Development of lumbar spinal cord and cortical evoked potentials after tibial nerve stimulation in the pre-term newborns: effects of gestational age and other factors.

Pre-term neonates are at increased risk for neurological dysfunction. Several investigators have found scalp recorded somatosensory evoked potential studies (SSEPs) after median nerve stimulation useful in the evaluation of newborn infants with asphyxiation and the effects of other adverse prenatal and perinatal factors. In order to evaluate the entire developing neuraxis, we undertook SSEPs after tibial nerve stimulation (PTN-SSEP) in pre-term neonates.

Formation of a functional ribosome-membrane junction during translocation requires the participation of a GTP-binding protein.

The requirement for ribonucleotides and ribonucleotide hydrolysis was examined at several distinct points during translocation of a secretory protein across the endoplasmic reticulum. We monitored binding of in vitro-assembled polysomes to microsomal membranes after removal of ATP and GTP. Ribonucleotides were not required for the initial low salt-insensitive attachment of the ribosome to the membrane.

Effect of sleep position on sleep apnea and parafunctional activity.

Parafunctional activity (toothgrinding, toothclenching and bruxism) is a common problem which may lead to masticatory muscle and temporomandibular joint pain, and may result from sleep arousal or disturbances. Sleep apnea is another common sleep disorder which results in disrupted sleep architecture and frequent arousals. Because sleep apnea leads to sleep arousals, and because sleep arousals are thought to result in increased parafunctional activity, we undertook the present study to determine the relationship between sleep apnea and parafunctional activity.

Evaluation of children and young adults with tethered spinal cord syndrome. Utility of spinal and scalp recorded somatosensory evoked potentials.

The diagnosis of tethered spinal cord syndrome should be considered in young patients with progressive orthopedic deformities, lower extremity weakness, urinary and fecal incontinence, low back pain, or combinations of these symptoms. Myelographic, computed tomographic, and urodynamic studies are useful for establishing a diagnosis, but contribute little to the evaluation of lower extremity sensory function or to the assessment of electrophysiologic impairment of the spinal cord itself. To determine the diagnostic usefulness of the somatosensory evoked potential after posterior tibial nerve stimulation (posterior tibial nerve somatosensory evoked potential) in tethered spinal cord syndrome, 22 consecutive patients with symptoms of tethered spinal cord syndrome (aged 18 months to 22 years) underwent recording of posterior tibial nerve somatosensory evoked potential; results were correlated with clinical, myelographic, and operative findings.

Ultrastructural evidence in rabbit ear arteries that barium enters smooth muscle cells through calcium channels.

The calcium channel blocker methoxyverapamil, at 10(-5) mol/l, abolished contractile responses of isolated perfused rabbit ear arteries to barium. Entry of barium into smooth muscle cells was detected by the presence of mitochondrial granules specific for barium. Methoxyverapamil (10(-5) mol/l) prevented the appearance of barium granules.

Translational control of insulin biosynthesis. Evidence for regulation of elongation, initiation and signal-recognition-particle-mediated translational arrest by glucose.

The biosynthesis of insulin in the islets of Langerhans is strongly controlled at the translational level by glucose. We have used a variety of experimental approaches in efforts to dissect the mechanisms underlying the stimulatory effect of glucose. To assess its effects on rates of peptide-chain elongation, isolated rat islets were labelled with [3H]leucine at different glucose concentrations in the presence or absence of low concentrations of cycloheximide.

Neonatal paralytic poliomyelitis. A case report.

Neonatal poliomyelitis, which was rare even when poliomyelitis was widespread, has not been reported in the United States since use of live oral poliovirus vaccine (Sabin's vaccine) became widespread. We report a child who became symptomatic with apnea at 18 days of age and who subsequently developed a permanent monoparesis. Serologic and cultural evidence indicated the virus as poliovirus vaccine type.

Purification of microsomal signal peptidase as a complex.

We report here the purification to near homogeneity of signal peptidase from canine pancreatic microsomes. Purification was monitored using an improved post-translational assay. A 42-fold enrichment over starting membranes was achieved by selective solubilization in nonionic detergent/high-salt buffer followed by gradient sievorptive anion and cation exchange chromatography, hydroxylapatite chromatography, gel filtration, and sucrose gradient velocity sedimentation.

