Universal and Language-Specific Connected Speech Characteristics of Bilingual Speakers With Alzheimer's Disease: Insights From Case Studies of Structurally Distinct Languages

PURPOSE

Connected speech analysis has been effectively utilized for the diagnosis and disease monitoring of individuals with Alzheimer's disease (AD). Existing research has been conducted mostly in monolingual English speakers with a noticeable lack of evidence from bilinguals and non-English speakers, particularly in non-European languages. Using a case study approach, we characterized connected speech profiles of two Bengali-English bilingual speakers with AD to determine the universal features of language impairments in both languages, identify language-specific differences between the languages, and explore language impairment characteristics of the participants with AD in relation to their bilingual language experience.

METHOD

Participants included two Bengali-English bilingual speakers with AD and a group of age-, gender-, education-, and language-matched neurologically healthy controls. Connected speech samples were collected in first language (L1; Bengali) and second language (L2; English) using a novel storytelling task (i.e., Frog, Where Are You?). These samples were analyzed using an augmented quantitative production analysis and correct information unit analyses for productivity, fluency, syntactic and morphosyntactic features, and lexical and semantic characteristics.

RESULTS

Irrespective of the language, AD impacted speech productivity (speech rate and fluency) and semantic characteristics in both languages. Unique language-specific differences were noted on syntactic measures (reduced sentence length in Bengali), lexical distribution (fewer pronouns and absence of reduplication in Bengali), and inflectional properties (no difficulties with noun or verb inflections in Bengali). Among the two participants with AD, the individual who showed lower proficiency and usage in L2 (English) demonstrated reduced syntactic complexity and morphosyntactic richness in English.

CONCLUSIONS

Evidence from these case studies suggests that language impairment features in AD are not universal across languages, particularly in comparison to impairments typically associated with language breakdowns in English. This study underscores the importance of establishing connected speech profiles in AD for non-English-speaking populations, especially for structurally different languages. This would in turn lead to the development of language-specific markers that can facilitate early detection of language deterioration and aid in improving diagnosis of AD in individuals belonging to underserved linguistically diverse populations.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25412458.

Ethical issues in clinical neuropsychology: International diversity perspectives

OBJECTIVE

Much of the information about the ethical practice of clinical neuropsychology has focused on North America. Additionally, of the scholarly publications on the intersection of ethical issues and cultural diversity practices in neuropsychology, most have focused on North America. The extent to which practitioners in other parts of the world are aware of, and find useful, such information is largely unknown. Similarly, the extent to which North American neuropsychologists are familiar with ethical issues and challenges encountered around the world is unknown. The purpose of this article is to advance the discussion of ethical issues in clinical neuropsychology from an international diversity perspective.

METHOD

The article presents, via a panel interview format, the thoughts and experiences of a small sample of neuropsychologists who represent all continents except North America (and Antarctica).

RESULTS

Neuropsychologists across continents share an ethical commitment to providing services that are beneficial, and not harmful, to the recipients of the services. Professional competence is at the heart of such services.

CONCLUSIONS

Through continued and expanded dialogue about ethical issues with neuropsychology colleagues around the world, the potential exists for improvement in the provision of effective and compassionate care in our own towns.

Importance of Task Selection for Connected Speech Analysis in Patients with Alzheimer’s Disease from an Ethnically Diverse Sample

Features of linguistic impairment in Alzheimer’s disease (AD) are primarily derived from English-speaking patients. Little is known regarding such deficits in linguistically diverse speakers with AD. We aimed to detail linguistic profiles (speech rate, dysfluencies, syntactic, lexical, morphological, semantics) from two connected speech tasks–Frog Story and picture description–in Bengali-speaking AD patients. The Frog Story detected group differences on all six linguistic levels, compared to only three with picture description. Critically, Frog Story captured the language-specific differences between the groups. Careful consideration should be given to the choice of connected speech tasks for dementia diagnosis in linguistically diverse populations.

Examination of the validity of the 'Papadum test': an alternative to the clock drawing test for people with low levels of education

Objectives: The clock drawing test (CDT) is a widely used cognitive screening test. However, CDT performance is affected by education. This study examined an alternative, the Papadum test, designed for people with low levels of education/literacy. The association between education and test performance, correlation between CDT and Papadum test, and diagnostic accuracy of both CDT and Papadum tests were examined. Method: 89 healthy literate adults and 59 literate adults (all Bengali speaking) with a diagnosis of mild-moderate dementia from hospitals in Kolkata, India undertook the CDT and the Papadum test. Results: Education had a significant association with the CDT but not with the Papadum test. Across the whole sample there was a significant correlation between CDT and Papadum, but not within separate groups of healthy controls and patients. Diagnostic accuracy for the Papadum test was similar to that for CDT. Conclusions: Results highlight the strong influence that education has on CDT performance indicating that it is not suitable for those with low levels of literacy. The Papadum test could provide a viable alternative as a screening tool to the CDT for use with people who are illiterate or have low levels of education. Further validation studies are required.

Connected Speech Characteristics of Bengali Speakers With Alzheimer's Disease: Evidence for Language-Specific Diagnostic Markers

Background and aim: Speech and language characteristics of connected speech provide a valuable tool for identifying, diagnosing and monitoring progression in Alzheimer's Disease (AD). Our knowledge of linguistic features of connected speech in AD is primarily derived from English speakers; very little is known regarding patterns of linguistic deficits in speakers of other languages, such as Bengali. Bengali is a highly inflected pro-drop language from the Indo-Aryan language family. It is the seventh most spoken language in the world, yet to date, no studies have investigated the profile of linguistic impairments in Bengali speakers with AD. The aim of this study was to characterize connected speech production and identify the linguistic features affected in Bengali speakers with AD. Methods: Participants were six Bengali speaking AD patients and eight matched controls from the urban metropolis, Kolkata, India. Narrative samples were elicited in Bengali using the Frog Story. Samples were analyzed using the Quantitative Production Analysis and the Correct Information Unit analyses to quantify six different aspects of speech production: speech rate, structural and syntactic measures, lexical measures, morphological and inflectional measures, semantic measures and measure of spontaneity and fluency disruptions. Results and conclusions: In line with the extant literature from English speakers, the Bengali AD participants demonstrated decreased speech rate, simplicity of sentence forms and structures, and reduced semantic content. Critically, differences with English speakers' literature emerged in the domains of Bengali specific linguistic features, such as the pro-drop nature of Bengali and its inflectional properties of nominal and verbal systems. Bengali AD participants produced fewer pronouns, which is in direct contrast with the overuse of pronouns by English AD participants. No obvious difficulty in producing nominal and verbal inflections was evident. However, differences in the type of noun inflections were evident; these were characterized by simpler inflectional features used by AD speakers. This study represents the first of its kind to characterize connected speech production in Bengali AD participants and is a significant step forward toward the development of language-specific clinical markers in AD. It also provides a framework for cross-linguistic comparisons across structurally distinct and under-explored languages.

