Biomedical subjects
M Newton
Publications and source records attributed to M Newton.
Amniotic fluid embolism: the nonfatal case.
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Potential exposure of humans to 2,4,5-T and TCDD in the Oregon coast ranges.
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Professional image: enhanced or inhibited by attire?
Nursing faculty have expressed concern about inappropriate dress of students and staff in the clinical setting. The researchers developed and administered a Likert-type questionnaire to faculty and students from 50 randomly selected, National League for Nursing-accredited baccalaureate nursing programs. The perceptions of professional attire of students and faculty were compared and analyzed. The tool assessed effects of demographic variables, such as age, gender, and curriculum level. In addition, questions assessed subject's opinions about attire options such as jumpsuits, "scrubs," tee-shirts, sweatshirts, hemlines, traditional white uniform, street clothes, hair length, jewelry, and nail length. Attire preferences significantly correlated with faculty age and teaching level. The older faculty preferred more traditional attire, and faculty in the upper division of the curriculum preferred more nontraditional attire. This same correlation was found for older students and for students enrolled in the upper division. Faculty influence on students' perceptions of attire was also addressed. Students reported that faculty positively influenced their perceptions of professional image. Students also believed that faculty were professionally attired in the classroom and clinical setting.
Primary structure of Torpedo californica acetylcholinesterase deduced from its cDNA sequence.
Acetylcholinesterase, an essential enzyme of the nervous system, rapidly terminates the action of acetylcholine released into the synapse. Acetylcholinesterase is also found (in lower abundance) in extrajunctional areas of muscle and nerve and on erythrocyte membranes. Hydrodynamic analyses of the native enzyme and characterization of its dissociated subunits have revealed multiple enzyme forms which can be divided into two classes: dimensionally asymmetric forms which are usually found within the synapse and contain a collagen-like structural subunit disulphide-linked to the catalytic subunits; and globular forms which appear to be widely distributed on the outer surface of cell membranes. Both forms have been characterized in the ray Torpedo californica and, although their catalytic behaviours seem to be identical, they differ slightly in amino-acid composition, peptide maps and reactivity with certain monoclonal antibodies. Here, we report the complete amino-acid sequence of an acetylcholinesterase inferred from the sequence of a complementary DNA clone. The 575-residue protein shows significant homology with the C-terminal portion of thyroglobulin.
Characterization of an expressed CD3-associated Ti gamma-chain reveals C gamma domain polymorphism.
The majority of human T cells express an antigen receptor consisting of a disulphide-linked heterodimer (Ti) of relative molecular mass 80,000-90,000 (Mr 80-90K) which is noncovalently associated with a set of at least three proteins of Mr 20-28K termed CD3 (Leu4, T3). Whereas both chains of Ti, an acidic alpha-chain of Mr 48-54K and a more basic beta-chain of Mr 40-44K, contain variable and constant region domains, the component peptides of CD3 are invariant. Several laboratories have more recently reported the expression of CD3 in association with a novel protein. On the surface of long-term T-cell lines and one thymocyte clone this novel structure consists of a 40K protein noncovalently linked to a 55 or 62K protein identified as the protein product of the Ti gamma-chain gene, a T-cell specific gene which like the Ti alpha- and Ti beta-chain genes undergoes rearrangement of variable (V) and joining (J) region gene segments. On the human T-cell leukaemic line PEER we have detected only a single 55K glycoprotein associated with CD3. We here demonstrate that an anti-Ti gamma-peptide antiserum reacts with the 55K CD3-associated protein on PEER. Most previously described human Ti gamma-chain complementary DNA clones encode the products of non-functional rearrangements. One of the Ti gamma cDNAs isolated from PEER, however, represents a functional rearrangement reported for the first time in a cell which expresses a Ti gamma-chain protein product on the cell surface. Interestingly, a 48-base-pair (bp) sequence in the constant (C) region domain of this functional Ti gamma-chain cDNA is triplicated in PEER and duplicated in other cDNAs isolated from PEER and other cell lines.
Renal lithium reabsorption in man: physiologic and pharmacologic determinants.
In order to evaluate the premise that renal lithium reabsorption may reflect proximal tubular sodium reabsorption, the fractional excretion of lithium (FELi) was measured, during a variety of experimental maneuvers known to affect renal cation reabsorption, in normal volunteers who had been pre-loaded with lithium. Furosemide increased FELi, as well as sodium, calcium, and magnesium excretion, during the first hour following diuretic administration. Subsequently, sodium, calcium, and magnesium excretion continued to remain elevated after furosemide, despite progressive volume depletion, but FELi values usually declined at least to pretreatment levels. Oral glucose ingestion increased lithium, calcium, and magnesium excretion while sodium and potassium excretion decreased concomitantly. Increases in FELi during volume expansion with saline were correlated with changes in fractional flow (V/GFR) in natriuretic subjects. Parathyroid extract (PTE) increased both FELi and fractional phosphate excretion (FEphos). FELi and FEphos were correlated significantly in the studies with furosemide and PTE, but not after saline volume expansion. In persons who previously had undergone unilateral nephrectomy, FELi was not increased over values in normal subjects. These results indicate that changes in lithium reabsorption may be dissociated from the reabsorption of other cations. They are consistent with the hypothesis that FELi may reflect proximal tubular sodium rejection, but do not exclude other more distal sites of lithium reabsorption.
