Biomedical subjects
Publications and source records attributed to R Glick.
1. Stimulation of brain cell growth by fetal plasma is reduced when levels of IGF-I are low and IGFBP-1 are high. 2. Fetal brain cells respond to IGFs in cell culture, and effects of plasma are reduced by addition of IGFBP-1. 3. Increased levels of IGFBP-1 and reduced availability of IGF-I may contribute to reduced brain growth when maternal nutrition is impaired.
In vitro studies suggest that insulin-like growth factor I (IGF-I) may modulate hepatic production and peripheral utilization of lipoproteins. We measured blood concentrations of IGF-I; total, high-density-lipoprotein, and low-density-lipoprotein (LDL) cholesterol; and apolipoproteins in 18 women with above average cholesterol after high- and low-fat diet periods. Total cholesterol fell 6% (P less than 0.02) during the low-fat diet because of reduced concentrations of LDL cholesterol (P less than 0.01). Serum concentrations of IGF-I were inversely correlated with total and LDL cholesterol and apolipoprotein B during both high-fat (r = -0.676, P less than 0.005; r = -0.745, P less than 0.001; and r = -0.504, P less than 0.04, respectively) and low-fat (r = -0.656, P less than 0.005; r = -0.757, P less than 0.001; and r = -0.695, P less than 0.001, respectively) diets. IGF-I increased with reduced fat intake in obese subjects only. Thus, IGF-I may contribute to the regulation of LDL cholesterol in mildly hypercholesterolemic women but may not mediate the beneficial response to reduced fat intake.
Eight patients with atlantoaxial instability secondary to trauma or rheumatoid arthritis were treated with posterior C1-C2 arthrodesis using the Halifax interlaminar clamp and autogenous bone graft or methylmethacrylate. Thus far, with an average follow-up of 6 months, satisfactory stability has been achieved with no instrument failure.
Phenylpropanolamine (PPA) is the major ingredient in more than 70 over-the-counter preparations including diet pills, nasal decongestants, and the legal "look-alike" stimulants. Structurally and functionally similar to amphetamine and ephedrine, PPA has recently been associated with several neurological manifestations including psychosis, stroke, severe headache, seizures, and intracerebral hematoma. We report a case of intracerebral hematoma and subarachnoid hemorrhage in a young woman with angiographic and biopsy-proven vasculitis of the central nervous system (CNS) induced by PPA in her diet pills. From review of the literature, we distinguish drug-induced vasculitis as a separate entity from primary CNS vasculitis, both clinically and pathologically. This report should alert physicians, in general, to this potentially fatal side effect of PPA, a commonly used over-the-counter drug. Also, neurosurgeons in particular should consider the possibility of drug-induced vasculitis when faced with cases of intracerebral or subarachnoid hemorrhage without apparent cause.
A procedure is described for the isolation and purification of E. coli plasmid DNA by polyethylene glycol precipitation. The method is rapid, simple, inexpensive and amenable to both small and large scale manipulation. This procedure involves lysis of bacterial cells by treatment with pronase in sodium dodecyl sulfate, removal of chromosomal DNA by centrifugation, precipitation of residual nucleic acids with polyethylene glycol and removal of RNA by precipitation with LiCl. Plasmid DNA purified as described is pure enough for restriction endonuclease analysis, for use as a vector for the cloning of cDNA or synthetic DNA, or for use as a template in an E. coli transcription-translation cell-free system.
Over a three-year period, we have seen in consultation four children whose mothers cited complaints referable to every organ system and which had persisted for many years. The parents had consulted a total of 99 physicians in eight states. Absence from school ranged from 40 to 200 days a year. Physical examinations of all patients and extensive and repeated laboratory studies were normal. On psychiatric examination the mothers exhibited paranoid thinking and a conviction of serious medical illness in their child which approached delusional proportions. They resisted psychiatric consultation and refused psychotherapy. The mother-child relationship was remarkably symbiotic, the two teen-age patients essentially voicing complaints which were indistinguishable from those reported by their mothers. The fathers invariably supported their wives' concerns. Subsequently, parents and children left treatment, continuing to "doctor shop." Long-standing multisystem complaints in a child with normal growth and maturation are incompatible with any known significant organic disease, but suggest a serious emotional problem within the family. Further, parents who take such children from doctor to doctor are frequently disturbed themselves and may use an offspring as a proxy patient. An accurate diagnosis depends on careful history-taking from parents, patient, health professionals, and schools.
