Search PubMed⌕ Search

Biomedical subjects

E Alexander

Publications and source records attributed to E Alexander.

At least 253 records · Page 14Linked to original sources
PubMed1978

Evaluation of BCNU and/or radiotherapy in the treatment of anaplastic gliomas. A cooperative clinical trial.

A controlled, prospective, randomized study evaluated the use of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and/or radiotherapy in the treatment of patients who were operated on and had histological confirmation of anaplastic glioma. A total of 303 patients were randomized into this study, of whom 222 (73%) were within the Valid Study Group (VSG), having met the protocol criteria of neuropathology, corticosteroid control, and therapeutic approach. Patients were divided into four random groups, and received BCNU (80 mg/sq m/day on 3 successive days every 6 to 8 weeks), and/or radiotherapy (5000 to 6000 rads to the whole brain through bilateral opposing ports), or best conventional care but no chemotherapy or radiotherapy. Analysis was performed on all patients who received any amount of therapy (VSG) and on the Adequately Treated Group (ATG), who had received 5000 or more rads radiotherapy, two or more courses of chemotherapy, and had a minimum survival of 8 or more weeks (the interval that would have been required to have received either the radiotherapy or chemotherapy). Median survival of patients in the VSG was, best conventional care: 14 weeks (ATG: 17.0 weeks); BCNU: 18.5 weeks (ATG: 25.0 weeks); radiotherapy: 35 weeks (ATG: 37.5 weeks); and BCNU plus radiotherapy: 34.5 weeks (ATG: 40.5 weeks). All therapeutic modalities showed some statistical superiority compared to best conventional care. There was no significant difference between the four groups in relation to age distribution, sex, location of tumor, diagnosis, tumor characteristics, signs or symptoms, or the amount of corticosteroid used. An analysis of prognostic factors indicates that the initial performance status (Karnofsky rating), age, the use of only a surgical biopsy, parietal location, the presence of seizures, or the involvement of cranial nerves II, III, IV, and VI are all of significance. Toxicity included acceptable, reversible thrombocytopenia and leukopenia.

Adolescent↗
PubMed1978

Effect of dose and dose schedule on the response of intracranial pressure to mannitol.

Analysis of monitoring records of 150 patients given over 1000 infusions of 20% mannitol delineared three variables affecting the response of intracranial pressure (ICP) to mannitol: the original ICP; the current dose; and the dose given over the preceding three hours. The level of ICP influenced the response to mannitol as much as the amount of mannitol; giving more mannitol than was required to bring ICP below 25 mm Hg led to the need for larger following doses. One hundred-milliliter-bolus doses were often as effective as larger doses. The results suggest that doses of mannitol given to control increased ICP should be kept as small as possible.

Humans↗
PubMed1977

Further observation on the fine structure of a colloid cyst of the third ventricle.

The fine structure of a surgically excised colloid cyst is described. The cyst was lined by ciliated and nonciliated columnar cells. The nonciliated cells contained secretory material and had a surface coating. In addition, a third type of smaller cell was seen wedged between the columnar cells and abutting on the basement membrane. These cells contained abundant free ribosomes and tonofilaments and displayed well developed desmosomes and half desmosomes. The cyst lining closely resembled the upper respiratory epithelium rather than neuroepithelium, thus supporting the contention that colloid cysts are derived from an endodermal source.

Adult↗
PubMed1977

Durometer for measurement of intracranial pressure.

The tensity of the skin over a supratentorial craniectomy was measured with a durometer placed on the skin flap. Tensity values were obtained on 124 occasions in 28 patients in whom lumbar or intracranial pressure was being recorded simultaneously. Corrections were made for differences in the level of the durometer and the level at which the device measuring lumbar or intracranial pressure was placed. The skin tensity and lumbar or intracranial pressure were then correlated and the correlation studied statistically. It was found that the durometer could be used to predict quantitatively the intracranial pressure with a very low standard error (estimation of +/- 28 mmH2O). An experimental model confirmed these findings. The system was less accurate at pressure below 68 mmH2O and above 680 mmH2O.

Craniotomy↗
PubMed1976

The adherence of human Fc receptor-bearing lymphocytes to antigen-antibody complexes. II. Morphologic alterations induced by the substrate.

