Haemodynamic changes in ipsilateral and contralateral fingers caused by acute exposures to hand transmitted vibration.

OBJECTIVES: To investigate changes in digital circulation during and after exposure to hand transmitted vibration. By studying two frequencies and two magnitudes of vibration, to investigate the extent to which haemodynamic changes depend on the vibration frequency, the vibration acceleration, and the vibration velocity. METHODS: Finger skin temperature (FST), finger blood flow (FBF), and finger systolic pressure were measured in the fingers of both hands in eight healthy men. Indices of digital vasomotor tone-such as critical closing pressure and vascular resistance-were estimated by pressure-flow curves obtained with different hand heights. With a static load of 10 N, the right hand was exposed for 30 minutes to each of the following root mean squared (rms) acceleration magnitudes and frequencies of vertical vibration: 22 m.s-2 at 31.5 Hz, 22 m.s-2 at 125 Hz, and 87 m.s-2 at 125 Hz. A control condition consisted of exposure to the static load only. The measures of digital circulation and vasomotor tone were taken before exposure to the vibration and the static load, and at 0, 20, 40, and 60 minutes after the end of each exposure. RESULTS: Exposure to static load caused no significant changes in FST, FBF, or indices of vasomotor tone in either the vibrated right middle finger or the non-vibrated left middle finger. In both fingers, exposure to vibration of 125 Hz and 22 m.s-2 produced a greater reduction in FBF and a greater increase in vasomotor tone than did vibration of 31.5 Hz and 22 m.s-2. In the vibrated right finger, exposure to vibration of 125 Hz and 87 m.s-2 provoked an immediate vasodilation which was followed by vasoconstriction during recovery. The non-vibrated left finger showed a significant increase in vasomotor tone throughout the 60 minute period after the end of vibration exposure. CONCLUSIONS: The digital circulatory response to acute vibration depends upon the magnitude and frequency of the vibration stimulus. Vasomotor mechanisms, mediated both centrally and locally, are involved in the reaction of digital vessels to acute vibration. The pattern of the haemodynamic changes in the fingers exposed to the vibration frequencies used in this study do not seem to support the frequency weighting assumed in the current international standard ISO 5349.     

La vérification ultime au lit du malade: résultats d''une enquête nationale sur les réactifs et dispositifs utilisés en France

The national reference Center for blood groups checked samples of reagents and devices used in France for a definitive verification of pretransfusion ABO tests performed at the patient's bedside, as defined by French health authority regulations. The results of an initial inquiry was published in 1991. The new study shows no significant improvement of the quality of reagents and devices. This is a major concern considering the importance of ABO incompatibility in severe hemolytic transfusion reactions.     

Molecular conformation of estramustine and two analogues.

The crystal and molecular structures of estramustine and two of its analogues have been determined by X-ray crystallographic techniques (a total of three different compounds). The compounds studied are estramustine [1,3,5(10)-estratriene-3,17 beta-diol-3-N,N-bis(2'- chloroethyl)carbamate] and its monohydrate, estromustine [17-oxo-1,3,5(10)-estratriene-3-yl-N,N-bis(2'-chloroethyl)carbamate], and 17-oxo-5-androsten-3 beta-yl-N,N-bis(2'-chloroethyl)carbamate. Three views of estramustine were obtained from the study of its two crystal forms. The main structural features found are as follows: (a) the geometries of the steroid moieties are closely similar to those of the parent steroids, (b) the bonds around the nitrogen atom of the nitrogen mustard grouping lie approximately in a plane in each structure, (c) the plane through the carbon atoms of the steroid A-ring lies approximately perpendicular to the plane through the carbamate atoms in each structure, (d) the carbonyl C-O of the carbamate points to the alpha side of the steroid moiety in each structure, and (e) one chlorine atom of the nitrogen mustard grouping makes a close contact [3.13 A], in each structure, to the nitrogen atom. Hydrogen bonding to the carbamate appears to occur from the alpha side of the steroid; there is no hydrogen bonding to the nitrogen atom of the carbamate group. These structural data provide some steric explanations for the resistance of the carbamate to enzymatic hydrolysis. The long in vivo half-life of the intact estramustine molecule is a result of this stability. This is responsible for the absence of alkylating ability and the propensity of the drug to bind microtubule-associated proteins and express an antimitotic mechanism of action.     

