Analysis of odontoblast gene expression using a novel approach,laser capture microdissection

Studying the mechanisms of molecular interactions in developing tissues demands sensitive molecular biological in vivo and in vitro techniques. Laser capture microdissection (LCM) allows for the isolation of mRNA in histological sections even from single cells, thus enabling the identification of in vivo gene expression products in closely circumscribed tissue areas. The aims of this study were to assess the optimal fixation, processing, and staining conditions to retrieve RNA from microdissected odontoblasts. Fluorometric assays and RT-PCR analysis of alpha 1(I) collagen, dentin sialophosphoprotein (Dspp), and osteocalcin (OC) confirmed that the total RNA isolated from day 0 and day 3 captured odontoblasts was sufficient in quantity and quality. Our results indicate that individual odontoblasts obtained by LCM are morphologically intact and chemically unaltered, allowing accurate molecular and biochemical analyses.     

The Tikhoff-Linberg procedure for bone tumors of the proximal humerus: the classical “extensive” technique versus a modified “transglenoid” resection

Summary The authors report on two groups of patients (each with 12) with primary bone tumors of the humerus who underwent either a classical Tikhoff-Linberg (T-L) procedure or a modified technique by which the body of the scapula was saved. The latter procedure was an en bloc resection of the glenohumeral joint after an extra-capsular osteotomy of the neck of the scapula, followed by reconstruction with a modular prosthesis. Indications, perioperative differences, and complications of both procedures are discussed. Besides producing better aesthetic and functional results, the modified technique offered the advantages of shorter anesthesia time, less blood loss, and a better anchorage of the prosthesis. The results of this study show that the proposed modification of the T-L procedure is indicated in patients with bone tumors of the proximal humerus in which invasion of the joint capsule is present without macroscopic involvement of the glenoid.Supported in part by Special Project Oncology, National Council for Research, grant no. 87.02810.44     

Meteorologic effects on dental pain conditions

Cases of treatment because of acutely occurring states of pain were analysed in a big-city dental outpatients department. The one-year examination covered about 4,000 cases of the total number of 40,000 consultations. As for the diagnoses considered in the examination, it concerned primarily dental caries, acute apical periodontitis and pulpitis. It was to find out if here is a relation between "toothache" and airhygienic influences. This was done with reference to an examination using the same method which was performed as early as in 1982/83. Apparently, there is no immediate correlation.     

Large-field S-cone flicker test

Background: Disturbances of blue color vision and of temporal contrast sensitivity can indicate early damage in glaucoma. For the present study a quick and easy test was devised which examines both functions ai one time by testing the temporal contrast sensitivity of a blue flickering light on an intense yellow background. Methods: Large coextensive background and test fields (85°) are used, making fixation uncritical. Detailed experiments were made in two normal subjects to derive spectral sensitivity curves from flicker-fusion frequency (FFF) versus intensity functions and to obtain complete temporal contrast-sensitivity (De Lange) curves under different levels of adaptation and test lights. After selection of appropriate luminances and one stimulation frequency from these experiments, test-retest variability was studied in four subjects in five repetitions. In addition, normal values were collected from 22 subjects. Results: Spectral sensitivities for two levels of FFF (15 Hz and 44 Hz) agree with Stiles' ₁ at the low and with ₄ at the high FFF. Temporal contrast-sensitivity curves show a low-frequency section with peak sensitivity at 1 Hz and a high-frequency section with a peak at around 4 Hz. From the basic experiments the following conditions for the clinical examination were selected: Background luminance 2600 cd/m², test luminance at 451 nm 0.8 cd/m², stimulation frequency 4 Hz. The test-retest variability showed an acceptable intraclass correlation coefficient (0.6). Conclusions: The present experiments carried out with a very large stimulus led to meaningful results which are in rather good agreement with results reported in the literature on small-field stimuli. The blue-on-yellow flicker test carried out under the conditions mentioned above is a quick and easy test which could be helpful in improving early glaucoma diagnosis.     

