Genetic polymorphism of cytochrome P4502E1 in a Swedish population. Relationship to incidence of lung cancer

Genetic polymorphism of CYP2E1 was investigated among 195 Swedish patients with lung cancer and 206 controls. Three different polymorphic sites were found, all in introns, using RFLP and the restriction enzymes DraI, RsaI and TaqI. The frequencies of the rare alleles were 0.08-0.18 and much lower than previously described among Japanese. No significant difference in distribution of the polymorphic alleles between controls and lung cancer patients was evident, in contrast to results of a previous Japanese study. However, examination of a polymorphic site in the 5'-flanking region, within a putative binding motif for the hepatic transcription factor HNF-1, revealed a significantly less frequent distribution of the mutated allele (c2) among the lung cancer patients as compared to controls. It is concluded that major interethnic differences exist in the genetic polymorphism of CYP2E1 and that people carrying the c2 allele might be at lower risk for developing lung cancer.

Diet counselling and behaviour change

A number of questions related to oral as well as general health seem to be relevant to a discussion on development of counselling techniques aimed at changing various types of health-related behaviour in man, such as dietary habits, smoking, and alcohol use. This paper discusses dietary counselling and behaviour change in dental practice.

Genetic polymorphism of cytochromes P450: interethnic differences and relationship to incidence of lung cancer

The cytochromes P450 participate in the metabolic activation of precarcinogens. Recent results reveal that many P450 genes are polymorphically distributed. Different investigators have tried to link polymorphic variants of the CYP1A1, CYP2D6 and CYP2E1 genes to the incidence of cancer, particularly lung cancer, in Asian and Caucasian populations. In the current overview we briefly summarize this research. It appears that interesting functionally linked interindividual differences in the CYP1A1 gene have been found and could be of importance in understanding differences in susceptibility to lung cancer. On the other hand, the data presented regarding CYP2D6 and CYP2E1 are less promising. We also describe interethnic differences in the P450 gene structures as a major obstacle for extrapolation of results between different ethnic groups.

Salivary hypofunction in patients with familial amyloidotic polyneuropathy

Patients who suffer from familial amyloidotic polyneuropathy frequently complain of mouth dryness and an increased need for dental treatment. The aim of the present investigation was to study saliva secretion rate and composition and other factors related to the risk of dental caries in patients with familial amyloidotic polyneuropathy. Thirty patients with familial amyloidotic polyneuropathy volunteered for the study and were compared with a matched control group. Samples of unstimulated and stimulated whole saliva were collected in a standardized manner. The secretion rates were calculated, and the concentrations of electrolytes, glycoprotein markers, and proteins with antibacterial properties were analyzed. Dental caries and variables related to the risk of dental caries were also scored. The results show that familial amyloidotic polyneuropathy patients frequently have a decreased rate of saliva secretion and that the degree of salivary hypofunction is positively correlated to the progress of familial amyloidotic polyneuropathy. Forty-three percent of the familial amyloidotic polyneuropathy patients in this study had no detectable secretion of unstimulated saliva. A low secretion rate of stimulated saliva (< 0.7 ml/min) was found in 33% of the patients. The concentrations of salivary protein, amylase, lysozyme, salivary peroxidase, secretory IgA, hexosamines, sialic acid, fucose, phosphate, potassium, and the degree of protein glycosylation were higher in the familial amyloidotic polyneuropathy patients than in the control patients. We conclude that patients with familial amyloidotic polyneuropathy have a reduced saliva secretion and are subsequently at risk for increased development of dental caries.

Platelet-derived growth factor potentiates phorbol ester-induced neuronal differentiation of human neuroblastoma cells

Previous studies have shown that platelet-derived growth factor (PDGF) and PDGF receptors are expressed in the mammalian central nervous system and that primary cultured neuroblasts from rat hindbrain have functional PDGF beta-receptors. Here, it is shown that cultured human neuroblastoma cells express PDGF alpha- and beta-receptors, but not PDGF-A and PDGF-B chain mRNA. In contrast to alpha-receptor expression, beta-receptor expression appears to be associated with a mature neuronal phenotype. Under serum-free growth conditions, PDGF-AA and -BB induce a trophic and weak mitogenic response in SH-SY5Y neuroblastoma cells, showing that the PDGF receptors in these cells are functional. In combination with 12-O-tetradecanoylphorbol-13-acetate, all three PDGF isoforms induce sympathetic neuronal differentiation of the SH-SY5Y cells, as shown by morphology and by increased expression of the genes coding for growth-associated protein 43 and neuropeptide tyrosine, respectively. This indicates a potential role for PDGF in the development of sympathetic neurons in particular and of the nervous system in general.

