Biomedical subjects

J M Kaplan

Publications and source records attributed to J M Kaplan.

At least 19 recordsLinked to original sources

PubMed1997

Safety of airway gene transfer with Ad2/CFTR2: aerosol administration in the nonhuman primate.

In this study, the safety and efficacy of aerosol delivery to non-human primates of an adenoviral vector encoding the cystic fibrosis transmembrane conductance regulator protein (CFTR) were evaluated. The technique of concurrent flow spirometry was used to determine the deposited dose of Ad2/CFTR-2, which ranged from 3 to 8 x 10(10) I.U. Transgene DNA was detected by the polymerase chain reaction (PCR) in lung tissue from all treated animals, and human CFTR mRNA was detected on days 3, 7, and 21 post-exposure. The treatment was well tolerated, with no evidence of respiratory distress. Histologic changes in the lungs from Ad2/CFTR-2-treated animals were mild and, overall, indistinguishable from animals exposed to aerosolized vehicle. One vector-treated animal demonstrated an increase in lavage lymphocyte numbers 3 days after treatment and another had an abnormal chest radiograph 14 days after treatment. A third vector-treated animal had histologic evidence of a bronchointerstitial pneumonia 7 days after aerosol treatment that resolved by day 21. This study demonstrated that Ad2/CFTR-2 can effectively be delivered to the lungs of nonhuman primates and result in minimal adverse effects.

Adenoviruses, Human↗

PubMed1997

Characterization of factors involved in modulating persistence of transgene expression from recombinant adenovirus in the mouse lung.

One potential limitation of adenovirus (Ad)-based vectors for the gene therapy of cystic fibrosis (CF) and other genetic diseases is the transience of expression observed in most in vivo systems. In this study, the influence of various factors on persistence of transgene expression in the lung was investigated. In the absence of immune pressure, such as in the nude mouse, the genomic structure of the vector was found to be predominant in determining the persistence of expression; Ad vector constructs with an E1-E3+E4ORF6+ backbone encoding beta-galactosidase (beta-Gal) or the cystic fibrosis transmembrane conductance regulator (CFTR) produced declining levels of expression while an Ad/CMV beta Gal vector with an E1-E3+E4+ backbone gave rise to sustained, long-term reporter gene expression. The ability of the latter vector to persist was in turn limited in part by the presence of cytotoxic T lymphocytes (CTLs). Adoptive transfer experiments indicated that CTLs directed against either viral proteins or the beta-Gal reporter gene product were able to reduce expression in nude C57BL/6 mice stably expressing beta-Gal from the E4+ vector. Finally, the specificity and strength of the CTL response elicited by Ad vector was found to vary considerably depending on mouse strain haplotype. These results indicate that persistence of transgene expression in a given system is determined by the interplay between several factors including genomic structure of the vector, host background, and immune response.

Adenoviridae↗

PubMed1997

Generation of cytotoxic T lymphocytes against immunorecessive epitopes after multiple immunizations with adenovirus vectors is dependent on haplotype.

Currently, adenovirus (Ad) is being considered as a vector for the treatment of cystic fibrosis as well as other diseases. However, the cytotoxic T lymphocyte (CTL) response to Ad could limit the effectiveness of such approaches. Since the CTL response to virus infection is often focused on one or a few immunodominant epitopes, one approach to circumvent this response is to create vectors that lack these immunodominant epitopes. The effectiveness of this approach was tested by immunizing mice with human group C adenoviruses. Three mouse strains (C57BL/10SnJ [H-2b], C3HeB/FeJ [H-2k], and BALB/cByJ [H-2d]) were immunized with wild-type Ad or Ad vectors lacking the immunodominant antigen(s), and the CTL responses were measured. In C57BL/10 (B10) mice, a single inoculation intraperitoneally (i.p.) led to the recognition of an immunodominant antigen in E1A. When B10 mice were inoculated multiple times either i.p. or intranasally with wild-type Ad or an Ad vector lacking most of the E1 region, subdominant epitopes outside this region were recognized. In contrast, C3H mice inoculated with wild-type Ad recognized an epitope mapping within E1B. When inoculated twice with Ad vectors lacking both E1A and E1B, no immunorecessive epitopes were recognized. The immune response to Ad in BALB/c mice was more complex. CTLs from BALB/c mice inoculated i.p. with wild-type Ad recognized E1B in the context of the major histocompatibility complex (MHC) class I Dd allele and a region outside E1 associated with the Kd allele. When BALB/c mice were inoculated with E1-deleted Ad vectors, only the immunodominant Kd-restricted epitope was recognized, and Dd-restricted CTLs did not develop. This report indicates that the emergence of CTLs against immunorecessive epitopes following multiple administrations of Ad vectors lacking immunodominant antigens is dependent on haplotype and could present an obstacle to gene therapy in an MHC-diverse human population.

