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Biomedical subjects

R Jackson

Publications and source records attributed to R Jackson.

At least 109 records · Page 6Linked to original sources
PubMed1999

The importance of technique in preventing postoperative sensitivity when placing bonded restorations.

This article has focused on what are thought to be some of the common causes of postoperative sensitivity following placement of adhesive restorations. Of course, there can be many other factors. There are an infinite number of roads or combinations of roads that won't get dentists where they want to go. However, there is a specific road or roads, when taken carefully in the proper sequence, that will predictably get dentists to their destinations. The same is true for bonding. Adhesive dentistry is by no means difficult, but it is exacting. If the rules are understood and followed precisely, dentists will find the results are well worth the effort.

Dental Bonding↗
PubMed1999

Looking ahead...

Explore the source record for details and available documents.

Computer Systems↗
PubMed1998

CC-chemokines enhance the replication of T-tropic strains of HIV-1 in CD4(+) T cells: role of signal transduction.

This study demonstrates that several CC-chemokines, including those that inhibit entry and replication of macrophage-tropic strains of HIV, increase the replication of T cell (T)-tropic strains in CD4(+) T cells. Enhancement of T-tropic HIV replication is observed at early stages of replication, requires signaling through inhibitory guanine nucleotide-binding regulatory (Gi) proteins, and is associated with increased cell surface colocalization of CD4 and the T-tropic HIV coreceptor CXCR4. These findings may further our understanding of the factors that influence the replication and spread of T-tropic strains of HIV in vivo and suggest that the use of cell signaling CC-chemokines as therapeutic agents for the purpose of limiting HIV replication in vivo should be approached with caution.

Anti-HIV Agents↗
PubMed1998

Natural killer cells from human immunodeficiency virus (HIV)-infected individuals are an important source of CC-chemokines and suppress HIV-1 entry and replication in vitro.

Macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and RANTES (regulated on activation, normal T cell expressed and secreted), which are the natural ligands of the CC-chemokine receptor CCR5, inhibit replication of MT-2- negative strains of HIV-1 by interfering with the ability of these strains to utilize CCR5 as a coreceptor for entry in CD4(+) cells. The present study investigates the capacity of natural killer (NK) cells isolated from HIV-infected individuals to produce CC-chemokines and to suppress HIV replication in autologous, endogenously infected cells as well as to block entry of MT-2-negative HIV into the CD4(+) T cell line PM-1. NK cells freshly isolated from HIV-infected individuals had a high number of mRNA copies for MIP-1alpha and RANTES. NK cells produced significant amounts of RANTES, MIP-1alpha, and MIP-1beta constitutively, in response to stimulation with IL-2 alone and when they were performing their characteristic lytic activity (K562 killing). After CD16 cross-linking and stimulation with IL-2 or IL-15 NK cells produced CC-chemokines to levels comparable to those produced by anti-CD3-stimulated CD8(+) T cells. Furthermore, CD16 cross-linked NK cells suppressed (49-97%) viral replication in cocultures of autologous CD8/NK-depleted PBMC to a degree similar to that of PHA or anti-CD3-stimulated CD8(+) T cells. In 50% of patients tested, NK-mediated HIV suppression could be abrogated by neutralizing antibodies to MIP-1alpha, MIP-1beta and RANTES; in contrast, CD8(+) T cell-mediated suppression was not significantly overcome upon neutralization of CC-chemokines. Supernatants derived from cultures of CD16 cross-linked NK cells stimulated with IL-2 or IL-15 dramatically inhibited entry of a MT-2-negative strain of HIV, BaL, in the CD4(+)CCR5(+) PM-1 T cell line. These data suggest that activated NK cells may be an important source of CC-chemokines in vivo and may suppress HIV replication by CC-chemokine-mediated mechanisms in addition to classic NK-mediated lytic mechanisms.

CD3 Complex↗
PubMed1998

Natural killer activating receptors trigger interferon gamma secretion from T cells and natural killer cells.

