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Biomedical subjects

W G Mair

Publications and source records attributed to W G Mair.

At least 19 recordsLinked to original sources
PubMed1989

The morphological sequences in man of de- and reinnervation in free muscle transfer with microneurovascular anastomoses.

Muscle biopsies from two patients treated by free gracilis muscle transfer and micro-neurovascular anastomoses for long standing facial palsy due to previous damage to the facial nerve during removal of tumours were examined by histochemistry and electron microscopy. Sequential muscle biopsies of one case taken at various intervals after transferring the muscle permitted the study of events of de- and reinnervation of human skeletal muscle. The changes in the early stages of denervation included atrophy of type 2B fibres. This was followed by progressive atrophy of all fibre types, distortion of the internal structure of the muscle fibres with the incidence of various cytoplasmic inclusions. Massive necrosis of the muscle did not occur. A prominent increase in satellite cells and their maturation to myotubes and new muscle fibres were evident. Reinnervation occurred with the formation of neuromuscular junctions some of them being at preformed sole plates. Fibre type grouping was apparent in addition to other changes such as the occurrence of targetoid hypertrophied muscle fibres. These changes are similar to those described previously during de- and reinnervation studies in experimental animals.

Adult↗
PubMed1986

Type distribution of muscle fibres and their ultrastructure related to intracellular elemental composition as revealed by energy dispersive X-ray microanalysis. A study of multicore myopathy.

Four cases of congenital myopathy, two children and two adults, are described whose light-microscopical and ultrastructural findings are consistent with a multicore myopathy. In all cases a hereditary etiology to the disorders is obvious presumably by an autosomal recessive trait. Fibres with central nuclei and multiple minicores was a prominent finding in all cases. Energy dispersive X-ray microanalysis of single muscle fibres revealed a normal intracellular content of elements (sodium, potassium and chlorine). This is in contrast to the findings in some cases of s.c. myotubular myopathy earlier described from our group where content of sodium and chlorine is markedly increased while that of potassium is decreased. It is suggested that in myotubular myopathy membrane dysfunction causing decreased ionic gradients is an important feature of the pathophysiology while in multicore myopathy other mechanisms, as a suggestion related to mitochondrial and myofibrillar function play a more prominent part. From a diagnostic point of view it seems that X-ray microanalysis can be used to differentiate the two conditions.

Adult↗
PubMed1986

Ultrastructure of developing human muscle: the problem of multinucleation of striated muscle cells.

The authors studied by electron microscopy the muscle of 27 human foetuses ranging from 9 weeks to 9 months development. It was possible to observe that disintegration of the plasma membranes of adjacent myoblasts and myotubes which share a common basement membrane tube appears to occur in longitudinally disposed cells of those categories. This may help to explain how further nuclei may be incorporated into well developed myotubes and how the striated muscle cells become multinucleated during embryonic myogenesis and regeneration in vivo.

Basement Membrane↗
PubMed1983

Muscle changes in protein-deprived young rats. A morphometrical, histochemical and ultrastructural study.

Rats were reared on a standard diet up to the age of 6 weeks when they were divided into two groups. One was fed on a diet containing 14% protein and the other on a diet with only 1.5% protein. The size of the various fibre types of the EDL muscle of both groups was assessed at 6 and 25 weeks of age. All the fibre types of protein-deprived rats were smaller compared to the age-matched controls, the difference being most evident in the 2B fibres. In the protein-deprived rats the 2B fibres atrophied while the type 1 and type 2A fibres simply failed to grow. Histochemical and ultrastructural examination revealed a marked reduction of the subsarcolemmal mitochondria after prolonged protein deprivation; normally large accumulations of mitochondria are seen preferentially in type 2A fibres.

Animals↗
PubMed1982

Genuine myotubular myopathy.

