Inhibition of bacterial growth by tetracycline-impregnated enamel and dentin

Tetracyclines can react with enamel and dentin to form relatively insoluble fluorescent compounds. The purpose of this study was to evaluate the possible antimicrobial effect of these reaction products on various microorganisms associated with human dental plaque and periodontal disease. Slabs of native dentin and enamel as well as demineralized dentin were immersed in aqueous solutions of tetracycline HC1, oxytetracycline HC1 and doxycycline HC1 for periods of 1 h or 24 h. Unimpregnated enamel and dentin slabs sterilized by gamma irradiation and specimens impregnated with phenoxymethylpenicillin calcium were used as controls. Test and control specimens were placed on agar plates seeded with B. cereus, C. ochraceus, S. sanguis, F. nucleatum, B. melaninogenicus or A. viscosus and were subsequently incubated aerobically or anaerobically at 37°C. With the exception of enamel impregnated for 1 h in a 0.01 mg/ml tetracycline solution, all test specimens caused growth inhibition zones, varying in size according to concentration of the drug, immersion period and bacterial species. The results indicate that tetracyclines react with enamel and dentin to form slightly soluble compounds with a pronounced antibacterial effect. In comparison, the antimicrobial effect of dentin treated with penicillin was small.     

Is Smoking Intervention in General Practice More Successful Among Pregnant Than Non-pregnant Women?

The objective of this study was to evaluate the effect of asimple smoking intervention programme, carried out by a largenumber of general practitioners (GPs) among pregnant and non-pregnantwomen. Four groups of women were defined by the dichotomiespregnant versus non-pregnant and intervention versus control.The intervention was semistructured, using a flip-over and abooklet, and it was implemented in an ordinary sequence of consultations.The study involved 187 GPs in western Norway. The subjects were350 daily smoking pregnant women and 274 daily smoking non-pregnantwomen, 18–34 years of age. The point prevalence abstinencerate at 18 months was 15 and 20% for pregnant and non-pregnantwomen, respectively, in the intervention groups, and 7% in thecontrol groups (P_pregnant = 0.06, P_non-pregnant = 0.006) Twenty-fiveper cent of the pregnant women and 34% of the non-pregnant womenreported that they had reduced their cigarette consumption,but had not stopped smoking entirely. If we include all drop-outsas smokers, the continuous abstinence rate during 15 monthswas 6%/0% among pregnant women (intervention/control) and 5%/1%among non-pregnant women. Stopping smoking was associated withhaving a non-smoking partnér {P = 0.001), and being encouragedto do so by their partner (P = 0.004). The prevalence of bothpregnant and non-pregnant women who stopped smoking was higherin the intervention than in the control groups. Pregnant womenstopped smoking as frequently as non-pregnant individuals. However,concerning mean daily cigarette consumption, a positive effectof the intervention was only observed for the non-pregnant women.There is a potential for more women to become non-smokers duringthe periods of pregnancy and child infancy. GPs should receivemore training in this specific health promotion effort. Moreeffective, low cost smoking intervention programmes, designedfor pregnant women should be explored.     

Dental findings in patients with Aarskog syndrome

Abstract— Dental manifestations of the Aarskog syndrome were studied in 10 individuals. There was retarded development and eruption of the permanent teeth in six boys. Dental age was less retarded than height age and bone age. The prevalence of hypodontia and the prevalence and degree of orthodontic anomalies were higher than in the general population. Caries prevalence was high.     

Gangliosides increase the survival of lesioned nigral dopamine neurons and favour the recovery of dopaminergic synaptic function in striatum of rats by collateral sprouting*

The effects of chronic ganglioside treatment GM-1 (10 mg/kg, i. p., once daily for 56 days) have been evaluated on the degenerative and regenerative features of nigrostriatal dopamine (DA) neurons following a partial lesion by tyrosine hydroxylase immunocytochemistry in combination with morphometrical analysis and by quantitative DA receptor autoradiography. Chronic GM-1 treatment resulted in the maintenance in the number of DA cell bodies, terminals and striatal area on the lesioned side and also increased dendrite length of the DA nerve cells in the zona reticulata on that side. The lesion induced DA receptor supersensitivity was counteracted by chronic treatment with GM-1 and the apomorphine induced rotational behaviour was significantly reduced. The hypothesis is introduced that following ganglioside treatment some lesioned DA nerve cells do not degenerate, but elongate their dendrites to give increased trophic support to DA cell bodies with intact DA axons. These increased dendro-dendritic interactions may enable the unlesioned DA cells to increase the density of their striatal nerve terminal networks via collateral sprouting leading to recovery of dopaminergic synaptic function as evidenced in the receptor autoradiographical and behavioural analysis. Gangliosides may therefore possibly represent a new type of drug in the treatment of Parkinson's disease and aging processes in DA systems.     

Chronic treatment with I-dopa plus carbidopa in hemitransected rats: Preferential effects at intact dopamine synapses leading to behavioural signs of dopamine receptor supersensitivity

Chronic i. p. treatment with 1-dopa-carbidopa for 3 weeks in hemitransected male rats leads on one hand to tolerance to l-dopa induced turning behaviour and on the other hand to behavioural and biochemical signs of dopamine (DA) receptor supersensitivity on the intact side. Thus, the apomorphine induced ipsilateral turning behaviour is enhanced and the K_d values of the ³H-spiperone binding sites linked to DA receptors of the D₂ type on the intact, but not on the denervated side are reduced by 40%. However, the number of ³H-spiperone binding sites is reduced by 20% in striatal membranes on the intact side after this type of treatment. Therefore, chronic treatment with a catecholamine (CA) precursor leads to selective adaptive changes at intact striatal DA synapses with certain signs of the expected development of DA receptor subsensitivity, but above all with signs of paradoxical development of DA receptor supersensitivity. A hypothesis is introduced to explain these results.     

