Biomedical subjects

Y W Lin

Publications and source records attributed to Y W Lin.

At least 73 records · Page 4Linked to original sources

PubMed1995

Spontaneous resolution of symptoms in an infant with a congenital dural caroticocavernous fistula.

We report a 5-week-old boy with a congenital dural caroticocavernous fistula (CCF). He had gradually progressive proptosis, dilated conjunctival veins, chemosis, abducens nerve palsy and an objective bruit. Angiography of the right common carotid artery revealed fistulous communication in the cavernous sinus (CS) region. The CS was fed by the middle meningeal artery and drained through the superior ophthalmic vein and the superior petrosal vein. The child's symptoms and signs disappeared within a few weeks and did not recur over 11 months. At that time, however, angiography still showed a small communication between the right external carotid artery and the CS.

Arteriovenous Fistula↗

PubMed1995

Augmentation by aphidicolin of 1-beta-D-arabinofuranosylcytosine-induced c-jun and NF-kappa B activation in a human myeloid leukemia cell line: correlation with apoptosis.

1-beta-D-arabinofuranosylcytosine (ara-C) (2 microM) can induce apoptosis in a human myeloid leukemia cell line, U937, after 4 h of incubation. Pretreatment of cells with aphidicolin (2 microM) augments ara-C-induced apoptosis, since it was first observed at 0.4 microM ara-C and became more intense at 2 and 10 microM. Although aphidicolin itself had a marginal effect on c-jun expression, it significantly augmented ara-C induced c-jun upregulation by shortening the lag time and lowering ara-C concentrations necessary for the induction of detectable c-jun transcripts. Aphidicolin and ara-C acted synergistically to increase NF-kappa B DNA binding activity as determined by an electrophoretic mobility shift assay. Expression of c-myc was slightly increased through the DNA degradative phase, and was then downregulated. Thus, the activation of NF-kappa B and c-jun expression seems to be well correlated with the potentiation by aphidicolin of ara-C-induced apoptosis.

Antimetabolites, Antineoplastic↗

PubMed1995

Somatic cell mutation frequency at the HPRT, T-cell antigen receptor and glycophorin A loci in Cockayne syndrome.

Skin fibroblasts of patients with Cockayne syndrome (CS) are hypersensitive to the lethal or mutagenic effect of ultraviolet light, which may cause genetic instability. Up to now, however, no systematic study of in vivo somatic cell mutation in CS cells has been reported. This article describes our investigation of the mutation frequencies (Mfs) at three different loci, i.e. hypoxanthine-guanine phosphoribosyl transferase (HPRT), T-cell antigen receptor (TCR) and glycophorin A (GPA), in six patients with CS. Mfs at the HPRT and TCR loci were found to be within the normal range as determined in age-matched controls. In the GPA locus of two patients, there was a slight increase, but it was much smaller than that reported in other DNA repair deficient syndromes. The frequency of spontaneous HPRT mutation in Epstein-Barr virus transformed B-lymphoblastoid cells derived from CS patients was similar to that in cells from normal children. The molecular characterization of the representative HPRT mutant T cell clones from CS patients did not show any structural alterations. These results may explain, at least in part, why CS is not associated with predisposition to cancer.

Adolescent↗

PubMed1995

Ultrasound-guided percutaneous transhepatic gallbladder drainage followed by laparoscopic cholecystectomy: a new trial in the treatment of severe acute suppurative cholecystitis.

Seven cases of acute suppurative cholecystitis underwent percutaneous transhepatic gallbladder drainage followed by laparoscopic cholecystectomy at the Tainan Municipal Hospital. All the patients had frank septic phenomena clinically, including fever, jaundice, leukocytosis and unstable blood pressure. Organisms were cultured from both blood and bile specimens. Ultrasound-guided transhepatic puncture of the gallbladder was performed for bile drainage, and laparoscopic cholecystectomy was subsequently performed two to five days later after the patients had stabilized. No procedure-related complications from either percutaneous transhepatic gallbladder drainage or laparoscopic cholecystectomy were observed. All patients had early recovery, shortened hospital stay and good cosmetic results. These preliminary results show that laparoscopic cholecystectomy is a safe method and can be employed in those patients with symptomatic gallstone associated with suppurative cholecystitis after preoperative biliary drainage.

Acute Disease↗

PubMed1994

Pyrrolidine dithiocarbamate, a potent inhibitor of nuclear factor kappa B (NF-kappa B) activation, prevents apoptosis in human promyelocytic leukemia HL-60 cells and thymocytes.

