Effects of short-term high dose intake of evening primrose oil on plasma and cellular fatty acid compositions, α-tocopherol levels,and erythropoiesis in normal and Type 1 (insulin-dependent) diabetic men

Summary In addition to their usual diet, nine Type 1 (insulin-dependent) diabetic men and ten male control subjects took 20 g d,ga-tocopheryl acetate enriched evening primrose oil (14.45 g 182c,6, 1.73g 183c,6, 400 mg d,-tocopheryl acetate) daily for one week. At start, diabetic patients had more 140, 150 and 18 2c,6, and less 160, 161c,7, 181c,7, 183c,6, 203c,9, 203c,6, 204c,6 and 226c,3 in plasma, erythrocytes and/or platelets. Furthermore, they had lower 161c,7/160, 181c,7/160, and 204c,6/203c,6 ratios and a higher 203c,6/183c,6 ratio. In diabetic patients, -tocopherol levels in erythrocytes were lower, whereas those in plasma were normal. In both groups, oil intake changed fatty acid profiles. Most markedly, 203c,6 increased, whereas the ratios 203c,6/ 183c,6 and 204c,6/203c,6 decreased. 204c,6 increased in control subjects, but not in diabetic patients. Erythrocytes and platelets responded differently in their fatty acid profiles, -tocopherol rose in plasma and, although less for diabetic patients, in erythrocytes. In diabetic patients as well as in control subjects, erythrocyte count, haemoglobin level, mean corpuscular haemoglobin content and concentration increased and glycosylated haemoglobin percentage decreased without an apparent decline in blood glucose levels. Plasma -thromboglobulin and platelet factor 4 decreased, especially in diabetic patients. In conclusion, diabetic patients had abnormal fatty acid patterns, suggesting an impaired 9, 6 and 5 desaturation and an enhanced chainelongation, and had lower erythrocyte a-tocopherol levels; and short-term high dose intake of evening primrose oil increased 203c,6 in both groups, but 204c,6 only in control subjects, gave fatty acid responses which were different for erythrocytes and platelets, enhanced erythropoiesis, and lowered indices of in vivo platelet activation.     

Different ratio of myosin heavy chain isoforms in arterial smooth muscle of spontaneously hypertensive rats

Summary The relative proportion of the two putative heavy chains of smooth muscle myosin (MHC1 and MHC2) was determined in the caudal and femoral arteries of spontaneously hypertensive rats (SHR) and normotensive (WKY) rats at 16 weeks of age. The heavy chain polypeptides with M_r 204000 and 200000 were resolved electrophoretically under denaturing conditions in porous polyacrylamide gels. Both proteins reacted strongly with a monoclonal antibody (2C4) to smooth muscle MHC. In caudal arteries the ratio of MHC1/MHC2 was 3.11 in SHR rats compared with 1.81 in WKY rats (p<0.005) and similarly in femoral arteries, 2.81 vs 1.51 (p<0.001). In the portal vein there was no significant difference, 1.71 vs 1.51. The possibility that the higher MHC ratio in the SHR is the genetically mediated defect in arterial smooth muscle cells leading to the hypertension is discussed as an alternative to the elevated systemic blood pressure causing the altered MHC ratio.     

Risk of human immunodeficiency virus (HIV) transmission by anti-HIV-negative blood components in Germany and Austria

In order to estimate the residual risk of transfusion-transmitted HIV infection we have analyzed the data from two transfusion centers in Austria (Vienna) and Germany (Göttingen) from 1985 to 1994. In Vienna, an incidence of 142000 positive anti-HIV tests in repeat donors and a prevalence of 17000 in first-time donors were found in 1993. In Göttingen, the indicence was 167000 and the prevalence 17900 from 1985 to 1993. Based on a mathematical model which takes (a) the window period and (b) the false-negative rate of anti-HIV tests, as well as (c) human and operational errors into consideration, we have calculated the residual risk of HIV infection. The residual risk (third generation anti-HIV test) was found to be 1520000 (95% confidence interval 11340000-1210000), and 1900000 (95% confidence interval 12340000-1380000) for Vienna and Göttingen, respectively, in 1993. Look-back studies from 1985 till 1994 revealed transfusion-transmitted HIV infections in three recipients (for 1.9 million donations in Vienna) and one recipient (for 160000 donations in Göttingen) of blood components. Based on our model, as well as on prevalence and incidence rates of HIV infection, it is also possible to predict the efficacy of additional measures introduced to further decrease the risk of transfusion-transmitted HIV infection through blood components.     

