Characterization of CK2 holoenzyme variants with regard to crystallization

A search for strategies was conducted in order to obtain a human protein kinase CK2 preparation which would be suitable for crystallization, despite the fact that the recombinant enzyme is abundant and can be readily purified to homogeneity. This seemingly contradiction is based on the fact that the catalytic subunit moiety of the human CK2 holoenzyme is not stable neither as a free subunit nor in the tetrameric complex. All attempts to prevent degradation failed. Hence, alternative approaches were designed in order to avoid this degradation, which was expected to hamper any crystallization efforts severely. One of the approaches chosen was the production of a chimeric holoenzyme made up from a human regulatory subunit and a catalytic subunit from Z. mays. The plant catalytic subunit, in contrast to the human counterpart is very stable and does not undergo this kind of degradation. The second strategy to tackle the problem of instability was to produce the homologous recombinant human CK2 holoenzyme and then, instead of trying to avoid degradation, attempt to accelerate degradation until all catalytic subunit material was converted to the degraded form, i.e. a 40 kDa polypeptide.

Characterization of basal nitric oxide production in living cells

Nitric oxide (NO) is an important modulator of immune, endocrine and neuronal functions; however, measuring physiological levels of NO in cell cultures is generally difficult because of the lack of suitable methodologies. We have selected three cell lines from different origins: the neuroblastoma-derived Neuro2A (N2A), the cholinergic SN56 and the non-neuronal COS-1. We first demonstrated the presence of NADPH-diaphoretic activity, a potential marker of the NO-synthesizing (NOS) enzyme. By immunocytochemistry, using specific antibodies for each NOS subtype, we observed that subtype I was present in all cell lines and that subtype II was present in COS-1 and N2A cell lines. The presence of these NOS subtypes was further verified by Western blot analysis. Control cells treated with DAF-2 DA exhibited significant fluorescent levels corresponding to basal NO production. The subcellular distribution of the synthesizing enzyme was consistent with the NO-fluorescence signal; whereas, fixation affected the subcellular pattern of NO fluorescence signal. Addition of NOS inhibitors or NO scavengers to the incubation medium reduced the intensity of the NO fluorescence signal in a concentration-dependent manner. Conversely, increasing concentrations of a NO donor, or incident light, increased the fluorescence intensity. Our observation of NO production and distribution using the DAF-2 method has a direct impact on studies using these cell lines.

Ribavirin induces error-prone replication of GB virus B in primary tamarin hepatocytes

GB virus B (GBV-B) is the closest relative of hepatitis C virus (HCV) and is an attractive surrogate model for HCV antiviral studies. GBV-B induces an acute, resolving hepatitis in tamarins. Utilizing primary cultures of tamarin hepatocytes, we have previously developed a tissue culture system that exhibits high levels of GBV-B replication. In this report, we have extended the utility of this system for testing antiviral compounds. Treatment with human interferon provided only a marginal antiviral effect, while poly(I-C) yielded >3 and 4 log units of reduction of cell-associated and secreted viral RNA, respectively. Interestingly, treatment of GBV-B-infected hepatocytes with ribavirin resulted in an approximately 4-log decrease in viral RNA levels. Guanosine blocked the antiviral effect of ribavirin, suggesting that inhibition of IMP dehydrogenase (IMPDH) and reduction of intracellular GTP levels were essential for the antiviral effect. However, mycophenolic acid, another IMPDH inhibitor, had no antiviral effect. Virions harvested from ribavirin-treated cultures exhibited a dramatically reduced specific infectivity. These data suggest that incorporation of ribavirin triphosphate induces error-prone replication with concomitant reduction in infectivity and that reduction of GTP pools may be required for incorporation of ribavirin triphosphate. In contrast to the in vitro studies, no significant reduction in viremia was observed in vivo following treatment of tamarins with ribavirin during acute infection with GBV-B. These findings are consistent with the observation that ribavirin monotherapy for HCV infection decreases liver disease without a significant reduction in viremia. Our data suggest that nucleoside analogues that induce error-prone replication could be an attractive approach for the treatment of HCV infection if administered at sufficient levels to result in efficient incorporation by the viral polymerase.

Protective immune response to hepatitis C virus in chimpanzees rechallenged following clearance of primary infection

Hepatitis C virus (HCV) infections were evaluated in chimpanzees that had previously cleared HCV and were rechallenged. Animals that had previously cleared HCV infection rapidly cleared homologous and heterologous virus upon rechallenge, indicative of a strong protective immunity. In one animal, sterilizing immunity was observed with regard to viremia, although viral RNA was transiently detected in the liver. Accelerated viral clearance following rechallenge with HCV was observed in animals that had not been exposed to HCV for over 16 years, suggesting that long-lasting protective immunity may be possible. The ability of peripheral blood mononuclear cells (PBMC) to recognize HCV proteins was evaluated during the course of the rechallenge experiments. A very early and strong in vitro recall response to HCV nonstructural proteins appeared to be associated with viral clearance. In contrast, proliferative responses to HCV proteins were not observed in 4 persistently infected chimpanzees, and a weak proliferative response was observed in 1 of 2 animals during acute resolving infection. The results suggest that a strong T-cell proliferative response is induced upon rechallenge of chimpanzees with HCV and that this response is associated with rapid viral clearance. The antibody response to HCV proteins increased by over 1,000-fold in all animals following rechallenge as well. A more complete understanding of the role of the cellular immune response in the clearance of HCV and the nature of the protective immune response following viral clearance may aid in the generation of therapies and vaccines.

