Rapid transition in the structure of a coral reef community: the effects of coral bleaching and physical disturbance

Coral reef communities are in a state of change throughout their geographical range. Factors contributing to this change include bleaching (the loss of algal symbionts), storm damage, disease, and increasing abundance of macroalgae. An additional factor for Caribbean reefs is the aftereffects of the epizootic that reduced the abundance of the herbivorous sea urchin, Diadema antillarum. Although coral reef communities have undergone phase shifts, there are few studies that document the details of such transitions. We report the results of a 40-month study that documents changes in a Caribbean reef community affected by bleaching, hurricane damage, and an increasing abundance of macroalgae. The study site was in a relatively pristine area of the reef surrounding the island of San Salvador in the Bahamas. Ten transects were sampled every 3-9 months from November 1994 to February 1998. During this period, the corals experienced a massive bleaching event resulting in a significant decline in coral abundance. Algae, especially macroalgae, increased in abundance until they effectively dominated the substrate. The direct impact of Hurricane Lili in October 1996 did not alter the developing community structure and may have facilitated increasing algal abundance. The results of this study document the rapid transition of this reef community from one in which corals and algae were codominant to a community dominated by macroalgae. The relatively brief time period required for this transition illustrates the dynamic nature of reef communities.     

The spectrum of abnormal patterns of gonadotropin-releasing hormone secretion in men with idiopathic hypogonadotropic hypogonadism: clinical and laboratory correlations

Several lines of evidence indicate that hypothalamic-pituitary-gonadal activity varies among men with idiopathic hypogonadotropic hypogonadism (IHH). To test the hypothesis that a spectrum of abnormalities of GnRH secretion underlies the syndrome of IHH, we characterized the patterns of GnRH-induced gonadotropin secretion during periods of frequent sampling in 50 consecutive men with IHH and contrasted them with those in 20 normal men. The largest group of IHH patients (n = 42) had no detectable LH or FSH pulsations and could be categorized into 2 subsets according to the presence or absence of evidence of spontaneous puberty. The most severely affected subset (n = 32), who recalled no history of puberty, had testes with a mean volume of 3.3 +/- 0.5 (+/- SEM) ml, with a prepubertal appearance on biopsy, and often were anosmic (n = 17). The second subset of apulsatile IHH men (n = 10) had histories of partial or complete spontaneous sexual development with subsequent isolated loss of sexual function, testes with a mean volume of 13.3 +/- 1.9 ml (P less than 0.01 compared to the first subset), a pubertal or adult appearance of the testes on biopsy, and an intact sense of smell. In a second group of IHH patients (n = 3), LH was secreted predominantly in a nighttime pattern similar to that of normal children during early puberty. These men were aged 18-24 yr, had a mean testicular volume of 10.5 +/- 2.3 ml, pubertal changes on testicular biopsy, and an intact sense of smell. A third group of IHH men (n = 4) had LH pulses of abnormally low amplitude. Only one patient in this group had a history of spontaneous sexual development. The mean testicular volume of these patients was 5.6 +/- 1.9 ml, and the testes appeared prepubertal (n = 3) or pubertal (n = 1) on biopsy. In addition to these groups, another patient had apparent LH pulsations and nearly normal amplitude, but the LH was bioinactive and appeared to consist chiefly of alpha-subunit. Testing of other anterior pituitary hormone functions did not distinguish IHH men from normal men. However, those IHH patients with some evidence of endogenous GnRH secretion had higher basal and stimulated serum PRL levels than IHH men without such evidence (P less than 0.05), suggesting an influence of GnRH on PRL secretion.     

Subclasses of antibodies to hepatitis B core antigen in chronic HBV infection: changes during treatment with alpha interferons and predictors of response

Response to interferon therapy in chronic hepatitis B virus (HBV) carriers is preceded by the appearance of IgM class anti-HBc (antibody to hepatitis B core antigen). The temporal relationship and magnitude of the IgM anti-HBc response is variable suggesting that the antibody is not directly involved in hepatocyte lysis, but is merely a marker of a changed state of immunity to the nucleocapsid proteins, induced by interferon. IgG 1, 2, 3, and 4 class anti-HBc did not change during therapy, but IgG 3 anti-HBc was significantly lower in responders than non-responders. IgG anti-HBc of all subclasses was absent in two Chinese HBV carriers. Lower than normal titres of anti-HBc (p less than 0.001) were detected in human immunodeficiency virus antibody positive (anti-HIV) HBV carriers. These data indicate the presence of altered immunity to the nucleocapsid antigens in these two types of chronic HBV carrier that are known to respond poorly to antiviral therapy.     

