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Biomedical subjects

W S Lee

Publications and source records attributed to W S Lee.

At least 19 recordsLinked to original sources
PubMed2000

Airway obstruction caused by a congenital epiglottic cyst.

Congenital epiglottic cyst is a rare affliction with potential for airway obstruction. A newborn boy was referred to our department for evaluation of respiratory distress and inspiratory stridor 7 h after birth. Through a transnasal fiberoptic laryngoscopy examination, a diagnosis of an obstructive upper laryngeal cyst was made. Immediate endoscopic surgery was performed 20 h after birth to completely remove the lesion. Two days after surgery, the patient resumed normal breathing pattern and showed no further episodes of stridor or airway obstruction.

Airway Obstruction↗
PubMed2000

Pregnancies and deliveries after in vitro maturation culture followed by in vitro fertilization and embryo transfer without stimulation in women with polycystic ovary syndrome.

OBJECTIVE: To improve the efficacy of an IVF-ET program for unstimulated patients with polycystic ovary syndrome (PCOS) with the use of culture for oocyte maturation. DESIGN: Prospective studies with the comparison of different ET procedures from March 1995 through February 1998. SETTING: University-affiliated hospital. PATIENT(S): Ninety-four cycles in 64 consenting patients with PCOS. INTERVENTION(S): Immature oocytes were retrieved from unstimulated patients with PCOS and subsequently cultured and fertilized in vitro. Zygote intrafallopian transfer (ZIFT), uterine ET, or a combined approach of ZIFT + uterine ET was subsequently performed. MAIN OUTCOME MEASURE(S): Laboratory and clinical data. RESULT(S): Among 1, 280 immature oocytes (13.6 +/- 7.5 oocytes per patient) retrieved, 89% (1,139) were morphologically normal, and 62.2% (708/1,139) of the normal oocytes matured in vitro after culture for 48 hours. When intracytoplasmic sperm injection was performed, 68% (481/708) developed to the normal pronuclear stage, and 88.1% of the embryos cocultured with Vero cells (266/302) cleaved. Eighty-five ET cycles were conducted and pregnancy was established in 23 cycles (27.1%), which consisted of 8 after uterine ET and 15 after a combined approach. Seventeen patients delivered 20 normal infants. CONCLUSION(S): The IVF-ET method using no ovarian stimulation followed by in vitro maturation culture can be a feasible assisted reproductive technology for treatment of PCOS with various complications.

Adult↗
PubMed2000

The predictive value of uvulo-palatoglossal junctional ulcers as an early clinical sign of exanthem subitum due to human herpesvirus 6.

BACKGROUND: The clinical sign of uvulo-palatoglossal junctional (UPJ) ulcers was first noted in 1983 in a 5.5-month-old baby with exanthem subitum (ES). An earlier prospective clinical study showed that there was a strong association of UPJ ulcers and occurrence of ES with a positive predictive value of 95.3% and negative predictive value of 100%. OBJECTIVE: To determine the value of uvulo-palatoglossal junctional (UPJ) ulcers as an early clinical sign of exanthem subitum (ES) due to human herpesvirus 6 (HHV 6) infection. STUDY DESIGN: A case-control study of 20 febrile children with UPJ ulcers versus 26 febrile children without UPJ ulcers. These children were followed up for any development of ES and investigated for human herpesvirus 6 (HHV 6) as the causative agents of the febrile episodes. RESULTS: In this study, 20 out of 46 febrile children aged 3 months to 3 years with UPJ ulcers were virologically and/or serologically confirmed to be due to primary HHV 6 infection. The rest of the 26 children without ulcers did not have HHV 6 infection. Of the 20 children with UPJ ulcers, only 17 of the 19 children with adequate follow-up till subsidence of fever developed ES. None of the 26 children without UPJ ulcers developed ES. CONCLUSION: Statistically, there was a significant association of UPJ ulcers as an early sign of ES with a positive predictive value of 89.5% and negative predictive value of 100%. This finding also suggests that the presence of UPJ ulcers is a useful pathognomic clinical sign of symptomatic primary HHV 6 infection.

Antibodies, Viral↗
PubMed2000

Intracellular calcium antagonist protects cultured peritoneal macrophages against anthrax lethal toxin-induced cytotoxicity.