Two patients, a father and his 14-year-old son, were suffering from a facioperoneal syndrome, and muscle biopsy findings were consistent with a myotubular myopathy. The father exhibited central nuclei in most muscle fibers, but his son had typical changes exclusively in hypotrophic type I fibers. The cytochemical and ultrastructural analysis revealed a spectrum of pathological changes typical of myotubular myopathy. Energy-dispersive electron probe x-ray microanalysis was performed on 6- to 12-microns thick freeze-dried cryosections visualized in the scanning or scanning transmission mode of electron microscopy. We found a high intracellular sodium and chlorine concentration and a low potassium concentration in comparison with control muscles. These changes pointed in the direction similar to results from human fetal muscle. The changes in the intracellular elemental composition may indicate a membrane pump dysfunction, which might be caused by a partial arrest in muscle fiber maturation.

Adolescent↗
PubMed1982

Five different types of centrally nucleated muscle fibres in man: elemental composition and morphological criteria. A study of myopathies, fetal tissue and muscle spindle.

Muscle biopsy material from patients with two types of benign hereditary myopathy was explored with electron probe X-ray microanalysis performed on thick cryosections observed in a scanning electron microscope equipped for the analyses. The elemental spectra thus obtained were related to the ratio between cross-sectional areas of centrally located nuclei and corresponding muscle fibres. Fetal myotubes and intrafusal muscle fibres were examined by the same methods. One of the myopathies was characterized by fibres resembling myotubes ('myotubular myopathy') and exhibited elementary spectra with i.a. higher sodium and chlorine and lower potassium signals than normally found. These spectra have a tinge of those found in fetal muscle and in extrafusal muscle fibres. The other type of myopathy had less specific morphological characteristics and exhibited different pathological changes in the muscle fibres and i.a. central nuclei in a considerable number of fibres. These nuclei were, however, smaller in relation to the cross-sectional area of the corresponding fibres than in fetal myotubes, fibres in the myotubular myopathy and in the intrafusal muscle fibres. Elemental spectra of muscle fibres in the latter myopathy conformed to the normal state. We conclude that central nuclei of muscle fibres is a pathological phenomenon which can mirror an arrest in fibre development as well as a muscle fibre degeneration. An arrest in the development is suspected in myopathic muscle fibres with large central nuclei and an elevated content of sodium chlorine in the sarcoplasm.

Adolescent↗
PubMed1980

The separation of pineocytoma from pineoblastoma.

From our study of eight pineoblastomas and five pineocytomas and a review of the literature, we have described two clinicopathologic syndromes that characterize these neoplasms. Pineoblastomas highly resemble the medulloblastoma-neuroblastoma group of tumors and occur mostly in young people. The tempo of progression of the disease is fast, the length of illness is short. These are infiltrating neoplasms that commonly spread via the cerebrospinal fluid. They are radiosensitive. Histologically they are also similar to the medulloblastoma-neuroblastoma group and are characterized by the scarcity of cytoplasmic processes and by the Homer Wright rosette. They contain giant cells. Pineocytomas are tumors of adults. The tempo of progression of the disease is slow, and the length of illness is long. They expand by compressing the surrounding tissues. Histologically they are characterized by the abundance of cytoplasmic processes and by the pineocytomatous rosette. They contain giant cells. Areas composed of neoplastic gangliocytes and astrocytes in various combinations are common variants in some of these neoplasms.

Adolescent↗
PubMed1980

Hypothyroid myopathy. A clinical and pathologaical study.

Ten patients with varying degrees of hypothroid myopathy were studied clinically and by serial percutaneous needle muscle biopsies before and during treatment with L-thyroxine. The biochemical evidence of hypothyroidism was related to the severity of the myopathic and signs before treatment. The severity of myopathic symptoms before and during treatment correlated with the biochemical evidence of hypothyrodism, a type II fibre atrophy and increased central nuclear counts. Likewise, the clinical evidence of a myopathy before and during treatment was correlated with both a type II fibre atrophy and loss and increased central nuclear counts but was not related to the biochemical parameters of hypothyroidism, except the level of thyroid stimulating hormone. In the muscle, before and during treatment, of the two most severely affected patients, intracellular glycogen inclusions were seen in scattered muscle fibres. On light microscopy and on electronmicroscopy, numerous mitochondria were seen responding to L-thyroxine with accumulations of subsarcolemmal honey-combing. Vesicular abnormalities, an electron dense matrix or occasional crystalline deposits were seen in muscle mitochondria from less severely azffected patients. Severely myopathic muscle contained excessive glycogen, membrane bound glycogen and excess lipid in a mainly perinuclear distribution. Occasional myelin and membranous bodies were seen and satellite cells during the recovery phase. A group of patients with hypothyroid myopathy who are likely to have a delayed recovery of full muscle strength on L-thyroxine may be recognised by the presence of severe proximal muscle weakness and characteristic changes on histochemical and electronmicroscopic examination of muscle. The spectrum of histochemical and electronmicroscopic abnormalities of muscle revealed with increasing degree of hypothyrodism, suggests that a generally reversible acquired glycogen storage and mictochondrial disorder is an important feature in the pathogenesis of this condition.

