Sinoatrial node arteriosclerosis in two young dogs.

Two 11-month-old 7-kg unrelated female Beagles had clinical signs referable to the cardiovascular system. Histologic studies in both dogs revealed strikingly similar findings of sclerosis of the arteries of the sinoatrial node. Histologic changes included intimal thickening and fibrosis, with marked luminal narrowing; medial hypertrophy, fibrosis, and smooth muscle cell proliferation; and elastic fiber disruption and reduplication. Possible differential diagnoses for this condition included systemic necrotizing vasculitis (canine pain syndrome), coronary polyarteritis, and atherosclerosis.

Intraventricular and subarachnoid hemorrhage resulting from necrotizing vasculitis of the choroid plexus in a patient with Churg-Strauss syndrome.

Neurologic symptoms are common in patients with the Churg-Strauss syndrome and often manifest as a peripheral neuropathy of the mononeuritis multiplex type secondary to vasculitis. Reports of central nervous system involvement is less frequent and ranges from psychiatric disturbances to cerebral hemorrhage. We report the first case of pathologically documented vasculitis involving the choroid plexus causing massive and fatal intraventricular and subarachnoid hemorrhages in a 47-year-old patient with Churg-Strauss syndrome.

Cardiovascular malformations induced by bromodeoxyuridine in the chick embryo.

For the study of morphogenesis and early embryonic development, 5-bromodeoxyuridine (BUdR), a halogenated analogue of thymidine, is incorporated into replicating DNA and serves as a valuable tool. To study the teratogenicity of BUdR on the developing chick cardiovascular system, we topically administered graded doses of BUdR (32.6-325.6 nmol) in ovo during Hamburger-Hamilton stages 15 to 16. We also administered to a parallel group of embryos corresponding nanomole doses of thymidine during identical stages of development. In the thymidine-treated group, survival rates and cardiovascular anomaly rates did not differ statistically from those in the chick Ringer's control group. Both survival rates and cardiovascular anomaly rates in the BudR-treated group were dose-responsive. Among 78 embryos with cardiovascular anomalies induced by BUdR, vascular malformations were found in 96%. These anomalies included interruption of the right fourth aortic arch, absence or hypoplasia of the right and/or left sixth aortic arch, and persistence of the left fourth aortic arch. Interruption of the right fourth aortic arch was always associated with intracardiac anomalies. Intracardiac anomalies were found in 54% of the embryos; these included ventricular septal defect, double outlet right ventricle, and persistent truncus arteriosus. Subclavian artery malformations were noted in 95% of the embryos. Possible mechanisms for BUdR-induced malformations in the cardiovascular system of the chick are discussed.

Ethyl alcohol-induced cardiovascular malformations in the chick embryo.

Chick embryos incubated for 72-80 hours were exposed to various volumes (0.20-0.40 m1/egg) of 50% ethyl alcohol. Examination of embryos at day 14 of incubation showed that higher doses of ethanol decreased the survival rate of embryos compared with control embryos. Three major categories of cardiovascular malformations were observed in this study: intracardiac anomalies characterized primarily by isolated ventricular septal defect, ventricular septal defect with overriding aorta, double outlet right ventricle or common aorticopulmonary trunk; aortic arch anomalies; and subclavian artery anomalies. Frequencies of embryos with intracardiac anomalies were equal to or greater than 64.8% in the six groups exposed to ethanol. Administration of ethanol also induced high frequencies of embryos with subclavian artery anomalies (11.2-89.1%). Absence or hypoplasia of the right and/or left secondary subclavian artery was commonly associated with persistence of the corresponding primary subclavian artery. Bilateral absence and/or hypoplasia of the secondary subclavian arteries was more common than unilateral anomalies, whereas absence of the left secondary subclavian artery was more commonly observed than an absent right secondary subclavian artery. No embryos in the two control groups combined (n = 94) demonstrated aortic arch or subclavian artery anomalies.

Newborn infant with del(9)(pter----q32:) and multiple congenital anomalies including arrhinencephaly, cardiac malformations, and rudimentary ears.

A deletion of the long arm of chromosome 9(pter----q32:) in a newborn infant at 38 weeks of gestation was associated with a syndrome of arrhinencephaly, rudimentary ears, hypoplastic lungs and ureters, redundant nuchal skin folds, and congenital heart defects. Other findings included a Sydney line, macrocephaly, talipes equinovarus, oligohydramnios, and amnion nodosum. Detailed pathologic observations and the chromosome abnormality are described.

The causes and underlying developmental mechanisms of congenital cardiovascular malformations: a critical review.

Cardiovascular malformations are the second most common type of birth defect, occurring in 5-8/1,000 livebirths with a still higher prevalence among stillborn infants and spontaneously aborted embryos and fetuses. Dealing effectively with the high frequency of heart defects means reducing the incidence of cardiac malformations in the world. In this paper we cite some of the genetic and environmental risk factors associated with congenital cardiovascular malformations, describe the putative biochemical nature of the genetic predisposition relative to environmentally induced teratogenesis, and either support or discourage the use of available methods as strategies in preventing cardiovascular anomalies.

The effects of L- and D-carnitine administration on cardiovascular development of the chick embryo.

A single 1.0-ml volume of L- or D-carnitine solution, at several selected mmole concentrations, was applied to the extraembryonic membranes of 3- and 4-day chick embryos in ovo. Hamburger-Hamilton stages of chick development ranged from 17 to 23. During the 17-18th days of incubation, embryos were dissected, and both survival and intracardiac anomaly rates were determined. Only at extremely high doses, both stereoisomers of carnitine exhibited a statistically significant toxigenic effect (p less than 0.001) as measured by a sharp decrease in survival rate when compared to chick Ringer's saline controls. Furthermore, since the anomaly rates became significant only near the LD50's, this indicated that intracardiac anomalies were induced only at toxic doses. Therefore, it is suggested that cardiovascular teratogenicity may be the result of toxicity. Below the LD50, anomaly rates were not significantly different from those of control embryos. In comparison, L- and D-carnitine were significantly different from one another (p less than 0.001) both in survival rate and percent affected embryos at a dose of 0.5 mmole. In summary, exogenous carnitine administration to the chick embryo does not appear to be deleterious to the developing cardiovascular system.

Changes in carnitine levels in the embryonic chick heart during development.

Carnitine levels in the embryonic chick heart were measured. The amount of total carnitine, free plus short chain acyl carnitine (acid-soluble fraction), and long chain acyl carnitine (acid-insoluble fraction) were examined at days 7, 11, 17, and 21 of incubation. These concentrations were found to correspond favorably with data from previous investigators with regard to variations in palmitoylcarnitine transferase enzyme activity, mitochondrial chain elongation activity, and palmitic acid oxidation.

The influence of ambient and viewbox light upon visual detection of low-contrast targets in a radiograph.

Thirty-one observers (five radiologists, five radiology residents, and 21 nonradiologists) examined low-contrast images of 13 polyvinylchloride cylinders. Image density ranged from 1.91 to 2.05 OD units with a background density of 2.09 OD units. The experiment tested visual performance under various clinically relevant lighting conditions by asking the observers to locate a groove in each cylinder. Use of low ambient light and restricting light from surrounding veiwboxes significantly improved performance (P less than 0.0001). In general, the less the amount of extraneous light, the higher was the detection rate. Some observers did significantly better than others. Reduced scattering of light within the eye is suggested as an explanation for their increased performance.