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Biomedical subjects

J A Epstein

Publications and source records attributed to J A Epstein.

At least 91 records · Page 5Linked to original sources

Responses of the socially anxious to the prospect of interpersonal evaluation.

We predicted that socially anxious people who are faced with the prospect of an interpersonal evaluation will act in an inhibited and withdrawn way. Subjects who scored low or high on a measure of social anxiety told four stories about themselves to an interviewer. In the anticipated-evaluation condition, the subjects learned that after they had told their stories, the interviewer would tell them her impressions of them. In the control condition, no mention was made of an evaluation. Judges rated transcripts of the stories. As predicted, socially anxious subjects who thought they were going to be evaluated (relative to anxious subjects in the control condition and nonanxious subjects in both conditions) told shorter stories, and the events in their stories were commonplace rather than unique. Their stories were also less revealing about them as individuals, and less vivid. Contrary to a second prediction, socially anxious subjects who expected to be evaluated did not act any less inhibited or withdrawn when their interviewers were described as very trusting than when they were described as very wary. Implications are discussed.

Adult↗

Intradural disc herniations in the cervical, thoracic, and lumbar spine: report of three cases and review of the literature.

The clinical, neuroradiological, and surgical management of three cases of intradural disc herniations--one each in the cervical, thoracic, and lumbar regions--are presented. Intradural disc herniations comprise only 0.27% of all herniated discs. Three percent occur in the cervical, 5% in the thoracic, and 92% in the lumbar spinal canal. Those with cervical or thoracic lesions frequently exhibit profound myelopathy, whereas those with lumbar lesions demonstrate radicular or cauda equina syndromes. Although varying combinations of the MRI, non-contrast CT, myelogram, and myelo-CT scans may at times fail to accurately establish the diagnosis of an intradural disc herniation prior to surgery, the index of suspicion raised by the lack of clinical correlation with surgical findings justifies an intradural exploration.

Adult↗

Treatment of fractures of the vertebral limbus and spinal stenosis in five adolescents and five adults.

Fractures of the vertebral limbus occur between the vertebral ring apophyses and the cartilaginous rim of the superior or inferior margins of the vertebral end plates. These fractures are typically seen in adolescents or young adults, since fusion in this area is not complete until the ages of 18 to 25. Of 85 cases reported, 24 occurred in adolescents. The authors present the clinical, neurodiagnostic, and surgical management of fractures of the vertebral limbus and coincident segmental spinal stenosis in a group of 5 adolescents and 5 adults. An additional category for fractures of the vertebral limbus is proposed, namely, a lesion that is not confined to the superior or inferior margins of the vertebral end plates, but that spans the full length of the vertebral body.

Adolescent↗

Coexisting cervical spondylotic myelopathy and bilateral carpal tunnel syndromes.

In six patients, operations for bilateral carpal tunnel syndromes (CTS) were performed or were about to be performed without the awareness of the presence of underlying cervical spondylo-stenosis. Only later, when symptoms of myeloradiculopathy were recognized, was the diagnosis confirmed and decompressive laminectomy performed. Because the symptoms of CTS may resemble or be masked and accentuated by the cervical disorder, patients with the presumed diagnosis of bilateral CTS should undergo appropriate critical neurologic, electrodiagnostic, and neuroradiologic (magnetic resonance imaging, computed tomography, myelo-computed tomography) assessment. If these guidelines are followed, the radiculopathy caused by cervical pathology will be appropriately recognized and treated, possibly averting the need for carpal tunnel decompression or modifying treatment.

Aged↗

Nicotine gum and self-help manuals in smoking cessation: an evaluation in a medical context.

This study evaluated the effectiveness of nicotine chewing gum in smoking cessation, when incorporated into a behaviorally oriented self-help program. One hundred ninety-seven patients were randomly assigned to nicotine gum with a self-help manual, a self-help manual without gum, or a control condition, but received no further treatment from the prescribing physician. At six weeks, the nicotine gum group was superior to both the self-help and control conditions. By one year, many gum patients had relapsed, and the treatment effect was no longer significant. Patients who were able to quit initially were most likely to remain ex-smokers in the self-help condition. The clinical importance of these findings is discussed.

