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Biomedical subjects

B Collins

Publications and source records attributed to B Collins.

At least 91 records · Page 5Linked to original sources
PubMed1977

Cardioplegia without fibrillation or defibrillation in cardiac surgery.

A group of 176 patients undergoing cardiac surgery utilizing a technique of rapid core hypothermic cardioplegia with a hyperosmotic solution is presented. A cold, 2 to 4 degrees C hyperosmotic (396 mOsm) perfusate, injected under pressure, induced cardiac arrest without fibrillation within 2 to 4 seconds in every instance. At the end of each procedure, flushing of the cold solution out of the coronary system re-establishes spontaneous normal sinus cardiac rhythm in 96% (119 of 124) of coronary surgical procedures, 69% (11 of 16) of aortic valve replacements, 62% (10 of 16) of mitral valve replacements, 55% (five of nine) of aortic valve replacements combined with multiple coronary grafting, 57% (four of seven) of mitral valve replacement combined with multiple coronary grafting, and in 50% (two of four) of double valve replacements. Combined core and topical hypothermia with ice slush used in valve replacements and combined valve with coronary operations allowed periods of total ischemia up to 134 minutes without signs of detectable myocardial damage.

Aged↗
PubMedDate not supplied

Enzyme replacement therapy in the mouse model of Pompe disease.

Deficiency of acid alpha-glucosidase (GAA) results in widespread cellular deposition of lysosomal glycogen manifesting as myopathy and cardiomyopathy. When GAA-/- mice were treated with rhGAA (20 mg/kg/week for up to 5 months), skeletal muscle cells took up little enzyme compared to liver and heart. Glycogen reduction was less than 50%, and some fibers showed little or no glycogen clearance. A dose of 100 mg/kg/week resulted in approximately 75% glycogen clearance in skeletal muscle. The enzyme reduced cardiac glycogen to undetectable levels at either dose. Skeletal muscle fibers with residual glycogen showed immunoreactivity for LAMP-1/LAMP-2, indicating that undigested glycogen remained in proliferating lysosomes. Glycogen clearance was more pronounced in type 1 fibers, and histochemical analysis suggested an increased mannose-6-phosphate receptor immunoreactivity in these fibers. Differential transport of enzyme into lysosomes may explain the strikingly uneven pattern of glycogen removal. Autophagic vacuoles, a feature of both the mouse model and the human disease, persisted despite glycogen clearance. In some groups a modest glycogen reduction was accompanied by improved muscle strength. These studies suggest that enzyme replacement therapy, although at much higher doses than in other lysosomal diseases, has the potential to reverse cardiac pathology and to reduce the glycogen level in skeletal muscle.

Animals↗
PubMedDate not supplied

Role of arachidonic acid metabolites in tumor growth inhibition by nonsteroidal antiinflammatory drugs.

PURPOSE: A murine model of squamous cell carcinoma (SCC) was used to determine the role of arachidonic acid (AA) metabolites in the growth of SCC of the head and neck. MATERIALS AND METHODS: C3H/HeJ mice bearing SCC (SCC VII) were treated with cyclooxygenase inhibitors (piroxicam and nabumetone) or a 5-lipoxygenase inhibitor (ketoconazole). Growth curves were established, and final tumor weights were measured. Following sacrifice, tumor tissue homogenates were assayed for prostaglandin E2 (PGE2) and 12-hydroxyeicosatetraenoic acid (12-HETE) by enzyme-linked immunosorbent assay (ELISA), and leukotriene B4 (LTB4) by radioimmunoassay (RIA). Inflammatory cell infiltrate was assessed histologically. RESULTS: A significant inhibition of tumor growth (P = .001) and final tumor weight (P = .002) was noted in mice treated with piroxicam and nabumetone. Inhibition of tumor growth was associated with increased tumor tissue levels of PGE2 (P = .04) and lymphocytic infiltration (P = .07). Significant inhibition of tumor growth (P = .002) and final tumor weight (P = .05) was also noted in mice treated with ketoconazole. CONCLUSION: These data suggest that both cyclooxygenase and lipoxygenase metabolites of AA affect tumor growth in this model and that inhibition of tumor growth by inhibitors of AA metabolism may be caused by an enhanced inflammatory cell response at the tumor site.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMedDate not supplied

Liposome-anchored vascular endothelial growth factor aptamers.

