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Biomedical subjects

M Tan

Publications and source records attributed to M Tan.

At least 127 records · Page 7Linked to original sources
PubMed1997

Facial asymmetry in right- and left-handed men and women.

A posteroanterior cephalometric radiographic study was performed on the right- and left-handed men and women with normal occlusion. A posteroanterior cephalometric radiography was conducted in these subjects. Method of triangulation was used to measure various face areas. The surface areas of these triangles were compared with their equivalents on the contralateral side. Sex and its interactions with handedness and side were significant factors influencing facial areas. Areas on the left were found to be significantly larger than those on the right in right-handers. Left-handers were inconsistent in facial asymmetry, but they tended to have larger facial areas on the right than the left. Sex was especially significant for left-handers. It was suggested that an asymmetric development in some brain regions may be responsible for the development of asymmetric facial regions.

Adult↗
PubMed1997

The mixture distribution of left minus right hand skill in men and women.

The distribution of left minus right (L - R) hand skill (peg moving) was studied in 436 men and 247 women. In total sample, the distribution was continuous and a sum of two Gaussian curves. One of them was constituted by subjects with better right hand (79.0%) and better left hand (21.0%). The other curve (2.5% of total) was exclusively due to the subjects with better left hand. In men and women, the total curve was a sum of three overlapping Gaussian curves. Two of them were mostly due to the subjects with better right hand. There was a third curve representing almost entirely the subjects with better left hand. Women were more strongly right-handed than men. There was no significant sex difference at the sinistral side. The overall results were compatible with the right shift theory, but there was not a single Gaussian curve representing a chance distribution with a mean of zero. These results suggested that the distribution of manual asymmetry in skill is continuous, which may be described by probabilities due to subjects with better right and left hands; there is no place for chance in human handedness.

Adult↗
PubMed1997

[Distribution of 70kDa heat shock protein in rabbit brains after heat stress and heat stroke].

OBJECTIVE: Evaluation of the relationship between the induction of 70kDa heat shock protein in rabbit brains and heat stress. METHODS: HSP70 was detected using monoclonal antibody by ABC method in rabbit hypothalamus, hippocampus and cerberal cortex. RESULTS: Intense HSP70 staining was displayed in rabbit brains of the heat stroke group (rectal temperature 43 degrees C to death). Positive cells were distributed mainly in the CA1, CA2 regions of the hippocampus; granular cell layer I and pyramidal layer (II) of the cerebral cortex; and the periventricular area of hypothalamus. HSP70-psoitive substances were localized in the cytoplasm and neuronal processes, a few neurons exhibited dark staining nucle. Hosever, the rabbit brains of the general heat stress group (rectal temperature 42.0 degrees C, 30 minutes) had much weaker staining. CONCLUSION: Hyperthermia causes neuronal expression of HSP70, particularly under strong heat stress, and may be sustained till death.

Animals↗
PubMed1997

[Effects of lithium chloride and harringtonine on the differentiation, proliferation and c-myc proto-oncogene expression of HL-60 cells].

This research was to observe the effects of lithium chloride (LiCl) and Harringtonine (HT) on the proliferation and differentiation of HL-60 leukemia cells. The results obtained by liquid suspension culture, semi-solid colony culture and 3H-TdR incorporation into HL-60 cells indicated that different concentrations of LiCl (5-20 mmol/L) and HT (10(-8)-10(-5)mol/L) exerted the inhibitory effects in a dose-dependent manner on HL-60 cell proliferation respectively. When LiCl (10 mmol/L) and HT (10(-7) mol/L) were added together in the liquid culture or semi-solid culture of HL-60 cells, they showed much greater inhibitory effect than that by each agent separately. It was discovered that there was induction of the differentiation of HL-60 cells by lithium and HT and the induction of HL-60 cells differentiation by HT was markedly enhanced by the addition of low concentration of lithium. This work also showed that by treating HL-60 cells with lithium and HT, the expression of the c-myc proto-oncogene was markedly decreased as measured by RT/PCR-mRNA (P < 0.01). These findings provide some evidence of the mechanismcausing leukemic change and of the potential use of lithium and HT in the treatment of leukemia and in vitro purging of leukemic cells for autologous bone marrow transplantation.

Antineoplastic Agents↗
PubMed1997

[Mutation of p53 gene in the transformed fibroblasts detected by nonradioisotopic single strand conformation polymorphism analysis].

The human embryonic lung fibroblasts transformation was induced by chemical mutant Glycidyl Methacrylate (GMA) in vitro. Transformed clonies were isolated and then exon 5 and exon 8 of p53 gene were specifically amplified by polymerase chain reaction. Amplified fragments were detected by using silver stained single strand conformation polymorphism analysis. The results showed that exon 8 altered in the transformed cells, indicating that p53 gene played an important role in the human embryonic lung fibroblasts transformation induced by GMA.

