Retention of latent centromeres in the Mammalian genome.

The centromere is a cytologically defined entity that possesses a conserved and restricted function in the cell: it is the site of kinetochore assembly and spindle attachment. Despite its conserved function, the centromere is a highly mutable portion of the chromosome, carrying little sequence conservation across taxa. This divergence has made studying the movement of a centromere, either within a single karyotype or between species, a challenging endeavor. Several hypotheses have been proposed to explain the permutability of centromere location within a chromosome. This permutability is termed "centromere repositioning" when described in an evolutionary context and "neocentromerization" when abnormalities within an individual karyotype are considered. Both are characterized by a shift in location of the functional centromere within a chromosome without a concomitant change in linear gene order. Evolutionary studies across lineages clearly indicate that centromere repositioning is not a rare event in karyotypic evolution and must be considered when examining the evolution of chromosome structure and syntenic order. This paper examines the theories proposed to explain centromere repositioning in mammals. These theories are interpreted in light of evidence gained in human studies and in our presented data from the marsupial model species Macropus eugenii, the tammar wallaby.

Effect of pneumoperitoneal pressure on tumor dissemination and tumor recurrence at port-site and midline incisions.

Over the past several years numerous cases of port site tumor recurrence after laparoscopic resection of a cancerous tissue have been reported. Possible mechanisms for tumor seeding include tumor removal, contaminated instruments, pneumoperitoneum, and aerosolization of tumor cells. This experiment examined the relationship among trocar contamination, aerosolization, and tumor recurrence with increasing pneumoperitoneal pressure using a hamster model. Increased pneumoperitoneal pressure significantly increased both instrument contamination and tumor recurrence at midline and port site incisions. Interestingly, increasing pneumoperitoneal pressure had no significant effect on the number of aerosolized tumor cells. The results reaffirm that the use of a reduced pneumoperitoneum or gasless laparoscopy may significantly lower port site tumor recurrence.

Naked cuticle targets dishevelled to antagonize Wnt signal transduction.

In Drosophila embryos the protein Naked cuticle (Nkd) limits the effects of the Wnt signal Wingless (Wg) during early segmentation. nkd loss of function results in segment polarity defects and embryonic death, but how nkd affects Wnt signaling is unknown. Using ectopic expression, we find that Nkd affects, in a cell-autonomous manner, a transduction step between the Wnt signaling components Dishevelled (Dsh) and Zeste-white 3 kinase (Zw3). Zw3 is essential for repressing Wg target-gene transcription in the absence of a Wg signal, and the role of Wg is to relieve this inhibition. Our double-mutant analysis shows that, in contrast to Zw3, Nkd acts when the Wg pathway is active to restrain signal transduction. Yeast two hybrid and in vitro experiments indicate that Nkd directly binds to the basic-PDZ region of Dsh. Specially timed Nkd overexpression is capable of abolishing Dsh function in a distinct signaling pathway that controls planar-cell polarity. Our results suggest that Nkd acts directly through Dsh to limit Wg activity and thus determines how efficiently Wnt signals stabilize Armadillo (Arm)/beta-catenin and activate downstream genes.

naked cuticle encodes an inducible antagonist of Wnt signalling.

During animal development, cells have to respond appropriately to localized secreted signals. Proper responses to Hedgehog, transforming growth factor-beta, epidermal growth factor and fibroblast growth factor/Ras signals require cognate inducible antagonists such as Patched, Dad, Argos and Sprouty. Wnt signals are crucial in development and neoplasia. Here we show that naked cuticle (nkd), a Drosophila segment-polarity gene, encodes an inducible antagonist for the Wnt signal Wingless (Wg). In fly embryos and imaginal discs nkd transcription is induced by Wg. In embryos, decreased nkd function has an effect similar to excess Wg; at later stages such a decrease appears to have no effect. Conversely, overproduction of Nkd in Drosophila and misexpression of Nkd in the vertebrate Xenopus laevis result in phenotypes resembling those of loss of Wg/Wnt function. nkd encodes a protein with a single EF hand (a calcium-binding motif) that is most similar to the recoverin family of myristoyl switch proteins. Nkd may therefore link ion fluxes to the regulation of the potency, duration or distribution of Wnt signals. Signal-inducible feedback antagonists such as nkd may limit the effects of Wnt proteins in development and disease.

Outcomes of coronary artery bypass grafting: a 3 year analysis using the Society of Thoracic Surgeons Database.