Hypomagnesaemia in Type 2 (non-insulin-dependent) diabetes mellitus is not corrected by improvement of long-term metabolic control

Summary Low levels of magnesium have frequently been reported in diabetes mellitus especially in poorly controlled Type 1 (insulin-dependent) diabetic patients. Furthermore hypomagnesaemia might contribute to insulin resistance in Type 2 (non-insulin-dependent) diabetes. As the influence of improved metabolic control on plasma magnesium levels is unknown in Type 2 diabetic patients we studied magnesium plasma levels in 50 patients 1) before, 2) one and 3) three months after the initiation of insulin therapy or intensified treatment with oral hypoglycaemic agents. Magnesium plasma levels were measured by a colorimetric method and were significantly reduced in diabetic patients compared to healthy control subjects (0.79±0.01 mmol/l vs 0.88±0.01 mmol/l; p<0.0001). Metabolic control was significantly improved as documented by reduced HbA_1C levels in both insulin-treated patients or the patients on oral hypoglycaemic agents (p<0.003). However, plasma magnesium levels remained unchanged during the follow-up in the insulin-treated group (10.79±0.02 mmol/l; 20.81±0.02 mmol/l; 30.79±0.01 mmol/l) as well as in the patients on oral hypoglycaemic agents (10.79±0.03 mmol/l; 20.78±0.02 mmol/ l; 30.84±0.04 mmol/l). This study shows that even marked improvement of glycaemic control does not correct hypomagnesaemia in Type 2 diabetes. We conclude that hypomagnesaemia might be related to the insulin-resistant state and that possible beneficial effect of chronic magnesium administration should be evaluated in these patients.     

Ataxia associated with increased plasma concentrations of pristanic acid,phytanic acid and C27 bile acids but normal fibroblast branched-chain fatty acid oxidation

Summary Investigations of peroxisomal function were undertaken in an 8-year-old girl who developed motor difficulties at the age of 3.5 years and went on to develop a progressive ataxia and dysarthria. There were no other neurological abnormalities and she was of normal intelligence. Analysis of plasma very long-chain fatty acids revealed a normal C₂₆ concentration and normal C₂₄/C₂₂ and C₂₆/C₂₂ ratios. Analysis of branched-chain fatty acids showed an elevated plasma phytanic acid concentration of 60 µmol/L (normal<15) and a considerably elevated pristanic acid concentration of 50 µmol/L (normal<2). Plasma concentrations of the C₂₇ bile acids 3,7-dihydroxycholestanoic acid (DHCA) and 3,7,12-trihydroxycholestanoic acid (THCA) and of the C₂₉-dicarboxylic acid were also increased. We postulated that these results might be due to deficiency of the peroxisomal branched-chain acyl-CoA oxidase, but when oxidation of branched-chain fatty acids was studied in cultured skin fibroblasts it was found to be normal. Alternative explanations for the accumulation of branched-chain substrates for peroxisomal-oxidation are discussed. Treatment with a low-phytanic acid diet arrested the progression of the ataxia and led to a slight improvement.     

Effect of β-adrenergic stimulation on free fatty acid content in subepicardial and subendocardial layers of the dog heart in situ. Separation and assay by capillary gas chromatography

Summary The effects of -adrenergic stimulation produced by an infusion of isoproterenol (1 g·kg^–1 min^–1, 30 min) were studiedin situ in the anaesthetized dog placed under a total cardiopulmonary bypass. Samples of the subepicardial and the subendocardial layers were homogenized separately prior to the extraction and methylation of free fatty acids (FFA). Gas chromatography on Carbowax 20 M capillary columns was used for the quantitation of myristic (C 140), palmitic (C 160), palmitoleic (C 161), stearic (C 180), oleic (C 181), linoleic (C 182), and arachidonic (C 204) acids.Within 5 min, isoproterenol decreased the tissue content of FFA significantly. The decrease was more pronounced in the endocardial layer where the FFA concentration reached its minimum at the 5th or the 15th min. In the epicardial layer, all the FFA reached their minimal concentration at the 30th min of the isoproterenol infusion. In both layers, lactate content remained unchanged at 5 and 15 min and rose at the 30th min only and content in phosphorylated compounds (ATP, creatine-phosphate—CP) did not show any significant variation during the -stimulation period. A significant correlation was found between the chronotropic effect of isoproterenol and the reduction of FFA concentration.With the technical assistance of Agnès Bacconin.     

