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Biomedical subjects

J M Lewis

Publications and source records attributed to J M Lewis.

At least 19 recordsLinked to original sources
PubMed1992

A novel reciprocal chromosome translocation t(11;22)(p13;q12) in an intraabdominal desmoplastic small round-cell tumor.

We report an intraabdominal desmoplastic small round-cell tumor that contains a novel reciprocal chromosome translocation t(11;22)(p13;q12). The tumor showed a reciprocal chromosome translocation which is different from the (11;22)(q24;q12) translocations seen in Ewing's and other small-cell tumors but affects the same break-point on chromosome 22(q12). This reciprocal chromosome translocation may prove to be a marker for intraabdominal desmoplastic small round-cell tumors.

Abdominal Neoplasms↗
PubMed1992

Multifocal epithelioid hemangioendothelioma in bone.

The case of a 17-year-old male with multifocal, grade I epithelioid hemangioendothelioma of the right ankle and foot is presented. The major symptom was poorly localized ankle pain refractory to conservative management. Imaging studies, including roentgenograms, computed tomographic scan, and magnetic resonance imaging, revealed multiple lesions in the right distal tibia, talus, calcaneus, and first cuneiform. An open biopsy of the right talus confirmed the diagnosis, and treatment consisted of localized radiation therapy to the affected area. We review the literature of this rare neoplasm from the initial descriptions to current nomenclatures and conceptualizations of the tumor.

Adolescent↗
PubMed1991

Thirty years of teaching psychotherapy skills.

The author outlines a basic model for teaching psychotherapeutic skills that includes five modules relating to (1) the dynamics of exploration, designed to encourage the patient's affective expression; (2) relationship structure, considering patterns of patient-therapist interaction along a closeness/separateness continuum; (3) affect, empathy, and distance regulation, emphasizing the crucial significance of identifying correctly and responding empathically to patients' affective messages; (4) basic cognitive interventions, focused on techniques for facilitating the patient's narrative flow and capacity to analyze experiences, and for formulating the patient's psychopathology; and (5) the therapist's use of self. The author concludes by examining why systematic psychotherapy training is particularly important at this time, in light of such pressures as managed health care, neuroscientific advances and psychopharmacologic breakthroughs, and the wave of self-help organizations.

Affect↗
PubMed1991

Subcellular distribution of the alpha subunit(s) of Gi: visualization by immunofluorescent and immunogold labeling.

The subcellular distribution of the alpha subunit(s) of Gi has an obvious bearing on the ability of this protein to interact with receptors and targets and on its potential to serve in still unexplored capacities. In this study, we have examined the distribution of Gi alpha by means of light and electron microscopy. The cells employed were mouse 3T3 fibroblasts, normal rat kidney fibroblasts, rat C6 glioma cells, human umbilical vein endothelial cells, and human 293 kidney fibroblasts. By indirect immunofluorescence, two patterns of Gi alpha were evident. The more prominent was that associated with phase-dense, cytoplasmic structures exhibiting a tubule-like morphology. A similar distribution was noted for mitochondria, indicating attachment to a subset of microtubules. The second pattern appeared as a diffuse, particulate fluorescence associated with the plasma membrane. By immunogold labeling and electron microscopy, two populations of Gi alpha were again evident. In this instance, labeling of the plasma membrane was the more prominent. Gold particles were most often evenly distributed along the plasma membrane and were concentrated along microspikes. The second, less abundant population of Gi alpha represented the subunit (or fragments) within lysosomes. Specificity in immunolabeling was confirmed in all instances by immunotransfer blotting, the use of antibodies differing in specificities for epitopes within Gi alpha, the absence of labeling with preimmune sera, and the decrease in labeling after preincubation of antisera with appropriate peptides. These results support the proposal that several populations of Gi alpha exist: those evident within the cytoplasm by immunofluorescence, those present at the plasma membrane, and those evident within lysosomes by immunogold labeling.

Amino Acid Sequence↗
PubMed1990

Percutaneous transluminal coronary angioplasty in octogenarians.

