Biomedical subjects

G R Kelley

Publications and source records attributed to G R Kelley.

3 recordsLinked to original sources

PubMed1998

Food restriction alters the age-related decline in cardiac beta-adrenergic responsiveness.

The responsiveness of the heart to beta-adrenergic receptor stimulation declines with age. The aim of this study was to determine whether food restriction (FR), the most effective means of retarding the aging processes, affects the loss of beta-adrenergic responsiveness. Male Fisher 344 rats, fed either ad libitum (Group A) or allowed to eat only 60% of what Group A rats consumed (Group B), were sacrificed at 4, 11 or 22-28 months of age. The hearts were isolated and perfused via the Langendorff method. Ventricular pressure-volume curves were constructed to determine the optimal volume for pressure development and concentration-response curves to isoproterenol were obtained at this optimal volume. Interestingly, the ventricular pressure-volume curve for 4 month Group B lay to the left of all the other groups, suggesting that hearts from younger FR rats possessed higher contractility than the other groups. In the unstimulated heart, aging was associated with a slower relaxation phase of contraction and FR further slowed the relaxation. The maximum response of the heart to isoproterenol declined with age and the decline was unaffected by FR. The concentration-response curves of hearts from older rats were generally shifted to the right of the younger animals, while FR shifted the curves to the left toward greater sensitivity to beta-adrenergic stimulation. The EC50s for isoproterenol increased with age, indicating a decrease in the responsiveness of the heart to beta-adrenergic receptor stimulation. In contrast, FR decreased the isoproterenol EC50, suggesting an enhanced responsiveness. These results demonstrate that FR can retard some aging changes (loss in beta-adrenergic responsiveness), while it enhances others (increase in relaxation times).

Adrenergic beta-Agonists↗

PubMed1986

Herpes simplex virus encephalitis. A case with dysplastic plasma cell infiltration.

A case of herpes simplex virus (HSV) encephalitis was diagnosed by means of a brain biopsy specimen on the 31st day of the illness. The infiltrate showed dense plasma cells, with dysplastic features that mimicked plasma cell neoplasm. The diagnosis of HSV encephalitis was substantiated by the finding of intranuclear virus particles and by seroconversion with HSV-specific enzyme-linked immunosorbent assay tests in blood serum and cerebrospinal fluid. This histologic appearance correlated temporally with the time of peak seroconversion. Extensive plasma cell infiltrate may be an unrecognized variant of the histopathology of HSV encephalitis in its subacute phase, and only careful electron microscopic study will establish the diagnosis.

Adult↗

PubMedDate not supplied

Magnetic resonance imaging in multiple sclerosis: results in 32 cases.

A prospective clinical study was performed in 32 patients with multiple sclerosis (MS) to evaluate the sensitivity of lesion detection and accuracy of lesion localization by neurologic examination, delayed enhanced computed tomography (CT) with a double dose of contrast material, and proton magnetic resonance (MR) imaging. After neurologic examination patients were classified by probability of MS (possible, four patients; probable, three patients; and definite, 25 patients) and by disease activity (acute, chronic with acute exacerbation, or chronic progressive). Subsequently they underwent delayed enhanced CT scanning and MR imaging with more than one spin-echo technique. In five of seven patients with possible or probable MS, both MR imaging and delayed enhanced CT were negative. In 25 cases of definite MS, MR imaging detected pathology in 19 (76%) cases, while CT detected lesions in 15 (60%) of 25 cases. In acute lesions (acute or chronic with acute exacerbation), the two techniques were of similar sensitivity (delayed CT was positive in 65% and MR imaging in 60%), while in chronic progressive MS, MR imaging was superior in lesion detection (MR imaging positive in 75%; delayed CT in 25%). While most lesions (55%) were seen in corresponding locations in both studies, neither MR nor delayed CT correlated well with lesion localization by neurologic examination because a large number of asymptomatic lesions were imaged and many symptomatic lesions were undetected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