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Biomedical subjects

W Morgan

Publications and source records attributed to W Morgan.

At least 37 records · Page 2Linked to original sources
PubMed1992

A scoring system for lung function tests in infants.

Measurements of thoracic gas volume (TGV), airway resistance (Raw), and airway conductance (Gaw) were calculated in a group of 42 normal infants using a whole-body plethysmograph. Maximum expiratory flow at functional residual capacity was measured in a separate group of 108 normal infants. Using data obtained from these infants the following regression equations were calculated: Gaw (L.s-1.cmH2O) = -0.0475 + 0.00164 x length (cm) square root of TGV (mL1/2) = -3.22 + 0.263 x length (cm) VmaxFRC (mL.s-1) = -173 + 5.2 x length (cm). The standard errors of prediction are a measure of the scatter of individual results from the normal population about the true regression line. They were used to define limits of the normal ranges for these tests of lung function, and to develop a scoring system. This approach is preferable to expressing results as percent predicted, which gives no indication of how likely a measurement is to be within normal limits.

Age Factors↗
PubMed1992

A biochemical and NMR spectroscopic study of hydrazine in the isolated rat hepatocyte.

Using isolated rat hepatocytes the biochemical effects of hydrazine have been investigated using both conventional assay techniques and high resolution proton NMR. High resolution proton NMR revealed that hydrazine caused a significant increase in alanine and lactate levels in the incubation buffer, whereas levels of beta-hydroxybutyrate were decreased. NMR also detected metabolites of hydrazine notably acetylhydrazine and a cyclised hydrazone formed with alpha-ketoglutarate. Changes were detected in NADH and NADPH, ATP, succinate dehydrogenase (SDH) and total non-protein sulphydryl groups (TNPSH). However, the changes in pyridine nucleotides occurred at higher concentrations than those affecting succinate dehydrogenase and ATP. Similarly, the depletion of TNPSH occurred at a higher concentration and with a different time course to that seen with ATP depletion and inhibition of succinate dehydrogenase.

Adenosine Triphosphate↗
PubMed1991

Hearing compensation evaluation.

Compensation claims for hearing loss are increasing. Physicians and audiologists supply necessary information regarding probable cause and amount of loss for evaluating these claims. Compensable hearing loss can arise from several sources. The principal activity has been claims based on industrial noise exposure. Compensation evaluation is considered as a consequence of noise-induced hearing loss, but the evaluation procedure is applicable regardless of the cause of hearing loss.

Audiometry↗
PubMed1989

Mechanisms of transformation by polyoma virus middle T antigen.

This review addresses a fundamental question of polyoma virus biology: What is the molecular mechanism by which the polyoma virus middle T antigen (MTAg) transforms cells in culture? Since MTAg has no known intrinsic biochemical activity, it is believed to act by modulating the properties of the host cell's proteins (see review by Courtneidge [26]). Experiments to date have largely focused on the interaction of MTAg with the cellular tyrosine kinase, pp60c-src. However, recent data from a number of laboratories have demonstrated the importance of other MTAg-associating cellular proteins in MTAg-mediated transformation, including pp62c-yes and a phosphatidylinositol kinase. In this review, we will summarize what is presently known about the proteins interacting with MTAg. The extent to which the currently known details of the biochemistry of MTAg and its associated proteins can explain the transforming properties of the various mutant alleles of MTAg will be assessed.

1-Phosphatidylinositol 4-Kinase↗
PubMed1989

The cellular proteins which can associate specifically with polyomavirus middle T antigen in human 293 cells include the major human 70-kilodalton heat shock proteins.

We compared the proteins which associate with middle T antigen (MT) of polyomavirus in human cells infected with Ad5(pymT), a recombinant adenovirus which directs the overexpression of MT, with the MT-associated proteins (MTAPs) previously identified in murine fibroblasts expressing MT. MTAPs of 27, 29, 36, and 63 kilodaltons (kDa) appeared to be fairly well conserved between the two species, as judged by comigration on two-dimensional gels. Several 61-kDa MTAP species detected in MT immunoprecipitates from both cell sources also comigrated on these gels. However, no protein comigrating precisely with the murine 85-kDa MTAP could be detected in the human cells. Furthermore, two proteins of 72 and 74 kDa associated with wild-type MT in the infected human cells but not in murine fibroblasts expressing MT. It had been previously reported for murine cells that the 70-kDa heat shock protein associates with a particular mutant MT but not with wild-type MT (G. Walter, A. Carbone, and W.J. Welch, J. Virol. 61:405-410, 1987). By the criteria of comigration on two-dimensional gels, tryptic peptide mapping, and immunoblotting, we showed that the 72- and 74-kDa proteins that associate with wild-type MT in human cells are the major human 70-kDa heat shock proteins.

