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Biomedical subjects

J J Stein

Publications and source records attributed to J J Stein.

At least 19 recordsLinked to original sources
PubMed1996

Distribution and coverage of beta cells in the cat retina.

We have reexamined the retinal distribution and dendritic field dimensions of beta cells in the cat retina. Beta cells were labeled by retrograde transport from the A-layers of the lateral geniculate nucleus and distinguished from alpha cells on the basis of soma size. Dendritic fields of beta cells were visualized by intracellular staining in vitro. The fraction of cat ganglion cells that were beta cells varied with retinal location. Except near the area centralis, beta cells represented about half of all ganglion cells in the nasal hemiretina. They contributed as heavily as the other major ganglion cell classes to the nasal visual streak. In and near the area centralis and in the temporal retina, beta cells represented about two-thirds of all ganglion cells. The areas of beta cell dendritic fields were reciprocally related to beta cell density. For example, they were 3-fold smaller within the visual streak than at matched eccentricities outside it. For many cells, we could estimate both local beta cell density and dendritic field area. Coverage factor (dendritic field area x local density) remained constant at about 4 despite 100-fold variations in beta cell density, and was independent of eccentricity, nasotemporal location, or position relative to the visual streak. Analysis in terms of sampling theory suggests that the beta cell array is matched to X-cell spatial resolution so as to optimize acuity. The beta cell distribution and its systematic reflection in dendritic architecture predict acuity levels that apparently correlate well with actual visual performance across the cat's visual field.

Animals↗
PubMed1990

Topographic variations in W-cell input to cat superior colliculus.

Most of the retinal input to the cat's superior colliculus (SC) arises from W-cells of the contralateral eye and terminates just below the tectal surface. The goal of this study was to determine whether the strength of this input is uniform over the collicular map or, instead, exhibits topographic variations as has been reported for the retinotectal Y-cell projection (McIlwain and Lufkin 1976). Monosynaptic inputs from the principal W-cell projection mediate the late negative potential (LNP), a collicular field potential that can be evoked by shocks to the optic pathway. We assumed that the amplitude of the potential provided a measure of the strength of the W-cell input to the upper superficial gray layer. Using a fixed stimulus, we measured the maximal amplitude of the LNP at 90 topographically identified tectal sites in 5 cats. The amplitude of the LNP varied as much as 5-fold over the SC and was systematically related to the azimuthal position of the recording site. LNP amplitudes were consistently smallest in the representation of the area centralis and vertical meridian and largest in the representations of the contralateral hemifield periphery and the ipsilateral hemifield. There was little systematic variation in LNP amplitude as a function of elevation in the map. The observed variations did not result from non-uniform activation of retinal afferents or drift in properties of the recording electrodes, stimuli, or preparation. The results suggest that the principal W-cell input to the SC is weaker in the representation of the area centralis than elsewhere in the map.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1987

Isolated leukemia cutis--a case report.

A 67-year-old woman with acute myelomonocytic leukemia had a clinical course characterized by the initial appearance of leukemia cutis without bone marrow involvement. When marrow involvement subsequently occurred, induction chemotherapy cleared all manifestations of the illness. Shortly thereafter, while blood and bone marrow remained in remission, the skin lesions reappeared. The introduction of 6-thioguanine, as part of the maintenance treatment protocol, resulted in the rapid and permanent disappearance of the leukemic skin infiltrates.

Aged↗
PubMed1985

Bladder leiomyoma: a rare cause of pelvic pain.

Leiomyoma of the bladder is an unusual cause of persistent bladder or pelvic pain. Traditional modalities may enable the clinical to suspect the diagnosis, which should be confirmed by transurethral biopsy. Except in rare circumstances, the treatment of choice is a suprapubic abdominal approach for removal of the bladder tumor.

Adult↗
PubMed1984

The clinical significance of radiographically detected pulmonary neoplastic lesions in patients with head and neck cancer.

The histopathologic features of pulmonary lesions found in 36 patients with head and neck cancer ( HNC ) whose chest radiograms had abnormalities suggestive of a neoplasm were reviewed. Ten patients (28%) had benign lesions but cancer was diagnosed in 26 patients (72%) by lung biopsy or at autopsy. Second primary lung cancer was found in 19 (53%) and metastatic HNC in seven (19%) of the 36 patients examined. The second lung primaries occurred in seven (100%) patients with HNC in stage I or II and in 12 (63%) of those in stage III or IV. The histologic examination revealed squamous cell carcinoma of the lung in eight (42%) of 19 patients, small cell carcinoma in six (31.5%), adenocarcinoma in three (16%), and large-cell carcinoma in two (10.5%). These findings indicate that a prompt histologic examination of radiographically detected neoplastic pulmonary lesions in patients who have, or have had HNC is mandatory because a second primary cancer of the lung may be found and cured with early treatment. Furthermore, a substantial number of the patients in this retrospective analysis had small-cell carcinoma of the lung and could benefit from current therapeutic advances for this type of tumor.

Adenocarcinoma↗
PubMed1976

The external field intravascular electromagnetic flowmeter system as applied to standard arteriographic catheters and conscious humans.

New methodology, utilizing electromagnetic principles, has been developed for the measurement of regional vascular blood flow in intact animals and man. The flow sensor consists of a fine, insulated wire loop which has a small electrode on each side of the loop. This loop-probe, which is inserted like a guidewire through standard cardiac or angiographic catheters, springs open upon emerging from the catheter, and the electrodes are automatically applied to diametrically opposite sides of the inner vascular wall. This miniaturization of the flow sensor has been achieved by imposing the magnetic field which pervaces the artery from a coli located outside the body. As blood flows through the vessel across the magnetic field, the induced voltage across the blood column detected between the electrodes is proportional to the volume rate of blood flow. The loop-probe can be used simultaneously as an arterial diameter gauge. Means are described for achievement of a reliable, nonocclusive zero-flow baseline and flow calibration.

Angiography↗
PubMed1975

Pericardial effusion secondary to mucoepidermoid carcinoma of the parotid gland. A report of an unusual case.

This paper reports a unique case of malignant pericardial effusion secondary to metastatic mucoepidermoid carcinoma in a patient who previously had mucoepidermoid carcinoma of the parotid gland and subsequently was found to have a hypernephroma of the kidney. Its distinctive features warranted the diagnosis of mucoepidermoid carcinoma as the cause of the effusion, and excluded the more aggressive hypernephroma. Although pericardectomy was ultimately necessary, there was no evidence of viable malignancy in fluid specimens obtained after an initial course of radiation therapy or in the resected pericardium. This suggests that conservative treatment with local radiation therapy might be successful in future cases of pericardial effusion in this malignancy.

Adenocarcinoma↗
PubMed1975

Hemangioendothelioma of the testis.

A case of hemangioendothelioma of the testis is reported. Although the tumor has been reported in almost all organs and tissues, this is the first case involving the testis to be found in the literature. A distinction is made between the benign and the malignant form of the tumor. Hemangioendothelioma of the corpus cavernosum is discussed.

Adult↗