BACKGROUND: Accurate risk factor analysis is a critical element in contemporary cardiac surgical practice. In the USA, the Society of Thoracic Surgeons Database allows institutions and individual surgeons to carry out detailed patient risk assessment and to review their cardiac surgical outcomes in a comparative fashion. METHODS: To evaluate outcomes of isolated coronary artery bypass grafting, data from all patients operated upon at the Alfred Hospital, Melbourne, Australia, over a 3 year period were entered into the Society of Thoracic Surgeons Database. RESULTS: Our results (mortality and morbidity) compared favourably with those contained within this large international database. CONCLUSION: It is hoped that a similar Australasian database can be established to facilitate a meaningful local risk assessment and a comparative analysis of outcomes of cardiac surgical procedures.

Mobile element 297 in the Abd-B gene of Drosophila melanogaster, not Delta 88, is responsible for the tuh-3 mutation.

The tumorous-head-3 (tuh-3) mutation has been associated with the insertion of mobile element Delta 88 at +200 on the bithorax complex (BX-C) DNA map, 5' of all Abdominal-B (Abd-B) transcripts. Different phenotypes of tuh-3 are regulated by the tumorous-head-1 (tuh-1) maternal effect locus. In the presence of the recessive tuh-1h maternal effect, tuh-3 offspring produce homeotic abdominal and genital tissue in the head. In the presence of the dominant tuh-1g maternal effect, tuh-3 offspring have normal heads but now show genital defects. One other mutant, I127B, produces flies with identical defects to that of tuh-3 in the presence of both maternal effects. Molecular analysis of I127B revealed the insertion of mobile element 297 in the Abd-B gene, approximately 25 kb downstream of the Delta 88 insertion in tuh-3. No other abnormalities were detected. Reexamination of our tuh-3 strain revealed a 297 insertion in an identical region to that of I127B, in addition to the Delta 88 insertion. Recombinants of tuh-3, carrying 297 only, produced homeotic head defects and genital defects in the presence of the tuh-1h and tuh-1g maternal effects, respectively. Recombinants of tuh-3, carrying Delta 88 only, failed to produce any defects in the presence of either maternal effect. Based upon these results, we propose that it is the 297 insertion in the Abd-B gene, not Delta 88, that is responsible for the tuh-3 mutation.

Analysis of the genes involved in organizing the tail segments of the Drosophila melanogaster embryo.

The metameric organization of the Drosophila melanogaster tail is obscured by developmental events that partially suppress or fuse some of its regions. To better define the developmental origins and segmental identities in the tail of the Drosophila embryo, we documented expression patterns and mutant phenotypes of several genes that play important roles in its morphogenesis. We documented the domains of engrailed (en), Abdominal-B (Abd-B) and caudal (cad) expression in the tail region. The staining pattern of cut (ct) was used to correlate the embryonic sense organs with their respective positions on the larval cuticle. The en patterns in different Bithorax-Complex (BX-C) Abd-B morphogenetic (m) and regulatory (r) mutants demonstrated that Abd-B functions to, among other things, suppress embryonic ventral epidermal structures on the posterior side of A8 to A9. Ventral epidermal structures were not added back into the en pattern in r- or BX-C- mutants, indicating that although the BX-C functions extend through A10, other non-BX-C genes must be required for development of this segment.

The "Ozone Deficit" Problem: O2(X, v ge 26) + O(3P) from 226-nm Ozone Photodissociation.

Highly vibrationally excited O(2)(X(3)sigmag(-), v >/= 26) has been observed from the photodissociation of ozone (O(3)), and the quantum yield for this reaction has been determined for excitation at 226 nanometers. This observation may help to address the "ozone deficit" problem, or why the previously predicted stratospheric O(3) concentration is less than that observed. Recent kinetic studies have suggested that O(2)(X(3)sigmag(-), v >/= 26) can react rapidly with O(2) to form O(3) + O and have led to speculation that, if produced in the photodissociation of O(3), this species might be involved in resolving the discrepancy. The sequence O(3) + hv --> O(2)(X(3)sigmag(-), v >/= 26) + O; O(2)(X(3)sigmag(-), v >/= 26) + O(2) --> O(3) + O (where hv is a photon) would be an autocatalytic mechanism for production of odd oxygen. A two-dimensional atmospheric model has been used to evaluate the importance of this new mechanism. The new mechanism can completely account for the tropical O(3) deficit at an altitude of 43 kilometers, but it does not completely account for the deficit at higher altitudes. The mechanism also provides for isotopic fractionation and may contribute to an explanation for the anomalously high concentration of heavy O(3) in the stratosphere.

How to reduce your inventory: a real world case study.

This case study describes the use of a performance analysis system at the Safety Products Division of Mine Safety Appliances Company, which contributed to the reduction of excess inventories by more than $8,000,000 during the first two years of implementation.

