Biomedical subjects

C M Shih

Publications and source records attributed to C M Shih.

At least 19 recordsLinked to original sources

PubMed2004

Midazolam attenuates adenosine diphosphate-induced P-selectin expression and platelet-leucocyte aggregation.

BACKGROUND AND OBJECTIVE: The expression of P-selectin on the surface of platelets and platelet-leucocyte conjugate formation are considered to be an indicator of platelet activation in thrombotic and inflammatory disease. Midazolam is a widely used sedative and anaesthetic induction agent. It may inhibit platelet aggregation and suppress interleukin-6 and -8 response in human leucocytes, but any effect on the adhesion of activated platelets to leucocytes remains obscure. We have examined the influence of midazolam on adenosine diphosphate (ADP)-induced platelet surface P-selectin expression and platelet-leucocyte aggregation in whole blood. METHODS: Human whole blood was stimulated with 2 x 10(-5)M ADP in the presence of midazolam (3 x 10(-4) to 3 x 10(-6)M). Samples were stained with a fluorochrome-conjugated CD62P and CD41a antibody for detecting human platelet P-selectin antigens. The leucocyte subpopulations were separately gated and platelet-leucocyte aggregates were defined as cells found positive for CD45 and CD62P. All samples were analysed and were electronically separated into specific cell types (platelets, neutrophils, monocytes and lymphocytes) according to their typical forward/side scattering by flow cytometry. RESULTS: Midazolam significantly inhibited ADP-induced platelet P-selectin expression and attenuated platelet-leucocyte aggregation (mainly in neutrophils and monocytes) in a dose-dependent manner with a maximum inhibitory effect at 3 x 10(-4)M (P < 0.01). CONCLUSIONS: This study demonstrated that midazolam decreases the ADP-induced expression of platelet surface P-selectin and platelet-leucocyte aggregation.

Adenosine Diphosphate↗

PubMed2001

Growth inhibition of cultured smooth muscle cells by corrosion products of 316 L stainless steel wire.

The potential cytotoxicity on vascular smooth muscle cells of corrosion products from 316 L stainless steel, one of most popular biomaterials of intravascular stents, has not been highlighted. In this investigation, 316 L stainless steel wires were corroded in Dulbecco's modified eagle's medium with applied constant electrochemical breakdown voltage, and the supernatant and precipitates of corrosion products were prepared as culture media. The effects of different concentrations of corrosion products on the growth of rat aortic smooth muscle cells were conducted with the [3H]-thymidine uptake test and cell cycle sorter. Both the supernatant and precipitates of corrosion products were toxic to the primary culture of smooth muscle cells. The growth inhibition was correlated well with the increased nickel ions in the corrosion products when nickel concentration was above 11.7 ppm. The corrosion products also changed cell morphology and induced cell necrosis. The cell growth inhibition occurred at the G0/G1 to S transition phase. Similar to our recent study of nitinol stent wire, the present investigation also demonstrated the cytotoxicity of corrosion products of 316 L stainless steel stent wire on smooth muscle cells, which might affect the poststenting vascular response.

Animals↗

PubMed2001

Endovascular aortic graft exclusion of abdominal aortic aneurysm.

Endovascular repair of abdominal aortic aneurysms has evolved dramatically within the past few years. This study reports the first successful case in Taiwan area of infrarenal abdominal aortic aneurysm treated with endovascular aortic bifurcational stent-graft. Minimally invasive surgery leading to early recovery, mobilization and shortened hospital day was promising. In addition, there were no local, remote or systemic complications during a 18-month follow-up. Thus, the procedure is an attractive alternative in its potential to reduce morbidity and mortality associated with open surgical repair, especially for patients who are not surgical candidates because of comorbidities. Careful patient selection and more experiences with refined endograft models will elucidate the feasible alternative to conventional surgical repair.

Aged↗

PubMed2000

Hantavirus infection in Taiwan: the experience of a geographically unique area.