We examined the effect of pyrrolidine dithiocarbamate (PDTC), which potently blocks the activation of nuclear factor kappa B (NF-kappa B), on the induction of apoptosis by a variety of agents. Treatment of a human promyelocytic leukemia cell line, HL-60, with 10 micrograms/mL etoposide or 2 microM 1-beta-D-arabinofuranosylcytosine induced NF-kappa B activation within 1 hr and subsequently caused apoptosis within 3-4 hr. The simultaneous addition of 50-500 microM PDTC with these agents blocked NF-kappa B activation and completely abrogated both morphologically apoptotic changes and internucleosomal DNA fragmentation for up to 6 hr. However, PDTC failed to inhibit the endonuclease activity contained in the whole cell lysates. The inhibitory effect of PDTC was also observed in etoposide- and dexamethasone-induced apoptosis in human thymocytes at a concentration of 1-10 microM. Since PDTC has both antioxidant and metal-ion chelating activities, we tested the effects of N-acetyl-L-cysteine (NAC) (antioxidant) or o-phenanthroline (OP) (metal-ion chelator) on the induction of apoptosis. Pretreatment of HL-60 cells or thymocytes with 100-500 microM OP for 2 hr, but not 10-60 mM NAC, suppressed subsequent occurrence of apoptosis induced by etoposide. These results suggest that the activation of NF-kappa B plays an important role in the apoptotic process of human hematopoietic cells.

Acetylcysteine↗

PubMed1994

Stimulation of proliferation by 3,3',5-triiodo-L-thyronine in poorly differentiated human hepatocarcinoma cells overexpressing beta 1 thyroid hormone receptor.

To understand the role of thyroid hormone nuclear receptors (TRs) in hepatocarcinogenesis, we characterized the TRs in nine human hepatocarcinoma cell lines. The expression of TR proteins is receptor subtype- and cell type-dependent. TR alpha 1 protein expresses similarly at a low level in each of the nine cell lines. In contrast, TR beta 1 is overexpressed in hepatocarcinoma cells which are poorly differentiated. Furthermore, thyroid hormone was found to stimulate the proliferation of cells in which TR beta 1 is overexpressed. These results suggest that TR beta 1 is most likely involved in the differentiation and proliferation of hepatocarcinoma cells. Our studies have shed new light in the understanding of the role of TRs in liver carcinogenesis.

Biomarkers↗

PubMed1994

Identification of multiple genes in bovine retinal pericytes altered by exposure to elevated levels of glucose by using mRNA differential display.

Loss of capillary pericytes, a characteristic finding in diabetic retinopathy, is strongly associated with hyperglycemia. The pathologic aberrations associated with diabetic retinopathy are localized primarily in the retinal capillaries and are only poorly reversed by subsequent euglycemic control. Since hyperglycemia significantly inhibits pericyte growth in culture, we investigated the regulation of gene expression in retinal pericytes exposed to physiologic (5.5mM) and pathologic (20 mM) glucose concentrations. By utilizing modifications of the mRNA differential display technique, over 14,000 mRNA species were screened, and 35 candidate clones were obtained. Partial DNA sequence demonstrated that 25 of these were distinct genes, including 7 known, 16 previously unreported, and 2 sequences with known homologues. Northern blot analysis demonstrated altered gene expression in 10 (40%), undetectable signals in 12 (48%), and nonregulation in 3 (12%). Genes with glucose-regulated expression included those encoding fibronectin (51% +/- 15%, P = 0.003; mean percentage of control +/- SD), caldesmon (68% +/- 18%; P = 0.026), two ribosomal proteins (201% +/- 72%, P = 0.011; 136% +/- 16%, P = 0.036), Rieske FeS reductase (66% +/- 17%; P = 0.029), three previously unreported sequences (57%, 167%, 271%), and molecules homologous to autoantigens (213%) and tyrosine kinases (down 16- to 33-fold). Caldesmon protein concentrations in pericytes and smooth muscle cells demonstrated decreases by Western blot analysis concordant with mRNA levels. These studies identify genes whose expression is significantly altered after 7 days of exposure to elevated glucose levels and provide new targets for understanding the adverse effects of hyperglycemia on vascular cells. In addition, this study provides strong support for the use of differential mRNA display as a method to rapidly isolate differentially expressed genes in metabolic systems.

