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Biomedical subjects

J Carlson

Publications and source records attributed to J Carlson.

At least 145 records · Page 8Linked to original sources
PubMed1995

Therapeutic regimens in acute experimental pancreatitis in rats: effects of a protease inhibitor, a beta-agonist, and antibiotics.

The osmolality of contrast injected retrograde into the rat pancreatic duct did not affect the severity of the pancreatitis (Urografin, 1,300 mOsm/kg, and Hexabrix, 580 mOsm/kg). The severity of the pancreatitis induced in rats was assessed by survival rate, histologic grading, wet lung ratio, and serum levels of amylase, lipase, and trypsin-like activity. Rats with pancreatitis induced by retrograde injected Urografin, lipopolysaccharide, taurocholic acid plus enterokinase were treated with either intravenous (i.v.) FUT-175 (Nafamstat Mesilate), FUT-175 administered by retrograde pancreatic injection, i.v. terbutaline, i.v. piperacillin sodium, piperacillin sodium by retrograde pancreatic duct injection, or a combination of FUT-175 plus terbutaline and piperacillin. Survival among the rats was increased and the incidence of pancreatic infection reduced in rats treated with i.v. piperacillin or with a combination of FUT-175 plus i.v. terbutaline, plus i.v. piperacillin compared to controls.

Acute Disease↗
PubMed1995

Factors associated with the stages of alcohol use among inner city school youth.

This study explored stages of alcohol acquisition and risk-factors associated with stages based on the Multi-Component Motivational Stages model. Two hundred fifty-four sixth-eighth grade students from an urban school completed a confidential questionnaire. Most students were in a precontemplation stage (86%), preparation stage (6%), or action stage (5%) for alcohol use. Significant differences were found across stage status on 11 of 22 risk factors. Discriminant analysis results indicated alcohol use, perceived prevalence of alcohol consumption, and intentions to drink in the future successfully discriminated youth in action and preparation from those in precontemplation and contemplation stages. Meanwhile, tobacco use discriminated students in preparation and action stages. Multiple regression analysis showed alcohol use was the most powerful predictor of acquisition stage status, followed by intentions, influenceability, and perceived severity of alcohol use. Implications for school-aged youth alcohol use prevention are discussed.

Adolescent↗
PubMed1995

Molecular genetic manipulation of mosquito vectors.

Despite their central role in disease transmission, relatively little is known of the molecular biology of arthropod vectors. Modern molecular approaches will undoubtedly provide considerable information about gene regulation and expression in vectors and consequently a much better understanding of the biology and molecular biology of vectors. Such knowledge is essential for developing effective control strategies for vector-borne diseases. In this review, we focus upon techniques and approaches used at the Arthropod-Borne and Infectious Diseases Laboratory (AIDL) at Colorado State University to bioengineer mosquitoes with reduced vector competence. We have developed technologies and procedures that allow genetic manipulation of mosquitoes, including RNA and DNA virus gene-delivery vehicles and efficacious antiviral constructs, which will facilitate the development of pathogen-resistant, transformed mosquitoes. Many of the approaches, constructs, and technologies developed at AIDL will be applicable to molecular manipulation of other arthropod genomes.

Animals↗
PubMed1995

Reduction in sympathetic activity after long-term CPAP treatment in sleep apnoea: cardiovascular implications.

Twelve patients with severe obstructive sleep apnoea were included in an open, long-term, prospective, follow-up study addressing the effects of nasal continuous positive airway pressure (CPAP) on sympathetic activity, cardiac structure and blood pressure. Plasma norepinephrine (P-NE) (daytime at rest), daytime and night-time urinary excretion of NE (U-NE), vanylmandelic acid and metanephrines, together with 24 h noninvasive blood pressure (BP) recording and Doppler-echocardiography, were assessed before and after a mean of 20.5 (range 14-26) months of CPAP. Average self-reported use of CPAP was 89% (range 65-100%) of time spent in bed. Resting daytime P-NE ranged 0.35-0.83 ng.ml-1, which is elevated compared to healthy controls. Only night-time U-NE, mean daytime BP and average 24 h BP were related to severity of OSA. Night-time metanephrine was related to daytime and night-time diastolic, as well as night-time systolic, BP. Left ventricular mass index (LVMI) at baseline was correlated to daytime systolic BP and P-NE. Long-term CPAP treatment reduced biochemical markers of sympathetic activity. P-NE decreased by approximately 50%, and daytime and night-time vanylmandelic acid and metanephrine by 32-54%. In contrast, there were no overall reductions in BP or LVMI. It is concluded that obstructive sleep apnoea is associated with high sympathetic activity both during sleep and waking periods. Urinary metanephrine excretion seemed to reflect blood pressure, but neither daytime nor night-time catecholamine excretion was directly related to disease severity in patients with severe obstructive sleep apnoea.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1994

Natural protection against severe Plasmodium falciparum malaria due to impaired rosette formation.

Genes for two lethal diseases, thalassemia and sickle cell anemia, are favored by evolution because, in their heterozygous form, they protect against cerebral malaria. Rosette formation, the binding of uninfected red cells (RBCs) to Plasmodium falciparum-infected RBCs (PRBCs), has previously been found to be associated with cerebral malaria, the most important severe manifestation of P falciparum malaria. We show here that thalassemic RBCs and, under certain conditions, even hemoglobin S (HbS)-containing RBCs possess an impaired ability to bind to PRBCs, forming small and weak erythrocyte rosettes compared with rosettes formed by normal RBCs. This decreased rosetting ability is associated with the small size of the thalassemic RBCs and with distortion of the mechanical properties of HbS-containing RBCs. The impairment of rosette formation may hinder the development of cerebral malaria by abatement of sequestration.

