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Biomedical subjects

S Lee

Publications and source records attributed to S Lee.

At least 865 records · Page 48Linked to original sources
PubMed1996

Polymerase chain reaction reveals herpes simplex virus DNA in saliva of patients with Behçet's disease.

The etiology of Behçet's disease is unclear, but viral infection is thought to be one etiologic factor. The aims of this study were to detect herpes simplex virus (HSV) DNA in the saliva of patients with Behçet's disease and of healthy persons, to determine whether the presence of HSV in saliva is associated with the presence of intraoral ulcer, and to investigate the relationship between HSV and Behçet's disease. The polymerase chain reaction (PCR) was used to detect HSV DNA sequences in DNA extracted from the saliva of patients with Behçet's disease and of healthy control subjects. Of 66 patients with Behçet's disease diagnosed clinically, 19 were diagnosed as complete type, 29 as incomplete type and 18 as suspected type. Of 66 DNA preparations from the saliva of the patients, 26 (39.4%) showed the 289-bp band. This contrasts with 12 of 87 preparations (13.8%) from healthy controls (P < 0.01). There were no significant differences among the three patient groups. All the 289-bp bands analyzed by restriction endonuclease digestion yielded the expected 158-bp and 131-bp fragments when digested with PstI.HSV DNA was detected in 12 of 33 Behçet's disease patients (36.4%) with oral ulceration and 14 of 33 patients (42.4%) without oral ulceration at the time of testing. There was no statistically significant correlation in the PCR results between the two groups.

Base Sequence↗
PubMed1996

Expression of neuronal-NOS in developing basal forebrain cholinergic neurons: regulation by NGF.

Nerve growth factor (NGF) acts through the receptor tyrosine kinase trkA to serve as a trophic factor for cholinergic neurons in the medial septal nucleus and vertical limb of the diagonal band. We have previously shown that the neuronal isoform of nitric oxide synthase (NOS) is selectively expressed in a large fraction of trkA-expressing cholinergic neurons in these brain regions in the adult rat, and that NGF induces the expression of neuronal-NOS in these cells. Herein, we show that: 1) neuronal-NOS is also localized to these neurons in the developing septum; 2) the expression of neuronal-NOS is regulated in the developing medial septal nucleus and vertical limb of the diagonal band; 3) neuronal-NOS regulation parallels that for other markers of basal forebrain cholinergic neuron differentiation, such as cholineacetyltransferase; and 4) NGF infusion in the postnatal period induces robust increases in neuronal-NOS mRNA and in NOS activity in the basal forebrain. Taken together with earlier findings, our results suggest that neuronal-NOS has a role in the differentiation and mature function of septal cholinergic neurons. Through enhancing neuronal-NOS synthesis, endogenous NGF is likely to regulate NO functions in vivo.

Acetylcholinesterase↗
PubMed1996

Characterization of K+ channels in the basolateral membrane of rat tracheal epithelia.

To study K+ channels in the basolateral membrane of chloride-secreting epithelia, rat tracheal epithelial monolayers were cultured on permeable filters and mounted into an Ussing chamber system. The mucosal membrane was permeabilized with nystatin (180 microg/ml) in the symmetrical high K+ (145 mm) Ringer solution. During measurement of the macroscopic K+ conductance properties of the basolateral membrane under a transepithelial voltage clamp, we detected at least two types of K+ currents: one is an inwardly rectifying K+ current and the other is a slowly activating outwardly rectifying K+ current. The inwardly rectifying K+ current is inhibited by Ba2+. The slowly activating K+ current was potentiated by cAMP and inhibited by clofilium, phorbol 12-myristate 13-acetate (PMA) and lowering temperature. This is consistent with the biophysical characteristics of ISK channel. RT-PCR analysis revealed the presence of ISK cDNA in the rat trachea epithelia. Although 0.1 mM Ba2+ only had minimal affect on short-circuit current (Isc) induced by cAMP in intact epithelia, 0.1 mM clofilium strongly inhibited it. These results indicate that ISK might be important for maintaining cAMP-induced chloride secretion in the rat trachea epithelia.

Animals↗
PubMed1996

Myxoma of the mandible.

Myxoma of the jaw bone is a peculiar and rare tumor. A case of myxoma of the mandible is described in a 38-year-old man. The plain X-ray showed multiple osteolytic destructive lesions in the molar root area. CT scans demonstrated osteolytic expansile lesions with mild enhancement of the solid portion of the mass. Histologically, the tumor is composed of plump stellate cells with abundant amorphous myxoid stroma.

