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Biomedical subjects

M Salcman

Publications and source records attributed to M Salcman.

At least 19 recordsLinked to original sources
PubMed1992

Multiple intracerebral arteriovenous malformations: report of three cases and review of the literature.

Multiple intracerebral arteriovenous malformations are thought to be exceedingly rare lesions and have usually been reported as single cases. During the past 2 years, we have treated three patients with multiple cerebral arteriovenous malformations, representing 3.2% of a consecutive series of 95 arteriovenous malformation patients seen since 1976. Details on 17 other cases are available in the literature and are summarized here. The incidence of multiple arteriovenous malformations in major series ranges from 0.3% to 3.2%; the average incidence is 1.9% based on 21 cases encountered in a total population of 1102 arteriovenous malformation patients. Patients with multiple arteriovenous malformations often have other vascular anomalies of the brain or soft tissues, but the clinical mode of presentation, age, sex, and anatomical distribution of the lesions are the same as those of patients with single arteriovenous malformations. The use of four-vessel angiography in combination with magnetic resonance imaging may result in a higher detection rate for such cases.

Adult↗
PubMed1992

Extraskeletal myxoid chondrosarcoma of the falx.

Intracranial cartilaginous tumors are unusual lesions, of which myxoid chondrosarcoma is the rarest. We describe this tumor arising from the falx in a 28-year-old woman treated at recurrence with a second operation and a radiation implant. The behavior of classic chondrosarcoma and mesenchymal chondrosarcoma is also reviewed.

Adult↗
PubMed1979

Probability and the brain.

Probability theory asserts the lawfulness of seemingly random events in large populations and seems to be a reasonable approach to a general understanding of the structure and function of the nervous system. The brain, by virtue of the number of its components, the multiplicity of their possible interconnections, and the range and rapidity of their outputs, is almost implausably complex in its over-all design. Probability theory, therefore, is usually applied to (a) descriptions of the behavior of large neuronal populations, (b) statistical analysis of neuronal spike trains, and (c) theoretical models of neuronal interaction. A consideration of each of these subjects is presented, as is a discussion of the most fundamental level of application of the theory to the nervous system: (d) the assertion that the neuron and/or brain is inherently nondeterministic. In practical terms this is shown to be a "nonissue," the uncertainty principle that follows has rather definite philosophical implications.

Auditory Perception↗
PubMed1979

Correlation of absorption coefficients with intracranial fluid protein concentrations and specific gravities.

Samples of ventricular cerebrospinal fluid, tumor cyst fluid, and subdural fluid were obtained from 30 patients at operation. The protein concentration and the specific gravity of each sample were measured and the corresponding mean absorption numbers were calculated from the numerical printout of the preoperative computerized tomogram. For fluids with a specific gravity greater than 1.005, a linear relationship was demonstrated between protein concentration and specific gravity. For protein concentrations greater than 300 mg/dl, there was a linear relationship between protein concentration and the mean absorption number. As the precision of present instrumentation improves, it is expected that a noninvasive technique for estimating intracranial protein concentration will have a number of clinical application.

Absorption↗
PubMed1979

Nelson's syndrome: one disease or two?

We present a case of Nelson's syndrome in which the clinical, radiographic, and surgical findings are indicative of a discrete microadenoma rather than of diffuse pituitary hyperplasia. Ultrastructural analysis reveals this to be the first example of a sparsely granulated lesion in Nelson's syndrome and only the second such adrenocorticotropic hormone-secreting tumor reported. Unfortunately, there do not seem to be any firm ultrastructural features that differentiate between hyperplasia and discrete adenoma. Separation of the two entities may be important in delineating the pathogenesis and treatment of Nelson's syndrome; these are discussed.

Adenoma↗
PubMed1978

Neuropathological changes in cerebellar biopsies of epileptic patients.

In 5 patients with pharmacologically intractable epilepsy, biopsy of the cerebellar cortex at the time of surface electrode implantation for therapeutic stimulation demonstrated marked degeneration of the Purkinje cell layer in every case. Two of the patients had never experienced a generalized convulsion. Comparison of these biopsy findings with the autopsy findings in two other groups of patients with a seizure disorder of different duration and severity and with the findings in other reported series suggests that permanent neuronal damage in epilepsy is related to the cumulative effects of the frequency and chronicity of the disorder. The pathogenesis remains unclear. The histopathological changes are identical to those seen in generalized cerebral hypoxia, but the observations in our series support the view that in epilepsy the pathogenesis may not be hypoxic.