CT showing early ventricular dilatation after subarachnoidal hemorrhage

We performed a retrospective analysis of 398 patients with subarachnoidal hemorrhage (SAH) confirmed by CT. On the first CT examination the temporal horns were enlarged in 84%, the frontal horns in 32%, and the third ventricle in 21% of the patients. The amount of blood in the basal cisterns was highly correlated to dilatation of the temporal horns. The temporal horns were enlarged even when small amounts of blood were found in the cisterns. The frontal and temporal horns were dilated only when moderate or large amounts of blood were present in the cisterns. In 24 patients no blood was seen in the basal cisterns on CT performed within 5 days of the hemorrhage; none of the 3 patients with aneurysms showed normal temporal horns while 18 without demonstrable aneurysms had normal, and 3 had moderately dilated, temporal horns. Because the temporal horns cannot usually be seen at CT of healthy individuals, dilatation could be a useful sign in the diagnosis of SAH.

Increased release of tissue plasminogen activator and its inhibitor in human parotid saliva upon stimulation

Parotid saliva from 12 healthy volunteers was collected prior to and after 5 and 25 min of stimulation at a constant flow rate of 0.25 or 1.0 ml min-1. In the salivary samples the concentrations of tPA (tissue-type plasminogen activator), PAI-1 (plasminogen activator inhibitor type-1), albumin and total protein were determined and the activity of amylase, tPA and PAI assessed. Presence of both tPA and PAI-1 antigen was demonstrated in all samples, and in unstimulated saliva the ratio between the activator and its inhibitor was 1:7. Upon stimulation we found a significantly increased concentration of PAI-1, a less pronounced increase in tPA concentration, unchanged amylase and total protein levels and significantly decreased albumin concentration. tPA activity was significantly reduced after prolonged stimulation which had no effect on PAI activity. In stimulated saliva a significant positive correlation between concentration of tPA and PAI-1 was demonstrated. Stimulation with citric acid had no effect on output of albumin which is passively filtered from blood, whereas the increase in flow rate corresponded to the significantly increased secretion rate of total protein and amylase which is secreted by gland cells. The secretion pattern of tPA and PAI-1 differed significantly from that of albumin in showing markedly increased output rate during the stimulation period, and the relative increase in output of PAI-1 was significantly higher than that of amylase and total protein. Thus, the results from this study suggest an active release of both tPA and its main inhibitor PAI-1 into saliva.

Effects of ultraviolet irradiation on natural killer cell function in systemic lupus erythematosus

In vitro irradiation with long wavelength ultraviolet light (UV-A), in clinically relevant dosages, of a natural killer cell line containing cell preparations from 17 control subjects reduced natural killer cell cytotoxicity with the cell line K562 as target. The spontaneous function of natural killer cells from 12 patients with systemic lupus erythematosus (SLE) correlated inversely with the one hour erythrocyte sedimentation rate, but not with glucocorticoid doses. After UV-A exposure, natural killer cells from patients with SLE exert either increased or decreased cytotoxicity, and the direction of change is inversely correlated with the spontaneous natural killer cell function.

Prevalence of caries in adolescents in relation to diet

The aim of the present study was to compare dietary habits between adolescents with high or low dental caries prevalence. All 15-yr-old adolescents living in a small community in Northern Sweden were studied in 1987, 1988, and 1989. The median values for energy and nutrient intake exceeded or were close to the recommendations (SNR89) given by the Swedish National Food Administration. The fiber intake did not reach the recommended daily amount even for the 90th percentile of the studied cohort. Nineteen percent of the adolescents had caries free teeth and 10% had nine or more decayed or filled surfaces. There was no difference in daily sucrose intake or average number of meals per day between these two groups. The group with nine or more decayed or filled surfaces had worse dietary habits, expressed as a higher fat intake, lower intake of complex carbohydrates, and lower density of iron (mg/MJ) than the group with no dental caries. Dietary counseling by dentists should be a valuable addition to other caries prophylactic measures taken by the dentists.

[Genotyping for drug metabolism capacity can give valuable clinical information]

There is pronounced individual variation in the human metabolism (eg, acetylation and hydroxylation) of drugs, in many cases due to genetic factors. The genetic basis of cytochrome P4502D6 gene defects has recently been elucidated, for instance. The cytochrome P4502D6 is absent from 7 percent of the Caucasian population, usually owing to the presence of either of two different mutations in the corresponding gene. PCR amplification of genomic DNA with allele-specific primers enables rapid prediction of the patient's drug metabolism capacity and the individualization of drug treatment with respect to dosage.

Effects of dietary fat composition on activities of the microsomal ethanol oxidizing system and ethanol-inducible cytochrome P450 (CYP2E1) in the liver of rats chronically fed ethanol

