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Biomedical subjects

A Tan

Publications and source records attributed to A Tan.

At least 73 records · Page 4Linked to original sources
PubMed1997

The use of Bacillus diarrhoeal enterotoxin (BDE) detection using an ELISA technique in the confirmation of the aetiology of Bacillus-mediated diarrhoea.

A commercially available ELISA kit was used for the detection of Bacillus diarrhoeal enterotoxin (BDE) in a variety of foods and faeces. The ability of isolates of Bacillus spp., including Bacillus cereus, to produce BDE in Brain Heart Infusion broth containing 0.1% glucose was also checked by use of the kit. Results show that 29 out of 31 B. cereus isolates were enterotoxigenic. Foods positive for performed BDE were always contaminated with > 10(5) B. cereus cfu g-1, but not all foods contaminated with large numbers of B. cereus were positive for BDE. Bacillus sp., other than one isolate which closely resembled B. subtilis, were negative for BDE production. Criteria for the confirmation of Bacillus-mediated diarrhoea should now include reports of symptoms and incubation periods consistent with the diarrhoeal form of food-poisoning by Bacillus spp., together with the results of tests for enterotoxigenicity of the Bacillus isolate, and detection of BDE in either the food and/or faeces.

Bacillus↗
PubMed1997

Enterostomal complications: are emergently created enterostomas at greater risk?

It is not unusual for surgeons to have to construct a enterostoma during an emergency abdominal operation. The enterostomal complications, often overlooked, can be serious for the patient. There are many factors relating to stoma complications. The purpose of this paper is to determine whether the emergency status of an operation is an independent risk. Over a 19-year period from 1976 to 1995, there were 1758 enterostomas constructed at our institution. Fifty-nine per cent were for emergent situations, defined as any operation performed for peritonitis, obstructions, or massive hemorrhage. The data pertaining to complications was compiled by the enterostomal therapist and prospectively recorded into an institutional database. Complications were characterized as skin problems, parastomal problems (infection, separation), retraction, stenosis, necrosis, prolapse, and herniation. There were 624 (35%) patients with recorded complications. It was not uncommon for a patient to have more than one complication. There were 500 (55%) skin problems, 111 (12%) parastomal problems, 104 (11%) retractions, 33 (4%) stenoses, 112 (12%) necroses, 28 (3%) prolapses, and 19 (3%) enterostomas herniated. Overall, there were 1044 emergently created enterostomas, and we found that 356 (34%) patients had a complication. The most common indications for emergency laparotomies were abdominal gunshot wounds (40%), bowel obstruction (20%), bowel perforation other than by gunshot or stab wound (15%), and diverticulitis (8%). Among the nonemergently created enterostomas (714), there were 268 (37%) with complications (P = 0.015). Our findings suggest that emergently created enterostomas are not at greater risk for complications, except for the ileostomy. Although further analysis of this particular subset must be undertaken, the technical intricacies of an ileostomy, including preoperative marking of the site, might have an important role.

Abdominal Injuries↗
PubMed1997

Primary monosymptomatic nocturnal enuresis in Singapore--parental perspectives in an Asian community.

Primary monosymptomatic nocturnal enuresis (PMNE) is often not openly discussed in Asian societies. We report the parental view of PMNE in Singapore, its impact on patients and their families and the traditional beliefs and its influence on subsequent management. A screening questionnaire was used in evaluating 30 children enrolled in a clinical trial on the use of oral Desmopressin for the treatment of PMNE. Primary monosymptomatic nocturnal enuresis was familial in 56.7% of patients. Fifty per cent of them were previously unevaluated. Earlier remedial attempts included bedtime fluid restriction and voiding (100%), incentive measures (43.3%), traditional practices (26.7%), punishment (20%), drugs (16.7%), psychotherapy (100%) and bladder training (3.3%). Perceived causes of PMNE were maturational delay (50%), deep sleep (50%), familial (43.3%), behavioural problems (43.3%) and excessive fluid intake (26.7%). Reasons for seeking treatment included restricted outdoor activities (90%), parental fatigue (86.7%), disrupted sleep for the household (46.7%) and fear of underlying pathology (26.7%). Perceived adverse effects on patients included social stigma (83.3%), disrupted sleep (33.3%) and impaired school performance (13.3%). Primary monosymptomatic nocturnal enuresis can thus be a chronic distressing problem in Asian communities.

Adolescent↗
PubMed1997

A technique for quantitation of protein deposits on rigid gas permeable contact lenses.