Hantaviruses are rodent-borne viruses, and they, mainly the Hantaan (HTN) serotype, are the causative agents of a group of febrile nephropathies known as "hemorrhagic fever with renal syndrome (HFRS). " Despite the fact that HFRS is frequently reported in China, with an annual incidence of 50,000-100,000 cases, one puzzling observation that no local case of HFRS has been confirmed in Taiwan has yet to be explained. We hypothesized that the hantavirus strain prevailing in Taiwan mainly belongs to the mild strain, the Seoul (SEO) strain, and the absence of severe disease was related to the absence of HTN. To test these hypotheses, this epidemiologic study was performed, including a seroprevalence survey and phylogenetic analysis on hantavirus isolated from the rodent population trapped in major seaports, rural, and mountainous areas of Taiwan. This study also included rodents and viruses from two isolated islands, Kinmen and Matzu, which are geographically adjacent to the east coast of mainland China. There were a total of 5,461 rodents of 16 species captured, and R. norvegicus was the most common species, with an antibody prevalence much higher in international seaports (20%) than in rural regions (approximately 5%) and intermediate in some domestic seaports. By reverse transcriptase polymerase chain reaction (RT-PCR), 33.9% of the seropositive R. norvegicus were found to have amplifiable hantavirus sequences in their lung tissues, and subsequent phylogenetic analyses indicated that almost all hantavirus in Taiwan was most closely related to the prototype SEO strain, and no HTN strain was recovered from any rodent species indigenous to Taiwan. The seroprevalence of SEO infection in R. norvegicus on Kinmen and Matzu was also different from that in southern provinces of China but closely resembled that in seaports in Taiwan, and the SEO identified was genetically linked to Taiwanese SEO strains. These results substantiate our hypotheses, and suggest that the epidemiology of hantavirus infection in Taiwan are different from that in China, where the HTN and SEO strains and HFRS concurrently prevail.

Animals↗

PubMed2000

Lack of evidence of association of p21WAF1/CIP1 polymorphism with lung cancer susceptibility and prognosis in Taiwan.

An association between the Arg allele of the p21WAF1/CIP1 codon 31 polymorphism and lung cancer has been reported. However, the genotype distribution of the p21 codon 31 polymorphism, as well as the association of this polymorphism with lung cancer risk and prognosis, remain undefined in the Taiwanese population. Therefore, we investigated the genotype distribution of the p21 codon 31 polymorphism in 155 lung cancer patients and 189 non-cancer controls. The genotype frequencies in the Taiwanese non-cancer controls were 0.51 (Ser) and 0.49 (Arg). Chi2 analysis indicated significant differences in Taiwanese genotype distribution of p21 from those reported for Swedes (P=0.001), Caucasians (P=0.001), Indians (P=0.001), and African-Americans (P=0.001). However, our data did not demonstrate an association of the Arg allele of the p21 polymorphism with lung cancer risk in Taiwan. Lung cancer patients with Ser/Arg and Arg/Arg genotypes were at a nonsignificant 1.15-fold increased risk of lung cancer when compared to individuals with the Ser/Ser genotype (95%CI, 0.70-1.86). In addition, although p21 is a downstream target of p53, we found no significant correlation of the p21 polymorphism with the p53 polymorphism and p53 gene mutation in lung cancer patients. We further investigated the association of the p21 polymorphism with prognosis in 154 lung cancer patients. Patients with the Ser/Ser genotype tended to have a poorer prognosis than those with the Ser/Arg and Arg/Arg genotypes (P=0.097, by the log rank test). Our data suggest that the p21 codon 31 polymorphism may not play a significant role in cancer susceptibility and the prognosis of lung cancer patients in Taiwan.

Adenocarcinoma↗

PubMed2000

Virus infection in patients with histiocytic necrotizing lymphadenitis in Taiwan. Detection of Epstein-Barr virus, type I human T-cell lymphotropic virus, and parvovirus B19.

