PubMed Health⌕ Search

Biomedical subjects

R W Holden

Publications and source records attributed to R W Holden.

At least 19 recordsLinked to original sources
PubMed1995

A survey of drinking behaviors of Canadian correctional officers.

77 correctional officers from two Canadian medium security penitentiaries were surveyed concerning their use of alcohol. 94% reported drinking at least once during the preceding year. 45 men consumed alcohol more frequently than the 29 women, more often felt obligated to drink at social gatherings, and were more likely to believe that drinkers do not suffer health problems related to their drinking. Although other studies have indicated correctional officers have special problems with drinking, more similarities with the general population than differences were found in the present drinking patterns.

Adult↗
PubMed1995

Past and current drug use among Canadian correctional officers.

Current and past drug use was assessed in a sample of 77 Canadian correctional officers working in two medium-security penitentiaries. 58% of correctional officers indicated past illicit drug use. This compares with 20% of Canadians who indicate illicit drug use. Correctional officers were more likely than the general population to have used marijuana and cocaine.

Adolescent↗
PubMed1991

Pathways to improved radiologic research. An NIH workshop.

In summary, the workshop recommended two years of research training as being essential for radiologists to acquire the skills and knowledge necessary to begin a successful research career in today's funding and academic environment. Many pathways can combine two years of research training and provide fulfillment of existing requirements to achieve specialty certification and subspecialty credentialing. Departments of radiology supporting the beginning qualified investigator should allow him or her approximately 75% research time for the first three years of the academic appointment. Departmental research time accorded faculty members may best be concentrated on a few individuals, providing them sufficient time to be competitive for peer-reviewed grants and enabling research advances to provide a solid foundation for the future of radiologic imaging.

Humans↗
PubMed1990

Plasminogen activators: pharmacology and therapy.

Biochemical advances are providing new insights into coagulation and fibrinolysis. Integrating this biochemical knowledge into plasminogen activator therapy improves understanding of currently available enzymes. Basic components of the fibrinolytic system are discussed and the chemical structures, pharmacokinetics, dosages, and modes of delivery of current and future plasminogen activators are reviewed.

Antifibrinolytic Agents↗
PubMed1989

Limb salvage in high-risk patients with multisegmental disease.

Is percutaneous iliac angioplasty before distal bypass a logical limb salvage option in a high-risk patient? A retrospective review of 113 iliac angioplasty procedures identified 10 patients in this situation. Angioplasty preceded femoropopliteal bypass (five), femorotibial bypass (three) and, in one case each, femorofemoral bypass or profundoplasty. There were no interventional deaths or complications. Ankle/brachial pressure index improvement followed intervention: 0.28 + 0.2 vs. 0.92 + 0.08, (p less than 0.0005). Limb salvage was 90% at one month, 80% at six months and 70% at one to three years by Life-Table analysis. Two patients with a patent bypass lost limbs from uncontrolled infection within two months. One patient required an amputation 311 days after the only failure of angioplasty and distal bypass. During this study period, 56% of the patients died. This review supports an angioplasty/bypass combined intervention as a valuable treatment option in high-risk patients facing limb loss.

Aged↗
PubMed1988

Economics of breast examination in the United States.

Screening mammography is expensive and will increasingly be challenged by professional health care economists. The cost of breast biopsies generated from screening mammography is also very significant. The breast imaging and surgical communities must accept this economic challenge and work to improve cost-effective breast health care delivery systems.

Biopsy↗
PubMed1988

Variation of transducer frequency output and receiver band-pass characteristics for improved detection and image characterization of solid breast masses.

