211 IN VITRO CULTURE CONDITIONS AFFECT GENE EXPRESSION PATTERN OF BOVINE BLASTOCYST IN A STAGE-SPECIFIC MANNER

The aim of this study was to examine the effect of in vitro culture conditions at specific phases of early embryonic development on the transcriptome profile of bovine blastocysts. Simmental heifers were superovulated and artificially inseminated 2 times with the same frozen–thawed commercial bull semen. Using nonsurgical endoscopic oviductal flushing technology (Besenfelder et al. 2001 Theriogenology 55, 837–845), 6 different blastocyst groups were flushed out at different time points (2-, 4-, 8-, 16-, 32-cell and morula). After flushing, embryos cultured under in vitro conditions until the blastocyst stage. Blastocysts from each group were collected and pooled in groups of 10. Complete in vivo blastocysts were produced and used as control. A unique custom microarray (Agilent) containing 42 242 oligo probes (60-mers) was used over 6 replicates of each group v. the in vivo control group to examine the transcriptome profile of blastocysts. A clear difference in terms of the number of differentially expressed genes (DEG, fold change ≥2, false discovery rate ≤0.05) has been found between groups flushed out at 2-, 4-, and 8-cell (1714, 1918, 1292 DEG, respectively) and those flushed out at 16-, 32-cell and morula stages and cultured in vitro until blastocyst stage (311, 437, 773 DEG, respectively) compared with the complete vivo group. Ontological classification of DEG showed cell death to be the most significant function in all groups. However, the longer time embryos spent under in vitro conditions, the more the percentage of DEG involved in cell death and apoptosis processes are represented in those groups. In addition, genes related to post-translational modification and gene expression processes were significantly dysregulated in all groups. Pathway analysis revealed that protein ubiquitination pathway was the dominant pathway in the groups flushed out at 2-, 4-, and 8-cells but not in the other groups flushed at later stages compared with the in vivo control group. Moreover, retinoic acid receptor activation and apoptosis signalling pathways followed the same pattern. Embryos flushed out before the time of embryonic genome activation and subsequently cultured in vitro were highly affected by culture conditions. Overall, the results of the present study showed that despite the fact that embryos originated from the same source, in vitro culture condition affected embryo quality, measured in terms of gene expression, in a stage-specific manner.

Endometrial response of beef heifers on day 7 following insemination to supraphysiological concentrations of progesterone associated with superovulation

Ovarian stimulation is a routine procedure in assisted reproduction to stimulate the growth of multiple follicles in naturally single-ovulating species including cattle and humans. The aim of this study was to analyze the changes induced in the endometrial transcriptome associated with superovulation in cattle and place these observations in the context of our previous data on changes in the endometrial transcriptome associated with elevated progesterone (P4) concentrations within the physiological range and those changes induced in the embryo due to superovulation. Mean serum P4 concentrations were significantly higher from day 4 to day 7 in superovulated compared with unstimulated control heifers (P < 0.05). Between-group analysis revealed a clear separation in the overall transcriptional profile of endometria from unstimulated control heifers (n = 5) compared with superovulated heifers (n = 5). This was reflected in the number of differentially expressed genes (DEGs) identified between the two groups with 795 up- and 440 downregulated in superovulated endometria. Ten times more genes were altered by superovulation (n = 1,234) compared with the number altered due to elevated P4 within physiological ranges by insertion of a P4-releasing intravaginal device (n = 124) with only 22 DEGs common to both models of P4 manipulation. Fewer genes were affected by superovulation in the embryo compared with the endometrium, (443 vs. 1,234 DEGs, respectively), and the manner in which genes were altered was different with 64.5% of genes up- and 35.5% of genes downregulated in the endometrium, compared with the 98.9% of DEGs upregulated in the embryo. In conclusion, superovulation induces significant changes in the transcriptome of the endometrium which are distinct from those in the embryo.

