Contacts of healthcare workers, patients and visitors in general wards in Singapore.

To characterize contacts in general wards, a prospective survey of healthcare workers (HCWs), patients and visitors was conducted using self-reported diary, direct observation and telephone interviews. Nurses, doctors and assorted HCWs reported a median of 14, 18 and 15 contact persons over one work shift, respectively. Within 1 h, we observed 3·5 episodes with 25·6 min of cumulative contact time for nurses, 2·9 episodes and 22·1 min for doctors and 5·0 episodes with 44·3 min for assorted-HCWs. In interactions with patients, nurses had multiple brief episodes of contact; doctors had fewer episodes and less cumulative contact time; assorted-HCWs had fewer contact episodes of longer durations (than for nurses and doctors). Assortative mixing occurred amongst HCWs: those of the same HCW type were the next most frequent class of contact after patients. Over 24-h, patients contacted 14 persons with 23 episodes and 314·5 min of contact time. Patient-to-patient contact episodes were rare, but a maximum of five were documented from one patient participant. 22·9% of visitors reported contact with patients other than the one they visited. Our study revealed differences in the characteristics of contacts among different HCW types and potential transmission routes from patients to others within the ward environment.

Comparing the effects of meal replacements with reduced-fat diet on weight, sexual and endothelial function, testosterone and quality of life in obese Asian men.

Sexual dysfunction is more prevalent in obese than in normal-weight men. Meal replacements (MRs) are useful weight-loss strategies. We randomized obese (body mass index 27.5 kg m(-2), waist circumference (WC) 90 cm) Asian men (mean age 40.5 years, range 30-61) to a conventional reduced-fat diet (CD) (n=24) or MR-based plan (n=24) to reduce daily intake by 400 kcal for 12 weeks. There were significantly greater reductions in weight (4.2 ± 0.8 kg), WC (4.6 ± 0.7 cm), calorie and fat intake in the MR group, compared with the CD group (2.5 ± 0.4 kg, 2.6 ± 0.5 cm). Erectile function (International Index of Erectile Function 5-item score) improved comparably in the MR (3.4 ± 0.7 points) and CD (2.5 ± 0.5 points) groups, as did the Sexual Desire Inventory score (5.5 ± 2.3 vs 7.7 ± 2.1 points), quality of life (36-item Short Form survey score), plasma testosterone and endothelial function (Reactive Hyperemia Index). Subjects were switched to or continued CD for another 28 weeks. Weight, WC and erectile function were maintained at 40 weeks. MR induces greater reductions in weight and abdominal obesity than conventional diet, and comparable improvements in sexual and endothelial function, testosterone and quality of life.

Lack of association between RANTES-28, SDF-1 gene polymorphisms and systemic lupus erythematosus in the Malaysian population.

Regulated on activation, normal T-cell expressed and secreted (RANTES) and stromal cell-derived factor 1 (SDF-1) are members of the CC- and CXC-chemokine families, respectively. Both genes have been postulated to be involved in the pathogenesis of systemic lupus erythematosus (SLE). We analyzed position 28 of the RANTES gene promoter region, as well as the SNP observed in the 3' UTR of the SDF-1 gene at position 801, in 130 patients presenting SLE at the Malaya University Medical Centre. Screening of 130 healthy volunteer controls using RFLP was also performed. RANTES-28 polymorphism analysis showed no significant (P = 0.3520) relationship, even though homozygous C/C was more frequent in SLE patients (OR = 1.4183) and heterozygous C/G was more frequent in healthy controls (OR = 0.7051). There were no significant (P = 0.2650) associations between A/A (OR = 0.783), G/G (OR = 1.5914) and G/A (OR = 0.8289) genotypes in the SDF-1 gene polymorphism with SLE. We conclude that there is no significant association of RANTES-28 and SDF-1 gene polymorphisms and occurrence of SLE in Malaysia.

Aberrantly high glycated haemoglobin measurement due to the haemoglobin variant Hb Santa Juana.

Various laboratory and patient-related factors can result in falsely high or low glycated haemoglobin (HbA1c) measurements, and haemoglobin (Hb) variants that interfere with laboratory readings is an important cause of this. We report a case of a rare Hb variant, Hb Santa Juana, manifesting as a falsely high HbA1c in a 62-year-old patient with type 2 diabetes mellitus. The patient presented with high HbA1c values that persisted despite the intensification of anti-diabetic treatment. His home blood glucose levels were incongruently low compared to his HbA1c values. Further investigations revealed a family history of the variant Hb Santa Juana. This was confirmed in the patient when his blood was sent for DNA analysis. It is important for clinicians to be aware of the factors that can influence laboratory HbA1c measurements, as clinical decisions on treatment are often based on these measurements.

