Application of Radiomics to the Differential Diagnosis of Temporal Bone Skull Base Lesions: A Pilot Study

BACKGROUND

Temporal bone skull base pathologies represent a complex differential because they can be radiographically obscure and difficult to diagnose without biopsy. Radiomics involves the use of mathematical quantification of imaging data beyond simple intensity, size, and location to inform diagnosis and prognosis. We examined the feasibility of using radiomic parameters to help predict temporal bone tumor type.

METHODS

A total of 117 radiomic parameters were analyzed from 5 magnetic resonance imaging sequences (T1 without contrast, T1 with contrast, T2, fluid-attenuated inversion recovery, apparent diffusion coefficient [ADC]) for each tumor. Statistical analysis was used to delineate known primary, metastatic/secondary, and lymphoma lesions using radiomics.

RESULTS

The mean tumor volumes for the 14 primary, 12 secondary, and 8 lymphoma lesions were 2.98 ± 2.11, 3.28 ± 2.31, and 12.16 ± 7.1 cm³, respectively (P = 0.2). No significant differences in mean intensity values for any sequence helped distinguish tumors (P > 0.05), but 6 radiomic parameters were significantly correlated with diagnostic accuracy. Discriminant analysis using a stepwise algorithm generated a model where radiomic parameters for T1 cluster prominence, ADC dependence nonuniformity, T1 with contrast zone percentage, and ADC informational measure of correlation 2 achieved the best predictive model (P = 0.0001). These significant characteristics were often indirect measures of tumor heterogeneity on different magnetic resonance imaging sequences.

CONCLUSIONS

These data suggest that quantitative measures of tumor heterogeneity can be discriminatory of pathology and might be integrated into clinical workflow. Although this pilot study requires further validation, these data support the exploration of radiomics in temporal bone radiographic diagnostics.

Imaging spectrum of extracranial arterial vascular pathology: pearls for the radiologist

Non-invasive imaging plays an increasingly important role in assessing the extracranial vasculature. The applications of computed tomography angiography (CTA) and magnetic resonance angiography (MRA) continue to expand with growing demand for stroke imaging and anatomical assessment preceding vascular intervention. Imaging of the neck is performed for a variety of clinical indications with different imaging protocols. Even on non-dedicated vascular imaging, such as soft-tissue studies, the neck vessels and the proximal aortic arch are readily evaluable, providing an opportunity to promptly identify critical vascular abnormalities with significant therapeutic implications. Vascular abnormalities can have non-specific clinical signs and symptoms resulting in delays in both diagnosis and treatment. Understanding the common locations and appearances of vascular pathologies will help the radiologist to develop a systematic search strategy for evaluating neck imaging. Not only is identifying the pathology of paramount importance but also understanding how imaging further prognosticates and determines treatment options. As imaging techniques advance, further vascular radiological features are recognised with therapeutic implications, particularly for stroke. Such features include plaque morphology and vulnerability with imaging helping to identify those at high risk of stroke and recurrent strokes. Using clinical cases from a quaternary care academic medical centre a spectrum of clinically relevant arterial pathologies and associated features that could add further benefit to the radiology report are illustrated. A suggested systematic approach to evaluating the vasculature on neck imaging is also presented.

Orbital invasion routes of non-melanoma skin cancers and survival outcomes

PURPOSE/OBJECTIVES

Overall non-melanoma head and neck skin cancer has a good prognosis; however, rarely patients have an aggressive variant which results in orbital invasion via perineural spread or direct extension. Despite these consequences, there are limited published studies defining this clinical entity. The main objectives of the current study are to describe orbital invasion patterns of non-melanoma head and neck skin cancers and their impact on survival.

METHODS

Retrospective case series from a tertiary-care, academic institution performed between 2004 and 2014. Demographic and tumour characteristics are reported as well as patterns of orbital invasion, types of treatments received, and survival outcomes.

RESULTS

There were 17 consecutive patients with non-melanoma skin cancer and orbital invasion who met inclusion criteria. Average age at orbital invasion diagnosis was 70.8 years old. 76% were male. Mean follow-up time was 28.5 months. Of these patients, 71% had squamous cell carcinoma and 29% had basal cell carcinoma. Brow (41%) was the most common primary sub-site followed by cheek (23%) and temple (12%). 76% of patients had a history of prior treatment. The lateral orbital wall (41%) was the most common site of invasion, followed by the medial orbital wall (29%) and antero-superior invasion (23%). Age, histology, and location of orbital invasion were associated with disease-specific and overall survival.

CONCLUSION

Orbital invasion for non-melanoma head and neck skin cancers creates a treatment dilemma and the patterns of invasion are described. In addition, the location of orbital invasion is associated with survival outcomes.

How can additional secondary data analysis of observational data enhance the generalisability of meta-analytic evidence for local public health decision making?

This paper critically explores how survey and routinely collected data could aid in assessing the generalisability of public health evidence. We propose developing approaches that could be employed in understanding the relevance of public health evidence, and investigate ways of producing meta-analytic estimates tailored to reflect local circumstances, based on analyses of secondary data. Currently, public health decision makers face challenges in interpreting global review evidence to assess its meaning in local contexts. A lack of clarity on the definition and scope of generalisability, and the absence of consensus on its measurement, has stunted methodological progress. The consequence of failing to tackle generalisability means that systematic review evidence often fails to fulfil its potential contribution in public health decision making. Three approaches to address these problems are considered and emerging challenges discussed: (1) purposeful exploration after a review has been conducted, and we present a framework of potential avenues of enquiry and a worked example; (2) recalibration of the results to weight studies differentially based on their similarity to conditions in an inference population, and we provide a worked example using UK Census data to understand potential differences in the effectiveness of community engagement interventions among sites in England and Wales; (3) purposeful exploration before starting a review to ensure that the findings are relevant to an inference population. The paper aims to demonstrate how a more nuanced treatment of context in reviews of public health interventions could be achieved through greater engagement with existing large sources of secondary data.