Adenovirus E1A Proteins↗

PubMed1996

Relationships between antibodies against human soluble complement receptor 1 (hsCR1) from various species.

The relationships between antibodies against human soluble complement receptor 1 (hsCR1) were studied in rodents, dogs, nonhuman primates, and humans. An antibody response occurred in all species except humans. The anti-hsCR1 antibodies from the various species were characterized to determine if they recognize similar epitopes on the hsCR1 molecule. Dog and monkey sera, positve for hsCR1 binding, were used as blocking antibodies against mouse anti-hsCR1 monoclonal antibodies as well as mouse and rat anti-hsCR1-positive sera. Human sera (blood group antisera: anti-Knops, anti-McCoy, anti-Knops/McCoy, anti-Swain-Langley) and serum from one burn patient (who became seropositive despite ever receiving treatment with hsCR1) were also used to test blocking of mouse, rat, dog, and monkey anti-hsCR1. Characterization of anti-hsCR1 antibodies from different species demonstrated that hsCR1 causes divergent antibody responses among animals. While mouse, rat, and dog antibodies cross inhibit binding by approximately 50%, monkey antibodies recognize primarily different epitopes of the hsCR1 molecule. Moreover, human antibodies binding hsCR1 are completely different from the animal antibodies, including monkey. This study indicates that although hsCR1 is immunogenic in animals, there is a difference in response between species, particularly between nonprimates and primates, and finally, that this antibody response is not predictive for humans.

Animals↗

PubMed1996

Sensory signaling in Caenorhabditis elegans.

The simple anatomy, behavior, and genetics of the nematode Caenorhabditis elegans make it an attractive organism for studying sensory circuits and their functions in vivo. Recent advances in our understanding of C. elegans sensory signaling stem from work on topographic maps, chemosensory receptors, modality coding, and the integration of antagonistic sensory inputs.

Animals↗

PubMed1996

A new taste reactivity analysis of the integration of taste and physiological state information.

We used conjoint manipulation of taste and physiological state to address the theoretical issue of signal integration. The interaction between taste (glucose concentration) and state (food deprivation) was evaluated using the taste reactivity method in which oral motor responses elicited by direct intraoral infusion are measured. The time frame of the typical taste reactivity paradigm, where observation is limited to the infusion period, was expanded to include the postinfusion interval. In each test session, rats received a series of trials consisting of 15-s intraoral infusions and 45-s postinfusion observation intervals. Two experiments were run in which glucose concentration was varied and rats were run nondeprived and after 24 h food deprivation. In experiment 1, glucose concentrations (0, 3.2, 6.25, 12.5, and 25%) were randomly presented during each test session. In experiment 2, individual glucose concentrations (0, 6.25, or 25%) were presented during separate sessions. For both, a deprivation condition was flanked by nondeprived (baseline) sessions. Concentration-response functions were comparable in both experiments. In each experiment, the shape of the concentration-response function was dramatically different during and after infusions. During infusions, there were no increases in glucose-elicited rhythmic oral responses beyond a very dilute concentration. After infusions, the concentration-response functions appeared linear across the concentration range. In both experiments, deprivation elevated responding only in the after-infusion periods. In experiment 1, the concentration-response function was uniformly elevated (on average, 27%) by deprivation, which if taken at face value would suggest an additive combination of taste and state feedback signals. In experiment 2, however, deprivation increased responding (approximately 30%) for 6.25%, but not for 0 or 25%, suggesting a stimulus specificity of the taste-state integration. Clearly then, the taste-state profiles differed as a function of experimental design. In the GENERAL DISCUSSION, we suggest that the uniform elevation of responding to all glucose concentrations, and to water, seen in experiment 1, may be an artifact of the random presentation of all stimuli during individual sessions. Experiment 2, in which stimuli were presented in a between-sessions design, may provide a truer reflection of the underlying integrative process.

Animals↗

PubMed1996

Biological response of nonhuman primates to long-term repeated lung exposure to Ad2/CFTR-2.