Validation of Indian Council of Medical Research Neurocognitive Tool Box in Diagnosis of Mild Cognitive Impairment in India: Lessons from a Harmonization Process in a Linguistically Diverse Society

BACKGROUND/AIMS

In a linguistically diverse country such as India, challenges remain with regard to diagnosis of early cognitive decline among the elderly, with no prior attempts made to simultaneously validate a comprehensive battery of tests across domains in multiple languages. This study aimed to determine the utility of the Indian Council of Medical Research-Neurocognitive Tool Box (ICMR-NCTB) in the diagnosis of mild cognitive impairment (MCI) and its vascular subtype (VaMCI) in 5 Indian languages.

METHODS

Literate subjects from 5 centers across the country were recruited using a uniform process, and all subjects were classified based on clinical evaluations and a gold standard test protocol into normal cognition, MCI, and VaMCI. Following adaptation and harmonization of the ICMR-NCTB across 5 different Indian languages into a composite Z score, its test performance against standards, including sensitivity and specificity of the instrument as well as of its subcomponents in diagnosis of MCI, was evaluated in age and education unmatched and matched groups.

RESULTS

Variability in sensitivity-specificity estimates was noted between languages when a total of 991 controls and 205 patients with MCI (157 MCI and 48 VaMCI) were compared due to a significant impact of age, education, and language. Data from a total of 506 controls, 144 patients with MCI, and 46 patients with VaMCI who were age- and education-matched were compared. Post hoc analysis after correction for multiple comparisons revealed better performance in controls relative to all-cause MCI. An optimum composite Z-score of -0.541 achieved a sensitivity of 81.1% and a specificity of 88.8% for diagnosis of all-cause MCI, with a high specificity for diagnosis of VaMCI. Using combinations of multiple-domain 2 test subcomponents retained a sensitivity and specificity of >80% for diagnosis of MCI.

CONCLUSIONS

The ICMR-NCTB is a "first of its kind" approach at harmonizing neuropsychological tests across 5 Indian languages for the diagnosis of MCI due to vascular and other etiologies. Utilizing multiple-domain subcomponents also retains the validity of this instrument, making it a valuable tool in MCI research in multilingual settings.

Bilingualism and Its Implications for Neuropsychological Evaluation

OBJECTIVE

In the background of a large population of bilinguals globally, the study aimed to develop standards of neuropsychological testing in the context of bilingualism. Because bilingualism is known to affect cognitive processes, bilinguals and monolinguals were compared on their performance on cognitive tests, to investigate the possibility of the need for separate normative data for the two groups.

METHOD

A comprehensive neuropsychological test battery, standardized across five Indian languages: the Indian Council of Medical Research-Neuro Cognitive Tool Box (ICMR-NCTB) was administered to 530 participants (267 monolingual and 263 bilinguals matched for age and education). A systematic method of testing cognition in bilinguals was developed; to identify the appropriate language for testing, ensure language proficiency of examiner, and to interpret the bilingual responses. Additionally, the performance of bilinguals on the ICMR-NCTB was compared with monolinguals.

RESULTS

Cognitive testing in the bilingual context was performed in the most proficient language of the participants, by examiners well versed with the language. Results from the language-based tests suggested that the frequent occurrence of borrowed- and language-mixed words required consideration while scoring. The reported bilingual effect on cognitive processes did not reflect as differences in the performance between bilinguals and monolinguals.

CONCLUSIONS

Observations from the study provide robust recommendations for neuropsychological testing in the context of bilingualism. Results indicate that separate normative data may not be required for bilinguals and monolinguals. The study will be relevant and provide a reference framework to address similar issues in the large population of bilinguals in other societies.

A Screening Tool to Detect Stroke Aphasia: Adaptation of Frenchay Aphasia Screening Test (FAST) to the Indian Context

Background:

Aphasia is a common consequence of stroke. To optimize recovery, it becomes critical as there are early identification and treatment of language deficits. The rising burden of stroke aphasia and lack of screening tools in the Indian context necessitates the need for a screening tool.

Objective:

We aimed to adapt and validate the Frenchay Aphasia Screening Test (FAST) to the Indian context in two widely spoken Indian languages, Telugu and Kannada, for the literate and illiterate population.

Methods:

A systematic process of adaptation and culturally appropriate modifications of the original FAST were done in 116 healthy controls and 115 patients. The validity of the adapted test was established.

Results:

The optimum cut-off values for detecting aphasia in our sample ranged from 25 to 25.5 (literate) and 13.5 to 15.5 (illiterate) with high sensitivity and specificity. There was also a significant correlation between aphasia scores for adapted FAST and the Western Aphasia Battery (WAB), establishing good convergent validity.

Discussion:

Results of the adaptation and validation of two Indian versions of FAST, suggest that it is an easy-to-use screening measure for detecting stroke-related language disabilities. The psychometric properties of the Indian version of FAST met the standardised requirements for adaptation and validation.

Conclusions:

The Indian version of FAST was found to be a reliable and valid bedside screening tool for aphasia in stroke patients. We aim that this study will facilitate the use of the test across other Indian languages and a large clinical population in the future.

Distinct performance profiles on the Brixton test in frontotemporal dementia

The Brixton Spatial Anticipation Test is a well-established test of executive function that evaluates the capacity to abstract, follow, and switch rules. There has been remarkably little systematic analysis of Brixton test performance in the prototypical neurodegenerative disorder of the frontal lobes: behavioural variant frontotemporal dementia (bvFTD) or evaluation of the test's ability to distinguish frontal from temporal lobe degenerative disease. We carried out a quantitative and qualitative analysis of Brixton performance in 76 patients with bvFTD and 34 with semantic dementia (SD) associated with temporal lobe degeneration. The groups were matched for demographic variables and illness duration. The bvFTD group performed significantly more poorly (U = 348, p < .0001, r = .58), 53% of patients scoring in the poor-impaired range compared with 6% of SD patients. Whereas bvFTD patients showed problems in rule acquisition and switching, SD patients did not, despite their impaired conceptual knowledge. Error analysis revealed more frequent perseverative errors in bvFTD, particularly responses unconnected to the stimulus, as well as random responses. Stimulus-bound errors were rare. Within the bvFTD group, there was variation in performance profile, which could not be explained by demographic, neurological, or genetic factors. The findings demonstrate sensitivity and specificity of the Brixton test in identifying frontal lobe degenerative disease and highlight the clinical value of qualitative analysis of test performance. From a theoretical perspective, the findings provide evidence that semantic knowledge and the capacity to acquire rules are dissociable. Moreover, they exemplify the separable functional contributions to executive performance.