The lethal toxin of Bacillus anthracis is central to the pathogenesis of anthrax. Using primary cultures of mouse peritoneal macrophages, we have demonstrated that intracellular calcium release inhibitors protect against anthrax lethal toxin-induced cytotoxicity. The cytolytic effect of anthrax lethal toxin was markedly reduced by dantrolene, an inhibitor of calcium release from intracellular calcium stores. Pretreatment of macrophages with cyclosporin A, which has been shown to be a potent inhibitor of calcium release from mitochondria, also protected cells against cytotoxicity. These results indicate that calcium release from intracellular store may be an essential step for the propagation of anthrax lethal toxin-induced cell damage in macrophages. Thus our findings suggest that dantrolene, cyclosporin A, and possibly other drugs affecting intracellular calcium pools might be effectively preventing the toxicity from anthrax lethal toxin.

Animals↗
PubMed2000

Tuberculous cellulitis.

We report a case of cutaneous tuberculosis presenting as cellulitis. The patient was a 63-year-old Korean woman who also had diabetes mellitus and a 20-year-history of oral corticosteroid medication prescribed for arthralgia. In addition, she had had pulmonary tuberculosis 20-year previously for which she received systemic treatment for 1 year. Her clinical cellulitis failed to respond to antibiotic therapy. Subsequent investigations, using histopathology and polymerase chain reaction, established an alternative diagnosis of cutaneous tuberculosis. The skin eruption cleared after treatment with isoniazid, rifampicin, ethambutol and pyrazinamide. This case represents a most unusual presentation of tuberculosis in the skin. The atypical features may reflect the patient's general medical state.

Antitubercular Agents↗
PubMed2000

Analysis of the breath hydrogen test for carbohydrate malabsorption: validation of a pocket-sized breath test analyser.

OBJECTIVE: To assess the validity and clinical application of a hand-held breath hydrogen (H2) analyzer (BreatH2, Europa Scientific, Crewe, UK). METHODOLOGY: Breath samples of patients referred to the Gastroenterology Unit, Women's and Children's Hospital, North Adelaide, South Australia, for confirmation of the diagnosis of carbohydrate malabsorption were analysed with the Quintron microlyzer (Quintron Instrument Co., Milwaukee, USA) and the BreatH2 analyser, using the Quintron microlyzer as the gold standard. RESULTS: Twenty-nine breath H2 tests (BHT) were performed in 29 patients aged 2 months to 61 years. The sensitivity and specificity of the BreatH2 analyser in detecting a positive BHT using the Quintron microlyser as the gold standard were 0.90 and 0.95 with positive and negative predictive values of 0.90 and 0.95, respectively. There was one false positive and one false negative reading. Bland-Altman plots showed a high degree of agreement between the values obtained with two different methods. CONCLUSIONS: The diagnosis of carbohydrate malabsorption, using a portable breath H2 analyser (BreatH2), achieved an acceptable degree of sensitivity and specificity, enabling it to be used where no alternative is available.

Adolescent↗
PubMed2000

Extra-intestinal non-typhoidal Salmonella infections in children.

Extra-intestinal non-typhoidal Salmonella (NTS) infections are uncommon in developed countries but common in developing ones. The risk factors, clinical features and outcome of children admitted to the Department of Paediatrics, University of Malaya Medical Center, Kuala Lumpur from 1978 to 1998 with extra-intestinal NTS infections were reviewed. All positive cultures of NTS, blood, cerebrospinal fluid, urine, synovial, pericardial and other body secretions (except stools), were included. Of the 98 cases reviewed, 56 were boys and 42 girls. The mean age was 2.1 years (range: newborn to 14 years). Twenty-seven children were severely immunocompromised and 21 had underlying chronic medical disorders. Bacteraemia was the most commonly detected type of infection and meningitis the commonest focal infection. The overall mortality rate was 15%. An immunocompromised state or underlying chronic medical disorder was associated with increased mortality. The three serotypes most commonly isolated were S. enteritidis, S. paratyphi B and S. typhimurium. Most isolates were sensitive to antibiotics commonly used in salmonellosis.

Adolescent↗
PubMed2000

VEGF, fetal liver kinase-1, and permeability increase during unilateral lung ischemia.

