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P A McCarthy

Publications and source records attributed to P A McCarthy.

18 recordsLinked to original sources
PubMed1999

Digitized mammograms: a preliminary clinical evaluation and the potential for telemammography.

We performed a preliminary clinical evaluation of digitized mammograms to assess whether digital images suitable for telemammography could be obtained. Thirty mammograms were digitized at a resolution of 4000 x 4000 pixels and 12 bit/pixel. The series contained 17 carcinomas in 16 patients. Five consultant radiologists reported both the original mammograms and the digitized images. There was agreement between the reports of the mammograms and the digitized images in relation to whether a suspicious lesion was present or not in 95% of cases. No study considered benign on viewing the film images was interpreted as malignant on reporting the digitized images. This suggests that film digitizers may allow a digital image of a mammogram of acceptable quality for telemammography to be obtained in the absence of a purpose-built digital mammography system.

Breast Diseases↗
PubMed1999

Comparison of synthetic saponin cholesterol absorption inhibitors in rabbits: evidence for a non-stoichiometric, intestinal mechanism of action.

The hypocholesterolemic activities of pamaqueside and tiqueside, two structurally similar saponins, were evaluated in cholesterol-fed rabbits. The pharmacological profiles of the saponins were virtually identical: both dose-dependently decreased the intestinal absorption of labeled cholesterol 25-75%, increased fecal neutral sterol excretion up to 2.5-fold, and decreased hepatic cholesterol content 10-55%. High doses of pamaqueside (>5 mg/kg) or tiqueside (>125 mg/kg) completely prevented hypercholesterolemia. Decreases in plasma and hepatic cholesterol levels were strongly correlated with increased neutral sterol excretion. Ratios of neutral sterol excreted to pamaqueside administered were greater than 1:1 at all doses, in opposition to the formation of a stoichiometric complex previously suggested for tiqueside and other saponins. Ratios in tiqueside-treated rabbits were less than unity, a reflection of its lower potency. Pamaqueside-treated rabbits exhibited a more rapid decline in plasma cholesterol concentrations than control animals fed a cholesterol-free diet, indicating that the compound also inhibited the absorption of biliary cholesterol. Intravenous administration of pamaqueside had no effect on plasma cholesterol levels despite plasma levels twice those observed in rabbits given pamaqueside orally. These data indicate that pamaqueside and tiqueside induce hypocholesterolemia by blocking lumenal cholesterol absorption via a mechanism that apparently differs from the stoichiometric complexation of cholesterol hypothesized for other saponins.

Administration, Oral↗
PubMed1997

Steroidal glycoside cholesterol absorption inhibitors.

We have explored the use of steroidal glycosides as cholesterol absorption inhibitors which act through an unknown mechanism. The lead for this program was tigogenin cellobioside (1, tiqueside) which is a weak inhibitor (ED50 = 60 mg/kg) as measured in an acute hamster cholesterol absorption assay. Modification of the steroid portion of the molecule led to the discovery of 11-ketotigogenin cellobioside (5, pamaqueside) which has an ED50 of 2 mg/kg. Replacement of the cellobiose with other sugars failed to provide more potent analogs. However, large improvements in potency were realized through modification of the hydroxyl groups on the cellobiose. This strategy ultimately led to the 4", 6"-bis[(2-fluorophenyl)carbamoyl]-beta-D-cellobiosyl derivative of 11-ketotigogenin (51) with an ED50 of 0.025 mg/kg in the hamster assay, as well as the corresponding hecogenin analog 64 (ED50 = 0.07 mg/kg).

Absorption↗
PubMed1997

Mammographic assessment of the symptomatic nonsuspicious breast.

BACKGROUND: Evidence from breast screening programs demonstrates the value of mammography in the detection of asymptomatic breast cancer. METHODS: This study prospectively assessed the role of mammography in the management of 585 patients presenting to a breast clinic, over a 1-year period, with symptomatic breast disease and without clinical or cytological evidence of malignancy. RESULTS: Eighteen (3%) of these patients had breast cancer. Eight patients presenting with nonspecific nodularity had carcinoma. All patients had relatively early disease. CONCLUSIONS: This study suggests that patients with symptomatic disease presenting to a breast clinic represent a group at higher risk of malignancy than screened asymptomatic patients, and that symptomatic women over 40 years of age should have bilateral mammography before being discharged from the breast clinic.