Intracisternal administration of avian pancreatic polypeptide lowers respiration rate and enhances the clonidine induced reduction of respiration rate in α-chloralose anesthetized rats: Possible interactions with an α2-adrenergic receptor

Avian pancreatic polypeptide (APP) is a 36 amino acid peptide isolated from chicken pancreas (Kim-mel et al. 1975) and there exists a wide-spread distribution of APP-like immunoreactive nerve cell bodies and terminals in the central and peripheral nervous systems (Lorén et al. 1979, Hökfelt et al. 1981). Furthermore, it has recently been discovered (Lundberg et al. 1980a) that an APP-like immunoreactive substance (Kimmel et al. 1975) is present in central phenylethanolamine-N-methyltransferase (PNMT) immunoreactive neurons and in some noradrenaline (NA) neurons. Thus, an APP-like peptide and adrenaline (A) may coexist in some A nerve cells in the central nervous system (see also Hunt et al. 1981). This coexistence appears to exist in A nerve cells of both cell groups C1 and C2 (Hökfelt et al. 1974, Lundberg et al. 1980a). Evidence exists that many of the A neuron systems of the brain represent vasodepressor pathways, and it has been suggested that clonidine may produce at least part of its hypotensive actions via activation of postsynaptic α₂-adrenergic receptors linked to A synapses in the brain, especially in the medulla oblongata (Bolme et al. 1974, Fuxe et al. 1975, Fuxe et al. 1980). It has also been suggested that certain A neurons regulate respiration rate and the clonidine induced reduction of respiration rate may therefore at least in part be mediated via α₂-adrenergic receptors linked to A synapses in the medulla oblongata (Bolme et al. 1974). In order to understand the possible functional significance of co-storage of APP-like material and A we have now investigated the effects of APP and for comparison also bovine pancreatic polypeptide (BPP) (Chance & Jones 1974), which differ in only one or two positions from other mammalian forms of the peptide, on cardiovascular parameters and on respiration rate and on clonidine induced reduction of arterial blood pressure and respiration rate. BPP differs in 21 positions from APP, but BPP-like and APP-like immunoreactive neurons are distributed in the rat brain in a similar way and seem to represent one and the same neuronal system (Ol-schowska et al. 1981). Thus, APP/BPP-like immunoreactive material exists in the A neurons, but its exact identity is unknown.     

Serum protein pattern in normal pregnancy with special reference to acute-phase reactants

Summary. The concentrations of acute-phase protein reactants, total protein, albumin and globulin fractions were measured throughout normal pregnancy in 27 women. α₁-Antitrypsin and caeruloplasmin concentrations increased gradually to reach their highest levels in the third trimester. Orosomucoid and haptoglobin showed similar patterns: higher levels in the first and third trimester with a decline around 24 weeks gestation. C-Reactive protein showed levels similar to those of non-pregnant healthy individuals (< 5 mg/1) throughout pregnancy. α₁,-, α₂ and β-Globulin concentrations increased from the first trimester towards term. γ-Globulin concentration changed little during gestation. The data obtained provide reference ranges for serum proteins in healthy pregnancy.     

Clinical Performance of Steroid-Eluting Pacing Leads with 1.2-mm2 Electrodes

To raise pacing impedance and reduce battery current drain, new tined steroid-eluting leads were developed with 1.2-mm² hemispherical electrodes, instead of conventional 5–8 mm². Twenty-two unipolar J-shaped atrial leads and 25 unipolar ventricular leads (models 4533 and 4033, respectively) were implanted in 33 consecutive patients and followed for a mean of 25 months (range 18–29). Handling characteristics of atrial leads were found favorable. The leads slipped easily into the right atrial appendage and were easy to position. Handling characteristics of ventricular leads were satisfying, but more efforts had to be applied to cross the tricuspid valve. Special care was taken to avoid perforation of the myocardium due to the small lead tip. Following implantation, four ventricular and one atrial lead exhibited instability of pacing thresholds that resolved spontaneously within 1–3 days of implantation. Except for this, no lead malfunctioned. The reoperation rate was zero. The mean electrogram amplitudes of 15 mV (ventricle) and 4 mV (atrium), and the mean chronic pacing threshold of 0.085 ms at 1.6 V (app. 0.43 Vat 0.5 ms) were comparable with the best values seen in the literature on passive fixation leads. The rest of the electrophysiological parameters were enhanced: mean pacing impedances were 984 Ω (acute) and 900 Ω (chronic), mean slew rates 3.26 V/s (ventricle) and 1.75 V/s (atrium), mean acute voltage threshold at 0.5 ms was 0.25 V, mean current and energy thresholds calculated at 0.5 ms were 260 μA and 32 nJ (acute) and 478 μA and 103 nJ (chronic). The electrical characteristics of these leads provide for increased pacemaker longevity in combination with substantial safety margins for pacing and sensing.