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Biomedical subjects

R F Wilson

Publications and source records attributed to R F Wilson.

At least 109 records · Page 6Linked to original sources
PubMed1994

Effectiveness of oral hygiene with and without root planing in treating subjects with chronic periodontitis.

The extent to which patients with chronic periodontitis could improve their condition by oral hygiene without instrumentation was investigated. Ten subjects were assessed, instructed in a subgingivally-directed oral hygiene technique (OH) twice a week until plaque was present at less than 20% of sites on two occasions and reassessed after 6 weeks when half the mouth was root planed. A final assessment took place after a further 6 weeks. At six weeks the mean number of sites with bleeding on probing (BOP) was significantly reduced (P < 0.001), the percentage of sites with BOP falling from 59% to 34%. In addition, an increase in gingival recession (P < 0.001) was accompanied by a reduction in mean probing depths (PD) (P < 0.05). The mean percentage reduction in sites with BOP was greatest for sites with probing depths less than 4 mm at baseline but even at sites with PD of 6 mm or more the mean BOP reduced from 81% to 57% of sites. Root planing at 6 weeks resulted in further significant reductions at 12 weeks in both BOP (to 10% of all sites) and in PD (P < 0.001), but there was little further change for the sites receiving OH alone. There was some evidence that this adjunctive effect of root planing was also present at sites with a PD less than 4 mm at baseline and at sites without retention factors at or below the gingival margin. The results indicate that patients with chronic periodontitis can improve their periodontal condition by OH alone even in deep pockets.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Comparison of the effect of fluoride and non-fluoride toothpaste on tooth wear in vitro and the influence of enamel fluoride concentration and hardness of enamel.

The effect of the presence of fluoride in toothpaste on tooth wear was investigated in extracted human premolar teeth collected from two geographic areas with different fluoride concentrations in the public water supply. Nine teeth from each area were divided bucco-lingually into matched pairs and subjected to a wear regime in vitro. The regime consisted of 5 minutes immersion in 6% citric acid buffered at pH 3.5, followed by 200 cycles of linear tooth-brushing in a slurry of either a fluoride or a non-fluoride toothpaste, the whole process repeated 720 times. Teeth collected from subjects in Birmingham (public water supply fluoridated at 1 ppm) had a higher fluoride concentration in the surface enamel (P < 0.01) and greater hardness (P < 0.001) than teeth collected from subjects in London (non-fluoridated water supply). The results showed that less wear was produced in the presence of the fluoride toothpaste than in the presence of the non-fluoride toothpaste with an otherwise identical formulation (P < 0.001), and that the amount of tooth wear in vitro was not significantly affected by differences in fluoride concentration and hardness of enamel.

Dental Enamel↗
PubMed1994

The effect of restorative materials on the wear of human enamel.

The wear of human dental enamel against amalgam, Concise composite, SR-Isosit Inlay/Onlay composite, Vitadur-N glazed porcelain, unglazed IPS Empress ceramic, and enamel (control) was investigated by use of a modified stress cycling machine. Testing was carried out in water and in citric acid (pH 4) and the enamel-material couples were subjected to 25,000 cycles of wear with a maximum load of 40 N. Tooth profile reduction was measured at baseline and at 5000 cyclic intervals with a computer image analysis program. The depth of the wear scars on material specimens was analyzed with a profilometer. All materials produced increased enamel wear in acid. Vitadur-N glazed porcelain was found to be the most destructive to human dental enamel, and this was closely followed by Empress and enamel.

Acrylic Resins↗
PubMed1994

Metastatic adenocarcinoma in a recent burn scar.

Neoplastic lesions arising in recent burn scars are apparently quite rare and we could find no report of such an occurrence in the literature. Nevertheless we recently treated a patient with a metastatic adenocarcinoma from the lung in a 3-month-old burn scar.

Adenocarcinoma↗
PubMed1994

Regional differences in lymphocyte function following resuscitated hemorrhagic shock.

