Fluorescence studies on the binding between 1-47 fragment of cholecystokinin receptor CCK(A)-R(1-47) and nonsulfated cholecystokinin octapeptide CCK8

The interaction between the 1-47 N-terminus fragment of the cholecystokinin receptor and the nonsulfated cholecystokinin octapeptide, CCK8, is monitored by fluorescence emission. Quenching of the fluorescence intensities is observed on binding. Dissociation constants calculated by these data are in the same submicromolar range as found for the binding of linear CCK8 analogues to B-type receptors. Although detailed structural information cannot be obtained, fluorescence emission is more sensitive than other techniques and permits fast detection of receptor-ligand interaction.

Regional lymph node dissection in the treatment of renal cell carcinoma: is it useful in patients with no suspected adenopathy before or during surgery?

OBJECTIVES

To evaluate the role of regional lymph node dissection (LND) in a series of patients with renal cell carcinoma (RCC) with no suspicion of nodal metastases before or during surgery.

PATIENTS AND METHODS

A series of 167 patients with RCC, free from distant metastases at diagnosis, and who underwent radical nephrectomy at our hospital between January 1990 and October 1997, was reviewed. The mean (median, range) follow-up was 51 (45, 19-112) months. Of the 167 patients, 108 underwent radical nephrectomy alone and 59 had radical nephrectomy with regional LND limited to the anterior, posterior and lateral sides of the ipsilateral great vessel, from the level of the renal pedicle to the inferior mesenteric artery. Of these 59 patients, 49 had no evidence of nodal metastases before or during surgery. The probability of survival was estimated by the Kaplan-Meier method, using the log-rank test to estimate differences among levels of the analysed variables.

RESULTS

The overall 5-year survival was 79%; the 5-year survival rate for the 108 patients who underwent radical nephrectomy alone was 79% and for the 49 who underwent LND was 78%. Of the 49 patients with no suspicion of lymph node metastases, one (2%) was found to have histologically confirmed positive nodes.

CONCLUSION

These results suggest that there is no clinical benefit in terms of overall outcome in undertaking regional LND in the absence of enlarged nodes detected before or during surgery.

Synthesis and solution characterization of a porphyrin-CCK8 conjugate

In this paper we report the synthesis and a detailed NMR solution characterization of a new CCK8 analogue and its indium(III) complex, PK-CCK8 and In-PK-CCK8. The new compounds contain a porphyrin moiety covalently bound through an amide bond to the side chain of a Lys residue introduced at the N-terminus of CCK8. A molecular dynamics simulation, based on the NMR structure of the complex between CCK8 and the N-terminal extracellular arm of the CCK(A) receptor, is also reported. Both the NMR study and the molecular dynamics simulation indicate that the porphyrin-peptide conjugate might be able to bind to the CCK(A) receptor model. The results of the molecular dynamics calculations show that the conformational features of the CCK8/CCK(A) receptor model complex and of the PK-CCK8/CCK(A) receptor-model complex are similar. This evidence supports the view that the introduction of the porphyrin-Lys moiety does not influence the mode of ligand binding to the CCK(A) receptor model. The NMR structure of PK-CCK8 in DMSO consists of a well defined pseudo-helical N-terminal region, while the C-terminal region is flexible. Moreover, the absence of NOE contacts between the porphyrin and the peptide indicates that the macrocyclic ring is directed away from the peptide region involved in the binding with the receptor.

Older adult multiorgan donors and misdiagnosed tumor

BACKGROUND

In these last years, the increase in organ donations is mostly due to old patients died of primary vascular cerebral diseases. In this kind of patients some undiagnosed cancers can be present and can be transmitted to the receiver. Aim of this study is to carry out a research in order to identify any undiagnosed cancer which can be present during the period of encephalic death.

METHODS

Perspective study: hospitals type II and type III. Polyvalent intensive care. From January 1999 to July 2000 encephalic death has been ascertained in 16 patients. The research of tumor markers has been carried out on these patients. Further diagnostic researches have been carried out on patients who had anomalous values.

RESULTS

The organ donations have not been made by eight patients: five for family refusal, one for medical contraindications, two for the presence of undiagnosed tumor (PSA 1100 ng/ml and CEA 129.5 ng/ml) confirmed by prostatic and abdominal US imaging. A patient with CA 19-9 89.5 ng/ml has not been examined, because of the family refusal to donation. A patient with PSA of 135 ng/ml had a negative response from the anal scanner, and so the prosecution of the donation has not been interrupted. A blood sample has been taken and a biopsy of the prostate has been made to confirm the absence of neoplasm.

