Biomedical subjects

Y L Lee

Publications and source records attributed to Y L Lee.

At least 55 records · Page 3Linked to original sources

PubMed1999

Deep vein thrombosis in elderly Hong Kong Chinese with hip fractures detected with compression ultrasound and Doppler imaging: incidence and effect of low molecular weight heparin.

Seventy-eight patients of average age 78 years suffering from an unilateral non-pathological hip fracture underwent compression ultrasound and pulsed and colour Doppler examination of both legs. Twenty-three patients were randomly placed on low molecular weight heparin (LMWH). Twenty-nine (37%) suffered deep venous thrombosis (DVT). There was no statistically significant difference in the incidence of DVT between the control and LMWH groups, and the incidence of DVT in elderly Chinese patients after hip replacement for a hip fracture is similar to that in other studies in Caucasians. There were, however, some differences, namely the contiguous nature of the thrombi rather than focal segmental clots, and the absence of propagation or tail formation. Although the numbers are small, this could possibly represent a population difference. There was a significantly increased occurrence of DVTs on the operated side in both groups. Serial ultrasound examination supports evidence that DVTs occur in the 1st week postoperatively, but there were also a number of patients who developed DVTs in the 2nd week. There was no statistically significant difference in overall incidence of DVT between patients on prophylactic heparin and the control group. Patients on prophylactic heparin had no thigh DVTs in comparison to the control group. LMWH may thus be effective in preventing thigh DVTs and pulmonary emboli.

Aged↗

PubMed1999

Effects of intrapancreatic neuronal activation on cholecystokinin-induced exocrine secretion of isolated perfused rat pancreas.

The role of intrapancreatic neurons in the action of cholecystokinin (CCK) on pancreatic exocrine secretion of the totally isolated, perfused rat pancreas was investigated. Intrapancreatic neurons were activated by applying electrical field stimulation (EFS) to the isolated pancreas for 45 min. When applying EFS, spontaneous pancreatic secretions of fluid and amylase increased until the second 15-min period of EFS and then decreased during the third 15-min period. Atropine (2 microM) notably reduced the EFS-evoked pancreatic secretions of fluid and amylase. The CCK-induced (10 pM) pancreatic secretions of fluid and amylase elevated further in the first 15-min period of EFS and then gradually resumed to the levels observed during application of CCK alone in the third 15-min period of EFS. However, the CCK-induced pancreatic secretions remained elevated even in the third 15-min period of EFS when an action of endogenous somatostatin was inhibited by cyclo-(7-aminoheptanonyl-Phe-d-Trp-Lys-Thr[BZL]) (10 nM) or pertussis toxin (200 ng/ml). EFS further elevated spontaneous exocrine secretion by the cysteamine-treated (300 mg/kg) pancreas, but this was markedly reduced, to normal levels, by infusing somatostatin (100 pM). EFS increased the numbers of immunoreactive somatostatin cells in the Langerhans' islets. The results indicate that intrapancreatic neuronal activation influences CCK-induced pancreatic secretions in a dual-phase pattern in the rat: an increase during the early phase and a decrease during the late phase. Endogenous somatostatin released from the islets appears to inhibit the enhancing effect of neuronal activation on CCK-induced pancreatic secretion. Of the intrapancreatic neurons, the cholinergic ones appear to predominate in EFS's effects on CCK-induced pancreatic secretion.

Amylases↗

PubMed1999

Percutaneous vertebral biopsy through intact bone: a coaxial bone transgressing technique with 18 gauge needle.

Advancement of radiologic technologies allows the detection of vertebral lesions at an earlier stage, thereby increasing the proportion of vertebral lesions that are surrounded by intact bone when they are detected. While biopsy guns are effective in obtaining good-quality tissue samples of osteolytic bone lesions, lesions that are covered by intact bone are not accessible with a biopsy gun. For percutaneous biopsy of osteolytic vertebral lesions, an intact-bone transgressing technique is described in which a simple, inexpensive and small-calibre (18-gauge) instrument is used to allow multiple passage of 20-gauge biopsy guns for effective tissue sampling. In this series consisting of metastatic and myeloproliferative lesions, the effectiveness and safety of this well-tolerated technique are demonstrated in thoracic and lumbar vertebrae.

