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Biomedical subjects

J Port

Publications and source records attributed to J Port.

At least 19 recordsLinked to original sources
PubMed2000

Different generators in human temporal-parasylvian cortex account for subdural laser-evoked potentials, auditory-evoked potentials, and event-related potentials.

In order to localize cortical areas mediating pain we now report subdural cortical potentials evoked by auditory stimulation (auditory-evoked potentials - AEPs) and by cutaneous stimulation with a laser (laser-evoked potentials - LEPs). Stimulation with the laser evokes a pure pain sensation by selective activation of nociceptors. LEPs were maximal over the inferior aspect of the central sulcus and had the same polarity on either side of the sylvian fissure. AEPs were maximal posterior to the LEP maximum and had opposite polarity on opposite sides of the sylvian fissure, consistent with the location of a known generator in the temporal operculum. Auditory P3 (event-related) potentials were maximal over the temporal base. These findings demonstrate that the LEP generator is not in secondary somatosensory cortex on the parietal operculum and is different from the P3 generator.

Adult↗
PubMed1999

Lymphoepithelial cyst (LEC) of the pancreas: cytomorphology and differential diagnosis on fine-needle aspiration (FNA).

Lymphoepithelial cyst (LEC) of the pancreas is an extremely rare benign entity. We describe the cytopathologic findings of such a lesion in a 49-yr-old woman who was examined for epigastric pain. A trans-esophageal ultrasound-guided fine-needle aspiration of a pancreatic mass disclosed an intimate mixture of squamous epithelial cells and small, mature lymphocytes in a background of keratinaceous debris, anucleate squames, and multinucleated histiocytes. On histopathologic examination, a subsequent resection showed a multiloculated cystic lesion with a stratified squamous epithelial lining surrounded by well-formed lymphoid tissue, suggestive of LEC. The differential diagnosis includes other pancreatic pseudocysts, dermoid cyst, mucinous cystic neoplasms, adenosquamous carcinoma, and metastatic squamous cell carcinoma.

Biopsy, Needle↗
PubMed1998

Intraabdominal desmoplastic small round cell tumor: cytopathologic findings in two cases.

Intraabdominal desmoplastic small round cell tumor (DSRCT) is an extremely rare entity. This study describes fine-needle aspiration, ascitic fluid, and touch imprint cytomorphology of DSRCT in 2 patients with extensive abdomino-pelvic disease. Cytopathologic features were unique and showed good morphologic correlation with subsequent histology of the resected tumor. Immunocytochemical profile and differential diagnosis with other small round cell tumors in this age group are also discussed.

Abdominal Neoplasms↗
PubMed1996

Regulation of the mRNA-binding protein AUF1 by activation of the beta-adrenergic receptor signal transduction pathway.

In both cell culture based model systems and in the failing human heart, beta-adrenergic receptors ( beta-AR) undergo agonist-mediated down-regulation. This decrease correlates closely with down-regulation of its mRNA, an effect regulated in part by changes in mRNA stability. Regulation of mRNA stability has been associated with mRNA-binding proteins that recognize A + U-rich elements within the 3'-untranslated regions of many mRNAs encoding proto-oncogene and cytokine mRNAs. We demonstrate here that the mRNA-binding protein, AUF1, is present in both human heart and in hamster DDT1-MF2 smooth muscle cells and that its abundance is regulated by beta-AR agonist stimulation. In human heart, AUF1 mRNA and protein was significantly increased in individuals with myocardial failure, a condition associated with increases in the beta-adrenergic receptor agonist norepinephrine. In the same hearts, there was a significant decrease (approximately 50%) in the abundance of beta1-AR mRNA and protein. In DDT1-MF2 cells, where agonist-mediated destabilization of beta2-AR mRNA was first described, exposure to beta-AR agonist resulted in a significant increase in AUF1 mRNA and protein (approximately 100%). Conversely, agonist exposure significantly decreased (approximately 40%) beta2-adrenergic receptor mRNA abundance. Last, we demonstrate that AUF1 can be immunoprecipitated from polysome-derived proteins following UV cross-linking to the 3'-untranslated region of the human beta1-AR mRNA and that purified, recombinant p37AUF1 protein also binds to beta1-AR 3'-untranslated region mRNA.

Base Sequence↗
PubMed1995

Preparation of an exogenous fibrin clot.

Exogenous fibrin clot has been proposed to promote the healing of meniscal tears in areas of compromised vascularity. We present a method to reproducibly prepare a tightly wound exogenous fibrin clot using 5 to 10 mL of blood obtained by sterile venipuncture. The technique produces a clot of increased consistency and high fibrin content that is adaptable in preparation as a longer, thinner clot or a shorter, thicker clot. Clots prepared in this manner will hold suture or can be morselized for extrusion through a syringe.

Animals↗
PubMed1994

A theory of cooperativity modulation in neural networks as an important parameter of CNS catecholamine function and induction of psychopathology.

