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Biomedical subjects

S K Lo

Publications and source records attributed to S K Lo.

At least 37 records · Page 2Linked to original sources
PubMed2000

Endoscopic measurement of pancreatic tissue perfusion in patients with chronic pancreatitis and control patients.

BACKGROUND: Pancreatic blood flow is diminished in experimental models of acute and chronic pancreatitis. We attempted to develop a safe and reliable technique for its measurement in patients and to examine blood flow in patients with chronic pancreatitis and in control subjects. METHOD: Pancreatic blood flow was measured using the hydrogen gas clearance technique and an endoscopically placed platinum ductal electrode. Pancreatic blood flow was measured in 12 patients with chronic pancreatitis diagnosed clinically and radiographically, and in 11 control patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) for non-pancreatic pathology. RESULTS: Patients with chronic pancreatitis had a significantly lower pancreatic blood flow compared with control patients (51.5 versus 91.7 mL/min/100 gm, p < 0.01). With secretin stimulation pancreatic blood flow increased in two control patients, whereas this notable rise was not seen in three patients with chronic pancreatitis. CONCLUSIONS: Measurement of pancreatic blood flow with an endoscopically placed electrode is relatively safe and simple to perform. The scarring and vascular fibrosis associated histologically with chronic pancreatitis is reflected in lower pancreatic blood flow.

Adult↗
PubMed2000

Short stature and delayed puberty in gymnasts: influence of selection bias on leg length and the duration of training on trunk length.

BACKGROUND: Delays in bone age, the onset of puberty, and skeletal growth in gymnasts could be, in part, the reason for an interest in gymnastics, rather than being the result of vigorous exercise. We hypothesized that short stature and delayed bone age are present at the start of gymnastics, and training delays growth, producing short stature, even after retirement. METHODS: Sitting height and leg length were measured in 83 active female gymnasts, 42 retired gymnasts, and 154 healthy control subjects. Results were expressed as age-specific SD scores (mean +/- SEM). RESULTS: In the cross-sectional data, active gymnasts had delayed bone age (1.3 +/- 0.1 years), reduced height -1.32 +/- 0.08 SD, sitting height -1.24 +/- 0.09 SD, and leg length, -1.25 +/- 0.08 SD (all P <.001). However, in those training for less than 2 years, the deficit was confined to leg length (-0.8 +/- 0.2 SD). During 2 years of follow-up of 21 gymnasts, only the deficit in sitting height worsened (by 0.4 +/- 0.1 SD). In 13 gymnasts followed up in the immediate 12 months after retirement, sitting height accelerated, resulting in a lessening of the deficit in sitting height by 0.46 +/- 0.14 SD (P <.01). Adult gymnasts who had been retired for 8 years had no deficit in sitting height, leg length, or menstrual dysfunction. CONCLUSIONS: Short stature in active gymnasts is partly due to selection of individuals with reduced leg length. Reduced sitting height is likely to be acquired but is reversible with cessation of gymnastics. A history of gymnastic training does not appear to result in reduced stature or menstrual dysfunction in adulthood.

Adolescent↗
PubMed2000

Epidural ropivacaine with fentanyl following major gynaecological surgery: the effect of volume and concentration on pain relief and motor impairment.

In a prospective, randomized, double-blind study, 40 patients undergoing gynaecological oncology surgery received either 0.1% ropivacaine with fentanyl 1 microgram ml-1 or 0.2% ropivacaine with fentanyl 2 micrograms ml-1. A PCEA pump was set to deliver ropivacaine 8 mg with fentanyl 8 micrograms with each successful demand and a lockout period of 15 min without background infusion. Patients were observed for rest and activity pain VAS, side effect incidence, peak expiratory flow rate (PEFR), leg strength, sensory block to cold and pinprick, and PCEA usage into the second postoperative day. Passive and active pain scores for both groups were both satisfactory and comparable for the duration of the study. There were no differences between groups with regard to side effects. There was a 24% increase in total drug used in the high-concentration/low-volume group (P < 0.05). The study demonstrated that PCEA ropivacaine with fentanyl is an effective means of postoperative analgesia for this patient population. Reduced drug consumption with high-volume/low-concentration solution confirms similar findings by other investigators using alternate local anaesthetic agents, and suggests that the therapeutic ratio of ropivacaine is widened if a low-concentration/high-volume solution is used.

Adult↗
PubMed2000

Tenoxicam i.v. in major gynaecological surgery--pharmacokinetic, pain relief and haematological effects.