Adolescent↗

The surgical management of cervical spinal stenosis, spondylosis, and myeloradiculopathy by means of the posterior approach.

No firm statistical evidence exists establishing the superiority of the anterior or the posterior approach in the management of spondylostenosis, although some sense of order is evolving. In general the consensus suggests that in spondylostenosis, the anterior approach may be preferred for disc or segmental osteophyte intrusions limited to one or two levels. Laminectomy is the preferred procedure in patients with a narrowed canal and multiple level involvement. The surgeon's personal preference and experience remains the dominant factor. Patients with congenital stenosis involving all of the major segments, with or without superimposed developmental changes, require more extensive laminar decompression with proper attention to the craniocervical junction where anomalies may occur. The success of laminectomy is dictated by the preservation of cervical lordosis. In patients with major dorsally located abnormalities such as hyperlordosis, shingling, and arthrosis with hypertrophy of the yellow ligaments, posterior decompression is essential. Subsequent stabilization is rarely required with proper surgical and postoperative care. Both an anterior and posterior approach may be indicated in unique circumstances of spondylostenosis complicated by subluxation and instability.

Humans↗

Spinal stenosis and disc herniation in a 14-year-old male. A case report.

Spinal stenosis should be considered in the differential diagnosis of disc disease when evaluating an adolescent presenting with unrelenting back and leg pain. Although they typically exhibit mechanical signs alone without neurological findings, they nevertheless may prove more vulnerable to rapidly progressive neurological changes. If motor deficits occur, protracted courses of conservative care should be avoided, and proper surgical management considered. Our recent experience with a 14-year-old boy with disc disease and stenosis indicated that aggressive surgical management facilitates a rapid return to an asymptomatic existence.

Adolescent↗

Ouabain-resistant, amiloride-sensitive Na+-K+ pumping activity and morphological changes are inducible.

The functional expression of a ouabain-resistance gene has been studied in a transfected cell line, OR-6 cells. These cells possess a ouabain-inhibitable, amiloride-resistant Na+-K+ pump under control conditions. They can be induced by brief culture in the presence of low concentrations of ouabain to express a ouabain-resistant, amiloride-sensitive Na+-K+ pumping activity. They revert to the uninduced phenotype shortly after removal of ouabain from the culture medium. When placed in low-potassium, low-serum, or dibutyryl adenosine 3'-5'-cyclic monophosphate-containing media, these cells produce long cellular extensions. Thus a single inducible gene appears to regulate sensitivity of the Na+-K+ pumping activity to cardiac glycosides and to amiloride, and it may be related to important characteristics of cellular morphology.

Amiloride↗

Inhibition of chloride secretion by BaCl2 in the rectal gland of the spiny dogfish, Squalus acanthias.

In the rectal gland of the spiny dogfish (Squalus acanthias), chloride enters the cell via a cotransport system together with sodium and potassium in a 2 Cl-: 1 Na+: 1 K+ stoichiometry. The system is energized by the electrochemical potential for sodium directed into the cell. Sodium is extruded from the cell by Na-K-ATPase located on the basolateral cell membrane. Chloride leaks into the lumen following a favorable electrical gradient. Potassium is thought to recirculate across the basolateral cell membrane. Since barium ions inhibit the efflux of potassium from cells we used barium chloride to explore the role of potassium in the process of stimulated secretion of chloride by the gland. The secretion of chloride was stimulated with theophylline 2.5 X 10(-4)M and dibutyryl cyclic AMP 5 X 10(-5)M. Ba++ inhibited the secretion of chloride in a way that was reversible and dose dependent. The reduction in secretion was associated with a parallel fall in transglandular electrical potential. Inhibition was half maximal at a concentration of Ba++ of 10(-3)M. The reduction in efflux of potassium produced by Ba++ presumably decreases the potassium diffusion potential, thus reducing the electronegativity of the cell and dissipating the driving force for chloride across the apical cell membrane. Recirculation of K+ across the basolateral border of the cell would thus be essential for the maintenance of chloride secretion by the gland.

