Biomedical subjects

C Y Chan

Publications and source records attributed to C Y Chan.

At least 55 records · Page 3Linked to original sources

PubMed1999

A randomized, double-blind, controlled trial of consensus interferon in the treatment of Chinese patients with chronic hepatitis C.

OBJECTIVE: Patients with chronic hepatitis C virus (HCV) infection have an increased risk of developing cirrhosis or hepatocellular carcinoma. Consensus interferon (CIFN) offers sustained clinical efficacy to patients studied in the Western countries. This randomized, double-blind, controlled trial in 75 Chinese patients with chronic hepatitis C compared treatment with CIFN or placebo to determine whether CIFN had efficacy and safety in Chinese patients similar to that in Western patients. METHODS: Patients were randomized to receive CIFN (3 microg or 9 microg) or placebo given subcutaneously 3 times/wk for 24 wk, followed by 24 wk of observation. Efficacy was assessed by normalization of serum alanine transaminase (ALT) and clearance of serum HCV RNA concentrations to undetectable levels by reverse-transcription polymerase chain reaction. RESULTS: There was a greater benefit with CIFN 9 microg than with CIFN 3 microg or placebo. At the end of 24 wk of treatment, the ALT response was 64%, 38.5%, and 8.4% for the 9-microg, 3-microg, and placebo-treated groups, respectively. After an additional 24 wk of observation, sustained ALT responses were 44%, 23.1%, and 12.5% for the 9-microg, 3-microg, and placebo-treated groups, respectively. HCV RNA clearance at the end of treatment was 56%, 42.3%, and 4.2%; and after 24 wk of additional observation, 40%, 11.5%, and 0% for the 9-microg, 3-microg, and placebo-treated groups, respectively. There were no unexpected adverse reactions to CIFN. CONCLUSIONS: The results show that administration of CIFN subcutaneously at 9 microg 3 times a week is safe and can effectively reduce serum ALT and HCV RNA concentrations in Chinese patients with chronic hepatitis C.

Antiviral Agents↗

PubMed1999

Permanent anatomic closure of the ductus arteriosus in newborn baboons: the roles of postnatal constriction, hypoxia, and gestation.

Permanent closure of the ductus arteriosus requires loss of cells from the muscle media and development of neointimal mounds, composed in part of proliferating endothelial cells. We hypothesized that postnatal ductus constriction produces hypoxia of the inner vessel wall; we also hypothesized that hypoxia might lead to cell death and the production of vascular endothelial cell growth factor (VEGF), a hypoxia-inducible growth factor that stimulates endothelial proliferation. We mapped the distribution of hypoxia in newborn baboons and correlated it with the appearance of cell death (TUNEL technique), VEGF expression, and endothelial proliferation (proliferating cell nuclear antigen expression). In the full-term baboon (n=10), the ductus was functionally closed on Doppler examination by 24 h after delivery. Regions of the ductus where the lumen was most constricted were associated with moderate/intense hypoxia; VEGF expression was increased in the hypoxic muscle media, and luminal endothelial cells, adjacent to the hypoxic media, were proliferating. Cells in the most hypoxic regions of the ductus wall were undergoing DNA fragmentation. In contrast, regions of the ductus with mild degrees of hypoxia had no evidence of cell death, VEGF expression, or endothelial proliferation. Cell death and endothelial proliferation seemed to be limited to regions of the full-term ductus experiencing moderate/intense hypoxia. In the premature baboon (67% gestation) (n=24), only 29% closed their ductus by Doppler examination before d 6. None of the premature baboons, including those with a closed ductus by Doppler, had evidence of moderate/intense hypoxia; also, there was no evidence of cell death, VEGF expression, endothelial proliferation, or neointima formation by d 6. Therefore, the premature ductus is resistant to developing hypoxia, even when its lumen is constricted; this may make it susceptible to later reopening.

Animals↗

PubMed1999

Serum levels of cytokines in hepatitis C-related liver disease: a longitudinal study.