Adult↗
PubMed1996

dsRNA associated with virus-like particles in Eimeria spp. of the domestic fowl.

RNA segments, identified as double-stranded, were found in sporozoites of the Guelph strains of Eimeria acervulina, E. brunetti, E. maxima and E. necatrix and in 8 of 11 strains of E. acervulina obtained from poultry houses across the United States. These RNAs were resistant to RNase A digestion in the presence of high salt concentrations (0.3 M NaCl). On agarose-gel electrophoresis, E. acervulina had one obvious band at 1.7 kb and a faint band at 3.5 kb; E. brunetti had two bands at 2.1 and 3.3 kb, respectively; E. maxima had one band at 4.5 kb; and E. necatrix had two major bands at 4.5 and 5.6 kb, respectively. No dsRNA band was seen in the three strains of E. tenella examined. Virus-like particles were purified by cesium chloride density centrifugation of homogenates of E. necatrix sporulated oocysts. The fraction at peak virus concentration had a buoyant density of 1.39 g ml-1. These virus-like particles were icosahedral, had no envelope and measured 42-44 nm in diameter. Only one RNA band at 5.6 kb was observed when nucleic acids from gradient fractions containing virus were subjected to electrophoresis. The 4.5-kb dsRNA segment of E. necatrix was not associated with a virus-like particle.

Animals↗
PubMed1996

Infrequent microsatellite instability during the evolution of myelodysplastic syndrome to acute myelocytic leukemia.

Microsatellites are highly polymorphic, short-tandem repeat sequences dispersed throughout the genome. Instability of these repeat sequences at multiple gentic loci may result from mismatch repair errors and occur in hereditary nonpolyposis colorectal cancer and several other sporadic cancers, including chronic myelocytic leukemia as it progresses to blastic crisis. We investigated whether genetic instability occurred as myelodysplasia progressed to acute myelocytic leukemia. To this end, we studied microsatellite instability in 20 patients with myelodysplastic syndrome (MDS). These included five patients with refractory anemia (RA), three with refractory anemia with ringed sideroblast (RARS), nine with refractory anemia with excess blasts (RAEB) and three with chronic myelomonocytic leukemia (CMML). All of these patients transformed to acute myelocytic leukemia (AML) of various subtypes: three patients with M1, 11 with M2 and six patients with M4 (according to FAB classification). The DNA from both the MDS and AML phases of their disease was analyzed at 16 loci, and only four microsatellite instabilities were found in the 240 paired samples (1.6%) analyzed. These results indicate that mismatch repair errors such as microsatellite instability are not important in the evolution of MDS to AML.

Adult↗
PubMed1996

Reconsidering the status of anorexia nervosa as a western culture-bound syndrome.

Based on Ritenbaugh's 1982 definition, this essay reconsiders the status of anorexia nervosa as a Western culture-bound syndrome (CBS). It argues that anorexia nervosa, in its culturally reconstructed fat phobic form, is no longer bound to specific Western localities. Instead, it may be conceived as being grounded in the transnational culture of 'modernity', characterized by an internationalised socio-economic stratum now found in many rapidly urbanising parts of the world, and composed of increased affluence, as well as the globalization of fat phobia and diffusion of biomedical technology. Although the treatment implication of Ritenbaugh's CBS concept may appear to be misplaced from the clinician's pragmatic perspective, its salience for clarifying the interaction of individual and cultural concerns in self-starvation, as well as for fostering a needed self-scrutiny in psychiatry, is affirmed. A critique of the dialectical relationship between culture and psychopathology is then put forward. This addresses the apparently conflicting role of anorexia nervosa in enacting as well as combating the cultural pursuit of thinness, and ends by highlighting the inadvertent influence of the biomedical establishment in propagating the condition with measures intended, ironically, for preventing it.

Acculturation↗
PubMed1996

Gender differences in the effect of prenatal alcohol exposure on the hypothalamic-pituitary-adrenal axis response to immune signals.

