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Biomedical subjects

R J Harris

Publications and source records attributed to R J Harris.

At least 55 records · Page 3Linked to original sources
PubMed1998

Cytokine dysregulation in the post-Q-fever fatigue syndrome.

The post-Q-fever fatigue syndrome (QFS) (inappropriate fatigue, myalgia and arthralgia, night sweats, changes in mood and sleep patterns) follows about 20% of laboratory-proven, acute primary Q-fever cases. Cytokine dysregulation resulting from chronic immune stimulation and modulation by persistence of Coxiella burnetii cells or their antigens is hypothesized. We studied cytokine release patterns of peripheral blood mononuclear cells (PBMC) stimulated with various ligands in short-term culture, from 18 patients with active QFS, and 27 controls: six with resolving QFS, five who had had acute primary Q-fever without subsequent QFS, eight healthy Q-fever vaccinees and eight healthy subjects without Q-fever antibody. Conditioned media (CM) from PBMC stimulated in short-term culture with Q-fever antigens, PHA or measles antigen (as an unrelated antigen) were assayed for IL-2, IL-4, IL-5, IL-6, IL-10 and IFN gamma by AgEIA, and for IL-1 and TNF alpha/beta by bioassay. Aberrant cytokine release patterns were observed with PBMC from QFS patients when stimulated with Q-fever antigens: an accentuated release of IL-6 which was significantly [p = 0.01, non-parametric one-way analysis of variance (ANOVA)] in excess of medians for all four control groups. With IL-2, the number of responders in the active QFS group was decreased relative to control groups (Fisher's exact test, p = 0.01) whereas the number of IFN gamma responders was increased (Fisher's exact test, p = 0.0008). Significant correlations were observed between concentrations of IL-6 in CM, total symptom scores, and scores for other key symptoms.

Acute Disease↗
PubMed1998

Root coverage with a connective tissue with partial thickness double pedicle graft and an acellular dermal matrix graft: a clinical and histological evaluation of a case report.

Root coverage can be achieved by many techniques. In this case report a patient was treated with a connective tissue with partial thickness double pedicle graft, which resulted in complete root coverage. However, 6 days postsurgery the patient developed a bleeding problem from the palatal donor area. For this reason, a unique approach was used to treat the next area needing root coverage. The procedure combined an acellular dermal matrix and a coronally positioned pedicle. The procedure was used to treat 3 defects. Complete root coverage was obtained on 2 of the 3 defects. The third was covered to within 1 mm of the cemento-enamel junction (CEJ). Histology showed similar results with a connective tissue graft and an acellular dermal matrix. Verhoeff's staining demonstrated that the acellular dermal matrix was incorporated into the gingival tissue. This case report demonstrated that acceptable results can be obtained with the connective tissue with partial thickness double pedicle graft and the acellular dermal matrix combined with a coronally positioned pedicle, both clinically and histologically.

Connective Tissue↗
PubMed1998

A comparison of 2 root coverage techniques: guided tissue regeneration with a bioabsorbable matrix style membrane versus a connective tissue graft combined with a coronally positioned pedicle graft without vertical incisions. results of a series of consecutive cases.

Root coverage procedures have become an important part of periodontal therapy. The purpose of this study was to compare 2 techniques, 1) guided tissue regeneration (GTR) with a bioabsorbable polylactic acid softened with citric acid ester membrane and 2) the connective tissue graft combined with a coronally positioned pedicle graft without vertical incisions. The GTR procedure produced a mean root coverage of 92.3% and the connective tissue graft combined with a coronally positioned pedicle graft, 95.0%. This difference was not statistically significant. Both procedures produced similar reductions in recession depth, recession width, and probing depth. The connective tissue graft combined with a coronally positioned pedicle graft resulted in a greater increase in the amount of keratinized tissue. Based on this study, both procedures can result in statistically similar amounts of mean root coverage, but the results are not identical. In most cases, the connective tissue with coronally positioned pedicle graft produced a more bulky result than guided tissue regeneration. Therefore, the procedures are not interchangeable.

Adult↗
PubMed1998

A clinical evaluation of an allograft combined with a bioabsorbable membrane versus an alloplast/allograft composite graft combined with a bioabsorbable membrane. 100 consecutively treated cases.

