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Biomedical subjects

J Lerner

Publications and source records attributed to J Lerner.

At least 19 recordsLinked to original sources
PubMed2000

Adenoviral vector containing wild-type p16 suppresses prostate cancer growth and prolongs survival by inducing cell senescence.

It is estimated that there will be >184,500 new cases of prostate cancer and 42,000 prostate cancer deaths in the United States this year. In the majority of patients diagnosed with prostate cancer, the disease will be too advanced for cure with standard medical treatment. New therapeutic strategies against advanced prostate cancer are desperately needed. As alterations in tumor-suppressor gene p16 are common in prostate cancer, one novel approach is gene therapy using a replication-deficient, E1/E3-deleted adenovirus type 5 containing a p16 under the control of a truncated Rous sarcoma virus promoter (AdRSVp16). In vitro, PC-3 cells that had been stably transfected with p16 expression vector under the control of an inducible promoter had a 70% reduction in cell number compared with the parental and control vector-transfected PC-3 cells. Similarly, AdRSVp16 significantly inhibited the growth of PPC-1 and PC-3 prostate cancer cells in culture. Furthermore, PPC-1 tumors grown in nude mice treated by a single injection of AdRSVp16 had a marked reduction in tumor size compared with untreated control-treated or viral control-treated PPC-1 tumors. Animals bearing tumors treated with AdRSVp16 also had longer survival. Adenovirally mediated expression of transgene was detected in xenograft tumors for at least 2 weeks. Taken together, these results suggest that AdRSVp16 should be considered for prostate cancer gene therapy in human clinical trials.

Adenoviridae↗
PubMed1999

Differentiating anxious and depressive self-statements in youth: factor structure of the Negative Affect Self-Statement Questionnaire among youth referred to an anxiety disorders clinic.

Conducted a factor analysis on the items from the Negative Affect Self-Statement Questionnaire (NASSQ; Ronan, Kendall, & Rowe, 1994). This analysis yielded 4 factors (Depressive Self-Statements, Anxiety/Somatic Self-Statements, Negative Affect Self-Statements, and Positive Affect Self-Statements) broadly consistent with both the content-specificity hypothesis (Beck & Clark, 1988) and L. A. Clark and Watson's (1991b) tripartite model of anxiety and depression. The association between children's self-talk and measures of trait anxiety and depression was also examined. Self-statements with content theoretically specific to depression were the best predictors of self-reported depressive symptoms, but the results were less clear for trait anxiety. Overall, these results provide evidence for the discriminability of anxious and depressive self-talk in youth and for the utility of the NASSQ as a cognitive assessment instrument.

Adolescent↗
PubMed1994

Transvaginal sonographic characterization combined with cytologic evaluation in the diagnosis of ovarian and adnexal cysts.

A transvaginal sonographic (TVS) scoring system using morphologic features has been developed at our institution to maximize discrimination between benign and malignant ovarian and adnexal cysts. Low (4-7) or intermediate (8-9) scores have been found to correlate with benignity, hence TVS-guided or laparoscopically directed needle aspiration of low-scoring lesions may safely be performed. High-scoring lesions (10-14) are often malignant, therefore in situ needle aspiration of such lesions is not recommended. The aim of our study was to correlate the results of TVS characterization of ovarian and adnexal cysts with the aspiration cytologic evaluation. Twenty-three of the 43 cysts studied were aspirated in situ from the patient; 20 were aspirated from resected surgical specimens. Thirty-six benign cysts had TVS scores ranging from 4 to 12, with a median score of 7. All 25 cysts that were benign by TVS and/or histology were also cytologically benign as well as an additional 11 cysts that were not resected (TVS scores: 4 to 9). Seven cytologically and histologically malignant cysts had high TVS scores (TVS scores 10-14; median = 12). The combination of TVS and needle aspiration cytology is valuable, particularly in the diagnosis of cysts having low or intermediate TVS scores and benign cytology. Aspiration of cysts or masses with high TVS scores is not recommended. This combined evaluation may allow a more limited surgical approach, such as operative laparoscopy, or, in some cases, obviate the need for operative treatment altogether.

Adnexal Diseases↗
PubMed1994

Severe diarrhea associated with Arcobacter butzleri.

Two patients with chronic disease (diabetes mellitus type I, hyperuricemia and alcohol abuse, respectively) were hospitalized with persistent diarrhea and severe abdominal cramps. Using routine methods, the only pathogen isolated in stool specimens was Arcobacter butzleri. In both cases acute symptoms subsided quickly after antibiotic therapy. After termination of antibiotic treatment, Arcobacter butzleri could no longer be detected in stool specimens. Although very little is known about the clinical significance of Arcobacter butzleri infections in humans, it is highly likely that in both cases Arcobacter butzleri played a major causative role in acute disease.