Although it is well known that hemorrhagic shock causes immunosuppression, there have been few attempts to define these changes in the various immune compartments. Accordingly, male rats were bled into severe hemorrhagic shock for 60 minutes (mean arterial pressure 35 +/- 5 mm Hg). Twenty-four hours following resuscitation, splenic, mesenteric, and peripheral lymphocytes were harvested for cell population analysis and mitogen stimulation assays. Cell marker analysis revealed no changes in B-cell or T-cell subpopulations in any immune compartment after shock. The splenic and peripheral lymphocytes showed marked depression of mitogen-induced stimulation after shock. In contrast, mesenteric lymphocyte responses to both T-cell and B-cell mitogens were not depressed after shock. Regional variability in mitogen responses after shock occur without change in B-cell or T-cell subpopulations in any immune compartment tested. The mechanism or mechanisms involved warrant further investigation.

Animals↗
PubMed1994

End-diastolic volume versus pulmonary artery wedge pressure in evaluating cardiac preload in trauma patients.

OBJECTIVE: To evaluate the relative accuracy of right ventricular end-diastolic volume index (RVEDVI) and pulmonary artery wedge pressure (PAWP) for determining cardiac preload. METHODS: A modified pulmonary artery catheter was used to determine RVEDVI, PAWP, and CI 238 times in 32 trauma patients. RESULTS: The initial mean values included cardiac index (CI) = 3.4 +/- 1.3 L/min/m2, PAWP = 14.8 +/- 6.6 mm Hg, and RVEDVI = 99 +/- 40 mL/m2. Cardiac index correlated better with RVEDVI (r = 0.6440; p < 0.001) than with PAWP (r = 0.1068) or CVP (r = 0.1604). In 84 studies in 19 patients, the PAWP was high (19+ mm Hg) in spite of an RVEDVI that was low (< 90 mL/m2) in 22 (26%) or mid-range (90-140 mL/m2) in 49 (58%) of these. In addition, in 12 studies a high RVEDVI (> 140 mL/m2) existed with a relatively low PAWP (< 12 mm Hg). Thus, in 83 (35%) of the studies, PAWP provided information different from the RVEDVI. Of 65 instances in which preload was increased, CI "responded" (> or = 20%) in 26 (40%). The incidence of a response was not affected by the PAWP; however, responses with a RVEDVI of < 90, 90-140, or > 140 mL/m2 were 64%, 27%, and 0 (p < 0.001). CONCLUSION: The RVEDVI more accurately predicted preload recruitable increases in CI than did the PAWP.

Adult↗
PubMed1994

The AAPT1 gene of soybean complements a cholinephosphotransferase-deficient mutant of yeast.

Aminoalcoholphosphotransferases (AAPTases) utilize diacylglycerols and cytidine diphosphate (CDP)-aminoalcohols as substrates in the synthesis of the abundant membrane lipids phosphatidylcholine and phosphatidylethanolamine. A soybean cDNA encoding an AAPTase that demonstrates high levels of CDP-choline:sn-1,2-diacylglycerol cholinephosphotransferase activity was isolated by complementation of a yeast strain deficient in this function and was designated AAPT1. The deduced amino acid sequence of the soybean cDNA showed nearly equal similarity to each of the two characterized AAPTase sequences from yeast, cholinephosphotransferase and ethanolaminephosphotransferase (CDP-ethanolamine:sn-1,2-diacylglycerol ethanolaminephosphotransferase). Moreover, assays of soybean AAPT1-encoded enzyme activity in yeast microsomal membranes revealed that the addition of CDP-ethanolamine to the reaction inhibited incorporation of 14C-CDP-choline into phosphatidylcholine in a manner very similar to that observed using unlabeled CDP-choline. Although DNA gel blot analysis suggested that AAPT1-like sequences are represented in soybean as a small multigene family, the same AAPT1 isoform isolated from a young leaf cDNA library was also recovered from a developing seed cDNA library. Expression assays in yeast using soybean AAPT1 cDNAs that differed only in length suggested that sequences in the 5'leader of the transcript were responsible for the negative regulation of gene activity in this heterologous system. The inhibition of translation mediated by a short open reading frame located 124 bp upstream of the AAPT1 reading frame is one model proposed for the observed down-regulation of gene activity.

