Ecotoxicity and biodegradability of an alkyl ethoxysulphate surfactant in coastal waters

Alkyl ethoxysulphates (AES) are anionic surfactants widely used in numerous commercial and industrial applications. In spite of the high AES volume consumption a few data concerning the occurrence, fate and effects of AES in marine environments are reported in literature. The objective of this study is to evaluate the biodegradability and toxicity of AES in pristine sea water. Ultimate biodegradation was studied according to the guideline 835.3160 "Biodegradability in sea water" proposed by the United States Environmental Protection Agency (USEPA). Acute toxicity of AES was studied to the microalgae Nannochloropsis gaditana, Isochrysis galbana, Chaetoceros gracilis, Dunaliella salina and Tetraselmis chuii and the invertebrate Artemia franciscana, using culture growth inhibition and death, respectively, as effect criteria. During the degradative process two different stages were observed, which were better described with the first order and logistic kinetic models, respectively. Lag times were 3.3 (stage A) and 26.5 (stage B) days whereas half-lives were 18.6 (stage A) and 49.8 (stage B) days. AES inhibited the microalgae growth, with 96-h EC50 values ranging from 4.68 g L(-1) for D. salina to 24.02 mg L(-1) for I. galbana. Mean 48- and 72-h LC50 values for A. franciscana were 38.30 and 23.92 mg L(-1), respectively. The results indicate an extensive biodegradability of AES in sea water, although at a very slow rate. Acute toxicity was highly dependent on the species tested, being the green alga D. salina the most affected organism. The present study provides relevant data concerning the biodegradability and adverse effects of an AES surfactant on marine organisms, which are useful to establish water quality criteria in a regulatory framework.

Temporal bone dissection: a possible route for prion transmission?

The aim of this study was to determine whether neural tissue is present in the bone 'dust' given off during temporal bone drilling. Bone 'dust' from three temporal bone dissections was collected and examined. Evidence of neural tissue was present in two out of the three specimens. Neural tissue is present in the bone dust given off during temporal bone drilling. This poses the question as to the risk of prion transmission during such dissection.

Multiple basal cell carcinomas and malignant melanoma following radiotherapy for ankylosing spondylitis

We present the case of a 53-year-old Caucasian woman with seven basal cell carcinomas and one malignant melanoma in situ along her back overlying her spine, which was irradiated in 1968 for ankylosing spondylitis. These lesions developed between 1997 and 1999. She has no other known risk factors for cutaneous malignancy, in particular no history of excessive sun exposure. She has skin type 2. Molecular studies of glutathione S-transferase and cytochrome P450 status showed her genotype not to constitute an overall increased inherited susceptibility. We therefore postulate that all her skin cancers have arisen as a consequence of her radiotherapy. To our knowledge this is the first case of multiple basal cell carcinoma in addition to a malignant melanoma following radiotherapy for benign disease.

Probabilistic Inference from Arbitrary Uncertainty using Mixtures of Factorized Generalized Gaussians

This paper presents a general and efficient framework for probabilistic inference and learning from arbitrary uncertain information. It exploits the calculation properties of finite mixture models, conjugate families and factorization. Both the joint probability density of the variables and the likelihood function of the (objective or subjective) observation are approximated by a special mixture model, in such a way that any desired conditional distribution can be directly obtained without numerical integration. We have developed an extended version of the expectation maximization (EM) algorithm to estimate the parameters of mixture models from uncertain training examples (indirect observations). As a consequence, any piece of exact or uncertain information about both input and output values is consistently handled in the inference and learning stages. This ability, extremely useful in certain situations, is not found in most alternative methods. The proposed framework is formally justified from standard probabilistic principles and illustrative examples are provided in the fields of nonparametric pattern classification, nonlinear regression and pattern completion. Finally, experiments on a real application and comparative results over standard databases provide empirical evidence of the utility of the method in a wide range of applications.

Accuracy of staging in primary biliary cirrhosis

AIMS

To evaluate sampling variability of liver biopsy in patients with primary biliary cirrhosis (PBC).

