Expanding the clinical spectrum of the 'HDAC8-phenotype' - implications for molecular diagnostics, counseling and risk prediction.

Cornelia de Lange syndrome (CdLS) is a clinically heterogeneous disorder characterized by typical facial dysmorphism, cognitive impairment and multiple congenital anomalies. Approximately 75% of patients carry a variant in one of the five cohesin-related genes NIPBL, SMC1A, SMC3, RAD21 and HDAC8. Herein we report on the clinical and molecular characterization of 11 patients carrying 10 distinct variants in HDAC8. Given the high number of variants identified so far, we advise sequencing of HDAC8 as an indispensable part of the routine molecular diagnostic for patients with CdLS or CdLS-overlapping features. The phenotype of our patients is very broad, whereas males tend to be more severely affected than females, who instead often present with less canonical CdLS features. The extensive clinical variability observed in the heterozygous females might be at least partially associated with a completely skewed X-inactivation, observed in seven out of eight female patients. Our cohort also includes two affected siblings whose unaffected mother was found to be mosaic for the causative mutation inherited to both affected children. This further supports the urgent need for an integration of highly sensitive sequencing technology to allow an appropriate molecular diagnostic, genetic counseling and risk prediction.

Effect of endurance training on seizure susceptibility, behavioral changes and neuronal damage after kainate-induced status epilepticus in spontaneously hypertensive rats.

The therapeutic efficacy of regular physical exercises in an animal model of epilepsy and depression comorbidity has been confirmed previously. In the present study, we examined the effects of endurance training on susceptibility to kainate (KA)-induced status epilepticus (SE), behavioral changes and neuronal damage in spontaneously hypertensive rats (SHRs). Male SHRs were randomly divided into two groups. One group was exercised on a treadmill with submaximal loading for four weeks and the other group was sedentary. Immediately after the training period, SE was evoked in half of the sedentary and trained rats by KA, while the other half of the two groups received saline. Basal systolic (SP), diastolic (DP) and mean arterial pressure (MAP) of all rats were measured at the beginning and at the end of the training period. Anxiety, memory and depression-like behaviour were evaluated a month after SE. The release of 5-HT in the hippocampus was measured using a liquid scintillation method and neuronal damage was analyzed by hematoxylin and eosin staining. SP and MAP of exercised SHRs decreased in comparison with the initial values. The increased resistance of SHRs to KA-induced SE was accompanied by an elongated latent seizure-free period, improved object recognition memory and antidepressant effect after the training program. While the anticonvulsant and positive behavioral effects of endurance training were accompanied by an increase of 5-HT release in the hippocampus, it did not exert neuroprotective activity. Our results indicate that prior exercise is an effective means to attenuate KA-induced seizures and comorbid behavioral changes in a model of hypertension and epilepsy suggesting a potential influence of hippocampal 5-HT on a comorbid depression. However, this beneficial impact does not prevent the development of epilepsy and concomitant brain damage.

PSMA PET/CT with Glu-urea-Lys-(Ahx)-[68Ga(HBED-CC)] versus 3D CT volumetric lymph node assessment in recurrent prostate cancer.

PURPOSE: PET/CT with the PSMA ligand is a powerful new method for the early detection of nodal metastases in patients with biochemical relapse. The purpose of this retrospective investigation was to evaluate the volume and dimensions of nodes identified by Glu-urea-Lys-(Ahx)-[(68)Ga(HBED-CC)] ((68)Ga-PSMA-11) in the setting of recurrent prostate cancer. METHODS: All PET/CT images were acquired 60 ± 10 min after intravenous injection of (68)Ga-PSMA-11 (mean dose 176 MBq). In 21 patients with recurrent prostate cancer and rising PSA, 49 PSMA-positive lymph nodes were identified. Using semiautomated lymph node segmentation software, node volume and short-axis and long-axis dimensions were measured and compared with the maximum standardized uptake values (SUVmax). Round nodes greater than or equal to 8 mm were considered positive by morphological criteria alone. The percentage of nodes identified by elevated SUVmax but not by conventional morphological criteria was determined. RESULTS: The mean volume of (68)Ga-PSMA-11-positive nodes was 0.5 ml (range 0.2 - 2.3 ml), and the mean short-axis diameter was 5.8 mm (range 2.4 - 13.3 mm). In 7 patients (33.3 %) with 31 PSMA-positive nodes only 11 (36 %) were morphologically positive based on diameters >8 mm on CT. In the remaining 14 patients (66.7 %), 18 (37 %) of PSMA positive lymph nodes had short-axis diameters <8 mm with a mean short-axis diameter of 5.0 mm (range 2.4 - 7.9 mm). Thus, in this population, (68)Ga-PSMA-11 PET/CT detected nodal recurrence in two-thirds of patients who would have been missed using conventional morphological criteria. CONCLUSION: (68)Ga-PSMA-11 PET/CT is more sensitive than CT based 3D volumetric lymph node evaluation in determining the node status of patients with recurrent prostate cancer, and is a promising method of restaging prostate cancers in this setting.