Adolescent↗
PubMed1978

Experimental spinal cord trauma, I: Correlation of blood flow, tissue oxygen and neurologic status in the dog.

Spinal cord blood flow and tissue oxygen were measured concurrently in a series of paraplegic dogs subjected to experimental spinal cord trauma. Injury to the spinal cord sufficient to cause clinical paraplegia is associated with a significant (P less than 0.01) decrease in blood flow in the central spinal cord from 15.2 to 6.1 ml/min/100gms at two to three hours following injury. Also, at two and three hours post-injury, paraplegic dogs demonstrate a significant (P less than 0.01) decrease in tissue oxygen levels from 35-39 mm Hg to 17-24 mm Hg. No significant changes occurred in systemic blood pressure or carotid blood flow. A delay often precedes the significant onset of blood flow and tissue oxygen alterations, which suggests that therapeutic efforts could be directed during this critical interval.

Animals↗
PubMed1978

Experimental spinal cord trauma, II: Blood flow, tissue oxygen, evoked potentials in both paretic and plegic monkeys.

Graded clinical motor deficits were produced in a series of Rhesus monkeys subjected to experimental spinal cord trauma from a variety of impact loads. An argon washout technique was used to measure spinal cord blood flow; tissue oxygen carbon dioxide, and somatosensory evoked potentials (SEPs) were also monitored. Each animal received a clinical grade and, after a week of study, the spinal cords were removed for histopathological grading. Blood flow in paraplegic animals was significantly decreased at two hours and seven days following injury (5 ml/min/100 gms tissue); paraparetic animals showed no significant difference from preinjury levels (14 ml/min/100 gms tissue). Animals which completely recovered demonstrated increased flow (27 ml/min/100 gms tissue). Composite tissue oxygen was generally depressed in paraplegic animals (28 mm Hg/kg) but showed no clear pattern in other groups. Only 8% of monkeys rendered paraplegic preserved a somatosensory evoked potential (SEP) at five minutes after injury. Paraparetic animals were more likely (40%) to show initial preservation of the SEP and in normal animals, the SEP always returned by three hours. Histopathological grading tended to parallel clinical grading in 92% of the cases. Although the extremes of possible postinjury deficits (complete paraplegia or recovery) can be predicted from a combination of these measurements, incomplete lesions (whether judged clinically or pathologically) present a more variable picture.

Animals↗
PubMed1978

Experimental spinal cord trauma, III: Therapeutic effect of immobilization and pharmacologic agents.

A wide variety of pharmacologic agents has been suggested to serve as therapeutic adjuncts in the management of acute spinal cord trauma. The present study was conducted to determine what effect, if any, these agents have when they are added to immobilization of the spinal column, the most widely used clinical measure. Rhesus monkeys were subjected to different levels of experimental spinal cord injury with and without subsequent immobilization by means of a figure of eight ligature. In the control group, five of six animals impacted at 500 gm-cm were paraplegic. In the immobilized animals, three of four animals impacted at 500 gm-cm recovered completely and the fourth was only mildly paraparetic. Paraplegia could not be uniformly produced in this group until 800 gm-cm forces were routinely employed. In the second phase of the study, only immobilized animals were used, with and without drug therapy. No change in the force-injury curve, above and beyond that from immobilization, can be demonstrated for monkeys given dextran, phenobarbital, methyldopa, phenoxybenzamine or vasopressors. The pathophysiologic concepts upon which such agents are advocated should be reassessed. Spinal immobilization can significantly improve the clinical outcome following experimental spinal cord injury, it may also serve to control some of the variability previously observed in pharmacologic experiments.

Animals↗
PubMed1977

Prognosis of surgically treated intracranial arterial aneurysm patients.

From 1969 to 1973, we undertook a direct surgical therapeutic approach with 62 patients who had intracranial aneurysms. The surgical mortality for patients in the first three clinical grades was 5%. Sixty-eight percent of the entire group of patients had improved conditions at follow-up. When these results are compared to the expected outcome of the natural course of the disease under conservative management, the superiority of the direct approach is seen. With the aid of modern instrumentation, anesthesia, steroid therapy, and magnification, neurosurgical centers handling a reasonable volume of these cases should achieve comparable results.

Blood Pressure↗