Acute epiglottitis in adults: a retrospective review of 106 patients in Hong Kong.

OBJECTIVES: Acute epiglottitis in adult is a potentially life-threatening condition that may be underdiagnosed. The present study reports the clinical features, management and patient outcomes in an acute hospital in Hong Kong over a seven-year period. METHOD: All adult patients aged 18 years or above admitted to Tuen Mun Hospital between July 1999 and June 2006 with the diagnosis of acute epiglottitis were included in this retrospective study. The diagnosis of acute epiglottitis was established by direct visualisation of inflamed epiglottis during laryngoscopic examination. RESULTS: 106 patients were identified. A total of 21 patients (20%) had co-morbidities, with diabetes mellitus (11%) being the most common. Five patients had a history of nasopharyngeal carcinoma and three patients had a previous history of acute epiglottitis. The majority (94%) of patients presented with sore throat as their major complaint. Blood cultures were collected from 15 patients and all were negative. A combination of cefotaxime and metronidazole was the most common empirical antibiotic regimen prescribed. Seven patients required active airway intervention (six with endotracheal intubation and one failed intubation with emergency tracheostomy performed). No mortality was reported. CONCLUSION: Acute epiglottitis in adults is not a rare entity and vigilance for this condition is needed. In general, the prognosis is good with antimicrobial therapy, close monitoring and selective airway intervention.

Murine cytomegalovirus resistant to antivirals has genetic correlates with human cytomegalovirus.

Human cytomegalovirus (HCMV) resistance to antivirals is a significant clinical problem. Murine cytomegalovirus (MCMV) infection of mice is a well-described animal model for in vivo studies of CMV pathogenesis, although the mechanisms of MCMV antiviral susceptibility need elucidation. Mutants resistant to nucleoside analogues aciclovir, adefovir, cidofovir, ganciclovir, penciclovir and valaciclovir, and the pyrophosphate analogue foscarnet were generated by in vitro passage of MCMV (Smith) in increasing concentrations of antiviral. All MCMV antiviral resistant mutants contained DNA polymerase mutations identical or similar to HCMV DNA polymerase mutations known to confer antiviral resistance. Mapping of the mutations onto an MCMV DNA polymerase three-dimensional model generated using the Thermococcus gorgonarius Tgo polymerase crystal structure showed that the DNA polymerase mutations potentially confer resistance through changes in regions surrounding a catalytic aspartate triad. The ganciclovir-, penciclovir- and valaciclovir-resistant isolates also contained mutations within MCMV M97 identical or similar to recognized GCV-resistant mutations of HCMV UL97 protein kinase, and demonstrated cross-resistance to antivirals of the same class. This strongly suggests that MCMV M97 has a similar role to HCMV UL97 in the phosphorylation of nucleoside analogue antivirals. All MCMV mutants demonstrated replication-impaired phenotypes, with the lowest titre and plaque size observed for isolates containing mutations in both DNA polymerase and M97. These findings indicate DNA polymerase and protein kinase regions of potential importance for antiviral susceptibility and replication. The similarities between MCMV and HCMV mutations that arise under antiviral selective pressure increase the utility of MCMV as a model for in vivo studies of CMV antiviral resistance.

Treatment of vancomycin-intermediate Staphylcoccus aureus endocarditis with linezolid.

We report a case of infective endocarditis due to vancomycin-intermediate Staphylococcus aureus that developed after repeated courses of vancomycin. The patient had underlying end stage renal disease and dissecting aortic aneurysm with aortic graft and prosthetic aortic valve replacement. He responded to prolonged combination therapy with linezolid and amikacin without undergoing surgical intervention.

The first patient with locally acquired dengue fever in Hong Kong.

This report is of the first locally acquired case of dengue fever. The diagnosis was made even in the absence of a history of travel outside Hong Kong. The patient was a 21-year-old man, who presented with high fever, leukopenia, thrombocytopenia, and elevated liver enzymes. His haematocrit revealed mild haemoconcentration but the albumin was normal throughout the course of the illness. His blood pressure remained low with no tachycardia or overt shock syndrome. The pyrexia subsided 4 days after admission to hospital and all haematological and biochemical abnormalities eventually normalised. The pathogenesis, diagnostic criteria of dengue haemorrhagic fever and dengue shock syndrome, and control of dengue infection are discussed.