Immature (3 week old) rat offspring of alcohol (E)-fed dams show a blunted ACTH response to immune signals such as interleukin-1 beta (IL-1 beta) and endotoxin (LPS). In contrast, mature offspring respond to physical stresses with an exaggerated activation of their hypothalamic-pituitary-adrenal (HPA) axis. The present work was aimed at determining if there was a differential influence of prenatal E exposure on the HPA axis responses to various stressors or if, alternatively, sexual maturation modified these responses. When administered IL-1 beta at 5 weeks age, E-treated intact male offspring released less ACTH, compared to control (C) or pair-fed (PF) animals. However, they showed an augmented response to LPS and a local inflammatory process induced by turpentine injection. At this same age, intact E females secreted significantly more ACTH in response to IL-1 beta, LPS and turpentine, than C or PF offspring. By 9 weeks of age, both E males and E females exhibited larger (p < .05) ACTH responses to all three immune stimuli. In order to determine whether sex steroids modulate the influence of E in females, ovariectomy was done prior to puberty. This treatment decreased the difference in the ACTH released by E and C rats in response to IL-1 beta, LPS and turpentine. These results show that while immature rats exposed to E prenatally released less ACTH in response to cytokines than C or PF animals did, this response was qualitatively reversed after puberty. At that time, the larger amounts of ACTH secreted by E offspring, compared to the other groups, were reminiscent of the hyperactive response of the HPA axis when these offspring were exposed to physical stress. Interestingly, removal of circulating ovarian steroids prevented the influence of E from being exerted. This suggests the presence of a functional relationship between the pathways influenced by prenatal E and those influenced by female sex steroids, that are important in regulating the activity of the HPA axis.

Acute-Phase Reaction↗
PubMed1996

Prenatal diagnosis of Kell blood group genotypes: KEL1 and KEL2.

OBJECTIVE: Our purpose was to devise diagnostic test(s) that determine fetal KEL1 and KEL2 genotypes. STUDY DESIGN: KEL1 and KEL2 polymorphisms are due to a single C to T base substitution at nucleotide 698 of exon 6 of KEL. This allowed us to develop two polymerase chain reaction tests that distinguish KEL1/1 and KEL2/2 homozygotes and KEL1/2 heterozygotes. The first test uses a Bsm I restriction fragment length polymorphism in a genomic deoxyribonucleic acid polymerase chain reaction product containing the single base polymorphism, and the second test uses allele-specific primers to distinguish KEL1 and KEL2 genotypes. These tests were applied in a blind study to 15 amniotic fluid deoxyribonucleic acid samples. The corresponding KEL1 and KEL2 fetal red blood cell phenotypes were determined serologically. The tests were also applied to two families in which the mothers had antibodies to KEL1. RESULTS: In all cases results of analysis of Kell genotypes from the amniotic fluid deoxyribonucleic acid samples agreed with the fetal red blood cell Kell phenotypes. The tests were also successfully used to determine fetal Kell genotype by use of peripheral blood deoxyribonucleic acid. CONCLUSION: Two polymerase chain reaction-based tests can be used for prenatal diagnosis of KEL1 and KEL2 genotypes; these procedures should prove useful in the proper management of Kell-sensitized pregnancies.

Amniotic Fluid↗
PubMed1996

Alteration of cell membrane by stress waves in vitro.

Experiments on the biological effects of laser-induced stress waves indicate that there is a transient increase in the permeability of the cell membrane. A cell viability assay (propidium iodide exclusion) shows that mouse breast sarcoma cells are viable after a stress wave. The kinetics of this transient membrane permeability are measured using time-resolved fluorescence imaging. The efflux of a membrane-impermeable fluorescent probe (calcein) following the application of a 300-bar stress wave implies that there is an increase in the membrane permeability. This efflux ceases within 80 s after a stress wave, suggesting that the membrane is no longer permeable to the fluorescent probe. Fitting the observed kinetics to a simple diffusion model yields an average initial diffusion constant of 2.2 +/- 1.3 x 10(-7) cm2/s for mouse breast sarcoma cells following the application of a laser-induced stress wave.

Animals↗
PubMed1996

Expression of Fas antigen in acute myeloid leukaemia is associated with therapeutic response to chemotherapy.

Flow cytometric immunofluorescent analysis was used to assess Fas antigen (CD95) expression in blasts obtained from the bone marrow of 30 patients with acute myeloid leukaemia. The percentage of positive cells in each sample was highly variable. Fas antigen expression did not correlate with age, FAB subtype, white blood cell counts, or CD34 expression. Low expression of Fas was associated with a low complete remission rate after induction chemotherapy (62.5% in cases with < 20% positive cells v 92.9% in cases with > or = 20% positive cells, P < 0.01). The main cause for not achieving remission was resistant disease. Our results suggest that the quantitation of Fas expression can be predictive of treatment outcome in acute myeloid leukaemia.

Acute Disease↗
PubMed1996

Bone mass and metabolism in women aged 45-55.

