lymphocytes and mesenchymal cells, normal mucous epithelial cells, displasia, adenoma, and carcinoma cells were recovered from paraffin-embedded tissue sections. The cells were digested by protinase K; the cell lysates were used as PCR template and the PCR products were analysed by denatured polyacrylamide gel electrophoresis and silver stain. Four microsatellite loci, TGF-betaRII(A)(10), hMSH(2)(A)(26)-Bat-26, hMSH(3)(A)(8), hMSH(6)(C)(8), were analyzed. RESULTS: In all 28 specimens, hMSH(3)(A)(8) and hMSH(6)(C) 8) loci were amplified successfully. TGF-betaRII(A)10), Bat-26 had consistent amplification in 23/28, 22/28 specimens, respectively. And Bat-26 microsatellite instability was found in carcinoma cells in 5 specimens, and in adenoma cells in one of the 5 specimens. CONCLUSION: Microdissection-PCR silver stain technique can be used in paraffin-embedded tissue sections with satisfactory results. This method can be employed in analyzing microsatellite instability in colorectal carcinoma.

Colorectal Neoplasms↗
PubMed2000

[Multiple patterns of angle closure mechanisms in primary angle closure glaucoma in Chinese].

OBJECTIVE: The mechanism of primary angle closure glaucoma (PACG) in Chinese is studied to establish a new classification system based on the etiology and mechanism of angle closure. METHODS: The anterior chamber angle's configuration and the anatomic structures related to the angle in 126 cases with PACG were observed with ultrasound biomicroscope (UBM), and the mechanisms of angle closure were analyzed by diagnostic treatment. RESULTS: Based on the configuration of the angle and anatomic structures related to the angle as well as the mechanisms of angle closure, PACG could be divided into following subtypes: pure pupillary block angle closure glaucoma [PPB, 48 cases (38.1%)]; pure non-pupillary angle closure glaucoma [PNP, 9 cases (7.1%)]; multiple mechanism angle closure glaucoma [MM, 69 cases (54.8%)]. PPB manifested that the relative position of pupillary margin was located anteriorly, the peripheral iris bombé was due to the pupillary block, and the angle closure was not related to the location and shape of the peripheral iris and ciliary body. PNP showed that the relative position of pupil margin was located posteriorly, the angle closure was not caused by the pupillary block, but caused by anterior located ciliary body and/or thick and anterior located peripheral iris. MM pattern was caused by both pupillary block and non-pupilary block, and most of the cases manifested creeping angle closure. CONCLUSIONS: The angle closure mechanisms of PACG in Chinese are of multiple patterns. Based on the different mechanisms of angle closure in PACG, a new classification system should be established to improve the diagnosis and treatment of PACG.

Adult↗
PubMed2000

[Methylation status of p16 gene in colorectal carcinoma and normal colonic mucosa].

OBJECTIVE: To investigate the methylation status and its significance of 5' CpG island of p16 gene in colorectal carcinoma and normal colonic mucosa. METHODS: PCR-based methylation assay was applied to examine a total of 60 samples of colorectal carcinoma and paired 60 samples of the normal colonic mucosa for p16 gene methylation in Hpa II, Sac II, Sma I sites. RESULTS: Methylation was identified in 5' CpG island of p16 gene in both colorectal carcinoma and normal colonic mucosa, but no significant difference obtained between normal mucosa and carcinoma. The methylation status in 5' CpG island of p16 gene in colorectal carcinoma was not related to the tumor size, type, and metastases of the lymph nodes. Nevertheless, there was a significant difference between the methylation status of Hpa II, Sac II and Sma I sites. CONCLUSIONS: The methylation in 5' CpG island of p16 gene in colonic mucosa is different in various restriction enzyme sites, and the methylation process of p16 gene in both normal colonic mucosa and colorectal carcinomas is complicated. Anyhow, there is a tendency that the increase of methylation in p16 gene is age dependent.

Adenocarcinoma↗
PubMed1999

Expression of the activin axis and neuronal rescue effects of recombinant activin A following hypoxic-ischemic brain injury in the infant rat.