This study compared postoperative analgesic dispensation and measures relating to haemostasis following intravenous administration, in a randomized double-blinded manner, of either placebo or tenoxicam 20 mg to 30 women presenting for major gynaecological oncology surgery under a standardized, combined epidural/general anaesthetic technique. Pharmacokinetic disposition of tenoxicam in this patient cohort was also described. There was no objective or subjective alteration in haemostatic function or increase in blood loss, nor any deviation from the normal range of values. Postoperative analgesia during the first 48 hours was delivered to achieve a VAS endpoint of less than five on leg-raising, by a combination of a nurse-controlled low-dose background epidural infusion and patient-administered epidural bolus. Greater VAS variability was observed during the first four postoperative hours (P = 0.08). The tenoxicam group self-administered significantly fewer epidural bolus doses to maintain satisfactory analgesia compared with the placebo group during the first 24 hours (P = 0.004) and 48 hours (P = 0.01) postoperatively. Similar differences between the groups in the total dose of the epidural bupivacaine/fentanyl mixture delivered were described (4 h: P = 0.148; 24 h: P = 0.033; 48 h: P = 0.001) (Figure 2). Despite surgery, transfusion and the use of a renal protective fluid administration strategy, tenoxicam disposition was not greatly different from that widely described for healthy volunteers. There were no significant side-effects and no adverse events attributable to tenoxicam. In this small study we have shown that tenoxicam administered preoperatively reduced the epidural analgesic requirements during the first 48 hours following major gynaecological surgery. There was no clinical or pathological evidence of haematological impairment following a single i.v. administration of tenoxicam 20 mg.

Aged↗
PubMed2000

Comparing Norton, Braden and Waterlow risk assessment scales for pressure ulcers in spinal cord injuries.

When pressure ulcers occur health care services are faced with considerable challenges and costs. Additionally these ulcers cause significant physical and psycho-social impairment for patients and their families. The complexity of pressure ulcer management is widely acknowledged in the literature. However, the applicability of the major risk assessment scales in the context of spinal cord injury has not been explored. Retrospective case history audit of individuals with pressure ulcers provided data to compare the three commonly used Norton, Braden and Waterlow scales. Waterlow's scale was the most sensitive of the three scales compared.

Adolescent↗
PubMed2000

DNA polymorphisms at the apolipoprotein A1-CIII loci in Taiwanese: correlation of plasma APOCIII with triglyceride level and body mass index.

BACKGROUND AND PURPOSE: Apolipoprotein (APO) A1-CIII genes are linked within a 2.6-kb region on human chromosome 11. ApoA1 is the main component of high-density lipoprotein (HDL), and apoCIII inhibits lipoprotein lipase activity. Genetic variations in APOA1-CIII may affect the function of apoA1/apoCIII and plasma lipid/lipoprotein levels, and thus, the risk of developing atherosclerosis. This study compared the frequency distributions of genetic variations in APOA1-CIII genes and their influence on plasma lipid concentrations in Taiwanese patients with coronary artery disease (CAD) and in healthy controls. METHODS: Six restriction site variations (RSVs) of the APOA1-CIII gene complex were investigated by DNA amplification using polymerase chain reaction and restriction enzyme digestion in 229 control subjects and 131 CAD patients during the period from 1992 through 1996. The blood lipid profiles of these subjects were also determined. RESULTS: Thirty-seven distinct six-RSV genotypes were observed. Separate comparisons of the frequency distributions of the six genetic variations showed no significant differences between CAD patients and controls subjects, but the combined six-RSV-genotypes showed different frequency distributions between these two groups. Nine of the 37 six-RSV genotypes were found only in the CAD patients and higher frequencies of two of these types were observed in the CAD patients than in healthy controls. The effects of these genetic variations were on high-density lipoprotein cholesterol in women (for MspIB, PstI, SstI and PvuII RSV) and total cholesterol (for PvuII RSV), low-density lipoprotein cholesterol (for XmnI RSV), and apolipoprotein B (for MspI and SstI RSV) levels in men in the control group. Elevated plasma apoCIII concentration was significantly associated with an increased plasma triglyceride level and body mass index in the control group (P < 0.0001). CONCLUSIONS: Analysis of the frequency distribution of six RSVs of the APOA1-CIII gene complex in Taiwanese CAD patients and control subjects showed that the effect of genotype on plasma lipid levels was gender-specific and that the apoCIII level was closely associated with plasma triglyceride level and body mass index.

