Rapid Immunofluorescence Microscopy for Diagnosis of Melioidosis

An immunofluorescent (IF) method that detects Burkholderia pseudomallei in clinical specimens within 10 min was devised. The results of this rapid method and those of an existing IF method were prospectively compared with the culture results for 776 specimens from patients with suspected melioidosis. The sensitivities of both IF tests were 66%, and the specificities were 99.5 and 99.4%, respectively.     

Impact of insulin on survival of cachectic tumor-bearing rats

The present study was performed to determine if a host nutritional treatment, insulin, in the absence of antitumor treatment could improve survival of cachectic tumor-bearing (TB) rats. Initially food intake and host weight were correlated with survival of untreated rats with similar size sarcomas (45-50 cm3). TB rat food intake (r = 0.69, p less than 0.0001) and host weight (r = 0.47, p less than 0.004) correlated positively with subsequent survival. Once daily neutral protamine hagedorn (NPH) insulin treatment (2 units/100 g) significantly improved food intake (p less than 0.01) and host weight (p less than 0.01) of cachectic TB rats without increasing tumor growth. Twice daily NPH insulin (2 units/100 g) maintained normal food intake of cachectic TB rats and turned a host weight loss into a host weight gain which was significantly greater than untreated controls (p less than 0.001) and all other methods of insulin administration including once daily (p less than 0.001). Twice daily NPH insulin maintained mild hypoglycemia (glucose = 84 +/- 12 mg/dl) compared to once daily NPH insulin which resulted in hyperglycemia (glucose = 140 +/- 8 mg/dl, p less than 0.001) prior to next dose. In addition, twice daily NPH insulin did not increase tumor growth. Once daily NPH insulin for 5 days during cachectic decline was well tolerated (no treatment deaths), and improved median survival of TB rats randomized to insulin (15 days) compared to controls (13 days, p = 0.06). However, twice daily NPH insulin during cachectic decline failed to improve survival because of treatment deaths.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evidence for proteolytic cleavage of the 120-kilodalton outer membrane protein of rickettsiae: identification of an avirulent mutant deficient in processing.

The 120-kDa rickettsial outer membrane protein (rOmpB) is encoded by a gene with the capacity to encode a protein of approximately 168 kDa. The carboxy-terminal end of the molecule is apparently cleaved to yield 120- and 32-kDa products. Both polypeptides are surface exposed and remain associated with the outer membrane of intact rickettsiae. All species of rickettsiae examined display similar cleavage of rOmpB. Comparison of diverse species of rickettsiae demonstrate a conserved N terminus of the 32-kDa fragment, with a predicted procaryotic secretory signal peptide immediately upstream of the proposed cleavage site. Coprecipitation of the 120-kDa rOmpB protein and the 32-kDa peptide by monoclonal antibodies specific for the 120-kDa portion of the molecule suggests that the two fragments remain noncovalently associated on the surface of rickettsiae. Analysis of an avirulent mutant of Rickettsia rickettsii revealed reduced amounts of the 120- and 32-kDa fragments, but with a correspondingly larger rOmpB protein that displayed properties expected of the putative precursor. This avirulent mutant grows intracellularly but fails to cause the lysis of infected cells that is typical of R. rickettsii. DNA sequence analysis of the region of the gene encoding the cleavage site of the avirulent strain revealed no difference from the sequence obtained from virulent R. rickettsii. The 168-kDa putative precursor of the avirulent strain of R. rickettsii was not extracted from the surface by dilute buffers, as is the 120-kDa protein of virulent R. rickettsii or R. prowazekii. These latter results suggest that the 32-kDa C-terminal region of the molecule may serve as a membrane anchor domain.     

Differential modulation by dopamine of responses evoked by excitatory amino acids in human cortex.

The responses of human neocortical neurons to iontophoretic application of excitatory amino acids and their modulation by dopamine (DA) were studied in vitro. Brain slices were obtained from children undergoing surgery for intractable epilepsy. Application of N-methyl-D-aspartate (NMDA) to the slices induced slow depolarizations accompanied by decreased input conductances and sustained action potentials in cortical neurons. Glutamate produced rapid depolarizations and firing with few changes in input conductances. Quisqualate also induced depolarization and firing, but input conductances increased during the rising phase of the membrane depolarization. Iontophoretic application of DA alone produced no change in membrane potential or input conductance. However, when DA was applied in conjunction with the excitatory amino acids, it produced contrasting effects. With either bath application of DA or when iontophoresis of DA preceded application of NMDA, the amplitude of the membrane depolarizations and the number of action potentials were increased, whereas the latency of these responses decreased. In contrast, DA decreased the amplitude of the depolarizations and the number of action potentials evoked by glutamate or quisqualate. The fact that DA affects responses to NMDA and glutamate or quisqualate in opposite directions is of considerable importance to the understanding of cellular mechanisms of neuromodulation and the role of DA in cognitive processing and in epilepsy.     

