Computer-assisted diagnosis for precancerous lesions in the esophagus.

OBJECTIVES: The interpretation of endoscopic findings by gastroenterologists is still a difficult and highly subjective task. Despite important developments such as chromo-endoscopy, pit pattern analysis, fluorescence imaging as well as narrow band imaging it still requires lots of experience and training with a certain tentativeness until the final biopsy. By the development of computer-assisted diagnosis (CAD) systems this process can be supported. METHODS: This paper presents a new approach to CAD for precancerous lesions in the esophagus based on color-texture analysis in a content-based image retrieval (CBIR) framework. The novelty of our approach lies in the combination of newly developed color-texture features with the interactive feedback loop provided by a relevance feedback algorithm. This allows the expert to steer the query and is still robust against accidental false decisions. RESULTS: We reached an inter-rater reliability of kappa = 0.71 on a database of 390 endoscopic images. The retrieval accuracy didn't change significantly until a wrong decision rate of 20%. CONCLUSIONS: Thus, the system could be able to support practitioners with less experience or in private practice. In combination with a connected case database it can also support case-based reasoning for the diagnostic decision process.

UGT1A7 polymorphisms in chronic pancreatitis: an example of genotyping pitfalls.

UDP-glucuronosyltransferases (UGT) catalyze the glucuronidation of various compounds and thus inactivate toxic substrates. Genetic variations reducing the activity of UGT1A7 have been associated with various gastrointestinal cancers. Most recently, the UGT1A7*3 allele has been reported as a significant risk factor for pancreatic disorders, but we could not confirm these data. This study focused on the possible causes for the noted discrepancy. UGT1A7 genotypes were assessed in 37 samples, which were previously analyzed for UGT1A7 polymorphisms by others. We determined genotypes by melting curve analysis and by DNA sequencing. Additionally, we produced UGT1A7*1 and *3 constructs with or without a mutation at position - 57 of UGT1A7 and analyzed various combinations of these constructs. In 14/37 samples UGT1A7 genotyping results differed. The discrepancy could be explained by polymerase chain reaction bias owing to an unbalanced allelic amplification which was caused by a -57T>G variant located within the sequence of the chosen primer template in previous studies. Our findings indicate that most of the previously reported genetic associations between UGT1A7 and gastrointestinal cancers are based on primer-dependent genotyping errors.

Polymorphisms of UDP-glucuronosyltransferase 1A7 are not involved in pancreatic diseases.

BACKGROUND: Xenobiotic mediated cellular injury is thought to play a major role in the pathogenesis of pancreatic diseases. Genetic variations that reduce the expression or activity of detoxifying phase II biotransformation enzymes such as the UDP-glucuronosyltransferases might be important in this respect. Recently, a UGT1A7 low detoxification activity allele, UGT1A7*3, has been linked to pancreatic cancer and alcoholic chronic pancreatitis. OBJECTIVE: To investigate whether UGT1A7 polymorphisms contribute to the risk of pancreatitis and pancreatic cancer. METHODS: Genetic polymorphisms in the UGT1A7 gene were assessed in a large cohort of patients with different types of pancreatitis and pancreatic cancer originating from the Czech Republic (n = 93), Germany (n = 638), Netherlands (n = 136), and Switzerland (n = 106), and in healthy (n = 1409) and alcoholic (n = 123) controls from the same populations. Polymorphisms were determined by melting curve analysis using fluorescence resonance energy transfer probes. In addition, 229 Dutch subjects were analysed by restriction fragment length polymorphism. RESULTS: The frequencies of UGT1A7 genotypes did not differ between patients with acute or chronic pancreatitis or pancreatic adenocarcinoma and alcoholic and healthy controls. CONCLUSIONS: The data suggest that, in contrast to earlier studies, UGT1A7 polymorphisms do not predispose patients to the development of pancreatic cancer and pancreatitis.

Autologous epidermal cells can induce wound closure of neurotrophic ulceration caused by trigeminal trophic syndrome.

Trigeminal trophic syndrome is an extremely rare complication following surgical ablation of the trigeminal nerve or after alcohol injection or thermocoagulation of the Gasserian ganglion. These lesions show a poor healing tendency and sometimes persist for years. The therapeutic results of local wound care with ointments and wound dressings are often unsatisfactory, and those of plastic surgery are variable. In the case presented, the skin area affected by neurotrophic ulceration is successfully treated with autologous cultivated epidermal cells. This form of tissue engineering is already a clinically established procedure for treating burns and chronic wounds. The results show for the first time that transplantation of in vitro cultivated epidermal cells can induce tissue regeneration and may be an effective tool in the treatment of neurotrophic ulcerations in the facial region.

