Effects of iron and ascorbic acid on acid phosphatases of the enamel organ of rat molars

Protein extracts from 6- to 11-day-old rat enamel organs were applied to columns of carboxymethyl-52 cellulose. Protein eluted from the columns was assayed for acid phosphatase activity with substrates para-nitrophenylphosphate (p-NPP). beta-glycerolphosphate (β-GP), ATP and phosphocasein. A weakly-bound peak of activity (A) emerged first which was insensitive to stimulation by iron and ascorbic acid. This enzyme hydrolysed only the phosphomonoester substrates (p-NPP and β-GP). A strongly bound peak of activity (B) emerged later and was completely separated from the first activity. It hydrolysed all substrates except β-GP, and was stimulated at least 10-fold by 0.1 mM ferrous ion (Fe²⁺) in the presence of a strong reducing agent (l.0mM ascorbic acid). Both substances were more effective as stimulators when used together than they were when each was used separately. Dependency on these co-factors for the development of full activity increased with purification, especially when phosphocasein was substrate. The results were similar for each age of rat used. These properties of enzyme B are parallel with those of the acid phosphoprotein phosphatases of liver and spleen, and the tartrate-resistant acid phosphatase of rat bone. We conclude that enzyme B requires iron and a reducing agent for full activity and has properties that distinguishes it from the classical acid phosphatases (E.C. 3.1.3.2.).     

Retinal venous sheathing in multiple sclerosis

Multiple sclerosis is among those disease entities in which sheathing of the retinal veins has been documented. A case with marked unilateral retinal vein sheathing in a patient with a diagnosis of multiple sclerosis is reported. Discussion with reference to epidemiology, etiology, histopathology, differential diagnosis, and management is presented.     

Investigation of the effects of methyltestosterone, cortisone and spironolactone on the hepatic microsomal mixed function oxidase system in male and female rats

Acute (4 days) and chronic (4 weeks) administration of methyltestosterone, cortisone and spironolactone changes drug metabolism in hepatic microsomes of male and female rats by altering the degree of binding of drugs to the cytochrome P-450, the activity of NADPH-cytochrome c reductase, and the rate of reduction of the cytochrome P-450-drug complex. These steroids also alter the ratio of stoichiometric relationship between drug metabolism and CO-inhibitable NADPH-oxidation. This ratio is sex dependent, being approximately 1·0 in males and 0·2 in females. The effect of the three steroids on the ratio is also sex dependent. The steroids tend to increase the ratio in females and decrease it in males.     

Application of image-guided surface coil P-31 MR spectroscopy to human liver, heart, and kidney

Localized phosphorus-31 magnetic resonance (MR) spectroscopy in humans has previously been accomplished with surface coils by means of depth-resolved surface coil spectroscopy or rotating frame experiments, in which the extent of tissue sampled critically depends on surface coil placement. The authors' goal was to modify the surface coil image-selected in vivo spectroscopy (ISIS) experiment to accomplish three-dimensional volume selection through application of selective pulses in the presence of B0 gradients. Advantages of ISIS include the ability to use proton images to define the volume of interest (VOI) and reduced dependence on exact positioning of the surface coil. However, rapid replication of the surface coil ISIS experiment can cause spectral contamination from signals originating outside the VOI. A modified version of the ISIS experiment was developed to alleviate contamination under conditions of rapid replication. Applications of localized P-31 MR spectroscopy for observation of high-energy phosphorus metabolites are presented in human liver, heart, and transplanted and normal kidney.     

Effects of dantrolene on adrenal cortical function

Adverse effects of dantrolene include abnormal liver function tests, hepatic injury, and alteration of the hepatic mixed function oxidase cytochrome P-450 system. The following study conducted in rats indicates that the effective dose of dantrolene that has been shown to decrease hepatic cytochrome P-450 also causes adrenal enlargement with a marked reduction in serum glucocorticoids. The ratio of adrenal wet weight/body weight was significantly (P < 0.05) increased following 5 days of injection with a minimum dose of 25 mg dantrolene/kg body weight. The minimum effective dose of dantrolene that significantly (P < 0.05) lowered serum glucocorticoids was 50 mg/kg body weight. Serum glucocorticoids were reduced by half following 5 days of treatment with 100 mg dantrolene/kg body weight. The levels of serum glucocorticoids were 80 per cent of control serum levels and the adrenal wet weight/body weight ratio was 85 per cent of control values following 3 days of recovery after 5 days of pre-treatment with 100 mg/kg of dantrolene. It appears that dantrolene acts in a manner similar to diphenylhydantoin to reduce adrenal glucocorticoid secretion, with a possible alteration or reduction in the negative feedback response to the pituitary and resultant enlargement of the adrenals.     

Primary carcinoma of the gallbladder.

The records of patients with primary carcinoma of the gallbladder treated at Charity Hospital, New Orleans, Louisiana, from 1965 through 1978 were reviewed. Eighty patients had histologically proven primary carcinoma of the gallbladder. Sixty-nine patients had sufficient data available for evaluation. Only one patient (1.4%) was clinically free of disease at five years. Surgical procedures were performed in 45 of the 69 patients. The remainder of the patients had their disease proved at autopsy. Thirty-five patients had widespread metastatic disease at the time of operation. None of these patients survived more than one year. Only 10 patients had potentially curable lesions. The diagnosis of carcinoma of the gallbladder was not made at operation in eight of these patients. The only five-year survivor was in this subgroup. This patient had papillary adenocarcinoma confined to the mucosa and muscularis, and had a cholecystectomy alone. This report reinforces the difficulty in diagnosis and the dismal prognosis for patients with primary carcinoma of the gallbladder. Intraoperative examination of the gallbladder, earlier operation for documented gallbladder disease, and more aggressive surgical therapy should improve survival figures.