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.      

A programme for treating chemically dependent medical students

Summary. The first American programme for chemically dependent medical students at the University of Tennessee, Memphis is described. The goals of the Aid for the Impaired Medical Student (AIMS) Program are to provide confidential treatment for chemically dependent medical students, to assure that recovering students are able to resume their education, and to protect patients and others from the harm that may be caused by impaired students. The Program is administered by the AIMS Council, consisting of medical professionals and elected student representatives. The Council oversees the management of cases, including investigation of students who may be impaired, intervention when chemical dependency is suspected, diagnostic evaluation, treatment and aftercare, and post-recovery advocacy for students. The Program's experience includes 18 cases of suspected chemical dependency, with four self-referrals and 14 students referred by third parties. Eleven students have been diagnosed as chemically dependent and have completed treatment programmes. Nine have maintained recovery and eight have graduated. One student subsequently relapsed and committed suicide. Obstacles in programme implementation have involved absence of perceived need, the view that chemically dependent students should be dismissed from school, and reluctance of students to report classmates. Resources have included highly respected student representatives, a supportive administration, assistance of the impaired physicians programme, and medical insurance and professional courtesy to defray costs. Although the number treated has been modest, the AIMS Program is an important vehicle for training students regarding chemical dependency and their professional obligations toward impaired colleagues.     

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.      

TRANSIENT BRADYCARDIA ASSOCIATED WITH EXTRADURAL BLOOD PATCH AFTER INADVERTENT DURAL PUNCTURE IN PARTURIENTS

We have studied prospectively 10 ASA I or II postpartum patientsafter inadvertent dural puncture during labour. An extraduralblood patch (autologous blood 15 ml) was performed within 18h of delivery, with continuous EEG, upper facial EMG (Datex:Anesthesia and Brain Activity Monitor), pulse oximetry and heartrate measurement before, during and for 30 min after extraduralinjection. Non-invasive arterial pressure measurements (Dinamap)were recorded at 5-min intervals. After extradural blood patch,a statistically significant(Student's t test, P < 0.05) decreasein heart rate, from a mean baseline of 88.6 (SD 7.31) beat min^–1to 51.3 (7.6) beatmin^–1, occurred within 122.6 (16.9)s from the time of the EBP. Bradycardia was observed for a meanduration of 12.4 (1.1) s. Upper facial EMG, EEG, Sp02 and arterialpressure did not change.