Laryngeal actinomycosis

Actinomyces odontolyticus, a component of normal human flora, has been implicated in cervicofacial actinomycosis, which most commonly involves the perimandibular soft tissues and is characterized by slowly progressive abscess and sinus tract formation. Actinomycosis has rarely been reported to involve the larynx, and the imaging findings of laryngeal involvement have not been reported. We present a case of laryngeal actinomycosis with findings on computed tomography, magnetic resonance imaging, and positron emission tomography.

Passive seismic experiment

Seismometer operation for 21 days at Tranquillity Base revealed, among strong signals produced by the Apollo 11 lunar module descent stage, a small proportion of probable natural seismic signals. The latter are long-duration, emergent oscillations which lack the discrete phases and coherence of earthquake signals. From similarity with the impact signal of the Apollo 12 ascent stage, they are thought to be produced by meteoroid impacts or shallow moonquakes. This signal character may imply transmission with high Q and intense wave scattering, conditions which are mutually exclusive on earth. Natural background noise is very much smaller than on earth, and lunar tectonism may be very low.

Myxoma of the vomer bone

Myxomas of bone in the head and neck are rare tumors. We present a 68 year old female with pain and epistaxis who was found to have the first reported case of a myxoma arising within the vomer bone. Some atypical magnetic resonance imaging features are described, however, myxoma imaging features are often non-specific and typically evoke a benign differential diagnosis. Surgical excision is the treatment of choice.

Distribution and determinants of risk of teenage motherhood in three British longitudinal studies: implications for targeted prevention interventions

PURPOSE

In order to consider the potential contribution of universal versus targeted prevention interventions, the authors examined what is the distribution of established risk variables for teenage motherhood? from where in these distributions do births arise? and how does this distribution/determination of risk vary between studies?

METHODS

Secondary data analysis of three British longitudinal studies.

RESULTS

For all cohorts and variables, the 'risk' category was the least frequent. Continuous risk factors were normally distributed. A high rate of teenage motherhood within a risk category often translated into low 'contribution' to the overall rate (eg, expectation to leave school at the minimum age among the 1989/1990-born cohort) and vice versa. Most young women had a low probability of teenage motherhood. For any targeting strategy, combining risk factors and a low threshold of predicted probability would be necessary to achieve adequate sensitivity. Assessing between-cohort applicability of findings, the authors find that the numbers of teenage parents is poorly estimated and estimates of the variability and direction of risk may also be inadequate.

CONCLUSIONS

With reference to a number of established risk factors, there is not a core of easily identifiable multiply disadvantaged girls who go on to constitute the majority of teenage mothers in these studies. While individual risk factors are unlikely to enable targeting, a composite may have some limited potential, albeit with a low threshold for 'risk' and with the caveat that evidence from one population may not inform good targeting in another. It is likely that universal approaches will have more impact.

Work, permanent sickness and mortality risk: a prospective cohort study of England and Wales, 1971-2006

BACKGROUND

In recent decades, labour market participation has fallen in men, with large amounts of this decline accounted for by increases in permanent sickness. There is speculation that the rising numbers of permanently sick incorporate more people with less severe conditions than was previously the case. This paper examines the relationship between labour market position and subsequent mortality around State Pension Age.

METHODS

Using linked census and death records in the ONS Longitudinal Study, samples of men aged 55-69 and women aged 50-64 were selected from each decennial census, 1971-2001 and their health followed up. Differences between the employed, unemployed and economically inactive in age-specific death rates, Standardised Mortality Ratios and odds of reporting limiting long-term illness were examined.

RESULTS

Labour market activity in late middle age has changed since 1971. For example, the proportion of men employed at ages 60-64 years has fallen by 39%, and the proportion permanently sick has more than doubled. Despite this change, there has been stability in the RR of mortality between labour market positions. Working people have the lowest risk of premature death, while, relative to working people, the permanently sick continue to have mortalities around three times higher among men and four to five times higher among women.

CONCLUSION

The evidence does not support the notion that the permanently sick are becoming less seriously ill. The persistence of the group's raised mortality suggests that measures aimed at encouraging later life employment should ensure provision of work environments suitable for people with chronic illnesses.

Parosteal osteosarcoma: Case report and review of the literature

BACKGROUND

The majority of osteosarcoma cases of the head and neck are high-grade lesions. We present a case and discuss the diagnostic and therapeutic implications of a rare low-grade parosteal osteosarcoma of the maxilla.

METHODS

A 32-year-old man presenting to the Head and Neck Surgical Oncology clinic with a 1-year history of a firm palatal mass. Evaluation clinically and radiographically raised the suspicion of an osteosarcoma.

RESULTS

A partial maxillectomy revealed a parosteal osteosarcoma with negative margins. No adjuvant therapy was recommended, and the patient remains without evidence of local recurrence after 3 years.

CONCLUSIONS

Parosteal osteosarcomas of the head and neck region are rare, low-grade variants of osteosarcoma, but have the potential to recur with simple local excision. Clinical and radiographic features are diagnostically helpful. Definitive diagnosis comes from histopathology, and wide local resection should be employed as the optimal treatment.

Class, Cohort, and Consumption: The British Experience of the Third Age

OBJECTIVE

This study examines the relative effect of historical and social class location on engagement in consumerism within two different cohorts of retired people in the United Kingdom.

METHODS

With use of self-reported data from the retired members of a nationally representative survey, an index of consumption was constructed. Its internal reliability was analysed and analyses of variance performed to examine the impact of class of origin, cohort, and class at exit on levels of self-reported "consumerism."