Amino Acid Sequence↗
PubMed1994

Preliminary characterisation of antigens recognised by monoclonal antibodies raised to Porphyromonas gingivalis and by sera from patients with periodontitis.

A panel of 15 monoclonal antibodies (MAbs) was raised to Porphyromonas gingivalis and used to characterise the antigens which they recognise by ELISA, immunofluorescence (IF), Western blotting and patient serum inhibition studies. All the MAbs were specific for P. gingivalis and did not recognise 24 other species. Eight MAbs gave bright ring-like staining patterns against the majority of serotypes of P. gingivalis tested by IF. The antibodies could be grouped into 5 different antigen recognition profiles on Western blotting, and ELISA indicated that 8 of them bound to a capsular extract. Five antibodies bound to antigenic determinants recognised by sera from patients with periodonitis and 4 of these (1A1, 2B/H9, 3B1, 7D5) bound to a P. gingivalis 47kDa protease preparation on Western blotting. These antibodies are potentially useful for the purification and characterisation of biologically active components of P. gingivalis that are recognised by sera from patients with periodontitis.

Adult↗
PubMed1994

Antibacterial activity of potential retrograde root filling materials.

The antibacterial activity of potential retrograde root filling materials was assessed using the agar diffusion inhibitory test. A light-cured glass ionomer cement (Vitrebond) and three reinforced zinc oxide-eugenol cements (Kalzinol, IRM & ethoxybenzoic acid [EBA] cement) were compared with amalgam, a commonly used retrograde root filling material. Forty standardized pellets of each material were produced. Fresh, and materials aged for 1 week in sterile distilled water, were placed on blood agar plates inoculated with Streptococcus anginosus (milleri) or Enterococcus faecalis. At intervals of 3, 7 and 10 days, the presence and diameter of zones of inhibition were recorded. The diameter of the zones of inhibition increased with time for all materials, both fresh and aged. Vitrebond had the most pronounced antibacterial activity against both bacteria, producing the largest zone of inhibition, followed by Kalzinol. Amalgam had no measurable inhibitory effect whether aged or fresh, regardless of the period of exposure. There was no statistically significant difference in the response of the two bacteria. However, there were statistically significant differences between materials, period of exposure, and between fresh and aged materials (P < 0.001). Kalzinol, IRM and EBA cement were more antibacterial when aged than fresh, whilst Vitrebond was more active when fresh. Vitrebond was the only material for which the diameter of the zones of inhibition was reduced after ageing but it had the most pronounced antibacterial activity compared with the other materials. The antibacterial activity of the materials was ranked in the following order: Vitrebond > Kalzinol > (IRM = EBA cement) > amalgam.

Analysis of Variance↗
PubMed1994

Biological properties of IRM with the addition of hydroxyapatite as a retrograde root filling material.

The effect of adding 10% & 20% hydroxyapatite (HAP) on the antibacterial activity and cytotoxicity of IRM (Intermediate Restorative Material) when used as a retrograde root filling was compared with amalgam, a commonly used material. The antibacterial activity was assessed using the agar diffusion inhibitory test. Forty standardized pellets of each material were produced. Fresh materials, and materials aged for 1 week in sterile distilled water, were placed on blood agar plates inoculated with Streptococcus anginosus (milleri) or Enterococcus faecalis. The presence and diameter of zones of inhibition were recorded at intervals of 3, 7 and 10 days. There was no statistically significant overall difference in the response of the two bacteria tested. However, there were statistically significant overall differences in diameters of the zones of inhibition related to different materials, period of exposure and ageing of materials (P < 0.001). The diameter of the zones of inhibition increased with time for all materials, fresh and aged. IRM and both the HAP-modified forms produced large zones of inhibition. Amalgam produced no measureable zones of inhibition whether aged or fresh, regardless of period of exposure and was different from the other materials (P < 0.001). The cytotoxicity was assessed using the Millipore filter method. Ten standardized pellets of each material were produced and aged by storage in sterile distilled water for 72 h. Ten filters were included as controls. Amalgam produced a consistent cytotoxic score of 1, and the difference between amalgam and the other materials was statistically significant (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