CONCLUSIONS

It is necessary to make a careful examination of the organ donor to check if some cancers are present. Tumor markers cannot be used to make a diagnosis of a cancer, but they can be used as guide for further researches. In spite of all the diagnostic efforts, the objective evaluation of the surgeon is still the most important factor like the biopsy of all the suspected lesions during an operation and the autopsy.

The arabidopsis ATHB-8 HD-zip protein acts as a differentiation-promoting transcription factor of the vascular meristems

ATHB-8, -9, -14, -15, and IFL1/REV are members of a small homeodomain-leucine zipper family whose genes are characterized by expression in the vascular tissue. ATHB-8, a gene positively regulated by auxin (Baima et al., 1995), is considered an early marker of the procambial cells and of the cambium during vascular regeneration after wounding. Here, we demonstrate that although the formation of the vascular system is not affected in athb8 mutants, ectopic expression of ATHB-8 in Arabidopsis plants increased the production of xylem tissue. In particular, a careful anatomical analysis of the transgenic plants indicated that the overexpression of ATHB-8 promotes vascular cell differentiation. First, the procambial cells differentiated precociously into primary xylem. In addition, interfascicular cells also differentiated precociously into fibers. Finally, the transition to secondary growth, mainly producing xylem, was anticipated in transgenic inflorescence stems compared with controls. The stimulation of primary and secondary vascular cell differentiation resulted in complex modifications of the growth and development of the ATHB-8 transgenic plants. Taken together, these results are consistent with the hypothesis that ATHB-8 is a positive regulator of proliferation and differentiation, and participates in a positive feedback loop in which auxin signaling induces the expression of ATHB-8, which in turn positively modulates the activity of procambial and cambial cells to differentiate.

The effect of a paracetamol and morphine combination on dynorphin A levels in the rat brain

The purpose of this study was to find out whether the combination of inactive doses of paracetamol (PARA) and morphine was able to change dynorphin (DYN) A levels, evaluated by radioimmunoassay, and whether naloxone or [(-)-2-(3 furylmethyl)-normetazocine] (MR 2266), a kappa-opioid antagonist, modifies or prevents the activity of this combination on nociception and on DYN levels. The work was suggested by our previous findings which demonstrated that inactive doses of PARA and morphine, when given in combination, share an antinociceptive effect, and that PARA, at antinociceptive doses, decreases DYN levels in the frontal cortex, thus indicating a selective action within the CNS. Our present results demonstrate that the combination of inactive doses of PARA (100 mg/kg) and morphine (3 mg/kg) is just as effective in decreasing the levels of DYN A as full antinociceptive doses of PARA or morphine alone in the frontal cortex of the rat. The values, expressed in pmol/g tissue, were: control = 2.83 +/- 0.20; paracetamol (100) = 2.60 +/- 0.23; morphine (3) = 2.73 +/- 0.24; paracetamol + morphine = 1.34 + 0.16 (P < 0.05). The decrease was partially antagonised by MR 2266, but not by naloxone, suggesting that the activity of PARA and morphine in combination on DYN A levels could be mediated, at least in part, through kappa-receptors, although other systems may be involved. On the other hand, both naloxone and MR 2266 prevented the antinociceptive effect of the combination in the hot plate test. All our experimental data suggest that PARA and morphine in combination exert their antinociceptive effect through the opioidergic system, which in turn may cause a decrease in DYN levels in the CNS of the rat.

Fit genotypes and escape variants of subgroup III Neisseria meningitidis during three pandemics of epidemic meningitis

The genetic variability at six polymorphic loci was examined within a global collection of 502 isolates of subgroup III, serogroup A Neisseria meningitidis. Nine "genoclouds" were identified, consisting of genotypes that were isolated repeatedly plus 48 descendent genotypes that were isolated rarely. These genoclouds have caused three pandemic waves of disease since the mid-1960s, the most recent of which was imported from East Asia to Europe and Africa in the mid-1990s. Many of the genotypes are escape variants, resulting from positive selection that we attribute to herd immunity. Despite positive selection, most escape variants are less fit than their parents and are lost because of competition and bottlenecks during spread from country to country. Competition between fit genotypes results in dramatic changes in population composition over short time periods.

