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Biomedical subjects

E Alexander

Publications and source records attributed to E Alexander.

At least 217 records · Page 12Linked to original sources
PubMed1985

Intact arch spondylolisthesis. A review of 50 cases and description of surgical treatment.

Over the past 11 years, the authors have treated 50 cases of intact arch spondylolisthesis. There were 38 female and 12 male patients, and all but 11 were older than 60 years of age. Almost all had severe low-back pain made worse by standing or walking. Other common manifestations were unilateral leg pain, numbness or weakness of the leg, and evidence of mild cauda equina compression. Severe cauda equina compression was rare. Myelography invariably showed an extradural dorsal compression. A waist deformity was characteristic in many patients, but 12 had a complete block. In 15 patients (30%) the myelographic impression was that of a herniated intervertebral disc. Most subluxations were of L-4 on L-5. At operation, the facets were found to be thickened, distorted, and irregular. All patients were treated with a wide decompression and laminectomy, which included a medial facetectomy of the inferior and superior facets. An intervertebral disc was removed in 10 patients. Follow-up monitoring of 41 patients (for an average period of 36 months) showed that 26 (63%) were pain-free, 11 had less pain, and four were unimproved. Five other patients with short follow-up periods (average 5 months) were all improved.

Aged↗
PubMed1985

Delayed CSF lavage for arteriographic and morphological vasospasm after experimental SAH.

Irrigation of the subarachnoid space after aneurysmal subarachnoid hemorrhage (SAH) has been reported to alleviate subsequent arterial vasospasm. The authors have investigated the effect of lavage of the cerebrospinal fluid (CSF) space in the two-hemorrhage canine model of vasospasm. Twelve dogs had basilar cistern lavage with 120 cc of artificial CSF 24 hours after each of two SAH's, and 12 control dogs had two sequential SAH's without intervening lavage of clot. The amount of clot on the ventral brain stem was evaluated at sacrifice and was graded from 0 (no clot) to 4 (maximum clot) to assess the adequacy of clot removal. Dogs that had undergone lavage had a median grade of 1 (range Grade 0 to 2); control dogs had a median grade of 2 (range Grade 1 to 3.5, p less than 0.001. Wilcoxon rank sum test), indicating significant reduction of gross clot by lavage. The neurological findings were graded from 0 to 5, based on meningismus, ataxia, paresis, and cranial nerve deficits. No significant differences in neurological grade were found on any day between the two groups. Satisfactory angiograms were obtained before and 7 days after hemorrhage and were controlled for blood pressure and blood gases; these showed significant spasm in both groups. There was a mean reduction (+/- standard deviation) of 21.6% +/- 16.2% in basilar artery diameter in control dogs, compared to a 28.8% +/- 15.1% reduction in dogs with lavage (difference not significant, t-test). There was a strong, but insignificant, trend toward reduction of endothelial desquamation in the basilar and middle cerebral arteries in dogs with lavage compared to control animals (p = 0.06). Corrugation and tearing of the elastica, thickened intima, intimal fibroplasia, vacuolization of the endothelial or smooth-muscle cells, and presence of blood cells in the adventitia occurred similarly in both groups. It appears that cisternal lavage 24 hours after hemorrhage in this model has no effect on the angiographic, neurological, or most morphological sequelae of SAH, in spite of evidence for removal of clot as seen at sacrifice. Any postulated interaction of clot and vessel resulting in chronic vasospasm must occur before this time. Evaluation of the effect of much earlier lavage (for instance, 1 hour after hemorrhage) may elucidate the point at which vasospasm is instigated after SAH, and help in determining what factors cause vasospasm.

Animals↗
PubMed1984

Limitations of the radioimmunoprecipitation polyethylene glycol assay (RIPEGA) for detection of filarial antigens in serum.

The performance of the radioimmunoprecipitation polyethylene glycol assay (RIPEGA) was examined for quantitation of filarial antigens (Brugia malayi and Dirofilaria immitis) in serum from infected human and animal hosts and non-infected controls. Multiple PEG concentrations were employed to determine the level of non-specific binding (NSB) in non-exposed human sera (NEHS) containing no filarial antigen. The NSB observed when 3 different 125I-labeled IgG antibodies were added to 26 NEHS varied 3-fold and was correlated significantly with total serum IgM (r = 0.80, P less than 0.005, n = 24) but not with serum IgA (r = 0.37) or IgG (r = 0.45). NSB levels were significantly reduced when a Fab'2 fragment of the 125I-labeled antibody was used, but the correlation of NSB with total serum IgM remained significant (r = 0.57, P less than 0.01). The presence of rheumatoid factor in NEHS sera also significantly increased NSB by an average of 3-fold. These effects eliminated the assay's ability to detect in sera from infected hosts filarial antigen the presence of which could be readily demonstrated by an immunoradiometric assay. The RIPEGA's precision (intra-assay coefficient of variation (CV) = 21% at 35% Bmax) and reproducibility (inter-assay CV = 29% at 35% Bmax) are less satisfactory than many alternative immunoassays. In many cases, positive sera failed to dilute out in parallel with each other or with an antigen-spiked standard reference curve. We conclude that poor performance characteristics currently limit the utility of the RIPEGA for quantitating filarial antigen in human and animal serum.

Animals↗
PubMed1983

Comparisons of carmustine, procarbazine, and high-dose methylprednisolone as additions to surgery and radiotherapy for the treatment of malignant glioma.

Within 3 weeks of definitive surgery, 609 patients with histologically demonstrated, supratentorial malignant glioma were randomized to receive, in addition to 6000 rads of radiotherapy, one of four treatment regimens: carmustine (BCNU), high-dose methylprednisolone, procarbazine, or BCNU plus high-dose methylprednisolone. We analyzed the data for the total randomized population and for the 527 patients (87% with glioblastoma multiforme) in whom the initial protocol specifications were met (the valid study group). Significantly longer survival was experienced by patients receiving procarbazine or BCNU alone compared to those receiving only high-dose methylprednisolone. No other pairwise comparisons demonstrated differences significant at the 0.05 level. However, the combination of BCNU plus high-dose methylprednisolone tended to be less effective than BCNU alone in patients with poor prognosis. This study indicates that BCNU and procarbazine are moderately useful agents in conjunction with radiotherapy for patients with malignant glioma. In addition, future protocols may allow use of corticosteroids in conventional dosages for treating cerebral edema and controlling symptoms; conclusions based on survival as the endpoint are unlikely to be affected by administering steroids at somewhat greater than the usual dose. More effective regimens for the treatment of malignant glioma should be sought.

Adolescent↗
PubMed1982

Brainstem hemorrhages and increased intracranial pressure: from Duret to computed tomography.

In the late nineteenth century, Henri Duret produced minute brainstem hemorrhage in dogs by rapidly increasing their intracranial pressure. Whether those hemorrhages were the same as those seen today associated with transtentorial herniation is not agreed upon, and the term Duret's hemorrhages is rarely used. Duret's report on his experiments is condensed here and the value of computed tomography for detecting brainstem hemorrhages is illustrated by a case report.

Brain Stem↗