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Biomedical subjects

C Ryan

Publications and source records attributed to C Ryan.

At least 109 records · Page 6Linked to original sources
PubMed1990

Fluorescence studies with potato carboxypeptidase inhibitor.

Potato carboxypeptidase inhibitor (CPI) is a 39-residue globular protein whose X-ray structure is known. The protein's two tryptophan residues (W22 and W28) appear to be on the surface in the crystal structure. The fluorescence spectrum of CPI has a maximum at 344 nm. Acrylamide solute quenching yields an upward curving Stern-Volmer plot with KSV approximately 9 M-1. KI quenching yields a linear plot with KSV approximately 5.5 M-1. These studies indicate that emission occurs from a solvent exposed residue(s). Fluorescence lifetime measurements were fitted to a biexponential decay law with tau 1 = 0.9 ns. f1 = 0.22 and tau 2 = 3.9 ns. Anisotropy decay data were described by a single rotational correlation time of 1.2 ns. This value is somewhat small for the global rotation of a protein of this size. The low temperature phosphorescence of CPI shows a biexponential decay, with a rapidly decaying 0.5-1.0 second component. The triplet state of at least one of the two tryptophan residues must be perturbed by interaction with nearby disulfide bonds.

Acrylamides↗
PubMed1990

Usefulness of tomographic thallium-201 imaging for detection of restenosis after percutaneous transluminal coronary angioplasty.

The role of tomographic thallium-201 exercise and redistribution imaging in the detection of restenosis after percutaneous transluminal coronary angioplasty (PTCA) was evaluated in 116 patients: 61 (53%) with 1- and 55 (47%) with multivessel PTCA, with a total of 185 dilated vessels. Complete revascularization was performed in 89 (77%) and partial revascularization in 27 (23%) of the patients. Restenosis was angiographically demonstrated in 69 (60%) of the patients and 85 (46%) of the vessels 6.4 +/- 3.1 months after PTCA. Disease progression in previously normal vessels was noted in 11 patients. The results were: (1) for detection of restenosis in the group of patients, single-photon emission computed tomographic (SPECT) versus exercise electrocardiographic sensitivity was 93 vs 52% (p less than 0.001), specificity 77 vs 64%, and accuracy 86 vs 57% (p less than 0.001). The results were similar in the complete and partial revascularization groups. (2) SPECT was 86% sensitive, specific and accurate for restenosis detection in specific vessels with comparable results for 1-versus multivessel PTCA and complete versus partial revascularization. Sensitivity, specificity and accuracy were: 89, 95 and 92% for the left anterior descending coronary artery; 88, 79 and 82% for the right coronary artery; and 76, 83 and 85% for the left circumflex coronary artery. Eighty-one percent of the diseased nondilated vessels were correctly identified. (3) Disease progression to greater than 50% stenosis was detected with 91% sensitivity, 84% specificity and 85% accuracy. SPECT thallium-201 imaging is an excellent tool for the detection of restenosis and disease progression after PTCA in the settings of 1- and multivessel angioplasty and complete and partial revascularization.

Angioplasty, Balloon, Coronary↗
PubMed1990

Health effects of long-term solvent exposure among women in blue-collar occupations.

The relationship of solvent exposure to self-reported neurologic and somatic symptoms as well as neuropsychological performance was examined in a sample of 567 female blue collar workers who were members of the International Brotherhood of Electrical Workers (IBEW). Structured interviews were conducted at IBEW offices. Five solvent exposure categories were derived--never exposed, exposed prior to but not during the past year, exposed during the past year but not currently, currently exposed less than 50% of the time, and currently exposed more than 50% of the time. No differences among the groups on neuropsychological performance were found. On the other hand, heightened exposure was significantly related to depression, severe headaches, light-headedness, room spinning, appetite difficulties, funny taste in mouth, weakness/fatigue, rashes, and abdominal pain after controlling for the effects of seven risk factors (age, smoking, moderate-heavy alcohol consumption, severe obesity, history of physician-diagnosed chronic illness, working in a clean room, and exposure to other chemicals). These findings are consistent with Scandinavian studies of solvent-exposed male workers and point to the need for careful prospective research.

Adult↗
PubMed1990

Cardiac surgery in patients over the age of 80 years.

The risk-benefit relationship of open heart surgery in octogenarians is not well established. Eighty consecutive patients over the age of 80 who underwent cardiac operations under cardiopulmonary bypass were evaluated. Twenty-five patients were in functional class IV, 42 in class III, and 13 in class II. Forty-four patients had only coronary artery bypass grafts (CABG), 12 only aortic valve replacement (AVR), 6 only mitral valve replacement (MVR), 12 CABG and AVR, 4 CABG and MVR, 1 CABG and aneurysmectomy, and 1 had resection of left atrial myxoma. Operative mortality (within 30 days) was 12.5% for the group. Mortality was related to bleeding, left ventricular failure, primary ventricular fibrillation, pulmonary failure, and renal failure. Mortality was higher in patients with (1) advanced functional class, (2) mitral valve replacement, (3) postoperative hemorrhage, and (4) associated pulmonary disease. While a generally conservative approach is recommended for octogenarian patients, many with life-threatening cardiac disease, especially those free of major multisystem illnesses, should not be denied the benefit of surgical treatment.

