Shope rabbit papillorna-carcinoma complex a model system of HPV infections

To the busy, practicing dermatologist, an animal model system may appear to offer little benefit to patient diagnosis or management; however, animal model systems often can provide answers to vexing clinical problems that cannot be approached in patient studies because of ethical restrictions or logistic problems. Animal models are imperfect substitutes for human diseases; but because they share similar mechanisms, an animal model can provide an opportunity to test hypotheses that contribute to an understanding of the human counterparts.

The Shope rabbit papilloma is remarkably similar in etiology and mechanism to many naturally occurring lesions induced by human papillomaviruses. In that sense, the Shope system can contribute to an understanding of human wart-virus infections. In a broader context, the Shope papilloma-carcinoma complex can provide an understanding of the determinants of neoplastic progression and of host interactions with neoplastic tissue.

The purpose of this report will be to review some of the more important aspects of this experimental tumor system, especially those that are relevant to clinical situations. This review will be limited in scope. For more detailed coverage, the reader is referred to another article which we published elsewhere.¹     

Effects of morphine sulfate on human coronary blood flow

Because morphine causes coronary vasoconstriction in conscious dogs, human coronary blood flow was measured with the thermodilution technique before and after administration of morphine sulfate, 0.2 mg/kg body weight (maximum 15 mg) intravenously, in 10 patients to determine if the canine experience is clinically applicable. Coronary blood flow increased from a baseline value of 104.4 +/- 13.4 (mean +/- standard error of the mean) to 113.0 +/- 17.4 ml/min (difference not significant) 15 minutes after the administration of morphine. Baseline coronary vascular resistance was 1.14 +/- 0.19 mm Hg/ml/min; 15 minutes after morphine administration the resistance value was 1.02 +/- 0.17 (P less than 0.025). There was no significant change between baseline values and values 15 minutes after morphine administration in systemic mean arterial pressure (98.2 +/- 5.3 to 92.8 +/- 4.7 mm Hg); heart rate (69.5 +/- 3.5 to 72.6 +/- 3.4 beats/min), left ventricular ejection time (0.345 +/- 0.009 to 0.342 +/- 0.007 second) or tension-time index (2,324 +/- 128 to 2,291 +/- 149 mm Hg/sec per min). The slight coronary vasodilation noted after morphine administration in this study is in marked contrast to the significant coronary vasoconstriction demonstrated in the unanesthetized dog.     

Scintigraphic determination of ventricular function and coronary perfusion in long-distance runners

Left ventricular function and coronary perfusion were evaluated with rest-exercise gated blood pool and stress-redistribution thallium scans in a group of long-distance runners and compared to a group of catheterization-proved normal subjects. Exercise duration, work load, and oxygen consumption were significantly greater for long-distance runners. Rest end-diastolic volume (EDV), end-systolic volume (ESV), and stroke volumes (SV) were significantly larger in long-distance runners than in control subjects, while ejection fraction (EF), cardiac index (CI), and ejection rate were similar in both groups. Exercise EDV increased and ESV decreased, producing an increase in SV and EF in long-distance runners. Exercise EDV did not change and ESV decreased less, producing lesser increase in SV and EF in the control group. Qualitative evaluation of thallium scans showed apparent perfusion defects with normal redistribution in six myocardial segments in five long-distance runners. Quantitative evaluation demonstrated initial defects, which persisted on delay scans, but were associated with normal relative redistribution in three ventricular walls in three long-distance runners. In conclusion, left ventricular reserve function was greater in long-distance runners than in control subjects. Endurance exercise can be associated with apparent myocardial perfusion defects, which may be due to uneven ventricular hypertrophy resulting from the pressure and volume loads imposed by exercise.     

Collateral Circulation Testing of the Hand– Is it Relevant Now? A Narrative Review

Testing for collateral circulation of the hand before any radial artery procedure has been a subject of many controversies. Neither the Allen's test (AT) nor the plethysmography based Barbeau test, adequately and reliably test for collateral circulation. With growing interest in radial approaches for vascular procedures, its common use for arterial monitoring and blood gas sampling, there has been a growing interest in the relevance of assessing collateral hand circulation. Multiple studies now refute the utility of collateral testing, yet it continues to be propagated as an essential triaging assessment tool by educators. Allen's, or modified Allen tests (MAT) are operator dependent and often subjected to observational bias. Barbeau test is more objective, however, it fails to show added benefit in assessing pre-procedural patency. Despite studies questioning the validity of collateral circulation assessment, these tests continue to preclude radial approach. There is no standardization for being considered an abnormal test across literature and the significance of an abnormal test translating into a clinical outcome has not been investigated in prior studies. This may be attributed to the robust vascular supply of the hand, connections at the digital circulation level and vessel recruitment in an event of occlusion. We reviewed this topic extensively and make an argument that non-invasive collateral testing should be abandoned as a triage tool for radial artery procedures such as arterial punctures, arterial monitoring, and transradial vascular procedures.     

Cord blood fatty acid composition in infants and in their mothers during the third trimester

Since essential fatty acids are required for normal brain development, we studied plasma lipids and EFA levels in 16 postpartum mothers (28 to 44 weeks) and in the umbilical vein and artery of 32 newborn infants. Groups of eight 24 to 33-, 34 to 37-, 38 to 42-, and 43 to 44-week-old infants were studied. Plasma fatty acid composition was studied in PL, CE, TG, and FFA by thin-layer and gas-liquid chromatography. Increased values for PL, CE, and TG (P less than 0.001) were noted in maternal plasma compared to cord plasma; linoleic acid was lower (P less than 0.001) in cord plasma PL, CE, and FA. EFA derivatives dihomo-gamma-linolenic, arachidonic, and docosahexaenoic acids were higher in cord plasma (P less than 0.001). Total polyenoic EFA increased with advanced gestation, and at term, was close to maternal levels. delta-5,8,11-eicosatrienoic acid (elevated in EFA deficiency) was elevated in cord plasma as compared with maternal values (P less than 0.001); other criteria of EFA deficiency were absent. These data indicate that fetal EFAs are elongated and desaturated during the third trimester. These higher polyenoic acids may incorporate into lipids in the developing CNS. The lower linoleic acid levels in the fetus may be important to the transplacental transport of EFA.