SUV of [68Ga]DOTATOC-PET/CT Predicts Response Probability of PRRT in Neuroendocrine Tumors.

PURPOSE: The goal of our study was to quantify the expression of the somatostatin receptors (SSTR2) using the maximum standardized uptake value (SUVmax) of [(68)Ga]DOTA(0)-Phe(1)-Tyr(3)-octreotide (DOTATOC) positron emission tomography (PET)-computed tomography (CT) in liver metastases of patients with neuroendocrine tumors (NETs) prior to peptide receptor radiation therapy (PRRT) and compare the initial tumor uptake with the final treatment outcome. PROCEDURES: SSTR2 expression of the 60 liver metastases in 30 NET patients was assessed at baseline and after PRRT by measuring SUVmax, tumor to spleen ratio (T/S ratio), and tumor to liver ratio (T/L ratio). Based on morphological changes and tumor size measured at baseline and follow-up contrast-enhanced CT (after three cycles of PRRT), lesions were divided into two groups by the following: (i) responding (n = 40) and (ii) non-responding (n = 20). RESULTS: Statistically significant differences were observed in the mean SUVmax for non-responding vs. responding lesions at baseline (18.00 ± 3.59 vs. 33.55 ± 4.62, p < 0.05) and for the mean T/S ratio (1.20 ± 0.37 vs. 1.90 ± 0.45, p < 0.05) and the mean T/L ratio (3.15 ± 0.53 vs. 4.97 ± 0.62, p < 0.05). Using the receiver operating characteristic curves, SUVmax was found a better metric than both T/L ratio and T/S ratio (area under the curve (AUC) of SUVmax 0.87; T/L ratio 0.78; T/S ratio 0.73) as a stratification criterion. Using a threshold value of >16.4 for SUVmax, the sensitivity and specificity in predicting responding lesions were 95 and 60 %, respectively. CONCLUSION: We propose a SUVmax cutoff of >16.4 from [(68)Ga]DOTATOC-PET-CT to select patients for PRRT. A T/L ratio >2.2 might present a scanner-independent criterion that enables the translation of our results to other institutions. However, the robustness of this arbitrary unit still needs to be evaluated with different PET scanners.

[The current view of the diagnosis and management of amebiasis in the light of the authors own case reports]. / Soucasný pohled na diagnostiku a lécbu amébózy ve svetle vlastní kazuistické zkusenosti.

This comprehensive review is focused on a serious protozoan disease, amebiasis. This disease is caused by the human parasite Entamoeba histolytica (E. histolytica), the second leading cause of mortality due to protozoan disease worldwide (the leading cause is malaria). The incidence of amebiasis in the Czech Republic is very low, but it may be underreported as the disease often escapes diagnosis. Intestinal colonisation by E. histolytica may be asymptomatic. The clinical picture ranges from diarrhea to colitis or fulminant colitis when the parasite progresses to the trophozoite stage. Secondary dissemination in the blood or lymph system may induce systemic signs of the disease. Liver abscess is the most common extraintestinal form of amebiasis. The diagnosis of intestinal amebiasis is based on the clinical picture and parasitological examination of the stool. To diagnose extraintestinal amebiasis, serology tests are used to detect antibodies in the blood. Recently, molecular methods have been increasingly used for the detection of the nucleic acids of the pathogen in biological specimens. The first line therapy for amebiasis are 5-nitroimidazole drugs, currently available in the Czech Republic. However, surgical intervention should also be considered in patients with a severe course of the disease. Included in the review are the case reports of patients with severe concomitant intestinal and extraintestinal amebiasis.