Amino Acid Sequence↗

PubMed1994

Variable susceptibility to apoptosis induced by calcium ionophore in hybridomas between HL-60 promyelocytic and CEM T-lymphoblastic leukemia cell lines: relationship to constitutive Mg(2+)-dependent endonuclease.

We recently reported that treatment with calcium ionophore, A23187, induces apoptosis in human myelogenous leukemia cells but causes necrotic cell death in T-lymphoblastic leukemia cells. To better understand the underlying mechanisms of such different modes of cell death, we established hybridomas between HL-60 promyelocytic and CEM T-lymphoblastic leukemia cells. The resulting hybridomas were divided into three groups in terms of their susceptibility to apoptosis following exposure to A23187: (1) hybridomas highly sensitive to apoptosis, (2) hybridomas with intermediate sensitivity to apoptosis which occurs later and to a lesser extent, and (3) hybridomas resistant to apoptosis. However, growth inhibition after 72 h of incubation and an initial rise in intracellular free calcium concentrations induced by A23187 were similar in the three groups. Expression of Ca(2+)-independent/Mg(2+)-dependent endonuclease, which had an optimal pH of 7.5-8.5 and was inhibited by Zn2+, was correlated with the susceptibility of the hybridomas to A23187-induced apoptosis. Thus, this endonuclease may play, at least in part, an important role in the induction of apoptosis in leukemia cell lines. Analysis of hybridomas between apoptosis-sensitive and apoptosis-resistant cells is useful in the elucidation of genetic factors which regulate cell death.

Apoptosis↗

PubMed1994

Somatic mutations at T-cell antigen receptor and glycophorin A loci in pediatric leukemia patients following chemotherapy: comparison with HPRT locus mutation.

Frequencies of somatic mutations in pediatric patients with leukemia were evaluated following intensive treatment at three different loci: the hypoxanthine-guanine phosphoribosyl transferase (HPRT), T-cell antigen receptor (TCR), and glycophorin A (GPA) gene. Thirty-two children with acute lymphoblastic leukemia (ALL), nine children with acute myelogenous leukemia (AML), and 20 age-matched healthy controls were included in the study of mutant frequencies (Mfs) at the HPRT and TCR loci. Among these patients and controls, individuals with heterozygous MN blood type, i.e., 14 children with ALL, three children with AML, and nine healthy controls, served for the further assessment of variant frequency (Vf) at the GPA locus. In ALL patients, geometric mean Mfs and Vfs at these loci were significantly higher than in healthy controls. The high Mf value at the HPRT locus persisted for up to 8 years after the end of chemotherapy. On the other hand, the Mf values at the TCR locus and Vf values at the GPA locus declined gradually with time. In AML patients, on the other hand, the geometric mean Mf only at the TCR locus was significantly higher than in the controls, albeit to a lesser degree than in ALL patients. These data suggest that anti-cancer therapy induces somatic mutations at various loci and that ALL patients are more susceptible to mutagenic intervention than are AML patients.

Adolescent↗

PubMed1994

In vivo administration of granulocyte colony-stimulating factor promotes neutrophil survival in vitro.

We recently showed that recombinant human granulocyte-colony stimulating factor (rhG-CSF) maintained the viability of human neutrophils in incubation for up to 72 hours. However, it is not known whether rhG-CSF can enhance neutrophil survival in in vivo situations. To clarify this issue, we investigated neutrophil survival in vitro following in vivo injection of rhG-CSF. Neutrophils were obtained from 4 pediatric patients with malignancies and healthy adult volunteers before and after rhG-CSF administration. Neutrophils obtained before rhG-CSF treatment started to undergo apoptosis after 24 h of incubation. In contrast, the survival of neutrophils drawn after rhG-CSF administration increased by approximately 24 h. Concomitantly, the appearance of typical ladder-like DNA fragmentation was delayed. Such an increase in neutrophil survival was inhibited by co-incubation with either H 7 (10 mumol/l) or H 8 (20 mumol/l), which worked as protein kinase C inhibitors. Although our study did not measure neutrophil survival in vivo directly, it provides us with further evidence that rhG-CSF may function to prolong neutrophil life expectancy in vivo.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1994

Bilateral thoracoscopic lower sympathetic-splanchnicectomy for upper abdominal cancer pain.

