Rivaroxaban vs. warfarin and renal outcomes in non-valvular atrial fibrillation patients with diabetes

AIMS

Vascular calcification is common in diabetic patients. Warfarin has been associated with renovascular calcification and worsening renal function; rivaroxaban may provide renopreservation by decreasing vascular inflammation. We compared the impact of rivaroxaban and warfarin on renal outcomes in diabetic patients with non-valvular atrial fibrillation (NVAF).

METHODS AND RESULTS

Using United States IBM MarketScan data from January 2011 to December 2017, we identified adults with both NVAF and diabetes, newly-initiated on rivaroxaban or warfarin with ≥12-month insurance coverage prior to anticoagulation initiation. Patients with Stage 5 chronic kidney disease (CKD) or undergoing haemodialysis at baseline were excluded. Differences in baseline covariates between cohorts were adjusted using inverse probability-of-treatment weighting (IPTW) based on propensity scores (absolute standardized differences <0.1 achieved for all after adjustment). Outcomes included incidence rates of emergency department/hospital admissions for acute kidney injury (AKI) and the composite of the development of Stage 5 CKD or need for haemodialysis. Patients were followed until an event, index anticoagulant discontinuation/switch, insurance disenrollment, or end-of-data availability. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox regression. We assessed 10 017 rivaroxaban (22.6% received a reduced dose) and 11 665 warfarin users. In comparison to warfarin, rivaroxaban was associated with lower risks of AKI (HR = 0.83, 95% CI = 0.74-0.92) and development of Stage 5 CKD or need for haemodialysis (HR = 0.82, 95% CI = 0.70-0.96). Sensitivity and subgroup analyses had similar effects as the base-case analysis.

CONCLUSION

Rivaroxaban appears to be associated with lower risks of undesirable renal outcomes vs. warfarin in diabetic NVAF patients.

CausalTAB: the PSI-MITAB 2.8 updated format for signalling data representation and dissemination

MOTIVATION

Combining multiple layers of information underlying biological complexity into a structured framework represent a challenge in systems biology. A key task is the formalization of such information in models describing how biological entities interact to mediate the response to external and internal signals. Several databases with signalling information, focus on capturing, organizing and displaying signalling interactions by representing them as binary, causal relationships between biological entities. The curation efforts that build these individual databases demand a concerted effort to ensure interoperability among resources.

RESULTS

Aware of the enormous benefits of standardization efforts in the molecular interaction research field, representatives of the signalling network community agreed to extend the PSI-MI controlled vocabulary to include additional terms representing aspects of causal interactions. Here, we present a common standard for the representation and dissemination of signalling information: the PSI Causal Interaction tabular format (CausalTAB) which is an extension of the existing PSI-MI tab-delimited format, now designated PSI-MITAB 2.8. We define the new term 'causal interaction', and related child terms, which are children of the PSI-MI 'molecular interaction' term. The new vocabulary terms in this extended PSI-MI format will enable systems biologists to model large-scale signalling networks more precisely and with higher coverage than before.

AVAILABILITY AND IMPLEMENTATION

PSI-MITAB 2.8 format and the new reference implementation of PSICQUIC are available online (https://psicquic.github.io/ and https://psicquic.github.io/MITAB28Format.html).

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

All-Cause Mortality Amongst Patients Undergoing Above and Below Knee Amputation in a Regional Vascular Centre within 2014-2015

BACKGROUND

Major lower limb amputation remains a common treatment for patients with peripheral vascular disease (PVD) in whom other measures have failed. It has been associated with high morbidity and mortality, including risks from venous thromboembolism (VTE).

METHODS

A two-year retrospective cohort study was conducted involving 79 patients who underwent major lower limb amputation (below- or above-knee amputation) between January 2014 and December 2015 in a single tertiary referral centre. Amputation procedures were performed for reasons relating to complications of PVD and/or diabetes mellitus. Patients were followed-up to investigate all-cause mortality rates and VTE events using the Northern Ireland Electronic Care Record database (mean follow-up time 17 months).

RESULTS

Of the 79 patients, there were 52 male and 27 female. Mean age at time of surgery was 72 years (range 34-99 years). Forty-six patients (58%) suffered from diabetes mellitus, 29 (35%) heart failure, 31 (39%) chronic kidney disease (CKD) and 10 (13%) chronic obstructive pulmonary disease (COPD). Twenty patients (25%) were on anticoagulant therapy, and 53 (67%) were on antiplatelet therapy.Thirty-five patients (44%) died during follow-up; mean age at death was 74 years. No statistically significant association was found between mortality rate and the level of amputation (p=0.3702), gender (p=0.3507), or comorbid diabetic mellitus (p=0.1127), heart failure (p=0.1028), CKD (p=0.0643) or COPD (p=0.4987).Two patients experienced radiologically-confirmed non-fatal pulmonary emboli and two patients developed radiologically-confirmed deep vein thrombosis.

CONCLUSIONS

The results are in agreement with current literature that amputation is associated with significant mortality, with almost half of the study population dying during follow-up. Further work should explore measures by which mortality rates may be reduced.

Encompassing new use cases - level 3.0 of the HUPO-PSI format for molecular interactions

BACKGROUND

Systems biologists study interaction data to understand the behaviour of whole cell systems, and their environment, at a molecular level. In order to effectively achieve this goal, it is critical that researchers have high quality interaction datasets available to them, in a standard data format, and also a suite of tools with which to analyse such data and form experimentally testable hypotheses from them. The PSI-MI XML standard interchange format was initially published in 2004, and expanded in 2007 to enable the download and interchange of molecular interaction data. PSI-XML2.5 was designed to describe experimental data and to date has fulfilled this basic requirement. However, new use cases have arisen that the format cannot properly accommodate. These include data abstracted from more than one publication such as allosteric/cooperative interactions and protein complexes, dynamic interactions and the need to link kinetic and affinity data to specific mutational changes.

