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Biomedical subjects

R C Johnson

Publications and source records attributed to R C Johnson.

At least 163 records · Page 9Linked to original sources
PubMed1994

Serologic surveillance for the Lyme disease spirochete, Borrelia burgdorferi, in Minnesota by using white-tailed deer as sentinel animals.

To determine the effectiveness of white-tailed deer as sentinel animals in serologic surveillance programs for Borrelia burgdorferi, we performed enzyme-linked immunosorbent assay (ELISA) and Western immunoblotting analyses on 467 deer serum samples. The seropositivity rate in the ELISA was 5% for the 150 samples collected at the three sites in which the tick Ixodes scapularis was absent. The three sites with established I. scapularis populations had a seropositivity rate of 80% for 317 samples. Results were similar for two closely situated sites, one with an established I. scapularis population and one without; these sites were only 15 km apart. Rates of seropositivity were significantly higher in yearling and adult deer than in fawns. The mean numbers of bands seen on Western immunoblots were 3.0 for samples negative in the ELISA and 13.8 for samples positive in the ELISA; all of these samples were collected from sites in which I. scapularis was established. At sites in which I. scapularis was absent, the mean numbers of bands seen were 1.6 for samples negative in the ELISA and 8.2 for samples positive in the ELISA. There were 14 different B. burgdorferi antigens that reacted with more than 50% of the ELISA-positive samples from areas with I. scapularis. A 19.5-kDa antigen reacted with 94% of the ELISA-positive samples. Reactivity against OspA and OspB was weak a infrequent (2%). Serologic analysis of white-tailed deer sera appears to be an accurate and sensitive surveillance method for determining whether B. burgdorferi is present in specific geographic locations.

Animals↗
PubMed1994

Comparison of different strains of Borrelia burgdorferi sensu lato used as antigens in enzyme-linked immunosorbent assays.

Eight strains of Borrelia burgdorferi sensu lato were tested with serum samples from persons who had Lyme borreliosis or syphilis in class-specific enzyme-linked immunosorbent assays (ELISAs). Antigens of B. burgdorferi sensu stricto, of Borrelia garinii, and of Borrelia spirochetes in group VS461 were prepared from cultured bacteria isolated from ticks, a white-footed mouse (Peromyscus leucopus), or human tissues in North America, the former Soviet Union, and Japan. Nearly all of the serum specimens that contained immunoglobulins to strain 2591, a Connecticut isolate, were also positive in antibody tests with the other seven strains. In general, all eight strains reacted similarly and were suitable as coating antigens in class-specific ELISAs. Assay sensitivities ranged from 82.6 to 100% in analyses for immunoglobulin M and G antibodies. Compared with reference antigen strain 2591, strains 231 (a tick isolate from Canada) and NCH-1 (a human skin isolate from Wisconsin) resulted in higher antibody titers in an ELISA. Syphilitic sera cross-reacted in all tests regardless of the antigen used. Key immunodominant proteins are shared among the closely related strains of B. burgdorferi sensu lato tested, but it is suspected that variations in antigen compositions among these spirochetes may sometimes affect assay performance for detecting serum antibodies.

Animals↗
PubMed1994

PACE4: a subtilisin-like endoprotease prevalent in the anterior pituitary and regulated by thyroid status.

Low stringency screening of a rat hypothalamic complementary DNA library for additional members of the subtilisin-like prohormone convertase (PC) family identified rat PACE4, which is 90% identical to human PACE4 in amino acid sequence, with much lower similarity to rat PC1, PC2, furin, PC4, or PC6. The rat PACE4 sequence has the Asp-His-Ser catalytic site triad, an Arg-Gly-Asp potential integrin binding site, and three potential sites for N-linked glycosylation. Rat PACE4 has a long COOH-terminal region, which is very rich in Cys residues (15%). The unique signal sequence of rat PACE4 mediates translocation across microsomal membranes during in vitro translation and secretion of PACE4 from stably transfected fibroblast cells. Rat PACE4 has a tissue and cell line distribution unlike any reported PC, including human PACE4, with high expression in the anterior pituitary and readily detectable expression in several brain regions, the atrium, and the ventricle; negligible PACE4 messenger RNA (mRNA) is detected in neurointermediate pituitary and many nonneuroendocrine tissues. PACE4 mRNA is prevalent in Buffalo rat liver and GH3 cells and present at low levels in AtT-20 cells, whereas it is undetectable in several other cell lines. In situ hybridization coupled with immunocytochemistry revealed that PACE4 is produced by somatotropes, mammotropes, and corticotropes, whereas less PACE4 mRNA was detected in thyrotropes. PACE4 mRNA levels in anterior pituitary are strikingly regulated by thyroid status, with more than a 10-fold increase seen from hypothyroid to hyperthyroid animals. The prevalence of PACE4 in anterior pituitary and the striking effect of thyroid status on PACE4 expression suggest a specific role for PACE4 in processing neuroendocrine peptides.

