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Biomedical subjects

J S Woo

Publications and source records attributed to J S Woo.

At least 37 records · Page 2Linked to original sources
PubMed1996

The best gastric site for obtaining a positive rapid ureas test.

BACKGROUND: Rapid ureas tests (RUTs) provide a simple, sensitive method of detecting Helicobacter pylori infection. OBJECTIVES: Our aim, therefore, was to determine whether the yield of detecting H. pylori infection by RUT varied depending on the site of gastric biopsy. MATERIALS AND METHODS: Gastric biopsies were obtained from 50 patients for RUT by use of hpfast (GI Supply, Camp Hill, PA). Biopsies were taken from the prepyloric greater curve antrum, from the gastric angle, and from the greater curve in mid-corpus. One biopsy specimen was placed in the RUT gel, and the biopsy from the adjacent mucosa was placed in formalin for subsequent histological evaluation by using the Genta stain. RUTs were examined and scored at intervals of 5, 10, 15, 30, and 45 minutes and after 1, 2, 4, and 24 hours. RESULTS: Fifty patients were entered in the rest (150 RUTs), 32 having H. pylori infection. There were no false-positive RUTs (specificity, 100%). The gastric angle site was positive in 100%. The prepyloric site was positive in 87%, and the corpus site was positive in 84.4% (p < .052 for angle or prepyloric antrum versus corpus). The most common pattern was for all to be positive (74%). The median time to positivity was similar with angle and prepyloric sites (37.5 and 60 minutes, respectively, p = not significant) and shorter than the corpus biopsy (180 minutes); (p < .05 for angle or prepyloric antrum versus corpus). CONCLUSION: The maximum probability for detecting H. pylori infection using a RUT is to obtain a biopsy from the gastric angle. To prevent missing a positive result when intestinal metaplasia is present, we recommend that (at a minimum) biopsies be taken from both the angle and the corpus.

Bacterial Proteins↗
PubMed1995

Effect of cisplatin on renal function in rabbits: mechanism of reduced glucose reabsorption.

This study was performed to determine the effect of cisplatin (cis-diamminedichloroplatinum II) on renal function in rabbits. Injection of a single i.p. dose of 4 mg/kg cisplatin caused an increase in fractional excretion of Na+ and K+ and a decrease in urine osmolality (Uosm), free-water reabsorption, (TcH2O), and urine to plasma creatinine ratio (U/Pcr). Urine flow was decreased following cisplatin treatment, which was accompanied by marked reduction in GFR. Cisplatin induced glucosuria, phosphaturia, and aminoaciduria. These results suggest that cisplatin results in impaired proximal tubular reabsorptive function and the renal concentrating defect. Cisplatin treatment impaired the accumulation of PAH and TEA and ouabain-sensitive oxygen consumption in renal cortical slices. Na(+)-K(+)-ATPase activity in renal cortical microsomes and basolateral membrane vesicles was significantly depressed in cisplatin-treated animals. Cisplatin treatment did not affect the Na(+)-dependent uptake of glucose and L-glutamate by brush-border membrane vesicles (BBMV), but caused a significant decrease in Na(+)-dependent succinate and H(+)-dependent TEA uptake. Morphological observations showed that cisplatin caused a focal loss of the microvillus brush border. These results suggest that (1) cisplatin induces oliguric acute renal failure in rabbits and (2) glucosuria induced by cisplatin was not due to a direct impairment of glucose transporter in brush-border membranes but due to an inhibition of Na(+)-pump activity and a decrease in area for active glucose reabsorption in the proximal tubule.

Amino Acids↗
PubMed1995

Effect of renal ischaemia on organic compound transport in rabbit kidney proximal tubule.

