P16.01.A Factors predicting cognitive impairment after intrathecal methotrexate treatment in patients with non-small cell lung cancer and leptomeningeal disease

Background

Leptomeningeal disease (LD) is a devastating cancer-related neurological complication. LD accounts for 4-15% of patients with non-small cell lung cancer (NSCLC). In this population, the median overall survival (OS) with intrathecal (IT) methotrexate (MTX) plus systemic therapy (ST) is 4-6 months (m). Until now, disease and treatment-related cognitive impairment (CI) has been poorly studied in this group.

Material and Methods

Patients with NSCLC and LD treated with IT MTX in our institution between 2010 and 2021 were retrospectively studied. LD was diagnosed based on positive cerebrospinal fluid cytology or radiological findings in the brain/spinal MRI plus suitable clinical signs/symptoms. IT MTX (12mg twice weekly for 4 weeks, then 12mg weekly for 4 weeks) was given in combination with ST. Patients’ clinical characteristics and patient-reported CI were assessed at baseline and at 3-months post IT MTX. A Kaplan-Meier survival analysis was performed. Primary endpoint: predictive factors of CI at 3m post IT MTX. Secondary endpoint: prognostic factors.

Results

Out of 55 patients included, 51% were male and median age at LD diagnosis was 59 years old (range 38-78). Most patients had an ECOG PS≤1 (76.4%) and adenocarcinoma histology (83.6%). 47% of patients harbored EGFR mutation. In 23.6% of patients LD was diagnosed synchronously with lung tumor and for patients without LD at tumor diagnosis, the median time to LD development was 8m (range 0-73). Clinical features at LD diagnosis were 43.7% infratentorial symptoms, 29% CI, 20% multiple symptoms and 7% asymptomatic. At LD diagnosis, 53% of patients had synchronous brain metastases (BM) and in 38% the systemic disease was not controlled. 85.5% of patients received ST concurrently with IT MTX (N=22 chemotherapy, N=22 TKIs and N=3 immunotherapy). 14.5% of patients did not receive ST.

Median OS from IT was 5m (95% CI 1.3-8.6). ECOG PS and ST administered concurrently with IT MTX was associated with longer OS (p<0.05). 23.6% of patients developed CI at 3m post IT therapy. Median OS for patients without and with CI post IT therapy was 6m (95% CI 0.7-11.3) vs 4m (95% CI 0.5-75) respectively (p=0.15). Patients with leukoencephalopathy at baseline (score≥2in the periventricular Fazekas’ score) (p=0.033), women (p<0.01) and those ≥60 years (p=0.04) were more likely to present CI 3m post IT MTX. The presence of cardiovascular risk factors, previous brain radiotherapy and concurrent BM was not statistically associated with CI.

Conclusion

In this cohort, 24% of patients with NSCLC and LD treated with IT MTX will develop CI 3m post treatment. Baseline leukoencephalopathy, female gender, elder than 60 years old were more likely to exhibit CI after IT MTX. A better characterization of these patients is warranted to develop new treatment strategies to prevent/reduce CI.

Heterogeneous electro-Fenton as plausible technology for the degradation of imidazolinium-based ionic liquids

Conventional water treatments are generally inadequate for degradation of emerging pollutants such as ionic liquids (ILs). The use of heterogeneous electro-Fenton (HEF) has attracted great interest, due to its ability to efficiently oxidize a wide range of organic pollutants operating in cycles or in continuous mode. In this study, the removal of a complex IL from the imidazolinium family (1,3-Bis(2,4,6-trimethylphenyl)imidazolinium chloride), by means of HEF using iron alginate spheres as catalyst has been investigated, resulting in significant TOC decay after 6 h. The optimization of the key process parameters (current, IL concentration and catalyst dosage) has been performed using a Box-Behnken experimental design and achieving 76.98% of TOC abatement in 2 h of treatment. Current proved to be a crucial parameter and high catalyst dosage is required to achieve the maximum removal. In addition, an insight about the availability of iron into the reactor and the evolution of several intermediates has been carried out by employing differential pulse voltammetry on screen-printed carbon electrodes. The evolution of the different voltammetric peaks confirmed the influence of iron release, and the generation of several iron complexes has permitted the comprehension of the degradation pathway, which has been validated by chromatographic techniques.

