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Biomedical subjects

A E Meijer

Publications and source records attributed to A E Meijer.

At least 37 records · Page 2Linked to original sources
PubMed1989

[Histochemical changes in skeletal muscles of racehorses susceptible to rhabdomyolysis after exertion. I. Early myopathological changes].

In this communication, the results of an enzyme histochemical study on m. gluteus medius of horses, sensitive to exertional myopathy, during attacks of rhabdomyolysis are presented. The activity and location of about 25 enzymes were examined. In the present report, the early metabolic changes are discussed. Within 6 min after an attack, some large rounded fibres (approximately 2%) were seen, which showed an intense red staining in the haematoxylin and eosin sections. These hypercontracted fibres showed an increase in activity of mitochondrial adenosine triphosphatase, indicating the presence of uncoupling and/or loose coupling of the mitochondria. This finding may point to a deficient production of ATP in the m. gluteus medius of horses sensitive for exertional myopathy and this deficiency may lead to pathological alterations in the skeletal muscles. The pathological fibres revealed a changed activity of other mitochondrial enzymes as well.

Animals↗
PubMed1989

[Histochemical changes in skeletal muscles of racehorses susceptible to rhabdomyolysis after exertion. II. Later myopathological and regeneration phenomena].

Needle biopsies from m. gluteus medius of 22 horses which had suffered from repeated attacks of exertional myopathy were studied at various times after an attack, to determine if metabolic alterations can be demonstrated by enzyme histochemistry. Morphological changes and activity of 25 enzymes were studied. Immediately after onset of an attack, some large rounded fibres with a defect of the oxidative phosphorylation were seen. After some hours these fibres lost their glycolytic enzyme activity, followed by disappearance of mitochondrial enzyme activity with accumulation of Ca2+-containing substances. After 16 h inflammatory cells were found in and around necrotic fibres with a strong activity of acid phosphatase and of the 2 oxidative enzymes of the pentose phosphate pathway. The 4th d after onset of the myopathy regenerating fibres could be observed with a strong activity of both NADPH-producing enzymes of the pentose phosphate pathway. The activity of the decarboxylating enzymes NADP+-malate dehydrogenase and NADP+-isocitrate dehydrogenase was increased in these fibres as well. After some month the studied skeletal muscles were completely normal again. Metabolic interpretations based on the histochemical findings are discussed and compared with those given in literature.

Animals↗
PubMed1988

Histochemical technique for the demonstration of pyruvate kinase activity.

We describe an enzyme histochemical multistep technique for the demonstration of pyruvate kinase activity. In this technique, a semipermeable membrane is interposed between the incubation medium and the tissue sections, thus preventing diffusion of the enzyme into the medium during the incubation period. In this histochemical system, phosphoenolpyruvate (PEP) donates its phosphate group to ADP in a reaction catalysed by pyruvate kinase. Next, exogenous and endogenous hexokinase catalyses the reaction between ATP and D-glucose to yield D-glucose-6-phosphate and ADP. The D-glucose-6-phosphate is oxidized by exogenous and endogenous D-glucose-6-phosphate dehydrogenase, and concomitantly, the generated electrons are transported via NADP+, phenazine methosulphate and menadione to nitro-BT, which is finally precipitated as formazan. Sodium azide and amytal are included to block electron transfer to cytochromes. The method proved to be of value for the qualitative demonstration of pyruvate kinase activity in tissue sections of kidneys, heart muscle and skeletal muscle. For quantitative studies and for investigating the activity of this enzyme in liver sections, the method cannot be recommended.

Adenosine Diphosphate↗
PubMed1988

Histochemical features of tubular aggregates in diseased human skeletal muscle fibres.