IKBKE activity enhances AR levels in advanced prostate cancer via modulation of the Hippo pathway

Resistance to androgen receptor (AR) targeting therapeutics in prostate cancer (PC) is a significant clinical problem. Mechanisms by which this is accomplished include AR amplification and expression of AR splice variants, demonstrating that AR remains a key therapeutic target in advanced disease. For the first time we show that IKBKE drives AR signalling in advanced PC. Significant inhibition of AR regulated gene expression was observed upon siRNA-mediated IKBKE depletion or pharmacological inhibition due to inhibited AR gene expression in multiple cell line models including a LNCaP derivative cell line resistant to the anti-androgen, enzalutamide (LNCaP-EnzR). Phenotypically, this resulted in significant inhibition of proliferation, migration and colony forming ability suggesting that targeting IKBKE could circumvent resistance to AR targeting therapies. Indeed, pharmacological inhibition in the CWR22Rv1 xenograft mouse model reduced tumour size and enhanced survival. Critically, this was validated in patient-derived explants where enzymatic inactivation of IKBKE reduced cell proliferation and AR expression. Mechanistically, we provide evidence that IKBKE regulates AR levels via Hippo pathway inhibition to reduce c-MYC levels at cis-regulatory elements within the AR gene. Thus, IKBKE is a therapeutic target in advanced PC suggesting repurposing of clinically tested IKBKE inhibitors could be beneficial to castrate resistant PC patients.

The In Vitro Anti-Diabetic Activity of Lime Peels (Citrus amblycarpa (Hassk.) Ochse)

There are various potential natural anti-diabetic drugs; one of them is lime peel or Citrus amblycarpa. This study was aimed to explore the anti-diabetic activity and phytochemical content of lime peels. This study was an experimental study that used the post-test only control group design. The lime peels that were collected from the Berastagi fruit market in Medan, North Sumatera were extracted using 70% ethanol by maceration methods. The phytochemical screening identified the presence of phenolic, steroid/triterpenoid, terpenoid, saponin, flavonoid, tannin, and alkaloid. Meanwhile, the anti-diabetic activity of lime peels was evaluate using the α-glucosidase enzyme that was gotten from Saccharomyces cerevisiae by α-glucosidase enzyme inhibition methods. Percent of inhibition was express as Mean ± SD and analyzed by One Way ANOVA, Tukey HSD Post Hoc Test, and followed by linear regression. The result of this study showed that there is a significant difference in percentage inhibition α-glucosidase enzyme in each concentration, and it had an IC50 Value amount of 125.93 ± 9.14 µg/mL. The phytochemical content of the lime peels was flavonoid, phenol, steroid/triterpenoid, and alkaloid. Hence, the lime peel has anti-diabetic activity by inhibition of the α-glucosidase enzyme.

Drug-sensitive FGFR3 mutations in lung adenocarcinoma

BACKGROUND

Lung cancer is the leading cause of cancer-related deaths across the world. In this study, we present therapeutically relevant genetic alterations in lung adenocarcinoma of Indian origin.

MATERIALS AND METHODS

Forty-five primary lung adenocarcinoma tumors were sequenced for 676 amplicons using RainDance cancer panel at an average coverage of 1500 × (reads per million mapped reads). To validate the findings, 49 mutations across 23 genes were genotyped in an additional set of 363 primary lung adenocarcinoma tumors using mass spectrometry. NIH/3T3 cells over expressing mutant and wild-type FGFR3 constructs were characterized for anchorage independent growth, constitutive activation, tumor formation and sensitivity to FGFR inhibitors using in vitro and xenograft mouse models.

RESULTS

We present the first spectrum of actionable alterations in lung adenocarcinoma tumors of Indian origin, and shows that mutations of FGFR3 are present in 20 of 363 (5.5%) patients. These FGFR3 mutations are constitutively active and oncogenic when ectopically expressed in NIH/3T3 cells and using a xenograft model in NOD/SCID mice. Inhibition of FGFR3 kinase activity inhibits transformation of NIH/3T3 overexpressing FGFR3 constructs and growth of tumors driven by FGFR3 in the xenograft models. The reduction in tumor size in the mouse is paralleled by a reduction in the amounts of phospho-ERK, validating the in vitro findings. Interestingly, the FGFR3 mutations are significantly higher in a proportion of younger patients and show a trend toward better overall survival, compared with patients lacking actionable alterations or those harboring KRAS mutations.

CONCLUSION

We present the first actionable mutation spectrum in Indian lung cancer genome. These findings implicate FGFR3 as a novel therapeutic in lung adenocarcinoma.

A prospective comparative clinical study of peripheral blood counts and indices in patients with primary brain tumors

BACKGROUND

Elevation of the neutrophil to lymphocyte ratio (NLR) has been shown to be an indicator of poor prognosis in many malignancies including recurrent glioblastoma multiforme.

OBJECTIVES

This study was aimed at assessing if the NLR and other leukocyte counts and indices were deranged in treatment-naïve patients with primary brain tumors when compared with an age-matched healthy control group.

MATERIALS AND METHODS

This was a prospective comparative clinical observational study by design. A healthy control population was compared with treatment-naïve patients diagnosed with intra- and extraaxial brain tumors. Leukocyte counts (neutrophil, lymphocyte, monocyte, eosinophil, and basophil counts) as well as leukocyte ratios such as the NLR and the monocyte to lymphocyte ratio (MLR) were calculated. We also evaluated if the counts and indices were related to the tumor volume.

RESULTS

In all patients with tumors, the platelet and neutrophil counts were elevated when compared to the controls. In contrast, monocyte counts and the MLR were found to be decreased in patients with tumors when compared to the controls. The subset of patients with glioblastoma showed a significant increase in NLR when compared to the controls.

CONCLUSIONS

Significant changes in the neutrophil, monocyte, and platelet counts as well as NLR and MLR were observed. Prospective longitudinal studies are required to determine the prognostic and therapeutic implications of these findings.

Experimental and theoretical rationalization of the growth mechanism of silicon quantum dots in non-stoichiometric SiN x : role of chlorine in plasma enhanced chemical vapour deposition

Silicon quantum dots (Si-QDs) embedded in an insulator matrix are important from a technological and application point of view. Thus, being able to synthesize them in situ during the matrix growth process is technologically advantageous. The use of SiH₂Cl₂ as the silicon precursor in the plasma enhanced chemical vapour deposition (PECVD) process allows us to obtain Si-QDs without post-thermal annealing. Foremost in this work, is a theoretical rationalization of the mechanism responsible for Si-QD generation in a film including an analysis of the energy released by the extraction of HCl and the insertion of silylene species into the terminal surface bonds. From the results obtained using density functional theory (DFT), we propose an explanation of the mechanism responsible for the formation of Si-QDs in non-stoichiometric SiN _x starting from chlorinated precursors in a PECVD system. Micrograph images obtained through transmission electron microscopy confirmed the presence of Si-QDs, even in nitrogen-rich (N-rich) samples. The film stoichiometry was controlled by varying the growth parameters, in particular the NH₃/SiH₂Cl₂ ratio and hydrogen dilution. Experimental and theoretical results together show that using a PECVD system, along with chlorinated precursors it is possible to obtain Si-QDs at a low substrate temperature without annealing treatment. The optical property studies carried out in the present work highlight the prospects of these thin films for down shifting and as an antireflection coating in silicon solar cells.

