Variable coordination modes of hydrotris(3-isopropyl-4-bromopyrazolyl)borate (Tp') in Fe(II), Mn(II), Cr(II), and Cr(III) Complexes: formation of MTp'Cl (M = Fe and Mn), structural isomerism in CrTp'(2), and the observation of Tp' (-) as an uncoordinated anion.

The syntheses of the 4-coordinate Tp'MCl complexes (where M = Fe (1), Mn (2); and Tp' = hydrotris(3-isopropyl-4-bromopyrazolyl)borate) are described. The single-crystal X-ray structures show that the metal centers have distorted tetrahedral coordination. Analogous reaction of CrCl(2)(MeCN)(2) with TlTp' gave Cr(kappa(3)-Tp')(kappa(2)-Tp') (3) as the initial product. The 5-coordinate structure was assigned by single-crystal X-ray crystallography, and it was found that the kappa(3) ligand had isomerized to hydro(3-isopropyl-4-bromopyrazolyl)(2)(5-isopropyl-4-bromopyrazolyl)borate). 3 is labile in solution: in pentane it slowly converts to the 6-coordinate isomer Cr(kappa(3)-Tp')(2) (4), whose structure was determined by X-ray crystallography. In 4 both ligands are isomerized. Both 3 and 4 display Jahn-Teller distorted structures expected for high-spin d(4) configurations. Variable temperature magnetic susceptibility measurements confirm that 1, 2, and 3 all have high-spin electronic configurations in the range 5-300 K. In benzene solution 3 decomposes; one product [Cr(kappa(3)-Tp')(2)](+)[Tp'](-) (5), was identified by X-ray crystallography. 5 contains a pseudooctahedral Cr(III) cation with both ligands in the isomerized form and an uncoordinated Tp' ligand as counterion. Mechanistic studies reveal that this reaction is light rather than heat induced. IR spectroscopy is utilized to confirm the ligand hapticity in all complexes from the value of nu(B)(-)(H), and comparison is made with similar compounds.

Hypothermia: a natural cause of death.

Deaths due to hypothermia are usually accidental and are the result of exposure to extreme environmental temperatures. Often these individuals are intoxicated, elderly, or exposed to severe cold temperatures. We report the case of a blind, nonambulatory, elderly man who was found alive in his home in an unresponsive state. Core body temperature at hospital was 24 degrees C (75 degrees F). At autopsy, punctate hemorrhages were present in the stomach mucosa. A 4- x 7-cm pituitary adenoma extended from a dilated sella turcica, obliterated the optic chiasm, and compressed the base of the brain in the region of the hypothalamus. Compression in this region of the brain would disrupt the temperature regulatory function of the hypothalamus and create an individual who would be susceptible to minor fluctuations in ambient temperature. The manner of death was designated as natural. This is an unusual presentation of a pituitary adenoma in the current era of advanced imaging techniques in which microadenomas are often detected and treated.

Dyke award. Influence of fiber tracts on the CT appearance of cerebral edema: anatomic-pathologic correlation.

Four monkeys received cold-induced lesions provoking cerebral edema. The edema-Evans blue complex was shown in these animals to migrate along known short and long association bundles. Computed tomographic findings in 12 human cases are discussed and correlated; all exhibit unencapsulated fluid (edema, blood, or tumor) to track along the association pathways. Major fiber bundles are separated into those that permit the spread of edema and those that seem to be resistant. The radiologic and diagnostic significance of the association bundles is discussed and their connections are reviewed.

Extracranial carotid artery arteriosclerosis. Diagnosis with continuous-wave Doppler and real-time ultrasound studies.

To determine the predictive accuracy of Doppler and real-time ultrasound studies, continuous-wave Doppler (CWD) and B-mode real-time ultrasound (RTU) studies of the carotid bifurcation were compared in 50 consecutive patients before cervicocranial arteriography. Four categories of CWD results were formed according to the severity of stenosis. Except for mild to moderate stenosis, there was a high degree of agreement (87.5% to 98.1%) between CWD results and arteriographic diagnosis. Of the arteries classified as normal on RTU study, 95.5% were arteriographically normal; of those classified as abnormal, 94.9% were abnormal on arteriography. In 94.7% of the cases in which RTU demonstrated a possible ulcer, the diagnosis was confirmed by arteriography.

Thrombosed aneurysm of the vein of Galen.

Computed tomography in a 3 1/2-year-old boy with ataxia, lethargy, fever, vomiting, and increasing irritability revealed moderate hydrocephalus and a blood density mass lesion lying superior and posterior to the 3rd ventricle. On several of the sections, the blood density was greater in the dependent than in the superior portion of the mass. The average attenuation number within the mass was 40 EMI units. The infusion of contrast agent demonstrated capsular enhancement (a target sign), which was also demonstrated by angiography. The diagnosis, which was confirmed at operation, was thrombosis of an aneurysm of the vein of Galen. The massive thrombus was resected, but the aneurysm was not excised. The patient's recovery was uneventful.

The nuclei of the vestibular nerve of the red kangaroo, Megaleia rufus.

The preceeding account describes vestibular nuclei of the kangaroo which conform to the general mammalian pattern. Certain pecularities such as subdivisions of the medial vestibular nuclei are reported but cannot be assigned functional importance. The four major vestibular nuclei and the cerebellum receive vestibular root fibers in like manner as in other mammalian brains. The nuclear patterns and the secondary connections of the vestibular complex in the kangaroo are likewise consistent with those described in other mammals. This is so evident from the description of these regions in the kangaroo and the reports in the literature that the statement needs no further documentation. However, there are certain differences which are significant. Unusual size and/or differentiation of a center, together with an increase in the projection path arising from it, is often reflected in the behavioral patterns of the animal. Thus the lateral vestibular nucleus and the ventrolateral vestibulospinal tract are conspicuously large in the kangaroo in which the methods of locomotion and the manner in which he fights must require frequent orientation in space. It is obvious that the locomotion capabilities of the kangaroo are in large measure due to his well developed vestibular complex and its descending connection. Studies of the sort represented here, then, emphasize the specializations in certain systems and provide information with regard to the interrelations between the anatomic patterns and functional specilization in these systems. They also supplement our knowledge of the course of differentiation within the mammalian phylum. It is to be noticed that specialization at a given level may occur at any place in the evolutionary scale but cephalization is an indication of a relatively progressive development from lower to higher forms.