Transcriptome profile of early mammalian embryos in response to culture environment

Early embryonic development, the period from maturation until blastocyst formation, is one of the most critical periods of mammalian development involves various morphological, cellular, and biochemical changes related to genomic activity. During the post-fertilization period, several major developmental events occur in the embryo which are regulating by a harmonized expression of genes and strongly influenced by culture conditions. The products of these genes are involved in various biological processes including metabolism, growth factor/cytokine signaling, stress adaptation, transcription and translation, epigenetic regulation of transcription, apoptosis, compaction and blastocyst formation. Post-fertilization culture environment is known to be the most important factor determining the quality of the resulting embryos as indicated in terms of cryo-tolerance and relative abundance of transcripts. However, the exact effect of culture conditions on gene expression and subsequent influences on molecular pathways controlling early development is still unknown. A number of culture environmental factors can influence the gene expression of produced embryos such as media composition, serum supplementation, number of embryos present in the culture drop and gas atmosphere. During the last ten years several studies were concerned with differences in the transcriptome profile of embryos produced under different environmental conditions and its subsequent influence on embryo developmental competence. From these studies, several genes have been determined as candidate genes controlling preimplantation embryo development and affecting its quality. Here we will discuss results of different experiments investigated the effect of different culture conditions on the transcriptome profile of bovine blastocyst. These experiments identified molecular mechanisms and pathways that influenced by culture conditions and this will enable to launch strategies to modify culture conditions to enhance the development of competent blastocyst.

cDNA microarray analysis of gene expression in parthenotes and in vitro produced buffalo embryos

The retarded development of parthenote embryo could be due to aberrant epigenetic imprinting, which may disrupt many aspects and lead to conceptus demise. The present work was conducted to: 1) compare the development of in vitro produced (IVP) and parthenogenetically developed (P) buffalo embryos from the 2-cell to blastocyst stage; 2) investigate the global gene expression profile and search for new candidate transcripts differing between IVP and P buffalo blastocyst using cDNA microarray analysis (validated by Real Time PCR); 3) follow the particular expression patterns of PLAC8 and OCT4 genes at five different stages of preimplantation development by Real Time PCR; and 4) study the expression of CDX2 at the blastcocyst stage. Cleavage rate was higher (P < 0.05) in P than IVP buffalo embryos, while, progression to blastocyst and number of cells per blastocyst were lower (P < 0.05) in P than IVP blastocysts. Microarray analysis indicate that 56 differentially expressed genes between the two groups, of which 51 genes (91.07%) were up-regulated, and five genes were downregulated in IVP blastocyst, using 1.4 fold-changes as a cutoff. Differentially expressed genes are related to translation, nucleic acid synthesis, cell adhesion and placentation. Validation of candidate genes revealed that the transcript abundance of PTGS2, RPS27A, TM2D3, PPA1, AlOX15, RPLO and PLAC8 were downregulated (7/8) in parthenote blastocyst compared to the IVP blastocyst. PLAC8 gene expression was higher (P < 0.05) at 2-cell, morula and blastocyst stages in IVP embryos compared with parthenote embryos. The OCT4 gene expression was higher (P < 0.05) in 2-cell, 4-cell, 8-cell and blastocysts produced in vitro. In conclusion, the retarded development of parthenogenetic buffalo embryos could be due to downregulation of genes related to translation, nucleic acid synthesis, cell adhesion, and placental development. The low expression of PLAC8 and OCT4 during the different stages of development may be responsible, in part, to the failure of development of parthenote buffalo embryos.

134 TRANSCRIPTOME PROFILE OF BOVINE BLASTOCYSTS DERIVED FROM ALTERNATIVE IN VIVO AND IN VITRO CULTURE CONDITIONS AT SPECIFIC PHASES OF EARLY EMBRYONIC DEVELOPMENT