We studied the effects of dietary fat composition on the activities of the microsomal ethanol oxidizing system (MEOS), paranitrophenol hydroxylase (PH) activity and ethanol-inducible cytochrome P450 isozymes (CYP2E1 and CYP2B1) in the liver of rats to determine the role of this ethanol metabolizing pathway in the pathogenesis of alcoholic liver disease (ALD). Wistar male rats were pair-fed a liquid diet, containing either tallow (TF) or corn oil (CF) as the fat component, and ethanol or an isocaloric amount of dextrose, through an implanted intragastric cannula. Liver pathology of rats fed ethanol (CF-ALC) and CF diet showed severe fatty change whereas the rats fed TF-alcohol and the TF and CF controls did not. MEOS activity of the CF-ALC group was 8 times of that in the CF-CTL group (P less than 0.01). In TF-ALC rats, MEOS activity was increased to 2.6 times compared to that of TF-CTL (P less than 0.01). ApoCYP2E1 in CF-ALC and TF-ALC were 818 +/- 63 and 433 +/- 1- pmol/mg protein, respectively, and these values were significantly higher when compared with those of the pair-fed controls (P less than 0.005). In contrast, apoCYP2B1 was increased to an equal degree in both CF-ALC and TF-ALC. When PH-activity was measured, the level of activity on TF-ALC rats did not differ from that of CF-ALC rats. Thus, ethanol-induction of apoCYP2B1 (2x) and PH (6-8x) were the same for CF and TF (2x); but not for apoCYP2E1 (21 and 8x, respectively) and MEOS activity (8 and 2.6x, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Comprehensive medical examination of a group of patients with alleged adverse effects from dental amalgams

Mercury from dental amalgams does not seem to cause dose-related intoxications. However, animal studies have shown that high-dose exposure to mercury may support various types of immunologic reactions. Ten patients claiming that their symptoms were caused and aggravated by amalgam therapy were selected for a study of the effects of removal of one amalgam restoration followed by placing of a composite filling. Clinical symptoms and the result of laboratory tests were recorded. Six patients had contact allergies to metals, three of them to mercury ammonium chloride. The comparison of pre- and post-experimental test results showed significant reductions in p-IgE and dU-albumin and significant increases in p-C3d and dU-beta 2-microglobulin. There was no laboratory evidence of a direct toxic effect by mercury on the patients. The observed response by some of the studied factors to the low acute exposure to amalgam may imply that an activation of the immune system occurred.

Zonation of cytochrome P450 isozyme expression and induction in rat liver

The regional expression of six different cytochrome P450 (CYP) forms in rat liver under constitutive and induced conditions was compared using immunological techniques. Immunostaining of consecutive thin sections from control liver revealed that the same hepatocytes, forming a 6-8 cells thick layer surrounding the terminal hepatic venules, were stained for CYP2B1/2, CYP2E1 and CYP3A1. Staining of CYP2A1 extended further into the midzonal region, whereas all cells of the acinus stained for CYPEtOH2. These results were supported by Western blot analysis of cell lysates from the periportal or perivenous region obtained by zone-restricted digitonin treatment during in situ perfusion. The data suggest three distinct patterns of constitutive P450 expression: perivenous-restricted (CYP2B1/2, CYP2E1 and CYP3A1); perivenous-dominated (CYP2A1) and panacinar (CYPEtOH2). Chronic exposure to ethanol caused induction of CYP2E1 in the same cells already being constitutively expressed, whereas CYPEtOH2 was more induced in the periportal area. The relative induction of CYP2B1/2, CYP3A1 and CYPEtOH2 after treatment with phenobarbital was stronger in periportal hepatocytes, resulting in levelling out of the initial perivenous dominance of CYP2B1/2 and CYP3A1, whereas CYPEtOH2 became periportal-dominated. Acetone induced CYP2E1, CYP2C11 and CYP3A1 selectively in the perivenous area. These studies indicate that a particular P450 isozyme is generally induced in the same cells where it is constitutively expressed, and that this regional selectivity is independent of the kind of inducer. The data suggest that, during maturation, the hepatocytes acquire various phenotypes in the periportal and perivenous region, to respond differently to endogenous and exogenous signals in the control of P450 expression.

N-myc gene amplification in neuroblastoma: a clinical approach using ultrasound guided cutting needle biopsies collected at diagnosis

N-myc gene amplification was studied in a consecutive series of neuroblastomas and ganglioneuromas, representing all of such tumours diagnosed in Sweden over a 4-year period. Both frozen and formalin fixed specimens were used for Southern blot analysis. Thirty-seven of 46 neuroblastomas and 7 of 9 ganglioneuromas were analyzed. Seven neuroblastomas and none of the ganglioneuromas showed N-myc gene amplification. All children with amplified tumours, including three infants, had advanced disease at diagnosis and aggressive course of disease. However, follow-up time was short for the two cases still alive. The use of an ultrasound guided cutting needle biopsy technique for obtaining the required tissue at diagnosis was evaluated in some cases. This technique appeared to be safe and clinically useful since early prognostic information was obtained. Using an imprint from the needle biopsy, the representativity could be confirmed. Ultrasound guided cutting needle biopsies can thus be used routinely to obtain N-myc gene amplification data prior to initiation of therapy in neuroblastoma.

