Clonal selection in the bone marrow involvement of follicular lymphoma

To characterize the pathways of bone marrow (BM) involvement of follicular lymphoma (FL), we performed morphological and immunophenotypical analysis of tumor cells from lymph nodes (LNs) and corresponding BMs in 21 patients with FL. In three cases, genealogical trees were constructed based on the immunoglobulin variable region heavy chain (IgV(H)) gene sequences of tumor clones from LNs and BMs. Results showed that FLs within the BMs display identical or lower cytological grades than in the LNs. In the majority of cases, different proportions of tumor cells expressed bcl-2, CD10 and Ki67 in LNs and BMs. Tumor cells in the BM showed ongoing somatic hypermutation of the IgV(H) genes; the distribution of these mutations was highly consistent with antigen selection. The topology of the genealogical trees revealed that different subclones populate the LN and BM and BM infiltration may occur at different points of the clonal evolution of FL. Early descendants of the original tumor clone and derivatives of diversified tumor clones may invade the BM. These results suggest that the BM involvement of FL is associated with intensive clonal selection of tumor cells, and the BM provides a microenvironment similar to the germinal centers of LNs, where tumor cells retain their biological nature.

Aberrant somatic hypermutation and expression of activation-induced cytidine deaminase mRNA in mediastinal large B-cell lymphoma

To determine the possible role of aberrant somatic hypermutation (ASHM) and activation-induced cytidine deaminase (AID) expression in the pathogenesis of mediastinal large B-cell lymphoma (MBL), the mutational status of genes affected by ASHM, including c-MYC, PAX-5 and RhoH, was analysed, and the expression level of AID mRNA in tumour specimens from six patients with MBL was determined. Mutations in one or more genes and high expression of AID mRNA were detected in all the six cases of MBL. These results suggest that ASHM and AID expression may have a role in the pathogenesis of MBL.

DNA content heterogeneity in neuroblastoma analyzed by means of image cytometry and its potential significance

The aim of this study was to determine the frequency and significance of the tumor DNA content heterogeneity in 33 previously untreated human neuroblastomas. We used image cytometry to selectively analyze neuroblasts by excluding karyorrhectic or stromal cells from cytometric measurements. DNA content heterogeneity with more than one clonal subpopulation on DNA histogram was found in 8 of 33 cases. Of these 8 cases, 4 showed MYCN amplification. Double labeling fluorescent in situ hybridization with probes for the centromeric region of chromosome 2 and MYCN gene was used to confirm the DNA content heterogeneity. DNA content heterogeneity was associated with poorer prognosis in this study (P<0.05). There was a significant correlation between euploidy (di- and tetraploidy) and worse prognosis, but only when heterogeneous neuroblastomas with euploid cell population were assigned to euploid tumors (P=0.006). Our results may explain the conflicting data in the literature regarding ploidy and suggest that DNA content heterogeneity and the presence of a euploid population may predict worse prognosis in neuroblastoma patients.

Human papillomavirus in head and neck cancer: Molecular biology and clinicopathological correlations

Human papillomaviruses are known to cause cancers of the cervix and other anogenital tract sites. Epidemiologic and molecular pathology studies have also suggested that HPV infection may be associated with cancers of the head and neck. Modes of transmission of HPV infection in the head and neck region have not been fully resolved; however, perinatal transmission and an association between sexual behavior and risk for HPV-positive cancers have been presented. Among the HPV types infecting the mucosa, high-risk, intermediate-risk and low-risk genotypes are defined, depending on their presence in carcinoma or precursor lesions. The phylogenic groups of HPVs also showed a definite correlation with the morphology of head and neck tumors. The groups A6, A7, and A9 include viruses that are frequently demonstrated in basaloid and verrucosus squamous cell carcinomas known to associate with HPV infection. Integration of HPV DNA into the host cell genome occurs early in cancer development and is an important event in malignant transformation. There is a trend for patients with HPV-positive tumors to be nondrinkers or light drinkers, the majority of these patients are females, and the median age is lower than in the case of HPV-negative tumors, but this latter difference was not always statistically significant. In the Kaplan-Meier survival model, the HPV-positive verrucous and basaloid squamous cell carcinomas showed better survival rates than the HPV-negative typical squamous cell carcinomas. An increased radiocurability of HPV-positive head and neck squamous cell carcinoma (HNSCC) has also been demonstrated.