Adenoviruses, Human↗
PubMed1989

Statistics and soap operas: population dynamics at Hopkins.

Since its inception in 1964, the Department of Population Dynamics has broken new ground in building interdisciplinary collaboration among the diverse fields of biological, social, and management sciences. The collaboration has produced uniquely well-prepared professionals, yielded some innovative research efforts, and advanced training and communication in the field of family planning. From Dr. Paul Harper's determination to build a center for sharing experiences in population planning, a world center for population dynamics has grown.

Baltimore↗
PubMed1989

Sleep apnea: morbidity and mortality of surgical treatment.

We have analyzed the complications in 132 patients who had surgical treatment of sleep apnea or excessive snoring. In this series there were 34 (26%) complications and two patients (1.5%) died. Complications related to uvulopalatopharyngoplasty in 126 patients included rhinolalia (2%) and oropharyngeal hemorrhage (6%). In the 41 patients who had tracheostomy, complications included hemorrhage from tracheostomy (5%), tracheomalacia (5%), peristomal infection (15%), tracheostomy tube intolerance (Montgomery tube 100%, Shiley tube 7%), pneumonia (2%), hypoxia necessitating emergency tracheotomy (2%), and other perioperative complications.

Adult↗
PubMed1988

Cellular proteins that associate with the middle and small T antigens of polyomavirus.

We have used two-dimensional gel electrophoresis to analyze in more detail the cellular proteins which associate with the middle and small tumor antigens (MT and ST, respectively) of polyomavirus. Proteins with molecular masses of 27, 29, 36, 51, 61, 63, and 85 kilodaltons (kDa) that specifically coimmunoprecipitated with MT were identified on these gels. The 36-, 51-, 61-, 63-, and 85-kDa proteins are probably the same as the proteins of similar sizes previously reported by a number of groups, whereas the 27- and 29-kDa proteins represent proteins that are heretofore undescribed. The 27- and 29-kDa proteins were abundant cellular proteins, whereas the others were minor cellular constituents. The association of each of these proteins with MT was sensitive to one or more mutations in MT that rendered it transformation defective. The association of the 85-kDa protein was the most sensitive indicator of the transformation competence of MT mutants. In addition, the 85-kDa protein was the only associated protein whose association with MT changed consistently in parallel with MT-associated phosphatidylinositol kinase activity. Furthermore, the fraction of the 85-kDa protein which was found associated with the MT complex contained 15 to 20% of its phosphate content on tyrosine. The 36- and 63-kDa proteins complexed with both polyomavirus MT and ST and comigrated on two-dimensional gels with two simian virus 40 ST-associated proteins originally described by Rundell and coworkers (K. Rundell, E. O. Major, and M. Lampert, J. Virol. 37:1090-1093, 1981). None of the other MT-associated proteins associated significantly with ST.

Antigens, Polyomavirus Transforming↗
PubMed1988

Obstetric ultrasound training for family physicians. Results from a multi-site study.

A practical program to train family physicians in obstetric ultrasound was tested with 13 family physicians. Each physician completed 6.5 days of course work and ultrasound laboratory apprenticeship prior to beginning a clinical preceptorship of approximately 14 months' duration. During the clinical preceptorship the physicians performed ultrasound studies in their own offices. All studies were reviewed by a local consultant radiologist utilizing examination data sheets and videotapes. At the conclusion of the training program, the physicians took a combined practical and written proficiency examination administered by an independent sonographer. Eight physicians completed the training, performing during the preceptorship an average of 78 examinations. The rated performance of the physicians improved markedly over the course of the preceptorship. During the last segment of the preceptorship the radiologist preceptors rated 94 percent of the ultrasound studies as acceptable, compared with 79 percent rated acceptable at the beginning of the preceptorship. Seven of the eight physicians completing the protocol took the proficiency examination: all passed. This study can provide a blueprint for an individual family physician to design his own training, or it can guide an academic department of family medicine in developing and evaluating ultrasound training programs for residents and practicing physicians.

Education, Medical, Continuing↗
PubMed1987

Total parenteral nutrition and intestinal development: a neonatal model.