This study was carried out to determine the effect of renal ischaemia on transport systems for organic compounds in the rabbit kidney proximal tubule. Ischaemia for 30 or 60 min. induced glucosuria and phosphaturia, which was accompanied by polyuria and natriuresis. The Na(+)-dependent uptake of glucose, succinate and L-glutamate by brush-border membrane vesicles was not altered by 30 or 60 min. of ischaemia, while the H+/tetraethylammonium antiport was significantly inhibited after 30 min. of ischaemia. When the duration of ischaemia was extended to 120 min. the uptake of glucose and succinate by brush-border membrane vesicles was also significantly attenuated, but the L-glutamate uptake was not altered. The uptake of glucose, succinate and L-glutamate by basolateral membrane vesicles was not impaired even with 120 min. of ischaemia, suggesting that transport systems for organic compounds in the brush-border membrane are more sensitive to ischaemia than those in the basolateral membrane. Ouabain-sensitive oxygen consumption in renal cortical slices was not depressed by 60 min. of ischaemia. When kidneys were reperfused for 60 min. following 60 min. of ischaemia, the Na(+)-glucose and Na(+)-succinate cotransport and the H+/tetraethylammonium antiport were not different from the control, but the recovery of alkaline phosphatase was significantly reduced. When kidneys were subjected to ischaemia for 60 min., a loss of brush-border microvilli and plasma membrane was observed after 5 or 60 min. of reflow in the proximal convoluted tubule. After 3 hr of reflow, focal necrosis appeared although the microvilli were partially regenerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1994

Revascularization of the ischemic colon transplant using the internal mammary vessels.

We describe a successful reconstruction of the esophagus with the isoperistaltic right colon and terminal ileum, which had very poor continuity of the marginal artery. The stomach and the left colon were not available because of corrosive injury and intraabdominal adhesions. The blood supply of the ischemic transplant was augmented by anastomosis of the internal mammary vessels to the iliocolic vessels.

Adult↗
PubMed1994

Solitary rectal ulcer syndrome.

We report three cases of solitary rectal ulcer syndrome (SRUS). The diagnosis was established according to histopathologic criteria. But, the initial clinical diagnosis was carcinoma, non-specific ulcer and localized proctitis respectively. SRUS is considered as one of functional disorder in pelvic floor which might go underdiagnosed due to unfamiliar concept in Korea. So we should consider SRUS to be one of the differential diagnosis in cases of complaining anorectal symptoms.

Diagnosis, Differential↗
PubMed1994

Effect of t-butylhydroperoxide on p-aminohippurat uptake in rabbit renal cortical slices.

OBJECTIVES: Oxygen free radical (superoxide radical, hydrogen peroxide, and hydroxyl radicals) have been considered to be responsible for the pathogenesis of ischemia reperfusion injury and toxic chemical injury in a variety of organs including myocardium, brain, intestine and kidneys. In in vitro models using a suspension of rat proximal tubule segments, t-butylhydroperoxide(t-BHP), a potent oxidant, induces the severity of tubular dysfunction as reflected by decreases in tubular respiration which is associated with a progressive increase in lipid peroxidation. The precise mechanism of t-BHP-induced cell injury remains to be determine. The study was carried out to determine the effect of oxygen free radicals on organic anion transport in renal proximal tubule. METHODS: By renal cortical slices, we studied accumulation of organic ions, PAH efflux oxygen consumption, lactate dehydrogenase (LDH), lipid peroxidation. The data are expressed as the mean +/- SE and evaluated for significance using Student's t-test. A probability level of 0.05 was used to establish significance. RESULTS: Effect of t-butylhydroperioxide(t-BHP), a potent oxidant, on organic anion p-amminohippurate(PAH) uptake was studied in rabbit renal cortical slices. t-BHP inhibited irreversibly PAH and organic cation tetraethylammonium(TEA) uptake in a dose dependent manner with IC50 of approximately 1.0 and 0.85 mM, respectively. The efflux rate constant pf PAH was not altered by the presence of 1 mM t-BHP, indicating that the inhibitory effect of t-BHP on the steady-state accumulation of PAH is due primary to the reduction in the influx of PAH across the basolateral membrane. The kinetic analysis showed that 1mM t-BHP caused a significant reduction in the maximum rate of PAH influx(Vmax) from 1.54 +/- 0.74 to 0.72 +/- 0.54 umol/g/10 min without an effect on Km, indicating that t-BHP depressed PAH influx across the basolateral membrane by reducing the number or turnover rate of active carrier for PAH transport, but not by altering substrate affinity of the carrier. Ouabain-sensitive and -insensitive oxygen consumption was not different between the control and t-BHP-treated slices. t-BHP caused an increase in LDH release and lipid peroxidation in a dose-dependent manner, which were highly correlated with changes in PAH uptake. CONCLUSION: These results suggest that t-BHP inhibition of PAH uptake is attributed to renal tubular cell damage and lipid peroxidation plays an important role in the inhibitory effect of t-BHP on PAH transport in rabbit proximl tubules.

Animals↗
PubMed1990

Transport of organic compounds in renal plasma membrane vesicles of cadmium intoxicated rats.

