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Biomedical subjects

S C Chang

Publications and source records attributed to S C Chang.

At least 127 records · Page 7Linked to original sources
PubMed1999

Biological responses of dog prostate and adjacent structures after meso-tetra-(m-hydroxyphenyl) chlorin and aluminum disulfonated phthalocyanine based photodynamic therapy.

Further to our work on the feasibility of application of photodynamic therapy (PDT) to the canine prostate, this study evaluates the biological responses of the prostate and adjacent vital structures with meso-tetra-(m-hydroxylphenyl) chlorin (mTHPC) or aluminum disulfonated phthalocyanine (AlS2Pc) based PDT as a preparatory step for clinical trials. Skin photosensitivity was not particularly problematic if light protection could be implemented properly for 2 weeks following sensitization. Prostate PDT was well tolerated by the experimental animals with only minor physical distress. mTHPC was more powerful than AlS2Pc in terms of prostate lesions induced. A large portion of prostate tissue could be destroyed by PDT with 4 punctures. Physical distress was probably caused by severe urethral irritation and aching from acute swelling of the prostate. Although the voiding condition normalized within 10 days, regeneration of urethral epithelium was not complete until 3-4 weeks after PDT. Improper placement of laser fiber caused extensive ecchymosis of the retroperitoneal organs. The biological significance of PDT induced hyperemia in the periprostatic structures remains poorly defined. Neither periprostatic nerve damage nor rectal lesions were seen in dogs receiving either mTHPC or AlS2Pc. Glandular atrophy with papillary cystic regeneration of the prostate was the most prominent finding 90 days after PDT. The glandular architecture was well preserved because the interlobular collagens were less affected than the cellular components of the glands. Our study suggests that PDT with mTHPC and AlS2Pc is safe and promising for necrosing a substantial amount of prostate tissue. The completeness of treatment and long-term therapeutic effectiveness for prostate cancer, however, remains to be determined through further investigation.

Animals↗
PubMed1999

Imported malaria: successful treatment of 31 patients in the era of chloroquine resistance.

The diagnosis and management of imported malaria presents a continuing challenge in developed countries, including Taiwan. We retrospectively analyzed the records of all 31 patients with imported malaria treated at National Taiwan University Hospital from January 1984 through December 1998. Plasmodium falciparum was identified as the causative malarial parasite in 18 patients, P. vivax in 12, and P. ovale in one. All 31 patients had fever, but only 13 presented with the characteristic fever pattern. The most common initial laboratory abnormalities were thrombocytopenia (20/31), mild hyperbilirubinemia (20/31), and leukopenia (7/31). The median time from the onset of fever to the correct diagnosis was 4 days for P. falciparum and 5 days for P. vivax. In 28 cases, the clue that led to early diagnosis was the patient's travel history. Quinine, but not chloroquine, was effective in 17 out of 18 cases of falciparum malaria. Three patients treated with intravenous quinine required a change of regimen because of life-threatening quinine toxicity; artesunate served as a safe and effective alternative in this situation. While most patients with tertian malaria were cured with the standard chloroquine and primaquine regimen, a higher dosage was required for one case acquired in Papua New Guinea. All patients, including two with severe malaria, survived. We conclude that, the mortality of imported malaria in the chloroquine resistance era can be minimized with early recognition by obtaining a thorough travel history, and instituting appropriate antimalarial chemotherapy based on precise identification of species. Quinine toxicity should be closely monitoried, especially when this drug is given intravenously.

Adolescent↗
PubMed1999

Maxillary growth after palatal denudation: an animal experiment.

