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L Duffy

Publications and source records attributed to L Duffy.

52 records · Page 3Linked to original sources
PubMed1988

Partial sequence of MAP2 in the region of a shared epitope with Alzheimer neurofibrillary tangles.

A 3.3-kilobase DNA complementary to human microtubule-associated protein 2 (MAP2) was sequenced by the dideoxy method. The 3' end terminates at an internal EcoRI site before the polyA tail. Due to the arrangement of the cDNA insert in the lambda gt11 vector, the MAP2 fragment is not fused to beta-galactosidase when expressed. The Chou Fasman algorithm for the initial 58 amino acids from the first in-frame methionine predicts an alpha helix. Beyond this point, a series of turns is predicted until amino acid 160. The frequent presence of basic residues in proximity to serines or threonines is consistent with multiple phosphorylation sites. The minimum specificity determinant for Ca2+/calmodulin-dependent kinase is repeated 13 times. The sequence of a region containing a MAP2 epitope that is shared with the Alzheimer neurofibrillary tangle was determined by DNase treatment of the cDNA and antibody selecting the small resultant clones in a lambda gt11 sublibrary. Likewise, a MAP2 epitope that is not shared with the neurofibrillary tangle also has been located. Both epitopes are in the projection portion of the molecule. A bovine MAP2 cyanogen bromide fragment, which contains the epitope shared with the neurofibrillary tangle, is partially insoluble under aqueous conditions, probably due to the aggregation of oppositely charged residues. Thus, rapid cleavage of MAP2 to small peptides is probably necessary in vivo to prevent the aggregation of larger cleavage fragments.

Alzheimer Disease↗
PubMed1987

Berry aneurysms, cirrhosis, pulmonary emphysema, and bilateral symmetrical cerebral calcifications: a new syndrome.

Familial idiopathic nonarteriosclerotic cerebral calcification (FINCC) constitutes a rare but pathologically well defined disorder. Thus far, central nervous system symptoms and signs have been the only recorded expression of this disease. Autosomal dominant and autosomal recessive inheritance have both been postulated as cause. We describe three sibs who had symmetrical cerebral calcifications, but three also had cirrhosis and pulmonary emphysema; two had congenital cerebral aneurysms. All were male and of short stature; they also had delayed development and seizures, and two had other neurologic deficits. One sib died at age 3 years of hepatic failure and portal hypertension. Ruptured cerebral aneurysms led to the death of the other two boys at ages 8 and 13 years. The cerebral calcifications symmetrically involved the basal ganglia and thalami, the dentate nucleus, and the cortical and subcortical areas of the cerebrum. The liver was studied by sequential biopsies in two of the children and in all three by autopsy. Fatty degeneration and portal fibrosis preceded a periportal and micronodular cirrhosis. Severe bilateral pulmonary emphysema was present in one sib at age 12 years, whereas all three had bullae and cysts at autopsy. Ruptured left middle cerebral artery aneurysms were demonstrated in two sibs, and one also had aneurysms of the anterior and posterior communicating arteries. We conclude that in this family FINCC is a complex pleiotropic mendelian mutation, either of autosomal or X-linked recessive nature, whose basic pathogenesis remains unknown but may involve a metabolic defect. This form of FINCC may be a previously undescribed syndrome or a form of FINCC in which extraneural manifestations were previously overlooked.

Adolescent↗
PubMed1985

Sulfasalazine and renal tubular function: lack of an effect.

Sulfasalazine (SASP) is frequently used in the treatment of chronic inflammatory bowel disease (IBD), particularly colitis. Because the drug poses a theoretical risk for renal tubular damage, 26 patients, 8-18 years of age, with Crohn's ileocolitis were studied. Thirteen children were receiving SASP while 13 served as disease controls. Renal tubular function was assessed by measurement of urinary beta 2-microglobulin and n-acetylglucosaminidase activity. No abnormalities were found on routine measurement of renal function. Similarly, urinary beta 2-microglobulin and n-acetylglucosaminidase activities were within normal limits for patients receiving SASP, as well as for disease controls. Although there is a theoretical risk for renal tubular damage from the prolonged use of SASP, this study would suggest that IBD patients receiving the drug are at no greater risk for renal injury than their counterparts not receiving the medication.

