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Biomedical subjects

M C Roberts

Publications and source records attributed to M C Roberts.

At least 181 records · Page 10Linked to original sources
PubMed1987

Chromosomal DNA probes for the identification of Bacteroides species.

We compared 22 Bacteroides species by DNA-DNA homology studies using the S1 endonuclease method. None of the currently defined species shared more than 30% DNA homology with any other species examined with the exception of B. buccae and B. capillus (which along with B. pentosaceus are now considered a single species), which shared 86% of their DNA sequences. Two clusters showed weak genetic relationships, with DNA homology greater than 10%. The first cluster included B. coporis, B. disiens, B. bivius, B. intermedius and B. melaninogenicus. The second cluster included B. fragilis, B. eggerthii, B. ovatus, B. thetaiotaomicron and B. uniformis. Five of the oral species, B. asaccharolyticus, B. gingivalis, B. loescheii, B. intermedius and B. melanogenicus, were chosen for study as whole chromosomal probes in dot blot assays. These were tested against 243 clinical strains biochemically identified as Bacteroides species. The DNA probes correctly identified 94% of the clinical strains. DNA probe and biochemical identification was 100% for two of the five species. In contrast, only 86% of the strains biochemically identified as B. intermedius were identified by the DNA probe. The DNA probes gave a species identification to seven strains which could not be biochemically identified.

Bacteroides↗
PubMed1987

Cloning and characterization of tetM gene from a Ureaplasma urealyticum strain.

We have cloned a 4.9-kilobase (kb) HincII fragment which contains a tetracycline resistance determinant (tetM) from the chromosome of Ureaplasma urealyticum. The 4.9-kb HincII fragment contains DNA in addition to the structural gene, is closely related to the previously characterized 5.0-kb fragment from pJI3, and contains no normal ureaplasmal DNA sequences.

Cloning, Molecular↗
PubMed1987

Whole chromosomal DNA probes for rapid identification of Mycobacterium tuberculosis and Mycobacterium avium complex.

Whole chromosomal DNA probes were used to identify clinical isolates of Mycobacterium tuberculosis, Mycobacterium avium complex, and Mycobacterium gordonae. The probe for M. tuberculosis was prepared from Mycobacterium bovis BCG, which has been shown to be closely related to M. tuberculosis. A probe for the M. avium complex was prepared from three strains representing each of the three DNA homology groups in the M. avium complex. The probes were used in dot blot assays to identify clinical isolates of mycobacteria. The dot blot test correctly identified 57 of the 61 (93%) cultures grown on solid media, and 100% of antibiotic-treated broth-grown cells were correctly identified. Identification by dot blot required a maximum of 48 h. When the probes were tested against 63 positive BACTEC (Johnston Laboratories, Inc., Towson, Md.) cultures of clinical specimens, 59% were correctly identified. However, of the 14 BACTEC cultures that had been treated with antibiotics before being lysed, 13 (93%) were correctly identified.

Chromosomes, Bacterial↗
PubMed1987

Interstitial emphysema associated with epidural anesthesia for extracorporeal shock-wave lithotripsy.

Interstitial emphysema was noted on abdominal radiographs in 38 (15%) of the first 150 patients treated by extracorporeal shock-wave lithotripsy at our hospital. All 38 patients had undergone successful or attempted epidural anesthesia for the lithotripsy. This finding was not seen in any patient who had not undergone epidural puncture. The emphysema is the result of the introduction of air into the paraspinal and back muscles or subcutaneous tissues during attempted or actual puncture of the epidural space. This air was apparent on abdominal radiographs taken after lumbar puncture in 38 (23%) of 167 patients who underwent attempted or actual puncture of the epidural space. The emphysema decreases over the ensuing days, is of no clinical significance, and bears no direct relationship to extracorporeal shock-wave lithotripsy. This finding should not be mistaken for emphysema caused by gas-producing or gas-containing retroperitoneal diseases.

Anesthesia, Epidural↗
PubMed1987

DNA probes for the detection of mycoplasmas in genital specimens.

The utility of whole-genomic DNA probes for the detection of infections by genital mycoplasmas was investigated in 220 men attending a sexually transmitted diseases clinic. In 144 patients, probe results were compared with quantitative culture results. The prevalence of Mycoplasma hominis was 11% by culture, whereas the prevalence of ureaplasmas was 38%. The M. hominis DNA probe detected 9 of 16 M. hominis culture-positive specimens and 2 of 128 culture-negative specimens. The Ureaplasma urealyticum DNA probe detected 36 of 57 U. urealyticum culture-positive specimens and 18 of 87 culture-negative specimens. Most of the probe-negative culture-positive specimens had colony counts of less than 10(3) organisms/ml of specimen. The DNA probe does not require viable organisms, and the probe-positive, culture-negative specimens suggest that false-negative cultures occurred, perhaps due to specimen handling or insensitivity of culture methods for some strains of mycoplasmas.

Bacteriological Techniques↗
PubMed1986

Health psychology for children: a step-child/stepping stone.