RESULT

The index demonstrated sufficient internal reliability to provide an operational measurement of "consumerism" within this retired population. Analyses of variance confirmed that class at exit and cohort but not class of origin contributed significantly to variation in levels of consumerism. These effects were not mediated by cohort differences in health.

DISCUSSION

Occupational standing immediately before retirement was associated with "consumerism" after retirement. This is unsurprising. The results also show that birth cohort exercised a stronger historical influence on current consumption in later life than did class background (i.e., paternal social class). This supports our thesis that the limited but increasing immersion in mass consumer society of successive cohorts who were born and grew up earlier in the 20th century continues to be reflected in levels of "consumerism" in retirement.

Person, place or time? The effect of individual circumstances, area and changes over time on mortality in men, 1995-2001

This article uses the ONS Longitudinal Study to explore, for a cohort of adult males who were aged 26 or over in 1971, the relative influence on mortality in 1995-2001 of their place of residence and individual socioeconomic circumstances, at three censuses over a 20-year period. Factors examined in this analysis include social class, neighbourhoo deprivation (at ward level), unemployment, residence in the South East region in 1971 or 1981 housing tenure, and change in social class and housing tenure between 1971 and 1991. The variation in mortality attributable to the local authority district of residence in 1991 was also investigated.

Social inequalities in health by individual and household measures of social position in a cohort of healthy people

STUDY OBJECTIVE

It is increasingly recognised that different dimensions of social inequality may be linked to health by different pathways. Furthermore, factors operating at the individual level such as employment conditions may affect health in a different way from household level factors. The paper examines the associations between self rated health and four measures of social position- occupational class, household social advantage, personal and household income.

DESIGN

Multilevel logistic regression models were used to predict self rated health using longitudinal data from the British Household panel survey (BHPS) with respondents nested within households. Separate analyses were carried out for economically active and inactive respondents.

SETTING

Interview based surveys of adults living within households that are representative of British households.

PARTICIPANTS

Adult respondents from the BHPS.

MAIN RESULTS

Occupational class has relatively strong effects on the self rated health of the economically active, although household level factors also seem to influence their health. Household social advantage has relatively strong effects on the self rated health of the economically inactive.

CONCLUSIONS

The paper found evidence in support of the view that different dimensions of social inequality have different pathways to self rated health. There are unexplained similarities in health between household members, which require further investigation.

Application of a novel human cervical mucin-based assay demonstrates the absence of increased mucinase activity in bacterial vaginosis

Enzymes produced in bacterial vaginosis (BV) have been proposed as possible mediators of pre-term birth. Most studies have concentrated on mid-trimester measurements of enzyme activity, and utilize synthetic substrates to measure enzyme activity, which may not accurately represent mucinase activity in vivo. We have developed a novel ELISA mucinase assay using biotinylated human cervical mucin as a substrate. The assay is rapid, sensitive and can be used to screen large numbers of samples. The new assay has been used to assess vaginal mucinase activities in 92 women <14 weeks gestational age with and without BV. No differences in mucinase activity were detected between normal and BV groups while significant elevation of sialidase and other glycosidases was confirmed as reported before. This study shows that significant mucinase activity is a normal event in the mucus barrier, but does not reflect changes identified for individual enzyme activities associated with BV.

Mucinases and sialidases: their role in the pathogenesis of sexually transmitted infections in the female genital tract

BACKGROUND

Mucinases and sialidases contribute to the process of invasion and colonisation in many conditions and infections of the female reproductive tract by degrading the protective cervical mucus. The role of hydrolytic enzymes in the pathogenesis of sexually transmitted diseases and their effect on cervical mucus are discussed in this review.

METHODS

Articles were searched for using the keywords "sialidase," "mucinase," "protease," and "sexually transmitted infections." As well as review and other articles held by our group, searches were conducted using PubMed, Grateful Med, and the University of Bath search engine, BIDS.

RESULTS

Numerous publications were found describing the production of hydrolytic enzymes in sexually transmitted diseases. Because the number of publications exceeded the restrictions imposed on the size of the review, the authors selected and discussed those which they considered of the most relevance to sexually transmitted infections.

Podocyte depletion and glomerulosclerosis have a direct relationship in the PAN-treated rat

BACKGROUND

Podocytes are highly differentiated glomerular epithelial cells with limited potential to divide. They are responsible for maintaining and supporting the glomerular basement membrane so as to facilitate efficient filtration. The hypothesis tested was whether the development of glomerulosclerosis in the puromycin aminonucleoside (PAN)-treated rat could be attributed to podocyte depletion.

METHODS

PAN was injected in Sprague-Dawley rats once, twice, or three times at 30-day intervals. Podocytes were counted in glomeruli using immunoperoxidase histochemistry and antibodies to both GLEPP1 (PTPRO) and WT-1. Podocytes were assayed in urine using reverse transcription-quantitative polymerase chain reaction (RT-QPCR). Glomerular areas were measured by computerized morphometry.

RESULTS

In a preliminary experiment, a single injection of PAN caused a reduction in the glomerular podocyte count by 25%. Additional independent confirmation that podocytes were lost from glomeruli after PAN injection was obtained identifying detached podocytes in Bowman's space, measurement of nephrin and GLEPP1 mRNAs in urine, ultrastructural analysis of glomeruli, and identification of TUNEL-positive apoptotic podocytes in glomeruli. In a second experiment, sequential podocyte depletion by 15, 31, and 53% was achieved by the administration of one, two, or three injections of PAN at 30-day intervals. The region of the glomerulus devoid of podocytes developed glomerulosclerosis, and this area progressively increased as podocytes were progressively depleted. The correlation coefficient (r(2)) value for the relationship between percent podocyte depletion and glomerulosclerotic area was 0.99. The Y intercept of this plot showed that glomerulosclerosis was initiated when only 10 to 20% of podocytes were lost.