Levels of parotid and submandibular/sublingual salivary immunoglobulin A in response to experimental gingivitis in humans.

Salivary secretory IgA (s-IgA) is considered to act as an important first line of defense mechanism in the oral cavity. It has therefore been suggested that an increased antigenic load would induce an increase in salivary IgA production. This study investigated the pure glandular levels of salivary IgA in parotid and submandibular/sublingual (SM/SL) saliva during plaque accumulation leading to experimental gingivitis. Starting from regular oral hygiene, 14 healthy, nonsmoking men refrained from all oral hygiene measures for 12 days. On days -2, 0, 3, 6, and 12 a plaque index, a bleeding index, and unstimulated and stimulated saliva from the parotid and the SM/SL glands were measured. Salivary IgA was quantified using a sandwich ELISA. All subjects developed gingivitis as measured by a bleeding index. Compared to baseline the salivary flow rate was increased on day 12. Regarding the secretion rate of IgA there was a statistically significant increase in stimulated parotid saliva but not SM/SL saliva compared to baseline after 6 and 12 days without oral hygiene. No significant changes were observed for the concentration of IgA during the trial. Thus, in healthy subjects with regular oral hygiene the development of plaque induced gingivitis is associated with increased salivary gland output and increased total IgA output levels in stimulated parotid saliva but not in SM/SL saliva.

Calibration of the viscometric glucose sensor before its use in physiological liquids--compensation for the colloid-osmotic effect.

The function of the recently described viscometric affinity sensor (VAS), which measures glucose due to its strong effect on the viscosity of a sensitive liquid containing Concanavalin A (ConA) and dextran, was analysed for osmotic and colloid-osmotic effects on the glucose reading. The suction of low- and high-molecular weight osmotica on the membrane of the microdialysis fibre was measured using a membrane osmometer built from the microdialysis probe of the VAS. The reduction of the sensor read-out in blood plasma can be completely explained by a change in small osmotic volume fluxes through the dialysis membrane, which affect the ConA concentration and the viscosity after the flow of the sensitive liquid through the dialysis probe. The measuring error could be prevented by the presence of the polyethylene glycol 6000 at an isotonic concentration in the glucose standard solutions used for sensor calibration.

Salivary IgA subclasses and bacteria-reactive IgA in patients with aggressive periodontitis.

The local salivary immunoglobulin A (IgA) response in patients with aggressive periodontitis to oral microorganisms and its role for the pathogenesis has not been determined. This study investigated the hypothesis that aggressive periodontitis patients have impaired oral secretory immunity. Our test group was made-up of 19 aggressive periodontitis patients and 19 age- and gender-matched periodontally healthy controls. Total IgA, IgA subclass 1, IgA subclass 2 and IgA reactive to Actinobacillus actinomycetemcomitans Y4, Treponema denticola ATCC 35404 and Candida albicans DSM 3454 were determined by enzyme-linked immunosorbent assay in whole unstimulated and stimulated saliva. A statistically significantly lower concentration and secretion rate of total salivary IgA (P < 0.01) and IgA1 (P < 0.001) was found in the aggressive periodontitis group in resting and stimulated saliva. A decrease of IgA2 (P < 0.05) was seen in resting saliva. Although only minor differences were detected in the concentration and secretion of bacteria-reactive IgA in both groups, the proportion of bacteria-reactive IgA from the total IgA was significantly higher (P < 0.01) in the aggressive periodontitis group in all three microorganisms tested. Our results indicate an inhibition of total secretory IgA. In particular an IgA subclass 1-specific decrease in aggressive periodontitis was noted, while the bacteria-reactive humoral immune system in saliva was activated. The role of the decrease of IgA1 immunoglobulins in aggressive periodontitis with respect to susceptibility for periodontal diseases has to be elucidated.

Alpha1-antitrypsin genotypes in patients with chronic pancreatitis.