Aged↗
PubMed1990

Performance characteristics of a novel immunoassay based on hybrid Ty virus-like particles (Ty-VLPs): rapid differentiation between HIV-1 and HIV-2 infection.

Recombinant antigens containing all or parts of the HIV-1 proteins p24, Nef and gp41 and HIV-2 gp36 have been purified and used to develop a rapid immunoassay to detect and differentiate between HIV-1 and HIV-2 antibodies in a single test. The antigens were produced as particulate fusion proteins by exploiting the ability of a protein encoded by the yeast retrotransposon Ty to assemble into virus-like particles (Ty-VLPs). Hybrid HIV: Ty-VLPs carrying each of the antigens were applied to nitrocellulose strips at specified locations in a slot-blot format and then used to detect antibodies present in human serum and plasma samples of diverse geographical origin. Previously confirmed HIV-1- and HIV-2-positive samples were readily and reliably identified. The assay was used to identify a case of HIV-2 infection in an African woman who had been resident in the Oxford region for the last 3 years and to analyse the prevalence of anti-HIV antibodies in a longitudinal study of seroconverting patients. We also demonstrate that the assay works efficiently with whole blood.

Adult↗
PubMed1990

Psychiatric sequelae after traumatic injury: the Pittsburgh Regatta accident.

Accidental injury in a child is sudden, often violent, and emotionally stressful, particularly when it is accompanied by hospitalization and rehabilitation. The following case report examines the presence of post-traumatic stress disorder and other psychiatric illnesses in five children involved in a boating accident during the 1988 Pittsburgh Regatta and considered severity of injury as well as complicating psychosocial stressors in the development of the disorders. The presence of symptoms was not related to the nature or extent of the injury but was instead the by-product of additional factors, including level of family stress, coping styles of the patient and family, positive psychiatric history in the child and/or family, and experience in effectively dealing with stressful episodes in the past.

Accidents↗
PubMed1990

Unstable angina and coronary angioplasty.

Of 2,122 consecutive patients undergoing elective coronary angioplasty from 1982 to 1985, 62% had stable angina pectoris (SAP), and 38% had unstable angina pectoris (UAP). There were differences between the two groups in clinical and morphological factors and in initial and late results of angioplasty. UAP patients were more likely than SAP patients to be smokers and to have had prior myocardial infarctions. Lesions in UAP patients were more severe, longer, more eccentric, more irregular, and more likely to have intracoronary thrombi than were lesions in SAP patients. Coronary angioplasty success was achieved in 84% of UAP and in 88% of SAP patients (p less than 0.05), and complications occurred in 6.7% of UAP and in 4.7% of SAP patients (p less than 0.05). Hospital death rates were low and similar, 0.2% for both groups. Follow-up (mean, 37 months) showed recurrent Canadian Cardiovascular Society (CCVS) class III/IV angina in 30.1% of UAP and in 25.2% of SAP patients (p less than 0.05). There was a return to work in 86% of UAP and in 91% of SAP patients (p less than 0.05). When UAP patients' durations of symptoms were further fractionated, it was found that the earlier angioplasty was performed after onset of angina, the lower was the success rate and the higher the complication rate and incidence of late follow-up untoward events. When coronary angioplasty was performed within 1 week of onset of angina ("early"), success was 79.1%; when angioplasty was performed 2 weeks or more after onset of angina ("later"), success was 86.3%. Major cardiac events occurred in 11.5% in the early group and in 4.8% in the later group (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1990

Calcium-channel blockers and the elderly.

Calcium-channel blockers may well be the drugs of choice for treating angina, hypertension, and supraventricular arrhythmia in the elderly. They are effective, have no serious side effects, and when wisely matched to the patient, are very well tolerated. Most calcium-channel blockers can be administered once or twice daily. A choice of four is available; only verapamil and diltiazem hydrochloride are useful for supraventricular arrhythmia. All four, however, are effective for the treatment of hypertension and angina. Expanding uses of calcium-channel blockers include peripheral vascular disease and migraine. There may be a theoretical advantage in humans from the point of view of the anti-atherosclerosis demonstrated in animals.

Angina Pectoris↗
PubMed1989

Autosomal dominant retinitis pigmentosa (ADRP): localization of an ADRP gene to the long arm of chromosome 3.

Members of a large pedigree of Irish origin presenting with early onset Type I autosomal dominant retinitis pigmentosa (ADRP) have been typed for D3S47 (C17), a polymorphic marker from the long arm of chromosome 3. Significant, tight linkage of ADRP to D3S47, with a lod score of 14.7 maximizing at 0.00 recombination, has been obtained, hence localizing the ADRP gene (RP1) segregating in this pedigree to 3q.

Chromosome Mapping↗
PubMed1989

Expression of proteinase inhibitors I and II in transgenic tobacco plants: effects on natural defense against Manduca sexta larvae.