Phosphorylation of the Fas associated factor FAF1 by protein kinase CK2 and identification of serines 289 and 291 as the in vitro phosphorylation sites

We previously identified the human Fas associated factor (FAF1) as one of the interacting partners of protein kinase CK2 beta subunit. Since FAF1 is a phosphoprotein we investigated whether it is a substrate for CK2. Here, we report the full length human FAF1 cDNA sequence, expression of FAF1 in Escherichia coli and purification and characterization of FAF1 as a substrate for CK2. FAF1 as well as an N-terminal 40 kDa degradation product serve as substrates for both the recombinant CK2 holoenzyme (km 100 microM) and the isolated catalytic alpha subunit (km 200 microM). Despite the high k(m) values, we obtained evidence that CK2 is the major cellular kinase responsible for FAF1 phosphorylation, using tissue extracts as kinase sources. By MALDI-MS we identified the two serine residues at positions 289 and 291 as the major in vitro CK2 phosphorylation sites. These data may help us elucidate the functions of FAF1 and the involvement of CK2 mediated phosphorylation in processes such as apoptotic signaling, ubiquitination, nuclear translocation and embryonic development.

Multidrug resistance is mediated by large plasmids carrying a class 1 integron in the emergent Salmonella enterica serotype [4,5,12:i:-]

A multidrug-resistant Salmonella enterica serotype [4,5,12:i:-] clone carried a class 1 integron harboring dfrA12 and aadA2 gene cassettes and bla(TEM-1), aac(3)-IV, cmlA1, and tetA genes located in large plasmids of about 140 kb (carrying spv) or 120 kb (lacking spv). Several segregants, lacking multidrug resistance, contained a plasmid smaller than the parental one and no longer hybridized with probes for the lost resistances. The genes mediating resistance to ampicillin, chloramphenicol, and tetracycline in the [4,5,12:i:-] clone are different from those found in the pentadrug-resistant serotype Typhimurium DT104 clone.

Estrogen modulates norepinephrine-induced accumulation of adenosine cyclic monophosphate in a subpopulation of immortalized luteinizing hormone-releasing hormone secreting neurons from the mouse hypothalamus

A subpopulation of luteinizing hormone-releasing hormone (LHRH)-producing cells that express the intermediate filament protein vimentin and the neuronal marker neurofilament 145, but not neurofilament 200 nor glial fibrillary acidic protein, has been isolated from GT1-7 cultures. These cells express the mRNA encoding estrogen receptor alpha (ERalpha) and respond to physiological concentrations of 17beta-estradiol (E2) by reducing the accumulation of cyclic adenosine monophosphate induced by norepinephrine, but not that induced by direct activation of adenylate cyclase. These results indicate that the activity of LHRH-producing neurons may be directly modulated by estrogen. In addition, they are suggestive of an estrogen-dependent desensitization of the beta-adrenoceptor in these cells.

Development of a primary tamarin hepatocyte culture system for GB virus-B: a surrogate model for hepatitis C virus

GB virus-B (GBV-B) causes an acute hepatitis in tamarins characterized by increased alanine transaminase levels that quickly return to normal as the virus is cleared. Phylogenetically, GBV-B is the closest relative to hepatitis C virus (HCV), and thus GBV-B infection of tamarins represents a powerful surrogate model system for the study of HCV. In this study, the course of infection of GBV-B in tamarins was followed using a real-time 5' exonuclease (TaqMan) reverse transcription-PCR assay to determine the level of GBV-B in the serum. Peak viremia levels exceeded 10(9) genome equivalents/ml, followed by viral clearance within 14 to 16 weeks. Rechallenge of animals that had cleared infection resulted in viremia that was limited to 1 week, suggestive of a strong protective immune response. A robust tissue culture system for GBV-B was developed using primary cultures of tamarin hepatocytes. Hepatocytes obtained from a GBV-B-infected animal maintained high levels of cell-associated viral RNA and virion secretion for 42 days of culture. In vitro infection of normal hepatocytes resulted in rapid amplification of cell-associated viral RNA and secretion of up to 10(7) genome equivalents/ml of culture supernatant. In addition, infection could be monitored by immunofluorescence staining for GBV-B nonstructural NS3 protein. This model system overcomes many of the current obstacles to HCV research, including low levels of viral replication, lack of a small primate animal model, and lack of a reproducible tissue culture system.

