PubMed Health⌕ Search

Biomedical subjects

K M Welch

Publications and source records attributed to K M Welch.

At least 181 records · Page 10Linked to original sources
PubMed1987

Recurrent stroke associated with thymoma and anticardiolipin antibodies.

A 44-year-old woman developed recurrent thrombotic cerebral cortical infarctions. IgG and IgM anticardiolipin antibodies were found, as was a thymoma. To our knowledge, these antiphospholipid antibodies, which may inhibit prostacyclin formation and alter platelet function, have not been previously associated with this thymic neoplasm, an association we believe is not coincidental.

Adult↗
PubMed1987

The spectrum of neurologic disease associated with antiphospholipid antibodies. Lupus anticoagulants and anticardiolipin antibodies.

Lupus anticoagulants and anticardiolipin antibodies are antiphospholipid immunoglobulins, predominantly of the IgG, IgM, or mixed class. Recently, these antiphospholipid autoantibodies have been associated with neurologic conditions including focal cerebral and ocular ischemia, the myelopathy of lupoid sclerosis and Degos' disease, Guillain-Barré syndrome, migraine, chorea, and seizures. We review the neurologic manifestations associated with this group of antibodies. Recognition of these conditions may lead to further insights into pathogenesis and therapy.

Autoantibodies↗
PubMed1987

The development of a pH-sensitive contrast agent for NMR 1H imaging.

Fe(III)meso-tetra(4-sulfonatophenyl)porphine (Fe-TPPS4) has been investigated as a potential pH-sensitive nuclear magnetic resonance (NMR) proton image contrast agent. Relaxation rates (1/T1 and 1/T2) of water protons were measured as a function of pH and concentration of Fe-TPPS4 in phosphate-buffered isotonic saline. Transverse relaxation rates (1/T2) did not change appreciably with pH above 6.0. Longitudinal relaxation rates (1/T1) increased significantly between pH 7.75 and 5.75. This effect was more pronounced with the increasing concentration of Fe-TPPS4 from 0.1 to 1.5 mM and is attributed to a pH-dependent equilibrium between the high-spin (S = 5/2) Fe-TPPS4 monomer at low pH and the antiferromagnetically coupled mu-oxodimer O-(FeTPPS4)2 at high pH. The efficacy of this pH-dependent contrast agent is demonstrated in vitro.

Contrast Media↗
PubMed1987

Migraine and the lupus anticoagulant. Case reports and review of the literature.

Lupus anticoagulants (LA) are antiphospholipid serum immunoglobulins generally associated with autoimmune conditions, especially systemic lupus erythematosus (SLE). They have recently been linked to thrombotic events, including stroke. A possible association of migraine with LA is now forwarded with the presentation of two cases and a literature review. Our two patients, both in their forties, had migrainous phenomena without SLE or thrombotic events. Eight other cases were found in the literature, suggesting more than a chance association. Relevance to migraine pathophysiology is discussed and may come from the ability of the LA to alter prostaglandins and platelet activity and to interact with neuronal phospholipids. Further, larger studies are needed to support this association.

Adult↗
PubMed1987

Asymmetric cerebral blood flow patterns in migraine.

Although asymmetric EEG abnormalities have been reported during the headache-free period in migraineurs, asymmetries of regional cerebral blood flow (rCBF) have not been studied. Headache-free rCBF values measured by 133Xe inhalation were lower in migraineurs than in controls. Interhemispheric CBF and regional (anterior versus posterior) CBF did not differ between the groups. When a novel scoring system was used to obtain a mean asymmetry index (MAI), the MAI of the classic/complicated group was significantly higher than that of the controls but not significantly different from that of the common migraine group. These data suggest that in the headache-free interval rCBF asymmetries, variable in location, exist in classic/complicated migraineurs. These rCBF changes may be related to the cause or the effect of the focal neurologic dysfunction that occurs during an attack in these patients.

Adult↗
PubMed1987

Photodynamic therapy of normal cerebral tissue in the cat: a noninvasive model for cerebrovascular thrombosis.

The early neuropathological response of normal cat brain to photodynamic therapy was investigated. Photofrin II was injected (IV) into a cat and photoactivated with red light from a filtered incandescent lamp. Animals were subjected to phototherapy either through the intact skull or with energy deposition onto the intact dura. Following photoactivation the animals were maintained for 6 h after which time the brain was removed and sections submitted for electron microscopic and or light microscopic study. Gross anatomical analysis of the photoactivated brain revealed hemorrhagic dusky discoloration limited to the area of the tissue illuminated. Animals that failed to show a lesion were cats characterized by low Photofrin II dosage and low photoactivation intensity. The microscopic cortical features of cats with lesions included prominent capillary congestion and regions of marked vacuolization and rarefaction. Blood vessels were structurally altered and the lumen of many vessels was completely filled with tightly packed erythrocytes. Our study suggests that the acute neuropathological response of cerebral tissue to photoactivation resembles that of microvascular thrombosis. It is thus reasonable to explore PDT of normal tissue as a non invasive model of cerebrovascular thrombosis in the cat.

Animals↗
PubMed1987

"Crack" cocaine-associated stroke.

We present three cases of "crack" cocaine-associated stroke, together with a review of cocaine-associated cerebrovascular complications. Unlike previously reported cases tentatively associating ischemic stroke with cocaine, our patients had no other potential causes for their strokes. Although the exact mechanism of cocaine-related stroke remains uncertain, both disordered neurogenic control of the cerebral circulation as well as systemic factors (ie, acute hypertension) may play a role.

Adult↗
PubMed1986

In vivo evaluation of intracellular pH and high-energy phosphate metabolites during regional myocardial ischemia in cats using 31P nuclear magnetic resonance.

Phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) was used to assess the temporal changes of high-energy phosphate metabolites in the region of acute myocardial ischemia of open-chest cats. Eight anesthetized cats were studied following ligation of the left anterior descending coronary artery. Creatine phosphate showed a 79 +/- 16% (mean +/- SD) reduction by 4 min after the onset of ischemia. Prominent qualitative reductions of the spectral peak of creatine phosphate occurred by 40 s after ischemia. Adenosine triphosphate measured under the beta spectral peak (beta-ATP) decreased 37 +/- 9% by 20-25 min after ligation of the left anterior descending coronary artery. These reductions developed more slowly and were of smaller magnitude than those of creatine phosphate. Intracellular pH decreased from 7.39 +/- 0.07 to 7.13 +/- 0.09 units by 40 s after ischemia. By 30 min, pH decreased to 6.07 +/- 0.40 units. The study shows, therefore, the temporal changes of high-energy phosphate metabolites during ischemia in localized regions of the myocardium of open-chest animals.

Adenosine Triphosphate↗