Oral mucosal precancer and cancer: A helpful discriminating clinical tool

The authors have collaborated with many colleagues in several countries in formulating a useful and practical clinical tool for evaluating oral mucosal findings on routine examination. Consideration of several factors including history, evolution of positive findings and clinical information allows placement of examination results into one of three categories which are graded by a color scheme along a spectrum of concerns (green to red, or no concern to serious concern). Afforded to the clinician is a straightforward grading system as a starting point for office end clinic use for all patients. Key words:Oral, precancer, cancer, clinical tool. The use of information technology in the area of clinical decision making is an increasing paradigm in the practice of medicine and dentistry. The technologies at hand within clinical decision support systems (CDSSs) have the potential to reduce clinical errors by incorporating systems for data analysis with that analysis used to measure and prevent adverse clinical outcomes, ultimately resulting in improved overall quality and efficiency in the delivery of care (1,2). Evidence-based medicine (EBM) - the practice of medicine based on the best available scientific evidence - can also improve clinical outcomes. The use of CDSSs to facilitate EBM therefore promises a substantial improvement in healthcare quality (3). EBM is based upon the scientific literature as the prime source of evidence, but should often be complemented by local, practice-based evidence for individual and site-specific clinical decision-making. However, lower levels of evidence and other sources such as Internet-based information should not be ignored (4). As stated recently in another context, “evidence-based recommendations are not a substitute for clinical judgment, and decisions about care must carefully consider and incorporate the clinical characteristics and circumstances of each individual patient” (5).Early diagnosis remains the essential aim of the primary care clinician as the single-most important contribution to help avoid the need for major and possibly radical treatment and thus improving chances of cure and retention of function and quality of life.We have therefore produced an “expert system” regarding evaluation of potentially malignant oral mucosal disease based upon considerable clinical experience on two continents, with advice from senior experienced colleagues. This was done in an effort to assist primary care clinicians in decision-making in relation to the identification and management of patients with possible oral cancer, based, in part on the previously published “RULE” for oral cancer diagnosis (lesions that are Red or white; Ulcerated; Lump; Extending >3 weeks) (6). This tool is based on the grading of general clinical observations along the green to red spectrum by the examining dental professional that should allow a degree of confidence within an office or clinic setting for identification of signs and habits related to oral cancer causation and evolution (Open in a separate windowThe straightforward tool or scheme we have developed, addresses essential considerations in measurement, recognition and prevention of oral cancer development and progression and the role played by the dental professional in recognition and appreciation of the historic and clinical factors in an all too common disease. Deviations from recognized clinical norms therefore, with either referral or direct action on the part of clinicians, thus can provide the best chance for reducing the frequency of errors and corresponding improvement of treatment outcomes. Finally, this approach could serve as a working template for all initial and future oral examinations, even in the absence of prior clinical indicators of mucosal abnormalities.     

Complement and cytokine response in acute Thrombotic Thrombocytopenic Purpura

Complement dysregulation is key in the pathogenesis of atypical Haemolytic Uraemic Syndrome (aHUS), but no clear role for complement has been identified in Thrombotic Thrombocytopenic Purpura (TTP). We aimed to assess complement activation and cytokine response in acute antibody‐mediated TTP. Complement C3a and C5a and cytokines (interleukin (IL)‐2, IL‐4, IL‐6, IL‐10, tumour necrosis factor, interferon‐γ and IL‐17a) were measured in 20 acute TTP patients and 49 remission cases. Anti‐ADAMTS13 immunoglobulin G (IgG) subtypes were measured in acute patients in order to study the association with complement activation. In acute TTP, median C3a and C5a were significantly elevated compared to remission, C3a 63·9 ng/ml vs. 38·2 ng/ml (P < 0·001) and C5a 16·4 ng/ml vs. 9·29 ng/ml (P < 0·001), respectively. Median IL‐6 and IL‐10 levels were significantly higher in the acute vs. remission groups, IL‐6: 8 pg/ml vs. 2 pg/ml (P = 0·003), IL‐10: 6 pg/ml vs. 2 pg/ml (P < 0·001). C3a levels correlated with both anti‐ADAMTS13 IgG (r_s = 0·604, P = 0·017) and IL‐10 (r_s = 0·692, P = 0·006). No anti‐ADAMTS13 IgG subtype was associated with higher complement activation, but patients with the highest C3a levels had 3 or 4 IgG subtypes present. These results suggest complement anaphylatoxin levels are higher in acute TTP cases than in remission, and the complement response seen acutely may relate to anti‐ADAMTS13 IgG antibody and IL‐10 levels.     

Marathon of eponyms: 23 Wegener granulomatosis

The use of eponyms has long been contentious, but many remain in common use, as discussed elsewhere (Editorial: Oral Diseases. 2009: 15; 185). The use of eponyms in diseases of the head and neck is found mainly in specialties dealing with medically compromised individuals (paediatric dentistry, special care dentistry, oral and maxillofacial medicine, oral and maxillofacial pathology and oral, oral and maxillofacial radiology and maxillofacial surgery) and particularly by hospital-centred practitioners. This series has selected some of the more recognized relevant eponymous conditions and presents them alphabetically. The information is based largely on data available from MEDLINE and a number of internet websites as noted below: the authors would welcome any corrections. This document summarizes data about Wegener granulomatosis.     

Biologics in oral medicine: principles of use and practical considerations

Oral Diseases (2012) 18, 525-536 Biologic therapies are relatively innovative treatments aimed at modulating lymphocytes or cytokines. There are currently three broad classes of biologic therapies, tumour necrosis factor-alpha inhibitors, lymphocyte modulators and interleukin inhibitors; all are increasingly used in the treatment of inflammatory immune-mediated conditions, and several have potential applications in oral medicine. Guidelines for their use in licensed indications (e.g. rheumatoid arthritis, psoriasis, inflammatory bowel disease) include recommendations and guidance for patient selection and subsequent monitoring with discussion of potential adverse effects. An understanding of these is important when managing patients receiving biologic therapy for systemic disease, and compliance is essential in any use in oral medicine. Key aspects of current guidance are presented with particular emphasis on their relevance to clinicians working within oral and maxillofacial medicine/pathology/surgery and in specialist practice.