Synthesis and complexation properties of DTPA-N,N″-bis[bis(n-butyl)]-N′-methyl-tris(amide). Kinetic stability and water exchange of its Gd3+complex

A novel DTPA-tris(amide) derivative ligand, DTPA-N,N''-bis[bis(n-butyl)]-N'-methyl-tris(amide)(H2L3) was synthesized. With Gd3+, it forms a positively charged [Gd(L3)]+ complex, whereas with Cu2+ and Zn2+ [ML3], [MHL3]+ and [M2L3]2+ species are formed. The protonation constants of H2L3 and the stability constants of the complexes were determined by pH potentiometry. The stability constants are lower than those for DTPA-N,N''-bis[bis(n-butyl)amide)](H3L2), due to the lower negative charge and reduced basicity of the amine nitrogens in (L3)2-. The kinetic stability of [Gd(L3)]+ was characterised by the rates of metal exchange reactions with Eu3+, Cu2+ and Zn2+. The exchange reactions, which occur via proton and metal ion assisted dissociation of [Gd(L3)]+, are significantly slower than for [Gd(DTPA)]2-, since the amide groups cannot be protonated and interact only weakly with the attacking metal ions. The relaxivities of [Gd(L2)] and [Gd(L3)]+ are constant between 10-20 degrees C, indicating a relatively slow water exchange. Above 25 degrees C, the relaxivities decrease, similarly to other Gd3+ DTPA-bis(amide) complexes. The pH dependence of the relaxivities for [Gd(L3)]+ shows a minimum at pH approximately 9, thus differs from the behaviour of Gd3+-DTPA-bis(amides) which have constant relaxivities at pH 3-8 and an increase below and above. The water exchange rates for [Gd(L2)(H2O)] and [Gd(L3)(H2O)]+, determined from a variable temperature (17)O NMR study, are lower than that for [Gd(DTPA)(H2O)]2-. This is a consequence of the lower negative charge and decreased steric crowding at the water binding site in amides as compared to carboxylate analogues. Substitution of the third acetate of DTPA5- with an amide, however, results in a less pronounced decrease in kex than substitution of the first two acetates. The activation volumes derived from a variable pressure (17)O NMR study prove a dissociative interchange and a limiting dissociative mechanism for [Gd(L2)(H2O)] and [Gd(L3)(H2O)]+, respectively.

Superparamagnetic gadonanotubes are high-performance MRI contrast agents

We report the nanoscale loading and confinement of aquated Gd3+n-ion clusters within ultra-short single-walled carbon nanotubes (US-tubes); these Gd3+n@US-tube species are linear superparamagnetic molecular magnets with Magnetic Resonance Imaging (MRI) efficacies 40 to 90 times larger than any Gd3+-based contrast agent (CA) in current clinical use.

[Treatment of primary mediastinal large B-cell lymphomas]

INTRODUCTION

Primary mediastinal large B-cell non-Hodgkin's lymphoma is a relatively rare disease with specific clinical symptoms. This tumour originates from a subset of B-cells of the thymus and at the time of the diagnosis the disease is predominantly localised in the mediastinum. The tumor grows rapidly and frequently involves other thoracic structures. The majority of the patients are young females. There are no histologic features that reliably distinguish these tumors from other diffuse large B-cell lymphomas. This is the only lymphoma subtype which can only be defined by the combination of clinical and pathologic features. Analysis with DNA microarrays verified that primary mediastinal and diffuse large B-cell lymphomas are different diseases.

AIMS

Comparing the effectiveness of two types of anthracycline-based standard chemotherapy regimens and the evaluation of the prognostic markers which are applied in large B-cell lymphomas.