Vascular endothelial growth factor (VEGF) is a potent mediator of increased vascular permeability and an endothelial cell mitogen. Because VEGF is upregulated during ventilated ischemia of isolated lungs and may lead to both increased vascular permeability and neovascularization, we hypothesized that VEGF and kinase insert domain-containing receptor/fetal liver kinase-1 (KDR/flk-1) expression would increase acutely after unilateral pulmonary arterial (PA) ischemia in vivo in association with evidence of endothelial cell barrier dysfunction. To test this hypothesis, VEGF and KDR/flk-1 mRNA and protein expression were measured after 4, 8, and 24 h of left PA ligation in mice. Permeability was assessed at the same time points by measurement of bronchoalveolar lavage protein concentration and lung wet-to-dry weight ratios. Results were compared with those from uninstrumented and sham-operated mice. VEGF and KDR/flk-1 protein in the left lung both increased by 4 h and then returned to baseline, whereas increased VEGF and KDR/flk-1 mRNA expression was sustained throughout 24 h of unilateral ischemia. Bronchoalveolar lavage protein concentration increased transiently during ischemia, whereas wet-to-dry weight ratio of the left lung increased more slowly and remained elevated after 24 h of left PA ligation. These results suggest that increased expression of VEGF and KDR/flk-1 during unilateral PA occlusion in mice may contribute to the development of acute lung injury in this model.

Animals↗
PubMed2000

Long-term regulation of urea transporter expression by vasopressin in Brattleboro rats.

Regulation of urea concentration in the renal medullary interstitium is important for maintenance of hypertonicity and therefore the osmotic driving force for water reabsorption. Studies in Sprague-Dawley rats showed that restriction of water intake for 3 days results in upregulation of urea transporter (UT) mRNA in the inner stripe of outer medulla of the kidney (2.9-kb UT2) but not in the inner medulla (4.0-kb UT1). The present study was performed to investigate the role of vasopressin in long-term regulation of UT1 and UT2 in neurogenic diabetes insipidus (Brattleboro) rats treated with a 7-day continuous infusion of [Arg(8)]-vasopressin (AVP), [deamino-Cys(1), D-Arg(8)]-vasopressin (dDAVP) or vehicle. Northern analysis showed that water restriction alone had no effect on the level of UT2 mRNA in vehicle-treated Brattleboro rats but UT2 mRNA markedly increased and UT1 mRNA modestly decreased after treatment with dDAVP. In situ hybridization further demonstrated that the UT2 signal is upregulated and spread along the descending thin limbs of loops of Henle and that UT1 signal is downregulated in the inner medullary collecting ducts in vasopressin-treated rats, with a greater response for dDAVP compared with the AVP-treated group. Immunocytochemistry studies revealed that the UT1 and UT2 proteins are also modified in the same pattern as the transcript changes. Our studies reveal the role of vasopressin in long-term regulation of UT1 and UT2 expression during water restriction.

Animals↗
PubMed2000

Microsurgical anatomy of the perigeniculate ganglion area as seen from a translabyrinthine approach.

Detailed anatomic knowledge of the microsurgical anatomy of the perigeniculate ganglion area is essential to probing adjacent to the facial nerve by a translabyrinthine approach. This study was designed to investigate the surgical anatomy of the perigeniculate ganglion area of the facial nerve from a translabyrinthine point of view. We dissected 15 human temporal bones under a microscope, measured the lengths of the tympanic segment and the labyrinthine segment by a middle cranial fossa approach, and measured the angle between the tympanic and labyrinthine segments by a translabyrinthine approach. The distance of the facial nerve from the cochleariform process to the geniculate ganglion was 3.8+/-0.7 mm. The length of the labyrinthine segment of the facial nerve was 4 +/-0.8 mm. The angle between the tympanic and labyrinthine segments from a translabyrinthine point of view was 26 degrees +/-5 degrees. Precise knowledge about the microsurgical anatomy of the perigeniculate ganglion area of the facial nerve from a translabyrinthine viewpoint is imperative for facial nerve decompression by a translabyrinthine approach.

Decompression, Surgical↗
PubMed2000

Involvement of protein kinase C-gamma in IL-1beta-induced cyclooxygenase-2 expression in human pulmonary epithelial cells.

