Search PubMed⌕ Search

Biomedical subjects

B Collins

Publications and source records attributed to B Collins.

At least 37 records · Page 2Linked to original sources
PubMed1997

Sudden cerebral vasoconstriction during induced polymorphic ventricular tachycardia and fibrillation: further observations of a paradoxic response.

To determine the effect of induced polymorphic VT/VF on the cerebral circulation, transcranial Doppler (TCD) ultrasonography was used to prospectively assess changes in cerebral blood flow velocity during ICD implantation. Fourteen patients (13 men, 1 woman, mean age 58 +/- 20 years, range 34-74 years) who were survivors of an out of hospital cardiac arrest, were evaluated during routine ICD implantation. TCD ultrasonography was used to assess middle cerebral artery systolic velocity (Vs), diastolic velocity (Vd), pulsatility index (PI = Vs-Vd/Vmean) and resistance index (RI = Vs-Vd/Vs) before, during, and after DFT testing with alternating current induction of polymorphic VT/VF. In each of the 14 patients studied, concomitant with the abrupt onset of hypotension, TCD sonography demonstrated a 33% +/- 28% decrease in diastolic velocity, a 42% +/- 28% increase in systolic velocity, a 190% +/- 141% increase in PI, and a 44% +/- 19% increase in RI. These findings reflect an increase in cerebrovascular resistance secondary to arteriolar vasoconstriction distal to the point of insonation of the middle cerebral artery. This response is paradoxic, as the expected response of the cerebral circulation to hypotension is vasodilation, but it is consistent with observations made in other acute hypotensive settings, such as tilt induced neurocardiogenic syncope.

Blood Flow Velocity↗
PubMed1997

Thyroid nodules in the follow-up of irradiated individuals: comparison of thyroid ultrasound with scanning and palpation.

In 1974 we began a prospective study of a cohort of 4296 individuals exposed to therapeutic head and neck irradiation during childhood for benign conditions. To define the role of thyroid ultrasonography in following irradiated individuals, we studied a subgroup of 54 individuals. They all had been screened between 1974-1976 and had normal thyroid scans and no palpable nodules at that time. Thyroid ultrasonography, thyroid scanning, physical examination, and serum thyroglobulin measurements were performed. One or more discrete ultrasound-detected nodules were present in 47 of 54 (87%) subjects. There were a total of 157 nodules, 40 of which were 1.0 cm or larger in largest dimension. These 40 nodules occurred in 28 (52%) of the subjects. Thirty (75%) of these 1.0-cm or larger nodules matched discrete areas of diminished uptake on corresponding thyroid scans. The 10 that did not match (false negative scans for > or = 1.0-cm nodules) were the only nodules of this size in 7 subjects. Of 11 nodules 1.5 cm or larger, only 5 were palpable. Serum thyroglobulin correlated to the number (P = 0.04; r2 = 0.10), but not the volume of the thyroid nodules (P = 0.07; r2 = 0.08). We conclude that thyroid nodules are continuing to occur and are exceedingly common in this irradiated cohort of individuals. The results confirm that thyroid ultrasonography is more sensitive than physical examination and scanning. However, thyroid ultrasound is so sensitive and nodules so prevalent that great caution is needed in interpreting the results.

Child↗
PubMed1997

Home telenursing in Kansas: patients' perceptions of uses and benefits.

Elderly individuals involved in a home telenursing project were studied. The project nurses provided home health services from 'telenursing cockpits' located in three separate sites in Kansas. A cable television-based interactive video system was used to transmit video pictures at 30 frames/s, with 288 horizontal lines of resolution. During phase 1 of the study, interview data were collected from 22 subjects (4 men, 18 women). During phase 2, the original participants were contacted but only 9 (1 man, 8 women) were still receiving home health services. Contrary to expectations, the technology was not an important issue for the participants. They did not express any particular worry or excitement about it. Nor did they describe difficulties in adapting to its use. Use of telemedicine technology did not appear to have any negative effects on communication. The results suggests that further thought needs to be given to defining clearly the purpose and goals of telemedicine projects.

Female↗
PubMed1997

Review of universal health insurance: should we try it?

Health care delivery and finances are fragmented in the United States resulting in inaccessible services to many in need. Other countries with universal health insurance have developed systems that provide basic care for all individuals while maintaining costs in a reasonable range. It is time to make tough decisions to enhance the public's health status and gain control over the destiny of medical practice, while considering the bottom line.

Delivery of Health Care↗
PubMed1997

Structure and activities of agencies providing HIV and AIDS education and prevention to Latina /Latino communities.