Total parenteral nutrition (TPN) is widely used in premature and/or surgical neonates, but there is little information available about its effects on intestinal growth and development. Adult TPN models have demonstrated mucosal atrophy, and a young piglet model showed similar but increased intestinal hypotrophy. We have investigated these effects in the neonatal piglet model. Five three-day old piglets received a glucose (40 g/kg/d), amino acid (8 g/kg/d), and fat (4 g/kg/d) solution intravenously for 3 weeks. Matched littermates were fed an artificial sow-milk formula enterally at an equivalent caloric rate (215 kcal/kg/d). A third littermate was sow breast fed for the same study period. No differences were seen in the TPN or formula-fed piglets in weight gain (31 to 34 g/kg/d), hematocrit (25% to 27%), BUN (12 to 13 mg/dL), total serum protein (4.1 to 4.4 g/dL), or total bilirubin (0.4 to 0.6 mg/dL); however, the TPN animals were mildly hyperglycemic (167 mg/dL). The sow-fed control group had greater weight gain (51 g/kg/d) but were without caloric restriction. There were significant decreases in weight and length of the gastrointestinal tract, particularly in the proximal small bowel of the TPN piglets. Compared with formula piglets or sow-fed controls, the TPN proximal small bowel weight was reduced by 67% and 72%, respectively. Similar but less marked differences were seen in the TPN distal small bowel. There were no significant differences in the proximal or distal small bowel measurements between the formula and sow-fed piglets, despite their differences in overall weight gain.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Effects of psychoactive and non-psychoactive cannabinoids on neuroendocrine and testicular responsiveness in mice.

Repeated oral administration of the non-psychoactive cannabinol (CBN; 5 or 50 mg/kg) significantly reduced the concentration of norepinephrine (NE) in median eminence and greatly reduced NE levels 1 and 2 hrs after administration of alpha-methylparatyrosine (alpha-MPT). The levels of dopamine (DA) in median eminence were significantly different, as indicated by the differences in slopes obtained in CBN- treated and control mice before and after alpha-MPT. Plasma levels of luteinizing hormone (LH) were significantly reduced in CBN-exposed mice before alpha-MPT, elevated at 1 hr post-injection, but were also reduced 2 hrs post-injection at 50 mg/kg CBN. Follicle-stimulating hormone (FSH) levels were increased at 1 hr post-alpha-MPT in mice receiving 50 mg/kg CBN. Oral administration of CBN at 50 mg/kg for 4 days enhanced testicular testosterone (T) production in response to intratesticular in vivo injection of 2.5 or 25 mIU human chorionic gonadotropin (hCG). A single oral dose of the psychoactive delta 9-tetrahydrocannabinol (THC) enhanced the production of T 15 min after intratesticular LH (10 ng) injection. However, at 45 or 60 min post-THC treatment, the response to LH was significantly attenuated. These studies demonstrate that both psychoactive and non-psychoactive components of marihuana alter testicular responsiveness to gonadotropins in vivo. These effects may be biphasic, involving stimulation and inhibition of responsiveness, and appear to be correlated with alterations in plasma LH levels. Alterations in plasma gonadotropins may be mediated by cannabinoid effects on catecholamine concentrations in median eminence and THC-induced alterations in testicular responsiveness to gonadotropin probably also involve direct effects of THC at the gonadal level.

Animals↗
PubMed1984

Scapholunate dissociation from a fall on the elbow.

We report an undescribed mechanism of injury that caused scapholunate dissociation. Scapholunate dissociation has been previously described as resulting from a fall on the outstretched hand. In this case injury was caused by a fall on the elbow. The mechanism is compared to that of an axe head that is repositioned by butting the handle of the axe on the ground. Recognition of this mechanism may help in the diagnosis of this injury.

Carpal Bones↗
PubMed1984

Prescribing behaviors of primary care nurse practitioners.

The prescribing practices of 18 primary care nurse practitioners (NPs) with 1,683 patients over a six-month period were examined through a randomly selected audit of over 1,700 prescriptions. The results showed that NPs prescribed a very limited number of well known, relatively simple drugs to a young, female healthy population. The prescription/visit rate was 0.26. Most drugs were initiated for the first time rather than refilled. There was minimal physician consultation regarding drug use during the visit. The results provide evidence of the ability of nurse practitioners to prescribe drugs and should aid in the further legalization of this aspect of the primary care role.

Adolescent↗
PubMed1982

The measurement of total respiratory resistance in small children.

A new, simplified apparatus to determine total respiratory resistance (Rrs) was presented. This apparatus, which utilizes the principle of forced oscillation, is portable, relatively simple to operate and calibrate, and small children can be tested with no apparent difficulties. To investigate the usefulness of the apparatus, total respiratory resistance was measured in 101 healthy children, ages 3-5. Rrs was found to be the highest in the younger children and was decreased with increasing age. The greatest variability in Rrs was found among the youngest children. Linear regression equations for Rrs versus height, weight, and body surface area were established. The best correlation was found between Rrs and height (r = -.325; P less than 0.01) of the children. Utilizing the described apparatus, Rrs can be determined relatively easily without requiring special effort by the subject and is a useful tool to monitor the airways function of young patients.

Airway Resistance↗