CONCLUSION

This report supports the growing body of data linking glomerulosclerosis directly to a reduction in relative podocyte number [increased glomerular area per podocyte (GAPP)]. It raises important questions related to the mechanisms of podocyte loss, strategies for prevention of podocyte depletion, and the prevention of progression of glomerular diseases.

Study status consistency and duplicate-read protection in a distributed architecture

This presentation will discuss the benefits and pitfalls of implementing a study status and duplicate-read protection mechanism within a distributed picture archiving and communication system (PACS) architecture. There are many advantages to a distributed PACS network in which image studies are proactively pushed to reading stations before they are required by a radiologist. The absence of a central server, which serves on demand, makes managing study status and protecting against duplicate reads challenging. The system to manage study status and read access must be efficient, robust, and easy to administer. A system is presented that accomplishes these goals while maintaining the advantages of a distributed architecture.

METHODS

The basic workflow of the system is that image studies acquired at a modality device are automatically sent to an archive server. Using a set of advanced routing rules, the archive automatically routes studies to diagnostic workstations where studies are candidates for diagnostic read. The workstations display a list of all local studies available for reading. A monitor application running on the workstations coordinates access to studies for diagnostic read. Once the status of a study has been changed, the workstations on the networks and the archive are notified, which causes the study to be automatically removed from any list on a workstation where it might be a read candidate.

RESULTS

Implementation of this system provides a balanced workflow throughout the system while minimizing the need for costly high-speed network hardware. Additionally studies are read as soon as they are available by the next available radiologist. This workflow is enabled without the need for specific interaction by any of the radiologists on the network. By having the images available at the workstation in an organized worklist, this methodology increases the efficiency of the radiologist.

CONCLUSION

The implementation of this system enables a radiology department, or even a specialty group within a department, to gain the benefit of a distributed system as well as the benefits provided by a central-server architecture. This can be done very cost effectively with minimal configuration overhead and hardware requirements.

Cryptosporidium meleagridis from humans: molecular analysis and description of affected patients

OBJECTIVES

To genetically characterize an unusual genotype of Cryptosporidium from the stools of humans with diarrhoea and to identify risk factors in the affected patients.

METHODS

DNA was extracted from human faeces where Cryptosporidium oocysts were detected by light microscopy. Cryptosporidial gene fragments from six different loci were analysed by PCR alone, PCR/RFLP and by DNA sequencing. Oocysts were characterized by light and immunofluorescence microscopy and epidemiological data was collected from the affected patients.

RESULTS

Analysis of the Cryptosporidium oocyst wall protein (COWP) gene amplified from > 2000 human faecal samples identified 19 patients all of which produced an unusual RFLP profile. Subsequent DNA sequence analysis of this and an additional four genetic loci (including 18S rRNA sequences) confirmed these as a homogeneous group which was genetically distinct from Cryptosporidium parvum. The isolates were identified as Cryptosporidium meleagridis since the gene sequences were identical to those from this species recovered from birds. Conventional microscopy showed oocysts indistinguishable from C. parvum and reacted strongly with two different commercially available anti-oocyst monoclonal antibodies. None of the patients showed risk factors unusual for cryptosporidiosis; however, ten of the cases occurred during the summer/autumn, six had a history of foreign travel, four were co-infected with Giardia, two were HIV positive, and six were without identifiable immunocompromising factors.

CONCLUSIONS

This study further confirms that C. meleagridis, in addition to C. parvum, is involved in human disease. The study also highlights the lack of basic information on the host range of this genus of parasites, the complexity of the transmission routes involved in human cryptosporidiosis, and the value of molecular techniques in identify hitherto unrecognised differences in Cryptosporidium from human faeces.

Use of 5-bromo-4-chloro-3-indolyl-alpha-D-N-acetylneuraminic acid in a novel spot test To identify sialidase activity in vaginal swabs from women with bacterial vaginosis

The validity of measuring vaginal sialidase activity to identify bacterial vaginosis (BV) was determined by using 5-bromo-4-chloro-3-indolyl-alpha-D-N-acetylneuraminic acid in a near-patient test. The sensitivity and specificity of the test for prediction of BV were 95.6 and 96.3%, respectively. Positive and negative predictive values were 95.6 and 96.3%, respectively. This test may be an alternative to Gram staining.

Mucinase and sialidase activity of the vaginal microflora: implications for the pathogenesis of preterm labour

Evidence linking bacterial vaginosis (BV) to chorioamnionitis and spontaneous preterm birth is mounting. Successful treatment of BV could reduce the rate of late miscarriage and preterm birth. Mucinase and sialidase activity have been implicated in the pathogenesis of BV. This study extends the work of previous studies to investigate sialidase, other known mucin degrading enzymes and overall mucin degrading activity in samples of vaginal fluid from women with and without BV. Samples from 31 women were diagnosed for BV, and tested for enzyme activity using established assays. Activity was recorded in all samples. Significant increases in activity were detected in BV samples for sialidase using a mucin (BSM P<0.005) and serum type glycoprotein (AGP P<0.005) substrates, beta-galactosidase (P<0.001), and beta-N-acetylhexosaminidase (P<0.01). No significant increases in BV patients were detected in O-glycanase, proteinase, arylesterase, sulphatase or whole mucinase activities. These results support the hypothesis that certain BV-associated enzymes may detrimentally affect the mucosal barrier, permitting bacteria access to the uterus.