An understanding of gene expression patterns due to altered environmental conditions during different time points of the pre-implantation period would improve our knowledge on regulation of embryonic development and improve success of embryo culture. The aim of this study was to examine the effect of alternative in vivo and in vitro culture conditions at specific phases of early embryonic development on transcriptome profile of bovine blastocysts. Using nonsurgical endoscopic oviducal transfer technology, 5 different blastocyst groups were produced. The first 2 groups were matured in vitro and then either transferred after maturation or after in vitro fertilization to synchronized recipients. The other 3 groups were matured, fertilized and cultured in vitro until 4-cell, 16-cell and morula stage before transfer. Blastocysts from each group were collected by uterine flushing at Day 7 and pooled in groups of 10. Complete in vitro (IVP) and in vivo blastocysts were produced and used as controls. A unique custom microarray (Agilent) containing 42 242 oligo probes (60-mers) was used over 6 replicates of each group vs the in vivo control group to examine the transcriptome profile of blastocysts. Compared with the in vivo control group, clear dramatic shifts were found in the number of differentially expressed genes (DEG, fold change ≥2) at 2 different time points. The first shift occurred for blastocyst groups that were transferred after in vitro fertilization and before embryonic genome activation (EGA). The second shift occurred for blastocyst groups that were transferred after EGA, as well as for the IVP group. Ontological classification of DEG showed that the more time spent under in vitro conditions, the higher the percentage of DEG involved in cell death and apoptotic processes. Moreover, lipid metabolism was the most significant process affected in the blastocysts transferred after in vitro maturation and blastocysts transferred at 16-cell stage. Most DEG involved in this process were down-regulated. Pathway analysis revealed that signalling pathways were the dominant pathways in all groups except the group that was transferred after in vitro maturation. That group showed significant down-regulation for genes involved in retinoic acid receptors activation pathways. These results showed that fertilization and EGA were the most critical developmental stages influenced by in vitro culture conditions and subsequently affect blastocyst quality, as measured in terms of gene expression patterns. Moreover, we identified molecular mechanisms and pathways that were influenced by altered culture conditions. These findings will enable the examination of strategies for modifying in vitro culture conditions at critical stages that will allow more efficient production of developmentally competent blastocysts.

Bovine blastocysts with developmental competence to term share similar expression of developmentally important genes although derived from different culture environments

This study was conducted to investigate the gene expression profile of in vivo-derived bovine embryo biopsies based on pregnancy outcomes after transferring to recipients. For this, biopsies of 30-40% embryos were taken from grade I blastocysts (International Embryo Transfer Society Manual) and the remaining 60-70% of the intact embryos were transferred to recipients. Frozen biopsies were pooled into three distinct groups based on the pregnancy outcome after transferring the corresponding parts, namely those resulting in no pregnancy (NP), pregnancy loss (PL), and calf delivery (CD). Array analysis revealed a total of 41 and 43 genes to be differentially expressed between biopsies derived from blastocysts resulting in NP versus CD and PL versus CD respectively. Genes regulating placental development and embryo maternal interaction (PLAC8) were found to be upregulated in embryo biopsies that ended up with CD. Embryo biopsies that failed to induce pregnancy were enriched with mitochondrial transcripts (Fl405) and stress-related genes (HSPD1). Overall, gene expression profiles of blastocysts resulting in NP and CD shared similar expression profiles with respect to genes playing significant roles in preimplantation development of embryo. Finally, comparing the transcript signatures of in vivo- and in vitro-derived embryos with developmental competence to term revealed a similarity in the relative abundance of 18 genes. Therefore, we were able to present a genetic signature associated with term developmental competence independent of the environmental origin of the transferred blastocysts.