The signaling pathway of protein kinase C (PKC) is known to play a role in mediating the action of various cytokines. Here we examined the signal transduction pathway of PKC activation and the role of PKC isoforms in interleukin-1beta (IL-1beta)-mediated cyclooxygenase-2 (COX-2) expression in human pulmonary epithelial cell line (A549). The tyrosine kinase inhibitors (genistein and tyrphostin AG126) and phosphatidylcholine-phospholipase C inhibitor (D-609) prevented IL-1beta-induced prostaglandin E(2) (PGE(2)) release and COX-2 expression, whereas U-73122 (a phosphatidylinositol-phospholipase C inhibitor) and propranolol (a phosphatidate phosphohydrolase inhibitor) had no effect. The PKC inhibitors (Go 6976 and Ro 31-8220) and NF-kappaB inhibitor, pyrrolidine dithiocarbamate, also attenuated IL-1beta-induced PGE(2) release and COX-2 expression. Western blot analysis using PKC isoenzyme-specific antibodies indicated that A549 cells expressed PKC-alpha, -gamma, -iota, -lambda, -zeta, and -micro. IL-1beta caused the translocation of PKC-gamma but not other isoforms from cytosol to the membrane fraction. Moreover, the translocation of PKC-gamma was inhibited by genistein or D-609, but not by U-73122. IL-1beta caused the translocation of p65 NF-kappaB from cytosol to the nucleus as well as the degradation of IkappaB-alpha in cytosol. Furthermore, the translocation of p65 NF-kappaB was inhibited by genistein, Go 6976, Ro 31-8220, or pyrrolidine dithiocarbamate. These results indicate that in human pulmonary epithelial cells, IL-1beta might activate phosphatidylcholine-phospholipase C through an upstream tyrosine phosphorylation to elicit PKC activation, which in turn initiates NF-kappaB activation, and finally induces COX-2 expression and PGE(2) release. Of the PKC isoforms present in A549 cells, only activation of PKC-gamma is involved in regulating IL-1beta-induced responses.

Cyclooxygenase 2↗
PubMed1999

Glutamate-induced rise in cytosolic calcium concentration stimulates in vitro rates of juvenile hormone biosynthesis in corpus allatum of Diploptera punctata.

We show that in a cockroach, Diploptera punctata, endocrine function of the corpus allatum may be modulated by L-glutamate, a major fast excitatory neurotransmitter in the central nervous system of vertebrates and invertebrates. The widely accepted concept that synthesis of juvenile hormone (JH) depends upon intracellular calcium concentration, is extended by the finding that 60 and 100 microM L-glutamate induces both an increase in calcium concentration in the cytosol of corpus allatum cells, and stimulates JH synthesis in vitro. We show that L-glutamate stimulates JH synthesis by inducing calcium influx since in calcium-free medium the stimulatory effect is not observed. Furthermore, the non-specific glutamate-receptor antagonist, 100 microM kynurenate, and 1.8 mM magnesium, inhibit the stimulatory effect of L-glutamate on JH synthesis in vitro. These results suggest that functional ionotropic glutamate receptors are present on the surface of the cells in corpus allatum, and that rates of JH are at least in part regulated via these receptors.

Animals↗
PubMed1999

SKP-450 inhibits migration and DNA synthesis stimulated by oxidized low density lipoprotein in smooth muscle cells.

This study was carried out to examine the inhibitory effects of SKP-450 (2-[2"(1", 3"-dioxolone)-2-methyl]-4-(2'-oxo-1'-pyrrolidinyl)-6-nitro-2H-1-be nzo pyran), a potassium channel opener, on the proliferation and migration stimulated by oxidized low density lipoprotein (LDL) of cultured smooth muscle cells of Wistar Kyoto rat aorta. SKP-450 (10(-7) and 10(-6) M) as well as probucol (10(-7)-10(-5) M) reduced the production of thiobarbituric acid reactive substances from LDL submitted to CuSO(4) (10 microM). The increased [3H]thymidine incorporation and migration (chemotactic and wound-edge) of the cultured smooth muscle cells in association with increased production of platelet-derived growth factor (PDGF)-BB-like immunoreactivity stimulated by oxidized LDL were significantly reduced by SKP-450 (10(-7)-10(-6) M). Inhibition by SKP-450 of the oxidized LDL-stimulated [3H]thymidine incorporation was antagonized by iberiotoxin (10(-7) M), but not by glibenclamide (10(-6) M), suggestive of mediation of Ca(2+)-activated K(+) channel opening in the action of SKP-450. Taken together, SKP-450 inhibited the proliferation and migration of the smooth muscle cells as well as PDGF production stimulated by oxidized LDL, accompanying with its antiperoxidative action.