The influence of fish oil diet and norepinephrine treatment on fatty acid composition of rat heart phospholipids and the positional fatty acid distribution in phosphatidylethanolamine

Summary The effect of chronic norepinephrine (NE) administration with increasing dosage from 1–4 mg/kg over a period of 2 weeks was studied on cardiac phospholipids and their fatty acid distribution in rats. Animals were fed a control diet or a 10% cod liver oil (CLO)-enriched diet. The relative distribution of various polyunsaturated fatty acids esterified to the 1- and 2-position of the phosphatidylethanolamine fraction was estimated. NE stress during control feeding significantly reduced the total phospholipid content in rat heart. No differences in the phospholipid class distribution were found. However, CLO feeding as well as chronic NE administration resulted in a decrease of 3 fatty fatty acids, mainly C 18:2 6 and C 20:4 6, which was compensated with an increase in 3 fatty acids, mainly C 20:5 3 and C 22:6 3. The changes in fatty acid composition qualitatively agree with those reported by Gudbjarnason et al. (23), except that the mortality in our NE-treated control or CLO-fed groups was considerably lower. It can probably be attributed to a different mode of NE administration. On the other hand, at the end of the CLO feeding period in rats treated with NE or not, comparing with control fed rats without NE treatment, the incidence rate of ST segment elevation in electrocardiogram (ECG) recorded under light diethylether-induced anesthesia was higher. Independent of whether the fatty acid composition of myocardial phospholipids was dietary or pharmacologically manipulated, most of the polyunsaturated fatty acids were found at the 2-position of the phosphatidylethanolamine molecules. The polyunsaturated fatty acids account for 45–50% of the fatty acyl residues and preferentially occupy the 2-position, where they can exchange for each other.     

Solubility of calcium soaps of long-chain fatty acids in simulated intestinal environment

Calcium soaps of long-chain fatty acids are often referred to as being insoluble. These soaps make up most of the fecal lipid in infants fed high calcium diets and are responsible for increased fat malabsorption in patients with exocrine pancreatic insufficiency receiving enzymes and calcium carbonate antacids. We investigated the solubility of the calcium soaps of long-chain fatty acids in simulated human intestinal contents. Calcium soaps of the [¹⁴C]fatty acids of lauric (120), palmitic (160), stearic (180), and oleic acids (181) were synthesized. Individual soaps were incubated (1 hr at 37°C) in 140 mM NaCl solution containing 10 mM bile salts; 75% glycine conjugates (35% cholate, 25% chenodeoxycholate, 15% deoxycholate), and 25% taurine conjugates (12% cholate, 8% chenodeoxycholate, 5% deoxycholate) with 1.45 mM lecithin at various pHs ranging from 5.0 to 6.8. Soap solubility was assessed by analyzing the supernatant for radioactivity after centrifugation at 12,500g for 15 min. Fatty acids were uniformly more soluble than the respective calcium soaps. The solubility of the free fatty acid can be compared to its calcium soap by two methods: either as the total amount of fatty acid in solution or as the molar solubility of the fatty acid and the soap (a calcium soap molecule contains two fatty acid molecules). By molar solubility the free fatty acid was 13 times more soluble than the calcium soap, whereas comparison of the quantity of fatty acid in solution revealed an average of 6.5 times more free fatty acid than that present in the respective calcium soap. The solubility of the calcium soaps was negatively correlated with acid concentration [H⁺], carbon chain length (n), and fatty acid saturation. The solubility could be described by a multilinear regression (r=0.84) incorporating chain length and acid concentration as the independent variables; log soap solubility =–0.0379(n)–19298.2[H⁺]–0.074.     