Analysis of the roles of antilipopolysaccharide and anti-cholera toxin immunoglobulin A (IgA) antibodies in protection against Vibrio cholerae and cholera toxin by use of monoclonal IgA antibodies in vivo.

Secretory immunoglobulin A (IgA) antibodies (sIgA) directed against cholera toxin (CT) and surface components of Vibrio cholerae are associated with protection against cholera, but the relative importance of specific sIgAs in protection is unknown. A monoclonal IgA directed against the V. cholerae lipopolysaccharide (LPS), secreted into the intestines of neonatal mice bearing hybridoma tumors, was previously shown to provide protection against a lethal oral dose of 10(7) V. cholerae cells. We show here that a single oral dose of 5 to 50 micrograms of the monoclonal anti-LPS IgA, given within 2 h before V. cholerae challenge, protected neonatal mice against challenge. In contrast, an oral dose of 80 micrograms of monoclonal IgA directed against CT B subunit (CTB) failed to protect against V. cholerae challenge. A total of 80 micrograms of monoclonal anti-CTB IgA given orally protected neonatal mice from a lethal (5-micrograms) oral dose of CT. Secretion of the same anti-CTB IgA antibodies into the intestines of mice bearing IgA hybridoma backpack tumors, however, failed to protect against lethal oral doses of either CT (5 micrograms) or V. cholerae (10(7) cells). Furthermore, monoclonal anti-CTB IgA, either delivered orally or secreted onto mucosal surfaces in mice bearing hybridoma tumors, did not significantly enhance protection over that provided by oral anti-LPS IgA alone. These results demonstrate that anti-LPS sIgA is much more effective than anti-CT IgA in prevention of V. cholerae-induced diarrheal disease.

Tumorous-head (tuh-1; tuh-3) modulates Abd-B bithorax-complex functions in Drosophila melanogaster.

Abdominal-B (Abd-B) mutants of the bithorax-complex (BX-C) were studied in trans with tuh-3 to evaluate their interactions with this homeotic mutant and the maternal effect locus (tuh-1) controlling tuh-3 expression. Head defects occur in tuh-3 offspring from tuh-1h homozygous mothers, while genital defects occur in homozygous tuh-3 offspring from mothers carrying the tuh-1g allele. The influence exerted by the tuh-1 maternal effects on tuh-3 Abd-B transcript distribution was evaluated by whole mount in situ hybridization. Results demonstrated that: (1) of the 21 Abd-B mutants tested, head defects were produced by SGA62, I127B, I127O and tuh-3, with I127B and tuh-3 as the only mutants to require the head defect maternal effect for expression; (2) one specific cluster of regulatory (r) mutants, Uab1, 65 and I127B, enhanced penetrance and expressivity of tuh-3 head defects; (3) the most profound suppression of head defect penetrance occurred when Abd-B mutants eliminated the morphogenetic (m) and r functions; (4) genital defects increased in frequency in tuh-3/Abd-B mutant trans-heterozygotes with loss of r function; (5) Abd-B transcription (class A, class B, class C) appears normal in tuh-3 embryos when their mothers pass on the tuh-1h head defect maternal effect, whereas the regulatory transcripts (class B and class C) are reduced when tuh-3 mothers pass on the tuh-1g genital disc maternal effect; (5) tuh eye-antennal imaginal discs express ABD-B protein; and (6) tuh-3 misregulates both m and r function of Abd-B.

Development of the D. melanogaster caudal segments involves suppression of the ventral regions of A8, A9 and A10.

Whereas the segmental organization of the thorax and anterior abdomen is morphologically delineated in both the Drosophila larva and adult, segments in the head and caudal regions lack such well-defined boundaries. Consequently, the organization of these regions has been difficult to decipher. In this study, transformations caused by the bithorax-complex homeotic mutants 48, M3, Ultraabdominal-1 (Uab1) and tumorous-head-3 (tuh-3), as well as the patterns of engrailed gene expression have been analyzed to investigate the segmental organization of the caudal segments. A special emphasis was placed on sense organs appearing in abdominal segments 8, 9 and 10 (A8-A10): We find that: (1) transformations in the caudal segments obey parasegmental borders; (2) the sense organs on A8, A9, and A10 are probably homologous to the pits and hairs in anterior A1-A7; (3) except for the larval anal tuft and the anterior side of A8, all structures in larval segments A8, A9 and A10 are dorsal/lateral in origin; and (4) dorsalization of embryonic A8 and A9 cells leaves space ventrally for A10, as it follows the contracting ventral nervous system during the embryological process of germ band contraction.

Membrane domains of intestinal epithelial cells: distribution of Na+,K+-ATPase and the membrane skeleton in adult rat intestine during fetal development and after epithelial isolation.

