Distribution of neurons and glia in the visual cortex (area 17) of the adult albino rat: a quantitative description

The neuronal and glial cell composition of the rat visual cortex (area 17) has been determined quantitatively using stereological techniques. The volume numerical densities (number of cells per mm3 of cortex) of neurons and of the principal glial cell types (astroglia, oligodendroglia, and microglia) were calculated from tangential semithin resin sections spaced at regular intervals 50 micron apart throughout the entire depth of the visual cortex. From measurements of cortical and laminar thickness the separate volume numerical densities of neurons and glial cells were derived for each lamina in the cortex. In addition, the absolute numbers of cells in each lamina under 1 mm2 of cortical surface were calculated. The mean cortical volume numerical density of neurons was 60,020 +/- 3840/mm3 (mean +/- SEM; n = 8), and 49,040 +/- 2610/mm3 for the combined glial cell types. Astroglia, oligodendroglia, and microglia were present in a ratio of 6:3:1 respectively. It was determined from neuronal and glial somatic volume estimates that the somata of these cells occupied approximately 13.5% of unit cortical volume, with 81.3% of the unit volume being occupied by cortical neuropil. Using previously published reports that described the laminar composition of neurons in terms of the relative proportions of pyramidal and non-pyramidal cells, the laminar volume numerical densities for these neuronal categories have been derived. In addition, it has been estimated that under 1 mm2 of cortical surface there are 79,500 pyramidal and 7790 non-pyramidal neurons distributed throughout layers 1-6 of the rat visual cortex.     

Effects of antidepressant medication on sexual function: a controlled study

There has been little systematic study of the types of sexual dysfunction produced by antidepressant medication or of the frequency with which this type of adverse effect occurs. The authors report results of a double-blind study in which the effects of imipramine, phenelzine, and placebo on specific aspects of sexual function were assessed in depressed outpatients before and after 6 weeks of treatment. Both active treatments were associated with a high incidence of adverse changes in sexual function and produced significantly more adverse effects on sexual function than placebo. Orgasm and ejaculation were impaired to a greater extent than erection. Adverse sexual function changes secondary to antidepressant medication occurred frequently in both men and women, although men reported a higher incidence. Antidepressant-related sexual dysfunction may be of clinical importance for medication compliance in view of current recommendations that antidepressants be administered for longer periods as maintenance therapy or for prophylaxis.     

Determinants of health-service use by low-income people.

Poverty influences health status, life expectancy, health behaviours, and use of health services. This study examined factors influencing the use of health-related services by people living in poverty. In the first phase, 199 impoverished users of health-related services in 2 large Canadian cities were interviewed by their peers. In the second phase, group interviews with people living in poverty (n = 52) were conducted. Data were analyzed using thematic content analysis. Diverse health-related services were used to meet basic and health needs, to maintain human contact, and to cope with life's challenges. Use of services depended on proximity, affordability, convenience, information, and providers' attitudes and behaviours. Use was impeded by inequities based on income status. To promote the health of people living in poverty, nurses and other health professionals can enhance the accessibility and quality of services, improve their interactions with people living in poverty, provide information about available programs, offer coordinated community-based services, collaborate with other sectors, and advocate for more equitable services and policies.     

Long-term effects of glaucoma therapy with 4% pilocarpine gel on corneal clarity and endothelial cell density

Corneal thickness measurements and endothelial cell counts were carried out in 34 patients undergoing treatment for glaucoma with 4% pilocarpine gel between 18 to 78 months after initiation of therapy. The corneal thickness and endothelial cell population were found to be within normal limits in all cases except two, one patient with increased corneal thickness who had recently undergone cataract and glaucoma filtering surgery and another patient with decreased cell count who had an old endothelial scar sustained prior to pilocarpine gel therapy. There was a very close correlation for both of these parameters noticed in patients treated with pilocarpine gel and in age-matched control group of patients with glaucoma. The present study has shown that there are no adverse corneal effects with pilocarpine gel therapy.     

Corticomotoneuronal dysfunction in ALS patients with different SOD1 mutations.

OBJECTIVE: To examine corticomotoneuronal function in amyotrophic lateral sclerosis (ALS) patients carrying superoxide dismutase 1 (SOD1) mutations using peristimulus time histograms (PSTH). METHODS: Six I113T, 3 A4V, one G41D and one G114A patient were studied along with 21 healthy control subjects. Analyses included comparison with previously reported data from 8 D90A homozygous and 12 sporadic ALS (SALS) patients examined by the authors using identical methodology. RESULTS: Cortical threshold was significantly reduced in A4V patients (41.3%) compared to I113T (58%), SALS (57%) and D90A (71%) patients, as well as healthy controls (49.7%). Estimated excitatory postsynaptic potentials (EPSPs) were significantly larger in A4V patients (4.39 mV) compared to healthy controls (2.95 mV), I113T (2.71 mV) and SALS (2.39 mV) patients. Clinical features and PSTH parameters in I113T were similar to SALS, however, PSTH primary peaks (PP) were significantly more dispersed, 9.5 ms compared to 4ms in SALS. PSTHs from single G41D and G114A patients were unremarkable, apart from large EPSP amplitudes in the G114A patient. CONCLUSIONS: ALS patients with A4V and I113T SOD1 mutations have distinctive corticomotoneuronal changes that are different from those in D90A homozygous and SALS patients. SIGNIFICANCE: PSTH studies should be considered for future in vivo studies of SOD1 pathophysiology in ALS.