Alleles↗
PubMed1999

A case-controlled MRI/MRA study of neurovascular contact in hemifacial spasm.

BACKGROUND: Neurovascular contact (NVC) with the root exit zone (REZ) of the ipsilateral facial nerve is associated with hemifacial spasm (HFS), but unresolved issues remain. OBJECTIVES: To 1) determine the frequency of symptomatic and nonsymptomatic NVC, 2) determine the features of NVC associated with HFS, and 3) correlate severity of HFS to these features. METHODS: Two independent, blinded, prospective assessments of high-resolution MR and MR angiography (MRA) images were performed on Chinese cases (HFS: n = 44; age-matched control subjects: n = 20). RESULTS: Over 88% of 44 symptomatic sides in patients with HFS had NVC of the ipsilateral facial nerve. At least 80% of symptomatic sides involved NVC at the anterior aspect of the REZ [REZ(ant.)]. Although NVC was observed in approximately half of nonsymptomatic sides, at least 70% of them were not at REZ(ant.). NVC at the cisternal and intracanalicular portions of the facial nerve were not associated with HFS. Half of our patients with HFS had bilateral NVC, but none had bilateral symptoms. Most of our MR/MRA images showed that the size and position of the arterial branches of the vertebrobasilar system were markedly asymmetric. Of patients with bilateral NVC, over 83% had asymmetric NVC sites. The anterior inferior cerebellar artery was the most common vessel involved in NVC, but was not significantly associated with HFS. Most of the NVC involved one vessel at one contact point with no indentation. The development of HFS was significantly associated with nerve indentation in NVC. The development and severity of HFS were not associated with multiple contact points in NVC. No significant interobserver variability existed between the blinded assessments. CONCLUSIONS: MRI/MR angiography are accurate, fast, and safe in characterizing neurovascular contact (NVC) at the brainstem. The site of NVC and ipsilateral facial nerve indentation in NVC are significant determinants for the development of hemifacial spasm (HFS). The lack of bilateral NVC at the anterior aspect of the root exit zone of the facial nerve could explain in part the lack of bilateral symptoms. The development and severity of HFS are not associated with a specific blood vessel or multiple contact points in NVC.

Adult↗
PubMed1999

Physical activity, water intake and risk of colorectal cancer in Taiwan: a hospital-based case-control study.

The age-adjusted mortality rates of colorectal cancer have been rising in Taiwan over the past 2 decades, and colorectal cancer is now the third leading cause of cancer mortality in the country. We conducted a hospital-based case-control study to clarify the nature of the association between physical activity, water intake and colorectal-cancer risk in Taiwan. A total of 163 subjects (aged 33-80 years) with histologically confirmed primary colorectal cancer and 163 hospital controls were enrolled during 1992. Dietary intake, physical activity and other lifestyle activities were assessed using a comprehensive food-frequency and lifestyle-activity questionnaire. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic-regression analysis. A strong inverse dose-response relation between increased water intake and rectal cancer was found among men after adjustment for other risk factors (p for trend = 0.0005). The OR for rectal cancer among men in the highest tertile of water intake was 0.08 (95% CI, 0.02-0.35) compared with that among men in the lowest tertile (OR = 1). Similar but not significant trends were seen among women (p = 0.29). The OR for colon cancer among men with active leisure-time physical activity was 0.19 (95% CI, 0.05-0.77) times that among sedentary men (p for trend = 0.03). However, physical activity was not associated with colon-cancer risk among women (p = 0.48). No differences in the amount of water intake were found related to level of physical activity. These findings add to the evidence that leisure-time activity may reduce colon-cancer risk, not only in high-risk but also in low-risk populations, and support the potential beneficial effect of increased water intake in reducing colorectal-cancer risk.

Adult↗
PubMed1999

Insufficiently active Australian college students: perceived personal, social, and environmental influences.

BACKGROUND: A sustainable pattern of participation in physical activity is important in the maintenance of health and prevention of disease. College students are in transition from an active youth to a more sedentary adult behavior pattern. METHODS: We assessed self-reported physical activity and other characteristics in a sample of 2,729 male and female students (median age was 20 years) recruited from representative courses and year levels at four Australian College campuses. They were categorized as sufficiently or insufficiently active, using estimates of energy expenditure (kcal/week) derived from self-reported physical activity. Personal factors (self-efficacy, job status, enjoyment), social factors (social support from family/friends), and environmental factors (awareness of facilities, gym membership) were also assessed. RESULTS: Forty-seven percent of females and 32% of males were insufficiently active. For females, the significant independent predictors of being insufficiently active were lower social support from family and friends, lower enjoyment of activity, and not working. For males, predictors were lower social support from family and friends, lower enjoyment of activity, and being older. CONCLUSIONS: Factors associated with physical activity participation (particularly social support from family and friends) can inform physical activity strategies directed at young adults in the college setting.

