Cutaneous seeding of renal carcinoma by Chiba needle aspiration biopsy. Case report

Fine needle aspiration biopsy yields a high rate of positive tissue with negligible local sequelae. We report the first instance known to us of Chiba needle tract seeding following this biopsy technique in a patient with renal malignancy.

Primary mediastinal embryonal cell carcinoma

It is now widely accepted that germinal cell tumors can arise primarily in the mediastinum. Primary extragenital seminoma has been documented arising in the mediastinum but very few reports are available about primary mediastinal embryonal cell carcinoma. We report a case of this rare condition with radiological and CT features.

Calcified hypernephroma. A case report

Pattern of classification in an renal neoplasm is variable. If calcium is located nonperipherally (within the mass) it is more likely to be a renal cell carcinoma. But peripheral calcification does not rule out malignancy.

Purification and properties of acyl/alkyl dihydroxyacetone-phosphate reductase from guinea pig liver peroxisomes

The peroxisomal acyl/alkyl dihydroxyacetone-phosphate reductase (EC 1.1.1.101) was solubilized and purified 5500-fold from guinea pig liver. The enzyme could be solubilized by detergents only at high ionic strengths in presence of the cosubstrate NADPH. Peroxisomes, isolated from liver by a Nycodenz step density gradient centrifugation, were first treated with 0.2% Triton X-100 to remove the soluble and a large fraction of the membrane-bound proteins. The enzyme was solubilized from the resulting residue by 0.05% Triton X-100, 1 M KCl, 0.3 mM NADPH, and 2 mM dithiothreitol in Tris-HCl buffer (10 mM) at pH 7.5. The enzyme was further purified after precipitating it by dialyzing out the KCl and then resolubilized with 0.8% octyl glucoside in 1 M KCl (plus NADPH and dithiothreitol). The second solubilized enzyme was purified to homogeneity (370-fold from peroxisomes) by gel filtration in a Sepharose CL-6B column followed by affinity chromatography on an NADPH-agarose gel matrix. NADPH-agarose was prepared by reacting periodate-oxidized NADP+ to adipic acid dihydrazide-agarose and then reducing the immobilized NADP+ with NaBH4. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified enzyme showed a single homogeneous band with an apparent molecular weight of 60,000. The molecular weight of the native enzyme was estimated to be 75,000 by size exclusion chromatography. Amino acid analysis of the purified protein showed that hydrophobic amino acid comprised 27% of the molecule. The Km value of the purified enzyme for hexadecyldihydroxyacetone phosphate (DHAP) was 21 microM, and the Vmax value in the presence of 0.07 mM NADPH was 67 mumol/min/mg. The turnover number (Kcat), after correcting for the isotope effect of the cosubstrate NADP3H, was calculated to be 6,000 mol/min/mol of enzyme, assuming the enzyme has a molecular weight of 60,000. The purified enzyme also used palmitoyldihydroxyactone phosphate as a substrate (Km = 15.4 microM, and Vmax = 75 mumol/min/mg). Palmitoyl-DHAP competitively inhibited the reduction of hexadecyl-DHAP, indicating that the same enzyme catalyzes the reduction of both acyl-DHAP and alkyl-DHAP. NADH can substitute for NADPH, but the Km of the enzyme for NADH (1.7 mM) is much higher than that for NADPH (20 microM). The purified enzyme is competitively (against NADPH) inhibited by NADP+ and palmitoyl-CoA. The enzyme is stable on storage at 4 degrees C in the presence of NADPH and dithiothreitol.

Carboxylic ester hydrolase activity in hairless and athymic nude mouse skin

The carboxylic ester hydrolase activity was compared in athymic nude mouse skin and hairless mouse skin with respect to hydrolytic ability, heat inactivation, pH optima, and substrate specificity. Five aliphatic 5'-esters of 5-iodo-2'-deoxyuridine (IDU) were incubated with skin homogenate preparations, and the effect of linear chain length and branching of the ester substituent on hydrolysis rate was evaluated. The ester hydrolase activity was three times higher in athymic mouse skin relative to hairless variety. In both mice skin preparations maximum hydrolysis rates were obtained with the valeryl ester followed by butryl, isobutyryl, propionyl and pivaloyl derivatives. Kinetic studies, however, revealed that higher ester hydrolase activity (Vmax) in athymic mouse skin is also associated with higher Km values, while the carboxylic ester hydrolases from these two different strains of mice have similar biochemical properties with respect to heat inactivation and pH optima. Athymic mouse skin resembled hairless mice skin in terms of cholinesterase content. A significant fraction (70-80%) of ester hydrolyzing activities in both strains of mice skin resulted from cholinesterases (true and/or pseudo). The remaining activity was attributed to different ester cleaving enzymes in the two strains of mice. Carbonic anhydrases and arylesterases contributed to the ester hydrolyzing activity of the athymic and normal hairless mice skins, respectively. Product inhibition by the regenerated hydrolytic product, free IDU, was also noticed which resulted in incomplete conversion of rapidly hydrolyzable 5'-esters such as the valeryl and butyryl derivatives.

