Search PubMed⌕ Search

Biomedical subjects

M S Edwards

Publications and source records attributed to M S Edwards.

At least 127 records · Page 7Linked to original sources
PubMed1991

Intracranial arachnoid cysts in children. A comparison of the effects of fenestration and shunting.

The best operative intervention for children with arachnoid cysts remains the subject of controversy. Recent reports stress that craniotomy for cyst fenestration is associated with a low incidence of morbidity and mortality and may leave the child shunt-independent. The cases of 40 pediatric patients with arachnoid cysts treated between 1978 and 1989 are reported. Five children with mild symptoms and small cysts that remained stable on follow-up studies have not required surgical intervention. Of 15 patients with cysts initially treated by fenestration, 10 (67%) showed no clinical or radiographic improvement postoperatively and have undergone cyst-peritoneal (eight patients) or ventriculoperitoneal (VP) shunting (one patient), or revision of a VP shunt placed for hydrocephalus before cyst fenestration (one patient). Two other patients with existing VP shunts required no further procedures. Thus, only three (20%) of 15 patients initially treated by fenestration remain shunt-independent after a median follow-up period of 8 years. The 20 other patients were initially treated by cysts shunting and all improved postoperatively; shunt revision has been necessary in six (30%) of these 20 patients because of cysts recurrence. Cyst location influenced the success of shunt treatment; none of the seven middle cranial fossa cysts treated by shunting have required revision, but results with cysts in other locations were less favorable. In all locations, though, shunting was more successful than fenestration. It is concluded that cyst-peritoneal or cyst-VP shunting is the procedure of choice for arachnoid cysts in most locations, including those in the middle cranial fossa.

Arachnoid↗
PubMed1991

Management of chiasmal and hypothalamic gliomas of infancy and childhood with chemotherapy.

Between March, 1983, and February, 1989, 19 infants or children with chiasmal/hypothalamic gliomas were treated with chemotherapy after either surgical or radiological diagnosis. The patients ranged in age from 15 weeks to 15.6 years (median 3.2 years) at the start of therapy. Twelve patients were treated immediately after diagnosis because of progressive symptoms, and seven received chemotherapy after either radiographic progression or clinical deterioration, including progressive visual loss or intracranial hypertension. Based on biopsy results, seven of these tumors were classified as juvenile pilocytic astrocytomas, two as astrocytomas, two as highly anaplastic astrocytomas, and one as a subependymal giant-cell astrocytoma. There was associated neurofibromatosis in four patients. The two initial patients were treated with either actinomycin D and vincristine or 5-fluorouracil, hydroxyurea, and 6-thioguanine. The remaining patients received nitrosourea-based therapy; 15 evaluable patients were treated with a five-drug regimen that included 6-thioguanine, procarbazine, dibromodulcitol, 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), and vincristine and one received 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and 5-fluorouracil. Fifteen of the 18 evaluable patients initially managed with chemotherapy either responded to therapy or their condition stabilized. Median time to tumor progression has not been reached at a median follow-up period of 79 weeks (range 6.6 to 303 weeks), and no tumor-related death has occurred with a median follow-up period of 79 weeks (range 18 to 322 weeks) from the initiation of therapy. The four patients who failed therapy or whose disease progressed after chemotherapy were treated satisfactorily with radiation therapy. Initial improvement or stabilization of visual function was obtained in 16 patients. Endocrine function remained stable in all patients during treatment, although three patients required pharmacological treatment for endocrinopathy that was present at diagnosis. These preliminary results suggest that nitrosourea-based cytotoxic regimens are useful for the initial treatment of children with chiasmal/hypothalamic gliomas, and allow potentially harmful radiation therapy to be deferred until progression of disease.

Adolescent↗
PubMed1991

Metastatic juvenile pilocytic astrocytoma. Case report.

