NEONATAL HYPERTHYROIDISM

Neonatal Graves disease, with frank cardiac failure and pronounced bilateral breast enlargement, is described in a premature infant female. Thyrotoxicosis, culminating rapidly in thyroid storm, was successfully treated by administration of Lugol's solution, digitalis and phenobarbital. The case is discussed in reference to the legitimacy of long-acting thyroid stimulator (LATS) as the originator of neontal thyrotoxicosis. Although LATS could not be detected, the occurrence of gastric parietal cell antibodies in both mother and child yielded presumptive evidence for thyrotoxicosis as an autoimmune disease.     

Experimental periodontal breakdown in the dog

abstract – This paper describes a method for inducing rapidly progressing and reproducible periodontal lesions around selected teeth in dogs. The experiments were performed on 10 beagles which were fed a diet favoring gross formation of plaque. Approximately 1 mm of the marginal alveolar bone around ₄P and P₄ was removed and a notch prepared in the root. A ligature of cotton floss was placed around ₄P and P₄ at the cemento-enamel junction. Radiographs and sections prepared 230 d later revealed that a progressive breakdown of the periodontal tissues had occurred. The average bone loss was 2.4 mm and the distance between the apical cells of the pocket epithelium and the notch was 854μm.     

Shear Bond Strengths of One-Bottle Adhesives to Moist Enamel

Abstract: Purpose: This study evaluated bond strengths of six one-bottle bonding agents and a control (primer plus unfilled resin) to moist enamel.
Materials and Methods: One-hundred and five bovine teeth were randomly assigned to seven groups of 15. Enamel was etched for 15 seconds with 35% phosphoric acid. Etched enamel was rinsed, and excess water was blotted with tissue paper. Following application of the adhesive, composite resin was bonded using a gelatin capsule technique. Shear bond strengths to enamel were determined using a universal testing machine (Instron Corp., Canton, Massachusetts).
Results: Mean bond strengths ranged from 21.9 MPa for OptiBond Solo (Kerr Corp., Orange, California) to 29.6 MPa for Prime & Bond 2.1 (Dentsply/Caulk, Milford, Delaware). Prime & Bond 2.1 had a significantly higher mean bond strength than the other adhesives.
CLINICAL SIGNIFICANCE: The results of this study suggest that all of the one-bottle systems tested should provide clinically acceptable bonding to moist enamel.     

Does activation of the baroreceptors reinforce differential Pavlovian conditioning of heart rate responses?

High- and low-pitched tones (CS+ and CS?) signalled baroreceptor stimulation or inhibition (US+ and US-) on 6-s conditioning trials (n= 128). Baroreceptor stimulation was induced by the phase-related external suction (PRES) method of Rau et al. (1992) in which a brief pulse of negative external pressure is applied to the neck at systole and one of positive pressure at diastole within each cardiac cycle (the reverse sequence is used for baroreceptor inhibition). Changes in heart period (R-R intervals) confirmed that PRES manipulated the baroreceptors in the presence of CS+ and CS? without habituation over conditioning trials. However, conditioned heart period responses were not observed on test trials (n= 32) in which CS+ and CS? were presented with the baroreceptor manipulation removed. Subjects were unable to state which CS had signalled baroreceptor stimulation and inhibition when given PRES-alone trials after the conditioning phase (differential attention thus controlled). These results (a) confirm that the differential effect of the two PRES stimuli was specific to the baroreceptors and (b) support earlier studies that have found that differential conditioning is impaired when CS?US relations are not processed in attention. We discuss implications regarding when baroreceptor firing might be discriminable and reinforcing.     

Coronary heart disease and upper airway obstruction

SUMMARY  Coronary heart disease (CHD) is a leading cause of death among middle-aged men. In the same age group the spectrum of upper airway obstruction from habitual snoring to obstructive sleep apnoea syndrome (OSAS) is frequent. In several studies snoring was found to be an important risk factor for ischaemic heart disease. The prevalence of OSAS in patients with CHD, profile of risk factors and ventricular arrhythmias was determined in a prospective manner in 78 patients with stenosis of one or more coronary arteries at coronary arterography. OSAS was found in 27 patients (34.6%). Mean respiratory disturbance index (RDI) was 23.9. RDI increased with higher age. No significant differences in both groups could be found in ventricular arrhythmias, left ventricular ejection fraction and risk factors, except hyperuricaemia and adiposity. OSAS is frequent in patients with CHD and may be an additional risk factor besides the known coronary risk factors. Patients with the combination of CHD and OSAS have to be regarded as a group at particular risk because of several interactions between OSAS and coronary haemodynamics. Furthermore the microstructure of sleep in patients with nocturnal myocardial ischaemia is disturbed.     