Effect of fibreoptic bronchoscopy on pulmonary function.

Several studies have shown that after fibreoptic bronchoscopy there may be a deterioration in lung function but it is not known whether this is due to the premedication, the topical anaesthetic, or the obstruction produced by the bronchoscope. The effects of each part of the procedure on spirometric measurements were studied in patients with lung disease and in normal non-smokers. Measurements were made after premedication (papaveretum and atropine) in seven patients and after topical anaesthesia of the bronchial tree (340 mg lignocaine) with and without the bronchoscope in the trachea in 21 patients and 10 control subjects. Premedication had no effect. In the normal subjects lignocaine produced significant falls in FEV1, forced vital capacity (FVC), peak expiratory flow (PEF), and peak inspiratory flow (PIF), and insertion of the bronchoscope caused further falls that were also significant. In the patients, however, although anaesthesia produced significant falls in FEV1, FVC, PEF, and PIF of similar magnitude to those found in the normal subjects, there was no further important decrease when the bronchoscope was inserted. It is concluded that the major effect of bronchoscopy on lung function is due to topical lignocaine in the airways, and in patients with lung disease (excluding asthma or a central obstructing carcinoma) the insertion of the bronchoscope causes little additional obstruction.     

Methicillin-resistant Staphylococcus aureus: investigation of a hospital outbreak using a case-control study

A retrospective case-control study of 50 MRSA-positive patients was carried out during an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) at an acute general hospital in London. Controls were randomly selected from MRSA-negative patients admitted during the outbreak period. Risk factors investigated included length of admission prior to screening, number of ward changes, main diagnosis, extent of staff contact, pressure sores, surgical and other invasive procedures and antibiotic treatment. Outcome variables examined were rates of infection (versus colonization) with MRSA and mortality. Patients with MRSA were in hospital longer before microbiological specimens were taken and moved wards more often than controls. In a logistic regression analysis, length of stay in hospital, pressure sores, physiotherapy and surgical procedures were associated with a significantly increased risk of acquiring MRSA. Odds ratios (and 95% confidence intervals) for having acquired MRSA were: 8·3 (1·02−71·43) if a patient had pressure sores; 3·7 (1·10−12·5) if they received physiotherapy; and 3·2 (1·82−10·0) if they underwent surgical procedures. The rate of clinical infection amongst patients with this strain of MRSA was 26% and included life-threatening infections such as septicaemia, underlining the potential virulence of MRSA. Surgery and physiotherapy may have been markers of debility. Physiotherapy was probably a marker of increased rates of contact with all hospital staff, and high standards of hand hygiene should be promoted amongst all staff as the most important factor in controlling an outbreak of MRSA. Good bed management is essential for hospital infection control.     

Effects on birthweight of alcohol and caffeine consumption in smoking women.

STUDY OBJECTIVE--Previous work found no effect on birthweight of alcohol and caffeine consumption in non-smokers but such an effect was found in smokers. This report investigates further the effects on birthweight of alcohol and caffeine at three stages of pregnancy in smoking women. DESIGN--This was a prospective population study. SETTING--District general hospital in inner London. PARTICIPANTS--Out of 1309 women who completed all pregnancy interviews, 895 were excluded because they did not smoke, leaving a sample of 414 smokers. MEASUREMENTS AND MAIN RESULTS--Number and brand of cigarettes smoked, and quantity of alcohol and caffeine consumed were obtained by interview at booking, 28, and 36 weeks gestation. Birthweight was corrected for gestation and adjusted for maternal height, sex of infant and parity. The effect on birthweight of alcohol consumption was not explained by the amount smoked in terms of quantity and yield. Similarly the effect of caffeine was independent of smoking. When alcohol, caffeine, and smoking were analysed together, alcohol and caffeine were both associated with reductions in birthweight. Alcohol was associated with a reduction of up to 8% after adjusting for tobacco and caffeine intake, and caffeine was associated with a reduction of up to 6.5% after adjusting for tobacco and alcohol intake. Women who at booking were heavy smokers (greater than or equal to 13 cigarettes/day or greater than or equal to 15 mg carbon monoxide/cigarette), heavy drinkers (greater than or equal to 100 g/week alcohol), and had high caffeine intake (greater than or equal to 2801 mg/week) had a predicted reduction in mean birthweight of 18% (95% CI 11% to 24%). CONCLUSIONS--It is well known that women who smoke in pregnancy have smaller babies than non-smokers. Our study suggests that if these women also drink alcohol and high quantities of caffeine then the risk of poor fetal growth is increased even further.