Costimulatory molecules in human periodontal disease tissue

An immunoperoxidase technique was used to examine CD28, CD152, CD80 and CD86 positive cells in gingival biopsies from 21 healthy/gingivitis and 26 periodontitis subjects. The samples were placed into 3 groups (small, intermediate, large) according to the size of the infiltrate. The percent CD28+ T cells in the connective tissue infiltrates was highly variable with no differences between the healthy/gingivitis and periodontitis groups. While there was an increase in positive cells in intermediate infiltrates from both healthy/gingivitis (28.5%) and periodontitis (21.4%) patients compared with small infiltrates (8.6% and 11.8%, respectively), this was not significant, although the percent CD28+ T cells did increase significantly in tissues with increased proportions of B cells relative to T cells (p=0.047). A mean of less than 5% infiltrating T cells were CD152+ which was significantly lower than the mean percent CD28+ T cells in intermediate healthy/gingivitis lesions (p=0.021). The mean percent CD80+ and CD86+ B cells and macrophages was 1–7% and 8–16%, respectively, the difference being significant in intermediate healthy/gingivitis tissues (p=0.012). Analysis of these cells in relation to increasing numbers of B cells in proportion to T cells and also to macrophages, suggested that CD80 was expressed predominantly by macrophages while CD86 was expressed by both macrophages and B cells. Few endothelial cells expressed CD80 or CD86. Keratinocytes displayed cytoplasmic staining of CD80 rather than CD86 although the numbers of positive specimens in the healthy/gingivitis and periodontitis groups reduced with increasing inflammation. In conclusion, percentages of CD28, CD152, CD80 and CD86 did not reflect differences in clinical status. However, the percent CD28+ T cells increased with increasing size of infiltrate and with increasing proportions of B cells suggesting increased T/B cell interactions with increasing inflammation. The percent CD152+ cells remained low indicating that CD152 may not be involved in negative regulation of T cells in periodontal disease. CD80 and CD86 have been reported to promote Th1 and Th2 responses, respectively, and the higher percent CD86+ cells suggests a predominance of Th2 responses in both healthy/gingivitis and periodontitis tissues. Nevertheless, other factors including cytokines themselves and chemokines which modulate T cell cytokine profiles must be monitored to determine the nature of Th1/Th2 responses in periodontal disease.

Cytokines in periodontal disease: where to from here?

Numerous studies have attempted to elucidate the cytokine networks involved in chronic periodontitis, often with conflicting results. A variety of techniques were used to study cells in situ, cells extracted from gingival tissues, peripheral blood mononuclear cells, purified cell populations, and T cell lines and clones. Bacterial components, including sonicates, killed cells, outer membrane components, and purified antigens, have all been used to stimulate cells in vitro, making comparisons of cytokine profiles difficult. As it is likely that different cells are present at different disease stages, the inability to determine disease activity clinically is a major limitation of all these studies. In the context of tissue destruction, cytokines such as IL-1, IL-6 and IL-18 are likely to be important, as are their regulating cytokines IL-10 and IL-11. In terms of the nature of the inflammatory infiltrate, two apparently conflicting hypotheses have emerged: one based on direct observations of human lesions, the other based on animal experimentation and the inability to demonstrate IL-4 mRNA in gingival extracts. In the first of these, Th1 responses are responsible for the stable lesion, while in the second Th2 responses are considered protective. Using Porphyromonas gingivalis specific T cell lines we have shown a tendency for IFN-gamma production rather than LL-I or IL-10 when antigen is presented with peripheral blood mononuclear cells which may contain dendritic cells. It is likely that the nature of the antigen-presenting cell is fundamental in determining the nature of the cytokine profile, which may in turn open up possibilities for new therapeutic modalities.