Anemia, Sickle Cell↗
PubMed1994

OS9: a novel olfactory gene of Drosophila expressed in two olfactory organs.

A novel olfactory gene, OS9, has been identified in Drosophila by subtractive hybridization. OS9 transcripts have been detected in the third antennal segment, the primary olfactory organ in Drosophila, and in the maxillary palp, which has recently been shown to have olfactory function. The OS9 gene thus represents a molecular link between two distinct olfactory tissues in Drosophila. Little if any OS9 expression has been detected in other segments of the antenna or in other tissues examined. The gene is located in region 38AB on the cytogenetic map. OS9 encodes a protein of 159 amino acids, which contains a putative leucine zipper. Polyclonal antibodies raised against the C-terminal half of the encoded protein react with a 24 kD antennal protein. Antisera raised against both C-terminal and N-terminal halves of the OS9 protein appear to react with cell nuclei in both the third antennal segment and the maxillary palp; interestingly, both antisera also stain cells in the head, including photoreceptor nuclei, as if OS9 were an olfactory-specific member of a family of nuclear proteins, possibly transcription factors.

Amino Acid Sequence↗
PubMed1994

Developmental analysis of the smellblind mutants: evidence for the role of sodium channels in Drosophila development.

We have recently found evidence that two smellblind mutants, originally identified as olfactory mutants, define a new class of mutation in the para (paralytic) sodium channel gene (Lilly et al., in press). These two mutants have previously been shown to be heat-sensitive developmental lethals: animals raised at elevated temperatures die as embryos or as young larvae (Lilly and Carlson, 1990, Genetics 124, 293-302). This article shows, surprisingly, that both mutants are not only heat-sensitive lethals, but also cold-sensitive lethals: when raised at reduced temperatures, the mutants develop to the adult stage, but then die prematurely. Moreover, this effect is sexually dimorphic, in that lethality is substantially greater for females than males. The association of cold-sensitivity with mutations of a sodium channel gene has recently been found in the case of a cold-sensitive human muscle disease, paramyotonia congenita, in which sodium channel function is defective (Ptacek et al., 1992, Neuron 8, 891-897). The heat-sensitive and cold-sensitive periods for the two smellblind mutants are determined through a series of reciprocal temperature shift experiments and are found to be different. Most, if not all, of the contribution to the heat-sensitive lethality occurs before metamorphosis, whereas the cold-sensitivity is particularly pronounced after the onset of metamorphosis. These results are discussed in terms of the developmental role of the para sodium channel and the role of electrical activity in Drosophila development.

Animals↗
PubMed1994

Rosetting.

Why do some individuals get severe falciparum malaria while others don't? Rosetting (the binding of uninfected erythrocytes to Plasmodium falciparum-infected erythrocytes), together with endothelial cytoadherence, has been shown to play a crucial role in the obstruction of the microvosculoture in P. falciparum malaria. Here, Mats Wahlgren, Victor Fernandez, Carin Scholonder and Johan Carlson review the literature surrounding rosetting.

Journal Article↗
PubMed1994

Characteristics of magnetic resonance sequences used for imaging silicone gel, saline, and gel-saline implants at low field strengths.

RATIONALE AND OBJECTIVES: Low-field magnetic resonance imaging (MRI) evaluation of breast implants is described, with emphasis on the capabilities provided by different imaging sequences. METHODS: Open architecture MR images using a .064-T permanent magnet and three-dimensional Fourier transform and inversion recovery sequences were obtained. A breast coil was designed and built for this project. Symptomatic and asymptomatic patients with silicone, saline-silicone and saline implants, and phantoms were part of this study. Phase images were used to differentiate protons in silicone, water, and fat. RESULTS AND CONCLUSIONS: Low-field MRI permitted differentiation of silicone, water, and fat. Implant anatomy and surrounding pathology could be imaged and identified.

Adult↗
PubMed1994

IgE elevation and IgE anti-malarial antibodies in Plasmodium falciparum malaria: association of high IgE levels with cerebral malaria.

In the course of studying immunoregulation in human Plasmodium falciparum malaria we have investigated IgE levels and IgE anti-plasmodial antibodies in children and adults from areas of high malaria endemicity in both Africa and Asia. On average, 85% of all donors had significantly elevated levels of total IgE. A fraction of the IgE had anti-plasmodial activity as revealed by ELISA with lysates of infected erythrocytes as antigen. Using synthetic peptides representing antigenic regions of two major plasmodial blood stage antigens, IgE antibody concentrations ranged from 5 to 15 ng/ml serum for each of the peptides. On average, the concentrations of the corresponding IgG antibodies were x 500-1000 higher. Immunoblotting of parasite lysates showed that most donors had IgE antibodies against one or several of a restricted number of plasmodial polypeptides, with antibodies against an antigen of mol.wt 45 kD already being present in all donors at an early age. Donors having IgE antibodies to particular antigens also frequently had corresponding IgG4 antibodies, reflecting underlying IL-4-dependent cellular mechanisms controlling formation of these isotypes. As infection with other parasites such as helminths is known to induce IgE elevation, the results do not prove that plasmodial infections were the primary cause of IgE induction. However, the importance of plasmodial infection for IgE elevation was supported by the finding of significantly higher levels of IgE, but not of IgG, in children with cerebral malaria compared with patients with uncomplicated disease.

Adolescent↗
PubMed1994

Munchausen syndrome by proxy: an unexpected cause of severe chronic diarrhoea in a child.

A six-year-old boy with severe intermittent diarrhoea was subjected to extensive diagnostic investigation and treatment before the administration of a laxative (sodium sulphate) by his mother was discovered. Early suspicion and analysis of faecal fluid for electrolytes and known laxative substances would have prevented the hazardous clinical course of this case.

Cathartics↗