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BACKGROUND AND PURPOSE: Novel stratagems to improve the efficacy of platinum coils in occluding cerebral aneurysms have primarily involved coating coils with materials thought likely to provoke more desirable histologic reactions. No investigations to date, however, have evaluated the utility of gold or vitronectin coatings, despite known endovascular histologic effects of these agents, which may be favorable for treating cerebral aneurysms. This study was conducted to evaluate the degree of endovascular histologic change associated with ultrathin gold- or vitronectin-coated platinum coils. It was hypothesized that such coatings would increase intra-aneurysmal intimal hyperplasia and the degree of luminal occlusion compared with standard platinum coils. MATERIALS AND METHODS: The ligated carotid artery rat model was used to study 4 different aneurysm coil conditions: no coil (sham-surgery controls), uncoated platinum coil, and gold- or vitronectin-coated platinum coil. Two weeks postimplantation, the aneurysms were harvested and stained with hematoxylin-eosin. Slides were evaluated for the degree of neointimal response by a pathologist blinded to treatment. Additional quantitative evaluation was performed blindly by using the ratio of intimal-to-luminal cross-sectional area. RESULTS: A gold- or vitronectin-coated platinum aneurysm coil produced a statistically significant increase in neointimal response compared with a sham (no coil). Arterial segments treated with gold-coated platinum coils also demonstrated a statistically significant 100% increase in neointimal response compared with those treated with bare platinum coils. CONCLUSIONS: In concordance with our hypothesis, ultrathin coatings of gold provoked a neointimal response and degree of luminal occlusion greater than that of plain platinum aneurysm coils in a rat arterial occlusion model.

Recent investigations have shown numerous fatty microemboli, which we previously termed small capillary and arteriolar dilatations (SCADs), in brain microvessels of patients who died after cardiac surgery assisted by cardiopulmonary bypass (CPB). The hypothesis of this study was that extraneous trace elements such as aluminum (Al) and silicon (Si) might be contaminating the blood and causing the formation of SCADs or coating the SCADs already formed in the extracorporeal circulation during CPB. Small capillary and arteriolar dilatations were identified in thick celloidin sections of the brains of 8 patients who died after cardiac surgery supported with a membrane oxygenator, and of 2 dogs that underwent CPB with a bubble oxygenator. The sections were infiltrated with Spurr's embedding medium for electron microscopy. Resin sections 0.5 microm thick were placed on 100-mesh copper grids and analyzed with laser microprobe mass spectrometry. Brain sections without SCADs from 3 patients (controls) whose deaths were not related to cardiac surgery were processed similarly. In SCADs and nearby neuropil sites of the 8 patients who had cardiac surgery, both Al and Si values were higher than in the neuropil, including vessels of the 3 controls. Si values were also high in the 2 dogs, in which a bubble oxygenator was used. Our results indicate that contamination with Al and Si continues to occur during cardiac surgery assisted by CPB. Our data also suggest that switching to membrane oxygenators from bubble oxygenators for CPB may have reduced Si contamination of blood. Further refinements of CPB aimed at eliminating microemboli formation and Al and Si entry into the circulation are warranted.

To examine the vascular supply and architecture of the germinal matrix in the preterm neonatal brain and to determine whether veins or arterioles are the source of germinal matrix hemorrhage.Brains from eight preterm neonates (24 to 35 weeks' gestation) and two full-term infants were fixed in alcohol, embedded in celloidin, sectioned at 100- and 500-micron thicknesses, stained for alkaline phosphatase, and examined with light microscopy. High-resolution contact radiographs of 500-micron-thick sections were also mounted on glass slides for microscopic examination.The upper and middle regions of the germinal matrix are supplied by branches of the lateral striate arteries, whereas the inferior part is supplied by branches of the recurrent artery of Heubner. In brain sections from four of the preterm infants, we found 15 circumscribed hemorrhagic foci within the germinal matrix. The largest was 5 mm in diameter; the smallest, 1 mm. All hemorrhages but one were closely associated with veins, with significant involvement of the perivenous space. The other hemorrhage appeared to be associated with an arteriole. In term and preterm infants, we found no arteriolar-to-arteriolar shunts, precapillary arteriolar-to-venules shunts, or vascular rete. At all gestational ages, the terminal vascular bed had only conventional branchings and connections.In preterm neonates, staining for endogenous alkaline phosphatase allows visual differentiation between afferent and efferent vessels. Germinal matrix hemorrhage in preterm neonates is primarily venous in origin. A hemorrhage can tunnel along the venous perivascular space, collapsing the vein and rupturing the tethered connecting tributaries. Extravasation of blood from the arterial circulation appears to be much less common.

The influence of the prenatal and postnatal maternal environment on stroke susceptibility was evaluated by reciprocally crossing the spontaneously hypertensive (SHR) and the Dahl salt-sensitive (SS/Jr) inbred rat strains to produce reciprocal F1 hybrids that were nurtured, respectively, during prenatal and postnatal life by SHR or SS/Jr mothers. Following placement on a high-salt diet containing 8% NaCl at 35 days of age, F1 rats reared by SHR mothers had shorter survival times and were more likely to die with cerebral hemorrhage than F1s reared by SS/Jrs. Across reciprocal F1 female groups, enhanced susceptibility to stroke was associated with greater elevations of systolic blood pressure, but this association was not seen across reciprocal F1 male groups. There was also an association between blood pressure and stroke within each F1/gender subgroup: Rats eventually suffering strokes developed higher blood pressure after placement on the high-salt diet than rats that did not suffer stroke. Lower day 35 body weights (before exposure to the high-salt diet) were associated with greater likelihood of stroke both across the reciprocal F1 groups, and within three of the four F1/gender subgroups. The differences in stroke susceptibility between the reciprocal F1 groupings may be due to systematic differences in the prenatal and/or postnatal environments of SHR and SS/Jr mothers and may be mediated by variations in the nutritive capacity of the two inbred mothers.

