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Biomedical subjects

M Arens

Publications and source records attributed to M Arens.

At least 37 records · Page 2Linked to original sources
PubMed1993

Evolution of sequence divergence among human immunodeficiency virus type 1 isolates derived from a blood donor and a recipient.

Four neonates who were infected with a single unit of blood from a human immunodeficiency virus-1 (HIV-1)-infected adult (patient 1) were studied. Two of the infected children (patients II and III) developed symptomatic HIV-1 disease and died within the first 3 y of life. One child (patient IV) died at 8 mo of age of clinical problems that may have been HIV-related. In contrast, one child (patient V) has remained asymptomatic for 7.5 y and has exhibited a very gradual decline in CD4+ cell number. A previous study had shown very limited sequence diversity of isolates from patients I, II, and III (McNearney T et al.: Proc Natl Acad Sci USA 87:1917-1921, 1990). The current study examined additional HIV-1 sequences encoding the principal neutralizing V3 loop of the surface envelope protein of isolates from patients I and V. Amplified sequences were obtained using the polymerase chain reaction from a cultured isolate and uncultured peripheral blood leukocytes, and nucleotide sequences were determined for 13 clones from patient I and 19 clones from patient V. Clones derived from the cultured isolate exhibited less predicted amino acid sequence diversity on average (0-5.2%) than did sequences from uncultured leukocytes (0-19.8% differences). All clones were more closely related to those from patients II and III (0-19.8% amino acid differences) than to other North American or European isolates (18.8-27.0% amino acid differences) or African isolates (41.0-48.0% amino acid differences). Substitutions occurred at sites predicted to modulate host cell tropism and proteolytic cleavage of the V3 loop.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Cross-contamination potential with dental equipment.

Some types of reused dental equipment, especially handpieces and their attachments for drilling and cleaning teeth, might be responsible for cross-contamination if patient material were to lodge temporarily in difficult-to-disinfect internal mechanisms. This possibility is worrisome with respect to transmission of hepatitis B and human immunodeficiency viruses (HBV, HIV). Previous cross-contamination studies have relied on laboratory experiments with bacteria or dye tracers. To assess possible risk more thoroughly, we tested 30 new prophylaxis angles and 12 new high-speed handpieces to see whether they would take up and expel contaminants in laboratory and clinical trials. In treatments of three patients, including two infected with HIV, human-specific DNA (beta-globin, HLA DQ alpha) and HIV proviral DNA were detected inside or coming back from the devices. Similarly, when handpieces were operated in contact with blood pooled from HBV-infected patients, HBV DNA was detected in samples taken from inside the equipment and from their attached air/water hoses. When we used bacteriophage phi X174 as a model virus in laboratory tests, many infective viral particles were recovered from internal mechanisms of handpieces, their connecting air/water hoses, and from water spray expelled when the equipment was reused. We recommend that reused high-speed, air-driven handpieces and prophylaxis angles should be cleaned and heat-treated between patients. Further studies are needed to determine ways of eliminating the risks associated with exhaust hoses and air/water input lines.

Bacteriophages↗
PubMed1992

Relationship of human immunodeficiency virus type 1 sequence heterogeneity to stage of disease.

V3 envelope sequences were determined from amplified human immunodeficiency virus type 1 (HIV-1) sequences of uncultivated leukocytes obtained sequentially from four infected adults over the course of infection. Lower levels of sequence heterogeneity were noted in samples obtained early in HIV-1 infection, prior to CD4 depletion, than in samples obtained at later times during disease. The pattern of amino acid sequence divergence included nonrandom changes, with evidence of sequence variants arising from HIV-1 quasi-species present earlier in infection. Consensus sequences for isolates obtained early after infection from different patients demonstrated a high level of conservation with one another and a consensus sequence for macrophage-tropic HIV-1 isolates. These findings suggest that a highly restricted subset of HIV-1 quasi-species can be transmitted and can establish infection.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Platelet-targeted fibrinolysis enhances clot lysis and inhibits platelet aggregation.