OBJECTIVE: Changes in calcium homeostasis and bone mass around the climacteric are poorly understood. We examined relations between endocrine factors and indices of bone mass and metabolism in healthy women approaching the menopause. DESIGN: Cross-section study. PATIENTS: Sixty-eight spontaneously menstruating women aged 45-55. MEASUREMENTS: Bone density measured at lumbar spine (LS) and femoral neck (FN) using dual energy X-ray absorptiometry and distal non-dominant forearm using peripheral quantitative computed tomography. We recorded menstrual history, physical activity and dietary calcium, and measured serum calcium, phosphate, alkaline phosphatase, osteocalcin, vitamin D, fT3, T4, TSH, PTH, FSH and oestradiol (E2), and urinary pyridinoline (PYD) and deoxypyridinoline (DPD) excretion. RESULTS: Using serum FSH level as a marker of ovarian function, 63 subjects could be classified into one of three groups: group A (serum FSH < 10 U/l, n = 29), group B (10-35 U/l, n = 27) and group C (> 35 U/l, n = 7). Bone density fell with declining ovarian function at the LS, FN and forearm trabecular (but not cortical) sites. Serum PTH was lower in group A vs B (mean (SD) 2.68 (0.97) vs 3.52 (1.17) pmol/l, P < 0.05), but similar to group C (2.90 (1.09) pmol/l, P = NS). Serum phosphate was elevated in group C compared to groups A and B (1.17 (0.15) vs 1.04 (0.11) and 1.05 (0.13) mmol/l, P < 0.05), and urinary PYD (61.1 (8.0) vs 50.4 (11.6) and 43.9 (8.1) mumol/mol creatinine) and DPD (15.9 (3.9) vs 12.0 (3.6) and 11.4 (3.6) mumol/mol creatinine) excretion were also increased. There were no significant differences in vitamin D metabolites or osteocalcin. Multivariate analysis suggested serum osteocalcin was positively related to physical activity and serum 1,25-dihydroxycholecalciferol levels. Serum free T3 was positively correlated with urinary DPD excretion, and inversely related to serum PTH. In all subjects, serum PTH was related to body weight (r = 0.38, P = 0.002). CONCLUSIONS: Declining ovarian function before menopause is accompanied by reductions in bone mass and altered calcium metabolism. Free T3 may regulate bone resorption and indirectly modulate PTH release.

Amino Acids↗
PubMed1996

Point mutations characterize KEL10, the KEL3, KEL4, and KEL21 alleles, and the KEL17 and KEL11 alleles.

BACKGROUND: The Kell blood group system is complex, consisting of five sets of alleles and expressing high- and low-incidence antigens and at least 11 other independently expressed antigens. The molecular basis of two sets of alleles: KEL1 (K) and KEL2 (k) and KEL6 (Jsa) and KEL7 (Jsb) have been elucidated as single-base mutations leading to amino acid changes. The molecular basis for the KEL3 (Kpa), KEL4 (Kpb), and KEL21 (Kpc) alleles, the KEL11(Cote) and KEL17(Wka) alleles, and for KEL10 (UIa) is now reported. STUDY DESIGN AND METHODS: Genomic DNA from unrelated individuals with KEL:3,-4,-21 [Kp(a+b-c-)], KEL:-3,-4,21 [Kp(a-b-c+)], KEL:17,-11, and KEL:10 (UIa) phenotypes was amplified by polymerase chain reaction (PCR) with primers for the 19 exons of KEL. The PCR products were sequenced and compared to the DNA sequences of a common Kell system phenotype, KEL:-3,4,-21,-17,-10. Base mutations found were confirmed by restriction fragment length polymorphism analysis in which DNA of unrelated persons with similar red cell phenotypes was used. RESULTS: In all cases, single-base mutations were responsible for the expression of the various antigens. In KEL3 (Kpa), KEL4 (Kpb), and KEL21 (Kpc), point mutations at the same codon in exon 8, encoding amino acid residue 281, distinguish the three genes. KEL4 has the CGG codon for arginine, KEL3 has the TGG codon for tryptophan, and KEL21 has the CAG codon for glutamine. KEL17 has a T1025C mutation in exon 8, encoding a valine-to-alanine amino acid change at residue 302. KEL10 has an A1601T mutation in exon 13, encoding a glutamic acid-to-valine change at residue 494. In all cases, the point mutations created restriction enzyme sites, and PCR-based restriction fragment length polymorphisms confirmed that these point mutations occurred in unrelated persons with the same red cell phenotype. CONCLUSION: Single-base substitutions characterize the KEL3, KEL21, KEL17, and KEL10 genes. The allelic relationship of KEL3, KEL4, and KEL21 was confirmed because the mutations occur in the same codon, expressing different amino acids. PCR-based restriction fragment length polymorphisms can be used to distinguish genotypes.