BACKGROUND: Palate surgery at an early age may cause retardation of maxillary growth. The second intention healing of the raw bone surface created on the palate is considered to be the cause of the growth retardation. The animal experiment in this study was designed to evaluate this effect. METHODS: Four-week-old Sprague-Dawley rats were divided into 3 groups. In the first group, a strip of mucoperiosteum was excised on both sides of the hard palate. A second group of rats received a sham surgery in which bilateral mucoperiosteal flaps were raised and redraped. The third group served as controls with no surgery. Flap elevation with and without excision was performed under an operative microscope to facilitate the delicate manipulation of tissue and to avoid injury to the underlying bone. The animals were killed 11 weeks later and the skulls were prepared for measurements, which included the palatal inter-molar width, maxillary height, and maxillary length. RESULTS: The results revealed statistically significant decreases in palatal width and maxillary length in the experimental group (excision of mucoperiosteum). No differences were observed in the vertical height of the maxilla. CONCLUSION: This study confirms that surgically created bone denudation of the palate causes maxillary growth disturbances.

Animals↗
PubMed1999

Spontaneous multiple cholecystoenteric fistulas--a case report.

Spontaneous multiple cholecystoenteric fistulas are relatively rare complications of chronic cholecystitis. One cholecystoduodenal and two cholecystocolonic fistulas were observed in a 65-year-old woman whose symptoms included fever, chills, jaundice, diarrhea, and prolonged right upper quadrant pain. Pneumobilia, which is a pathognomonic sign of bilioenteric fistula, was also detected by her plain abdomen X-ray on admission. Both types of fistulas were correctly diagnosed preoperatively by barium enema, upper GI series and endoscopic retrograde cholangiopancreaticography. The patient was referred for surgery and fistulas were identified during laparotomy. Cholecystectomy, division of these fistulas, and primary repair of these bowel defects were successfully performed. The postoperative course was unremarkable. We report this unusual case and briefly review the hypothesized pathogenesis, typical symptomatology, radiographic diagnosis, complications and therapeutic modalities of this condition.

Aged↗
PubMed1999

Necrotizing fasciitis caused by Serratia marcescens in two patients receiving corticosteroid therapy.

Necrotizing fasciitis (NF), a devastating soft tissue infection, is rarely attributed to Serratia marcescens. We here report two patients with S. marcescens NF, both of whom had underlying renal disease and had been receiving corticosteroid therapy. The first patient, a 40-year-old man with systemic lupus erythematosus and uremia on prednisolone therapy, developed fulminant cellulitis and septic shock 1 month after a skin biopsy for cutaneous vasculitis of the left foot. The cellulitis evolved to NF, and blood and necrotic tissue cultures both grew S. marcescens. The patient completely recovered after debridement and ceftazidime therapy. The second patient, a 73-year-old man receiving prednisolone therapy for nephrotic syndrome, developed right leg cellulitis that evolved to NF. Blood and necrotic tissue cultures both grew S. marcescens. After aggressive debridement and ciprofloaxcin therapy, the NF improved. However, the patient died of aspiration pneumonia and massive gastrointestinal bleeding 1 month later. These findings illustrate that S. marcescens should be considered as a potential pathogen causing NF in susceptible hosts.

Adult↗
PubMed1999

Penicillin-nonsusceptible Streptococcus pneumoniae infections in children.

The emergence of penicillin-nonsusceptible Streptococcus pneumoniae (PNSSP) has brought a new clinical challenge. In Taiwan, reports of the prevalence and clinical features of PNSSP infections in children are limited. This study reviewed the resistance patterns of all clinical isolates of S. pneumoniae obtained from patients under 17 years of age from January 1993 through July 1998 in a medical center. Their clinical features and treatment responses were analyzed, with special attention paid to those patients with invasive PNSSP infections. Totally, 170 clinical isolates of S. pneumoniae were obtained from 168 patients aged under 17 years. Among those infections, there were 56 sinusitis (including 4 sinusitis with bacteremia), 44 pneumonia (including 23 pneumonia with bacteremia or empyema), 23 otitis media (including 5 otitis media with bacteremia), 9 simple bacteremia, 9 conjunctivitis, 8 meningitis, 4 peritonitis, 3 skin infections and the other 14 isolates were colonization. One hundred eleven isolates (65.3%) showed reduced penicillin susceptibility by the disk diffusion method. A trend of increasing percentiles of PRSP was noted: 27.3% (3/11) in 1993, 37.5% (9/24) in 1994, 55.5% (10/18) in 1995, 77.5% (31/40) in 1996, 66.0% (31/47) in 1997, and 87.1% (27/31) in 1998. Minimum inhibitory concentration (MIC) determinations by the E-test showed some of the isolates were intermediately resistant. Prior antibiotic usage was associated with a higher incidence of PNSSP infections. However, most children responded well to antimicrobial treatment.

