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K B Carter

Publications and source records attributed to K B Carter.

At least 19 recordsLinked to original sources
PubMed2000

Species-specific PCR as a tool for the identification of Burkholderia gladioli.

Burkholderia gladioli colonizes the respiratory tracts of patients with cystic fibrosis and chronic granulomatous disease. However, due to the high degree of phenotypic similarity between this species and closely related species in the Burkholderia cepacia complex, accurate identification is difficult. Incorrect identification of these species may have serious repercussions for the management of patients with cystic fibrosis. To develop an accurate procedure for the identification of B. gladioli, a molecular method to discriminate between this species and other species commonly isolated from the sputa of patients with cystic fibrosis was investigated. The 23S ribosomal DNA was cloned from several clinical isolates of B. gladioli, and the nucleotide sequence was determined. Computer-assisted sequence comparisons indicated four regions of the 23S rRNA specific for this species; these regions were used to design three primer pairs for species-specific PCR. Two of the primer pairs showed 100% sensitivity and specificity for B. gladioli when tested against a panel of 47 isolates comprising 19 B. gladioli isolates and 28 isolates of 16 other bacterial species. One of the primer pairs was further assessed for species specificity by using a panel of 102 isolates obtained from the Burkholderia cepacia Research Laboratory and Repository. The species-specific PCR was positive for 70 of 74 isolates of B. gladioli and was negative for all other bacterial species examined. Overall, this primer pair displayed a sensitivity and specificity of 96% (89 of 93) and 100%, respectively. These data demonstrate the potential of species-specific PCR for the identification of B. gladioli.

Burkholderia↗
PubMed2000

Identification and detection of Stenotrophomonas maltophilia by rRNA-directed PCR.

Stenotrophomonas maltophilia has recently emerged as an important nosocomial pathogen in immunocompromised patients, in transplant recipients, and in persons with cystic fibrosis (CF). While this organism is nonpathogenic in healthy individuals, it is increasingly associated with morbidity and mortality in susceptible populations. Recent studies have indicated that for approximately 10% of CF patients with moderate lung disease, S. maltophilia can be cultured from respiratory tract secretions. Identification of S. maltophilia can be problematic, and analysis of isolates from the Burkholderia cepacia Research Laboratory and Repository showed that several isolates presumptively identified as B. cepacia by clinical microbiology laboratories were in fact S. maltophilia. To overcome the problems associated with definitive identification, we developed species-specific PCR (SS-PCR) primers, designated SM1 and SM4, directed to the 23S rRNA gene, and tested their utility to accurately identify S. maltophilia directly from sputum. The SS-PCR was developed and tested against a panel of 112 S. maltophilia isolates collected from diverse geographic locations. To test for specificity, 43 isolates from 17 different species were analyzed. PCR with the SM1-SM4 primer pair and isolated genomic DNA as a template resulted in amplification of a band from all S. maltophilia isolates and was uniformly negative for all other species tested, yielding a sensitivity and a specificity of 100% for the SS-PCR. The utility of the SS-PCR to directly identify S. maltophilia in sputum was examined. Thirteen expectorated sputum samples from CF patients were analyzed by SS-PCR. Three samples were PCR positive, in complete concordance with the conventional laboratory culture. Thus, we have developed an SS-PCR protocol that can rapidly and accurately identify S. maltophilia isolates and which can be used for the direct detection of this organism in CF patient sputum.

Cloning, Molecular↗
PubMed2000

Identification of members of the Burkholderia cepacia complex by species-specific PCR.