Genes containing the cauliflower mosaic virus 35S promoter fused to open reading frames coding for tomato proteinase inhibitor I, tomato inhibitor II, and potato inhibitor II were expressed in transgenic tobacco plants. Inhibitor I and II proteins were identified by immunoblotting and quantified by immunoradial diffusion. Both inhibitors exhibited the molecular weights found for the native proteins in their natural environments. Extracts of leaves from transformed plants contained inhibitory activities against trypsin and chymotrypsin that reflected the levels of inhibitor I or II protein present. The results demonstrate that in tobacco leaves the introns of both inhibitor I and inhibitor II genes were excised correctly and that pre and prepro inhibitor I and II proteins were correctly processed. Growth of Manduca sexta larvae (tobacco hornworms) feeding on leaves of transgenic plants containing inhibitor II, a powerful inhibitor of both trypsin and chymotrypsin, was significantly retarded, compared to growth of larvae fed untransformed leaves. Levels of inhibitor II protein as low as 50 micrograms/g of tissue moderately affected larval growth, whereas levels above 100 micrograms/g severely reduced growth. The presence of tomato inhibitor I protein, a potent inhibitor of chymotrypsin but a weak inhibitor of trypsin, in transgenic tobacco leaves had little effect on the growth of the larvae. These experiments indicated that trypsin inhibitory activity, but not chymotrypsin inhibitory activity, was mainly responsible for the inhibition of larval growth.

Animals↗
PubMed1989

Atrioventricular block in accidental hypothermia--a case report.

The finding of second-degree and high-grade atrioventricular block in a patient with severe accidental hypothermia is described. Additional findings included atrial fibrillation, severe sinus bradycardia, and prominent J (Osborn) waves. This case represents, to the authors' knowledge, the first report of advanced spontaneous AV block not induced by atrial pacing in severe accidental hypothermia. Reversal of the block, and other characteristic changes, suggest a relationship to low temperature.

Aged↗
PubMed1989

Encephalopathy and vestibulopathy following short-term hydrocarbon exposure.

Dizziness, headaches, and weakness occurred among three men after short-term hydrocarbon exposure during improper welding procedures in a closed container. Symptoms were related to objective evidence of vestibular and cognitive dysfunction. Symptoms and abnormal test results persisted for 6 to 18 months. Simulation of the accident failed to demonstrate likely exposures except aliphatic hydrocarbons, well within the permissible exposure levels. Short-term exposures to neurotoxins may lead to long-term central nervous system abnormalities.

Accidents↗
PubMed1988

Transluminal coronary angioplasty in the treatment of silent ischemia.

Fifty-four asymptomatic patients with positive thallium exercise tests underwent coronary angiography followed by coronary angioplasty (PTCA), as the primary therapy for silent ischemia. The procedure was technically successful in 89% of these patients. Emergency bypass graft surgery was necessary in 2 (3.6%) and q-wave myocardial infarction occurred in 1 (1.8%) of these. All fifty-four patients have been followed for a mean of 35 months since angioplasty. Of the 48 patients with initially successful PTCA, 12 had either clinical restenosis (9/14 or 19%) or a new lesion (3/48 or 6%) during follow-up, which required a repeat PTCA. At the longest follow-up, 46 (85%) had been successfully treated with on or more PTCA procedures. Two patients (3.6%) had sustained late q-wave myocardial infarction and two additional patients reported angina pectoris. There were no deaths. Angioplasty as a primary therapy for silent ischemia appears efficacious, with success and restenosis rates comparable to those in the symptomatic population. Event-free survival is improved, compared with natural history data for patients with silent ischemia from other studies. Prudent risk/benefit analysis may help to define subgroups most likely to benefit from this intervention.

Adult↗
PubMed1988

Sinus node suppression in acute strokes--case reports.

The authors report on 5 patients, 4 of them observed over a period of only two months in one community hospital, who developed profound sinus node suppression in the early phase following acute strokes. This complication resulted in the death of 2; in the remaining 3, it was controlled by electrical cardiac pacing or intravenous atropine. In 3 patients, the strokes were due to subarachnoid hemorrhage, and in 2, they were secondary to vascular occlusion. In at least 4 patients, the prognosis seemed favorable from a neurologic standpoint. Vagally mediated sinus node arrest may, therefore, represent a potentially fatal complication of strokes and may be more frequent than currently appreciated. Continuous monitoring in the early phase of acute strokes and pacemaker therapy may be lifesaving in some patients. This and the general phenomenon of functional failure of the sinus node due to a variety of causes are discussed.

Acute Disease↗
PubMed1986

A psychiatric epidemiologic study of occupational lead exposure.

The association of occupational lead exposure with neuropsychiatric functioning was evaluated using data collected in 1982 in eastern Pennsylvania from 288 lead-exposed workers and 181 nonexposed subjects. Both current and cumulative exposure indices were used. After controlling for age, education, and income, few meaningful differences between exposed and control workers were found on either neuropsychologic or psychosocial variables. Dose-response analyses indicated that among lead-exposed workers, cumulative and current exposure were unrelated to neuropsychologic performance. The only meaningful associations occurred between exposure and level of conflict in interpersonal relationships. The results thus give evidence against hypotheses suggesting adverse neuropsychologic effects.

Adolescent↗