Adaptive changes in photosynthetic performance and secondary metabolites during white dead nettle micropropagation.

The white dead nettle, Lamium album L., is an herb that has been successfully cultivated under in vitro conditions. The L. album micropropagation system offers a combination of factors (light intensity, temperature, carbon dioxide (CO2) level, humidity) that are limiting for plant growth and bioactive capacity. To get a better understanding of the mechanism of plant acclimation towards environmental changes, we performed a comparative investigation on primary and secondary metabolism in fully expanded L. album leaves during the consecutive growth in in situ, in vitro, and ex vitro conditions. Although the genetic identity was not affected, structural and physiological deviations were observed, and the level of bioactive compounds was modified. During in vitro cultivation, the L. album leaves became thinner with unaffected overall leaf organization, but with a reduced number of palisade mesophyll layers. Structural deviation of the thylakoid membrane system was detected. In addition, the photosystem 2 (PS2) electron transport was retarded, and the plants were more vulnerable to light damage as indicated by the decreased photoprotection ability estimated by fluorescence parameters. The related CO2 assimilation and transpiration rates were subsequently reduced, as were the content of essential oils and phenolics. Transfer of the plants ex vitro did not increase the number of palisade numbers, but the chloroplast structure and PS2 functionality were recovered. Strikingly, the rates of CO2 assimilation and transpiration were increased compared to in situ control plants. While the phenolics content reached normal levels during ex vitro growth, the essential oils remained low. Overall, our study broadens the understanding about the nature of plant responses towards environmental conditions.

Impact of peptide receptor radionuclide therapy on the 68Ga-DOTATOC-PET/CT uptake in normal tissue.

AIM: Positron-emission tomography/computed tomography (PET/CT) with [68Ga]DOTA0-Phe1-Tyr3-octreotide (68Ga-DOTA-TOC) became a standard for somatostatin receptor imaging. We investigated the potential changes of normal tissue uptake in patients with neuroendocrine tumor undergoing peptide receptor radionuclide therapy (PRRT). METHODS: Sixteen patients underwent [68Ga]-DOTA-TOC-PET/CT prior and after 4-6 cycles of PRRT (mean administered activity: 13.8 GBq 90Y+ 9.6 177Lu). The maximum standardized uptake values (SUVmax) of pituitary, thyroid, spleen, liver parenchyma, pancreas, kidneys and adrenals were determined, respectively. RESULTS: SUVmax values prior and after PRRT were in pituitary (5, 56±2,91/ 4,47±2,53), thyroid (2.05±1.11/ 2.49±2.47), spleen (24.95±14.20/20.06±8.53), liver (7.13±3.96/6.62±2.63), pancreas (6.96±1.99/6.83±2.00), kidneys (13.0±3.85/11.31±3.31) and adrenals (9.65± 4.20/7.10±2.86). A comparison of pre- and post treatment values revealed no significant differences (P>0.05) in any of these organs. CONCLUSION: The uptake of [68Ga] DOTA-TOC in normal tissue is not significantly affected by PRRT. This is relevant with regards to therapeutic monitoring were tumor-to-non-tumor ratio seems to be the most robust biomarker.

[A detailed study of colon polyps]. / Podrobná studie o polypech tlustého streva.