Amino Acid Sequence↗
PubMed1994

Alcohol consumption and use norms among Chinese Americans and Korean Americans.

Homeland (Taiwan) Chinese are very low in alcohol consumption, while homeland Koreans are very high in alcohol consumption. Neither Chinese Americans nor Korean Americans constitute a large portion of the residents of Hawaii, but across four surveys, data were obtained from 212 Chinese-American and 72 Korean-American college students or students' parents. Persons from these groups do not differ greatly. Korean Americans are slightly higher in reported alcohol use and in judgments of the nature of normal alcohol use. The two groups do not differ in their judgments of the nature of problem alcohol use.

Adult↗
PubMed1994

Molecular basis of human band-3 mutation associated with increased anion transport.

Band 3, the anion transporter, is a ubiquitous protein. It is present in brain and all other tissues. Not only is band 3 present in cell membranes, but also in nuclear, Golgi, and mitochondrion membranes. Band 3 is involved in respiration, acid-base balance, and is the major structural protein linking the plasma membrane to the cytoskeleton. Thus, alterations/mutations in the transport segment of the band-3 molecule might be expected to be of major importance. We discovered and sequenced a mutation of band 3, high-transport band 3 (HTbd3), that exhibits anion transport that is 2-3 time above normal. Anion transport studies of the family members revealed that red cells from the proposita, one of two siblings, and both parents had abnormally increased anion transport (increased Vmax). We used synthetic peptides of band 3 to help localize the change along the band-3 molecule. Results suggest that high-transport band 3 is altered in or near residue 869-883. This places the alteration toward the carboxyl terminal of band 3. cDNA sequencing demonstrated that the mutation was a proline to leucine at residue 868. A peptide was synthesized corresponding to residues 853-870 for testing in the anion transport inhibition assay. This peptide significantly inhibited anion transport (p < or = 0.001) indicating that it is an anion transport/binding region of band 3. Thus, DNA technology confirms the validity of the anion transport inhibition assay for localizing transport regions. Glucose transport is decreased in affected individuals. The HTbd3 mutation appears benign as determined by the red cell aging panel. IgG binding, creatinine, and glyceraldehyde-3-phosphate dehydrogenase are normal. Our studies indicate that the most rapid and sensitive techniques for detecting band-3 alterations are polyacrylamide gel electrophoresis, IgG binding, and anion transport studies. This is the only mutation of band 3 discovered to date the affects the transmembrane, anion transport region of band 3.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1994

Family-centered care: thriving in Hawaii under Part H.

Hawaii's system of prevention and early intervention embodies Part H principles that a child with a disability is first surrounded by a family, then by a community. Since 1986, families in Hawaii have been active in early intervention, first by persuading the governor to name the Department of Health as the lead agency, and then by writing much of the original grant application, interviewing and selecting staff members, and serving on the Hawaii Early Intervention Coordinating Council and its subcommittees. Families helped develop Hawaii's broad definition of the population to be served and were vocal advocates before the legislature to obtain funding for the program. Under Part H, Hawaii serves 6% of all children under the age of three, a larger percentage than any other state. Services focus on the family's needs as much as on the child's. The Individualized Family Support Plan (IFSP), developed jointly by the parents and professionals, recognizes families as the final decision-maker on the IFSP team. Families choose options that fit their needs. IFSP meetings are at times and places convenient to families and, to the extent feasible, in the family's native language. Care coordinators, of whom several are parents of children with special needs, monitor services to ensure that families receive quality care. Families receive (1) services at no cost, (2) preference when applying for positions in the Zero-to-Three Hawaii Project, and (3) compensation when serving in advisory or policy-making areas. In Hawaii, families are the center of early intervention services.

Audiology↗
PubMed1994

New York University Dental Center Library. Preparing to meet the information needs of the dental team today and in the 21st century.

