Acute respiratory distress in a bleomycin primed patient: a new use for nitric oxide

We describe the use of nitric oxide as an oxygen-sparing strategy in the context of prior bleomycin exposure. A 27-year-old male, previously treated with bleomycin for a testicular germ cell tumour presented with severe acute respiratory distress syndrome on the second postoperative day following an extensive retroperitoneal dissection. The mechanism of bleomycin toxicity and potential benefits of nitric oxide in this situation are considered.     

The use of cardiopulmonary resuscitation: how nephrologists and internists differ

We performed a national survey to explore the circumstances under which general internists and nephrologists discuss cardiopulmonary resuscitation (CPR) with patients and the factors influencing physician decisions to open such discussions. We wondered whether nephrology fellowship training and/or formal exposure to an ethics course during training altered physicians' use of CPR. Significantly more nephrologists than internists responded to the study (nephrologists, 174/467; internists, 92/380; P less than 0.01). Few of the respondents participated in an ethics course during training (9% of nephrologists, 15% of internists; P = NS), and fewer than half (26% of nephrologists, 37% of internists; P = NS) had engaged in formal discussions about initiating and withdrawing life-sustaining treatment during their training. Nephrologists spent significantly more time caring for patients in intensive care units (ICUs) (29% v 21% of time, P less than 0.05), and more often discussed CPR during their first meeting with a patient (7% of nephrologists v 1% of internists; P less than 0.05). Twenty-eight percent of nephrologists and 19% of internists thought CPR should be offered to all patients. Both nephrologists and internists rated neurologic dysfunction as the most important and age the least important factor influencing decisions to terminate CPR. Nephrologists were less comfortable than internists with healthy dialysis patients' decisions to refuse CPR. We conclude that nephrologists are more inclined than internists to use CPR in dialysis patients, in patients with impaired functional status, and in all patients. Training in medical ethics did not account for the differences among nephrologists and internists.     

Astrocyte characterization in the multiple sclerosis glial scar

Introduction:  Dense astrocytic scarring in chronic multiple sclerosis (MS) plaques inhibits tissue repair. However, at the rim of a lesion the glial scar fails to form despite the presence of reactive astrocytes. Animal studies have shown that astrocyte antigen expression varies depending on astrocyte type and location. Characterization of human astrocytes in MS tissue may identify markers relevant to the glial scar.
Materials and methods:  Astrocyte antigenic phenotype was investigated in subventricular white matter by immunocytochemistry and Western blotting. Snap-frozen tissue from normal controls ( n  = 4), MS normal appearing white matter ( n  = 5) and lesions [acute ( n  = 7), subacute ( n  = 7) and chronic ( n  = 13)] was studied.
Results:  As expected, glial fibrillary acidic protein and vimentin expression was elevated in scar astrocytes. In addition there was increased expression of nestin, embryonic neural cell adhesion molecule, epidermal growth factor receptor, nerve growth factor and its receptor p75, and in a subpopulation of scar astrocytes, basic fibroblast growth factor.
Conclusion:  Changes in expression of proteins associated with development, growth factors and growth factor receptors are characteristic of the scar astrocyte phenotype in chronic MS lesions. These proteins may be of relevance to glial scar formation and tissue repair.     

Antibiotic resistance among clinical isolates of Haemophilus influenzae in the United States in 1994 and 1995 and detection of beta-lactamase-positive strains resistant to amoxicillin-clavulanate: results of a national multicenter surveillance study.

A total of 1,537 clinical isolates of Haemophilus influenzae were recovered in 30 U.S. medical center laboratories between 1 November 1994 and 30 April 1995 and were characterized in a central laboratory with respect to serotype and beta-lactamase production and the in vitro activities of 15 oral antimicrobial agents. Overall, 36.4% of the isolates were found to produce beta-lactamase. The rank order of activity of six cephalosporins on the basis of MICs was cefixime > cefpodoxime > cefuroxime > loracarbef > or = cefaclor > cefprozil. On the basis of current National Committee for Clinical Laboratory Standards (NCCLS) breakpoints ages of isolates found to be resistant or intermediate to these agents were as follows: 0.1, 0.3, 6.4, 16.3, 18.3, and 29.8, respectively (National Committee for Clinical Laboratory Standards. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically, 4th ed. M7-A4, 1995). Azithromycin was, on a weight basis, the most potent of the macrolides tested in this study, followed by erythromycin and then clarithromycin. Azithromycin was typically fourfold more active than erythromycin, which was, in turn, slightly more active than clarithromycin. However, when compared on the basis of the frequency of resistance determined by using current NCCLS breakpoints, there was essentially no difference between azithromycin and clarithromycin, i.e., 0.5 and 1.9%, respectively (P = 0.086). Interpretive breakpoints for erythromycin MIC tests versus H. influenzae have not been developed. Resistance to other non- beta-lactam agents was variable, as follows: trimethoprim-sulfamethoxazole, 9.0%; chloramphenicol, 0.2%; tetracycline, 1.3%; and rifampin, 0.3%. Two conspicuous findings in this study were the identification of 39 strains H. influenzae that were beta-lactamase negative but ampicillin intermediate or resistant (BLNAR) and, even more surprisingly, 17 beta-lactamase-positive isolates that were resistant to amoxicillin-clavulanate (BLPACR). Strains of H. influenzae in the first group have heretofore been very uncommon; organisms in the second group have not previously been described in the literature. The percentages of all study isolates comprised of BLNAR and BLPACR organisms were 2.5 and 1.1, respectively. Overall resistance to ampicillin was thus 38.9%, and that to amoxicillin-clavulanate was 4.5%.     