BACKGROUND: An association between alpha1-antitrypsin deficiency and chronic pancreatitis (CP) has been reported in several case reports and two systematic studies. However, conflicting results have been shown in other studies of patients with CP. All previous studies were performed by phenotyping or by measurement of serum concentrations of alpha1-antitrypsin. The aim of this study was to investigate the relationship between alpha1-antitrypsin deficiency and CP by genetic analysis. METHODS: Ninety-six unrelated children and adolescents with idiopathic or hereditary CP and 185 healthy controls were enrolled. DNA was extracted from peripheral blood leukocytes and the exons 5 and 7 of the alpha1-antitrypsin gene were amplified by polymerase chain reaction using mutagenic forward primers introducing a Taq I restriction site. Genotyping of the S allele and the Z allele was performed by restriction fragment length polymorphism analysis using Taq I. RESULTS: Seven out of 96 patients (7.3%) with CP were heterozygous for an alpha1-antitrypsin deficiency allele (4 for the S allele and 3 for the Z allele). No patient was homozygous or compound heterozygous for these alleles. Twenty out of 185 control individuals (10.8%) were heterozygous for the S or Z allele (PiS: 12 controls; PiZ: 8 controls). No significant differences were found between the allele frequency in patients and the control individuals (P > 0.1). CONCLUSIONS: Alpha1-antitrypsin deficiency is not related to the pathogenesis of idiopathic or hereditary CP.

Differences in the salivary glycan pattern between children with high and low caries susceptibility.

Interactions between bacterial adhesins of lectin type and the oligosaccharide part of immobilised glycoconjugates on the tooth surface are involved in the specific colonisation of teeth. The specificity of the adhesion process is determined by the carbohydrate specificity of the bacterial lectins and the availability of the corresponding glycosylation pattern. On the other hand the same carbohydrate structures can specifically prevent the binding of bacteria by competitively blocking their adhesion, if sufficient amounts of this distinct carbohydrate structure are available in the secretion. Since carbohydrate binding receptors are also involved in the colonisation of tooth surfaces by cariogenic bacteria, it has been suggested that the architecture of the oligosaccharide portion of soluble glycoconjugates in saliva may play an important role as a constitutional host defence factor in the aetiology of dental caries. Characterising the availability of distinct carbohydrate patterns in saliva by using a pattern of well-described lectins in a competitive lectin inhibition assay we show that in children of a population-based sample a high caries susceptibility is associated with a reduced binding inhibition against the lectin peanut agglutinin (PNA). PNA is specific for the presence of terminal galactosyl residues and binds to the same O-glycan fractions as a surface lectin from Streptococcus mutans. The data suggest that a reduced availability of glycosylation patterns of galactosyl residues detected by the lectin PNA may act as an additional host-derived factor for an increased caries susceptibility.

Oral isobutyramide reduces transfusion requirements in some patients with homozygous beta-thalassemia.

The butyrate derivative isobutyramide (IBT) increases fetal hemoglobin (HbF) in patients with beta-hemoglobinopathies, but little is known about its usefulness for prolonged therapeutic use. We treated 8 patients with transfusion-dependent beta-thalassemia with 350 mg/kg of body weight per day of oral IBT for 126 to 384 days. During the trial period, the hemoglobin level was maintained between 85 g/L (range 82-87 g/L) (pretransfusion) and 115 g/L (range 110-119 g/L) (post-transfusion) (median, interquartile range), corresponding to 4-week transfusion intervals in all patients during the pretreatment phase. Adverse effects (bitter taste, epigastric discomfort) did not cause discontinuation of IBT. HbF increased in all patients from 3.1% (range 1.9%-4.8%) to 6.0% (range 3.3%-8.7) (P =.0017), while free Hb dropped from 0.48 g/L (range 0.39-0.81 g/L) to 0.19 g/L (range 0.16-0.24 g/L) (P <.0001). Transfusion intervals were consistently extended to 8 or 9 weeks in 1 patient, resulting in a decrease of daily iron load from 455 microgram/kg per day (range 451-459 microgram/kg per day) before therapy to 211 microgram/kg per day (range 203-286 microgram/kg per day) during the 12-month treatment period. Prolongation of transfusion intervals achieved by IBT was less consistent in another patient, whose parenteral iron load nevertheless decreased from 683 microgram/kg per day (range 618-748 microgram/kg per day) to 542 microgram/kg per day (340-596 microgram/kg per day). In the other 6 patients, no prolongation of transfusion intervals was achieved. Response to treatment was associated with high pretreatment HbF (> 4.5%), high parental HbF, and increased erythropoietin levels (> 150 IU/L). We conclude that IBT prolongs transfusion intervals and reduces parenteral iron burden in some patients with transfusion-dependent beta-thalassemia.

Mutations in the gene encoding the serine protease inhibitor, Kazal type 1 are associated with chronic pancreatitis.