Updated remission duration and survival results of single-agent clofarabine in previously untreated older adult patients with acute myelogenous leukemia (AML) unlikely to benefit from standard induction chemotherapy due to unfavorable baseline risk factor(s)

7062

Background: The CLASSIC II trial has previously reported an independently confirmed overall remission rate of 46% (38% CR and 8% CRp) and 30- and 60-day mortality rates of 9.8% and 16.1%, respectively (Blood 112: 558, 2008). We now report updated duration of remission (DOR), disease-free survival (DFS), and overall survival (OS). Methods: Single arm, multi-center, phase II, open-label, 2-stage study of patients with untreated AML, ≥60 years old, and at least one adverse prognostic factor: age ≥70 years, antecedent hematologic disorder (AHD), PS = 2, and/or intermediate/unfavorable risk karyotype. Clofarabine (CLO) administered days 1–5 at 30 mg/m2 during induction and 20 mg/m2 during re-induction/consolidation for maximum 6 cycles. Patients were followed for at least 6 months past remission (CR/CRp). Results: 116 patients enrolled and 112 in full analysis set. Median age 71 years. Median DOR (censored at alternative therapy) for CR/CRp was 56 weeks (95% CI, 33 weeks - not yet estimable [n/e]) and for CR 65 weeks (95% CI, 41 weeks - n/e). Median DFS (not censored at alternative therapy) for CR/CRp was 34 weeks (95% CI, 24 - 65 weeks). Median OS was 41 weeks (95% CI 28 - 53 weeks), for CR/CRp 59 weeks (95% CI, 50 weeks - n/e ), and for CR was 72 weeks (95% CI, 53 weeks - n/e) after median follow-up of 36 weeks (range, 1 - 85 weeks). Thirty-day mortality was 9.8% for all patients with 4.7% and 13% for age <70 and age ≥70 years, respectively. Conclusions: These data expand on the previously reported efficacy and safety data of single agent CLO in adult AML. Complete remissions appear durable (median >1 yr), and DFS and OS compare favorably to historical experience, particularly in patients with these adverse prognostic factors. These results suggest that single agent CLO is an effective and tolerable treatment option for older adult patients with untreated AML and 1 or more unfavorable baseline prognostic factor(s).

[Table: see text]

Does pre-imatinib (IM) fluorescence in situ hybridization (FISH) predict myelosuppression and outcomes in chronic myeloid leukemia (CML)?

7071

Background: IM-associated myelosuppression occurs in 4–40% of CML patients (pts) vs. 1–16% in GIST. Selective inhibition of predominantly Philadelphia chromosome (Ph+) driven hematopoiesis may explain development of myelosuppression. In the absence of clinically applicable methods to quantitate Ph+/Ph- progenitor ratio, we hypothesized that the pre-IM percentage of BCR-ABL+ cells measured by FISH predicts myelosuppression. Methods: FISH pre-IM was available in 58 CML pts with chronic phase (CP, n=52), or advanced phase (AP, accelerated =3, blast =3) at 2 institutions. Grade >3 myelosuppression occurred < 60 days from starting IM in 9 pts (400 mg/d=6, > 600 mg/d=3), leading to dose reduction (4), discontinuation (1) or continuation same dose IM despite myelosuppression (4). Cryopreserved marrow CD34+/CD38- cells from 14 pts with (7) or without (7) post-IM myelosuppression were sorted using flow cytometry and subjected to FISH analyses. Results: Median FISH was higher for myelosuppression (90%) vs. no myelosuppression (80%) pts (p= 0.03), and in AP vs. CP (97 % vs. 80%, p=0.003). Results of FISH on CD34+/CD38- cells will be reported. Table summarizes outcomes of CP pts. Median follow-up was 14 and 45 months for myelosuppression and no myelosuppression AP pts, respectively. Myelosuppression AP pts expired (CML=2, GVHD=1); 1 after complete hematologic (CHR) and minor cytogenetic response (CTGR), 1 after partial HR, and 1 resistant disease. All 3 pts without myelosuppression achieved CHR with major CTGR, and 2 had partial molecular response. 1 died from GVHD. Conclusions: Higher FISH pre-IM identifies a group of CML pts who develop myelosuppression and are less likely to respond to IM.