BACKGROUND: Elevated serum cytokine levels are found in patients with acute and chronic hepatitis B. However, little is known about the development and progression of cytokines in hepatitis C infection. We conducted this study to evaluate the change and clinical significance of cytokines in the different stages of hepatitis C infection. METHODS: Circulating interleukin-1 beta (IL-1 beta), interleukin-2 receptor (IL-2r), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were measured by enzyme-linked immunosorbent assay in 29 patients with acute hepatitis C (AHC), 43 patients with chronic hepatitis C (CHC), 40 patients with liver cirrhosis (LC) and positive serum anti-hepatitis C antibody (anti-HCV), 36 patients with hepatocellular carcinoma (HCC) and positive anti-HCV and 30 normal controls. A cohort of patients with chronic hepatitis C was monitored for a median of seven years. RESULTS: Serum IL-1 beta, IL-2r, IL-6 and TNF-alpha levels were significantly elevated in all patient groups compared with controls (p < 0.05). The serum IL-1 beta, IL-2r and TNF-alpha levels in patients with LC or HCC were higher than that in patients with AHC or CHC (p < 0.05). In the longitudinal follow-up, 12 patients with chronic hepatitis at enrollment in the study developed liver cirrhosis. For these patients, serum levels of IL-1 alpha, IL-2r and TNF-alpha were higher in liver cirrhosis than in chronic hepatitis (p < 0.05). In addition, the serum concentrations of these cytokines correlated better with indices of hepatic dysfunction (prothrombin time and indocyanine green retention ratio) than with parameters of hepatic inflammation (alanine aminotransferase and aspartate aminotransferase). CONCLUSIONS: Serum IL-1 beta, IL-2r, IL-6 and TNF-alpha levels are elevated in patients with hepatitis C-related liver diseases, especially in LC and HCC patients. These levels reflect hepatic dysfunction better than liver inflammation parameters, which might explain the higher serum concentrations of cytokines in LC patients.

Adult↗

PubMed1999

Report of eight cases of pulmonary actinomycosis and their treatment with imipenem-cilastatin.

Studies on the efficacy of antimicrobial agents against actinomycosis in vivo have been limited apart from those involving penicillin. A prospective ministudy on the efficacy of imipenem-cilastatin in the treatment of pulmonary actinomycosis was performed based on preliminary encouraging in vitro and in vivo data. Eight patients were diagnosed as having pulmonary actinomycosis using fibreoptic bronchoscopy (7) and percutaneous transthoracic needle biopsy (1) in the authors' unit between 1994 and 1996. Each patient received a 4-week course of imipenem-cilastatin that comprised 2 weeks of intravenously administered drug (500 mg at 8-hourly intervals) and 2 weeks of intramuscularly administered drug (500 mg at 12-hourly intervals). Seven patients showed a very good clinical and radiographic response as well as bronchoscopically-documented treatment success. Treatment failed in one patient. Amongst the former group, one patient was lost to follow-up, another relapsed 3 months after treatment cessation and the rest remained relapse-free when followed-up for 18-44 months (mean 30.2 months). Furthermore, all patients showed good clinical tolerance and no abnormal treatment-related laboratory findings. The favourable outcome for most patients in this mini-study suggest that a 4-week parenteral course of imipenem-cilastatin is an efficacious treatment for pulmonary actinomycosis. This antimicrobial regimen might be a promising alternative to the time-honoured long-course treatment with intravenous and oral penicillin.

Actinomycosis↗

PubMed1999

The prognostic significance of p16INK4a/p14ARF and p15INK4b deletions in adult acute lymphoblastic leukemia.

Cytogenetic/molecular abnormalities significantly influence the prognosis of patients with acute leukemia. Recently, two genes, p16INK4a and p15INK4b, encoding two cyclin-dependent kinase inhibitor proteins of the INK4 family of Mr 15,000 and 16,000, respectively, have been localized to 9p21. Remarkably, the p16INK4a locus has been found to encode a second protein, p14ARF, known as p19ARF in mice, with a distinct reading frame. Like p16INK4a, p14ARF is involved in cell cycle regulation, blocking cells at the G1 restriction point through the activity of MDM-2 and p53. We studied bone marrow samples of 42 newly diagnosed and untreated patients with acute lymphoblastic leukemia for the incidence of deletions of p16INK4a/p14ARF and p15INK4b using Southern blot analysis and determined the clinical outcome with regard to complete remission (CR) duration, event-free survival, and overall survival. We found deletions of p16INK4a/p14ARF in 17 of 42 patients (40%), with homozygous deletions in 11 of 42 patients (26%) and hemizygous deletions in 6 of 42 patients (14%). The gene for p15INK4b was codeleted in most, but not all, cases and was never deleted without deletion of p16INK4a/ p14ARF. No correlation was observed between molecular studies and karyotype abnormalities as determined by conventional cytogenetics. Furthermore, no difference was found in the CR rate, CR duration, event-free survival, and overall survival in patients with homozygous gene deletions compared to patients with no deletions or loss of only one allele.