Community agencies play an important role in HIV and AIDS education and prevention. On the other hand, important distinctions among these agencies many times go unrecognized by policy makers and program planners. The purpose of this study is to examine differences in the structure and activities of Latina/Latino and non-Latina/Latino agencies that both provide HIV and AIDS education and prevention services to Latina/Latino communities. A total of 280 agencies in counties in four regions of California (the Los Angeles area, the Bay area, the Central Valley, and counties that fell outside these three regions) were surveyed regarding agency characteristics and type and extent of HIV and AIDS education and prevention activities. One hundred eighty-one surveys were returned, a return rate of 65%. Non-Latina/Latino agencies were larger, in terms of staff size, offered a wider range of services, and utilized more volunteer staff than Latina/Latino agencies. Latina/Latino agencies were smaller in size and had more bilingual staff than non-Latina/Latino agencies. Latina/Latino agencies utilized local Spanish-language media more than non-Latina/Latino agencies, and Latina/Latino agencies were more likely to have had their education and prevention activities reported on by local Spanish-language media than non-Latina/Latino agencies. Latina/Latino agencies were more likely than non-Latina/Latino agencies to educate and to show educational videos to one or two persons at a time. Non-Latina/Latino agencies were more likely to do education and prevention activities with migrant farm-workers. There was also an effect of geographic region on types of education and prevention activities.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Advances in pancreas transplantation: the University of Wisconsin experience.

The data show that with careful surgical technique, modern immunosuppression with MMF and FK506, and pancreatic allograft biopsy, it should be possible to achieve: 1) a low rate of technical complications, 2) improved long-term graft survival, particularly in solitary pancreas recipients improving the risk/benefit ratio of this option for nonuremic diabetics, 3) a high safety profile with combined MMF and FK506 immunosuppression, 4) safe transplantation using enteric drainage without increased risk of rejection, infection or graft loss, and 5) successful pancreas transplantation without induction therapy.

Adolescent↗
PubMed1996

A specific RNA structural motif mediates high affinity binding by the HIV-1 nucleocapsid protein (NCp7).

Current research indicates that the nucleocapsid protein (NCp7) of human immunodeficiency virus type 1 (HIV-1) interacts with a variety of RNA substrates during the progression of the viral life cycle. The RNA features specifically recognized by the protein, however, have yet to be identified. SELEX was used to generate a set of RNAs whose affinities for nucleocapsid were on the order of 2 x 10(-9) M. Comparative analysis revealed that each RNA contains a highly conserved fourteen nucleotide sequence-block. Computer modeling and structure probing experiments indicate that the RNA ligands use the consensus sequence to fold into hairpins with an identical asymmetric bulge. The presence of the nucleocapsid protein protects the asymmetric bulge from ribonuclease attack, suggesting that it is the key element in protein recognition. A search for similar structural motifs within the HIV genome reveals several potential interaction sites for the nucleocapsid protein.

Base Sequence↗
PubMed1996

Same day surgery: results of a patient satisfaction survey.

Same day surgery patients have unique needs, distinct from those of traditional long-stay inpatients and outpatients. Their postoperative needs at home are central to achieving complete recovery and ensuring there are no unplanned readmissions to hospital. In a quality improvement project at Royal Perth Hospital, a patient satisfaction questionnaire survey has attempted to measure the clinical outcome of same day surgery patients and whether this is influenced by factors such as the specific information expectations and needs of these patients, including their postoperative information needs and expectations. Survey results highlight that information delivery is crucial to same day surgery patients, not only in preparing for their procedure, but also in planning for, and coping with, their postoperative course. Information delivery is a principal factor influencing both clinical outcome and patient satisfaction with hospital service. Improving information delivery can contribute greatly to the quality and effectiveness of same day surgery services and ensure the continuum of care.

Adult↗
PubMed1995

Aneuploidies and micronuclei in the germ cells of male mice of advanced age.

The objective of this research was to determine whether the frequencies of chromosomally defective germ cells increased with age in male laboratory mice. Two types of chromosomal abnormalities were characterized: (1) testicular spermatid aneuploidy (TSA) as measured by a new method of multi-color fluorescence in situ hybridization (FISH) with DNA probes specific for mouse chromosomes X, Y and 8, and (2) spermatid micronucleus (SMN) analyses using anti-kinetochore antibodies. B6C3F1 mice (aged 22.5 to 30.5 months, heavier than controls but otherwise in good health) showed significant approximately 2.0 fold increases in the aneuploidy phenotypes X-X-8, Y-Y-8, 8-8-X and 8-8-Y with the greatest effects appearing in animals aged greater than 28 months. No age effect was observed, however, in X-Y-8 hyperhaploidy. Major age-related increases were seen in Y-Y-8 and X-X-8 hyperhaploidies suggesting that advanced paternal age is associated primarily with meiosis II rather than meiosis I disjunction errors. A approximately 5 fold increase was also found in the frequency of micronucleated spermatids in aged mice when compared with young controls. All micronuclei detected in the aged animals lacked kinetochore labeling, suggesting that they either did not contain intact chromosomes or the chromosomes lacked detectable kinetochores. The findings of the TSA and SMN assays are consistent with meiotic or premeiotic effects of advanced age on germ cell chromosomes, but there were differences in the age dependencies of aneuploidy and micronuclei. In summary, advanced paternal age may be a risk factor for chromosomal abnormalities (both aneuploidy and structural abnormalities) in male germ cells.

