Nanoprobe NMR spectroscopy and in vivo microdialysis: new analytical methods to study brain neurochemistry

Nuclear magnetic resonance (NMR) spectroscopy was used to study the chemical composition of cerebrospinal fluid (CSF) microdialysate from the rat brain. In vivo microdialysis techniques were used in several brain regions including the frontal cortex, amygdala, striatum, nucleus accumbens and third ventricle and dialysate samples (20microl) were subsequently analyzed by one and two-dimensional 1H NMR experiments using a Varian nanoprobe. Neurochemical resonances were assigned on the basis of published chemical shifts [Lindon et al., Ann. Rep. NMR Spectrosc. 38 (1999) 1-88], correlation experiments and addition of standard compounds. Glucose, lactate, formate, pyruvate, creatinine, gamma-hydroxybutyrate, acetate, glutamate, glycine, tyrosine, isoleucine, leucine, alanine and choline were some of the neurochemicals unambiguously assigned. Additional studies in the frontal cortex showed that amino acids such as glutamate, alanine and isoleucine were sensitive to local tetrodotoxin (TTX) infusion. The NMR spectra were also subjected to multivariate statistical methods to compare the different brain regions examined. To our knowledge, the present experiments are the first to describe the combination of nanoprobe NMR technology with in vivo microdialysis for the analysis of brain neurochemistry in freely-moving rats.     

Mast cell chymase is a possible mediator of neurogenic bladder fibrosis

AIMS: Urinary bladders of patients with myelomeningocele, owing to spina bifida, are often functionally impaired, fibrotic organs. Common to this condition are repeated occurrences of bladder infection and inflammation. Since mast cells have been associated with a fibrogenic response in inflammatory conditions, we investigated the role of mast cell granule product, chymase, as a mediator of myleodysplastic bladder fibrosis. METHODS: Human control and myelodysplastic bladder tissues were stained with Unna's stain and chymase antibody to determine mast cell number and localization. Cell specific localization of collagen mRNAs was determined by in situ hybridization (ISH). In vitro, normal human bladder fibroblasts were treated with recombinant chymase, heparin and inhibitors, and collagen subtype concentration was determined by enzyme linked immunosorbent assay (ELISA). RESULTS: Myelodysplastic bladders were characterized by increased mast cells in the detrusor muscle layer compared to control bladders, as well as mast cell degranulation and increased connective tissue deposition. Both types I and III collagen mRNA localized to fibroblasts surrounding detrusor muscle fascicles, whereas only collagen III mRNA localized to cells within connective tissue infiltrated muscle bundles in myelomeningocele bladder tissue. Chymase treatment of bladder fibroblasts, in vitro, was dose-dependent and resulted in significant increases in both types I and III collagen. Heparin did not alter collagen protein expression, whereas heparin-chymase combination modulated type III collagen expression. Serine protease inhibitor, phenylmethylsulfonlyfluoride, did not inhibit collagen synthesis, whereas denatured chymase resulted in decreased collagenous protein levels. CONCLUSIONS: Bladder fibrosis may be mediated by mast cell chymase stimulation of collagen synthesis.     

Botulinum toxin as a biological weapon: medical and public health management

OBJECTIVE: The Working Group on Civilian Biodefense has developed consensus-based recommendations for measures to be taken by medical and public health professionals if botulinum toxin is used as a biological weapon against a civilian population. PARTICIPANTS: The working group included 23 representatives from academic, government, and private institutions with expertise in public health, emergency management, and clinical medicine. EVIDENCE: The primary authors (S.S.A. and R.S.) searched OLDMEDLINE and MEDLINE (1960-March 1999) and their professional collections for literature concerning use of botulinum toxin as a bioweapon. The literature was reviewed, and opinions were sought from the working group and other experts on diagnosis and management of botulism. Additional MEDLINE searches were conducted through April 2000 during the review and revisions of the consensus statement. CONSENSUS PROCESS: The first draft of the working group's consensus statement was a synthesis of information obtained in the formal evidence-gathering process. The working group convened to review the first draft in May 1999. Working group members reviewed subsequent drafts and suggested additional revisions. The final statement incorporates all relevant evidence obtained in the literature search in conjunction with final consensus recommendations supported by all working group members. CONCLUSIONS: An aerosolized or foodborne botulinum toxin weapon would cause acute symmetric, descending flaccid paralysis with prominent bulbar palsies such as diplopia, dysarthria, dysphonia, and dysphagia that would typically present 12 to 72 hours after exposure. Effective response to a deliberate release of botulinum toxin will depend on timely clinical diagnosis, case reporting, and epidemiological investigation. Persons potentially exposed to botulinum toxin should be closely observed, and those with signs of botulism require prompt treatment with antitoxin and supportive care that may include assisted ventilation for weeks or months. Treatment with antitoxin should not be delayed for microbiological testing.     

Breast cancer risk factors: can we select women for prophylactic mastectomy?

Prophylactic procedures to prevent disease in women at high risk for breast cancer should be considered only when the benefits of prophylaxis outweigh its costs. The rational prophylactic use of mastectomy in these circumstances must await answers to several questions. First, accurate estimates of the true risk associated with these lesions must be obtained, as current estimates are imprecise and potentially biased. Second, large ongoing trials of breast cancer screening and treatment may provide effective methods of distinguishing those women at exceptionally high risk in whom such procedures may be warranted. Finally, the question of conservative surgery as an acceptable treatment for breast cancer must be settled; otherwise, the prophylactic procedure may be more invasive and disfiguring than the treatment of the disease it seeks to prevent.     

The Vancouver Lymphadenopathy - AIDS Study: 2. Seroepidemiology of HTLV-III antibody

Testing for antibody to human T-lymphotropic retrovirus (HTLV-III) was carried out in 448 participants in the Vancouver Lymphadenopathy-AIDS (acquired immune deficiency syndrome) Study. The overall prevalence rate of seropositivity was 34%. Of 130 seronegative subjects followed for an average of 8.5 months, 14 became seropositive; thus, the approximate annual seroconversion rate was 15%. More than 100 male sexual partners in one's lifetime, frequent receptive anal intercourse, fisting, a history of gonorrhea or hepatitis, and frequent sexual contact in clubs were found to be independent risk factors for HTLV-III seropositivity.     

Cigarette smoking and breast cancer: a case-control study of screening program participants

A case-control study of Canadian women aged 40-59 years (n = 123; 369) has been conducted on the relationship of cigarette-smoking and initial visit breast cancer detection within a multicenter screening program. Among premenopausal women, a relative risk of 2.1 (1.1, 4.0) was found for ever-smokers versus never-smokers. There was a dose-response gradient with relative risks of 1.0, 1.3, 2.5, and 3.5 among women with 0, 1-200, 201-500, and greater than 500 cigarette-years of exposure, respectively. No overall association was detected among postmenopausal women but a significant interaction with parity was present in this group. When menopausal status was ignored, there was a nonsignificantly elevated risk of 1.4 (0.9, 2.1) for ever- versus never-smokers but the dose-response was significant with relative risks of 1.0, 0.9, 1.7, and 2.0 in the above four exposure categories, respectively. These results persisted despite adjustment for several important variables. These data are consistent with an interaction of smoking and participation in the screening study or with a possible etiologic role for smoking. Even if smoking is not related to breast cancer etiologically, these data still suggest that smokers who visit screening centers have an elevated risk of breast cancer detection on initial visit, especially among premenopausal women. They do not support the hypothesis of a protective effect of smoking and underscore the need for further study into this important relationship.