[Table: see text]

No significant financial relationships to disclose.

Monitoring chronic myeloid leukemia (CML) response to tyrosine kinase inhibitors (TKI) and homoharringtonine (HHT) using peripheral blood (PB) fluorescence in situ hybridization (FISH) and quantitative RT-PCR (Q-PCR): Are bone marrow biopsies still needed?

7064

Background: The purpose of this study is to compare simultaneously obtained PB and bone marrow (BM) BCR-ABL FISH and Q-PCR to monitor response to TKI and HHT in CML. Methods: Between January 2005 and December 2008, 52 patients (pts) with chronic (n = 37, 80%), accelerated (n = 6, 7%), and blast phase (n = 9, 14%) CML had 112 simultaneous PB and BM FISH and Q-PCR before and/or after start of imatinib (IM, n = 27), dasatinib (n = 9), nilotinib (n = 1), bosutinib (n = 13), or HHT (n = 2) for newly diagnosed (n = 27), IM resistant (n = 20), or IM intolerant (n = 5) CML. 13 (26%) had chromosomal abnormalities in addition to the Philadelphia chromosome, and 10 (20%) had a detectable BCR-ABL mutation including the T315I in 2 pts. Results: 24 (46%) had simultaneous PB and BM FISH and/or Q-PCR measurements obtained at 1 time point, 9 (17%) at 2; 9 (17%) at 3; 10 (20%) at > 4 time points before and/or post-initiation of TKI or HHT. Excellent concordance was observed between PB and BM at all time points for both FISH (r = 0.96; p = 0.0003) and Q-PCR (r = 0.88; p= 0.0015). Correlation was not affected by the presence of additional chromosomal abnormalities, phase of the disease, treatment (TKI or HHT), or the number of prior therapies. Conclusions: FISH and Q-PCR are reliable methods to monitor CML response to TKI and HHT in patients with CML and may render the need for BM biopsy monitoring obsolete.

No significant financial relationships to disclose.

The occurrence of idiopathic secondary post-transplant thrombocytopenia and the kinetics of platelet recovery predict survival in patients undergoing autologous hematopoietic progenitor cell transplantation

7109

Background: The frequency and clinical significance of secondary thrombocytopenia following initial engraftment in autologous hematopoietic progenitor cell transplantation (HPCT) is unknown. Methods: An IRB-approved retrospective study of thrombopoiesis in 359 patients transplanted with autologous blood (97%) or marrow (3%) who achieved transfusion-independent platelet engraftment to >50,000/mcL. Idiopathic secondary post-transplant thrombocytopenia (ISPT) was defined as >50% decline in blood platelets to <100,000/mcL in the absence of relapse or sepsis. Results: 62 of 359 study subjects (17%) met the criteria for ISPT within the first 100 days post-transplant. Patients with ISPT had more rapid platelet engraftment (17 + 5 days) versus non-ISPT patients (18 + 18 days; p=0.002) and partial recovery of platelet counts (median 96K/mcL) by day 75 post-transplant. The median survival for the entire population was 6.2 years with shorter survival in AML (1.3 years), breast cancer (6.2 years) and myeloma (5.5 years) than lymphoma patients (median not reached). Co- variates associated with post-transplant death (p<0.1) were entered into a multivariable logistic regression analysis stratified by cancer diagnosis at the time of transplant. Three factors were independently associated with worse survival: the number of prior chemotherapy regimens, failure to achieve a normal platelet counts post-transplant, and the occurrence of ISPT. A prognostic score was developed based upon the occurrence of ISPT and post-transplant platelet counts of <150,000/mcL. Survival of patients with both factors (n=25) was poor (15% alive at 5 years); patients with one factor (n=145) had 49% 5-year survival; patients with 0 factors (n=189) had 72% 5-year survival. Patients who failed to achieve a normal post-transplant platelet count received significantly fewer CD34+ cells/kg (P<0.001), while patients with ISPT received fewer CD34+CD38- cells/kg (P=0.001). Conclusion: ISPT reflects poor engraftment with long-term-repopulating CD34+ CD38- stem cells. The quantity and quality of autologous HPC in the graft are important prognostic variables for long-term survival.