Adolescent↗

PubMed1999

A two dose combined hepatitis A and B vaccine in Chinese youngsters.

This open, randomized study was conducted in healthy Chinese youngsters, aged between 10 and 19 years to compare the reactogenicity and immunogenicity of two vaccines: the combined vaccine against hepatitis A and B was administered in a two-dose schedule with the profile of the corresponding monovalent vaccines, while the concomitant vaccine was administered also on a two-dose schedule but simultaneously in opposite arms. All vaccinees had antibodies against hepatitis A (anti-HAV) after the 2-dose administration, whereas all but four in the first and two in the second group had protective titres against hepatitis B (anti-HBs). At month 7, the geometric mean titres for both antibodies were more than double for the group of subjects receiving the combined vaccine: 3,701 vs. 1,705 mIU/ml for the anti-HAV, and 1,524 vs. 720 mIU/ ml for the anti-HBs response. Injection site pain was the most commonly reported local symptom and headache was the most reported general symptom. It is concluded that this combined vaccine against hepatitis A and B, administered according to a two-dose schedule, is well-tolerated and highly immunogenic.

Adolescent↗

PubMed1999

Circulating intercellular adhesion molecule-1 in chronic liver disease and hepatocellular carcinoma.

BACKGROUND: Intercellular adhesion molecule-1 (ICAM-1) is important in the migration and adhesion of immune cells from the circulation to their targets. A circulating form of ICAM-1 (cICAM-1) is elevated in the serum of patients with hepatitis and various cancers. Our aim was to determine the clinical significance of cICAM-1 in chronic liver diseases and hepatocellular carcinoma (HCC). METHODS: We measured the serum cICAM-1 levels in 91 patients with HCC, 47 with liver cirrhosis, 41 with chronic viral hepatitis and 32 healthy controls using an enzyme-linked immunosorbent assay. Ninety-eight patients had serial follow-up. RESULTS: The cICAM-1 levels in patients with HCC (737 +/- 212 ng/ml) and liver cirrhosis (593 +/- 145 ng/ml) were significantly higher than those in patients with chronic viral hepatitis (488 +/- 127 ng/ml) and controls (318 +/- 64 ng/ml). HCC patients had higher cICAM-1 levels than all the other groups. cICAM-1 levels in patients with chronic viral hepatitis correlated with serum alanine aminotransferase, prothrombin time and indocyanine green retention ratio. In HCC patients, alpha-fetoprotein levels and tumor size paralleled cICAM-1 concentrations. Furthermore, HCC patients with distant metastases had higher cICAM-1 levels than those without distant metastases, and levels of cICAM-1 in patients with stage IV HCC were higher than those in HCC patients with stages I, II or III disease. During a seven-year follow-up, 14 patients with chronic hepatitis developed liver cirrhosis when their cICAM-1 levels increased significantly. In 47 HCC patients, cICAM-1 levels decreased after tumor resection or transcatheter arterial embolization, and increased when the tumor recurred. cICAM-1 levels increased gradually in 14 patients with advanced HCC without specific therapy. CONCLUSIONS: CICAM-1 levels are increased in patients with chronic hepatitis, liver cirrhosis and HCC. This reflects the severity and progression of chronic liver disease and HCC. Sequential measurements of cICAM-1 seem more valuable than a single-point assessment in evaluating the progress of liver disease.

Adult↗

PubMed1999

Hepatitis B vaccination in patients with chronic hepatitis C.

The aim of the study was to evaluate the safety, immunogenicity, and possible therapeutic effect of hepatitis B vaccine in patients with chronic hepatitis C. The subjects studied included three groups: group I, 26 patients with chronic hepatitis C who were susceptible to hepatitis B virus infection; group II, 35 healthy subjects who were susceptible to both hepatitis B and hepatitis C virus infection; and group III, 30 patients with chronic hepatitis C receiving no hepatitis B vaccination as controls. Three 20 microg/dose of recombinant hepatitis B vaccines were given to subjects of groups I and II in months 0, 1, and 6. Blood samples from the subjects were collected before and 1 month after each dose of vaccination for serological testing. The subjects of groups I and II had similar antibody to hepatitis B surface antigen (anti-HBs) response rates after the first (30.8% vs. 17.1%), second (61.5% vs. 60.0%), and third (88.5% vs. 91.4%) doses of vaccination. Also, their geometric mean titers of anti-HBs did not differ much when vaccination completed in 7 months (360 vs. 581 mIU/ml). During vaccination period, patients with chronic hepatitis C demonstrated no significant change of serum cytokines and HCV RNA levels, but significantly lowered ALT levels after three doses of vaccination. Hepatitis B vaccination is safe and immunogenic in patients with chronic hepatitis C. It did not significantly affect their levels of HCV RNA, but tended to lower ALT levels.