A prospective study of local recurrence after resection and low stapled anastomosis in 183 patients with rectal cancer

Local recurrence is the most serious complication of anterior resection for rectal cancer, usually occurring during the first two years after surgery. Over a five-year period, from 1981 to 1986, 183 patients underwent anterior resection for rectal carcinoma at the Surgery Ward of the University of Ferrara. Patients were followed for two years postoperatively. All operations were performed with staplers and classified according to Dukes, with 43 cases of Dukes' A; 83 cases of Dukes' B; and 57 cases of Dukes' C. In the first 24 months after surgery, the tumor recurred locally in 44 of the 183 patients (24 percent. Dukes' stage, grading distal resection margin, and histopathologic differentiation of the distal rectal ring left in the stapler after anastomosis were assessed to determine a prognostic indicator for the recurrence of the tumor. The stage:recurrence ratio was as follows: A, 1 (2 percent); B, 21 (25 percent); and C, 22 (39 percent). The grading:recurrence ratio was: G1, 1351 (25 percent); G2, 24110 (22 percent); and G3, 722 (32 percent). The ratio between distal rectal resection margin and recurrence was: 0 to 2 cm, 1527 (56 percent); 2 to 4 cm, 1674 (22 percent); and over 4 cm, 1382 (15 percent). Histopathologic examination of the distal rectal ring was negative for all patients. These data confirm the direct relationship between class and local recurrence and indicate histologic grade and distal resection margin as significant prognostic parameters only when interpreted in the light of staging.     

Liver microsomal Δ6 and Δ5 linoleic acid desaturation in female BB rats

Summary Rat liver microsomal 6 and 5 desaturation are defective in experimental diabetes, but this defect is correctable with insulin treatment. Rat liver fatty acid composition and 6 and 5 desaturation were studied in the spontaneously diabetic adult female Bio-Breeding (BB) rat. Control Wistar rats and BB rats (4 weeks of diabetes), that received insulin (1 IU·100 g body weight^–1·day^–1), were killed 20 h after the last insulin injection. 6 and 5 desaturase activities were estimated from the incubation of liver microsomes with (1-¹⁴C) 18:2, n–6 or (2-¹⁴C) 20:3, n–6, respectively, and the fatty acid composition of the liver and microsomal liver lipids were investigated. Under experimental conditions 6 and 5 desaturase activities were unchanged in the BB rats when compared to the control rats. Impairment of the liver fatty acid composition of diabetic BB rats is not consistent with normal desaturase activity and may be explained by factors other than desaturation disturbance.     

Contrasting effects of treatment with ω-3 and ω-6 essential fatty acids on peripheral nerve function and capillarization in streptozotocin-diabetic ratsn

Summary Essential fatty acid metabolism is impaired by diabetes mellitus and this may be important in the aetiology of peripheral nerve dysfunction. The effects of -linolenic acid (-6) and fish oil (-3) alone, and in combination, on nerve function and capillarization were examined in 2-month streptozotocin-diabetic rats. Diabetes resulted in approximately 15% and 23% decreases in saphenous sensory and sciatic motor nerve conduction velocities, respectively (p<0.001). Motor and sensory conduction velocities were in the non-diabetic range after both preventive and reversal -6 treatment of diabetic rats (p<0.001). No significant changes occurred in -6 treated non-diabetic rats. Preventive -3 treatment was largely ineffective. Reversal treatment with a combination of -6 and -3 fatty acids was marginally effective and improved motor (p<0.05), but not sensory conduction velocity. In vitro measurement of sciatic nerve resistance to hypoxic conduction failure in diabetic rats revealed a 56% increase in the time taken for the compound action potential amplitude to be reduced by 80% (p<0.01) compared to non-diabetic rats. This was partially prevented by -6 treatment (29% increase, p<0.01). Reversal -6 treatment had a lesser effect (37% increase, p<0.05 compared to untreated diabetic rats). -3 treatment had no significant effect on conduction failure time. Sciatic endoneurial capillary density increased by 11% with preventive -6 treatment (p<0.05), but was unaffected by reversal -6 and by -3 treatments. These results demonstrate the specificity of -6 essential fatty acids in improving diabetic nerve function and highlight an antagonism exerted by -3 components, which may have therapeutic implications.     