A large outbreak of cryptosporidiosis associated with a public water supply from a deep chalk borehole. Outbreak Investigation Team

Three hundred and forty-five confirmed cases were reported in a large waterborne outbreak of cryptosporidiosis in North Thames in the spring of 1997. The descriptive epidemiology, attack rates, a case control study, and the detection of oocysts in the water suggested strongly that the outbreak was associated with drinking unboiled tap water that originated from one deep chalk borehole. The 746,000 people living in the water distribution area were advised to boil their drinking water. Investigations did not reveal how oocysts entered the borehole. This is the first published report of a cryptosporidium outbreak caused by filtered borehole water and we believe it to be the largest outbreak due to groundwater to have been reported. Borehole supplies are regarded as relatively pure sources of water and this outbreak has implications for the future monitoring and treatment of drinking water extracted from boreholes.

Podocyte phenotypes as defined by expression and distribution of GLEPP1 in the developing glomerulus and in nephrotic glomeruli from MCD, CNF, and FSGS. A dedifferentiation hypothesis for the nephrotic syndrome

Glomerular epithelial protein 1 (GLEPP1) is a podocyte receptor membrane protein tyrosine phosphatase located on the apical cell membrane of visceral glomerular epithelial cell (VGEC) foot processes. Double label immunofluorescence, immunoelectron microscopy, and peroxidase immunohistochemistry were used to map the GLEPP1 distribution in the developing glomerulus and in minimal-change nephropathy (MCN), congenital nephrotic syndrome of the Finnish type, and focal-segmental glomerulosclerosis (FSGS). In MCN GLEPP1 was shifted away from the glomerular basement membrane on the apical cell membrane of effaced foot processes. These data are compatible with the previously suggested concept that MCN can be considered a form of dedifferentiation of the podocyte phenotype. Similarly, changes seen in congenital nephrotic syndrome of the Finnish type can be considered a consequence of failure to complete normal podocyte development. In FSGS glomeruli GLEPP1 was frequently absent from VGECs, even when no sclerosis was detectable in that glomerulus. Therefore, in FSGS, VGECs may lose GLEPP1, and this loss appears to occur in the absence of scarring and may, therefore, precede the scarring process. We speculate that a changed VGEC phenotype that does not express GLEPP1 might have properties similar to the early undifferentiated VGEC developmental phenotype. GLEPP1 distribution pattern and absence from glomeruli of individuals with nephrotic syndrome may, therefore, represent a useful phenotypic marker.

Glomerular epithelial protein 1 and podocalyxin-like protein 1 in inflammatory glomerular disease (crescentic nephritis) in rabbit and man

The podocyte is the cell responsible in large part for maintaining the glomerular filtration barrier. Glomerular epithelial protein 1 (GLEPP1) is a novel receptor-like transmembrane protein tyrosine phosphatase present on the apical surface of podocyte foot processes. Podocalyxin-like protein 1 (PCLP1) is a transmembrane sialoglycoprotein which is also present on the foot process apical surface as well as on the surface of endothelial cells. GLEPP1 and PCLP1 are thought to play a role in regulating the structure and function of podocyte foot processes. Glomerular injury affecting the podocyte is likely to be reflected by changes in these proteins. GLEPP1 distribution in human renal biopsy with inflammatory glomerular disease and crescent formation was examined by immunocytochemistry. A model of inflammatory glomerular injury induced by guinea pig anti-rabbit basement membrane (anti-GBM) antibody was used to examine the distribution and amount of GLEPP1 and PCLP1 mRNA and protein. A biopsy study was done to determine whether the extent of GLEPP1 depletion from glomeruli at early time points (Day 7) would predict the severity of crescent formation at Day 30. Glomeruli from human renal biopsies with crescentic nephritis showed focal to diffuse disappearance of GLEPP1 protein. No GLEPP1 was present within the cellular crescent. By Day 4 of the rabbit anti-GBM model, before cellular crescents had formed, GLEPP1 protein was reduced from 127 +/- 28 X 10(7) to 30 +/- 5 X 10(7) molecules per glomerulus (p < 0.001), and GLEPP1 mRNA was reduced by 62% (p < 0.05). In contrast, at this time there was no significant reduction of PCLP1 protein from the normal number of 309 X 10(9) molecules per glomerulus and the PCLP1 mRNA level had not decreased. At Day 4, podocyte foot processes were effaced and proteinuria was present. Glomerular culture supernatants from Day 4 rabbits caused a reduction in GLEPP1 but not PCLP1 protein expression by cultured normal glomeruli, showing that a soluble factor was produced at Day 4 which reduced the number of GLEPP1 molecules in glomeruli. There was no detectable proteolysis of GLEPP1 or PCLP1 in glomeruli and no increase in GLEPP1 or PCLP1 excretion in urine. Therefore, the reduction in glomerular GLEPP1 was associated with reduced synthetic capacity. The proportion of glomeruli with reduced GLEPP1 at Day 7 of the model was significantly associated with the percent of glomeruli which had formed crescents at Day 30 (r = 0.86, p < 0.0001). GLEPP1 appears to be a sensitive indicator of glomerular injury during inflammation in man and in the rabbit model. A reduction in amount of GLEPP1 is associated with worse outcome for the glomerulus.