UNLABELLED: INTRODUCTION, STUDY AIM: Colorectal carcinoma is one of the most frequent malignancies. Most frequently, neoplasms, including malignant precursors, are in the form of polyps, although these might be of a non-tumour origin. The aim of this prospective multicentre study was to provide an overview of coloscopic identification and biological nature of polyps. RESULTS: 3,400 consecutive coloscopies performed between 2009 and 2010 were analyzed. At different centres, the top of the cecum was reached in 89% to 93% and terminal ileum in 73% to 87% of cases. In the above 40 age group, 26.6% were screening coloscopies. The mean age of the above 40 patients was 56 years. The incidence of potential neoplastic lesions (polyps, carcinomas), advanced adenomas and carcinomas were: 7.8 %, 0.8 % and 0.16 %, respectively, in the above 40 age group, 41.5 %, 9.8 % and 1.6 %, respectively, in the 40-50 years age group and 70.5 %, 31.3 % and 6.8 %, respectively, in the above 50 age group. The incidence of tubular adenoma and hyperplastic polyps was 23.9% and 66.2%, respectively, in the below 40 age group and 53.1% and 26.1% in the above 50 age group. 57.8% of advances neoplasms were located in the rectosigmoid a descendent colon. The incidence ratio for adenomas and hyperplastic polyps was 76.6% and 14%, respectively, for rectosigmoid colon, 63.6 and 17.4 %, respectively, for descendent colon, 63.6 and 11.4 % for traverse colon and 63,4 a 17,9 %, respectively, for cecum and ascendant colon. The incidence of tubulovillous adenomas and hyperplastic polyps in pedunculated polyps larger than 1 cm was 19.4 % and 20.4 %, respectively, and 34.2 % and 13.1 %, respectively, in other polyps. The incidence of potential lesions (polyps and carcinomas), advanced adenomas, carcinomas and advanced neoplasms was 66.7 %, 23.1 %, 5.8 % and 28.9 %, respectively, in women and 63.1 %, 30.0 %, 5.7 % and 34.7 %, respectively, in men. CONCLUSION: The top of the cecum was reached in a higher proportion of cases than required, although this was lower than in the majority of other recent studies. Terminal ileum was reached in high number of cases. The incidence of polyps and neoplasms rose sharply from 40 years of age. Therefore, the screening threshold should be extended to the below 50 age group. Hyperplastic polyps predominated in younger age and adenomas in the above 40 age group. Histological profile was similar and did not suggest importantly different pathogenesis with respect to localization. There were relatively fewer adenomas and more hyperplastic polyps in pedunculated polyps and vice verse in other types of polyps, suggesting a higher risk associated with non-pedunculated lesions. Both sexes differed less than suggested based on epidemiological statistics.

A novel SOX9 nonsense mutation, q401x, in a case of campomelic dysplasia with XY sex reversal.

Campomelic dysplasia (CD, MIM 114290) is a rare, often lethal, dominantly inherited, congenital skeletal dysplasia, associated with male-to-female autosomal sex reversal and due to de novo mutations of the SOX9 gene, a tissue-specific transcription factor gene involved both in skeletogenesis and male sexual differentiation. Here we report on a 4 months-old 46,XY sex reversed infant with typical clinical features for CD due to a novel mutation of the SOX9 gene, Q401X, leading to synthesis of a truncated SOX9 protein that completely lacks the C-terminal transactivation domain.

Dermatophytes in Republic of Macedonia.

A total of 1742 clinically suspected samples was examined for the incidence and distribution of dermatophytes in the Republic of Macedonia from June 2007 to Jan. 2009. 600 dermatophytes were isolated and identified. In the studied period 9 different dermatophyte species were isolated, namely Trichophyton rubrum (48.83%), Microsporum canis (20%), Trichophyton mentagrophytes var. interdigitale (16.83%), Epidermophyton floccosum (4.17%), Trichophyton verrucosum (3.83%), Trichophyton mentagrophytes var. mentagrophytes (3%), Trichophyton violaceum (1.67%), Microsporum ferrugineum (1%) and Microsporum gypseum (0.67%). The anthropophilic dermatophytic species are predominant. Tinea unguium (onychomycosis) (37.50%) is the most frequently diagnosed dermatophytosis followed by tinea pedis (19.17%), tinea corporis (15.33) and tinea capitis (15.17%). Furthermore there is an increased number of Microsporum canis isolates in tinea capitis patients. Microsporum canis infection of the scalp remains a serious epidemiological problem in R. Macedonia.