Large-bowel cancer in the young: A national survival study

Large-bowel cancer in young patients is reported to be a more aggressive and advanced disease at presentation and is believed to be associated with a relatively poor prognosis. Of 2420 patients registered in New Zealand (1968 to 1970), 131 were under 40 years of age and 2289 were over 40 years of age. The annual average incidence of treatable colorectal cancer in patients under 40 years of age was 2.36 per 100,000 and 82.93 in patients over 40 year of age. There were predominantly more females in both age groups with colonic tumors, 5044 (femalemale), and 759652 (femalemale). The rectal tumor male-to-female ratio of 10.68 in those over 40 years of age was reversed in those under 40 years of age (12.08). There was no significant difference in the subsite distribution of colorectal cancers between the two groups. There was a higher proportion of Stage 1 tumors in those under 40 years of age and a correspondingly higher proportion of Stage 2 tumors in those over 40 years of age. The overall crude and relative five-year survival rates for patients under 40 years of age were both 60 percent, whereas the crude rate for older patients was 42 percent, with a corresponding relative rate of 53 percent. Ten-year survival rates were generally higher in younger patients. From this study, there was no evidence to suggest that younger patients (less than 40 years old) with colorectal cancer had worse prognoses and did not survive as long as older patients (40 years and over).Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Anaheim, California, June 12 to 17, 1988.     

Changes of platelet phospholipids in diabetes mellitus

Summary In the present study the phospholipid and fatty acid concentration of platelets has been measured in patients with poorly and well controlled diabetes mellitus and in control subjects. An increased phosphatidylethanolamine (p < 0.01) and phosphatidylserine (p < 0.001) content of platelets was found in poorly controlled diabetes as well as an increased phosphatidylserine (p < 0.001) concentration in well controlled diabetes. The most notable changes of platelet fatty acids were a decreased concentration of palmitic (160; p < 0.01) and linoleic acid (182; p < 0.001) in the poorly controlled diabetes as well as (p < 0.001) and (p < 0.025) in the well controlled diabetes, respectively. Also, an increased concentration of arachidonic acid (204; p < 0.001) was found in both groups of diabetics. No differences were found in phospholipid concentration between patients with and without vascular diseases.     

Effect of polyinosinic-polycytidylic acid on chemically induced tumorigenesis by methylcholanthrene in mice

Summary Polyinosinic-polycytidylic acid administered intraperitoneally inhibits the formation of chemically induced tumors by methylcholanthrene in mice. The experiments show that poly (IC) is an effective suppressor of tumor formation when given simultaneously with the cancerogenic compound, or soon thereafter (before 4 weeks). Once the tumorigenesis was started (after 8 weeks), poly (IC) treatment becomes ineffective.The mechanism of inhibition of tumor formation by poly (IC) was studied by measuring the immune response of treated mice. Mice treated with methylcholanthrene alone exhibit a 50% inhibition of the immune response towards sheep red blood cells. Animals injected with poly (IC) after the methylcholanthrene treatment did not show any significant change. However, a pretreatment with poly (IC) causes a complete reversal of immunosuppression caused by methylcholanthrene.

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Zusammenfassung Polyinosin-Polycytidylsäure (Poly IC), intraperitoneal verabreicht, hemmt die Bildung von chemisch induzierten Tumoren durch Methylcholanthren in Mäusen. Die Versuche zeigen, daß Poly (IC) ein wirksamer Hemmstoff der Tumorbildung ist, wenn es gleichzeitig mit Methylcholanthren oder bald danach (vor Ablauf von 4 Wochen) gegeben wird. Wenn die Tumorgenese einmal begonnen hat (nach 8 Wochen), wird die Poly (IC)-Behandlung unwirksam.Der Hemmungsmechanismus der Tumorbildung durch Poly (IC) wurde durch Messung der Immunantwort von behandelten Mäusen untersucht. Nur mit Methylcholanthren behandelte Mäuse zeigen eine 50%ige Hemmung der Immunantwort in Gegenwart von Schaferythrocyten. Behandelt man die Tiere zuerst mit Methylcholanthren und anschließend mit Poly (IC), so bleibt die Immunantwort unbeeinflußt. Ändert man diese Reihenfolge, indem das Poly (IC) vor Methylcholanthren eingespritzt wird, so wird die immunsuppressive Wirkung des Methylcholanthrens vollkommen aufgehoben.

