Characterization of the prostanoid receptors and of the contractile effects of prostaglandin F2a in human pial arteries

The contractile and relaxant effects of various prostanoids were studied on isolated human pial arteries. Contractions were elicited with the following order of potency: U46619?U44069>PGB₂>PGF_2a>PGE₂?PGD₂>PGF_1a≥TXB₂, indicating that prostanoid-induced contractions probably are mediated by a thromboxane-sensitive receptor. Relaxation of PGF_2a-contracted arteries was induced with the order of potency: PGE₂> PGE₁>PGD₂?PGD₁. Vessels contrated by K⁺ were relaxed only by PGE,. Since PGI₂ was previously found to be more potent than all the prostanoids tested in the present study, relaxant responses are probably mediated via a PGI₂-sensitive receptor. The roles of free extracellular and cellularly bound calcium for the contractile effects of PGF_2a and K⁺ were estimated by incubating the arteries for various times in calcium-free medium containing 10^-5 M EGTA. Incubation for 5–10 min abolished K⁺-induced contractions, whereas after 40 min of incubation PGF_2a still induced contractions that reached 70% of control. The PGF_2a-induced contraction was biphasic in 8 out of 10 preparations. The second phase could be eliminated by increasing the EGTA-concentration to 10^-4 M, as well as by nifedipine pretreatment. In calcium-free, high K⁺ medium calcium-induced contractions were elicited at lower concentrations in the presence of PGF_2a. The results suggest that PGF_2a-induced contractions in human pial arteries are relatively independent of free extracellular calcium. PGF_2a may promote trans-membrane influx of calcium, as well as release calcium from seemingly superficially located cellular stores.     

Capillary permeability in healthy males with different insulin response to glucose

The capillary permeability in human skeletal muscle, expressed as capillary diffusion capacity (CDC) for 51Cr-EDTA, was determined during exercise with a local clearance method in two groups of healthy male subjects: a younger group with a mean age of 30 years and an older one with a mean age of 58 years. The main finding was that, in both age groups, CDC was significantly negatively correlated to the early phase of insulin response to an intravenous glucose load. No correlation was found between CDC and peripheral insulin sensitivity. CDC was significantly higher in the older age group (P less than 0.01) independent of insulin response, blood flow and body weight. These data indicate that subjects with low insulin response to glucose have a higher capillary permeability than high responders, and that muscle capillary permeability increases with age.     

Do women with epilepsy have increased frequency of menstrual disturbances?

PROBLEM: Menstrual disorders, reduced fertility and sexual problems seem to be more frequent in women with epilepsy than in the general population. Most investigations concerning menstrual disturbances in epilepsy patients, however, are small and based on selected materials. We therefore wanted to investigate the frequency of menstrual disturbances in a large, unselected population of epilepsy patients. METHODS: A retrospective, questionnaire study of a cohort of female outpatients, aged 18-45 was conducted. Each patient chose a close female friend who served as control, to optimise matching regarding age and lifestyle. RESULTS: Answers were received from 265 patients and 142 controls. Menstrual disturbances were more frequent in patients with epilepsy (48.0%) than in controls (30.7%) (P=0.004). Menstrual disturbances were more frequent in patients on polytherapy versus monotherapy (P=0.049) and more frequent in patients with high seizure frequency (>5seizures/year) compared to patients with a lower seizure frequency or those seizure free (P=0.006). The frequency of menstrual disturbances was higher in patients on valproate compared to carbamazepine monotherapy (P=0.045). CONCLUSION: This investigation confirms that women with epilepsy have an increased frequency of menstrual disturbances compared to women without epilepsy. In women with high seizure frequency and in those on polytherapy, the frequency of menstrual disturbances are further increased. The highest frequency of menstrual disturbances occurred in women using valproate.     

