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Biomedical subjects

A Rothstein

Publications and source records attributed to A Rothstein.

At least 19 recordsLinked to original sources
PubMed1995

Cyclic AMP-related and cation-affected human platelet chloride transport regulation.

Cystic fibrosis has been characterized as a defect in the regulation of cyclic AMP-dependent transepithelial chloride transport. The activation of cyclic AMP-dependent protein kinase A by cyclic AMP occurs normally in cystic fibrosis cells, but they fail to transport chloride ions in response to protein kinase A stimulation. Defective chloride secretion and abnormal electrolyte transport occurs in several organs including the lung, sweat glands, intestine and pancreas. The present work was aimed at exploring whether the same or similar regulatory systems are functional in platelets, and if they are altered or deficient in individuals with cystic fibrosis. Chloride transport in platelets from normal subjects and from cystic fibrosis patients was measured by cell sizing techniques where chloride permeability is the limiting factor. In platelets from healthy volunteers, the chloride channel blocker, 5-nitro-2-(3-phenylpropylamino) benzoic acid, inhibits the transport in a dose-dependent manner. The preservation of chloride transport capability is shown to be dependent upon the presence of either Ca2+ or two divalent cation substitutes, Cd2+ or Cu2+. It is also shown that in normal subjects 0.1 mumol/l prostaglandin E1, which elevates cyclic AMP 6 times and abolishes platelet aggregation, significantly enhances the rate constant of the transport. Furthermore, in five out of nine cystic fibrosis patients studied, platelet chloride transport did not respond to stimulation by prostaglandin E1.

Adolescent↗
PubMed1995

Psychoanalytic technique and the creation of analysands: on beginning analysis with patients who are reluctant to pay the analyst's fee.

This paper discusses prospective analysands who are able but reluctant to pay analysts' fees. The author presents analytic data in which analysts decided to gratify their reluctant analysands by reducing their fees in order to facilitate the subsequent analysis of their reluctance. These examples are employed to discuss the general question of fee reduction.

Adult↗
PubMed1994

A perspective on doing a consultation and making the recommendation of analysis to a prospective analysand.

This paper explores the premise that the analyst's optimistic attitude toward the efficacy of analysis significantly enhances the possibility of success in helping prospective analysands accept the recommendation of analysis. This enthusiastic attitude reflects the author's opinion that analysis is the optimal treatment, the best form of psychotherapy for most adults. From this perspective, all patients seen in consultation are regarded as analyzable; this attitude is maintained until a prospective analysand proves he/she is unanalyzable in a trial of analysis. Analytic data from six consultations conducted from this perspective are presented and discussed.

Adult↗
PubMed1992

Monoclonal antibodies can protect L-asparaginase against inactivation by trypsin.

We show that a non-inhibitory monoclonal antibody (MAB) can be selected that provides substantial and sustained protection against proteolytic inactivation of L-asparaginase by trypsin. Of six non-inhibitory, high affinity, monoclonal antibodies to L-asparaginase, one afforded approximately 70% protection. Inactivation of L-asparaginase is associated with a single cleavage adjacent to lysine-29 that results in loss of an N-terminal fragment with a calculated MW of 2,647. The protective MAB prevented this trypsin cleavage. The products of gene fusions of "humanized" fragments of such antibodies and L-asparaginase could have increased clinical utility.

Amino Acid Sequence↗
PubMed1992

Volume-activated calcium uptake: its role in cell volume regulation of Madin-Darby canine kidney cells.

Immediately after osmotic swelling of Madin-Darby canine kidney (MDCK) cells, a transient (1-2 min) increase in Ca2+ influx and internal Ca2+ (Ca2+i) is observed. The normal Ca2+ influx appears to be mediated by the 3Na(+)-Ca2+ exchange system [Borle et al. Am. J. Physiol. 259 (Cell Physiol. 28): C19-C25, 1990], but the swelling-induced component is different in 1) Na+ dependence, 2) affinity for Ca2+, 3) inhibition by La3+, and 4) direction of net flux at low external Ca2+. Swelling appears to activate an uncoupled Ca2+ flow, perhaps through cation-nonspecific stretch-activated channels. The regulatory volume decrease (RVD) is dependent on the swelling-induced pulse of Ca2+ influx and associated rise in Ca2+i. Swelling also induces a biphasic change in membrane potential, a hyperpolarization followed by depolarization, reflecting sequential increases in K+ and Cl- permeabilities. The time dependence of the former corresponds closely with the transient peak in Ca2+i, but the latter does not. Ca2+i appears to have a direct activating effect on K+ channels but an indirect effect on Cl- channels, mediated via other Ca(2+)-triggered systems. The sequence of events following cell swelling appears to be transient increases in Ca2+ permeability, Ca2+ influx, Ca2+i, K+ permeability, followed by triggering of a mediating system that increases Cl- permeability. The net result is KCl, osmotic water loss, and volume adjustment.

Animals↗
PubMed1992

Observations on the utility of couples therapy conducted by a psychoanalyst--transference and countertransference in resistance to analysis.