The introduction of new computer technology has been changing the way libraries provide access to the vast amount of information being produced in the fields of medicine and dentistry. The NYU Dental Library is responding to the challenge with new systems that improve its daily operation and expand users' abilities to gain access to the data they need.

Computer Communication Networks↗
PubMed1994

High levels of expression of the tumor suppressor gene APC during development of the rat central nervous system.

The adenomatous polyposis coli (APC) gene is a tumor suppressor gene that is mutated in human familial adenomatous polyposis, an autosomal dominant condition with predisposition to colorectal carcinoma and brain tumors. Although tumor suppressor genes appear to play a general role in regulating cellular proliferation, the normal biological function of the APC gene product is unknown. In the present study, we cloned fragments of the rat homolog of the APC gene and examined its tissue distribution by Northern blot analysis. These studies demonstrated particularly high levels of APC mRNA in brain. To gain clues to the role of the APC gene in brain function, we examined the neuroanatomical distribution of APC mRNA using in situ hybridization. In the adult, prominent expression of APC mRNA was observed in the olfactory bulb, hippocampus, and cerebellum, with low levels of hybridization in other regions of adult rat brain. In contrast, during embryonic and early postnatal development (1-2 weeks), high levels of APC expression were found throughout the brain and then decreased to adult levels by 6 weeks after birth, except in the olfactory bulb where the high levels of APC mRNA found in development persist in the adult. During development of cortex, cerebellum, and retina, APC mRNA expression was particularly prominent in layers containing newly formed postmitotic neurons, with lower levels observed in the proliferative zones where neurogenesis occurs. The high levels of APC expression from early neurogenesis until late stages of neuronal maturation suggest that APC may contribute to suppressing neuronal proliferation during this period of intense growth.

Adenomatous Polyposis Coli↗
PubMed1993

Isolation of Leptospira interrogans serovar grippotyphosa from the skin of a dog.

Leptospira interrogans serovar grippotyphosa was isolated from the skin of a 14-year-old male dog with deteriorating health. Necropsy revealed numerous lesions characteristic of aged dogs, but no evidence of acute hepatitis or nephritis, which are common features of pathogenic Leptospira infections. Antibody to Leptospira was not detected in the dog's serum by microagglutination. Leptospires grew slowly in Barbour-Stoenner-Kelly medium, a medium commonly used to isolate Borrelia, but then grew abundantly in Tween 80-bovine albumin leptospire medium. The isolate was pathogenic to a hamster and was identified by microagglutination and restriction endonuclease analysis.

Animals↗
PubMed1993

Leukocyte rolling and extravasation are severely compromised in P selectin-deficient mice.

P selectin, expressed on surfaces of activated endothelial cells and platelets, is an adhesion receptor for leukocytes. We report that P selectin-deficient mice, generated by gene targeting in embryonic stem cells, exhibit a number of defects in leukocyte behavior, including elevated numbers of circulating neutrophils, virtually total absence of leukocyte rolling in mesenteric venules, and delayed recruitment of neutrophils to the peritoneal cavity upon experimentally induced inflammation. These results clearly demonstrate a role for P selectin in leukocyte interactions with the vessel wall and in the early steps of leukocyte recruitment at sites of inflammation. These mutant mice should prove useful in deciphering the contributions of P selectin in various inflammatory responses as well as in platelet functions.

Alleles↗
PubMed1993

Crystallization and preliminary X-ray analysis of the DNA binding domain of the Hin recombinase with its DNA binding site.

The Hin recombinase catalyzes site-specific inversion of DNA. Chemical and genetic studies on Hin binding to the recombination sites indicates that both major and minor DNA groove interactions are critical. In order to determine the molecular nature of these interactions, we have crystallized a synthetically derived 52 amino acid peptide consisting of the DNA binding domain of Hin with a 14 base-pair oligonucleotide representing a recombination half-site. This communication presents preliminary diffraction and analysis of these cocrystals and a packing model for the complex within the crystal.

Amino Acid Sequence↗
PubMed1993

Topological switching of the COOH-terminal domain of peptidylglycine alpha-amidating monooxygenase by alternative RNA splicing.