RESULTS

The Molecular Interaction workgroup of the HUPO-PSI has extended the existing, well-used XML interchange format for molecular interaction data to meet new use cases and enable the capture of new data types, following extensive community consultation. PSI-MI XML3.0 expands the capabilities of the format beyond simple experimental data, with a concomitant update of the tool suite which serves this format. The format has been implemented by key data producers such as the International Molecular Exchange (IMEx) Consortium of protein interaction databases and the Complex Portal.

CONCLUSIONS

PSI-MI XML3.0 has been developed by the data producers, data users, tool developers and database providers who constitute the PSI-MI workgroup. This group now actively supports PSI-MI XML2.5 as the main interchange format for experimental data, PSI-MI XML3.0 which additionally handles more complex data types, and the simpler, tab-delimited MITAB2.5, 2.6 and 2.7 for rapid parsing and download.

Sex and breed affect plasma glucose, lactate, cortisol, meat quality but not muscle glycolytic potential of Dorper and Merino lambs

Response to pre-slaughter stress differs depending on animal-related factors such as sex and breed. The present study investigated breed and sex effects on plasma stress indicators, muscle glycolytic potential and the quality of meat from 8-month-old lambs of Dorper (n = 52) and Merino (n = 48) breeds. Blood samples were collected at exsanguination for the measurement of glucose, lactate and cortisol levels. Representative meat samples were collected from the Muscularis longissimus thoracis et lumborum for the measurement of glycogen, lactate, glycolytic potential levels, pH and colour coordinates. Results showed that the ewes had higher levels of plasma lactate, cortisol and meat pH than the rams, meaning that the ewes perceived the slaughter process to be more stressful compared with the rams. The Dorper also had higher levels of plasma lactate and lower meat lightness compared with the Merino breed. Significant sex and breed interactions on the meat pH45 min and colour coordinates were observed. Significant correlations were found among plasma cortisol, pH and colour. The results indicate that ewes and Dorper were more stressed than the rams and Merino breed respectively. In this study it can be concluded that the ewes and Dorper breed perceived the slaughter process to be more stressful compared with the rams and Merino breed.

Thermotolerance, health profile and cellular expression of HSP90AB1 in Nguni and Boran cows raised on natural pastures under tropical conditions

Boran (n=15) and Nguni (n=15) cows were used in a study to determine the effect of breed, age and coat colour on the concentration of heat shock protein 90 (HSP90AB1), physiological rectal and skin temperature, and markers of health. The cows were exposed to summer heat stress and Boran cows had higher significant (P<0.05) skin temperature (35.1±0.42°C) as compared to the Nguni cows (36.0±0.38°C). Nguni cows had higher body thermal gradients than the Boran cows. Boran cows had thicker skin (P<0.05) and longer hairs (24.3±2.26mm) than their Nguni counterparts (20.2±2.00mm). The HSP90AB1 concentration was increased in Boran cows, although breed had no significant (P>0.05) influence. Significantly (P<0.05) high urea and total cholesterol was recorded in Boran cows. Coat colour had a significant (P<0.05) effect on the weight and rectal temperature of the study animals. Coat colour and age had no significant effect (P>0.05) on the concentration of HSP90AB1, although older cows (≥9 years) had higher concentrations (5.4±1.29ng/ml). Age had a significant (P<0.05) effect on packed cell volume, neutrophil/lymphocyte, urea, total protein and gamma-glutamyl transferase whereas cows with ≥9 years had more concentrations than young ones. Age significantly (P<0.05) influenced hair length, skin temperature and the thermal gradients. Breed was positively correlated (P<0.001) to coat colour, age, body condition score, weight and temperature humidity index while negatively correlated to urea and total cholesterol. It was concluded that Nguni cows were more adaptable to hot environments than the Boran cows as the latter were unable to balance thermal load between their bodies and the environment.

Rice sucrose transporter1 (OsSUT1) up-regulation in xylem parenchyma is caused by aphid feeding on rice leaf blade vascular bundles

The role of the sucrose transporter OsSUT1 in assimilate retrieval via the xylem, as a result of damage to and leakage from punctured phloem was examined after rusty plum aphid (Hysteroneura setariae, Thomas) infestation on leaves from 3-week-old rice (Oryza sativa L. cv Nipponbare) plants. Leaves were examined over a 1- to 10-day infestation time course, using a combination of gene expression and β-glucuronidase (GUS) reporter gene analyses. qPCR and Western blot analyses revealed differential expression of OsSUT1 during aphid infestation. Wide-field fluorescence microscopy was used to confirm the expression of OsSUT1-promoter::GUS reporter gene in vascular parenchyma associated with xylem elements, as well as in companion cells associated with phloem sieve tubes of large, intermediate and small vascular bundles within the leaf blade, in regions where the aphids had settled and were feeding. Of great interest was up-regulation of OsSUT1 expression associated with the xylem parenchyma cells, abutting the metaxylem vessels, which confirmed that OsSUT1 was not only involved in loading of sugars into the phloem under normal physiological conditions, but was apparently involved in the retrieval of sucrose leaked into the xylem conduits, which occurred as a direct result of aphid feeding, probing and puncturing of vascular bundles. The up-regulation of OsSUT1 in xylem vascular parenchyma thus provides evidence in support of the location within the xylem parenchyma cells of an efficient mechanism to ensure sucrose recovery after loss to the apoplast (xylem) after aphid-related feeding damage and its transfer back to the symplast (phloem) in O. sativa leaves.

Gorham's disease of the maxilla: a case report

A case of Gorham's disease in the maxilla of a 56-year-old male patient is described. The clinical presentation, radiographic and histopathological features and treatment are presented. A discussion of the current understanding of this rare disease, based on review of the literature, is offered.