No significant financial relationships to disclose.

Prevalence of delirium in a geriatric convalescence hospitalization unit: patient's clinical characteristics and risk precipitating factor analysis

The aim was to evaluate the prevalence of delirium among patients discharged from an acute care hospital and admitted to a geriatric convalescence unit (GCU), and to analyze patient's characteristics and risk precipitating factors. Sixty-eight patients were analyzed during a 2-week period. The confusion assessment method (CAM) was used to detect delirium. The precipitating factors evaluated were: major surgery-intensive care unit(ICU) stay, pulmonary and heart failure, acute infections, metabolic disorders/anemia,psychoactive medications, other drugs, severe pain, changing environmental influences and others. According to CAM, fifteen patients presented delirium (22%), and in 14 of them(93.3 %) the delirium was developed before admission at GCU. The precipitating factors in the studied population were the following: changing environmental influences in 66 patients(97%) (15 with delirium and 51 without delirium); other drugs 56 (82.3 %) (11 vs. 45);others 56 (82.3%) (9 vs. 24); psychoactive medications 50 (73.5%) (12 vs. 38); acute infections 48 (70.5 %) (13 vs. 35); metabolic disorders/anemia 40 (58.8 %) (9 vs. 31); major surgery-ICU stay 28 (41 .1%) (8 vs. 20); severe pain 26 (38.2%) (6 vs. 20); pulmonary and heart failure 22 (32.3%) (5 vs. 17). The univariant analysis showed that, none of the precipitating factors studied was significantly related to delirium. Seventy-two patients (91.1%) had simultaneously >3 precipitating factors. There were 16 patients with >6 precipitating factors, 7 of 15 with delirium and 9 of the 53 without delirium (46.6 % vs 16.9 %) (p < 0.05). The prevalence of delirium has been 22 %. Most of the patients had developed delirium before the admission at GCU. A high proportion of patients had >3 precipitating factors. In the study the presence of > 6 precipitating factors simultaneously has been significantly related to delirium.

Validation of a modified version of the Gijon's social-familial evaluation scale (SFES): the "Barcelona SFES Version", for patients with cognitive impairment

The aim was to validate an abbreviated version of the Gijon's social-familial evaluation scale (SFES) (Barcelona-SFES version), on patients with cognitive impairment. A group of 34 patients with cognitive impairment, admitted to an intermediate-long-term-care facility, were analyzed. Mean age was 80.2 +/- 7.4 years. Gijón's SFES was abbreviated and only the first three item groups corresponding to family conditions, social contacts and assistance from the social network were selected. Barcelona-SFES version had a range score between 3 to 15 points, in which low scores identify older patients who live with their family, have good contacts, and participate in community activities. In contrast, high scores identify older persons who live alone and have poor social support and little participation with community activities. Three social risk categories were established according to the Barcelona-SFES score: low social risk (>/= 7 points), intermediate social risk (8-9 points) and high social points). Validation criteria used in the present study were: predictive value of Barcelona-SFES score of post-discharge destination (home or institution), and patient's (or family's) request for a definitive institutionalization in a nursing home. There were 9 patients with low social risk (26.4 %), 8 with intermediate social risk (23.5 %) and 17 with high social risk (50 %). A significant relationship between Barcelona-SFES scores and post-discharge destination was found. Eighty percent of patients discharged to an institution(nursing and residential homes), they had high social risk SFES scores (>/= 10) Also, a significant correlation was found between the number of patients for which a definitive institutionalization request was performed and the Barcelona-SFES scores. Fifteen (88.2 %) of the 18 patients for whom the request was done, were in the high social risk group. The lowest scores from SFES were predictive of home discharge, while the highest scores were predictive of a definitive institutionalization.