Chronic pancreatitis (CP) is a continuing or relapsing inflammatory disease of the pancreas. In approximately one-third of all cases, no aetiological factor can be found, and these patients are classified as having idiopathic disease. Pathophysiologically, autodigestion and inflammation may be caused by either increased proteolytic activity or decreased protease inhibition. Several studies have demonstrated mutations in the cationic trypsinogen gene (PRSS1) in patients with hereditary or idiopathic CP. It is thought that these mutations result in increased trypsin activity within the pancreatic parenchyma. Most patients with idiopathic or hereditary CP, however, do not have mutations in PRSS1 (ref. 4). Here we analysed 96 unrelated children and adolescents with CP for mutations in the gene encoding the serine protease inhibitor, Kazal type 1 (SPINK1), a pancreatic trypsin inhibitor. We found mutations in 23% of the patients. In 18 patients, 6 of whom were homozygous, we detected a missense mutation of codon 34 (N34S). We also found four other sequence variants. Our results indicate that mutations in SPINK1 are associated with chronic pancreatitis.

Total IgA and Porphyromonas gingivalis-reactive IgA in the saliva of patients with generalised early-onset periodontitis.

Generalised early-onset periodontitis (GEOP) is characterized by acute inflammatory bursts, resulting in rapid destruction of the periodontal apparatus in young adults. An impaired host defense seems to play an important role as etiological factor of periodontitis, especially in the development of GEOP. As the gram-negative Porphyromonas gingivalis has been identified as one of the causative anaerobic bacteria, the humoral immune response to this micro-organism is of particular interest in patients with GEOP. To evaluate the local immune status, we measured total and P. gingivalis-reactive salivary IgA in GEOP patients and in age- and gender-matched periodontally normal controls. We found a significantly lower concentration and secretion rate of total salivary IgA in the GEOP group. Although no differences were detected in the concentration or secretion of P. gingivalis-reactive IgA between groups, the specific fraction of P. gingivalis-reactive IgA of the total IgA was significantly higher in the GEOP group. These findings indicate an inhibition of total secretory IgA in GEOP, while the P. gingivalis-reactive humoral immune system in saliva is, however, activated. P. gingivalis seems to selectively activate IgA lymphocyte clones and induces a switch in the fraction of specific IgA.

Suppression of interleukin-10 release from human periodontal ligament cells by interleukin-1beta in vitro.

Periodontitis is characterized by an inflammatory process induced by periodontopathogenic bacteria in the subgingival plaque. Periodontal inflammation can be enhanced by both an increase of inflammatory stimulators, e.g. interleukin (IL)-6, and a decrease of inflammatory inhibitors, e.g. IL-10. The amount of IL-1beta is known to be increased in gingival tissues and in the gingival crevicular fluid from inflamed sites compared to healthy sites. This in vitro study sought to clarity whether IL-1beta (1 ng/ml) has a regulatory effect on the release of these two cytokines from human periodontal ligament (PDL) cells. PDL cells derived from healthy premolars were grown in the presence and absence (control) of IL-1beta. The concentration of IL-6 and IL-10 in the supernatants was assessed by enzyme-linked immunosorbent assay after 48 h of culture. PDL cells incubated with IL-1beta released significantly (p < 0.05) higher amounts of IL-6 and significantly (p < 0.01) smaller amounts of IL-10 compared to control. These results give further support to the observation that IL-1beta can increase the IL-6 secretion from PDL cells. Moreover, they provide original evidence that PDL cells secrete IL-10, which can be suppressed by IL-1beta. It is concluded that PDL cells can function as accessory immunoinflammatory cells amplifying the inflammatory process in periodontitis and, thereby, contributing to periodontal breakdown.

Retinal pigment epithelial cells from Royal College of Surgeons dystrophic rats can take up melanin granules.

BACKGROUND: Many successful pigment epithelium transplantation studies involving pink-eyed Royal College of Surgeons (RCS) dystrophic rats showed highly pigmented transplanted cells forming a double layer with slightly pigmented cells, attached to Bruch's membrane. Since it is not clear whether transplanted pigmented cells can displace retinal pigment epithelial (RPE) host cells from Bruch's membrane, we suggested that RPE cells of RCS dystrophic rats can phagocytize melanin granules, possibly derived from perished transplanted cells. METHODS: In a series of three experiments, RPE cells of nine pink-eyed, 2 1/2-month-old RCS dystrophic rats were isolated by trypsinization and mechanical dissection and cultivated in Dulbecco's modified Eagles' medium. These cells were then fed with melanin granules, isolated from bovine RPE cells, double-trypsinized after phagocytosis and viewed by light and electron microscopy. We also transplanted iris pigment epithelial (IPE) cells of 20-day-old Long-Evans rats into the subretinal space of pink-eyed RCS dystrophic rats of the same age, shown in light-microscopic photography after 42 days. RESULTS: Living RPE cells were heavily pigmented after feeding with isolated melanin granules in all three experiments as viewed by light microscopy. In addition, we identified melanin granules phagocytized by dystrophic RPE cells in electron microscopy. After transplantation of pigmented IPE cells into the subretinal space of pink-eyed RCS dystrophic rats' eyes, a layer of slightly pigmented cells was seen on Bruch's membrane below the transplanted IPE cells, shown in light microscopy. CONCLUSION: We have shown by phagocytosis assay that dystrophic RPE cells can take up melanin granules in vitro. Our results assume that pigmented cells in transplantation studies, found as a monolayer, attached to Bruch's membrane, cannot automatically be identified as transplanted cells. Instead, the possibility of perished transplanted cells serving as melanin donors for RPE host cells must be taken into consideration.