Analysis of the CYP2D6 gene in relation to debrisoquin and desipramine hydroxylation in a Swedish population

The molecular basis of polymorphic debrisoquin hydroxylation was studied in 223 Swedish white subjects, 187 extensive metabolizers and 36 poor metabolizers phenotyped with debrisoquin and desipramine. Restriction fragment length polymorphism (RFLP) analysis of the CYP2D6 gene revealed that 52% of unrelated poor metabolizers were homozygous for Xba I 29 kb fragment, and only 8% had two mutant alleles detected with RFLP. Allele-specific polymerase chain reaction (PCR)-based DNA amplification, however, revealed that all but one of the poor metabolizers had two mutant alleles of the CYP2D6A or CYP2D6B type or both. Extensive metabolizers who were heterozygous for wild-type and CYP2D6B genes had metabolic ratios for debrisoquin and desipramine that were higher than those of subjects who were homozygous for the wild-type gene. The 16 + 9 kb Xba I RFLP pattern was associated with the poor metabolizer phenotype and CYP2D6B mutations. Three extremely rapid metabolizers of debrisoquin had a 44 kb Xba I fragment that did not carry either CYP2D6A or CYP2D6B mutations. In conclusion, in the Swedish population studied, allele-specific PCR amplification allowed prediction of the debrisoquin hydroxylation phenotype with 99% accuracy.

Salivary flow and dental caries in Indian children suffering from chronic malnutrition

Chronic protein-energy malnutrition during the period of growth and development causes permanent disturbances of salivary gland function and tooth structure. Moderate protein-energy deficiency also causes impaired saliva secretion rate and composition in the adult rat. These impairments have been shown to coincide with an increased incidence of dental caries. In the present investigation we studied the effect of chronic malnutrition on saliva secretion rate and susceptibility to dental caries in Indian children. It was found that chronic malnutrition reduced the secretion rate of stimulated saliva, but not that of unstimulated saliva. The salivary buffer capacity was continuously decreased as the secretion rate decreased with the level of malnutrition in the Indian children. The malnourished children developed increased caries. Thus, it could be concluded that chronic malnutrition in growing children enhances the cariogenic potential stemming from fermentable carbohydrates.

Insulin-like growth factor I shifts from promoting cell division to potentiating maturation during neuronal differentiation

SH-SY5Y neuroblastoma cells undergo neuronal differentiation and their proliferation is inhibited when they are treated with phorbol 12-myristate 13-acetate (PMA). Insulin and insulin-like growth factor I (IGF-I) are mitogens for the nontreated SH-SY5Y cells, whereas the proliferative response to such factor stimulation is lost upon differentiation, in spite of the fact that the receptors for insulin and IGF-I remain expressed and functional in the differentiated cells. Here we show that the PMA-induced differentiation of SH-SY5Y cells grown in a serum-free medium is strongly potentiated by nanomolar concentrations of IGF-I, as judged by morphology and markers for neuronal differentiation--e.g., neuropeptide tyrosine and growth-associated protein 43. Also, insulin and IGF-II potentiated the phorbol ester-induced differentiation, although less efficiently than IGF-I. Using blocking anti-receptor antibodies, it could be shown that the differentiation induced by these factors, in combination with PMA, was primarily mediated through the IGF-I receptor.

Coffee drinking and blood cholesterol--effects of brewing method, food intake and life style

The strongest correlations between coffee consumption and serum cholesterol levels have been found in countries where people drink coffee brewed by mixing coffee grounds directly in boiling water (boiled coffee). In the present study of a population-based sample of 1625 middle-aged subjects (the Northern Sweden MONICA Study), approximately 50% of the participants were drinking boiled coffee, and 50% were drinking filtered coffee. Consumers of boiled coffee had significantly higher serum cholesterol levels than consumers of filtered coffee. Subjects who drank boiled coffee reported a higher intake of fat. A linear multiple regression analysis with serum cholesterol as the dependent variable confirmed that boiled coffee was an important independent determinant of cholesterol levels. We conclude that subjects who drink boiled coffee have higher serum cholesterol levels than those who drink filtered coffee, and that the most likely explanation for this finding lies in the type of brewing method.

Blood lipids and diet in Swedish adolescents living in Norsjö, an area with high incidence of cardiovascular diseases and diabetes

In Norsjö in Northern Sweden a cardiovascular intervention programme, for adults is presently tested. The aim of the present study was to investigate the presence of factors related to cardiovascular disease in all 15-year-old adolescents living in Norsjö in 1987 and 1988. The total cholesterol concentration in serum, as an average for the test period, was 4.2 mmol/l and 4.7 mmol/l for boys and girls, respectively. Fourteen per cent of the boys and 32% of the girls had a total cholesterol concentration exceeding 5 mmol/l. Twenty-seven per cent of the adolescents had high values for two or more variables related to risk of developing cardiovascular disease. The evaluation of the dietary registrations showed unsatisfactory values for fibre, P/S ratio and total fat. The dietary habits were better in the 15-year-olds in 1988 than in 1987 as judged by significantly higher average daily intake of fibre as well as a higher content of fibre per megajoule in the food.