Animals↗
PubMed1999

Synthesis of four diastereomeric 3,5-dialkoxy-2,4-dimethylalkanals by a simple extension of the non-aldol aldol process to bis(propionates).

[formula: see text] The synthesis of all four diastereomers of bis(propionates), 3,5-dialkoxy-2,4-dimethylalkanals, by non-aldol aldol chemistry is described. The epoxy alcohols (3, 4) were converted into the mesylates (9, 11) which were cleanly rearranged to the desired 3,5-bis(oxygenated)-2,4-dimethylalkanals (10, 12) in high yield. The epoxy mesylates (13, 16) gave the desired products (14, 17) in good yield on treatment with TMSOTf and a hindered base.

Aldehydes↗
PubMed1999

Peribulbar innervation and substance P expression following nonpermanent injury to the human scalp hair follicle.

The hair pluck procedure alters the anatomy of the anagen hair bulb. Hemorrhage can occur in the mesenchymal sheath and breaks at the proximal epithelium, above or around the upper third of the dermal papilla, have been reported. We hypothesized that innervation, as identified with protein gene product 9.5 (PGP 9.5), and expression of the neuropeptide Substance P (SP) within the dermal papilla would also be altered following plucking. We focused on studying SP as this neuropeptide has been associated with several cellular responses, including anagen hair growth in the C57BL/6 mouse model. Four millimeter punch biopsies were obtained from the occipital scalp of two healthy adults. Hair was then plucked and additional biopsies were obtained immediately, and at 1 d, 1 wk, and 1 mo after plucking. Each set was processed for immunohistochemical analyses and in-focus optical sections of the dermal papilla were captured by laser scanning confocal microscopy and later reconstructed into single images. Following injury, SP was expressed in a disorganized pattern below the dermal papilla. There was also a significant reduction in labeled neuronal cells, and SP expression was enhanced within peribulbar blood vessels at 1 d and 1 wk. By 1 mo, peribulbar nerves, vessels, and SP expression were similar to baseline observations. It remains to be ascertained whether PGP 9.5, also known as unbiquitin hydrolase, and SP are involved in the proliferation of new matrix cells in the human scalp hair follicle following injury.

Adult↗
PubMed1999

Nurse's cap alopecia.

BACKGROUND: Traction alopecia associated with the nurse's cap is a relatively common form of occupational hair loss. METHODS: We examined 199 healthy South Korean nurses to assess the clinical and pathologic characteristics of traction alopecia caused by prolonged traction exerted at the point of attachment of the nurse's cap. RESULTS: Seven nurses (3.5% of 199) had hair loss at the pin site used to secure the nurse's cap. The lesions were exclusively localized on the parieto-occipital scalp. Histopathologic findings revealed characteristic cicatricial changes which showed a marked decrease in the number of hair follicles without inflammation. CONCLUSIONS: Nurse's cap alopecia is not an uncommon occupational alopecia, and appears to be a distinct clinical entity which should be distinguished from other forms of patchy alopecia.

Adult↗
PubMed1999

Seroprevalence of Helicobacter pylori infection in Malaysian children: evidence for ethnic differences in childhood.

OBJECTIVES: To determine the prevalence of Helicobacter pylori (H. pylori) in healthy Malaysian children and to discover whether differences exist among children of different races. METHODS: Serum samples from asymptomatic children tested for H. pylori seropositivity using an ELISA test. RESULTS: Five hundred and fourteen healthy urban Malaysian children aged 0.5 to 17 (mean 5.9) years from three different racial groups had their blood tested for H. pylori antibodies. The overall prevalence was 10.3%. There was no significant difference in the prevalence of infection between boys and girls, but a significant rise was noted with increasing age (P = 0.009). Seropositivity was most common in the Indians and lowest in the Malays (P = 0.001). Father's level of education did not affect the child's rate of H. pylori seropositivity. CONCLUSION: The prevalence of H. pylori seropositivity among asymptomatic urban Malaysian children is lowest in Malays. Intermediate in Chinese and highest in Indians. The racial differences found in children are consistent with those found in Malaysian adults.

Adolescent↗