The purpose of this study was to evaluate and compare the clinical effectiveness of 2 surgical techniques in treating periodontal defects. Both techniques involved tetracycline treatment of a root planed root, grafting the osseous defect with a bone graft, and placement of a bioabsorbable membrane. In group A, the bone graft was a mix of demineralized freeze-dried allograft, tetracycline, and porous hydroxyapatite and in group B, the bone graft was a mix of demineralized freeze-dried allograft and tetracycline. There was a statistically significant increase in recession (group A, 0.7 mm; group B, 0.6 mm), decreases in probing depth (group A, 6.1 mm; group B, 5.6 mm), and gains in attachment levels (group A, 5.4 mm; group B, 5.0 mm). There were no statistically significant differences between the results for either group. The defects associated with furcations and those that were not associated with furcations had similar results, except for the percent attachment gain. Smoking and age (> or =60 years old) could not be associated with results. Defects with > or =10 mm probing depths (PD) had greater PD reductions (group A, 7.7 mm; group B, 7.1) and attachment gains (group A, 6.6 mm; group B, 6.4 mm) than the defects with probing depths less than 10 mm (probing reduction group A, 4.8 mm; group B, 4.5 mm; attachment gain group A, 4.4 mm; group B, 4.0 mm). Both surgical procedures improved the clinical situation. However, neither technique seemed to offer a statistical advantage over the other. The inclusion of porous hydroxyapatite did not improve or diminish the results.

Adult↗
PubMed1998

Treatment of a previously placed autogenous masticatory mucosa graft (free gingival graft). A case report.

The autogenous masticatory mucosa graft (free gingival graft) has been used to treat various mucogingival conditions. Unfortunately, the esthetics of the procedure are often less than ideal. This case report examines the treatment of an unesthetic free gingival graft. The goal was to create a result so that it was impossible to tell there had ever been a free gingival graft or any surgery performed to correct a problem. To achieve this goal, 3 periodontal plastic surgical procedures were utilized and a crown was placed. This integration of multiple surgical procedures and prosthetics produced an outstanding result.

Connective Tissue↗
PubMed1998

Evaluation of the lysosome-associated membrane protein LAMP-2 as a marker for lysosomal storage disorders.

For many lysosomal storage disorders, presymptomatic detection, before the onset of irreversible pathology, will greatly improve the efficacy of current and proposed therapies. In the absence of a family history, presymptomatic detection can be achieved only by a comprehensive newborn screening program. Recently we reported that the lysosome-associated membrane protein LAMP-1 was increased in the plasma from approximately 70% of individuals with lysosomal storage disorders. Here we report on the evaluation of a second lysosome-associated membrane protein, LAMP-2, as a marker for this group of disorders. The median concentration of LAMP-2 in the plasma of healthy individuals was 1.21 mg/L, fourfold higher than the median LAMP-1 concentration (0.31 mg/L). LAMP-2 was increased in >66% of patients with lysosomal storage disorders, and the increases coincided with increased LAMP-1 concentrations. The reference intervals for LAMP-1 and LAMP-2 in blood spots taken from newborns were 0.20-0.54 mg/L (n = 1600) and 0.95-3.06 mg/L (n = 1600), respectively. A high correlation was observed between the concentrations of LAMP-1 and LAMP-2 in both control and affected individuals. The higher concentrations of LAMP-2, relative to LAMP-1, in plasma make LAMP-2 an attractive marker; however, the final selection will be dependent on the availability of new diagnostic markers and their ability to detect disorders currently not identified by LAMP-2.

Adolescent↗
PubMed1997

Cerebellar hypoplasia and frontal lobe cognitive deficits in disorders of early childhood.

A developmental chronometry hypothesis of early brain damage is suggested in which regions of the brain with a protracted course of postnatal development will be more vulnerable than earlier maturing areas to deleterious effects of early insult and, therefore, may become common sites of abnormality across many disorders originating in early childhood. Initial investigations of the cerebellum and frontal lobes are presented using MRI and neuropsychological measures. Planimetric measures of the cerebellar vermis (lobuli I-V and VI-VII) and pons, and neuropsychological frontal lobe measures were obtained from high functioning individuals with autism (A), survivors of acute lymphoblastic leukemia (ALL) with brain sequelae following radiation and chemotherapy, and from rigorously selected healthy controls (C). The neuropsychological results were clustered according to functions commonly related to frontal brain, posterior brain, and left and right hemispheres. The A and ALL groups, as compared to C, yielded modest but consistently reduced MRI measures for vermal lobuli I-V and VI-VII. Hypoplasia of lobuli VI-VII was more marked than I-V. Performance on neuropsychological tests for frontal lobe functions was generally depressed in both groups, with more severe deficits in A. Between-group differences in verbal, visual-spatial, and emotional-social skills are discussed. The cerebellar and frontal brain deficits that are present in both clinical groups (A and ALL) may be common to other developmental and acquired disorders of early childhood. Such joint manifestation of cerebellar and frontal lobe abnormalities is in agreement with the concept of cerebellar significance for the development of higher cognitive functions.