Biopsy, Needle↗

PubMed1999

Enhanced cytotoxicity and suppression of glucose transport rate by combined treatment of recombinant human tumour necrosis factor-alpha and hyperthermia on L929 cells.

Combined treatment with human recombinant TNF-alpha (rhTNF-alpha) and hyperthermia at 43 degrees C arrested the growth of mouse fibrosarcoma L929 cells in vitro. The cytotoxic effect was enhanced in combined treatment compared with that following administration of rhTNF-alpha or hyperthermia alone. When the cells were subjected to hyperthermia at 43 degrees C for 3 hours and then incubated with 0.4 ng/ml rhTNF-alpha at 37 degrees C for 24 hours, a statistically significant 65% decrease in the rate of cellular glucose uptake was observed. This suppressive effect was synergistic in terms of effect achieved by rhTNF-alpha or hyperthermia individually. Since the growth of tumour cells depends mainly on catabolism of glucose, our findings indicate that one manner by which combined rhTNF-alpha and hyperthermia treatment inhibits L929 cell growth may be by reducing the supply of glucose to the cells.

Animals↗

PubMed1999

Inhibition of glucose uptake and suppression of glucose transporter 1 mRNA expression in L929 cells by tumour necrosis factor-alpha.

Recombinant human tumour necrosis factor-alpha (rhTNF-alpha) arrested the growth and suppressed glucose uptake of mouse fibrosarcoma L929 cells in vitro. When the cells were treated with rhTNF-alpha for 24 hours, the mRNA level of glucose transporter 1 (GLUT 1), which is the only GLUT found to be present in L929 cells in our study, was suppressed in a dose-dependent manner. Since the growth of tumour cells depends mainly on glucose catabolism, our findings may indicate that rhTNF-alpha inhibits L929 cells growth by lowering the glucose transport through suppression of GLUT 1 mRNA expression in the cells.

Animals↗

PubMed1999

Culture positive tuberculous meningitis: clinical indicators of poor prognosis.

Few studies have evaluated culture positive tuberculous meningitis (TBM) as a group. We evaluated certain clinical factors in culture positive TBM which could be associated with a poorer outcome. Out of 40 consecutive TBM patients seen over a period of 4 years in a tertiary referral hospital, 18 culture positive and non-human immunodeficiency virus (HIV) related cases were studied. The mean age was 37.9 +/- 14.9 years (range 9-63); five were males and 13 females. None had any associated active chronic medical illness. Patients (44.4%) started on antituberculous treatment within 24 h of admission. Treatment was initiated at a median time of 48 h upon admission in hospital. Univariate analysis revealed a significant correlation between hydrocephalus (P = 0.007) and poor morbidity and mortality. The other clinical factors were not statistically significant: age (P = 0.36): sex (P = 0.49); symptom duration (P = 0.69); BCG vaccination (P = 0.65); cerebral infarct (P = 0.63); extrameningeal spread (P = 1.00); steroids (P = 1.00); time to treatment (P = 0.94) and stage of disease (P = 0.11). Hydrocephalus was the only significant factor predisposing culture positive TBM patients to a poorer outcome. There was also a trend towards a poorer prognosis in those with advanced stage of the disease.

Adolescent↗

PubMed1999

Administration of interleukin-12 prevents mite Der p 1 allergen-IgE antibody production and airway eosinophil infiltration in an animal model of airway inflammation.