BACKGROUND: Although plasminogen activator therapy has been shown to reduce mortality in patients with severe myocardial infarction, several problems fuel the search for more potent and specific thrombolytic agents. METHODS AND RESULTS: To explore the effect of plasminogen activator targeting to platelets, we covalently linked urokinase that had been modified with N-succinimidyl-3-(2-pyridyldithio)propionate to the Fab' of a monoclonal antibody (7E3) that selectively binds to platelet membrane glycoprotein (GP) IIb/IIIa. In an assay measuring (as reflected by plasmin generation) a plasminogen activator's ability to bind GP IIb/IIIa immobilized on plastic, urokinase-7E3 Fab' produced 31-fold more plasmin than did urokinase (p = 0.0001). The addition of solubilized GP IIb/IIIa blocked this enhancement of plasmin generation, indicating that binding was impaired. Plasmin generation reflecting binding to immobilized intact platelets was 2.4-fold greater for urokinase-7E3 Fab' than for unconjugated urokinase (p = 0.002). In a plasma clot lysis assay, urokinase-7E3 Fab' was at least 25-fold more potent than either urokinase alone or a mixture of urokinase and 7E3 (Fab')2 (p less than 0.009), and potency could be related to platelet concentration in the clot. Ex vivo, ADP-induced platelet aggregation was inhibited by a urokinase-7E3 IgG conjugate at a concentration of 8 nM, whereas a mixture of urokinase and 7E3 (Fab')2 in equimolar amounts required 60 nM and urokinase alone required 1 microM to achieve the same effect. CONCLUSIONS: Therefore, the targeting of urokinase to the GP IIb/IIIa platelet receptor both accelerates clot lysis (when platelets are associated with a fibrin clot) and inhibits platelet aggregation.

Antigens↗
PubMed1990

Evaluation of the safety and efficacy of amrinone in chronic obstructive lung disease with cor pulmonale.

In a pilot study the effect of a bolus dose of amrinone intravenously (IV), 0.5 or 1 mg/kg body weight, in 10 patients with chronic obstructive lung disease and cor pulmonale was evaluated. We found that the higher dose of 1.0 mg/kg IV significantly (P less than 0.05) decreased the mean pulmonary artery pressure and pulmonary wedge pressure without significant changes in cardiac output, in systemic blood pressure or in arterial blood gas values. No adverse effects were recorded in any of the patients.

Aged↗
PubMed1989

Detection of rotavirus by hybridization with a nonradioactive synthetic DNA probe and comparison with commercial enzyme immunoassays and silver-stained polyacrylamide gels.

Three enzyme-linked immunosorbent assays (ELISAs) (rotavirus enzyme immunoassay [EIA; International Diagnostic Laboratories], Pathfinder [Kallestad Laboratories], and Rotaclone [Cambridge Bioscience, Inc.]) and hybridization of viral RNA with a nonradioactive, synthetic oligonucleotide DNA probe (SNAP; Molecular Biosystems, Inc.) were compared with silver-stained polyacrylamide gel electrophoresis (PAGE) of viral RNA for the detection of rotavirus in fecal specimens. Hybridization was performed following column purification of the viral RNA. Of 286 specimens analyzed by PAGE, SNAP, rotavirus EIA, Pathfinder, and Rotaclone, 88 were positive by PAGE. All 88 specimens were also positive by the other four assays. Nine specimens that were positive by one or more of the assays were positive by blocking ELISAs but were negative by PAGE. If these nine specimens were considered to be true positives, the final sensitivities and specificities were as follows: PAGE, 91 and 100%; SNAP, 94 and 97%; rotavirus EIA, 96 and 97%; Pathfinder, 100 and 94%; and Rotaclone, 96 and 97%, respectively.

DNA Probes↗
PubMed1988

Effects of sonication and centrifugation of clinical specimens on the recovery of herpes simplex virus.

We have analyzed frozen and fresh specimens for herpes simplex virus (HSV) to determine the effect of sonication and centrifugation on virus recovery. After sonication, titers of 24/27 specimens increased from 1.3-30.8-fold with a mean increase of 6.8-fold. One hundred seventy-four fresh specimens were inoculated before and after sonication into CV-1 tube cultures. There was not a statistically significant difference in time to positivity between the sonicated and unsonicated portions. Thus, although sonication of specimens can sharply increase the viral titer of positive specimens, sonication of fresh specimens does not significantly enhance the isolation of HSV. To determine the effect of centrifugation of clinical specimens on recovery of HSV, thirty-one culture positive frozen specimens were centrifuged, and the supernatants and resuspended sonicated pellets were titered. Twenty-five specimens had sufficient recoverable virus to titer; in 21/25 (87.5%) specimens the titers were reduced in the supernatants after centrifugation (mean reduction 38%; range of 4-92%). Two of 31 (7%) supernatants were negative in culture while the sonicated pellets were positive. Thus, centrifugation of specimens prior to cell inoculation may compromise recovery of HSV.