Adult↗
PubMed1980

Ultrastructural changes of skeletal muscles in polyarteritis nodosa and in arteritis assoicated with rheumatoid arthritis.

Muscle biopsies from two cases of polyarteritis nodosa (PN) and one of arteritis in assoication with rheumatoid arthritis (RA) were examined by electron microscopy. The histological changes were similar in all three cases. The endothelial cells of the small blood vessels were often hypertrophied. Inflammatory reaction was present mainly in the vicinity of the blood vessels. Individual muscle fibres showed mostly nonspecific degenerative changes. In a case PN, however, annulate lamellae were present in a small number of the muscle fibres. The annulate lamellae have been reported, to our knowledge, in the human skeletal muscles only in a few cases of polymyositis. In addition, two cases, one of PN and of arteritis with RA, showed fine filamentous inclusions in the muscle fibres. Changes were also noted in the motor end-plate. A sural nerve biopsy in a case of arteritis with RA showed changes both in axons and myelin sheaths, in addition to the changes in the blood vessels similar to those in the muscle.

Aged↗
PubMed1980

The developing human muscle: ultrastructural differences between myoblasts and fibroblasts.

Material from foetuses of nine weeks to nine months development was examined by electron microscopy to obtain some information about the various stages in the development of skeletal muscle and structures which are intimately related to it, such as blood vessels, nerves, neuromuscular spindles, fibroblasts and their product, i.e., collagen. Regarding the myoblasts and fibroblasts it was interesting to compare their ultrastructural features since there has been some difficulty in the identification of these two types of mononucleated cells by the authors which deal with light microscopy in the study of developing skeletal muscle. It was possible to note that between nine and eighteen weeks of development the muscle is different from mature skeletal muscle and is composed predominantly of two populations of muscle cells. These are the myoblasts which are mononucleated cells and the myotubes which are multinucleated muscle cells. After eighteen weeks of development there occur only muscle fibres similar to those of adult muscle. Fibroblasts also occur frequently in the developing muscle: they too are mononucleated cells. Fibroblasts and collagen fibrils are seen between the muscle cells and structures related to them as early as nine weeks of development. Bundles of collagen were also seen in the cytoplasm of fibroblasts.

Collagen↗
PubMed1979

Fingerprint inclusions and circular structures in the muscle. Report of a case.

Fingerprint inclusions, circular structures of unknown origin, mitochondrial changes, dilatation of the sarcoplasmic reticulum, rods of Z-line material, elongated T-systems, honeycombs, and myelin figures were present in some damaged muscle fibres. Many damaged fibres showed loss of myofilaments and groups of atrophied fibres occurred. The muscle biopsy was from the left biceps brachii and presented also the changes of polymyositis. The patient had muscle weakness, malignant hypertension, alcoholism, polyarthropathy, and evidence of mild peripheral neuropathy.

Alcoholism↗
PubMed1979

Ultrastructural changes in polymyositis.