METHODS

Sections from 50 PBC liver specimens obtained at transplantation were examined. The degree of fibrosis was assessed on a scale of 0-4 using two methods: (1) simulated needle biopsy in fields approximately the size of conventional needle biopsy; and (2) whole section scanning in areas with little and extensive fibrosis.

RESULTS

Considerable variation in the range of stages of fibrosis was found when the whole section scanning method was used. Only 10 (20%) samples had a consistent degree of fibrosis in all sections scanned. By contrast, the same fibrosis stage was assigned in 30 (60%) specimens examined using the simulated needle biopsy method. When the results obtained by the two methods were compared, there was a discrepancy of one or two stages in 32 samples. This discrepancy was the result of discovering areas with a lesser degree of fibrosis in whole sections compared with the simulated needle biopsy specimens.

CONCLUSION

There is considerable variation in the degree of fibrosis in the livers of patients with PBC, even when end stage specimens obtained at transplantation are examined. Consistent results were obtained when simulated needle biopsy specimens were examined. This, however, may be a reflection of the procedure applied when staging liver needle biopsy specimens, where the greatest degree of abnormality is used in determining the stage. The practice of staging of PBC in small needle biopsy specimens is valuable as long as the appearances are interpreted with caution, bearing in mind that there is considerable variability in the degree of fibrosis.

Superficial thrombophlebitis, dysplasia, and cholangiocarcinoma in primary sclerosing cholangitis

Cholangiocarcinoma occurs in approximately 10% of patients with primary sclerosing cholangitis. Usually, liver failure, rapidly progressing jaundice, and an increase in alkaline phosphatase levels are suggestive diagnostic features. We report two cases of patients with primary sclerosing cholangitis who developed cholangiocarcinoma without jaundice and with no changes in their serum biochemistry. Both patients were taking ursodeoxycholic acid at the time of tumor diagnosis. Initial suspicion of malignancy was based on the development of superficial thrombophlebitis. Liver histology showed evidence of bile duct epithelial dysplasia in areas free from tumor in one patient, and in the other, bile duct epithelial dysplasia preceded the appearance of cholangiocarcinoma by at least 18 months. In one of the cases, the dysplastic epithelium stained positively for carcinoembryonic antigen. The histological finding of bile duct epithelial dysplasia in patients with primary sclerosing cholangitis may suggest either imminent or actual development of cholangiocarcinoma and may thus affect consideration of orthotopic liver transplantation. In addition, the development of superficial thrombophlebitis in patients with primary sclerosing cholangitis should arouse suspicion of the presence of cholangiocarcinoma even if there is no evidence of deterioration of the liver function or a dominant stricture on endoscopic retrograde cholangiography.

Monoclonal antibody JC1: new reagent for studying cell proliferation

AIM

To characterise a newly developed mouse monoclonal antibody JC1 which recognises a nuclear antigen present in proliferating cells in normal tissues and neoplastic lesions, and which is absent in resting cells.

METHODS

The methodology was established using a representative range of frozen sections from normal tissues and from certain tumours which were immunostained with antibodies Ki67 and JC1. The molecular weight of the antigen recognised by JC1 was obtained by western blot analysis and this was compared with that of Ki67. IM-9 cell lysates containing Ki67 derived plasmids were also tested with JC1 antibody.

RESULTS

Biochemical investigation indicated that the antigen recognised by JC1 gives two molecular weight bands of 212 and 123 kilodaltons, which is distinct from the well characterised anti-proliferation monoclonal antibody Ki67 (395-345 kilodaltons). In addition recombinant Ki67 protein is not recognised by JC1. Immunohistological reactivity was seen in areas known to contain numerous proliferating cells such as lymphoid germinal centres, splenic white matter, cortical thymocytes and undifferentiated spermatogonia. In tumours many cells from adenocarcinomas, oat cell carcinomas, squamous cell carcinomas of lung, and seminomas were labelled by JC1 with a distribution and proportion similar to that seen with Ki67. In normal tissues the only apparent difference was in testis where JC1 stained a considerably greater number of cells than Ki67. In all cases studied the new antibody showed nuclear reactivity only. JC1 did not show any cytoplasmic crossreactivity with squamous cells as is frequently seen with Ki67.