Neurotrophic factors are induced in the brain in response to injury and may restrict the extent of neuronal loss and facilitate recovery. We have previously reported a strong neuronal induction of activin betaA subunit mRNA expression after a hypoxic-ischemic (HI) injury in the rat brain. Here, we further extended our studies to examine a role for the activin inhibitory binding protein, follistatin after injury and also to determine the potential of activin as a neuronal rescue agent. Ribonuclease protection assay (RPA) was used to quantify the time course of the mRNA expression of activin betaA subunit and follistatin, following a 60-min HI brain injury. Activin betaA subunit mRNA level increased in the contralateral hemisphere 5 h after injury and returned to normal at 10 h post injury. In contrast, follistatin mRNA levels decreased in the same hemisphere at 5 and 10 h after injury. The effect of intracerebroventrically (i. c.v.) administered recombinant human activin A or its antagonist, inhibin A, on neuronal death after a 15-min HI brain injury was determined for a number of brain regions. One microgram activin A (n=23) reduced the neuronal loss in the hippocampal CA1/2 region, dorsolateral striatum but not in the parietal cortex. In contrast, 1 microg of inhibin A (n=18) did not have a significant effect on the extent of neuronal loss in any of the affected regions. This pattern of neuroprotection was consistent with the distribution of immunoreactivity for the activin receptor type II subunit. These results demonstrate that activin A, but not its functional antagonist inhibin A, can enhance the survival of injured hippocampal and striatal neurons. Since follistatin is thought to exert a neutralising effect on activin A activity, the down-regulation of follistatin expression post injury may be allowing activin A to become more accessible to neurons after injury. Overall, these results suggest a role of the activin axis in modulating the survival of specific populations of injured neurons.

Activins↗
PubMed1999

Induction of CD69 antigen on normal CD4+ and CD8+ lymphocyte subsets and its relationship with the phenotype of responding T-cells.

We evaluated phenotype and apoptotic status of normal CD4+CD69+ and CD8+CD69+ peripheral blood T-lymphocytes after short-term challenge with escalating concentrations of phytohemagglutinin (PHA). The frequency of CD69-coexpressing CD4+ and CD8+ T-cells and CD69 staining intensity increased following T-cell mitogenic stimulation; these changes were proportional to PHA concentration in culture medium. A considerable fraction of lymphocytes underwent blast transformation, displaying increased forward and side scatter signals. Interestingly enough, PHA-responsive T-cells exhibited a predominantly CD25negCD38negTCRalphabetapos phenotype; APO-1/Fas antigen (CD95) could be detected on a minority of activated CD69+ T-cells. A considerable proportion of CD69+ lymphocytes expressed intracellular perforin; in addition, an average 16+/-6% CD69+ T-lymphocytes were apoptotic after 4 h of stimulation, as evaluated by 7-amino-actinomycin-D staining and by annexin-V binding. CD69+ activated lymphocytes comprise phenotypically heterogeneous cell subpopulations potentially devoted to diverse immunological functions, i.e., proliferation, apoptosis, or cell cytotoxicity; moreover, our findings indicate that CD69 expression is proportional to the intensity of the activating stimulus and that the capacity to upregulate CD69 antigen following short-term mitogenic challenge may be restricted to unactivated CD38negCD25negTCRalphabetapos T-lymphocytes.

Annexin A5↗
PubMed1999

Correlation of magnetic resonance imaging parameters with clinical disability in multiple sclerosis: a preliminary study.

Magnetic resonance imaging (MRI) is frequently used to monitor new treatments in multiple sclerosis (MS), but its role is limited by the uncertain relationship between MRI parameters and clinical disability. A brain MRI study using nine MRI parameters was undertaken in 15 MS patients with a wide spectrum of disability to evaluate the relationship between each parameter and disability. A strong correlation was found between disability (measured using Kurtzke's EDSS) and total lesion load on both proton density (PD; r = 0.79) and T1 (r = 0.71) weighted sequences. There was also a strong correlation of disability with average lesion magnetisation transfer ratio (MTR; r = -0.74) and calculated T1 (r = 0.71) but not with calculated T2 or the average signal intensity of lesions on the conventional T1-weighted, PD-weighted and heavily T2-weighted images. Thus, four parameters which measured either the extent of lesions (PD lesion load) or their pathological severity (MTR, calculated T1, hypointense T1-lesion load) were correlated significantly with disability. While this suggests that such parameters will be useful in treatment trial monitoring, further multi-parameter MRI studies, of larger cohorts and using a wider range of techniques, are indicated.