The influence of sympathetic nerve activity on axial position of the rabbit incisor tooth

Changes in position of the upper front tooth in response to sectioning and subsequent electrical stimulation of the cervical sympathetic nerves were studied in 25 anesthetized rabbits. The position was continuously recorded by an ultrasonic transit time technique. Sectioning of the nerves was found to induce an average tooth extrusion of about 7 μm. Sympathetic nerve stimulation for periods of 20–30 s caused intrusion of the tooth, with about 70% of maximum occurring at 2 Hz stimulations. The intrusive response was reduced by phentolamine. Neither atropine nor propranolol affected the stimulation response, but the latter drug led to marked extrusion of the tooth. In conclusion, the position of the rabbit's front tooth was found to be highly sensitive to alterations in sympathetic nerve activity to the vasculature of the tooth-supporting tissues.     

Stenting of Native Right Ventricular Outflow Tract Obstructions in Symptomatic Infants

Objective

To assess feasibility, safety and effectiveness of right ventricular outflow tract (RVOT) stenting in symptomatic young infants.

Methods

Multicentre evaluation of 35 patients intended to undergo RVOT stenting in 11 pediatric cardiac centres from 2009 to August 2011.

Results

Median age and weight at the time of first stent implantation were 8 weeks and 3.3 kg, with 40% of patients <3 kg. A total of 19 patients had suffered from hypoxemic spells, 8 patients were ventilated, 6 on inotropic support and 5 on prostaglandin infusion. Severe concomitant malformations were present in 11 patients, and acute infections in 2. Stenting of the RVOT was successfully performed in 33 patients, improving oxygen saturation from a median of 77 to 90% 2 days after intervention. Besides the 2 patients in whom RVOT stenting was not successful for technical reasons, there were no procedural complications. In 17 of 33 patients, 1–3 reinterventions were performed during follow‐up, less than half of those were reinterventions in the RVOT. A total of 27 patients have undergone successful surgical repair 4–162 (median 19.5) weeks after initial RVOT stent implantation, 2 patients are still waiting. There were no perioperative deaths.

Conclusions

Stenting of the RVOT provides a safe and effective management strategy for initial palliation in symptomatic young infants, including those patients not suitable or at higher risk for surgical therapy. (J Interven Cardiol 2015;28:279–287)

     

Glomerular filtraton rate and PCO2 as determinants of lithium reabsorption

To examine whether lithium reabsorption varies in proportion to the bicarbonate-dependent reabsorption of water and chloride, reabsorption was altered by varying P_CO2 and glomerular filtration rate (GFR) in volume-expanded, anesthetized dogs during ethacrynic acid infusion. At constant GFR and plasma bicarbonate concentration, lithium, bicarbonate, chloride and water reabsorption were inversely related to plasma pH during variations in PCO2. Lithium and bicarbonate reabsorption varied by 9±1% and chloride reabsorption by 7±1% as plasma pH was altered by 0.1 unit from plasma pH 7.5. Calculation of reabsorbate concentrations indicated that lithium was reabsorbed as readily as water (reflection coefficient=0). During mechanical constriction of the suprarenal aorta, GFR was reduced at constant plasma pH. Bicarbonate reabsorption fell more than chloride, water and lithium reabsorption. Lithium reabsorption was not significantly reduced until GFR was reduced by 35%. In stop-flow studies during ouabain infusion, urinary lithium concentrations were reduced below plasma concentrations. This is compatible with passive diffusion of lithium along a lumen-positive potential exceeding 10 mV in the diluting segment. Thus, lithium reabsorption behaved as expected for bicarbonate-dependent paracellular reabsorption during variations in P_CO2; when GFR is reduced, an additional component of lithium reabsorption is disclosed.     

Examination of Left External and Internal Carotid Arteries During Transesophageal Echocardiography

The present study demonstrates the feasibility of delineating the carotid bulb and the proximal portions of the left external and left internal carotid arteries during transesophageal examination. This was accomplished by slowly and carefully withdrawing the probe from the esophagus into the pharynx.