A new approach has been used for ultrasound detection of small benign and malignant breast masses, namely, control of scattering in such a manner that a small mass can be easily recognized because of the effect of the scattering on the contrast between the mass and the surrounding normal tissue. Maintenance of good resolution as scattering is varied is an essential aspect of this approach. Image contrast is dependent on a number of instrumentation parameters but, in a fundamental sense, it is related to differences in the amount of scattering between a solid breast mass and the surrounding normal tissue. In the subject studies, modification of image contrast is accomplished by varying either the center frequency output of the transducer or the band-pass of the receiver. These approaches take advantage of differences in the frequency dependence of scattering coefficients of solid breast masses and normal tissue. A unique technique for varying center frequency without switching transducers was developed, namely, use of a wide bandwidth, co-polymer PVDF transducer, in combination with certain instrumentation conditions which allow the center frequency output of a single ultrasound transducer to vary over a relatively wide frequency range. Using this technique, an automatic B-mode ultrasound imaging breast instrument which allows emission of 3.5, 4.5, 6.5 and 11 MHz ultrasound frequencies from the same co-polymer transducer was used to examine patients with solid breast masses. Both a wide band-pass receiver, similar to that commonly used in clinical ultrasound systems and a tunable receiver (which allows variation of the band-pass from wide to narrow) was used with this automated system. Using the standard receiver system, it was found that there are advantages to having a range of transducer frequencies immediately available for breast examination. These include: (1) improved detection of masses located in highly attenuating regions of breast (by decreasing frequency); (2) availability of diagnostically relevant information at some one frequency which may not be apparent at other frequencies. Using the multiple frequency system and the standard receiver, it was found that the most appropriate examination frequencies for detection and diagnosis of fibroadenomas are higher frequencies (8 to 11 MHz). This is particularly true in the case of fibroadenomas in fatty breasts.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenofibroma↗
PubMed1987

Detection of acute gastrointestinal bleeding by intra-arterial Tc-99m sulfur colloid scintigraphy in a canine model. Preliminary study.

The diagnostic sensitivities of arteriography, intravenous (IV) Tc-99m sulfur colloid scintigraphy, and intra-arterial (IA) Tc-99m sulfur colloid scintigraphy were evaluated in a canine model of gastrointestinal bleeding. Fifteen dogs were studied at bleeding rates ranging from .4 to 1.0 ml/minute. All three studies were obtained in six of the 15 dogs. Intravenous scintigraphy was superior to angiography in two cases, inferior in three, and equal in one. No significant difference could be shown between these two tests at these bleeding rates. Intra-arterial scintigraphy was superior to angiography in four cases and equal in two (P = .06). It was superior to IV scintigraphy in five cases and inferior in one (P = .10). In this small preliminary study, IA scintigraphy appears to be superior to the other two modalities and may prove useful in the detection of acute bleeding at the time of negative arteriography, and in serial studies in patients receiving Pitressin.

Acute Disease↗
PubMed1987

Interventional radiology for restoration of vascular patency in the postoperative patient--case reports.

The postoperative patient may present with one or more of a variety of problems amenable to management by interventional radiologic techniques, which may be curative by themselves or may, in addition, require or allow successful surgical intervention. To optimize patient care, a good working relationship between the vascular surgeon and the interventional radiologist is essential. Consideration should be given to the patient's presenting signs and symptoms, the surgical history with its alteration of anatomy, the results of available noninvasive studies, and knowledge of various therapeutic alternatives. Vascular radiologic interventions include angioplasty, thrombolytic therapy, a combination of both angioplasty and thrombolysis, and newer techniques such as percutaneous valvectomy. In this report, examples of some of the experience at Indiana University are presented. Emphasis is placed on the appropriate approach to the patient.

Adult↗
PubMed1986

Indeterminate lung imaging. Can the number be reduced?

During a 2 1/2-year period, 1131 patients with suspected pulmonary embolism had ventilation-perfusion lung scans; 150 of these patients also underwent pulmonary angiography. In a retrospective study, these 150 patients were re-evaluated using the reference criteria of Biello and Alderson, with 62% read as indeterminate. Twenty patients who had chronic obstructive pulmonary disease with retention of Xe-133 in greater than 50% of the lung fields without corresponding radiographic abnormality were included. Ventilation/perfusion matches and mismatches could be correctly determined in 15 of these patients. These 15 of 20 studies could be correctly reclassified as low-probability, while the other five remained indeterminate. With increasing intervals between ventilation/perfusion lung imaging and the onset of symptoms, the percentage of patients with proven pulmonary emboli correctly diagnosed as high probability continuously decreased, and the percentage of studies read as indeterminate constantly increased. Serial chest radiographs suggested that the development of infiltrates in the region of the embolus convert high-probability ventilation/perfusion scans to indeterminate.