FOXL2 copy number changes in the molecular pathogenesis of BPES: unique cohort of 17 deletions.

Blepharophimosis Syndrome (BPES) is an autosomal dominant developmental disorder of the eyelids with or without ovarian dysfunction caused by FOXL2 mutations. Overall, FOXL2deletions represent 12% of all genetic defects in BPES. Here, we have identified and characterized 16 new and one known FOXL2 deletion combining multiplex ligation-dependent probe amplification (MLPA), custom-made quantitative PCR (qPCR) and/or microarray-based copy number screening. The deletion breakpoints could be localized for 13 out of 17 deletions. The deletion size is highly variable (29.8 kb - 11.5 Mb), indicating absence of a recombination hotspot. Although the heterogeneity of their size and breakpoints is not reflected in the uniform BPES phenotype, there is considerable phenotypic variability regarding associated clinical findings including psychomotor retardation (8/17), microcephaly (6/17), and subtle skeletal features (2/17). In addition, in all females in whom ovarian function could be assessed, FOXL2 deletions proved to be associated with variable degrees of ovarian dysfunction. In conclusion, we present the largest series of BPES patients with FOXL2 deletions and standardized phenotyping reported so far. Our genotype-phenotype data can be useful for providing a prognosis (i.e. occurrence of associated features) in newborns with BPES carrying a FOXL2 deletion.

A pharmacoeconomical model for choice of a treatment for pregnant women with gestational diabetes.

This study discusses two main questions: the direct medical costs and the clinical effectiveness of the hospital treatment with insulin of pregnant women with gestational diabetes (GD). A prospective study that includes 50 women with GD is performed. The pregnant women are divided into 2 groups: Group I (n=30) - pregnant women treated only with a diet; and Group II (n=20) - pregnant women treated with diet and insulin. We found that the metabolite compensation degree is improved after the applied treatment with insulin. The coefficient cost/effectiveness is 6954 lv./100 women. The analysis decision tree confirms in a very convenient way the fact that insulin treatment is a clinically more effective and financially more profitable strategy.

Philadelphia variant, t(5;9;22)(q13;q34;q11), in a case with chronic myeloid leukemia.

In this paper we report on a case of chronic myeloid leukemia (CML) with a Philadelphia variant involving chromosome 5 as a second change of the standard Philadelphia chromosome (Ph). Molecular analysis found a fusion gene BCR-ABL with participation of exons b3 and a2, respectively (b3a2). The molecular variant of the fusion gene BCR/ ABL or the rare involvement of chromosome 5 could possibly explain the mild course of the disease.

Chromosomal gains and losses are uncommon in hairy cell leukemia: a study based on comparative genomic hybridization and interphase fluorescence in situ hybridization.

In contrast to other subtypes of lymphoproliferative malignancies, the genetic mechanisms underlying the pathogenesis of hairy cell leukemia (HCL) are unknown. We studied densely infiltrated splenic tissue of 14 cases of HCL for the presence of chromosomal gains and losses by comparative genomic hybridization (CGH). Chromosomal imbalances were detected in only four of the 14 cases. Chromosomal gains involved the regions 5q13-q31 (two cases) and 1p32-p36.2 (one case). A loss of the region 11q14-q22 was found in one additional patient. The imbalances affecting the regions 5q and 11q were confirmed by interphase fluorescence in situ hybridization (FISH) using PAC clone 144G9 (5q31) and YAC clones 755B11 (11q22.3-q23.1) and 801E11 (11q22.3-q23.1 spanning the ATM gene) and occurred in 61% to 75% of analyzed nuclei. The latter DNA probes and probes hybridizing to chromosomal regions, which are frequently deleted in other subtypes of non-Hodgkin lymphomas (NHL), namely 9p21/ P16(INK4A), 13q14/D13S25, and 17p13/P53 were subsequently applied to all 14 cases of HCL, but no additional abnormalities were found. We conclude that overrepresentation of chromosome 5 represents a recurrent aberration in HCL and that the commonly overrepresented region resides in 5q13-q31. Chromosomal imbalances including deletions of the tumor suppressor gene loci 9p21/P16(INK4A), 13q14/D13S25, and 17p13/P53 rarely occur in HCL in contrast to some other subtypes of B-cell NHL. The pathogenetic role of 11q/ATM alterations in HCL remains to be determined.