Alanine↗
PubMed1996

Threshold for radiation-related severe mental retardation in prenatally exposed A-bomb survivors: a re-analysis.

Significant effects on the developing human brain of exposure to ionizing radiation are seen among individuals exposed in the 8th-25th week after ovulation. These effects, particularly in the highly vulnerable period of 8-15 weeks after ovulation, manifest themselves most dramatically as an increased frequency of severe mental retardation. However, the distribution of cases of severe mental retardation suggests a threshold in the low-dose region. The 95% lower bound of the threshold in those survivors exposed 8-15 weeks after ovulation was zero for the individual data based on the simple linear model, and 0.15 Gy based on the exponential linear model used in our previous report (1987), but the 95% lower bound of the threshold based on all of the data including 21 additional cases with known doses appears to be 0.05 Gy using the maximum likelihood estimates derived from an exponential-linear model. The latter model was selected because it provides the best fit from the standpoint of the stableness and reasonableness of the estimates among the five models applied to the data. When two probably non-radiation-related cases of Down's syndrome are excluded from the 19 mentally retarded cases exposed 8-15 weeks post ovulation, the 95% lower bound of the threshold is in the range of 0.15-0.25 Gy based on the exponential-linear model used in 1987, but is in the range of 0.06-0.31 Gy when the more reasonable and better model applied here is used. For exposure in the 16-25-week period based on the same model, the 95% lower bound of the threshold changed from 0.25 to 0.28 Gy, both with and without inclusion of the two probable non-radiation-related mentally retarded cases; one of these cases was probably familial in origin since there was a retarded sibling, and the other due to infection, since the individual had Japanese B encephalitis at age 4 years.

Brain↗
PubMed1996

Risk factors for fungemia in children infected with human immunodeficiency virus: a case-control study.

To define the risk factors related to the occurrence of fungemia in children infected with human immunodeficiency virus (HIV), we performed a matched case-control study. During a 6-year period (1987-1993), fungemia developed in 22 (6.3%) of 347 HIV-infected children observed at the Pediatric Branch of the National Cancer Institute. Each of these 22 cases was matched by age and gender with three controls. Multiple logistic regression indicated that the best predictor of fungemia in this population was the presence of a central venous catheter placed for > 90 days (P < .00001), followed by a group of risk factors composed of 10 independent variables adjusted for a CD4 cell count of < 100/MicroL (P < .045). Those variables included treatment with more than three antibiotics, treatment with more than three parenteral antibiotics, > 30 days of antibiotic treatment, bacterial infections, > 30 days in the hospital, hypoalbuminemia, C3 (Centers for Disease Control and Prevention) classification of HIV infection, and malnourishment. We conclude that prolonged placement of central venous catheters is the most important risk factors for fungemia in HIV-infected children and that the risk of fungemia is further influenced by antibacterial therapy, catheter manipulation, and host response.

Adolescent↗
PubMed1996

Analysis of live, oral poliovirus vaccine monopools for human immunodeficiency virus type 1 and simian immunodeficiency virus.

Although there is no evidence for transmission of mammalian retroviruses to humans via vaccine immunization, the allegations of contamination of oral poliovirus vaccines with human immunodeficiency virus (HIV) type 1 or a hypothetical progenitor virus from monkeys has created controversy and dispute regarding the origin of AIDS in humans. Twelve monovalent lots of live, attenuated oral poliovirus vaccine types 1, 2, and 3, which were released for use by a North American manufacturer between 1976-1989, were tested for the presence of HIV-1 and simian immunodeficiency virus (SIV). HIV/SIV were not detected in these monovalent poliovirus vaccine lots with the reverse transcriptase assay, a general detection assay, and highly sensitive and specific polymerase chain reaction assays.

Animals↗
PubMed1996

Peripheral course of genioglossal motor axons within the hypoglossal nerve of the rat.

The spatial compartmentalization of motor axons in cranial nerves has not been previously demonstrated. In the present study, motor axons in the medial lingual ramus of the hypoglossal nerve of rats were labeled using horseradish peroxidase and diaminobenzidine staining methods. Neuronal axons were segregated into fascicles within the main nerve trunk (average total length: 10.4 mm). Light microscopic examination of stained nerve sections revealed reaction product within individual axons and showed that the grouping of labeled nerve fibers in the medial ramus was maintained for at least the peripheral half of the nerve before the stain faded. The authors propose that the fascicular anatomy of the rat hypoglossal cranial nerve resembles that of peripheral spinal nerves in humans. This functional and structural compartmentalization may have a clinical impact on the repair and treatment of cranial nerve pathologies.

Animals↗