False Recognition in Behavioral Variant Frontotemporal Dementia and Alzheimer's Disease-Disinhibition or Amnesia?

Episodic memory recall processes in Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) can be similarly impaired, whereas recognition performance is more variable. A potential reason for this variability could be false-positive errors made on recognition trials and whether these errors are due to amnesia per se or a general over-endorsement of recognition items regardless of memory. The current study addressed this issue by analysing recognition performance on the Rey Auditory Verbal Learning Test (RAVLT) in 39 bvFTD, 77 AD and 61 control participants from two centers (India, Australia), as well as disinhibition assessed using the Hayling test. Whereas both AD and bvFTD patients were comparably impaired on delayed recall, bvFTD patients showed intact recognition performance in terms of the number of correct hits. However, both patient groups endorsed significantly more false-positives than controls, and bvFTD and AD patients scored equally poorly on a sensitivity index (correct hits—false-positives). Furthermore, measures of disinhibition were significantly associated with false positives in both groups, with a stronger relationship with false-positives in bvFTD. Voxel-based morphometry analyses revealed similar neural correlates of false positive endorsement across bvFTD and AD, with both patient groups showing involvement of prefrontal and Papez circuitry regions, such as medial temporal and thalamic regions, and a DTI analysis detected an emerging but non-significant trend between false positives and decreased fornix integrity in bvFTD only. These findings suggest that false-positive errors on recognition tests relate to similar mechanisms in bvFTD and AD, reflecting deficits in episodic memory processes and disinhibition. These findings highlight that current memory tests are not sufficient to accurately distinguish between bvFTD and AD patients.

NGS-based approach to determine the presence of HPV and their sites of integration in human cancer genome

BACKGROUND

Human papilloma virus (HPV) accounts for the most common cause of all virus-associated human cancers. Here, we describe the first graphic user interface (GUI)-based automated tool 'HPVDetector', for non-computational biologists, exclusively for detection and annotation of the HPV genome based on next-generation sequencing data sets.

METHODS

We developed a custom-made reference genome that comprises of human chromosomes along with annotated genome of 143 HPV types as pseudochromosomes. The tool runs on a dual mode as defined by the user: a 'quick mode' to identify presence of HPV types and an 'integration mode' to determine genomic location for the site of integration. The input data can be a paired-end whole-exome, whole-genome or whole-transcriptome data set. The HPVDetector is available in public domain for download: http://www.actrec.gov.in/pi-webpages/AmitDutt/HPVdetector/HPVDetector.html.

RESULTS

On the basis of our evaluation of 116 whole-exome, 23 whole-transcriptome and 2 whole-genome data, we were able to identify presence of HPV in 20 exomes and 4 transcriptomes of cervical and head and neck cancer tumour samples. Using the inbuilt annotation module of HPVDetector, we found predominant integration of viral gene E7, a known oncogene, at known 17q21, 3q27, 7q35, Xq28 and novel sites of integration in the human genome. Furthermore, co-infection with high-risk HPVs such as 16 and 31 were found to be mutually exclusive compared with low-risk HPV71.

CONCLUSIONS

HPVDetector is a simple yet precise and robust tool for detecting HPV from tumour samples using variety of next-generation sequencing platforms including whole genome, whole exome and transcriptome. Two different modes (quick detection and integration mode) along with a GUI widen the usability of HPVDetector for biologists and clinicians with minimal computational knowledge.

Overcoming the effects of false positives and threshold bias in graph theoretical analyses of neuroimaging data

Graph theory (GT) is a powerful framework for quantifying topological features of neuroimaging-derived functional and structural networks. However, false positive (FP) connections arise frequently and influence the inferred topology of networks. Thresholding is often used to overcome this problem, but an appropriate threshold often relies on a priori assumptions, which will alter inferred network topologies. Four common network metrics (global efficiency, mean clustering coefficient, mean betweenness and smallworldness) were tested using a model tractography dataset. It was found that all four network metrics were significantly affected even by just one FP. Results also show that thresholding effectively dampens the impact of FPs, but at the expense of adding significant bias to network metrics. In a larger number (n=248) of tractography datasets, statistics were computed across random group permutations for a range of thresholds, revealing that statistics for network metrics varied significantly more than for non-network metrics (i.e., number of streamlines and number of edges). Varying degrees of network atrophy were introduced artificially to half the datasets, to test sensitivity to genuine group differences. For some network metrics, this atrophy was detected as significant (p<0.05, determined using permutation testing) only across a limited range of thresholds. We propose a multi-threshold permutation correction (MTPC) method, based on the cluster-enhanced permutation correction approach, to identify sustained significant effects across clusters of thresholds. This approach minimises requirements to determine a single threshold a priori. We demonstrate improved sensitivity of MTPC-corrected metrics to genuine group effects compared to an existing approach and demonstrate the use of MTPC on a previously published network analysis of tractography data derived from a clinical population. In conclusion, we show that there are large biases and instability induced by thresholding, making statistical comparisons of network metrics difficult. However, by testing for effects across multiple thresholds using MTPC, true group differences can be robustly identified.

A genetic model for gallbladder carcinogenesis and its dissemination

Gallbladder cancer, although regarded as the most common malignancy of the biliary tract, continues to be associated with a dismal overall survival even in the present day. While complete surgical removal of the tumour offers a good chance of cure, only a fraction of the patients are amenable to curative surgery owing to their delayed presentation. Moreover, the current contribution of adjuvant therapies towards prolonging survival is marginal, at best. Thus, understanding the biology of the disease will not only enable a better appreciation of the pathways of progression but also facilitate the development of an accurate genetic model for gallbladder carcinogenesis and dissemination. This review provides an updated, evidence-based model of the pathways of carcinogenesis in gallbladder cancer and its dissemination. The model proposed could serve as the scaffolding for elucidation of the molecular mechanisms involved in gallbladder carcinogenesis. A better understanding of the pathways involved in gallbladder tumorigenesis will serve to identify patients at risk for the cancer (and who thus could be offered prophylactic cholecystectomy) as well as aid oncologists in planning the most suitable treatment for a particular patient, thereby setting us on the vanguard of transforming the current treatment paradigm for gallbladder cancer.