The authors report the case of a metastatic juvenile pilocytic astrocytoma of the hypothalamic region in a 10-year-old boy. Eight years after craniotomy and radiation therapy, the tumor spread via cerebrospinal fluid pathways to the left cerebellar tonsil and the lumbosacral region. Histological evaluation of both the original hypothalamic and the new lumbosacral masses showed features of a slow-growing juvenile pilocytic astrocytoma with no evidence of malignant transformation. The clinical implications and possible mechanisms of metastatic spread are discussed.

Astrocytoma↗
PubMed1991

Body weight and longevity in genetically obese and non-obese mice fed fat-modified diets.

Polygenically obese and genetically related non-obese male mice were fed ad libitum purified diets differing in quantity or type of fat from weaning onward to determine effects upon weight gain and life span. Non-obese mice lived 71% longer than mice in the obese line (mean = 753 d versus 441 d). Obese mice fed a low-fat diet containing 1% corn oil by weight lived 26% longer than their obese counterparts fed high fat diets containing 20% additional fat as either corn oil or beef tallow. The low fat diet had more of a normalizing effect upon longevity than upon body weight in polygenically obese mice. Conversely, dietary fat concentration had little effect upon longevity in non-obese mice and more effect upon body weight than in genetically obese mice. Type of dietary fat had little effect upon body weight and no effect upon longevity. The results of this study suggest that life span was only partially explained by body weight, and furthermore, that genetics play a greater role than body weight or dietary fat concentration in determining life span.

Animals↗
PubMed1990

Recurrent meningitis and Mondini dysplasia.

Three infants with cerebrospinal fluid otorrhea and recurrent meningitis due to Mondini dysplasia have been treated at Baylor College of Medicine, Houston, Tex; 39 other patients with this association have been described. This review highlights the characteristics and embryologic basis of the malformation. The clinical evaluation of an infant with recurrent meningitis is outlined, and the importance of brain-stem response audiometry and thin-cut computed tomography of the temporal bones is discussed. Surgical management depends on the functional status of the dysplastic ear; usually, a stapedectomy is performed and the vestibule is obliterated. Although the surgical failure rate is 30% after one procedure, early identification of the dysplasia and prompt surgical management diminish morbidity and mortality and permit early habilitation of the child with congenital hearing impairment.

Audiometry, Evoked Response↗
PubMed1990

Deletion mapping of the medulloblastoma locus on chromosome 17p.

Isochromosome 17q has previously been observed consistently in cytogenetic studies of medulloblastoma, the most common posterior fossa neoplasm in children. We performed a restriction fragment length polymorphism (RFLP) investigation of medulloblastoma which showed a loss of chromosome 17p sequences in 45% of these tumors. This finding was predictive of a poor clinical response to treatment. A contiguous panel of markers permitted mapping of the deletion to 17p12-p13.1, the same chromosomal region for which loss of alleles has been shown in tumor specimens from patients with colon cancer, and the same region to which the p53 gene has been mapped. This suggests that medulloblastoma is associated with a recessive oncogene on chromosome 17p that may be involved in the genesis of several embryologically unrelated neoplasms and that the absence of this gene in tumor tissue has prognostic significance.

Brain Neoplasms↗
PubMed1990

Bladder function in patients with lipomyelomeningocele.

We evaluated preoperative and postoperative bladder function in 31 consecutive patients who underwent definitive operative correction of lipomyelomeningocele. Of 12 patients less than 1.5 years old at operation, bladder function was normal preoperatively and postoperatively in 5 (42%) and normalized postoperatively in 4 (33%). In 5 patients (42%) abnormal urodynamic findings were the only sign of neurological abnormality. Of the 19 patients older than 1.5 years at operation bladder function was normal preoperatively and postoperatively in only 4 (21%), and normalized postoperatively in none. We conclude that the majority of patients with lipomyelomeningocele have bladder dysfunction, and that in some cases this dysfunction can be prevented and/or reversed by early neurosurgical intervention. Urodynamic assessment is helpful as part of the neurological evaluation and in directing patient care.