Proliferation of human CD4+ alphabeta T cells expressing a natural killer cell activating receptor (NKAR) has been shown to be enhanced, particularly in response to low doses of antigen, if the target cells present appropriate human class I major histocompatibility complex (MHC) molecules. Here, we show that NKAR also enhance proliferation and killing of target cells by subsets of CD8+ alphabeta and CD8+ gammadelta T cells, as well as by NK cells. Strikingly, interferon gamma secretion from all of these types of lymphocytes was markedly increased by interaction of the NKAR with their MHC class I ligands, independently of enhancement of proliferation. Thus, the recognition of class I MHC molecules by NKAR on both T cells and NK cells may provide a regulatory mechanism that affects immune responses through the secretion of interferon gamma and possibly other cytokines. It represents a signal for cytokine secretion alternative and/or augmentative to that through the T cell receptor.

CD56 Antigen↗
PubMed1998

Cardiovascular disease risk factors in 65-84 year old men and women: results from the Auckland University Heart and Health Study 1993-4.

AIM: To describe the distribution of the major cardiovascular risk factors among older men and women in the Auckland region, New Zealand. METHODS: Means and prevalences of the major cardiovascular risk factors were estimated for non-Maori, non-Pacific Islands men and women in the age groups 65-74 and 75-84 years using data from the 1993-4 survey of the University of Auckland Heart and Health Study, a cross-sectional, population-based study of cardiovascular risk factors. RESULTS: 996 people aged 65-84 years participated, with men and women and the two ten-year age groups almost equally represented. Fewer than half engaged in regular leisure time physical activity; around 35% were overweight (BMI 25-30) and 10% were obese (BMI > 30). Total mean cholesterol levels were higher in women and 46% of women had a cholesterol level > or = 6.5 mmol/L compared with only 17% of men. However, total cholesterol:HDL ratios were higher among men. Age and sex differences in blood pressure were small. Around 50% had raised blood pressure (BP > 150/90) or were currently on antihypertensive medication; only 8% smoked; around 6% were diabetic. Almost 8% had three or all of four major modifiable cardiovascular risk factors (elevated blood pressure, total cholesterol:HDL ratio > or = 6.5, current smoking and physical inactivity). CONCLUSIONS: These results are broadly comparable to those from other Western populations. Differences between 65-74 and 75-84 year age groups are few but important differences in cholesterol, smoking and physical activity between older men and women are noted. These findings indicate that there is considerable potential for prevention of cardiovascular disease among older people.

Aged↗
PubMed1998

Whither dermatology. Thoughts generated after holding a dermatology clinic on Baffin Island.

In February 1998, I spent 3 days at the regional hospital at Iqaluit (Figure 1) on Baffin Island, 2578 km north of New York, NY (Figure 2). Two thirds of the patients here were Inuit, many having been flown in from outposts hundreds of miles away where daily continuing care was provided by nurses, with only occasional visits by physicians. One third of the patients had moderate to severe atopic dermatitis, displaying a great variety of morphological patterns. One tenth had alopecia areata totalis or universalis. About one half could not speak English, and there was no patient information literature available in their language; many believed that I was going to cure them. The challenges that the management of these conditions presented in this population were formidable; the hands-on effort required to care for these patients in a straight-forward and honest manner was great. By the end of several 12-hour days, with a noon break each day to give an in-service lecture, I felt exhausted but satisfied.

Canada↗
PubMed1998

Fine-needle aspiration cytology of extranodal lymphoma.

