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Biomedical subjects

J M Lewis

Publications and source records attributed to J M Lewis.

At least 127 records · Page 7Linked to original sources
PubMed1986

Initial laboratory evaluation of infants with 'presumed near-miss' sudden infant death syndrome.

We reviewed the cases of 201 infants hospitalized for "presumed near-miss" sudden infant death syndrome over a recent five-year period to determine the value of routine initial laboratory investigations in establishing diagnosis or altering therapy. A total of 1,278 measurements were performed on 163 patients aged 3 days to 6 months; 276 (22%) of the results were outside the normal limits for age. The most common abnormalities were hyperchloremia (58% of infants tested), hypermagnesemia (43%), hypobicarbonatemia (33%), and hyperkalemia (27%). There were no instances of polycythemia, hypochloremia, hypokalemia, hyperbicarbonatemia, or uremia. Only six (0.5%) of the abnormal values in four patients were useful in diagnosing or treating the apneic episodes. Infants with respiratory symptoms at the time of presentation had a statistically greater incidence of abnormal values than patients who were asymptomatic. Because of the low yield of useful information, we conclude that the use of a routine battery of laboratory investigations in the initial evaluation of infants with presumed near-miss sudden infant death syndrome should be questioned.

Electrolytes↗
PubMed1986

Quantitative analysis of thallium-201 uptake and washout before and after transluminal coronary angioplasty.

Transluminal coronary angioplasty has become an important therapeutic modality in the treatment of coronary artery disease. The effects of coronary angioplasty on regional myocardial perfusion have been reported in only a small series of patients, employing subjective analysis of thallium-201 perfusion scintigrams. Thus, we studied 61 patients with quantitative analysis of thallium-201 uptake and washout before and after undergoing angioplasty. Prior to angioplasty, there were 105 areas in 47 patients with abnormal thallium-201 uptake during exercise, with a mean uptake of 49 +/- 1.3%. The uptake of thallium-201 in these same areas increased to 71.3 +/- 1.9% post angioplasty (P less than 0.0001), and 68 (65%) of the areas showing abnormal uptake returned to normal. Abnormalities in washout of thallium-201 before angioplasty were seen more frequently than in uptake (150 vs 105 areas, P less than 0.05), with 8 patients having abnormal washout in the presence of totally normal uptake. Thallium-201 washout in the abnormal areas improved from 16 +/- 2.8 pre angioplasty to -23 +/- 1.8% post angioplasty (P less than 0.001). Normalization resulted in 6 of the 8 patients with exclusively washout abnormality. Residual abnormalities in uptake and/or washout were seen in 53% of the patients, usually in areas with prior myocardial infarction or supplied by a vessel with significant stenosis which did not undergo angioplasty. Improved thallium-201 uptake and washout corresponded to reductions in percent coronary area stenosis (89 +/- 1.0 to 36 +/- 2.0%, P less than 0.001) and transstenotic pressure gradient (42 +/- 3.0 to 9.0 +/- 2.0 mm Hg, P less than 0.001). Thus, quantitative analysis of thallium-201 uptake and washout provided objective evidence for improved myocardial perfusion after coronary angioplasty. Due to a fairly high prevalence of residual perfusion abnormalities after this procedure, optimal assessment of benefits requires quantitative comparison of thallium uptake and washout before and after coronary angioplasty.

Adult↗
PubMed1986

Family structure and stress.

This report presents an evolving theoretical model of the relationship between normative and severe stresses and a family's organizational structure. It is useful for understanding these processes and for planning treatment intervention for families at several levels of function: competent, dominant-submissive, chronically conflicted, and severely disturbed.

Dominance-Subordination↗
PubMed1985

Effects of transluminal coronary angioplasty on left ventricular systolic and diastolic function at rest and during exercise.

The left ventricular global and regional systolic function, ventricular volumes, and peak diastolic filling rate (PDFR) were studied in 30 patients with coronary artery disease, before and 2 to 5 days after transluminal coronary angioplasty (PTCA), utilizing equilibrium radionuclide angiography at rest and during exercise. At rest, the global ejection fraction (EF) was unchanged before (60 +/- 9%) and after PTCA (62 +/- 10%). During exercise, global EF increased from 59 +/- 11% pre PTCA to 67 +/- 10 post PTCA (p less than 0.001). Twenty-two patients had abnormal EF response to exercise pre PTCA, versus seven post PTCA (p less than 0.001). Improvements in exercise regional EF paralleled the changes in global EF. End-systolic volume was unchanged at rest but decreased significantly with exercise post PTCA (60 +/- 36 ml pre vs 49 +/- 32 ml post PTCA, p less than 0.01). At rest, the PDFR was unchanged post PTCA (2.4 +/- 0.9 end-diastolic volume (EDV)/sec pre vs 2.5 +/- 0.8 EDV/sec post). During exercise, PDFR increased from 2.1 +/- 0.7 EDV/sec pre PTCA to 2.5 +/- 0.7 EDV/sec post PTCA (p less than 0.02). In conclusion, in patients with coronary artery disease, successful PTCA improves global and regional systolic function during exercise. Diastolic function is improved during exercise, a fact not previously demonstrated.

Adult↗
PubMed1984

Continuous naloxone infusion in pediatric narcotic overdose.

A 31-month-old girl required constant intravenous (IV) infusion of naloxone hydrochloride to treat codeine-induced respiratory and CNS depression. The infusion rate was 0.4 mg/hr (27 micrograms/kg/hr) over nine hours, without apparent side effects or evidence of toxic effects, for a total naloxone hydrochloride dose of 4.1 mg (280 micrograms/kg). Constant naloxone hydrochloride infusion at an initial rate of 0.4 mg/hr in pediatric narcotic poisoning should be considered if the patient responds inadequately to an initial 0.01-mg/kg bolus, requires repeated administration to reverse narcotic-induced effects, or has ingested long-acting agents. Continuous IV naloxone infusion is a convenient, safe, and effective method to treat narcotic overdose.

Acetaminophen↗
PubMed1984

Skin stress and blood flow in sitting paraplegic patients.

Sitting paraplegic subjects, tested on a hard seat at a location 2 to 3cm lateral to the ischial tuberosities, develop roughly the same median pressure values (range 52 to 60mmHg) as groups of normal subjects and hospitalized geriatric patients. However, median paraplegic and hospitalized geriatric shear values are roughly three times median normal values. Median rates of pulsatile skin blood flow volumes for sitting paraplegic subjects, while roughly equal to those of hospitalized geriatric subjects, are only one third those of comparable normal subjects.

Adult↗
PubMed1983

A blood analogue for the experimental study of flow-related thrombosis at prosthetic heart valves.

It is shown that a flowing mixture of unpasteurised cow's milk, rennet and calcium chloride will deposit solid clot in vitro in the neighbourhood of certain kinds of flow obstruction and hydrodynamic disturbance particularly associated with deposition and thrombus formation in a similar stream of blood. The milk and blood deposits are similar in physical structure, both on a microscopic and a gross scales. For established kinds of artificial heart valves, the growth sequence and developed patterns of milk clotting obtained in vitro with pulsatile flows at physiological rates closely resemble patterns of thrombus reported clinically for valves of the same type in vivo. It appears that these phenomena, for which a tentative explanation is outlined, can form the basis of a convenient and rapid experimental method for evaluating in vitro the effects of design changes on the thrombogenicity of artificial heart valves and other cardiovascular devices in vivo. The milk system also shows promise as an aid in fundamental experimental studies of mechanisms of flow-related thrombosis.

Animals↗