Biomedical subjects

J A Valone

Publications and source records attributed to J A Valone.

8 recordsLinked to original sources

PubMed1984

Senile reticular pigmentary degeneration.

Of 104 consecutive patients with senile reticular pigmentary degeneration (207 eyes), 85 patients (82%) were more than 60 years old (mean age, 69.2 +/- 8.54 years). Forty-nine (47%) were men and 55 (53%) were women. Peripheral visual fields were not characteristically constricted. Although most eyes tested had visual acuities of 20/50 or better, 69 eyes (33%) had visual acuities of 20/100 or worse. A total of 136 eyes (66%) had senile macular degeneration at the time senile reticular pigmentary degeneration was first diagnosed, whereas only 43 control eyes (21%) from the same referral population also had senile macular degeneration (P less than .001). Macular degeneration was the primary cause for reduced vision when it was noted. In no instance could reduced visual acuity or constricted visual fields be attributed to the senile reticular pigmentary degeneration alone. Senile reticular pigmentary degeneration on routine ophthalmoscopy should alert the clinician to the possibility of co-existing macular degenerative disease.

Aged↗

PubMed1981

Unilateral proliferative diabetic retinopathy. I. Initial findings.

The combination of unilateral proliferative diabetic retinopathy (PDR) in one eye and nonproliferative diabetic retinopathy (NPDR) in the fellow eye was observed in 10.1% of patients with PDR. Most patients were between the ages of 50 and 70 years; the majority had adultonset diabetes mellitus. Unilateral aphakia and anisometropia of greater than 1 diopter were both infrequently seen. The incidence of glaucoma was unremarkable. Unilateral elevated-but not necessarily abnormal-intraocular pressure was found in a significantly larger proportion of eyes with NPDR (20%) than with PDR (12%). Most patients had moderate to severe angiopathy or exudation in the eye with NPDR and modest PDR in the fellow eye; however, one third had moderate to severe PDR. In only 2% of the patients was visual acuity less than 20/200 on initial examination.

Adult↗

PubMed1981

Unilateral proliferative diabetic retinopathy. II. Clinical course.

One hundred thirty-six patients with proliferative diabetic retinopathy (PDR) in one eye and nonproliferative diabetic retinopathy (NPDR) in the fellow eye on initial examination were followed up for at least three months. Eight percent of the eyes with NPDR were eliminated from further consideration by treatment within the first three months. Proliferative diabetic retinopathy developed in 58% of the remaining eyes with NPDR, usually within two years of the initial examination. Proliferative diabetic retinopathy developed in a significantly greater percentage of diabetics who were younger than 40 years than in diabetics older than 60 years. Poor visual prognosis among eyes that initially had NPDR was associated with advanced angiopathy or exudation on initial examination and also may have been associated with the subsequent development of PDR. Neither the development of PDR nor the final visual acuity in these eyes could be correlated with vascular disease outside the eye, the degree of PDR in the fellow eye, or the presence of higher intraocular pressure in the eye with NPDR on initial examination. Forty-one percent of the eyes with unilateral PDR were eliminated from consideration by prompt treatment. Most remaining eyes with PDR also showed progressive fundus pathologic conditions.

Adult↗

PubMed1978

Severe adolescent-onset proliferative diabetic retinopathy: the effect of pituitary ablation.

Proliferative diabetic retinopathy (PDR) is uncommon in patients younger than the age of 20 and has been rarely reported. Since 1969, 14 adolescents with severe PDR have been seen, the youngest of whom was 16 years old and the oldest, 19 years old. The shortest duration of diabetes mellitus prior to diagnosis of PDR was eight years. Ten patients had a positive family history of diabetes. Thirteen patients had suboptimal metabolic control. Ten patients had some degree of azotemia, seven were hypertensive, and six had proteinuria. Ophthalmic findings included advanced neovascular and fibrous proliferation on initial classification, and rapid progression to blindness-which was most frequently secondary to traction retinal detachment. In a small retrospective study, pituitary ablation may have offered greater preservation of vision than that observed in untreated patients.

Adolescent↗

PubMed1978

Bacterial adherence in the pathogenesis of endocarditis. Interaction of bacterial dextran, platelets, and fibrin.