Adolescent↗

PubMed1999

Serum pharmacokinetics of antimycobacterial drugs in patients with multidrug-resistant tuberculosis during therapy.

Serum samples of 13 patients with multidrug-resistant tuberculosis were taken 0, 1, 2, 4, 8 h after administration of antimycobacterial drugs for assay of levels in order to gain further insight into their basic pharmacokinetics. The drugs assessed were amikacin, kanamycin, ofloxacin, levofloxacin, para-aminosalicylic acid, prothionamide, cycloserine, pyrazinamide and ethambutol. Techniques used for assay were reversephase high-performance liquid chromatography, gas liquid chromatography and fluorescent polarization immunoassay. The results from 12 patients were evaluated. These provided new pharmacokinetic data on high-dose levofloxacin, cycloserine and prothionamide given once daily, and could be useful in guiding the scheduling of drugs. The data obtained might also lead to insights into the development of therapeutic drug monitoring in multidrug-resistant tuberculosis.

Adult↗

PubMed1999

Detection of antibodies to E2-protein of GB virus-C/hepatitis G virus in patients with acute posttransfusion hepatitis.

GB virus-C/hepatitis G virus (GBV-C/HGV) is an RNA virus that can be transmitted by transfusion with the diagnosis based on the detection of serum GBV-C/HGV RNA by reverse transcription-polymerase chain reaction. In order to evaluate the role of antibodies to the E2 protein (anti-E2) of GBV-C/HGV in patients with acute posttransfusion hepatitis, anti-E2 was measured in one patient with acute GBV-C/HGV infection, five patients with acute GBV-C/HGV and hepatitis C virus (HCV) coinfection, and four patients with positive pretransfusion GBV-C/HGV RNA who were superinfected with HCV after transfusion. One patient with acute GBV-C/HGV infection remained GBV-C/HGV RNA-positive 18 months after transfusion and did not develop anti-E2. Among five patients with acute GBV-C/HGV and HCV coinfection, one lost GBV-C/HGV RNA 28 months after transfusion and developed anti-E2 independent of serum alanine aminotransferase levels. The other four patients remained GBV-C/HGV RNA-positive and anti-E2-negative at the end of follow-up. Among four patients with positive pretransfusion GBV-C/HGV RNA and super-infected with HCV, one lost GBV-C/HGV RNA 2 months and one 10 months after superinfection and subsequently developed anti-E2. The other two patients remained GBV-C/HGV RNA-positive without anti-E2 at the end of follow-up. Sixty-five samples tested were mutually and exclusively positive for either GBV-C/HGV RNA or anti-E2; only one sample was positive for both GBV-C/HGV RNA and anti-E2. In conclusion, the development of anti-E2 of GBV-C/HGV usually indicates the clearance of serum GBV-C/HGV RNA in patients with acute posttransfusion hepatitis.

Acute Disease↗

PubMed1998

Quantitative measurement of serum HCV RNA in patients with chronic hepatitis C: comparison between Amplicor HCV monitor system and branched DNA signal amplification assay.

Quantitative measurement of serum hepatitis C virus (HCV) RNA is important in predicting and monitoring the therapeutic effects of interferon in treating patients with chronic hepatitis C. We compared two commercial available assays, Roche Amplicor HCV Monitor test kits and Chiron branched DNA signal amplification (bDNA) assay, in quantitative measurement of serum HCV RNA in 74 patients with chronic hepatitis C. The serum HCV RNA of each of these patients was qualitatively positive by conventional reverse transcription-nested polymerase chain reaction. Serum HCV RNA was detected positive by the Amplicor test kits in 63 (85%) patients and by the bDNA assay in 58 (78%) patients (P > 0.05). The quantitative results of HCV RNA detected by both assays showed a good linear correlation (r = 0.56, P < 0.001). Amplicor test kits detected 5 patients with low viremia which were below the detection limit of the bDNA assay (2.0 x 10(5) genome equivalents/ml). However, the mean HCV RNA values detected by the Amplicor test kits was 1.26 log lower than that of the bDNA assay. The Amplicor test kits detected only 5 samples (8%) with a HCV RNA value greater than 5 x 10(6) copies/ml, while the bDNA assay detected 23 samples (40%) with a HCV RNA value greater than 5 x 10(6) genome equivalents/ml (P < 0.01). HCV genotype did not affect the positive rate of HCV RNA measurement detected by both assays. However, a significantly higher mean serum HCV RNA value was noted in HCV genotype 1b as compared with the other genotypes. We concluded that the Roche Amplicor HCV Monitor test kits and the Chiron branched DNA signal amplification assay are equally sensitive in the quantitative measurement of serum HCV RNA in patients with chronic hepatitis C and can be reliably used in measuring HCV viremia clinically.

