Biomedical subjects

H Troyer

Publications and source records attributed to H Troyer.

6 recordsLinked to original sources

PubMed1977

Bone alkaline phosphatase kinetics studied by a new method.

Studies of enzyme kinetics by histochemical methods has been seriously impaired by available methods. This study combines two newer methods, i.e., sectioning undecalcified bone from glycol methacrylate and the use of atomic absorpton spectrophotometry for photographic densitometry. The results indicate that the substrate concentration for zero order kinetics of the alkaline phosphatase reaction in bone is 0.5 mg/ml of substrate; and the Km of the same reaction is estimated to be 0.25 mg/ml or 0.56 mM of substrate.

Alkaline Phosphatase↗

PubMed1977

Spectral characteristics of metachromatically stained cartilage: effects of enzymatic degradation and dehydration.

When a microspectrophotometer was used to study cartilage, stained metachromatically with Azure A and Safranin O, the following 3 points were made: 1. the absorption maximum of stained cartilage matrix is identical to that reported for solutions of these dyes containing chondroitin sulfate; 2. partial enzymatic degradation of the cartilage matrix has no effect on the position of the absorption peak (although the intensity is greatly diminished); 3. ethanolic dehydration shifts the absorption peak somewhat toward the orthochromatic position, and decreases the intensity of the stain.

Cartilage↗

PubMed1975

The effect of short-term immobilization on the rabbit knee joint cartilage. A histochemical study.

Rabbit knee joints were immobilized in the extended position for 1 to 6 days, and examined by means of histochemical techniques. In the articular cartilage matrix, the earliest change was the loss of affinity for metachromatic stains, confirming earlier observations. The affinity of cartilage for high iron diamine and alcian blue stains was also diminished, although less dramatically; these stains demonstrated the concentration of glycosaminoglycans more accurately than metachromatic stains. With the colloidal iron method, changes were seen in the chondrocytes before there was any loss of affinity for metachromatic stains. Following only 1 or 2 days of immobilization, the chondrocytes in the gliding surface of the joint stained intensely with colloidal iron whereas those in the controls stained very minimally.

Alcian Blue↗

PubMed1975

Atomic absorption spectrophotometry applied to photographic densitometry.

For this study of photographic densitometry, sections of cartilage stained with Alcian Blue, safranin O and high iron diamine were photographed at x40 with Nikon photomicrography equipment on Kodak Panatomic X film with appropriate filters to enhance contrast. Portions of the developed negative films were selected from intercellular matrix regions, and circles of film equivalent in diameter to a 30-mu circle of tissue were obtained with a hand-held paper punch. Silver was eluted from the circles of film with 35% nitric acid, and the quantity of silver deposited on the film was determined by atomic absorption spectrophotometry as a measure of stain intensity. The intensity determined by this analytic procedure compared favorably with results obtained previously from the same tissue with microspectrophotometry. This method of silver analysis has advantages over earlier studies which used silver elution to determine photographic densitometry in its technical ease, accuracy and sensitivity. Furthermore, this method compares well with microspectrophotometry in its results and has the advantages of relative inexpensiveness and availability of equipment.

Animals↗

PubMed1975

Enzyme histochemistry of undecalcified bone and cartilage embedded in glycol methacrylate.

Undecalcified bone and cartilage tissue blocks were fixed for 3 h in cold formol-calcium, rapidly dehydrated with a graded series of cold ethanol, and embedded in glycol methacrylate. 2 mum sections were produced with a Sorvall JB-4 microtome using glass knives. The quality of the sections were usually excellent except for hard bone from old subjects where the bone sometimes shattered while sectioning. This method is short, relatively uninvolved and eliminates en bloc decalcification. Moreover, the method is gentle enough to allow the histochemical demonstration of alkaline and acid phosphatase by the azo dye methods, and acid phosphatase, 5'-nucleotidase and ATPase by the lead precipitation methods.

Acid Phosphatase↗

PubMedDate not supplied

Histochemical investigation of adjuvant-induced arthritis.

Rats with adjuvant-induced arthritis were observed to have increased alkaline phosphatase, acid phosphatase (two isozymes), and ATPase activity in the radial zone of articular cartilage, at the osteochondral junction, and in the bone marrow elements. A qualitative and quantitative reduction azure A, PAS colloidal iron, alcian blud critical electrolyte concentration staining (0.4 and 0.9 M (mg Cl2) was also observed in corresponding areas. These findings suggest the degradation of the articular cartilage matrix with possible simultaneous or resultant calcification.

Acid Phosphatase↗