This communication presents the results obtained in tubular aggregates of 24 enzyme histochemical techniques for demonstrating activity of oxidoreductases, transferases, hydrolases and isomerases. The activity characteristics of the tubular aggregates in m. gluteus medius of 18 patients with diseases of the neuromuscular system were almost identical. A high activity of the mitochondrial enzymes, NADPH: tetrazolium oxidoreductase, NADH:tetrazolium oxidoreductase and cytochrome c oxidase, could be shown in the pathological structures, whereas the activity of the mitochondrial enzymes, glycerol-3-phosphate:menadione oxidoreductase, succinate:PMS oxidoreductase, malate:NAD+ oxidoreductase and isocitrate:NAD+ oxidoreductase, and the partial mitochondrial enzymes, malate:NADP+ oxidoreductase and isocitrate:NADP+ oxidoreductase, was very slight or even absent. There was a moderate to strong activity of the glycolytic enzymes lactate:NAD+ oxidoreductase, glyceraldehyde-3-phosphate:NAD+ oxidoreductase, phosphofructokinase, phosphoglucomutase and glucose phosphate isomerase. In contrast, the activity of alpha-glucan phosphorylase was slight. The activity of phosphogluconate:NADP+ oxidoreductase, glucose-6-phosphate:NADP+ oxidoreductase and 5'-nucleotidase was slight, whereas there was no activity of myosin ATPase and mitochondrial ATPase, acid phosphatase or alkaline phosphatase. The high activity of AMP-deaminase was very striking. The activity of peroxidase was moderate. Results obtained with adsorption studies point to adsorption of some of the enzymes studied to the tubular aggregates in vivo and this phenomenon very probably determined the histochemical characteristics of these structures.

Histocytochemistry↗
PubMed1988

Enzyme histochemistry on muscle biopsies as an aid in the diagnosis of diseases of the equine neuromuscular system: a study of six cases.

Muscle biopsies from six horses with clinical histories of muscle atrophy, muscle tremors, myopathic symptoms, unsteadiness of pelvic limbs and progressive ataxia were examined. Muscle biopsies were studied with enzyme histochemical techniques to evaluate the diagnostic values of these methods in cases suspected of suffering from neuromuscular disorders. Hypertrophy, atrophy, fibre splitting, waxy degeneration, phagocytosis and necrosis were seen in haematoxylin eosin stained sections of the different cases. Fibre type predominance and fibre type grouping were seen in the calcium ion stimulated myosine ATP-ase (Ca-ATP-ase) stained sections of some cases. 'Moth-eaten fibres' were demonstrated in three cases by staining with NADH: nitro blue tetrazolium oxidoreductase (NADH-TR), succinate dehydrogenase (SDH), NADH dependent malate dehydrogenase, cytochrome c oxidase and by lactate dehydrogenase. The catabolic enzymes, acid phosphatase (ACP) and 5'-nucleotidase were active in cases with fibre phagocytosis. The oxidative part of the pentose phosphate pathway in myopathic tissue seemed to be important in three cases, demonstrated by the increased activity of glucose-6-phosphate dehydrogenase (GPDH) and 6-phosphogluconate dehydrogenase (PGDH). The important feature of diseased horse muscle was that the pathohistochemical changes were exactly the same as in diseased skeletal muscles of humans. The application of tissue saving enzyme histochemical techniques can be recommended in the study of muscle tissue from horses suffering from suspected neuromuscular disorders.

Animals↗
PubMed1985

The histochemical demonstration of fructose diphosphate aldolase activity using a semipermeable membrane technique.

In this communication an enzyme histochemical multistep technique for the demonstration of class 1 fructose-1,6-diphosphate aldolase in heart and skeletal muscle sections is described. With this technique a semipermeable membrane is interposed between the incubating solution and the tissue sections preventing diffusion of the enzyme into the medium during incubation. In the histochemical system the enzyme cleaves the substrate D-fructose-1,6-diphosphate to dihydroxyacetone phosphate and D-glyceraldehyde-3-phosphate. The dihydroxyacetone phosphate is reversibly converted into D-glyceraldehyde-3-phosphate by exogenous and endogenous triose phosphate isomerase. Next the D-glyceraldehyde-3-phosphate is oxidized by exogenous and endogenous glyceraldehyde-3-phosphate dehydrogenase and the electrons are transported concomitantly via NAD+, phenazine methosulphate and menadione to nitro-BT. Sodium azide and amytal are incorporated to block electron transfer to the cytochromes.

Animals↗
PubMed1985

An enzyme histochemical study of human sinus node, coronary sinus, and mitral valve muscle.