We have assessed the safety and efficacy of repeated adenovirus vector administration by exposing the left caudal lung lobe of rhesus monkeys to as many as 17 exposures of Ad2/CFTR-2. After nine doses of either 3 x 10(9) or 3 x 10(10) infectious units, the monkeys were free of adverse effects as assessed by thoracic radiographs, CBCs, clinical chemistries, arterial blood gases, and physical and clinical signs. In some animals elevated protein levels and increased numbers of cells were recovered in bronchoalveolar lavage (BAL), and in all animals there were increased proportions of lymphocytes in the BAL. After 11 doses, two animals were killed. In the lower dose animal (3 x 10(9) IU), there was little histopathology evident. In the higher dose animal (3 x 10(10) IU), histopathology was largely confined to a focal fibrotic lesion that may have been associated with treatment. At the tenth exposure, the dose was increased to 6 x 10(10) or 3 x 10(11) IU. There was evidence of lung injury by thoracic radiographs after two additional exposures and an increase in protein and number of cells in the BAL. The animals were still free of evidence of adverse effects by other parameters, but histopathologic changes were noted upon death. After 15 or 17 doses, three animals were instilled with Ad2/beta gal-2 and killed 3 days later. These animals had greatly reduced levels of transgene expression when compared with controls.

Adenoviruses, Human↗

PubMed1996

Humoral and cellular immune responses of nonhuman primates to long-term repeated lung exposure to Ad2/CFTR-2.

To evaluate the host immune response to long-term repeat administration of adenovirus vector, rhesus monkeys were treated at intervals of approximately 3 weeks with up to 18 instillations of Ad2/CFTR-2, a second generation vector encoding the cystic fibrosis transmembrane conductance regulator (CFTR). All monkeys instilled with Ad2/CFTR-2 developed a significant humoral immune response against adenovirus but not CFTR. Antibodies with virus neutralizing activity were detected in the serum and bronchoalveolar lavage (BAL) of all vector-treated monkeys and included both IgG and secretory IgA. Virus-specific T cells capable of proliferating in response to stimulation with adenovirus antigen were detected in all vector-treated monkeys. No CFTR-specific proliferation of peripheral blood lymphocytes was detected. An increase in the proportion of CD8+ T cells was noted in the BAL of virus-treated monkeys but cells from the BAL displayed little or no cytolytic activity against infected autologous fibroblasts when tested under a variety of culture conditions. However, MHC-restricted cytolytic activity was detected in the tracheobronchial lymph nodes and spleen of one of three virus-treated monkeys tested. MHC-unrestricted killing of infected fibroblasts was also observed with spleen cells from all animals tested. From these results, it appears that both the humoral and cell-mediated arms of the immune response were stimulated by repeated administration of high doses of Ad2/CFTR-2 suggesting that effective, long-term adenovirus gene therapy may require modification of the vector or treatment of the host to allow the virus to evade host immune defenses.

Adenoviruses, Human↗

PubMed1995

Synaptic code for sensory modalities revealed by C. elegans GLR-1 glutamate receptor.

How does the nervous system encode environmental stimuli as sensory experiences? Both the type (visual, olfactory, gustatory, mechanical or auditory) and the quality of a stimulus (spatial position, intensity or frequency) are represented as a neural code. Here we undertake a genetic analysis of sensory modality coding in Caenorhabditis elegans. The ASH sensory neurons respond to two distinct sensory stimuli (nose touch and osmotic stimuli). A mutation in the glr-1 (glutamate receptor) gene eliminates the response to nose touch but not to osmotic repellents. The predicted GLR-1 protein is roughly 40% identical to mammalian AMPA-class glutamate receptor (GluR) subunits. Analysis of glr-1 expression and genetic mosaics indicates that GLR-1 receptors act in synaptic targets of the ASH neurons. We propose that discrimination between the ASH sensory modalities arises from differential release of ASH neurotransmitters in response to different stimuli.

Animals↗

PubMed1995

Modulation of serotonin-controlled behaviors by Go in Caenorhabditis elegans.

Seven transmembrane receptors and their associated heterotrimeric guanine nucleotide-binding proteins (G proteins) have been proposed to play a key role in modulating the activities of neurons and muscles. The physiological function of the Caenorhabditis elegans G protein Go has been genetically characterized. Mutations in the goa-1 gene, which encodes an alpha subunit of Go (G alpha o), cause behavioral defects similar to those observed in mutants that lack the neurotransmitter serotonin (5-HT), and goa-1 mutants are partially resistant to exogenous 5-HT. Mutant animals that lack G alpha o and transgenic animals that overexpress G alpha o [goa-1(xs) animals] have reciprocal defects in locomotion, feeding, and egg laying behaviors. In normal animals, all of these behaviors are regulated by 5-HT. These results demonstrate that the level of Go activity is a critical determinant of several C. elegans behaviors and suggest that Go mediates many of the behavioral effects of 5-HT.