Prenatal screening for risk of major parenting problems: further results from the Queen Mary Maternity Hospital Child Care Unit.

This research revealed in Stage I the ability to identify during the prenatal period women at risk for possible child abuse and in Stage II an intervention program which when introduced resulted in fewer high-risk mothers relinquishing the care of their infants. The research had two main aims: to use the data from Stages I and II to reassess the criteria for identifying "at risk" mothers, and to develop a brief, easily administered screening questionnaire which could be standardized for widespread prenatal use; and to collect data on a random sample of prenatal patients, to use these data for confirming the validity and stability of the screening procedures, and to estimate the incidence of potentially high-risk mothers in an urban population.

Verapamil-induced changes in central conduction in patients with multiple sclerosis.

The electrophysiological characteristics of demyelinated axons are sensitive to changes in plasma calcium concentration. This study investigated the effect of verapamil, a calcium antagonist drug, on brainstem auditory, visual, and somatosensory evoked potentials in multiple sclerosis patients. Eight clinically stable patients with abnormal visual and/or brainstem auditory evoked potentials and four normal volunteers were studied.

Translocation of secretory proteins across the microsomal membrane occurs through an environment accessible to aqueous perturbants.

We have characterized the association of a nascent secretory protein with the microsomal membrane at two distinct stages in cell-free synthesis and translocation. Stage one corresponded to a nascent chain of approximately 70 residues generated via elongation arrest by the signal recognition particle (SRP). Binding to microsomal membranes occurred independently of chain elongation and required SRP receptor.

Effects of clinical infrared laser on superficial radial nerve conduction.

The purposes of this study were to demonstrate the effects of infrared laser radiation on the sensory nerve conduction of a specified peripheral nerve in man and determine temperature changes in the tissue surrounding the treated nerve. Twenty healthy adults were divided into three groups: control (n = 5); experimental (n = 10), infrared laser radiation at 20 sec/cm2; and experimental (n = 5), infrared laser radiation treatment at 120 sec/cm2. Antidromic sensory nerve conduction studies were performed on the superficial radial nerve of each subject's right forearm.

Developmental assessment of spinal cord and cortical evoked potentials after tibial nerve stimulation: effects of age and stature on normative data during childhood.

Somesthetic information from lower extremities is processed by cerebral cortex after traversing the sensory pathways of peripheral nerve, spinal cord, brain-stem and thalamus. Clinical utility of somatosensory evoked potentials (SSEPs) during human development requires systematic analysis of normative data acquired during various stages of body growth and nervous system maturation. Accordingly, SSEPs after tibial nerve stimulation were studied in 32 normal awake children (1-8 years old) and compared with values obtained in young adults (18-40 years old).

Mitochondrial granules: are they reliable markers for heavy metal cations?

Mitochondrial granules have been used as markers for heavy metal cations, but since such granules can also be found in tissues in the absence of such cations, an attempt was made to define conditions under which these different granules might be visualised. The tissue used was the smooth muscle of the central ear artery of the rabbit. In all studies, the presence or absence of mitochondrial granules was determined by several observers, using coded specimens so that the previous treatment of the specimens was not at the time known to the observers.

Brain biopsy in cases of neonatal herpes simplex encephalitis.

Neonatal herpes simplex encephalitis (HSE) can represent a difficult diagnostic problem when it occurs without concomitant mucocutaneus lesions and usually requires brain biopsy for diagnosis. Asymptomatic for the initial 2 to 4 weeks of life, the three infants we describe with localized HSE came to medical attention only because they developed persistent seizures and other nonspecific symptoms. Lumbar spinal fluid obtained from these children at clinical presentation showed an encephalitic pattern.

Features of the geriatric EEG: age-dependent incidence of POSTS.

Positive occipital sharp transients of sleep (POSTS) are well recognized as a normal electroencephalographic phenomenon in young to middle-aged persons, but little comment has been made concerning their occurrence in geriatric age groups. This study encompassing 365 electroencephalograms, showing POSTS among patients aged 22 to 86 years, demonstrates that the presence of POSTS is not an age limited occurrence, but extends over a wide age range into the later decades of life. Though the incidence of POSTS declined with advancing age, the diminution was not striking until after age 70.