Diarrhea↗
PubMed1991

Human papillomavirus segregation patterns in genital and nongenital warts in prepubertal children and adults.

This study compared the segregation patterns of human papillomavirus (HPV) in genital and nongenital warts in prepubertal children and adults. HPV 2 was detected in most nongenital warts in children and adults, whereas neither HPV 6 or 11 was detected at nongenital sites in either group with the use of in situ or Southern blot hybridization analyses. Of nine genital tract lesions in children. HPV 2 was detected in two and HPV 6 or 11 in six. More than 90% of cases of regional tract condylomata in adults contained HPV 6 or 11. HPV 2 was not detected in any of 99 genital tract lesions in adults. It is concluded that HPV 6/11 cannot proliferate at nongenital cutaneous sites and HPV 2 can proliferate in the genital tract of children but not adults. Thus, the detection of HPV 6 or 11 in a genital wart in a child implies, assuming cutaneous transmission, infection from a genital site, whereas the detection of HPV 2 presumes nongenital transmission.

Adult↗
PubMed1990

Unresponsiveness of forearm hemodynamics to omega-3 polyunsaturated fatty acids and aspirin.

Prostaglandin synthesis has been reported to change with aspirin ingestion via cyclooxygenase enzyme inhibition and with marine oil supplementation via an increase in the metabolism of 3-series eicosanoids. This study investigated the effects of pharmacological manipulations of prostaglandin metabolism on forearm hemodynamics and blood pressure. The agents studied were omega-3 fatty acids and aspirin. In the omega-3 fatty acid study, two groups of normal volunteers (N = 10/group) supplemented their diets with either marine oil capsules or placebo. Hemodynamic variables (Mercury-in-Silastic forearm plethysmography) were measured initially and weekly for 4 weeks. There were no significant differences between the two groups in blood pressure, forearm blood flow, venous capacitance, or forearm vascular resistance. Parallel changes occurred for forearm blood flow and venous capacitance. Six normal volunteers took daily dosages of aspirin, increasing from 162 to 2600 mg. Hemodynamic measurements, ADP-induced platelet aggregation, and serum salicylate levels were obtained daily. Maximum inhibition of platelet aggregation occurred after 162 mg. (serum salicylate = 17.7 +/- 6.4 mg/l). Though serum salicylate levels rose to 165.0 +/- 20.0 mg/l, no significant changes occurred in blood pressure or forearm blood flow. Even at aspirin levels 16-fold greater than those required to impair platelet aggregation, the changes in forearm vascular resistance were not found to be significant. These results suggest that under resting conditions in normotensive males, neither pharmacological inhibition nor stimulation of vascular prostaglandin metabolism alters forearm vascular resistance or arterial blood pressure.

Adult↗
PubMed1989

Choline transport specificity in animal cells and tissues.

1. Beta carbolines inhibit choline transport in rat brain. 2. The aziridinium ring on the nitrogen of mustard analogs of choline causes irreversible binding to the carrier in rat brain. 3. The uptake system in rat brain is stereoselective, requires a quaternary nitrogen, and prefers analogs with a nitrogen-oxygen distance of about 3.26 A. 4. In mouse brain troxonium derivatives inhibit choline transport. 5. In cuttlefish optic lobes and torpedo electric organ pyrene derivatives potently inhibit choline transport. 6. In guinea pig placenta, the affinity of the choline carrier remains high even when this molecule lacks one or two methyl groups.

Animals↗
PubMed1987

Acidic amino acid transport in animal cells and tissues.

