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Biomedical subjects

C J King

Publications and source records attributed to C J King.

At least 19 recordsLinked to original sources
PubMed2000

Human histologic evaluation of bioactive ceramic in the treatment of periodontal osseous defects.

This study examined the healing of intrabony defects around 5 teeth treated with bioactive glass ceramic (PerioGlas). Healing was evaluated by clinical measurements, radiographic observation, and histologic analysis. The protocol included a presurgical phase of scaling and root planing therapy, with measurements obtained immediately prior to the surgical procedures and after 6 months of healing. Following therapy there was a mean of 2.7 mm of probing depth reduction, 2.2 mm of clinical attachment gain, and 0.5 mm of recession. The histologic analysis revealed healing by a long junctional epithelium with minimal new connective tissue attachment to the teeth, except in one case where the intrabony region demonstrated new cementum formation and new connective tissue attachment. Graft particles were found to be biocompatible, as evidenced by being embedded in a stroma of dense connective tissue with minimal inflammatory infiltrate. There was minimal new bone formation limited to the most apical borders of the defects. No signs of periodontal regeneration as defined by new cementum, periodontal ligament, and bone formation on a previously diseased root surface were observed. Although the clinical results are encouraging and radiographs evidenced radiopacities within the defects, histologic analysis revealed that as a periodontal grafting material, bioactive glass ceramic has only limited regenerative properties.

Alveolar Bone Loss↗
PubMed1999

Ileal mucosal oxygen consumption is decreased in endotoxemic rats but is restored toward normal by treatment with aminoguanidine.

OBJECTIVE: We sought to test the hypothesis that ileal mucosal oxygen consumption is impaired in endotoxemic rats. METHODS: Male Sprague-Dawley rats were injected intravenously with either Escherichia coli lipopolysaccharide (5 mg/kg) or a similar volume of vehicle. A segment of ileum was excised 8 hrs later, and the serosal and muscular layers of the bowel were stripped away from the mucosa. A strip of mucosa was mounted in a polarographic chamber containing air-saturated Krebs-Henseleit buffer plus 20 mM glucose, PO2 being monitored during a 10-min period. Some rats were injected intraperitoneally with the inducible nitric oxide synthase inhibitor, aminoguanidine (30 mg/kg per dose), or a similar volume of vehicle, at 1, 3 and 6 hrs after injection of lipopolysaccharide. RESULTS: In an initial experiment, the rate of oxygen consumption was significantly lower for mucosal samples from endotoxemic rats as compared with control rats (0.76+/-0.11 ng-atoms vs. 1.42+/-0.22 ng-atoms of 0/min per microg dry weight, respectively; n = 8 per group; p<.05). The rate of mucosal oxygen consumption was higher in aminoguanidine-treated as compared with vehicle-treated endotoxemic rats (1.25+/-0.11 ng-atoms and 0.73+/-0.07 ng-atoms of 0/min per microg, respectively; n = 7 and n = 6, respectively; p<.05). CONCLUSION: Endotoxemia is associated with diminished intestinal mucosal oxygen utilization due to an intrinsic acquired derangement in cellular respiration that is caused, at least in part, by an aminoguanidine-inhibitable mechanism.

Animals↗
PubMed1998

Airway auscultation. A new method of confirming tracheal intubation.

Unrecognised accidental oesophageal intubation remains an important cause of morbidity and mortality in anaesthetic practice. We have evaluated a new method of distinguishing tracheal from oesophageal intubation using a simple adaptation of an ordinary stethoscope which is inserted into the patient end of the breathing system. We call this technique 'airway auscultation'. Characteristic sounds are heard with the stethoscope during inflation and deflation which allow the observer to diagnose the position of the tube. When the tube is in the trachea loud breath sounds are heard. In contrast, when the tube is in the oesophagus either squeaks or a flatus-like noise is heard or else there is no sound. In 100 healthy adults two observers rapidly identified 99 intubations correctly in a randomised single-blind trial. We recommend further widespread evaluation of this device as it appears to be an effective, simple and rapid method of detecting oesophageal intubation and confirming tracheal intubation which may be of particular use in situations where capnography is not available.