Adolescent↗
PubMed1999

Suppression of hepatitis C virus by hepatitis B virus in coinfected patients at the National University Hospital of Singapore.

This study was carried out to compare hepatitis B virus (HBV) and hepatitis C virus (HCV) replicative states and to determine possible interference between HBV and HCV. One thousand and sixty-one consecutive patients seen at The Gastroenterology Division of the National University Hospital of Singapore between 1988 and 1995 were screened for HBV and HCV serological markers. Anti-HCV was tested using a second-generation enzyme-linked immunosorbent assay (ELISA) method. HCV-RNA was detected by a reverse-transcription polymerase chain reaction method (RT-PCR). Data were analyzed by either paired t-test or chi2 test. Two hundred and twenty-four patients were infected with HBV alone, while 117 patients were infected with HCV only. Thirty-one patients were coinfected with HBV and HCV. HCV-RNA was detected in 104 of the 117 HCV patients (88.9%), and in 12 of 29 coinfected patients (41.4%). Serum anti-HCV levels in the coinfected patients were lower than those in the HCV-infected patients. A significant difference for anti-HCV reactivity and HCV-RNA positivity was observed between HCV-infected patients and coinfected patients (P < 0.01). In contrast, HBV-DNA and hepatitis B envelope antigen (HBeAg) positive rates were similar in HBV carriers and patients coinfected with HBV and HCV. These results show a possible interaction between HBV and HCV life cycles, and suggest that HCV replication may be negatively affected by HBV.

Adult↗
PubMed1999

Detection of pre-S/S gene mutants in chronic hepatitis B carriers with concurrent hepatitis B surface antibody and hepatitis B surface antigen.

Hepatitis B virus (HBV) with various mutations has been reported. The frequency of the natural occurrence of such variants and whether the heterogeneity of these genomic regions correlates with a specific serologic pattern of concurrent hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (anti-HBs) were investigated. We analyzed the perS/S regions of HBV in six asymptomatic HBV carriers who were seropositive for both HBsAg and anti-HBs (group A), four hepatocellular carcinoma (HCC) patients with concurrent HBsAg and anti-HBs (group B), and five asymptomatic HBV carriers without anti-HBs as controls (group C). PreS/S regions of HBV-DNA were amplified by polymerase chain reaction (PCR), cloned, and sequenced. The results showed that, in some of the samples, a few deletions and numerous point mutations were presented in preS/S regions. One of the HBV carriers with anti-HBs (group A) and an HCC patient with anti-HBs (group B) had point mutations in the "a" determinant, resulting in conversion from Ile-126 of wild-type to Asn-126. The patients with anti-HBs (groups A and B) had a significantly greater divergence rate of amino acid for the preS/S gene compared with controls. Our results suggested that the HBV mutants observed in the preS/S gene may have led to changes in the immunogenicity of the viral particles, and thus influence the viral behavior and clinical course. Therefore, some HBV patients with concurrent HBsAg and anti-HBs may be HBV S mutants.

Adult↗
PubMed1999

Hot spot mutations in morphological transforming region II (ORF 79) of cytomegalovirus strains causing disease from bone marrow transplant recipients.

Nested polymerase chain reaction (PCR) amplifying the morphological transforming region II (mtrII) of cytomegalovirus (CMV) has been shown to be useful in the detection of CMV DNA in bone marrow transplant (BMT) recipients. However, there has never been any report on mutation hot spots and subtypes of this open reading frame. Using primers derived from sequences upstream and downstream of mtrII (ORF 79), CMV DNA from peripheral blood leukocytes (PBL) and conventional CMV culture of 16 BMT recipients were amplified by PCR, cloned into pUC118, and sequenced. The amino acid sequences were predicted using the standard triplet code. The DNA sequences obtained from direct amplification of CMV in PBL obtained from the 16 patients were 100% identical to the corresponding ones obtained by amplification of CMV DNA extracted from conventional CMV culture. Within mtrII (ORF 79), hot spot single base mutations were observed at positions +40 (G-->A), +123 (A-->G), +213 (T-->C), and +219 (T-->C). However, because of third base degeneracy, only amino acid 14 was changed from valine to isoleucine in the predicted protein of 13 patients. This corresponded to the hot spot mutation at position +40 (GTC-->ATC), while the rest were silent mutations. An insertion of 3 bases (ACG) was observed in the CMV DNA of 10 patients at positions +91 to +93, leading to a threonine insertion at amino acid 31 in these patients. For patient no. 147 there was a 65 bp deletion in the CMV DNA amplified later in the course of BMT as compared with that early in the course. This gave rise to a frame shift mutation and a change of more than 70% in the predicted amino acid sequence of the protein.

