Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography

The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.     

Maxillary sinusitis in adults: an evaluation of placebo-controlled double-blind trials

BACKGROUND: In general practice, acute sinusitis is frequently diagnosed and treated with antibiotics. OBJECTIVE: This study aimed to determine the evidence for the effectiveness of antibiotic treatment in acute maxillary sinusitis in adults by assessing the methodological quality of placebo-controlled double-blind randomized trials. METHOD: An evaluation by four raters through a 35-item scoring-scale for internal and external validity of all placebo-controlled double-blind randomized trials on acute sinusitis found between January 1966 and July 1996. RESULTS: Eighty-five trials were excluded because they were not placebo-controlled, double-blind, randomized, or were carried out in patients with chronic sinusitis or in children. The three remaining trials were performed in different populations (one in general practice) between 1973 and 1978. Only one study claimed superiority of antibiotic treatment. Different inclusion criteria and major outcome measures were used by the authors. The reliability of major outcome events was reported poorly or not at all and in two studies outcome measures were clinically inappropriate. The studies scored 30-62% of the maximum attainable score for internal validity and 10-20% for external validity. CONCLUSION: The effectiveness of antibiotic treatment in acute maxillary sinusitis in a general practice population is not based sufficiently on evidence.      

Convergence of occipital nerve and superior sagittal sinus input in the cervical spinal cord of the cat

Co-existence of facial and occipital pain may occur in occipital neuralgia, migraine and cluster headache; suggesting convergence of trigeminal and cervical afferents. Such convergence has been shown in humans and other animals, but the site and extent of this are uncertain. In anaesthetized adult cats, the superior sagittal sinus and occipital nerve were stimulated electrically, and extracellular recordings made in the dorsolateral area of the upper cervical cord using glass-coated tungsten electrodes. Of 49 units in 10 cats, 33 (67%) had input from the superior sagittal sinus and the occipital nerve. Thirteen (27%) had superior sagittal sinus input and 3 (6%) had occipital nerve input. Convergent receptive fields were identified mechanically in 7 units. These experiments in cats show convergent input from occipital nerve and superior sagittal sinus on dorsolateral area units in two-thirds of cases studied. This experimental site of trigeminocervical convergence may relate to referral of pain in occipital neuralgia and other headaches.     

Nonsteroidal anti-inflammatory drugs (NSAIDs) and the kidney

In patients with PG-dependent renal function, NSAID administration constantly reduces GFR and RBF in a dose-dependent fashion. In this situation, the risk of overt acute renal failure is high and should be taken into proper account. In contrast, the incidence of NSAID-related renal structural alterations appears to be very low, yet the absolute number of patients may be significant considering the wide use of such drugs. Concerning the antiproteinuric effect of NSAIDs, the unfavourable ratio risk/benefit does not seem to support their indication in proteinuric nephropathies. The development of PGHS-2 selective inhibitors is promising, and may open new therapeutical strategies in the treatment of the progression of renal disease.      

Tissue-specific extinguisher loci in the murine genome: A screening study based on a rat/mouse microcell hybrid panel

Extinction of tissue-specific traits in intertypic somatic cell hybrids is a well-known phenomenon. In the past few years, microcell hybrids have been used in attempts to dissect this phenotype genetically, and tissue-specific extinguisher loci have been mapped to two different mouse chromosomes. When transferred from fibroblasts into hepatoma cells by microcell fusion, these loci down-regulate expression of specific liver genes intrans. However, other liver genes that are extinguished in genotypically complete hybrids seem not to be extinguished in monochromosomal hybrids. To assess the generality of monochromosomal extinction phenotypes, we assembled a collection of rat hepatoma/mouse fibroblast microcell hybrids that represent most of the mouse chromosome complement, and we screened them for expression of a large number of liver-specific genes. Phosphoenolpyruvate carboxykinase gene expression was down-regulated in hybrids containing mouse chromosome 7 or mouse chromosome 11, but other extinction phenotypes were not readily apparent. These results indicate that extinction of many liver genes may be a polygenic trait.     

Mannose binding lectin and C3 act as recognition molecules for infectious agents in the vagina

In our study we examined the early complement components in patients with bacterial vaginosis (BV), vulvovaginal candidiasis (VVC) and in healthy controls. The levels of C1q, mannose-binding lectin (MBL) and C3 were measured by ELISA in the cervicovaginal lavage (CVL) from gynaecological patients and controls. No significant differences were observed in the levels of these proteins in the three study groups. Immunofluorescence analysis of the clue cells and Candida hyphae from BV and VVC patients for surface-bound complement components showed the presence of C3, while C1q was undetectable. MBL was revealed on clue cells but not on Candida. Binding of MBL to Candida, grown or cytocentrifuged from the CVL of VVC patients, was found to be pH dependent and occurred between pH 4.5 and pH 5.5. In conclusion, we demonstrated that MBL and C3 present in the vaginal cavity act as recognition molecules for infectious agents that colonize the cervicovaginal mucosa. Our finding that MBL, but not C1q, binds to bacteria and fungi in vagina suggests that the lectin and classical pathways of complement activation may play a different role in immune defence in the female genital tract.