Factors influencing fluorescence spectra of free porphyrins

We recorded fluorescence excitation and emission spectra of uro- and coproporphyrin under different experimental conditions, to see how these conditions influence quantifications based on measurement of fluorescence intensity. We found that, for bands alpha and beta of the emission spectra and the main peak of the excitation spectra, fluorescence depends on pH and is minimal near pH 5 and near pH 7-7.5 for copro- and uroporphyrin, respectively. For band gamma of the emission spectra there was a constant decrease of fluorescence with increasing alkalinity of the solution. The intensity of porphyrin fluorescence also depends on ionic strength, reaching sharp maxima at 0.1 mol/L (for uroporphyrin) and 1 mol/L (for coproporphyrin). The organic mixture ethyl acetate:acetic acid (4:1 by vol), commonly used to extract porphyrins from biological samples, markedly diminishes the fluorescence of both porphyrins as compared with the same concentration of each porphyrin in aqueous acidic solvent. Furthermore, when we measured different ratios of uro:copro mixture at three distinct pHs and buffers, we found that at pH 10.5 (in carbonate buffer) the measured units of fluorescence depend only on total porphyrin concentration and not on the composition of the mixture.     

Impact of clinical history on fracture detection with radiography

The effect of knowledge of localizing symptoms and signs in the detection of fractures was studied. Forty radiographs of the extremities were examined twice by seven radiologists; the sessions were separated by 4 months. In 26 cases, a subtle fracture was present; 14 cases were normal. In half of the cases at each session, the precise location of pain, tenderness, or swelling was provided. The observer was asked to determine if the case was normal or abnormal (provide the exact location of the fracture) and to indicate the degree of confidence in the diagnosis. Responses were converted to a numeric scale for analysis. Analysis of receiver operator characteristic parameters indicates that clues regarding location of trauma facilitate detection of fractures. The improvement is based largely on an increased true-positive rate without an increased false-positive rate, regardless of the decision criteria of the radiologist (overall willingness to "overread" or "underread"). This has direct clinical applicability and reinforces the plea of radiologists for precise clinical information.     

Lymph node infarction – a rare complication associated with disseminated intra vascular coagulation in a case of dengue fever

Background  

Lymph node infarction is known to occur in association with many non-neoplastic and neoplastic conditions however its occurrence in association with DIC is not reported hitherto in the literature.     

Reconstruction of maxillary alveolar defects with mandibular symphysis grafts for dental implants: a preliminary procedural report.

Partially edentulous patients with alveolar defects contraindicating implant placement were treated with bone grafts obtained from the mandibular symphysis. Complications encountered were minor and uneventful. Evaluation 4 months after surgery revealed minimal graft resorption, thus implant placement was possible in all potential sites. Advantages of the symphysis graft include easy access, availability of greater quantities of bone over other intraoral donor sites, low morbidity, no hospitalization, minimal discomfort, no alteration in ambulation, and no cutaneous scar. Compared with other bone regenerative methods for implant placement, a superior quality of bone was found and a shorter healing period is required. Results of this preliminary clinical investigation demonstrate that chin grafts offer a viable alternative for reconstruction of alveolar defects prior to dental implant placement.     

Acute coronary syndromes

The first 150 words of the full text of this article appear below. Key points Coronary artery disease accounts for >30% ofdeaths in Western society. The diagnosis of myocardial infarctionshould be qualified by size, causation and time from occurrence. Mortalityis reduced by immediate or ‘primary’ percutaneouscoronary intervention or thrombolysis within the first 24 hof onset of ST-segment elevation myocardial infarction. Strategiesto reduce platelet activation (glycoprotein IIb/IIIa receptorantagonists, or clopidogrel) are now recommended in the treatmentof high-risk non-ST-segment myocardial infarction/unstable angina. Elevatedserum troponins may be the result of non-ischaemic myocardialdamage, especially in critical illness.