Prevalence of bovine tuberculosis in abattoirs of the littoral and Western highland regions of cameroon: a cause for public health concern

Bovine tuberculosis (BTB) is widespread but poorly controlled in Africa and M. bovis is posing threats to human health. The risk of cattle handlers to M. bovis prevalence and public health significance of BTB in Cameroon were assessed. Slaughter inspection records from major cities revealed that BTB detection rates in cattle from 0.18% to 4.25% and BTB lesions were most common. Analyses of tissues and sera confirmed BTB in 31% (Ziehl-Neelsen), 51% (culture), and 60% (antibody detection) of test cattle. Among cattle handlers, 81.9% were aware of BTB, 67.9% knew that BTB is zoonotic, and 53.8% knew one mode of transmission but over 27% consumed raw meat and/or drank unpasteurized milk. Respondents who had encountered tuberculosis cases were more informed about zoonotic BTB (P < .05). Tuberculosis is prevalent in cattle destined for human consumption in Cameroon with serious public health implications. Targeted monitoring of infected animal populations and concerted veterinary/medical efforts are essential for control.

Soybean meal alters autochthonous microbial populations, microvilli morphology and compromises intestinal enterocyte integrity of rainbow trout, Oncorhynchus mykiss (Walbaum)

Abstract Rainbow trout were fed either a diet containing fishmeal (FM) as the crude protein source or a diet containing 50% replacement with soybean meal (SBM) for 16 weeks. An enteritis-like effect was observed in the SBM group; villi, enterocytes and microvilli were noticeably damaged compared with the FM group. The posterior intestine microvilli of SBM-fed fish were significantly shorter and the anterior intestine microvilli significantly less dense than the FM-fed fish. Electron microscopy confirmed the presence of autochthonous bacterial populations associated with microvilli of both fish groups. Reduced density of microvilli consequently led to increased exposure of enterocyte tight junctions, which combined with necrotic enterocytes is likely to diminish the protective barrier of the intestinal epithelium. No significant differences in total viable counts of culturable microbial populations were found between the groups in any of the intestinal regions. A total of 1500 isolates were tentatively placed into groups or genera, according to standard methods. Subsequent partial 16S rRNA sequencing revealed species that have not been identified from the rainbow trout intestine previously. Compared with the FM group levels of Psychrobacter spp. and yeast were considerably higher in the SBM group; a reduction of Aeromonas spp. was also observed.

The reliability of a single pulse oximetry reading as a screening test for congenital heart disease in otherwise asymptomatic newborn infants

Routine pulse oximetry has been studied to detect children with otherwise undiagnosed congenital heart disease prior to nursery discharge. The reported sensitivities in asymptomatic patients have been less than expected and vary widely, bringing into question the reliability of the test. The purpose of this study was to assess whether routine pulse oximetry contributes to identifying patients with critical congenital heart disease and to determine the reliability of a single pulse oximeter reading in screening asymptomatic newborn infants. Between December 26, 2003, and December 31, 2005, three hospitals in west central Florida performed a pulse oximetry routinely on all newborns at the time of discharge. Patients diagnosed with critical congenital heart disease during the study period were identified to assess whether the pulse oximetry reading initiated their diagnosis. In one hospital, the pulse oximeter data were evaluated for reliability. Downloaded data were compared to a log compiled by the nursery personnel, first without (phase 1) and then with (phase 2) their knowledge and additional training. Results were characterized as reliable, probe placed but reading not verifiable, or no evidence of probe placement. Of the 7962 infants who received oximetry testing, there were 12 postnatal diagnoses of critical congenital heart disease. None was initially identified by routine pulse oximetry. Pulse oximetry reliability improved substantially between phase 1 and phase 2 (38 v. 60%, p < 0.0001). Optimal reliability (>95%) was obtained by a nurse with a degree of LPN or higher performing an assessment of at least 360 seconds. Routine pulse oximetry was neither reliable nor an important diagnostic tool in our cohort. Important human factors (probe placement time, oximetry training, and nursing degree) impact single determination pulse oximetry reliability. With routine surveillance and quality improvement, the reliability of this test can be increased. Future studies to determine the effectiveness of pulse oximetry screening for the diagnosis of congenital heart disease in the asymptomatic newborn population must address these factors. Until such a study demonstrates acceptable sensitivity and clinical value, universal screening should not be instituted.

Reliability of a single pulse oximetry reading as a screening test for congenital heart disease in otherwise asymptomatic newborn infants: the importance of human factors

BACKGROUND

The use of routine pulse oximetry to detect neonates with undiagnosed congenital heart disease before nursery discharge has been studied. The reported sensitivities with asymptomatic patients have been less than expected and vary widely, bringing into question the reliability of the test. This study aimed to assess whether routine pulse oximetry contributes to identifying patients with critical congenital heart disease, and to determine the reliability of a single pulse oximeter reading for screening asymptomatic newborn infants.

METHODS

Between December 26, 2003 and December 31, 2005, three hospitals in west central Florida performed pulse oximetry routinely on all newborns at the time of discharge. Patients who received a diagnosis of critical congenital heart disease during the study period were identified to assess whether the pulse oximetry reading initiated their diagnosis. In one hospital, the pulse oximeter data were evaluated for reliability. Downloaded data were compared to a log compiled by the nursery personnel, first without (Phase 1) and then with (Phase 2) their knowledge and additional training. The results were characterized as reliable, probe placed but reading not verifiable, or no evidence of probe placement.

RESULTS

Among the 7,962 infants who received oximetry testing, there were 12 postnatal diagnoses of critical congenital heart disease. None was initially identified by routine pulse oximetry. Pulse oximetry reliability improved substantially between Phases 1 and 2 (38% vs 60%; p < 0.0001). Optimal reliability (>95%) was obtained by a nurse with a licensed practical nurse degree or higher performing an assessment of at least 360 s.

CONCLUSION

Routine pulse oximetry was neither reliable nor an important diagnostic tool for our cohort. Important human factors (probe placement time, oximetry training, and nursing degree) have an impact on single-determination pulse oximetry reliability. With routine surveillance and quality improvement, the reliability of this test can be increased. Future studies to determine the effectiveness of pulse oximetry screening for the diagnosis of congenital heart disease in the asymptomatic newborn population must address these factors. Until such a study demonstrates acceptable sensitivity and clinical value, universal screening should not be instituted.

