Biomedical subjects
M Rosen
Publications and source records attributed to M Rosen.
Peripheral mechanical loading and the mechanism of the tremor of chronic alcoholism.
The tremor of chronic alcoholism, although clinically similar to essential tremor, has been considered a distinct syndrome. Its underlying mechanism was analyzed in five patients (none in the acute stages of alcohol withdrawal) hospitalized in an alcohol detoxification program. All five patients performed tracking tasks in which they pursued a linearly moving "target" light with a response light that they controlled by flexion-extension activity of the wrist. Stationary and dynamic targets were used with both isometric and unconstrained wrist mechanical interfaces. Frequency, torque, and displacement tremor characteristics were examined under varying inertial loading or isometric voluntary torque conditions. Two simultaneous tremor components were present in all patients: a prominent 4- to 7-Hz low-frequency peak and a smaller-amplitude 9.4- to 9.6-Hz high-frequency peak. As the inertia of the hand was augmented during unconstrained tasks, the low-frequency peak decreased, while the high-frequency peak was unaffected. As required voluntary effort was increased during isometric testing, the amplitude of the low-frequency peak increased. These findings suggest that the low-frequency peak represents the significant pathologic component of the tremor of chronic alcoholism and that it has a biomechanical reflex mechanism similar to that of the lower-amplitude normal physiologic tremor.
[Backache and the anesthetist].
Explore the source record for details and available documents.
The interaction of platinum antitumour drugs with mouse liver mitochondria.
A study was undertaken to determine if cis-DDP and its second generation derivatives produced effects on mouse liver mitochondria, and if any of the observed effects could be correlated with the nephrotoxicity of the drugs. Although changes were observed in mitochondrial morphology, enzyme activity, Ca2+ influx, terbium binding and surface potential, no specific effect was correlated with nephrotoxicity. cis-DDP produced marked changes in mitochondrial morphology; electron probe analysis showed binding of the drug to the mitochondria. Inhibition of complex I and II activity of the respiratory chain and an ionic-strength-dependent effect on Tb3+ (a Ca2+ analogue) fluorescence were observed. The non-nephrotoxic derivatives, CHIP and tetraplatin, also produced significant changes in morphology. Treatment with these derivatives also produced decreases in mitochondrial enzyme activity, but the effect on terbium binding had an ionic-strength dependence which was inverse to that observed with cis-DDP. The tetravalent compounds also had a notable effect on mitochondrial surface potential. Carboplatin had an effect on morphology and Ca2+ influx and it inhibited the respiratory enzymes, although in a manner different from that observed with cis-DDP. Carboplatin had a minimal effect on terbium binding. It is evident that if the platinum drugs enter a cell to exert their action at the nuclear level, they will also depress mitochondrial function. The observed effects did not correlate with nephrotoxicity but, since all four compounds significantly altered mitochondrial structure and function, they may be related to the cytotoxicity of the drug.
The effect of impression technique and multiple pours on accuracy of stone models.
Explore the source record for details and available documents.
Effects of intrathecal and intraperitoneal morphine on gastrointestinal motility in the rat.
A method has been developed to compare gastrointestinal (GI) transit time after intrathecal (i.t.) drug injection in the rat. Each animal had a catheter implanted in the i.t. space. Eight rats, on three separate occasions, had either i.t. morphine 16 micrograms kg-1 (in 50 microliters) or intraperitoneal (i.p.) morphine (0.1%) 7.5 mg kg-1 or i.t. saline (50 microliters). The dose of morphine was the ED50 for analgesia by each route. After halothane and oxygen anaesthesia, 10 steel balls and 1 ml of contrast medium were placed into the stomach, the whole procedure being completed within 5 min. Radiographs were taken at 5 min, 3, 6 and 24 h, and the number of balls in the stomach, small and large intestine were counted. The inhibitory effect of i.t. or i.p. morphine on gut motility caused an equally significant delay at 6 h. In a separate series of eight rats the delay by i.t. morphine could be completely antagonized by i.p. naloxone 1 mg kg-1. Thus, i.t. morphine in an analgesic dose even though smaller than the i.p. dose has a similar inhibitory effect on GI tract motility in the rat. This method would enable comparisons on GI transit to be made between a variety of intrathecally administered drugs.
Duplication of the upstream regulatory sequences increases the transformation potential of human papillomavirus type 11.
Infections with certain types of papillomaviruses, e.g., human papillomavirus type 16 (HPV-16), often progress to cancer. Malignant lesions associated with the closely related HPV-11 are extremely rare. Additionally, HPV-11 DNA, unlike HPV-16, does not normally transform cells in vitro. We determined that HPV-11 DNA was able to transform baby rat kidney cells in a ras-dependent focus assay when the upstream regulatory region (URR) was present in two copies. Addition of a second HPV-11 URR or an HPV-16 URR was equally effective and was position and orientation independent. The transformation was enhanced by dexamethasone. On passage the HPV-11 genome was not retained at a detectable level. This analysis supports isolated observations in vivo that duplications of regulatory sequences in HPV-11 increase the transformation potential of this virus type.
Obstetric anaesthetic and analgesic services in Wales.
Explore the source record for details and available documents.
Comparison of buprenorphine and pethidine given intravenously on demand to relieve postoperative pain.
In a double-blind study of on-demand intravenous analgesia buprenorphine was found to be about 600 times as potent as pethidine. The incidence of side effects was similar with both drugs. The quality of analgesia, subjectively assessed, was good with both drugs using this method of administration. Provided that its low potential for abuse is substantiated, buprenorphine appears to be a powerful analgesic that may successfully be given intravenously on demand.
Obstetric anaesthetic and analgesic services in Wales.
A survey of obstetric anaesthetic services in Wales covering 21 major units in which over 31 000 deliveries take place annually showed inadequacies in staffing at consultant and resident anaesthetist level. At least 20 additional consultant sessions were required to meet the recommendations of the Association of Anaesthetists of Great Britain and Ireland. If patients' requests for epidural analgesia are to be met some reorganisation and centralisation of facilities is needed.
The approaching doctor glut.
Explore the source record for details and available documents.
Antacids and cricoid pressure in the prevention of fatal aspiration syndrome.
Explore the source record for details and available documents.
Test-dose in extradural analgesia.
Explore the source record for details and available documents.
Self-administered intermittent nitrous oxide analgesia for labour. Enhancement of effect with continuous nasal inhalation of 50 per cent nitrous oxide (Entonox).
Explore the source record for details and available documents.
The Valved-Y-Cardiff Connector (V.Y.C. Con).
A disposable Y-connector for use when two infusions are connected to the same channula has been tested. The connector incorporates a valved tap in one limb which prevents retrograde flow into the infusion connected to that limb.