Animals↗

Simultaneous occurrence of herniated disc and mesothelial cyst in a 16-year-old male.

The unusual, simultaneous occurrence of both a herniated disc and an intraspinal mesothelial cyst in an adolescent is reported. The patient was a 16-year-old white male who presented with sciatic pain in his left lower extremity. Myelography revealed evidence of a left L4-5 discal herniation, and a L5-S3 midline sacral lesion that proved to be a mesothelial cyst.

Adolescent↗

Unilateral S-1 root compression syndrome caused by fracture of the sacrum.

Unilateral S-1 nerve root compression after an S-1 sacral fracture was found in an 18-year-old man after a motor vehicle accident. The positive myelogram, myelogram-computed tomogram, and magnetic resonance studies led to surgical intervention. Marked bony callous formation contiguous with the S-1 alar fracture protruded into the canal and was responsible for tethering the S-1 nerve root. A right L-5 hemilaminectomy, an L-4, L-5 and L-5, S-1 medial facetectomy, and foraminotomy facilitated nerve root decompression. Postoperatively, the patient was markedly improved. The authors suggest a more aggressive attitude in the diagnostic, radiographic, and surgical management of sacral fractures now that more specific technical facilities are available to define the precise character of the lesions involved.

Adolescent↗

Coexisting cervical and lumbar spinal stenosis: diagnosis and management.

An attempt has been made to identify and manage patients symptomatic from both cervical and lumbar spinal stenosis. The order of operative intervention was related to the degree of myelopathy and radiculopathy. Patients requiring cervical surgery first had absolute stenosis with a spinal canal equal to or less than 10 mm in anteroposterior diameter. Those requiring lumbar surgery first presented with stenosis and a canal between 11 and 13 mm in depth. In the latter group, patients presented with radiculopathy in their upper and lower extremities. A significant portion (50%) had intermittent neurogenic claudication (INC). Motor and sensory changes were severe in those with absolute as compared to relative stenosis. After cervical laminectomy, myelopathy improved or stabilized, and the subsequent lumbar decompression could be completed with less risk. Cervical cord decompression often resulted in improvement in lumbar symptoms with resolution of pain, spasticity, and sensory deficits of myelopathic origin. However, latent symptoms of INC caused by lumbar stenosis were not affected by cervial decompression and increased in severity. Electrodiagnostic studies were helpful in that somatosensory evoked potentials showed conduction delays in the cervical cord in patients with significant disease. The identification of motor neuron disease and peripheral neuropathies was essential. The surgical management included extensive, multiple level laminectomy, unroofing of the lateral recesses, and foraminotomy. Neurolysis and untethering of the spinal cord was essential. Significant improvement was shown by 90% of these patients.

Aged↗

Ouabain binding in rectal gland of Squalus acanthias.

In an attempt to examine the mechanisms of activation of (Na, K)-ATPase when epithelial transport is stimulated, the binding of ouabain to rectal gland tissue was measured before and after stimulation with dibutyryl cAMP and theophylline. Stimulation significantly altered the characteristics of ouabain binding to slices of Squalus acanthias rectal gland and to isolated rectal gland cells, accelerating the rate of binding and increasing the amount of ouabain bound at equilibrium when low concentrations of ouabain (10(-9) to 10(-7) M) were present in the medium. Scatchard plots of ouabain binding were nonlinear, suggesting at least two classes of binding sites, one of higher and one of lower affinity. Stimulation with cAMP and theophylline appeared to increase the affinity of the high-affinity site. Ouabain binding was increased by cAMP and theophylline even in the presence of furosemide (10(-4) M) or bumetanide (10(-5) M), and when Li+ was substituted for Na+, or NO3- for Cl- -maneuvers known to inhibit rectal gland secretion. The changes in ouabain binding induced by cAMP and theophylline do not appear, therefore, to be secondary to secretory activity but may reflect a change in the configuration, environment or location of existing enzyme so as to enhance its activity. Stimulation of ouabain binding cannot be demonstrated in whole homogenates of rectal gland, indicating that intact cells are necessary for the cyclic AMP-induced increase in ouabain binding to become manifest.

Animals↗