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Biomedical subjects

J M Lewis

Publications and source records attributed to J M Lewis.

At least 109 records · Page 6Linked to original sources
PubMed1988

Clinical significance of perfusion defects by thallium-201 single photon emission tomography following oral dipyridamole early after coronary angioplasty.

The clinical significance of myocardial perfusion defects present early after angiographically successful percutaneous transluminal coronary angioplasty was assessed in 53 patients using thallium-201 single photon emission computed tomography combined with pharmacologic vasodilation induced by a large dose (300 mg) of orally administered dipyridamole. Myocardial tomographic images were obtained at a mean of 20 +/- 6 h (SD) before and 2.9 +/- 2.7 days after angioplasty. Before angioplasty, 15 (28%) of the 53 patients developed angina after dipyridamole administration, in contrast to only 3 (7.5%) of 40 patients after angioplasty (p less than 0.001). The mean percent luminal area stenosis decreased from 93 +/- 6% before angioplasty to 34 +/- 17% after angioplasty (p less than 0.001). Myocardial perfusion defects, present in 49 (93%) of the 53 patients before angioplasty, were reversible in 44 patients (83%), all of whom underwent dilation of arteries supplying the ischemic areas. After angioplasty, 26 (65%) of 40 patients had no ischemic defects, whereas 14 (35%) of the patients still had an ischemic defect in the vascular territory of the dilated artery. After a mean follow-up period of 21.7 months, 13 (33%) of 39 patients developed restenosis, 10 of whom had an ischemic defect early after angioplasty. Restenosis developed in 10 (71%) of 14 patients with an ischemic defect after angioplasty, but in only 3 (11.5%) of the patients without an ischemic defect (p = 0.007). In conclusion, thallium-201 tomography after oral dipyridamole affords convenient assessment of the physiologic significance of coronary stenosis present before angioplasty and the residual stenosis after angioplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1988

Augmentation blepharoplasty.

Conventional lower lid blepharoplasty techniques emphasize the removal of excess skin and fatty bulges of the lower eyelid. The appearance is improved at the expense of lateral pretarsal flatness associated with the senile eyelid. Augmentation blepharoplasty is a modified technique for a lower lid blepharoplasty using an overlapping orbicularis oculi muscle repair to increase pretarsal fullness, which is associated with the youthful lower eyelid. The technique was used successfully in 30 consecutive, unselected patients, and this experience is reviewed in detail. The technique, surgical anatomy, and complications are outlined. The results prove this technique to be a safe method of lower lid blepharoplasty that does not interfere with the additional goals of periorbital fat and excess skin removal.

Adult↗
PubMed1988

The transition to parenthood: I. The rating of prenatal marital competence.

This article is the first of three that will present data from the Timberlawn Psychiatric Research Foundation Young Family Project, a study of the development over time of competent family systems. The Project is briefly described and findings are presented from the initial data collection period. The operational definitions of marital competence and the Continuum of Marital Competence are presented, and the data are interpreted to suggest that the spouses' levels of individual psychological health, their agreement on values, and their socioeconomic status are related to the level of marital competence. The level of prenatal marital competence at Time 1 is used as an independent variable with which to predict both changes in marital structure and incorporation of the child into the family system at 3 months and 1 year postpartum. The results of these analyses will be presented in two subsequent articles.

Adolescent↗
PubMed1988

The transition to parenthood: II. Stability and change in marital structure.

At 1 year postpartum, 22 of 38 couples demonstrated the same level of marital competence as they had prenatally, 14 couples demonstrated deterioration in their marital relationship, and 2 couples were improved. At each of four levels of marital competence, there was a trend for the couples to demonstrate the same relationship response to parenthood. Highly competent relationships remained at high levels of competence. Competent but pained relationships were most vulnerable to regressive change in structure. Dominant-submissive, complementary relationships tended to remain stable at that level. Dominant-submissive, conflicted or severely conflicted relationships were most unpredictable and stability, regression, and improvement were seen. These findings are explored for possible correlations and are discussed from the perspective of several current models of family development.