Adolescent↗
PubMed1999

Different dietary fats influence serum and tissue lipids and anti-cardiolipin antibody levels in autoimmune-prone NZB/W F1 mice.

To investigate the influence of different dietary fats on lipids and anti-cardiolipin antibody levels, autoimmune NZB/W F1 mice were fed on diets containing 200 g dietary fat as palm oil, lard-soyabean oil (1:1, w/w), soyabean oil, rapeseed oil or fish oil/kg. In addition, each dietary fat group was divided into an early-feeding group with feeding from 2 months of age, and a late-feeding group with feeding from 5 months of age. Serum levels of triacylglycerol, phospholipid, cholesterol and anti-cardiolipin antibody were measured at regular intervals, and mice were killed at the age of 7 months for analysis of hepatic lipid and fatty acids. The results showed that hepatic triacylglycerol and cholesterol contents were lower in mice fed on fish oil than in those fed on palm oil. In contrast, hepatic phospholipid content was higher in mice of the fish oil group than in those of the other four dietary fat groups. Composition profiles for both hepatic and renal oleic acid (18: 1n-9), linoleic acid (18: 2n-6) and eicosapentaenoic acid (20: 5n-3) were similar to those of the dietary fats in mice of both early-feeding and late-feeding groups. Fish oil intake decreased arachidonic acid (20: 4n-6) concentration in kidney tissue but not in liver tissue. Serum triacylglycerol, cholesterol and phospholipid levels were lower in mice fed on fish oil than in those fed on palm oil. Immunoglobulin (Ig) M anti-cardiolipin antibody was lower for the fish oil group than for the other groups. The IgG anti-cardiolipin antibody level was significantly lower in mice fed on fish oil compared with that of the palm oil group only in the early-feeding group. There was a positive correlation between serum IgM anti-cardiolipin antibody and phospholipid levels (early-feeding group r 0.902, P < 0.05; late-feeding group r 0.894, P < 0.05). These findings suggest dietary fish oil may affect both lipid levels and anti-cardiolipin antibody, contributing to alleviation of the autoimmune process in autoimmune-prone NZB x NZW F1 mice.

Analysis of Variance↗
PubMed1999

[Vancomycin-resistant enterococci in north-eastern Taiwan].

Vancomycin-resistant enterococci (VRE) is a world-wide emerging pathogen. The first confirmed VRE isolate in Taiwan was detected in 1995. After that, more and more isolates of VRE were found in western part of Taiwan. However, before this report, there was no any isolate of VRE found in eastern part of Taiwan. In December 1997 and January 1998, two cases of VRE urinary tract infection were found in two regional hospitals in north-eastern Taiwan. They had received prolonged treatment with multiple antibiotics for other infections before they got VRE infection. The isolates showed susceptibility to other antimicrobial agents by routine disk diffusion susceptibility test and these two patients were successfully treated. The VRE did not spread in those two hospitals. After further study, the 3 isolates from these two patients all had minimum inhibitory concentration of vancomycin >256 microg/mL. They all carried van A gene and the pulsed-field gel electrophoresis demonstrated they belonged to different DNA types. It was concluded that VRE appeared in north-eastern Taiwan but the strains were not from a common source.

Aged↗
PubMed1998

Clinical features and outcome in disseminated mycobacterial diseases in AIDS patients in Taiwan.