Effect of Distance on the Power Density from Two Light Guides

Purpose: This study determined the effect of distance on the power density from standard and Turbo light guides (Demetron/Kerr, Danbury, Connecticut). Materials and Methods: Power density was measured from 0 to 10 mm away from the tip of standard 8‐mm curved light guides and 13/8‐mm Turbo curved light guides. To determine the effect of distance on power density, a polynomial regression line was fitted. The Kolmogorov‐Smirnov (K‐S) statistic and the Wilcoxon rank sum (WR) tests were used to determine if there was a difference in the rate at which the power density decreased for the standard and Turbo light guides as the distance from the tip increased. Photographs of the light dispersion from each tip were also taken. Results: At 0 mm, the mean (± SD) power density from the two standard light guides was 743 ± 6.1 mW/cm² and from the four Turbo light guides was 1128 ± 22.1 mW/cm². As the distance from the tip of the light‐guide tip increased, the power density decreased, but the rate of decrease was greater from the Turbo light guides than from the standard light guides. At 6 mm the power density from the standard light guides fell to 372 mW/cm² (50% of the original value) and the power density from the Turbo light guides fell to 263 mW/cm² (23% of the original value). Both the K‐S statistic and the WR sum test indicated that the distribution of light intensities was significantly different from the two light guides (WR p‐value = .0246, K‐S p‐value < .0001). The two estimated polynomials intersected at 3.66 mm, and the 95% prediction intervals intersected at about 2.8 and 4.8 mm. Therefore, beyond 5 mm away from the tip of the light guide, the standard light guides gave higher power density readings than the Turbo light guides. Photographs showed that the light dispersed at a wider angle from the Turbo light guides than from the standard light guide. CLINICAL SIGNIFICANCE The design of the light guide of a light curing unit affects light dispersion, power density, and ultimately the dentist's ability to properly cure composite. For these reasons, manufacturers should report the power density at the tip of the light guide and 6 mm from the tip of the light guide, since significant differences exist between light guide designs.     

Fluorescence from dentin and cementum in human mandibular second premolars and its relation to age

Abstract – Investigations were carried out to study the fluorescent properties of human dentin and cementum and their relation to age. One hundred mandibular second premolars were ground according to the "half tooth" technique. The intensity to the red fluorescence was measured during illumination of dentin and cementum with a green light. The results were analyzed with the use of the SPSS. The intensity of the fluorescent light recorded from cementum was stronger than that recorded from dentin. A paired t -test showed no statistically significant left/right difference in fluorescence. Pearson's correlation coefficient indicated a strong relationship between age and fluorescence from dentin (r = 0.73) and from cementum (r =0.77). The sex of the individual had no significant influence on the fluorescence. Teeth removed from decreased individuals emitted fluorescence with a slightly stronger intensity than did teeth extracted from living patients. Regression analysis indicated a linear relationship between age and the fluorescence from either dentin or cementum. There was strong correlation between the intensity of the fluorescence and color estimates from the same teeth and the partial correlation coefficient was still statistically significant whtn controlling for the effect of age.     

Studies on the biosynthesis of albumin and proteins in human liver tissue

Abstract. The incorporation rate of leucine into albumin and the incorporation rate of leucine into hepatic proteins were determined in human liver tissue slices.
Leucine was linearly incorporated into hepatic tissue albumin, into albumin released into the incubation medium, and into hepatic proteins during 4 h incubation. Amino acids stimulated the albumin and hepatic protein synthesis in vitro and in vivo . The incorporation rate of leucine into hepatic albumin and tissue proteins was correlated to hepatic RNA concentration.
In twenty-one experiments the mean incorporation rate of leucine into hepatic tissue immunoreactive albumin was 5.1±0.6 μmol leucine h^-1 g albumin^-1 (mean±; SEM), and 0.87±;0.17 μmol leucine h^-1 g albumin^-1 into albumin released to the incubation medium. By crossed immunoelectrophoresis, the hepatic immunoreactive albumin could be partly resolved into two components one of which migrated at the same rate and the other at a lower rate than serum albumin. Treatment of the slowly migrating component with a low concentration of trypsin changed its mobility to that of serum albumin. Gel filtration through Sephadex G-100 of the slowly migrating fraction showed that it had similar molecular size as that of serum albumin. The results support the hypothesis that human hepatic albumin biosynthesis involves a polypeptide precursor similar to that described for the rat liver.     

