An analysis of the impact of the loss of a primary care physician on a patient population

The authors describe two cases of giant middle cerebral artery aneurysms presenting as mass lesions. Angiograms in each case revealed a distinctive serpentine vascular channel surrounded by an avascular area causing a "mass effect." Both lesions were resected in toto with excellent clinical results. Similar lesions in the literature are noted and the pathophysiology and origin of this group of aneurysms are discussed.     

Nephrectomy: indications and complications in 347 patients

The indications, complications and mortality rate in a recent 12-year experience with 347 nephrectomies were reviewed. Renal tumor is the most frequent condition requiring nephrectomy, probably because of the improved, non-ablative methods to treat inflammatory, obstructive, calculous and hypertensive renal disease. The over-all mortality rate was 1.4 per cent but was almost nil in the absence of malignancy.     

Postural changes in plasma renin activity and responses to vasoactive drugs in a case of Shy-Drager syndrome

A male aged 47 years with gross autonomic insufficiency as part of the Shy-Drager syndrome is described. He did not sweat normally when warmed, and his circulatory responses to mental arithmetic, the Valsalva manoeuvre, and head-up tilt were abnormal indicating severe sympathetic failure. During head-up tilt there was a rise in plasma renin activity and plasma aldosterone. It is argued that plasma renin activity is not dependent on sympathetic nervous activity and may be mediated by renal baroreceptors. These rises may help sustain the blood pressure in such patients during repeated head-up tilts. Infusions of L-noradrenaline and angiotension produced greater hypertension, and injections of isoprenaline greater hypotension than in controls. Although it is difficult to exclude the possibility that one factor in this may be hypersensitivity of receptors in blood vessel walls, the principal factor is likely to be the absence of those baroreflexes of which the efferent pathways are in the sympathetic nervous system.     

Dermatophilus dermatitis enzootic in deer in New York State and vicinity

Bis-(4-methyl-1-homopiperazinylthiocarbonyl)-disulphide (FLA-63) inhibits in vitro purified bovine adrenal medullary dopamine beta-hydroxylase (BDH) concentration-dependently; 50% inhibition is produced by 2 x 10(-6)M FLA-63. Spectrophotometric experiments show that FLA-63 is reduced by ascorbate very likely to the corresponding dithiocarbamate-derivative, which acts as a Cu++-chelator. Cu++-ions are able to completely abolish the inhibition of the DBH caused by FLA-63 in concentrations up to 2.5 x 10(-6)M. It is concluded that FLA-63 inhibits the DBH mainly in its reduced form via the formation of a chelate-complex with copper ions derived from the DBH.