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R J Harris

Publications and source records attributed to R J Harris.

At least 37 records · Page 2Linked to original sources
PubMed2001

Histologic evaluation of root coverage obtained with GTR in humans: a case report.

The purpose of this study was to histologically evaluate four teeth with recession defects that were treated with guided tissue regeneration (GTR). The amount of root coverage obtained ranged from 16.7% to 50.0%. In one of the defects treated, new bone was formed but none of the new bone was coronal to the original gingival margin. Additionally, in this one case new cementum and connective tissue attachment was formed. However, because the new bone, new cementum, and new connective tissue were not coronal to the original gingival margin, this result could not be classified as regeneration. The vast majority of the attachment in this defect was long junctional epithelial attachment in the portion of the recession defect covered by the root-coverage procedure. In the other three defects treated, there was a loss of bone. All of the root coverage obtained was a long junctional epithelial attachment in three of the four defects. The results of this study do not show regeneration in any of the four defects treated.

Alveolar Bone Loss↗
PubMed2001

Gingival augmentation with an acellular dermal matrix: human histologic evaluation of a case--placement of the graft on bone.

The importance of gingival augmentation to increase the amount of keratinized tissue is a controversial subject. In this case report, an acellular dermal matrix was used to obtain an increase in the amount of keratinized tissue around four implants. In this case, the acellular dermal matrix was placed on bone. The surgical procedure resulted in an increase in the amount of keratinized tissue. Therefore, it met the clinical goals of the surgical procedure. However, the clinical findings and patient pain levels during the healing seemed to resemble a denudation procedure. Additionally, the histologic evaluation of the tissue that formed around the implants showed that the acellular dermal matrix was not incorporated into the result. Based on this case, the use of an acellular dermal matrix placed on bone does not seem to be a good technique to increase the amount of keratinized tissue.

Aged↗
PubMed2000

Granulocyte-macrophage colony-stimulating factor as an autocrine survival factor for mature normal and malignant B lymphocytes.

The role of GM-CSF in B cell (patho)physiology is unclear. Although B cells can respond to GM-CSF, there is controversy concerning the extent to which various resting and activated B cell types can themselves produce this cytokine, and the possibility that it can function in an autocrine fashion has not previously been considered. The aim of the present study was to address these issues using hairy cells (HCs) and chronic lymphocytic leukemia cells, two intrinsically activated mature malignant B cell types (with activation being more uniform and more pronounced in HCs). Normal B cells were used for comparison. Using a number of techniques, we demonstrated the constitutive production of GM-CSF by all three cell types and showed that the cytokine was biologically active. GM-CSF mRNA and protein were increased after cell activation by PMA, and constitutive production of the cytokine was highest in HCs, suggesting that the level of GM-CSF production is influenced by cell activation. Because GM-CSF is known to be antiapoptotic for myeloid cells, we used blocking anti-GM-CSF Abs to examine the contribution of autocrinely produced cytokine to cell survival. The Abs produced marked reduction in the in vitro survival of HCs, chronic lymphocytic leukemia cells, and normal B cells by promoting apoptosis. Taken together, these findings suggest that, in combination with other known rescue factors, autocrinely produced GM-CSF may contribute to normal and malignant B cell survival in vivo.

Autocrine Communication↗
PubMed2000

Kinetic studies of the mechanism of carbon-hydrogen bond breakage by the heterotetrameric sarcosine oxidase of Arthrobacter sp. 1-IN.