The assessment of lymphoproliferative disorders using fine-needle aspiration (FNA) cytology may be problematic particularly when organs other than lymph node are involved. In this report we have reviewed 26 consecutive FNA specimens from superficial extranodal sites which were reported as diagnostic or suggestive of malignant lymphoma. The aspirates were obtained from skin or subcutaneous tissue (ten cases), thyroid (five cases), salivary gland (five cases), breast (four cases), neck, and pharynx (one case each). Ancillary studies including immunocytochemistry, in situ hybridisation to detect immunoglobulin light chain mRNA expression, and polymerase chain reaction for analysis of immunoglobulin heavy chain gene rearrangement were performed in 20, 12, and 7 cases, respectively. Clinicopathologic correlation confirmed the diagnosis of lymphoma in 25/26 aspirates. Nine of the 14 patients whose initial presentation was with an extranodal mass were considered to have primary lymphomas of mucosa-associated lymphoid tissue (MALT) type. In contrast, ten of 11 patients with recurrent extranodal disease had primary nodal type lymphomas. There was one false-positive diagnosis, a neck mass misinterpreted cytologically as B-cell lymphoma which was ultimately shown to be a branchial cyst. FNA cytology supported by appropriate ancillary investigations provides accurate diagnosis in most cases of extranodal lymphoma.

Adult↗
PubMed1998

Changing sex ratio in the United States, 1969-1995.

OBJECTIVE: To determine if the sex ratio of live births in the United States has changed during the 27 years from 1969 through 1995. DESIGN: Regression analysis of secular trends in sex ratios. SETTING: Population-based data. PATIENT(S): Liveborn infants in the United States 1969-1995. MAIN OUTCOME MEASURE(S): Sex of liveborn infant. RESULT(S): The sex ratio (number of male births divided by number of female births) declined significantly among whites during the 27 years under study. Among black newborns, the sex ratio significantly increased during the same time period. CONCLUSION(S): These secular trends could not be explained by changing maternal or paternal age, or by changing proportions of specific birth orders. Possible explanations for the observed changes in sex ratio include random fluctuations in sex ratio over time, changes in demographic characteristics of the population (other than the characteristics controlled for in this analysis), and changes in frequency or timing of intercourse. Environmental exposures are unlikely to account for the observed trends.

Black People↗
PubMed1998

Race and survival after out-of-hospital cardiac arrest in a suburban community.

STUDY OBJECTIVE: To determine whether race, when controlled for income, is an independent predictor of survival to hospital discharge after out-of-hospital cardiac arrest (OHCA). METHODS: Prospective OHCA data were collected over 4 years (1991-1994) from a convenience sample of OHCA patients transported to nine hospitals in three suburban counties. Race was determined from hospital and vital statistics records. The average household income was identified from ZIP codes and used as a marker of socioeconomic status. Demographic data and known predictors of survival were compared between blacks and whites. A logistic regression analysis was used to assess the association between race, income, and survival. RESULTS: Of the 1,690 patients, 223 (13%) were blacks and 1,467 (87%) were whites. Average household income was less for blacks than for whites ($40,225 versus $46,193; P < .001), but both populations were affluent by national standards (national percentile ranks were 73% and 88%, respectively). The populations were no different in percentage of witnessed arrests (57% versus 61%; P = .465). Blacks were younger (mean +/- SD, 62 +/- 16 versus 68 +/- 15 years; P < .001); less frequently received bystander CPR (11% versus 20%; P = .002); less often had ventricular tachycardia or ventricular fibrillation (37% versus 50%; P < .001); and had a shorter advanced life support call-response interval (median, 4 versus 6 minutes; P < .001). The odds ratio for survival (white/black) was .931 (95% confidence interval, .446 to 1.945). CONCLUSION: Race was not found to predict adverse OHCA outcomes in this affluent population.

Black or African American↗
PubMed1998

Which elderly patients should be considered for anti-hypertensive treatment? An evidence-based approach.