254 REGULATORY microRNA IN THE BIDIRECTIONAL COMMUNICATION OF BOVINE OOCYTES AND THE SURROUNDING CUMULUS CELLS

MicroRNA (miRNA) are small molecules (˜22 nucleotide in length) that influence the expression of hundreds of genes for numerous biological processes including development. In this study we aimed to investigate the presence and role of miRNA in the bidirectional communication of oocyte and cumulus cells. For this, triplicate pools each containing 1600 immature and mature oocytes and their corresponding cumulus cells were used for miRNA isolation using miRNeasy® Mini Kit (Qiagen, Hilden, Germany). From each oocyte and cumulus cell group, 50 ng of small RNA was used for reverse transcription using RT2 miRNA First Strand Kit (SABiosciences, Frederick, MD, USA). The resulting small RNA cDNA was used as a template to profile 88 human miRNA related to cell development and differentiation using SYBR green-based real-time PCR system. Data analysis was preformed using the comparative Ct method after normalization using endogenous control RNA (SNORD44, SNORD47, SNORD48, and U6). In addition, miR-205 and miR-210 were used for localization in pre-implantation stages of embryo using 3′digoxigenin labeled, LNA- modified in situ oligonucleotide probes (Exiqon, Vedbaek, Denmark). The result of the PCR array revealed a total of 34 and 49 miRNA to be greatly abundant in immature and mature oocyte, respectively, compared with the corresponding cumulus cells, whereas only 5 and 4 miRNA were enriched in cumulus cells compared with immature and matured oocytes, respectively. Based on expression intensity, 6 oocyte enriched (miR-205, miR-150, miR-96, miR-122, miR-146a, and miR-146b-5p) and 2 cumulus-cell enriched (miR-452 and miR-210) were selected for expression analysis in pre-implantation-stage embryos and in oocyte and cumulus cells matured with or without cumulus and oocyte factors, respectively. All oocyte-specific miRNA were found to be greatly abundant in early stages of embryo development and drop after 4-cells until the blastocyst stage, following a typical maternal transcript profile. Similar results were obtained by localization of miR-205 in pre-implantation-stage embryos, in which signals were greater until the 4-cell stage and reduced thereafter. However, miR-210 and miR-452 showed no defined profile. miR-205, miR-150, miR-122, miR-146a, miR-146b-5p, and miR-452 were found to be abundant at a greater level (P < 0.05) in oocytes matured without cumulus cells compared with those matured in the presence of cumulus cells. The expression of miR-205, miR-150, and miR-122 in cumulus cells was greater in the presence of oocyte cytoplasm during maturation, whereas 16-fold increases in relative abundance of miR-210 were observed in oocyte- optimized cumulus cells. These results evidenced that oocyte and cumulus cells have a distinct set of miRNA, which is dependent on the bidirectional communication of the oocyte and the surrounding cumulus cells. Moreover, maternal miRNA were found to persist until the major genome activation in bovine.

240 DIFFERENCES IN GLOBAL TRANSCRIPTOME PROFILE OF BOVINE BLASTOCYSTS DERIVED FROM SUPEROVULATED OR SYNCHRONIZED CYCLIC HEIFERS

Estrus synchronization and superovulation are the most widely used procedures in embryo transfer technology. However, changes in the oviduct and uterine environment due to these procedures and the subsequent influence on embryos have not yet been investigated. This study was con- ducted to investigate the effect of oviduct environment of only synchronized or superovulated cyclic heifers on the gene expression profile of blastocysts. Bovine Affymetrix array analysis was performed using 2 groups of blastocysts. The first group was bovine blastocysts produced after superovulation of Simmental heifers (n = 9) using 8 consecutive FSH injections over 4 days in decreasing doses (in total, 300-400 mg of FSH equivalent according to body weight) and flushed at Day 7 by nonsurgical endoscopic method. The second group was bovine blastocysts derived from synchronized Simmental heifers (n = 4) after transfer of 2-cell stage embryos from superovulated donor Simmental heifers (n = 9) by nonsurgical transvaginal endoscopy tubal transfer method. Total RNA was extracted from 3 pools of embryos from each experimental group (6 embryos per pool). A total of 6 biotin-labeled cRNA samples were hybridized on 6 bovine Affymetrix arrays. Data analysis was performed using LIMMA written on R package, which maintained the Bioconductor. Array data analysis revealed a total of 454 transcripts to be differen- tially expressed (P < 0.05, fold change >2) between the 2 groups. Of these, 429 and 25 were up- and down-regulated, respectively, in blastocysts derived from superovulated heifers compared with those derived from synchronized animals. Genes involved in response to stress (HSPA14 and HSPE1), cellular and metabolic processes (CPSF3, ATPIF1, POMP, and MDH2), translation (RPS17, EEF1B2, and EIF4E), and cell commu- nication (FN1, KRT18, and DSG2) were found to be enriched in blastocysts derived from superovulated animals. On the other hand, protein metabolic processes related genes (CLGN) were found to be enriched in blastocysts derived from the synchronized group. The KEGG analysis of the differentially expressed genes showed that the ribosome and oxidative phosphorylation pathways are the dominant pathways and genes involved in these pathways are greatly abundant in the blastocysts derived from superovulated animals. Quantitative real-time PCR has confirmed the transcript abundance of 7 out of 8 genes selected for validation. In conclusion, blastocysts cultured in synchronized animals post 2-cell stage showed significant differences in transcriptome profile compared with their counterparts that remained in superovulated heifers until Day 7. Further functional analysis of some selected candidate genes could give new insights into mechanisms regulating the ability of embryos to survive after transfer.