Adolescent↗
PubMed1997

An evaluation of bioactive ceramic in the treatment of periodontal osseous defects.

Bioglass particulates were surgically placed in the periodontal osseous defects of 12 patients. The clinical parameters studied were probing depth, attachment level as measured with the Florida Probe, and standardized bitewing radiograph comparisons. Data was collected initially, and at 3-, 6-, and 24-month posttreatment intervals. Statistically significant improvements were demonstrated in all clinical parameters studied. There was a mean probing depth reduction of 3.33 mm, a mean attachment gain of 1.92 mm, and a mean radiographic bone fill of 3.47 mm. Results were stable over the 24-month period. Ease of handling and excellent tissue response were characteristic of the material.

Adult↗
PubMed1995

Emergency use of the laryngeal mask airway in severe upper airway obstruction caused by supraglottic oedema.

We report two cases of severe upper airway obstruction caused by supraglottic oedema which developed rapidly at the time of anaesthesia. Conventional methods to relieve the obstruction failed and it was only overcome when a laryngeal mask airway (LMA) was inserted and positive pressure applied manually during inspiration. In one case a fibrescope was passed via the LMA and this revealed two cushions of oedematous false vocal cords protruding into the bowel of the LMA which were pushed out of the way when positive pressure was applied during inspiration. We believe that the LMA should be considered in the emergency management of severe upper airway obstruction even when this involves supraglottic oedema.

Airway Obstruction↗
PubMed1993

Urodynamic evaluation of the intrinsically incompetent sphincter.

Differentiating causes for stress incontinence is important because treatments differ. Treatment failure occurs when surgery used to correct pelvic descent is applied to the intrinsically incompetent sphincter. Urodynamic tests that discriminate these causes are discussed.

Diagnosis, Differential↗
PubMed1986

Phosphoribosylpyrophosphate synthetase of Escherichia coli. Properties of the purified enzyme and primary structure of the prs gene.

Phosphoribosylpyrophosphate (P-Rib-PP) synthetase of Escherichia coli has been purified to near homogeneity from a strain harboring the prs gene, encoding P-Rib-PP synthetase, on a multicopy plasmid. Analysis of the enzyme showed that it required inorganic phosphate for activity and for stability. Magnesium ions were required both as a complex with the substrate ATP and as a free cation. P-Rib-PP synthetase activity was inhibited strongly by ADP. Kinetic analysis indicated multiple sites of action of ADP. In addition apparent substrate inhibition was exerted by ribose 5-phosphate in the presence of ADP. The nucleotide sequence of the E. coli prs gene has been determined and the coding segment established. The deduced amino acid sequence of P-Rib-PP synthetase contained 314 amino acid residues and the molecular weight was calculated as 34,060. The initiation site of transcription was determined. This site was preceded by well conserved -10 and -35 consensus sequences (pdT-dA-dG-dA-dA-dT and pdT-dT-dG-dA-dT-dG, respectively). The transcription initiation site preceded the potential translation initiation site by 302 nucleotides. Transcription terminated approximately 35 nucleotides downstream from the UAA translation stop codon, within a Thy-rich region following an inverted repeat sequence, indicative of an rho-independent transcription terminator.

Amino Acid Sequence↗
PubMed1983

Cold-stage scanning electron microscope measurement of ice morphology in apple tissue as a function of freezing rate.

A cold-stage SEM was used to document the morphology of ice in apple tissue and a sucrose solution frozen at rates ranging from 450 to 0.03 degrees K/min. Freezing rates of 3-mm-thick apple discs were measured with a differential thermocouple technique, which gave measurement of the growth velocity and the temperature gradient through the solidified specimen as well as the cooling rate during solidification. Cold-stage SEM micrographs were used to measure the dendritic spacing of the ice structures, and these data were found to correlate linearly with the square root of the cooling rate during solidification as would be predicted by a theoretical analysis of mass transfer in the formation of dendrites. Comparison of freeze-substituted and freeze-dried apple-tissue micrographs with those from a cold-stage SEM showed that the cold-stage SEM technique was the only one which correctly represented ice morphology in apple tissue.

Food Preservation↗