Diagnosis of brain death by common carotid artery velocity waveform analysis.

In addition to neurologic criteria, some test of cessation of brain blood flow is recommended before diagnosing "brain death." Cerebral arteriography, radionuclide scintigraphy, and contrast computed axial tomography, though reliable, possess significant practical limitations. Analysis of the dimensions and contours of common carotid Doppler velocity tracings of brain-dead patients has identified qualitative and quantitative differences not only from normal subjects, but also from patients with complete atheromatous carotid occlusion and from those unconscious after brain injury. Though accurate separation was initially made using computer-assisted classification function analysis, a simplified algorithmic approach using only three velocity waveform variables has been developed without loss of accuracy. The speed, simplicity, portability, and inexpensiveness of this approach commend its use.

Posterior corneal pigmentation and fibrous proliferation by iris melanocytes.

Pigmentation of the posterior corneal surface results either from endothelial phagocytosis of free melanin pigment or from the presence of iris melanocytes, iris pigment epithelial cells, or pigment-containing macrophages on the posterior corneal surface. Although this is occasionally seen clinically, it is more often noted at histopathologic evaluation after operative or accidental ocular trauma. Three cases of posterior corneal pigmentation by iris melanocytes are reported. In one case, the pigmented membrane was the major cause of considerable visual impairment and was documented with clinical photographs and specular microscopy. By light and electron microscopy, all three cases were consistent with findings of posterior corneal pigmentation by iris stromal melanocytes that had acquired endothelium-like morphologic characteristics. We also consider the possible contribution of these melanocytes to posterior collagen layers of the cornea.

The use of velocity wave form analysis in the diagnosis of carotid artery occlusive disease.

Velocity wave form analysis (VWFA) was carried out on 75 velocity tracings recorded from the common carotid artery with a continuous wave Doppler. Grouped according to clinical status, there were 20 young "normals" (I), 18 old "normals" (II), 15 stenoses of less than 50% diameter (III), 13 stenoses of greater than 50% (IV), and nine complete occlusions (V). Five of the nine dimesnions analyzed were found to be more discriminating than the others. Using these dimensions in an equation derived by discriminant analysis, the "score" of each tracing placed it into the appropriate clinical category with 95% accuracy. The accuracy rate of separating normal, stenosed, and occluded carotids was 100%. The accuracy of VWFA was limited (82%) only in discriminating between greater than and less less than 50% stenosis by diameter. Twenty-one of the 37 patients identified by VWFA as having carotid artery occlusive disease (CAOD) had normal supraorbital artery Doppler tests. Highly significant improvements in the velocity wave form of 10 carotid arteries were produced by endarterectomy.

The vomeronasal organ of Jacobson in the human embryo and fetus.

The early morphogenesis of the vomeronasal organ of Jacobson is documented in the human embryo and early fetus using light and electron micrographs. Differences between its structure and that of the olfactory epithelium are discussed.

Extra-aural spread of acquired cholesteatoma. A report of two unique cases.

The osteolytic effect of inflamed cholesteatoma can result in destruction of the bony confines of the middle ear and mastoid. Although extramastoid extension of cholesteatoma is possible through this mechanism, it is rarely seen by the otolaryngologist. We present two cases of extra-aural spread of cholesteatoma. One case illustrates the necessity of a full neuroradiologic examination of patients with neurologic findings and cholesteatoma prior to exploration of the middle ear and mastoid.

Treatment of antibiotic-associated pseudomembranous colitis with cholestyramine resin.

Pseudomembranous colitis (PMC) is an infrequent but serious complication of oral and intravenous antibiotic therapy. Twelve patients with antibiotic-associated PMC, documented by sigmoidoscopy and rectal biopsy, were treated with cholestyramine resin. The mean time from the institution of therapy to cessation of diarrhea was 2.1 days. The response interval bore no relationship to the time symptoms were present prior to therapy. Complete resolution of sigmoidoscopic and histologic evidence of PMC usually accompanied or followed cessation of diarrhea. Obstipation was reported in 5 of 12 patients as a side effect of cholestyramine treatment. Therapy should be continued for up to five days after cessation of diarrhea to prevent recurrence of active PMC. Cholestyramine resin is shown to be an effective treatment for antibiotic-associated PMC.