     

Essential fatty acids in clinically stable children with propionic acidaemia

Disturbances of fatty acid metabolism with accumulation of odd-chain fatty acids have been reported in propionic acidaemia (PA). It is not known whether the synthesis of long-chain polyunsaturated fatty acids (LCPUFA) is also affected. In five clinically stable children with PA (median age 8 years, range 3.5-9.5 years; median percentage fibroblast propionyl-CoA carboxylase activity 0.8, range 0.8-1.5), we determined the fatty acid composition of plasma phospholipids, triglycerides and sterol esters and compared the results with those of 18 age-matched healthy controls. Odd-numbered fatty acids were found in all samples of PA patients but in controls median values were zero. Percentage contributions of substrate (linoleic acid, C18:2 -6) and principal product (arachidonic acid, C20:4 -6) of -6 LCPUFA synthesis did not differ between patients and controls. Similarly, there were no differences between both groups in the substrate (-linolenic acid, C18:3 -3) and principal product (docosahexaenoic acid, C22:6 -3) of -3 LCPUFA formation. We conclude that disturbances of fatty acid metabolism in clinically stable children with PA do not affect LCPUFA synthesis.     

The effect of dbcAMP on the lysolecithin induced hemolysis of calf and adult cattle erythrocytes

Summary The calf erythrocytes have an increased sensitivity against lysolecithin as compared to their adult counterparts. 10^–3M dbcAMP increases the hemolysis induced by 5g of lysolecithin in 0.15 M NaCl containing 10 mM phosphate buffer (pH 7.4). By increasing the level of phosphate buffer (75 mM) in the incubation mixture, 10^–3M dbcAMP decreases the hemolysis induced by 5g of lysolecithin. These data suggest a dual effect exerted by dbcAMP: the relatively labilizing or stabilizing effect prevails as a function of exogenous inorganic phosphate level.10-⁶M dbcAMP also has a relative protective effect against lysolecithin.The combined addition of cAMP (10^–3) and theophyllin (10^–4M) does not stabilize the membrane.By increasing the level of lysolecithin to 20g/ml the stabilizing effect of dbcAMP disappears.DbcAMP (10^–3) as well as cAMP (10^–3M) and theophyllin (10^–4M) have a minimum increasing effect on hemolysis in the absence of lysolecithin, too.

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Abbreviations dbcAMP N⁶-20-dibutyryladenosine 35-monophosphate - cAMP cyclic 35-adenosine monophosphate     

Effects of three avocado/soybean unsaponifiable mixtures on metalloproteinases, cytokines and prostaglandin E2 production by human articular chondrocytes

The in-vitro effects of avocado and soybean unsaponifiable residues on neutral metalloproteinase activity, cytokines and prostaglandin E₂ (PGE₂) production by human articular chondrocytes were investigated. Avocado and soybean unsaponifiable residues were mixed in three ratios: 12 (A1S2), 21 (A2S1) or 11 (A2S2). Freshly isolated human chondrocytes were cultured for 72 h in the absence or presence of interleukin-1 (IL-1) (17 ng/ml), with or without unsaponifiable residue mixtures at a concentration of 10 g/ml. A/S unsaponifiable residues were also tested separately at concentrations of 3.3, 6.6 and 10 g/ml. All A/S unsaponifiable mixtures reduced the spontaneous production of stromelysin, interleukin-6 (IL-6), interleukin-8 (IL-8) and prostaglandin E₂ (PGE₂) by chrondrocytes. At concentrations of 3.3 and 6.6 g/ml, A/S residues, tested separately, were potent inhibitors of the production of IL-8 and PGE₂. Nevertheless, only avocado residue inhibited IL-6 production at these concentrations. A/S unsaponifiable mixtures had a more pronounced inhibitory effect on cytokine production than avocado or soybean residues added alone. As anticipated, IL-1 induced a marked release of collagenase, stromelysin, IL-6, IL-8 and PGE₂. A/S unsaponifiable mixtures partially reversed the IL-1 effects on chrondrocytes. These findings suggest a potential role for A/S unsaponifiable extracts in mitigating the deleterious effects of IL-1 on cartilage.     