Acetone-regulated synthesis and degradation of cytochrome P450E1 and cytochrome P4502B1 in rat liver [corrected]

The regulation of CYP2E1 and 2B1 was studied by following mRNA levels, catalytic activities and the subcellular distribution of the apoproteins in rat liver 0, 6, 12, 24, 48 and 96 h after a single intragastric dose of acetone. No changes were observed in hepatic CYP2E1 mRNA levels at any time after acetone treatment, whereas rapid rises were observed in the microsomal amount of CYP2E1 protein and CYP2E1-catalyzed 4-nitrophenol hydroxylase and carbon-tetrachloride-initiated lipid-peroxidation activities. However, CYP2E1-dependent catalytic activities declined much faster than the immunodetectable CYP2E1 protein, suggesting that this cytochrome P-450 is inactivated prior to degradation. Similar results were seen in primary hepatocyte cultures. By contrast, concomitant changes in levels of CYP2B1 and CYP2B1-dependent O-depentylation of pentoxyresorufin were observed in the same microsomal preparations. Investigation of the degradative mechanism of both CYP2E1 and CYP2B1 by immunoquantitation of the proteins in lysosomes and by immunohistochemistry indicated their degradation via an autophagic-lysosomal pathway. The data suggest that CYP2E1 is acutely inactivated in the endoplasmic reticulum and that degradation of this isozyme occurs, at least in part, by the lysosomal route. By contrast, CYP2B1 is principally controlled at the level of synthesis.

Genetic analysis of the interethnic difference between Chinese and Caucasians in the polymorphic metabolism of debrisoquine and codeine

The Far Eastern and Caucasian populations are strikingly different with respect to the debrisoquine/sparteine hydroxylation polymorphism. The number of poor metabolizers, as defined for Caucasians, is very low among Chinese and Japanese. We investigated the molecular basis for this difference by analysis of the CYP2D6 gene in 115 Chinese subjects, combined with phenotypic classification of codeine and debrisoquine metabolism. A correlation between the rates of metabolism of these two drugs and genotype, as analyzed by RFLP using XbaI, was observed among the Chinese. A high frequency (37%) of alleles indicative of gene insertions (reflected by XbaI 44kb fragments) was recorded in the Chinese, but was not associated with the poor metabolizer phenotype, as it is in Caucasians. PCR amplification of part of the CYP2D6 gene with mutation specific primers for CYP2D6A (29A) and CYP2D6B (29B) allelic variants revealed that the XbaI 44kb fragment in Chinese apparently contains a functional CYP2D6 gene, in contrast to the situation among Caucasians. The results provide a molecular explanation of the interethnic difference in the metabolism of drugs affected by the debrisoquine hydroxylation polymorphism.

Hormone controlled phosphorylation and degradation of CYP2B1 and CYP2E1 in isolated rat hepatocytes

Addition of adrenalin to primary rat hepatocytes caused a 3- and 2-fold increase in [32P]-incorporation into CYP2E1 and CYP2B1, respectively. Adrenalin also increased the rate of CYP2E1 degradation at similar concentrations as needed for phosphorylation of the protein (r = 0.93), but did not influence the degradation rate of CYP2B1. Ethanol (75 mM) completely protected from adrenalin dependent phosphorylation and degradation of CYP2E1, but did not influence CYP2B1 on these parameters. Examination of para-nitrophenol hydroxylase revealed that ethanol stabilized the catalytically active form of CYP2E1. Insulin treatment caused a stabilization of CYP2E1, but did not affect CYP2B1 degradation. It is concluded that degradation of CYP2E1 is the subject of hormonal control, whereas CYP2B1 decomposition is accomplished in a different and a less regulated manner.

Acute radiation effects on saliva composition in rats with different vitamin A levels in serum

Irradiation of the head and neck often causes loss of salivary gland function which may lead to severe oral discomfort. The effects of a single dose of 25 Gy given to rats with different serum levels of vitamin A were studied. The salivary secretion rate as well as concentrations of protein, hexosamine, amylase and electrolytes, and the activities of two antibacterial glycoproteins were measured. At an adequate level of vitamin A in the diet, irradiation significantly reduced whole saliva secretion rate, and decreased the concentration of salivary sodium, calcium and hexosamine as well as the activity of a glycoprotein agglutinating a serotype c strain of S. mutans. Peroxidase, amylase and potassium were not significantly affected. The reductions seen at an adequate level of vitamin A were not reduced by supplementation of excess dietary retinol. The damage caused by irradiation was enhanced by vitamin A deficiency as seen in the reduced protein and hexosamine concentrations.