Air Pollutants, Occupational↗
PubMed1997

[Transferrin subtyping of human semen, semen stain, vaginal fluid and mixed stain using isoelectric focusing and immunoblotting].

Transferrin (Tf) is an important genetic marker for personal identification in forensic science. We examined the subtypes in human semen, semen stain, vaginal fluid and mixed stain using isoelectric focusing and immunoblotting method(IEFIB). The results showed that, Tf subtypes of 8 semen and semen stain samples stored at room temperature for up to 32 weeks were the same as those in sera. Tf subtypes of 17 vaginal fluid and 4 mixed stain containing few semen were not detected. Tf Subtyping of 1 mixed stain containing enough semen was successful by using IEFIB. These results indicate that Tf is stable in semen stain. The Tf subtyping in semen stain and mixed stain containing enough semen can be carried out by using IEFIB method.

Exudates and Transudates↗
PubMed1997

Randomized controlled trial of trimebutine (anal sphincter relaxant) for pain after haemorrhoidectomy.

BACKGROUND: Anal sphincter spasm may aggravate pain after haemorrhoidectomy. The aims of this study were to investigate whether a trimebutine suppository (Proctolog) reduced anal resting pressure and, subsequently, to test its efficacy in relieving pain after haemorrhoidectomy. METHODS: Ten patients underwent anal manometry before and 4 h after Proctolog application. A controlled randomized trial was then conducted on 160 consecutive patients. A standard haemorrhoidectomy was performed. Eighty patients were then randomized to receive an application of Proctolog immediately after the procedure (group 1). The remaining 80 did not receive a suppository (controls, group 2). An independent, blinded observer determined the pain scores. RESULTS: Proctolog resulted in a mean 35 per cent reduction in resting anal pressure (P < 0.001). However, there were no differences in the pain score at 4 h after haemorrhoidectomy, maximum pain during the first 24 h, maximum pain during the second postoperative day, ketoprofen requirement or need for intramuscular pethidine injections between groups 1 and 2. CONCLUSION: Although Proctolog reduced mean resting anal pressure at 4 h after application, this did not affect pain after haemorrhoidectomy.

Female↗
PubMed1997

Biofeedback therapy for bowel dysfunction following low anterior resection.

Faecal incontinence and intractable constipation after low anterior resection (LAR) can be refractory to expectancy and appropriate anti-diarrhoeal or laxative medications. The efficacy of anorectal biofeedback therapy (BF) in this clinical situation was prospectively assessed. Eleven patients [5 men and 6 women; mean age 64.8 years; standard error of the mean (SEM) 3.3 years] had either faecal incontinence or intractable constipation which did not settle with medications, for at least 6 months [mean 33.3 (SEM 6.1) months] after LAR. They all underwent 4 sessions of outpatient BF. Assessment was by continence questionnaire and anorectal physiology tests, which were administered before and after BF. In 6 of 6 incontinent patients, weekly incontinent episodes were decreased [14.8 (SEM 2.1] before, 1.8 (SEM 0.8) after; P < 0.05) and anti-diarrhoeal drug requirements were reduced (needed in 6 before, 0 after; P < 0.05) after BF. In the 5 intractible constipation patients, the weekly stool frequency was improved [3 (SEM 0.5) before, 8.9 (SEM 1.6) after; P < 0.05] after BF. There were no significant changes in the anorectal physiology parameters after BF. At a mean follow-up of 12.9 (SEM 1.6) months, there were no regressions or complications. BF is a safe option for refractory bowel dysfunction following LAR.

Anal Canal↗
PubMed1997

Variants of chromosome 9 in phenotypically normal individuals.

The human chromosome 9 displays the highest degree of structural variability. Four different types of variants are described including pericentric inversion, extra G-positive band in the q arm, additional G-positive band in the p arm and duplication of band 9q21-q22. It is important to demonstrate inheritance from a phenotypically normal individual in order to differentiate between a variant chromosome and an abnormal chromosome.

Azure Stains↗
PubMed1997

Randomized controlled trial of open and closed haemorrhoidectomy.

BACKGROUND: This study was a prospective randomized comparison of healing following open and closed haemorrhoidectomy. METHODS: Sixty-seven consecutive patients (mean(s.e.m.) age 45(1.7) years; 35 men, 32 women) with three prolapsed piles were randomized to open haemorrhoidectomy (n = 34) or closed haemorrhoidectomy (n = 33). RESULTS: Mean(s.e.m.) follow-up was 8.7(0.2) months. There were no differences in the linear analogue pain scores, analgesic requirements and length of hospitalization after open haemorrhoidectomy and closed haemorrhoidectomy. Complete wound healing took significantly longer after closed haemorrhoidectomy (mean(s.e.m.) 6.9(0.7) weeks) compared with open haemorrhoidectomy (4.9(0.4)weeks) (P < 0.05). This was related to wound dehiscence in eight patients. Complication rates, however, were similar except for prolonged serous discharge from unhealed wounds. The anal manometry findings after both procedures were equivalent. CONCLUSION: Open haemorrhoidectomy leads to faster and more reliable wound healing, although this did not result in less pain or fewer complications.