Upper abdominal pain secondary to cancer may cause great disability to patients. Surgical sympathetic-splanchnicectomy, or coeliac plexus block, has been used to relieve intractable upper abdominal cancer pain from stomach, liver, gallbladder or pancreas for a long time. There are, however, intrinsic disadvantages when performing these procedures. Due to our long experience of therapeutic thoracoscopy, we recently performed bilateral thoracoscopic sympathetic-splanchnicectomy on 14 patients (eight male and six female) for relief of pain from primary or metastatic upper abdominal cancers. Most of them were satisfied with the immediate pain relief after the operation. In this new era of therapeutic endoscopy, endoscopic surgery will gradually take the place of open methods in treatment of many diseases. It can be anticipated that thoracoscopic lower sympathetic-splanchnicectomy is undoubtedly a good alternative method for management of intractable upper abdominal pain.

Abdominal Pain↗

PubMed1993

Steroidogenesis in Fundulus heteroclitus V.: purification, characterization, and metabolism of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one by intact follicles and its role in oocyte maturation.

In vitro steroidogenesis of ovarian follicles incubated with radioactive precursors or a Fundulus heteroclitus pituitary extract (FPE) was investigated. Steroids were extracted from both the medium and follicular tissue and fractionated by liquid or thin-layer chromatography. A similar pattern of steroid metabolites was obtained with either [14C]pregnenolone or [14C]progesterone as exogenous precursor. Several metabolites comigrated with known reference steroids and thus were tentatively identified. Some have been previously reported to induce germinal vesicle breakdown (GVBD) in this and other species, particularly 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (DHP). [3H]DHP added to intact follicles or denuded oocytes was also extensively metabolized. All the DHP metabolites produced by the intact follicle were tested for biological activity. Three of the metabolites were almost as effective inducers of GVBD as DHP itself, and two were tentatively identified as 5 alpha-pregnan-3 alpha,17 alpha,20 beta-triol and 5 alpha-pregnan-3 beta,17 alpha,20 beta-triol. However, DHP was the most potent and the quickest inducer of GVBD, indicating that its maturational action is not due to metabolic conversion to a more active form. In addition, we found two very active fractions after HPLC analysis of steroid extracts from FPE-stimulated follicles: one that corresponded to and was further identified (mass spectroscopy) as DHP and a second tentatively identified as the DHP metabolite 5 alpha-pregnan-3 beta,17 alpha,20 beta-triol. This study provides strong evidence that DHP plays the major role as a maturation inducing-steroid in F. heteroclitus, even though DHP is not the only active steroid produced by maturing follicles.

Animals↗

PubMed1993

[Chemical constituents of Sagittaria sagittifolia L].

One terpenoids has been isolated from the MeOH extract of Sagittaria sagittifolia by repeated chromatography on silica gel. Its structure was identified as sandaracopimaric acid on the basis of spectral and physical data. Sandaracopimaric acid has good immunosuppression action.

Diterpenes↗

PubMed1993

[Staffing levels and patient needs in the intensive care unit].

The current study sought to utilize a patient classification system to investigate staffing and patient needs along with nursing care distribution in our intensive care units. The study employed a factor type analysis to design a patient need checklist (for our six ICUs) in order to determine staff load and nursing requirements. Snapshot observations were also taken to survey the distribution of nursing care time. The results of the two methods provide an estimate of current staffing needs, they also show that there is no significant difference between our surgical and internal medicine wards. On average, direct care accounts for 40.1% of the time schedule; indirect care, 37.3%; related care, 6.0%; and individual time, 16.6%. The average patient grade lies between I and III; and workload index, between 4.4 and 11.5. The average nursing time per patient per shift is 2.88 hours, and the average workload per person is estimated at 5.7-5.8 hours. By comparing the number of personnel currently employed and the estimated number needed, we discovered that two units are understaffed, and three are overstaffed. The understaffed units are all surgical units; the overstaffed ones, internal medicine units. To conclude the study, we examined the nature and complexity of nursing duties in the hopes of returning non-nursing responsibilities to the proper medical organizations. Our ultimate goal is to realize the full potential and improve the quality of our nursing personnel.

Female↗

PubMed1993

Diagnostic and therapeutic interventions in post-laparoscopic cholecystectomy biliary complications.