PURPOSE: The purpose of this study was to develop a method for quantitating protein on rigid gas permeable (RGP) lenses and apply it to worn lenses. METHODS: We built a video microscope and wrote software to measure light absorbance by contact lenses before and after protein staining with Coomassie brilliant blue. We corrected for the temporal stability and spatial uniformity of the system, and set the iris aperture so that both lens surfaces could be simultaneously focused. We examined four RGP lens types worn by 22 patients. Standard curves were prepared with plastic discs spiked with dialyzed Coomassie blue-stained bovine serum albumin. RESULTS: The method was linear (R2 = 0.99) from 14 to over 100 microg protein per image and independent of dioptric power from -6 to +14 diopters. Protein quantities on worn Equalens II, Advent, Quantum II, and Fluoroperm 92 lenses were not significantly different (123 +/- 36, 111 +/- 28, 110 +/- 23, and 83 +/- 15 microg/lens; means +/- SEMs, P > 0.7). Patients differed (P < 0.05) in protein deposition, independently of lens type, and fit a Poisson distribution. DISCUSSION: The method is adequate for quantitating protein on RGP lenses or for examining the efficacy of cleaning regimens or care systems. However, because of the non-Gaussian distribution of patient protein deposits, paired or cross-over experimental design and testing is recommended for studying protein deposition in clinical trials.

Animals↗
PubMed1997

Pharmacokinetic, hemodynamic, and metabolic effects of cyclosporine sandimmune versus the microemulsion neoral in heart transplant recipients.

BACKGROUND: Cyclosporine is a potent immunosuppressive agent that is, however, associated with systemic hypertension and renal dysfunction. The purpose of this investigation was to study the pharmacokinetic and long-term renal and hypertensive effects of Sandimmune (Sandoz) versus the new Neoral (Novartis) formulation of cyclosporine in heart transplant recipients. METHODS: Twenty heart transplant recipients with stable conditions and aged 54 +/- 9 years were studied in an open-labeled single-arm conversion protocol. Twelve-hour pharmacokinetic studies were performed on Sandimmune and after 4 weeks of treatment with Neoral at similar dosage. The 24-hour blood pressure monitoring, creatinine clearance, and complete biochemistry profile were studied simultaneously to the pharmacokinetic studies. Six-month follow-up with serial measurements of cyclosporine levels, and biochemistry profile was completed. RESULTS: Conversion to Neoral resulted in a 24% increase in area-under-the-curve in spite of no significant changes in cyclosporine trough levels (165 +/- 48 [Sandimmune] vs 169 +/- 32 nmol/L; p = 0.26). Respectively, 16%, 68%, and 16% were poor, average, and good absorbers on Sandimmune versus 26% and 74% being average or good absorbers on Neoral. Averaged systolic and diastolic blood pressure were not affected by Neoral, but blood pressure readings increased in 20% of patients previously known as having hypertension. The 24-hour blood pressure data yielded no significant changes with Neoral, but the nocturnal drop in systolic blood pressure was attenuated by Neoral. Twenty-four-hour creatinine clearance was not affected by Neoral, but serum magnesium levels decreased significantly at 6 months. CONCLUSIONS: Neoral resulted in 24% increase in cyclosporine exposure without significant changes in trough levels, and improved absorption status. This greater drug exposure is well tolerated and resulted in a slight increase in blood pressure in a subset of patients and some decrease in magnesium levels, but it had no effect on renal function.

Adult↗
PubMed1996

Effects of prolonged sequential balloon inflations on results of coronary angioplasty.

In percutaneous transluminal coronary angioplasty (PTCA), prolonged balloon inflations using perfusion balloon catheters have shown a higher procedural success rate and fewer in-hospital complications than short balloon inflations. However, perfusion balloons have well-recognized limits for routine use. This study assessed the effects of a prolonged cumulative occlusion time obtained with sequential balloon inflations using a routine balloon catheter, applicable to all lesions, and compared these results with those obtained with standard short balloon inflations. Three hundred ten lesions (in 289 patients) were randomized to either standard (3 to 5 inflations < or = 1 minute each; n = 161) or prolonged (3 to 5 inflations of 3 to 5 minutes each; n = 149) balloon inflations. Angiographic success (residual stenosis <50% and no dissection > or = D1) was assessed at the end of this "protocol" phase. Further dilatation was performed if required ("adjunctive" phase). Systematic repeat catheterization was scheduled 4 to 6 months later. Cumulative inflation time was 198 +/- 58 seconds in the "standard" group versus 782 +/- 303 seconds in the "prolonged" group. At the end of the protocol phase, the success rate was higher after prolonged than after standard dilatation (92% vs 80%; p <0.002), with less frequent dissections (14% vs 30%; p = 0.0009). At the end of the adjunctive phase, required for 12 patients in the prolonged group and 32 patients in the standard group (p = 0.003), results were comparable in the 2 groups and the restenosis rate was similar at 6 months. The prolonged cumulative occlusion time achieved with sequential balloon inflations using a routine balloon catheter improves the immediate results of PTCA. Repeat catheterization shows no effect of prolonged sequential inflations on the restenosis rate.

