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Biomedical subjects

M Green

Publications and source records attributed to M Green.

At least 613 records · Page 34Linked to original sources
PubMed1985

The maximal sniff in the assessment of diaphragm function in man.

We studied diaphragm function in a total of 64 normal subjects, who had no past or present respiratory or neuromuscular impairment. We measured transdiaphragmatic pressure (Pdi) during maximal sniffs and compared these values with Pdi during maximal static inspiratory efforts (PImax.). The range of Pdi during maximal sniffs (82-204 cm H2O) had better defined lower limits than Pdi during PImax. (16-164 cm H2O) and a higher mean value: mean +/- SD for maximal sniffs was 137 +/- 28 cm H2O and for PImax. was 90 +/- 37 cm H2O. The reproducibility of sniff Pdi was assessed in eight randomly chosen subjects over 3 days: the mean coefficient of variation was 7.2%. By comparison the coefficient of variation of Pdi during PImax. was 13.0% in seven subjects. The maximal sniff is a spontaneous manoeuvre, easily performed, repeatable without tiring, and reproducible. Its measurement provides a more reliable quantitative method for assessment of diaphragm strength, which has potential in clinical practice.

Adult↗
PubMed1985

Phosphorylation in vitro of Escherichia coli-produced 235R and 266R tumor antigens encoded by human adenovirus type 12 early transformation region 1A.

The tumor (T) antigens encoded by the human adenovirus early transforming region 1A (E1A) are gene regulatory proteins whose functions can immortalize cells. We have recently described the synthesis in Escherichia coli and the purification of the complete T antigens encoded by the adenovirus type 12 (Ad12) E1A 12S mRNA (235-residue [235R] T antigen) and 13S mRNA (266R T antigen). In this study, we show that the Ad12 E1A T antigens are extensively phosphorylated in Ad12-infected mammalian cells but are not phosphorylated in E. coli. Inasmuch as posttranslational phosphorylation at specific amino acid sites may be important for biological activity, we have studied the phosphorylation of the E. coli-produced T antigens in vitro by using a kinase activity isolated from cultured human KB cells. The kinase was purified about 300-fold and appears to be a cyclic AMP-independent, Ca2+-independent protein kinase requiring only ATP and Mg2+ for activity. To determine which amino acids are phosphorylated and whether phosphorylation in vitro occurs at the same amino acid sites that are phosphorylated in vivo, the Ad12 E1A T-antigen species synthesized by infected cells were metabolically labeled with 32Pi and compared with the E. coli-produced E1A T antigens labeled in vitro with [gamma-32P]ATP by using the partially purified kinase. Partial V8 proteolysis analysis gave similar patterns for in vivo- and in vitro-phosphorylated T antigen. Two-dimensional maps of tryptic phosphopeptides and of chymotryptic phosphopeptides suggested that mainly the same amino acid sites are phosphorylated in vitro and in vivo and that phosphorylation occurred at multiple sites distributed throughout the T-antigen molecule. Serine was the only amino acid that was phosphorylated both in vivo and in vitro, and, surprisingly, most serines appeared to be phosphorylated. The feasibility of faithfully phosphorylating T antigens in vitro suggests that the E. coli-produced Ad12 E1A 235R and 266R T antigens may prove useful for molecular studies on T-antigen function.

Adenoviruses, Human↗
PubMed1985

Assessment of bronchiectasis by computed tomography.

Computed tomography and bronchography were used to assess the distribution of bronchiectasis in 15 lungs from eight patients with clinical features of the disease. Of the 36 lobes adequately displayed by bronchography, 22 were found to have bronchiectasis and 14 were found to be normal by both techniques. Cystic disease was readily identified by computed tomography but the cylindrical and varicose types of bronchiectasis could not be distinguished. Segmental localisation was less accurate, with agreement between computed tomography and bronchography in 116 out of 130 segments. It is concluded that with a modern high resolution scanner computed tomography provides a useful method of assessing lobar distribution in bronchiectasis.

Bronchiectasis↗
PubMed1985

Effect of aminophylline on the human diaphragm.

