The effects of cardiopulmonary bypass and cold cardioplegia on coronary flow velocity and the reactive hyperemic response in patients and dogs

In normal coronary arteries, reactive hyperemic responses to a 20-second occlusion, an index of coronary reserve, usually demonstrate a peak-to-resting flow velocity ratio of 4:1 or more. Most intraoperative studies that have assessed reactive hyperemic responses in bypassed vessels have reported peak-to-resting flow velocity ratios of 2:1 or less following a 20-second occlusion. These decreased reactive hyperemic responses could be due to coronary vasodilatation after cardiopulmonary bypass or to an inadequate physiological result of the surgical procedure. In 14 patients with angiographically normal coronary arteries, the peak-to-resting flow velocity ratio following a 20-second coronary occlusion decreased significantly (p less than 0.05) from 4.4 +/- 0.2 (mean +/- standard error) before bypass to 3.0 +/- 0.3 after bypass. In a similar dog model, the peak-to-resting flow velocity ratio decreased by 36 to 52% during the first hour following one hour of cardiopulmonary bypass and cardioplegia. During the same period, left ventricular perfusion increased 21 to 30%, mean arterial pressure and coronary vascular resistance decreased, and myocardial oxygen consumption was unchanged. In a second group of dogs studied for the effects of duration (200 to 240 minutes) of anesthesia and thoracotomy alone, peak-to-resting flow velocity ratio was significantly lower. These clinical and experimental studies suggest that major coronary vasodilatation occurs early following cardiopulmonary bypass and cold cardioplegia, and may contribute to the blunted coronary reactive hyperemic responses reported during this time. Consequently, an intraoperative peak-to-resting flow velocity ratio of 3:1 for bypassed coronary arteries may represent an excellent physiological result.     

Cinefluoroscopic evaluation of periprosthetic cardiac valve regurgitation

The results of cinefluoroscopic evaluation in 509 patients in whom there was no evidence of prosthetic mitral or aortic valve regurgitation were compared with those in 41 patients who had perivalvular aortic or mitral regurgitation. Rotational motion of the base ring of each prosthesis (base-ring tilt) was measured in at least two views. A base-ring tilt of 7 degrees or more for aortic prostheses or 11 degrees or more for mitral prostheses was associated with an increased incidence of significant perivalvular regurgitation. Likewise, in patients who had multiple studies, a change between studies in base-ring tilt of 4 degrees or more for aortic prostheses or 5 degrees or more for mitral prostheses was associated with significant perivalvular regurgitation. These data suggest that the presence of either an abnormal base-ring tilt or an abnormal increase in base-ring tilt is strong, supportive evidence of partial prosthetic valve dehiscence.     

Cognition in stroke

Introduction – Despite the current interest in criteria for vascular dementia, global, as opposed to focal, cognitive change after cerebral infarction has rarely been studied. Material and methods – We documented the neuropsychological changes one to three weeks and three months post infarct in 25 unselected patients with acute, first cerebral infarcts. Results – Improvements were seen in processes thought to have a large subcortical component and in those mediated in the right hemisphere. Memory was relatively lightly affected. Conclusion – The minimal deficits seen in memory and the predominance of subcortical changes are at variance with the currently suggested criteria for vascular dementia. Further data of this kind are needed before firm criteria can be proposed for the global pattern of cognitive changes expected in vascular dementia.     

Myeloradiculopathy associated with wasp sting

A 12-year-old girl developed a reversible myeloradiculopathy 1 week after a wasp sting. Delayed neurologic hypersensitivity reactions to Hymenopteran stings occur primarily in adults. Reactions involving both the peripheral and central nervous systems are extremely rare and have never been reported in a child. The mechanisms underlying this uncommon reaction may be related to age-dependent differences in immunologic responses.     

Dual function nitroimidazoles less toxic than RSU 1069: selection of candidate drugs for clinical trial (RB 6145 and/or PD 130908.

Following the toxicity and synthetic difficulties encountered with the hypoxic cell radiosensitizer RSU 1069, efforts have focused on development of a superior analogue. Two compounds, RB 6145 and PD 130908, have emerged from this program which overcome the instability and synthetic problems associated with RSU 1069 while retaining favorable biological activity. Both agents show comparable radiosensitizing activity to RSU 1069 following oral or i.p. administration to mice bearing the KHT or RIF-1 tumors. Sensitizing efficiency is about 10 X greater than that observed for misonidazole or etanidazole. Toxicity toward hypoxic tumor cells in vivo is demonstrated by clamping tumors (for 60 min) following administration of PD 130908 or RB 6145. Both are effective hypoxic cytotoxins, but less potent than RSU 1069. Systemic toxicity is substantially reduced following oral drug administration. Further, doses achievable following fractionated drug treatments are sufficiently high to produce significant levels of radiosensitization.     

Mutated c-Ha-ras oncogene alters cytokeratin expression in the human breast epithelial cell line MCF-10A.

MCF-10A, a spontaneously immortalized human breast epithelial cell line, has been transformed by transfection with the mutated c-Ha-ras oncogene obtained from T24 carcinoma cells. The pattern of cytokeratin expression was studied in MCF-10A cells in comparison with plasmid transfected or MCF-10Aneo cells, normal ras proto oncogene transfected or MCF-10AneoN cells, and transformed or MCF-10AneoT cells. Cytokeratin expression was studied by western immunoblot of total cellular proteins separated by two-dimensional gel electrophoresis. Blots with cytokeratin specific AE1 and AE3 antibodies showed identical molecular weight species of cytokeratins in MCF-10A, MCF-10Aneo, MCF-10AneoN, and MCF-10AneoT cells; however, in MCF-10AneoT cells, the intensity of immunostaining and the number of immunoreactive phosphorylated polypeptides keratins 7, 8, 15, and 16 was decreased. It was concluded that c-Ha-ras oncogene-induced transformation alters quantitatively the cytokeratin pattern of human breast epithelial cells and that these changes could explain some of the morphologic alterations observed in c-Ha-ras transformed cells.     

Adjustment to spinal cord injury: stage theory revisited

To better understand adjustment following spinal cord injury (SCI), 106 subjects from two samples (N = 53 each) were administered the SCL-90-R, a symptom checklist, and the Multidimensional Health Locus of Control scales. Sample 1 subjects were admitted for rehabilitation during 1981 to 1982 and sample 2 subjects were admitted during 1984 to 1986. Sample 2 subjects entered rehabilitation programs more quickly after injury and reported more anxiety, phobic anxiety, and hostility than sample 1 subjects. Within each sample, there was no evidence for a relationship between age or time since injury and health beliefs or psychological distress. This study does not support stage theory for adjustment after catastrophic injury, but does suggest the importance of understanding the impact of social policy changes in adjustment following spinal cord injury.