The expression of p53-induced protein with death domain (Pidd) and apoptosis in oral squamous cell carcinoma

The Pidd (p53-induced protein with death domain) gene was shown to be induced by the tumour suppressor p53 and to mediate p53-dependent apoptosis in mouse and human cells, through interactions with components of both the mitochondrial and the death receptor signalling pathways. To study the role of Pidd in clinical tumours, we measured its expression by quantitative reverse transcription-PCR in microdissected oral squamous cell carcinomas (OSCC) with and without p53 mutation. Tumour cell apoptosis was assessed by in situ terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling. Tumour proliferation was assessed by immunohistochemical staining for the Ki-67 antigen. We found a wide range of Pidd expression among OSCC. Statistical analysis revealed an association between Pidd expression and apoptotic index (Mann-Whitney test, P<0.001), consistent with a role of Pidd in apoptosis in this tumour type. Furthermore, we showed a positive correlation between apoptotic index and proliferative index that has not been previously described for OSCC. There was no correlation between Pidd expression and the p53 mutation status of these tumours, suggesting that Pidd expression may be regulated by p53-independent mechanisms. Further characterisation of these molecular defects in the control of proliferation and apoptosis should help in developing treatments that target OSCC according to their biological properties.

Use of self-prescribed nonprescription medications and dietary supplements among assisted living facility residents

OBJECTIVE

Describe the prevalence of self-prescribed use and misuse as well as users' opinions concerning nonprescription medications and dietary supplements in assisted living facilities.

DESIGN

Descriptive cross-sectional study.

SETTING

Two assisted living facilities (ALFs) in Oregon and Washington State.

PARTICIPANTS

Convenience sample of 45 ALF residents.

INTERVENTION

Chart reviews and face-to-face interviews.

MAIN OUTCOME MEASURES

Prevalence and types of use of self-prescribed over-the-counter (OTC) medications and dietary supplements; misuse of these products, and participants' opinions concerning use of these products.

RESULTS

Among 29 women and 16 men with a mean (+/- SD) age of 84.8 +/- 6.9 years and a mean of 9.9 +/- 6.4 years of education, 84.4% were using selfprescribed OTC medications and dietary supplements at the time of this study. A mean of 3.4 products was used per participant. Nutritional supplements were most frequently used (32% of products), followed by gastrointestinal products (17%), pain relievers (16.3%), herbals (14.4%), topical products (12%), and cold/cough products (8.5%). Potential misuse was identified in 23 (51%) of the participants. Problems in the use of products included duplication (70%), potential drug/disease/food interactions (20.8%), and other inappropriate use (9.1%). The majority (76%) of the participants believed the products were helpful in maintaining health, 56% of them wanted more product information, 49% sought product information from family and friends, 40% turned to their physicians and nurses for information, and 11% asked pharmacists for advice.

CONCLUSION

The use of nonprescription medications and dietary supplements among ALF residents was high, and simultaneous use of multiple products with the same active ingredient was the most prevalent problem. The residents turned to family and friends, physicians, nurses, and ALF staff for information on these products more frequently than they did to pharmacists.

Observer agreement in the grading of oral epithelial dysplasia

OBJECTIVES

To determine the extent of observer agreement in diagnosis of oral epithelial dysplasia (OED). Published studies of OED examiner agreement report relatively low agreement levels; however, these studies were limited by the methodologies employed.

METHODS

For this study, 64 slides were each independently examined twice by three oral pathologists. Consistency was assessed by determining intra- and interexaminer agreement. Conformity was assessed by using the modal diagnosis as a gold standard.

RESULTS

The group showed moderate interobserver agreement when grading the presence or absence of OED with a group-simple kappa (Ks) of 0.51 (95% CI = 0.42-0.61), and substantial agreement when using a 5-point ordinal scale with a group-weighted kappa (Kw) of 0.74 (95% CI = 0.64-0.85). The group showed fair to substantial intraexaminer agreement when assessing the presence or absence of OED, with Ks ranging from 0.22 to 0.78, and showing almost a perfect agreement using a 5-point ordinal scale, with Kw ranging from 0.82-0.96. Conformity with the comparison standard modal diagnosis was almost perfect, with pairwise Kw ranging from 0.81 to 0.92.

CONCLUSION

Overall, there was substantial intra- and interobserver consistency and almost perfect conformity in the grading of OED. Appropriate statistical methods are necessary to determine the degree of observer agreement.

In situ localization associates biologically active plant natriuretic peptide immuno-analogues with conductive tissue and stomata

Plant natriuretic peptide immuno-analogues (irPNP) have previously been shown to affect a number of biological processes including stomatal guard cell movements, ion fluxes and osmoticum-dependent water transport. Tissue printing and immunofluorescent labelling techniques have been used here to study the tissue and cellular localization of irPNP in ivy (Hedera helix L.) and potato (Solanum tuberosum L.). Polyclonal antibodies active against human atrial natriuretic peptide (anti-hANP) and antibodies against irPNP from potato (anti-StPNP) were used for immunolabelling. Tissue prints revealed that immunoreactants are concentrated in vascular tissues of leaves, petioles and stems. Phloem-associated cells, xylem cells and parenchymatic xylem cells showed the strongest immunoreaction. Immunofluorescent microscopy with fluorescein isothiocyanate (FITC)-conjugated goat anti-rabbit IgG supported this finding and, furthermore, revealed strong labelling to stomatal guard cells and the adjacent apoplastic space as well. Biologically active immunoreactants were also detected in xylem exudates of a soft South African perennial forest sage (Plectranthus ciliatus E. Mey ex Benth.) thus strengthening the evidence for a systemic role of the protein. In summary, in situ cellular localization is consistent with physiological responses elicited by irPNPs reported previously and is indicative of a systemic role in plant homeostasis.