The kinase-inhibitory domain of p21-activated kinase 1 (PAK1) inhibits cell cycle progression independent of PAK1 kinase activity

p21-activated kinase 1 (PAK1) is a mediator of downstream signaling from the small GTPases Rac and Cdc42. In its inactive state, PAK1 forms a homodimer where two kinases inhibit each other in trans. The kinase inhibitory domain (KID) of one molecule of PAK1 binds to the kinase domain of its counterpart and keeps it inactive. Therefore, the isolated KID of PAK1 has been widely used to specifically inhibit and study PAK function. Here, we show that the isolated KID induced a cell cycle arrest with accumulation of cells in the G1 phase of the cell cycle with an inhibition of cyclin D1 and D2 expression. This cell cycle arrest required the intact KID and was also induced by a mutated KID unable to block PAK1 kinase activity. Furthermore, the KID-induced cell cycle arrest could not be rescued by the expression of a constitutively active PAK1-T423E mutant, concluding that this arrest occurs independently of PAK1 kinase activity. Our results suggest that PAK1 through its KID inhibits cyclin D expression and thereby enforces a cell cycle arrest. Our results also call for serious precaution in the use of KID to study PAK function.

Relationship between hepatitis C virus infection and schistosomal liver disease: not simply an additive effect

BACKGROUND

To study the association, clinical significance, and impact of hepatitis C virus (HCV) co-infection in patients with schistosomal liver disease (SLD).

METHODS

A total of 240 patients with chronic liver diseases encountered consecutively were enrolled in the study. Fifty volunteer blood donors were enrolled as controls. HCV antibody determination (enzyme-linked immunosorbent assay), qualitative and quantitative HCV RNA assay (reverse transcriptase polymerase chain reaction), and HCV genotyping (line probe assay) were performed.

RESULTS

Twenty-eight patients had SLD alone, 60 had both SLD and chronic hepatitis C (CH-C), 120 had CH-C alone, and 32 had other liver diseases. The positivity rates for HCV antibody (76% vs 20%; P < 0.001) and HCV RNA (59% vs 10%; P < 0.001) were significantly higher in the patients with SLD (n = 88) than in the volunteer blood donors (n = 50). Complications of liver cirrhosis were more common in patients with concomitant SLD and CH-C than in those with either SLD or CH-C alone. The mean levels of alanine aminotransferase (77 +/- 42 vs 93 +/- 55 IU/l; P = 0.049) and HCV RNA concentrations (3.5 +/- 1.0 vs 4.2 +/- 1.0 log copy/ml; P < 0.001) were significantly lower in patients with concomitant SLD and CH-C than in those with CH-C alone. HCV genotype 4 predominated in both these groups (93% and 98%).

CONCLUSIONS

SLD in Egypt is significantly associated with HCV infection, with the predominance of genotype 4. Concurrent HCV infection and SLD result in much more severe liver disease than that seen with either disease alone. However, the activity of HCV infection seems to be partially suppressed in patients with SLD.

Intracerebroventricular administration of somatostatin prevents and attenuates adjuvant arthritis

The effects of somatostatin on the development of adjuvant arthritis induced by Mycobacterium butyricum were studied. Somatostatin was injected into the lateral cerebral ventricle every day for 14 days beginning on the first day of mycobacteria inoculation in the preventive group. In the treatment group, somatostatin was injected from day 17 until day 30 post-mycobacteria inoculation. Arthritis was evaluated by measuring ankle joint circumference and diameter as well as microscopic examination of ankle joint sections. Somatostatin profoundly inhibited the development of adjuvant arthritis and an anti-inflammatory action was observed in the treatment group. These results suggest that somatostatin has a central action that can prevent or attenuate symptoms associated with arthritis.

Intestinal parasitic diseases in Riyadh, Saudi Arabia: prevalence, sociodemographic and environmental associates