Adolescent↗
PubMed1985

Ethanol and fetal nutrition: effect of chronic ethanol exposure on rat placental growth and membrane-associated folic acid receptor binding activity.

Rat placental composition and specific folate receptor activity were measured at 20 days gestation in dams exposed to chronic high doses of ethanol (6%, vol/vol) throughout gestation and in isocalorically pair-fed controls. Ethanol-exposed fetuses were smaller (ethanol = 3.28 +/- 0.08 vs. control = 4.01 +/- 0.10 g, p less than 0.001), but their placentae were larger (experimental = 0.534 +/- 0.02 vs. control = 0.399 +/- 0.01 g, p less than 0.001). The increased weight appears to be secondary to hyperplasia as total DNA was increased while the wet/dry, RNA/DNA, and protein/DNA ratios were not different. Despite larger placentae, specific folate receptor activity was significantly reduced in the ethanol-exposed tissue, whether expressed relative to membrane protein, placental weight, or total placental binding. These results confirm that ethanol exposure is placentotoxic and suggest an additional mechanism by which ethanol may lead to intrauterine growth retardation; namely, decreased folate receptor activity.

Animals↗
PubMed1984

Histamine-releasing activity. V. Characterization and purification using high-performance liquid chromatography.

The production of large quantities of the lymphokine(s) histamine-releasing activity (HRA) and its partial purification by Sephadex G-75 and ion-exchange chromatography on carboxymethyl (CM) Sepharose 6B have been detailed (M. A. Lett-Brown, D. O. Thueson, D. E. Plank, M. P. Langford, and J. A. Grant, Cell. Immunol. 87, 434-444, 1984). Two peaks of activity (HRA I and II) were recovered. Preparations of HRA have now been analyzed by high-performance liquid chromatography (HPLC). Thoracic duct lymphocytes stimulated with 200 U/ml streptokinase were used as a source of HRA. Gel-filtration HPLC on a TSK 3000 column separated HRA into two peaks of activity (10,000-20,000 and 1300 Da). Reverse-phase high-performance liquid chromatography using a Nucleosil C-8 column showed that HRA II (the activity eluted at a conductivity of 18-20 mmho on the CM-Sepharose column) eluted as a single sharp peak, the main protein contaminant being cytochrome c, the carrier protein added to enhance the yield of HRA. High-performance liquid chromatography was found to be a useful analytical tool and may be suitable for the large-scale purification of HRA.

Chromatography, Gel↗
PubMed1981

Conversion to intermittent self-catheterization simplified.

Patients with indwelling catheters often resist conversion to intermittent self-catheterization because they fear urine leakage between catheterizations. We have taught our male patients to catheterize themselves through the lumen of an external condom catheter, which they wear until they achieve continence and feel safe with the new method. We herein report on the effectiveness of this approach to conversion to self-catheterization.

Humans↗
PubMed1980

Primary structure of elongation factor Tu from Escherichia coli.

The amino acid sequence of elongation factor Tu (EF-Tu) from Escherichia coli has been determined. EF-Tu is a single-chain polypeptide composed of 393 amino acids (Mr 43,225 for the species bearing COOH-terminal serine). The NH2-terminal serine is acetylated, and lysine-56 is partially methylated. The sites of facile tryptic cleavage are at arginines 44 and 58 and at lysine-263. The cysteinyl residues associated with aminoacyl-tRNA and guanosine nucleotide binding activities are residues 81 and 137, respectively. The COOH-terminal amino acid is heterogenous in that analyses of the COOH-terminal peptides isolated from different EF-Tu preparations gave position 393 as glycine and serine in ratios (Gly/Ser) ranging from about 0.7 to 3.

Amino Acid Sequence↗
PubMedDate not supplied

Nonsyndromatic paucity of interlobular bile ducts: light and electron microscopic evaluation of sequential liver biopsies in early childhood.