Epidermal growth factor receptor mutation subtypes and geographical distribution among Indian non-small cell lung cancer patients

BACKGROUND

The Medical Oncology Department at Tata Memorial Hospital, the single largest tertiary cancer care center in Asia, receives in-house registered and referral patient samples from all parts of the country. Our recent studies establish 23% EGFR mutation frequency among Indian population. Here, we extend our study and report further analysis of distribution of different types of EGFR mutations in 1018 non small cell lung cancer patient, and its co-relation with clinical parameters and geographical variations across the country.

MATERIAL AND METHODS

This study is a retrospective analysis on all the patients who were referred for EFGR testing as a routine service over a 1.5 year period. This was part of standard care. EGFR kinase domain mutations in exon 18-21 were probed by TaqMan probe-based assays in 1018 NSCLC patients.

RESULTS AND DISCUSSION

While EGFR exon 19 mutations, the most frequent EGFR mutation, were found be higher among non smokers females, we find surprisingly higher incidence of exon 21 mutations among EGFR mutation positive male smokers of Indian ethnicity. Furthermore, as Indian population is known to be composed of a gradient admixture of Ancestral North Indian (with genetic influence from Middle Easterners, Central Asians, and Europeans harboring variant EGFR mutation frequency) and Ancestral South Indians, as a paradox our study indicates comparable EGFR mutation frequency across different geographical locations within India

CONCLUSION

Geographically there is uniform distribution in the EGFR mutation frequency within India. Further more, while exon 19 mutations are predominant among non smokers, higher incidence of exon 21 mutations exists among EGFR mutation positive male smokers of Indian ethnicity.

An Indian adaptation of the Involvement Evaluation Questionnaire: similarities and differences in assessment of caregiver burden

OBJECTIVES

The Involvement Evaluation Questionnaire (IEQ) is a comprehensive, conceptually valid and reliable means of assessing caregiver burden. However, its psychometric properties have rarely been examined in non-European settings. The aim of the present study was to evaluate the psychometric properties of an Indian translation of the IEQ (Hindi-IEQ).

METHODS

The European Union (English) version of IEQ was translated into Hindi and reviewed by a group of experts and caregivers for translation accuracy, cultural appropriateness, and for relevance and acceptability of items and constructs. The Hindi-IEQ was then administered to 162 primary caregivers of patients with severe mental illnesses. Eighteen caregivers completed both the English and Hindi versions to check the level of agreement between them. Another 27 completed the Hindi-IEQ twice, a week apart, to evaluate its test-retest reliability. Factor structure of the Hindi-IEQ was examined using an exploratory, principal components and factor analysis.

RESULTS

Pearson's correlation coefficients were significant for 24 items, while intraclass correlation coefficients were significant for 28 of the 31 items (P < 0.05), indicating a satisfactory level of agreement between the Hindi and English versions. Test-retest reliability for all items of the Hindi-IEQ was adequate, with kappa values ranging from 0.46 to 0.95 and intraclass correlation coefficients from 0.76 to 1.00. Internal consistency (Cronbach's alpha = 0.89) and the split-half reliability (Spearman-Brown coefficient = 0.68) of the Hindi-IEQ were also satisfactory. However, several differences were noted in the factor structure and distribution of scores of the Hindi-IEQ, which were quite unlike that of the European Union version.

CONCLUSIONS

The similarities and differences between the 2 versions of the IEQ indicated that sociocultural factors could influence assessment of caregiver burden across different cultures.

Do COMT, BDNF and NRG1 polymorphisms influence P50 sensory gating in psychosis?

BACKGROUND

Auditory P50 sensory gating deficits correlate with genetic risk for schizophrenia and constitute a plausible endophenotype for the disease. The well-supported role of catechol-O-methyltransferase (COMT), brain-derived neurotrophic factor (BDNF) and neuregulin 1 (NRG1) genes in neurodevelopment and cognition make a strong theoretical case for their influence on the P50 endophenotype.

METHOD

The possible role of NRG1, COMT Val158Met and BDNF Val66Met gene polymorphisms on the P50 endophenotype was examined in a large sample consisting of psychotic patients, their unaffected relatives and unrelated healthy controls using linear regression analyses.

RESULTS

Although P50 deficits were present in patients and their unaffected relatives, there was no evidence for an association between NRG1, COMT Val158Met or BDNF Val66Met genotypes and the P50 endophenotype.

CONCLUSIONS

The evidence from our large study suggests that any such association between P50 indices and NRG1, COMT Val158Met or BDNF Val66Met genotypes, if present, must be very subtle.

Utilisation behaviour in frontotemporal dementia

OBJECTIVE

To study the occurrence of utilisation behaviour (UB) in patients with frontotemporal dementia (FTD).

MATERIALS AND METHODS

Twenty patients who fulfilled all core Consensus statement criteria for FTD were examined by a neurologist experienced in dementia and by a clinical neuropsychologist. All patients had imaging evidence of predominantly frontal or frontotemporal involvement. Behavioural data were obtained from care givers using a semistructured questionnaire. Questions related to UB were asked in detail. Further assessment for UB was done during the interview with the patient using common objects. Only frank and coherent UB was considered for the study. For comparison, 34 patients with probable Alzheimer's disease diagnosed by the NINCDS-ADRDA criteria were also similarly studied.

RESULTS

80 per cent of our patients with FTD but none with probable Alzheimer's disease exhibited UB. Fourteen out of the 16 patients with FTD who exhibited UB were less than 70 years old. Among patients with UB, 88% exhibited a wide range of 'incidental' UB. Objects of daily use tended to trigger UB most commonly. Utilisation behaviour tended to correspond to premorbid habits in at least 75% of our patients.

CONCLUSION

Utilisation behaviour may be more common in FTD patients than is currently recognised. The presence of UB should be queried in every patient suspected to be suffering from FTD. A comprehensive questionnaire for UB such as that used here could be useful.

The effect of COMT, BDNF, 5-HTT, NRG1 and DTNBP1 genes on hippocampal and lateral ventricular volume in psychosis

BACKGROUND

Morphometric endophenotypes which have been proposed for psychotic disorders include lateral ventricular enlargement and hippocampal volume reductions. Genetic epidemiological studies support an overlap between schizophrenia and bipolar disorder, and COMT, BDNF, 5-HTT, NRG1 and DTNBP1 genes have been implicated in the aetiology of both these disorders. This study examined associations between these candidate genes and morphometric endophenotypes for psychosis.

METHOD

A total of 383 subjects (128 patients with psychosis, 194 of their unaffected relatives and 61 healthy controls) from the Maudsley Family Psychosis Study underwent structural magnetic resonance imaging and genotyping. The effect of candidate genes on brain morphometry was examined using linear regression models adjusting for clinical group, age, sex and correlations between members of the same family.