Escherichia coli in patients with renal scarring: genotype and phenotype of Gal alpha 1-4Gal beta-, Forssman- and mannose-specific adhesins

The frequency of Escherichia coli with Gal alpha 1-4Gal beta-specific adhesins is reduced among children who develop renal scars. The adhesion-negative phenotype may be due to the absence of the pap DNA sequences which encode these adhesins or to a phase variation event induced by in vitro culture. In the present study the frequency of pap and pil homologous DNA was determined by dot blot analysis with probes specific for the respective sequence using E. coli strains from children with recurrent pyelonephritis with and without renal scarring. The frequency of pap was 79% in the strains isolated from the nonscarring group compared with 39% in the strains from the scarring group (P less than 0.001). The Gal alpha 1-4Gal beta phenotype was expressed by 89% of the pap-positive strains from the nonscarring group compared with 71% in the scarring group (P less than 0.05). In addition 13 of 77 of the pap-positive E. coli strains agglutinated sheep erythrocytes but not the Gal alpha 1-4Gal beta latex beads; a reaction attributed to reactivity with the Forssman glycolipid. DNA sequences homologous with pil were found in 95% of all strains and there was no significant difference between the nonscarring and the scarring groups. The low frequency of Gal alpha 1-4Gal beta specific strains in the scarring group was therefore due to the absence of pap-homologous DNA sequences and to a reduced rate of phenotypic expression among pap-positive scarring strains. There was no support for a relationship between type 1 fimbriae and renal scarring.

Transcriptional control of CYP2E1 in the perivenous liver region and during starvation

Previous data indicate that the CYP2E1 gene is transcriptionally activated after birth, but that the expression of ethanol-inducible CYP2E1 protein, hereafter, is regulated by post-transcriptional mechanisms. The constitutive expression of CYP2E1 protein is restricted to the perivenous region of the liver lobule. Here we present results from in situ hybridization and run off experiments indicating that this regioselectivity is caused by a higher rate of gene transcription in the perivenous hepatocytes. We also show that transcription of the CYP2E1 gene is activated by starvation, indicating that also this P450 gene is under transcriptional control under certain physiological conditions.

Expression of the neuronal form of pp60c-src in neuroblastoma in relation to clinical stage and prognosis

The expression of the protooncogene c-src has been studied in specimens of childhood tumors with special reference to neuroblastoma and other tumors of neuronal origin. For comparison c-src gene expression was studied in seven neuroblastoma and neuroepithelioma cell lines. The structurally distinct neuronal product of the gene, pp60c-srN, expressed during normal development in neuroblasts and neurons, was identified by immunoblotting technique together with the fibroblast form, pp60c-src. While pp60c-src was found in most tumors studied, the neuronal form was restricted to neuroblastomas (23 of 27) and retinoblastomas (3 of 3) and could not be detected in the other childhood tumors. A dominance of the neuronal form, pp60c-srcN, was exclusively found in the infant cases of neuroblastoma (9 of 12), estimated to have good prognosis. These results indicate that pp60c-srcN might be a diagnostic marker in primitive childhood tumors. When expressed in higher amounts than pp60c-src, pp60c-srcN may be a positive prognostic marker in neuroblastoma, especially useful in the evaluation of infants. In addition, lack of pp60c-srcN seems to be incompatible with low stage neuroblastoma.

Substrate-, hormone-, and cAMP-regulated cytochrome P450 degradation

The hepatic cytochrome P450 system, with numerous different P450 enzymes, is characterized by its inducibility by a variety of endogenous and exogenous compounds. Specific forms of P450, exhibiting distinct but partially overlapping substrate specificities, are increased in response to a given chemical. Consequently, the rate of elimination of the inducing compound is often enhanced and the system is in this respect adaptive to changes in the environment. Transcriptional activation mechanisms for the endo- or xenobiotically controlled P450 synthesis are well documented. Here we describe a mechanism for posttranslational ligand-dependent stabilization of ethanol-inducible P450IIE1 in hepatocyte cultures. Glucagon or 8-bromoadenosine 3',5'-cyclic monophosphate causes an enhanced rate of P450IIE1 degradation in the hepatocytes as well as phosphorylation on Ser-129, a reaction which denatures the protein under in vitro conditions. Substrates for the enzyme, such as ethanol and imidazole, protect the enzyme from phosphorylation and degradation in hepatocytes but do not influence phosphorylation or degradation of phenobarbital-inducible P450IIB1. Our proposed mechanism, which remains to be shown under in vivo conditions, describes the P450 molecules as receptors for the compounds in question and might provide a way by which endo- and xenobiotics regulate their own rate of metabolism.

Evaluation of different hybridization procedures for the detection of mycoplasma contamination in cell cultures

Cell culture samples were analysed for mycoplasma contaminations with two different DNA probes which have been described earlier. One probe (the H900 probe), derived from the 23S rRNA gene of Mycoplasma hyorhinis, cross-hybridized with virtually all mycoplasmas (including the acholeplasmas). The other probe (the T2 probe), derived from a protein gene of Acholeplasma laidlawii, cross-hybridized with most acholeplasmas. The two probes were compared in three different direct filter hybridization procedures without previous isolation of DNA or RNA. One of the procedures, developed in the present study, gave the highest sensitivity in DNA-RNA hybridization but also worked satisfactorily in DNA-DNA hybridization. The sensitivity of the H900 probe in filter hybridization experiments was compared with the sensitivity of a commercial probe for detection of mycoplasma contaminations in cell cultures. The H900 probe was found to be at least 25 times more sensitive for all cell culture mycoplasmas except for A. laidlawii, for which they were equally sensitive.