Adult↗
PubMed1999

Ileal nitric oxide formation is altered in the young rat in response to endotoxin: effects of exposure to alcohol in utero.

This study was designed to test the hypothesis that the activity and expression of iNOS in the ileum will be altered in young rats exposed to alcohol in utero (FAE). The subjects, 26-29-day-old rats, were progeny of dams fed an alcohol diet during gestation and their pair-fed/control cohorts. We determined the effects of endotoxin administration on ileal iNOS enzymatic activity and on ileal iNOS immunoreactivity. The basal levels of the measured variables were not significantly different between the groups. In response to LPS, however, FAE animals responded with a greater increase in ileal iNOS activity and immunoreactivity. The findings indicate that ileal iNOS is augmented in response to immune signals, which may partly account for the altered gut functions associated with FAE.

Animals↗
PubMed1999

Linkage analysis of multiple sclerosis with candidate region markers in Sardinian and Continental Italian families.

Previous genome screens in multiple sclerosis have shown some evidence of linkage in scattered chromosomal regions. Although in no case the evidence of each single study was compelling and although in general the linkage 'peaks' of the different studies did not coincide, some regions can be considered likely candidates for the presence of MS risk genes because of the clustering of MLS scores and homology with eae loci. We performed a linkage analysis of markers in these regions and of intragenic markers of some individual candidate genes (HLA-DRB1, CTLA-4, IL9, APOE, BCL2, TNFR2). For the first time, Southern European populations were targeted, namely Continental Italians and Sardinians. A total of 69 multiplex families were typed for 67 markers by a semi-automatic fluorescence-based assay. Results were analysed for linkage by two non-parametric tests: GENEHUNTER and SimIBD. In general, the linkage scores obtained were low, confirming the conclusion that no gene is playing a major role in the disease. However, some markers, in 2p11, 3q21.1, 7p15.2 and 22q13.1 stood out as promising since they showed higher scores with one or the other test. This stimulates further association analysis of a large number of simplex families from the same populations.

Genetic Linkage↗
PubMed1999

Clinical findings and outcomes of intra-hemodialysis cardiopulmonary resuscitation.

Renal failure with severe uremia is still an important cause of mortality, despite effective renal replacement therapy. Cardiopulmonary arrest (CPA) is the most severe complication during hemodialysis (HD). To acquire more information about cardiopulmonary resuscitation (CPR) during HD, we retrospectively enrolled 24 patients (11 males and 13 females) who had CPR during HD in a medical center during a 3-year period. Their mean age was 66.8 +/- 16.8 years. The CPR rate of the patients from our outpatient department (0.02%) was significantly lower than that from general wards (0.11%), the intensive care unit (ICU, 0.16%), or the emergency room (ER, 0.38%). Eighteen patients (75%) were initially resuscitated successfully. Only 11 patients (45.8%) survived more than 24 h after CPR, and 2 patients (8.3%) survived more than 1 month, but none survived until discharge. The rates of surviving 24 h and surviving to discharge during HD were lower than those in the general wards, the ICU or the ER. Sepsis (33.3%) and cardiogenic shock (25%) were the two leading causes of death. For analyzing factors affecting the outcome of CPR, we divided the patients into 2 groups by survival time (<==24 vs. >24 h). Patients with heart disease or with prolonged CPR durations (>30 min) had shorter survival. No significant survival difference between the 2 groups was found due to factors of age, sex, diabetic nephropathy, pre-arrest morbidity scores, pre-arrest laboratory data, renal failure pattern, HD duration, the preceding HD time and ultrafiltrated volume.