Radiological imaging and therapeutic interventions were performed in eight patients with biliary complications following laparoscopic cholecystectomy. The diagnostic approach and the outcome of the therapeutic procedures were evaluated. Complications observed were bile leakage from the cystic duct stump (n = 2); erroneous identification of the cystic duct leading to common hepatic duct transection (n = 1) and hepatic duct ligation (n = 2); liver abscess (n = 1); and retained common duct stones (n = 2). Diagnostic ultrasonography is capable of detecting the presence of abnormal fluid collection and the diameter of the common duct with or without the presence of a stone, although bile leaks and retained common duct stones can only be demonstrated by either endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography. Once a bile leak had been confirmed, therapeutic endoscopic biliary stenting was successfully applied in one patient while the other received percutaneous transhepatic biliary drainage. Definitive diagnosis of retained common duct stone was established by endoscopic retrograde cholangiopancreatography, and immediate endoscopic sphincterotomy with stone extraction was performed. Follow-up radiological imaging was done to determine the effectiveness of the therapeutic procedures applied in each patient. All our patients improved clinically, and further surgical intervention was not needed.

Biliary Tract Diseases↗

PubMed1992

Steroidogenesis in Fundulus heteroclitus. IV. Dichotomous effects of a phorbol ester on ovarian steroid production and oocyte maturation.

The possible role of protein kinase C (PKC) activation in mediating the stimulatory actions of a Fundulus pituitary extract (FPE) on ovarian steroidogenesis and oocyte maturation was investigated. The phorbol ester, phorbol 12-myristate 13-acetate (PMA), alone slightly increased basal 17 alpha-hydroxy,20 beta-dihydroprogesterone (DHP) and 17 beta-estradiol (E2) synthesis and significantly stimulated germinal vesicle breakdown (GVBD). Addition of FPE promoted synthesis of DHP, testosterone (T), and E2, and initiated GVBD. Phorbol ester inhibited FPE-induced steroidogenesis but increased the number of oocytes that underwent GVBD. Phorbol ester also markedly impeded induction of steroidogenesis by dibutyryl cAMP and differentially affected the conversion of 25-hydroxycholesterol, pregnenolone, or progesterone to DHP, T, and E2: DHP production was not affected; T production diminished; and E2 synthesis increased (T aromatization also increased). These results suggest an inhibitory role for the PKC pathway on FPE-induced ovarian steroid production, with PMA appearing to affect various steroidogenic steps. The stimulatory action of PMA on oocyte maturation seems to be independent of follicular steroid production since aminoglutethimide, an inhibitor of steroidogenesis, did not block PMA-induced GVBD. Moreover, PMA had a marked stimulatory effect on GVBD in denuded oocytes. Thus, in contrast to the inhibitory role found for the PKC pathway on ovarian follicular steroidogenesis, activation of PKC in the oocyte may serve as a signal-transducing mechanism leading to GVBD.

Alkaloids↗

PubMed1992

Fundulus heteroclitus gonadotropins. 3. Cloning and sequencing of gonadotropic hormone (GTH) I and II beta-subunits using the polymerase chain reaction.

mRNA was isolated from Fundulus heteroclitus pituitaries and used to construct a cDNA library in lambda gt22A. A series of synthetic oligonucleotides, based on conserved regions of teleost gonadotropic hormone (GTH) beta-subunits, were constructed and used as primers in the polymerase chain reaction (PCR) to amplify GTH cDNAs. Appropriate length PCR products were subcloned and sequenced. Eight clones were eventually identified as cDNAs encoding two distinct beta-subunits of F. heteroclitus, GTH I and GTH II. By comparison with known GTH sequences, putative signal sequences of 19 end 21 amino acids and mature beta-subunits of 95 and 115 amino acids were found for GTH I and GTH II, respectively. Both beta-subunits had well conserved cysteine positions when aligned with other members of the glycoprotein family. The elucidation of the complete nucleotide sequences of two types of F. heteroclitus GTH provides definitive proof that in this species there are at least two distinct forms of pituitary GTH analogous to the classical luteinizing hormone-follicle stimulating hormone family.

Amino Acid Sequence↗

PubMed1992

Familial occurrence of growth hormone deficiency and primary hypothyroidism.

We examined endocrine function in three male siblings with growth hormone (GH) deficiency and primary hypothyroidism. Low GH responses to various provocative tests were revealed in all three. Exaggerated thyrotropin (TSH) responses to thyrotropin-releasing hormone increased basal TSH levels, and low free thyroxine levels were also found in all three. Additionally, a low testosterone response to human chorionic gonadotropin and low gonadotropin responses to luteinizing hormone-releasing hormone were noted in the youngest sibling. Skull X-ray films, computerized tomography and magnetic resonance imaging revealed no abnormalities of the pituitary gland or sella turcica. The GH gene was intact in all of the children and their parents. We diagnosed all siblings as having GH deficiency and primary hypothyroidism. This is the first report of familial occurrence of GH deficiency and primary hypothyroidism.

Adolescent↗