Aged↗
PubMed1996

Rapid eye movement sleep behavior disorder preceding Parkinson's disease with therapeutic response to levodopa.

Rapid eye movement (REM) sleep behavior disorder (RBD) involves complex behavior and a loss of muscle atonia occurring during REM sleep. Half of these patients with RBD have an underlying neurologic disorder including dementia, olivopontocerebellar atrophy, subarachnoid hemorrhage, and cerebrovascular disease. Clonazepam is the drug of choice for RBD. RBD has been rarely reported to precede the onset of Parkinson's disease (PD). Three patients are presented here whose RBD preceded the onset of PD by several years, and both the symptoms of PD and RBD improved with levodopa treatment. It is postulated that levodopa ameliorates RBD by suppressing REM sleep, and it remains to be seen whether levodopa can be an alternative to clonazepam in idiopathic RBD without PD.

Aged↗
PubMed1996

Immunosuppressive effects of the cyclosporin derivative SDZ IMM 125 on kidney allograft in the dog and small bowel and pancreas allografts in the rat.

The efficacy of SDZ IMM 125 in preventing allograft rejection was evaluated in kidney transplantation in the dog and orthotopic small bowel and heterotopic pancreas transplantation in the rat. Seven groups (n = 6) were involved in dog kidney transplantation. Untreated recipients rejected kidney allografts with a mean survival time (MST) of 8.0 +/- 1.8 days. There was a graded dose response in SDZ IMM 125-treated groups: 10 mg/kg/day, MST 11.3 +/- 3.5 days, P = 0.065; 15 mg/kg/day, MST 44.8 +/- 10.8 days, P = 0.0001; and 20 mg/kg/day, MST 47.3 +/- 5.6 days, P = 0.0001, same as in cyclosporin A (CsA)-treated groups: 10 mg/kg/day, MST 25.8 +/- 13.7 days, P = 0.001; 15 mg/kg/day, MST 38.3 +/- 18.1 days, P = 0.002; and 20 mg/kg/day, MST 38.7 +/- 17.7 days, P = 0.002. Low dose of SDZ IMM 125 (10 mg/kg/day) was less effective in prolonging the graft survival than low dose of CsA. High dose (20 mg/kg/day) treatment of both SDZ IMM 125 and CsA led to abnormal recipient liver enzymes alanine aminotransferase and aspartate aminotransferase postoperatively. A histopathological study demonstrated fatty degeneration of hepatic cells in both 20 mg/kg/day SDZ IMM 125- and CsA-treated groups. We also tested the effect of SDZ IMM 125 in orthotopic small bowel transplantation with three combinations, namely host-versus-graft (HVG), graft-versus-host (GVH), and combined HVG and GVH immune responses and pancreas transplantation in the rat with different doses. The results indicate that SDZ IMM 125 is a potent immunosuppressant to prolong the kidney allograft survival in the dog, to alleviate HVG and GVH responses in small bowel transplantation, and to delay pancreas allograft rejection in the rat. Low dose of SDZ IMM 125 is less effective than a similar dose of CsA to prevent kidney allograft rejection in the dog.

Animals↗
PubMed1996

Ultrasonographically adjusted midtrimester risk of trisomy 21 and significant chromosomal defects in advanced maternal age.

