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Biomedical subjects

P Norris

Publications and source records attributed to P Norris.

At least 55 records · Page 3Linked to original sources
PubMed1990

Allergic contact dermatitis to adhesive bandages.

More than two billion Band-Aid Brand Sheer Strips are used in the United States yearly, yet allergic contact dermatitis resulting from their use is nearly nonexistent. We report four patients with allergic reactions to these strips. One patient reacted to tricresyl phosphate, the plasticizer in the vinyl backing; another patient was allergic to 2,5-di(tertiary-amyl)hydroquinone, the antioxidant in the adhesive. In the other two patients, the allergic contact dermatitis remains unexplained.

Adhesives↗
PubMed1988

Escherichia coli O157:H7, an emerging gastrointestinal pathogen. Results of a one-year, prospective, population-based study.

To examine the incidence of Escherichia coli O157:H7 enteric infections in the United States and to evaluate the vehicles of transmission for sporadic cases, we conducted a one-year, population-based study at a large health maintenance organization (HMO) in the Puget Sound area of Washington State. All stool specimens submitted for culture to the HMO laboratory were screened for E coli O157:H7; the organism was identified in 25 (0.4%) of 6485 stool specimens. All patients with E coli O157:H7 identified had diarrhea; 24 patients (96%) had bloody diarrhea. Exposure histories demonstrated that rare ground beef was consumed more often by patients (21%) than by age-matched control subjects (4%) in the week before onset of illness. Raw milk also was consumed by two patients but by none of the control subjects. Incidence rates for laboratory-confirmed enteric infections in the HMO population were as follows: Campylobacter, 50/100,000 person-years; Salmonella, 21/100,000 person-years; E coli O157:H7, 8/100,000 person-years; and Shigella, 7/100,000 person-years. The organism is a more common pathogen in the United States than is generally recognized, and the diagnosis should be considered for patients with suspected enteric infection.

Adolescent↗
PubMed1988

Zinc chelatase in human lymphocytes: detection of the enzymatic defect in erythropoietic protoporphyria.

We describe a fluorometric assay for heme synthetase, the enzyme that is genetically deficient in erythropoietic protoporphyria. The method, which can readily detect activity in 1 microliter of packed human lymphocytes, is based on the formation of zinc protoheme from protoporphyrin IX. That zinc chelatase and ferrochelatase activities reside in the same enzyme was shown by the competitive action of ferrous ions and the inhibitory effects of N-methyl protoporphyrin (a specific inhibitor of heme synthetase) on zinc chelatase. The Km for zinc was 11 micrograms and that for protoporphyrin IX was 6 microM. The Ki fro ferrous ions was 14 microM. Zinc chelatase was reduced to 15.3% of the mean control activity in lymphocytes obtained from patients with protoporphyria, thus confirming the defect of heme biosynthesis in this disorder. The assay should prove to be useful for determining heme synthetase in tissues with low specific activity and to investigate further the enzymatic defect in protoporphyria.

Erythropoiesis↗
PubMed1988

Polymorphonuclear leukocyte random migration and chemotaxis in psoriatic and healthy adult smokers and non-smokers.

Random migration and chemotactic responsiveness of polymorphonuclear leukocytes (PMNs) from psoriatic and control smokers and non-smokers were studied in vitro and in vivo. In vivo, but not in vitro, PMNs from psoriatic smokers responded to a significantly greater degree to a standard chemotaxin than did PMNs from psoriatic non-smokers, control smokers and control non-smokers. This suggests that smoking has a selective effect on psoriatic PMNs. The possible relevance of this to the pathogenesis of psoriasis vulgaris and to palmoplantar pustulosis is discussed.

Adolescent↗
PubMed1986

Biofeedback, voluntary control, and human potential.