Effects of cadmium intoxication on renal transport systems for various organic compounds were studied. Subcutaneous injections of CdCl2 (2 mg Cd/kg.day) for two to three weeks induced marked polyuria, glycosuria, and proteinuria without altering glomerular filtration rate. In renal cortical brush border membrane vesicles (BBMV) isolated from cadmium treated rats, Na(+)-dependent D-glucose uptake was markedly attenuated, and this was due to reduction in Vmax and not Km. Likewise, Na(+)-driven L-glutamate transport and H(+)-driven tetraethylammonium transport were significantly reduced. In renal cortical basolateral membrane vesicles (BLMV) of cadmium intoxicated rats, Na(+)-dependent succinate transport was drastically reduced. These results indicate that cadmium intoxication impairs various transport systems for organic compounds in the brush border and basolateral membranes of proximal renal tubules.

Cadmium Poisoning↗
PubMed1988

Maternal determinants of birthweight in normal pregnancy.

Partial and multiple regression analysis was performed to find out the correlation between birthweight and maternal anthropometric variables. Pearson regression analysis revealed significant dependence of birthweight on gestation of pregnancy, maternal weight, symphysis-sternal distance and height, but not on armspan and skin thickness. However, the only maternal variable bearing significant influence on birthweight in partial regression analysis was bodyweight. The effects of maternal determinants on birthweight, though some of them were statistically significant, were clinically unimportant.

Anthropometry↗
PubMed1987

Characteristic pattern of Doppler umbilical arterial velocity waveform in conjoint twins.

Doppler blood flow studies in a pair of conjoint twins at 18 weeks gestation revealed a characteristic 'double layer' spectral velocity waveform from the umbilical arteries. This is the result of signals originating from 2 separate arterial supplies adjacent to each other in a single umbilical cord. Such a characteristic feature provides an additional sonographic sign in the diagnosis of conjoint twins.

Adult↗
PubMed1987

Doppler blood flow velocity waveforms in alpha-thalassemia hydrops fetalis.

Doppler shift blood flow velocity-time waveforms in the umbilical arteries (UA), aorta (A), and inferior vena cava (IVC) in eight fetuses with alpha-thalassemia (alpha-thal) hydrops fetalis were described. The UA waveforms in these fetuses with anemia in utero depicted a hyperdynamic circulatory state with a relative increase in acceleration slope, more linear decline from maximum systole to end diastole, and reduced spectral broadening. The aortic waveforms similarly displayed distorted systolic peaks, flow turbulence, and greatly elevated diastolic frequencies. Reversal of end diastolic flow in the IVC also indicated cardiac decompensation in these fetuses. Progressive changes in these waveforms were apparent in two fetuses that had serial evaluation. In another four fetuses in which alpha-thal major was diagnosed in the second trimester by DNA analysis and had Doppler evaluation before termination of pregnancy, consistent changes in the UA, A, and IVC waveforms were not observed. This study confirms the potential usefulness of Doppler spectral waveforms in depicting altered hemodynamic changes in the fetus and in the evaluation of hydrops fetalis. Doppler ultrasound examination can be included as part of the routine workup of hydrops fetalis.

Aorta, Thoracic↗
PubMed1987

Significance of an absent or reversed end diastolic flow in Doppler umbilical artery waveforms.

The outcome of nine fetuses in whom Doppler umbilical arterial velocity-time waveforms showed absence or reversal of flow in end diastole was presented. Eight of the nine resulted in either intrauterine or neonatal death. Progressive deleterious changes in the waveforms were evident in three fetuses who had serial evaluation. The remaining infant survived when delivery was expected 2 days later. Our data have indicated that the demonstration of an absent or reversed flow in end diastole in the umbilical arteries carries with it a very specific indication of serious fetal compromise and the need for immediate delivery, although the prognosis of a normal neonatal survival remains guarded.

Blood Flow Velocity↗
PubMed1987

Middle cerebral artery Doppler flow velocity waveforms.

Doppler flow velocity-time waveforms of the middle cerebral arteries at their origin from the internal carotid arteries were obtained serially on 14 patients to determine the alterations of these waveforms with gestational age. Satisfactory recordings were obtained from all patients. The middle cerebral artery waveforms demonstrated a typically biphasic pattern with continuing forward flow in diastole. The peak systolic to end-diastolic ratio (A/B ratio) showed a progressive and significant decline from 6.89 +/- 1.48 at around 25 weeks to 4.23 +/- 0.67 at term. Elevation of diastolic velocities and diminished A/B ratio in the middle cerebral arteries were noted in four fetuses, in whom severe antepartum compromise was diagnosed. The ratio also appeared to decrease with worsening of fetal condition. Because the fetus compensates for hypoxia by increasing blood flow to the brain, Doppler middle cerebral artery waveforms may permit evaluation of fetal compromise and hypoxia.

