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Biomedical subjects

H E James

Publications and source records attributed to H E James.

At least 37 records · Page 2Linked to original sources
PubMed1993

Emergency management of acute coma in children.

A deteriorating neurologic state in a child with an acute brain insult is a life-threatening situation, and the decisions made during the first few minutes of management will frequently determine the outcome. Often, the family physician is the first person contacted by the parents to evaluate the sudden change in a child. Attention must be first directed toward ensuring an airway and maintaining adequate circulation. Computed tomographic study, toxicology screen and determination of acid-base status should follow. Possible causes of acute coma in children include trauma, child abuse, intracerebral hemorrhage, tumor, meningitis and poisoning.

Acute Disease↗
PubMed1993

Postoperative chemotherapy and delayed radiation in children less than three years of age with malignant brain tumors.

BACKGROUND: Among patients with malignant brain tumors, infants and very young children have the worst prognosis and the most severe treatment-related neurotoxic effects. Therefore, in 1986, the Pediatric Oncology Group began a study in which postoperative chemotherapy was given in order to permit a delay in the delivery of radiation to the developing brain. METHODS: Children under 36 months of age with biopsy-proved malignant brain tumors were treated postoperatively with two 28-day cycles of cyclophosphamide plus vincristine, followed by one 28-day cycle of cisplatin plus etoposide. This sequence was repeated until the disease progressed or for two years in 132 children 24 months of age at diagnosis and for one year in 66 children 24 to 36 months of age at diagnosis. After this, the patients received radiation therapy. The response to the first two cycles of chemotherapy was measured in 102 patients with residual postoperative disease. RESULTS: The first two cycles of cyclophosphamide and vincristine produced complete or partial responses in 39 percent of the 102 patients who could be evaluated. The response rates were highest among patients with medulloblastomas, malignant gliomas, or ependymomas. Patients with brain-stem gliomas or embryonal tumors (primitive neuroectodermal tumors) had little or no response. The progression-free survival rate was 41 percent at one year for children who were 24 to 36 months old at diagnosis and 39 percent at two years for those under 24 months of age at diagnosis. Multivariate analysis identified embryonal tumors as a significant adverse prognostic feature (relative risk, 2.2; 95 percent confidence interval, 1.4 to 3.4) and complete resection as a favorable feature (relative risk, 0.33; 95 percent confidence interval, 0.20 to 0.54). Complete responses to chemotherapy were associated with a progression-free survival rate approaching that achieved with gross total resection. A comparison of cognitive evaluations obtained at base line and after one year of chemotherapy revealed no evidence of deterioration in cognitive function. CONCLUSIONS: Chemotherapy appears to be an effective primary postoperative treatment for many malignant brain tumors in young children. Disease control for one or two years in a large minority of patients permitted a delay in the delivery of radiation and, on the basis of preliminary results, a reduction in neurotoxicity. For patients who had undergone total surgical resection or who had a complete response to chemotherapy, the results are sufficiently encouraging to suggest that radiation therapy may not be needed in this subgroup of children after at least one year of chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Effects of acute isotonic saline administration on serum osmolality, serum electrolytes, brain water content and intracranial pressure.

Albino rabbits who had undergone a cryogenic insult over the left parieto-occipital cortex 24 hours previously were analyzed for serum osmolality, serum electrolytes, brain water content, intracranial pressure (ICP), following a 3 hour baseline intravenous infusion of above maintenance isotonic saline, and compared to sham operated controls. In the acute setting there was no difference in the serum osmolality and electrolytes between the subgroups. There was a significant increase in the water content of the white matter of the left hemisphere in the cold lesion group when compared to sham operated controls. Despite the intravenous fluid challenge, the ICP did not rise during the 3 hour experimental trial when compared to pre-trial values. It is concluded that in the acute setting an isotonic fluid load is compensated without significant disturbances of the above measured parameters, and should not alter therefore intracranial dynamics per se, in acute resuscitation measures following brain insults.