The rotary pursuit test is not an index of normal psychomotor function in humans.

OBJECTIVE: This study sought to assess whether the rotary pursuit test is a good indication of the psychomotor performance of human subjects during normal working hours. Circadian hormonal profiles of salivary melatonin and cortisol were also established for correlation with performance. METHODS: Ten healthy individuals working in the Department of Obstetrics and Gynecology laboratory participated in this study. The experiment was conducted during a normal 8.5-hour working day in which routine laboratory tasks such as running radioimmunoassays were performed. Saliva samples were collected every 2 hours starting at 8:00 a.m. Simultaneously, self-rated questionnaires on mood states, sleepiness, stress, and types of food and drinks consumed were also recorded. At 10:00 a.m., 12:00 noon, 2:00 p.m., and 4:00 p.m., the subjects' were tested on the rotary pursuit machine, on which their ability to track a rotating target with a stylus was tested by means of measuring the time the stylus stays on target. RESULTS: The circadian profiles of salivary melatonin and cortisol were similar to what previous studies have shown. Increases in cortisol levels were associated with food intake, work stress, or spontaneous awakening. Tracking performance (time on target) improved significantly from 10:00 a.m. to 2:00 p.m. and then decreased nonsignificantly at 4:00 p.m. only at the speed setting of 60 rpm. There was no correlation between the three parameters measured. SUMMARY: Variation of psychomotor performance during a normal working day and in noncircadian disrupted individuals cannot be measured by the rotary pursuit test. Furthermore, a learning effect could mask any variation in performance.

The structure of a stable intermediate in the A <--> B DNA helix transition.

The DNA dodecamer CATGGGCCCATG in a crystal structure of resolution 1.3 A has a conformation intermediate between A and B DNA. This trapping of a stable intermediate suggests that the A and B DNA families are not discrete, as previously believed. The structure supports a base-centered rather than a backbone-centered mechanism for the A <--> B transition mediated by guanine tracts. Interconversion between A and B DNA provides another means for regulating protein-DNA recognition.

Local conformational variations observed in B-DNA crystals do not improve base stacking: computational analysis of base stacking in a d(CATGGGCCCATG)(2) B<-->A intermediate crystal structure.

The crystal structure of d(CATGGGCCCATG)(2) shows unique stacking patterns of a stable B<-->A-DNA intermediate. We evaluated intrinsic base stacking energies in this crystal structure using an ab initio quantum mechanical method. We found that all crystal base pair steps have stacking energies close to their values in the standard and crystal B-DNA geometries. Thus, naturally occurring stacking geometries were essentially isoenergetic while individual base pair steps differed substantially in the balance of intra-strand and inter-strand stacking terms. Also, relative dispersion, electrostatic and polarization contributions to the stability of different base pair steps were very sensitive to base composition and sequence context. A large stacking flexibility is most apparent for the CpA step, while the GpG step is characterized by weak intra-strand stacking. Hydration effects were estimated using the Langevin dipoles solvation model. These calculations showed that an aqueous environment efficiently compensates for electrostatic stacking contributions. Finally, we have carried out explicit solvent molecular dynamics simulation of the d(CATGGGCCCATG)(2) duplex in water. Here the DNA conformation did not retain the initial crystal geometry, but moved from the B<-->A intermediate towards the B-DNA structure. The base stacking energy improved in the course of this simulation. Our findings indicate that intrinsic base stacking interactions are not sufficient to stabilize the local conformational variations in crystals.

Detecting protein function and protein-protein interactions from genome sequences.

A computational method is proposed for inferring protein interactions from genome sequences on the basis of the observation that some pairs of interacting proteins have homologs in another organism fused into a single protein chain. Searching sequences from many genomes revealed 6809 such putative protein-protein interactions in Escherichia coli and 45,502 in yeast. Many members of these pairs were confirmed as functionally related; computational filtering further enriches for interactions. Some proteins have links to several other proteins; these coupled links appear to represent functional interactions such as complexes or pathways. Experimentally confirmed interacting pairs are documented in a Database of Interacting Proteins.

Structure of a dicationic monoimidazole lexitropsin bound to DNA.