This paper explores the premise that conviction concerning the therapeutic efficacy of psychoanalysis combined with a flexible attitude toward the structure of the analytic situation and the parameters of its techniques facilitates the acceptance of psychoanalysis in suitable cases as the treatment of choice. Clinical data from therapy with couples are presented in support of this premise.

Countertransference↗
PubMed1991

Stabilization of enzymes by their specific antibodies.

In nature, increased stability of enzymes has often been found to be associated with noncovalent protein-protein interactions. Specific antibodies should be suitable for this purpose. To test this hypothesis, we used a number of model enzymes, complexed them with their specific antibodies, and exposed them and the free enzymes to low and high temperature, lyophilization, oxidation, and alcohol. The retained activity of the antibody-complexed enzymes was substantially, and in some cases dramatically, higher. In general mechanistic terms, stabilization may have been accomplished either by noncovalent antibody crosslinking of discontinuous oligopeptide chains on the surface of the enzyme, thereby increasing resistance to unfolding of the enzyme, or by physical shielding by the antibodies of vulnerable sites on the surface of the enzyme.

Animals↗
PubMed1991

Actions of mercurials on cell volume regulation of dissociated MDCK cells.

The mercurial, p-chloromercuribenzoylsulfonate (PCMBS), blocks volume recovery of dissociated, osmotically swollen, Madin-Darby canine kidney cells (MDCK) and, at higher concentrations, induces substantial swelling. In the absence of Na+ the rate of volume recovery is, in contrast, substantially increased. PCMBS does not inhibit the "normal" volume-regulating pathways, K+ and Cl- conductances. Rather, its blocking action is due to substantial activation of Na+ and K+ permeabilities, especially the former. Consequently, the normal reshrinking mechanism, loss of KCl, is counterbalanced by PCMBS-induced gains of NaCl. In isotonic cells, PCMBS, at higher concentrations, induces cell swelling, indicating that Cl- permeability is also increased, a conclusion confirmed by direct measurement of 36Cl- fluxes. HgCl2 produces similar effects except that it is more potent and more rapid in its action. Activation of conductive ion permeabilities to Na+, K+, and Cl- are associated with appropriate changes in membrane potential. A small bumetanide-sensitive swelling component (Na(+)-Cl- cotransport) is activated by HgCl2 but not by PCMBS. Another effect is elevation of cytoplasmic Ca2+, apparently by mobilization from internal stores. Some of the functional sites (Na+ and K+) appear to be located externally, rapidly accessible to both HgCl2 and PCMBS, whereas others (Cl- and Ca2+) appear to be internal, rapidly accessible to the permeant HgCl2 but slowly to relatively impermeant PCMBS. In conclusion, the disturbances of volume regulation are largely due to the increases in conductive ion fluxes.

4-Chloromercuribenzenesulfonate↗
PubMed1991

Sadomasochism in the neuroses conceived of as a pathological compromise formation.

Masochistic phenomena in adults are discussed as derivatives of conscious and/or unconscious fantasies. These masochistic fantasies are always associated with conscious and/or unconscious narcissistic and sadistic fantasies. These fantasies, like all fantasies in adults, are conceived of as compromise formations. After a selected review of the literature, analytic data are presented to highlight the clinical advantages of a contemporary elaboration of the structural hypothesis for the understanding of sadomasochistic and sadonarcissistic phenomena.

Adult↗
PubMed1991

On some relationships of fantasies of perfection to the calamities of childhood.

In this paper narcissism conceived of as a fantasy of perfection is further redefined within an evolving structural model of psychic conflict. In pursuit of this goal a number of related propositions are explored. 1. A fantasy of perfection is best thought of as a compromise formation. 2. Fantasies of perfection have a development that is influenced, in part, by the development of the calamities of childhood. 3. Fantasies of perfection function as defences to diminish unpleasure associated with conflict. From this perspective a fantasy of perfection is a component of compromise formations. 4. The threat of the loss of the fantasy of perfection evokes anxiety while the sense the loss has occurred is associated with the experience of depressive affect. 5. Fantasies of perfection are important aspects of the compromise formations that constitute the superego. They are also important components of masochistic and narcissistic compromise formations characteristic of aspects of the ego. These compromise formations are intimately related to defensive identificatory relationships between the ego and superego. Analytic data are presented to demonstrate the value of these theoretical considerations.

Adult↗
PubMed1990

Antigen protection of monoclonal antibodies undergoing labelling.

The effectiveness of a methodology designed to protect the antigen binding capacity of monoclonal antibodies undergoing labelling with a number of reagents was examined. The antigen binding sites of monoclonal antibodies were protected by complexing them with their antigen. Chemical modification with 6 mM of the water soluble Bolton-Hunter reagent of site protected monoclonal antibodies to glucoamylase resulted in antibodies that could tolerate a four-fold increase in reagent incorporation, without any loss of antigen binding capacity. Iodination of these antibodies (modified under site protected conditions) yielded over 70% increase in radioactivity incorporated in the active antibody fraction, compared with the incorporation into unprotected antibodies. Site protected labeling was found to be effective in retaining the antigen binding capacity of monoclonal antibodies modified with all reagents tested with the exception of chloramine-T.