The aim of the present study was to examine the in vivo effect of interleukin (IL)-12 on a murine model of asthma induced by Dermatophagoides pteronyssinus-derived Der p 1 allergen. C57BL/6 mice immunized with Der p 1 allergen adsorbed to alum/pertussis toxin developed a T-helper type 2 (Th2)-dominant immune response characterized by the presence of IgE antibody, airway eosinophil infiltration and increased production of Th2 cytokine. Intraperitoneal injection of IL-12 (1 or 0.1 microg per day) for 5 days (day -1 to +3) simultaneously with each immunization, inhibited the production of IgE and IgG1 antigen-specific antibodies, whereas production of IgG2a was strongly enhanced. In addition, mice receiving both doses of IL-12 showed a strong inhibition of IL-5 but up-regulation of IFN-gamma production by spleen cells stimulated with antigen. Administration of IL-12 also prevented antigen-induced eosinophil infiltration into the bronchoalveolar area in a dose-dependent manner and the primary inflammatory mediator serotonin in bronchoalveolar lavage (BAL) fluids was also reduced significantly. Taken together, the data indicate that IL-12 has a potent immunomodulatory effect on house-dust-mite-induced allergic disorders and may be used as an efficient agent for immunotherapy.

Allergens↗

PubMed1999

Nasal colonization by Staphylococcus aureus in active, independent, community seniors.

OBJECTIVE: to evaluate the prevalence of nasal colonization with Staphylococcus aureus (SA) in active, independent community seniors and old people in a nursing home. DESIGN: cross-sectional brief questionnaire and screening culture of anterior nares specimens from 165 elders at a community centre and cross-sectional data from a recent survey in a nursing home. RESULTS: the prevalence of SA colonization in community seniors (27%) was similar to that in the nursing home (29%). The proportion of SA isolates that were methicillin-resistant was much lower in the community seniors (2.3%) than in the nursing-home residents (31%). There was less antibiotic resistance in those living at home. CONCLUSION: in community seniors the prevalence of SA colonization was similar to that in nursing-home residents, but the prevalence of methicillin-resistant SA was lower. Susceptibility patterns of antibiotics tested against the SA showed less resistance than isolates from nursing-home patients.

Aged↗

PubMed1998

Dopamine D4 receptor gene polymorphisms and neuroleptic response in schizophrenia.

BACKGROUND: Dopamine D4 receptor (DRD4) gene polymorphisms are associated with various pharmacologic activities. This study investigated whether polymorphisms of 48-bp tandem repeats in the exon 3 of the DRD4 gene are related to neuroleptic response. METHODS: The neuroleptic response at the acute stage of schizophrenia was assessed in 80 (48 men, 32 women) schizophrenic patients. The negative symptoms at remission were also rated. DRD4 genotype was established using the polymerase chain reaction. Patients with genotypes containing an allele with only two repeats (2-2, 2-3, 2-4, 2-6) were assigned to group I (n = 38). Those homozygous for four 48-bp repeats were assigned to group II (n = 42). RESULTS: Thirteen (34.2%) of the 38 group I subjects and 26 (61.9%) of the 42 group II subjects had good neuroleptic response during acute stage treatment (chi 2 6.12, df = 1, p < .02). In remission, the rates of negative symptoms of blunt affect, avolition, and global negative rating were higher in group I than in group II. This was more prominent in men than in women. CONCLUSIONS: The presence of homozygous four 48-bp repeats in both alleles in exon 3 of the DRD4 gene is associated with good neuroleptic response during acute treatment, and with a lower prevalence of negative symptoms at remission, especially in male schizophrenic patients.

Adult↗

PubMed1998

Astrocytes cultured from transgenic mice carrying the added human glial fibrillary acidic protein gene contain Rosenthal fibers.

Mice carrying copies of the human glial fibrillary acidic protein (hGFAP) gene driven by its own promoter have been generated that express the human transgene at different levels (Messing et al.: 152:391-398, 1998). Lines that expressed high levels of the gene died shortly after birth. Astrocyte cultures prepared from a low overexpressor (Tg73.2) exhibited abnormal cytoplasmic inclusions identical to those seen in vivo in the high overexpressors. Astrocytes in the Tg73.2 cultures appear odd-shaped and enlarged, express increased levels of GFAP (both human and mouse), and express alphaB crystallin protein, Hsp27 protein, and vimentin protein. At the light microscopic level, the Tg73.2 astrocytes are filled with eosinophilic deposits surrounded by positive GFAP immunostain. Ultrastructurally, the Tg73.2 astrocytes contain osmophilic deposits on a bed of intermediate filaments identical to Rosenthal fibers found in the brain in Alexander's disease. It seems that Tg73.2 mouse astrocytes in culture do not require additional stress from external sources or contact with other neuroectodermal cells to produce Rosenthal fibers. This suggests that the added hGFAP gene is sufficient to induce Rosenthal fibers and that an excess of GFAP in astrocytes may be detrimental to normal function. We hypothesize that the normal mechanism for GFAP turnover may be insufficient to handle the excess GFAP, thus causing an accumulation of stress proteins. The increased amounts of stress proteins and GFAP results in the formation of Rosenthal fibers, similar to those found in Alexander's disease.