Our objectives were to assess the prevalence of intestinal parasitic infections in Riyadh and to determine associated sociodemographic and environmental factors. The study was conducted through a household survey. Three health centres were chosen from each of the five Riyadh urban regions and 15 from rural areas. Based on the average family size, a random sample of households were chosen. All household members were asked to participate in the study. Data were collected using a pre-designed questionnaire eliciting data on sociodemographic and environmental factors. A stool specimen of each individual was examined microscopically for the presence of trophozoites and cysts. Six thousand and twelve participants with a mean age of 23.3 +/- 17.4 (median 19 years, 48.6% males) were studied and 32.2% were infected. The infection rate was high in urban areas (33.3%), among children < 12 years (34.4%), non-Saudis (42.2%), single persons (34.9%), illiterate individuals (33.8%), those who obtained drinking water from tankers (36.1%) and those who disposed of sewage in open channels (47.1%). Stratified analysis showed that for Saudis <12 years parasitic infections were significantly higher among tanker users (39.5%) and septic tank users (36.8%). For Saudis> or =12 years low education, water storage and open sewage disposal were statistically associated with parasitic infections (P < 0.05). Among expatriates, infections were high among males (47.6%), urban residents (48.3%), single persons (46.9%), tanker users (39.5%) and septic tank users (78.6%). Multivariate logistic regression analysis showed that age < 12 years, non-Saudi nationalities, educational level below secondary school, tanker as source of water and open sewage disposal were independently associated with high intestinal parasitic infection.

RANTES promotes growth and survival of human first-trimester forebrain astrocytes

We have examined the role of alpha and beta chemokines in the promotion of the ontogenetic development of the brain. RANTES was expressed preferentially in human fetal astrocytes in an age-dependent manner. Astrocytes from 5-week-old brains showed high proliferation and reduced survival, whereas 10-week-old astrocytes exhibited opposite effects. These effects were suppressed by anti-RANTES or anti-RANTES receptor antibodies and were enhanced by recombinant RANTES. RANTES induced tyrosine phosphorylation of several cellular proteins and nuclear translocation of STAT-1 in astrocytes. Interferon-gamma (IFN-gamma) was required for RANTES effects because RANTES induced IFN-gamma and only 10-week-old astrocytes expressed the IFN-gamma receptor. Blocking of IFN-gamma with antibody reversed the effects of RANTES, indicating that cytokine/chemokine networks are critically involved in brain development.

Intracerebroventricular met-enkephalin administration modulates adjuvant arthritis

The purpose of this study was to investigate the anti-inflammatory properties of intracerebroventricular met-enkephalin (met-enk) administration in an animal model of arthritis. Adjuvant arthritis was induced in rats by intradermal inoculation of mycobacterium butyricum and the effects of intraventricular met-enk+thiorphan (enkephalinase inhibitor) were studied. Treatment was initiated either simultaneously with the bacterial inoculation (preventive group) or on post-inoculation day 17 after the appearance of inflammation (treatment group). The degree of inflammation was evaluated by measuring the diameter and the circumference of the ankle joint immediately before the sacrifice (day 31) and by histologic examination of ankle joint sections. The results of this study revealed that combined intraventricular injections of met-enk+thiorphan reduced the arthritic-like inflammation in the preventive group as well as in the treatment group. These findings suggest that centrally applied met-enk+thiorphan may suppress the development adjuvant arthritis as well as the symptoms of manifest arthritis. Thus central met-enk may be involved in both hypothalamic pituitary adrenal axis and immune forms of stress-induced modulation.

Allelic loss is heterogeneous throughout the tumor in colorectal carcinoma

BACKGROUND

Loss of heterozygosity (LOH) at 17p and 18q in colorectal carcinoma has been depicted as a potential prognostic marker for the disease. However, conclusions vary among reports, and evidence of clinically useful genetic prognostic markers is still lacking. As a rule, single biopsies are used. In this study, the authors hypothesized that an important cause of earlier contradictory results was the heterogeneity of colorectal neoplasms.

METHODS

In this study, DNA originating in each quadrant of tumors from 64 patients with colorectal carcinoma was analyzed. Microsatellite markers for chromosome 18q and 17p were amplified by polymerase chain reaction and automatically analyzed.

RESULTS

The authors found that, regardless of stage, LOH and non-LOH in both 17p and 18q varied among biopsies within the tumors in a random fashion. LOH in 18q was detected in all 4 quadrants in 22% and in 1 of 4, 2 of 4, or 3 of 4 quadrants in 56% of the tumors, whereas 22% of the tumors were homogeneously without LOH in 18q. LOH 17p was distributed similarly throughout the tumors and was present in 1 of 4, 2 of 4, or 3 of 4 of the quadrants in 44%. The authors also reexamined a subset of tumors by subdividing one biopsy from each into four. Analysis of the microsatellite markers then yielded identical results. No correlation between the degree of LOH status and patient survival was observed.