In vivo and in vitro test for growth potential of liver cells from rats during early stage of hepatocarcinogenesis by 3′-methyl-4-dimethylaminoazobenzene

Summary A rapid increase in the fraction of small liver cells was observed in the liver of rats during the early stage of hepatocarcinogenesis by 3-methyl-4-dimethylaminoazobenzene (3-Me-DAB). The change in cell population was represented by the decrease in glucose-6-phosphatase activity and by the increase in number of -glutamyltranspeptidase-positive cells. When DNA synthesis of liver cells from rats fed 3-Me-DAB was measured by autoradiography in primary culture, it began to increase 2 weeks after the start of the carcinogen feeding, reaching a plateau level after 3 weeks. Liver cells from rats fed 3-Me-DAB for 2 weeks or over demonstrated a remarkable resistance to the cytotoxic effect of the carcinogen (0.24 mM) in primary culture. Furthermore, liver cells from rats fed 3-Me-DAB for 3 weeks or over proliferated in the presence of the carcinogen in primary culture. When liver cells from 3-Me-DAB-fed and control rats were transplanted into syngeneic rat spleens, the former cells proliferated more vigorously than did the latter. The growth potential of liver cells from 3-Me-DAB-fed rats tended to be enhanced with time in the carcinogen feeding. Hepatocellular carcinomas developed in the host spleens implanted with liver cells from a rat fed 3-Me-DAB for 8 weeks. As described above, liver cells from rats fed 3-Me-DAB demonstrated much greater proliferative ability than normal control cells in vivo and in vitro.Abbreviations used HCC hepatocellular carcinoma - 3-Me-DAB 3-methyl-4-dimethylaminoazobenzene - GGT -glutamyltranspeptidase     

Chlamydia trachomatis serology in ankylosing spondylitis

Summary Demonstration of chlamydial antibodies in patients with ankylosing spondylitis (AS) could show an etiological roel of Chlamydia trachomatis in this condition. We studied serum specimens from 50 HLA-B27 positive patients with AS (Group I), 34 HLA-B27 positive patients with other rheumatic diseases (Group II), 67 HLA-B27 positive healthy blood donors (Group III) and 37 healthy untyped blood donors. (Group IV). Measured by an immunoperoxidase assay (IPA) chlamydial IgA (titre 120) was more prevalent in the HLA-B27 positive persons than in the healthy controls not selected for HLA-group (Groups I+II+III vs IV: p<0.02). Chlamydia trachomatis IgA-IPA containing sera also had specific IgG-IPA antibodies (180) in 29 (96%) out of 30 sera from HLA-B27 positive individuals and controls. Conversely, 45% of specific IgG-positive (180) AS sera, 27.7% sera in Group II, 39.4% Group III sera vs. 11.1% of sera in Group IV had concomitant chlamydial IgA (120). The differences in the prevalence of specific IgA were statistically significant: Group I vs. IV: p<0.01; Group III vs. IV: p<0.05 and Gr. I+II+III vs. IV: p<0.05. Our data suggest an enhanced antibody production against Chlamydia trachomatis among the HLA-B27 positive individuals whether they have AS or are healthy.     

Low Endogenous Prostaglandin E2 Predisposes to Relapsing Inflammation in Experimental Rat Enterocolitis

Intramural injection ofpeptidoglycan-polysaccharide (PG-PS) induces acuteenterocolitis that spontaneously relapses in Lewis butnot Fischer rats. Interleukin-1 (IL-1) and tumornecrosisfactor- (TNF-) induce prostaglandin E₂(PGE₂) secretion, which inhibits secretion ofthese cytokines by macrophages, suggesting an inhibitoryfeedback mechanism. We postulate that Lewis ratsusceptibility to relapse is due to an imbalance betweenprotective prostaglandins and cytokines. Female Fischerand Lewis rats were injected with PG-PS (37.5 g/g)or human serum albumin intramurally. Tissue IL-1 and PGE₂ immunoreactivities andmyeloperoxidase (MPO) activity were determined.Relapsing rats had lower PGE₂ andPGE₂:IL-1 ratios than nonrelapsingrats (P < 0.05). In Fischer rats, 2 mg/kg/day indomethacinpotentiated cecal MPO and IL-1 concentrationsabove PG-PS alone (P < 0.05). Misoprostol treatmentblocked PG-PS-induced IL-1 and MPO and inhibited the potentiating effect of indomethacin on MPOand IL-1 (P < 0.05). In conclusion, increasedendogenous PG may be protective against relapsinginflammation in PG-PS induced enterocolitis, at least partially via inhibition of proinflammatorycytokines. An imbalance between protectiveprostaglandins and proinflammatory cytokines may beinvolved in the pathogenesis of chronic relapsinginflammation in genetically susceptible hosts.