CONCLUSION

Antibody JC1, which recognises a nuclear antigen present in proliferating cells, should provide a useful adjunct to Ki67 as a marker of proliferation especially in those cases such as squamous cell carcinomas where a Ki67 index cannot be determined.

Intracellular free magnesium in lymphocytes from patients with congestive cardiac failure treated with loop diuretics with and without amiloride

Cellular Mg2+ depletion has been reported in patients on long term diuretic therapy. We therefore measured lymphocyte free Mg2+ concentrations in patients with congestive cardiac failure treated with loop diuretics or a frusemide/amiloride mixture (Frumil) and compared them with control subjects. There was no correlation between lymphocyte free Mg2+ levels and plasma Mg2+ concentrations. Patients treated with loop diuretics did not show lymphocyte intracellular free Mg2+ depletion compared with normal controls, and those on Frumil showed higher intracellular free Mg2+ levels than normal.

Stimulation of the human leucocyte Na+/H+ antiport by D-glucose is mediated by protein kinase C

Leucocyte Na+/H+ antiport activity is elevated in patients with essential hypertension and Type 1 diabetes with nephropathy. To examine the effects of hyperglycemia on the Na+/H+ antiport, normal leucocytes were incubated with 25 mmol l-1 D-glucose, L-glucose or glucose-6-phosphate for two days. Leucocyte Na+/H+ antiport activity was measured by a novel double ionophore fluorimetric method for controlling intracellular pH. Only incubation with D-glucose led to an increase in Na+/H+ antiport activity of about 31%. This effect was not due to non-enzymic glycation since glucose-6-phosphate, which glycates proteins faster than D-glucose, caused no significant difference in antiport activity. Also, osmotic effects could be excluded. Staurosporine (10 nmol l-1), a specific inhibitor of protein kinase C, prevented the rise in antiport activity due to incubation with D-glucose. As hyperglycaemia is known to increase protein kinase C activity, elevation of this kinase may be one mechanism for activation of the Na+/H+ antiport in Type 1 diabetes.

Intracellular free magnesium in human lymphocytes and the response to lectins

1. Intracellular free [Mg2+] was measured in human peripheral blood lymphocytes using a fluorimetric method based on the dye furaptra. It was necessary to correct for the extracellular leakage of the dye by using either 10 mmol/l EDTA or 0.05 mmol/l Mn2+. 2. As the proliferative response of lymphocytes to mitogenic lectins has been linked to a dependence on extracellular Mg2+, the intracellular [Mg2+] was studied in lymphocytes stimulated with various mitogenic and non-mitogenic lectins. 3. Only lymphocytes treated with phytohaemagglutinin-L, a leucoagglutinin from Phaseolus vulgaris that binds to tri- and tetra-antennary complex glycoproteins, showed a marked increase in intracellular [Mg2+]. This effect was partially inhibited by N-acetylgalactosamine. The stimulation by different lectins of the incorporation of [3H]-thymidine into lymphocytes was not correlated to the changes in intracellular [Mg2+]. 4. The proliferative response of lymphocytes to lectins is therefore not wholly dependent on a rise in intracellular [Mg2+].

Leukocyte intracellular pH and Na/H antiporter activity in uraemia and type I diabetes mellitus