METHODS

27 patients with primary mediastinal lymphoma were treated by the authors with anthracycline-based polychemotherapy with complementary radiotherapy from January 1995 to December 2002.

RESULTS

Complete remission was obtained in 15 patients (56%) and no relapse was observed in this group. 9 additional patients (33%) achieved partial remission, while in 3 cases (11%) the treatment was ineffective. The patients who failed to achieve complete remission were subsequently treated with more intensive chemotherapy. Afterwards, those patients who were chemosensitive, underwent high-dose chemotherapy with autologous peripheral blood stem-cell transplantation. The chemoresistant patients received palliative chemotherapy. The 5-year overall survival rate of the 27 patients was 62.11%.

CONCLUSION

The authors found that the procarbazine, prednisolone, adriamycin, cyclophosphamide, etoposide, cytosine-arabinoside, bleomycin, vincristine, methotrexate treatment was more effective than the cyclophosphamide, adriamycin, vincristine, prednisolone combination. The expected 5-year overall survival rates were 83.57% vs. 33.33%, respectively. This difference was significant (p = 0.017). No prognostic value of age adjusted international prognostic index, LDH- and b2-microglobulin levels were found. The results with the new standard of combined immuno-chemotherapy (rituximab--cyclophosphamide, adriamycin, vincristine, prednisolone) seem to be hopeful and more effective than earlier treatments.

Effects of sweet and bitter gustatory stimuli in anorexia nervosa on EEG frequency spectra

The possible differences in processing gustatory stimuli in anorexic patients compared to healthy control subjects was investigated by electrophysiological methods. The electroencephalogram (EEG) was recorded in outpatients treated with anorexia nervosa (AN) and age-matched controls after exposure to sweet (milk chocolate) and bitter (black tea) taste stimuli. Power spectrum analysis was performed on EEG epochs recorded in the above conditions. Compared to controls a significantly higher percent of theta, and lower percent of alpha1 band power was found in anorexic patients, irrespective of the kind of taste effects and hemispheric side. The pattern of activation caused by sweet and bitter stimuli was found to be different in these two groups, possibly indicating altered gustatory processing mechanisms in AN.

Nonlinear and linear EEG complexity changes caused by gustatory stimuli in anorexia nervosa

The objective of the present study was to investigate the effects of pleasant and unpleasant gustatory stimuli on nonlinear and linear complexity measures of the EEG in healthy controls and in anorexia nervosa (AN) patients. The subjects were exposed to unpleasant (bitter tea) and pleasant (chocolate) gustatory stimuli for 2 min. Multichannel EEG was recorded and the dimensional complexity (point-correlation dimension) and Omega complexity were calculated from the EEG epochs corresponding to the above taste conditions. In AN patients lower-dimensional complexity was observed in the majority of recording sites than that seen in controls, independent of taste conditions. Higher Omega complexity was seen in control subjects in the left side irrespective of taste effects. No such hemispheric difference was observed in AN. The lower-dimensional complexity seen in AN patients may be caused by long-lasting effects of malnutrition. The lack of a significant Omega complexity change in response to exposure of sweet taste in the left side seen in AN patients may correspond to a decreased sensitivity to such stimuli in these subjects.

Oxidative stress-induced dysregulation of arteriolar wall shear stress and blood pressure in hyperhomocysteinemia is prevented by chronic vitamin C treatment

