Biomedical subjects

K M Sanders

Publications and source records attributed to K M Sanders.

256 records · Page 15Linked to original sources

PubMedDate not supplied

Separation of two Cl(-) currents in cultured human and murine mesangial cells: biophysical and pharmacological characteristics of I(Cl.vol) and I(Cl.Ca).

Mesangial cells, a combined smooth muscle- and fibroblast-like phenotype, are important regulators of renal function. These cells exist in a region of variable osmolarity and may require Cl(-) channels for volume regulation. Additionally, Ca(2+)-activated Cl(-) channels in these cells may participate in Ca(2+)-dependent contractile responses to vasoactive agonists. Relatively little, however, is known about mesangial cell Cl(-) currents (I(Cl)); including the biophysical description and pharmacological characterization. We used whole-cell patch clamp to study I(Cl) in cultured human and SV40-transformed murine mesangial cells. I(Cl) was measured in cells dialyzed and bathed with symmetrical N-methyl-D-glucamine chloride solutions to minimize cation currents. Dialysis with buffers to control intracellular Ca(2+) ([Ca(2+)](i)), extracellular solutions of varied osmolarity, and manipulation of the transmembrane Cl(-) gradient were used to separate two currents: I(Cl.vol) (volume-sensitive), and I(Cl.Ca) (Ca(2+)-activated). In symmetrical Cl(-) with low [Ca(2+)](i), I(Cl.vol) was outwardly rectifying and modulated by osmolarity. I(Cl.vol) demonstrated slight time- and voltage-dependent inactivation. In symmetrical Cl(-) with elevated [Ca(2+)](i) and hypertonic bath, I(Cl.Ca) was linear, but in asymmetrical Cl(-) (low [Cl(-)](i)) was outwardly rectifying and demonstrated time- and voltage-dependent activation. Permeability sequences for both I(Cl.vol) and I(Cl.Ca) were I(-) > Br(-) > Cl(-) > F(-); however, there were differences in the relative magnitudes. Tamoxifen inhibited I(Cl.vol) more potently than I(Cl.Ca), whereas niflumic acid inhibited I(Cl.Ca) more potently than I(Cl.vol). We have separated and characterized two types of I(Cl) in cultured human and murine mesangial cells. I(Cl.Ca) and I(Cl.vol) have different biophysical and pharmacological characteristics. These observations on I(Cl.Ca) and I(Cl.vol) may provide insight into mesangial cell reactivity and volume regulation.

Animals↗

PubMedDate not supplied

Geriatric epilepsy: a review.

After the turn of the century, the proportion of population over 60 years of age is expected to be over 20%. Recent epidemiologic studies show a higher incidence of new-onset epilepsy in the population over 60 years of age compared with preceding decades of life. The predominant seizure type in up to 80% of these new cases of epilepsy is simple and complex partial manifestation. This paper reviews the literature documenting the increased incidence of partial seizures in the aging population, explores the known etiologies of new-onset epilepsy, and uses five case vignettes presenting with complex partial symptomatology.

Aged↗

PubMedDate not supplied

Neuro-Behçet's disease.

We are reporting a case of Behçet's disease without vasculitis, but with acute neutrophilic inflammation which involved the brain and other organs. The patient exhibited waxing and waning neurological deficits which were unresponsive to treatment. The neuroradiologic findings simulated those of multiple sclerosis. The neuropathological examination revealed an acute, focal, though disseminated encephalitis involving the frontal lobe, internal capsule, basal ganglia, cerebellum, and brain stem. The acute inflammation consisted of a neutrophilic and eosinophilic infiltration of the perivascular spaces and parenchyma without evidence of vasculitis, fibrinoid necrosis, or thrombosis. Cultures and special stains for microbial organisms were negative. Ultrastructural examination revealed no viral structures or other microorganisms. In situ hybridization for Epstein-Barr virus (EBV), herpes simplex virus type I (HSVI), and cytomegalovirus (CMV) was negative. In this case, the lack of inflammation in the vessel walls points out that the necrotizing lesions in neuro-Behçet's disease need not be the result of vasculitis and superimposed thrombosis, but may occur as a result of primary, acute neutrophilic inflammation.

Adult↗

PubMedDate not supplied

Neuro-Behçet's disease.

We are reporting a case of Bechçet's disease without vasculitis but with acute neutrophilic inflammation which involved the brain and other organs. The patient exhibited waxing and waning neurological deficits which were unresponsive to treatment. The neuroradiologic findings simulated those of multiple sclerosis. The neuropathological examination revealed an acute, focal, though disseminated encephalitis involving the frontal lobe, internal capsule, basal ganglia, cerebellum, and brainstem. The acute inflammation consisted of a neutrophilic and eosinophilic infiltration of the perivascular spaces and parenchyma without evidence of vasculitis, fibrinoid necrosis, or thrombosis. Cultures and special stains for microbial organisms were negative. Ultrastructural examination revealed no viral structures or other microorganisms. In situ hybridization for Epstein-Barr virus (EBV), herpes simplex virus type I (HSV-I), and cytomegalovirus (CMV) was negative. In this case, the lack of inflammation in the vessel walls points out that the necrotizing lesions in neuro-Bechçet's disease need not be the result of vasculitis and superimposed thrombosis, but may occur as a result of primary, acute neutrophilic inflammation.

Acute Disease↗