The relationship of Epstein-Barr virus (EBV), type I human T-cell lymphotropic virus (HTLV-I), and parvovirus B19 to histiocytic necrotizing lymphadenitis was studied prospectively in 10 Taiwanese patients using materials obtained by fine-needle aspiration and lymph node biopsy. The presence of EBV was detected by in situ hybridization for EBV-encoded RNA expression. Immunocytochemistry was used to detect virus-encoded protein for EBV and parvovirus B19. DNA in situ hybridization and polymerase chain reaction were performed to determine the existence of HTLV-I provirus. Expressions of EBV-encoded RNA and Fas ligand were detected in all cases. Expression of EBV-encoded protein was identified in only 1 case. Neither HTLV-I nor parvovirus B19 was detected in any case.

Adolescent↗

PubMed1999

Clinical and morphologic features of hypertrophic cardiomyopathy in elderly patients 85 years or older.

We studied the distinctive morphology of the left ventricle (LV) and attempted to relate advanced age and hypertension to this characteristic feature in elderly patients with hypertrophic cardiomyopathy (HC). Fourteen elderly patients > or = 85 years old (mean age 90 +/- 5 years) with HC were compared with 45 young patients < or = 40 years (mean age 34 +/- 4 years) with this disease. More mild hypertension in the elderly (10/14, 71%) than in the young (0%), and more syncope in the young (10/45, 22%) than in the elderly (0%) were observed. Echocardiography showed that the elderly patients had relatively mild LV wall thickening, generally confined to the septum (elderly vs young: 18 +/- 4 vs 25 +/- 8 mm, p < 0.001), with more basal septal bulging (elderly vs young: 12/14, 86% vs 0%, p < 0.001) and anterior septal hypertrophy of LV (elderly vs young: 11/14, 79% vs 0%, p < 0.001). Elderly patients with mild hypertension showed a predominantly basal septal bulging (10/10, 100%) and anterior septal hypertrophy of LV (9/10, 90%). HC in elderly patients > or = 85 years old has a striking LV morphology. Mild hypertension and advanced age may contribute to the distinctive geometry.

Adult↗

PubMed1998

Partial or complete circular duodenectomy with highly selective vagotomy for severe obstructing duodenal ulcer disease: an initial experience.

OBJECTIVE: To evaluate partial and complete circular duodenectomy combined with highly selective vagotomy (HSV) for relief of gastric retention. DESIGN: A retrospective, case-comparison study. SETTING: University hospital referral center. PATIENTS: Eighteen patients with severe obstructing duodenal ulcer disease defined by failure of a saline load test and endoscopic narrowing of the gastric outlet to 5 mm or less. METHODS: In patients with severe obstructing ulcer the diseased duodenal segment was excised with electrocautery (partial excision, 10 patients; complete excision, 8 patients). An HSV was then done. Postoperative fasting gastric residuum measurement and measurement of the emptying of liquids and solids was done at 3 months and patients were weighed at 3 and 12 months. RESULTS: No patient experienced postoperative gastric retention or required reoperation in a 2-year follow up. The early emptying of liquid (20 minutes) in complete circular duodenectomy plus HSV was more rapid than in normal subjects and duodenal ulcer patients. The emptying of solids was slightly delayed in partial duodenectomy plus HSV compared with duodenal ulcer patients but not with normal controls. The emptying of solids in duodenal ulcer patients was more rapid than in normal controls. Weight gain was excellent at 3 and 12 months. CONCLUSION: Partial duodenectomy and complete circular duodenectomy plus HSV are more efficacious than alternative nonresective procedures in restoring gastric emptying to near normal and restoring weight in patients with obstructing duodenal ulcer.

Duodenal Obstruction↗

PubMed1998

Differential efficacy of passive immunisation against infection by Lyme disease spirochaetes transmitted by partially fed vector ticks.