Definitive identification of the species in the Burkholderia cepacia complex by routine clinical microbiology methods is difficult. Phenotypic tests to identify B. multivorans and B. vietnamiensis have been established; more recent work indicates B. stabilis may also be identified by growth characteristics and biochemical tests. However, attempts to identify genomovars I and III have, thus far, proved unsuccessful. Previously, we demonstrated the utility of two primer pairs, directed to the rRNA operon, to specifically identify the B. cepacia complex in a PCR. One of these primer pairs, G1-G2, only amplified a DNA fragment from genomovars I and III and B. stabilis in a PCR with genomic DNA isolated from prototypical strains representing the five genomovars. Sequence analysis of the rRNA operon for all the genomovars indicated that this primer pair targeted a region shared by these isolates. Further analysis revealed a region of heterogeneity between genomovar III and B. stabilis internal to the amplified product of G1-G2. Primers designed to target this region were tested with prototypical strains following an initial amplification with the G1-G2 primer pair. New primers specific for the prototypical genomovar III and B. stabilis were designated SPR3 and SPR4, respectively. Analysis of 93 isolates representing 18 genomovar I, 13 B. multivorans, 36 genomovar III, 11 B. stabilis, and 15 B. vietnamiensis isolates was performed. DNA from all isolates of genomovars I and III and B. stabilis was amplified by G1-G2. Genomovar III isolates yielded a product with SPR3/G1 while B. stabilis amplified with SPR4-G1. Genomovar I isolates were amplified by either SPR3-G1 or SPR4-G1, but not both. B. multivorans yielded a product with SPR3-G1 but not G1-G2, and B. vietnamiensis isolates were negative in all PCRs. Thus using an algorithm with G1-G2, SPR3-G1, and SPR4-G1 primers in a PCR analysis, genomovar III isolates can be separated from B. stabilis and the identity of B. multivorans and B. vietnamiensis can be confirmed.

Burkholderia Infections↗
PubMed1999

On the spontaneous mutability of CpG sites in cultured S49 mouse lymphoma cells.

The frequent occurrence of human mutations at CpG dinucleotide sites has been attributed to cytosine methylation and hydrolytic deamination of the resulting 5-methylcytosine residue. Previously, we reported an unusually strong hotspot for spontaneous transitions at a CpG site in the gene for regulatory (R) subunit of protein kinase A in S49 mouse lymphoma cells. Now, using polymerase chain reaction-based methods to screen mutant populations for mutations at particular CpG sites, we show that two methylated CpG sites in the gene for hypoxanthine phosphoribosyltransferase are much less mutable than the R subunit hotspot site, suggesting that different methylated CpG sites are differentially susceptible to spontaneous mutation. We also present data on spontaneous R subunit mutations in cloned populations of 5-azacytidine-treated S49 cells that had been demethylated at the hotspot site in both R subunit alleles. Of 13 independent mutants isolated from populations grown from fully demethylated cells, seven had the hotspot mutation. We conclude that CG-->TA mutations at strong CpG hotspots do not require prior methylation of CpG sites.

5-Methylcytosine↗
PubMed1998

Physiological phosphorylation of protein kinase A at Thr-197 is by a protein kinase A kinase.

Phosphorylation of the catalytic subunit of cyclic AMP-dependent protein kinase, or protein kinase A, on Thr-197 is required for optimal enzyme activity, and enzyme isolated from either animal sources or bacterial expression strains is found phosphorylated at this site. Autophosphorylation of Thr-197 occurs in Escherichia coli and in vitro but is an inefficient intermolecular reaction catalyzed primarily by active, previously phosphorylated molecules. In contrast, the Thr-197 phosphorylation of newly synthesized protein kinase A in intact S49 mouse lymphoma cells is both efficient and insensitive to activators or inhibitors of intracellular protein kinase A. Using [35S]methionine-labeled, nonphosphorylated, recombinant catalytic subunit as the substrate in a gel mobility shift assay, we have identified an activity in extracts of protein kinase A-deficient S49 cells that phosphorylates catalytic subunit on Thr-197. The protein kinase A kinase activity partially purified by anion-exchange and hydroxylapatite chromatography is an efficient catalyst of protein kinase A phosphorylation in terms of both a low Km for ATP and a rapid time course. Phosphorylation of wild-type catalytic subunit by the kinase kinase activates the subunit for binding to a pseudosubstrate peptide inhibitor of protein kinase A. By both the gel shift assay and a [gamma-32P]ATP incorporation assay, the enzyme is active on wild-type catalytic subunit and on an inactive mutant with Met substituted for Lys-72 but inactive on a mutant with Ala substituted for Thr-197. Combined with the results from mutant subunits, phosphoamino acid analysis suggests that the enzyme is specific for phosphorylation of Thr-197.

