Retinopathy of prematurity in infants less than 29 weeks' gestation at birth

From January 1986 to December 1991 we examined the eyes of 206 infants born at Westmead Hospital, Neonatal Intensive Care Unit who were less than 29 weeks' gestation at birth to determine the incidence of retinopathy of prematurity. Eighty-five infants (41.3%) had no retinopathy of prematurity (ROP) in either eye, 82 infants had stages 1 or 2 ROP (39.8%), 29 had stage 3 ROP (14.1%) and 11 had stage 4 ROP (5.3%). Of these, cryotherapy was performed in 18; six now have bilateral retinal detachment and are blind The more severe stages of ROP were significantly associated with an increase in the number of days of oxygen supplementation, an increase in the number of days of mechanical ventilation and the presence of patent ductus arteriosus. Infants receiving steroids for mechanical ventilator dependence had a significantly greater chance of requiring cryotherapy (11 or 22 receiving steroids versus seven of 43 without steroids; P < 0.01).     

Metabolism of the leukotriene receptor antagonist 5-(2-(8-phenyloctyl)phenyl)-4,6-dithianonanedioic acid (SK&F 102922) in the guinea pig. Rearrangement of the acyl glucuronide.

A primary route of inactivation of leukotrienes and their receptor antagonists (LTRA) is metabolism by omega oxidation. SK&F 102922 [5-(2-(8-phenyloctyl)phenyl)-4,6-dithianonanedioic acid] is a LTRA that was designed to be resistant to omega oxidation. Therefore, these experiments were designed to characterize the metabolic fate of [14C]SK&F 102922. Following iv administration of SK&F 102922 (5 mg/kg), 80% of injected radioactivity was excreted in bile in 1 hr. At least five metabolites and parent (18% of administered dose) were present in bile. One metabolite (M1), which accounted for less than 10% of the excreted radioactivity, was monohydroxylated. Three metabolites (M2, M3A, and M3B), which together accounted for greater than 50% of excreted radioactivity, had mass spectra consistent with acyl glucuronides. All three metabolites were alkali labile, whereas only one metabolite (M2) was susceptible to beta-glucuronidase hydrolysis. These data indicate that M3a and M3b are nonglycosidic isomers of M2 that were formed by a nonenzymic reaction involving migration of the aglycone (SK&F 102922) from C-1 to C-2, C-3, or C-4 of glucuronic acid. The 1-O-acyl-beta-glucuronide of SK&F 102922 (M2) exhibits pH dependent rearrangement, with half-lives ranging from 1 to greater than 1000 hr. Therefore, acyl glucuronidation can account for much of the metabolic fate of SK&F 102922 and, potentially, other structurally related LTRAs or endogenous leukotrienes themselves.     

A Thalamic Contribution to Arousal-induced, Non-photic Entrainment of the Circadian Clock of the Syrian Hamster

It is well established that the circadian clock of the suprachiasmatic nuclei (SCN) is entrained by light. More recently, the potent effects of arousing, non-photic cues on the clock have been recognized. The neural mediators of non-photic entrainment are yet to be identified. To examine the contribution of the thalamic intergeniculate leaflet (IGL) and its NPY-immunopositive projection, the geniculo-hypothalamic tract to non-photic entrainment by arousal, male Syrian hamsters received lesions of the IGL (IGLX) which ablated NPY-immunoreactivity in the SCN. Their circadian responses to both photic and non-photic cues were then tested. Lesions resulted in a delay in the timing of activity onset following lights out, but had no effect on the behavioural or cellular circadian responses to phase-advancing light pulses presented at circadian time (CT) CT19 (where CT12 represents the time of activity onset). Injection with a benzodiazepine (chlordiazepoxide, 100 mg/kg) at CT6 suppressed wheel-running, increased general locomotion of intact controls and induced large phase advances of the circadian rhythm of wheel-running. Chlordiazepoxide also inhibited wheel-running in lesioned animals, but there was no significant increase in general locomotion and the lesioned animals did not phase advance. Serial arousal by injection of saline at intervals of 23.5 h for 6 days entrained the circadian rhythm of wheel-running of intact hamsters and was associated with an increase in general locomotor activity. Entrainment by serial arousal was abolished by IGLX. However, the lesioned animals did show a clear behavioural response to every presentation of the non-photic cue. These results show that the IGL is a necessary component of the neural pathways mediating both arousal- and benzodiazepine-induced non-photic entrainment.     

Human metabolism of arsenobetaine ingested with fish

1. Six volunteers ingested 74As-labelled arsenobetaine with a fish meal. The retention and distribution of the tracer were studied by body radioactivity measurements. 2. The tracer became rapidly dispersed in soft tissues, with no major concentration in any localized organ or region. 3. In all subjects less than 1% of the ingested activity remained in the body after 24 days. 4. Any losses from the skin were minor in relation to those by other routes of excretion.     

Use of suture-mediated vascular closure devices for the management of femoral vein access after transcatheter procedures.

Groin complications remain the most common complication of cardiac catheterization procedures. While the use of closure devices is increasing for arterial sheaths, venous sheaths tend to be removed and hemostasis achieved with manual compression. We report our experience using Perclose suture-mediated vascular closure device to achieve hemostasis and early mobility in patients who have had venous access as part of their procedure. There were a total of 42 patients (21 males; average age, 63.5 years) studied. The majority of the patients had 7 Fr sheaths (24), with access sites of sheaths up to 14 Fr being closed with this technique. Two patients developed complications at the access site: one patient requiring rehospitalization for intravenous antibiotics because of late access site infection, and one patient with deep venous thrombosis and pulmonary emboli. We conclude that the use of the Perclose suture-mediated closure device for closure of femoral venous access sites is feasible and should be considered especially in patients with larger venous sheaths and those at increased risk of groin complications.     

Transluminal angioplasty of the vertebral and basilar artery

Transluminal angioplasty of brachiocephalic vessels for atherosclerotic lesions is now being performed in selected cases. We have thus far treated 17 cases of vertebral artery stenosis and one case of basilar artery stenosis by intravascular balloon dilatation techniques. Clinical presenting symptoms included vertebral basilar insufficiency, repeated transient ischemic attacks (TIAs), and multiple strokes. We performed successful transluminal angioplasty in 16 patients with marked narrowing (greater than 70%) of the dominant vertebral artery from atherosclerosis. One patient with basilar artery stenosis with tandem atherosclerotic lesions was also treated by angioplasty techniques. Repeat angiography at 3- to 12-month intervals has revealed continued patency at the angioplasty site. Complications occurred in our one patient with basilar artery angioplasty, who suffered a brainstem infarction after treatment, and in one patient who had a TIA after bilateral vertebral artery angioplasty. Two other patients had residual vertebral stenosis but remained asymptomatic after the procedure. All other patients who had successful dilatation were asymptomatic at 6 months to 2 years (mean, 15 months) of follow-up. These initial studies indicate that vertebral artery angioplasty may be effective for treating high-grade atherosclerotic lesions and for improving blood flow to the posterior circulation. Angioplasty of the basilar artery is technically more difficult and has a higher degree of risk because of the many perforating branches supplying the brainstem.