OBJECTIVE: To describe and compare the clinical features and outcome of disseminated tuberculosis (TB) and Mycobacterium avium complex (MAC) disease in AIDS patients. DESIGN: Prospective cohort study. SETTING: A 1800-bed university teaching hospital, the largest centre for HIV/AIDS patients in Taiwan. METHODS: From July 1994 through June 1997, a standardized protocol was used to record the demographic and clinical features in all hospitalized HIV-infected patients, and to perform routine studies and invasive procedures for diagnosis of disseminated mycobacterial diseases. To compare the survival, control patients were selected from the HIV-infected patients hospitalized in the same hospital during the same study period, and had similar age, sex, CD4+ cell counts and antiretroviral therapy regimens. RESULTS: A total of 22 cases of disseminated TB and 15 cases of disseminated MAC were identified. Disseminated TB and MAC occurred in patients with similarly low CD4+ cell counts (median, 23 versus 5 x 10(6)/l; P = 0.08). The clinical features favouring disseminated TB included night sweats, peripheral lymphadenopathy, acid-fast bacilli in sputum smears, chest radiographic findings of hilar enlargement, and lack of prior AIDS-defining illnesses. Hepatosplenomegaly, elevated serum alkaline phosphatase (more than twice the upper limit of normal), elevated serum gamma-glutamyl transpeptidase (more than three times the upper limit of normal), and leukopenia favoured disseminated MAC. The patients with disseminated TB survived much longer than patients with disseminated MAC (mean survival, 96 versus 22 weeks, P = 0.008) but had a similar outcome to control patients (P = 0.60). CONCLUSION: Disseminated TB and MAC are distinguishable by clinical features in AIDS patients with similar immunocompromised states. Those features may facilitate diagnosis and selection of specific therapeutic regimens. Disseminated TB was not associated with a shortened survival period in AIDS patients when they completed anti-TB treatment. In contrast, disseminated DMAC was associated with shortened survival despite treatment with potent regimens. These results may emphasize the importance of prophylaxis for MAC in this population.

AIDS-Related Opportunistic Infections↗
PubMed1998

Isolation and characterization of the gene (CLS1) encoding cardiolipin synthase in Saccharomyces cerevisiae.

In eukaryotic cells, cardiolipin (CL) synthase catalyzes the final step in the synthesis of CL from phosphatidylglycerol and CDP-diacylglycerol. CL and its synthesis are localized predominantly to the mitochondrial inner membrane, and CL is generally thought to be an essential component of many mitochondrial processes. By using homology searches for genes potentially encoding phospholipid biosynthetic enzymes, we have cloned the gene (CLS1) encoding CL synthase in Saccharomyces cerevisiae. Overexpression of the CLS1 gene under its endogenous promoter or the inducible GAL1 promoter in yeast and expression of CLS1 in baculovirus-infected insect cells resulted in elevated CL synthase activity. Disruption of the CLS1 gene in a haploid yeast strain resulted in the loss of CL synthase activity, no detectable CL, a 5-fold elevation in phosphatidylglycerol levels, and lack of staining of mitochondria by a dye with high affinity for CL. The cls1::TRP1 null mutant grew on both fermentable and non-fermentable carbon sources but more poorly on the latter. The level and activity of cytochrome c oxidase was normal, and a dye whose accumulation is dependent on membrane proton electrochemical potential effectively stained the mitochondria. These results definitively identify the gene encoding the CL synthase of yeast.

Amino Acid Sequence↗
PubMed1998

The PEL1 gene (renamed PGS1) encodes the phosphatidylglycero-phosphate synthase of Saccharomyces cerevisiae.

