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.      

Pathomechanics of structural foot deformities

This article presents the most common structural foot deformities encountered in clinical practice. The deformities are defined, and the expected compensations at the subtalar joint (STJ) are described. The theoretical consequences of the STJ compensations on proximal and distal tissues are presented. A biomechanical rationale for certain tissue disorders is described. The possible effects of abnormal STJ compensation on osseous development are briefly discussed.     

The effect of TNFa on bradykinin receptor binding, phosphatidylinositol turnover and cell growth in human A431 epidermoid carcinoma cells.

In this study, we examined the effect of TNFa on bradykinin (BK) B2 receptor binding and function in human A431 epidermoid carcinoma cells. [3H]BK binds to a single class of receptors on A431 cells in a saturable and reversible manner. A binding affinity (KD) of 3.0 +/- 0.3 nM (n = 4) and a Bmax of 151 +/- 14 fmols/10(6) cells, representing approximately 90,000 BK receptors per cell, was observed. The rank order of potency for BK agonist peptides indicates that the A431 BK receptor appears to be of the B2 subtype. When A431 cells were incubated with TNFa (10 ng/ml) for 48 h prior to BK binding, a significant decrease in the number of BK receptors compared to control was observed. TNFa did not influence the affinity of BK binding to A431 cells and direct addition of TNFa to the binding assay did not effect BK binding. BK-stimulated IP1 formation appeared to be increased in TNFa treated cells compared to control whereas histamine-stimulated IP1 formation was not influenced. Both control and TNFa treated cells were greater than 95% viable. However, TNFa treated cells were blocked in the G1 phase of the cell cycle resulting in a decrease in DNA synthesis. This may be one mechanism for the TNFa-induced decrease in BK receptors in A431 cells.