Proteins encompassing the two catalytic domains (monooxygenase and lyase) and the COOH-terminal domain of rat peptidylglycine alpha-amidating monooxygenase (rPAM)3 were purified from recombinant Escherichia coli overexpressing each domain and used to raise domain-specific polyclonal antibodies. Four alternatively spliced forms of PAM RNA (PAM-1, -2, -3, and -4) were transcribed in vitro and used to synthesize PAM proteins in a cell-free translation system. The orientation of the proteins in microsomal membrane vesicles was analyzed using trypsin protection assays and immunoprecipitation with the domain-specific antibodies. Only one of the two potential N-glycosylation sites (Asn765-Phe-Ser) in PAM-1 was efficiently utilized by microsomal membranes. PAM-1 and PAM-2 were shown to be type Ia membrane proteins with their two catalytic domains residing within microsomal vesicles and their COOH-terminal domains exposed to the cytosol. In contrast, PAM-3 and PAM-4 were shown to be soluble proteins contained entirely within vesicles. Thus, the COOH-terminal domain underwent topological switching between the cytosolic (PAM-1 and -2) and luminal (PAM-3) compartments as a function of alternative splicing of exons Ba/Bb. Computer analyses of the PAM protein sequence correlated the exons encoding PAM-1 with a model for the structural and functional domains of the PAM protein. The dual topologies of the PAM proteins confer an important means of functional regulation to this secretory granule associated neuropeptide processing enzyme.

Amino Acid Sequence↗
PubMed1993

DNA looping and the helical repeat in vitro and in vivo: effect of HU protein and enhancer location on Hin invertasome assembly.

Site-specific DNA inversion by the Hin recombinase requires the formation of a multicomponent nucleo-protein structure called an invertasome. In this structure, the two recombination sites bound by Hin are assembled together at the Fis-bound recombinational enhancer with the requisite looping of the intervening DNA segments. We have analyzed the role of the HU protein in invertasome assembly when the enhancer is located at variable positions close to one of the recombination sites. In the absence of HU in vitro and in hupA hupB mutant cells in vivo, invertasome assembly is very inefficient when there is < 104 bp of DNA between the enhancer and recombination site. Invertasome assembly in the presence of HU in vitro or in vivo displayed a periodicity beginning with 60 bp of intervening DNA that reflected its helical repeat. The average helical repeat for this DNA region was calculated by autocorrelation and Fourier transformation to be 11.2 bp per turn for supercoiled DNA both in the presence of HU in vitro and in hup+ cells in vivo. HU is the only protein in Escherichia coli that can promote invertasome formation with short DNA lengths between the enhancer and recombination sites. However, the presence of certain polyamines and a protein activity present in HeLa nuclear extracts can efficiently substitute for HU in invertasome assembly. These data support a model in which HU binds non-specifically to the DNA between the enhancer and recombination site to facilitate DNA looping.

Bacterial Proteins↗
PubMed1993

Familial transmission of cognitive abilities in offspring tested in adolescence and adulthood: a longitudinal study.

As part of a follow-up study of now-adult offspring who originally participated in the Hawaii Family Study of Cognition (HFSC) from 1972 to 1976, 49 females and 46 males from 73 families of Caucasian ancestry and 63 females and 55 males from 92 families of Japanese ancestry were retested (average test-retest interval, 13 years) on the battery of cognitive abilities tests they took as adolescents. Age-corrected scale scores for verbal ability, spatial ability, perceptual speed, visual memory, and unrotated first principal component were calculated for the offspring's fathers and mothers, for their original HFSC testing, and for the retesting. Model-fitting procedures for a univariate model of familial transmission indicated significant differences in the parameters between the two racial/ethnic groups for all five cognitive abilities scales. These procedures also demonstrated no significant differences in familialities for offspring abilities in adolescence vs. mature adulthood across all five abilities scales and both racial/ethnic groups.

Adolescent↗
PubMed1993

Family background, cognitive abilities, and personality as predictors of education and occupational attainment across two generations.

This study reports on the relative influences of parental attainment and cognitive ability and subjects' own cognitive ability, personality, and social attitudes on the educational and occupational attainments and incomes of 183 Generation 3 subjects of Caucasian ancestry and 186 of Japanese ancestry originally tested in 1972-76 in the Hawaii Family Study of Cognition (HFSC) and re-tested in 1987-88. In contrast to earlier reports of sex differences in the influence of Generation 2 attainment and on Generation 3 attainment when these offspring were younger, family background had a trivial influence and own cognitive ability had a substantial influence on educational attainment for both racial/ethnic groups and both sexes. For income, however, own cognitive ability was only a significant predictor for male subjects. Within-family correlational analyses also supported this sex difference in influences on attainment.

Adult↗