OBJECTIVE: To assess the safety and short- and long-term outcomes of percutaneous transluminal coronary angioplasty in octogenarians. DESIGN: Retrospective chart review of clinical series. SETTING: Referral-based university medical center. PATIENTS: Consecutive series of 54 octogenarian patients (mean age, 82.4 years) who had percutaneous transluminal coronary angioplasty between March 1980 and December 1988. Of these patients, 91% presented with severe angina (Canadian Cardiovascular Society Class III or IV); 59% had unstable angina. Twenty-six patients (48%) had had a previous myocardial infarction and 15 (28%) had had previous coronary artery bypass surgery. Multivessel disease was present in 44 patients (81%). Follow-up ranged from 1 to 50 months (mean, 19 months). INTERVENTION: Percutaneous transluminal coronary angioplasty. MEASUREMENTS AND MAIN RESULTS: The angiographic success rate was 50 of 54 (93%; 95% CI, 81% to 98%) and the clinical success rate was 49 of 54 (91%; CI, 79% to 97%). Two patients had procedure-related myocardial infarction. Two patients died in the hospital, 1 from cardiac tamponade because of pacemaker perforation and 1 from cardiogenic shock after a myocardial infarction despite successful angioplasty. During the follow-up period 4 patients required bypass surgery, 2 had myocardial infarction, and 7 died (4 deaths were cardiac). Eleven patients (20%) had re-stenosis, 7 of whom were managed with repeat angioplasty, including 1 patient who had four procedures. At follow-up, 42 of 45 survivors (93%) were asymptomatic or had class II angina. The Kaplan-Meier survival for all patients, including those who died in the hospital, was 87% at 1 year and 80% at 3 years. Cumulative freedom from major cardiac events (death, myocardial infarction, or coronary bypass surgery) was 81% at 1 year and 78% at 3 years. CONCLUSIONS: Percutaneous transluminal coronary angioplasty can be done in octogenarians with a high rate of angiographic and clinical success, low complication rate, and a favorable long-term (3-year) outcome. As such, it is a treatment option in managing advanced coronary artery disease in this fragile group of patients.

Age Factors↗
PubMed1990

Factors influencing the outcome of balloon aortic valvuloplasty in the elderly.

This study describes the short- and long-term outcome of 44 consecutive percutaneous balloon aortic valvuloplasty procedures performed in 42 elderly patients (age 77.8 +/- 7 years) with calcific aortic stenosis. The initial success rate was 95%, with the peak aortic valve pressure gradient declining from a mean of 82 +/- 32 mm Hg to 44 +/- 23 mm Hg and aortic valve area increasing from a mean of 0.59 +/- 0.15 cm2 to 0.83 +/- 0.40 cm2. One procedure-related death occurred and an additional three patients died less than or equal to 30 days after balloon aortic valvuloplasty. These patients all had New York Heart Association (NYHA) class IV heart failure symptoms prior to the procedure and their mean left ventricular ejection fraction (LVEF) (28 +/- 7%) was lower than that of hospital survivors (52 +/- 13%) (as was their ratio of left ventricular [LV] wall thickness-to-cavity ratio [0.50 +/- 0.10 versus 0.70 +/- 0.15]). At the time of hospital discharge after valvuloplasty, 76% of patients were asymptomatic or markedly improved (NYHA class I or II). After a mean follow-up of 15.5 months (range 2 to 26 months), however, 10 patients had died and 15 had undergone aortic valve replacement for recurrence of NYHA class III or IV symptoms. The adjusted 1- and 2-year survivals were 0.68 and 0.62, respectively, and adjusted 2-year event-free survival was 0.25. Proportional hazard regression analysis indicated that LVEF less than 40% was the only variable affecting survival (p less than 0.01) and was a possible indicator of event-free survival (p = 0.07).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

A functionalized superparamagnetic iron oxide colloid as a receptor directed MR contrast agent.

We have synthesized a surface functionalized superparamagnetic iron oxide colloid whose clearance from the vascular compartment was inhibited by asialofetuin but not fetuin. Unlike other particulate or colloidal magnetic resonance (MR) contrast agents, the agent of the current communication is not withdrawn from the vascular compartment by cells of the macrophage-monocyte phagocytic system, as indicated by its selective increase in hepatic relaxation rates. Because of this we refer to this colloid as a hepatic selective (HS) MR contrast agent. At 20 mumol Fe/kg the HS MR agent darkened MR images of liver. The HS MR agent exhibited no acute toxicity when injected into rats at 1800 mumol Fe/kg. Based on these observations, surface functionalized superparamagnetic iron oxide colloids may be the basis of MR contrast agents internalized by receptor mediated endocytosis generally, and by the asialoglycoprotein receptor in particular.

Animals↗
PubMed1990

TCR gamma/delta+ dendritic epidermal T cells as constituents of skin-associated lymphoid tissue.

