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Biomedical subjects

M A Khan

Publications and source records attributed to M A Khan.

At least 19 recordsLinked to original sources
PubMed1979

A histochemical study of denervated marsupial hemidiaphragm.

The marsupial (quokka) hemidiaphragm showed postdenervation hypertrophy and subsequent atrophy. The type II muscle fibres hypertrophied up to 20 days postoperation and then regressed. However, the type I fibres hypertrophied throughout the experimental period (100 days) studied. Unlike denervated eutherian hemidiaphragm, fibre-splitting was absent in the denervated marsupial muscle. An enhancement of the ATPase reaction in the denervated type I fibres may be due to dedifferentiation. Presumably innervation exerts a 'negative control' and prevents increase of type I fibre size in the normal hemidiaphragm.

Adenosine Triphosphatases↗
PubMed1979

A histoenzymatic study of rat intrafusal muscle fibres.

The histochemical activities of myofibrillar adenosine triphosphatase (ATPase), succinic dehydrogenase (SDH) and alpha glycerophosphate dehydrogenase (alpha-GPD) were studied in intrafusal muscle fibres of rat fast and slow muscles. The ATPase reaction was carried out after the three standard acid preincubations. The cold K2-EDTA preincubated ATPase reaction product was similar to that seen following the regular or alkali-preincubated ATPase reaction, except that the intermediate bag fibres exhibited much higher activity after cold K2-EDTA preincubation. Following either acetic acid solution or cold and room temperature K2-EDTA-preincubation, followed by the ATPase reaction, chain fibres of the fast muscles vastus lateralis and extensor digitorum longus exhibited a very low amount of reaction product as compared with those of the slow soleus. Veronal acetate and K2-EDTA preincubations (and equally preincubation in acetic acid solution) resulted in acid stable ATPase activity along the entire length of the typical bag fibres but only in the polar regions of the intermediate bag fibres. On the basis of differing alpha-GPD reaction, two sub populations of nuclear chain fibres were discovered in one spindle. It is a matter of conjecture, to what extent the histochemical differences of intrafusal fibres from fast and slow muscles reflects functional distinctions in the response to stretch of muscle spindles from fast and slow muscles.

Adenosine Triphosphatases↗
PubMed1979

Histochemical and ultrastructural characteristics of a new muscle fibre type in avian striated muscle.

The serratus metapatagialis (SMP) muscle of the pigeon has been studied histochemically and ultrastructurally. At the gross anatomical level the SMP is clearly divisible into a peripheral whitish band and a red portion comprised predominantly of 'pale' and 'red' fibres respectively. The pale fibres possess low succinate dehydrogenase, low mitochondrial content, absence of subsarcolemmal mitochondrial aggregates, low fat, moderate glycogen, high phosphorylase, low-to-moderate regular myofibrillar adenosine triphosphatase (M-ATPase), activation of M-ATPase following acid preincubation and jagged Z bands. On the basis of these characteristics, these physiologically slow muscle fibres have been termed 'Type I white or slow-twitch glycolytic'. The SMP red fibres, however, possess high aerobic as well as glycolytic capacity, high M-ATPase activity which is labile after acid preincubation and thick but straight Z bands; therefore, they are the 'Type II red or fast-twitch oxidative-glycolytic'.

Adenosine Triphosphatases↗
PubMed1979

On the heterogeneity of capillaries of pigeon pectoralis muscle: a histoenzymatic and ultrastructural study.

Earlier studies had failed to show the presence of capillaries between the white fibres of pigeon pectoralis muscle. In this paper, data are reported for the first time documenting that these capillaries occur in both intra- and inter-fasicular areas of the muscle. Fresh frozen sections of pigeon pectoralis major muscle were incubated for alkaline ATPase reaction following pretreatment with different EDTA solutions (4.3 mM, pH 4.3). The results showed the existence of an inherent heterogeneity of capillaries. The capillaries of white fibres stained intensely for K+/Mg2+-EDTA or Mg2+-EDTA pre-incubated ATPase; the capillaries of red fibres stained poorly. Both white fibre and red fibre capillaries were examined ultrastructurally in the non-perfused pigeon pectoralis muscle. It is suggested that a possible correlation exists between the distinctive metabolic and mechanical characteristics of the Type II white, glycolytic, fast-twitch fast-fatigue muscle fibres and the high ATPase activity of their capillaries.

