Dental fluorosis among participants in a non-supervised fluoride tablet program

The aim of the present study was to describe the intraoral pattern of dental fluorosis among fluoride tablet consumers. One hundred and forty-two children, of whom 56 had participated in a fluoride tablet program of 0.5/1.0 mg NaF per day were examined blindly for possible fluoride-induced enamel changes. A low prevalence of dental fluorosis was found among non-participants. The later in life the tooth was formed, the higher was the prevalence. The subjects who had participated in the fluoride tablet program showed a significantly higher prevalence of fluorosis. They could be divided into three groups: Group 1 exhibited a tooth prevalence pattern not statistically different from that of the non-participants, group 2 showed dental fluorosis in almost all teeth except in those formed before the start of the tablet program. In group 3 the early and the late formed teeth showed very little fluorosis while those formed in the few years just after the initiation of the fluoride tablet intake were affected by fluorosis.     

Ketamine and midazolam decrease cerebral blood flow and consequently their own rate of transport to the brain: An application of mass balance pharmacokinetics with a changing regional blood flow

Mass balance pharmacokinetics, with simultaneous blood sampling from an artery and the internal jugular vein, was used to characterize the cerebral uptake of ketamine, norketamine, and midazolam in normoventilated pigs. Intravenous injections of ketamine or midazolam decreased the cerebral blood flow (CBF)by one third, as measured by intermittent ¹³³Xewashout. By means of pharmacodynamic models, the effects on the CBFcould be predicted from the arterial drug concentrations. The high-resolution CBFvs. time curves thus generated allowed the calculation of cerebral drug levels from arteriovenous concentration gradients in spite of a continuously changing regional blood flow. By their effects on the CBF,ketamine and midazolam decreasetheir own rateof transport to the brain, the immediate 30-35% drops in CBFgiving similar reductions in initial net influx of drug. Physiological pharmacokinetic models assuming a constant regional blood flow are therefore not appropriate. Under clinical conditions, the CBFis determined mainly by the effects of the anesthetics and by the arterial CO ₂ tension. CBFchanges in either direction influence the transport of drugs to the brain and may consequently result in impaired or exaggerated drug effects.The study was supported by grants from the Swedish Medical Research Council (B91-14X-00084-27A), the Medical Faculty at Lund University, Malmö General Hospital, The Tore Nilsson Foundation for Medical Research, Warner-Lambert Scandinavia AB, Roche-Produkter AB, and the Laerdal Foundation for Acute Medicine.     

The accessory optic system in the frog, Rana pipiens: An electron microscopic study of the retinal afferents utilizing the anterograde tracer biocytin

The retinal afferents to the basal optic nucleus in the frog, Rana Pipiens, were labeled anterogradely with biocytin and subsequently studied at the electron microscopic level. Labeled synaptic terminals in the nucleus varied in size from 0.5 μm to 2.0 μm and made symmetric synaptic contacts with large and small dendrites, although very rare axospinous and axosomatic contacts were also demonstrated.     

Antagonism of Reserpine-Induced Suppression of Spontaneous Motor Activity by Stimulation of 5-HT1A Receptors in Rats

Abstract: The 5-HT_1A and the DA D₂ receptor agonists 8-OH-DPAT (0.05–3.2 mg kg^–1 subcutaneously, –20 min.) and quinpirole (0.08–1.25 mg kg^–1 subcutaneously, –20 min.), respectively, both partially antagonized reserpine-induced (5 mg kg^–1 subcutaneously, –16 hr) suppression of spontaneous motor activity in the rat. Four different aspects of the spontaneous motor activity were recorded in a photocell-equipped open-field (8x8 photocells, 90 mm apart, defining two horizontal planes): locomotor activity (all photocell counts at the lower level); rearing (all photocell counts at the upper level); forward locomotion (the proportion movements across the arena); peripheral activity (the proportion locomotor activity as picked up by the photocell beam closest to the wall, i.e. 25 mm). As denned by these variables, the pattern of activity produced by 8-OH-DPAT or quinpirole were indistinguishable, The effects produced by 8-OH-DPAT were fully antagonized by the 5-HT₁ antagonist (–) pindolol (4 mg kg^–1 subcutaneously, –30 min.), but not by the DA D₂ receptor antagonist raclopride (2 mg kg^–1 subcutaneously, –30 min.) nor by the 5-HT₂ receptor antagonist ritanserin (2 mg kg^–1 subcutaneously, –30 min.), whereas effects produced by quinpirole were fully antagonized by raclopride (2 mg kg^–1 subcutaneously, –30 min.). Effects produced by quinpirole, but not 8-OH-DPAT, were potentiated by administration of the DA D₁ agonist SKF-38,393 (3 mg kg^–1 subcutaneously, –20 min.). It is concluded that effects by 8-OH-DPAT on spontaneous motor activity in the reserpine treated rat primarily are due to stimulation of postsynaptic 5-HT_1A receptors.     