Blood Flow Velocity↗
PubMed1986

Non-resolution of pelvic sonographic abnormality after chemotherapy for persistent trophoblastic disease--a word of caution.

A case of persistent trophoblastic disease (PTD) is presented in whom pelvic sonography demonstrated persistent uterine abnormality and dilated adnexal vessels after cessation of chemotherapy. Hysterectomy was performed on account of subsequent uterine bleeding. A viable tumour was not demonstrated in the hysterectomy specimen. In the absence of haemorrhagic complications persistent sonographic abnormality should not necessarily indicate hysterectomy, especially when hCG levels are normal.

Adult↗
PubMed1986

Intrauterine growth standards for Hong Kong Chinese.

Intrauterine growth standards for Hong Kong Chinese were derived from birth-weight data between 28 and 42 weeks' gestation in 15,815 livebirths delivered in 1982 to 1984 at 2 maternity teaching hospitals in Hong Kong. Normal distribution of birth-weights was noted in each of the gestational weeks studied. The mean birth-weight was 3,237g at 40 weeks which was similar to the mean weights reported in other populations for this gestation. The trend of the median weight curve was also similar to that in other Caucasian and Asian reports. The growth pattern for males and females were similar and males were on the whole heavier than females throughout the gestational period studied. At 40 weeks, the 10th percentile weight also showed wide variations between reports, which would have important bearing on the studying of intrauterine growth retardation. When the mean weight at term as derived from the present study was compared to a previous report on birth-weight data in 1970-1972 in the same hospital, a significant increase in birth-weight was observed over the 12-year period. The importance of having up-to-date intrauterine weight standards for a specific population is discussed.

Asian People↗
PubMed1986

Fractional spine length: a new parameter for assessing fetal growth.

Sonographic measurement of a segment of the lower thoracic and lumbar fetal spine was performed on 218 normal fetuses of between 15 and 42 weeks' gestational age (GA) to establish a new parameter for assessing fetal growth. The increase of the fractional spine length (FSL) was represented by the equation: FSL = -37.62 + 4.36 (GA) - 0.04 (GA)2, with R2 = 0.92. The FSL also correlates strongly with fetal femur length (FL): FSL = 5.36 + 0.82 (FL), with R2 = 0.93. The ratio FSL/abdominal circumference (AC) X 100 was relatively constant at 20.4 +/- 3.1 (mean +/- 2 standard deviations) from 19 to 42 weeks in contrast to the ratio FL/AC X 100, which was constant at 22.3 +/- 2.4 (mean +/- 2 SD) only after 23 weeks. Nine of 10 small-for-gestational age fetuses examined during the study had a FSL within the normal range, as well as two fetuses who were thanatophoric dwarfs. The FSL provides a new ultrasonic longitudinal measurement of the fetus which may be used in addition to the femur length in fetal growth assessment.

Abdomen↗
PubMed1986

An evaluation of fetal weight prediction using a simple equation containing the fetal femur length.

The accuracy of sonographic fetal weight estimation based on five published regression equations and two new equations generated from data at the authors' institution was evaluated on 41 small-for-gestational age (SGA) fetuses and 57 appropriate-for-gestational age (AGA) fetuses. Equations which contained the fetal femur length (FL) in addition to the biparietal diameter (BPD) and abdominal circumference (AC) yielded lower systematic and random errors in the SGA group but not in the AGA group. These findings support the contention that consideration of the FL is important in sonographic estimation of fetal weight in the growth-retarded fetus as head and limb growth may be affected to different degrees in different fetuses. A new equation, where birthweight in grams = 1.4 X (BPD(cm) X AC(cm) X FL(cm)) - 200, was developed which had a standard deviation of 98 g/kg in SGA fetuses and 68 g/kg in AGA fetuses. This equation yielded significantly lower random errors in the SGA but not in the AGA fetuses when compared with another linear equation without the FL. The new model is simple and practical to use, which makes it a viable alternative to more elaborate models containing three parameters.

Abdomen↗