Animals↗

PubMed1998

Differential localization of GABA(A) receptor alpha and beta subunits in the hamster retina and relationship with glutamic acid decarboxylase immunoreactivity.

In order to determine the cellular localization of GABA(A)alpha and beta subunits in the hamster retina, single and double immunocytochemistry was performed in perfuse-fixed hamster retina using commercially-available antibodies against the two receptor subunits and glutamic acid decarboxylase. Strong GABA(A)beta immunoreactivity was found in two strata of the inner plexiform layer and in perikarya of amacrine cells and bipolar cells in the inner nuclear layer. In contrast, no GABA(A)alpha immunoreactivity was detected. All but a few of the GABA(A)beta-immunoreactive amacrine cells were found not to display glutamic acid decarboxylase immunoreactivity. The present results indicate that there is a differential localization of GABA(A)alpha and beta subunits in different neuronal subpopulations in the hamster retina.

Animals↗

PubMed1998

Chemokine inhibition in rat stab wound brain injury using antisense oligodeoxynucleotides.

Traumatic injury to the central nervous system (CNS) results in the breakdown of the blood-brain barrier and recruitment of hematogenous cells at the site of injury. The role of chemokines in this process has been well recognized and they have been regarded as promising targets for development of anti-inflammatory therapies. The expression of monocyte chemoattractant protein (MCP-1), in particular, has been closely linked to macrophage infiltration following trauma in rat brain. In this study we determined whether inhibition of MCP-1 following stab wound injury would reduce macrophage infiltration. Stab wound injured Sprague-Dawley rats were infused with MCP-1 sense or antisense oligonucleotides using an Alzet miniosmotic pump (1 microl/h for 3 days). Three days following injury, widespread gliosis was observed in both groups of rats as judged by glial fibrillary acidic protein (GFAP) immunoreactivity. Immunohistochemistry showed significantly less staining for MCP-1 in antisense treated animals. In addition, the number of macrophages were reduced by 30% in the antisense compared to the sense treated animals (P < 0.05). These results demonstrate that modulation of MCP-1 expression in stab wound injury directly affects monocytic infiltration and provide a basis for MCP-1 inhibition as a therapeutic strategy for controlling inflammatory events of traumatic brain injury.

Animals↗

PubMed1998

Construction of vectors expressing bioactive heterodimeric and single-chain murine interleukin-12 for gene therapy.

It has been well demonstrated that interleukin-12 (IL-12) could be useful to defend against a variety of pathogens, to suppress tumor growth and metastasis, and even to be employed as an adjuvant of vaccines to enhance beneficial type 1 T helper (Th1) cell response over detrimental type 2 T helper (Th2) cell responses. To apply IL-12 genes in gene therapy such as a DNA vaccine, a pIL-12 vector was constructed that contained two cytomegalovirus (CMV) promoters to drive the expression of p35 and p40 subunits, respectively. In addition, a pscIL-12 vector was designed with a linker to fuse p35 cDNA with p40 cDNA to produce a single-chain IL-12 protein, ensuring not only that the expression of p35 and p40 subunits was equally expressed, but also that no free p40 subunits interfered with IL-12 activity. The data suggested pIL-12 could produce a rather high level of biologically active IL-12 after transfection of COS cell lines as well as C2C12 muscle cell lines, as measured by both concanavalin A blast proliferation assay and enzyme-linked immunosorbent assay. Interestingly, the pscIL-12 vector could also express a bioactive murine IL-12 fusion protein in vitro. Furthermore, in vivo functional studies also demonstrated that mice co-immunized with a pS vector expressing the major envelope protein of hepatitis B virus (HBV) and IL-12 vectors encoding native IL-12 or single-chain IL-12 fusion protein elicited higher levels of IgG2a anti-HBs antibody and of Th1-related cytokine. Because p35 and p40 genes can be expressed in a vector by using a single promoter, pscIL-12 should be useful in future applications for nucleic acid vaccination or for gene therapy against diseases.