OBJECTIVE: Our purpose was to determine whether normal midtrimester ultrasonography results reduces the risk of fetal Down syndrome and any clinically significant chromosomal defects in pregnancies with advanced maternal age and to develop risk tables on the basis of age and ultrasonographic results. STUDY DESIGN: Biometry data were obtained in 4079 women between 15 and 24 weeks undergoing amniocentesis for maternal age. Expected values of humerus, femur, both combined, and abdominal circumference based on biparietal diameter were generated from a normal group. Observed/expected values of each parameter and nuchal thickness > or = 6 mm was used to screen for Down syndrome and any clinically significant chromosome defects. Receiver-operator characteristic curves were used to determine threshold screening values for each parameter. By use of stepwise logistic regression the optimal measurements for detection of chromosome anomalies were established. An abnormal ultrasonography result was defined as either abnormal biometry choroid plexus cysts or a structural defect. RESULTS: The finding of shortened humerus (observed/expected < 0.90), abnormal nuchal thickness, or an anatomic defect had the highest sensitivity for Down syndrome detection, 70.6%, p < 0.0001, whereas a short humerus, small abdominal circumference, (observed/expected < 0.92), or an anatomic defect had a sensitivity of 46.7%, p < 0.0001, for any significant chromosome defect. With a normal ultrasonography the risk of Down syndrome in a 39-year-old woman falls from 1:100 to < 1:292. CONCLUSION: A normal ultrasonography substantially reduces the risk of Down syndrome and any chromosome abnormality. This information is useful in counseling women who decline amniocentesis on the basis of maternal age.

Biometry↗
PubMed1996

Risk of Down syndrome and any clinically significant chromosome defect in pregnancies with abnormal triple-screen and normal targeted ultrasonographic results.

OBJECTIVE: Our purpose was to study prospectively the use of ultrasonographic biometry to refine the risk estimates for both Down syndrome and any clinically significant chromosome defect in women with abnormal biochemical triple-screen results. STUDY DESIGN: Ultrasonographic biometry and anatomic survey were performed on study and control cases. Expected values for humerus, femur, combined humerus plus femur lengths, and abdominal circumference were generated on the basis of biparietal diameter obtained from a normal group. Threshold observed/expected values of each measurement for screening for Down syndrome and clinically significant chromosome defects were determined with receiver-operator characteristic curves. By stepwise logistic regression analysis the optimal screening parameters, including nuchal thickness, for detection of Down syndrome and clinically significant chromosome defect were determined. Risk tables for chromosome anomalies were developed on the basis of ultrasonography and triple-screen values. RESULTS: Of 1034 cases at risk for Down syndrome (risk > or = 1/270) or trisomy 18 on the basis of triple-screen results, there were 11 cases of Down syndrome, 1 of trisomy 18, and 17 clinically significant chromosome defects. Abnormal nuchal thickness or observed/expected humerus length < 0.92 was the most sensitive parameter for Down syndrome detection. Abnormal nuchal thickness or observed/expected combined femur and humerus length < 0.90 was the most sensitive for significant chromosome defects. With abnormal biometry or anatomy the Down syndrome risk was 8 of 127 versus 1 of 753 in normals, odds ratio 50.4 (95% confidence interval 6.4 to 90.2), p < 0.00001, and the risk of significant defects was 11 of 90 versus 6 of 830 in normals, odds ratio 19.3 (95% confidence interval 6.4 to 60.5), p < 0.00001. In a pregnancy with a 1 in 270 triple-screen risk for Down syndrome, normal biometric and anatomic results reduce the risk to 1 in 2100. CONCLUSION: Normal ultrasonographic anatomy and biometry significantly reduces the risk of both Down syndrome and any significant chromosome defects in pregnancies with abnormal triple-screen results.

Biochemistry↗
PubMed1995

Ossification of the posterior longitudinal ligament. Autosomal recessive trait.

STUDY DESIGN: This study analyzed the mode of inheritance of ossification of the posterior longitudinal ligament (OPLL) from the pedigree of a family. OBJECTIVES: The results were correlated to provide a new mode of inheritance of OPLL. SUMMARY OF BACKGROUND DATA: Although a nation-wide multicenter survey of OPLL has been carried out in 347 subjects and 1030 relatives in Japan since 1981, no parental consanguinity has been reported. METHODS: In the family, three siblings and one other member of a family underwent operations for OPLL in our department, and the clinical information regarding other family members was obtained from interviews with these four patients or relatives. RESULTS: The parents of three affected siblings and another unaffected sister were first cousins, and the father was suspected to be affected as well. CONCLUSION: Transmission of OPLL as an autosomal recessive trait in this family, which has not been reported, is suspected; although, the possibility that it is a dominant trait can not be excluded.

Aged↗
PubMed1995

Long-term expression of a reporter gene from latent herpes simplex virus in the rat hippocampus.