Phosphatidylglycerophosphate (PG-P) synthase catalyzes the synthesis of PG-P from CDP-diacylglycerol and sn-glycerol 3-phosphate and functions as the committed and rate-limiting step in the biosynthesis of cardiolipin (CL). In eukaryotic cells, CL is found predominantly in the inner mitochondrial membrane and is generally thought to be an essential component of many mitochondrial functions. We have determined that the PEL1 gene (now renamed PGS1), previously proposed to encode a second phosphatidylserine synthase of yeast (Janitor, M., Jarosch, E., Schweyen, R. J., and Subik, J. (1995) Yeast 13, 1223-1231), in fact encodes a PG-P synthase of Saccharomyces cerevisiae. Overexpression of the PGS1 gene product under the inducible GAL1 promoter resulted in a 14-fold increase in in vitro PG-P synthase activity. Disruption of the PGS1 gene in a haploid strain of yeast did not lead to a loss of viability but did result in a dependence on a fermentable carbon source for growth, a temperature sensitivity for growth, and a petite lethal phenotype. The pgs1 null mutant exhibited no detectable in vitro PG-P synthase activity and no detectable CL or phosphatidylglycerol (PG); significant CL synthase activity was still present. The growth arrest phenotype and lack of PG-P synthase activity of a pgsA null allele of Escherichia coli was corrected by an N-terminal truncated derivative of the yeast PG-P synthase. These results unequivocally demonstrate that the PGS1 gene encodes the major PG-P synthase of yeast and that neither PG nor CL are absolutely essential for cell viability but may be important for normal mitochondrial function.

Amino Acid Sequence↗
PubMed1998

The nucleolin binding activity of hepatitis delta antigen is associated with nucleolus targeting.

Hepatitis delta antigens (HDAgs) are important for the replication and assembly of hepatitis delta virus (HDV). To understand the association between HDAgs and cellular proteins and the mechanism of viral multiplication, we have studied the interaction between HDAgs and nucleolin, a major nucleolar phosphoprotein. The interaction between HDAgs and nucleolin was first demonstrated by immunofluorescence staining studies. HDAgs and endogenous nucleolin were colocalized in the nucleoli of cultured cells transfected with plasmids encoding the small and large HDAg. Coimmunoprecipitation results indicated that the NH2-terminal domain of HDAg was essential for its binding to nucleolin. In vitro ligand binding assays revealed two nucleolin binding sites, NBS1 and NBS2. Each spanned amino acid residues 35-50 and 51-65, respectively, with a conserved core sequence K(K/R)XK. HDV replication was modulated by exogenous human nucleolin. In addition, a small HDAg mutant S-d65/75, which possesses both NBS1 and NBS2, was capable of transactivating HDV replication, whereas the small HDAg mutant S-d50/75, which retained NBS1 but not NBS2, was unable to support the replication of HDV. Thus, the nucleolin binding activity of HDAg is critical for its nucleolar targeting and is involved in the modulation of HDV replication.

Animals↗
PubMed1998

The inhibitory effect of common traditional anti-rheumatic herb formulas on prostaglandin E and interleukin 2 in vitro: a comparative study with Tripterygium wilfordii.

To understand the clinical efficacy of traditional anti-rheumatic herbal medicines on acute and severe arthritis or immune diseases, four herbal formulas and one herb were tested in vitro to determine their effects on prostaglandin E2 (PGE2) and interleukin 2 (IL2). Peripheral blood mononuclear cells from healthy subjects were incubated with different concentrations of four herbal formulas including Shaur Yau Gan Tsao Tang (SYGTT), Shang Jong Shiah Tong Yong Tong Feng Wan (SJSTY), Shu Jin Lih An Saan (SJLAS), Ma Shing Yih Gan Tang (MSYGT) and one herb, Tripterygium wilfordii (T2) with and without mitogen stimulation. PGE2 and IL2 from culture supernatant were measured by enzyme immunoassay. The results showed that SYGTT, SJSTY, SJLAS at concentration of 100 microg and MSYGT at 500 microg/ml can significantly inhibit PGE2 release (P < 0.05) from mononuclear cells. However, T2 at 2 microg/ml expressed the same response. For the inhibition of IL2, the concentration of SYGTT, SJSTY and SJLAS must exceed 100 symbol microg/ml. MSYGT failed to inhibit IL2 at even concentrations of 500 microg/ml but T2 at a very low concentration (0.6 microg/ml) could strongly inhibit it. The findings suggest that the majority of traditional anti-rheumatic herbal formulas or herbs, except for T2, should not be used to treat acute and critical arthritis or immune diseases.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Emphysematous prostatic abscess due to Klebsiella pneumoniae.