The effect of paracetamol on nociception and dynorphin A levels in the rat brain

Male Wistar rats were administered with naloxone (1 mg/kg i.p.) or MR 2266 (5 mg/kg i.p) 15 min before paracetamol (400 mg/kg i.p.) treatment and the pain threshold was evaluated. Rats were subjected to the hot-plate and formalin tests and immunoreactive dynorphin A (ir-dynorphin A) levels were measured in the hypothalamus, hippocampus, striatum, brainstem, frontal and parietal-temporal cortex by radioimmunoassay. Pretreatment with naloxone abolished paracetamol antinociceptive activity both in hot-plate and in the first phase, but not in the second phase of the formalin test, while MR 2266 pretreatment was able to antagonise paracetamol effect either in the hot-plate test or in both phases of the formalin test. Among different brain areas investigated paracetamol significantly decreased ir-dynorphin A levels only in the frontal cortex. MR 2266 but not naloxone reversed the decrease in ir-dynorphin A levels elicited by paracetamol. Paracetamol seems to exert its antinociceptive effect also through the opioidergic system modulating dynorphin release in the central nervous system (CNS) of the rat, as suggested by the decrease in the peptide levels.

Negative autoregulation of the Arabidopsis homeobox gene ATHB-2

The Arabidopsis homeobox gene ATHB-2 is tightly regulated by light signals, and is thought to direct morphological changes during shade avoidance responses. To understand how ATHB-2 mediates light signals in plant morphogenesis, we investigated its transcriptional network. We constructed a gene encoding a chimeric transcription factor (HD-Zip-2-V-G) that is expected to activate target genes of ATHB-2 in a glucocorticoid-dependent manner. In transgenic Arabidopsis plants expressing HD-Zip-2-V-G, glucocorticoid treatment activates the ATHB-2 gene itself, independent of de novo protein synthesis. An in vitro DNase I-footprinting experiment showed that recombinant ATHB-2 protein specifically bound to an ATHB-2 promoter region. These complementary results indicate that ATHB-2 recognizes its own promoter. Consistent with the fact that ATHB-2 itself has been shown to act as a repressor, expression of the endogenous ATHB-2 gene was repressed in transgenic plants overexpressing an ATHB-2 transgene. Moreover, target-gene analysis using the HD-Zip-2-V-G suggested that ATHB-2 recognizes other HD-Zip II subfamily genes. We conclude that ATHB-2 has a negative autoregulatory loop and may be involved in a complicated transcriptional network involving paralogous genes, as is the case with animal homeobox genes.

Molecular epidemiology of serogroup a meningitis in Moscow, 1969 to 1997

Molecular analysis of 103 serogroup A Neisseria meningitidis strains isolated in Moscow from 1969 to 1997 showed that four independent clonal groupings were responsible for successive waves of meningococcal disease. An epidemic from 1969 to the mid-1970s was caused by genocloud 2 of subgroup III, possibly imported from China. Subsequent endemic disease through the early 1990s was caused by subgroup X and then by subgroup VI, which has also caused endemic disease elsewhere in eastern Europe. A 1996 epidemic was part of the pandemic spread from Asia of genocloud 8 of subgroup III. Recent genocloud 8 epidemic disease in Moscow may represent an early warning for spread of these bacteria to other countries in Europe.

Pulsed-field gel electrophoresis

DNA molecules in an agarose matrix elongate and migrate toward the anode when exposed to an electric field. An agarose matrix represents a highly irregular network with pores of various dimensions, large open areas, and regions with different densities. During electrophoresis, migration will be retarded by obstructions that prevent sieving by size and result in "end-on" migration as if through a sinuous tube ("reptation" [1]). The limit of resolution is reached when the radius of gyration of the linear DNA exceeds the pore size of the gel.

Attachment and culture. Security in the United States and Japan

Attachment theorists maintain that cultural differences are relatively minor, and they focus on universals. Here the authors highlight evidence of cultural variations and note ways in which attachment theory is laden with Western values and meaning. Comparisons of the United States and Japan highlight the cultural relativity of 3 core hypotheses of attachment theory: that caregiver sensitivity leads to secure attachment, that secure attachment leads to later social competence, and that children who are securely attached use the primary caregiver as a secure base for exploring the external world. Attachment theorists use measures of sensitivity, competence, and secure base that are biased toward Western ways of thinking: The measures emphasize the child's autonomy, individuation, and exploration. In Japan, sensitivity, competence, and secure base are viewed very differently, calling into question the universality of fundamental tenets of attachment theory. The authors call for an indigenous approach to the psychology of attachment.

Bladder involvement in systemic sclerosis: urodynamic and histological evaluation in 23 patients

Lower tract involvement of systemic sclerosis is an uncommon manifestation. In this study we have evaluated the functional and morphologic vesical changes in 23 female patients with systemic sclerosis to investigate if bladder dysfunction was correlated with an extended skin sclerosis and/or a more serious organ involvement. Urodynamic alterations were observed in only 3 cases. Urinary symptoms and urodynamic features were correlated neither with severity of vesical fibrosis nor with visceral involvement. Autonomic dysfunction was detected in 13 patients.