The effect of intravenous aminophylline on the contractile function of the diaphragm was studied in four normal subjects. The contractility of the diaphragm was assessed by the measurement of transdiaphragmatic pressure (Pdi) after right phrenic nerve stimulation at 1 Hz. Pdi was measured before and during aminophylline infusion (6 mg/kg over 30 minutes), during which therapeutic concentrations of theophylline were attained (mean 13.8 mg/l, range 8.5-20.2). The Pdi achieved was not affected by aminophylline. This result suggests that theophylline at therapeutic concentrations has little effect on the contractility of the normal human diaphragm.

Adult↗
PubMed1985

Action of abdominal muscles on rib cage in humans.

To assess the actions of the rectus abdominis and external oblique muscles on the rib cage in humans, these two muscles were stimulated with surface electrodes in four normal supine subjects at functional residual capacity. Changes in anteroposterior and transverse rib cage diameters and changes in xiphipubic distance were measured with pairs of magnetometers. Stimulation of rectus abdominis produced a marked decrease in the xiphipubic distance and in the anteroposterior diameter, thus making the rib cage more elliptic. In contrast, stimulation of the external oblique caused a decrease in the transverse diameter, making the rib cage more cylindrical. When both muscles were stimulated simultaneously, the resultant rib cage distortion depended on the relative voltage at which each muscle was stimulated. Electromyogram recordings showed that there was no cross contamination or activity of the diaphragm during the muscle stimulations. Transdiaphragmatic pressure increased with the voltage of stimulation, suggesting passive lengthening of the diaphragm. X-ray studies were performed in two subjects and confirmed the main magnetometer findings. These studies thus confirm that the rib cage in humans is more easily distortable than conventionally thought. The abdominal muscles can distort it in either direction depending on which muscles are contracting.

Abdominal Muscles↗
PubMed1985

Oncogenes in laryngeal cancer: serial passage of transformed cellular DNA.

DNA originally extracted from squamous cell cancer of the larynx has been serially passaged through transformed populations of NIH/3T3 mouse fibroblasts. The transformed foci were then harvested, cloned to volume, and incubated with a fresh population of NIH/3T3 cells in a second passage. Transforming efficiencies were enhanced by serial passage. In addition, Southern Blot analysis of the transformed foci revealed hybridization between transformant DNA and human probe DNA from the Alu family of conserved human DNA sequences. In the first passage this hybridization took the form of diffuse homology throughout the entire molecular weight distribution. The second-passage DNA showed "narrow bands" indicating the possibility that an oncogene has been identified in laryngeal cancer and that serial passage has eliminated contaminating human sequences. Repetitive transfection in third- and fourth-passage studies is now being completed.

Animals↗
PubMed1985

Mental illness and the media: an assessment of attitudes and communication.

Media coverage of psychiatric issues will reflect or influence public perceptions of the mentally ill. In order to explore the relationship between psychiatry and the media, an attitudinal questionnaire was administered to a systematic sample of 20 reporters, 20 psychiatrists, 20 medical outpatients with no psychiatric history, and 40 psychiatric inpatients. In addition, 4 psychiatric patients who had personal experience with media coverage were interviewed to determine the impact. Their stories are presented as clinical vignettes. The results of the questionnaire survey show that media reporters are no less accepting of mental illness than the other groups. A regression analysis of attitudinal predictors elicit education as more significant than age and media exposure. Yet low scores for the coverage by the media of mental illness were given by all groups with psychiatrists tending to be most critical. Reasons offered by reporters included "sensationalism sells" along with cost and time factors. Recommendations for both reporters and psychiatrists groups were collated, aiming at improving communication and ensuring a more positive emphasis and greater accuracy of media coverage of mental health issues.

Adult↗
PubMed1985

Oncogenes: their presence and significance in squamous cell cancer of the head and neck.

DNA extracted from squamous cell carcinomas of the larynx and tongue has been shown to contain cellular transforming genes characterized by their ability to transform mouse fibroblasts into malignant foci of cells which, when subsequently cloned and grown to volume, have been found to contain human DNA sequences. This DNA has been serially passaged through subsequent populations of NIH/3T3 mouse fibroblasts. Higher malignant transformation efficiencies have been observed and reported with serial passage. Of greater significance is the repeated identification of oncogenes of identical characteristics on electrophoretic radioisotope analysis.

Carcinoma, Squamous Cell↗
PubMed1985

Fall in vital capacity with posture.