Animals↗

PubMed1995

Effect of TNF alpha production inhibitors BRL 61063 and pentoxifylline on the response of rats to poly I:C.

BRL 61063 is a novel xanthine phosphodiesterase (PDE) type IV inhibitor with selective inhibitory activity for tumor necrosis factor (TNF) alpha production. This compound inhibits TNF alpha production by activated human blood monocytes in vitro and in animal models of endotoxemia and influenza infection. Inhibition of TNF alpha may be beneficial in many diseases; however, little is known about potential adverse effects of such inhibition on host defense. In an ex vivo study, we examined the effect of BRL 61,063 on the microbicidal and tumoricidal activity of pulmonary lavage cells during a local inflammatory response in rats challenged with Poly I:C. Pentoxifylline, a PDE inhibitor which also blocks TNF alpha production, was used for comparison. Treatment with BRL 61063 or pentoxifylline did not block the inflammatory response to Poly I:C or the activation of bronchoalveolar lavage (BAL) cells but reduced the level of tumoricidal activity attained. At the dosages used, pentoxifylline was more inhibitory than BRL 61063. Drug treatment did not prevent further stimulation of tumoricidal activity by LPS in vitro. LPS-stimulated cells from BRL 61063-treated rats reached a level of activation similar to the control group while the LPS-stimulated activity of BAL cells from pentoxifylline treated rats remained lower than control. Although pentoxifylline was more inhibitory for tumoricidal activity than BRL 61063, the latter was a more potent inhibitor of TNF alpha release as measured in vivo in LPS-challenged rats. This finding indicates that TNF alpha is not the main mediator involved in the activation of pulmonary macrophage tumoricidal function. Treatment with either BRL 61063 or pentoxifylline had little or no effect on the Poly I:C-induced candidacidal activity of BAL cells indicating that these compounds are unlikely to compromise non-specific host defense against infection.

Animals↗

PubMed1995

Effect of occluding the pylorus on intraoral intake: a test of the gastric hypothesis of meal termination.

Meal size does not change in response to food being restricted to the stomach by occlusion of the pylorus. This result has been used as evidence for a gastric model of meal termination where feedback arising solely from the stomach is taken to underlie satiation. Such data provide support for the gastric model, however, only if the rate of gastric emptying during ingestion in the unoccluded condition is slow, such that comparable amounts of food would be found in the stomach at the end of the meal in both the pylorus-occluded and unoccluded conditions. To evaluate this tissue directly, rats were implanted with pyloric cuffs and gastric cannulas and given an intraoral intake test of a 10.5% glucose solution with either the pylorus occluded or unoccluded. At the end of each intraoral intake test, the content of the stomach was removed via the gastric cannula and it's volume and concentration measured. Occlusion of the pylorus did not change meal size, but both the volume and grams of glucose solute found in the stomach were substantially greater in the pylorus-occluded condition. These results are not consistent with the hypothesis that the stomach is the sole source of inhibitory signals that terminate a meal. Cumulative intake would appear to be accurately tracked regardless of its distribution within the digestive tract.

Animals↗

PubMed1995

Ingestive taste reactivity as licking behavior.

In ingestive taste reactivity analysis, the rhythmic oral motor responses observed during intraoral infusion of fluids normally ingested by rats are categorized and counted. These rhythmic movements can be likened to spout-licking in several respects. Both are emitted in the same frequency range (5-8 Hz), organized in a burst/pause pattern, and serve the function of intraoral transport of fluid into position for swallowing. The parallel suggests that a temporal pattern analysis, based on the spout-licking literature, can be fruitfully applied to the rhythmic movements that attend intraoral infusion. We provide a demonstration of such an analysis using an electromyographic (EMG) recording-based method for automated event detection. Eight rats received a 37.5% glucose solution (1.0 ml/min) in a series of 120 s infusion trials (45 s intertrial intervals) that was extended until the fluid was rejected. Movement counts declined 19.1% from the first to the last complete trial. Parameters derived from the pattern analysis (number of bursts, mean burst duration, pause durations, coefficient of variation for the distribution of within-burst intermovement intervals) were affected to a greater extent. The results indicate the potential value of temporal pattern analysis for various applications of the taste reactivity paradigm.

Animals↗

PubMed1995

Fourth ventricle injection of corticotropin-releasing factor and gastric emptying of glucose during gastric fill.