Animals↗

PubMed1998

Development of Th1 and Th2 populations and the nature of immune responses to hepatitis B virus DNA vaccines can be modulated by codelivery of various cytokine genes.

In this study, we provide direct evidence that the magnitude and nature of the immune response to a DNA vaccine can be differentially regulated by codelivery of various mouse cytokine genes. Mice immunized with a hepatitis B virus (HBV) DNA vaccine and the IL-12 or IFN-gamma gene exhibited a significant enhancement of Th1 cells and increased production of anti-HBV surface IgG2a Ab, as well as a marked inhibition of Th2 cells and decreased production of IgG1 Ab. In contrast, coinjection of the IL-4 gene significantly enhanced the development of specific Th2 cells and increased production of IgG1 Ab, whereas Th1 differentiation and IgG2a production were suppressed. Coinjection of the IL-2 or the granulocyte-macrophage-CSF gene enhanced the development of Th1 cells, while the development of Th2 cells was not affected, and the production of IgG1 and IgG2a Ab were both increased. The CTL activity induced by HBV DNA vaccination was most significantly enhanced by codelivery of the IL-12 or IFN-gamma gene, followed by the IL-2 or granulocyte-macrophage-CSF gene, whereas codelivery of the IL-4 gene suppressed the activity. When challenged with HBV surface Ag (HBsAg)-expressing syngeneic tumors, significant reduction of tumor growth was observed in mice that were coadministered the IL-12 gene but not the IL-4 gene. Taken together, these results demonstrate that application of a cytokine gene in a DNA vaccine formulation can influence the differentiation of Th cells as well as the nature of an immune response and may thus provide a strategy to improve its prophylactic and therapeutic efficacy.

Adjuvants, Immunologic↗

PubMed1998

Prospective, randomized trial comparing pain and complications between diathermy and scissors for closed hemorrhoidectomy.

PURPOSE: The aim of this study was to assess pain and complication rates after closed hemorrhoidectomy with the use of either scissors or diathermy excision. METHODS: Ninety-one consecutive patients were prospectively randomly assigned by use of sealed envelopes to Group A (diathermy dissection; n = 44) or Group B (scissors dissection; n = 47). The resulting hemorrhoidal pedicle after hemorrhoidal dissection was transfixed and buried under the mucosa, which was closed with 3-0 chromic catgut. RESULTS: The median time taken for surgery was ten minutes in both groups. The range for Group A was 5 to 25 minutes, and the range for Group B was 5 to 20 minutes. There were no statistically significant differences in the pain scores between the two groups for any of the seven postoperative days studied. The median number of pethidine injections in Group A was 1 and in Group B was 0 (P < 0.009). The number of oral analgesic tablets used was 8 (range, 4-10) and 14 (range, 0-10) for Groups A and B, respectively (P < 0.001). The number of tubes of topical lignocaine jelly used was 14 (range, 0-22) and 14 (range, 7-88) in Groups A and B, respectively. Two patients in each group developed secondary hemorrhage, but no patient had anal stricturing. CONCLUSION: No excessive complications are seen with closed hemorrhoidectomy, and diathermy seems to require less postoperative analgesic medicine than scissors for closed hemorrhoidectomy except in the first 24 hours.

Adult↗

PubMed1998

Immune status in preschool children born after mass hepatitis B vaccination program in Taiwan.