RESULTS

The results showed no evidence of association between variation in COMT genotype and lateral ventricular, and left or right hippocampal volumes. Neither was there any effect of the BDNF, 5-HTTLPR, NRG1 and DTNBP1 genotypes on these regional brain volumes.

CONCLUSIONS

Abnormal hippocampal and lateral ventricular volumes are among the most replicated endophenotypes for psychosis; however, the influences of COMT, BDNF, 5-HTT, NRG1 and DTNBP1 genes on these key brain regions must be very subtle if at all present.

Integrated genomic profiling of endometrial carcinoma associates aggressive tumors with indicators of PI3 kinase activation

Although 75% of endometrial cancers are treated at an early stage, 15% to 20% of these recur. We performed an integrated analysis of genome-wide expression and copy-number data for primary endometrial carcinomas with extensive clinical and histopathological data to detect features predictive of recurrent disease. Unsupervised analysis of the expression data distinguished 2 major clusters with strikingly different phenotypes, including significant differences in disease-free survival. To identify possible mechanisms for these differences, we performed a global genomic survey of amplifications, deletions, and loss of heterozygosity, which identified 11 significantly amplified and 13 significantly deleted regions. Amplifications of 3q26.32 harboring the oncogene PIK3CA were associated with poor prognosis and segregated with the aggressive transcriptional cluster. Moreover, samples with PIK3CA amplification carried signatures associated with in vitro activation of PI3 kinase (PI3K), a signature that was shared by aggressive tumors without PIK3CA amplification. Tumors with loss of PTEN expression or PIK3CA overexpression that did not have PIK3CA amplification also shared the PI3K activation signature, high protein expression of the PI3K pathway member STMN1, and an aggressive phenotype in test and validation datasets. However, mutations of PTEN or PIK3CA were not associated with the same expression profile or aggressive phenotype. STMN1 expression had independent prognostic value. The results affirm the utility of systematic characterization of the cancer genome in clinically annotated specimens and suggest the particular importance of the PI3K pathway in patients who have aggressive endometrial cancer.

An epidemiologic study of mild cognitive impairment in Kolkata, India

OBJECTIVES

To estimate the prevalence of two types of mild cognitive impairment (MCI)-amnestic and multiple domain types-among nondemented and nondepressed elderly subjects aged 50 and older.

METHODS

The study was carried out in Kolkata, the eastern metropolis of India. A cross-sectional community screening was carried out, and 960 subjects were selected by systematic random sampling for the assessment of cognitive function with the help of a validated cognitive questionnaire battery administered through house-to-house survey. A case-control study was also undertaken to identify potential risk factors through univariate analysis.

RESULTS

Ultimately, full evaluation of cognitive function was possible in 745 of 960 subjects. An overall prevalence of MCI detected based on neuropsychological testing was 14.89% (95% CI: 12.19 to 17.95). Prevalence of the amnestic type was 6.04% (95% CI: 4.40 to 8.1) and that of the multiple domain type was 8.85% (95% CI: 6.81 to 11.32). Adjusted for age, education. and gender, the amnestic type was more common among men and the multiple domain type among women with advancement of age. Rates differed considerably with educational attainment. Hypertension and diabetes mellitus were the major risk factors for both types of MCI.

CONCLUSION

In this first community-based study of mild cognitive impairment (MCI) from India, prevalence of the amnestic type is comparable with and that of the multiple domain type is less than the prevalence in developed countries. Variations in age, education, and gender specific prevalence of MCI of both types were encountered. The putative risk factors identified merit further study.

Dementia in india--a critical appraisal

Dementia is a clinical syndrome characterised by acquired loss of cognitive and emotional abilities that interfere with activities of daily living. It is a disease of the older adults. The overall prevalence of dementia in developed countries has been reported to be between 5% and 10% after 60 or 65 years and older. India is the second largest populous country. The prevalence doubles with every five-year increase in age. Looking at some studies, it appears that the prevalence of dementia in India is lower as compared to developed countries and even from other developing countries. The probable reasons for lower prevalence in India are enumerated as: False negatives, low life expectancy, shorter survival and duration of disease, low age-specific incidence. Risk factors include greater age, female sex, less education, positive family history, Down's syndrome, stroke and its risk factors, head trauma with loss of conscionsness and thyroid diseases. Protective factors include higher education, APOE2 gene, intake of antioxidant substances, use of anti-inflammatory drugs, oestrogen supplements in women and also cigarette smoking (controversial). Alzheimer's disease has been found to be commonest cause of dementia. Patients of dementia require proper evaluation and management requires a multidisciplinary approach. The government and the social organisations should come forward and only a concerted effort of all people in every sphere of life will enable to tackle the new menace of this country.

Correlation between CT scan and automated perimetry in supratentorial tumors

An attempt was made to correlate various types of visual field defects on automated perimetry with the findings of computed tomography in 44 patients of supratentorial tumors. All the patients above the age of 10 years were subjected to complete neurological examination including investigations like plain X-rays and CT scan, however, MRI and angiography were performed wherever indicated. Ocular examination particularly pertaining to neuro-ophthalmological profile was carried out with special emphasis on automated perimetry on Humphrey field analyser. The results indicated that automated perimetry was capable of reliably detecting and quantitating the visual field defects and thus established the location of the tumor in 72% patients when compared to CT scan. Hence, any patient with neuro-ophthalmic features should be subjected to automated perimetry for early diagnosis and probable location of intracranial space occupying lesion affecting visual pathways.

Functional expression of the renal organic cation transporter and P-glycoprotein in Xenopus laevis oocytes

The hypothesis that P-glycoprotein (P-gp) mediates the renal secretion of organic cations was tested by functional expression of mRNAs in the Xenopus laevis oocyte system. Efflux of 2'-deoxytubercidin (dTub), a substrate for the renal organic cation transporter (OCT) but not for P-gp, was enhanced by injection of renal mRNA but not by injection of mRNA from P-gp-overexpressing cells (MDCK cells transduced with the cDNA for human MDR1). The functional capacity of the MDCK-MDR mRNA was established by its ability to reduce the steady-state uptake of a classical P-gp substrate, vinblastine. Thus, these data indicate OCT and P-gp to be distinct entities. The Xenopus oocyte system provides a functional approach to further characterize the OCT.