Animals↗
PubMed1990

Volume-activated K+ and Cl- pathways of dissociated epithelial cells (MDCK): role of Ca2+.

Osmotic swelling of dissociated Madin-Darby canine kidney (MDCK) cells in NaCl medium is followed by shrinking (regulatory volume decrease, or RVD) or in KCl medium by secondary swelling. The cation ionophore gramicidin has little effect on volumes of isotonic cells but accelerates volume-activated changes in either medium. Immediately after hypotonic exposure, the membrane becomes transiently hyperpolarized followed by depolarization. The depolarization phase is diminished by the anion transport inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). Swelling is also associated with an almost immediate increase in Ca2+ influx and elevation of cytoplasmic Ca2+ ([Ca2+]i) preceding RVD. In Ca2(+)-free medium, [Ca2+]i rapidly declines to a low level. Osmotic swelling, under these circumstances, is associated with a small transient increase in [Ca2+]i, but RVD or secondary swelling (in KCl) are minimal. Under these conditions, addition of gramicidin or the Ca2(+)-ionophore A23187 induces significant volume changes, although not as large as those found in the presence of Ca2+. Quinine inhibits RVD in the absence of gramicidin, but not in its presence; oligomycin C, DIDS, and trifluoperazine, on the other hand, inhibit in the presence of the ionophore. These findings suggest that in MDCK cells RVD involves activation of distinct conductive K+ and Cl- pathways which allow escape of KCl and osmotically obligated water and that activation of both pathways is associated with elevated [Ca2+]i derived largely from volume activation of a Ca2(+)-influx pathway.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1989

Net efflux of chloride from cell suspensions measured with a K+ electrode.

Under appropriate conditions (presence of cation ionophores) net KCl efflux measured with a K+ electrode can be used to estimate conductive Cl- fluxes, a sensitive procedure that allows continuous recording. The procedure was tested in human red cells by demonstrating effects of ionophores and of an anion transport inhibitor, and in dissociated MDCK cells by demonstration of cAMP and volume-activated Cl- fluxes.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1988

Na+/H+ exchange and aggregation of human platelets activated by ADP: the exchange is not required for aggregation.

Isolated human blood platelets, loaded with the pH-sensitive fluorescence dye 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein show cytoplasmic alkalinization upon stimulation with thrombin but acidification with ADP stimulation. In both cases a Na+/H+ exchange is activated. This can be revealed by the sensitivity of the induced pH changes to amiloride and to 5-N-(3-aminophenyl)amiloride (APA), known inhibitors of the Na+/H+ exchanger, and by a dependence on sodium in the external medium. ADP-induced platelet aggregation is not affected by omission of sodium from the external medium. Furthermore, aggregation is barely inhibited (less than 10%) by amiloride or APA at concentrations up to 50 microM while the Ki values in affecting the Na+/H+ exchange are 5.9 and 1.6 microM for amiloride and APA, respectively. Platelet aggregation is inhibited by amiloride or APA at concentrations higher than 50 microM, but this inhibition is apparently due to a secondary effect of the agents. It is concluded that platelet aggregation induced by ADP is not dependent on activation of Na+/H+ exchange.

Adenosine Diphosphate↗
PubMed1988

Activation of K+ and Cl- channels by Ca2+ and cyclic AMP in dissociated kidney epithelial (MDCK) cells.

In dissociated MDCK cells, activators of the cyclic AMP system cause depolarization detectable by changes in fluorescence of the membrane potential sensitive dye bisoxonol. Addition of forskolin (60 microM), vasopressin (2 microM), 8-bromo-cyclic AMP (0.5 mM) or 1-epinephrine (10 microM) depolarized the cells substantially in low Cl- (5 mM) but had little effect in high Cl- (140 mM) solution. These results are consistent with cyclic AMP activation of Cl- channels. The Ca2+-ionophore ionomycin (1 microM) produced a rapid hyperpolarization in low and high Cl- solutions, consistent with K+ channel opening. Using a clonal subline, MDCK-14, the magnitude of the ionomycin hyperpolarization was roughly proportional to the concomitant rise in [Ca2+]i as measured with the intracellular Ca2+ probe indo-I. Both l-epinephrine and isoproterenol appeared to activate the Cl- channels. However only l-epinephrine produced a [Ca2+]i rise and a transient hyperpolarization (due to K+ channel opening), which preceded the depolarization due to Cl- channel opening. The l-epinephrine-induced [Ca2+]i response of the heterogeneous MDCK cell population but not of the clonal subline MDCK-14 was inhibited by removal of extracellular Ca2+. In the latter only the slow secondary phase of the [Ca2+]i rise was affected by Ca2+ removal. It is concluded that l-epinephrine activates K+ and Cl- channels in a sequential manner in MDCK cells by Ca2+ and cAMP signals, presumably via alpha- and beta-adrenergic receptors located on the same cell.

Animals↗