We aimed to test the hypothesis that an enhanced level of reactive oxygen species (ROS) is primarily responsible for the impairment of nitric oxide (NO)-mediated regulation of arteriolar wall shear stress (WSS) in hyperhomocysteinemia (HHcy). Thus flow/WSS-induced dilations of pressurized gracilis muscle arterioles (basal diameter: approximately 170 microm) isolated from control (serum Hcy: 6 +/- 1 microM), methionine diet-induced HHcy rats (4 wk, serum Hcy: 30 +/- 6 microM), and HHcy rats treated with vitamin C, a known antioxidant (4 wk, 150 mg. kg body wt-1.day-1; serum Hcy: 32 +/- 10 microM), were investigated. In vessels of HHcy rats, increases in intraluminal flow/WSS-induced dilations were converted to constrictions. Constrictions were unaffected by inhibition of NO synthesis by N omega-nitro-L-arginine methyl ester (L-NAME). Vitamin C treatment of HHcy rats reversed the WSS-induced arteriolar constrictions to L-NAME-sensitive dilations but did not affect control responses. Similar changes in responses were obtained for the calcium ionophore A-23187. In addition, diastolic and mean arterial blood pressure and serum 8-isoprostane levels (a marker of in vivo oxidative stress) were significantly elevated in rats with HHcy, changes that were normalized by vitamin C treatment. Taken together, our data show that in chronic HHcy long-term vitamin C treatment, by decreasing oxidative stress in vivo, enhanced NO bioavailability, restored the regulation of shear stress in arterioles, and normalized systemic blood pressure. Thus our study provides evidence that oxidative stress is an important in vivo mechanism that is primarily responsible for the development of endothelial dysregulation of WSS in HHcy.

Detection of n-myc gene amplification in neuroblastoma by comparative, in situ,and real-time polymerase chain reaction

We have used semiquantitative comparative and real-time quantitative polymerase chain reactions (PCR) to detect n-myc gene-amplification in 20 frozen neuroblastoma biopsies and IMR 32 cell line to predict biological behavior of the tumors. Two primer pairs were used for the semiquantitative method to co-amplify a 520-bp fragment of the beta-globin gene--used as a single copy reference standard--and a 258-bp fragment of the n-myc gene. After 30 cycles the PCR products were electrophoresed through an agarose gel and were compared to each other with use of a gel-densitometer. Real-time quantitative analyses were performed in a LightCycler instrument. A single primer pair was used to amplify a 120-bp fragment of the n-myc oncogene and a LC640-labeled fluorescent probe pair to detect the product. Calibration curve, set up from a serial dilution including samples with 1, 2, 10, 13, 25-fold n-myc oncogene amplification, was used for quantitative analysis. The semiquantitative method did not show distinct difference between tumor groups with no amplification and less than 10-fold amplification, whereas quantitative LightCycler analysis was able to detect even 2-fold amplification. Differentiated neuroblastomas seldom show n-myc amplification. In spite of this, we have found two partly differentiated tumor samples that contained n-myc amplification. In these cases in situ PCRs were performed to examine the tumor heterogeneity. We used biotinated ATP labeling and the same primer pair as for the LightCycler analysis. In both cases differentiated cells did not show n-myc gene amplification, whereas considerable amplification was detected in the neuroblasts.

Pannonibacter phragmitetus gen. nov., sp. nov., a novel alkalitolerant bacterium isolated from decomposing reed rhizomes in a Hungarian soda lake

Three alkalitolerant bacterial strains were isolated from the surface of decomposing rhizomes of reed [Phragmites australia (Cav.) Trin. et Steudel] in Lake Fertö (Hungary). Cells of the novel isolates were Gram-negative, motile rods and formed star-shaped aggregates. They were facultatively anaerobic and chemo-organotrophic. Bacteriochlorophyll a was not synthesized under aerobic conditions. The strains were catalase and oxidase positive, produced acid from D-glucose under aerobic and anaerobic conditions and reduced nitrate to nitrogen. They tolerated pH values from 7.0 to 11.0 and grew in the absence of NaCl as well as in up to 5% (w/v) NaCl. The G + C content of the DNA was 64.6 mol% and the major isoprenoid quinone was Q-10. The dominant cellular fatty acid was C18 : 1omega7c. The cell membrane contained phosphatidyl glycerol, diphosphatidyl glycerol, phosphatidyl ethanolamine, phosphatidyl serine and one unknown phospholipid as polar lipids. Polyphasic taxonomic characterization revealed that strain C6/19T is most closely related to the Stappia-Roseibium cluster in the alpha-subclass of the Proteobacteria (showing 95.8-93.6% 16S rDNA sequence similarity). According to the phylogenetic and phenotypic evidence presented, a new genus and species is proposed, Pannonibacter phragmitetus gen. nov., sp. nov. The type strain is C6/19T (=DSM 14782T =NCAIM B02025T).