The role of dextran in the pathogenesis of bacterial endocarditis was investigated by studying the adherence of dextran producing oral streptococci to the constituents of nonbacterial thrombotic endocarditis (NBTE) in vitro and in vivo. The adherence of Streptococcus sanguis to fibrin and platelets was determined in an in vitro assay system simulating nonbacterial thrombotic endocarditis. Adherence was increased when the organisms were grown in sucrose-supplemented media (adherence ratio X 10(4), 177 +/- 6 in 5% sucrose vs. 140 +/- 7 in 0.5% sucrose, P less than 0.001), and decreased by incubating the organisms in dextranase (adherence ratio X 10(4), 117 +/- 16, P less than 0.001), an effect which was nullified by heat inactivating this enzyme (adherence ratio X 10(4), 192 +/- 7, P less than 0.001). The amount of dextran produced in broth by three different oral streptococci correlated directly with the adherence observed to fibrin and a fibrin-platelet matrix in vitro (P less than 0.001). These organisms adhered more readily to a fibrin-platelet matrix than to fibrin alone (adherence ratio X 10(4), 455 +/- 30 vs. 177 +/- 6, respectively, P less than 0.001). The role of dextran formation was also examined in vivo in rabbits with preexisting NBTE. After injection of 10(7) S. sanguis, 12 of 17 animals developed endocarditis. In contrast, when the organisms were pretreated with dextranase (an enzyme that removes dextran from the bacterial cell surface), the same inoculum resulted in endocarditis in only 5 of 19 animals (P less than 0.05). In addition, a fresh strain of S. sanguis that produced high levels of dextran (1,220 +/- 50 microgram/ml) and adhered avidly to fibrin (adherence ratio X 10(4), 220 +/- 11) produced endocarditis in 12 of 18 rabbits after injection of 10(7) organisms. Another isolate of the same strain that had been passed repeatedly in the laboratory produced less dextran (400 +/- 30 microgram/ml), adhered poorly to fibrin (adherence ratio X 10(4), 140 +/- 7), and produced endocarditis in only 3 of 14 rabbits under identical conditions (P less than 0.05). This study demonstrates that dextran production is important in the adherence of oral streptococci to the constituents of NBTE and may play a role in the pathogenesis of bacterial endocarditis by oral streptococci.

Animals↗

PubMed1975

Diffuse glomerulonephritis in rabbits with Streptococcus viridans endocarditis.

Intravenous administration of live microorganisms to rabitts with cardiac catheters produces an experimental model of infective endocarditis. Despite the development of infected valvular vegetations, positive blood cultures, splenomegaly, and focal embolic renallesions, glomerulonephritis has not been found in these animals. In the present study, acute diffuse proliferative glomerulonephritis, featuring endothelial and mesangial proliferation, capillary occlusion, and leukocytic infiltration was produced in rabbits immunized withthe infecting agent prior to the establishment of left sided alpha-streptococcal endocarditis. Controls receiving immunization alone, immunization and sterileendocarditis, or infective endocarditis alone did not develop diffuse glomerulonephritis. Electron microscopic findings of occasional subendothelial electron-dense deposits and immunofluorescence deposition of IgG and C3 in a peripheral granular capillary pattern were consistent with an immune complex type nephritis. Decreased serum complement levels were demonstrated in those animals developing diffuse glomerulonephritis, and some animals developed circulating rheumatoid factor. In view of the morphologic findings and the necessity of preimmunization for development of glomerular changes, it is concluded that immune mechanisms play a role in the diffuse glomerulonephritis associated with this model of infective endocarditis.

Animals↗

PubMed1971

Constitutive mutants in a regulatory gene exerting positive control of quinic acid catabolism in Neurospora crassa.

In Neurospora crassa, evidence has recently been obtained for a cluster of four closely-linked genes controlling the inducible enzymes catalyzing the first three reactions in the catabolism of quinic acid. Three of these genes appear to be the structural genes for the three enzymes. The fourth gene, designated qa-1, has been interpreted as having a regulatory function, since qa-1 mutants are pleiotropic types, are noninducible for the three enzymes, and form heterocaryons which complement mutants in the structural genes. The present studies were undertaken to elucidate further the nature of the regulatory role of the qa-1 locus. A number of constitutive (qa-1(C)) mutants have been obtained from certain qa-1 mutants as revertants selected for their ability to grow on quinic acid as a sole source of carbon. These qa-1(C) mutants produce high levels of all three enzymes in the absence of an inducer, map within (or very close to) the qa-1 locus, and produce a catabolic dehydroquinase (EC 4.2.1.10) which is indistinguishable, on the basis of thermolability tests, from that of wild type. In addition, when grown in the absence of an inducer, heterocaryons between wild-type (qa-1(+)) and different qa-1(C) mutants exhibit markedly different levels of constitutivity (from 5 to 50% of the particular parental qa-1(C) mutant) for catabolic dehydroquinase, one of the enzymes under qa-1 control. These overall results are interpreted as supporting the hypothesis that the qa-1(+) gene product (presumably a multimeric protein) plays only a positive regulatory role in initiating synthesis of the three quinate catabolic enzymes.

Alcohol Oxidoreductases↗

PubMedDate not supplied

Acute orbital pseudotumor with iatrogenic intraorbital air: a diagnostic dilemma.

A 13-year-old black female was referred with unilateral granulomatous uveitis and orbital inflammation of sudden onset. Hematologic, serologic, bacteriologic, and ultrasonographic studies along with high resolution CT scans of the orbits were employed to determine the diagnosis and appropriate treatment. Subconjunctival corticosteroid injection containing air prior to referral obfuscated the ultimate diagnosis of pseudotumor. The Pediatric Infectious Disease service delayed definitive treatment with systemic steroids. Differential diagnosis of granulomatous uveitis with orbital inflammation are discussed. CT scan has significantly advanced the diagnosis and management of orbital pseudotumor.

Acute Disease↗