Animals↗
PubMed1988

Remarkably homogeneous population of adenovirus type 3 and 7 genome types.

A total of 270 frozen adenovirus isolates, obtained from January 1981 to December 1986, were grown in KB cells. DNA was successfully prepared from 248 of these isolates, and the prepared DNA was digested initially with SmaI restriction endonuclease and then analyzed by agarose gel electrophoresis. Restriction fragment patterns showed that 68 of these DNAs were either adenovirus type 3 (Ad3) or Ad7. Further analysis by digestion with BamHI showed that 24 isolates were Ad3a and 44 isolates were Ad7b. When Ad3 isolates were digested with SmaI or PstI, the restriction fragment patterns of the 24 isolates were identical. Of these 24 isolates, 20 (83%) also gave identical patterns when digested with HindIII, and the patterns of the remaining 4 isolates were different from that of the 20 but identical to each other. All Ad3 isolates were obtained in 1982, 1983, and 1986. All the 44 Ad7b isolates gave identical fragment patterns when digested with BglI or PvuII, and 43 of 44 (98%) isolates gave identical patterns when digested with SstII. We obtained at least two Ad7 isolates during each of the 6 years studied. Although considerable genome heterogeneity within adenovirus serotypes and subtypes has been reported, our population of isolates is remarkably homogeneous. This homogeneous set of genome types was obtained from diverse anatomical sites and was associated with a broad spectrum of clinical syndromes.

Adenoviruses, Human↗
PubMed1986

The development of the trigeminal (V) motor nucleus in normal and tubocurare treated chick embryos.

The generation of cells and the naturally occurring neuronal death was studied in the trigeminal motor neuron pool in normal and tubocurare treated chick embryos between the 5th and 18th days of incubation. 3H-thymidine autoradiography revealed that the generation time extends from the 2nd to the 5th day of incubation, wherein about 50% of trigeminal motoneurons are born on the 3rd day. Maximum neuron number was found on the 7th day of incubation which steadily decreased to about 50% of the originally generated neurons by the 13th day. Nuclear pyknosis occurred from the 6th to the 13th day of incubation with a peak of neuron loss on the 7th day. Tubocurare, administered daily from the 5th day of incubation rescued most of the generated motoneurons which would otherwise have died. Cell nuclear area measurements in the motoneuron pool of the tubocurare treated animals showed a marked hypertrophy accompanying the increased neuronal survival. These observations indicate that tubocurare treatment prevents naturally occurring neuron death and causes significant nuclear hypertrophy within the trigeminal motoneuron pool innervating special, branchial arch derived muscles. Thus these neurons respond to tubocurare treatment in a manner similar to motoneurons of the spinal cord.

Animals↗
PubMed1984

An outbreak of herpes simplex virus type I gingivostomatitis in a dental hygiene practice.

An outbreak of herpes simplex virus (HSV) type I gingivostomatitis occurred in a dental hygiene practice in November 1981. An epidemiologic investigation disclosed that 20 of 46 patients seen by the dental hygienist during a four-day period had this illness, whereas none of 26 patients seen by the dentist alone became ill. One day after the outbreak, the hygienist was found to have a herpetic whitlow. Identical endonuclease restriction enzyme type I HSV was isolated from the left index finger of the hygienist and from nine of 16 patients. The nine patients with positive cultures all had at least a fourfold increase in complement fixing antibody titer. A similar significant increase in titer indicated another seven cases.

Adolescent↗
PubMed1984

Characterization of hepatitis B virus DNA polymerase.

Hepatitis B virus (HBV) particles were separated from the blood-plasma containing HBe and HBs antigens (subtype adr) and the nature of the endogenous DNA polymerase in the HBV core particles was studied. The HBV endogenous DNA polymerase activity was examined under the conditions used for preparation of HBV vaccine. The endogenous DNA polymerase activity was reduced slowly upon the heat treatment or the formalin treatment. The reductions of the activity were 65% and 70% upon the heat treatment at 60 C for 10 hr and the formalin treatment at 37 C for 90 hr, respectively. Properties of the HBV endogenous DNA polymerase were studied by utilizing specific inhibitors against the eukaryotic DNA polymerases. Our results showed that the HBV endogenous DNA polymerase is resistant to aphidicolin and N-ethylmaleimide, and sensitive to 2',3'-dideoxythymidine 5'-triphosphate, phosphonoformic acid and 9-beta-D-arabinofuranosyladenosine 5'-triphosphate.

Aphidicolin↗
PubMed1983

Chlamydia trachomatis in 'abacterial' prostatitis: microbiological, cytological and serological studies.

