Binding of pertussis toxin to lipid vesicles containing glycolipids

The binding of pertussis toxin and its B oligomer to lipid vesicles containing glycosphingolipids was studied. Both pertussis toxin and the B oligomer bound to lipid vesicles containing ganglioside GD1a. Binding of pertussis toxin to these vesicles decreased upon treatment of the vesicles with neuraminidase, suggesting that sialic acid residues are important for efficient binding of the toxin to GD1a.     

Trichloroethylene biodegradation by phenoloxidizing cultures grown from various conditions

The rate and extent of trichloroethylene (TCE) degradation by three cultures of phenol oxidizing bacteria grown from two chemostats and one from rotating biological contactors was investigated. Batch experiments were performed to measure the disappearance of TCE both with the resting cell alone and with the formate added. Experimental data were then compared with mathematical predictions from a model describing TCE transformation. Through nonlinear regression analysis, a best fit between the measurements and predictions was achieved when residual sum of squares reached a minimum. Based on the resultant parameters of transformation capacity and reaction rate, the suspended cells with a mean cell retention time (MCRT) of 3.8 days were the most active in degrading TCE, while the attached bacteria had the least activity. Based on the results presented herein, it is recommend that using suspended-growth reactors operated at short MCRT to produce desirable cells for cometablic transformation of TCE.     

Lidocaine block of LQT-3 mutant human Na+ channels

In transiently transfected mammalian cells we have identified pharmacological consequences of a naturally occurring deletion mutation, delta KPQ, of the human heart Na+ channel alpha subunit that previously has been linked to one form of the long QT syndrome, an inherited heart disease. Our results show that the Class IB antiarrhythmic agent lidocaine blocks maintained inward current through and slows recovery from inactivation of delta KPQ-encoded Na+ channels. Block is greater for maintained than for peak current. Because incomplete inactivation of mutant Na+ channels is now thought to underlie the prolonged ventricular action potential, which is the phenotype of this disease, and we find that the delta KPQ mutation speeds the recovery from inactivation of drug-free mutant channels, our results provide evidence, for the first time, that clinically relevant dysfunctional properties of an ion channel can be selectively targeted on the basis of the molecular properties conferred on the channel by an inherited genetic disorder.     

Apoptosis induced by sulindac sulfide in epithelial and mesenchymal cells from human abdominal neoplasms

A tadpole of bullfrog, Rana catesbeiana, is originally covered with the larval skin over its entire body. Drastic changes arise in both the epidermis and the subcutaneous connective tissue at an early developmental stage, producing the precursor of adult type skin (pre-adult skin). It was found that calcium is a useful probe to detect the region where the precursor formation has occurred because its deposition in the upper part of subcutaneous collagen bundles coincides with the appearance of the pre-adult skin. Whole-mount in situ staining of tadpoles with alizarin red S revealed the initiation site of the premetamorphic transformation of the larval skin into the adult precursor and its ensuing region-dependent expansion. The pre-adult skin first emerged at TK II to III (TK, Taylor and Kollros staging) t lateral sides of the body, which led us to postulate that 'the center for premetamorphic skin transformation' is formed at the specific site in this region. This center moved dorsally and then ventrally, then reached to the most proximal region of the tail, yielding a unique sequential conversion pattern by around TK V when the conversion was completed in the trunk. The present study also visualized the process of the hindlimb skin transformation.     

Spectrum of disease among HIV-infected adults hospitalised in a respiratory medicine unit in Abidjan, C?te d'Ivoire

