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Biomedical subjects

H E James

Publications and source records attributed to H E James.

At least 19 recordsLinked to original sources
PubMed1995

Ventriculoperitoneal shunts for hydrocephalus: a focus group discussion on the selection of shunt systems in pediatrics. A report of the Pediatric Neurosurgery Research Group meeting, December 1992.

As part of the Continuing Quality Improvement Study, phase I, 12 pediatric neurosurgeons participated in a discussion group to respond to the various issues related to selection of ventriculoperitoneal shunt systems in their practice. It was estimated that between then all the 12 participants performed approximately 1200 shunt procedures per year in the USA. The data were analyzed by grid and fish-bone charts as part of the data collection. All 12 participants indicated that they preferred a reservoir in the shunt system, 8 of them indicating that they preferred this for a manual test of the system. Three indicated that they did not routinely manipulate the system for testing. One participant stated that he placed a reservoir within the shunt system primarily to prevent migration of the ventricular catheter. Nine neurosurgeons indicated that they employed cranial valves in their shunt systems, and three indicated that they employed slit-end peritoneal catheters only. In reference to Delta valves, nine participants indicated that they employed them on occasions. In reference to pressure in the valve system, one participant employed high-pressure valves at all times, five employed only medium-pressure systems, and the remaining six always employed low-pressure valves. All 12 neurosurgeons stated that the incidence of symptomatic slit ventricle in their practices was between 1% and 5%, in their mind irrespective of the system used. It was concluded that any form of ventriculoperitoneal shunt, with or without valves, with slit-end valves or cranial valves seemed to work equally well in the hands of a dedicated pediatric neurological surgeon.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebrospinal Fluid Pressure↗
PubMed1995

Cephalocele detection in utero: sonographic and clinical features.

Sonographic and clinical features of 26 fetal cephaloceles were reviewed retrospectively. The most frequent reason for referral was elevated maternal serum alpha-fetoprotein levels. The smallest lesion identified was 0.4 x 0.5 cm (frontal, at 20 weeks); the largest was 9.0 x 10.0 cm (frontal, at 27 weeks). Twenty-four of 26 cephaloceles were detected on prenatal ultrasound examination; in 13 of these, more than 50% of the intracranial contents were exteriorized. Fifteen of 24 cephaloceles detected prenatally had a sulcal pattern (identified between 16 and 36 weeks' gestation); five were solid without a sulcal pattern (identified between 13 and 21 weeks' gestation), three were cystic, and one underwent a change in appearance from solid at 21 weeks to cystic at 26 weeks. Other cranial features were evaluated and included visible skull defect, seen in 23/24 (96%), ventriculomegaly, in 6/26 (23%); microcephaly, in 12/24 (50%); beaked tectal plate, in 6/16 (38%); and flattened basiocciput, in 9/24 (38%). Of the 26 cases, 14 had normal amniotic fluid volume, five had oligohydramnios and seven had polyhydramnios. Fetuses with oligohydramnios had the highest incidence of concurrent fetal abnormalities; four of five fetuses (80%) with oligohydramnios had additional structural abnormalities. In the overall population, a very high incidence of other abnormalities was found; 17/26 (65%) cases showed additional abnormalities, some of which were not detected by ultrasound. Five fetuses had Meckel-Gruber syndrome and three had amniotic band syndrome. Only one of the 18 karyotypes obtained was abnormal (trisomy 18). Survival was very poor; only two of the eight who survived until birth are currently living.

Abnormalities, Multiple↗
PubMed1995

Postoperative chemotherapy and delayed radiation in infants and very young children with choroid plexus carcinomas. The Pediatric Oncology Group.

Eight infants with choroid plexus carcinomas were treated with surgery, prolonged postoperative chemotherapy and delayed radiation. The results suggest that some infants with choroid plexus carcinomas can be successfully treated with multimodality therapy, even allowing children with less than a gross total resection to have prolonged disease-free intervals.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Syringomyelia of the distal spinal cord in children.

The syndrome of syringomyelia in children has been extensively described in the literature and is said to most commonly involve the cervical and thoracic spinal cord. We here present two children who had an unusual constellation of signs and symptoms, characterized by bowel and bladder disturbance in one, and in the other with intermittent paroxysmal severe pain and cramping and flexion of the lower extremities accompanied at times by episodes of incontinence. Both were found on magnetic resonance imaging (MRI) to have a syrinx localized to the most distal cord. This was not associated with Arnold-Chiari malformation, trauma, tumors or any other form of spinal dysraphism. Both patients underwent placement of a syringomyelia-peritoneal shunt with complete resolution of symptomatology. Postoperative MRI revealed a complete collapse of the syringomyelia cavity. In those children presenting with bowel or bladder disturbances, associated or not with intermittent pain, flexion attacks, or cramping in the lower extremities, the differential diagnosis of a syringomyelia of the distal cord should be part of the clinical considerations.

Child, Preschool↗
PubMed1995

Human tails and associated spinal anomalies.