Dominance-Subordination↗
PubMed1988

The transition to parenthood: III. Incorporation of the child into the family.

The major focus of this article is the relationship of the parents' marital relationship structure to the incorporation of the child into the family. Our central hypothesis is that couples who have evolved more competent marital structures prenatally are more likely to incorporate the child successfully into the family.

Birth Order↗
PubMed1988

The practice of dentistry by male and female dentists.

Increasing numbers of women are entering the once male-dominated dental profession in Australia. Determining what differences exist in the practice of dentistry between male and female dentists has therefore become an important task. The purpose of the present study was to examine differences in practice between male and female dentists. Data were available from a weighted, stratified random sample of 730 dentists (486 male and 294 female dentists) in each State or Territory of Australia. Using discriminant analysis age, practice setting, number of other dentists in the practice, inputs to the practice of dentistry either hired, acquired or contributed, direct demand and community size were all found significant in separating male and female dentists. It was more difficult to separate younger male and female dentists, indicating some convergence between the sexes. However, some differences persisted. Possible reasons for the differences are discussed and some implications noted.

Adult↗
PubMed1987

In vivo assessment of vascular dilatation during percutaneous transluminal coronary angioplasty.

Previous studies of the mechanism of percutaneous transluminal coronary angioplasty used either postmortem specimens or animal models. To characterize the process of vascular dilatation in vivo, a system was devised for recording the instantaneous pressure-volume changes in the angioplasty balloon during inflation within the stenosed artery. The pressure-volume patterns obtained were compared with those observed in vitro with the balloon inflated in materials whose properties simulate stretching (Silastic tubing), compaction (styrofoam) and cracking (dry macaroni). Of 48 narrowings in 46 patients, a pressure-volume pattern of stretching was observed in 56%, compaction in 27% and cracking in only 17%. Of lesions manifesting a stretching pattern, 85% were longer than 5 mm cr had visible calcium deposits, whereas those that compacted were shorter and lacked calcium deposits. Both of these pressure-volume patterns were associated with a successful clinical outcome. Of 8 lesions exhibiting a cracking pattern, 6 showed dissection angiographically; 3 of these resulted in vessel occlusion.

Angioplasty, Balloon↗
PubMed1987

Digital visual acuity test using calculator-type numerals with geometric gradation.

The authors have developed a visual acuity test using numeric optotypes with dimensions similar to numerals used in liquid crystal displays (LCDs) or light-emitting diodes (LEDs). Each optotype has the same external configuration to minimize variation in recognition difficulty. The test is designed with geometric gradation and an equal number of optotypes per line, which facilitates the recording of acuity in decimal notation. This allows convenient data entry and computer analysis of acuity results. Chart inversion provides greater flexibility by altering the numeric sequence. This new digital acuity test (DAT) compares favorably to acuity tests that have Sloan or Snellen letters as optotypes.

Humans↗
PubMed1987

Pediatric residency guidelines for management of status epilepticus.

We reviewed 21 protocols for the evaluation and treatment of status epilepticus currently in use in pediatric residency programs. Guidelines were compared to determine variations in the recommendations for initial patient assessment, choice of anticonvulsant therapy, and instructions for medication administration. There was wide variation in recommendations for patient stabilization procedures and laboratory measurements. Fifteen different sequences of anticonvulsant administration were listed. The initial drug of choice was intravenous diazepam in 81% of the programs, in doses ranging from 0.1 to 0.75 mg/kg. The preference for the second-line anticonvulsant was divided equally between phenytoin and phenobarbital. Phenytoin was not mentioned at all in three (14%) of the protocols, while paraldehyde was included in 14 (66%). Instructions for paraldehyde administration were confusing, imprecise, and occasionally inappropriate. We conclude that there is no well-accepted approach to the management of status epilepticus in pediatric patients. Furthermore, the guidelines in current use frequently are incomplete and probably confusing to residents.

Child↗
PubMed1987

Persistent isolated hyperphosphatasemia.