Fibronectin is the major fibroblast chemoattractant in rabbit anti-glomerular basement membrane disease

The mechanism for fibroblast recruitment in renal fibrosis due to anti-glomerular basement membrane (anti-GBM) disease is unknown. Since fibroblast recruitment can occur via chemotaxis, assessment of the possible production of fibroblast chemotactic activity by affected renal tissue and its identification could provide important clues. Anti-GBM disease was induced by injection of guinea pig anti-rabbit GBM immunoglobulin G into rabbits previously sensitized to guinea pig immunoglobulin G. On days 4, 7, and 14 after induction, renal tissue was harvested and glomeruli isolated. Overnight serum-free conditioned media from whole cortex and glomeruli were prepared and assayed for fibroblast chemotactic activity. The results show low level activity in both conditioned media from control animals. In contrast, conditioned media from anti-GBM-treated animals at all time points showed significantly elevated fibroblast chemotactic activity peaking on day 4 with subsequent reduction thereafter. The magnitude of increase in cortical conditioned media was significantly higher than that for glomerular conditioned media, suggesting that most of the activity was derived from extraglomerular sources. Gel filtration analysis revealed the activity to be heterogeneous, consisting of at least four major species with estimated molecular weights ranging from 10 to > 100 kd. Acidification of conditioned media failed to increase chemotactic activity significantly, whereas protease digestion abolished it. Treatment of conditioned media with antifibronectin inhibited > 85% of the chemotactic activity, whereas antibodies to platelet-derived growth factor and transforming growth factor-beta did not have a significant effect. These findings taken together suggest that fibronectin-derived peptides represent the predominant fibroblast chemoattractant produced by renal cortex in anti-GBM disease.

Vascular adventitial cell expression of collagen I messenger ribonucleic acid in anti-glomerular basement membrane antibody-induced crescentic nephritis in the rabbit. A cellular source for interstitial collagen synthesis in inflammatory renal disease

BACKGROUND

Scarring in the interstitial compartment of the renal cortex heralds a poor prognosis in many forms of renal injury, however, the mechanism through which glomerular inflammation leads to interstitial scarring is not understood. In a model of anti-GBM disease in the rabbit, development of crescentic glomerulonephritis is associated with marked interstitial fibrosis and decreased renal function. We previously demonstrated that collagen accumulation in the model was preceded by increases in collagen I and IV mRNA and that these changes were primarily extraglomerular at early time points when inflammation was predominantly intraglomerular. In order to identify the cellular origins of extraglomerular collagen synthesis in this model, in situ hybridization using an alpha 2(I) procollagen probe was performed.

EXPERIMENTAL DESIGN

A 602 bp rabbit alpha 2(I) procollagen cDNA was cloned using a PCR strategy and sequenced. The nucleotide sequence of the coding region was 94% identical with the human alpha 2(I) procollagen sequence. Northern blots were performed to define conditions of specific hybridization of the anti-sense riboprobe. Tissue sections from normal rabbit kidneys and from kidneys 4, 5, 7, 10 and 14 days after injection of anti-GBM antibody were hybridized with 35S-labeled sense and anti-sense riboprobes. Cells containing alpha 2(I) mRNA were identified by autoradiography and mRNA abundance was quantitated by grain density.

RESULTS

No specific hybridization was detected with the sense probe at any time. alpha 2(I) mRNA was undetectable with the anti-sense probe in normal kidney sections. In contrast, the anti-sense probe hybridized specifically at all time points after induction of anti-GBM disease. In agreement with previous filter hybridization studies, on day 4, when inflammation was predominantly intraglomerular, cells in the periarterial adventitial compartment of renal cortex hybridized strongly. At later time points, labeling was also present in the interstitial spaces, the periglomerular region, in Bowman's space and in the glomerular tuft itself.

CONCLUSIONS

We conclude that perivascular adventitial cells are among the first to respond to glomerular inflammation and represent a pool of cells that subsequently contribute to interstitial and glomerular scarring.

Urine transforming growth factor-beta activity is related to the degree of scarring in crescentic nephritis in the rabbit

Crescentic nephritis was induced in rabbits by injection of antirabbit glomerular basement membrane (GBM) antibodies. Urine samples were obtained by catheterization and assayed for transforming growth factor-beta (TGF-beta) activity. On day 31, all animals were sacrificed for evaluation of renal cortical histopathology and collagen content. The results show that control rabbit urine contains measurable amounts of TGF-beta. Urine TGF-beta activity was expressed in relation to urine creatinine concentration to correct for variation in urine concentration. When expressed in this manner, urine TGF-beta activity increased from day 2 onwards, peaked on day 7 and returned to normal levels after day 14. This time course is identical to that previously seen for the cortical and glomerular production of TGF-beta in the same model. Furthermore, when the normalized TGF-beta values for each animal were compared to their respective fibrosis parameters on day 31, significant correlations were observed for the values of urine TGF-beta activities on day 7 and all indices of fibrosis. These results suggest that measurements of urine TGF-beta activity at certain critical stages of disease could be useful in predicting the progression to end-stage renal disease with fibrosis and might serve as a helpful noninvasive adjunct in monitoring response to therapy.

Analysis of T cells and major histocompatibility complex class I and class II mRNA and protein content and distribution in antiglomerular basement membrane disease in the rabbit

The major interacting components of the immune system, major histocompatibility complex (MHC) class I and class II proteins and T cells were analyzed in a model of anti-GBM (glomerular basement membrane) disease in the rabbit that progresses to develop cellular crescents and glomerular and interstitial fibrosis. Class I and II mRNA and protein were measured in isolated glomeruli and whole renal cortex using cDNA probes and monoclonal antibodies. The distribution of T cells and class I and II proteins was assessed by immunofluorescence. Normal glomeruli contained no T cells and were class II negative. By day 4, glomeruli contained MHC class I and II mRNA and protein and class II positive T cells. Although some animals had T cells in the periglomerular area, these cells were class II negative. By day 7 periglomerular T cells were largely class II positive (activated) and there was increased MHC class I and II mRNA and protein in whole renal cortex. Later T cells accumulated in the tubulo-interstitial compartment, which became diffusely positive for MHC classes I and II, but to a variable extent in different animals. Those with high class II mRNA expression also had detectable T cell antigen receptor mRNA by Northern analysis. The authors conclude 1) in this model there was a close association between mRNA abundance and protein expression for both MHC classes I and II in glomeruli and renal cortex as a whole; 2) in this model of glomerular injury there are three phases of activation. The first phase takes place in the glomerulus and is associated with accumulation of activated T cells and MHC class I and II protein in the glomerulus. Phase 2 is associated with the accumulation of periglomerular T cells and their becoming class II positive. There is subsequent dissemination (phase 3) of activated T cells and accumulation of class I and II mRNA and protein throughout the interstitial compartment. This spacial progression of glomerulocentric inflammation is likely associated with degree of injury and permanent loss of renal function.