Attachment and culture. Security in the United States and Japan

Attachment theorists maintain that cultural differences are relatively minor, and they focus on universals. Here the authors highlight evidence of cultural variations and note ways in which attachment theory is laden with Western values and meaning. Comparisons of the United States and Japan highlight the cultural relativity of 3 core hypotheses of attachment theory: that caregiver sensitivity leads to secure attachment, that secure attachment leads to later social competence, and that children who are securely attached use the primary caregiver as a secure base for exploring the external world. Attachment theorists use measures of sensitivity, competence, and secure base that are biased toward Western ways of thinking: The measures emphasize the child's autonomy, individuation, and exploration. In Japan, sensitivity, competence, and secure base are viewed very differently, calling into question the universality of fundamental tenets of attachment theory. The authors call for an indigenous approach to the psychology of attachment.

Immigrant-Chinese and Euro-American parents' physical closeness with young children: themes of family relatedness

This study examined cultural differences in the expression and meaning of physical closeness. Findings indicated that immigrant-Chinese parents, as compared with Euro-American parents, sleep in closer proximity with their children; more often view independence as children growing with the family; are more likely to emphasize the family unit; and place greater importance on inhibition of expression, adherence to correct values, and hierarchy of relations. Euro-Americans, by contrast, are more accepting of nudity; place more emphasis on psychological benefits of physical closeness and on the child's expression of wants and feelings; more often view independence as celebrating the child's distinctiveness; and place greater importance on intimacy, pleasure, and spousal exclusiveness. The authors suggest that closeness is characterized by an overarching theme of harmony in immigrant-Chinese families and by an overarching theme of romance in Euro-American families.

Psychosocial factors and male seminal parameters

The relationships between (a) alexithymia, (b) extroversion (E), neuroticism (N), psychoticism (P), (c) coping style towards stressors, and seminal parameters, were assessed in 132 males on their first seminal fluid examination by means of a multivariate approach. They were given the TAS-20, the EPQ, and the Coping Inventory for Stressful Situations (CISS). Seminal parameters were: (1) sperm concentration; (2) total sperm count; (3) forward motility; (4) atypical forms. Multiple regressions considering quantitative parameters of seminal status as criterion showed a negative relationship with P, difficulty describing feelings (DDF), while a positive relationship was found for N, and emotion-oriented coping. A discriminant analysis also showed that P, N and DDF distinguished between two groups of normozoospermic and oligozoospermic subjects with a high probability of correct classifications. Results confirm the hypothesis that biological and psychological variables are not completely independent or randomly related in people with an impaired seminal status, although the correlations between psychosocial and biological data are not very strong.

Microheterogeneity of serogroup A (subgroup III) Neisseria meningitidis during an outbreak in northern Ghana

During a meningitis outbreak in the eastern subdistrict of the Kassena-Nankana District of the Upper East Region of Ghana, we analysed cerebrospinal fluid from suspected meningitis cases for the most common causative organisms. In 50 of 92 samples analysed, serogroup A Neisseria meningitidis were detected. The ages of serogroup A N. meningitidis patients ranged from 4 months to 64 years. The case fatality ratio was 20%. Coma or stupor on presentation worsened the prognosis. All serogroup A N. meningitidis isolates recovered revealed the A: 4: P1.9, 20 phenotype characteristic for the subgroup III clonal grouping. No evidence for resistance to penicillin G, chloramphenicol, cefotaxime, ciprofloxacin, rifampicin or tetracycline was found. All strains were resistant to sulphadiazine. Restriction analysis patterns of opa, iga and ingA genes were characteristic for the majority of N. meningitidis serogroup A subgroup III bacteria isolated in Africa after the 1987 epidemic in Mecca. Differences in pulsed-field gel electrophoresis patterns of NheI and SpeI digested DNA revealed microheterogeneity among the Ghanaian isolates.

Complete DNA sequence of a serogroup A strain of Neisseria meningitidis Z2491

Neisseria meningitidis causes bacterial meningitis and is therefore responsible for considerable morbidity and mortality in both the developed and the developing world. Meningococci are opportunistic pathogens that colonize the nasopharynges and oropharynges of asymptomatic carriers. For reasons that are still mostly unknown, they occasionally gain access to the blood, and subsequently to the cerebrospinal fluid, to cause septicaemia and meningitis. N. meningitidis strains are divided into a number of serogroups on the basis of the immunochemistry of their capsular polysaccharides; serogroup A strains are responsible for major epidemics and pandemics of meningococcal disease, and therefore most of the morbidity and mortality associated with this disease. Here we have determined the complete genome sequence of a serogroup A strain of Neisseria meningitidis, Z2491. The sequence is 2,184,406 base pairs in length, with an overall G+C content of 51.8%, and contains 2,121 predicted coding sequences. The most notable feature of the genome is the presence of many hundreds of repetitive elements, ranging from short repeats, positioned either singly or in large multiple arrays, to insertion sequences and gene duplications of one kilobase or more. Many of these repeats appear to be involved in genome fluidity and antigenic variation in this important human pathogen.

