Biomedical subjects

M M Froes

Publications and source records attributed to M M Froes.

3 recordsLinked to original sources

PubMed2002

Cell migration in the postnatal subventricular zone.

New neurons are constantly added to the olfactory bulb of rodents from birth to adulthood. This accretion is not only dependent on sustained neurogenesis, but also on the migration of neuroblasts and immature neurons from the cortical and striatal subventricular zone (SVZ) to the olfactory bulb. Migration along this long tangential pathway, known as the rostral migratory stream (RMS), is in many ways opposite to the classical radial migration of immature neurons: it is faster, spans a longer distance, does not require radial glial guidance, and is not limited to postmitotic neurons. In recent years many molecules have been found to be expressed specifically in this pathway and to directly affect this migration. Soluble factors with inhibitory, attractive and inductive roles in migration have been described, as well as molecules mediating cell-to-cell and cell-substrate interactions. However, it is still unclear how the various molecules and cells interact to account for the special migratory behavior in the RMS. Here we will propose some candidate mechanisms for roles in initiating and stopping SVZ/RMS migration.

Animals↗

PubMed1990

Histomorphometric and histopathological study of the human cricopharyngeus muscle: in health and in motor neuron disease.

Abnormalities in muscle histology have been reported frequently for the cricopharyngeus muscle of patients with oculopharyngeal muscular dystrophy, motor neuron disease and other neurological disorders in which dysphagia is a common clinical sign. However, there are few detailed reports of the normal structure of this muscle nor quantitative baseline data with which to compare the diseased state. In this study, cricopharyngeus muscles from 21 healthy individuals and four patients with motor neuron disease underwent quantitative histological and histochemical examination. In addition to the extensive connective tissue content (40%), comprising abundant elastic fibres, cricopharyngeus muscles from normal individuals possessed small calibre striated muscle fibres (mean narrow diameter 30 microns) of widely varying size (coefficient of variation 41%). The majority of fibres were histochemically type I (82%) and highly oxidative. All muscles comprised numerous muscle fibres with aberrant histological and histochemical features (internalized nuclei, 'ragged red' crescents, splits, degenerating fibres, 'moth-eaten' fibres, or nemaline rods.) The histomorphometric and histopathological features were similar in males and females and some showed a correlation with age. There were increases in fibre size and roundedness and decreases in the numerical density and percentage of type I and split fibres in the specimens from older individuals. Cricopharyngeus muscles from patients with motor neuron disease were not significantly different from the controls for most parameters. It is therefore suggested that previous descriptions of specific cricopharyngeal pathology accompanying neuromuscular disease or dysphagia be interpreted with caution. The importance of obtaining normal structural, morphometric and histopathological data from muscles other than the usually biopsied limb muscles, is emphasized.

Adult↗

PubMedDate not supplied

Muscle morphometry in motor neuron disease.

It has previously been suggested that the pathological abnormalities seen in muscle biopsies from patients with motor neuron disease (MND) are of predictive value in relation to the rate of progression of the disease. In this study, quadriceps muscle biopsies from 19 patients with MND and 20 age matched controls were prepared for histochemistry and analysed morphometrically. Pathological features of denervation and reinnervation were observed in all MND patients although considerable variation between patients was noted. Motor neuron disease biopsies also showed increased connective tissue, an increased variation in fibre size, and a random fibre type distribution. Several of these abnormalities were more severe in female patients. Many of these 'abnormalities' were also frequent, albeit to a milder degree, in control biopsies and emphasize the need for age matched controls. The morphometric data was not related to the age of the patient, disease duration, type of MND or muscle strength, thus suggesting that the progression and severity of MND and its prognosis cannot be judged on the basis of quadriceps muscle pathology alone.

Adult↗