Cell-surface proteoglycan expression by lymphocytes from peripheral blood and Gingiva in health and periodontal disease

Cell-surface proteoglycans are involved in lymphocyte migration and activation. This study investigated the expression of syndecan-1, syndecan-4, and glypican in peripheral blood lymphocytes and by lymphocytes in variously inflamed periodontal tissues. Gingival specimens from healthy, gingivitis, or chronic periodontitis sites were stained by means of antibodies against B- and T-lymphocytes and also syndecan-1, syndecan-4, and glypican. Syndecan-1 expression by peripheral blood mononuclear cells (PBMC) from healthy, gingivitis, and chronic periodontitis subjects was assessed by flow cytometry. Syndecan-1 was expressed by B-cells/plasma cells but not T-cells in both gingivitis and chronic periodontitis lesions, Both B-cells/plasma cells and T-cells in gingivitis and chronic periodontitis expressed syndecan-4. Glypican was expressed only by macrophages. Stimulation of PBMC with mitogens and growth factors modulated syndecan-1 expression in both the T- and B-cells. Thus, cell-surface proteoglycan expression by lymphocytes in periodontal inflammation is cell-type-specific and may be modulated by inflammation.

CDKN2A is not the principal target of deletions on the short arm of chromosome 9 in neuroendocrine (Merkel cell) carcinoma of the skin

The majority of small-cell lung cancers (SCLCs) express p16 but not pRb, Given our previous study showing loss of pRb in Merkel cell carcinoma (MCC)/neuroendocrine carcinoma of the skin and the clinicopathological similarities between SCLC acid MCC, we wished to determine if this was also the case in MCC, Twenty-nine MCC specimens from 23 patients were examined for deletions at 10 loci on 9p and I on 9p. No loss of heterozygosity (LO H) was peen in 9 patients including 2 for which tumour and cell line DNAs were examined. Four patients had LOH for all informative loci on 9p, Ten tumours showed more limited regions of loss on 9p, and from these 2 common regions of deletion were determined, Half of all informative cases had LOH at D95168, the most telomeric marker examined, and 3 specimens showed loss of only D9S168, A second region (InFNA-D9S126) showed L0H in 10(44%) cases, and case MCC26 showed LOH for only D9S126, implicating genes centromeric of the CDKN2A locus. No mutations in the coding regions of p16 were seen in 7 cell lines tested, and reactivity to anti-p16 antibody was seen in all Il tumour specimens examined and in 6 of 7 cell lines from 6 patients. Furthermore, all cell lines examined reacted with anti-p 14' antibody, These results suggest that neither transcript of the CDKN2A locus is the target of deletions on 9p in MCC and imply the existence of tumour-suppressor genes mapping both centromeric and telomeric of this locus. (C) 2001 Wiley-Liss, Inc.

Ross River virus transmission, infection, and disease: a cross-disciplinary review

Ross River virus (RRV) is a fascinating, important arbovirus that is endemic and enzootic in Australia and Papua New Guinea and was epidemic in the South Pacific in 1979 and 1980. Infection with RRV may cause disease in humans, typically presenting as peripheral polyarthralgia or arthritis, sometimes with fever and rash. RRV disease notificatïons in Australia average 5,000 per year. The first well-described outbreak occurred in 1928. During World War II there were more outbreaks, and the name epidemic polyarthritis was applied. During a 1956 outbreak, epidemic polyarthritis was linked serologically to a group A arbovirus (Alphavirus). The virus was subsequently isolated from Aedes vigilax mosquitoes in 1963 and then from epidemic polyarthritis patients. We review the literature on the evolutionary biology of RRV, immune response to infection, pathogenesis, serologic diagnosis, disease manifestations, the extraordinary variety of vertebrate hosts, mosquito vectors, and transmission cycles, antibody prevalence, epidemiology of asymptomatic and symptomatic human infection, infection risks, and public health impact. RRV arthritis is due to joint infection, and treatment is currently based on empirical anti-inflammatory regimens. Further research on pathogenesis may improve understanding of the natural history of this disease and lead to new treatment strategies. The burden of morbidity is considerable, and the virus could spread to other countries. To justify and design preventive programs, we need accurate data on economic costs and better understanding of transmission and behavioral and environmental risks.