Prediction of cervical infiltration in Stage II endometrial cancer by different preoperative evaluation techniques (D&C, US, CT, MRI)

OBJECTIVE

Our clinical practice for FIGO Stage II endometrial cancer consists of Wertheim's radical hysterectomy as first choice of treatment. The evaluation of patients is based on D&C. The accuracy of this preoperative staging method is examined here.

METHODS

Twenty-nine patients with endometrial cancer with suspected cervical involvement (FIGO Stage II) based on endocervical curettage underwent Wertheim's radical hysterectomy between January 1, 1989 and December 31, 2001 at the Gynaecological Department of the National Institute of Cancer, Budapest, Hungary. In all cases surgico-pathological staging was performed to examine the accuracy of preoperative D&C and to find out whether radical surgery was necessary in all patients and how the preoperative evaluation of patients should be improved.

RESULTS

Out of 29 patients who underwent Wertheim's hysterectomy the pathological examination found primary cervical cancer in two patients. These two patients were eliminated from further evaluation. Out of the remaining 27 patients only eight (29.6%) had cervical involvement of endometrial cancer documented by a pathologic review on the hysterectomy specimen. Extrauterine disease was documented in one of the patients with cervical infiltration (1/8) and in one in the cervix-negative group (1/19). Ovarian spread was found in the first case and ovarian infiltration with penetration of the tumour into the parametric tissue in the second case. According to the FIGO classification 18 (66.6%) patients had less extensive disease and two (7.4%) had more extensive disease. Only 26% of the patients (7/27) had surgical findings consistent with the Stage II disease.

CONCLUSION

We can conclude that "overtreatment" seems to have occurred in 19 patients, whose cervical infiltration by endometrial cancer could not be proved by pathological staging. It can also be assessed that understaging took place in two cases, which can be explained by two reasons; we did not make use of preoperative imaging techniques since US was applied in six patients, CT in 16 and the most accurate, MRI, on three patients only. The other possible reason, which can point out the bad efficacy of the imaging techniques as well, could be that a major part of the patients received preoperative AL treatment, which could also have influenced the cervical progression. This is possible, but has not been proved. The difference in the number of cervical infiltrations in the group of patients who received preoperative radiotherapy and in the group where they did not, is not significant (p = 0.9742), and infiltration of the endometrium was present in all cases. In the future, proper selection of imaging modalities can improve the staging of gynaecological disorders and preclude unnecessary procedures. In endometrial cancer cases US, especially with the use of TVUS, is often considered to be the primary imaging approach. However, in patients where ultrasound is suboptimal, where there is a large tumour present or the result of imaging studies will directly influence the choice of therapy and guide therapy planning then the higher accuracy of MRI warrants its use. CT is of use in the later stages of disease; differentiation between Stage I and II is difficult and CT is limited in the assessment of myometrial invasion.

[Endometrial cancer in a young woman taking oral contraceptives for a long time]

The authors report a rare case of endometrial adenocarcinoma occurred in a 35-year old woman, who had taken oral contraceptives for 13 years. She came for consultation with irregular vaginal bleeding. Diagnostic curettage and histologic examination confirmed the diagnosis as endometrial adenocarcinoma. This case deserve special attention due to the rarity of the disease among young women. The authors emphasize the necessity of appropriate diagnostic work-up. In such cases histological examination is strongly recommended, since irregular vaginal bleeding might be caused by malignant disease even at young women using sequential oral contraceptives.

