Search PubMed⌕ Search

Biomedical subjects

R M Scott

Publications and source records attributed to R M Scott.

At least 109 records · Page 6Linked to original sources
PubMed1991

The change in patterns of relapse in medulloblastoma.

The authors reviewed 89 patients treated for cerebellar medulloblastoma between 1970 and 1989 to determine the impact of changing treatment (high-dose posterior fossa radiation therapy and chemotherapy) on the pattern of failure in medulloblastoma. Between 1970 and 1983, 50 patients (median follow-up, 110 months) were treated with surgery and postoperative craniospinal irradiation (CSI). Nineteen of the 50 (38%) recurred in the central nervous system (CNS). Isolated systemic (bone) metastases occurred in six. The median time to the development of bone metastases was 12 months. Since 1984, 39 patients (median follow-up, 27 months) were treated with preradiation chemotherapy consisting of cisplatin and vincristine for 9 weeks before initiation of CSI. Nine of the 39 (23%) patients recurred in the CNS. There were no systemic failures in this cohort. The actuarial 5-year disease-free survival was 55 +/- 7% for the earlier cohort and 72 +/- 8% for the later cohort (P equals 0.3). Posterior fossa recurrence was associated with radiation therapy to this area. The cumulative incidence of posterior fossa relapse was 50 +/- 13% in patients who received less than 5300 cGy and 18 +/- 7% in those who received 5300 cGy or more (P equals 0.005). All six bone relapses were in patients treated with CSI alone and 5300 cGy or more to the posterior fossa for a 5-year cumulative incidence of bone metastases of 18 +/- 7% compared with 0% for patients treated with 5300 cGy or more and chemotherapy (P equals 0.03). The authors concluded that high-dose radiation therapy has altered the pattern of relapse with an increase in systemic recurrence after radiation therapy alone that is now equivalent to the risk of recurrence in the posterior fossa. Chemotherapy may be indicated in an attempt to decrease this high risk of systemic metastases.

Adolescent↗
PubMed1991

The prognostic significance of postoperative residual tumor in ependymoma.

Between 1970 and 1989, 29 patients with intracranial ependymomas were evaluated and treated at the Children's Hospital in Boston. With a median follow-up of 82 months, the actuarial survival rates at 5 and 10 years were 61 +/- 10% and 46 +/- 12%, respectively. Anaplastic histological findings were uncommon (2 of 29). Initial postoperative radiotherapy was given to 25 patients, with a median tumor dose of 5360 cGy. With a median time to recurrence of 22 months, local failure (within 2 cm of original enhancing mass) was the predominant pattern of relapse (15 of 16 failures). The presence of radiographic residual disease seen on postoperative magnetic resonance imaging or computed tomographic scans was the most important prognostic variable for patients with intracranial ependymoma. Analysis of the 19 patients who underwent postoperative imaging revealed a 75 +/- 15% 5-year freedom from progressive disease for 9 patients with no residual disease, as compared with 0% freedom from progressive disease for the 10 patients with gross residual disease (P = 0.03). In contrast, the surgical assessment of residual disease was not significant (P = 0.4). Age at presentation was also a significant prognostic factor. The overall actuarial survival rate at 12 years for infants 24 months or younger at diagnosis was 0%, as compared with 62 +/- 13% for older patients (P = 0.03). For non-anaplastic ependymomas, complete surgical resection followed by local-field, high-dose (greater than 54 Gy) radiotherapy appears to offer the greatest chance for long-term survival. Because of the markedly reduced survival rate for patients with radiologically apparent postoperative disease, maximal surgical resection and novel therapeutic endeavors appear warranted for this high-risk group. Future protocols should use postoperative imaging, not operative reports, to stratify patients with ependymoma.

Adolescent↗
PubMed1991

Transfalcine approach to a callosomarginal artery aneurysm.

We describe a transfalcine approach to clipping and subsequently excising an expanding mycotic callosomarginal aneurysm. The patient had a devastating dominant (left) hemispheric spontaneous intracranial hemorrhage and was neurologically improving at the time of surgery nearly 2 months later. To avoid retracting the left hemisphere, we approached this left callosomarginal aneurysm from the nondominant side through the falx. The approach was straight-forward, and the result was satisfactory.