A methodological study of errors in vertical measurements of edentulous ridge height on orthopantomographic radiograms

The purpose of this methodological investigation was to study the relative magnitude of the various errors in vertical ridge measurements from orthopantomograms of edentulous patients. The study was divided into two parts, Part I and Part II. Part I included eleven patients. Two standard orthopantomograms were taken of each patient. Part II included five of the eleven patients in Part I. Here, a third X-ray taken with the mouth open was added to the X-rays from Part I. The X-rays were traced by three dentists. Twelve vertical measurements in the maxilla and in the mandible were made. The variance produced by the patients (morphological variance) and those produced by the dentist, the X-ray, the interaction patient-dentist, the interaction dentist-X-ray and the random variance (methodological variances) were separately estimated on the basis of a three-way mixed analysis of variance model. In Part I, on the average, the sum of the methodological variances constituted 1·7 % and 2·5 % of the total variance in the maxilla and in the mandible respectively. The X-ray produced the greatest single variance component, averaging 1·1 % in both jaws. Although generally statistically significant, the remaining methodological variances were of low magnitude. The interaction patient-dentist, however, was not significant in most cases. In Part II, on the average, the sum of the methodological variances increased to 38·8 % in the maxilla and 4·6 % in the mandible, mainly caused by an increase in the variance produced by the X-ray.     

Effects of prostanoids on isolated feline cerebral arteries

The roles of extra-and intracellular calcium for the contractile effects of PGF_2α in the feline basilar artery (BA) were investigated. Comparisons were made with contractions induced by K⁺ and noradrenaline (NA). Addition of nifedipine to PGF_2α-or K⁺ (124 mM)-contracted arteries resulted in an incomplete relaxation, whereas NA-contracted vessels were completely relaxed. Incubation of the preparations in a calcium-free medium containing 10^-5 M EGTA for 5–10 min almost abolished contractions induced by K⁺ and NA. In contrast, 63 % of the response to PGF_2α remained after pretreatment of the arteries in a calcium-free solution for 40 min; PGF_2α produced a biphasic contraction in 17 out of 20 preparations consisting of a rapidly developing initial phase followed by a second increase in tension after 1–6 min. The second phase was absent if the EGTA-concentration was increased to 10^-4 M, or if the arteries were pre-treated with nifedipine. After incubation of the arteries in a calcium-free medium for 40–120 min and K⁺-depolarization, re-addition of calcium elicited contractions at lower concentrations in the presence of PGF_2α than in controls. The results suggest that PGF_2α-induced contractions in the feline BA are considerably less dependent on extracellular calcium than contractions evoked by K⁺ or NA. PGF_2α appears to be able to release calcium from two cellular stores, and may also promote calcium influx through the cell membrane.     

Treatment of Oral Theophylline Poisoning

ABSTRACT Two patients, 15 and 20 years old, were admitted after an overdose of theophylline in a slow-release preparation. The gradual occurrence of clinical symptoms reflected the slow gastrointestinal absorption of the drug, and therefore active treatment was not started until 10 and 12 hours after intake, respectively. Peak s-concentrations were 275 and 1295 μmol/l, respectively. One patient was treated with hemoperfusion only, whereas the more severely intoxicated patient was treated with combined hemoperfusion and hemodialysis. Only about 0.2 g theophylline was eliminated by hemodialysis in this patient compared to a calculated amount of 6.9 g by hemoperfusion. Severely theophylline-intoxicated patients should be treated with supportive therapy and hemoperfusion.