PREVIOUS COGNITIVE IMPAIRMENT AND FAILURE TO THRIVE SYNDROME IN PATIENTS WHO DIED IN A GERIATRIC CONVALESCENCE HOSPITALIZATION UNIT

Cognitive impairment and depression are commonly associated with poor outcomes in geriatric patients. Both are part of the "failure to thrive syndrome" (FTS), that is a combined group of symptoms as a result from progressive functional, mental and nutritional impairment status in older patients. This paper was aimed at evaluating the presence of FTS in the patients who died in a geriatric convalescence unit (GCU) (intermediate care facility) and comparing the characteristics of patients with primary FTS (not associated with an evident identifiable disease) and secondary FTS (associated with an evident identifiable disease). Finally, we wanted to analyze if the presence of cognitive impairment before admission was associated with the type of FTS. We analyzed 78 patients retrospectively. The presence of the next three conditions was necessary to define the FTS: (i) Impaired functional status and malnutrition. (ii) Cognitive impairment and/or depression. (iii) Absence of improvement, after a specific geriatric intervention program during the hospitalization. Functional status for basic and instrumental activities of daily living (ADL and IADL) and the presence of symptoms cognitive impairment before admission were evaluated. Of the 78 analyzed patients, there were 30 (38.4%) with symptoms of FTS. Seventeen of them (56.6%) had a secondary FTS and 13 (43.3%) a primary one. This last group of patients had a significantly higher mean age (84.7 +/- 5.8 vs. 78.6 +/- 7.2; p < 0.02) and before admission they were significantly more dependent for ADL: 10 patients (76.9%) vs. 7 (41.0%) chi2 = 3.833, p < 0.05. A higher proportion of subjects with cognitive impairment before admission was found in the group of patients with primary FTS, than in those secondary FTS, although this difference did not reach statistical significance. Patients with primary FTS seem to be older and more dependent for ADL before admission, than those with secondary FTS.

OBSERVATIONAL SCALE AND GERIATRIC DEPRESSION SCALE OF YESAVAGE TO IDENTIFY DEPRESSIVE SYMPTOMS IN OLDER PATIENTS

The diagnosis of depression by clinical interview may be difficult in the patients with communication problems (aphasia, severe cognitive impairment or severe deafness). In these cases, depressive symptoms may be observed by others (nurses and caregivers). The aim of this study was to evaluate the clinical usefulness of an observational scale to identify depression in older patients. Seventy-six institutionalized patients in an intermediate-long-term care center were evaluated. Of them, 39 were excluded because they were unable to perform a clinical interview, needed to diagnose depression. Of the excluded patients, 18 had aphasia, 7 showed severe cognitive impairment: their mini mental state examination (MMSE) score < 14, and 14 collaborated very poorly. Thus 37 patients were analyzed, mean age was 83 +/- 0.86 years (30 women and 7 men). Diagnostic categories were: neurological 16 patients (43.2%), fractures/orthopedics 6 (16.2%), pulmonary/cardiology 5 (13.5%) and others 10 (27.1%). The mean Barthel index was 57.0 +/- 31.6 and mean MMSE score was 21.1 +/- 4.3. The observational scale (OS) designed with six items, was applied to all patients. Each item was scored as never (0 points), sometimes (1 point) and always (2 points). Thus total OS score ranged from 0 to 12. Two observers, who knew the patients (nurses), applied the OS. A trained geriatrician, using the 15-item geriatric depression scale (GDS) performed detection of depressive symptoms. There were 15 patients (40.5 %) with depression on the GDS. OS scale score with a cutoff point of 5 or more was present in 13 patients; nine of them had depression (69.2 %). In the remaining 24 patients with an OS score < 5, depression was present only in 6 cases (25%) (chi2 = 6.844; p < 0.01). The OS >/= 5, in the present study, obtained a sensitivity of 60 %, a specificity of 81 %, a positive predictive value of 69 %, and a negative predictive value of 75 %.We concluded that (i) the OS has been useful for identifying depressive symptoms with an acceptable sensitivity and specificity, and (ii) the OS may be an alternative to detect depression in patients who are unable to perform a clinical interview.