Aged↗
PubMed1999

Revision total hip arthroplasty in patients with avascular necrosis.

This retrospective study compared the results of revision total hip arthroplasty (THA) in patients with avascular necrosis to patients with osteoarthritis. Twenty-two revision THAs (34 components) in 19 patients with avascular necrosis were compared with 35 revision THAs (55 components) in 31 patients with osteoarthritis. All of the procedures were performed by a single surgeon between 1981 and 1994, and all patients had a minimum of 2 years of follow-up. At the time of revision surgery, the average age was 54 years for the avascular necrosis patients and 67 years for the osteoarthritis patients (P=.002). Clinical and radiographic follow-up was performed for an average of 7 years (range: 2-12 years). Six (18%) components in the avascular necrosis group and nine (16%) components in the osteoarthritis group required re-revision for aseptic loosening an average of 7 years after the original revision (range: 2-11 years). Statistical analysis demonstrated no significant difference between the two groups in regard to the incidence of failure, time to failure, Harris Hip Score, and radiographic appearance. Contrary to expectations derived from the literature on primary THA, no difference was found between the outcome and survivorship of revision THA in patients with avascular necrosis and patients with osteoarthritis, despite a significant difference in age.

Adult↗
PubMed1999

Large volume leukapheresis for collecting hemopoietic progenitors: role of CD 34+ precount in predicting successful collection.

In this work we evaluated the efficacy of stem cell collection with Large Volume Procedures. (LVP), and analysed the importance of the CD34+ cell precount in promoting the collection of a sufficient number of CD34+ cells for transplantation, using the Univariate Logistic Regression analysis. Eighty-nine leukapheresis were performed in 49 patients with hematological malignancies and solid tumors, mobilized with chemotherapy plus Granulocyte Colony Stimulating Factor (G-CSF). For each procedure 15.8 liters of blood were processed. The median value of Nucleated Cells (NC) and CD34+ cells precount was respectively 8.29 x 10(9)/ml (range 1.13/45.4) and 43.08 x 103/ml (range 1.06/795.2). Results show the capability of LVP to collect large quantities of hemopoietic progenitors with a median CD34+ cell total yield of 215.02 x 10(6) (range 5.03/2210). The yields per patients' body weight were: CD34+ cells 3.23 x 10(6)/kg (range 0.081/41.58). The regression analysis between blood cell precounts and collection yields gave the following correlations: the CD34+ cell precount correlates with CD34+ yield (r = 0.78 p < 0.00) and with CD34+ cell yield/kg (r = 0.76 p < 0.00). The number of CD34+ cells processed correlated with the number of CD34+ cells collected/kg (r = 0.83 p < 0.000). To investigate the importance of CD 34+ cell precount in promoting CD34+ cell yields > or =2.5 x 10(6)/kg we performed a Univariate Logistic Regression analysis that showed in our patients a probability of collecting > or =2.5 x 10(6) CD34+/kg that rose from 0.6 to 0.95 for CD 34+ precounts that oscillated from 30 to 40 x 10(3) CD34+ cells/ml, respectively. The Univariate Logistic Regression gave a probability of collecting > or =2.5 x 10(6) CD34+ cells/kg that oscillated between 0.64/0.98 for values of CD34+ cells processed from 6 x 10(6)/kg to 8 x 10(6)/kg, p < 0.000. Sixty-three percent of patients reached the target dose of 2.5 x 10(6) CD34+ cells/kg with only one LVP. Until now 12 patients have been transplanted and all have had a prompt and complete lasting recovery. These results confirm the efficacy of LVP in harvesting hemopoietic progenitors and their ability in reconstituting hemopoiesis of transplanted patients, enabling the estimation of CD34+ precounts and CD34+ cells processed values, highly predictive for the collection of > or =2.5 x 10(6) CD34+ cells/kg. Furthermore, the Logistic Model suggests that the best strategy to plan a successful CD34+ cell collection procedure is to identify for each patient the amount of CD34+ cells/kg to be processed rather than the fixed processing of 3/5 blood volumes in all patients.

Adolescent↗