Liver biopsies and/or autopsy specimens from 17 children (ages 1 week to 5 years) with nonsyndromatic paucity of the interlobular bile ducts were studied by light and electron microscopy. Initial biopsies were obtained before 90 days of age from all patients, and two or more specimens were available from nine. No specific underlying condition was found in nine infants. The remaining cases were associated with Down's syndrome (n = 2), hypopituitarism (n = 2), cystic fibrosis (n = 1), alpha 1-antitrypsin deficiency (n = 1), cytomegalovirus (n = 1) and Ivemark syndrome (n = 1). Before 90 days of age, portal changes included duct paucity and fibrosis. Lobular changes were nonspecific, consisting of cholestasis, giant cell transformation, extramedullary hematopoiesis and perisinusoidal fibrosis. Duct paucity, portal fibrosis and perisinusoidal fibrosis persisted after 90 days. Cholestasis was mild or no longer apparent. Portal changes before 90 days of age appear to be sufficiently distinctive to microscopically distinguish nonsyndromatic from syndromatic paucity. Electron microscopic findings suggest that paucity in nonsyndromatic patients may result from a primary ductal insult: ultrastructural studies revealed bile duct destruction characterized by undulation and breaks in the basal lamina and infiltration of the epithelium by lymphocytes. Bile canalicular dilatation with blunting of microvilli and electron-dense material in the lumen, predominantly seen before 90 days, also reinforces the hypothesis of a primary ductal defect.

Age Factors↗
PubMedDate not supplied

Can group- and serovar-specific proteins be detected in Ureaplasma urealyticum?

Ureaplasma urealyticum has been subspeciated by a number of serologic methods. Eight serotypes have been identified by modified metabolic inhibition, growth inhibition and indirect hemagglutination. Fourteen serovars have been identified by immunofluorescence and 16 by the mycoplasmacidal assay. The present studies were performed to determine if group-specific antigens could be detected by immunofluorescence and if group- or serovar-specific antigens could be detected by enzyme-linked immunosorbent assay and immunoblotting. Reaction of rabbit antisera to U. urealyticum with homologous and heterologous serotypes based upon end point immunofluorescent titration did not differentiate the serovars into the two biotypes. In attempts to quantitate the number of a given serovar present in clinical specimens, the total number of colonies that were stained often exceeded 100%, suggesting either that the serovars represented in stock cultures are not truly representative of those present in humans or that certain strains express multiple serovar specificities. End point titration in an enzyme-linked immunoadsorbent assay using either whole cells or cell lysates and rabbit antisera failed to distinguish between group and serovars (i.e. in many cases end point titers were only 2-fold lower with heterologous antigens). Furthermore convalescent sera from patients infected with a single serovar failed to induce a serovar-specific response detectable in an enzyme-linked immunosorbent assay. Likewise immunoblotting of one dimensional electrophoretograms with sera from humans known to be infected with a single serovar showed that antibodies against that serovar recognized peptides present in all serovars and reacted with those bands with various degrees of intensity.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Bacterial↗
PubMedDate not supplied

Selective fetal malnutrition: effect of acute and chronic ethanol exposure upon rat placental Na,K-ATPase activity.

Intrauterine growth retardation (IUGR) is characteristic of the fetal alcohol syndrome (FAS). This IUGR is partly due to the toxic effect of ethanol upon placental function, including amino acid transport. Amino acid transport is dependent, in part, upon Na,K-ATPase; therefore, plasma membrane activity of Na,K-ATPase was measured in rat placentas following acute or chronic ethanol exposure. Acute (A) animals were chow fed and gavaged with ethanol on day 20 of gestation and killed 2 hr later; controls (A-C) received sucrose. Binge (B) animals were gavaged on gestation days 18 and 19; controls (B-C) received sucrose. Chronic animals were fed ethanol in a liquid diet containing 2% (CHR-2%) or 6% (CHR-6%) ethanol by volume and killed on day 20. Controls (CHR-2%-C or CHR-6%-C) were isocalorically pair fed. Maternal blood ethanol levels were 197.1 +/- 29.7 mg/dl (mean +/- SE) for A dams and 128.2 +/- 15.2 for B (drawn at time of death); 12.6 +/- 2.2 for CHR-2% and 195.0 +/- 26.0 for CHR-6% (drawn weekly and at time of death). Placental weight was increased and fetal weight decreased in the CHR-6% animals. A, B, and CHR-2% placental and fetal weights were unaffected. Na,K-ATPase specific activity was increased in B placentas: B = 134.7 +/- 16.5 versus B-C = 50.0 +/- 7.4 nmol of Pi/mg of protein/min (p less than 0.01). Conversely, CHR-6% treatment diminished enzyme activity: CHR-6% = 37.0 +/- 4.5 versus CHR-6%-C = 58.5 +/- 4.4 (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