The value of ECG and echocardiography during stress testing for identifying systemic endothelial dysfunction and epicardial artery stenosis

BACKGROUND

In the stress imaging era, ECG positivity is regarded as a frequent source of false-positive responses. However, it is known that normal coronary arteries frequently coexist with abnormal endothelial function in patients with chest pain.

AIM

To evaluate the anatomical coronary epicardial, and functional systemic endothelial determinants of wall motion and electrocardiographic responses during stress testing.

METHOD

Sixty-eight in-hospital patients with chest pain syndrome, no previous myocardial infarction, and off nitrate therapy at the time of testing underwent, on different days, in random order and within 1 month: (1) stress ECG echo testing (with dipyridamole in 43, dobutamine in 3, and exercise in 22 patients); (2) coronary angiography; (3) endothelium-dependent, flow-mediated dilation of the brachial artery during reactive hyperaemia using high-resolution ultrasound. Criteria of positivity were: ST segment depression >0.1mm in the stress ECG; regional dysfunction >2 segments demonstrated by stress-echo; diameter reduction >50% on coronary angiography; and <5% flow-mediated dilation as revealed by endothelial function.

RESULTS

Significant coronary artery disease was present in 39 patients, and was predicted on multivariate analysis by stress-induced wall motion abnormalities (OR=108.8; 95% CI=8.5-1,389.4, P=0.0003), but not by either ST segment depression (P=0.13; OR=0.47; 95% CI=0.7-1.3) or reduced flow-mediated dilation (P=0.81; OR=0.87; 95% CI=0.27-2.8). Abnormal flow-mediated dilation was present in 53 patients (78%), and was predicted by stress-induced ST segment depression (P=0.023; OR=6.2; 95% CI=1.3-30.5), but not by either stress echo positivity (P=0.66; OR=0.77; 95% CI=0.23 to 2.5) or angiographically assessed coronary artery disease. There was no correlation between flow-mediated dilation and extent of coronary artery disease as assessed by the angiographic Duke score (from 0=normal to 100=most severe disease): r=-0.13, P=0.91.

CONCLUSION

Epicardial coronary artery anatomy affects wall motion abnormalities, and systemic endothelial dysfunction affects ST segment depression during stress. However, echocardiographic positivity is unrelated to endothelial dysfunction, and electrocardiographic positivity is an inaccurate predictor of coronary stenosis. An integration of ECG and functional markers is warranted in the stress testing lab.

Flat and depressed colorectal tumours in a southern Swedish population: a prospective chromoendoscopic and histopathological study

BACKGROUND

Flat and depressed colorectal tumours are common in Japan but are very rare or non-existent in Western countries.

AIMS

To study the occurrence of flat colorectal tumours in a southern Swedish population.

METHODS

In this prospective study, 371 consecutive European patients were examined by high resolution video colonoscopy combined with chromoendoscopy. The nature of the lesions was determined by histopathological examination.

RESULTS

A total of 973 tumours were found; 907 (93.2%) were protruding and 66 (6.8%) were flat or depressed. Of the flat/depressed tumours, five (7.7%) were early adenocarcinomas infiltrating the submucosa. Eleven carcinomas (1.2%) were found among protruding tumours. High grade dysplasia was observed in 18% (n=11) of flat/depressed adenomas in contrast with 7.3% (n=65) of protruding adenomas, and occurred in smaller flat/depressed tumours compared with protruding ones (mean diameter 8 mm v 23 mm, respectively). Furthermore, high grade dysplasia was significantly more common in flat elevated tumours with central depression or in depressed adenomas (35.7%; 5/14) than in flat elevated adenomas (12.8%; 6/47).

CONCLUSION

Flat and depressed tumours exist in a Western population. Future studies should address whether or not chromoendoscopy with video colonoscopy is necessary in the search for flat colorectal neoplasms.

