Alternative complement pathway activation by Salmonella O polysaccharide as a virulence determinant in the mouse

The quality of Salmonella O polysaccharide (the O antigen) is a virulence factor in mouse salmonellosis. It affects the rate by which these bacteria are phagocytosed and by which they activate the alternative complement pathway in a manner inversely proportional to their virulence, suggesting that the rate of complement activation is crucial for the fate of the bacteria in the mouse. The effector mechanism has, however, remained open since Salmonellae survive and multiply in the macrophages of the mouse. We show in this study that although the least virulent O-6,7 Salmonellae multiply in the liver macrophages they are rapidly killed in the peritoneal cavity by the local resident macrophages. Electron microscopy showed a striking morphological feature--a 35 nm thick homogenous electron-dense deposit--on all the bacteria found in association with the macrophages but absent from all non-cell-associated bacteria. A similar precipitate was formed by incubating the bacteria in fresh mouse serum and was dependent on heat-labile serum components and bound anti-C3. The least virulent O-6,7 bacteria acquired this deposit more rapidly and in a lower concentration of serum than the more virulent O-4,12 bacteria consistent with the previously demonstrated difference between these bacteria in their rate of complement activation via the alternative pathway. Preincubation of the O-4,12 bacteria in fresh mouse serum leading to complement deposition on 80% of the bacteria effectively opsonized them for rapid killing in the peritoneal cavity. These data for the first time demonstrate how the rate of complement activation determines the virulence of Salmonellae.     

Cognitive impairment. Can it predict the course of hospitalized patients?

All patients admitted to three medical services at the New York Hospital during a one-month period were screened with Folstein's Mini-Mental State Examination. The prevalence of cognitive impairment was 19.8% (23 of 116). Cognitively "impaired" patients, ie, those with a Folstein score less than 24, were older, sicker, and less physiologically stable than the cognitively "intact." The in-hospital mortality (17 versus 5%) and morbidity (39 versus 18%) rates were higher for the cognitively "impaired" patients; these differences could be explained by the greater severity of illness, instability, and comorbidity found in these patients. Cognitively "impaired" patients were particularly susceptible to respiratory complications. Cognitively "impaired" patients had longer lengths of hospital stay, spent more time in hospital awaiting placement, and were more likely to be discharged to a nursing home or require home assistance than their cognitively "intact" counterparts. Three-month mortality rates were also higher for the cognitively "impaired" patients (30 versus 15%). These findings suggest that cognitive impairment on admission may be regarded as a marker for patients with poorer prognoses.     

Magnetic resonance imaging of thoracic aortic dissections

Magnetic resonance imaging is an excellent noninvasive method for evaluating thoracic aortic dissections. A variety of magnetic resonance scans of aortic dissections are shown, documenting the ability of magnetic resonance to image the true lumen, the false channel, and the intimal septum. Detail is provided on magnetic resonance imaging techniques and findings.     

A patient's guide to protease inhibitors

Dosage guidelines and side effects of three currently available protease inhibitors (saquinavir, ritonavir, indinavir) reveal very different patterns. Dosage regimens are as follows: saquinavir, 3 capsules every 8 hours with food; ritonavir, 6 capsules every 12 hours with food; and indinavir, 2 capsules every 8 hours on an empty stomach. Ritonavir has the severest side effects, including nausea, diarrhea, and initially, tingling feeling of the mouth, arms, or legs. The drugs work best when taken with well-studied medicines such as AZT, d4T, and ddI.     

Clinical pharmacists as allied health care providers to psychiatric patients

The effect of clinical pharmacy services on the quality and economy of health care provided to psychiatric patients at a Veterans Administration outpatient clinic was evaluated. Twenty-one patients were selected from the Day Treatment Center, of these, 19 patients completed the study. In providing health care to these psychiatric patients, the clinical pharmacist used a systemized approach including data gathering, evaluation, plan of action, and follow-up. In addition, medication groups and weekly staff meetings were incorporated into the patient treatment plan. Following a 3-month study period, the impact of clinical pharmacy services was evaluated. The provision of allied health care to psychiatric patients by clinical pharmacists resulted in a decreased incidence and severity of adverse drug effects, fewer drug use problems, a reduction in the total number of drugs prescribed, improved patient drug knowledge, and reduced expenditures for health care without compromising the patient's mental functioning.     

Fatal meningoencephalitis due to Bacillus anthracis

Abstract: We report the first case of fatal anthrax meningoencephalitis in Hong Kong over the past 60 years. A 13 year-old boy presented with right lower quadrant pain, diarrhoea and progressive headache. Lumbar puncture yielded gram positive bacilli initially thought to be Bacillus cereus, a contaminant. He was treated with ampicillin and cefotaxime, but died 3 days after hospitalization. The organism isolated from blood and cerebrospinal fluid was later identified as Bacillus anthracis.     

Prevalence of nosocomial infections in Swiss children's hospitals.

OBJECTIVE: To acquire data on pediatric nosocomial infections (NIs), which are associated with substantial morbidity and mortality and for which data are scarce. DESIGN: Prevalence survey and evaluation of a new comorbidity index. SETTING: Seven Swiss pediatric hospitals. PATIENTS: Those hospitalized for at least 24 hours in a medical, surgical, intensive care, or intermediate care ward. RESULTS: Thirty-five NIs were observed among 520 patients (6.7%; range per hospital, 1.4% to 11.8%). Bacteremia was most frequent (2.5 per 100 patients), followed by urinary tract infection (1.3 per 100 patients) and surgical-site infection (1.1 per 100 patients; 3.2 per 100 patients undergoing surgery). The median duration until the onset of infection was 19 days. Independent risk factors for NI were age between 1 and 12 months, a comorbidity score of 2 or greater, and a urinary catheter. Among surgical patients, an American Society of Anesthesiologists (ASA) score of 2 or greater was associated with any type of NI (P = .03). Enterobacteriaceae were the most frequent cause of NI, followed by coagulase-negative staphylococci; viruses were rarely the cause. CONCLUSIONS: This national prevalence survey yielded valuable information about the rate and risk factors of pediatric NI. A new comorbidity score showed promising performance. ASA score may be a predictor of NI. The season in which a prevalence survey is conducted must be considered, as this determines whether seasonal viral infections are observed. Periodic prevalence surveys are a simple and cost-effective method for assessing NI and comparing rates among pediatric hospitals.