Fibronectin mRNA and protein accumulation, distribution, and breakdown in rabbit anti-glomerular basement membrane disease

Fibronectin is a multifunctional matrix protein which by immunofluorescence appears to be present in increased amounts during glomerular injury. To examine fibronectin metabolism in glomerular injury, an anti-glomerular basement membrane model that progresses to severe glomerular crescent formation, glomerulosclerosis, and interstitial fibrosis was used. Fibronectin was purified from rabbit plasma, and a monoclonal antibody raised against rabbit fibronectin was used for immunolocalization and quantitation of fibronectin protein. RNA and protein were extracted from isolated glomeruli and whole renal cortex at various times during progression of disease. At day 4, there was a 2.5-fold increase in fibronectin protein which by immunofluorescence appeared to be in the glomerular mesangial area. There was no increase in glomerular fibronectin mRNA at this time. This discrepancy is consistent with the conclusion that, at this early time point, the increased glomerular fibronectin comes predominantly from plasma. By day 7, glomerular fibronectin mRNA and extractable fibronectin protein were increased in association with bright immunofluorescence along the inner aspect of Bowman's capsule where early crescents were forming. Similarly, at day 14, crescents stained very brightly for fibronectin. These results are consistent with the conclusion that, at later time points, fibronectin is synthesized in glomeruli in association with cell division and crescent formation. Degradation of fibronectin in glomerular and cortical extracts was demonstrated under normal and nephritic conditions by finding fibronectin proteolytic fragmentation by Western blot.(ABSTRACT TRUNCATED AT 250 WORDS)

Transforming growth factor-beta production in anti-glomerular basement membrane disease in the rabbit

The purpose of this study was to assay for the presence of collagen synthesis stimulatory activity in the kidney during immune-induced renal injury that results in severe fibrosis in both glomerular and interstitial compartments. A model of antiglomerular basement (anti-GBM) disease in the rabbit was induced on day 0 by the injection of anti-GBM antibody and renal cortex tissues were then sampled at various time points. Only conditioned media prepared from diseased renal cortical samples showed collagen synthesis stimulatory activity when tested on rabbit mesangial cells. The activity had an estimated molecular weight range of 16 to 25 kd and was neutralized by antibody to transforming growth factor-beta (TGF-beta). A standard assay for TGF-beta using a mink lung epithelial cell line confirmed the increase in TGF-beta activity in conditioned media of diseased cortex from day 7 and day 14 animals, which was not significantly activated by previous acidification. This suggests that most of the TGF-beta present in renal conditioned media was in the active form. The increase in renal cortical secretion of active TGF-beta was accompanied by increases in renal cortical TGF-beta mRNA content on days 4 and 7 after induction, with subsequent return to control levels. A similar increase in TGF-beta activity was present in nonacidified conditioned media of purified glomeruli from diseased days 7 and 14 animals, which was also accompanied by significant increases in TGF-beta mRNA. However with acidification no significant differences were noted between control and diseased samples, suggesting the presence of substantial latent TGF-beta activity in control glomerular conditioned media. These same control-conditioned media contained inhibitor activity for added exogenous TGF-beta. These results support the conclusion that the association between increased TGF-beta secretion and increased renal cortical collagen synthesis in this model is consistent with a role for this cytokine in directing fibrogenesis in the kidney.

Monocyte chemotactic protein gene expression by cytokine-treated human fibroblasts and endothelial cells

A number of cytokines are active during the evolution of an inflammatory response, including tumor necrosis factor-alpha, interleukin-1, and novel chemotactic cytokines. This latter group of mediators belong to supergene families of inflammatory signals that play a key role in the selective recruitment of immune cells. In this presentation, we present data demonstrating, for the first time, endothelial cell expression of monocyte chemotactic protein (MCP) mRNA induced by LPS, interleukin-1 or tumor necrosis factor. Human fibroblasts were also found to express monocyte chemotactic factor mRNA in response to interleukin-1 or tumor necrosis factor, but LPS was not effective. In addition, neither primary cultures expressed MCP in response to interleukin-6. These studies demonstrate that non-immune "bystander" cells can play an active role in the recruitment of inflammatory cells via the production of novel chemotactic cytokines.

Comparative ability of human monocytes and neutrophils to degrade glomerular basement membrane in vitro

We have compared the ability of human peripheral blood monocytes and neutrophils to degrade glomerular basement membrane (GBM) in vitro. When isolated cells were incubated with GBM containing anti-GBM immune complexes, both neutrophils and monocytes adhered and spread on the surface of the GBM, underwent a respiratory burst and released lysosomal enzymes into the medium. With neutrophils, this resulted in rapid degradation of the GBM, measured both as solubilization of collagenous and noncollagenous protein. In contrast, monocytes degraded GBM very slowly, with a slight increase in the rate of hydroxyproline solubilization after approximately 24 hours incubation. Degradation of GBM by neutrophils was predominantly due to the action of serine proteinases, whereas inhibition of monocyte-mediated hydroxyproline release required both phenylmethylsulfonyl fluoride and o-phenanthroline, suggesting some synergy between serine and metalloproteinases. The results indicate that neutrophils are more able to degrade GBM components than are monocytes, and suggest that they may be capable of greater damage to the GBM in vivo, mostly due to their higher proteolytic capacity.

