Variation in phosphoric acid concentration and treatment time and HEMA diffusion through dentin

IGF-1 and its receptors have been identified in many tissues including the central nervous system (CNS). We have previously demonstrated that injection of insulin directly into the cerebral ventricles (ICV) is followed by a drop in mean arterial pressure (MAP) associated with an increase in skeletal muscle blood flow. Given the similarities between the IGF-1 and insulin molecules and their respective receptors, we have investigated the effect of ICV administration of IGF-1 on systemic blood pressure and blood flow in selected vascular beds. ICV cannulas were implanted into normal rats and the animals were allowed to recover for 3 to 4 days. The femoral artery and vein were cannulated for blood pressure monitoring and blood sampling and blood flow probes placed around the iliac, the renal and the superior mesenteric artery were used to assess regional blood flow. ICV injection of IGF-1 resulted in a significant decrease in MAP with a nadir at 15 minutes and a gradual return to baseline by 60 minutes; heart rate increased 40 minutes after the injection. IGF-1 significantly enhanced vascular flow and conductance in the iliac, but not in the renal and superior mesenteric arteries. The effects of IGF-1 were much smaller than those observed previously with equimolar amounts of insulin. We conclude that IGF-1 can decrease MAP by selectively increasing blood flow to skeletal muscle through a direct action on the central nervous system.     

Differential therapy of cerebral arteriovenous malformations. An analysis with reference to personal microsurgery experiences

A total of 126 patients (63 female, 63 male) underwent microsurgical removal of their cerebral arteriovenous malformations (AVMs) by the same surgeon. The mean age at surgery was 34.7 (6-72) years. The symptoms were intracerebral hemorrhage (37.3%), seizure disorder (34.9%) or focal neurological deficits and minor symptoms. According to the Spetzler/Martin scale, 20.6% of the AVMs were grade I, 28.6% grade II, 32.5% grade III, 14.3% grade IV and 4% grade V. In all, 78 AVMs (61.9%) were located in functionally important brain regions. The series was split into three different groups: small AVMs under 3 cm in diameter (n = 62/49.2%), medium-sized AVMs (n = 58/46%) and large AVMs (n = 6/4.8%). Seventeen patients had preoperative embolization of their AVM. All patients had postoperative angiographic control and 3- and 6-month follow-up. One patient died (0.8%), and another one (0.8%), in whom the AVM was incompletely resected, suffered a secondary hemorrhage. Seventeen (27.4%) of the patients with small AVMs developed transient neurological worsening post-operatively, which remained permanently significant in 3.2%. The respective numbers for the patients with medium-sized AVMs were 48.3% and 10.3% and for the large AVMs 83.3% and 33.3%. The results of microsurgical removal of cerebral AVMs can still be considered superior to the results of stereotactic radiosurgical treatment available from the literature-even for small AVMs. This is due to immediate exclusion of the AVM under direct local control of the angioarchitecture and thereby a reduced risk of secondary hemorrhaging and a decreasing morbidity rate with increasing time after the operation. Radiosurgical treatment requires a 2-year latency period for obliteration and carries a mortality rate of up to 12.5% and a rate of unexpected side effects of up to 20%. This treatment should be reserved for small, deep, surgically inaccessible AVMs or used as part of a multimodality treatment regimen consisting of partial embolization, partial excision and consecutive radiation of the residual nidus in initially very large AVMs. Embolization therapy-such as radiosurgery-carries a significant risk of morbidity (8%) and a mortality rate of up to 6%. It should only be considered for AVMs that are expected to be fully obliterated afterwards, or for primary inoperable AVMs that are to be changed into operable ones by embolization. Size reduction of otherwise operable AVMs does not justify the additional risk of embolization. Close collaboration of the specialties involved is desirable.     

Characterization of differing effects caused by homeopathically prepared and conventional dilutions using cytochrome P450 2E1 and other enzymes as detection systems

Determination of cytochrome P450 2E1 activity was carried out via hydroxylation of the synthetic substrate p-nitrophenol to p-nitrocatechol. Crude microsomal preparation isolated from rat liver served as source for cytochrome P450 2E1. Under assay conditions guaranteeing a linear course of the reaction the cytochrome P450 2E1 was stimulated in the presence of a 10(-6) dilution of As2O3 corresponding to 0.915 microM final concentration compared with control. All other concentrations of As2O3 used inhibited the enzyme activity more or less drastically. Furthermore, we used this enzyme system to study the influence of arsenicum album (As2O3) and potassium cyanatum (KCN) in homeopathically prepared (i.e., by consecutive 1:10 steps) and conventional dilutions. We found significant differences between the effects caused by homeopathic potencies (D) and equally concentrated dilutions on catalytic activity of cytochrome P450 2E1. Such differing effects were observed in the case of arsenicum album (As2O3) between D4/10(-4) and D6/10(-6) and in the case of potassium cyanatum (KCN) between D6/10(-6) and D12/10(-12). When we used glutathione-S-transferases and uricase we also found different effects mediated by potencies and conventional dilutions. The results obtained suggest that these three enzyme systems are appropriate detection systems to hunt out differing effects of differently prepared dilutions of specific test substances.     