Catecholamine, renin, aldosterone, and arginine vasopressin responses to lower body negative pressure and tilt in normal humans: effects of bromocriptine.
We have examined the effects of the dopamine agonist bromocriptine (BEC) on the hormonal and hemodynamic response to graded lower body negative pressure (LBNP) and tilting in five normal volunteers. BEC blunted the plasma norepinephrine (NE), plasma renin activity (PRA), and aldosterone responses to both LBNP and tilting. The inhibitory effects of BEC on the plasma NE response to these maneuvers are likely mediated through presynaptic inhibition of peripheral neuronal release of NE as well as central nervous system effects of the drug. Since the PRA responses to LBNP and tilting are likely mediated through beta-adrenoreceptor stimulation, BEC probably indirectly blunts the PRA and aldosterone responses to those maneuvers through its inhibitory effects on NE secretion. BEC treatment resulted in a hypotensive response to tilting that was accompanied by a rise in plasma potassium and arginine vasopressin (AVP). No such rises in plasma potassium and AVP are observed, in the absence of BEC treatment, following graded LBNP and tilting. The rise in plasma potassium with tilting (BEC treatment) probably resulted from blunting of the NE rise. Thus, the rise in plasma NE may play an important role in preventing a rise in plasma potassium in association with LBNP and orthostatic stress. AVP levels in normal men are not responsive to unloading of cardiopulmonary and sinoaortic baroreceptors. It is only after overt hypotension is produced--as after BEC treatment--that plasma levels of AVP rise.
Renewal--a positive outcome of faculty evaluation.
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The growth of a nursing specialty.
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The role of the obstetric, gynecologic, and neonatal nurse. Results of two NAACOG surveys.
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Gastric compliance, sensation, and the relaxation response to a nitric oxide donor in health and reflux oesophagitis.
BACKGROUND/AIMS: The gastric fundus affects afferent control of lower oesophageal sphincter function. Nitric oxide is an important relaxant of the fundus. We postulated that gastric distensibility, compliance and nitric oxide sensitivity may be altered in patients with gastro-oesophageal reflux disease (GERD). METHODS: 9 patients with erosive oesophagitis (6 males; median age 55 years) and 16 healthy controls (9 males; median age 36 years) were studied fasting with a gastric barostat. Minimal distending pressure (MDP) and gastric compliance (Deltav/Deltap) were determined by increasing intrabag pressure in 2-mm Hg increments. The pressures required to produce initial sensation and maximum tolerated sensation were recorded. With the intrabag pressure set at MDP +2 mm Hg, 500 microg sublingual glyceryl trinitrate was administered and the percentage change in intrabag volume from initial volume recorded. RESULTS: The MDP was significantly greater in patients than controls (7.5 vs. 6.7 mm Hg median; p = 0.02). Gastric compliance was similar in both groups (57.8 vs. 67.2 ml/mm Hg; p = 0.4). There was no difference between groups in the pressure at first intragastric sensation (11.2 vs. 10.3 mm Hg above MDP; p = 0.5) or in the maximal tolerated pressure (15.8 vs. 14.3 mm Hg above MDP; p = 0.2). The proportional change in gastric volume from baseline in response to glyceryl trinitrate was smaller in patients than controls (66 (3-200) vs. 120 (26-1,053)%; p = 0.02). CONCLUSIONS: Gastric MDP may be altered in GERD, but gastric compliance and sensitivity to distension are normal. Major gastric relaxation occurs in response to a nitric oxide donor, but this appears to be diminished in patients with GERD. Upper gut nitrinergic mechanisms may be altered in oesophageal reflux disease.
Wound care. What a relief measure.
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Editorial: Gynecologic-oncology nursing.
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Prostate screening health beliefs and practices of African American men.
The purpose of this study was to investigate the health beliefs and practices of African American men regarding prostate cancer screening. A descriptive non-experimental design was used with a self-administered questionnaire to identify participants' knowledge level, health beliefs and practices related to the screening and early detection of prostate cancer in African American men. Results indicate that most participants had a high level of prostate cancer knowledge, early detection and had prostate screening done on a regular basis. They believed prostate cancer was not preventable but if contracted treatment would be painful and impair sexual function. Other significant beliefs included: good health habits were important, most rated their health as good or excellent, and they rely on their faith to stay healthy. Findings of this study provide culturally appropriate information which may contribute to developing prostate cancer prevention programs in African American communities.
Contrast injection bradycardia during coronary angiography: effects in the denervated human heart.
To assess the contribution of cardiac innervation toward understanding the mechanisms of bradycardia during contrast coronary angiography, heart rate (HR) responses in eight patients after heart transplantation were compared with 10 normal patients (control), 10 patients with coronary artery disease (CAD) and normal ventricular function, and 10 patients with congestive cardiomyopathy and normal coronary arteries. The longest P-P interval was measured beat to beat before (HR 1) and after (HR 2) coronary angiography. The coronary vessel perfusing the sinus node did not influence HR 2 responses within each group. HR 1 was significantly different from HR 2 (p less than 0.05) in the control and CAD groups but was not different in the transplant and cardiomyopathy groups. Compared with the control group, the percent decrease in HR was significantly less in transplant patients than in patients with cardiomyopathy. Thus contrast injection bradycardia is absent in denervated patients after heart transplant, and this response is markedly blunted in cardiomyopathy patients who are known to have diminished vasodepressor reflexes. These findings suggest that the bradycardia response is probably a neurally mediated phenomenon.