Adolescent↗
PubMed1990

Patterns of immune response among survivors of group B streptococcal meningitis.

Serum samples from 10 infants surviving type III, group B streptococcal (GBS) meningitis were collected acutely and longitudinally for 6 months to determine patterns of antibody response to the capsular polysaccharide and their in vitro functional correlates. Five infants who failed to develop specific antibody at a mean of 3.8 weeks after diagnosis had an increase of greater than or equal to 1.0 microgram/ml after another 4-8 weeks. This IgM-predominant type-specific antibody declined to baseline 2-4 months later. Opsonophagocytosis of type III GBS increased from 0 to 88% in parallel with peak antibody response. Three infants developed increased antibody and opsonophagocytosis at 15-31 weeks after diagnosis, while two had no detectable response. Despite increasing complement levels, opsonophagocytosis of type III GBS was poor with low specific antibody levels These results suggest that survivors of GBS meningitis transiently develop specific antibody and associated efficient opsonophagocytosis, but functional competence does not persist despite maturation to adult levels of complement proteins.

Aging↗
PubMed1990

Role of complement receptors in opsonophagocytosis of group B streptococci by adult and neonatal neutrophils.

The role of complement receptors in bactericidal activity for types III and Ia group B streptococci (GBS) by adult or neonatal polymorphonuclear leukocytes (PMNL) was explored using polyclonal and monoclonal antibodies to complement receptors one (CR1) and three (CR3). In an opsonophagocytic assay, selective blockade of the CR3 sugar or lectin-like binding site on adult or neonatal PMNL effected a significant reduction in killing of both GBS serotypes that was more pronounced for type III. In contrast, blockade of the iC3b binding site effected greater inhibition of bactericidal activity for type Ia than for type III GBS. When both the CR3 sugar or lectin-like binding site and CR1 were blocked, inhibition was enhanced for type Ia GBS by adult PMNL and for both serotypes by neonatal PMNL. These results demonstrate a role for both CR1 and CR3 in the opsonophagocytosis of GBS. Possibly, differences in CR3 epitope utilization contribute to the differential virulence among GBS serotypes in neonates.

Adult↗
PubMed1990

Histologic evaluation of the coronal sutures in trigonocephaly.

Thirteen cases of trigonocephaly, seven isolated and six syndromic cases, were evaluated by preoperative neurologic and genetic evaluation and by radiographic evaluation (CT scans). All 13 were treated in an identical surgical manner. Specimens from the coronal sutures were obtained during surgery for histologic evaluation. All of the isolated cases, except one, showed normal coronal sutures and had a good-to-excellent result from surgery. All of the syndromic or secondary cases showed an abnormality of the coronal sutures. Four of the six cases had bad results; two required subsequent surgical procedures. It is our opinion that if a coronal suture abnormality is noted on preoperative CT scans or if preoperative evaluation demonstrates an associated syndrome or CNS malformation, the results from surgery must be guarded.

Cranial Sutures↗
PubMed1990

Intracerebral arteriovenous fistulas associated with intraparenchymal varix in childhood: case reports.

This report describes three children, each of whom developed an unusual malformation consisting of one or more intracerebral arteriovenous fistulas and a large intraparenchymal venous varix. Their clinical symptoms were similar to those produced by aneurysms of the vein of Galen: increasing head circumference, seizures, hemorrhage, and developmental delay. We treated each child with endovascular embolization and/or surgery and obtained complete closure of all fistulas without mortality.

Arteriovenous Fistula↗
PubMed1990

Management of hypothalamic gliomas in children: an analysis of 33 cases.