This paper presents the position that health psychology for children is not given proper attention in mainstream health psychology, which is primarily adult in orientation. It is proposed that the neglect of child-related problems in the recent Proceedings of the National Conference on Training in Health Psychology exemplifies the general orientation of mainstream health psychology, which views children's health problems primarily in terms of their effect on adult health rather than as problems that need current and immediate attention. We propose that applying a developmental perspective to the health psychology field would be one way of highlighting the fact that children's problems are unique and that children need to be viewed as something other than potential consumers of adult health psychology services or as agents for the prevention of adult health problems.

Child↗
PubMed1986

Rewarding elementary schoolchildren for their use of safety belts.

This study reports on the application of reward procedures to elementary schoolchildren to increase their use of seat belts en route to two schools. Following strict rules for assessing buckle-up compliance, all passengers in a car had to be safely secured in order for the schoolchildren to receive rewards. Compliant children received paper slips as they arrived at schools, which were redeemable for stickers, bumper stickers, and coloring books. The slips were also used in weekly drawings for pizza dinners. The mean compliance rate for School 1 was 4.3% during baseline, 66.2% for the reward phase across 4 weeks, 60% for return to baseline, 17.2% for Follow-Up 1, and 8.5% for Follow-Up 2. For School 2, the mean percentage was 5.3% at baseline, 69.8% for the reward phase, 68.5% for return to baseline, 40.1% for Follow-Up 1, and 20% for Follow-Up 2. These results indicate that rewarding the schoolchildren increased their own seat-belt use as well as that of their adult drivers and other passengers. Decreases in usage were observed after the rewards were removed.

Child↗
PubMed1986

Characterization of Haemophilus parainfluenzae strains with low-Mr or ladder-like lipopolysaccharides.

Twenty-five Haemophilus parainfluenzae strains were characterized for lipopolysaccharide (LPS) profiles, outer membrane protein profiles, serum sensitivity, plasmid profiles and DNA homology. Seventeen strains produced low-Mr LPS that did not contain O-sidechains, while the remaining eight strains contained ladder-like LPS suggestive of O-repeated units. This is the first time in the genus Haemophilus that LPS with O-repeated groups has been described. The strains producing the different types of LPS could not be distinguished from each other in outer membrane protein profiles or the other characteristics examined.

Bacterial Outer Membrane Proteins↗
PubMed1986

Characterisation of Haemophilus spp. isolated from infant conjunctivitis.

Haemophilus strains isolated from children under the age of 11 months with conjunctivitis were characterised by biotype, sugar fermentation, plasmid pattern and outer-membrane-protein profiles. H. influenzae was the most common species identified and was separated into 14 groups based on sugar fermentation and biotype patterns and into more than 20 groups when plasmid and outer-membrane-protein profiles were included. Small (mol. wt less than 10 X 10(6)) plasmids were identified in 11 of 34 (32%) H. influenzae isolates, 1 of 2 H. haemolyticus and 4 of 6 (67%) H. parainfluenzae isolates. Examination of sugar-fermentation and plasmid patterns increased the ability to distinguish between strains isolated at different times from recurrent disease and may have general applications in the study of Haemophilus strains isolated from a single anatomical site.

Bacterial Outer Membrane Proteins↗
PubMed1986

Effects of amitraz, several opiate derivatives and anticholinergic agents on intestinal transit in ponies.

Amitraz, atropine, glycopyrrolate and morphine (but not its derivatives, meperidine [pethidine], oxymorphone and butorphanol) produced similar effects on clinically observed intestinal functions and significantly prolonged intestinal transit, as assessed with polyethylene glycol (PEG). However, their mechanisms of action, particularly on intestinal transport (fluid movement), may differ widely. Loperamide appeared to exert a preferential action on intestinal transport rather than motility, as there was no significant delay in PEG transit. The action of amitraz in perturbing smooth muscle coordination and enhancing absorption involved, at least partially, an alpha 2 adrenergic component susceptible to yohimbine. Naloxone, an opiate antagonist, did not influence amitraz responses but induced the return of intestinal sounds and defecation after a refractory period in morphine-dosed ponies. The results suggest potential clinical applications in horses for loperamide in diarrhoea therapy, for alpha 2 adrenergic antagonists in obstruction and ileus and, possibly, of amitraz-like agents in reducing fluid losses in diarrhoea.

Animals↗
PubMed1986

Plasmid-encoded amikacin resistance in multiresistant strains of Klebsiella pneumoniae isolated from neonates with meningitis.

Two multiresistant Klebsiella pneumoniae strains isolated from cerebrospinal fluid of human neonates were analyzed for their plasmid content. Two of the plasmids harbored by these strains, pJHCMW1 (11 kilobase pairs) and pJHCMW4 (75 kilobase pairs), carried genetic determinants for amikacin resistance. These plasmids also encoded resistance to kanamycin, tobramycin, and ampicillin which could be transferred to Escherichia coli by conjugation. Extracts from transconjugant derivatives carrying pJHCMW4 produced an acetyltransferase activity that acetylated all three aminoglycosides. Transconjugant derivatives carrying pJHCMW1 encoded both acetylating and phosphorylating activities. Southern blot hybridization analysis indicated considerable DNA homology between these two plasmids.

Acetyltransferases↗