Adult↗
PubMed1991

Modified encephaloduroarteriosynangiosis as a surgical treatment of childhood moyamoya disease: report of five cases.

Moyamoya disease is an idiopathic disorder characterized by progressive occlusion of the internal carotid and anterior and middle cerebral arteries, with formation of an extensive abnormal collateral circulation at the base of the brain. Many neurosurgical procedures have been designed to bypass these occluded vessels. The results of one of these procedures, modified encephaloduroarteriosynangiosis was reviewed in five children followed for 3 1/2 to 19 1/2 years. Modified encephaloduroarteriosynangiosis performed unilaterally in one and bilaterally in four of the children, appeared to halt neurologic deterioration, despite angiographic progression, in four of the five children.

Brain Ischemia↗
PubMed1990

Choroid plexus tumors in the breast cancer-sarcoma syndrome.

Choroid plexus neoplasms are rare epithelial tumors of the central nervous system. A carcinoma of the choroid plexus occurred in a child from a family with the breast cancer-sarcoma syndrome (Li-Fraumeni or SBLA syndrome), an inherited condition characterized by the development of diverse neoplasms (sarcoma, breast cancer, brain tumors, leukemia, adrenal cortical carcinoma, and others). Choroid plexus carcinomas were identified in two kindreds previously reported with the syndrome. The literature contains reports of choroid plexus neoplasms occurring in families and in individuals with multiple primary tumors. Choroid plexus neoplasm may be a manifestation of the inherited proclivity to tumor development in the breast cancer-sarcoma syndrome.

Adolescent↗
PubMed1990

Myelopathy presenting decades after surgery for congenital cervical cutaneous lesions.

We report on two patients in whom cervical myelopathy developed decades after they had undergone surgery for congenital cervical cutaneous lesions. Preoperative magnetic resonance imaging demonstrated dorsal tethering and cavitation of the cervical cord in the area of the previous surgery and was helpful in decision making regarding surgical exploration and in planning for it. We stress the importance of long-term follow-up by both clinical examination and magnetic resonance imaging in children who have been operated on for cervical cutaneous masses that may have central connections.

Adult↗
PubMed1990

Preparation of an attenuated dengue 4 (341750 Carib) virus vaccine. II. Safety and immunogenicity in humans.

To determine safety and immunogenicity, a single 0.5 ml dose of a monovalent live-attenuated dengue (DEN) 4 (341750 Carib) vaccine was given sc to 3 groups of flavivirus nonimmune volunteers in increasing concentrations. Two recipients received 10(3) plaque forming units (PFU)/dose (1:100 dilution of stock vaccine). One remained asymptomatic, but became viremic between days 12 and 15, experienced a mild elevation of temperature (37.4 degrees C), and developed DEN-4 specific antibody. Neither recipient of the 10(4) PFU became infected. Eight volunteers then received undiluted vaccine (10(5) PFU). Viremia and antibody (neutralizing, hemagglutination inhibition, and IgM) developed in 5 of the 8 (63%). These 5 volunteers also developed a scarcely noticeable macular, blanching rash and minimal temperature elevations (37.3, 38.1, 37, 37.9, and 37.9 degrees C). Clinically insignificant decreases in total white blood cell, lymphocyte, and polymorphonuclear cell counts and an elevation in mononuclear cell counts occurred in association with viremia. This vaccine is safe, reasonably immunogenic, and suitable for further evaluation.

Adult↗
PubMed1989

Occipital infarction with hemianopsia from carotid occlusive disease.

Extracranial internal carotid artery occlusive disease usually produces stroke in the middle cerebral artery territory or the border zone between the middle and anterior cerebral arteries. It is unusual for occipital infarction in the posterior cerebral artery territory to be caused by internal carotid artery disease despite the fact that the posterior cerebral artery may arise directly from the internal carotid artery as an anatomic variation. We describe a patient with a fetal posterior cerebral artery originating from the internal carotid artery, and the initial manifestation of his extracranial internal carotid artery occlusive disease was hemianopsia from occipital infarction.

Aged↗
PubMed1989

Pre-irradiation chemotherapy for infants and children with medulloblastoma: a preliminary report.