Prostatic abscess is an unusual occurrence in the era of modern antibiotics. We report a rare case of emphysematous prostatic abscess owing to Klebsiella pneumoniae in a 45-year-old man with a 10-year history of alcoholism and a 6-year history of diabetes mellitus. Prostatic abscess is a difficult clinical diagnosis without specific symptoms and signs. Computerized tomography can assist in making the diagnosis of emphysematous prostatic abscess. Definitive treatment is complete surgical drainage and the use of effective antibiotics.

Abscess↗
PubMed1998

In vitro activity of meropenem against common pathogenic bacteria isolated in Taiwan.

The in vitro antimicrobial activity of meropenem, in comparison with nine other antimicrobial agents, against 12 different common pathogenic bacteria were evaluated to know the susceptibility of common bacteria to meropenem in Taiwan. Meropenem was active against most Gram-positive, Gram-negative, and anaerobic bacteria, including methicillin-sensitive Staphylococcus aureus, Streptococcus pyogenes, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Burkholderia cepacia, Acinetobacter baumannii, Haemophilus influenzae, and Bacteroides fragilis. For many of them, meropenem was the most active one in comparison with other broad-spectrum cephalosporins, aztreonam, imipenem, and ciprofloxacin. It is concluded that meropenem is a very active agent against most common pathogenic bacteria. It is uncommon for these common bacteria, except MRSA and Stenotrophomonas maltophilia, to be resistant to meropenem in Taiwan, where a high prevalence of resistance to other antimicrobial agents was found in many of the common bacteria.

Anti-Bacterial Agents↗
PubMed1998

Efficacy and safety of cefepime treatment in Chinese patients with severe bacterial infections: in comparison with ceftazidime treatment.

An open label, randomized comparative study was conducted to evaluate the safety and efficacy of cefepime, in comparison with ceftazidime, in the treatment of adult hospitalized Chinese patients with severe bacterial infections. Forty patients with severe infections including septicemia, urinary tract infection and bacterial pneumonia were randomly assigned to receive treatment with cefepime (2 g intravenously every 12 h) or ceftazidime (2 g intravenously every 8 h). The cefepime group (20 evaluable patients) and ceftazidime group (16 evaluable patients) were comparable with respect to age, sex, underlying diseases and distribution of infection type. In both groups urinary tract infection was the most common type of infection and Escherichia coli was the most common etiologic microorganism. The rates of satisfactory clinical response were similar in the cefepime and ceftazidime groups (95 versus 93.7%; 95% confidence interval: -0.14 - 0.17, P = 0.87). The bacteriological response rates of the cefepime and ceftazidime groups did not differ significantly (88.9 versus 85.7%; 95% confidence interval: -0.30 - 0.36, P = 0.85). Both cefepime and ceftazidime were well tolerated, with similar incidence of side effects. The results of this study suggest that cefepime is as safe and effective as ceftazidime for the treatment of serious infections in adult hospitalized Chinese patients.

Asian People↗
PubMed1998

A novel spliced transcript of influenza A/WSN/33 virus.

It has been shown that influenza A virus M1 mRNA has two alternative 5" splice sites: a distal 5" splice site producing M3 mRNA that has the coding potential for 9 amino acids and a proximal 5" splice site producing M2 mRNA that encodes the essential M2 ion-channel protein. In this study, we demonstrated that the laboratory widely used strain A/WSN/33, but not A/Udorn/72 possessed another novel 5" splice site producing a transcript with the coding potential for 54 amino acids. We nominated this novel transcript as M4 mRNA. M4 mRNA was detected in A/WSN/33-infected cells derived from different species. Sequence comparison of M1 mRNA in both A/WSN/33 and Udorn/72 at position 143 to 151 reveals that this novel 5" splice site generated in WSN was due to one nucleotide difference at position 147. Several strains of influenza A viruses other than WSN also possess the potential M4 5" splice site by sequence analysis from the files of GenBank.

Alternative Splicing↗