Pre- and afterload reduction in chronic mitral regurgitation: a double-blind randomized placebo-controlled trial of the acute and 2 weeks' effect of nifedipine or isosorbide dinitrate treatment on left ventricular function and the severity of mitral regurgitation

1 The acute effect and effect of 14 days' treatment with isosorbide dinitrate (ISDN) and nifedipine (NIF) was evaluated by radionuclide cardiography in patients with chronic mitral regurgitation and sinus rhythm.
2 In 23 patients with clinically stable disease blood pressure was lowered by 15% and left ventricular volume was reduced by 16–20% after 20  mg sublingual ISDN causing combined pre-and afterload reduction. Afterload reduction alone induced by 10  mg NIF resulted in an acute 9% decrease in left ventricular endsystolic volume, whereas forward stroke volume increased by 30%, and regurgitation fraction tended to decrease. No haemodynamic effects could be detected after 14 days' treatment with 20  mg ISDN orally twice daily (preload reduction), whereas 20  mg NIF twice daily (afterload reduction) caused an increase in forward stroke volume (18%) and a decrease in both regurgitant volume (20%) and regurgitation fraction (22%) without affecting blood pressure or heart rate.
3 ISDN and NIF have beneficial acute haemodynamic effects in patients with chronic mitral regurgitation probably due to their pre- and afterload reducing properties. The reduction in regurgitation induced by NIF appears to be sustained after 14 days therapy.     

Impact of Age and Basic Heart Rate on Heart Rate Turbulence in Healthy Persons

Postextrasystolic acceleration of heart rate (HR), known as HR turbulence (HRT) is attenuated in patients with coronary artery disease at increased risk of adverse events. The influence of age and basic HR on HRT have not been evaluated in a large cohort of persons. In 95 healthy individuals, HRT onset (TO) and slope (TS) were calculated from 24-hour ambulatory electrocardiograms, as well as the turbulence timing (TT). Gender specific differences in TO and TS were compared in simple, linear, weighted regression model. The influence of age and the basic HR preceding ventricular premature contractions on HRT were examined. We found that, in men and women, TO decreases as basic HR increases (P < 0.01). In contrast, in men, TS decreased as basic HR increases, whereas in women, basic HR influenced TS only slightly (P < 0.01). A multiple, linear regression model revealed a decrease in HRT with increasing age in men. In conclusion, physiological acceleration of the HR within the first 11 beats after premature ventricular complex (VPC) was observed in >75% of healthy individuals. An accelerating HR preceding the VPC influenced HRT in men. An increasing age was associated with a decrease in HRT in men and a decrease in TO in women. These results illustrate the importance of physiological modulations of HRT when used for risk stratification, especially in older populations.     

The recovery of the capacity for uptake-retention of ( 3 H)noradrenaline in rat adrenergic nerves after reserpine

The uptake retention of [³H]noradrenaline (2.5 μg/kg, i.v., 30 min before death) in rat salivary glands was studied at different times after reserpine treatment (10 mg/kg, i.p.). The effect of removing the cervical superior ganglion 12 h before death on the recovery of the [³H]noradrenaline uptake-retention capacity after reserpine was also investigated. The ganglionectomy was unilateral, and the contralateral side was always preganglionically denervated. In glands with uninterrupted postganglionic adrenergic nerves the onset of recovery of the [³H]noradrenaline retention capacity occurred 24–36 h after reserpine. Normal contents were found on the second to third days. Between day 3 and 6 a possible overshoot of [³H]nor- adrenaline content, followed by normal and subnormal contents (7–21 days) were recorded. Ganglionectomy, 12 h before death, markedly delayed the recovery of [³H]noradrenaline retention capacity. Both the recovery curve for [³H]noradrenaline retention in glands with intact postganglionic nerves, and the effect of ganglionectomy on the [³H]noradrenaline retention capacity, were clearly related to the relative number of new functioning amine granules that are transported via the axons to the nerve terminals at different times after the reserpine-pretreatment. The results indicate that young amine granules, recently transported to the nerve terminals via the axons, have the greatest capacity to take up and retain [³H]noradrenaline. The half-life of this capacity in the young granules appears to be about 12 h. Since published results indicate that [³H]noradrenaline is initially taken up in the “small easily releasable pool” of transmitter, we suggest that young amine granules are of the greatest importance for adrenergic function, i.e. that they are particularly active in taking up recaptured noradrenaline, in the synthesis, and in the release of this transmitter.     