Human tails have been described intermittently in the literature, typically as isolated cases with varying forms of malformation. Attempts have been made to differentiate "true" tails from "tail-like" appearances. Unless identified, underlying occult spinal disorders, mass effect, and/or tethering of the spinal cord may lead to progressive neurologic damage. We report three patients with "tails" and the associated spinal anomalies.

Female↗
PubMed1994

Distal spinal cord pathology in the VATER association.

Herein the authors report the pathology of six cases of VATER association and tethered spinal cord that underwent operative intervention for removal of lipomas of the conusfilum terminale and/or release of the tethered cord. In five of the six patients, the excised filum terminale consistently showed excessive mature adipose tissue, normal blood vessels, small myelinated nerve fibers, and fibrous connective tissue. One patient had mature lobulated adipose tissue and vessels only. It is concluded that patients with the VATER association who present with distal spinal cord pathology consistently have abnormal involution of the filum terminale, the hallmark being an abnormal collection of mature fat, thickening of the filum, and extension of the fat into the conus medullaris.

Abnormalities, Multiple↗
PubMed1994

Cerebrospinal fluid shunt infection secondary to Escherichia coli bacteriuria.

A 10-year-old girl with a lumbosacral myelomeningocele, managed with clean intermittent catheterization, presented with headache, vomiting, and lethargy. The cerebrospinal fluid (CSF) and urine cultures revealed Escherichia coli, documented to be the same subtype. The organisms were subtyped and the E. coli from both the urine and CSF were noted to be of the same strain. Management consisted of intravenous antibiotics and ultimate replacement of the ventriculoperitoneal shunt. Children with myelodysplasia and CSF shunts should be carefully monitored in a multidisciplinary fashion to anticipate, correctly diagnose, and treat CSF shunt infections associated with bacteriuria.

Bacteriuria↗
PubMed1994

Impairment in shifting attention in autistic and cerebellar patients.

MRI and autopsy evidence of early maldevelopment of cerebellar vermis and hemispheres in autism raise the question of how cerebellar maldevelopment contributes to the cognitive and social deficits characteristic of autism. Compared with normal controls, autistic patients and patients with acquired cerebellar lesions were similarly impaired in a task requiring rapid and accurate shifts of attention between auditory and visual stimuli. Neurophysiologic and behavioral evidence rules out motor dysfunction as the cause of this deficit. These findings are consistent with the proposal that in autism cerebellar maldevelopment may contribute to an inability to execute rapid attention shifts, which in turn undermines social and cognitive development, and also with the proposal that the human cerebellum is involved in the coordination of rapid attention shifts in a fashion analogous to its role in the coordination of movement.

Adolescent↗
PubMed1992

Paraplegia and congenital contractures as a consequence of intrauterine trauma.

We present a newborn infant with paraplegia and contractures of the lower limbs, consistent with neurologic injury rather than malformation. The mother was involved in a severe motor vehicle accident during the sixth month of pregnancy. We propose that this infant's injuries are a result of that accident.

Accidents, Traffic↗
PubMed1992

The Vater association and spinal dysraphia.

We here present a hereto previously undescribed association of occult spinal disorders of the distal spinal cord/filum in the Vater association. We present 6 patients who were diagnosed as having the Vater association who subsequently presented with occult spinal disorders, primarily lipomas of the filum/conus complex with or without subcutaneous lipomas. Uniformly the spinal cord was tethered to the lipoma/filum complex. Progressive neurological dysfunction was noted in those in whom the diagnosis was made late in the disease. The importance of neuroimaging of the distal spinal canal, in children in whom the diagnosis of the Vater association has been made, is emphasized to prevent insidious neurological damage if not already present.

Abnormalities, Multiple↗
PubMed1992

Hydrocephalus in infancy and childhood.

Hydrocephalus is marked by the excessive accumulation of cerebrospinal fluid within the ventricles. The disorder is characterized by an imbalance in the production and reabsorption of cerebrospinal fluid. Congenital hydrocephalus is usually the result of an intrauterine infection or maldevelopment of the aqueduct of Sylvius. Acquired hydrocephalus can be caused by infection, neoplasm or hemorrhage. In infants, hydrocephalus usually presents as progressive head enlargement. The presenting symptoms in children are irritability, headache, nausea, vomiting and lethargy. Diagnosis is made with ultrasonography, computed tomography or magnetic resonance imaging. The majority of patients are treated with cerebrospinal fluid shunt procedures, most commonly the placement of ventriculoperitoneal or lumboperitoneal shunts. The outcome of hydrocephalus is determined by the etiology, the presence or absence of associated anomalies, and the timeliness of diagnosis and treatment.

Cerebrospinal Fluid Shunts↗
PubMed1990

Prenatal diagnosis of a craniopharyngioma using ultrasonography and magnetic resonance imaging.