Amino Acid Sequence↗
PubMed1997

Assessment of a novel implantable artificial anal sphincter.

PURPOSE: The aim of the study was to test a new implantable artificial anal sphincter in the porcine model. METHOD: The artificial sphincter, which includes an inflatable expander that compresses and flattens the bowel against a pillow, was implanted in 16 animals and studied for periods of up to 20 weeks. The anal sphincters were destroyed, and the efficacy of the device in rendering the animals continent was studied. RESULTS: Of the 11 animals in which the artificial sphincter was regularly closed, 8 completed the study and were continent during 85 percent of activation times. There was no evidence of ischemic injury. Major complications were related only to failure of the control pumps of the device. CONCLUSION: This study suggests that this neosphincter produces fecal continence without intestinal ischemia. At present reliability is limited only by the performance of the pump.

Anal Canal↗
PubMed1996

Anorectal angle enhances faecal continence.

This study was performed with an in vitro model to assess the relative importance of sphincter pressure and anorectal angulation in maintaining faecal continence. Water and semisolid material were infused separately into porcine intestine compressed by an inflatable cuff until leakage was observed. Angulation of the bowel with respect to the cuff was 180 degrees and then 90 degrees. With water, holdback pressure was independent of angulation. In contrast, when semisolid material was used, angling the bowel to 90 degrees increased holdback pressure by at least 100 per cent. Measurements taken in solid tubes demonstrated that both a restriction in the tube and an unconstricted 90 degrees bend produced a resistance to flow of the semisolid material which was dependent on flow rate. These data suggest that liquid is retained in the rectum by occlusion pressure alone, whereas the retention of semisolid material is enhanced by angulation.

Anal Canal↗
PubMed1992

Does ispaghula husk stimulate the entire colon in diverticular disease?

The effect of ispaghula husk on colonic motility of the right and left side was examined in 10 patients with left sided diverticular disease using an untethered pressure sensitive radiotelemetry capsule. After treatment, ispaghula husk reduced mouth to rectum transit by a median of 8.8 hours and the time to midtransverse colon by five hours. In the right colon there was an increase in the median percentage activity of 7% and the median number of pressure waves greater than 5 mm Hg/hour rose by 35.3. Motility changes in the left colon were less pronounced. Five of the seven patients with abdominal pain and six of the nine patients with altered bowel habit responded to treatment. These results suggest that it is ispaghula husk's action on the right unaffected colon which alleviates the symptoms of left sided diverticular disease.

Aged↗
PubMed1991

Energy expenditure and protein synthesis rates in an animal model of cancer cachexia.

Food intake and energy expenditure of cachectic tumour bearing mice were measured during the course of weight loss. Four weeks after implantation of the MAC-16 tumour the body weight was reduced by 20%, there was no significant reduction in food intake, and body composition analysis revealed that both body fat and protein mass were decreased. Oxygen consumption and carbon dioxide production were measured over a 24h period both before and at weekly intervals after tumour implantation. There was a gradual increase in the rates of both oxygen consumption and carbon dioxide production per gram body weight. Similarly, energy expenditure per gram body weight was increased during the 3rd (11%) and 4th (23%) weeks. In contrast, the food intake per gram body weight was unchanged during the first three weeks and increased by only 8% during the 4th week. Despite the development of cachexia, rates of protein synthesis in the liver, heart, kidney and skeletal muscle were the same four weeks after tumour implantation as those in non-tumour bearing mice. Thus, in this murine model of cancer cachexia a negative energy balance resulted from failure of food intake to compensate for increased energy demands. These findings point to the unique pattern of metabolic alterations which occur in different models of cancer cachexia.

Journal Article↗
PubMed1988

Long-term performance of Tec vaporizers. Basis for a rational maintenance policy.