Recent research in computational neuroscience has suggested that psychosis associated with disturbed catecholamine neurotransmission may result from disturbances in the gain parameters of neural networks that these same secondary neurotransmitters are thought to control. We propose a mathematical model based upon cooperativity theory used in thermodynamics to explain how the gain parameter that momentarily increases the effect upon the post-synaptic cell of a given weighted connection from the presynaptic cell could be instantiated in the fluctuating electrical conductance of the dendrite of a neuron without requiring extensive ion transport or utilization of the ATP energy cycle. More specifically we propose that catecholamine neurotransmission serves to maintain the dendrite in a cooperative state with regard to changes in electrical conductance due to impulse traffic alone. In this way we supply the neuron with an activity driven gain parameter that not only increases volume of neuronal output at very low energy cost but that also upscales cooperative effects at the mechanico-chemical level of the dendrite to the network level itself. An important implication of this model is that two extreme states for dendritic electrical conductance will occur if cooperativity is lost at the level of catecholamine depletion or excess due to drug effects. These are the AND gate effect in which dendritic conductance is so low that the neuron requires extensive synaptic activity in order to output significantly. We correlate this state with negative symptoms in schizophrenia and psychomotor retardation in depression as well as the rigidity in Parkinsonism. The other extreme is represented by the OR gated dendrite in which conductance is so high that even noisy input to the dendrite will lead to significant nerve cell output. We correlate this condition with the positive symptoms of schizophrenia, the agitated features of psychotic depression and the tremors of Parkinsonism.

Animals↗
PubMed1991

Granulomatous hepatitis in cat-scratch disease. Ultrasound and CT observations.

A male two year old was admitted to the hospital with a one month history of fever. The physical examination was unrevealing. Abdominal ultrasound revealed multiple, circumscribed regions of low attenuation in the liver and a parapancreatic mass. Laparotomy and biopsy revealed multiple nodules in the liver. The histopathologic findings indicated the child had cat-scratch disease, which resolved with administration of gentamycin sulfate.

Cat-Scratch Disease↗
PubMed1980

Faculty attitudes toward the use of audiovisuals in continuing education.

A study was undertaken in planning for a project involving library support for formal continuing education programs. A questionnaire survey assessed faculty attitudes toward continuing education activities, self-instructional AV programs for continuing education, and self-instructional AV programs for undergraduate medical education. Actual use of AV programs in both undergraduate and postgraduate classroom teaching was also investigated. The results indicated generally positive attitudes regarding a high level of classroom use of AV programs, but little assignment of audiovisuals for self-instruction.

Attitude↗
PubMed1980

Megamitochondria in hepatic and renal disease.

This study was undertaken to determine the incidence and significance of enlarged mitochondria ("swollen" or "giant") in individuals with various forms of liver disease and in patients with idiopathic nephrotic syndrome. Enlarged mitochondria were observed in 20/30 liver biopsies and in 24/45 renal biopsies. They were present in hepatocytes but not in the bile duct epithelial cells and in the epithelial cells of both proximal and distal convoluted tubules of the nephron. The available experimental data indicate that enlargement of this organelle is associated with inhibition of mitochondrial respiration and uncoupling of oxidative phosphorylation. Mitochondrial swelling follows almost universally every type of cell injury but megamitochondria with intramatrical crystals appear only under certain conditions. No explanation is available for their common presence in various forms of human disease.

Adolescent↗
PubMed1978

Heavy-metal and antibiotic resistance in the bacterial flora of sediments of New York Bight.

The New York Bight extends seaward some 80 to 100 miles (ca. 129 to 161 km) from the Long Island and New Jersey shorelines to the edge of the continental shelf. Over 14 x 10(6) m(3) of sewage sludge, dredge spoils, acid wastes, and cellar dirt are discharged into this area each year. Large populations of Bacillus sp. resistant to 20 mug of mercury per ml were observed in Bight sediments contaminated by these wastes. Resistant Bacillus populations were much greater in sediments containing high concentrations of Hg and other heavy metals than in sediments from areas further offshore where dumping has never been practiced and where heavy-metal concentrations were found to be low. Ampicillin resistance due mainly to beta-lactamase production was significantly (P < 0.001) more frequent in Bacillus strains from sediments near the sewage sludge dump site than in similar Bacillus populations from control sediments. Bacillus strains with combined ampicillin and Hg resistances were almost six times as frequent at the sludge dump site as in control sediments. This observation suggests that genes for Hg resistance and beta-lactamase production are simultaneously selected for in Bacillus and that heavy-metal contamination of an ecosystem can result in a selection pressure for antibiotic resistance in bacteria in that system. Also, Hg resistance was frequently linked with other heavy-metal resistances and, in a substantial proportion of Bacillus strains, involved reduction to volatile metallic Hg (Hg degrees ).

Anti-Bacterial Agents↗
PubMed1978

[Familical cleft foot--a clinical study over 4 generations (author's transl)].

Within this paper a family is being described in which foot deformities are shown over four generations. During two generations cleft foot is found as well as a syndaktylism. The cases are demonstrated clinically, by photographs and also by X-ray. The question of inheritance is being discussed in comparison with the existing literature, also taking into account the coexistence of cleft foot and syndaktylism.

Abnormalities, Multiple↗