CLINICAL IMPACT OF DIFFERENT SCORES OF THE MINI NUTRITIONAL ASSESSMENT (MNA) IN THE DIAGNOSIS OF MALNUTRITION IN PATIENTS WITH COGNITIVE IMPAIRMENT

It was aimed at evaluating the clinical usefulness of the mini nutritional assessment (MNA) to identify malnutrition in elderly patients with cognitive impairment, admitted to a geriatric convalescence unit (intermediate care facility). Sixty-three patients with cognitive impairment were studied. Cognitive impairment was considered when mini mental state examination (MMSE) scores were below 21. MNA and a nutritional evaluation according to the sequential model of the American Institute of Nutrition (AIN) were performed at admission. According to the AIN criteria, malnutrition was considered, if there were abnormalities in at least one of the following parameters: albumin, cholesterol, body mass index (BMI), and branchial circumference. Based on these criteria, 27 patients (42.8%) proved to be undernourished at admission, whereas if taking the original MNA scores, 39 patients (61.9%) were undernourished, 23 (36.5%) were at risk of malnutrition, and 1 (1.5%) was normal. The analyzed population was divided in four categories (quartiles) of the MNA scores: very low (</= 13.5), low (> 13.5 and </= 16), intermediate (> 16 and </= 18.5) and high (> 18.5). Likelihood ratios of each MNA quartile were obtained by dividing the percentage of patients in a given MNA category who were undernourished (according to AIN) by the percentage of patients in the same MNA category who were not undernourished. In the very low MNA quartile, this likelihood ratio was 2.79 and for the low MNA quartile it was 0.49. For intermediate and high MNA categories, likelihood ratios were 1.0 and 0.07 respectively. In the present study, MNA identified undernourished patients with a high clinical diagnostic impact value only, when very low scores (</= 13) are obtained.

[A ketogenic diet: is this a valid alternative in refractory epilepsy]

INTRODUCTION

The ketogenic diet was first used in refractory epilepsy of childhood in the early 1920s. It was forgotten when new antiepileptic drugs were introduced, but recently has been used again. Although its efficacy in the treatment of epilepsy, in some patients, is beyond doubt, its mechanism of action is still not clear. There are three types of diet: the classical diet with a proportion of 4:1 of long chain fatty acids, with MCT oil and with modified MCT oil.

OBJECTIVE

To present a protocol recently designed in our hospital. We include the type of diet, form of onset, subsequent follow up of complications, clinical and electroencephalographic response and side effects seen in the patients.

PATIENTS AND METHODS

Introduction of the ketogenic diet with MCT oil in six patients aged between 2 and 11 years, with various types of epilepsy, all resistant to treatment, who had been unsuccessfully treated for 28 months in one case and between 4 and 6 months in the others. We evaluated the response on the criteria of Huttenlocher and Panic electroencephalograms.

RESULTS

Two of the patients improved with good control of their disorder and the EEG became normal. No serious side effects were seen apart from gastrointestinal symptoms which improved when the quantity of MCT oil was reduced.

CONCLUSIONS

In patients with drug resistant epilepsy it is convenient to have a guideline for treatment using a ketogenic diet. It is also useful to have a multi disciplinary team for management, follow up to detect late side effects and obtain the cooperation of the patient s family in following the protocol.

Schizosaccharomyces pombe rho2p GTPase regulates cell wall alpha-glucan biosynthesis through the protein kinase pck2p

Schizosaccharomyces pombe rho1(+) and rho2(+) genes are involved in the control of cell morphogenesis, cell integrity, and polarization of the actin cytoskeleton. Although both GTPases interact with each of the two S. pombe protein kinase C homologues, Pck1p and Pck2p, their functions are distinct from each other. It is known that Rho1p regulates (1,3)beta-D-glucan synthesis both directly and through Pck2p. In this paper, we have investigated Rho2p signaling and show that pck2 delta and rho2 delta strains display similar defects with regard to cell wall integrity, indicating that they might be in the same signaling pathway. We also show that Rho2 GTPase regulates the synthesis of alpha-D-glucan, the other main structural polymer of the S. pombe cell wall, primarily through Pck2p. Although overexpression of rho2(+) in wild-type or pck1 delta cells is lethal and causes morphological alterations, actin depolarization, and an increase in alpha-D-glucan biosynthesis, all of these effects are suppressed in a pck2 delta strain. In addition, genetic interactions suggest that Rho2p and Pck2p are important for the regulation of Mok1p, the major (1-3)alpha-D-glucan synthase. Thus, a rho2 delta mutation, like pck2 delta, is synthetically lethal with mok1-664, and the mutant partially fails to localize Mok1p to the growing areas. Moreover, overexpression of mok1(+) in rho2 delta cells causes a lethal phenotype that is completely different from that of mok1(+) overexpression in wild-type cells, and the increase in alpha-glucan is considerably lower. Taken together, all of these results indicate the presence of a signaling pathway regulating alpha-glucan biosynthesis in which the Rho2p GTPase activates Pck2p, and this kinase in turn controls Mok1p.