In a study of 147 subjects (50 normals, 50 with obstructive, and 47 with restrictive lung function), the mean reduction in forced vital capacity from standing to supine (delta FVC) was 7.5% (SD +/- 5.7), 11.2% (+/- 13.4), and 8.2% (+/- 7.7) respectively, with no significant difference between groups. The respective 95% upper confidence limits were 19%, 38% and 24%. We conclude that delta FVC greater than 25% associated with normal or restrictive lung function or greater than 35% associated with airways obstruction should be an indication for further study of diaphragm function.

Adult↗
PubMed1984

Unusual heterogeneity of the 5'-termini of human adenovirus type 2 early region E2 mRNA.

The 5'-terminal structures of human adenovirus type 2 (Ad2) early region 2 (E2) mRNA were investigated. The E2 transcription unit has several interesting properties, including the presence of a TATA-like box that matches the consensus sequence poorly, delayed transcription during early stages of infection, and a switch in promoter recognition late after infection. E2-specific RNA, 5'-labeled in vitro to high specific activity was analyzed. Purified E2 mRNA was digested with RNase A or RNase T1 and the resulting oligonucleotides were resolved by two dimensional paper electrophoresis-homochromatography. Remarkably, as many as sixteen 5'-terminal RNase A oligonucleotides were identified and their sequences were deduced. The most common 5'-termini in the RNase A digest were p(m6)AmCp, p(m6)AmA(m)Cp, pGmA(m)Cp, and p(m6)AmG(m)Cp. Two RNase A oligonucleotides originated from the E4 promoter region, consistent with electron microscopic observations. The sequence encoding these potential initiation sites covered about 90 nucleotides. Eleven of the sequences of the 5'-terminal RNase A oligonucleotides were aligned with the Ad2 DNA sequence in the Ad2 E2 promoter region. If the heterogeneous termini in the E2 promoter region were generated by a process of transcription initiation, their existence cannot be explained by stuttering of RNA polymerase II. This suggests that the transcription of Ad early region 2 has features which differ from those of other Ad2 early gene transcription units. Perhaps this is due to the absence of a conventional TATA box which is believed to position the initiation site. Alternatively, it is conceivable that the E2 promoter represents an alternate class of RNA polymerase II promoters containing different signals with different requirements for activation and/or that an E1A gene product modifies transcription initiation.

Adenoviruses, Human↗
PubMed1984

Developmental physiological optics and visual acuity: a brief review.

The development of optical and neural factors affecting visual acuity is reviewed with the aim of determining the age at which the relationship between optical and neural factors become mature. Delayed development of extrastriate cortical and indirect visual pathways may account for differences in acuity assessed by preferential looking and pattern reversal VEPs.

Adult↗
PubMed1984

Clinical efficacy and electrophysiologic effects of intravenous and oral encainide in patients with accessory atrioventricular pathways and supraventricular arrhythmias.

The electrophysiologic effects and clinical efficacy of intravenous (i.v.) and oral encainide were studied in 13 patients with accessory atrioventricular (AV) pathways (7 overt, 1 intermittent and 5 concealed) and drug-resistant supraventricular arrhythmias (5 paroxysmal atrial fibrillation, 1 atrial tachycardia and 7 with orthodromic circus movement tachycardia). Previously, therapy had failed with a mean of 3 conventional antiarrhythmic agents. In 5 patients, amiodarone administration had also been unsuccessful. All patients underwent programmed electrical stimulation of the heart before and after 1.5 mg/kg of i.v. encainide. Seven patients were restudied during oral encainide therapy (mean 155.8 +/- 54.2 mg/day) 3 days to 6 weeks (average 21 days) later. Anterograde conduction over the accessory AV pathway blocked in 4 of 7 patients after i.v. encainide. Oral encainide blocked anterograde conduction over the accessory pathway or prolonged the refractory period of the accessory pathway in 3 of 4 patients. This change in anterograde conduction was independent of the predrug value for the anterograde refractory period of the accessory AV pathway. Intravenous and oral encainide had minimal effects on retrograde conduction over the accessory AV pathway. The clinical effect of oral encainide was studied in 12 patients. Four patients responded to oral encainide and have been free of arrhythmia or side effects for 2 to 20 months (average 10.5). Encainide failed to prevent the clinical arrhythmia in 2 patients. In 4 patients with atrial arrhythmias, circus movement tachycardia developed during oral encainide therapy. In 1 patient the frequency of circus movement tachycardia increased with oral encainide treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