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Biomedical subjects

W J Harris

Publications and source records attributed to W J Harris.

At least 19 recordsLinked to original sources
PubMed1992

Methods for assessing condition-specific and generic functional status outcomes after total knee replacement.

Many assume that, relative to generic measures, condition-specific health measures are both more sensitive to the condition's severity and more specific because they are less affected by other conditions. We analyzed the sensitivity and specificity of the generic SF-36, condition-specific scales based on the SF-36, and condition-specific measures based on the Knee Society's Clinical Rating System in a study of osteoarthritis patients following knee replacement. As hypothesized, knee-specific role function and pain measures were more specific than generic measures among patients with other comorbid conditions, and less so among patients with only knee problems. Physical function scales of both types were equally specific. Clinical indicators based on x-ray and range of motion were only weakly related to all measures of function.

Activities of Daily Living↗
PubMed1992

Uterine dehiscence following laparoscopic myomectomy.

BACKGROUND: Laparoscopic myomectomy is a new procedure that is growing in popularity. The natural history of pregnancy following laparoscopic myomectomy is unknown. CASE: A 24-year-old white woman, gravida 0, with infertility and endometriosis, conceived after a laparoscopic procedure that included myomectomy. At 34 weeks' gestation, the patient experienced uterine dehiscence at the site of myomectomy. An emergency cesarean delivery was performed and the uterus was oversewn. Both mother and infant had satisfactory hospital courses. CONCLUSION: Meticulous closure of the myometrial bed following myomectomy is difficult via the laparoscope, and this could interfere with the integrity of the scar. If further studies confirm this experience, then laparoscopic myomectomy may need to be limited to patients who do not desire further childbearing.

Adult↗
PubMed1991

Sequence of a cellulase gene from the rumen anaerobe Ruminococcus flavefaciens 17.

A cellulase gene (endA) was isolated from a library of Ruminococcus flavefaciens strain 17 DNA fragments inserted in pUC13. The endA product showed activity against acid-swollen cellulose, carboxymethyl-cellulose, lichenan, cellopentaose and cellotetraose, but showed no activity against cellotriose or binding to avicel. Nucleotide sequencing indicated an encoded product of 455 amino acids which showed significant sequence similarity (ranging from 56% to 61%) with three endoglucanases from Ruminococcus albus, and with Clostridium thermocellum endoglucanase E. Little relatedness was found with a cellodextrinase previously isolated from R. flavefaciens FD1.

Amino Acid Sequence↗
PubMed1991

Reshaping a human monoclonal antibody to inhibit human respiratory syncytial virus infection in vivo.

We transferred the complementarity determining regions from a murine monoclonal antibody that neutralizes infection by respiratory syncytial virus (RSV) to a human IgG1 monoclonal antibody. The resulting reshaped human antibody lost affinity for RSV, but an additional alteration to one of the framework regions restored binding affinity and specificity. This second generation reshaped human monoclonal antibody cross-reacted with all clinical isolates of RSV tested and both prevented disease and cured mice even when administered four days after infection. We expect the antibody will prove useful in the management of this major childhood disease.

Amino Acid Sequence↗
PubMed1978

DNA polymerases from Chlamydomonas reinhardii. Purification and properties.

Three DNA polymerase activities, A, B and C, were identified in extracts of exponentially growing synchronous cultures of Chlamydomonas reinhardii, and DNA polymerases A and B were characterized in detail. Both enzymes have the same binding affinity for DEAE-cellulose at pH 7.8, but can be distinguished from each other by their behaviour on phosphocellulose and DNA-agarose. 'Activated' calf thymus DNA was used as template, and the pH, K+ and bivalent-cation optima were measured. DNA polymerase A sediments at 5.3 S in glycerol gradients, with an apparent mol.wt. of 90000-100000. Polymerase B sediments between 8S and 10S in 100mM-KCl, the predominant species having an apparent mol.wt. of 200000. In 200mM-KCl, polymerase B dissociates to a single species, which sediments at 5.8S. A 3S species was found in aged preparations of both enzymes. The activity of polymerase B from cells harvested during nuclear DNA synthesis is twice that found in Chlamydomonas at other times during the cell cycle.

Cations↗
PubMed1978

DNA polymerases from Chlamydomonas reinhardii. Further characterization, action of inhibitors and associated nuclease activities.