Glomerular basement membrane-containing immune complexes stimulate tumor necrosis factor and interleukin-1 production by human monocytes

The ability of human peripheral blood monocytes to produce tumor necrosis factor (TNF) and interleukin-1 (IL-1) in an in vitro model of immune complex-mediated glomerulonephritis was investigated. When isolated monocytes were incubated with human glomerular basement membrane (GBM) containing anti-GBM immune complexes, both TNF and IL-1 were produced and secreted into the medium. The time course of secretion differed, with IL-1 production being maximal after approximately 8 hours, whereas TNF levels continued to rise for 30 hours. The activities of the monocyte-derived TNF and IL-1 were inhibitable by specific antibodies. No effect was seen when monocytes were incubated separately with either GBM alone or anti-GBM IgG. The levels of TNF and IL-1 released were comparable with those induced by high concentrations of LPS, indicating that production was close to the maximal levels reported for these cells. High levels of TNF and IL-1 also were produced in response to soluble immune complexes. The results show that monocytes can produce significant levels of TNF and IL-1 in response to both surface-bound and soluble immune complexes and provide support for the participation of these monokines in glomerulonephritis.

Lipid microvesicles and their association with procoagulant activity in urine and glomeruli of rabbits with nephrotoxic nephritis

The procoagulant activity (PCA) in urine of rabbits with nephrotoxic nephritis was characterized. Most of the PCA in urine was pelleted by centrifugation at 50,000 X g but was not pelleted together with cells and casts at 1,000 X g. PCA appeared in the void volume of a Sepharose 4B column but would not pass through a 0.2-micron filter. Ultrastructural studies using both transmission and scanning electron microscopy showed that urine PCA was associated with lipid vesicles 0.1 to 1-micron in diameter. These vesicular structures were shown to promote fibrin formation from recalcified plasma on a 0.2-micron filter surface. This microvesicular PCA was mostly Factor VII-like as judged by clotting assay using human factor-deficient plasmas. Aggregates of vesicles were present in urine as granular casts. Ultrastructural studies of rabbit kidney showed similar vesicular structures in the proximal tubular lumen and budding from glomerular epithelial cells. Fibrin was seen adjacent to both glomerular endothelial cells and epithelial cells in association with vesicular structures. We conclude that microvesicles in urine carry a procoagulant signal which is tissue factor/Factor VII-like. We speculate that these vesicles may come from the glomerulus by budding off from glomerular epithelial cells, or macrophages.

Dietary supplementation of undernourished rats with soy or safflower oil: effects on myelin polyunsaturated fatty acids

Undernourished suckling rats were administered, by gastric intubation, either soy oil (which is rich in both linoleic and linolenic acids) or safflower oil (which is rich in linoleic acid but deficient in linolenic acid) to determine (1) if dietary supplementation would offset the hypomyelination characteristic of the undernourished, developing brain and (2) to compare myelin fatty acids in normal, undernourished, and oil-supplemented rats. Myelin recovery was not increased by supplementation with either oil. The proportions of C22:4 and C22:6 fatty acids were reduced in myelin of the undernourished rats. Undernourished rats supplemented with either soy or safflower oil had higher than normal proportions of polyunsaturated fatty acids (C20:4 and C22:6). The triene-tetraene ratio in the oil-supplemented rats was lower than in normal controls, indicating that the oil-supplemented rats were not deficient in essential fatty acids. No significant differences were observed between the oil-supplemented groups.

Constant intrarenal infusion of PGE1 into a canine renal transplant using a totally implantable pump

A method was devised whereby PGE1 could be administered to a canine renal transplant recipient on a chronic basis. PGE1 was stored in the reservoir of an implantable pump and delivered continuously in high doses directly into the renal transplant artery. In the model studied a contralateral untreated transplant from the same donor served as a control. Sequential renal scans were used to study the effect of intraarterial PGE1 on the rejection process. Continuous delivery of PGE1 into the renal transplant artery did not prevent allograft failure under these conditions; blood flow diminished similarly in both PGE1-treated and untreated transplants. There were, however, striking differences in the histologic appearance of treated and untreated transplants. PGE1 perfusion resulted in the appearance of large numbers of polymorphonuclear leukocytes but few lymphocytes. In the untreated control allograft, however, the findings were typical of lymphocyte-mediated acute rejection. The distinctive differences noted histologically suggested that the local administration of PGE1 influenced the mechanism by which graft failure occurred. The ability to manipulate cell populations infiltrating an allograft represents a potentially important means for modifying the immune response.

Early undernutrition and [3H]gamma-aminobutyric acid binding in rat brain

The effect of early undernutrition and dietary rehabilitation on [3H]gamma-aminobutyric acid ([3H]GABA) binding in rat brain cerebral cortex and hippocampus was examined. Undernourished animals were obtained by exposing their mothers to a protein-deficient diet during both gestation and lactation. Saturation analysis of [3H]GABA binding in the cerebral cortex and hippocampus revealed high- and low-affinity components in the undernourished group, whereas control animals possessed only a low-affinity site. The concentration of low-affinity binding sites was greater in the undernourished animals. Rehabilitation of undernourished animals completely abolished the binding site differences. Treatment of brain membranes with Triton X-100 yielded two binding components in both the undernourished and control animals, although the concentration of lower affinity sites was still greater in the undernourished group. Neither the efficacy nor the potency of GABA to activate benzodiazepine binding in cerebral cortex was modified by undernutrition. These data suggest that early undernourishment modifies the characteristics of [3H]GABA binding, perhaps by reducing the brain content of endogenous inhibitors of the higher affinity binding site. The lack of effect on GABA-activated benzodiazepine binding suggests the possibility that neither the high- nor the low-affinity GABA binding sites are coupled to this receptor component.