Fixed drug eruption from piroxicam

The pathogenetic mechanism of fixed drug eruption (FDE) is still unknown. One of the most common causes of FDE is the use of nonsteroidal antiinflammatory drugs (NSAIDs). Oxicams are in the NSAID group and piroxicam is one of the most used of these drugs. FDE caused by piroxicam is rare but a few cases have been reported. Patch tests are useful for diagnosing some cases of FDE; they give variable results on previously affected skin while no reaction appears on unaffected skin. Some cases of cross-sensitivity among piroxicam and other substances have been reported. We report two new cases of FDE due to piroxicam with negative patch test on normal skin and positive results on affected skin.     

Effects of ibogaine on naloxone-precipitated withdrawal in morphine-dependent mice

In naive mice, ibogaine at a tremorigenic dose (30 mg/kg, ip), did not produce antinociception but did potentiate the antinociceptive potency of morphine in the tail-flick test. In morphine-dependent mice, ibogaine did not eliminate withdrawal symptoms but significantly increased the number of repetitive vertical jumps induced by naloxone, whatever the duration of the chronic morphine treatment. By comparison, repetitive jumping induced by alpha-napthoxyacetic acid (alpha-NOAA), a non-convulsant drug which induced jumping without affecting other morphine-withdrawal signs, was not significantly modified by ibogaine. These results indicate that while acute antinociceptive effects of morphine are modulated by ibogaine, this drug, shown to alleviate opiate dependence in man, does not attenuate in mice opioid withdrawal manifestations.     

Plasma iron status and lipid peroxidation following thrombolytic therapy for acute myocardial infarction

Summary— Free radical species have been implicated as important agents involved in myocardial ischemic and reperfusion injuries. Superoxide is capable of mobilizing iron from ferritin and the released iron can cause hydroxyl formation from H₂O₂. The aim of this study was to evaluate the time-dependent increase in lipid peroxidation assessed by plasma thiobarbituric acid reactive substances (TBARS) and the relationship between lipid-peroxidation and the iron status. Peripheral venous blood samples were obtained from 17 men with acute myocardial infarction (AMI) before thrombolytic treatment (T0***) and 1, 2, 3, 4, 8, 12, 16, 20, 24 and 48 hours after commencing fibrinolytic treatment. The concentration of TBARS, the parameters of iron metabolism, serum myoglobin, creatine kinase, and creatine kinase-MB were measured. Early reperfusion was judged by regression of sinus tachycardia (ST) elevation and reduction of chest pain. Recanalization of coronary artery was evaluated by a late coronary angiography 24–96 hours after thrombolysis. After thrombolytic therapy, the TBARS level was raised from 2.98 ± 0.80 (T0***) to 4.57 ± 1.24 (peak), and decreased to 2.96 ± 0.40 nmol/mL plasma at T48 (T0 vs peak: P < 0.001, peak vs T48: P < 0.001, TO vs T48: NS). The mean time of the peak was observed at 9.7 ± 7.5 hours. The iron increased significantly from 0.67 ± 0.34 (T0) to 1.15 ± 0.52 mg/L (peak), and returned to the pre-reperfusion to levels: 0.53 ± 0.28 UI/L at T48 (T0 vs peak: P < 0.001, peak vs T48: P < 0.001, TO vs T48: NS). The mean time of the peak was observed at 9.4 ± 7.3 hours. In return, no correlation was found between the increase of plasma creatine-kinase activity, myoglobin and iron or between the biochemical markers and time of fibrinolytic therapy. The results confirmed the importance of the temporal relationship between lipid peroxidation and iron status after thrombolytic therapy. Our results are in agreement with the concept that antioxidant agents used in association with thrombolytic therapy might be useful.     

In vitro elution characteristics of commercially and noncommercially prepared antibiotic PMMA beads.

The successful treatment of osteomyelitis with commercially prepared gentamicin-polymethylmethacrylate (PMMA) (Septopal) beads and surgical debridement has led to the use of this technique in the United States. However, commercially prepared gentamicin-PMMA beads are not currently available to orthopedic surgeons in the United States. Therefore, these surgeons commonly manufacture their own antibiotic-containing cement beads in the operating room at the time of surgery. There is little data that compare the antibiotic elution characteristics of such preparations to commercially prepared gentamicin-PMMA beads. This study compares the measured amount of antibiotic elution of either gentamicin or tobramycin from laboratory manufactured Zimmer, Simplex, or Palacos beads to commercially prepared gentamicin-PMMA (Septopal) beads. During a 30-day study period, commercially prepared gentamicin-PMMA beads eluted more total antibiotic and maintain higher concentrations than did antibiotic acrylic composites manufactured in the authors' laboratory.