The adhesion of human Fc receptor-bearing lymphocytes to immobilized antigen-antibody complexes is accompanied by marked alterations in cell shape, resulting in flattening of greater than 90% of the adherent cells. In addition, about 65% of the adherent cells become elongated, with distinct uropods being present in about 1/3 of these cells. Scanning electron microscopy demonstrates that most of the surface microvilli are lost, while ruffled membranes and long microextensions are formed during the shape change. Time-lapse cinematography shows that the major shape changes occur within a few minutes after contact with the substrate, and that the adherent cells undergo translational motility. Both flattening and elongation of the adherent cells are inhibited by low temperature, chelating agents, cytochalasin B, and vinblastine, while sodium azide selectively inhibits elongation and uropod formation. It is argued that these morphological changes result from an active response of the cell to the immobilized complexes, and that such alterations may be related mechanistically to the ability of the cells to kill antibody-coated target cells.

Antigen-Antibody Complex↗
PubMed1976

Evaluation of mithramycin in the treatment of anaplastic gliomas.

A controlled, prospective, randomized study evaluated the use of mithramycin in the treatment of anaplastic glioma compared to a similar group of patients receiving best conventional care. From a total of 116 patients in the study, 96 were within the valid study group. All patients were operated on, had histological confirmation of anaplastic glioma, and received radiotherapy at the discretion of the principal investigator. Fifty-two patients received mithramycin at a dose of 25 mug/kg/day for 21 days, while 44 patients were in the control group. There was no significant difference in the median survival from time of randomization in those receiving mithramycin (21 weeks) as compared to those not receiving mithramycin (26 weeks). There was no significant difference between the two groups in relation to age distribution, sex, location, diagnosis, tumor characteristics, signs or symptoms, or radiotherapy received. Duration of symptoms correlates positively with survival and was also significantly longer in the control group than in the treated group. This, however, did not account for the failure of mithramycin to be found an effective agent. Although the study was not designed to evaluate the efficacy of radiotherapy, patients who were so treated had a significant improvement in survival. The toxic complications of mithramycin included gastrointestinal symptoms, dermatological involvement, anemia, and liver dysfunction, indicating the need for close supervision.

Adult↗
PubMed1976

Posterior cervical fusion in chidren.

Six cases of posterior cervical fusion with rib grafts in children are reported. Four of the children had sustained cervical spine injuries in accidents, and two had congenital absence of the odontoid. Three-level fusions (C1-3) were done in four children, and four-level fusions (C1-4) in two. One child died of unrelated causes 3 months after the operation. The other five children have been followed for 5 to 13 years. All are doing well and each has a remarkably supple, stable neck and no neurological deficit.

Adolescent↗
PubMed1976

On the site of decreased fluid reabsorption after release of ureteral obstruction in the rat.

Fluid reabsorption in surface nephrons was studied by micropuncture 3 hours after release of complete left ureteral ligation (LUL) or after unilateral release of bilateral ureteral ligation (BUL). In 11 rats with LUL, glomerular filtration rate (GFR) averaged 0.23 +/- 0.04 ml. per minute in the experimental vs. 1.25 +/- 0.11 ml. per minute in the control kidney. GFR averaged 0.18 +/- 0.02 ml. per minute in BUL. Single nephron glomerular filtration rate (SNGFR) was decreased in the experimental kidney of LUL or BUL when determined at proximal or distal sites as compared to the SNGFR determined in shams or the left kidney following right ureteral ligation (RUL). Fractional water excretion was increased after release of obstruction. LUL 2.72 +/- 0.66 per cent; BUL 12.3 +/- 2.82 per cent when compared to sham-operated rats (0.48 +/- 0.07 per cent) or to the untouched kidneys of the RUL group (0.60 +/- 0.09 per cent). Despite increased water and sodium excretion after release of unilateral ureteral ligation and BUL there were marked differences in tubular fluid reabsorption between these two groups. Following release of LUL there was increased fractional water reabsorption along the accessible length of surface nephrons of the experimental kidney. At 55 per cent of proximal tubular length TF/Pin averaged 4.02 +/- 0.02 in LUL vs. 2.18 +/- 0.06 in shams. The mean TF/Pin at 90 per cent of distal tubular length was 31.0 +/- 1.37 in LUL vs. 10.6 +/- 0.08 in sham-operated rats. In contrast, water reabsorption after BUL was slightly but significantly suppressed proximally (TF/Pin 1.95 +/- 0.02) and markedly depressed distally (TF/Pin 3.35 +/- 0.29). These results suggest that the change in fluid reabsorption observed after relief of LUL is located at a site beyond the accessible length of surface nephrons, most likely in the collecting duct. However, the data could also be explained by alterations in fluid reabsorption in deep nephrons. The changes in fluid reabsorption seen following release of BUL reflect the additive effects of release of obstruction and a marked reduction in functioning nephron mass.

Animals↗