Adult↗
PubMed1995

Colon cancer: morphology detected with barium enema examination versus histopathologic stage.

PURPOSE: To determine the relationship between the morphology of colon carcinomas detected with barium enema examination and the cancer stage. MATERIALS AND METHODS: Clinical, radiographic, endoscopic, surgical, and histopathologic findings were retrospectively reviewed in 152 patients with colon cancer detected with barium enema examination during a 2-year period. RESULTS: Eighty-six patients (57%) had lesions in the rectum and sigmoid and descending colon, and 66 (43%) patients had lesions more proximally in the colon. Lesions on the right side of the colon were less likely to cause symptoms than those on the left side. Eighty-one patients (53%) had annular or semiannular lesions, 57 (38%) had polypoid lesions, and 14 (9%) had plaquelike or carpet lesions. Six patients (4%) had Dukes stage A lesions; 84 (55%), Dukes stage B lesions; 42 (28%), Dukes stage C lesions; and 20 (13%), Dukes stage D lesions. CONCLUSION: Annular or semiannular carcinomas had higher rates of serosal invasion and lymph node metastasis than polypoid carcinomas, but the rates of liver metastases were comparable.

Adenocarcinoma↗
PubMed1993

New approaches to atherosclerosis: an overview.

The mechanisms of action and selected agents for a variety of approaches to the treatment of atherosclerosis have been reviewed. In Table I, each approach is listed according to its primary physiological effect. This is a simplification, of course, and some agents, such as ACAT inhibitors, may have primary effects in all of these categories. As one goes from left to right, the benefit of each physiological effect becomes more speculative. There is no question of the benefit of LDL reduction, but less evidence exists for the clinical benefits of HDL elevation. With regard to direct anti-atherosclerotic effects, most approaches have yet to gather clinical data of any type. Perhaps as a result, the degree of medicinal chemistry effort in each area to date declines as one goes from left to right. This situation is changing rapidly, however. As evidence supporting the HDL hypothesis accumulates and knowledge of how to elevate HDL levels grows, very exciting opportunities for medical advances present themselves. Likewise, the knowledge base for nonlipid intervention is growing and very rapid advances are being achieved with the plaque-imaging techniques needed for evaluating such agents in man. Such results can only lead to greater opportunities for pharmacological intervention. Thus, in the future, much greater research effort will likely be dedicated to HDL elevation and nonlipid approaches. Through these efforts, physicians of the future should be armed with several complementary agents that can reduce the risk of cardiovascular disease in all patient populations.

Anticholesteremic Agents↗
PubMed1990

Efficacy, tissue distribution and biliary excretion of methyl (3R*,5S*)-(E)-3,5-dihydroxy-9,9-diphenyl-6,8-nonadienoate (CP-83101), a hepatoselective inhibitor of HMG-CoA reductase activity in the rat.

Methyl (3R*,5S*)-(E)-3,5-dihydroxy-9,9-diphenyl-6,8-nonadienoate, CP-83101, was identified as a potent competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity, inhibiting enzyme activity in vitro with an IC50 of 8.5 +/- 0.7 microM and a Ki with respect to HMG-CoA of 2.6 microM. CP-83101 also inhibited rat hepatic sterol biosynthesis by 39 +/- 7% at a dose of 100 mg/kg. [3H]CP-83101, administered orally to rats, exhibited peak plasma levels at approximately 1 hr that declined thereafter with an apparent half-time of 2-3 hr. Peak tissue levels also occurred 1 hr following oral administration of [3H]CP-83101. The decline in radioactivity in the liver, however, was considerably slower than that noted in blood, whereas the half-life in non-hepatic tissues was approximately 1 hr. Liver/blood ratios of 14, and liver/lens ratios of greater than 3000, following oral administration of [3H]CP-83101, were similar to those previously reported for other HMG-CoA reductase inhibitors, suggesting a high degree of tissue selectivity. In addition, liver/adrenal and liver/ovary ratios were approximately 1000 at all time points examined between 30 min and 24 hr following oral [3H]CP-83101 administration, indicating a high specificity for hepatic versus other steroidogenic tissues. Evaluation of intravenous versus oral administration of the water-soluble, free acid, sodium salt of [3H]CP-83101 in bile duct canulated rats indicated that approximately 20% of orally administered CP-83101 is absorbed from the gastrointestinal tract, and that absorbed CP-83101 is cleared rapidly from the plasma via the liver and from the liver via the bile. In addition, several lines of evidence suggest that CP-83101 may undergo enterohepatic recirculation. Agents of this synthetic series may thus possess advantages over other HMG-CoA reductase inhibitors with respect to tissue kinetics and specificity.