Fluorescent coupled enzyme assays for D-alanine: application to penicillin-binding protein and vancomycin activity assays.

D-Alanine (D-Ala) is a ubiquitous constituent of bacterial cell walls. Assays for D-Ala can be used to investigate several aspects of cell wall biosynthesis and the effects of antibiotics on this process. High-sensitivity fluorescent assays for D-Ala were developed in a microtiter plate format based on d-aminoacid oxidase/horseradish peroxidase (DAO/HRP)-coupled reactions. For comparative purposes the classic chromogenic (UV-vis) assay using o-phenylenediamine (OPD) was also adapted to microtiter plates. OPD gave a lower limit of sensitivity of 2 nmol and was linear up to 60 nmol. Two commercially available fluorogenic HRP substrates were then tested in this assay. Amplex Red (AR) gave a lower limit of sensitivity of 2 pmol and was linear up to 400 pmol d-Ala. QuantaBlu (QB) based assays exhibited a lag in their response to D-Ala corresponding to 50 pmol D-Ala. This lag complicated calibration, but could be eliminated by addition of 150 pmol D-Ala to all assays. The QB assays were linear up to 3000 pmol D-Ala and gave a lower limit of sensitivity of 10 pmol. These assays are demonstrated for the characterization of the dd-carboxypeptidase activity of a soluble form of Escherichia coli penicillin-binding protein 5 (PBP 5) against the classic PBP substrate diacetyl-L-Lys-D-Ala-D-Ala. AR and QB based assays gave identical v/E(T) profiles, whereas OPD based assays gave slightly (10%) higher activity. This is consistent with the loss of a small amount of E. coli PBP 5 activity during the dilution necessary prior to its use in the highly sensitive fluorescent assays. These assays were then demonstrated for characterization of vancomycin binding to a D-Ala-D-Ala-based substrate.

Analysis of the P53, RB/D13S25, and P16 tumor suppressor genes in marginal zone B-cell lymphoma: An interphase fluorescence in situ hybridization study.

The genetic mechanisms underlying the genesis, disease progression, and high-grade transformation of marginal zone B-cell lymphoma (MZBCL) are poorly understood. We analyzed 33 cases of histologically and immunophenotypically well-characterized MZBCL (12 extranodal, 11 nodal, and 10 splenic MZBCL; 27 at primary diagnosis and six during the course of disease) by dual-color interphase fluorescence in situ hybridization (FISH) for deletions of tumor suppressor genes. We investigated loci known to play a role in the genesis or disease progression of other subtypes of lymphoid malignancies, namely the P53 gene (17p13), the retinoblastoma gene (RB, 13q14), the D13S25 locus (13q14), and the P16(INK4A) gene (9p21). Heterozygous deletions of P53 were detected in three out of the 33 cases, including two splenic and one extranodal MZBCL. One of these patients was analyzed at primary diagnosis and two during the course of disease. Heterozygous deletions of the RB gene (nodal MZBCL) and D13S25 (splenic MZBCL) were found in one case each. P16 deletions were not detected in any of our cases. We conclude that deletions of the analyzed tumor suppressor genes are relatively rare in MZBCL, which contrasts with the findings in some other subtypes of NHL.

Polysomy 13 with concomitant deletion of 13q13-14 involving the retinoblastoma gene and the D13S25 locus in a case of acute myeloid leukemia.

We herein describe a case of acute myeloblastic leukemia (AML), FAB subtype M4, with an unfavorable clinical course and a complex karyotype, including 4-9 copies of chromosome 13. Polysomy 13 was a result of clonal evolution. Fluorescence in situ hybridization (FISH) revealed a cytogenetically unrecognizable deletion within 13q13-14 that included the retinoblastoma gene (RB) and the D13S25 locus in all but one copy of chromosome 13. The only chromosome 13 that did not show a deletion affecting the q13-14 region was translocated to chromosome 7, resulting in a dic(7;13)(q21;p11). In this case, the coexistence of polysomy and a partial deletion within the same chromosome point toward a possible formation of a fusion product with oncogenic potential and its consecutive amplification as a critical alteration in this case.