Expert statement and assessment of medical impairment in work-related pulmonary disease

The Norwegian Societies of Thoracic Medicine and Occupational Medicine established a working group to standardise diagnostic procedures and evaluation of work-related respiratory disorders. In cases of suspected work-related diseases the physician may be asked by the National Insurance Administration or an insurance company to make a statement which will be one of the documents used to decide the patient's right to compensation benefit. We discuss the role of the physician as an independent expert. This is different from his role as clinician. The statement should include a balanced presentation of information from different sources, including health and occupational history, and the employer's information about the work environment (quantitative and qualitative exposure data). The statement must also include the results of a clinical examination and an assessment of functional status based on objective tests. The paper contains recommendations for evaluation of permanent impairment in light of the present Norwegian laws and regulations.     

Manufacture of films displaying liquid-crystalline structure

Reported is an attempt to attain orientation of macromolecules during extrusion of films of cellulose derivatives that led to the liquid-crystalline state of a polymer and resulted in enhanced film strength.     

Comparison of smoothness evaluation devices for power cablecompounds

A variety of data from different devices has been generated on the smoothness of shield products, but no direct comparison of compound smoothness for the devices themselves has been made. The purpose of this study was to compare four different methods for evaluating the smoothness of power cable compounds. The methods compared include: image analysis, laser scanning, mechanical profilometry and photomicroscopy with visual rating. Extruded tape samples of conductor shields, filled insulations and strippable shields were evaluated     

A bidding decision index for construction contractors

Results from applying the model on a sample of contractors, the majority of whom were international and operating in Egypt, reinforces the credibility of the developed methodology, claim the authors.     

High throughput VLSI DSP using replicated finite rings

This paper discusses strategies for implementing DSP systems using residue replication. The theory, recently introduced by two of the authors, uses formal polynomial ring mappings, from binary representations, to direct product ring implementation of integer processing arrays. The mapping produces completely independent computational arrays each computing over the same ring. This paper describes an architecture and processing array to implement, and take advantage of, the special computational ring structures that result from the mapping. A brief review of the theory and mapping techniques, is followed by the discussion of the architecture and VLSI design of an efficient inner product processing array using Fermat Primes.     

Interactions of histaminergic and serotonergic neurons in the hypothalamic regulation of prolactin and ACTH secretion

Serotonergic and histaminergic neuronal systems are both involved in mediation of the stress-induced release of the pituitary hormones prolactin (PRL) and ACTH. We investigated the possibility of an interaction between serotonin (5-HT) and histamine (HA) in regulation of PRL and ACTH secretion in conscious male rats. Animals were pretreated systemically with antagonists to 5-HT1, 5-HT2 or 5-HT3 receptors prior to intracerebroventricular (icv) administration of HA. The 5-HT1 + 2 receptor antagonist methysergide prevented and the 5-HT2 receptor antagonist LY 53857 attenuated the HA-induced PRL release while the 5-HT3 receptor antagonist ondansetron had no effect on this response. None of the three 5-HT receptor antagonists affected the ACTH response to HA. Specific blockade of HA synthesis by alpha-fluoromethylhistidine or blockade of postsynaptic HA receptors by icv infusion of the H1 receptor antagonist mepyramine or the H2 receptor antagonist cimetidine inhibited the PRL response to 5-HT or to the 5-HT precursor 5-hydroxytryptophan (5- HTP) given in combination with the 5-HT reuptake inhibitor fluoxetine (Flx). Blockade of the histaminergic system had no effect on the ACTH response to serotonergic stimulation. The H3 receptors are inhibitory HA receptors. Systemic pretreatment with the H3 receptor agonist R(alpha)methylhistamine, or the H3 receptor antagonist thioperamide had no effect on the hormone response to activation of the serotonergic system by 5-HTP plus Flx. We conclude that the serotonergic and histaminergic neuronal systems interact in their stimulation of PRL secretion, but not in their stimulation of ACTH secretion. This interaction involves serotonergic 5-HT1 and 5-HT2 receptors and histaminergic H1 and H2 receptors. Furthermore, the previously observed inhibitory effect of the H3 receptor agonist R(alpha)methylhistamine on stress-induced PRL and ACTH release seems not to be exerted by activation of presynaptic H3 receptors located on serotonergic neurons but rather on histaminergic neurons.