An X-ray crystal structure has been solved of the complex of a dicationic lexitropsin with a B-DNA duplex of sequence CGCGAATTCGCG. The lexitropsin is identical to netropsin except for replacement of the first methylpyrrole ring by methylimidazole, converting a =CH- to =N-. Crystals are isomorphous with those of the DNA dodecamer in the absence of drug. Although the =N- for =CH- substitution was intended to make that locus on the drug molecule compatible with a G.C base pair, electrostatic attraction for the two cationic ends of the drug predominates, and this lexitropsin binds to the same central AATT site as does the parent netropsin. But unlike netropsin, this lexitropsin exhibits end-for-end disorder in the crystal. Both orientations were refined separately to completion. Final residual errors at 2.25 A resolution for the 2358 reflections above 2 sigma in F are R = 0.165 for one orientation (LexA) with 37 water molecules and 0.164 for the inverted drug orientation (LexB) with 40 water molecules. This molecular disorder is probably attributable to a weakening of binding to the AATT site occasioned by the imidazole-for-pyrrole substitution.

Selective decrease of the suppressor-inducer (CD4+CD45RA+) T lymphocytes in workers exposed to benzidine and beta-naphthylamine.

Previously, we reported a decrease of CD4+ T lymphocytes in workers exposed to benzidine and beta-naphthylamine, which are aromatic amines. In the present study, CD4+ T lymphocyte subpopulations (i.e., CD4+CD45RA+ and CD4+CD29+ cells), total CD4+ T lymphocytes, and CD8+ T lymphocytes were measured in 78 male dyestuff workers who had been exposed to aromatic amines. The aromatic amine workers consisted of 40 individuals who had engaged in production of aromatic amines (high-exposure group) and 38 workers who had handled only dyestuff in their job (low-exposure group). The control group consisted of 30 healthy male volunteers who were working at the same factory and who did not have a history of occupational exposure to aromatic amines or to other hazardous chemicals. The absolute and relative numbers of CD4+CD45RA+ (suppressor-inducer) T lymphocytes in the high-exposure group of aromatic amine workers were significantly lower than those in the control group, after controlling for the effects of age by the analysis of covariance. Similarly, the relative, but not absolute, number of total CD4+ T lymphocytes in the high-exposure group of aromatic amine workers was significantly lower than that found in the control group. It is suggested that the CD4+CD45RA+ T lymphocyte is a major site of the effects of aromatic amines on lymphocyte subpopulations.

Inhibitors of protein and RNA synthesis block the cytotoxic effects of non-steroidal antiestrogens.

Non-steroidal antiestrogens such as tamoxifen are known to exert cytotoxic effects against various cell lines in culture. When the antiestrogens are present at sufficiently high concentrations, their cytotoxicity cannot be reversed by estrogens and is demonstrable even with cell lines which lack the estrogen receptor. The mechanism of this cytotoxicity, which is clearly independent of estrogen antagonism, remains unknown. Using two murine cancer cell lines (the K36 leukemia and the EL4 lymphoma cell line), the human breast cancer cell line MCF7, and two non-steroidal antiestrogens (tamoxifen and clomiphene), our laboratory attempted to determine whether the cytotoxic action of non-steroidal antiestrogens was mediated by a mechanism requiring protein or RNA synthesis. In the case of K36 and EL4 cells, inclusion of tamoxifen or clomiphene in the culture medium regularly caused the viable call count to fall below 20-30% of control in 36-48 h. Under these conditions, the addition of inhibitors of protein or RNA synthesis consistently increased viable cell count in a dose-dependent manner. With cultures of K36 cells grown in the presence of 10 microM tamoxifen, for example, the addition of appropriate concentrations of emetine, cycloheximide, puromycin, or actinomycin D increased the percentage of viable cells to 5.0, 2.4, 4.0, and 4.0 times that of control, respectively. Additional experiments revealed that the macromolecular synthesis inhibitors, while effective in inhibiting protein or RNA synthesis to varying degrees, did not affect the cellular uptake of [3H]tamoxifen, suggesting that their ability to protect cells against antiestrogen-induced cell death was not due to an inhibition of cellular uptake of antiestrogens. In the case of MCF7 cells, however, inhibition of protein synthesis did not protect the cells against the cytotoxic effect of tamoxifen. These observations suggest that non-steroidal antiestrogens may exert their cytotoxic effect by at least two different mechanisms; only one of these require de novo protein synthesis. The effect of antiestrogens on K36 and EL4 cells may provide a useful system for the identification of proteins involved in cell death.