The leukocyte Na/H antiporter has been studied in patients with end-stage renal failure on maintenance haemodialysis. Thirteen non-diabetic haemodialysis patients (CRF group) and eight haemodialysis patients with diabetic nephropathy (CRF-DM group) were investigated. Measurements were made using the pH-sensitive fluorescent dye bis (carboxyethyl) carboxyfluorescein (BCECF). The initial intracellular pH (pHi), intracellular buffering capacity, and Na/H antiporter Vmax (at pHi = 6.0) have been recorded in bicarbonate-free solutions. The mean initial intracellular pH in the CRF group was 7.34 (SD 0.05, P less than 0.004) and this was significantly less than the CRF-DM group (7.42, SD 0.07) and normal controls (7.43, SD 0.09, n = 25). The mean intracellular buffering capacity was normal in the CRF and CRF-DM groups. The mean Na/H antiporter Vmax was also normal in the CRF and CRF-DM groups (56.5, SD 9.9; and 56.8, SD 12.8, mmol/l per min respectively compared to 55.2, SD 8.8, mmol/l per min in controls). These data are discussed with reference to the reported high values of Na/H antiporter Vmax in diabetic patients with early nephropathy. This abnormality does not appear to be present in end-stage diabetic nephropathy.

Leucocyte Na+/H+ antiport activity in type 1 (insulin-dependent) diabetic patients with nephropathy

The development of proteinuria in Type 1 (insulin-dependent) diabetic patients may depend on predisposition to essential hypertension in addition to poor glycaemic control. Previous work has shown increased leucocyte Na+/H+ antiport activity in essential hypertension and increased erythrocyte Li+/Na+ exchange in Type 1 diabetic patients with proteinuria. To test whether susceptibility to nephropathy in Type 1 diabetes was linked to abnormalities of leucocyte Na+/H+ antiport activity, we measured the intracellular pH and kinetics of the Na+/H+ antiport in 19 Type 1 diabetic subjects with, and 15 diabetic subjects without albuminuria and compared them to 25 matched normal control subjects. Intracellular pH (mean +/- SD 7.59 +/- 0.14) and maximal transport capacity of the antiport (Vmax 87.7 +/- 24.9 mmol.1-1.min-1) were higher in diabetic subjects with albuminuria compared to normotensive control subjects (pH 7.44 +/- 0.09; Vmax 55.6 +/- 10.3 mmol.l-1.min-1; p less than 0.001 for both), similar to the defect described in essential hypertension. These differences were not seen in diabetic subjects with normal urinary albumin/creatinine ratios (pH 7.46 +/- 0.09; Vmax 61.0 +/- 13.6 mmol.l-1.min-1). Buffering characteristics of the leucocytes at different pH in the Type 1 diabetic subjects with albuminuria differed from normal control subjects and diabetic subjects with normal urinary albumin/creatinine ratios. We conclude that increased leucocyte Na+/H+ antiport activity, a known marker of essential hypertension, is usually associated with nephropathy in Type 1 diabetes.

Effect of protein kinase C modulators on the leucocyte Na+/H+ antiport in type 1 (insulin-dependent) diabetic subjects with albuminuria

It is uncertain why only one third of Type 1 (insulin-dependent) diabetic patients develop nephropathy. One suggestion is the inheritance of a predisposition to essential hypertension. We have previously found elevated Na+/H+ antiport activity and a raised intracellular pH in leucocytes from hypertensive and Type 1 diabetic subjects with albuminuria using a novel double ionophore fluorimetric technique. These changes are not found in Type 1 diabetic subjects without albuminuria. We wished to test the effect of a protein kinase C inhibitor staurosporine (100 nmol/l) on the elevated antiport activity, and the degree of stimulation achieved by exogenous diacyl glycerol. Raised leucocyte Na+/H+ antiport activity of Type 1 diabetic subjects with albuminuria (73.8 +/- 17.2 mmol.l-1.min-1) was restored to normal levels with staurosporine (54.9 +/- 17.9 mmol.l-1.min-1, p less than 0.001). The leucocyte Na+/H+ antiport activity of diabetic subjects without albuminuria fell significantly also with staurosporine but to a lesser extent (57.3 +/- 11.6 to 50.0 +/- 12.8 mmol/l, p less than 0.003). In contrast, leucocytes from normal control subjects showed no change in antiport activity with staurosporine (54.3 +/- 8.5 to 52.6 +/- 10.4 mmol.l-1.min-1). Dioctanoyl glycerol stimulated the leucocyte Na+/H+ antiport in normal subjects and diabetic patients without albuminuria, with significantly less stimulation in diabetic patients with albuminuria. We conclude that reversal by staurosporine of the elevated Na+/H+ antiport activity in Type 1 diabetic subjects with albuminuria could indicate a role for protein kinase C in activating the antiport. This hypothesis is supported by the reduced stimulation of the antiport by dioctanoyl glycerol in this group of patients.