O(6)-alkylguanine-DNA alkyltransferase DNA repair in mycobacteria: pathogenic and non-pathogenic species differ

SETTING

DNA repair genes assist the organism in maintaining DNA integrity in the face of environmental (mutagenic) stress. The genome sequences of M. tuberculosis and M. bovis demonstrate sequences suggestive of an O(6)-alkylguanine-DNA alkyltransferase DNA repair activity similar to that seen in almost all other bacterial and eukaryotic organisms. The near ubiquitousness of this gene implies an important function.

OBJECTIVE

Our aim was to ascertain whether mycobacteria exert an alkyltransferase response to mutagen (streptozotocin) stimulation and whether alkyltransferase activity is essential for mycobacterial survival.

DESIGN

Alkyltransferase activity in slow- and fast-growing mycobacterial species was determined in the presence and absence of sublethal concentrations of an alkylating agent streptozotocin. The intracellular survival and response to anti-tuberculosis drugs of an alkyltransferase knockout strain of M. bovis BCG was also determined.

RESULTS

We demonstrate the presence of O(6)-alkylguanine alkyltransferase (cellular methyltransferase activity) in mycobacterial species and that there is an inducible and constitutive form in fast-growing mycobacteria (M. smegmatis), whereas only the constitutive form exists in the pathogenic or slow-growing species (M. bovis BCG) under the conditions tested. The overall activity of the constitutive form is high. We also show that intracellular growth of M. bovis BCG in macrophages is reduced when the alkyltransferase gene is absent. The presence of alkyltransferase activity appears to assist the organism in reducing the effects of isoniazid, since interruption of the gene confers sensitivity to the drug.

CONCLUSIONS

We conclude that for the slow-growing mycobacteria, an inducible response is not essential as their ecological niche is stable and protected, but that the presence of the alkyltransferase activity confers a growth advantage in macrophages and offers some protection against antibiotics.

Benign cementoblastoma: a case report

The case of a 23-year-old with a benign cementoblastoma is presented. The clinicopathologic features, treatment and prognosis are discussed and a brief review of the literature is presented. Although this neoplasm is rare, the dental practitioner should be aware of the clinical features that will lead to its early diagnosis and treatment.

Patterns of CDKN2A gene loss in sequential oral epithelial dysplasias and carcinomas

The CDKN2A gene locus encodes two different proteins derived from alternative splicing. p16 (exons 1alpha, 2, and 3) acts as a G1 cell cycle regulator, and p14ARF (exons 1beta, 2, and 3) acts to modulate MDM2-mediated degradation of p53. Inactivation of p16 is a common finding in many cancers; however, there is little data on CDKN2A gene abnormalities in oral precancer. In this longitudinal study, we examined changes in the CDKN2A gene locus in sequential epithelial dysplasias and oral carcinomas from 11 patients. Genomic DNA was extracted from laser-microdissected lesional tissue, and exons 1alpha, 1beta, and 2 were analyzed by duplex PCR. Immunohistochemistry was done to identify p16 and p14ARF protein expression. Two adjacent polymorphic microsatellite markers were used for allelotyping. Homozygous deletion of exon 1alpha was identified in 2 of 17 (12%) precancerous lesions. Loss of either exon 1alpha, exon 2, or both was seen in seven of nine (78%) carcinomas. In five of these carcinomas, there was loss of only exon 1alpha. No case showed deletion of exon 1beta. In 5 of 11 patients, microsatellite markers showed differing patterns of allelic imbalance in the precancerous lesions and the subsequent carcinoma, suggesting a complex genetic pattern of progression from dysplasia to carcinoma. We conclude that during oral carcinogenesis homozygous deletion of exon 1alpha of the CDKN2A gene is common but that deletion of exon 2 and 1beta is less frequent. Moreover, our results suggest that the progression from oral precancer to cancer, in some cases, is more complex genetically than predicted by linear models of carcinogenesis.

Abnormalities of the ARF-p53 pathway in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is associated with heavy smoking and drinking, but the molecular pathway of tumorigenesis is not understood. Inactivation of the p53 tumor suppressor gene is likely to play an important role since p53 mutation is frequently found. The p14ARF tumor suppressor gene is functionally linked to p53, because it is activated by oncogenes and causes p53-dependent growth arrest and apoptosis. The relationship between p14ARF and p53 inactivation has not been described for OSCC. We studied 25 cases of OSCC to determine if there is an inverse correlation between p53 mutation and p14ARF inactivation by homozygous deletion or mutation. p53 mutation was found in 16 of 25 cases (64%), including nine missense and seven truncating mutations. While all cases with missense mutations showed abnormal accumulation of p53 protein, there were also five carcinomas which showed increased p53 staining in the absence of mutation. p14ARF deletion or mutation was found in eight cases (32%), six of which also demonstrated p53 mutation. Our findings indicate that OSCC often involves loss of both p14ARF and p53 function and suggest that inactivation of these two tumor suppressor genes are not functionally equivalent during tumorigenesis.

The information and communication society: how people will live and work in the new millennium

This paper analyses information and communication technology (ICT) and its relation to work organizations, human communication, stress, allocation issues, knowledge transfer and global villages. An interdisciplinary research programme on 'Computer technology and work life' was initiated and led by the author at Stockholm University in 1974, followed by many programmes in Sweden in the field. A theoretical framework was developed including two theoretical models, one more general, the other where the concepts and their interrelationships were specified. The models were tested empirically in three large work organizations in Sweden, representing three main historical periods of computer technology. It was also used as a model in discussing what might be desirable goals in the information society. The present fourth period, the 'Network period', is characterized by a convergence of three main technologies: computer, telecommunication and media. ICT is used in almost every activity and is embedded in many things. The author proposes a superimposed theoretical model reflecting 'ICT and the psychosocial life environment', a revised model of her initial models. Finally, future research is discussed with reference to theoretical models revised, and conclusions address major psychosocial processes, psychosocial life environments and a call for synthesis.