This paper examines some of the philosophical and scientific relationships involving self-control, voluntary control, and psychophysiologic self-regulation. The role of biofeedback in mediating conscious and unconscious processes is explored. Demonstrations of superior voluntary control and its relationship to belief, confidence, and expectation are examined. Biofeedback demonstrates the potential of control to oneself, creating confidence in one's ability to establish enhanced and peak performance in athletics, education, and psychophysiologic therapy. Emphasis is placed on the power of images in all human functioning, and in enhancing human potential.

Biofeedback, Psychology↗
PubMed1986

Biobehavioral treatment of essential hypertension: a group outcome study.

In a group outcome and follow-up study of 77 patients with essential hypertension, significant reductions were seen in systolic and diastolic blood pressure (BP) and in hypotensive medication requirement. A multimodality biobehavioral treatment was used which included biofeedback-assisted training techniques aimed at teaching self-regulation of vasodilation in the hands and feet. Of the 54 medicated patients, 58% were able to eliminate hypotensive medication while at the same time reducing BP an average of 15/10 mm Hg. An additional 19 (35%) of the medicated patients were able to cut their medications approximately in half while reducing BP by 18/10 mm Hg. The remaining 4 (7%) medicated patients showed no improvement in either BP or medication requirement. Similar reductions in BP were seen in initially unmedicated patients. Seventy percent of the 23 unmedicated patients achieved average pressures below 140/90 mm Hg, with an additional 22% of these patients making clinically significant reductions in pressure without becoming normotensive, and with 8% unsuccessful at lowering pressures to a clinically significant extent. Follow-up data available on 61 patients over an average of 33 months indicated little regression in these results with 51% of the total patient sample remaining well-controlled off medication, an additional 41% partially controlled, and 8% unsuccessful in lowering either medications and/or blood pressures to a clinically significant extent.

Adult↗
PubMed1984

Democratic consensus and the young: a cross national comparison of Britain and America.

In previous decades research has suggested that the young, especially those in higher education, were increasingly cynical , distrustful and disenchanted with the democratic process in Britain and America. The aim of this paper is to see how far this is still the case by assessing democratic attitudes amongst college students in a sample from Britain and America, using scales developed by McClosky (1964). The paper concludes that the responses from the American and British sample were fairly similar across a number of scales on the rules of the game, free speech and equality. On all these both groups of students displayed relatively high support for democratic attitudes. The main contrast was found on feelings of trust and efficacy, with the British sample showing much lower feelings that government was honest and responsive to their needs. The paper concludes with some suggestions about how these responses can be explained.

Adolescent↗
PubMed1983

Use of the cryostat section in electron microscopy.

A method using the cryostat section as a source of material from which relevant areas for ultrastructural examination can be positively located and quickly processed is described. Preservation of the tissue does not appear to be unduly affected by freezing and subsequent cryostat sectioning.

Animals↗
PubMed1980

Laryngeal and diaphragmatic responses to airway occlusion in sleep and wakefulness.

Under anesthesia, electrodes were implanted in 5 adult cats for chronically recording sleep parameters. In the same operation, a tracheal fistula was created that allowed tracheal intubations for recordings of breathing (pneumotachography) and tracheal occlusions in subsequent experiments conducted during the spontaneous sleep-waking cycle. After a recovery period of at least 3 months, electrodes were placed, under ether anesthesia, in the laryngeal abductors. Two days later, electrodes were inserted into the diaphragm, and the responses of the diaphragm and laryngeal abductor muscles to airway occlusion in sleep and wakefulness were studied. Total airway occlusion at end-expiration in NREM sleep caused a progressive augmentation of both laryngeal adductor and diaphragmatic activity. Increases in laryngeal abductor activity exceeded for increases in diaphragmatic activity. The greatest augmentations between one breath and the next were seen when occluded breath "n" occurred in sleep and occluded breath "n + 1" occurred in wakefulness. This augmentation of activity at the transition from sleep to wakefulness was greater for the laryngeal abductors than for the diaphragm, and it signifies an immediate wakefulness stimulus to the response to an occlusion. Occlusions in REM sleep caused a variable augmentation in laryngeal inspiratory activity, but, across animals, there was no clear augmentation of either tonic (expiratory) laryngeal abductor or diaphragmatic activity. In addition, arousal in response to occulusion was delayed in REM sleep.