The cases of 33 children with hypothalamic-chiasmatic gliomas are reviewed. Radiation therapy produced clinical or radiographic improvement in 11 (46%) of 24 patients. Progression was documented in 18 patients (54%). Overall, the median time to tumor progression was 60 months; it was 70 months in patients who received radiation therapy and 30 months in those who did not (P less than 0.05). Chemotherapy, either given initially or at the time of progression, caused the tumor to respond or to stabilize in 10 patients. Partial resection of the tumor led to improvement in 3 of 12 patients, obviating the need for a shunt in 2 of them; there were no deaths and postoperative morbidity was transient and minimal (diabetes insipidus, intraventricular hemorrhage, and left hemiparesis in one patient each). The 5- and 10-year survival probabilities were 93 and 74%, respectively. Patients with neurofibromatosis had a better prognosis.

Adolescent↗
PubMed1990

Interventional neuroradiological management of vein of Galen malformations in the neonate.

Since 1978, the authors have seen 14 neonates with vein of Galen malformations who were born with severe congestive heart failure. The 5 infants treated before 1983 underwent craniotomy and clipping of feeding vessels; all died in the perioperative period. Since 1983, 8 neonates have been treated with combined arterial and venous interventional neuroradiological techniques; 6 infants survived. Two-dimensional echocardiography, color Doppler flow imaging, and pulsed Doppler ultrasound were used to assess blood flow within the malformation before and after staged transluminal embolic procedures were performed. The results of the diagnostic studies and the clinical status of the infants were used to evaluate the success of embolic therapy and the need for further neuroradiological intervention.

Cerebral Veins↗
PubMed1990

Serial ultrasonographic evaluation of neonatal vein of Galen malformations to assess the efficacy of interventional neuroradiological procedures.

Two-dimensional echocardiography complemented with color-flow imaging and pulsed Doppler ultrasound was used to evaluate one fetus and five neonates with a vein of Galen malformation who had severe high-output congestive heart failure and cranial bruits at birth. Intracranial blood flow through the vein of Galen malformations, cardiac status, and direction of aortic blood flow were assessed before and after staged interventional neuroradiological treatment with transarterial and transvenous embolization procedures. Color-flow imaging in each infant displayed the major vascular anatomy including feeding vessels and the patterns of filling of the vein of Galen malformations. Pulsed Doppler ultrasound performed on the descending aorta above the diaphragm showed the degree of diastolic flow reversal indicative of runoff into the vein of Galen malformations. A reduction in blood flow through the vein of Galen malformation was seen on color-flow imaging in four patients treated successfully by embolic procedures. The ratio of diastolic retrograde flow velocity in the descending aorta to systolic antegrade velocity decreased from 0.51 +/- 0.15 (mean +/- standard deviation) to 0.15 +/- 0.20 (P less than 0.05). Color-flow imaging and pulsed Doppler ultrasonography provided anatomical and pathophysiological information regarding cardiac hemodynamics and intracranial blood flow; with the patient's clinical status, these methods provided a reliable, noninvasive means to evaluate the effectiveness of therapy and the need for further treatment in neonates with vein of Galen malformations.

Cerebral Veins↗
PubMed1990

Antimigraine treatment for slit ventricle syndrome.

Slit ventricle syndrome is characterized by chronic or recurring headaches associated with subnormal ventricular volume in patients who have undergone shunt treatment for hydrocephalus. There appear to be at least three pathophysiological mechanisms that cause this syndrome: 1) intermittent shunt malfunction; 2) intracranial hypotension; and 3) paroxysms of increased intracranial pressure in the presence of normal shunt function. To treat seven patients with slit ventricle syndrome caused by paroxysms of elevated intracranial pressure, we successfully used antimigraine therapy rather than standard calvarial expansion procedures. None of these patients has required shunt revision or calvarial expansion during a mean follow-up period of 2 years. The symptoms of slit ventricle syndrome may be a form of "acquired" migraine in shunt patients. We suggest that, in clinically stable patients with normal shunt function, treatment against migraine may stabilize symptoms resulting from paroxysms of increased intracranial pressure. Such treatment may prevent unnecessary shunt revisions and/or calvarial expansion procedures.

Adult↗