Enteral tube feeding in a cohort of chronic hemodialysis patients.

Malnutrition affects up to half of all chronic dialysis patients and is an important predictor of mortality, but the efficacy of interventions designed to improve the nutritional status of dialysis patients has been poorly studied. Specifically, although enteral tube feeding is often cited as an important option in the treatment of malnourished dialysis patients, there are few studies examining the effectiveness and complications of enteral tube feedings in adults on dialysis. We performed a retrospective analysis of a small cohort (n = 10) of chronic hemodialysis patients who received enteral tube feeding as all or part of their nutrition between January 1 and May 1, 1999, with follow-up through May 1, 2000, to assess the efficacy and complications of enteral tube feeding. Six patients received feeding via a peritoneoscopically placed (PEG) tube, 3 via nasogastric (NG) tube, and 1 patient was switched from PEG to NG feeding after an exit site infection developed at her PEG site. Seven patients received enteral feeding because of swallowing difficulties occurring after a cerebrovascular accident. Four patients were fed via enteral tube temporarily (相似文献   

The formation of strand breaks in DNA after high-LET irradiation: a comparison of data from in vitro and cellular systems

This paper presents a summary of our understanding to date of the formation of DNA strand breaks induced by highly energetic particle beams (high-LET radiation). We have compared our own recent data on the formation of strand breaks induced in DNA in an aqueous solution with our previous data and those of others available from the literature for similar lesions made in cellular DNA. When the strand break induction frequency, as number of breaks per Gy per unit DNA, is plotted against LET, a series of biological effect curves (one for each particle atomic number Z) is obtained. The frequency of the formation of single-strand breaks has an RBE of less than 1 for DNA in solution and for DNA in the cell; the frequency of the formation of double-strand breaks (dsb) also has an RBE of less than 1 for DNA in a solution containing low amounts of free radical scavenger(s), while the RBE can be greater than 1 in the 50-200 keV/microns range for cellular DNA. RBE values are with respect to X-rays or cobalt gamma-rays. In cells the level of unrejoined strand breaks is also highest in the 50-200 keV/microns range and may reach 25-35% of the initial break yield depending on particle energy and Z-value. These irreparable lesions include double-strand scissions and some form(s) of single-strand breaks. The data presented cover results obtained for helium to uranium particles, with an LET range of 16 to 160,000 keV/microns. When different biological end-points are compared a strong correlation is found between induction of dsb, chromosomal abnormalities and mutation induction.     

Monoclonal antibodies specific for endoplasmic membranes of mammalian cochlear outer hair cells

Summary Monoclonal antibodies were raisedin vitro against an antigen associated with the lateral cisternal membranes of outer hair cells. Two of the antibodies were class IgM and one of these retained its specific reactivity in tissue fixed with aldehydes and embedded in the resin LR White. Immunogold labelling for electron microscopy showed that the antigen was closely associated with the membranes rather than the cytoplasmic or lumenal regions of the cisternae. The third antibody was an IgG. All three weakly labelled a protein band with an apparent molecular weight of about 60 kD on a Western blot. The antibodies did not cross-react with any other cell in the organ of Corti, including the inner hair cells. Furthermore, they showed no cross-reactivity with skeletal muscle, kidney, gut, brain, skin, blood or retina from the guinea pig. The results suggest that the lateral cisternae in outer hair cells may be functionally different from those of inner hair cells. The antibodies may provide useful markers for outer hair cells in studies of hair cell regeneration.