An enzyme histochemical study of the sinoatrial node, the coronary sinus, and the atrial muscle extending into the anterior mitral valve was performed on human hearts. Investigation of the activity and localization of the structurally bound enzymes was performed by conventional histochemical techniques. Determination of the activity of nonstructurally or weakly structurally bound enzymes was performed by histochemical techniques in which leakage of enzymes during the incubation period was reduced by the application of semipermeable membranes. The sinoatrial node is characterized by a high degree of anaerobic enzyme capacity and a relatively low degree of aerobic enzyme capacity. The discriminatory nature of these reactions allows examination of the structure of the sinoatrial node and its approaches. The presence of transitional cells was confirmed; isolated clusters of nodal cells were found in the atrial myocardium around the sinoatrial node, but no evidence of specialized tissue forming the beginning of an internodal pathway was found by this technique. The specific histochemical reactions that characterize the sinoatrial node also occur in the atrial muscle, extending into the anterior mitral valve, the anterior wall of the coronary sinus, and the atrial tissue near the orifice of the coronary sinus. These observations seem to corroborate the hypothesis that arrhythmic ectopic foci can arise in these regions.

Acetylcholinesterase↗
PubMed1985

Variation of fiber types in the triceps brachii, longissimus dorsi, gluteus medius, and biceps femoris of horses.

The distribution of type-I and type-II fibers in 9 different parts of the musculi triceps brachii, longissimus dorsi, gluteus medius, and biceps femoris was studied to determine whether biopsies from these muscles give reliable information. All 4 investigated muscles were not homogeneous in their fiber-type distribution. Large differences existed among different muscle parts. The percentage of type-I fibers increased toward the deeper and cranial parts of the muscles. In the same zone of the gluteus muscle, differences of 30% were found for type-I fibers. Therefore, results obtained by biopsies of muscles must be interpreted with caution.

Animals↗
PubMed1985

Enzyme histochemical features of equine gluteus muscle fibers.

Gluteal muscle specimens were taken from 4 horses. From 1 of the 4 gluteal muscles, serial sections were prepared. Individual muscle fibers were identified and studied, using photomicrographs of sections stained by different enzyme histochemical methods. In specimens in which cytoplasmic soluble enzymes were studied, use was made of the semi-permeable membrane technique to hamper enzyme diffusion into reaction fluids. Enzymes involved in glycogenolysis, glycolysis, the tricarboxylic acid cycle, synthesis of reduced nicotinamide adenine dinucleotide phosphate, the pentose phosphate cycle, the alpha-glycerolphosphate shuttle, the respiratory chain, catabolism, and muscular contraction were studied. Some key enzymes of different metabolic pathways were also included. Each of 3 fiber types identified had distinct features. Type I fibers were characterized by a relatively strong aerobic capacity, compared with type IIA fibers, which were more glycolytic and had strong aerobic and moderate-to-strong anaerobic capacity. Type IIB fibers were characterized by a relatively low aerobic and a relatively high anaerobic capacity, and were glycolytic. Activities of phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and alpha-naphtylesterase (nonspecific esterase) were so markedly different in the 3 fiber types that fiber typing was possible, aided by the demonstration of the activities of these enzymes. In type IIB fibers, the pentose phosphate cycle was more important than in the other fiber types. Except for the unexplained high alpha-naphtylesterase activity in type IIB fibers, catabolic enzymes were not active in healthy equine muscle fibers.

Animals↗
PubMed1984

Diazonium inactivation in simultaneous-coupling and product inhibition in post-coupling azo-techniques for demonstrating activity of acid hydrolases.

In this communication results are presented of an investigation in which the activity of the hydrolytic enzymes acid phosphatase, beta-glucuronidase, non specific arylesterase, microsomal arylsulphatase, beta-galactosidase, beta-N-acetylglucosaminidase, acid alpha-glucosidase and aminopeptidase M are demonstrated in tissue sections with simultaneous- and post-coupling azo-techniques. Semipermeable membrane techniques are used to hamper enzyme diffusion during the incubation period. From the histochemical and biochemical findings it appeared that an advantage of the post-coupling techniques over the simultaneous-coupling techniques is that inactivation of the enzymes by the coupling reagents is avoided. On the other hand post-coupling techniques are subject to product inhibition. With kinetic inhibition studies it is found that for microsomal arylsulphatase and non-specific arylesterase this product inhibition is non-competitive. This product inhibition may be a problem for histochemical quantitative post-coupling techniques for the determination of acid hydrolase activity.