CONCLUSIONS

LOH status within a colorectal tumor is extensively heterogeneous. However, it is more homologous on a lower macroscopic level. For relevant genetic analysis, multiple biopsies and DNA sampling preceded by careful morphologic examination must be standard in the preparation of DNA.

Modes of adherence of Helicobacter pylori to gastric surface epithelium in gastroduodenal disease: a possible sequence of events leading to internalisation

We have investigated various modes of adherence of Helicobacter pylori to the human gastric epithelium, using transmission electron microscopy, in biopsies from nine patients with peptic ulcer disease and from four patients with chronic active gastritis. H. pylori was demonstrated in abundance in all cases within the surface mucous layer. In all ulcer- and in one out of four gastritis patients H. pylori was shown in close proximity to the gastric epithelium, with concurrent alterations in the configuration of microvilli and the apical cytoplasmic region of gastric cells. Previously described modes of H. pylori adherence were confirmed, such as loose attachment with fibrillar-like strands, firm attachment with pedestal formation, invasion in the intercellular spaces, and invagination with "cup" formation. Moreover, in many cases a fusion between the bacterial outer layer and gastric cell membranes was evident. In four cases (31%; three with active and one with past ulcer disease) viable H. pylori was found in the cytoplasm of gastric mucous cells. Our results support the hypothesis that the different modes of adherence of H. pylori represent a stepwise, possibly sequential, process which in a significant number of cases leads to internalisation of the organism. The invariable occurrence of adhesion and more frequent internalisation of H. pylori in ulcer patients may suggest a link with the pathogenesis of peptic ulcer disease.

Clinical significance of TT virus infection in patients with chronic liver disease and volunteer blood donors in Egypt

Clinical significance of TT virus (TTV) infection was investigated in Egyptian patients with chronic liver disease and volunteer blood donors by a cross sectional analysis. TTV DNA in serum was assessed by a semi-nested polymerase chain reaction. The prevalence of TTV DNA did not differ among patients with chronic hepatitis B (11/24, 46%), chronic hepatitis C (22/72, 31%), or schistosomal liver disease (14/39, 36%). No difference in prevalence was found between blood donors (32/109, 29%) and each of the patient groups. Clinical background including mean age, sex distribution, history of blood transfusion, and mean level of alanine aminotransferase did not differ between TTV DNA-positive and -negative individuals in any of the study groups. Ultrasonographic evidence of liver cirrhosis was similar between TTV-positive and -negative patients in each of the chronic liver disease groups. TTV infection was not associated with hepatitis B or C virus infection in blood donors. The only significant difference observed was the lower concentration of serum HCV RNA in TTV DNA positive compared with negative patients with chronic hepatitis C (3.0 +/- 1.4 vs. 4.0 +/- 0.9 log copies/ml, P <. 001). In conclusion, TTV infection was not associated with either past history of blood exposure or infection with bloodborne hepatitis viruses in Egypt. No clinical significance of TTV was found in the present study. However, a reciprocal interaction was suggested between TTV and HCV replication.

Sensitivity and specificity of planar scintimammography with 99mTc-sestamibi

PURPOSE

The aim of our prospective study was to determine the diagnostic accuracy of planar breast imaging with 99mTc-MIBI in detecting malignant disease.

MATERIAL AND METHODS

Ninety-six consecutive patients with 121 clinically- and/or mammographically-detected breast lesions underwent preoperative planar scintimammography. Ten minutes after injection of 700 MBq 99mTc-MIBI, two lateral prone and one anterior supine projections with an acquisition time of 8 minutes each were obtained. Interpretation of scintimammographic results was made blindly and any focal accumulation of MIBI in the breasts was the criterion for an abnormal scintigram. All lesions were operated on and histologically verified.

RESULTS

Histologically, 86 malignant and 35 benign lesions were found in 121 breast lesions. A sensitivity of 83.7% and a specificity of 74.2% for malignancy was achieved at planar scintimammography.

CONCLUSION

Scintimammography with 99mTc-MIBI is an imaging modality of modest usefulness in the investigation of breast lesions. The method has a low sensitivity in lesions smaller than 10 mm in diameter, which decreases the clinical use of the method.