We reviewed the maintenance records of Tec vaporizers which had been in clinical use for up to 4 years. Tec 4s and Enfluratec 3s were found to be extremely reliable, but Fluotec 3s suffered progressively from mechanical and calibration problems. Their most recurrent fault was sticking valves caused probably by thymol crystallizing on the valve faces. This fault did not occur with Fluotec 4s, which are designed to prevent liquid agent reaching the valve surfaces. We found, in a study of the effects of thymol accumulation, that only occasional draining of a Fluotec vaporizer is required to keep thymol concentration below the level at which its output is reduced. We conclude that, if regular field calibration checks are carried out as a safety measure, the service interval for Tec vaporizers could be extended beyond Ohmeda's present recommendation of one year.

Anesthesia, Inhalation↗
PubMed1986

Exposure of midwives to nitrous oxide in four hospitals.

The exposure of midwives to nitrous oxide in four hospitals was measured with personal samplers. In three of the four hospitals the average exposure was not significantly less than 100 parts per million (ppm). In one hospital the average exposure was 360 ppm; this was reduced by a factor of about 2.5 when a trial scavenging system was used. Differences in working practices and in the layout, size, and ventilation of the labour suites contributed to the observed differences in average exposure. Midwives and other staff working in the labour room are potentially at risk from excessive occupational exposure to nitrous oxide.

Anesthesia, Obstetrical↗
PubMed1986

Evaluation of keyed fillers on TEC vaporizers.

Single and dual port versions of the keyed fillers fitted to TEC4 and TEC3 vaporizers, respectively, were examined. The single port filler performed satisfactorily, provided that it was correctly used and properly maintained. Design deficiencies in the dual-port keyed filler were found which accounted for many of the problems described by users. The keyed bottle adaptor could be improved by an increase in its length and the provision of two openings into the outer tube at the bottle end.

Anesthesia, Inhalation↗
PubMed1986

A disposable device for infusion analgesia. An evaluation of the Travenol infusor.

The performance of the Travenol infusor when used to administer an intravenous infusion of analgesic after surgery has been investigated. Mean flow was very similar to the manufacturer's quoted figure of 2 ml/hour, but there was a large interindividual variation. Results from a laboratory study suggest that this was due to variation in the manufacture of the infusor.

Disposable Equipment↗
PubMed1984

Medishield AGS system and servo 900 ventilators. Investigation and remedy of hazard caused by defeat of 'low expired minute volume' alarm.

The use of the new Medishield anaesthetic gas scavenging system with ventilators in the Siemens-Elema Servo 900 series was investigated. It was discovered that this combination of equipment creates the hazard that a disconnexion in the patient breathing system may not be detected by the ventilator alarm. This happens because the suction generated by the scavenging system draws a considerable flow of room air through the expiratory system of the ventilator when a disconnexion occurs. Possible solutions to the problem were investigated, and it was discovered that the problem can be overcome by applying a small amount of positive end-expiratory pressure to counteract the suction from the scavenging system.

Air Pollution↗
PubMed1979

Survey of operating room pollution within an N.H.S. district.

Pollution by waste anaesthetic gases was measured in all operating departments in a typical N.H.S. district. Methods were chosen to provide time-weighted average levels over the period of each operating session. The results showed that air-conditioning alone could not guarantee pollution levels below suggested maximum levels and that to meet those requirements air-conditioning plus scavenging was necessary. Background pollution levels were found to be representative of the personal exposure of nursing staff but approximated to only one third of the anaesthetists' personal exposure. Dental clinics presented special problems, namely the very high levels of pollution to which the dentist and his assistants were exposed.

Air Conditioning↗
PubMed1978

A chemical adsorption system for the sampling of gaseous organic pollutants in operating theatre atmospheres.

The development of an air sampler and its use in measuring organic pollutants in operating theatre atmospheres are described. Air was sampled continuously during an operating session and the results obtained represent the average pollution at the sample site during that session. The technique involved the chemical adsorption of organic vapours to polymer beads and pollutants thus trapped could be stored for several days before thermal desorption and analysis by gas chromatography. The three most abundant organic pollutants were ethanol, propan-2-ol (isopropanol) and halothane.

Adsorption↗