In an ongoing study of brain microvasculature in humans at autopsy, we had the opportunity to analyze the overall scheme of this vascular supply. The native endothelial membrane enzyme, alkaline phosphatase, is used to precipitate black lead sulfide salt in the vessel wall, rendering the brain microvasculature visible by both light microscopy and microradiography. There are six distinct patterns of intraparenchymal afferent blood supply to the supratentorial brain: short arterioles from a single source (e.g., those in the cortex); short- to intermediate-length arterioles, single source (anterior two-thirds of the corpus callosum); short- to intermediate length arterioles and arteries, dual source (subcortical U fibers); intermediate-length arterioles and arteries, triple source (extreme/external capsule and claustrum); long arteries and arterioles, single source (centrum semiovale); and large, long muscular arteries, single source (thalamus and basal ganglia). The nature of this arrangement offers some protection to certain regions of the cerebrum from circulatory challenges such as hypotension, while leaving other areas vulnerable. The distal arterioles supplying two of these protected regions, the U-fiber area and the extreme/external capsule and claustrum area, also exhibit the feature of interdigitation, which can offer additional collateral potential from one arteriolar territory to the next. Aging, hypertension, diabetes mellitus, and atherosclerosis can have a significant impact on brain microcirculation. The way in which vascular patterns dictate the distribution of these effects is discussed. The ability to stain the cerebral microvessels and demonstrate the finer points of their patterns in sections and microradiographs has enabled us to resolve some long-standing questions about vascular connections and directions.(ABSTRACT TRUNCATED AT 250 WORDS)

The fine structure of 3 primitive neuroectodermal neoplasms of the cerebral hemispheres was studied. The predominant tumor cells were undifferentiated cells with prominent nuclei and scanty cytoplasm containing few organelles. Ultrastructural evidence suggesting differentiation into ependymal, neuronal and possibly astrocytic elements was also present. This study suggests that the cell of origin of this tumor is a primitive multipotential cell of the cerebrum.

The corpus callosum exhibits several unusual features: arteriole-venule pairs, perivascular fibrous alae, and recurrent companion arterioles. These and other anatomic aspects are compared and contrasted with those of the centrum semiovale. Vascular changes occurring with aging or hypertension, commonly seen in the centrum semiovale, rarely develop in the corpus callosum. The vascular supply to the central zone of the genu and body of the corpus callosum, via short penetrating arterioles, is similar to that of the cerebral cortex, whereas the vascular supply to the extreme lateral corpus callosum, centrum semiovale, and basal ganglia is substantially carried by long end-arteries. When observed critically, the anatomic features of the corpus callosum may explain such clinically observed phenomena as its relative resistance to flow of fluid masses, radiation injury, Binswanger disease, lacunar infarction, hypoxia, and hypoperfusion.

Myenteric plexuses and smooth muscle of the pylorus obtained by biopsy at pyloro myotomy in 5 infants with hypertrophic pyloric stenosis were studied by electron microscopy. Animal controls consisted of pyloruses from 2 infant and 2 adult rabbits and 2 adult rats. The principal findings in the plexuses of the patients were moderate numbers of variably sized, swollen degenerating axons that contained dense bodies, lamellated figures, vacuoles, granular or fibrillar material, and swollen mitochondria. The significance of this alteration in the etiology and pathogenesis of this disorder is not clear. Neurons in the plexuses showed no definite abnormalities. Although these findings do not confirm previous light microscopic observation of neuronal changes in the pyloric myenteric plexuses, they do not exclude a neurogenic mechanism for this disorder. The presence of small immature neurons and large mature neurons suggests that neuronal maturation and development in infantile hypertrophic pyloric stenosis are not impaired as previously reported. No ultrastructural changes were found in interstitial cells of the myenteric plexuses. Except for hypertrophy of the circular smooth muscle layers, no specific alterations were found in muscle fibers of the pylorus.

Yersinia enterocolitica, a gram negative aerobic non-haemolytic bacillus, has been identified as a cause of meningitis only once before and the neuropathological features of Y. enterocolitica meningitis have not been reported in the literature. We describe the pathological features of a case of acute fatal meningitis caused by Y. enterocolitica, serotype 0:18, in a 47-year-old male alcoholic with cirrhosis. The organism presumably reached the meninges via the blood stream from the abdominal cavity. Intravascular fibrin thrombi, both recent and organising, were associated with multiple foci of necrosis in the brain. In spite of vigorous antibiotic therapy for three weeks the organism was cultured from the brain at autopsy. Among the various infections caused by Y. enterocolitica, meningitis appears to be the most difficult to eradicate.

A case of Crohn's colitis is described in a patient who demonstrated multiple extraintestinal complications, including erythema nodosum, pyoderma gangrenosum, and aphthous oral ulcerations. Our patient simultaneously developed an unusual vasculitis in muscle. Small vessels were affected by necrosis, and polymorphonuclear leukocyte infiltration was appreciated. Leukocytoclastic was suggested by these features and the additional finding of small amounts of nuclear debris. A strong immunofluorescence to antihuman C3 was demonstrated in the affected vessel walls. We did not find circulating IgG immune complexes in serum with the Raji cell assay. The implication of the finding of leukocytoclastic vasculitis in muscle, associated with Crohn's colitis, is discussed.

A 57 year old white man with aortic insufficiency and previously undiagnosed ankylosing spondylitis, who developed subacute bacterial endocarditis (SBE), is described. Emergency aortic valve replacement was necessary, and the aortic valve pathology showed diffusely fibrosed and thickened valve leaflets with bacterial vegetations. This is the first recorded case of SBE in ankylosing spondylitis.