The discrimination of abrupt changes in speed and direction of visual motion.

A random dot pattern that moved within an invisible aperture was used to present two motions contiguously in time. The motions differed slightly either in speed (Experiments 1 and 3) or in direction (Experiments 2 and 4) and the subject had to discriminate the sign of the change (e.g. increment or decrement). The same discrimination task was performed when the two motions were temporally separated by 1 s. In Experiments 1 and 2 discrimination thresholds were measured with motion durations of 0.125, 0.25, 0.5 and 1.0 s and mean speeds of 2, 4, 8, and 16 degrees/s. In Experiments 3 and 4 thresholds were measured with aperture widths of 5 and 20 cm. The discrimination of contiguous motions progressively deteriorated with decreasing duration and mean speed of motion. For the lowest value of duration the Weber fraction for contiguous speeds was more than three times as the Weber fractions for separate speeds. For the same low value of duration the thresholds for discrimination of direction of contiguous motions were only about 50% higher than the thresholds for separate motions. The Weber fraction for contiguous speeds was ca. three times higher with the smaller aperture than with the larger one, provided the ratio 'aperture width mean speed' (i.e. the lifetime of the moving dots) was less than 0.3 s. Aperture width did not affect the discrimination of direction of contiguous motions. The discrimination of contiguous motions is discussed together with the known data for detection of changes in speed and direction. It is suggested that both, detection of changes in speed and discrimination of the sign of speed changes, may be performed by a common visual mechanism.

Genetic abnormalities in marginal zone B-cell lymphoma.

Marginal zone B-cell lymphoma (MZBCL) including extranodal mucosa-associated lymphoid tissue (MALT)-type lymphoma, nodal, and splenic MZBCL represents a distinct subtype of B-non-Hodgkin's lymphoma. Recently, important progress in the elucidation of the genetic mechanisms underlying the pathogenesis and disease progression of these lymphomas has been made. The API2 gene, an inhibitor of apoptosis, and the novel MLT gene have been found to be altered by the t(11;18)(q21;21), which represents the most frequent structural chromosomal abnormality in extranodal low-grade MALT lymphoma. Another gene involved in the regulation of apoptosis, the BCL10 gene, has been cloned from a MALT lymphoma cytogenetically characterized by the t(1;14)(p22;q32). Along the same lines, inactivating mutations of the proapoptotic FAS gene have been detected in a relatively high proportion of extranodal MZBCLs. Considering these data and the fact that at least some MALT lymphomas show low levels of apoptosis and seem to escape from FAS-mediated apoptosis one may speculate that abrogation of apoptosis constitutes a central pathogenetic mechanism in the development of these lymphomas. The pathogenetic role of trisomy 3, the most frequent numerical chromosomal change of MZBCL, is not known. The minimal overrepresented region has been delineated to 3q21-23 and 3q25-29 using comparative genomic hybridization. The BCL6 proto-oncogene, located on 3q27, which is rearranged in some MZBCL and a high proportion of large cell B-cell lymphomas with extranodal localization, represents one of the candidate genes residing in these critical regions.

Novel Philadelphia variant t(Y;9;22)(q12;q34;q11) in a case of chronic myeloid leukemia.

A novel Philadelphia (Ph) variant translocation, t(Y;9;22)(q12;q34;q11), was detected in a 63-year-old man with a newly diagnosed chronic myeloid leukemia (CML). Reverse transcription polymerase chain reaction (RT-PCR) analysis revealed a b3a2 fusion transcript. Fluorescence in situ hybridization (FISH) utilizing library probes, subtelomeric cosmid probes, and probes hybridizing to the ABL and BCR genes showed a reciprocal three-way translocation involving Yq12, 9q34, and 22q11, and a BCR-ABL fusion signal on der(22). The subtelomeric Yq probe hybridizing centromerically to the IL9 receptor gene and covering the centromeric portion of the SYBL1 gene was found to be translocated to der(9).