The epidermis of all strains of normal mice is populated by two distinct dendritic, bone marrow-derived cells: Langerhans cells and CD4-CD8- Thy-1+ dendritic epidermal T cells (DETC). The overwhelming majority of DETC are an unusually homogeneous population of thymic-dependent cells which express CD3-associated T-cell antigen receptors (TCRs) of the gamma/delta type, thereby distinguishing them from conventional CD4+CD8- or CD4-CD8+ T cells expressing CD3-associated alpha/beta TCR. Most DETC are ontogenetically primitive, derived from early fetal thymocytes with a preferential, but poorly understood tropism for the epidermis. Like the TCR on other populations of gamma/delta cells, which preferentially populate other epithelia such as in the gut and lung, the TCR on most DETC selectively utilize particular variable (V) gene segments (i.e., V gamma 3 and V delta 1 for DETC vs V gamma 5 and V delta 4 or V delta 6 for intestinal intraepithelial lymphocytes). However, unlike other gamma/delta populations whose TCR junctional regions exhibit marked heterogeneity, DETC junctional diversity is extremely limited. This lack of TCR heterogeneity among DETC suggests they recognize a narrow range of physiologic ligands (antigens) and that this recognition is restricted not by conventional polymorphic class-I or class-II MHC molecules, but rather by relatively nonpolymorphic self MHC-like molecules of the class Ib MHC type [e.g., Qa, TL, and CD1 (T6)]. Additional studies are required to clarify precisely what DETC recognize, their relevant biological functions, as well as their relationship(s) to the gamma/delta cells recently identified in human skin.

Animals↗
PubMed1990

First clinical trial of a new superparamagnetic iron oxide for use as an oral gastrointestinal contrast agent in MR imaging.

The authors report the results of preclinical testing and initial clinical application of a superparamagnetic iron oxide specifically prepared as a contrast agent for magnetic resonance (MR) imaging of the gastrointestinal tract. MR imaging was performed at 0.6 and 1.5 T in 15 volunteers. Images of the upper abdomen and pelvis were obtained before and after ingestion of the contrast material at doses of 22.5-225.0 mg of iron in 600-900 L. Two readers scored the images. Delivery of contrast material into the proximal and distal small bowel, with obvious loss of signal intensity (T2 enhancement), was achieved in all subjects. Enhanced images showed improved delineation of the head and tail of the pancreas, anterior margins of the kidneys, and paraaortic region. The contrast agent did not generate artifacts, an improvement over prototype formulations evaluated previously in animals. Except for a brief episode of diarrhea in five subjects, the agent was well tolerated. Use of this contrast agent improved the diagnostic quality of abdominal MR images by enabling the distinction of the bowel from nonbowel structures at concentrations that did not produce image distortion.

Adult↗
PubMed1990

An economic evaluation of the differences between intensive and extensive beef production systems.

A model to evaluate economic criteria involved when cattle are raised on high-forage diets prior to finishing or finished directly after weaning was developed using data from two experiments. In Exp. 1, each year for 3 yr, 136 Charolais-cross calves were weaned and allotted to either an intensive system, in which they were immediately finished on a high-grain diet, or an extensive system, in which they were wintered on crop residues, grazed on summer pasture and finished on a high-grain diet. In Exp. 2, 160 British breed steers were wintered, in one of eight different wintering systems utilizing crop residues, using supplemental protein and(or) alfalfa hay. After wintering, the steers grazed summer pasture and then were finished on a high-grain diet. Overall cost of gain and final "break-even" price were lower for cattle finished through the extensive system except when the price of corn was very low in relationship to other inputs. Interest costs were higher for cattle in the extensive system. Increasing the feeder calf purchase price had almost no effect on differences between the systems. Corn price and purchase price affected both systems similarly, whereas interest rate, wintering yardage and finishing yardage affected each system differently. Because of the additional weight produced through the extensive system, it yielded lower final "break-even" prices in most situations.

Animal Feed↗
PubMed1990

Evaluation of intensive vs extensive systems of beef production and the effect of level of beef cow milk production on postweaning performance.