A problem in utilizing herpes simplex virus (HSV) as a vector for expression of foreign genes in CNS neurons has been the inability to facilitate long-term expression of the engineered genes. Previously, we showed that the murine moloney leukemia virus LTR would drive beta-galactosidase (beta-gal) transcription for extended periods from the latent viral genome in sensory, but not motor neurons. In this communication we further evaluate the utility of the LTR promoter for use in long-term expression vectors. Following stereotactic injection of 8117/43 (an ICP4 minus, non-replicating virus with the LTR driving the beta-gal gene, or KD6 (an ICP4 minus non-replicating virus not expressing beta-gal) into the hippocampus of rats, polymerase chain reaction (PCR) analysis of viral DNA after 2 months indicated that latent infections were established. Assaying by both x-gal staining and reverse transcriptase PCR we demonstrate that (1) beta-gal can be detected for at least 6 months in hippocampal neurons, and (2) although the number of beta-gal transcripts in these cells drops considerably by 2 weeks, they can be detected during the period studied. These studies indicate that the LTR promoter is active and affords long-term expression in the CNS, albeit at comparatively low levels compared to those observed at acute times.

Animals↗
PubMed1995

Percutaneous transluminal coronary angioplasty of an anomalous right coronary artery arising from a separate ostium in the left sinus of Valsalva. A case report.

The authors describe a case of angioplasty in an anomalous right coronary artery arising from an aberrant ostium in the left sinus of Valsalva anterior and slightly superior to the ostium of the left main coronary artery. The patient also had associated bicuspid aortic valve. To the best of their knowledge, this is the first case of angioplasty in an aberrant right coronary artery originating from an ectopic ostium. The choice of guiding catheter and balloon angioplasty catheter is discussed.

Adult↗
PubMed1995

Single coronary artery: a case report and review of current literature.

We present a case of a single coronary artery where the right coronary artery (RCA) arose from its proximal part. This rare anomaly was detected during elective coronary angiography in a patient with suspected coronary artery disease. The single coronary artery originated from the left sinus of valsalva, giving rise to RCA proximally and distally dividing into left anterior descending (LAD), ramus intermedius and left circumflex (LCX) arteries. The anginal symptoms in this patient was attributed to a significant stenosis at the proximal LAD which was subsequently dilated by coronary angioplasty. To the best of our knowledge, this is the first reported case of angioplasty of LAD in an anomalous single coronary artery.

Angioplasty, Balloon, Coronary↗
PubMed1995

[Inhibition of ornithine decarboxylase activity and epidermal papilloma in mice by beta-carotene].

Anticarcinogenic action of beta-carotene was analyzed with determination of ornithine decarboxylase (ODC) activity induced by TPA and a two-stage model of skin papilloma-genesis in mice. Results showed increase of ODC activity induced by TPA could be significantly inhibited, onset of tumor postponed, and number of tumor foci decreased by beta-carotene. It suggested beta-carotene had an obvious chemoprophylactic effect on tumor.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1995

Percutaneous balloon valvuloplasty in mitral restenosis after previous surgical commissurotomy.

OBJECTIVES: The aim of this study was to determine the safety profile, mitral valve outcome and follow-up functional status after percutaneous balloon mitral valvuloplasty (PBMV) in patients with mitral restenosis post-surgical commissurotomy. METHODS: Sixteen patients with symptomatic mitral restenosis after previous surgical commissurotomy underwent valvuloplasty using the Inoue balloon stepwise dilatation method. Echocardiography was performed before and after the procedure to evaluate the mitral valve area. RESULTS: All procedures were successfully completed without cardiac perforation, thromboembolism, resultant severe mitral regurgitation or death. The mitral valve area improved from 0.9 +/- 0.2 to 1.6 +/- 0.3 (p = 0.0001), accompanied by a significant immediate reduction in the left atrial pressure and transmitral gradient. Compared with PBMV in patients without past mitral surgery, patients with mitral restenosis undergoing PBMV experienced less valve area improvement but the difference was not significant (p = 0.137). Optimal valve enlargement resulting in mild mitral stenosis was achieved in 12 of the 16 patients. Midterm symptomatic benefit was observed in almost all patients. CONCLUSIONS: In view of the excellent success rate, low complication risk, the optimal haemodynamic results and favourable functional outcome afforded by mitral balloon valvuloplasty in patients with mitral restenosis after prior surgical commissurotomy, it is logical that balloon mitral valvuloplasty, where available, should be the initial treatment modality in this group of patients with suitable valve morphology before considering repeat mitral surgery.

Adult↗