Long-term risk stratification for survivors of acute coronary syndromes - Results from the long-term intervention with pravastatin in ischemic disease (LIPID) study

OBJECTIVES We developed a prognostic strategy for quantifying the long-term risk of coronary heart disease (CHD) events in survivors of acute coronary syndromes (ACS). BACKGROUND Strategies for quantifying long-term risk of CHD events have generally been confined to primary prevention settings. The Long-term Intervention with Pravastatin in Ischemic Disease (LIPID) study, which demonstrated that pravastatin reduces CHD events in ACS survivors with a broad range of cholesterol levels, enabled assessment of long-term prognosis in a secondary prevention setting. METHODS Based on outcomes in 8,557 patients in the LIPID study, a multivariate risk factor model was developed for prediction of CHD death or nonfatal myocardial infarction. Prognostic indexes were developed based on the model, and low-, medium-, high- and very high-risk groups were defined by categorizing the prognostic indexes. RESULTS In addition to pravastatin treatment, the independently significant risk factors included: total and high density lipoprotein cholesterol, age, gender, smoking status, qualifying ACS, prior coronary revascularization, diabetes mellitus, hypertension and prior stroke. Pravastatin reduced coronary event rates in each risk level, and the relative risk reduction did not vary significantly between risk levels. The predicted five-year coronary event rates ranged from 5% to 19% for those assigned pravastatin and from 6.4% to 23.6% fur those assigned placebo. CONCLUSIONS Long-term prognosis of ACS survivors varied substantially according to conventional risk factor profile. Pravastatin reduced coronary risk within all risk levels; however, absolute risk remained high in treated patients with unfavorable profiles. Our risk stratification strategy enables identification of ACS survivors who remain at very high risk despite statin therapy. CT Am Coil Cardiol 2001;38:56-63) (C) 2001 by the American College of Cardiology.

G2 phase cell cycle arrest in human skin following UV irradiation

The contribution of the short wavelength ultraviolet (UV) component of sunlight to the aetiology of skin cancer has been widely acknowledged, although its direct contribution to tumour initiation or progression is still poorly understood. The loss of normal cell cycle controls, particularly checkpoint controls, are a common feature of cancer. UV radiation causes both GI and G2 phase checkpoint arrest in vitro cultured cells. In this study we have investigated the cell cycle responses to suberythemal doses of UV on skin. We have utilized short-term whole organ skin cultures, and multi parameter immunohistochemical and biochemical analysis to demonstrate that basal and suprabasal layer melanocytes and keratinocytes undergo a G2 phase cell cycle arrest for up to 48 h following irradiation. The arrest is associated with increased p16 expression but no apparent p53 involvement. This type of organ culture provides a very useful model system, combining the ease of in vitro manipulation with the ability to perform detailed molecular analysis in a normal tissue environment.

Opportunities for the control of coronary heart disease in Australia

Objective: To estimate the number of coronary events that could be prevented in Australia each year by the use of preventive and therapeutic strategies targeted to subgroups of the population based on their levels of risk and need. Methods: Estimates of risk reduction from the published literature, prevalence estimates of elevated risk factor levels from the 1995 National Health Survey and treatment levels from the Australian collaborating centres in the World Health Organization's MONICA Project were used to calculate numbers of coronary events preventable among men and women aged 35-79 years in Australia. Results: Approximately 14,000 coronary events could be avoided each year if the mean level of cholesterol in the population was reduced by 0.5 mmol/L, smoking prevalence was halved and prevalence of physical inactivity was reduced to 25%. This represents a reduction in coronary events of about 40%. Even with less optimistic targets, a reduction of 20% could be attained, while the achievement of some internationally recommended targets could lead to almost 50% reduction. In the short term, aggressive medical treatment of people with elevated levels of risk factors and established coronary disease offers the greatest opportunity for reducing coronary events. Conclusion: A comprehensive approach to reduce levels of behavioural and biological risk factors and improve the use of effective treatment could lead to a large reduction in coronary event rates. In the long term, primary prevention - especially to reduce smoking, lower cholesterol levels and increase exercise - has the potential to reduce the population levels of risk and hence contain the national cost of coronary disease.

