Molecular pathogenesis of bacterial infections

Somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded in 3 patients with a brain-stem or medullary lesion documented by clinical and CT or MRI evidence. The positive P14 and negative N18 scalp far-fields were preserved. The results suggest that P14 reflects the spike volley in caudal medial lemniscus, and that the N18 neural generators are located in the medulla, probably in the dorsal column nuclei and/or the accessory inferior olives.     

DNA vaccines for bacterial infections

The uptake and transportation of purine and pyrimidine based nucleosides by trophozoites of axenically grown Entamoeba histolytica (HMI-IMSS) were studied. The trophozoites transported adenosine and its analog tubercidin (1 microM) at a significant rate but poor transportation was observed in case of uridine (about 10% relative rate), inosine (3%), thymidine (2%) and formycin B (1%). The Km for adenosine was 160 +/- 42 microM. Unlabeled nucleosides (100 microM) inhibited adenosine and tubercidin transport. Adenosine related compounds 5'-deoxyadenosine and nebularin inhibited adenosine and tubercidine transport by 50% or more. However, inosine related compounds guanosine, 3'-deoxyinosine and formycin B were less inhibitory. The pyrimidine nucleosides uridine, thymidine and cytidine were poorly inhibitory. 6-[(4 nitrobenzyl)-mercapto] purine ribonucleoside, an inhibitor of mammalian nucleoside transporter, inhibited adenosine or tubercidin transport in E. histolytica variably between 0-30% at 10 microM, but dilazep, a known inhibitor, was inactive upto 10 microM. Increase in temperature from 22 degrees C to 33 degrees C enhanced the rate of transport of adenosine 4.5 fold, tubercidin 7.3 fold and of inosine 4 fold. These findings along with the structure activity figures suggested that transport was mediated and not passive.     

Neurologic manifestations of HIV infections and AIDS

The paper presents the review of neurological manifestations of HIV infection. The pathogenesis of changes caused by HIV within central nervous system is discussed. The most common neurological syndromes occurring in AIDS patients as well as the division of these changes concerning peripheral and central nervous system are described.     

Serodiagnosis of atypical bacterial respiratory infections

Since prevalence of antibodies to bacteria causing atypical respiratory infections in Israel is as yet unknown, a 5-year antibody prevalence study was performed. Seroreactivity to Chlamydia pneumoniae (TWAR), with titers > or = 1:16 by microimmunofluorescence assay (MIF) was detected in 725/1305 (55.5%) of patients. 47/1012 ((4.6%) of adult patients had MIF results indicating recent infection with TWAR, (IgG titers of > or = 1:512, and/or IgM titers of > or = 1:16, and/or seroconversion). Antibody prevalence and titers were low in children aged 1-10 years, increased in teenagers, and peaked in adults and the elderly, in whom prevalence was up to 79% and mean geometric titer up to 1:163. Unlike the consistency in TWAR antibody prevalence and serological evidence of recent infection during the study period, a significant decrease in those variables was observed for Chlamydia trachomatis during the first 3 study years. Antibodies to M. pneumoniae were detected in 53 and to Legionella sp. in 47 out of 763 patients. There was serological evidence of recent infection with M. pneumoniae in 10 (including 7 children) and with Legionellae in 8. Improved diagnosis of atypical respiratory infection might be achieved by the combined use of these proposed serological procedures.     

HIV disease and women

Women with HIV disease are at risk for the same complications as men as their disease progresses. Women, however require some special considerations. This article will elucidate the epidemiology, disease transmission, gynecologic complications, pregnancy, and evaluation of the HIV infected women.     

Pulmonary infections in HIV infected patients

We retrospectively reviewed causes, clinical presentations and chest radiographs of pulmonary infections in symptomatic HIV infected patients diagnosed in Srinagarind Hospital from February 1992 to 1994. We found 95 episodes of pulmonary infections in 88 HIV infected patients enrolled in our review. The three most common pathogens were Mycobacterium tuberculosis (37.2%), Pneumocystis carinii (23.8%), and Cryptococcus (15.2%). Coexistent pulmonary infections were seen in 10.5 per cent, mostly due to P. carinii and Cryptococcus neoformans. Extrapulmonary infections were also common, particularly with M. tuberculosis (49%) and C. neoformans (100%). The common clinical presentations were fever, dyspnea, and cough which frequency varied among the organisms. Chest radiographs were nonspecific, the most common finding was bilateral pulmonary infiltrates except that bacterial pneumonia usually presented with unilateral infiltrates. All patients wit PC had significant hypoxia (PaO2 < 70 mmHg). Due to nonspecific clinical and chest film presentations as well as frequent coinfections, definite diagnosis should be carried out in all HIV infected patients with pulmonary infections.     

Respiratory infections in patients with HIV

Pneumocystis carinii pneumonia has long been considered the predominant pulmonary disease in patients with HIV, but several factors are changing this perception. The population infected with HIV is increasingly composed of injection drug users, and racial and ethnic minorities, which represent groups that have a high incidence of bacterial pneumonia and tuberculosis. The increased longevity attributed to antiretroviral therapy and P. carinii pneumonia prophylaxis is accompanied by more profound immunosuppression, rendering patients susceptible to Pseudomonas, Aspergillus, and other opportunistic pneumonias. Trimetrexate and atovaquone are now available for the treatment of P. carinii pneumonia. Both are less effective than standard regimens of trimethoprim-sulfamethoxazole, but have fewer adverse effects. The diagnosis of respiratory infections complicating HIV usually depends on isolation of the pathogen. The routine use of transbronchial biopsy during bronchoscopy is controversial because the prevalence of P. carinii pneumonia is high in most centers caring for patients with AIDS, and bronchoalveolar lavage is usually diagnostic in this disease. However, biopsy enhances the yield of bronchoscopy, especially in the diagnosis of noninfectious pulmonary disorders and infections other than P. carinii pneumonia.     

Common bacterial urinary tract infections in women

Unfortunately, there is no general consensus as to how long patients with bacteriuria or urinary tract infections should be monitored and certainly there is no agreement on how long recurrent episodes should be treated beyond ten days to two weeks. The most important points to remember are: 1. Culture the urine both at the time of therapy and during follow-up. The patient should be examined periodically for the presence of bacteruria. If bacteria cannot be eradicated, at least the physician is aware of the organism most likely causing the patient's symptoms. 2. Do not subject the patient with frequent recurrent (chronic) and complicated infections to continual antibacterial therapy, but rather, manage the acute episodes. 3. Use prophylaxis, particularly single bed-time doses for dysuria and frequency symptoms. 4. Screen for bacteriuria during pregnancy. 5. Avoid the use of catheters except where absolutely necessary. 6. Avoid systemic prophylaxis of infection in patients with catheters; rather, use closed-system drainage with antibacteri-irrigation. It is to be hoped within the next few years, studies now underway will allow specific recommendations regarding the management of asymptomatic bacteruria, the duration of therapy for recurrent infections, the prevention and treatment of L-form bacterial infections, and indications for urologic procedures.     

Acute bacterial meningitis: vascular complications

The authors present the study of four children with arteritis as vascular complication of acute bacterial meningitis. They report pathophysiological mechanisms involved in vascular lesions, and progress in the understanding of these complications.