The export of the DNA replication inhibitor Microcin B17 provides immunity for the host cell

Microcin B17 (MccB17) is a peptide antibiotic which inhibits DNA replication in Enterobacteriaceae. Microcin-producing strains are immune to the action of the microcin. Physical and genetic studies showed that immunity is mediated by three genes: mcbE, mcbF and mcbG. We sequenced these genes and identified polypeptide products for mcbF and mcbG. By studying the contribution of each gene to the expression of immunity we found that immunity is determined by two different mechanisms. One of these, encoded by mcbE and mcbF, is also involved in the production of extracellular MccB17. To reconcile these observations we propose that McbE and McbF serve as a 'pump' for the export of active MccB17 from the cytoplasm. This model is supported by the predicted properties of the McbE and McbF proteins, which are thought to be, respectively, an integral membrane protein and an ATP-binding protein with homology to other transport proteins.

Hemodynamic effects of vanadate administration in rats with different levels of sodium intake

The acute hemodynamic effect of an intravenous (IV) bolus of vanadate (10 mumol/kg bwt) followed by an IV infusion at 0.5 mumol/kg min was studied in Wistar rats at three different levels of Na intake: low Na+ (0.5 mEq/24 h), normal Na+ (1.5 mEq/24 h), and high Na+ (15 mEq/24 h). Hemodynamic changes were measured using the radioactive microsphere method. Vanadate decreased cardiac output by 52.0 +/- 6.4% in low Na+ rats, by 41.2 +/- 3.3% in normal Na+, and by 29.2 +/- 3.1% in high Na+ group. Total peripheral resistances increased by 47.1 +/- 26% in high Na+ rats, by 80.1 +/- 6.6% in normal Na+, and by 96.3 +/- 4.5% in low Na+ group. Renal blood flow decreased by 70 +/- 4% in low Na+, 58 +/- 3% in normal Na+, and 39 +/- 3% in high Na+. Cerebral, testicular, and splanchnic blood flow showed smaller changes. These results demonstrate that intravenous vanadate induces marked hemodynamic changes that depend on Na+ intake being more striking when the intake of sodium is reduced.

The transposon Tn5 carries a bleomycin-resistance determinant

Transposon Tn5 carries a determinant for resistance to bleomycin (Bm). Deletion mapping and cloning experiments have shown that this determinant, gene ble, is located between the determinant for kanamycin (Km) and neomycin resistance (gene neo) and the determinant for streptomycin resistance (gene str). Genes neo, ble, and str belong to an operon controlled by the common promoter. The Mr of the ble product, as determined by polyacrylamide gel electrophoresis, is 12000 to 13000.

Splanchnic and systemic hemodynamic alterations in chronic, progressive portal hypertensive rats

Systemic and splanchnic hemodynamics were studied by using the radioactive microsphere technique, in rats in which a chronic and progressive portal or intrahepatic hypertension was produced by the placement of a nonconstricting, well fitted ligature around the portal or suprahepatic vein when the rat weighted about 100 g. The hemodynamic measurements were performed 80-90 days after ligature placement. Suprahepatic ligated rats presented portal and intrahepatic hypertension, but nonportal-systemic shunts (PSS). The only hemodynamic disturbance observed was a decrease in renal blood flow. Portal ligated rats showed a wide range of PSS and were divided in two subgroups. The subgroups with high PSS rate (greater than 10%) showed increased cardiac output and plasma renin content, as well as decreased splanchnic blood flow, portal venous inflow, hepatic blood flow and renal blood flow. Low portal-systemic shunts subgroups showed decreased cardiac output while its distribution was similar to the control rats. There was no correlation between portal pressure and shunt rate. Low shunt groups, furthermore, showed increased levels of plasma renin concentration.