Enhanced transepithelial flux of cimetidine by Madin-Darby canine kidney cells overexpressing human P-glycoprotein

Cimetidine has been used as a relatively selective inhibitor of renal organic cation secretion, analogous to the use of probenecid to inhibit organic anion secretion. Many of the substrates for the multidrug transporter P-glycoprotein, which is overexpressed in multidrug-resistant tumor cells, are organic cations. Furthermore, the protein is normally expressed on the apical membranes of proximal tubule cells, the postulated site for active organic cation secretion. To test directly whether P-glycoprotein might serve as a carrier for cimetidine, we measured cimetidine transepithelial movement across Madin-Darby canine kidney cells grown as monolayers on membrane filters. A retrovirally transduced Madin-Darby canine kidney cell line (Madin-Darby canine kidney cells transfected with the human multiple drug resistance 1 cDNA for P-glycoprotein), that expresses the human form of P-glycoprotein on its apical membrane, had an increased capacity to transport cimetidine from the basolateral to apical medium (b-->a) but not in the reverse direction (i.e., a-->b). Qualitatively similar results were observed with daunomycin, a well established substrate for P-glycoprotein. Cellular uptake and energy-dependent efflux experiments further established cimetidine to be a substrate for the human P-glycoprotein. Thus, P-glycoprotein may play a role in the renal secretion of cimetidine and perhaps other organic cations.

P-glycoprotein and organic cation secretion by the mammalian kidney

On the basis of physiological localization, broad substrate specificity and energy dependence, the role of the kidney P-glycoprotein was tested in the energy-dependent renal secretion of organic cations. P-glycoprotein-enriched vesicles from Cl 1D/VCR [a multidrug-resistant (MDR) cell line] displayed enhanced transport of the MDR drug vinblastine and the organic cation cimetidine but not of the organic cation tetraethylammonium (TEA) over that shown by vesicles prepared from the drug-sensitive parental line Cl 1D. An outwardly directed proton gradient stimulated TEA and cimetidine uptake by renal brush border membrane vesicles (BBMV) but this gradient did not enhance the uptake of these organic cations into Cl 1D/VCR vesicles. Vinblastine uptake was unaffected by the proton gradient in either vesicle preparation. An outwardly directed gradient of TEA enhanced the uptake of TEA into renal BBMV but did not do so in the case of Cl 1D/VCR vesicles. These data indicate that P-glycoprotein, which is normally energized by ATP hydrolysis, is incapable of catalyzing organic cation/proton exchange or organic cation/organic cation exchange, properties of the organic cation carrier of renal proximal tubule BBMV. The MDR substrates and modulators inhibited the uptake of vinblastine and cimetidine by Cl 1D/VCR vesicles and the uptake of cimetidine and TEA by renal BBMV. Several organic cations studied inhibited TEA and cimetidine uptake by renal BBMV but did not inhibit the uptake of vinblastine and cimetidine by Cl 1D/VCR vesicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Tidal breath flow-volume curves in obstructive sleep apnea

Because of the gravitational position during sleep and the associated relaxed state, we hypothesized that passive expiration in the supine position might reflect upper airway pathophysiology in obstructive sleep apnea (OSA). We prospectively enrolled and tested 92 subjects with several clinical conditions. Maximal comfort and relaxation during expiration was achieved by connecting subjects to a ventilator via a mouthpiece. An initial respiratory rate of 16 breaths/min and tidal volume of 10 ml/kg were selected. Fine adjustments were then made to achieve maximal subject relaxation. Using this method, we obtained reproducible tidal breath flow-volume curves (TBFVC). Testing was performed in both sitting and supine positions. Standard pulmonary function tests, including spirometry and lung volume measurements, were also obtained in both sitting and supine positions. Of 86 patients who could be evaluated, 12 (60%) of 20 subjects with documented OSA (respiratory disturbance index: mean, 64.8; range, 10 to 120.5) demonstrated a positional change in the terminal portion of the TBFVC; 10 (32%) of 31 with a history of snoring also tested positive, but only three (9%) of 35 subjects with no OSA, by polysomnography (n = 8) or questionnaire (n = 27), demonstrated such a positional change. This positional change in TBFVC, which was significantly more frequent in subjects with OSA, could not be attributed to any measurable pulmonary function abnormality or body mass index. We believe this positional change in TBFVC reflects upper airway functional narrowing induced by assumption of supine position and decreasing airflow rates.

Postnatal development of organic cation transport and mdr gene expression in mouse kidney

The apical surface of the proximal tubular epithelium is the site of both P-glycoprotein localization and postulated active secretion of organic cations in the mammalian kidney. P-glycoprotein has been shown to act as a pleiotropic drug efflux pump across the cell membrane of tumor cells expressing the multidrug resistance phenotype, whereas the renal organic anion and organic cation secretory systems serve the function of pleiotropic drug transport across the proximal tubule epithelium. Because most known substrates for P-glycoprotein are organic cations, we tested the hypothesis that the physiological function of this protein in the kidney is to mediate renal organic cation secretion. In one approach, we compared the postnatal development of organic cation transport with that of kidney mdr gene expression. Cimetidine-sensitive uptake of classical substrates for renal secretion (N-methyl nicotinamide and tetraethylammonium) into kidney slices developed gradually in neonate mice, reaching adult capacity in 4 to 6 weeks. P-glycoprotein and its mRNA, as estimated by immunohistochemical methods and RNAse protection analysis, were undetectable at birth and were expressed abruptly at the adult level between 2 and 3 weeks of age. In another approach, classical inhibitors of renal organic cation secretion (cimetidine and cyanine 863) failed to reverse resistance to adriamycin in Chinese hamster ovary and P388 cell lines, which possess the phenotypic traits of multidrug resistance. These results suggest that the cimetidine-sensitive component of organic cation secretion is mediated by a protein other than the P-glycoprotein in the mammalian kidney.

Effect of reserpine on the inhibition of prolactin released from different pituitary constructs in vitro by dopamine, bromocriptine and apomorphine

Hourly release of Prolactin by pituitary constructs 1 whole pituitary (PI), adenohypophysis (P-N) and pituitary-hypothalamus co-incubate (PHC) were compared. Adenohypophysis secreted significantly more prolactin than PI and PHC, while PHC secreted significantly less than PI. Co-incubation of (P-N) with posterior pituitary reduced the elevated secretion of prolactin. Addition of dopamine (10(-7) M), bromocriptine (10(-7) M) and apomorphine (5 x 10(-8) M) to these constructs did not affect the release of prolactin from PI but inhibited the same from (P-N) and PHC. Treatment with reserpine increased serum prolactin levels but intrapituitary prolactin contents were decreased. Hourly release of prolactin from pituitary constructs derived from reserpine-treated rats was significantly reduced as compared to ascorbic acid--treated controls. Inclusion of dopamine (10(-7) M), bromocriptine (10(-7) M) and apomorphine (5 x 10(-8) M) in these constructs inhibited prolactin secretion further. In vitro addition of perphenazine stimulated the release of prolactin by PHC but was without any effect on PI and (P-N). The data are interpreted to suggest that dopamine in posterior pituitary may be an important determinant of hypothalamic modulation of prolactin secretion.