The reaction of heterotetrameric sarcosine oxidase (TSOX) of Arthrobactor sp. 1-IN has been studied by stopped-flow spectroscopy, with particular emphasis on the reduction of the enzyme by sarcosine. Expression of the cloned gene encoding TSOX in Escherichia coli enables the production of TSOX on a scale suitable for stopped-flow studies. Treatment of the enzyme with sulfite provides the means for selective formation of a flavin-sulfite adduct with the covalent 8alpha-(N(3)-histidyl)-FMN. Formation of the sulfite-flavin adduct suppresses internal electron transfer between the noncovalent FAD (site of sarcosine oxidation) and the covalent FMN (site of enzyme oxidation) and thus enables detailed characterization of the kinetics of FAD reduction by sarcosine using stopped-flow methods. The rate of FAD reduction displays a simple hyperbolic dependence on sarcosine concentration. Studies in the pH range 6.5-10 indicate there are no kinetically influential ionizations in the enzyme-substrate complex. A plot of the limiting rate of flavin reduction/the enzyme-substrate dissociation constant (k(lim)/K(d)) versus pH is bell-shaped and characterized by two macroscopic pK(a) values of 7.4 +/- 0.1 and 10.4 +/- 0.2: potential candidates for the two ionizable groups are discussed with reference to the structure of monomeric sarcosine oxidase (MSOX). The kinetic data are discussed with reference to potential mechanisms for the oxidation of amine molecules by flavoenzymes. Additionally, kinetic isotope effect studies of the rate of C-H bond breakage suggest that a ground-state quantum tunneling mechanism for H-transfer, facilitated by the low-frequency thermal motions of the protein molecule, accounts for C-H bond cleavage by TSOX. TSOX thus provides another example of C-H bond breakage by ground-state quantum tunneling, driven by protein dynamics [vibrationally enhanced ground-state quantum tunneling (VEGST)], for the oxidation of amines by enzymes.

Arthrobacter↗
PubMed2000

Susceptibility of Vespula vulgaris (Hymenoptera: vespidae) to generalist entomopathogenic fungi and their potential for wasp control.

The pathogenicity of Vespula vulgaris wasp workers and larvae to a range of fungi was determined. All fungi were isolated in New Zealand and included isolates from Vespula, known generalist insect pathogens, and isolates generally nonpathogenic to insects. Workers and larvae were highly susceptible to pathogenic isolates at high spore concentrations (>1.75 x 10(5) cfu/individual). Eight isolates, two of Metarhizium anisopliae, five of Beauveria bassiana, and one of Aspergillus flavus were pathogenic while a single isolate of M. flavouiride var. novazealandicum, Cladosporium sp., and Paecilomyces sp. were not. The transfer of spores between workers, and between workers and larvae, was also investigated using several different application methods. Transfer of spores occurred between treated and untreated individuals, and for some of the application methods sufficient spores were transferred to cause mortality of the nontreated individuals. These findings are related to the potential of fungi for the control of wasps.

Animals↗
PubMed2000

Long-term persistence of Coxiella burnetii in the host after primary Q fever.

After a primary infection Coxiella burnetii may persist covertly in animals and recrudesce at parturition to be shed in the products of conception and the milk. Similar latent persistence and recrudescence occurs in man: namely, infection of placenta, heart valve or mural endocardium, bone or liver. The numbers of organisms, their viability and cellular form, and the underlying organ sites of latent infection for the coxiella are obscure. During investigations of 29 patients with a chronic sequel to acute Q fever, the post-Q fever fatigue syndrome (QFS) [1-3], sensitive conventional and TaqMan-based PCR revealed low levels of C. burnetii DNA in blood mononuclear cells (5/29; 17%), thin needle liver biopsies (2/14; 14%) and, notably, in bone marrow aspirates (13/20; 65%). Irrespective of the ultimate significance of coxiella persistence for QFS, the detection of C. burnetii genomic DNA in bone marrow several years after a primary infection unveils a new pathological dimension for Q fever.

Bone Marrow↗
PubMed2000

Recurrent laryngeal nerve blockade in patients undergoing carotid endarterectomy under cervical plexus block.

We report two cases of recurrent laryngeal nerve blockade arising during carotid endarterectomy under cervical plexus anaesthesia. These nerve blocks were thought to be due to the instillation of local anaesthetic. The nerve block in one patient was responsible for a paroxysm of coughing which caused the formation of a large neck haematoma. We believe this to be the first report of local anaesthetic induced recurrent laryngeal nerve blockade leading to such a complication.

