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.     

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.     

Importance of Growth Hormone for Blood Glucose Regulation Following Insulin-induced Nocturnal Hypoglycemia in Insulin-dependent Diabetes Mellitus

ABSTRACT The effect of growth hormone (GH) on the glucose homeostasis following nocturnal hypoglycemia was studied between 4 a.m. and noon in eight male patients with insulin-dependent diabetes mellitus (IDDM) by a somatostatin (250 μg/h)-insulin (0.4 mU/kg/min)-glucose (6 mg/kg/min)-infusion test (SIGIT). The patients participated in two experiments in which hypoglycemia at 4 a.m. was induced by i.v. insulin (1.5 mU/kg/min). In both experiments the endogenous secretion of GH was suppressed by somatostatin (250 μg/h) and glucagon (0.5 ng/kg/min) was given as substitute for the somatostatin-induced suppression of endogenous glucagon secretion. GH (20 mU/kg/h) or saline was given for 60 min from nadir blood glucose in random order. Mean nadir glucose values were the same in both studies (1.7 ± 0.2 vs. 1.7 ± 0.1 mmol/l) and no differences were registered in plasma-free insulin, glucagon and the responses of adrenaline and Cortisol to hypoglycemia. The infusion of GH resulted in plasma GH levels of about 50 μg/l at the end of the infusion, thereafter decreasing to low or immeasurable levels within 2 hours. Infusion of GH evoked a marked hyperglycemia within 4 hours. It is concluded that when hypoglycemia is accompanied by a transient increase in plasma GH, insulin resistance occurs after a lag period of approximately 4 hours and that this effect persists for at least another 4 hours.     

Humoral leukocyte adherence inhibition response in patients with oral cancer

Abstract – Antitumor immunity was assessed in a group of 10 patients suffering from squamous cell carcinoma of the oral cavity using the humoral leukocyte adherence inhibition assay (H-LAI). A tumor extract from a person with cancer of the tongue was used as antigen. Sera from five patients with carcinoma of the tongue were all positive in the test. Of the other five patients, three had cancer of the lips while in two patients the type was unspecified. All patients except one with cancer of the lips gave a positive response in the test. Thus, of the 10 patients with carcinoma of the oral cavity, nine responded. Among nine controls, one person gave a positive response.     

The Many Faces of Goodpasture's Syndrome

ABSTRACT Four cases of antiglomerular basement membrane (antiGBM) antibody mediated disease with unusual features are presented. Lung involvement was absent in one patient whereas the other 3 had Goodpasture's syndrome. Recognition of the nature of the disease was delayed in all cases, due to occurrence during pregnancy in one case and due to the indolent course of the renal injury in the other 3 cases. The therapeutic approach to these variant forms of antiGBM antibody mediated disease is discussed.     

Corrosion of non –γ2– amalgams

Abstract – Abstract– Eight different dental amalgams were studied in an in vitro corrosion test. Cylindrical test specimens were stored in weak lactic acid solutions at different pH for 1 month. The concentrations of mercury and copper in the solutions were measured and corrosion depths estimated. The results indicated that more copper was released from non - γ₂ - amalgams compared with conventional ones. The amounts of copper from these amalgams were not directly correlated to the concentration in the alloys. Mercury was released in much lower amounts than copper for all amalgams and seemed to originate from the γ₁-phase. A low pH promoted the corrosion.     

Dental caries and diet in an Alaskan Eskimo population

abstract – The diet and the prevalence of dental caries in a group of Alaskan inland Eskimos have been studied on two occasions. Considerable changes in living habits had occurred during the 8–10 intervening years. A marked change in diet was noted. The percentage of total calories obtained from protein had decreased by about 50 % and that from carbohydrate increased by nearly 50 %. The change in diet was accompanied by a drastic increase in the prevalence of dental caries. The DMFT rate for primary teeth showed an almost 90 % increase and the DMFT rate for permanent teeth of persons over 6 years of age exhibited a four-fold increase. The most dramatic change was observed in individuals 30 years of age or older. In this previously caries-free group, all subjects had developed caries in the course of 8 years.     

Corrosion of amalgams with special regard to zinc

Abstract – Five dental amalgams were studied in an in vitro corrosion test. Cylindrical test specimens were stored in weak lactic acid solutions at different pH for 1 month. The solutions were analyzed for zinc, the specimens were inspected and examined in SEM. The results showed that zinc was dissolved rather quickly from the amalgams and the amount was highest for the conventional one. Some amalgams had a low tendency for corrosion products to adhere to the surfaces. The presence of zinc did not seem to reduce their corrosion resistance.     

Antibodies against lipopolysaccharide from Bacteroides gingivalis before and after periodontal treatment

Abstract – Specific serum antibody activities of the IgG, IgA and IgM isotypes against lipopolysaccharide (LPS) prepared from Bacteroides gingivalis were measured by an enzyme-linked immunosorbent assay (ELISA) in a group of 12 periodontally healthy subjects and a group of 26 patients with periodontitis. The latter group received periodontal therapy, completed within about 1 yr. A serum sample was obtained from each participant at the first periodontal examination; a second sample was taken about 2 yr later. The mean antibody levels calculated for the healthy group did not change significantly between the first and second examination. The correlation coefficients computed between the two sets of measurements were 0.93, 0.90 and 0.96 for IgG, IgM and IgA respectively ( P < 0.05). Periodontal treatment significantly improved the clinical status of the patients and was followed by a statistically significant mean reduction in specific antibody levels to the LPS preparation (IgG: 15%, IgA: 30% and IgM: 15%).