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Biomedical subjects

B Cohen

Publications and source records attributed to B Cohen.

At least 289 records · Page 16Linked to original sources
PubMed1990

Characterization of pp85, a target of oncogenes and growth factor receptors.

An 85,000-molecular-weight polypeptide (85K polypeptide) has previously been identified as a common substrate for tyrosine phosphorylation upon polyomavirus middle T transformation or upon platelet-derived growth factor stimulation of 3T3 cells. In each case, pp85 has an associated phosphatidylinositol kinase activity. The tissue distribution of pp85 was determined by middle T blotting experiments; the highest levels were found in brain, lung, and spleen tissues. High-resolution examination of 85K by isoelectric focusing demonstrated that there are at least 10 different forms. These were resolved into two families, 85K and 86K; the ratio of the two families changed in different cells. Similar forms were found for pp85 associated with pp60v-src. Individual species within each family differed by phosphorylation. Analysis of pp85 and pp86 by immunoprecipitation with anti-phosphotyrosine antibody showed increasing phosphorylation in response to middle T or pp60v-src transformation. The association of middle T with pp85 and pp60c-src was examined in pulse-chase experiments. Association of middle T with pp60c-src was slow and was accompanied by progressive modification of middle T. pp85 formed a dissociable complex with middle T within 2.5 min.

1-Phosphatidylinositol 4-Kinase↗
PubMed1990

Contribution of the nucleus of the optic tract to optokinetic nystagmus and optokinetic afternystagmus in the monkey: clinical implications.

1. The role of the pretectal NOT and the DTN in producing horizontal OKN and OKAN were studied using electrical stimulation and lesions. Positive stimulation sites lay in NOT, DTN, and in a fiber bundle in the pulvinar that is presumably a cortical input to NOT. 2. When the region of NOT was electrically stimulated in darkness, horizontal nystagmus was evoked with ipsilateral slow phases. Eye velocity rose slowly to a steady-state level and was followed by afternystagmus at the end of stimulation. The time constant of rise of stimulus-induced nystagmus was similar to the slow rise of slow-phase eye velocity during OKN. The saturation velocity of the induced nystagmus and the falling time constant of the stimulus afternystagmus were the same as those of OKAN. This suggests that electrical stimulation of NOT and DTN had elicited the slow component of OKN, i.e., that component produced by the velocity storage mechanism in the vestibular system. 3. Consistent with this postulate, activity induced by NOT stimulation could enhance, prolong, or block the slow component of OKN and OKAN depending on whether slow phases were to the same or opposite side. Stimulus-induced activity also interacted with vestibular nystagmus as would OKN and OKAN. 4. Unilateral lesions of NOT and DTN caused a loss of OKAN and the slow rise in OKN to the ipsilateral side. Steady-state velocities of OKN were reduced. The initial jump of OKN slow-phase velocity was the same or somewhat less after lesions but was not lost. 5. Partial lesions of a fiber bundle in the lateral pulvinar caused a transient change in OKN and OKAN, consistent with the idea that it carries activity for the slow component from the cortex to NOT. A lesion of the MRF, just rostral to the superior colliculus, caused a transient loss of the rapid component of OKN. This region appears to carry activity responsible for the initial jump in slow-phase velocity at the onset of stimulation. 6. We conclude that: (a) NOT and probably DTN lie in the indirect pathway that produces the slow component of horizontal OKN and OKAN to the ipsilateral side in the rhesus monkey. This pathway activates the velocity storage mechanism in the vestibular nuclei. (b) At the level of NOT, the pathway responsible for the slow component of OKN and OKAN is anatomically distinct from the pathway responsible for rapid changes in eye velocity at the onset of OKN.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Porcelain laminate retained fixed bridge: two case reports.

With the recent introduction of new high strength dental porcelains, laminate veneers and all porcelain crowns, inlay and onlay restorations are becoming increasingly popular. Because these materials possess such high strength and hardness, it is possible, in certain carefully selected clinical situations, to construct short-span anterior fixed bridges by incorporating a pontic with two modified laminate retainers. Two clinical cases are presented to illustrate how this technique can be successfully utilized to achieve an excellent esthetic and functional result in a truly conservative manner.

Adult↗
PubMed1990

Topical cyclosporine administration in rabbits.