Hippocampal loss of the GABAA receptor α1 subunit in patients with chronic pharmacoresistant epilepsies

Alterations of gamma aminobutyric acid (GABA)-mediated neurotransmission have been implicated in the pathogenesis of epilepsies. Here we examine the distribution of the GABA_A receptor in the hippocampus of 78 surgical specimens from patients with chronic pharmacoresistant focal epilepsies. The receptor was localized immunohistochemically with the monoclonal antibody bd-24 which selectively recognizes the ₁ subunit of the GABA_A receptor. The results were compared with the receptor distribution of 28 normal hippocampal specimens obtained at autopsy. In the great majority of the surgical specimens a loss of GABA_A receptor immunoreactivity was present in CA1 (92.3%), CA4 (78.2%), the dentate granular cell layer (70.5%) and the molecular layer of the dentate gyrus (65.4%). The subiculum revealed a normal staining pattern in all but 4 cases. In no instance did we observe an increase of immunoreactivity in any region or cell population. The decrease of GABA_A receptor immunoreactivity was closely related to neuronal loss in the respective specimen and to Ammon's horn sclerosis. There was no correlation between GABA_A receptor loss and the patient's age at surgery, duration of seizures, age at onset of seizures and to the presence or absence of secondary generalized tonic clonic seizures. The data suggest that the observed loss of GABA_A receptor immunoreactivity is a secondary phenomenon rather than an event that is relevant for the pathogenesis of epileptic seizures.     

Original article: Effects of Raised Extracellular Magnesium on Platelet Reactivity

The inhibitory effects on platelet reactivity of increased extracellular magnesium were investigated. Wherever possible, experiments were performed in hirudinized whole blood. Concentration dependent inhibition of platelet aggregation and dense granule release were observed with MgSO(4). Antiaggregatory effects were identical with MgCl(2), indicating that the effects are due to the Mg(2+) ion. Antiaggregatory effects of CaCl(2), differed from those of MgCl(2), indicating that this is not a non-specific divalent cation effect. MgSO(4) also caused concentration-dependent inhibition of platelet thromboxane production. Experiments in the presence of apyrase and indomethacin showed that complex formation with ADP and inhibition of cyclo-oxygenase do not entirely account for the inhibitory effect of magnesium on platelet activation. Studies with an anti-GPIIb/IIIa antibody showed that the inhibitory effects on the release reaction and thromboxane synthesis are independent of those on aggregation. The results are consistent with magnesium modifying an intracellular signal transduction pathway common to several agonists, rather than the effects of magnesium being specific for one agonist. This study also shows that MgSO(4) inhibits agonist-induced increases in intracellular free calcium. Increasing the extracellular concentration of magnesium up to 10 mM had no effect on agonist-induced increments in intraplatelet free Mg(2+) concentration.     

The effect of accident mechanisms and initial findings on the long-term course of whiplash injury

The aim of this study was to assess the relationships between accident mechanisms as well as initial findings and the long-term course of whiplash injury. A representative sample of 117 consecutive patients referred by primary care physicians was followed-up over 12 months. Fractures or dislocations of the cervical spine, head trauma and pre-existing neurological disorders were exclusion criteria. The interval between the accident and the baseline examination was 7.4 days (SD 4.2 days). Assessment included accident features (e.g. passenger position in the car, head restraint, head position, type of collision), initial symptoms (e.g. intensity and onset of pain, symptoms of neurological dysfunction, multiple symptom score), and signs (restricted neck movement, neurological deficits). At the 1-year examination, patients were divided into an asymptomatic and a symptomatic group and were compared with respect to accident features and baseline findings. Twenty-four percent of patients were still symptomatic after 1 year. Analysing accident mechanisms separately, rotated or inclined head position was the primary feature related to symptom persistence (P=0.005). The symptomatic group scored higher at baseline on the multiple symptom rating (P=0.004) and had a higher incidence of initial headache (P=0.004) and neurological symptoms (P=0.008) together with a higher intensity of headache (P=0.0002) and neck pain (P=0.0009). The following set of initial variables predicted persistence of symptoms at 1 year (logistic regression): intensity of neck pain (P=0.001) and headache (P=0.009), rotated or inclined head position (P=0.02), unpreparedness at the time of impact (P=0.01) and car stationary when hit (P=0.01). In conclusion, accident mechanisms and initial findings suggestive of more severe injury were significantly related to long-term persistence of symptoms after whiplash injury.This study was supported by the Swiss National Science Foundation (project number: 3.883-0.88) and the Swiss Accident Insurance Company (Schweizerische Unfallversicherungsanstalt), Berne     