Central post-stroke pain--somatosensory evoked potentials in relation to location of the lesion and sensory signs

Somatosensory evoked potentials (SEPs) were studied in 27 patients with central post-stroke pain and in 19 controls. A scoring system for SEP was used, in which increasing abnormalities rendered increasing scores. SEPs evoked by electrical stimulation of the median and tibial nerves were compared to perception thresholds for touch, vibration, innocuous and noxious temperature. All patients had reduced temperature sensibility, while the threshold for touch and vibration was abnormal in only 52% and 41%, respectively. Decreased touch and vibration sensibility had a high correlation with high SEP scores, while no correlation was found between reduced temperature sensibility and SEP. The patients with thalamic lesions had the most severely affected SEPs, the ones with lower brain-stem lesions were the least affected. The results support the notion that the SEP is dependent on the lemniscal pathways and that lesions of the spinothalamic pathways are crucial for the development of CPS.

Prognosis in patients with transient ischaemic attacks and minor stroke associated with a normal angiogram

61 patients with a transient ischaemic attack (TIA) or minor stroke and a normal angiogram and with no other explanation for the ischaemic event were followed up for a mean period of 6.3 years. Of 19 patients with a TIA 5 suffered further TIAs, and 1 of the 5 also an ischaemic stroke. 3 of 42 patients with a minor stroke had a new ischaemic stroke, in 1 case preceded by a TIA. In 2 stroke patients the lesion affected a new arterial region. 3 patients died of cerebral haematoma, in 1 preceded by an ischaemic stroke. 4 patients suffered myocardial infarction, and 1 of these died. The overall incidence of recurrent cerebral and cardiovascular symptoms was 23% (14 of 61 patients). The mean age was significantly higher (p less than 0.01) in patients with recurrent cerebral and cardiovascular lesions. No correlation emerged between risk factors. Patients with a TIA or minor stroke and a normal angiogram and with no other known source of embolism have a better prognosis than patients with a known source of embolism. However, elderly patients in particular run an increased risk of cardiac and cerebral vascular incidents.

Effect of moderate protein-deficiency on ultrastructure in parotid and submandibular acinar cells in the adult rat

Powdered diets, of three different levels of protein, were given to groups of adult male rats for 21 days. Two diets with reduced protein content, 5% or 10% casein, were given to experimental rats. A diet with an adequate protein content, 20% casein, was given to controls. A reference group of rats was fed a standard pellet diet for the same period. At the end of the experimental period, the parotid and the submandibular glands were removed and subjected to electron microscopy. The zymogen granules of acinar cells in the parotid glands from the rats receiving the 5% protein diet had lost their normal opaqueness and turned electron lucid whereas parotid glands from the rats fed the 20%, the 10%, and the standard pellet diet exhibited normal acinar cells. The ultrastructure of submandibular acinar cells was not affected in any dietary group.

Effects of chronic stimulation of salivary gland beta-adrenoceptors on saliva composition and caries development in the rat

The effects of long-term beta-adrenoceptor stimulation or inhibition on parotid and submandibular glands, saliva secretion, and caries development were studied. Groups of rats were treated daily with: 0.5 or 5 mg/kg body weight of isoproterenol (IPR), 0.5 or 5 mg/kg bw propranolol (PRO), or saline. After 42 days, saliva was collected and analyzed for secretion rate, total protein, amylase, sialic acid and electrolytes. Total protein and amylase in saliva decreased and potassium increased in the high IPR group. Phosphate increased in both IPR groups and decreased in the high PRO group. The average weight of parotid glands increased 3.7 times in the high IPR group and 1.8 times in the low IPR group. Amylase and total protein in parotid gland extracts decreased in both IPR groups. The submandibular gland weight increased 1.5 times in the high IPR group. Total protein decreased in the high IPR group. There was no difference in caries development.

Effect of a moderate vitamin A deficiency on saliva secretion rate and some salivary glycoproteins in adult rat

The study presents the effect of a low vitamin A intake on saliva secretion rate and some salivary glycoproteins in the adult rat. Sixteen rats in the experimental group were fed a vitamin A deficient diet (0.11 micrograms retinol/g diet) and 14 rats in the control group a diet with adequate content of vitamin A (4.74 micrograms/g diet). At the end of the experimental period of 10 wk, whole saliva, blood, and liver samples were collected. No difference in the serum content of retinol was seen between the two groups. The liver values were significantly lower for the rats in the experimental group compared to the values in the control group. No difference was seen between the two groups in saliva secretion rate, salivary peroxidase activity, or the concentrations of total protein and markers for total glycoprotein secretion. However, the activity of a bacteria agglutinating glycoprotein, BAGP, was significantly reduced in the rats fed the vitamin A deficient diet.