The properties of three DNA polymerase species A, B and C, purified from Chlamydomonas reinhardii were compared. DNA polymerases A and B have Km values with respect to deoxyribonucleoside triphosphates of 19 micron and 3 micron respectively. DNA polymerase A is most active with activated DNA, but will also use native DNA and synthetic RNA and DNA templates with DNA primers. DNA polymerase B is also most active with activated DNA, but will use denatured DNA and synthetic DNA templates. It is inactive with RNA templates. DNA polymerase B is completely inactive in the presence of 100 micron-heparin, which has no effect on DNA polymerase A activity. Heparin dissociates DNA polymerase B into subunits that are still catalytically active, but which heparin inhibited. DNA polymerase B possesses deoxyribonuclease activity that is inhibited by 5 micron-heparin, suggesting that the deoxyribonuclease is an integral part of the DNA polymerase moiety. DNA polymerase A is devoid of nuclease activity. DNA polymerase C is similar to DNA polymerase B in all these properties, though it is more active with RNA primers and has greater heat-sensitivity.

Chlamydomonas↗
PubMed1977

A deoxyribonuclease from Chlamydomonas reinhardii. 1. Purification and properties.

A deoxyribonuclease has been purified more than 2000-fold from the green algae, Chlamydomonas reinhardii. The enzyme is most active on denatured DNA. Optimum activity is at pH 8.5, in 80 mM Tris-HCl buffer and 2 mM CaCl2. Other divalent cations can replace Ca2+ with varying lower efficiency. EDTA and inorganic phosphate are strongly inhibitory, while ATP and high concentrations of 2-mercaptoethanol are slightly inhibitory. The molecular weight is approximately 35 000, the Stokes radius is 2.7 nm, and the sedimentation coefficient 2.8 S. It is a single polypeptide chain, and the frictional ratio of 1.27 suggests it is only slightly asymetrical. The isoelectric point is 9.5. This enzyme has been termed exonuclease 1.

Adenosine Triphosphate↗
PubMed1977

A deoxyribonuclease from Chlamydomonas reinhardii. 2. Substrate specificity, mode of action and products.

A deoxyribonuclease purified Chlamydomonas reinhardii has been shown to be specific for single-stranded DNA. The enzyme is most active on thermally denatured DNA, but also degrades single-stranded termini from double-stranded DNA. The enzyme has no effect on single-stranded or double-stranded intact circular phiX174DNA, suggesting that it requires DNA termini for activity. DNA is digested progressively to oligonucleotides and then mononucleotides. The product of the reaction is nucleoside 5'-monophosphates. The enzyme has no effect on RNA, nor does it possess phosphatase or phosphodiesterase activity. No specificity was demonstrated for phosphate or hydroxyl groups at either the 5' or 3' termini of DNA. The enzyme may be able to initiate hydrolysis at either the 3' or the 5' termini, since radioactivity was released more rapidly from 5' and 3' termini than from bulk DNA. The enzyme has been tentatively named Chlamydomonas reinhardii exonuclease 1.

Chlamydomonas↗
PubMed1977

An investigation of relationships between teachers' ratings of behavior and children's personality traits.

This study examined the relationships between teachers' ratings of children's behavior on the Behavior Problem Checklist and children's self-reported personality source traits on age-appropriate Personality Questionnaires. The sample consisted of 254 children from first through eighth grades and 13 teachers in a rural Maine elementary school. Analysis of the data revealed that teachers' ratings and children's self-reports in grades four through six agreed more frequently about problematic behavior than did children's self-reports and teachers self-ratings in grades one through three and seven and eight. In general, the study (1) supported the validity of teacher judgments made with the Behavior Problem Checklist, (2) demonstrated the critical need for more than one perspective when identifying and defining maladaptive behavior potentially indicative of emotional disturbance, and (3) suggested the need to increase the accuracy of teachers' perceptions and evaluations of children's behavior.

Adolescent↗
PubMed1975

Thymineless death in Bacillus subtilis.

A study has been made of the intracellular changes occurring during thymineless death in Bacillus subtilis 2337. The kinetics of death were paralleled by the rate of breakdown of DNA. During thymineless death single-strand breaks accumulated within DNA, breakdown of approximately 13% of the DNA to acid-soluble material occurred, deoxyribonuclease levels rose sharply, and yet double-strand breaks did not occur in the DNA. On restoration of thymine, however, double-strand breaks accumulated, though this could be prevented by the specific inhibition of DNA preplication on restoration of thymine. The results probably indicate that during thymineless death, single-strand gaps accumulate within the DNA of cells. On restoration of thymine both DNA replicaion and repair of gaps are simultaneously initiated, and when a replication fork reaches a gap before it is repaired, double-strand breakage of the DNA occurs. The possible relevance of these events to the lethality of the cells is discussed.

Bacillus subtilis↗