p53 gene mutations in sequential oral epithelial dysplasias and squamous cell carcinomas

Previous studies of oral cancer have suggested that alterations of the p53 tumour suppressor gene occur early in the precancerous stage of development. However, these observations have been based on cross-sectional assessment of abnormal p53 protein staining by immunohistochemistry and may not necessarily reflect gene changes. The purpose of this longitudinal study was to examine the changes in the p53 gene in progressive, sequential epithelial dysplasias and carcinomas from the oral cavity. The study analysed 24 formalin-fixed, paraffin-embedded tissue biopsies from ten patients with two or more temporally distinct lesions from the same site in the oral cavity with the diagnosis of hyperkeratosis, epithelial dysplasia, carcinoma in situ or squamous cell carcinoma. Exons 5-8 of the p53 gene were amplified from genomic DNA using intronic primers and directly sequenced using fluorescent-labelled primers. Standard immunohistochemistry with the DO7 monoclonal antibody was used to detect mutant and wild-type p53 protein. Mutations of the p53 gene were identified in 9 of 24 samples. Eight were missense mutations and one occurred at a splice site. In six patients, mutations of the p53 gene occurred late after the transformation of epithelial dysplasia to carcinoma. In two patients with progressive dysplasia, but who had yet to develop invasive carcinoma, p53 missense mutations occurred at the carcinoma in situ stage in one case and in a moderate dysplasia in the other. There was an inconsistent relationship between gene mutations and the level of p53 protein staining by immunohistochemistry. It is concluded that during oral carcinogenesis, p53 gene mutations seem to occur relatively late and are associated with transformation to the invasive phenotype.

Analysis of genomic integrity and p53-dependent G1 checkpoint in telomerase-induced extended-life-span human fibroblasts

Life span determination in normal human cells may be regulated by nucleoprotein structures called telomeres, the physical ends of eukaryotic chromosomes. Telomeres have been shown to be essential for chromosome stability and function and to shorten with each cell division in normal human cells in culture and with age in vivo. Reversal of telomere shortening by the forced expression of telomerase in normal cells has been shown to elongate telomeres and extend the replicative life span (H. Vaziri and S. Benchimol, Curr. Biol. 8:279-282, 1998; A. G. Bodnar et al., Science 279:349-352, 1998). Extension of the life span as a consequence of the functional inactivation of p53 is frequently associated with loss of genomic stability. Analysis of telomerase-induced extended-life-span fibroblast (TIELF) cells by G banding and spectral karyotyping indicated that forced extension of the life span by telomerase led to the transient formation of aberrant structures, which were subsequently resolved in higher passages. However, the p53-dependent G1 checkpoint was intact as assessed by functional activation of p53 protein in response to ionizing radiation and subsequent p53-mediated induction of p21(Waf1/Cip1/Sdi1). TIELF cells were not tumorigenic and had a normal DNA strand break rejoining activity and normal radiosensitivity in response to ionizing radiation.

Aberrant expression of cyclin A and cyclin B1 proteins in oral carcinoma

Cyclins play an important role in regulating the passage of dividing cells through critical checkpoints in the cell cycle. Aberrant expression of cyclin proteins has been found in a number of human cancers, including carcinomas of the head and neck, where amplification of the cyclin D1 gene is a common finding. The objective of this study was to examine cell cycle kinetics in oral carcinomas by determining the expression of the S phase protein cyclin A and the M phase protein cyclin B1. Routinely processed tissue sections of 50 oral squamous cell carcinomas from the floor of the mouth were stained by immunohistochemistry for cyclin A, cyclin B1 and Ki-67 proteins. Ten specimens of normal epithelium from the floor of the mouth were used as controls. The number of cells showing nuclear staining for cyclin A, cyclin B1 and Ki-67 proteins was determined by computer image analysis. There were 17 well-differentiated, 25 moderately differentiated and 8 poorly differentiated tumours. Mean counts for cyclin A (29.50+/-4.10, mean+/-95% CI), cyclin B1 (2.05+/-0.30) and Ki-67 (49.46+/-5.91) proteins in the carcinomas were significantly higher than counts for the normal epithelial controls (cyclin A: 9.30+/-1.72; cyclin B1: 1.01+/-0.36; Ki-67: 17.40+/-4.17). For cyclin A, cyclin B1 and Ki-67, mean staining scores for all tumour grades were significantly higher than controls. There was a strong correlation between Ki-67 and cyclin A scores in all tumour groups (r2=0.68); however, the correlations between cyclin B1 and cyclin A scores (r2=0.35) and between cyclin B1 and Ki-67 scores (r2= 0.39) were weak. We conclude that there is overexpression of cyclin A and cyclin B1 proteins in oral carcinoma. Furthermore, the poor correlations for cyclin B1 scores with other cell cycle indices suggest that there may be aberrant cell cycle progression at the G2/M checkpoint in oral carcinomas.

Increased P-glycoprotein messenger RNA stability in rat liver tumors in vivo

P-glycoproteins (Pgp) are comprised of a small family of plasma membrane proteins whose abundance in cultured cells is often associated with the multidrug resistance phenotype. Overexpression of Pgp has been observed in many types of human cancers, but the molecular basis for this overexpression has not been established. We have used primary monolayer cultures of adult rat hepatocytes and a stepwise model of rat liver carcinogenesis to study the regulation of Pgp gene expression. We observed a marked overexpression of Pgp, specifically the class II Pgp, in both systems. In addition, we observed that a number of unrelated genes including alpha-tubulin, beta-actin, gamma-actin, cytokeratin 8, cytokeratin 18, and c-myc are overexpressed in cultured hepatocytes, and they are also overexpressed during liver carcinogenesis and in transplantable tumors. Nuclear run-on assays showed no increase in the transcriptional activity of Pgp genes in transplantable liver tumors compared to normal liver. Studies of in vivo mRNA stability, however, revealed that all three Pgp mRNAs were relatively stable in transplantable liver tumors (t(1/2) > 12 h), in contrast to what was found in normal liver (t(1/2) < 2 h). In addition, mRNA for several other genes, including alpha-tubulin, c-myc, and cyclin D1, all appear to be stabilized in the tumors. These findings suggest that the overexpression of Pgp genes in rat liver tumors may be the result of a mechanism involving stabilization of a diverse group of mRNAs.