Charolais-sired calves from three groups of beef cows, similar in growth potential and mature size but different in genetic potential for milk production (5.6, 7.7, 9.0 kg/d; low, medium, and high, respectively), were allotted to two beef production systems each year for 3 yr. At weaning, calves in an intensive (Int) system went directly into the feedlot for finishing (236 d); calves in an extensive (Ext) system were wintered on corn residues (195 d), grazed pasture (115 d) and then were finished (122 d). Postweaning effects of increased weaning weight due to increased level of milk were small and not affected by growing-finishing system. Only the steer calves from the low milk-producing cows showed evidence (P less than .01) of compensatory growth postweaning in response to reduced levels of milk during the suckling phase. Cattle from the Ext system were heavier (P less than .01) before (388 vs 233 kg) and after (595 vs 531 kg) the finishing phase than Int system cattle. During finishing, cattle from the Ext system made more rapid gains (1.70 vs 1.36 kg/d) and consumed more feed (12.4 vs 8.5 kg/d, 2.52 vs 2.19% of average BW) but were less efficient (.137 vs .160, gain/feed) than cattle from the Int system (P less than .05). Extensive systems of beef production produced more total kilograms of beef per animal but they were 196 d older at slaughter.

Animal Husbandry↗
PubMed1990

Effects of rate of gain during winter on subsequent grazing and finishing performance.

Sixty mixed British breed yearling steers (237 kg) were used each year for 2 yr to study the effects of rate of gain during the winter on subsequent pasture and finishing performance. Winter gains of .28, .38 and .50 kg/d (P less than .05) were established for the low, medium and high gain treatments, respectively. Daily gain of steers on pasture was reduced (P less than .01) 81 g for each 100-g increase in winter daily gain. No differences in BW were observed among the treatment groups after grazing summer pasture. Wintering performance did not affect finishing performance. Daily gains during the finishing period increased slightly as pasture gain decreased due to increased feed intake, but efficiency was not altered. These data suggest that within this range of ADG during the winter and under the conditions of this study, it was not beneficial to winter cattle for an ADG more than .28 kg/d.

Animal Feed↗
PubMed1989

Service-mix in general dental practice in Australia.

An understanding of the current service-mix in private general practice in Australia and the factors that may influence its distribution is important in the anticipation of the future practice of dentistry. The present study aimed to describe service-mix, to investigate the association of service-mix with characteristics of presenting patients, and to identify and discuss a number of factors which may be influencing change in service-mix. Service-mix was dominated by restorative, diagnostic and preventive services and a limited number of services accounted for most service provision or dentist time. Both the broad areas of service and more frequently provided services were related to age of presenting patients. Service-mix appears to be changing over time. Changing needs and expectations of patients and philosophies and technologies available to dentists are among factors that push or pull service-mix in new directions. However, changing service-mix and practitioner variation require considerably more exploration.

Adolescent↗
PubMed1978

Distribution of clozapine in the rat: localization in lung.

To determine the distribution of the antipsychotic agent, clozapin (CLZ), a fluorometric procedure for its estimation was devised, and the drug was measured in various tissues of rats after i.p. injection (20 mg/kg). In a 24-hour urine collection, less than 1% injected drug was found. After 1 hour, CLZ concentrations were greatest in lung, spleen, liver and brain (16-64 microgram/g). After 6 hours, CLZ levels in lung remained at 52 microgram/g, whereas concentrations in all other tissues declined to less than 7 microgram/g. When rat lung slices were incubated (O2, 37 degrees C) in CLZ solution (20 microgram/ml), the drug was taken up by the tissue against a concentration gradient, attaining a maximum tissue/medium ratio of 97 after 4 hours. When the concentration of CLZ was raised from 2 to 200 microgram/ml the 1-hour tissue/medium ratio declined from 89 to 21. Chlordiazepoxide, amphetamine and morphine depressed the 1-hour tissue/medium ratio of CLZ by 34 to 50%. CLZ uptake was also decreased 19% by anaerobic conditions and 25% by the presence of 2,4-dinitrophenol. The results suggest that the lung is a site of (active) transport and accumulation for CLZ and perhaps certain other basic drugs.

Animals↗
PubMed1977

Follow-up of adolescents treated in a psychiatric hospital. Predictors of outcome.

In the context of a long-term follow-up of 60 hospitalized adolescent psychiatric patients (26 months to four years after discharge), we examined correlates of outcome. The variables were as follows: (1) severity of psychopathology; (2) onset of symptomatology (process or reactive); (3) type of hospital treatment termination; (4) continuation of individual psychotherapy following discharge; (5) physically destructive behavior before hospitalization; and (6) energy level. Follow-up was by personal clinical interview exploring the expatient's current living conditions, peer relationships, current psychopathology and drug or alcohol use, legal difficulties, academic and work functioning, subjective contentment, and plans for the future. An evaluation was also obtained from parents and/or spouse. Statistical analyses of the interrelationships among the predictor variables and outcome demonstrated the importance of a multivariate approach.

Acting Out↗