Female↗

PubMed1998

The impact of traveling to endemic areas on the spread of hepatitis E virus infection: epidemiological and molecular analyses.

Traveling to endemic areas carries a risk of hepatitis E virus (HEV) infection, but no molecular analysis to document sources of infection is available. Eighteen (38%) of 47 patients with acute non-A, non-B, non-C hepatitis were positive for antibody to HEV (anti-HEV), and 9 (50%) of these were also positive for serum HEV RNA by polymerase chain reaction following reverse transcription. Only 1 (5%) of the 21 patients with acute hepatitis A was positive for HEV RNA. Travel to endemic areas (mostly to China; odds ratio, 22.2; 95% confidence interval, 4.7-105.8) and deeper jaundice (odds ratio, 5.2; 95% confidence interval, 1.01-27.2) were the only factors associated with HEV infection in multivariate analysis. The two HEV isolates from two patients who had traveled to China and the HEV isolate from a patient whose travel history was obscure formed a monophyletic group with the isolates from Guangzhou. The HEV isolates from our patients show a homology of 72% to 78% in nucleotide sequence with the Burma, Beijing, India, Pakistan, and Xiangjiang strains; a homology of 81% to 91% with the Guangzhou strains; and a homology of 76% with the Mexico strain. The close relationship between the Taiwan isolates and the Guangzhou strains was further supported by the short Kimura's two-parameter distances among them. In summary, HEV infection does occur in this area. Epidemiological and molecular analyses strongly indicate that most cases of HEV infection originated from travel to HEV-endemic areas.

Adult↗

PubMed1998

Co-localization of hypoxia and apoptosis in irradiated and untreated HCT116 human colon carcinoma xenografts.

HCT116 human colon carcinoma xenografts were grown in nude mice. Frozen sections of control and irradiated tumors were stained and analysed for the distribution and extent of hypoxia and apoptosis. Tissue oxygen partial pressure was measured by immunohistochemical staining of hypoxia-dependent metabolites of the 2-nitroimidazole EF5. Apoptosis was assessed using a commercial kit which stains damaged DNA. Although the apoptosis stain was unlikely to exclude other forms of cell death (necrosis, pyknosis) all staining was found to associate with regions of near anoxia.

Animals↗

PubMed1998

Rapid diagnosis of smear-negative pulmonary tuberculosis via fibreoptic bronchoscopy: utility of polymerase chain reaction in bronchial aspirates as an adjunct to transbronchial biopsies.

Fibreoptic bronchoscopy was performed on 190 patients with chest radiographic lesions and negative sputum smears for acid-fast bacilli. Aside from obtaining transbronchial biopsies for histological examination, bronchial aspirate specimens were also tested for Mycobacterium tuberculosis complex DNA by a conventional polymerase chain reaction (PCR) technique. Of 177 transbronchial biopsies performed, a diagnosis was found in 64 cases [43 cases of tuberculosis (TB), 17 cases of lung carcinoma and four cases of other infective/inflammatory diseases] giving a diagnostic yield of 36.2%. PCR was positive in 105 of 108 finally diagnosed cases of TB and 22 of 82 non-TB cases. The sensitivity, specificity, positive predictive value and negative predictive value of PCR when applied to bronchial aspirate specimens for diagnosing smear-negative pulmonary TB were 97.2%, 73.2%, 82.7% and 95.2% respectively. Therefore, detection of M. tuberculosis complex DNA in bronchial aspirates by PCR might have an adjunctive place to transbronchial biopsies in the rapid diagnosis of smear-negative pulmonary tuberculosis.

Adolescent↗

PubMed1998

Cytokine production in varicella-zoster virus-stimulated cultures of human blood lymphocytes.