Amino Acid Sequence↗
PubMed1999

Neutrophil inhibitory factor abrogates neutrophil adhesion by blockade of CD11a and CD11b beta(2) integrins.

We studied the basis of inhibition of polymorphonuclear leukocyte (PMN) adhesion induced by neutrophil inhibitory factor (NIF), a 41-kDa CD11/CD18 beta(2) integrin-binding protein isolated from the canine hookworm (Ancylostoma caninum). NIF blocked PMN adhesion in a concentration-dependent manner with complete blockade occurring at approximately 10 nM NIF. Because CD11a and CD11b beta(2) integrins are functionally active on stimulated PMNs, and yet NIF is postulated to inhibit only CD11b integrin by binding to its I domain, we evaluated the contributions of CD11a and CD11b beta(2) integrins in the mechanism of inhibition of PMN adhesion to endothelial cells. We observed an additive inhibitory effect (>90% inhibition) of PMN adhesion to endothelial cells when NIF was used in combination with anti-CD11b monoclonal antibodies, which alone at saturating concentrations reduced PMN adhesion by only 50%. NIF also prevented aggregation of phorbol ester-stimulated JY lymphoblastoid cells that expressed only the functionally active CD11a, suggesting that NIF also can inhibit CD11a-dependent response. We transduced the NIF cDNA into human dermal microvessel endothelial cells in which NIF synthesis and release prevented PMN adhesion to the transduced human dermal microvessel endothelial cells. These data indicated that the potent antiadhesive effect of NIF may be the result of inhibition of CD11a and CD11b beta(2) integrins on PMNs. Moreover, the strategy of NIF release from transduced endothelial cells suggests the feasibility of blocking the CD11a- and CD11b beta(2) integrin-dependent PMN adhesion and PMN migration responses specifically at sites of endothelial cell activation.

Animals↗
PubMed1999

Nucleic acid-based cross-linking assay for detection and quantification of hepatitis B virus DNA.

A nucleic acid photo-cross-linking technology was used to develop a direct assay for the quantification of hepatitis B virus (HBV) DNA levels in serum. Cross-linker-modified DNA probes complementary to the viral genomes of the major HBV subtypes were synthesized and used in an assay that could be completed in less than 6 h. The quantification range of the assay, as determined by testing serial dilutions of Eurohep HBV reference standards and cloned HBV DNA, was 5 x 10(5) to 3 x 10(9) molecules of HBV DNA/ml of serum. Within-run and between-run coefficients of variation (CVs) for the assay were 4. 3 and 4.0%, respectively. The assay was used to determine HBV DNA levels in 302 serum samples, and the results were compared to those obtained after testing the same samples with the Chiron branched-DNA (bDNA) assay for HBV DNA. Of the samples tested, 218 were positive for HBV DNA by both assays and 72 gave results below the cutoff for both assays. Of the remaining 12 samples, 10 were positive for HBV DNA by the cross-linking assay only; the 2 other samples were positive by the bDNA assay only. Twenty-eight samples had to be retested by the bDNA assay (CV, >20% between the results obtained from the testing of each sample in duplicate), whereas only three samples required retesting by the cross-linking assay. The correlation between the HBV DNA levels, as measured by the two tests, was very high (r = 0.902; P = 0.01). We conclude that the cross-linking assay is a sensitive and reproducible method for the detection and quantification of HBV DNA levels in serum.

Cross-Linking Reagents↗
PubMed1999

Metallic stenting for colorectal obstruction.

Intestinal obstruction is a major complication of colorectal cancer. Acute surgical decompression frequently requires subsequent operative interventions and is associated with mortality in more than 3% of the cases. Transanal metallic stenting is now possible to perform on an outpatient basis, thus providing quick symptom relief and the opportunity to cleanse the bowel for work-up or surgery. This stenting provides temporary relief for patients and is gaining acceptance rapidly. Randomized controlled trials are needed to help pinpoint refinements that can minimize the difficulty of stent insertion.

Biocompatible Materials↗