Evaluation of PLED as a chelating ligand in the preparation of gallium and indium radiopharmaceuticals

The 68Ga and 111In complexes of PLED (N,N'-dipyridoxylethylenediamine-N,N'-diacetic acid) were prepared and their biodistribution determined as a function of time following i.v. injection into rats. The 68Ga and 111In complexes behaved identically and were rapidly cleared from the blood via the kidneys into the urine. Similar rapid urinary excretion was observed in the gamma images obtained from a stump-tailed macaque injected with 111In-PLED. Paper electrophoresis at pH 7.35 showed a single radioactive peak for 111In-PLED which migrated towards the anode. PLED administered by i.p. injection was found to speed the blood pool clearance of previously administered 67Ga-citrate.

Treatment of critical neonatal edema with hemo-ultrafiltration

Three neonates with extreme edema associated with cardiovascular and renal insufficiency were treated with hemo-ultrafiltration for removal of critical edema fluid. In each patient peritoneal dialysis had not been effective in expedient fluid removal. Ultrafiltration was accomplished by occlusion of the proximal dialysate portal of a Travenol EX12-11, 0.8 m2 dialyzer and the application of vacuum suction to the distal portal. Blood flow ranged from 10-25 ml/min. The rate of ultrafiltration averaged 0.57 ml/kg/min resulting in losses of 4-16% of body weight. Episodes of hypotension were associated with too rapid ultrafiltration rate and not total volume removed. All patients tolerated the procedure. Two of the three patients demonstrated improvement in blood pressure, oxygenation and urine flow following the ultrafiltration. Ultrafiltration in the newborn may be a useful therapeutic procedure when conventional treatment fails.

The effects of acetaldehyde and acrolein on blood pressure in guanethidine-pretreated hypertensive rats

These experiments were undertaken to study the effect of the interaction of the antihypertensive agent guanethidine and two aldehydes possessing sympathomimetic activity on the blood pressure of spontaneously hypertensive rats (SHR). Acetaldehyde, when administered iv to acutely guanethidine-pretreated (15 mg/kg) SHRs under urethane anesthesia, caused a potentiated pressor response in the dose range of 3 to 40 mg/kg. When administered iv to chronically guanethidine-pretreated SHRs, a pressor response was noted at low doses and a depressor response at high doses. Acrolein (0.05 to 0.5 mg/kg) produced a pressor response at low doses and a depressor response at high doses in both acutely and chronically guanethidine-pretreated SHRs. Pressor responses, particularly to acetaldehyde, may be due to an enlarged tyramine-releasable pool, hyperreactivity of alpha adrenergic receptors of SHRs, or guanethidine inhibition of norepinephrine reuptake. Depressor responses to high doses of aldehydes may be attributed to vagal stimulation or direct vasodilation. It is concluded that there is a significant interaction between the aldehydes and guanethidine which may have implications for someone undergoing treatment with guanethidine for hypertension while being exposed to acetaldehyde and related compounds from ethanol and tobacco smoke.

Effects of intravenous acetaldehyde, acrolein, formaldehyde and propionaldehyde on arterial blood pressure following acute guanethidine treatment

Guanethidine (G) is currently used in the treatment of essential hypertension. Acetaldehyde (A), acrolein (AR), formaldehyde (F) and propionaldehyde (P) are constituents of cigarette smoke and (A) is also an intermediate oxidative metabolite of ethanol. These aldehydes are known to produce sympathomimetic effects by the release of NE from adrenergic neurons and to exert cardioinhibitory effects. The type of predominant effect is dose-dependent. This study was undertaken to determine if these aldehydes result in sympathomimetic effects in the presence of G (15 mg/kg iv) in anesthetized rats. G enhanced the pressor responses to A and P in dose ranges of 5-20 and 5-10 mg/kg respectively. However, AR and F at dose ranges of 0.05-5 and 0.1-10 mg/kg, respectively, elicited only depressor responses after G. Thus, A and P exerted greater sympathomimetic effects through the release of intraneuronal NE in the presence of G. The adrenergic neuronal blocking action of G changes the blood pressure effects of AR and F. When these two compounds are administered in the absence of G, they cause predominant pressor effects, whereas in the presence of G a depressor response is noted. This depressor response is possibly by vagal stimulation and/or direct vasodilation.

Spinal cord monitoring during spinal surgery using somatosensory spinal evoked potentials

Intraoperative monitoring of spinal cord function has been carried out in 59 patients during spinal instrumentation for scoliosis. Posterior tibial nerve stimulation in the popliteal space was performed and spinal evoked potentials from electrodes in the spinous processes observed. A rod artifact problem causing partial obliteration of the wave form can be minimized or eliminated by careful selection of the insertion of the fixation device. A drop in amplitude of the signal occurred in many of the tracings from control to distraction observations but did not result in neurologic deficit. One patient had a loss of the signal after maximum distraction with a Harrington rod and a return with release of distraction. This patient awoke with paralytic urinary bladder retention which resolved spontaneously but no other neurologic deficit. This method has been used for monitoring of spinal cord function during Harrington rod instrumentation, using both compression and distraction systems as well as Luque rod instrumentation. This method is safe, simple, and provides consistent and predictable wave forms; it appears to be reliable in indicating continuation of spinal cord function during the procedure.

Sudden and suspicious deaths outside the deceased's own country--time for an international protocol

Increased leisure time, international business commitments, and ease of travel have led to an increased incidence of sudden deaths outside the deceased's own country. Methods of investigation of sudden death, and the extent of such enquiries, vary greatly from country to country. The relatives of the decreased frequently make serious allegations relating to the circumstances of the death when they return to their homeland, and when the body is repatriated, a local pathologist may be directed to make an examination. This is frequently limited by inadequate police information, inadequate preservation of the organs and the absence of any autopsy report. Examples of these difficulties are presented, and suggestions offered for a basic protocol for the examination and report upon the death of a foreign national. Following the presentation of this paper at the International Association of Forensic Sciences Meeting in Bergen, considerable discussion took place and there have been further developments in the United Kingdom. These are briefly reported.

Zinc and wound healing

A review of the literature on zinc and wound healing shows the many gaps of knowledge which still exist. This study of the histologic appearance of wound healing in rats fed various diets demonstrates the serum zinc levels achieved by such diets. No significant improvement was observed in the rate of healing for any one group, but a number of histologic differences were observed.