Administration, Oral↗
PubMed1990

Antiulcer agents. 4-substituted 2-guanidinothiazoles: reversible, competitive, and selective inhibitors of gastric H+,K(+)-ATPase.

A series of 4-substituted 2-guanidinothiazoles has been found to inhibit the gastric proton-pump enzyme H+,K(+)-ATPase. In general, these compounds were reversible inhibitors of canine gastric H+,K(+)-ATPase, competitive at the K+ site, and selective relative to canine renal Na+,K(+)-ATPase. Structure-activity relationship (SAR) studies on this series revealed no general replacement for the guanidinothiazole. On the other hand, use of pyrrolyl, phenyl, and indolyl groups as the C-4 substituent yielded active compounds. Extensive studies of substitution patterns on these 4-aryl groups led to more active compounds, but no consistent SAR became apparent. Monosubstitution of the guanidine and substitution of the thiazole at C-5 both often led to increased activity, but combining these changes generated compounds less active than the parents. Despite 100-fold improvement in in vitro inhibitory potency, only a 3-fold increase in gastric antisecretory activity in rats was observed for these agents.

Adenosine Triphosphatases↗
PubMed1990

Decision making in rehabilitative audiology.

With the emphasis on quality assurance and patient satisfaction in health care, decision making in rehabilitative audiology is a critical issue. Traditionally, rehabilitative decisions have been based on questionable assessment procedures and unproven treatment methods. In this paper, current strategies for decision making with hearing-impaired adults will be presented. Discussion will focus on nonacoustic factors influencing hearing aid fitting, the decision processes necessary for management of the hearing-impaired adult, and expanded uses of self-assessment inventories of hearing handicap.

Aged↗
PubMed1988

Bronchial compression by an enlarged left atrium in infants; a cause of hypovascularity of the left lung.

In three infants seen recently at our institution we noted signs of compression of the left main bronchus associated with enlarged left atria. None of our cases demonstrated the more usual signs of hyperinflation which are a hyperlucent lung field, depressed hemidiaphragm and mediastinal shift away from the affected side. In addition, hypoperfusion of the left lung was noted in each case. We believe that bronchial compression due to an enlarged left atrium, with consequent hypoxic vasoconstriction as a clinically significant entity, which is not well described and may be unappreciated in infants in whom the typical signs of hyperinflation are absent.

Bronchial Diseases↗
PubMed1983

Fetal alcohol syndrome and other alcohol-related birth defects.

This article focuses on the range of fetal anomalies associated with varied alcohol ingestion during pregnancy. A means for identifying women at risk for having infants with alcohol related birth defects and the more severe fetal alcohol syndrome are discussed. Primary methods for preventing these lasting birth defects are described for practitioners.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Work load issues in clinical nursing education.

This survey of 22 baccalaureate (BSN) programs was undertaken to describe and analyze work load issues in BSN nursing education. Academic careers of nursing faculty may be at risk because clinical work load policies generally place less value on clinical teaching than on classroom teaching. Research question addressed teaching credit hours received for each clinical contact hour, remaining weekly hours available for clinical faculty to accomplish service and research activities, and student-to-faculty ratios in clinical settings. Seventy per cent of the programs surveyed allocated less than 1 teaching credit hour to 1 clinical contact hour. Nursing faculty who taught clinical courses with 5:1 to .25:1 work load credit for face-to-face contact hour ratios needed to work between 8 and 24 hours more in face-to-face teaching compared with colleagues teaching lecture courses, thus leaving less time for scholarship and service activities. Fifty per cent of the programs reported 10 or more students in some of the clinical courses. Faculty reported concerns about quality of learning experiences and supervisory difficulties as student numbers in clinical courses exceeded 8 students/faculty member.

Education, Nursing, Baccalaureate↗