Veterinary drug delivery: Potential for skin penetration enhancement

A range of topical products are used in veterinary medicine. The efficacy of many of these products has been enhanced by the addition of penetration enhancers. Evolution has led to not only a highly specialized skin in animals and humans, but also one whose anatomical structure and skin permeability differ between the various species. The skin provides an excellent barrier against the ingress of environmental contaminants, toxins, and microorganisms while performing a homeostatic role to permit terrestrial life. Over the past few years, major advances have been made in the field of transdermal drug delivery. An increasing number of drugs are being added to the list of therapeutic agents that can be delivered via the skin to the systemic circulation where clinically effective concentrations are reached. The therapeutic benefits of topically applied veterinary products is achieved in spite of the inherent protective functions of the stratum corneum (SQ, one of which is to exclude foreign substances from entering the body. Much of the recent success in this field is attributable to the rapidly expanding knowledge of the SC barrier structure and function. The bilayer domains of the intercellular lipid matrices within the SC form an excellent penetration barrier, which must be breached if poorly penetrating drugs are to be administered at an appropriate rate. One generalized approach to overcoming the barrier properties of the skin for drugs and biomolecules is the incorporation of suitable vehicles or other chemical compounds into a transdermal delivery system. Indeed, the incorporation of such compounds has become more prevalent and is a growing trend in transdermal drug delivery. Substances that help promote drug diffusion through the SC and epidermis are referred to as penetration enhancers, accelerants, adjuvants, or sorption promoters. It is interesting to note that many pour-on and spot-on formulations used in veterinary medicine contain inert ingredients (e.g., alcohols, amides, ethers, glycols, and hydrocarbon oils) that will act as penetration enhancers. These substances have the potential to reduce the capacity for drug binding and interact with some components of the skin, thereby improving drug transport. However, their inclusion in veterinary products with a high-absorbed dose may result in adverse dermatological reactions (e.g., toxicological irritations) and concerns about tissue residues. These a-re important considerations when formulating a veterinary transdermal product when such compounds ate added, either intentionally or otherwise, for their penetration enhancement ability. (C) 2001 Elsevier Science B.V. All rights reserved.

Can increasing the viscosity of formulations be used to reduce the human skin penetration of the sunscreen oxybenzone?

The effect of adding thickening agents on the penetration of a sunscreen benzophenone-3 through epidermal and a high-density polyethylene membrane was studied using both very thick (infinite dose) and thin tin use) applications. Contradictory results were obtained. Thickening agents retard skin penetration, in a manner consistent with a diffusional resistance in the formulation, when applied as an infinite dose. In contrast, when applied as in thin (in use) doses, thickening agents promote penetration, most likely through greater stratum corneum diffusivity arising from an enhanced hydration by the thicker formulations. The two key implications from this work are (i) a recognition of the danger in the potential extrapolation of infinite dosing to in use situations, and (ii) to recognize that thicker formulations may sometimes enhance the penetration of other topical agents when applied in use.

New perspectives on the role of aldosterone excess in cardiovascular disease

1. Evidence from recent experimental and clinical studies suggests that excessive circulating levels of aldosterone can bring about adverse cardiovascular sequelae independent of the effects on blood pressure. Examples of these sequelae are the development of myocardial and vascular fibrosis in uninephrectomized, salt-loaded rats infused with mineralocorticoids and, in humans, an association of aldosterone with left ventricular hypertrophy, impaired diastolic and systolic function, salt and water retention causing aggravation of congestion in patients with established congestive cardiac failure (CCF), reduced vascular compliance and an increased risk of arrhythmias (resulting from intracardiac fibrosis, hypokalaemia, hypomagnesaemia, reduced baroreceptor sensitivity and potentiation of catecholamine effects). 2. These sequelae of aldosterone excess may contribute to the pathogenesis and worsen the prognosis of CCF and hypertension. 3. The heart and blood vessels may be capable of extra-adrenal aldosterone biosynthesis, raising the possibility that aldosterone may have paracrine or autocrine (and not just endocrine) effects on cardiovascular tissues. 4. The high prevalence of CCF, which is associated with secondary aldosteronism, and primary aldosteronism (PAL; recently recognized to be a much more common cause of hypertension than was previously thought) argue for an important role for aldosterone excess as a cause of cardiovascular injury. 5. The recognition of non-blood pressure-dependent adverse sequelae of aldosterone excess raises the question as to whether normotensive individuals with PAL, who have been detected as a result of genetic or biochemical screening among families with inherited forms of PAL, are at excess risk of cardiovascular events. 6. Provided that patients are carefully investigated in order to permit the appropriate selection of specific surgical (laparoscopic adrenalectomy for PAL that lateralizes on adrenal venous sampling) or medical (treatment with aldosterone antagonist medications) management and safety considerations for the use of aldosterone antagonists are kept in mind, the appreciation of a widening role for aldosterone in cardiovascular disease should provide a substantially better outlook for many patients with CCF and hypertension.