Muscle biopsies from 32 cases with polymyositis and dermatomyositis were examined by electron microscopy. Most of the changes of the muscle fibres were non-specific and little structural difference was seen in the various clinical types. The muscle fibres sometimes showed rough endoplasmic reticulum, annulate lamellae and prominent Golgi apparatus. Thin and thick filamentous inclusions were present both in the sarcoplasm and nuclei of some muscle fibres. Thick filamentous inclusions were seen in chronic cases and were sometimes associated with annulate lamellae. Regeneration of muscle was often conspicuous. The endothelial cells of the blood vessels were hypertrophied; some cells contained granulotubular inclusions, rod-shaped bodies (Weibel-Palade bodies) and filamentous material. The basement membrane of the vessels was often multi-layered. The cells infiltrating the interstitial tissue included macrophages, lymphocytes, transformed lymphocytes, plasma cells, monocytes, mast cells and only occasional eosinophils and basophils. Lymphocytes, macrophages and a few plasma cells were seen between the plasma and basement membranes of degenerating muscle fibres. Changes were also noted in some intramuscular nerves, motor end-plates and a muscle spindle.

Adolescent↗
PubMed1979

Memory disorder in Korsakoff's psychosis: a neuropathological and neuropsychological investigation of two cases.

Neuropathological findings in the brains of two alcoholic patients with Korsakoff's psychosis are reported. Their memory defects had been studied in detail quantitatively over a period of nine years in one case and three years in the other, relevant details of which are presented. Both patients had had a relatively pure long-term memory impairment in the absence of other cognitive deficits and in the absence of a short-term memory impairment. Their retrograde amnesia for public events and famous faces had been measured and found to have extended backwards over at least twenty-five years. There was severe impairment in anterograde recognition memory for both verbal and non-verbal material. On a newly prepared memory quotient battery both patients had scored well below the bottom of the normal scale (less than 60, where 100 is the mean with a standard deviation of +/- 15). Both patients had also shown the characteristic differential improvement in retention when tested by cued recall and also the characteristic 'prior learning effect', i.e. normal retention of one list of words when tested by cued recall but impaired retention of a second list sharing the same cues as the first list. There had been a slight but significant deterioration in intelligence in one of the patients in the two years prior to his death, although his IQ still fell within the normal range. The other patient remained undeteriorated until his death, and his IQ also was close to an estimated measure of his premorbid IQ. In the brains of both patients there was marked gliosis, shrinkage and discolouration bilaterally in the medial nuclei of the mammillary bodies. In addition there was a thin band of gliosis bilaterally between the wall of the third ventricle and the medial dorsal nucleus, the rostral limit lying anterior to the medial dorsal nucleus. In the patient with no intellectual deterioration these were the only pathological changes that were seen. In neither patient was there evident local loss of nerve cells, gliosis or any other qualitative evidence of abnormality in the hippocampi, the white matter of the temporal lobes or the greater part of the medial dorsal nuclei, although it is difficult to be certain whether there was any overlap between the band of gliosis and the most medial region of the medial dorsal nueleus and other adjacent thalamic nuclei. In the other patient there was also a small zone of softening in the cerebellum and an increase in astrocytes in other regions of the cerebral hemispheres, including the basal ganglia, amygdala, and brain-stem, but without noticeable loss of cells. The question of the minimal lesion for the alcoholic Korsakoff amnesic state, and some aspects of the related anatomy, is discussed in the context of other reports in the literature which are, however, difficult to assess in the absence of details of the specificity, severity and character of the memory disorders.

Aged↗
PubMed1979

Ultrastructure of human intramuscular blood vessels in development.

Muscles from human foetuses of nine weeks to nine months development were examined by electron microscopy. Capillaries, arteries and veins are frequent in the human foetal muscle at all stages of development. At nine weeks the vessels have the appearance of capillaries and basement membrane lies around the endothelial cells forming them. The capillaries are of continuous type which do not have apertures in their walls. Tight junctions are seen at some zones of adjacent endothelial cells of the capillaries. Sometimes, pericytes are also seen. At sixteen weeks vessels having the features of veins and of arteries can be identified between the muscle cells. Regarding the arteries, some of the endothelial cells are united to the smooth muscle cells and the intimal elastic lamina is interrupted where these cells approximate. The significance of this junction may be to anchor the intima to the media.

Arteries↗