Central post-stroke pain--a study of the mechanisms through analyses of the sensory abnormalities

The somatosensory abnormalities in 20 men and 7 women (mean age 67 years, range 53-81) with central post-stroke pain (CPSP) have been analysed in detail with traditional neurological tests and quantitative methods. The cerebrovascular lesions were located in the lower brain-stem in 8 patients, involved the thalamus in 9 and in 6 were suprathalamic. In 4 patients the location of the CVL could not be determined. All patients had abnormal temperature and pain sensibility, with a severe deficit in most cases. All except 2 had raised thresholds to thermal pain and all except 1 had abnormal sensibility to pin-prick. Eighty-eight percent exhibited hyperpathia with combined loss and suprathreshold exaggeration of somatic sensibility. In 85% somatic stimuli evoked dysaesthesia and about half of these patients also experienced spontaneous dysaesthesia. Paraesthesias were reported by 41%, radiation of stimuli by 50%, after-sensations by 45% and allodynia by 23%. Vibration sensibility was abnormal in 41%; raised thresholds to the perception of touch were found in 52%, to 2-PD in 35%, to dermolexia in 45% and to joint movements in 37%. The results indicate that all patients with CPSP have lesions that affect the major pathways for temperature and pain sensibility, i.e., the spino-thalamo-cortical pathways. Furthermore it appears that neither the level of the lesion along the neuraxis nor concomitant injury to the medial lemniscal pathways is crucial for the development of CPSP. The results confirm the notion that CPSP is a deafferentation syndrome, but they also provide evidence against the hypothesis that CPSP is a release phenomenon caused by a lesion that removes inhibitory influences of the lemniscal pathways on neurones that evoke pain.

Central post-stroke pain--neurological symptoms and pain characteristics

The intention of the present study was to characterize patients with central post-stroke pain (CPSP) with regard to type and location of the cerebrovascular lesion (CVL), the characteristics of the pain and the neurological symptoms and signs in addition to the pain. Twenty men and 7 women with a mean age of 67 years and a mean pain duration of 44 months were examined 9-188 (mean 53) months after their stroke. The clinical symptoms and signs and the CT scans indicated that the CVL were located in the lower brain-stem in 8 patients, involved the thalamus in 9 patients and were located lateral and superior to the thalamus in 6 patients. In the remaining 4 patients the location of the CVL could not be determined with certainty. The 3 identified hematomata were all located in the thalamus. The onset of the pain was immediate in 4 patients, within the first post-stroke months in 10 patients and delayed by 1-34 months in the rest. The pain was on the left side in 18 patients. Twenty patients had hemipain. Most patients experienced more than one type of pain. The most common qualities were burning, aching, pricking and lacerating, with some differences in the frequencies according to the location of the CVL. Burning pain was most common, except among the patients with thalamic CVL, in whom lacerating pain was more common. Aching and pricking pain were also frequent. All patients considered the pain to be a great burden and most rated the pain intensity as high on a visual analogue scale. The intensity was increased by external stimuli, the most common being joint movements, cold and light touch. Five patients reported aggravation by emotional stimuli. Besides pain, the only neurological symptom common to all patients was decreased temperature sensibility, as shown by quantitative methods. It is possible that pain sensibility was also abnormal in all. Hypersensitivities to cutaneous stimuli, including evoked dysesthesias were found in 88% of the patients, while the detection thresholds for touch and vibration were abnormal in only 52% and 41%, respectively. Similarly, low figures were found for paresis and ataxia, which were present in 48% and 62%, respectively. It is concluded that only a minority of patients with central pain after stroke have thalamic lesions.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of a 900-kcal liquid or solid diet on saliva flow rate and composition in female subjects

Eleven healthy females of normal weight participated in a study on the effects of two 900-kcal (5,548 kJ) diets, one solid and one liquid, given for 8-day periods. Unstimulated and stimulated whole saliva was collected before, during, between, and after the two different experimental periods. The dietary intake was recorded and evaluated for its content of energy and nutrients during normal and experimental periods. The 900-kcal liquid diet caused a reduction in saliva secretion rate, sialic acid, and phosphate concentrations and an increase in the sodium concentration as well as in the ratio of total protein to sialic acid. Chewing a 900-kcal solid diet restored saliva secretion and composition. The rate of dental plaque formation was increased by both 900-kcal diets, but more during the liquid period.

Centrilobular expression of ethanol-inducible cytochrome P-450 (IIE1) in rat liver

Western blot analysis of digitonin eluates as well as immunohistochemical analysis revealed a 30-fold higher concentration of cytochrome P-450IIE1 in the centrilobular than in the periportal regions of the rat liver. Ethanol treatment caused a selective centrilobular induction of P-450IIE1, whereas phenobarbital induced P-450IIB1/2 in both liver lobule regions. The heterogeneous distribution pattern of P-450IIE1 was also observed in cells isolated from either region and correlated to the relative content of P-450IIE1 mRNA in the two cell types. The regiospecific expression and induction of P-450IIE1 may explain why several hepatotoxins, known to be metabolized by this isozyme, primarily damage the centrilobular region in the liver.