1. The occurrence and characterization of acidic amino acid transport in the plasma membrane of a variety of cells and tissues of a number of organisms is reviewed. 2. Several cell types, especially in brain, possess both high- and low-affinity transport systems for acidic amino acids. 3. High-affinity systems in brain may function to remove neurotransmitter amino acid from the extracellular environment. 4. Many cell systems for acidic amino acid transport are energized by an inwardly directed Na+ gradient. Moreover, certain cell types, such as rat brain neurons, human placental trophoblast and rabbit and rat kidney cortex epithelium, respond to an outwardly directed K+ gradient as an additional source of energization. This simultaneous action may account for the high accumulation ratios seen with acidic amino acids. 5. Rabbit kidney has been found to have a glutamate-H+ co-transport system which is subject to stimulation by protons in the medium. 6. Acidic amino acid transport in rat brain neurons occurs with a stoichiometric coupling of 1 mol of amino acid to 2 mol of Na+. For rabbit intestine, one Na+ is predicted to migrate for each mol of amino acid. 7. Uptake in rat kidney cortex and in high-K+ dog erythrocytes is electrogenic. However, uptake in rabbit and newt kidney and in rat and rabbit intestine is electroneutral. 8. Na+-independent acidic amino acid transport systems have been described in the mouse lymphocyte, the human fibroblast, the mouse Ehrlich cell and in rat hepatoma cells. 9. In a number of cell systems, D-acidic amino acids have substantial affinity for transport; D-glutamate, in a number of systems, however, appears to have little reactivity. 10. Acidic amino acid transport in some cell systems appears to occur via the "classical" routes (Christensen, Adv. Enzymol. Relat. Areas Mol. Biol. 49, 41-101, 1979). For example, uptake in the Ehrlich cell is partitioned between the Na+-dependent A system (which transports a wide spectrum of neutral amino acids), the Na+-dependent ASC system (which transports alanine, serine, threonine, homoserine, etc.), and the Na+-independent L system (which shows reactivity centering around neutral amino acids such as leucine and phenylalanine). Also, a minor component of uptake in mouse lymphocytes occurs by a route resembling the A system. 11. Human fibroblasts possess a Na+-independent adaptive transport system for cystine and glutamate that is enhanced in activity by cystine starvation.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗
PubMed1986

Comparative aspects of the apparent Michaelis constant for neutral amino acid transport in several animal tissues.

The apparent Michaelis constant, Km, for transport of a number of neutral amino acids has been compared between intestine, heart, brain and erythrocytes among a variety of animals using values available in the literature. Neutral amino acids with side chains containing 3, 4, 7 and 9 carbon atoms had approximately equal mean Km values when tested for intestinal transport among a variety of species; alanine appeared to have a mean Km value that was larger than those found for the first group, and glycine had a significantly greater mean Km than all of the other compounds tested. Km values for phenylalanine and tryptophan measured in rat heart were found to be close to the means measured for these substrates in intestine. The mean Km values measured in mammalian brain for each of the neutral amino acid substrates were found not be significantly different from each other. When the means of Km values for the neutral amino acids tested were compared between intestine and brain, only the glycine means were shown to differ significantly between the organs. Based on data for several mammalian species, brain appears to have a greater average apparent affinity for glycine than does intestine. In the human erythrocytes and in a few other mammalian species, Km values for all neutral amino acids tested with exception of glycine were found to be similar in magnitude to each other and to the Km averages of neutral amino acids found in intestine for the series containing 3-9 carbon atoms. The Km value for glycine in the human erythrocyte was noted to be substantially lower in value than the averages for glycine in brain or intestine. Avian red blood cells appear to have high apparent affinity for neutral amino acid transport when compared with red cells of several mammalian species.

Amino Acids↗
PubMed1985

Effectors of amino acid transport processes in animal cell membranes.

Various effectors, which act upon ion gradients, protein synthesis, membrane components or cellular functional groups, have been employed to provide insights into the nature of amino acid-membrane transport processes in animal cells. Such effectors, for example, include ions, hormones, metabolites and various organic reagents and their judicious use has allowed the following list of conclusions. Sodium ion has been found to stimulate amino acid transport in a wide variety of cell systems, although depending on the tissue and/or substrate, this ion may have no effect on such transport, or even inhibit it. Amino acid transport can be stimulated in some cell systems by other ions such as K+, Li+, H+ or Cl-. Both H+ and K+ have been found to be inhibitory in other systems. Amino acid transport is dependent in many cell systems upon an inwardly directed Na+ gradient and is stimulated by a membrane potential (negative cell interior). In some cell systems an inwardly directed Cl- and H+ gradient or an outwardly directed K+ gradient can energize transport. Structurally dissimilar effectors such as ouabain, Clostridium enterotoxin, aspirin and amiloride inhibit amino acid transport presumably through dissipation of the Na+ gradient. Inhibition by certain sugars or metabolic intermediates of the tricarboxylic acid cycle may compete with the substrate for the energy of the Na+ gradient or interact with the substrate at the carrier level either allosterically or at a common site. Stimulation of transport by other sugars or intermediates may result from their catabolism to furnish energy for transport. Insulin and glucagon stimulate transport of amino acids in a variety of cell systems by a mechanism which involves protein synthesis. Microtubules may be involved in the regulation of transport by insulin or glucagon. Some reports also suggest that insulin has a direct effect on membranes. In addition, a number of growth hormones and factors have stimulatory effects on amino acid transport which are also mediated by protein synthesis. Steroid hormones have been noted to enhance or diminish transport of amino acids depending on the nature of the hormone. These agents appear to function at the level of protein synthesis. While stimulation may involve increased carrier synthesis, inhibition probably involves synthesis of a labile protein which either decreases the rate of synthesis or increases the rate of degradation of a component of the transport system.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗
PubMed1984

Cell membrane amino acid transport processes in the domestic fowl (Gallus domesticus).