Urinary excretion of adenosine deaminase binding protein in neonates treated with tobramycin

The potential tubulotoxicity of tobramycin and cefotaxim were assessed in neonates by measuring the urinary level of adenosine deaminase binding protein (ABP) and urinary ₁-microglobulin and ₂-microglobulin. In a prospective study, 33 neonates who received tobramycin and cefotaxim for suspected neonatal sepsis were compared with 48 untreated newborns during the first 10 days of life. The urinary concentrations of ABP and its excretion rates, corrected for body weight and body surface area, were significantly increased from the 1st day of treatment. Urinary ₁-microglobulin and ₂-microglobulin were not elevated under tobramycin and cefotaxim during the first 2 days of treatment. We conclude that ABP may be a sensitive marker for the detection of proximal renal tubular injury during tobramycin and cefotaxim treatments of neonates. The increase in urinary ABP which occurs before an elevation of urinary ₁-microglobulin and ₂-microglobulin may reflect earlier structural than functional alterations. However, since none of the treated infants had signs of electrolyte disorders or glomerular dysfunction, the clinical relevance of ABP measurement should be reevaluated.     

The effect of hyperbaric oxygen on medial collateral ligament healing in a rat model

Hyperbaric oxygen has been shown to promote healing in bone and some soft tissues. This study was undertaken to determine its effect on ligamentous healing. Forty-eight Sprague-Dawley rats underwent a standardized surgical laceration of the right (divided) medial collateral ligament, whereas the left (undivided) medial collateral ligament was not surgically lacerated. A control group of 24 rats recovered without intervention. An experimental group consisting of the other 24 rats was exposed to hyperbaric oxygen at 2.8 atmospheres for 1.5 hours a day for 5 days after the surgery. Six rats from each group were euthanized at 2, 4, 6, and 8 weeks. The stiffness and final force to failure were recorded for the divided and undivided medial collateral ligaments. At 4 weeks, a statistically greater force was required to cause failure of the previously divided ligaments that had been exposed to hyperbaric oxygen than those that had not. The stiffness and force to cause failure of previously divided ligaments were statistically greater at 4 weeks than at 2 weeks, whether or not hyperbaric oxygen was used. No additional statistical increases in stiffness or force were observed at 6 weeks.     

Alcohol consumption and gender in the 20th century: the case of Switzerland

Given the changes of gender roles in this century it is hardly justified to assume constant proportions of alcohol consumption for males and females. The purpose of the study was to reconstruct the consumption trends of males and females in Switzerland since the beginning of the 20th century. Cirrhosis mortality and survey data were used to disaggregate by sex the per capita alcohol consumption based on liver cirrhosis mortality suggests that the evolution of alcohol consumption in Switzerland followed a parallel course for both sexes only until the 1930 s. The low consumption during World War II and the evident increase until the beginning of the '60s seem to have resulted above all from the variations in consumption of beer by men. The decrease in total alcohol consumption observed since the '70s is also most probably due only to men; there is no indication of a decreasing consumption by women. The tendency of male and female consumption patterns to become more similar should be taken into account in the prevention of alcohol misuse.