Comparison of histamine assay methods in measuring in vitro-induced histamine release in patients with allergic rhinitis

histamine release tests using whole blood were applied in testing in vitro Type I birch allergic reaction in two patients with allergic rhinitis. Heparinized blood was incubated with varying dilutions of allergen for 30 min at +37 degrees C. After centrifugation of the blood, plasma was separated and the liberated histamine was analysed by histamine radio enzyme assay (REA), high performance liquid chromatography (HPLC) with post-column derivatization system or radio immuno assay (RIA), and the results obtained by these methods were compared. REA and HPLC gave similar results, while RIA gave somewhat higher values, but was less sensitive.     

Tissue distribution, metabolism, and excretion of 14C-TCDD in a TCDD-susceptible and a TCDD-resistant rat strain

A comparative study was carried out in the most TCDD-resistant [Han/Wistar (H/W), LD50 greater than 3000 micrograms/kg] and the most TCDD-susceptible [Long-Evans (L-E), LD50 about 10 micrograms/kg] rat strain to assess the significance of kinetic factors in TCDD toxicity. Young adult males of both strains were administered 5 micrograms/kg (1.9 microCi/kg) 14C-TCDD intraperitoneally. Four rats per strain were killed at 4 hr, 1, 4, 8, 16, and 32 days after exposure. A total of 22 tissues along with blood and serum were sampled for liquid scintillation counting. From half of the animals, daily urine and faeces were also analyzed. In addition, 3 rats per strain were given 50 micrograms/kg (19 microCi/kg) 14C-TCDD and prepared for whole-body autoradiography after 1, 4 or 8 days. The livers of two rats per strain killed at 4 hr, 4 or 16 days, and the excreta from two rats of both strains collected on days 1-4, 5-8, 13-16, and 29-32 after exposure were analyzed for metabolites of TCDD by high pressure liquid chromatography. The label was mainly excreted in faeces as metabolites of TCDD, and the half-life of elimination was 20.8 (L-E) or 21.9 (H/W) days. A very similar overall distribution pattern was observed in both strains irrespective of dose, and the liver was the major site of accumulation. Practically all liver 14C-activity was found as the parent compound. Moderate strain-related differences were observed in the thyroid, thymus, prostate, adrenals, and brown and white fat, where lower values were recorded in H/W rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increase of specific symptoms after long-term use of chlorophenol polluted drinking water in a community

Chlorophenols contaminated the drinking water system and a local lake in the village of Järvelä in southern Finland. Period prevalence rates of symptoms, signs and diseases among the residents 15 years or older who responded (69%) to a survey in the contaminated area (1773 subjects) were compared with the rates of three uncontaminated areas (2018 subjects). Gastrointestinal and skin symptoms, in particular, were significantly (p < 0.05) more common in the contaminated area than in each control area. Nausea, general malaise, headache, anorexia, exceptional tiredness, and respiratory infections were significantly increased compared to the control areas combined. A dose–response was also observed: higher consumption of drinking water and contaminated fish further significantly increased (p < 0.05) reported symptoms. In conclusion, long-term use of chlorophenol polluted household water and fish can cause symptoms already familiar in connection with occupational chlorophenol exposures.     

Intestinal luminal microdialysis: a new approach to assess gut mucosal ischemia

BACKGROUND: The authors developed a microdialysis method for sampling lactate from the gut lumen to evaluate the metabolic state of the intestinal mucosa. The aim of the study was to evaluate the method in vivo during nonischemic systemic hyperlactatemia and gut ischemia. METHODS: Microdialysis capillaries were inserted in the lumen of jejunum, in the jejunal wall, and in the mesenteric artery and vein in anesthetized, normoventilated pigs. In the first experiment, infusion of lactate was used to clamp the arterial blood lactate at 5 mM and 10 mM (n = 6). In the second experiment, 90 min of intestinal ischemia was induced by total (n = 6) or partial (n = 6) occlusion of the superior mesenteric artery followed by 60 min of reperfusion. Sham-operated animals were used as controls (n = 6). RESULTS: Gut luminal lactate increased only slightly during the nonischemic hyperlactatemia: from a median baseline value of 0.10 (range, 0.06-0.28) to 0.50 (range, 0.15-1.18) and 0.86 (range, 0.35-2.05) mM. Total occlusion of superior mesenteric artery increased luminal lactate from a median of 0.09 (range, 0.06-0.17) to 2.37 (range, 1.29-2.98) and further up to 3.80 (range, 2.55-6.75) mM during reperfusion. Partial occlusion of superior mesenteric artery induced an increase from a median of 0.09 (range, 0.06-0.51) to 1.66 (range, 0.07-3.97) mM. Gut wall microdialysate lactate in deep and superficial layers followed the arterial and mesenteric vein microdialysate lactate. CONCLUSIONS: Luminal lactate concentration, as measured by microdialysis, increases substantially during gut ischemia but does not respond to systemic hyperlactatemia per se. In contrast, gut wall microdialysis cannot distinguish between gut ischemia and systemic hyperlactatemia. Gut luminal microdialysis provides a method for the assessment of intestinal ischemia with a potential for clinical application.     