Nuclease-resistant aptamers identified from randomized nucleic acid libraries represent a novel class of drug candidates. Aptamers are synthesized chemically and therefore can be readily modified with functional groups that modulate their properties. We report here on the preparation, initial characterization, and functional properties of a nuclease-resistant vascular endothelial growth factor (VEGF) aptamer anchored in liposome bilayers through a lipid group on the aptamer. While the high-affinity binding to VEGF is maintained, the plasma residence time of the liposome-anchored aptamer is considerably improved compared with that of the free aptamer. The lipid group attachment and/or liposome anchoring leads to a dramatic improvement in inhibitory activity of the aptamer toward VEGF-induced endothelial cell proliferation in vitro and vascular permeability increase and angiogenesis in vivo.

Animals↗
PubMedDate not supplied

Adrenal ultrasonography correlated with histopathology in ferrets.

The adrenal glands of twenty-six, 12- to 53-month-old, ferrets without clinical signs of adrenal disease were examined and measured by ultrasonography and the findings compared with those from gross examination and histopathology. Of 51 adrenal glands examined, 27 were normal, 23 had either nodular or diffuse cortical hyperplasia and 1 had an adenocarcinoma. There was no statistically significant difference between the sonographic nor gross size of normal adrenal glands and those with hyperplasia. Moderate correlation was found between gross and sonographic measurements of length for both right (r = 0.783; p < 0.0001) and left (r = 0.609; p < 0.001) and width (p < 0.02). In female ferrets, the length, width, and depth of the right adrenal gland sonographically measured (mean +/- sd) 7.5 +/- 1.2 mm, 3.7 +/- 0.6 mm, 2.8 +/- 0.4 mm, respectively, and the left measured 7.4 +/- 1.0 mm, 3.7 +/- 0.4 mm, 2.8 +/- 0.4 mm; in males, the right adrenal measured 8.9 +/- 1.6 mm, 3.8 +/- 0.6 mm, 3.0 +/- 0.8 mm and the left measured 8.6 +/- 1.2 mm, 4.2 +/- 0.6 mm, 3.0 +/- 0.6 mm. Accessory adrenal tissue was not identified during the sonographic examination but was grossly found in 10 of the ferrets. It was associated with either the right, left or both adrenal glands.

Adenocarcinoma↗
PubMedDate not supplied

Pleomorphic adenoma (benign mixed tumor) of the trachea.

A 15-year-old "asthmatic" found to have a pleomorphic adenoma of the trachea was treated by staged CO2 laser excision. Primary tracheal tumors, the clinicopathologic features of mixed tumor in this rare location, and therapeutic options are briefly reviewed. Immunohistochemical stains for cytokeratin, S-100 protein, and glial fibrillary acidic protein are reliable methods of evaluating component cell types in pleomorphic adenoma, but immunohistochemical evidence has not resolved the issue of tumor histogenesis.

Adolescent↗
PubMedDate not supplied

Three hospitals' survey experiences.

The Joint Commission on Accreditation of Healthcare Organizations has made major alterations in its standards and survey process under the Agenda for Change, by emphasizing cross-functional healthcare. The Joint Commission published the changes in its 1994 Accreditation Manual for Hospitals, under which criteria these hospitals were surveyed. Surveyors concentrated on evaluating the following major issues: care of patients, particularly restraint policies and procedures; uniform performance of processes, particularly as related to conscious sedation; staff competency; and process improvement. The authors detail why a thorough, detailed preparation for the document review session is essential for a successful survey.

Accreditation↗