Age and dementia effect on neuropsychological test performance in very old age--influence of risk factors for dementia.

In old age a large part of the variance in cognitive performance in population samples is explained by normal aging; in addition many subjects over 80 years are demented and therefore dementia also explains a part of cognitive variability. The question is whether the different factors for dementia (such as ApoE4, external atrophy parameter of the cranial computer tomography [cCT], education, sex or serum zinc level) influence the relation between age or dementia and Mini Mental State (MMSE) performance. In an epidemiological study data were analyzed of N = 239 subjects for the above factors. Most statistically significant variables of the MMSE do not change the amount of the partial correlation coefficient between the parameters age or dementia and MMSE. The external atrophy, however, diminishes the magnitude of the partial correlation between age and MMSE. In contrast the dementia-MMSE relation is unchanged. This points to a generally similar factor structure of cognitive aging and dementia in old age, but differences exist with respect to the importance of the external atrophy parameter of the brain. Most factors investigated explain separate parts of variance of cognitive performance in old age.

Local metronidazole application in maintenance patients. Clinical and microbiological evaluation.

The purpose of this investigation was to evaluate the clinical and microbiological effect of local antibiotic therapy in comparison with subgingival scaling and root planing in a randomized semi-masked study. Forty-six recall patients who completed systematic periodontal therapy 6 to 24 months prior to the study were enrolled. The inclusion requirements were at least one site with probing depth > or = 5 mm in each quadrant, no scaling, and no antibiotic therapy during the last 6 months. After randomization each patient received 2 different treatments: in 2 quadrants metronidazole 25% dental gel was applied subgingivally to the pockets at day 0 and day 7; scaling and root planing was carried out in the 2 other quadrants, one at day 0 and in the remaining quadrant at day 7. Subgingival microbiological samples were taken from each patient before treatment and on days 21, 91, and 175 after the treatment. The analyses were carried out by indirect immunofluorescence assay. At all treated sites probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) were recorded on days 0, 21, 91, and 175. Both treatments resulted in PD reduction and CAL gain. PD reduction was statistically significant (P < 0.01) for both treatment modalities after 6 months. The CAL gain was not significant for either treatment. There was no statistical significance between scaling and antibiotic therapy. Treponema denticola, Porphyromonas gingivalis, and Prevotella intermedia were significantly reduced after therapy; however, there were no statistically significant differences between treatments. If Actinobacillus actinomycetemcomitans was present before therapy, it was also present after treatment in both groups. The conclusion is that, in recall patients, local application of metronidazole and scaling and root planing showed similar clinical and microbiological effects without statistically significant differences.

Epithelial uptake and transport of cell-free human immunodeficiency virus type 1 and gp120-coated microparticles.

Cell-free human immunodeficiency virus type 1 (HIV-1) can be taken up and released by a monolayer of primary human gingival cells and remain infectious for CD4+ cells. Virus-sized latex particles covalently coated with purified native HIV-1 envelope glycoprotein gp120 are also transported through the primary epithelial cells. This process is significantly stimulated by increasing the intracellular cyclic AMP (cAMP) concentration. Inhibition experiments with mannan and alpha-methyl-mannopyranoside indicated that mannosyl groups are involved in the interaction between gp120 and gingival cells. An increase of cellular oligomannosyl receptors by incubation with the mannosidase inhibitor deoxymannojirimycin augmented transcellular transport of the gp120-coated particles. The results suggest that infectious HIV can penetrate gingival epithelia by a cAMP-dependent transport mechanism involving interaction of the lectin-like domain of gp120 and mannosyl residues on glycoproteins on the mucosal surface. Penetration of HIV could be inhibited by soluble glycoconjugates present in oral mucins.