BACKGROUND: The evidence-based approach to medical care involves the explicit use of evidence on the magnitude of the effects of interventions to inform diagnostic and treatment decisions. This article critiques current mainstream guidelines on the management of hypertension in the elderly (aged 60 years and over) and presents an alternative evidence-based approach. METHODS: Three major national and international guidelines for the management of hypertension from the United Kingdom (UK), the United States (US) and from a joint World Health Organisation/International Society of Hypertension (WHO/ISH) Working Party were appraised and the evidence on which they were based was reviewed. The relevant evidence was also assessed to determine the likely magnitude of risks and benefits of anti-hypertensive treatment in older people and an alternative approach to making treatment decisions, based on the New Zealand guidelines for the management of hypertension, is described. RESULTS: Hypertension management guidelines from the UK, US and WHO/ISH made similar recommendations about which elderly patients should be treated, although there were some ambiguities in their advice. Treatment recommendations were based primarily on blood pressure levels which were set at about 160 mm Hg systolic and/or 90 mm Hg diastolic. The threshold levels were based mainly on the cut-off blood pressure levels used in randomised trials of anti-hypertensive drug treatment, rather than the estimated magnitude of treatment benefit. Each of the guidelines acknowledged the important effect of associated cardiovascular disease (CVD) risk factors on the likely benefits of treatment, but did not expand on the magnitude of this effect. No patient-specific estimates of the likely absolute benefits of treatment were provided in any of the guidelines. In contrast the New Zealand guidelines for the management of hypertension recommend the use of explicit estimates of absolute CVD risks and benefits to inform treatment decisions. They were designed to provide practitioners with estimates of the likely absolute risk of CVD in patients with different risk factor profiles and with estimates of the absolute benefits of treatment. The New Zealand guidelines recommend that drug treatment be considered in patients with a 5-year risk of CVD of about 10-15% or more; approximately 25 patients with a 10-15% risk would require treatment for 5 years to prevent one CVD event. As elderly patients are generally at higher absolute CVD risk than younger people, the New Zealand recommendation give priority to the treatment of older patients. In order to take account of differences in life expectancy and the medical costs of caring for elderly people, absolute risk-based guidelines can be improved by incorporating potential years of life gained from treatment and the cost-effectiveness of treatment expressed as $/quality adjusted life years gained. Preliminary analyses indicate that the cost-effectiveness of treatment is generally greatest in patients in their 60s and early 70s. Treatment in younger people is not usually very cost-effective because of their low absolute risk of CVD and the cost-effectiveness of treatment in people over about 75 years declines because of the increasing cost of non-CVD morbidity. CONCLUSIONS: The explicit assessment of absolute CVD risks and likely treatment benefits in patients with hypertension can usefully inform treatment decisions and provide a more rational basis for initiating therapy than blood pressure levels alone. This approach highlights the generally greater CVD risk and potential treatment benefits in older compared with younger hypertensive patients. The absolute risk-based approach can be further enhanced by providing decision makers with patient-specific data on the potential life years gained from treatment and its cost-effectiveness. (ABSTRACT TRUNCATED)

Age Distribution↗
PubMed1998

The determinants of fat intake in a multi-ethnic New Zealand population. Fletcher Challenge--University of Auckland Heart and Health Study Management Committee.

BACKGROUND: The New Zealand diet is high in total and saturated fat and this is likely to be contributing to the increasing prevalence of obesity and relatively high rates of coronary heart disease in New Zealand. The identification of subgroups with a high-fat intake will enable nutrition-related public health strategies to be better targeted. METHODS: Subjects from two surveys were included in the study: 7574 employees from a large multinational workforce survey and 2447 people aged 35-84 years selected from a stratified random sample of the electoral roll in central Auckland. Fat and saturated fat intake were assessed by short questionnaire which gave a dietary fat habits (DFH) score and supplemented by a six-item food frequency questionnaire. RESULTS: The DFH scores were higher in males than in females at all ages, and there was an inverse relationship with age which was stronger for males. Age-adjusted scores showed significantly higher DFH scores for Maori than for Europeans. Lower socioeconomic status was associated with higher DFH scores in males. Current smoking and heavy drinking (in males) were associated with significantly higher DFH scores after controlling for socioeconomic status. The results of the limited food frequency questionnaire supported the trends in DFH scores. CONCLUSIONS: The subgroups with high total and saturated fat intakes which should be a priority for public health action are young and middle-aged males, Maori and lower socioeconomic status males. The clustering of high-fat intake with smoking and heavy drinking should be considered when developing preventative strategies.