SETTING: Respiratory medicine wards of the University Teaching Hospital, Abidjan, C?te d'Ivoire. OBJECTIVES: To describe the spectrum of opportunistic infection among human immunodeficiency virus (HIV) infected adults hospitalised in the respiratory medicine unit in Abidjan, and the level of immunosuppression at which these diseases occur. DESIGN: Cross-sectional study. RESULTS: Overall, 75% of patients were HIV-positive: among these patients, the most frequent diagnosis was tuberculosis, in 61%, followed by bacterial pneumonia (15%), Gram-negative septicaemia (particularly non-typhoid Salmonella) (9%) and empyema (5%). Atypical pneumonias appeared to be rare. Most HIV-positive patients had CD4 counts indicative of advanced immunosuppression: 36% had CD4 counts below 100 x 10(6)/l, 19% between 100 and 199 x 10(6)/l, 29% between 200 and 499 x 10(6)/l, and 16% above 500 x 10(6)/l. Overall in-hospital mortality was 27% for HIV-positive patients and 22% for HIV-negative patients (P = 0.5). In a multivariate analysis, the strongest independent risk factors for death were cachexia (odds ratio [OR] 7.4, 95% confidence interval [CI] 2.1-26.3), male sex (OR 4.5, 95% CI 1.2-17.4) and age over 40 (OR 4.1, 95% CI 1.0-17.2). CONCLUSIONS: Tuberculosis and bacterial infections are the major causes of respiratory morbidity in immunosuppressed HIV-infected adults in this population. Efforts to improve the management of HIV-related disease need to focus on prevention and treatment of these infections.     

Cytology of cervical chordoma in cerebrospinal fluid from a child. A case report

The cytologic findings on cerebrospinal fluid examination of cervical chordoma in a 2-year-old girl are presented. The major cell type was a small, isolated, hyperchromatic cell with sharply defined nuclear membrane and granular cytoplasm. However, the characteristic cell of this neoplasm, the so-called physaliferous cell with typical bubbly cytoplasm, was also noted. Cytologic findings were compared to biopsy findings, with a good correlation of tumor morphology. Clinical follow-up revealed unusually aggressive tumor behavior, and the patient died a year later despite intensive chemotherapy. The differential diagnosis of the condition is also discussed.     

Glyphosate is an inhibitor of plant cytochrome P450: functional expression of Thlaspi arvensae cytochrome P45071B1/reductase fusion protein in Escherichia coli

Radiofrequency (RF) energy has many advantages in thermal tumor ablation protocols. With the recent development of open MRI systems, interventional MRI procedures, including thermal ablation, have become the focus of great research interest. However, the significant interference between RF generators and MR imagers has prevented simultaneous imaging and RF ablation and, until now, has limited the role of RF-based thermal therapy in interventional MRI. Here, a simple switching circuit designed with consideration of patient safety provides compatibility between open MRI systems and RF thermal lesion generators. The experimental results show that the switching circuit allows imaging during RF ablation and opens new opportunity for MR-guided thermal therapy.     

GB virus C/hepatitis G virus infection among patients with hepatocellular carcinoma in the inshore area of the Yangtze River, China

The latest meeting of the AAMC's Forum on the Future of Academic Medicine, on April 29, 1998, opened with a talk by Francis S. Collins, MD, PhD, director of the National Human Genome Research Institute, who reviewed the significant progress that the Human Genome Project (HGP) has made and speculated on how genetic discoveries and technologies would transform health-related research and ultimately the practice of medicine. The HGP's findings will offer clear improvements in diagnosis and prevention, and eventually in treatments, and the relationship between the academic medical center and the pharmaceutical industry will change--but remain good--as that industry applies the findings of the HGP. He stressed the need for the public and health care providers to develop a greater understanding of genetic issues, and urged changes in medical education to accomplish this. Forum members and Dr. Collins discussed the ethics and economics in patient care resulting from genetic research; forum members also asked whether academic medical centers could profit from genetic research findings. The second speaker was John Eisenberg, MD, administrator of the Agency for Health Care Policy and Research, which fosters health care research and disseminates to clinicians and others the findings of such research. Among other topics, Dr. Eisenberg described the new emphasis on health care outcomes and quality and described how his agency promotes research in these areas. Forum members asked who would pay for the information systems needed to communicate the findings of health services research and also noted that there is an expanding definition of health that places new pressures on already stressed academic medical centers, their missions, and their curricula, which must change. Michael Whitcomb, MD, of the AAMC, noted that the view that medical schools can't change their curricula has been proved wrong, and that 24 medical schools are working with the AAMC's Medical Schools Objectives Project on curricular reform. The forum closed with discussion of a few broader issues affecting academic medical centers.