The efficacy of passive immunisation against tick-transmitted Lyme disease spirochaetal infection was determined in relation to the duration of previous feeding of infected vector ticks. Thus, mice challenged with spirochaete-infected unfed or partially fed nymphal ticks were passively immunised with monoclonal and polyclonal antibodies against the Lyme disease spirochaete (Borrelia burgdorferi) at various intervals after tick attachment. Spirochaetal infection in challenged mice and engorged ticks was verified by xenodiagnosis and indirect immunofluorescent antibody assay, respectively. Although tick-transmitted spirochaetal infection could be aborted by anti-OspA antibodies and hyperimmune antiserum, nearly all immunised mice challenged with infected ticks that had previous 36-h attachment became infected. More than 72% of the nymphal ticks used in this challenge retained their B. burgdorferi infection after engorgement on mice immunised with anti-spirochaete antibodies, and their subsequent infectivity to mice remained effective. It is concluded that a higher efficiency of transmission by partially fed infected nymphs and a lower efficacy of passive immunisation against infection result from an effect of previous feeding of infected ticks that activates antigenic change and enables the spirochaetes to circumvent OspA-based humoral immunity.

Animals↗

PubMed1998

Genospecies identification and characterization of Lyme disease spirochetes of genospecies Borrelia burgdorferi sensu lato isolated from rodents in Taiwan.

Lyme disease spirochetes of the genospecies Borrelia burgdorferi sensu lato were identified and characterized for the first time in Taiwan. Seven isolates, designated TWKM1 to TWKM7, were purified from the ear tissues of three species of rodents captured from seven localities of Taiwan. The immunological characteristics of these Taiwan isolates were compared with those of other genospecies of Lyme disease spirochetes by analyzing the protein profiles and reactivities with B. burgdorferi-specific monoclonal antibodies (MAbs). The genospecies of these Taiwan isolates were also identified by the similarities in their plasmid profiles and differential reactivities with genospecies-specific PCR primers. Although two distinct protein profiles were observed among the seven Taiwan isolates, the MAb reactivities against the outer surface proteins of B. burgdorferi of all of these isolates were consistent with those of B. burgdorferi sensu lato. The similarities of the plasmid profiles also confirmed the identities of these Taiwan isolates. PCR analysis indicated that all of these Taiwan isolates were genetically related to the genospecies B. burgdorferi sensu stricto. These results demonstrate the first identification of Lyme disease spirochetes in Taiwan and also highlight the increasing demand for defining the reservoirs and vector ticks of B. burgdorferi. A serosurvey for Lyme disease infection in the human population of Taiwan may also be required.

Animals↗

PubMed1998

Lyme disease in Taiwan: first human patient with characteristic erythema chronicum migrans skin lesion.

We report herein the first laboratory-diagnosed case of Lyme disease in a human in Taiwan. A 45-year-old Taiwanese man living in Taipei, in northern Taiwan, had an expanding skin lesion (measuring 23 by 15 cm) on his abdomen for 2 to 3 weeks and recurrent attacks of pain and swelling of the knee joint. Serologic tests indicated a significantly elevated titer of antibody to Borrelia burgdorferi. After appropriate antibiotic treatment for 3 weeks, the skin lesion was cured and the joint swelling was improved. Although several strains of Borrelia spirochetes had been isolated from rodents (Rattus losea) in Taiwan, the tick vector responsible for the transmission remains to be identified.

Animals↗

PubMed1998

Ability of azithromycin in combination with quinine for the elimination of babesial infection in humans.

We report the ability of azithromycin in combination with quinine to eliminate the Babesia infection in a native Taiwanese woman. Failure of elimination of the babesial infection was observed two weeks after treating with standard regimen of oral quinine plus intravenous clindamycin for a 10-day course of therapy. Azithromycin in place of clindamycin was administered for another 10-day course of therapy two months following initial treatment. Clearance of Babesia parasites was observed and verified by hamster inoculation. These results suggest that azithromycin plus quinine should be considered as an alternative therapy for human babesiosis, especially in the failure of treatment with standard regimens.