We have presented the case of a 7-year-old girl with a two-year history of elevated levels of serum alkaline phosphatase, without evidence of bone or liver disease. Family investigations showed minimal increases in SAP levels in both of her parents. Eight other families with persistent isolated hyperphosphatasemia have been reported previously. This disorder differs from transient isolated hyperphosphatasemia by its later age of detection (usually greater than 5 years), duration of elevation (greater than 1 year), elevation of bone isoenzyme levels alone, and frequent familial incidence.

Alkaline Phosphatase↗
PubMed1987

House staff manuals: a survey of pediatric residency programs.

To determine the role of house staff manuals in residency training, we did a survey of the pediatric residency directors in the United States. Questionnaires were returned from 77% of the programs (179/232). Sixty percent of respondents provided written administrative and medical guidelines to their house staff. Neonatal or pediatric intensive care and emergency protocol information were presented most frequently. Consistent patterns of content and organization were apparent in the 77 manuals reviewed, though style and size varied widely. We conclude that written departmental guidelines are a common and potentially useful educational resource. Evaluation of the effectiveness of manuals to solve patient care or administrative problems is necessary for future refinements in content and format.

Internship and Residency↗
PubMed1987

Ferrite particles for bowel contrast in MR imaging: design issues and feasibility studies.

Diverse materials with varying physical and magnetic properties have been evaluated as gastrointestinal contrast agents for magnetic resonance (MR) imaging. Uniform marking of the small bowel remains the greatest challenge. Ferrites are magnetically active iron oxide particles that are miscible with water and cause loss of signal on MR images. The decrease in MR signal intensity produced by ferrites occurs with a wide range of iron concentrations (0.1-10 mM) and with both T1- and T2-weighted pulse sequences. These effects of ferrites are explained by predominant T2 shortening with negligible T1 effects. The ferrite preparation used in this study was stable in vitro, with little iron solubilized by acid. Intragastric administration of ferrite (5 mg of iron per kg in 6 ml) routinely marked the small bowel of rats. The authors conclude that ferrites represent a promising new class of contrast agents for gastrointestinal MR imaging.

Animals↗
PubMed1986

A single tRNA (guanine)-methyltransferase from Tetrahymena with both mono- and di-methylating activity.

A tRNA (guanine-2) methyltransferase has been purified to homogeneity from the protozoan Tetrahymena pyriformis. The enzyme methylates purified E. coli tRNAs which have a guanine residue at position 26 from the 5' end; it also methylates tRNA prepared from the m22G- yeast mutant trm 1. This methyltransferase is therefore equivalent to the guanine methyltransferase 2mGII found in mammalian extracts. The purified 2mGII from Tetrahymena is capable of forming both N2-methylguanine and N22-dimethylguanine on a single tRNA isoaccepting species; under conditions of limiting tRNA or long reaction times the predominant product is dimethylguanine. Analysis of the products formed under varying reaction conditions suggests that dimethylguanine formation is a two step process requiring dissociation of the enzyme-monomethylated tRNA intermediate.

Animals↗
PubMed1986

Transluminal coronary angioplasty in the elderly.

The safety and clinical efficacy of percutaneous transluminal coronary angioplasty (PTCA) in elderly patients has not been established. Of 639 PTCAs performed between March 1980 and May 1984, 119 patients were 65 years or older (mean 70 years). On angiography, elderly patients differed only in the more frequent occurrence of visible calcific deposits (26% vs 8% in younger patients, p less than 0.01). Primary success was achieved in 81%, vs 80% in patients younger than 65 years. Major complication rates were comparable to those of younger patients: emergency coronary artery bypass surgery, 4.1% vs 4.7%; acute myocardial infarction, 2.5% vs 2.9%; and death, 0.8% vs 0. Late clinical follow-up ranging from 5 to 50 months (mean 18) showed that symptomatic improvement was achieved in 91% of patients in whom PTCA was successful, with 55% being asymptomatic. Seventy percent of patients were as active or more active (30%) than before PTCA and 47% were taking fewer medications. Four late deaths occurred, none from cardiac causes. These data support the safety and clinical effectiveness of PTCA in elderly patients and justify the extension of indications for PTCA to selected patients with multivessel disease in this age group.

Aged↗