Adult↗
PubMed1998

A multi-center prospective study of the CD Spinal System in patients with degenerative disc disease.

This paper reports on 41 patients available for 24 months' follow-up who were entered into a prospective, multi-center study of the safety and efficacy of using the CD Spinal System (Sofamor Danek) containing pedicle screws and rods to treat adult patients with degenerative disc disease. All of these patients were implanted with only the CD Spinal System in an attempt at fusing four levels or less with autogenous bone graft only. At 24 months the results were compared to literature controls in regard to fusion, pain, function, neurological status, and complications. For function and neurological status, the CD Spinal System results were found to be statistically equal to and for fusion, pain, and complications, found to be statistically better than the noninstrumented literature controls with the same disease condition and demographics.

Adult↗
PubMed1998

Rapid reduction in coronary risk for those who quit cigarette smoking.

The objective of this study was to determine the rate of the decline in risk of a major coronary event after quitting cigarette smoking. It was a population-based case-control study of men and women aged 35 to 69 years in Newcastle, Australia, and men and women aged 35 to 64 years in Auckland, New Zealand, between 1986 and 1994. Cases were 5,572 people identified in population registers of coronary events and controls were 6,268 participants in independent community-based risk factor prevalence surveys from the same study populations. There was a rapid reduction in risk after quitting cigarette smoking. The risk of suffering a major coronary event for men who were current cigarette smokers was 3.5 (95% CI 3.0-4.0) times higher than the risk for never smokers but this fell to 1.5 (95% CI 1.1-1.9) for men who had quit for 1-3 years. Women who were current cigarette smokers were 4.8 (95% CI 4.0-5.9) times more likely to suffer a major coronary event than never smokers and this fell to 1.6 (95% CI 1.0-2.5) for women who had quit for 1-3 years. Those who had quit cigarette smoking for 4-6 years or more had a similar risk to never smokers. These results reinforce the importance of smoking cessation. The public health message is that the benefit of giving up smoking occurs rapidly.

Adult↗
PubMed1998

A split-mouth placebo-controlled study to determine the effect of amorphous calcium phosphate in the treatment of dentine hypersensitivity.

Many treatments for dentine hypersensitivity are formulated to directly or indirectly occlude the open dentinal tubules associated with the condition. Combining solutions of calcium chloride and potassium phosphate can result in the precipitation of amorphous calcium phosphate. Such a system applied to exposed dentine could occlude dentinal tubules and reduce sensitivity. The aims of this study using a placebo control were to assess the therapeutic value of amorphous calcium phosphate in dentine hypersensitivity and provide further information on the apparently natural improvement in the condition frequently observed in clinical trials. 38 subjects with dentine hypersensitivity affecting 1 tooth in each left and right sides of the jaws were recruited into this split mouth, randomised, double-blind study. At baseline, sensitivity was scored by the subjects on a 0-10 visual apologue scale after tactile, cool and cold water and evaporative stimulation of the test teeth. Active and control, water, solutions were then applied by a 2nd clinician. After 24 h, subjects returned for rescoring. On days 7 and 14, subjects were again rescored and the treatments reapplied. Further follow-up appointments for rescoring were on days 21, 28, 56 and 84. Plaque scores also were recorded from test teeth at each visit. Overall sensitivity decreased considerably and to a similar degree in test and control teeth with no consistent significant treatment difference. Plaque scores also decreased through the study period. It is concluded that either the amorphous calcium phosphate was without therapeutic effect or the activity was masked by the placebo response in the control teeth.

Administration, Topical↗