3T3 Cells↗
PubMed1994

Cytotoxicity of potential retrograde root-filling materials.

The cytotoxicity of potential retrograde root-filling materials was assessed using the Millipore filter method. A light-cured glass ionomer cement, Vitrebond (VB), and three reinforced zinc oxide-eugenol cements, Kalzinol, IRM and ethoxybenzoic acid (EBA) cement, were compared with amalgam. Twenty standardized pellets of each material, 10 fresh and 10 aged by storage in sterile distilled water for 72 h were produced. Ten filters were included as controls: five filters with a cell monolayer, but without test specimens, and another five without cells but with test specimens. Fresh IRM exhibited the most pronounced cytotoxic effect and the difference was statistically significant compared with all the other materials. There was no statistically significant difference between fresh VB, Kalzinol, EBA cement and amalgam. When aged, Kalzinol was the most cytotoxic and the difference was statistically significant compared with the other materials. Aged IRM was the second most cytotoxic material and this too was statistically different. The cytotoxicity of VB, EBA, and amalgam did not differ significantly from one another.

3T3 Cells↗
PubMed1994

Trauma in patients with pre-existing cardiac disease.

More than 30% of trauma patients over 55 years of age have pre-existing diseases and by the time these patients reach 65 years of age, 13.7% of them will have hypertension, 9.2% will have chronic obstructive pulmonary disease (COPD), 6.3% will have diabetes, and 5.6% will have coronary artery disease (CAD). By the age of 75 years, 12.9% will have CAD, and the most frequent cause of death in elderly individuals living for more than 48 hours after trauma will be sepsis and/or CAD. To obtain the best results in patients with pre-existing cardiac disease, one must have a high suspicion of its presence and aggressively treat the patient to prevent hypotension and hypoxemia. Early monitoring and optimization of cardiac output, organ delivery, and oxygen consumption are particularly important in elderly trauma patients if they require general anesthesia or ICU care.

Aged↗
PubMed1994

Pre-existing peripheral arterial disease in trauma.

Patients with PAD tend to be much older physiologically than patients of the same chronologic age who do not have vascular disease. In addition, patients with vascular disease in one system tend to have vascular disease in other areas of the body, especially in the vessels supplying the heart and brain. Many also have pre-existing pulmonary and renal dysfunction. Even if trauma does not involve any diseased vessels, the hypotension that often occurs with major injuries may cause thrombosis of vessels that have a critical degree of stenosis. If a diseased vessel is injured, direct reconstruction may be difficult or impossible and a bypass may have to be performed. If this is not feasible in a severely injured lower extremity, early amputation may be the safest option. Even if the initial trauma is handled very well, patients with vascular disease tend to have an increased incidence of complications and death, and such patients require careful intensive care unit monitoring for at least 2 to 3 days.

Carotid Artery Diseases↗
PubMed1993

Impact of tissue plasminogen activator and heparin versus heparin alone on quantitative coronary angiographic findings in myocardial infarction. The Toronto Tissue Plasminogen Activator Trial Study Group.