Estimates of responder cell frequency (RCF) based on limiting dilution analyses are laborious, and alternative means to quantitate cell-mediated immunity to immunogens are desirable. It was shown that levels of interleukin (IL)-2 in the supernatant of varicella-zoster virus-stimulated blood lymphocytes from immune adults peaked at 48 h of culture and correlated partially with estimates of RCF (r = .74, P = .003). Levels of gamma-interferon, IL-4, and IL-10 increased through the first 4 days of culture, and gamma-interferon levels showed some correlation with peak IL-2 levels (r = .48, P = .03). Nevertheless, correlations between levels of these cytokines and RCF did not reach statistically significant levels.

Adult↗

PubMed1998

Cellular immunity to varicella-zoster virus in patients with major depression.

The incidence of herpes zoster increases markedly with advancing age, and this appears to be causally related to an age-dependent decline in varicella-zoster virus (VZV)-specific cellular immunity. Psychologic stress has also been linked to the occurrence of herpes zoster, but the mechanism involved has not been investigated. This study examined the relationship between major depression and VZV-specific cellular immunity by comparing VZV-specific responder cell frequency (RCF) in adults with major depression (n = 11) to that in age- and sex-matched nondepressed controls (n = 11) and in a larger group of nondepressed adults who were > or = 60 years old. VZV-specific RCF in depressed patients was markedly reduced compared with the RCF in matched controls (t = 2.7, P < .02). In fact, the levels of VZV-specific RCF in the depressed patients were comparable in magnitude to the low levels found in adults > or = 60 years of age. These data indicate that major depression is associated with a marked decline in VZV-specific cellular immunity.

Adult↗

PubMed1998

Clinical significance of serum auto-antibodies in Chinese patients with chronic hepatitis C: negative role of serum viral titre and genotype.

Positive serum anti-nuclear antibody (ANA) and anti-smooth muscle antibody (SMA) have been reported in 10-66% of patients with chronic hepatitis C virus (HCV) infection from Western countries. However, the mechanism involved in this immunological disorder is still unknown. This study was carried out to evaluate the prevalence and clinical significance of positive serum auto-antibodies in Chinese patients with chronic hepatitis C and to assess the role of serum HCV-RNA titre and HCV genotype in the presence of serum auto-antibodies. Serum ANA, SMA and anti-mitochondrial antibody (AMA) were measured in 122 patients with chronic hepatitis C. Clinical, biochemical and virological data (serum HCV-RNA titre and HCV genotype) were compared between patients with and without serum auto-antibodies. Fifty-eight (48%) patients were associated with positive serum auto-antibodies: 42 (34%) positive for ANA, six (5%) positive for SMA, nine (7%) positive for both ANA and SMA and one (1%) positive for AMA. Clinical parameters (age, sex, blood transfusion history), liver biochemical tests, the presence of cryoglobulinaemia or cirrhosis, and the response to interferon treatment were not significantly different between patients with and without positive serum auto-antibodies. Serum HCV-RNA levels and HCV genotypes were also not significantly different between the two groups. Logistic regression analysis showed that none of the previously mentioned parameters were significant predictors to associate with serum auto-antibodies in chronic hepatitis C. We concluded that 48% of Chinese patients with chronic hepatitis C were associated with positive serum auto-antibodies. Hepatitis C virus genotypes and serum HCV-RNA levels were not correlated to the presence of serum auto-antibodies. The clinical significance and actual pathogenesis of this phenomenon remain to be clarified.

Antibodies, Antinuclear↗

PubMed1998

Effect of desiccation on the ultrastructural appearances of Acinetobacter baumannii and Acinetobacter lwoffii.

An Acinetobacter baumannii isolate survived desiccation beyond 30 days and an Acinetobacter lwoffii isolate up to 21 days. For both species, desiccation resulted in a significant increase in the proportion of round cells (A baumannii, 40% to 80%; A lwoffii, 51% to 63%) and a significant decrease in rod shaped cells (A baumannii, 58% to 13%; A lwoffii, 46% to 34%). Electronmicroscopic examination showed that there was also a corresponding significant increase in the cell wall thickness (A baumannii, up to 53%; A lwoffii, up to 26%). Desiccated A baumannii cells became more electron-dense and had significantly thicker cell walls (x1.3) than those of A lwoffii. Cell wall structures of A baumannii strains with different abilities to resist desiccation deserve further study.

Acinetobacter↗