Aging↗
PubMed1995

Changes in cerebral blood flow velocity associated with biofeedback-assisted relaxation treatment of migraine headaches are specific for the middle cerebral artery.

Twenty-five patients with diagnosed migraine headaches were randomly assigned to a biofeedback-assisted relaxation therapy group or to a group who relaxed on their own. This study confirmed that the biofeedback trained group significantly decreased pain and medication more than the self-relax group. The best responders were those with the more elevated initial cerebral blood flow values and the changes in cerebral blood flow were specific for the middle cerebral artery.

Adult↗
PubMed1995

EPR persistence measurements of UV-induced melanin free radicals in whole skin.

Electron paramagnetic resonance is used to detect the formation of free radicals caused by exposure to ultraviolet radiation in chemically untreated rabbit skin. A fast jump in EPR signal level, occurring over a few seconds, is observed immediately after a skin sample is exposed to UV. This is followed by a slower increase toward an elevated steady-state signal over a period of hours as the skin is continuously exposed to a UV light source. Upon cessation of UV light exposure, EPR signal levels undergo an abrupt drop followed by a slower decay toward natural levels. Elevated free radical concentrations following UV exposure are found to persist for several hours in whole skin. These results are consistent with time-resolved EPR measurements of photoinduced radicals in various natural melanins.

Animals↗
PubMed1994

An analysis of avian reproduction studies submitted for pesticide registration.

Avian reproduction studies are currently part of the regulatory ecotoxicology requirements for pesticides in many countries. In the study, 134 avian reproduction studies were reviewed to determine their ability to identify pesticides that have the potential to affect reproduction in wild birds. A clustering procedure was first used to assign measured variables to parental, developmental, or eggshell effects. This assignation was found to be identical in the two bird species tested. Nineteen of 69 pesticides tested were found to cause developmental effects at levels lower than those giving rise to detectable parental toxicity. At least some of these should not have been registered without some assurance that developmental effects would not occur in the wild. The analysis also found very little similarity in the effects of pesticides on the two bird species commonly used in avian reproduction tests. This casts serious doubts on the ability to extend the results of avian reproduction studies to any potentially affected bird species. Modifications to the avian reproduction test, based on results of the analysis conducted, are suggested. It is recommended that the avian reproduction study be recognized as a rough screening tool only and that efforts not be made to make it more realistic, e.g., such as through a reduced exposure period.

Animals↗
PubMed1994

Cells surrounding haemodialysis-associated amyloid deposits are mainly macrophages.

Dialysis-related amyloidosis is a type of amyloidosis which had beta 2-microglobulin as the major protein constituent and occurs predominantly in haemodialysis patients. Its prevalence is very high with increasing time on dialysis treatment and its pathogenesis is not completely understood. While remarkable progress has been made in the identification of the components of the deposits, there are no reports characterizing the cells surrounding the amyloid fibrils. To characterize the cellular composition of the amyloid material, specimens from seven patients treated by maintenance haemodialysis were studied with immunoperoxidase labelling using monoclonal antibodies to leukocytes (CD3, CD14, CD68, CD4, CD8, CD45). The results were very reproducible for the seven deposits assessed: Of the 182 +/- 26 leukocytes/0.2 mm2 of amyloid tissue expressing the 71.5-CD45 marker (common leukocyte), 91 +/- 6% were CD68 (KP1) positive (monocyte macrophage). No CD3-positive cells (T-cell marker) were found in six of the seven patients, with only 1.6% in the remaining one. The present study shows that although amyloidosis has classically been considered as an acellular pathology, clearly there are cells surrounding amyloid fibrils. Strikingly, these cells are almost exclusively macrophages; there are no lymphocytes or granulocytes. The putative role of macrophages in the pathogenesis of beta 2-microglobulin amyloidosis remains to be established. However, the identification and quantitation of the cells surrounding the amyloid deposits may be important for subsequent studies to elucidate amyloid pathogenesis and particularly protein-cell interactions.

Adult↗