We report an infant with a craniopharyngioma which was detected in utero. Maternal uterine ultrasonography, done at 27 weeks because of polyhydramnios, revealed a 4 cm midline mass near the base of the fetal skull. At 31 weeks, magnetic resonance imaging of the maternal abdomen confirmed the presence of a mass in the region of the third ventricle and revealed hydrocephalus. Two days post-partum a computed tomography (CT)-guided needle biopsy of the mass was performed and recovered tissue which was histologically consistent with a craniopharyngioma. The infant's postnatal period was complicated by seizures, which were treated with phenobarbital, and by progressive hydrocephalus, necessitating placement of a ventriculo-peritoneal shunt. He also received therapy for central hypothyroidism and diabetes insipidus. The infant's parents refused permission for attempted resection of the tumour and he died at 8 weeks of age. This represents the second reported case of an antenatally detected craniopharyngioma. Four other cases of different intracranial tumours have been detected in utero using ultrasound, with no reported survivors past 3 days of age. There is a uniformly poor prognosis of such infants, but earlier diagnosis and intervention may change this result.

Craniopharyngioma↗
PubMed1990

Cryogenic brain oedema: loss of cerebrovascular autoregulation as a cause of intracranial hypertension. Implications for treatment.

Experimental cryogenic brain oedema was created in albino rabbits, and intracranial pressure (ICP), cerebral blood flow (CBF), EEG, blood pressure, central venous pressure, were subsequently studied at a constant PaCO2. Upon completion the brain water content of the gray and white matter was analyzed by gravimetry. The findings were compared to controls and sham-operated. Two subsets of elevated ICP following cryogenic injury were identified: one with a mean of 6.2 +/- 3.3 torr (n = 7) and the other of 19.3 +/- 9 (n = 5) (p less than 0.005). Both these subsets had similar white and gray matter gravimetry values indicating that the magnitude of cerebral oedema was comparable and could not explain the difference in ICP. There was however a significant difference in the CBF of the left hemisphere between these subsets, with Subset A at 49.1 +/- 9 ml/100 g/min and Subset B with 70 +/- 9.1 (p less than 0.001). We conclude that the ICP elevation in the cryogenic oedema model may be due to not only increased brain water of the injured hemisphere, but also to increased cerebral blood volume due to increased CBF.

Animals↗
PubMed1989

The reaction specificities of the thylakoidal processing peptidase and Escherichia coli leader peptidase are identical.

Proteins which are transported across the bacterial plasma membrane, endoplasmic reticulum and thylakoid membrane are usually synthesized as larger precursors containing amino-terminal targeting signals. Removal of the signals is carried out by specific, membrane-bound processing peptidases. In this report we show that the reaction specificities of these three peptidases are essentially identical. Precursors of two higher plant thylakoid lumen proteins are efficiently processed by purified Escherichia coli leader peptidase. Processing of one precursor, that of the 23 kd photosystem II protein, by both the thylakoidal and E. coli enzymes generates the correct mature amino terminus. Similarly, leader (signal) peptides of both eukaryotic and prokaryotic origin are cleaved by partially purified thylakoidal processing peptidase. No evidence of incorrect processing was obtained. Both leader peptidase and thylakoidal peptidase are inhibited by a synthetic leader peptide.

Amino Acid Sequence↗
PubMed1989

Transport of proteins into chloroplasts. Import and maturation of precursors to the 33-, 23-, and 16-kDa proteins of the photosynthetic oxygen-evolving complex.

The 33-, 23-, and 16-kDa proteins of the photosynthetic oxygen-evolving complex are synthesized as precursors in the cytoplasm and transported into the thylakoid lumen of higher plant chloroplasts. In this report we have analyzed the import and maturation of these precursors, using reconstituted protein import assays and partially purified preparations of the processing peptidases involved. Precursors of the 33- and 23-kDa proteins from Spinacia and Triticum aestivum are processed by a stromal peptidase to intermediate forms; polypeptides of similar size are observed during the transport of these precursors and possibly that of the 16-kDa protein, into isolated chloroplasts. Complete maturation of the 33- and 23-kDa proteins is carried out by a thylakoidal peptidase shown previously to be involved in plastocyanin biogenesis. The data support an import mechanism involving successive cleavages by the stromal and thylakoidal processing peptidases.

Chlorophyll↗
PubMed1989

Migraine headaches in hydrocephalic children: a diagnostic dilemma.

Headaches, vomiting, and altered sensorium can be seen in patients with shunt malfunction as well as in those with migraines. We report five cases in which children with hydrocephalus and CSF shunts presented with a variety of recurring symptoms, including headache, vomiting, impairment of consciousness to the point of coma, and, in one patient, decerebrate posturing. Various diagnoses were entertained: shunt malfunction, slit ventricle syndrome, and low pressure (overshunting). Repeated procedures were carried out in all patients, including shunt taps, multiple shunt revisions, and a subtemporal decompression. When the diagnosis of migraine was considered, four patients improved on propranolol therapy; one failed this therapy but responded to verapamil. We conclude that in patients with hydrocephalus and repeated bouts of symptoms such as headaches, vomiting, and impairment of consciousness and in the case of documented, adequate shunt function, the diagnosis of migraine be entertained before further operative intervention is undertaken.

Cerebrospinal Fluid Shunts↗