epsilon-Aminocaproic acid (EACA) has been used to prevent rebleeding in patients with intracranial aneurysms because it crosses the blood-brain barrier and is an inhibitor of fibrinolysis. Recommended doses have ranged from 24 to 48 g/day. We now describe an inhibitory effect on platelet function at the higher dose range. In vitro, a dose-dependent inhibition of adenosine diphosphate- and collagen-induced platelet aggregation was observed with concentrations of EACA beginning at 7.6 mM. In vivo, prolongation of the template bleeding time was observed in all eight patients receiving 48 g/day (greater than 20 minutes in four), in all five on 36 g/day (greater than 20 minutes in three), and in none of seven on smaller doses. More importantly, rebleeding and excessive intraoperative bleeding (requiring more than 1 litre of blood replacement) occurred predominantly in patients receiving the larger doses of EACA. Within 48 hours of the discontinuation of EACA, the bleeding times returned to normal values in all but one patient. We conclude that EACA exerts a dose-dependent inhibitory effect on platelet function and that patients receiving doses in excess of 24 g/day may be at risk of serious bleeding. Patients receiving EACA should be monitored with serial bleeding time tests.
Numbers of synapses were compared in the cerebellar cortex of adult (12 months of age) and senescent (25 months of age) male rats of the Fisher-344 strain. The total number of axodendritic synapses was found to be 24% lower in the senescent rats as compared with adults. A differential analysis of synapses involving dendritic shafts and spines showed no significant change in numbers of synapses involving shafts, but a highly sigificant 33% decrease in numbers involving spines in senescent rats. These data suggest that the selective age-related loss of synapses involving dendritic spines (but not shafts) in the cerebellar cortex results from the impairment with advanced age of specific afferent neurons and/or a selective age-related vulnerability of dendritic spines.
The purpose of the present experiment was to test the hypothesis that flat surface information for the plane of projection is the essential difference between ordinary and pictorial perception. Adults were asked to make relative size judgments of pairs of squares and triangles placed and pictured at various distances. The conditions were: real scene controls, life-size slides and prints, and real scenes viewed through clear glass, textured glass, a screen and a 50-mm lens. The error rate was significantly lower with real scenes than with either slides or prints which did not differ. The control data for real scenes were used for comparison to test for the effects of interposed flat surfaces on size judgments of real scenes. Viewing real scenes through either a clear glass pane or a 50-mm lens increased the error rate two and one-half times that of the controls for real scenes. Neither textured glass nor a screen significantly affected error rate. Results were interpreted as supporting the hypothesis that information about a flat surface for the plane of projection is the critical variable determining the special character of picture perception.
Perception of size, linear, and texture perspective was investigated in third-grade and sixth-grade children and in college adults in three separate studies. A matching task required the observer to choose from a set of four alternative real scenes the correct match for the test stimulus, which was either a picture or a real scene. Correct performance required that the subject utilize perspective information for both size and distance distance relations. Erroneous choices available to the subject indicated errors in size judgement, in distance judgment, or in both simultaneously. View was either restricted at the correct station point or was free, with head motion. There were no significant effects of grade level. For all three groups, mean percent correct was nearly 100% with the real-scene test stimuli, and significantly below the chance level with the picture test stimuli. Errors in size judgment occurred most frequently, indicating that the geometrically correct rate of perspective convergence was too rapid to be seen by the subjects as perceptually acceptable. With size-perspective information alone, the number of size plus distance errors also increased significantly. There was no significant effect of viewing condition.
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The term craniovertebral junction refers to an area comprising the inferior portion of the occipital bone surrounding the foramen magnum and the first two cervical vertebrae. A variety of anomalies of bony, meningeal, and neural elements are known to occur in this region, producing a wide spectrum of clinical symptoms. These can range from dizziness, ataxia, and nuchal headaches to obvious quadriparesis and cranial nerve palsies. Often the symptoms are vague with an evolution marked by temporary exacerbations and remissions. The diagnosis can be difficult, and in our experience is best achieved by combining a neurotologic and neurologic evaluation. We discuss here the symptoms and diagnosis in ten patients with lesions at the craniovertebral junction. The surgical management of two cases of basilar invagination is described, and the controversies regarding the technique are discussed.
Although research has established a strong association between premenstrual dysphoric symptoms and depression, there is little data on the effect of antidepressents on premenstrual symptoms. This study compared the efficacy of three treatments--imipramine, phenelzine, and placebo--on the premenstrual symptoms of women with atypical depression who had responded to treatment for their depressive symptoms. The Premenstrual Assessment Form (PAF) was used to rate the type and degree of premenstrual symptomatology. After 12 weeks, at least two-thirds of the women on active medication showed improvement on most measures of premenstrual symptoms to the degree that they had essentially no premenstrual problems after treatment. By comparison, only half of a group of women who had responded to placebo treatment of 6 weeks duration showed such improvement.
We report a case of unilateral frostbite arthritis in a 58-year-old male. Clinical and radiological changes mimicked those of erosive osteoarthritis. Patients with this presentation should be carefully questioned for a history of exposure to cold, and frostbite arthritis should be considered in the differential diagnosis.