Intestinal absorption of amino acids in the chicken occurs by way of processes which are concentrative, Na+-dependent and dependent upon metabolic energy in the form of ATP. Intestinal transport is carrier-mediated, subject to exchange transport (trans-membrane effects) and is inhibitable by sugars, reagents which inactivate sulfhydryl groups, potassium ion, and by deoxpyridoxine, an anti-vitamin B6 agent. It is stimulated by phlorizin, a potent inhibitor of sugar transport, and in Na+-leached tissue by modifiers of tissue cyclic AMP levels, e.g. theophylline, histamine, carbachol and secretin. Separate transport sites with broad, overlapping specificities function in the intestinal absorption of the various classes of common amino acids. A simple model for these sites includes one for leucine and other neutral amino acids, one for proline, beta-alanine and related imino and amino acids, one for basic amino acids, and one for acidic amino acids. Absorption of amino acids appears to be widespread in occurrence in the digestive tract of the domestic fowl; transport has been reported to be present in the crop, gizzard, proventriculus, small intestine and in the colon. By the end of the first week of life post-hatch, the caecum loses its ability to transport. Similarly, the yolk sac loses its ability by the second day post-hatch. Intestinal transport was noted before hatch and was found to be maximal immediately post-hatch. A requirement for Ca2+ appears to be lost after the first week of life post-hatch. The cationic amino acids appear to be reabsorbed by a common mechanism in the kidney. Transport rates of leucine measured in the intestine or in the erythrocyte were found to cluster about discrete values when many individual chickens were surveyed; such patterns may be an expression of gene differences between individuals. Two lines of chickens have been developed, one high and the other low uptake, through selective breeding based on the ability of individual birds to absorb leucine in erythrocytes. High leucine absorbing chickens were found to be more effective in absorbing lysine and glycine, were more effectively stimulated by Na+, had greater erythrocyte Na+, K+-ATPase activity, and their erythrocytes contained about 20% less Na+ than low line erythrocytes. The underlying genetic difference between these lines may reside at the level of the Na+, K+-ATPase and (or) with a regulatory gene determining carrier copies. Amino acid transport in erythrocytes was noted to be highest in pre-hatch chicks and to diminish during post-hatch development.(ABSTRACT TRUNCATED AT 400 WORDS)

Absorption↗
PubMed1984

Sodium-ion dependence of glycine and lysine transport in chicken erythrocytes genetically selected for high and low leucine transport activity.

Amino acid transport was studied in two lines of chickens, one high and the other low uptake, selected for their ability to transport leucine into erythrocytes. On the basis of the number of mol of substrate transferred, medium Na+ was found to be more effective in stimulating glycine and lysine transport into high line cells than into low line cells. Glycine transport in both lines was stimulated by medium Na+ to a greater degree than was lysine transport. In the absence of medium Na+, glycine transport was not significantly different in the two lines. In the absence of medium Na+, lysine transport in the high line was about five-fold greater than in the low line. The transport differences between the lines are probably due to differences in several distinct genetic determinants.

Animals↗
PubMed1984

Development of nutrient transport systems in chick jejunum.

Glutamate, beta-alanine, choline, and myoinositol transport was characterized in jejunal slices and brush-border membrane vesicles from 2- and 21-day chicks. Carrier-mediated, i.e., competitor-inhibitable, transport in slices (wet weight basis) and vesicles (protein basis) declined with age for the two amino acids but increased with age for myo-inositol; transport of choline did not change. These findings, along with previous data for the hexose system, cannot be explained solely by nonspecific changes in brush-border membrane architecture or permeability or by changes in the electrochemical sodium gradient that drives cotransport. They indicate that each specific brush-border membrane transport mechanism follows separate developmental time tables.

Animals↗
PubMed1983

Developmental changes in amino acid transport in the chicken erythrocyte.

1. Influx of leucine, lysine and glycine was found to be highest in prehatch (day -1) chicken red blood cells and to diminish during posthatch development when tested at two and four weeks of age. 2. The greatest decline in transport rate during development was seen with leucine; lysine showed a substantial age-related decline only at substrate concentrations greater than Km, the apparent Michaelis constant of transport. 3. Vmax, the maximal transport influx, of each amino acid tested declined during development. 4. Km of glycine and leucine appeared to increase slightly over the test period. 5. In contrast, a 7-fold decrease in Km for lysine transport was seen over the same period. 6. These results are discussed in context of changes in kinetic parameters of amino acid transport during development reported for various animal organs or tissues.

Aging↗