Fusobacterium nucleatum involvement in adult periodontitis and possible modification of strain classification

BACKGROUND

This investigation was designed to evaluate the involvement of Fusobacterium nucleatum clinical strains in adult periodontitis by subspecies and expression of hemagglutination activity.

METHODS

Forty-nine Fusobacterium strains were isolated from 40 sites in 40 subjects presenting with adult periodontitis. F. nucleatum subspecies identification was based on the electrophoretic migration of glutamate dehydrogenase and 2-oxoglutarate reductase. Hemagglutination activity and inhibition by galactose were tested on sheep erythrocytes.

RESULTS

The 49 isolates belonged to the F. nucleatum species with a predominance of the nucleatum (34.7%) followed by the vincentii (26.5%) subspecies. In parallel, 71% of the strains belonging to the nucleatum subspecies were preferentially associated with Porphyromonas gingivalis. Prevotella intermedia/nigrescens detection was essentially correlated with identification of Fusobacterium nucleatum subspecies vincentii. No correlation was established between any particular subspecies and the pathogenicity factors tested (hemagglutination and production of short-chain fatty acids). On the other hand, significant predominance (65%, P= 0.017) of strongly hemagglutinating strains (titre > or =8 U) was observed in the sites where Porphyromonas gingivalis, Prevotella intermedia/nigrescens and/or Campylobacter rectus were not detected. These strains also showed higher butyric acid production.

CONCLUSION

The importance of the adherence factors for Fusobacterium nucleatum strains and their multimodal aspect may indicate a higher pathogenicity or a higher involvement of certain strains and could lead to a classification of these strains, which is more closely related to their implication in the development of periodontal disease.

Routine analysis of short-chain fatty acids for anaerobic bacteria identification using capillary electrophoresis and indirect ultraviolet detection

The diagnosis of anaerobes can be difficult to perform, using classical biochemical tests. Characterization of metabolic end-products such as short-chain fatty acids (SCFA) was often used because of their reproducible biosynthesis. Despite this, SCFA are difficult to study using gas chromatography, due to their high volatility. Furthermore, the treatment of the samples are long and fastidious. Capillary electrophoresis and indirect UV detection (CE-indirect UV) is a well-known analytical method to study inorganic or organic anions. In this work, we validate the analysis of SCFA using CE-indirect UV detection. To do this, we studied the culture media of 98 anaerobic strains for the detection and quantitation of the following acids: succinic, pyruvic, acetic, lactic, propionic, 2-hydroxybutyric, butyric, 2-hydroxyvaleric, isovaleric, isocaproic, and 3-phenylpropionic. We verified that the CE-indirect UV detection analysis of SCFA for taxonomical data can be used as a mean for rapid identification for the study of anaerobes.

Proper ascospore maturation requires the chs1+ chitin synthase gene in Schizosaccharomyces pombe

We have cloned chs1+, a Schizosaccharomyces pombe gene with similarity to class II chitin synthases, and have shown that it is responsible for chitin synthase activity present in cell extracts from this organism. Analysis of this activity reveals that it behaves like chitin synthases from other fungi, although with specific biochemical characteristics. Deletion or overexpression of this gene does not lead to any apparent defect during vegetative growth. In contrast, chs1+ expression increases significantly during sporulation, and this is accompanied by an increase in chitin synthase activity. In addition, spore formation is severely affected when both parental strains carry a chs1 deletion, as a result of a defect in the synthesis of the ascospore cell wall. Finally, we show that wild-type, but not chs1-/chs1-, ascospore cell walls bind wheatgerm agglutinin. Our results clearly suggest the existence of a relationship between chs1+, chitin synthesis and ascospore maturation in S. pombe.