The influence of tissue plasminogen activator (t-PA) and heparin versus heparin alone on anatomic characteristics of patent infarct-related coronary arteries and the development of these angiographic descriptors in coronary arteries that remain patent during the hospital course was examined in 108 patients who participated in a placebo-controlled trial of recombinant tissue-type plasminogen activator in acute myocardial infarction. Coronary angiography was performed 18 +/- 6 hours after treatment in 47 patients (group A) and at 10 days in 61 patients (group B). Quantitative coronary angiography of the infarct-related lesion was performed, and luminal irregularity was quantitated with an ulceration index. Of the 47 patients in group A, 7 (29%) treated with placebo had Thrombolysis in Myocardial Infarction grade 2 or 3 perfusion, whereas 18 (78%) treated with t-PA had grade 2 or 3 (p < 0.001); there was no difference between patients who had grade 2 or 3 perfusion in group B (placebo 59% vs t-PA 75%). In group A, at 10 days, the luminal area of the infarct artery had increased from 0.59 +/- 0.11 to 0.9 +/- 0.24 mm2 and from 0.75 +/- 0.16 to 1.31 +/- 0.39 mm2 for placebo- and t-PA-treated patients, respectively (p < 0.04). There was no change in the ulcerative index over time in either placebo- or t-PA-treated patients. It is concluded that early after infarction, t-PA produces marked and rapid improvement in overall patency as compared with heparin, although this difference was attenuated at 10 days because of spontaneous recanalization in the placebo group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

HECs: are they evaluating their performance?

Although the incidence and composition of HECs has been well characterized, little is known about how HECs assess their performance. In order to describe the incidence of HEC self-evaluation, the methods HECs use to evaluate their performance, and the characteristics of HECs that influence self-evaluation, we surveyed the readers of Hospital Ethics. 290 HECs in 45 U.S. states, the District of Columbia, Puerto Rico and three Canadian provinces, completed questionnaires. Of the 241 HECs included in the data analysis, 97.9% had performed some self-evaluation. Responding committees largely made formative rather than summative evaluations and appeared to evaluate performance in light of their own objectives rather than basing assessments on specific structural, process, and outcome measures of quality. Responding committees used certain evaluation criteria more extensively than others--among these, the number of participants and staff knowledge of the service provided--with the choice of criteria differing with the function being evaluated. Eight characteristics of HECs influenced the probability of self-evaluation, including age, number of beds and meetings, the existence of a mission statement, and a budget. The presence of certain characteristics made HECs six times more likely to evaluate their performance than HECs without the characteristic.

Canada↗
PubMed1993

Screening diabetic transplant candidates for coronary artery disease: identification of a low risk subgroup.

Coronary artery disease is the major cause of death in diabetic renal transplant recipients. Because one-third of diabetic transplant candidates have clinically silent coronary artery disease, many transplant centers recommend coronary angiography prior to transplantation. However, angiography is expensive and may precipitate acute renal failure. Therefore, we developed a noninvasive screening algorithm to identify patients at low risk for coronary artery disease (CAD), defined as one or more coronary stenoses > or = 50% diameter. We performed coronary angiography in 141 consecutive asymptomatic Caucasian type I diabetic renal transplant candidates. Fourteen of 16 patients age 45 or older had CAD. One hundred and twenty-five patients under age 45 were randomly divided into two groups. Ninety patients were used to identify clinical factors significantly associated with CAD which included smoking for five or more pack years, nonspecific ST-T wave changes on electrocardiogram, and diabetes duration 25 years or longer. The screening algorithm, "CAD is predicted in diabetic transplant candidates under age 45 with any of the above risk factors," was then tested in the remaining 35 patients and in 35 additional patients. In these 70 patients, the algorithm had a sensitivity of 97% and a negative predictive accuracy of 96%. We conclude that coronary angiography should be recommended to Caucasian type I diabetic renal transplant candidates age 45 or older because of the high probability of disease. In patients younger than 45 without a smoking history, ST-T wave changes on EKG, or diabetes longer than 25 years, the likelihood of CAD is low and angiography can be avoided.

Adult↗