Humans↗
PubMed1986

The spectrum of sonographic findings of fibroadenoma of the breast.

There are a number of sonographic findings seen in fibroadenoma of the breast. In a retrospective study, we examined the biopsy results of 59 masses given the sonographic diagnosis of fibroadenoma. We also reviewed the sonograms of an additional 26 biopsy-proven fibroadenomas that were not diagnosed as such with ultrasound. The ultrasound diagnosis was correct in 50 of 76 fibroadenomas (65.8%). Only 12 of the 76 biopsy-proven fibroadenomas had the classic sonographic appearance of a smooth round or oval mass with homogeneous internal echoes. Fourteen fibroadenomas were not visible on the sonograms, even in retrospect. The remaining 50 biopsy-proven fibroadenomas demonstrated one or more "atypical" signs of border irregularity, lobulation, inhomogeneous internal echo texture, or posterior shadowing. There were nine sonographic false positives: five patients had other benign lesions on histology, and four masses believed to be sonographically compatible with fibroadenoma were found to be carcinomas. While breast sonography is frequently a useful modality for breast mass detection, particularly as an adjunct to x-ray mammography, the common overlap in characteristics of benign and malignant masses makes histologic evaluation of all solid masses essential.

Adenofibroma↗
PubMed1986

Intracoronary administration of streptokinase in a canine model. Disturbance in thromboxane A2-prostacyclin balance.

The potential impact of local intracoronary infusion of streptokinase (SK) on vascular prostaglandin synthetic pathways was studied in a canine model. Control animals (n = 10) underwent left coronary artery (LCA) infusion of 50,000 units SK for 90 minutes; experimental animals (n = 10) underwent LCA infusion of normal saline. Plasma samples for radioimmunoassay (RIA) of prostacyclin (PGI-2) and thromboxane (TXA-2) were obtained from the coronary sinus (CS) as follows: one sample preinfusion, six samples during infusion, and three samples postinfusion in each animal. Comparisons between control and experimental plasma levels of PGI-2 and TXA-2 were made for each sampling time. The PGI-2 levels remained at or below the lower limits of detectability by RIA (the most sensitive assay available) in both control and experimental animals. TXA-2 levels were higher in experimental than in control animals at all sampling times, with the most significant differences occurring in samples 3 (after 30 minutes of infusion, .001 less than P less than .01), 4 (after 45 minutes of infusion, .05 less than P less than .10), and 5 (after 60 minutes of infusion, .02 less than P less than .05). We suggest (1) it is unlikely that any of the beneficial effects of coronary streptokinase infusions are PGI-2-mediated, (2) that the TXA-2 increases in our model may represent a pathophysiologic-biochemical correlate of previously identified morphologic evidence of endothelial damage in animals infused with fibrinolytic agents, and (3) that our findings may indicate that fibrinolytic infusions produce competing effects: lysis of thrombi and endothelial injury with TXA-2 production.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Automated breast sonography using a 7.5-MHz PVDF transducer: preliminary clinical evaluation. Work in progress.

Breast ultrasound imaging performed with an automated machine was carried out in 89 patients, and images obtained with a conventional ceramic single-focus 4-MHz transducer and a 7.5-MHz polyvinylidene fluoride (PVDF) transducer were compared. The 7.5-MHz PVDF transducer improved overall image quality in 77% of patients and had equal penetration in 83%. It yielded greatly increased diagnostic information in 43% of 81 masses and improved visualization of calcification in 57% of 14 lesions in which calcium was visible on mammograms.

Adolescent↗
PubMed1986

Cerebrovascular disease: evaluation with transbrachial intraarterial digital subtraction angiography using a 4-F catheter.

Three hundred sixty-one patients underwent intraarterial digital subtraction angiography for definite or probable occlusive vascular disease of the carotid arteries. Examinations were performed with 65-cm-long, 4-F aortic catheters. A transbrachial approach was used. Images were good or excellent in nearly all cases. No postprocedural neurologic deficits or hematomas occurred. Permanent pulse deficit occurred in two patients, and temporary deficit occurred in three patients, an improvement over the frequency found in previous transbrachial series using 6-8-F catheters. While these results establish the efficacy of this technique, they also indicate a possible greater relative safety in men than in women.

Angiography↗