Adolescent↗
PubMed1997

A clinical evaluation of guided tissue regeneration with a bioabsorbable matrix membrane combined with an allograft bone graft. A series of case reports.

THE PURPOSE OF THIS STUDY was to evaluate the clinical effectiveness of a surgical technique in treating periodontal defects. The technique combined tetracycline treatment of a root planed root, grafting of the osseous defect with a demineralized freeze-dried bone allograft combined with tetracycline and the placement of a bioabsorbable matrix membrane, made of polylactic acid softened with citric acid ester. Thirty defects were treated in 27 patients. Statistically significant changes, as a result of the surgical procedure, were observed in marginal recession (mean: 0.5 mm), probing depth reductions (mean: 5.7 mm), and attachment level gain (mean: 5.2 mm). No statistically significant difference existed between the results in the furcation and non-furcation groups. The defects with probing depths > or = 10 mm had a greater mean probing depth reduction (7.4 mm) and mean attachment level improvement (7.2 mm) than the defects with < 10 mm probing depths (probing depth reduction 4.5 mm and attachment level gain 3.9 mm). The proposed surgical procedure seemed to be an effective method to treat periodontal defects.

Adult↗
PubMed1997

A comparative study of root coverage obtained with guided tissue regeneration utilizing a bioabsorbable membrane versus the connective tissue with partial-thickness double pedicle graft.

Obtaining predictable root coverage has become an important part of periodontal therapy. The purpose of this study was to compare two techniques of obtaining root coverage. The two techniques were the connective tissue with partial-thickness double pedicle graft and guided tissue regeneration with a bioabsorbable polylactic acid softened with citric acid ester membrane. The connective tissue with partial-thickness double pedicle graft had a mean root coverage of 97.1%, and the guided tissue regeneration procedure produced a mean root coverage of 75.1%. This difference was not statistically significant. Additionally, it was the goal of this study to determine if the thickness of the tissue near the defect was a factor in root coverage. Thickness of the tissue was not a factor with the connective tissue with partial-thickness double pedicle graft. The thin areas had a mean root coverage of 100%, while the others had a mean root coverage of 95.9%. This difference was not statistically significant; however, the thickness of the tissue was a factor in root coverage success in the guided tissue regeneration procedure. The thin areas treated with guided tissue regeneration had a mean root coverage of 26.7%, while the others had a mean root coverage of 95.9%. This difference was statistically significant. The results of this study demonstrate that root coverage is possible with both procedures. However, when the tissue in the area of the defect is relatively thin, the connective tissue with partial-thickness double pedicle graft will produce greater root coverage. When treating defects with tissue that is not thin, similar amounts of root coverage can be obtained with both procedures.

Absorption↗
PubMed1997

Creeping attachment associated with the connective tissue with partial-thickness double pedicle graft.

The occurrence of creeping attachment has been documented with epithelialized autogenous masticatory mucosa grafts (free gingival grafts) and suggested in other root coverage techniques. The purpose of this study was to examine whether or not creeping attachment occurred after a connective tissue with partial-thickness double pedicle graft had been performed. This study examined 22 defects, in 19 patients, treated where less than complete root coverage was obtained at 4 weeks postoperative. Creeping attachment occurred in 21 of the 22 defects (95.5%), in 18 of the 19 patients (94.7%). Complete root coverage occurred in 17 of the 22 defects (77.3%), in 15 of 19 patients (78.9%). The mean creeping attachment obtained was 0.8 mm. Additionally, it was the goal of this study to see if any factor could be associated with creeping attachment. This study did not find any factors that could be associated with the amount of creeping attachment seen. Creeping attachment seems to occur commonly, but complete root coverage is not predictable.

Adult↗
PubMed1997

A comparison of two techniques for obtaining a connective tissue graft from the palate.

Connective tissue grafts have become an important part of periodontal reconstructive surgery. There are several techniques available to harvest a suitable connective tissue graft. In this study, two techniques for obtaining a connective tissue graft were compared. The techniques examined were the free gingival knife method and the parallel incisions method. The connective tissue grafts were used in a root coverage procedure: the connective tissue with partial thickness double pedicle graft technique. No statistically significant difference in the mean root coverage was detected when comparing the results produced by these graft harvesting techniques (98.3% to 98.7%). Root coverage of 100% was obtained in 84.2% of the cases treated with the free gingival graft knife method and in 93.3% of the cases treated with the parallel incisions method. Additionally, the parallel incisions method produced less patient discomfort, a smaller wound at 1 week postoperative, a more uniform graft, and was easier to use clinically. Based on this study, the parallel incision method meets more of the goals of an ideal technique for harvesting a connective tissue graft than the free gingival graft knife method.