From March, 1984, through June, 1987, 21 newly diagnosed children with high-risk medulloblastoma (Chang Stage T3 to T4) were treated on a 9-week postoperative, pre-irradiation chemotherapy regimen consisting of vincristine and cisplatin. The children over 2 years old then received radiation therapy. Six infants (aged 6 to 18 months) were maintained on chemotherapy consisting of MOP (nitrogen mustard, vincristine, and procarbazine) until the age of 2 years, at which time they were referred for irradiation. Of 13 children with measurable disease following surgery, five showed a definite response on computerized tomography scans to vincristine and cisplatin (one complete response and four partial responses) and five others showed clear marginal responses. Four of the six infants were disease-free at 19, 32, 35, and 57 months from diagnosis. One infant developed progressive disease at the completion of the vincristine and cisplatin course, and a second infant had progression during MOP administration. Three of the 21 children developed hearing loss within the speech frequencies during cisplatin treatments, but there were no other major toxicities. Fifteen children remained disease-free with a median follow-up period of 35 months (range 19 to 57 months). Chemotherapy given between surgery and radiotherapy may allow for the direct evaluation of a specific drug regimen and permit the postponement of radiation therapy in infants. Pre-irradiation vincristine and cisplatin was well tolerated and effective in shrinking the tumor in most children with medulloblastoma. Such chemotherapy regimens have the potential for extending long-term survival in high-risk children.

Adolescent↗
PubMed1988

Building-associated risk of febrile acute respiratory diseases in Army trainees.

Airborne transmission of infectious agents and associations of indoor air pollutants with respiratory illnesses are well documented. We hypothesized that energy conservation measures that tighten buildings also increase risks of respiratory infection among building occupants. At four Army training centers during a 47-month period, incidence rates of febrile acute respiratory disease were compared between basic trainees in modern (energy-efficient design and construction) and old barracks. Rates of febrile acute respiratory disease were significantly higher among trainees in modern barracks (adjusted relative risk estimate, 1.51; 95% confidence interval, 1.46 to 1.56), and relative risks were consistent at the four centers. These results support the hypothesis that tight buildings with closed ventilation systems significantly increase risks of respiratory-transmitted infection among congregated, immunologically susceptible occupants.

Adenovirus Infections, Human↗
PubMed1988

Antigenic variation of wild and vaccine rabies strains of Egypt.

Nineteen street rabies virus strains, isolated in Egypt from humans (two), dogs (nine), cats (two), farm animals (two), gerbils (three), and a jackal were antigenically analyzed. The Pasteur strain used for the preparation of human rabies vaccine, the Flury high and low egg passage stains (HEP, LEP) used for animal vaccines, and the challenge virus standard (CVS) strain were also assayed. All were examined by the indirect fluorescent antibody test, using a panel of 20 monoclonal antibodies against the nucleocapsid of rabies and rabies-related viruses. The rabies isolates demonstrated patterns of reactivity with the antinucleocapsid panel different from those of the Pasteur, HEP, and CVS strains. Representative human, dog, and rodent isolates were analyzed by neutralization tests in mice, with a second panel of 19 monoclonal antibodies against rabies and Mokola envelope glycoproteins. With this panel, the isolates demonstrated patterns of reactivity different from the vaccine strains. These data indicate antigenic variation between wild virus and vaccine strains.

Animals↗
PubMed1988

Segmental spinal dysgenesis.

Segmental spinal dysgenesis is characterized by focal agenesis or dysgenesis of the lumbar or thoracolumbar spine, with focal abnormality of the underlying spinal cord and nerve roots. Children are symptomatic at birth with lower limb deformities and neurological deficits that may be segmental. Myelography and computed tomography disclose hypoplastic or absent vertebrae and atrophic or absent neural elements adjacent to the bony deformity; the spinal column distal to the abnormality may be partially bifid, but is otherwise normal. Spinal ultrasonography was a helpful diagnostic adjunct in one patient. Surgery may be helpful in decompressing partially functioning spinal cord or nerve roots, but may exaggerate the tendency toward spinal instability. The embryology of this abnormality is not clear, but two children had other anomalies suggesting a spinal dysraphic syndrome, and its cause is probably related to a segmental maldevelopment of the neural tube.

Female↗