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Biomedical subjects

M Webber

Publications and source records attributed to M Webber.

At least 19 recordsLinked to original sources
PubMed2003

LTP but not seizure is associated with up-regulation of AKAP-150.

We have used differential display to profile and compare the mRNAs expressed in the hippocampus of freely moving animals after the induction of long-term potentiation (LTP) at the perforant path-dentate gyrus synapse with control rats receiving low-frequency stimulation. We have combined this with in situ hybridization and have identified A-kinase anchoring protein of 150 kDa (AKAP-150) as a gene selectively up-regulated during the maintenance phase of LTP. AKAP-150 mRNA has a biphasic modulation in the dentate gyrus following the induction of LTP. The expression of AKAP-150 was 29% lower than stimulated controls 1 h after the induction of LTP. Its expression was enhanced 3 (50%), 6 (239%) and 12 h (210%) after induction, returning to control levels by 24 h postinduction. The NMDA receptor antagonist CPP blocked the tetanus-induced modulation of AKAP-150 expression. Interestingly, strong generalized stimulation produced by electroconvulsive shock did not increase the expression of AKAP-150. This implies that the AKAP-150 harbours a novel property of selective responsiveness to the stimulation patterns that trigger NMDA-dependent LTP in vivo. Its selective up-regulation during LTP and its identified functions as a scaffold for protein kinase A, protein kinase C, calmodulin, calcineurin and ionotropic glutamate receptors suggest that AKAP-150 encodes is an important effector protein in the expression of late LTP.

A Kinase Anchor Proteins↗
PubMed2001

An evaluation of Open Airways for Schools: using college students as instructors.

Fifteen years ago, Open Airways for Schools (OAS) was found to be an effective asthma education program for elementary school children when taught by professionals. To determine whether OAS is effective when taught by college students and whether it could withstand potential cohort effects, 54 inner-city fourth and fifth graders were taught OAS. Paired t-tests revealed that OAS improved asthma knowledge, self-efficacy, self-management skills, social support, and perception of well-being (p < 0.05). Fifteen years later OAS continues to improve children's self-management skills. Facilitators with little prior experience who received brief training in asthma knowledge and group leadership skills can effectively teach OAS.

Asthma↗
PubMed1999

Osteonectin promotes prostate cancer cell migration and invasion: a possible mechanism for metastasis to bone.

The mechanism underlying the "organ-specific" metastasis of prostate cancer cells to the bone is still poorly understood. It is not clear whether the cells only invade the bone and proliferate there or whether they invade many tissues but survive mainly in the bone ("seed and soil"). Extracts from various organs were used as chemoattractants in the in vitro chemotaxis and invasion assays. Results show that, in comparison with extracts of other tissues, bone extracts promote a 2- to 4-fold increase in chemotaxis by human prostate epithelial cells and a 4-fold increase in the invasive ability of human prostate carcinoma cells. The purified active factor from bone and from marrow stromal-cell-conditioned medium is a low glycosylated osteonectin that specifically promotes the invasive ability of bone-metastasizing prostate (and breast) cancer cells but not that of non-bone-metastasizing tumor cells. It does not stimulate the growth of prostate cancer cells in vitro or in vivo. Because osteonectin specifically enhances matrix metalloprotease activity in prostate and breast cancer cells (and not in other tumor cell types), we conclude that prostate cancer cell metastasis to the bone is, in part, mediated by the ability of osteonectin to promote migration, protease activity, and invasion.

Bone Neoplasms↗
PubMed1995

Acute and chronic effects of marijuana smoking on pulmonary alveolar permeability.

Pulmonary clearance of technetium (99mTc)-labeled diethylene triamine pentaacetate (DTPA), a sensitive test of alveolar epithelial permeability, was measured twice in 34 healthy subjects, including 10 control nonsmokers (NS), 10 habitual smokers of marijuana alone (MS) (> or = 10 joints/wk), 9 regular smokers of tobacco alone (TS) (> or = 15 cigarettes/day) and 4 habitual smokers of both marijuana and tobacco (MTS). In smokers, the first study was performed after > or = 12 hrs of abstinence from smoking to assess chronic effects of marijuana and/or tobacco smoking on alveolar permeability; the second study was performed within 15 min of smoking to assess possible acute effects. TS exhibited abnormally rapid 99mTc-DTPA clearance after > or = 12 hours of abstinence, indicating an increase in pulmonary epithelial permeability, consistent with chronic tobacco-induced lung injury. MS showed a more modest and less consistent chronic effect than TS on 99mTc-DTPA clearance, suggesting a more variable and smaller degree of marijuana-induced lung injury. No acute effect of tobacco or marijuana smoking on 99mTc-DTPA clearance was apparent. Concomitant habitual smoking of marijuana and tobacco had no additive effect on alveolar permeability.

Adult↗
PubMed1994

Clinical signs and symptoms in pulmonary embolism. A reassessment.