Adenosine Triphosphatases↗
PubMed1979

Development of the squamosomandibular articulation in the Mongolian gerbil (Meriones unguiculatus). II. Succinate dehydrogenase activity.

Succinate dehydrogenase activity has been studied, according to the method of Nachlas et al. (1957), in the developing tissues forming the squamosomandibular articulation in the Mongolian gerbil from its inception through the sixty postnatal day. Increased activity was observed in the chondroblasts, osteoblasts and mesenchymal tissues of the developing articulation. The chondroclasts of the developing mandibular condyle displayed intense reaction as did the osteoclasts of the developing bony articulation. Succinate dehydrogenase activity appeared to be related to the functional maturity of the cellular elements of the developing joint.

Animals↗
PubMed1979

Absorption and elimination of 14C-cis-chlordane and 14C-photo-cis-chlordane by goldfish Caraccius auratus.

Photo-cis-chlordane is accumulated by goldfish to a greater extent than cis-chlordane during a 16-hr exposure to 5 parts per billion (ppb) of each insecticide. However, the concentration of photo-cis-chlordane in vital organs (brain, nervous system, heart, liver, kidneys) during the 1-, 2-, and 4-day exposure is less than that of cis-chlordane. Only the swim bladder shows a much higher concentration of photo-cis-chlordane than cis-chlordane. These differences could hardly account for twice the higher toxicity of the former to goldfish. The transfer of pre-exposed fish to insecticide-free water resulted in faster elimination of photo-cis-chlordane than cis-chlordane; after five weeks, about 90% of the former was eliminated as compared with only 58% of the latter. High residues of both insecticides in the bile and the intestine during the initial period of exposure indicate a biliary route of elimination.

Absorption↗
PubMed1979

On the mechanism of HBFP stain and an analysis of heterogeneous nuclei in rat hepatocytes.

Haematoxylin-Basic fuchsin-Picric acid (HBFP) technique characterises two varieties of nuclear population in the rat hepatocytes. HBFP technique is capricious and the differentiation step should be controlled stringently; ethanolic picric acid, therefore, is recommended as a differentiation fluid. On the basis of controls treated with (1) ribonuclease (RNase), (2) deoxyribonuclease (DNase), (3) Bouins fluid or (4) protease, this study has determined that DNA-associated protein(s) and some DNA may be responsible for the HBFP produced nuclear fuchsinorrhagia. The heterogeneous nuclei of the rat hepatocytes were statistically analyzed in periportal, centrilobular and intermediate areas. Fuchsinorrhagic nuclei were preponderant in the periportal areas.

Animals↗
PubMed1979

Multiple apocrine cystadenomas.

A 56-year-old man had approximately forty apocrine cystadenomas of the face and ears. Clinical examination and light microscopic findings were typical for apocrine cystadenomas. Electron microscopic findings showed an absence of annulate lamellae, thus differing from the only previously reported study. Review of the literature indicates that a large number of apocrine cystadenomas, such as on our patient, has not been reported previously.

Apocrine Glands↗
PubMed1979

Sacroiliac joint abnormalities in paraplegics.

We studied 186 paraplegic patients to clarify the pathogenesis of the sacroiliac (SI) joint abnormalities reported in these patients. Partial or complete fusion of SI joints was noted in 47 patients (25%), and milder degrees of abnormalities of these joints were present in 27 patients (15%). The abnormalities differed from those seen in ankylosing spondylitis and were found more commonly in patients with high levels of cord injury. It is likely that trunk mobility is necessary to maintain integrity of SI joint and that absence of such mobility compromises SI joint structure in many paraplegics.

Adolescent↗