A mass hepatitis B vaccination program began in Taiwan in 1984. In order to determine the immune status of hepatitis B virus (HBV) infection among preschool children, a total of 25 kindergartens in 20 townships and metropolitan precincts in central Taiwan were randomly selected through stratified sampling. Serum specimens of 2130 healthy preschool children aged 2-6 years old were screened for the HBV markers and liver function in 1996. HBV surface antigen (HBsAg), antibody against HBsAg (anti-HBs) and antibody against HBV core antigen (anti-HBc) were tested by reverse passive hemagglutination (RPHA), enzyme immunoassay (EIA) and radioimmunoassay (RIA) using commercial kits. HBV vaccination rate of the preschool children was 98%, and complete vaccination rate (three or four doses of HBV vaccine) was 94%. The HBsAg seropositive rate was 4.5% among incomplete vaccinees and 1.3% among complete vaccinees. The anti-HBs was detectable in 1637 of 2000 complete vaccinees (81.9%) and in 53 of 88 incomplete vaccinees (60.2%). The overall prevalence rate of anti-HBc was 2.4% (52 of 2130). The older the age, the lower the anti-HBs seropositive rate. The anti-HBs seropositive rats for complete vaccinees were 100% at 2 years old and 75% at 6 years old. There were no significant differences in HBsAg-seropositive rates and anti-HBs-seropositive rates among different residential areas or ethnic groups. There were three children who were seropositive on HBsAg, anti-HBs and anti-HBc, whether they were infected by the vaccine-induced escape mutant of HBV deserves scrutiny.

Age Factors↗

PubMed1998

Multinuclear NMR resonance assignments and the secondary structure of Escherichia coli thioesterase/protease I: a member of a new subclass of lipolytic enzymes.

Escherichia coli thioesterase/protease I is a 183 amino acid protein with a molecular mass of 20,500. This protein belongs to a new subclass of lipolytic enzymes of the serine protease superfamily, but with a new GDSLS consensus motif, of which no structure has yet been determined. The protein forms a tetramer at pH values above 6.5 and exists as a monomer at lower pH values. Both monomer and tetramer are catalytically active. From analysis of a set of heteronuclear multidimensional NMR spectra with uniform and specific amino acid labeled protein samples, we have obtained near-complete resonance assignments of the backbone 1H, 13C and 15N nuclei (BMRB databank accession number 4060). The secondary structure of E. coli thioesterase/protease I was further deduced from the consensus chemical shift indices, backbone short- and medium-range NOEs, and amide proton exchange rates. The protein was found to consist of four beta-strands and seven alpha-helices, arranged in alternate order. The four beta-strands were shown to form a parallel beta-sheet. The topological arrangement of the beta-strands of -1x, +2x, +1x appears to resemble that of the core region of the alpha beta hydrolase superfamily, typically found in common lipases and esterases. However, substantial differences, such as the number of beta-strands and the location of the catalytic triad residues, make it difficult to give a definitive classification of the structure of E. coli thioesterase/protease I at present.

Amino Acid Sequence↗

PubMed1998

Inflammation in traumatic brain injury: role of cytokines and chemokines.

A traumatic injury to the adult mammalian central nervous system (CNS), such as a stab wound lesion, results in reactive astrogliosis and the migration of hematogenous cells into the damaged neural tissue. The roles of cytokines and growth factors released locally by the damaged endogenous cells are recognized in controlling the cellular changes that occur following CNS injury. However, the role of chemokines, a novel class of chemoattractant cytokines, is only recently being studied in regulating inflammatory cell invasion in the injured/diseased CNS (1). The mRNAs for several chemokines have been shown to be upregulated in experimental allergic encephalomyelitis (EAE), an inflammatory demyelinating disease of the CNS, but chemokine expression in traumatic brain injury has not been studied in detail. Astrocytes have been demonstrated to participate in numerous processes that occur following injury to the CNS. In particular, astrocytic expression of cytokines and growth factors in the injured CNS has been well reviewed (2). Recently a few studies have detected the presence of chemokines in astrocytes following traumatic brain injury (3,4). These studies have suggested that chemokines may represent a promising target for future therapy of inflammatory conditions. This review summarizes the events that occur in traumatic brain injury and discusses the roles of resident and non-resident cells in the expression of growth factors, cytokines and chemokines in the injured CNS.

Animals↗