Complex pathological diagnosis of granulocytic sarcoma: apropos of a case

The diagnosis of granulocytic sarcoma can be very difficult when there is no demonstrable abnormality in the peripheral blood or bone marrow. We present the diagnostic algorithm of granulocytic sarcoma by reporting on a case mimicking large cell lymphoma without previous manifestation of acute myeloid leukemia or a myeloproliferative disorder. After standard histoprocessing, we used immunohistochemical and molecular biological methods to analyze our case. The lymph node showed diffuse infiltration of immature blast cells resembling large cell lymphoma. However, immunohistochemistry did not support this diagnosis. The tumor cells showed LCA, bcl-2, CD43, CD34 and myeloperoxidase positivity. We also detected bcl-2 gene rearrangement. In case of a lack of a specific histological picture, particularly in poorly differentiated tumors, only some minor histological signs in combination with immunohistochemistry and molecular diagnostic methods can help to render the correct diagnosis.

Thermobifida cellulolytica sp. nov., a novel lignocellulose-decomposing actinomycete

Four actinomycete strains, isolated from the overheated region of manure compost, were assigned to the genus Thermobifida on the basis of morphological, physiological and biochemical characteristics. All strains produced single, ovoid, heat-sensitive spores on dichotomically branched aerial hyphae. On the basis of chemotaxonomic traits, these isolates showed strong affinity towards members of the genus Thermobifida. Cell-wall analysis revealed the presence of meso-diaminopimelic acid, but no other characteristic amino acids or sugars in the murein (cell wall type III). According to polar lipid analysis, all strains showed PL II-type phospholipid composition; phosphatidylethanolamine and glycolipid were detected together with some unidentified phospholipids. The isoprenoid quinone composition of the new isolates differed slightly from that of the other two Thermobifida species described thus far. The partial 16S rDNA sequence similarity of the four strains reached 99.8-100%, whereas a nearly complete 16S rDNA sequence of TB100T, the representative strain of this collection, showed only 97.4 and 97.8% similarity to the corresponding rDNA sequences of the type strains of Thermobifida fusca and Thermobifida alba, respectively. These four isolates constituted a homogeneous group with levels of DNA-DNA homology ranging from 94.6 to 99.1%. The DNA-DNA relative homology values of strain TB100T to Thermobifida fusca ATCC 27730T and Thermobifida alba DSM 43795T were 48.1 and 57%, respectively. On the basis of phenotypic, chemotaxonomic and genotypic data, the strains are assigned to a new species within the genus Thermobifida under the name Thermobifida cellulolytica sp. nov. The type strain is TB100T (= DSM 44535T = NCAIM B01997T).

Short-term hypobaric hypoxia enhances visual contrast sensitivity

The effect of hypoxia on early visual functions remains a controversial area of research. To explore this question, we measured static and dynamic visual contrast sensitivity in 14 healthy volunteers at a simulated altitude of 5500 m. In comparison with the baseline condition (mean arterial oxygen saturation: 98.4%), contrast sensitivity significantly increased after 5, 10 and 15 min of hypoxic exposure (saturation: 82.9%, 77.0%, 74.3%, respectively). After 10 min, this enhancement was markedly pronounced under dynamic conditions. Returning to the baseline altitude (saturation: 97.7%), contrast sensitivity recovered, mostly at the lower spatial frequencies. There was a significant negative relationship between arterial oxygen saturation and contrast sensitivity values at low and medium spatial frequencies (0.5-4.8 c/deg). These results suggest that early visual processing may be enhanced during short-term hypoxic challenge.

Fly-attracting volatiles produced by Rhodococcus fascians and Mycobacterium aurum isolated from myiatic lesions of sheep

Bacterial strains isolated from the healthy breech mucosa and myiatic wounds of ewes were tested for their volatile production as fly attractants towards Wohlfahrtia magnifica (Diptera: Sarcophagidae). Cultures were studied as fly baits in field experiments, and strains performing with the best chemotropic effect were selected for further analysis. Static and dynamic headspace samples from shaken cultures were examined by gas chromatography-mass spectrometry (GC-MS). Strains identified as Rhodococcus fascians and Mycobacterium aurum produced various volatile sulfur compounds and benzene, and proved to be the best fly attractants.