Epidemiology of extrapulmonary tuberculosis. A comparative analysis with pre-AIDS era

To study the changes in the epidemiology of extrapulmonary tuberculosis in Tennessee, we compared the 454 cases of extrapulmonary tuberculosis reported between 1977 and 1981 with 356 cases encountered between 1982 and 1986. The data were analyzed by age, sex, race and site of the disease which were compared with the national statistics during the periods. We observed that 11.3 percent of the total TB cases were extrapulmonary. Unlike national statistics, the proportion of extrapulmonary tuberculosis had remained unchanged between the two study periods. Except for a significant decline (p less than 0.001) in genitourinary tuberculosis, the incidence of other extrapulmonary TB had remained the same. The higher incidences of lymphatic, miliary, and meningeal TB were noted in nonwhites, particularly in the younger population, during both study periods. While the national trend showed a steady increase in the percentage of extrapulmonary TB cases, there was no change in Tennessee. The reason for a continued decline of GU TB remains unclear. Although AIDS may have contributed toward the increase nationally, fewer cases of AIDS in the state have not influenced the proportion of extrapulmonary TB. Awareness of such regional differences in the epidemiology of TB, and the impact of HIV infection, will be very useful to physicians and other health care providers involved in the diagnosis, treatment, and prevention of tuberculosis.

Diurnal variations and temporal coupling of bioactive and immunoactive luteinizing hormone, prolactin, testosterone and 17-beta-estradiol in adult men

Diurnal variations and temporal coupling in the circulating levels of immunoactive and bioactive luteinizing hormone (LH) and prolactin (PRL), testosterone (T) and 17-beta-estradiol (E2) in plasma of 6 healthy men (mean age 33 years) were studied. Each hormonal profile was analyzed for circadian amplitude, acrophase and nadir. Acrophases for immunoactive LH and T were coincident and ranged between clock hours 1 and 5. Acrophase for bioactive LH ranged between 9 and 12 h and was coincident with nadir for T. Acrophase for E2 ranged between 15 and 18 h and was coincident with nadir for immunoactive LH (15-17 h). Acrophase for bioactive PRL and immunoactive PRL ranged between 20-23 and 23-4 h, respectively. The circadian amplitude for T showed a negative correlation coefficient with circadian amplitude of bioactive LH (alpha = -0.86) and positive correlation coefficient with circadian amplitude of immunoactive LH (alpha = 0.94). It is inferred that immunoactive LH may be a sensor of T concentration while bioactive LH may be actually involved in the feedback regulation of T secretion. It is suggested that PRL may have a key role in the regulation of LH secretion.

Lactosaminoglycan assembly, cell surface expression, and release by mouse uterine epithelial cells

The kinetics of assembly, cell surface expression, secretion, and degradation of the major lactosaminoglycan (LAG)-bearing glycoproteins in mouse uterine epithelial cells have been studied. LAGs have been shown previously to be synthesized preferentially by these cells in the uterus and are expressed at the cell surface, where they participate in cell adhesion processes (Dutt, A., Tang., J.-P., and Carson, D. D. (1987) Dev. Biol. 119, 27-37). We utilized selection on pokeweed mitogen-Sepharose, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and subsequent electroelution to isolate the major LAG-bearing glycoproteins. The intact LAG-bearing glycoproteins exhibited very high apparent Mr (greater than 500,000) both by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and molecular exclusion chromatography under dissociative conditions. The subset of LAGs at the cell surface exhibited a half-life of approximately 11 h, whereas total cell-associated LAGs had a half-life of 6 +/- 1 h. Pulse-chase experiments indicated that the transit time of LAG core proteins from the rough endoplasmic reticulum to the site of LAG addition in the Golgi was 30-45 min. LAG glycoprotein transit from the Golgi to the cell surface required at least an additional 30-45 min. The major metabolic fate of the cell-associated LAGs was secretion to the medium with no evidence of lysosomal degradation. Some (30%) of the LAGs appeared to be released to the medium via the action of cell surface proteases. Epithelial cell surfaces bound fluoresceinated pokeweed mitogen, indicating the constitutive presence of LAG-bearing molecules at the cell surface; pokeweed mitogen binding to the cell surface was completely blocked by 10 mM chitotriose. These observations provide the first comprehensive description of the intracellular transport and metabolism of this interesting class of glycoproteins of the uterine epithelial cell surface.

Estrogen preferentially stimulates lactosaminoglycan-containing oligosaccharide synthesis in mouse uteri

The effects of steroid hormones on the synthesis of lactosaminoglycan (LAG)-containing oligosaccharides by mouse uteri are reported. The uterine LAG-containing oligosaccharides were degraded partially by Pseudomonas endo-beta-galactosidase, releasing an oligosaccharide of the apparent structure: Gal beta----N-acetylglucosaminyl(----N-acetylgalactosaminyl)beta 1,3----galactose. A larger fraction of the LAG-containing oligosaccharides bound to pokeweed mitogen than to Datura stramonium lectin, suggesting the presence of highly branched structures. LAG-containing oligosaccharides were resistant to sequential digestion with Pronase, nitrous acid, hyaluronidase, and chondroitinase ABC. These polysaccharides exhibited a Gal:GlcNAc:GalNAc ratio of approximately 1.0:1.0:0.3 and were not fucosylated. The ion-exchange behavior of the LAG-containing oligosaccharides before and after mild acid hydrolysis indicated the presence of sialic acid residues. The LAG-containing glycopeptides were highly resistant to beta-elimination but were released quantitatively by hydrazinolysis, demonstrating an N-linkage to protein. Binding to pokeweed mitogen was markedly enhanced following release of these oligosaccharides from peptides by hydrazinolysis, suggesting that peptide-bound oligosaccharides were partially inaccessible to the lectin. Molecular exclusion chromatography of the oligosaccharides released by hydrazinolysis revealed a broad distribution ranging from Mr 4,000 to 15,000 with a median Mr of approximately 8,000. We extended the above observations by determining how the steroid hormones 17-beta-estradiol (E2) and progesterone affected synthesis of the LAG-containing oligosaccharides in ovariectomized mice. Generally, E2 and a number of E2 agonists stimulated glycoconjugate synthesis; however, chronic E2 treatment or combined treatment with E2 plus progesterone caused the synthesis of most glycosaminoglycans to return to basal levels. In contrast, E2 either alone or in combination with progesterone stimulated synthesis of LAG-containing oligosaccharides in preference not only to glycosaminoglycans but also to other classes of N-linked oligosaccharides. This effect was apparent during both priming and nidatory E2 treatments. Collectively, these data provide the first demonstration of LAG-containing oligosaccharides in uteri and for the hormonally regulated synthesis of lactosaminoglycans. In addition, this is the first demonstration of the ability of steroid hormones to induce the synthesis of certain types of N-linked oligosaccharides in preference to others in the same tissue.