Female↗
PubMed1996

Development and progression of renal disease in Pima Indians with non-insulin-dependent diabetes mellitus. Diabetic Renal Disease Study Group.

BACKGROUND: Non-insulin-dependent diabetes mellitus (NIDDM) is a major cause of end-stage renal disease. However, the course and determinants of renal failure in this type of diabetes have not been clearly defined. METHODS: We studied glomerular function at intervals of 6 to 12 months for 4 years in 194 Pima Indians selected to represent different stages in the development and progression of diabetic renal disease. Initially, 31 subjects had normal glucose tolerance, 29 had impaired glucose tolerance, 30 had newly diagnosed diabetes, and 104 had had diabetes for five years or more; of these 104, 20 had normal albumin excretion, 50 had microalbuminuria, and 34 had macroalbuminuria. The glomerular filtration rate, renal plasma flow, urinary albumin excretion, and blood pressure were measured at each examination. RESULTS: Initially, the mean (+/-SE) glomerular filtration rate was 143+/-7 ml per minute in subjects with newly diagnosed diabetes, 155+/-7 ml per minute in those with microalbuminuria, and 124+/-7 ml per minute in those with macroalbuminuria; these values were 16 percent, 26 percent, and 1 percent higher, respectively, than in the subjects with normal glucose tolerance (123+/-4 ml per minute). During four years of follow-up, the glomerular filtration rate increased by 18 percent in the subjects who initially had newly diagnosed diabetes (P=0.008); the rate declined by 3 percent in those with microalbuminuria at base line (P=0.29) and by 35 percent in those with macroalbuminuria (P<0.001). Higher base-line blood pressure predicted increasing urinary albumin excretion (P=0.006), and higher base-line urinary albumin excretion predicted a decline in the glomerular filtration rate (P<0.001). The initial glomerular filtration rate did not predict worsening albuminuria. CONCLUSIONS: The glomerular filtration rate is elevated at the onset of NIDDM and remains so while normal albumin excretion or microalbuminuria persists. It declines progressively after the development of macroalbuminuria.

Adolescent↗
PubMed1996

Continuous and group sequential conditional probability ratio tests for phase II clinical trials.

We present continuous and group sequential designs for phase II clinical trials based on the sequential conditional probability ratio test (SCPRT). The SCPRT is derived from a conditional likelihood ratio, where the conditioning is on what the corresponding (reference) fixed sample size test (RFSST) would achieve. In other words, we obtain the sequential design by controlling the maximum probability that the SCPRT does not agree with the RFSST. We shall discuss the difference between SCPRT and stochastic curtailment which also uses the concept of conditional distribution. We show that the power function of the SCPRT is virtually the same as that of the RFSST and its average sample numbers (ASNs) are close to those of Wald's sequential probability ratio test (SPRT), whereas its maximum sample size is no greater than that of the RFSST. Thus the SCPRT has all the desirable properties, such as allowing the use of the RFSST at the last analysis, of the Fleming procedure for phase II trials. The SCPRT, however, preserves the power function of the RFSST better and gives us the option for continuous monitoring. Our recommendation, therefore, is to use a group SCPRT boundary (for interim analyses performed as scheduled) embedded in a continuous SCPRT boundary (for unplanned interim analyses and analyses at times based on data trends). We provide as well a bias-adjusted estimator of the success rate after sequential stopping. We illustrate the method with several examples. The method applies to any single-arm clinical trial with binary endpoints, such as the classic paired design.

Clinical Trials, Phase II as Topic↗
PubMed1996

Overexpression of c-erbB-2/neu in breast cancer cells confers increased resistance to Taxol via mdr-1-independent mechanisms.

