An Analysis of Rare Carcinoid Tumors: Clarifying These Clinical Conundrums

Carcinoid tumors are distinct neuroendocrine neoplasms with characteristic histological, clinical, and biological properties. Though commonly associated with the gastrointestinal tract and bronchopulmonary system, a substantial number of these tumors originate in less common anatomical sites and can range from indolent, unrecognized entities to highly active, metastatic secretory tumors. Their presentation within unfamiliar locations often results in clinical confusion, and they persist as unrecognized lesions, subjecting patients to delayed, inappropriate, or ineffective treatment. The authors reviewed 13,715 carcinoid tumors identified by three consecutive registries of the National Cancer Institute (NCI) from 1950 to 1999, focusing on the anatomic sites accounting for less than one percent of all carcinoids. In addition, data from the worlds literature published on carcinoid tumors within these particular anatomic locations were then analyzed with respect to incidence, clinical presentation, symptoms, diagnostic evaluation, microscopic and immunohistochemical findings, treatment strategies, and prognosis. The primary organs in which carcinoids are most commonly mistaken for some of the more conspicuous endemic tumors include the esophagus, pancreas, liver, biliary tract, gallbladder, and Meckels diverticulum, as well as within the pelvic and otolaryngeal organs and the breast. In general, the highest proportion of rare carcinoids was identified in the gastrointestinal (GI) tract, with the ovary as the single most affected extra-GI site. Tumors with the worst prognosis were those that involved the pancreas (37.5%: 5-year survival) and those in the cervix (12-33%: 3-year survival). While gastrointestinal carcinoids have become a more recognized entity and thus more amenable to identification, similar lesions are often not considered in other sites and have often either been overlooked or misdiagnosed. Widespread reports of their occurrence in rare locations warrants attention. The diminution of the likelihood of inadvertently neglecting these often benign, indolent neoplasms that are well known to metastasize if unaddressed would represent an important advance. Familiarity with such unusual sites of origin will facilitate appropriate recognition and characterization of such tumors, allowing for timely intervention.     

How 'clean' must a cavity be before restoration?

The metabolic activity in dental plaque, the biofilm at the tooth surface, is the driving force behind any loss of mineral from the tooth or cavity surface. The symptoms of the process (the lesion) reflect this activity and can be modified by altering the biofilm, most conveniently by disturbing it by brushing with a fluoride-containing toothpaste. The role of operative dentistry in caries management is to restore the integrity of the tooth surface so that the patient can clean. Thus, the question, 'how clean must a cavity be before restoration?' may be irrelevant. There is little evidence that infected dentine must be removed prior to sealing the tooth. Leaving infected dentine does not seem to result in caries progression, pulpitis or pulp death. However, some of the bacteria survive. What is their fate and if they are not damaging, why is this?     

The Relationship of a <Emphasis Type="Italic">Helicobacter heilmannii</Emphasis> Infection to the Mucosal Changes in Abattoir and Laboratory Pig Stomach

Purpose A pig ulcer model in which ulceration is reproducibly induced in the pars oesophagea (a tongue of the oesophageal squamous epithelium that extends into the pig stomach) by bile duct ligation (BDL) was used in this study to determine whether Helicobacter heilmannii (Hh) is a predisposing factor in the ulceration of this region. The infection with Hh and its relationship to ulceration and mucus integrity was examined.Methods We microscopically investigated the occurrence of spontaneous pars oesophageal ulceration in 33 pigs from a local abattoir and 5 pigs nurtured in pens in our surgical laboratory (JSM). Further groups of 5 and 6 JSM pigs underwent a sham operation and a BDL, respectively. Giemsa staining was used to detect Hh and purified mucin was characterized by gel filtration.Results Ten of 33 and 2 of 5 of the stomachs of abattoir and JSM pigs, respectively, were positive for Hh by Giemsa stain. Three of the 33 abattoir pigs showed ulceration in the pars oesophagea and none of these was Hh-positive. All six of the bile duct-ligated pigs showed ulceration in the pars but only 2 of these were Giemsa-positive. Only 8 of 33 of the abattoir pigs had 50% large polymeric mucin that was eluted in the void/excluded volume of a Sepharose 2B column.Conclusions There was no consistent correlation between an infection of the pig stomachs by Hh, an ulceration of the pars oesophagea, and mucin degradation. There was a significant difference between the percentage of polymeric mucin from the abattoir pigs and that of the JSM group (P < 0.003), the JSM group vs sham-operated pigs (P < 0.011), and JSM vs BDL pigs (P < 0.0005), but there appeared to be no association between the infectivity with Hh and mucin degradation.     

Adenovirus type 37 binds to cell surface sialic acid through a charge-dependent interaction

Most adenoviruses use the coxsackie-adenovirus receptor (CAR) as a major cellular receptor. We have shown recently that adenovirus types 8, 19a, and 37, which are the major causes of epidemic keratoconjunctivitis, use sialic acid rather than CAR as a major cellular receptor. The predicted isoelectric point of the receptor-interacting knob domain in the adenovirus fiber protein is unusually high (9.0-9.1) in type 8, 19a, and 37. The pKa of sialic acid is low, 2.6, implying a possible involvement of charge in fiber knob-sialic acid interactions. Here we show that (i) positively charged adenovirus knobs require sialic acid for efficient cell membrane interactions; (ii) viral and knob interactions with immobilized sialic acid or cell-surface sialic acid are sensitive to increased ionic strength; (iii) negatively charged molecules such as sulfated glycosaminoglycans inhibit the binding of virions to target cells in a nonspecific, charge-dependent manner; and that (iv) the ability of adenovirus knobs to interact with sialic acid correlates with the overall charge on the top surface of the respective knobs as predicted by homology modeling. Taken together, the results presented provide strong evidence for a charge mechanism during the interaction between the Ad37 fiber knob and sialic acid.     

Work organization and patient care staff injuries: the impact of different care models for "alternate level of care" patients

BACKGROUND: The number of elderly patients who do not have acute-care needs has increased in many North American hospitals. These alternate level care (ALC) patients are often cognitively impaired or physically dependent. The physical and psychosocial demands on caregivers may be growing with the increased presence of ALC patients leading to greater risk for injury among staff. METHODS: This prospective cohort study characterized several models for ALC care in four acute-care hospitals in British Columbia, Canada. A cohort of 2,854 patient care staff was identified and followed for 6 months. The association between ALC model of care and type and severity of injury was examined using multinomial and ordinal logistic regression. RESULTS: Regression models demonstrated that the workers on ALC/medical nursing units with "high" ALC patient loads and specialized geriatric assessment units had the greatest risk for injury and the greatest risk for incurring serious injury. Among staff caring for ALC patients, those on dedicated ALC units had the least risk for injury and the least risk for incurring serious injury. CONCLUSIONS: The way in which ALC care is organized in hospitals affects the risk and severity of injuries among patient care staff.