Computer-controlled laser ablation: a convenient and versatile tool for micropatterning biofunctional synthetic surfaces for applications in biosensing and tissue engineering

This paper describes laser-based methods for preparing micropatterns of bioactive molecular species in self-assembled monolayers (SAMs) and micropatterns of proteins and other biological molecules immobilized on solid substrates. Applications of these micropatterned surfaces in multianalyte biosensing and tissue engineering are emphasized. The focus of the paper is on the use of a computer-controlled laser ablation system comprising a research-grade inverted optical microscope, a pulsed nitrogen-pumped dye laser emitting at 390 nm, a programmable sample stage, and the computerized control system. The laser system can be implemented in a typical biosensor or tissue culture laboratory to enable the facile and reproducible fabrication of micropatterned surfaces by several methods. Various methods for patterning are discussed with examples given and emphasis placed on (1) laser ablation in the fabrication of photolithography masks, (2) electrochemical patterning of SAMs, and (3) laser desorption of SAMs. The relative merits of each technique are discussed with respect to application in fabrication of active surfaces for biosensing and tissue culture applications.

Reduced levels of the cell-cycle inhibitor p27Kip1 in epithelial dysplasia and carcinoma of the oral cavity

Recent studies have shown that the cyclin-dependent kinase (cdk) inhibitors play important roles in cell cycle progression in normal cells. Alterations in the cdk inhibitors also appear to be important in cancer development in a number of human tumors. p27Kip1 is a member of the CIP/KIP family of cdk inhibitors that negatively regulates cyclin-cdk complexes. Reduced levels of p27Kip1 protein have been identified in a number of human cancers, and in some cases reduced p27Kip1 is associated with an increase in proliferative fraction. In the present study, we examined p27Kip1 protein by immunohistochemistry in 10 normal and 36 dysplastic epithelia and in 8 squamous cell carcinomas from one anatomical site within the oral cavity, the floor of the mouth. Proliferative activity was assessed in serial sections by determining the expression of the cell cycle proteins Ki-67 and cyclin A. p27kip1 protein was significantly reduced in oral dysplasias and carcinomas compared with that in normal epithelial controls. In addition, there was a significant reduction in p27Kip1 protein between low- and high-grade dysplasias, suggesting that changes in p27Kip1 expression may be an early event in oral carcinogenesis. There was increasing expression of Ki-67 and cyclin A proteins with increasingly severe grades of dysplasia compared with normal controls. Although there was a strong correlation between Ki-67 and cyclin A scores (r2= 0.61) for all categories of disease, there was a weak negative correlation between Ki-67 and p27Kip1 levels (r2 = 0.29) and between cyclin A and p27Kip1 levels (r2 = 0.25). In conclusion, this study has found that a reduction in the proportion of cells expressing p27Kip1 protein is frequently associated with oral dysplasia and carcinoma from the floor of the mouth. Furthermore, reductions in p27Kip1 levels are associated with increased cell proliferation, although other changes likely contribute to altered cell kinetics during carcinogenesis at this site.

Neurotoxicologic examination of rats exposed to 1,1,2,2-tetrachloroethylene (perchloroethylene) vapor for 13 weeks

Large evoked potential and EEG changes occurred in a pilot study in Fischer 344 rats during exposure to 800 ppm of 1,1,2,2-tetrachloroethylene [perchloroethylene (Perc)], a cleaning solvent with anesthetic properties. In the main study, rats were evaluated for persistent nervous system effects the week following exposure to 0, 50, 200, or 800 ppm Perc for 6 h/day, 5 days/week, for 13 weeks. The only effect related to treatment was in the flash evoked potential (FEP-V), recorded from the visual cortex. The longer latency potentials (N3) of the FEP-V had a greater amplitude in the 800 ppm Perc group. The FEP-Vs were of normal shape and latency. Although mild neurotoxicity could not be ruled out completely, amplitude changes in N3 can occur for a variety of psychophysiological reasons other than neurotoxicity. Consequently, as a stand-alone finding, the toxicologic significance of the larger FEP in the 800 ppm exposure group was unknown. Other data did not support a diagnosis of neurotoxicity. No treatment-related alterations were noted in expanded clinical observations, in the FEP recorded from the cerebellum (as opposed to visual cortex FEP-V), or in auditory, somatosensory, or caudal nerve evoked potentials. No treatment-related lesions were noted during histopathologic examination of eyes, optic nerves, optic tract, or multiple sections of brain, spinal cord, peripheral nerves, or limb muscles. The no-observed-effect-level (NOEL) was 200 ppm, based on increased amplitude of the longer latency potentials of the FEP at 800 ppm.