Chlamydia trachomatis was isolated from urethral swabs after prostatic massage in patients with 'abacterial' prostatitis. After exclusion of prostatic infections by gram-negative bacteria, enterococci and ureaplasmas, in 20 of 43 patients with apparent monoinfection by C. trachomatis, a leucocytal reaction was demonstrated in prostatic secretions. By microimmunofluorescence test, antibody titers greater than or equal to 1:8 against various types of C. trachomatis were detected in these patients, whereas serology was negative in chlamydia-positive patients without increased leucocyte counts (prostatodynia).

Adolescent↗
PubMed1983

[Enzyme-linked immunosorbent assay (ELISA) for IgG- and IgM antibodies in chlamydial infections of humans].

The development and evaluation of an indirect ELISA for IgG and IgM antibodies in human sera against the genus-specific chlamydial antigen is described. Application of commercial anti-immunoglobulins for production of conjugates usually resulted in direct conjugate/antigen reactions. Therefore, all immunoreagents had to be prepared by the authors. Using anti-immunoglobulins purified by affinity chromatography for the production of anti-human IgG(H + L)-peroxidase conjugates, these conjugates showed high specific activity and could be diluted 1/10,000 for the test, whereby direct reactions with antigens were negligible (12 +/- 12 ELISA units). Results with the mu-chain-specific IgM ELISA could be verified additionally by rheumatoid factor analysis and gel-chromatographic investigations. Reactions with sodium deoxycholate extracted antigen from cells not infected with chlamydiae ("negative antigen") were observed with sera from persons working with cell cultures. In comparison with microimmunofluorescence (MIF) test and radioimmunoassay (RIA), the ELISA was the most sensitive method. However, for differentiation of urogenital infections associated with chlamydiae, the type-specific MIF test was superior to the genus-specific ELISA. In comparison to persons with chlamydia-associated prostatitis, the high percentage of IgM-positive reactions in patients with nongonococcal urethritis (10% and 56%, respectively) pointed to a predominant participation of genus-specific IgM antibodies in recent infections. As compared to ELISA values of patients with infections of the urogenital tract (up to 875 ELISA units), in some apparently healthy blood donors significantly higher ELISA values (up to 1400 ELISA units) were recorded. Such reactions may be attributed to systemic infections, e.g. chlamydial pneumonias. The importance to differentiate between IgG and IgM antibodies in such infections is discussed.

Antibodies, Bacterial↗
PubMed1983

Significance of Chlamydia trachomatis in "abacterial" prostatitis.

Chlamydia (C.) trachomatis was isolated in McCoy cell cultures from urethral swabs after prostatic massage, of 43 out of 233 patients (18.5%) with symptoms of "abacterial" prostatitis, but also from 5 out of 65 control persons (7.7%). Numbers of granulocytes in sediments of cytocentrifuged urine voided after prostatic massage were normal (less than or equal to 2, magn. 400 X) in all 65 control persons, but were increased in 26 out of 43 patients with symptoms of "abacterial" prostatitis (greater than or equal to 4, magn. 400 X). Using an (H + L) chain specific anti-IgG FITC conjugate, microimmunofluorescence tests for detection of antibodies against C. trachomatis could be performed with the sera of all 65 control persons and with those of 37 out of the 43 patients. All control persons, even those five with positive C. trachomatis culture, were serologically negative (titer less than 1:8), while in 13 out of 15 C. trachomatis positive patients with a definitive diagnosis of "abacterial" prostatitis, humoral antibodies with titers of greater than or equal to 1:8, predominantly against serotypes I, J, E, and G, were detected. Serological results correlated well with granulocyte counts in urines after prostatic massage. Patients with symptoms of "abacterial" prostatitis with normal granulocyte counts (less than or equal to 2) and negative serology (titer less than 1:8) were considered suffering from "prostatodynia".

Adolescent↗
PubMed1983

Hereditary elliptocytosis with protein band 4.1 deficiency in the dog.

A dog with persistent elliptocytosis was studied. The dog had membrane protein band 4.1 deficiency, microcytosis, shortened erythrocyte lifespan, increased osmotic sensitivity, and a mild glutathione deficiency. Erythrocyte deformability and membrane stability were adversely effected. The dog's parents had decreased band 4.1, decreased stability, and some elliptocytosis. This disorder in dogs closely resembles human patients with band 4.1 deficiency and should provide a valuable animal model to study the erythrocyte membrane cytoskeleton.

Animals↗