Aged↗
PubMed2000

A simple scale of Gorski's warning signs for relapse.

OBJECTIVE: Though it has enjoyed widespread popularity, Gorski's post-acute withdrawal syndrome (PAWS) model of relapse has been subjected to little scientific scrutiny. A scale to operationalize Gorski's 37 warning signs was developed and tested in a larger prospective study of predictors of relapse. Of central interest were: (1) whether the warning signs hypothesized by Gorski are interrelated in a meaningful single factor and (2) whether the hypothesized syndrome would accurately predict subsequent relapses. METHOD: A sample of 122 individuals (84 men) entering treatment for alcohol problems was followed at 2-month intervals for 1 year. The Assessment of Warning-signs of Relapse (AWARE) scale was administered at each assessment point, and the occurrence of both slips (any drinking) and relapses (heavy drinking) was monitored during each subsequent 2-month interval. Principal factor analysis was used to study the factor structure of the warning signs. RESULTS: Of the 37 warning signs, 28 clustered as a robust single factor with excellent internal consistency (Cronbach's alpha: 0.92-0.93). A conservative evaluation of test-retest stability across 2-month intervals estimated reliability at r = 0.80. After covarying for prior drinking status, clients' AWARE scores significantly predicted subsequent slips and relapses. Relapse rates for clients with highest AWARE scores, as projected by regression equations, were 33 to 46 percentage points higher than those for clients with lowest AWARE scores, after taking into account prior drinking status. CONCLUSIONS: This scale of Gorski's warning signs appears to be a reliable and valid predictor of alcohol relapses.

Adult↗
PubMed2000

A comparative study of root coverage obtained with an acellular dermal matrix versus a connective tissue graft: results of 107 recession defects in 50 consecutively treated patients.

Obtaining root coverage has become an important part of periodontal therapy. In this study, 2 surgical root coverage procedures were examined. The control group was treated with a coronally positioned pedicle graft combined with a connective tissue graft. The test group was treated with a coronally positioned pedicle graft combined with an acellular dermal matrix. There was no statistically significant difference in the mean root coverage obtained (96.2% control vs 95.8% test). There was a statistically significant reduction in probing depth (1.2 mm control vs 0.7 mm test) and increase in keratinized tissue (2.0 mm control vs 1.2 mm test) in both groups. The connective tissue graft produced a greater mean probing reduction and mean keratinized tissue increase than the acellular dermal matrix. However, this did not appear to be clinically significant. The results of both procedures were esthetically acceptable to the patients and clinically acceptable in all cases. In this study, the acellular dermal matrix and the connective tissue graft resulted in similar amounts of root coverage.

Adolescent↗
PubMed2000

Human histologic evaluation of a bone graft combined with GTR in the treatment of osseous dehiscence defects: a case report.

There are many possible goals and outcomes of periodontal surgical therapy, but the ultimate goal is regeneration. Since the definition of periodontal regeneration is histologic, it is difficult to document. The purpose of this study was to evaluate a technique that combined a bone graft and guided tissue regeneration (GTR) to see if regeneration occurred. Four teeth with dehiscence-type osseous defects that were scheduled for extraction were treated with bone grafts and GTR. During the surgical procedure, a notch was placed into the root at the apical extent of the calculus. The teeth were extracted with conservative block sections 7 months after the treatment. They were processed, sectioned, stained, and evaluated histologically. The results revealed that regeneration did not occur in any of the teeth treated. In 2 of the teeth new connective tissue attachment was formed. In these 2 teeth cementum could be seen in the notch with connective tissue fibers inserting into the cementum. In one of the teeth the junctional epithelium extended apical to the notch, while in 3 cases the epithelium stopped at or coronal to the notch. In this case report, no regeneration could be documented, but new attachment could be seen in 2 of the 4 teeth treated.