Animals↗
PubMed1984

The inhibitory effect of actinomycin D and cycloheximide on the increase in activity of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in experimentally induced diseased skeletal muscles.

The myotoxic effect of the subcutaneous administration of N,N1-dimethyl-p-phenylenediamine (DPPD) in rats was enhanced by the simultaneous administration of hyaluronidase. The resulting myopathy was associated with an early and dramatic increase in activity of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Administration of actinomycin D or cycloheximide prior to the combined DPPD and hyaluronidase treatment prevented the increase in activity of both pentose phosphate pathway enzymes, indicating that the increase in activity requires RNA synthesis and protein synthesis. The possibility that the increase in activity of both NADPH-regenerating enzymes results from the modification by effectors of existing less active forms of these enzymes leading to more highly active forms was refuted.

Animals↗
PubMed1984

Deposition of bauxite dust and pulmonary fibrosis.

In a 70 years old worker in the bauxite industry in Surinam, who died of myocardial infarction, bauxite deposits were found in the lung in areas of mild pulmonary fibrosis. The identification and the localization within these areas of the bauxite deposits was determined by a histochemical mineralization technique and by scanning electron microscopy and electron microprobe analysis. The possible relationship between the presence of bauxite in the lung tissue and the pulmonary fibrosis is discussed.

Aged↗
PubMed1983

Fluctuations in the enzymatic activity of the human endometrium.

Cyclic fluctuations were studied in the activity of oxidoreductases playing a role in the major energy metabolic pathways, lysosomal and non-lysosomal hydrolases and some non-enzymatic cytochemical components demonstrable in different developmental physiological or pathophysiological phases of human endometrium. The total scope of the study involved 170 tissues and cytological specimens. The cytological material included microcurettings, aspirates, brush preparations and tissue prints. An evaluation of the usefulness of the application of enzyme cytochemistry to cytological material is included. The most important results were a cyclic fluctuation and a progestagenic controlled increase in the activity of many oxidoreductases, especially the NADPH regenerating enzymes of the pentose phosphate pathway, and of the NADP+ dependent isocitrate dehydrogenase. The histochemical evaluation of the activity of these NADP+ linked enzymes can therefore be recommended for the evaluation of the physiological status of the endometrial cells, especially in patients with infertility problems.

Acid Phosphatase↗
PubMed1983

Follow-up study of a myopathy with loosely coupled mitochondria.

This communication deals with a clinical, histological, histochemical and biochemical follow-up study of a boy with an ameliorating myopathy with loosely coupled mitochondria who was studied earlier. In the course of about 15 years the clinical condition of the patient improved greatly. In a biopsy of skeletal muscle the same pathological features were found as before, but the pathological changes were much less severe. In contrast to earlier findings, the majority of the fibres with a loosely coupled state of the mitochondria belonged to the anaerobic type II fibres.

Adenosine Triphosphatases↗
PubMed1983

Motor activity and muscle properties in the hemidecerebellate cat.

Luciani's ipsilaterally acting 'trophic' cerebellar influence on striated muscle was reinvestigated in hemidecerebellate preparations of varying extent. Cats with hindlimb postural asymmetries for 4 or more days after the lesion developed a bilateral reduction of maximum tetanic tension and increased twitch/tetanus ratios of soleus. In addition, soleus on the side of the lesion lost force and weight, showed decreased twitch contraction and half-relaxation times, elevated myosin ATPase activity in part of its fibres, occasional fibre necrosis and a few snake coils. Protracted postural asymmetry occurred only if complete hemicerebellectomy included ablation of the lateral vestibular nucleus and extended for at least 3.0 mm across the midline into the contralateral vermal and intermediate cortex, especially of Larsell's lobuli IV and V. Most simply, the cerebellar effect on muscle is explained as the result of altered motoneuronal activation patterns. Comparison of the experimental soleus changes with Holmes's clinical findings in cases of cerebellar injury suggests that muscle itself participates in experimental and human cerebellar asthenia.

Adenosine Triphosphatases↗