Animals↗

PubMed1998

Lyme disease in Taiwan: primary isolation of Borrelia burgdorferi-like spirochetes from rodents in the Taiwan area.

To investigate the prevalence of Lyme disease infection in Taiwan, we conducted a zoonotic survey for spirochetal infection in the small mammals. Ear tissues of trapped rodents collected from various localities in Taiwan were incubated into BSK-H culture medium and examined for the evidence of spirochetal infection by dark-field microscopy. Spirochetes cultured from six species of wild and peridomestic rodents and seven isolates, designated TWKM 1-7, were purified by serial dilution and membrane filtration. Infection was detected in 16.6% (53 of 320) of captured rodents and the highest infection rate (36.4%) was observed in the brown country rat (Rattus losea, Swinhoe). Higher infection rates based on the geographic distribution were observed in the eastern localities and on Kimmen Island. Reactivity with Borrelia burgdorferi-specific monoclonal antibodies and Western blot analysis indicated that these Taiwan isolates were closely related to the causative agent of Lyme disease, B. burgdorferi sensu lato. These results provide the first evidence of the existence of Lyme disease spirochetes in the Taiwan area.

Animals↗

PubMed1997

Human babesiosis in Taiwan: asymptomatic infection with a Babesia microti-like organism in a Taiwanese woman.

An asymptomatic Babesia infection was confirmed by laboratory diagnoses. The intraerythrocytic protozoan (designed TW1) isolated from a 51-year-old Taiwanese woman appeared to be morphologically consistent with small-form piroplasm, and measurements indicated that it had a body size of 1.5 to 2.5 microm in diameter. The typical features of ring, binary, and tetrad forms were observed in Giemsa-stained thin blood smears. A persistent and low-grade parasitemia was established after hamster inoculation. Indirect immunofluorescent-antibody reactivities indicate that this strain (TW1) of Babesia was serologically related to, but not identical to, the Babesia species (B. microti) that infects rodents. Antibody titers in the patient's sera combined with the clinical symptoms suggested that the present case was a chronic and subclinical babesial infection. A neighborhood human serologic survey indicated that the infection may have been acquired accidentally from an infected rodent and localized within the same family. Indeed, rodents from areas around the neighborhood were trapped, and a high prevalence (83%) of babesial infection was observed. The possible vector responsible for the transmission remains to be identified.

Animals↗

PubMed1996

Accelerated infectivity of tick-transmitted Lyme disease spirochetes to vector ticks.

We determined whether the span of infectivity of Lyme disease spirochetes (Borrelia burgdorferi) to vector ticks varies with the mode of infection in laboratory mice. Noninfected larval deer ticks were permitted to feed on two strains of spirochete-infected mice that had been naturally (via tick bite) and parenterally (via needle injection) infected with B. burgdorferi 2, 4, or 8 weeks earlier, and engorged ticks were dissected and examined for spirochetes by direct immunofluorescence microscopy. After initial infection, spirochetal infectivity to ticks was less efficient in needle-infected mice than in mice infected via tick bites. Tick-transmitted spirochetes develop more rapidly from the skin of infected mice and do not induce a strong antispirochete antibody response during the early stage of infection.

Animals↗

PubMed1995

Differential spirochetal infectivities to vector ticks of mice chronically infected by the agent of Lyme disease.

We determined whether the infectivity of the Lyme disease spirochete (Borrelia burgdorferi) to vector ticks varies with the duration of infection in laboratory mice. Thus, noninfected nymphal deer ticks were permitted to feed on two strains of early (2 months after infection) and late (8 months after infection) spirochete-infected mice. The attached ticks were removed from their hosts at specified time intervals and were thereafter examined for spirochetes by direct immunofluorescence microscopy. Spirochetes can be acquired by nymphal ticks as fast as 8 h after attachment. More than 80% of the attached ticks acquired spirochetal infection within 48 h after feeding on early spirochete-infected mice. In contrast, spirochetal infectivity to ticks was less than 50% after feeding on late spirochete-infected mice. The overall infectivity of spirochete-infected mice to ticks correlated with the duration of tick attachment. In addition, there was no adverse effect on the spirochetal infectivity to ticks by high levels of host antibody against spirochetes, and no obvious differences in infectivity to ticks was observed by the site of tick feeding. We conclude that the span of spirochetal infectivity to ticks varies with the duration of infection in mice and suggest that spirochetes may persist and may be evenly distributed in the skin of infected hosts, regardless of prominent host immunity.