Yersinia pestis, the cause of plague, is a recently emerged clone of Yersinia pseudotuberculosis

Plague, one of the most devastating diseases of human history, is caused by Yersinia pestis. In this study, we analyzed the population genetic structure of Y. pestis and the two other pathogenic Yersinia species, Y. pseudotuberculosis and Y. enterocolitica. Fragments of five housekeeping genes and a gene involved in the synthesis of lipopolysaccharide were sequenced from 36 strains representing the global diversity of Y. pestis and from 12-13 strains from each of the other species. No sequence diversity was found in any Y. pestis gene, and these alleles were identical or nearly identical to alleles from Y. pseudotuberculosis. Thus, Y. pestis is a clone that evolved from Y. pseudotuberculosis 1,500-20,000 years ago, shortly before the first known pandemics of human plague. Three biovars (Antiqua, Medievalis, and Orientalis) have been distinguished by microbiologists within the Y. pestis clone. These biovars form distinct branches of a phylogenetic tree based on restriction fragment length polymorphisms of the locations of the IS100 insertion element. These data are consistent with previous inferences that Antiqua caused a plague pandemic in the sixth century, Medievalis caused the Black Death and subsequent epidemics during the second pandemic wave, and Orientalis caused the current plague pandemic.

Shade avoidance responses are mediated by the ATHB-2 HD-zip protein, a negative regulator of gene expression

The ATHB-2 gene encoding an homeodomain-leucine zipper protein is rapidly and strongly induced by changes in the ratio of red to far-red light which naturally occur during the daytime under the canopy and induce in many plants the shade avoidance response. Here, we show that elevated ATHB-2 levels inhibit cotyledon expansion by restricting cell elongation in the cotyledon-length and -width direction. We also show that elevated ATHB-2 levels enhance longitudinal cell expansion in the hypocotyl. Interestingly, we found that ATHB-2-induced, as well as shade-induced, elongation of the hypocotyl is dependent on the auxin transport system. In the root and hypocotyl, elevated ATHB-2 levels also inhibit specific cell proliferation such as secondary growth of the vascular system and lateral root formation. Consistent with the key role of auxin in these processes, we found that auxin is able to rescue the ATHB-2 lateral root phenotype. We also show that reduced levels of ATHB-2 result in reciprocal phenotypes. Moreover, we demonstrate that ATHB-2 functions as a negative regulator of gene expression in a transient assay. Remarkably, the expression in transgenic plants of a derivative of ATHB-2 with the same DNA binding specificity but opposite regulatory properties results in a shift in the orientation of hypocotyl cell expansion toward radial expansion, and in an increase in hypocotyl secondary cell proliferation. A model of ATHB-2 function in the regulation of shade-induced growth responses is proposed.

The opcA and (psi)opcB regions in Neisseria: genes, pseudogenes, deletions, insertion elements and DNA islands

Previous data have indicated that the opc gene encoding an immunogenic invasin is specific to Neisseria meningitidis (Nm) and is lacking in Neisseria gonorrhoeae (Ng). The data presented here show that Nm and Ng both contain two paralogous opc-like genes, opcA, corresponding to the former opc gene, and (psi)opcB, a pseudogene. The predicted OpcA and OpcB proteins possess transmembrane regions with conserved non-polar faces but differ extensively in four of the five surface-exposed loops. Gonococcal OpcA was expressed weakly under in vitro conditions, and it is unknown whether these bacteria can express this protein at high levels. Analysis of the sequences flanking opcA and (psi)opcB revealed a framework of conserved housekeeping genes interspersed with DNA islands. These regions also contained several pseudogenes, deletions and IS elements, attesting to considerable genome plasticity. Both opcA and (psi)opcB are located on DNA islands that have probably been imported from unrelated bacteria. A third island encodes the dcmD/dcrD R/M genes in Ng versus a small open reading frame in most strains of Nm. Rare strains of Nm were identified in which the R/M island has been imported. DNA islands in Nm and Ng seem to have been acquired by recombination via conserved flanking housekeeping genes rather than by insertion of mobile genetic elements.