It has been reported that breast tumors that overexpress c-erbB-2/neu are less responsive to certain adjuvant chemotherapy regimens than those that express a normal amount of the gene product. To investigate whether overexpression of the c-erbB-2/neu-encoded p185 can indeed lead to increased chemoresistance in breast cancers, we introduced the human c-erbB-2/neu gene into the very low p185-expressing MDA-MB435 human breast cancer cells and examined Taxol sensitivities among the parental MDA-MB-435 cells and stable transfectants which express increased levels of p185. The p185-overexpressing MDA-MB-435 transfectants were more resistant to Taxol than the parental cells. The increased Taxol resistance was not accompanied by changes in doubling time and S-phase fraction. The increased Taxol resistance was independent from oncogenic transformation since it was observed only in c-erbB-2/neu-transformed cells and not ras-transformed cells when oncogene-transformed NIH3T3 cells were examined. To study whether p185 induced Taxol resistance through the mdr-1 pathway, we examined the mdr-l-encoded p170 levels in these transfectants. The MDA-MB-435 cells expressed very low levels of p170 and there was no increase of p170 expression in the p185-overexpressing MDA-MB-435 transfectants. Furthermore, these transfectants were not sensitized to Taxol treatment by mdr-1 blocker thioradazine. These data demonstrated that overexpression of c-erbB-2/neu can lead to intrinsic Taxol resistance independent from mdr-1 mechanisms.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Serial assessment of left ventricular chamber stiffness after acute myocardial infarction.

Left ventricular (LV) systolic function after acute myocardial infarction (AMI) has been the subject of detailed studies during the last decade, but diastolic phenomena during and after AMI are less well understood. Recently, it has been shown that early filling deceleration time accurately predicted LV chamber stiffness in an experimental model. To assess changes of LV stiffness after AMI, we studied 116 consecutive patients with 2-dimensional and Doppler echocardiographic examinations 1, 2, 3, 7, 21, and 42 days after AMI. Coronary angiography was performed in 101 patients. For the entire study group, deceleration time decreased nonsignificantly on day 2 and subsequently increased on days 3 (p = 0.001) and 7 (p = 0.036), returning toward initial values afterward. Deceleration time was shorter in large (peak creatine kinase level >1,000 U/L) versus small infarcts (p = 0.0008) and in patients with anterior versus inferior AMI (p = 0.02); there was no difference between patients with good and poor (< or = 45%) ejection fraction. These data indicate that increased LV stiffness can be detected 24 to 48 hours after AMI, but returns to normal within several days. Chamber stiffness is higher in large and anterior infarcts, but appears to be independent of LV systolic function.

Aged↗
PubMed1996

Prospective randomized controlled study of clinical function and anorectal physiology after low anterior resection: comparison of straight and colonic J pouch anastomoses.

Clinical function and anorectal physiology were studied prospectively in patients with rectal cancer after low anterior resection, randomized to either a straight anastomosis or an 8-cm colonic J pouch anastomosis. Sixteen patients (mean(s.e.m.) age 61.2(3.2) years; ten men, six women) had a straight anastomosis and 17 (mean(s.e.m.) age 61.2(3.8) years; six men, 11 women) a colonic pouch anastomosis. At 1 year after low anterior resection, a bowel function questionnaire was administered and anorectal physiology tests were performed. Patients with a straight anastomosis had significantly more frequent stools (median 6 (range 3-7) daily) compared with those who had a pouch (median 3 (range 2-7) daily; P = 0.02). A frequent sensation of incomplete defaecation was found in three patients with a straight anastomosis compared with ten who had a pouch anastomosis (P = 0.02). The mean resting anal pressures were lower after colonic pouch anastomosis (P = 0.049) but there were no differences in anal squeeze pressure, rectal sensation, volume of first sensation and compliance between the two groups. The decreased stool frequency with an 8-cm colonic pouch was not associated with measured improvements in rectal reservoir function. It is possible that reversed propulsive activity may be important in smaller colonic J pouches.

Adenocarcinoma↗
PubMed1996

Alterations of the p53, Rb and MDM2 genes in osteosarcoma.

Molecular defects affecting tumor-suppressor genes are an important step in the genesis of sarcomas. For example, inheritance of a defective Rb or p53 gene predisposes the carrier to develop osteosarcoma, among other malignancies. In this study, we have assessed the occurrence of p53, Rb and MDM2 alterations in the same samples of osteosarcomas, along with representative samples of various other sarcomas. Point mutations of the p53 gene were found in 13 of 42 osteosarcomas and 1 of 8 leiomyosarcomas, and gross rearrangement of the p53 gene was demonstrated in 5 of 37 osteosarcomas. The retinoblastoma susceptibility gene (Rb) was either rearranged or deleted in 7 of 37 osteosarcomas, 1 of 7 soft-tissue sarcomas and 1 of 4 Ewing sarcomas. Remarkably, 5 of the osteosarcomas having Rb alterations also had p53 mutations. Amplification and overexpression of the MDM2 oncogene may lead to increased MDM2-p53 binding resulting in inactivation of p53 function. A two- to threefold increase in the copy number of MDM2 was detected in 7 of 37 samples, 5 of which were osteosarcomas. Amplification of the MDM2 gene occurred independently of p53 mutation; one sample having threefold amplification of MDM2 also had a p53 mutation. In summary, 34 alterations of the p53, Rb and MDM2 genes were found in 26 of 42 (62%) osteosarcomas.

Base Sequence↗