Liver tumor-promoting activity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in TCDD-sensitive and TCDD-resistant rat strains

Risk assessment of dioxins is currently based on induction of liver tumors in rats. The toxicity of dioxins is characterized by large sensitivity differences among animal species and even strains of the same species, which complicates the risk assessment. The significance of these differences in dioxin-induced carcinogenicity is not known. We therefore studied the liver tumor-promoting activity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the sensitive Long-Evans (L-E) and the resistant Han/Wistar (H/W) rats differing >1000-fold in their sensitivity to the acute lethaity of TCDD. Female rats were partially hepatectomized, initiated with nitrosodiethylamine, and treated with TCDD for 20 weeks. Altered hepatic foci (AHF) were stereologically quantitated using glutathione S-transferase P as a marker. AHF were significantly (P < 0.001) and dose dependently increased in L-E rats at 10 and 100 ng/kg/day, but in H/W rats only at 1000 ng/kg/day and above, indicating a remarkable (approximately 100-fold) sensitivity difference between L-E and H/W rats. The same sensitivity difference but 10-fold less foci were observed between nonhepatectomized/noninitiated L-E and H/W rats. Induction of AHF was related to hepatotoxicity but not to cytochrome P4501A1 activity in the liver. Liver TCDD concentrations were similar in both strains. H/W rats are exceptionally resistant to induction of AHF by TCDD, and the resistance is associated with an altered transactivation domain of the aryl hydrocarbon receptor. Genetic differences may account for significant interindividual/intraspecies sensitivity differences in dioxin-induced carcinogenesis. Understanding the role of transactivation domain of the aryl hydrocarbon receptor in carcinogenesis is therefore likely to improve dioxin risk assessment.     

Cost‐effectiveness of CT thorax and bronchoscopy in haemoptysis with normal CXR for exclusion of lung cancer

As fibre‐optic bronchoscopy and CT thorax become more widely used, patients with haemoptysis who had normal CXR and sputum results are more commonly offered both CT and bronchoscopy to exclude lung cancer. Doctors who are under possible litigation pressure arising from missed diagnoses of lung cancer are often exhaustive in their investigations, even when the haemoptysis has been transient. The present study aims to investigate the number of cancer patients who can be detected with the two investigations, and compare recent similar study results with archive results. We found that despite the use of more efficient investigation tools, the yield is paradoxically much lower and, hence, less cost‐effective than that of previous studies. The likely reason is that doctors tend to over‐investigate, even for short‐term, minimal blood‐streaked sputum, which is common among simple bronchitis. In order to be more cost‐effective, these investigations should be used more selectively and for high risk patients such as those with prolonged haemoptysis and those who are heavy smokers.     

Obstetric outcome of teenage pregnancies

A retrospective cohort study was performed in a tertiary centre to determine if teenage nulliparas (aged alpha19 years, study group) had higher incidences of instrumental and Caesarean deliveries compared with nulliparas aged 20-34 years (control group) selected from the first women in the birth registry who delivered after each study case and satisfying the criteria for controls. The hospital records of the study and control cases were retrieved for review. Comparison was made in the maternal demographics, major antenatal complications, outcome of labour, mode of delivery, and perinatal outcome. In the study group, maternal height was similar but the body mass index was lower. Although the mean birthweight was lower and the incidences of preterm labour and small-for-gestational-age infants higher, there were also increased incidences of large-for-gestational-age and macrosomic infants. While there was no difference in the types of labour, there were fewer Caesarean and instrumental deliveries, a finding that persisted even after excluding the preterm deliveries. Lastly, teenage mothers aged <17 years had similar outcomes to those aged 17-19 years. These results indicated that teenage mothers had better obstetric outcomes, despite the higher incidence of preterm labour, and that young adolescents (<17 years) performed as well as their older peers.      

Endothelium-dependent relaxation and effects of prostacyclin,endothelin and platelet-activating factor in human hand veins and arteries

An altered release of endothelium-derived vasoactive factors has been implicated in several vasospastic conditions. Since the functional role of the endothelium in the hand vasculature is largely unknown, we examined the effects of ‘endothelial removal’ on vascular reactivity, and the effects of some ‘endothelium-associated’ substances in isolated human hand veins and arteries. Acetylcholine induced a large relaxation (E_max= 97±1 %) in precontracted hand arteries. The relaxation was abolished by endothelial removal. In hand veins, acetylcholine induced a small relaxation (E_max= 13 ± 4%), which was unaffected by endothelial removal. An endothelium-dependent relaxation was, however, obtained with high concentrations ( 10^-6 mol 1^-1) of the Ca²⁺ ionophore A23187. Contractile responses to noradrenaline, serotonin and prostaglandin F_2x did not differ between vein segments with and without endothelium. Endothelin was a potent constrictor of both veins and arteries. The potency and maximum response did not differ between the two types of vessel. Indomethacin pretreatment of veins did not influence the endothelin-induced contractions, suggesting that cyclo-oxygenase products are not involved in the response. In endothelin-contracted veins and arteries, the prostacyclin analogue iloprost elicited relaxation of similar potency and amplitude. The maximum relaxation in veins was, however, 3 times larger than that produced by prostacyclin itself. Platelet-activating factor was devoid of contractile and relaxant effects in both veins and arteries. The present study indicates differences between human hand veins and arteries regarding endothelial-dependent relaxation, and suggests that the modulatory role of endothelium-derived relaxing factor(s) is small in hand veins. The contractile and relaxant effects of endothelin and iloprost, however, did not differ between veins and arteries.     

Repeated hand urticaria due to contact with fishfood.

BACKGROUND: The etiology of urticaria is often difficult to determine. However, in case of repeated circumstance-connected urticaria, the reason may be easily clarifyable. CASE: A 51-year-old healthy woman repeatedly experienced occupational hand urticaria when handling fish food. An unexpected reason for the urticaria was found in that the fishfood contained histamine as a "contaminant". CONCLUSIONS: In fishfood batches, biological degradation can produce histamine and possibly other toxic substances that can lead to occupational health problems.