Patterns of p53 and Ki-67 protein expression in epithelial dysplasia from the floor of the mouth

Oral squamous cell carcinoma develops through a series of precancerous stages manifested at the microscopic level as epithelial dysplasia. Mutation of the p53 tumour suppressor gene is thought to be an important component of oral carcinogenesis. p53 regulates cell proliferation and DNA repair by inhibiting the cell cycle at G1/S; loss of p53 function may therefore lead to aberrant cell kinetics. To date, no studies have examined the relationship between p53 protein and alterations in cell kinetics in oral epithelial dysplasia from a single anatomical site. Serial sections were studied from 40 routinely processed biopsy specimens of epithelial dysplasia from the floor of the mouth. The expression of p53 protein was determined by immunohistochemistry and cell proliferation was studied by immunostaining for the cell cycle-dependent protein Ki-67. The number of positive cells per millimetre of basement membrane was determined using computer image analysis and compared with site-matched normal controls. The mean p53 labelling index (LI) in normal mucosa was low, 3.48 +/- 0.92 [mean +/- 95 per cent confidence interval (CI)], and increased sharply in the transition from mild (42.49 +/- 21.71) to moderate (104.86 +/- 51.39) epithelial dysplasia. The mean p53 LI for severe dysplasia was 119.09 +/- 56.50. Differences were also observed in the distribution of p53-positive cells between grades of dysplasia, with the development of compact p53-positive foci in severe dysplasia. Mean proliferative indices, as determined by Ki-67 expression, were significantly associated with grade of epithelial dysplasia. Furthermore, there was a significant correlation between p53 LI and Ki-67 score (r2 = 0.37, P = 0.01). It is concluded that altered p53 protein expression is probably an early event in oral carcinogenesis in the floor of the mouth and is associated with dysregulation of cell proliferation at this site.

Sensitive immunofluorescence detection of the expression of P-glycoprotein in malignant cells

Because reversal of multidrug resistance increases chemotoxicity, early detection of low P-glycoprotein expression is clinically relevant for justifying early treatment of those patients that might benefit most from reversal therapy. We elected to score P-glycoprotein in single tumor cells, because the gene is rarely amplified, mRNA levels do not necessarily correlate with protein levels, and many normal hematopoietic or stroma cells within tumors and leukemic marrows also express P-glycoprotein. We enhanced the "signal-to-noise" ratio for detecting low P-glycoprotein levels by a novel complex made by pre-incubating mouse peroxidase-antiperoxidase, used solely to provide a stable framework for attaching multiple DTAF-labeled F(ab')2 fragments of rabbit antimouse IgG. We improved specificity by using both C219 and C494, which are directed against separate internal P-glycoprotein epitopes. We standardized staining with two series of negative and positive controls, in which P-glycoprotein was quantified by immunoblot, and confirmed sensitivity by staining a low-expression cell line and "mixed" samples containing small numbers of positive cells. We measured P-glycoprotein by flow cytometry, examining aliquots by differential interference contrast microscopy to identify malignant cells, in which we confirmed P-glycoprotein staining by fluorescence microscopy. We detected low P-glycoprotein expression in clinical samples of leukemic blasts, distinguishing them from normal P-glycoprotein-expressing hematopoietic cells. This assay may be valuable for early diagnosis of low, but potentially important expression of P-glycoprotein, thereby allowing early application of reversal therapy.

Identification of a new P-glycoprotein-like ATP-binding cassette transporter gene that is overexpressed during hepatocarcinogenesis

The liver is remarkably insensitive to a variety of cytotoxins and expresses a number of known drug resistance genes. To isolate new P-glycoprotein (Pgp)-related genes, we screened a normal rat liver cDNA library at low stringency with a MDR1 cDNA fragment containing the P-loop and ATP binding site. We isolated a novel cDNA closely related to the Pgps that is dramatically increased in hepatic neoplasia and refer to it as P-glycoprotein-related protein (PRP). The predicted protein shows PRP to be a member of the ATP-Binding Cassette (ABC) family of proteins, and a multisequence comparison of the nucleotide binding domain and the ABC family signature sequences reveals that PRP sequences are highly conserved with the greatest similarity to the yeast heavy metal transporter encoded by hmtl. However, the hydropathy plot analysis suggests that PRP does not have any prominent membrane-spanning domains and thus is not typical of ABC transporters. The PRP transcript is detected in many normal tissues. In the H35 hepatoma cell line, PRP was overexpressed compared to normal liver. Southern blot analysis of DNA from the H35 rat hepatoma cells reveals that the PRP gene was amplified compared to normal liver. The orotic acid model of hepatocarcinogenesis was used to determine if during stepwise progression to liver cancer, PRP changed with hepatocarcinogenesis. At the hyperplastic nodule stage, PRP expression was increased over its expression in normal surrounding liver. More dramatic increases in PRP expression were found in frank hepatic carcinomas. Cumulatively, these studies are the first to link a novel ABC family member to the hepatic neoplastic process, a role that may be recapitulated in other cells, considering the ubiquitous expression of PRP.

Ostrich (Struthio camelus) carboxypeptidase B: purification, kinetic properties and characterization of the pancreatic enzyme

Carboxypeptidase B has been isolated from numerous mammalian and invertebrate species. In contrast, very little is known about carboxypeptidases of avian origin. To provide information for a comparative study, we have undertaken an investigation of the kinetic and physical properties of ostrich carboxypeptidase B. Carboxypeptidase B from the pancreas of the ostrich was purified by water extraction of acetone powder and aminobenzylsuccinic acid affinity and hydroxylapatite chromatography. The effects of pH and temperature on CPB activity were examined. K(i)-values for numerous inhibitors (PCI, ABSA, hipp-D-lys, epsilon-aminocaproic acid, D-arg and 3-phenylproprionic acid) and kinetic parameters (K(m), k(cat) and k(cat)/K(m)) for several substrates (hipp-arg, hipp-lys, FAAA, FAAL and hipp-AA) were determined. N-terminal sequencing and amino acid analysis were also performed. Purified ostrich carboxypeptidase B was assessed to be homogeneous by SDS-PAGE with a M(r) value of approx. 35,000. For ostrich carboxypeptidase B the K(m) values for the different substrates were of the same order as those reported for other species, whereas the k(cat) values were 8- to 21-fold lower than the reported values. FAAA and hipp-AA were the preferred substrates. PCI was the most effective inhibitor, with a K(i) in the nM region, and no inhibition was shown with 3-phenylpropionic acid. The N-terminal sequence showed a high degree of homology when aligned with CPB from other species. Amino acid analysis showed significantly lower levels of Asx and Cyh and higher levels of Trp and Leu when compared with other species. Ostrich carboxypeptidase B would appear to show many physical, chemical and kinetic properties similar to those of other known carboxypeptidases.