A case of high mercury exposure from dental amalgam

This report describes a patient who suffered from several complaints, which by herself were attributed to her amalgam fillings. Analysis of mercury in plasma and urine showed unexpectedly high concentrations. 63 and 223 nmol/l. respectively. Following removal of the amalgam fillings, the urinary excretion of mercury became gradually normalized, and her symptoms declined.     

The Effect of Chronic Lithium Treatment on the Sialic Acid Content in Rat Brain Synaptosomes

Abstract: Rats were fed a lithium-containing diet for five weeks (40 mmol LiCl/kg fodder). Plasma lithium concentration was 0.44 mmol Li⁺/1 plasma. The synaptosomes were isolated and incubated with ³H-glucosamine for 60 min. The glycopeptides and the gangliosides were extracted and the sialic acid content and the ³H-sialic acid content were measured. The lithium treatment produced an increase in the synaptosomal glycopeptide content. The sialic acid content was simultaneously increased in glycopeptides as well as gangliosides. The specific activity of sialic acid was reduced to 75% of the control value in the sialoglycopeptide fraction.     

Role of serotonin in memory: facilitation by alaproclate and zimeldine

The effects of alaproclate and zimeldine on memory retrieval were examined in male Swiss Webster mice using a one-trial inhibitory avoidance task. All drugs were administered IP prior to the retention test 24 h after training. Both drugs were found to facilitate memory retrieval significantly in a dose-and time-dependent fashion that could not be explained in terms of non-specific effects of the drug (illness, lack of motility, etc.) at the time of the test. The temporal effects of alaproclate and zimeldine on memory closely followed their course of concentration of the drug within the blood stream. The facilitation of retrieval induced by alaproclate and zimeldine was blocked by the putative serotonergic receptor agonist quipazine but not blocked by the antagonist cyproheptadine. Pretreatment with quipazine alone in a group of animals trained to a shock level which normally results in high levels of suppression was not sufficient to produce memory impairment, suggesting that quipazine was probably antagonizing the facilitative effects of alaproclate and zimeldine directly, rather than overriding the facilitation through an indirect action on retrieval in general. The present results lend further support to the suggestion that serotonin plays a significant role in memory.     

Interferon Production,Cellular and Humoral Immunity in Splenectomized Patients

Undetectable levels of circulating interferon were found in 35 splenectomized patients and in 14 controls. In addition, no differences in virus, purified protein derivative (PPD), and phytohaemagglutinin (PHA) induced interferon production were observed between the patients and the controls. Virus induced lymphocyte transformation tended to be reduced after splenectomy, but only the herpes simplex virus (HSV) induced transformation index was significantly reduced in splenectomized patients without residual splenic tissue (P < 0.05). In contrast, the PHA lymphocyte transformation was unchanged in patients and controls. The number of natural viral antibodies in splenectomized patients did not differ from that of controls. Furthermore, there were no major differences in the magnitude of the titers of the sero-positive cases between the various groups. Thus, splenectomy does not interfere with interferon production in vitro, and as seen from natural viral antibodies, no impairment of humoral immunity was observed. The reduced HSV lymphocyte transformation may indicate an impaired lymphocyte function after splenectomy.     

Recent life changes and coronary heart disease in East versus West Finland

Coronary heart disease (CHD) is not equally prevalent in East vs West Finland. Substantially higher CHD rates are found in East Finland, and these higher rates are only partially explained by differences in physiological “risk factors” such as body mass, blood pressure, cigarette smoking, and serum cholesterol levels between persons in these two regions. Recent life changes magnitudes were assessed for representative groups of men living in these two areas of Finland. East Finns reported approximately 84% higher life change magnitude than West Finns. Subjects' life changes magnitudes were essentially unrelated to their physiological risk factors. The relatively increased life change levels seen for East Finns may constitute an environmental risk factor for CHD.     

Effects of amount of contact between mother and child on the mother's nursing behavior

Short-term effects of different amounts of body contact between mother and newborn on human nursing behavior were studied. Extended contact immediately after parturition was related to an increase in affective components of maternal nursing behavior observed on postpartum Days 2 and 4.