Alveolar Bone Loss↗
PubMed2000

Treatment of a cracked tooth with a resin-ionomer restoration and a connective tissue graft: a case report.

Treatment of a cracked tooth can be difficult and unpredictable. Quite often, the most predictable treatment possible is simply extraction. This is a case report of the treatment of a cracked tooth with a resin-ionomer restoration and a connective tissue with partial-thickness double pedicle graft. The crack was detected during a routine root coverage procedure using this type of graft. A resin-ionomer was used to repair the crack. Then, the root coverage procedure was completed. Complete root coverage was obtained, including the portion of the root that was repaired. The results remained stable and the tooth treated remained asymptomatic. Clinically, the treatment was a success.

Bicuspid↗
PubMed1999

Human histologic evaluation of root coverage obtained with a connective tissue with partial thickness double pedicle graft. A case report.

The use of a connective tissue graft combined with a pedicle graft has been proven an effective method to achieve root coverage. However, little is known about the histologic results in humans. A connective tissue with partial thickness double pedicle graft was performed on 2 teeth scheduled for extraction for prosthetic reasons. The procedures were clinically successful (100% and 83.3% root coverage). At 6 months postoperative, the teeth were extracted with conservative block sections and analyzed histologically. Two different healing patterns were seen. The first was characterized by a long junctional epithelial attachment that extended well beyond the original gingival margin and occasionally almost to the original bone level with minimal connective tissue adjacent to the tooth. The other pattern was a short junctional epithelium that stopped at the previously exposed root surface. In this pattern, there was predominately connective tissue adjacent to the tooth with some isolated areas of epithelium. No new bone or cementum was seen in any section. The use of a technique that combines a connective tissue graft with a pedicle graft can produce root coverage and a successful clinical result. However, the histological evaluation of this case report revealed that true regeneration was not seen in this study, only repair.

Alveolar Process↗
PubMed1999

Treatment of furcation defects with DFDBA combined with GTR: human histologic evaluation of a case.

The purpose of this study was to evaluate whether regeneration is possible in human furcation defects. Three molars with Class II furcation involvement were included in this study. A notch was placed in calculus in the furcation to serve as a reference point for histologic evaluation. The defects were treated with a demineralized freeze-dried bone allograft combined with a bioabsorbable membrane. At 6 months postoperative, the teeth were extracted with a small piece of tissue from the furcation area. The samples were then processed for histologic evaluation. Regeneration was found in 2 of the 3 samples. This study demonstrated that regeneration is possible in human furcation defects.

Absorbable Implants↗
PubMed1999

Successful root coverage: a human histologic evaluation of a case.

Connective tissue grafts combined with pedicle grafts (subepithelial grafts) have been shown to be effective in obtaining root coverage. Unfortunately, little is known about the histology of the results in humans. This is a case report of a tooth with a recession defect that was treated with a subepithelial graft. Complete root coverage was obtained. However, at 5 months postoperative the tooth had to be extracted because of a vertical root fracture. With the patient's permission, a small collar of tissue was removed with the tooth. The sample was processed and evaluated histologically. The results revealed areas of regeneration, with new bone, cementum, and connective tissue attachment coronal to the original gingival margin. No bone grafts or guided tissue regeneration membranes were used. This case report confirms that regeneration is possible with subepithelial grafts.

Adult↗
PubMed1998

Curriculum developments in Australasian anatomy departments.

This article explores the nature of the 12 anatomy departments in Australian and New Zealand medical schools. The transformation of these departments from medically oriented to science-oriented ones is examined. Contemporary trends in staffing, research emphases, and teaching methodologies are discussed, and recent developments in medical curricula reviewed. The relationship between medical courses and the teaching of science and health science students in Australasian departments is discussed. Finally, the state of anatomy as a discipline and possibilities for its future development are explored.

Anatomy↗