The clinical diagnosis of pulmonary embolism (PE) remains difficult despite years of investigation. The clinical signs and symptoms of pulmonary embolism are numerous, but they are not diagnostically accurate. Radionuclide ventilation perfusion imaging (VQ) has become an important adjunct in screening patients for suspected PE. This study re-evaluates the predictive capabilities of various clinical signs and symptoms in a population of patients in whom angiography was thought to be necessary because of clinical concern for PE. One hundred one patients with suspected PE were retrospectively identified. Clinical information on them was complete, and laboratory studies, VQ imaging, and pulmonary angiography were performed. Thirty-seven clinical signs, symptoms, and other characteristics were individually compared for patients whose angiographic results were positive or negative for PE. Modifying or interactive effects on PE were then examined with logistic regression analysis. Several clinical conditions, including immobilization and recent surgery, were significantly associated with PE. Shortness of breath and history of smoking were significantly associated with negative results on pulmonary angiography. A "high probability" VQ scan was highly predictive (P < .0001) of positive results on angiography. When interactive factors for PE were examined, lack of shortness of breath and arterial pH < or = 7.45, lack of shortness of breath and respiratory rate > 23, diaphoresis in a nonsmoker and immobilized female, were significantly associated with PE. This study again documents the difficulty in using clinical criteria--including signs, symptoms, and laboratory determinations--to predict PE accurately, even in a population in which PE was of clinical concern irrespective of the VQ scan results.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1990

Posterior midbrain-induced locomotion.

The purpose of this study was to determine the nature of the neurochemical signals which impinge on the mesencephalic locomotor region (MLR) to produce locomotion in the rat. Injections of GABA antagonists into NADPH diaphorase-positive regions (PPN) were found to induce locomotion for short episodes (5-30 sec) which were repeated for several minutes (1-40 min). Such activity was blocked by injections of GABA and the GABA agonist, muscimol. Locomotion was induced by injection of substance P (SP), which also produced short, repeated episodes of locomotion. The more potent excitatory amino acid agonist, n-methyl-d-aspartic acid (NMDA), however, did produce dose-dependent, long-lasting (20 sec-5 min) locomotor episodes which were repeated over prolonged periods at the higher concentrations used (2-24 min). Additional injections of NMDA could drive stepping from a walk to a trot to a gallop. The effects of NMDA were blocked by injections of the excitatory amino acid antagonist, aminophosphonovalerionic acid (APV) (1-10 mM). Preliminary evidence suggests that carbachol (10-50 mM), a cholinergic agonist, inhibits NMDA-induced increases in muscle tone and episodes of stepping. The effect of carbachol was blocked by the cholinergic antagonist, atropine.

Animals↗
PubMed1990

Medioventral medulla-induced locomotion.

Previous anatomical studies demonstrated the presence of descending projections from the physiologically identified mesencephalic locomotor region (MLR) to the medioventral medulla (MED) in the cat. The present experiments were designed to determine if a similar low threshold locomotion-inducing area is present in the rat medulla. In addition, the nature of the neurochemical control of this area of the brain was explored using localized injections of neurochemical agents in the decerebrate rat during locomotion on a treadmill. A region virtually identical to that reported in the cat was found to lead to controlled locomotion on a treadmill following stimulation at low amplitude currents (less than or equal to 60 microA). Injections of cholinergic agonists into the MED of the rat induced locomotion which could be blocked by injections of cholinergic antagonists. In addition, injections of GABA antagonists were found to induce stepping which could be blocked by injections of GABA or GABA agonists. Substance P (SP) also was found to induce walking following injection into the MED of the rat. Injections of an excitatory amino acid agonist (NMDA) also were found to induce locomotion in the rat. These effects were blocked by injections of an excitatory amino acid antagonist (APV). Since these results had not been reported for the cat MED, a short series of experiments revealed that the MED in the cat also responded to NMDA.

Animals↗
PubMed1990

A seroprevalence survey for human immunodeficiency virus antibody in mentally retarded adults.

The prevalence of human immunodeficiency virus (HIV) infection among adults who are mentally retarded is not known. Policies for those in residential settings are being established despite incomplete information. Knowledge regarding HIV seroprevalence would enable administrators to make more effective policy decisions concerning testing and HIV prevention. Discarded sera from mentally retarded adults were anonymously tested for HIV antibody. Sera were collected from a health facility in Westchester County, NY, that provides care to developmentally disabled adults. After identifications were removed, sera were coded and linked to demographic and clinical variables from hospital and laboratory records. Sera came from individuals living in both institutional and less restrictive community settings in metropolitan New York City and more distant locations in New York State, all of whom were seen by the above facility. No HIV antibody was detected in sera from 241 mentally retarded adults. This study suggests that the prevalence of HIV antibody in mentally retarded adults is not high. Mandatory screening programs may not be appropriate for these individuals. Monies might be better spent on educational programs directed at AIDS prevention, and further development of ethical and safe policies for those who are mentally retarded.

Adolescent↗
PubMed1981

The Luftsichel: an old sign in upper lobe collapse.

The Luftsichel is a paramediastinal translucency due to interposition of the apex of the lower lobe between the mediastinum and the shrunken upper lobe. It occurs more commonly on the left than the right. It is so common on the left that it should be regarded as the typical appearance. It is to be distinguished from mediastinal hernia.

Bronchial Neoplasms↗
PubMed1978

Identification of cultured, human, malignant, prostatic epithelial cells.

Identification of cloned cells is necessary for experimentation with them. This paper details a method for the identification of cultured human malignant prostatic epithelial cells derived from metastatic deposits of prostate cancer by localization of a specific rabbit antiserum to human prostatic acid phosphatase in the cells.

Acid Phosphatase↗
PubMed1975

Isolation and identification of the human malignant prostatic epithelial cell in pure monolayer culture.

Isolation of the human malignant prostatic epithelial cell in pure monolayer culture was accomplished by clonal growth of single cells derived from metastatic deposits of prostatic carcinoma. Identification of these cells was established by the fact that the acid phosphatase of the prostatic epithelial cell is not inhibited by immersion in 10 per cent neutral formalin up to 24 hours, whereas all other acid phosphatases are destroyed by the formalin.

Acid Phosphatase↗