Clinical course of endomyocardial fibrosis

The survival pattern, morbidity, and clinical course of 145 patients with endomyocardial fibrosis who were followed up between November 1975 and June 1987 were studied. The diagnosis was confirmed in all cases by cardiac angiography, or echocardiography, or necropsy. Percentage survival at the end of one and 9.5 years was 76.11 and 26.35 respectively. History, physical examination, electrocardiography, and cardiac catheterisation were studied at the first presentation. The determinants of early mortality were studied by univariate Kaplan-Meier estimates compared by the log rank test and Cox proportional hazards multiple regression analysis. Significant univariate predictors of early mortality were QRS axis above +90 degrees, intraventricular conduction delay (QRS duration greater than 0.12 s), duration of symptoms before presentation, New York Heart Association functional classes III and IV, presence of embolic episodes, right atrial mean pressures greater than 20 mm Hg, right ventricular end diastolic pressure greater than 20 mm Hg, and aortic oxygen saturation less than 85%. The significant multivariate predictors of mortality were cyanosis, New York Heart Association functional class at first presentation, and right atrial mean pressure greater than 20 mm Hg. The bleak prognosis of endomyocardial fibrosis did not substantially improve despite advances in the medical management of congestive cardiac failure during the period of the study.

Preparation and characterization of methotrexate-immunoglobulin conjugates

In the targeting of chemotherapeutic agents to specific cells via covalent conjugation of the agent to monoclonal antibodies, conjugation methods which lead to maximum binding capacity with minimum loss of activity (for both drug and antibody) are essential. A model system for evaluation of various conjugation procedures is described. Rabbit anti-bovine serum albumin immunoglobulin (IgG) was used to represent the antibody, and methotrexate (MTX) was used as the targeting agent. The procedures evaluated were coupling via water soluble 1-ethyl-3 (3'-dimethylaminopropyl) carbodiimide (EDCI), or via prior activation of MTX's carboxyl groups involving active ester (N-hydroxysuccinimide) or mixed anhydride (isobutylchloroformate) formation. The formation of covalent conjugates in all three cases was verified by (a) the lack of incorporation of MTX into IgG when the reactions were performed in the absence of EDCI, or when MTX was reacted without prior activation, and (b) the presence of a constant amount of MTX in the conjugates after exhaustive dialysis of gel-filtration through Sephadex G-50. High incorporation of MTX and high retention of antifolate activity resulted from the EDCI coupling reaction, but there was very low recovery of protein (conjugate) and antibody activity. The biological and physicochemical properties of the conjugates prepared by the two pre-activation methods did not show any significant difference, but the conjugates prepared by the active ester method had a longer shelf-life. Therefore, of the three reactions investigated, the active ester method is our method of choice for conjugating MTX to IgG.

A rapid method for the isolation of peroxisomes from rat liver

A preparative method for the isolation of peroxisomes from the liver of normal, untreated rats is described. The peroxisome-enriched "light mitochondrial" fraction is layered on a 30% Nycodenz (5-[N-2,3-dihydroxypropylacetamido]-2,4,6-triiodo-N,N'-bis[2, 3-dihydroxypropyl]isophthalamide) solution containing 1 mM tetrasodium EDTA and then centrifuged in an angular rotor for 1 h at 130,000gavg. Peroxisomes are sedimented to the bottom leaving other organelles at the top of the tube. On the basis of morphological and biochemical studies, it is found that the peroxisomes (marker-enzymes catalase and urate oxidase) obtained in this method are not contaminated with lysosomes (marker-enzyme acid phosphatase) and contained very few mitochondria (marker-enzyme succinate-cytochrome c reductase) and microsomal vesicles (marker-enzyme glucose-6-phosphatase).

Subcellular distribution and properties of acyl/alkyl dihydroxyacetone phosphate reductase in rodent livers

On subcellular fractionation, the enzyme acyl/alkyl dihydroxyacetone phosphate (DHAP) reductase (EC 1.1.1.101) in guinea pig and rat liver was found to be present in both the light mitochondrial (L) and microsomal fractions. By using metrizamide density gradient centrifugation, it was shown that the alkyl DHAP reductase activity in the "L" fraction is localized mainly in peroxisomes. From the distribution of the marker enzymes it was calculated that about two-thirds of the liver reductase activity is in the peroxisomes and the rest in the microsomes. The properties of this enzyme in peroxisomes and microsomes are similar with respect to heat inactivation, pH optima, sensitivity to trypsin, and inhibition by NADP+ and acyl CoA. The enzyme activity in the peroxisomes and microsomes from mouse liver is increased to the same extent by chronically feeding the animals clofibrate, a hypolipidemic drug. The kinetic properties of this enzyme in these two different organelles are also similar. From these results it is concluded that the same enzyme is present in two different subcellular compartments of liver.