The organization of the basolateral membrane domain of highly polarized intestinal absorptive cells was studied in adult rat intestinal mucosa, during development of polarity in fetal intestine, and in isolated epithelial sheets. Semi-thin frozen sections of these tissues were stained with a monoclonal antibody (mAb 4C4) directed against Na+,K+-ATPase, and with other reagents to visualize distributions of the membrane skeleton (fodrin), an epithelial cell adhesion molecule (uvomorulin), an apical membrane enzyme (aminopeptidase), and filamentous actin. In intact adult epithelium, Na+,K+-ATPase, membrane-associated fodrin, and uvomorulin were concentrated in the lateral, but not basal, subdomain. In the stratified epithelium of fetal intestine, both fodrin and uvomorulin were localized in areas of cell-cell contact at 16 and 17 d gestation, a stage when Na+,K+-ATPase was not yet expressed. These molecules were excluded from apical domains and from cell surfaces in contact with basal lamina. When Na+,K+-ATPase appeared at 18-19 d, it was codistributed with fodrin. Detachment of epithelial sheets from adult intestinal mucosa did not disrupt intercellular junctions or lateral cell contacts, but cytoplasmic blebs appeared at basal cell surfaces, and a diffuse pool of fodrin and actin accumulated in them. At the same time, Na+,K+-ATPase moved into the basal membrane subdomain, and extensive endocytosis of basolateral membrane, including Na+,K+-ATPase, occurred. Endocytosis of uvomorulin was not detected and no fodrin was associated with endocytic vesicles. Uvomorulin, along with some membrane-associated fodrin and some Na+,K+-ATPase, remained in the lateral membrane as long as intercellular contacts were maintained. Thus, in this polarized epithelium, interaction of lateral cell-cell adhesion molecules as well as basal cell-substrate interactions are required for maintaining the stability of the lateral membrane skeleton and the position of resident membrane proteins concentrated in the lateral membrane domain.

Beta-adrenoceptor-mediated modulation of calcium ionophore activated polymorphonuclear leucocytes.

Beta-adrenoceptor-mediated modulation of calcium-mediated stimulus-response coupling was studied using calcium ionophore (A23187) activation of polymorphonuclear leucocytes (PMNL). Oxygen metabolite generation was measured with luminol- and lucigenin-dependent chemiluminescence in both whole blood and isolated PMNL. Isoprenaline reduced PMNL response by 53% in a dose-dependent fashion. The effect was saturable, stereoselective, antagonized by propranolol and significant at isoprenaline concentrations as low as 0.01 nM. Fifty % maximal response was induced by 0.26 nM, 3 nM, and 125 nM isoprenaline, adrenaline and noradrenaline respectively. Because the effects of beta-adrenoceptor agonists in PMNL have not consistently correlated with measurements of cyclic AMP, alternative means of increasing cyclic AMP were studied. Forskolin and dibutyryl cyclic AMP inhibited PMNL with significant effects at 1.0 microM and 10 microM respectively. The effects of beta-adrenoceptor agonists were much greater when PMNL were activated by calcium ionophore compared with opsonized zymosan. Isoprenaline had no effect upon 1-oleoyl-2-acetylglycerol activated PMNL. Because catecholamine modulation of oxygen metabolite generation can be characterized pharmacologically, PMNL activation by calcium ionophore is an excellent model for study of beta-adrenoceptor function in viable human cells. In contrast to previously described beta-adrenoceptor agonist modulation of PMNL function, inhibition of calcium-mediated activation is significant at physiological concentrations. The clinical consequences of such catecholamine effects are dependent upon the mechanism of PMNL activation in a specific circumstance.

[Organized and professional crime: a comparative approach]. / Delitto organizzato e delitto professionale: un approccio comparativo

After a short preliminary statement of a terminological character, the authors review the basic features of professional and organized crime, also in relation to historically well defined aspects of it, of the "crime-syndicate" type. The tracts differentiating in this sector the European criminality from the North-American one are identified, and the most significant examples of criminal organization active in recent times especially in Great Britain are illustrated. The survey is carried out taking into account the quantitative and qualitative evolution of the phenomenon and probing further into the value and function that the various categories of crime operators assume in the most modern forms of organized crime. A special attention is devoted to the activities of particular importance that precede and follow the perpetration of crimes. The problem of the professional and organized crime is also viewed in the light of the difference existing in the various European countries, and of the easy access to international connections which afford to this type of crime quite a comprehensive scope of action and which involve a greater difficulty of the activities carried out by the authorities of the various countries. The authors finally emphasize the gravity of the new forms of crime that are being committed especially in the business field, and urge all those concerned in criminological problems to devote their attention to the phenomenon, delving further into the connection it has with the deviance theory.