Classification of β-adrenoceptors in the microcirculation of skeletal muscle

Nervous and humoral β-adrenergic, postjunctional effects on microvascular resistance, on precapillary sphincter tone, and on transcapillary fluid exchange in cat skeletal muscle (Lundvall & Järhult 1974, 1976 a, Lundvall & Hillman 1978 a, b) were evaluated with regard to the β₁-or β₂,-specificity of the adrenoceptors. Marked β₂-dilator responses but no significant β₁-effects were observed. The conclusion was therefore reached that neurogenic as well as humoral β-adrenergic control of the microcirculation in skeletal muscle is exerted via activation of β₂-adrenoceptors.     

Pain and fear in connection to orthodontic extractions of deciduous canines

International Journal of Paediatric Dentistry 2010; 20: 193–200 Background. Interceptive extractions of deciduous canines are, from a patient perspective, poorly investigated. Aims. To describe pain, discomfort, and dental fear in connection to extractions of the deciduous canines, indicated as an orthodontic treatment procedure. Design. Thirty‐two Swedish children aged 7–9 years had all four deciduous canines extracted over three occasions. The children rated procedural and postoperative pain on visual analogue scales. Acceptance of injections and extractions was assessed by the treating dentists. Analgesic consumption and recovery time for drinking and eating was reported by parents. Dental fear was assessed using the Children’s Fear Survey Schedule questionnaire. Results. Procedural pain showed low median levels, although some individuals reported high values. Boys reported significantly more pain at appointments when two (as opposed to one) canines were extracted. Postoperative pain levels were low and use of analgesics sparse. Dental fear paralleled norm values and did not increase from pre‐ to post‐extraction. Conclusions. Pain management routines during extractions of this kind should be revised. Single tooth extractions seem to be preferable to extractions of two canines at the same appointment. Extraction of four deciduous canines should not cause major postoperative inconvenience; these extractions neither triggered nor increased dental fear.     

Is there a positive relationship between molar incisor hypomineralisations and the presence of dental caries?

International Journal of Paediatric Dentistry 2013; 23: 116–124 Objective This epidemiological study aimed to compare the caries experience in 10‐year‐olds with and without molar incisor hypomineralisation (MIH). Methods About 693 children from an ongoing birth cohort study (GINIplus10) were examined for caries lesions to determine the DMF index. Furthermore, enamel hypomineralisation (EH) was scored on all permanent teeth/surfaces, according to the criteria of the European Academy of Paediatric Dentistry. Children with EH were categorised into those with a minimum of one EH in the permanent dentition (MIH/1), with EH on at least one‐first permanent molar (MIH/1A), on at least one‐first permanent molar and permanent incisor (MIH/1B), and on other permanent teeth (MIH/1C). Results The mean caries experience was 0.4 (SD 0.9) DMFT. Existence of MIH/1, MIH/1A, MIH/1B, and MIH/1C was determined in 36.5%, 14.7%, 9.4%, and 21.8% of all children. The corresponding DMFT values were the following: no MIH: 0.3 (SD 0.8); MIH/1: 0.5 (SD 0.9); MIH/1A: 0.5 (SD 0.9); MIH/1B: 0.4 (SD 0.9); and MIH/1C: 0.4 (SD 0.9) DMFT. No significant differences were found between all groups. Conclusions There was no relationship between the presence of EH/MIH and caries in 10‐year‐olds. A ratio of one EH‐associated defect to two caries lesions indicates that both conditions are prevalent and influence the oral health status of 10‐year‐old children from Munich, Germany.     

In vitro lymphocyte reactivity to gold compounds in the diagnosis of contact hypersensitivity

The use of the lymphocyte transformation test (LTT) in the diagnosis of contact hypersensitivity to gold was studied in 8 patients who had positive patch tests to gold salts, and in 8 control subjects who were negative to such patch tests. Gold sodium thiosulfate and gold chloride were added to cultures of lymphocytes, which were labeled by 3H-thymidine after 96 h. The lymphocyte stimulation index was calculated as the beta-counts in stimulated cultures divided by those in control cultures. The index was statistically significantly higher for the patient group (p=0.005-0.04) than for the control group. Levels of interferon-gamma (IFN-gamma) were determined for the supernatants of the lymphocyte cultures. An index IFN-gamma, which is defined as the level of IFN-gamma in stimulated cultures divided by that in control cultures, was statistically significantly higher for the patient group (p=0.01-0.006). The LTT stimulation index showed specificity and sensitivity between 67 and 80%, the respective values for Index IFN-gamma being between 73 and 100% when the patch test was used as a reference method. Evaluation of lymphocyte reactivity might be of future interest in the diagnosis of allergic reactions to gold if the sensitivity and specificity can be improved.