Animals↗
PubMed1993

The third dimension in pediatric neurosurgery. A preliminary report.

Three-dimensional computerized imaging with current advanced software (Cemax) has resulted in superior visual ergonomics and rapid data acquisition utilizing standard computed tomography (CT) or magnetic resonance imaging. Consequently, within 15-20 min of a standard CT scan, the information is available to be employed for operative planning, allowing this useful tool to be practical in emergency situations, such as trauma. The advanced lifelike imaging permits excellent preoperative planning due to correct demonstration of the surgical anatomy. We present three patients to illustrate the applications of this technology: one with a skull base tumor, another with a complex ethmoidal encephalocele, and a third with severe craniofacial trauma. We have found this technique to have a significant impact on the management of pediatric neurosurgery patients with complex pathology.

Arachnoid Cysts↗
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↗
PubMed1988

Sudden infant apnea and insidious hydrocephalus.

Hydrocephalus secondary to intracranial-intraventricular hemorrhage is a common complication in the clinical course of the high-risk preterm newborn. Hydrocephalus in this population may be insidious without obvious intracranial hypertension. Apnea and respiratory arrest continue to cause concern following nursery discharge of the high-risk preterm newborn. We report a child who presented to the neonatology service with episodes compatible with serious sudden cardiorespiratory arrest. Insidious "non-hypertensive" hydrocephalus was documented as being responsible for these episodes, which resolved with treatment of the hydrocephalus. The perinatal neurosurgical consultant should be aware of this syndrome and instruct the parents and the pediatricians of these infants, who at the time of discharge are asymptomatic but have ventricular enlargement on neuro-imaging studies. The information presented here is of current importance, since most neonatologists are unaware of the syndrome of insidious hydrocephalus.

Apnea↗
PubMed1987

Severe intracranial hemorrhage and hydrocephalus in low-birthweight infants treated with CSF shunts.

The high-risk low-birth-weight newborn not uncommonly develops intracranial hemorrhage and intraventricular hemorrhage (ICH/IVH) from the immature state of the germinal matrix. Posthemorrhagic hydrocephalus may develop. Infants with small hemorrhages (grades I, II of Papile), with or without hydrocephalus have been shown to develop normally in 80%-90% of cases. There is limited information in the literature about the management and outcome of infants with more severe hemorrhages (grades III, IV of Papile), due to the dismal outlook as to their outcome in most centers. The current status and concerns as to the management of these infants is reviewed, and the aspects of neurosurgical and neonatal follow-up and outcome are described. A significant number of these infants have severe handicaps, which are primarily motor. However, a group of infants is noted who have normal intellectual performance despite varying degrees of motor handicaps: 18% have normal intellectual and motor development. In the current series predictors of poorest outcome are the presence of grade IV hemorrhage and/or seizures. The vast majority of the grades III and IV hemorrhages develop hydrocephalus that is a complex management issue for the neurosurgeon.

Acute Disease↗
PubMed1987

Insidious hydrocephalus in the preterm newborn following discharge from the nursery.

Posthemorrhagic ventriculomegaly may be due to perinatal brain damage and consequent cerebral atrophy, or represent progressive hydrocephalus due to impairment of CSF flow and reabsorption. 'Arrested' hydrocephalus occurs when the CSF pathways are adequate and, hence, intracranial hypertension no longer exists. The differential diagnosis is often difficult and insidious progressive hydrocephalus should always be a concern in the high-risk preterm newborn. We report 10 preterm infants who were discharged with the diagnosis of arrested hydrocephalus (7) or cerebral atrophy (3), and who later developed progressive severe hydrocephalus 1.5-15 months after the discharge. Five had been treated with intermittent lumbar punctures, while 4 had not received any treatment prior to nursery discharge. One infant died prior to the shunt procedure. Progressive insidious hydrocephalus should be suspected in preterm infants with intracranial hemorrhage following discharge from the nursery.

Cerebral Ventricles↗