The effect of corticotropin-releasing factor (CRF) administered into the fourth ventricle on the gastric emptying of a 12-ml intragastric infusion of 12.5% D-glucose was examined in nondeprived male rats. All three CRF doses tested (10, 100, and 1,000 pmol) significantly reduced (by 28, 29, and 44%, respectively) the amount of glucose emptied from the stomach at the end of the 12-min (1.0 ml/min) gastric infusion interval. The 10 pmol effective dose is the lowest yet reported to influence gastric emptying. The receptor specificity of the exogenous CRF (1,000 pmol) effect was demonstrated by its complete blockade by preinjection of alpha-helical CRF-9-41 (10 nmol) into the fourth ventricle. Injection of the antagonist alone, however, did not affect glucose emptying, indicating little activation of the targeted receptors under the present nonstressful, baseline conditions. Our results suggest that of the central CRF receptor systems that influence gastric emptying, those in the caudal brain stem, targeted by fourth ventricular injection, may be of particular importance.

Anastomosis, Surgical↗

PubMed1994

Apomorphine suppresses ingestive behaviour in chronic decerebrate rats.

To determine whether dopamine receptors in the brain stem can mediate inhibition of feeding behaviour male rats in which the forebrain was disconnected from the brain stem were studied. Such decerebrate rats do not approach food but display ingestive responses if infused intraorally with a 1 M solution of sucrose at 0.6 ml min-1. Intraperitoneal injection of 5 micrograms cholecystokinin octapeptide, a physiological satiety peptide, or 400 micrograms apomorphine, a dopamine D1-D2 receptor agonist, suppressed intake of the sucrose solution. The results support a role of brain stem dopamine receptors in the control of ingestive behaviour.

Animals↗

PubMed1994

Multiple immunizations. Ouch!

The purpose of this study was to determine the stated willingness of parents/caretakers to allow the administration of multiple, injected immunizations to their children at a single visit. Two hundred eighty-one parents/caretakers accompanying their children to an inner-city pediatric clinic were presented with hypothetical situations in which their children would be due for two, three, or four injections to complete their series of age-appropriate immunizations. Given a scenario of two needed injections, 24 (8.5%) of the 281 parents/caretakers preferred to divide the injections between two visits; for three injections, 119 (42.3%) preferred two visits; and for four injections, 164 (58.4%) preferred two visits. The commonly stated preference of our predominantly minority parent/caretaker population to divide more than two injections between two visits seriously conflicts with the US Public Health Service's National Vaccine Advisory Committee's recommendations and potentially exacerbates immunization delays. Therefore, physicians must be prepared to strongly urge simultaneous administration of all needed vaccine doses at any opportunity.

Adult↗

PubMed1994

Readability of the childhood immunization information forms.

OBJECTIVE: To compare the reading level required to understand childhood immunization information forms with the reading grade level of an inner-city parent/caretaker population. DESIGN: Descriptive study (parents/caretakers). SETTING: Inner-city pediatric clinic. PARTICIPANTS: One hundred fifty English-speaking, low-income parent/caretakers. INTERVENTIONS: None. MEASUREMENTS/MAIN RESULTS: The reading level of our parent population ranged from grades 2.9 to 13.3, with a median grade level of 6.90. The reading levels required for the three vaccine information pamphlets issued in 1992 by the Centers for Disease Control and Prevention (Atlanta, Ga) averaged 11.1 (approximately at the level of a high school junior). Eighty-six percent of our parents/caretakers did not have a reading level sufficient to cope with the easiest of the forms. CONCLUSIONS: The vaccine information pamphlets require a reading level beyond the capability of the vast majority of our parent population. Therefore, the goal of informed consent clearly is not being met.

Adolescent↗

PubMed1994

Effects of soup preloads on gastric emptying and fullness ratings following an egg sandwich meal.

To identify the source of inhibitory signals from the stomach or intestine that lead to satiation, the effects of 300-g tomato soup preloads on the gastric emptying of a solid meal and on hunger and fullness ratings were examined. Subjects were nine healthy women who each ingested an egg sandwich: 1) with no soup, 2) immediately after the soup, and 3) 20 min after the soup. Emptying of the sandwich was measured using radionuclide scintigraphy. Soup significantly prolonged the lag phase (period before significant emptying occurred, p < 0.05), and the half-emptying time (p < 0.01) of the sandwich, but only when ingested immediately before the sandwich. Thus, soup affected the emptying of the sandwich when the volume of soup in the stomach was at a maximum. Passage of soup into the duodenum over a 20-min period had no effect on emptying of the sandwich. Despite the different gastric/postgastric distributions of the soup and the sandwich in the two preload conditions, fullness ratings were not different.

Adult↗