Adolescent↗
PubMed1996

N-aryl-3,3,3-trifluoro-2-hydroxy-2-methylpropanamides: KATP potassium channel openers. Modifications on the western region.

A subset of antiandrogen compounds, the N-aryl-3,3,3-trifluoro-2-hydroxy-2-methylpropanamides 1, were found to activate ATP sensitive potassium channels (KATP) and represent a new class of potassium channel openers (PCOs). A structure-activity relationship was carried out on the western region of this series with the goal of obtaining an activator of the ATP sensitive potassium channel suitable for use in the treatment of urge urinary incontinence. In particular three large 4-(N-aryl) substituents, the (N-phenyl-N-methylamino)sulfonyl, benzoyl, and 4-pyridylsulfonyl moieties, yielded non-antiandrogen, KATP potassium channel openers (39, 41, and 64, respectively) that are bladder selective in an in vivo rat model that simultaneously measures bladder contractions, heart rate, and blood pressure. Substitutions of the aryl rings of 41 and 64 gave several derivatives that also display selectivity in the in vivo rat model; however, none appear to offer a substantial advantage over 41 and 64. The PCO activity of 41 and 64 resides in the (S)-(-) enantiomers. ZD6169, 41(S), has been selected into development for the treatment of urge urinary incontinence.

Amides↗
PubMed1996

Magnetic resonance imaging of adrenocortical adenomas in childhood: correlation with computed tomography and ultrasound.

There are few descriptions of the magnetic resonance (MR) appearance of hyperfunctioning adrenocortical tumours, particularly those occurring in childhood. We studied five patients, two girls and three boys, aged 6-14.3 years, presenting with clinical syndromes of adrenocortical hyperfunction. The diagnoses were Cushing's syndrome (n = 2), virilisation (n = 2), and Conn's syndrome (n = 1). Biochemical features suggested an adrenal lesion in each case. MR and ultrasound were performed in all five cases, with CT in four. Each patient had a functional adrenal tumour secreting either cortisol, androgens or aldosterone alone, or a combination of cortisol, androgens and oestradiol. The histological diagnosis was adenoma in four cases and tumour of indeterminate nature in one case. MR clearly showed the tumours (diameter 1.0-7.5 cm), all the lesions being of high signal intensity relative to liver on T2-weighted sequences. CT revealed an adrenal mass in each of the four patients scanned, three of which enhanced after intravenous contrast medium injection. The multiplanar imaging of MR allowed better distinction from adjacent structures and also demonstrated an unenlarged contralateral adrenal gland. In the patient with a 1-cm Conn's adenoma the lesion was more easily seen on MR than CT. Ultrasound showed the four larger tumours but was unable to visualise the contralateral adrenal or the Conn's adenoma. In conclusion, the MR appearances of four adrenocortical adenomas and one indeterminate tumour in children are described. MR has been found to be at least equal to CT in the detection of these tumours, with some possible advantages. Both techniques are superior to ultrasound.

Adenoma↗
PubMed1996

Effect sizes and p values: what should be reported and what should be replicated?

Despite publication of many well-argued critiques of null hypothesis testing (NHT), behavioral science researchers continue to rely heavily on this set of practices. Although we agree with most critics' catalogs of NHT's flaws, this article also takes the unusual stance of identifying virtues that may explain why NHT continues to be so extensively used. These virtues include providing results in the form of a dichotomous (yes/no) hypothesis evaluation and providing an index (p value) that has a justifiable mapping onto confidence in repeatability of a null hypothesis rejection. The most-criticized flaws of NHT can be avoided when the importance of a hypothesis, rather than the p value of its test, is used to determine that a finding is worthy of report, and when p approximately equal to .05 is treated as insufficient basis for confidence in the replicability of an isolated non-null finding. Together with many recent critics of NHT, we also urge reporting of important hypothesis tests in enough descriptive detail to permit secondary uses such as meta-analysis.

Psychophysiology↗
PubMed1996

An information processing view of framing effects: the role of causal schemas in decision making.

People prefer a sure gain to a probable larger gain when the two choices are presented from a gain perspective, but a probable larger loss to a sure loss when the objectively identical choices are presented from a loss perspective. Such reversals of preference due to the context of the problem are known as framing effects. In the present study, schema activation and subjects' interpretations of the problems were examined as sources of the framing effects. Results showed that such effects could be eliminated by introducing into a problem a causal schema that provided a rationale for the reciprocal relationship between the gains and the losses. Moreover, when subjects were freed from framing they were consistently risk seeking in decisions about human life, but risk averse in decisions about property. Irrationality in choice behaviors and the ecological implication of framing effects are discussed.

Adult↗