Airway Obstruction↗
PubMed1979

Experimental control of the diaphragm and laryngeal abductor muscles by brain stem arousal systems.

The effect of mesencephalic central tegmental field (FTC) stimulation in barbiturate anesthetized cats on the activity of the diaphragm and the laryngeal abductors was studied. With brief stimulus trains, two effects were observed: (1) a short latency, stimulus-specific activation of these muscles and (2) phase-switching of the respiratory cycle. The characteristics of short latency driving were as follows: (1) the latency and threshold for activation of the laryngeal abductors was less than for activation of the diaphragm; (2) driving continued for the duration of the stimulus only; and (3) during expiration, the threshold for short latency driving was lowest in the early part of the phase and progressively increased throughout it. Phase-switching had these characteristics: (1) expiration-to-inspiration (E-to-I) phase-switching was obtained in all cases and, in 17% of the cases, stimulation of the same FTC site also produced I-to-E phase-switching; (2) phase-switching was a function of stimulus intensity and the time of stimulation; and (3) during expiration, phase-switching showed a threshold profile opposite to that for short latency driving. These effects could be obtained after bilateral dorsolateral pontine lesions, bilateral vagotomy, and transection at the C8 level. It was concluded that the FTC could influence breathing by two systems. One is relatively direct to respiratory motoneurons and the other engages the oscillator.

Animals↗
PubMed1977

The fine structure of human macrophage granules in sarcoidosis.

Human macrophages in the lesion of sarcoidosis contain cytoplasmic granules with an ordered paracrystalline substructure. Similar though less ordered granules are seen in human macrophages elsewhere. These appearances as well as the general ultrastructure of the cell are compatible with the view that these macrophages have a secretory function.

Cytoplasmic Granules↗
PubMed1976

Toxicity and accumulation of thallium in bacteria and yeast.

Thallium sulphate inhibited microbial growth, with Bacillus megaterium KM more sensitive to the metal than Saccharomyces cerevisiae and Escherichia coli. Inhibition of B. megaterium KM and S. cerevisiae, but not of E. coli, was alleviated by increasing the potassium concentration of the medium; inhibition of respiration of S. cerevisiae, but not of E. coli, was similarly alleviated. Thallium was rapidly bound, presumably to cell surfaces, by S. cerevisiae and E. coli, and was progressively accumulated by energy-dependent transport systems (probably concerned primarily with potassium uptake) with both organisms. Thallium uptake kinetics suggested more than one transport system operated in yeast, possibly reflecting a multiplicity of potassium transport systems. Apparent Km and Ki values for competitive inhibition of thallium uptake by potassium indicated S. cerevisiae to have a higher affinity for thallium uptake than for potassium, while E. coli had a transport system with a higher affinity for potassium than for thallium. The likely systems for thallium transport are discussed. A mutant of E. coli with tenfold decreased sensitivity to thallium was isolated and apparently effected surface binding of thallium in amounts equivalent to the wild type organism, but showed no subsequent uptake and accumulation of the metal from buffer, even though it was able to accumulate potassium to normal intracellular concentrations during growth.

Bacillus megaterium↗
PubMed1976

The fine structure of neoplastic invasion: invasion of liver, skeletal muscle and lymphatic vessels by the Rd/3 tumour.

Neoplastic invasion as seen in the rat Rd/3 neoplasm has been studied electron microscopically in three sites: abdominal wall, footpad and liver. This neoplasm invades by peripheral cell division and active cell migration. Neoplastic cells protrude many fine processes and compress host cells. Neoplastic cells invade lymphatic vessels in a way similar to that in which white blood cells penetrate them - by the protrusion of fine cytoplasmic processes and passage, sometimes in clumps through open cell junctions. There is no ultrastructural evidence of secretory phenomena.

Abdominal Muscles↗