Cyclosporine (CyA) is a potent immunosuppressant, but possesses toxicities which prohibit its unrestricted dosing in patients. The topical administration of CyA could serve to localize the immunosuppressive effect, or could serve as an administration route for patients who cannot tolerate the oral route of administration. We evaluated the potential for transdermal delivery of cyclosporine in rabbits. We sensitized six rabbits to dinitrochlorobenzene (DNCB), treated them topically with either 100 mg CyA or the vehicle, and repeated the DNCB skin testing at 15 and 28 days at the site of administration and at a distal site. In the CyA treated rabbits, significant increases in the suppression of the reaction to DNCB were observed from the control to the 15 day test, and from the 15 to the 28 day testing. Significant differences were also observed between reaction to DNCB at the site of CyA administration and at the distal site. While blood concentrations demonstrated slow and variable absorption of the topically administered CyA, concentrations greater than 1000 ng/ml were frequently observed in blood. We conclude that the local versus a systemic dermatologic effect of CyA can be achieved, and that high blood concentrations are present after topical CyA administration in this model.

Administration, Topical↗
PubMed1989

Enhancer functions and in vitro protein binding of native and mutated interferon-responsive sequences.

Mutants of the Interferon responsive sequence (IRS) of the mouse and human (2'-5') A synthetase (moE-IRS and hE-IRS) were tested for their Interferon (IFN)-inducible enhancer functions and for protein binding in vitro. Two complexes R1 and R3, were formed specifically with the hE-IRS. R3 migrated much faster and was about ten times more abundant than R1. R1 and R3 are increased about 2-fold in IFN-treated HeLa extracts relatively to extracts from non-treated cells. R1 and R3 seem to involve the same DNA sequence in the probe since they react identically to competitors. Two proteins of 69 and 46 kDa form the IRS specific complexes as revealed by UV cross-linking. Identical DNA probes bearing either the hE-IRS or moE-IRS form complexes of different characteristics with nuclear proteins, suggesting that the two IRS variants are the targets of binding of different proteins or of different protein complexes.

Animals↗
PubMed1989

Cortisol and sodium lactate-induced panic.

Sodium lactate infusions induce panic attacks in patients with panic disorder, but not in normal controls, by an unknown mechanism. We studied the plasma cortisol response to infusion of 0.5 mol/L of sodium lactate in 103 patients with panic disorder or agoraphobia with panic attacks, and 32 normal controls. Baseline cortisol levels did not distinguish early panickers from non-panickers and controls, but late panickers had significantly elevated baseline cortisol levels. In addition, a higher percentage of late panickers manifested an increase in cortisol during the baseline period compared with the other groups. Despite the fact that late panickers manifested elevated baseline cortisol levels, early panickers had significantly greater somatic distress as measured by the Acute Panic inventory. There was no increase in cortisol with lactate-induced panic, and cortisol levels fell significantly during the lactate infusion in all groups. Cortisol elevation occurred with moderate anxiety but not with severe panic anxiety. These results suggest different pathophysiologic mechanisms of early and late panic, and differences between anticipatory anxiety and panic anxiety.

Adult↗
PubMed1989

Restoration of fixed partial dentures with fractured porcelain veneers using an overcasting.

Fracture and loss of the porcelain veneer of a fixed partial denture is troublesome. Dentists have frequently used overcastings to avoid removal of the restoration. However, development of proximal resistance and retention form for the preparation creates a problem because reduction of the connector causes fracture. Nevertheless, a box-type occlusal cavity form in the central portion of the preparation will enhance the stability of the restoration without encroachment on the connectors. This design is more applicable to endodontically treated teeth.

Cementation↗
PubMed1989

Prolactin and sodium lactate-induced panic.

Sodium lactate infusions reliably induce panic attacks in panic disorder patients but not in normal controls, but the mechanism underlying this response is unknown. We studied the plasma prolactin response to infusion of 0.5 molar sodium lactate in 38 patients with panic disorder or agoraphobia with panic attacks, and 16 normal controls. As expected, baseline plasma prolactin was significantly higher in female subjects than in male subjects. However, the males who experienced lactate-induced panic had significantly elevated baseline prolactin levels compared to male nonpanickers and controls. Prolactin levels increased in all groups during lactate infusion, which may reflect osmotic effects, but were blunted in the late panickers compared to nonpanickers and controls. The elevated baseline prolactin for male panickers supports a relationship between prolactin and anticipatory anxiety. The blunted prolactin response for late panickers suggests a net diminution, rather than a sensitization, of prolactin response in panic anxiety.

Adult↗
PubMed1989

A chart review study of late-onset and early-onset schizophrenia.

This chart review study compared 54 schizophrenic patients with onset of illness after age 45 years to 54 young and 22 elderly patients with early-onset schizophrenia (before age 45). The index group was more likely to have visual, tactile, and olfactory hallucinations; a greater number of different types of hallucinations; persecutory delusions; and premorbid schizoid personality traits, and was less likely to have thought disorder and affective flattening, than was either comparison group. Among the two elderly groups, index patients had more auditory and visual sensory impairment. Nearly half (48.1%) of the index patients responded to neuroleptic treatment with complete remission.

Adolescent↗