Animals↗

PubMed1995

Effect of ambient temperature on competence of deer ticks as hosts for Lyme disease spirochetes.

We determined whether the temperature of extrinsic incubation affects the competence of vector ticks as hosts for Lyme disease spirochetes (Borrelia burgdorferi). Larval Ixodes dammini ticks that had engorged on spirochete-infected C3H mice were incubated continuously at various temperatures, and the gut contents of the resulting nymphs were examined for spirochetes by direct immunofluorescence microscopy. Spirochetes were present in virtually all nymphs kept at 27 degrees C or less for 6 months, in only 10% of those kept at 33 degrees C, and in none kept at 37 degrees C. Spirochetes became undetectable within 8 weeks when nymphs were warmed from 27 to 33 degrees C beginning at the time of molting. Nymphs became virtually noninfective for mice after incubation at temperatures higher than 27 degrees C for 2 weeks or longer. We conclude that ambient temperatures in excess of 27 degrees C are not permissive for transmission of the agent of Lyme disease.

Animals↗

PubMed1995

Modulation of the trans-suppression activity of hepatitis C virus core protein by phosphorylation.

We previously demonstrated that the core protein of hepatitis C virus (HCV) can suppress gene expression and replication of hepatitis B virus (HBV) in a human hepatoma cell line (HuH-7). In this study, we have characterized the phosphorylation property of HCV core protein and examined the effect of phosphorylation on its suppressive activity of HBV. Our results indicated that both the full-length HCV core protein (22 kDa) and its processed or degraded forms (14 to 18 kDa) were phosphorylated in insect cells. As demonstrated by using the glutathione S-transferase fusion protein expression system and in vitro transcription and translation system, the phosphorylation of HCV core protein was carried out by protein kinase A (PKA) and protein kinase C (PKC) in vitro. In both kinase reactions, it was determined that the phosphorylated amino acid was a serine residue. The potential phosphorylated sites in core protein were identified as residues Ser-53 and Ser-116 for PKA and Ser-53 and Ser-99 for PKC. Comparison of the phosphorylation intensities of the wild type and Ser mutants suggested that Ser-99 and Ser-116 were the major phosphorylation sites for PKC and PKA, respectively. The phosphorylation of Ser-99 and Ser-116, but not Ser-53, in HCV core protein was essential for the suppressive activity of HCV core protein on HBV gene expression and replication in HuH-7 cells. Mutation of the former two serine residues to alanine or aspartate residues led to a drastic loss of the inhibitory effects of HCV core protein on HBV gene expression (both transcription and antigen production) and pregenomic RNA encapsidation, as well as the release of HBV virus particles. In contrast, the Ser-53 mutant conferred the same level of suppressive activity as the wild type did. This property is in accordance with the observation that Ser-99 and Ser-116 are the predominant phosphorylation sites in the HCV core construct. All serine mutants (including those with mutations in PKA, PKC, and both kinase recognition sites) of HCV core protein retained the ability to translocate into the nucleus. Furthermore, wild-type HCV core protein diminished its suppressive activity when cells were treated with PKA or PKC inhibitor. In conclusion, HCV core protein is a phospho-protein and in HuH-7 cells, its trans suppression of HBV gene expression and replication is positively regulated by PKA and PKC. The role of phosphorylation in the control of trans-suppressive activity cannot be reproduced by introducing an acidic residue.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