Crystallization and preliminary characterization of crystals of human protein kinase CK2

The heterotetrameric recombinant holoenzyme of human protein kinase CK2 was purified to homogeneity. It degraded spontaneously to a stable and fully active state in which the catalytic subunit was about 5 kDa smaller than the wild type. The degraded enzyme was crystallized using polyethylene glycol 3350 as precipitant. The crystals belong to the hexagonal space group P6(3). They have unit-cell parameters a = b = 176.0, c = 93.6 A and diffract X-rays to at least 3.5 A resolution. The calculated crystal packing parameter is V(M) = 3.22 A(3) Da(-1), suggesting that one CK2 tetramer is contained in the asymmetric unit and that the solvent content of the unit cell is 62%.

Usefulness of genetic typing methods to trace epidemiologically Salmonella serotype Ohio

Different genetic typing procedures were applied in an epidemiological study of Salmonella serotype Ohio. Isolates that generated identical DNA fingerprints (HinclI ribotypes, ERIC and RAPD profiles) were clustered into the same lineage, and the addition of data from plasmid, integron and resistance profiles was used to differentiate types. Results led to the determination of the endemic and the emergent epidemic types at specific times, and to ascertain the clinical and epidemiological impact of each type. In the series analysed (47 clinical isolates and 3 non-clinical isolates) 11 lineages and 32 types were found. Two lineages were considered prevalent and endemic, and during an epidemiological alert (Spain, 1998) a re-emergence and spread of organisms mainly from the most frequent lineage had occurred. The combination of H-ribotype with ERIC profile, as primary markers, and resistance profile with plasmid profile, as secondary markers, was shown to be the most useful tool to trace epidemiologically Ohio.

[Influence of serious infections due to Gram-negative bacteria on the hospital economy]

Nosocomial infections due to Gram-negative bacteria are very important since they are associated with high morbidity and high hospital costs. A prospective study of 250 inpatients was carried out, 200 of whom had Gram-negative bacterial infections. Patients were divided into groups of 50 according to the localization of the infection (urinary, surgical wound, respiratory tract and bacteremia), with a control group of 50 patients with similar characteristics but no infection. We calculated the cost for the different groups by multiplying the average length of hospital stay in days by the daily cost of the stay. Significant differences were observed in the average length of stay per patient according to the type of infection and how it was acquired. In terms of cost, nosocomial infection due to Gram-negative bacteria was 1,049,139 pesetas more expensive than community-acquired infection. The cost of the stay for patients with postsurgical infection due to Gram-negative bacteria was 1,108, 252 pesetas more expensive than for the group of control patients. Nosocomial infection due to Gram-negative bacteria is associated with a prolongation in hospital stay of 9 to 28 days, which is the factor that most reflects the cost that can be attributed to nosocomial infection. Consensual and protocolized measures which allow for better clinical management need to be developed.

Molecular characterisation of emergent multiresistant Salmonella enterica serotype [4,5,12:i:-] organisms causing human salmonellosis

Salmonella multidrug-resistant clinical organisms identified as serotype [4,5,12:i:-] were typed using selected genetic procedures and compared with typhimurium organisms collected in the same Spanish region. Results showed a low genetic heterogeneity among [4,5,12:i:-] organisms, which generated identical ribotypes and similar but not identical XbaI PFGE, RAPD, and plasmid profiles. Multidrug resistance could be eliminated by curing and seems to be mediated by 140-kb (spvC+) and 120-kb (spvC-) non-self-transferable plasmids. The [4,5,12:i:-] organisms fall into a single genetic lineage, which emerged in 1997 and presents a different degree of genetic relationship with typhimurium lineages.

[Risk factors and prognostics of urinary infections due to gram-negative bacteria]

Urinary infections due to gram-negative bacteria are important because of their high frequency, morbidity and mortality. In order to evaluate the risk factors and prognostics a group of 50 patients with nosocomial urinary infections were studied prospectively and consecutively and were compared with another group of 50 patients with similar characteristics but no infection. The most isolated bacteria were Escherichia coli (68%), followed by Pseudomonas aeruginosa (20%). Bacteremia was found in 22% of the cases. Risk factors included female gender, medical services, nosocomial acquisition, previous use of manipulation techniques such as vesicular probe, prior urinary infections, and the use of cytostatic drugs in the previous six weeks. Mortality was 4%. The factors significantly associated with a poor prognosis were the following: severe underlying disease, a clinically critical situation, previous surgery, complications, type of gram-negative bacteria, use of third generation cephalosporins and ciprofloxacin in the previous six weeks and older age. The mortality of the control group was 8%.

[Risk factors and prognostics of nosocomial infectionof surgical wounds in a general hospital]

Surgical infections due to gram-negative bacteria are important because of their high frequency, morbidity and mortality. In order to evaluate the risk factors and prognostics of gram-negative surgical wound infections a group of 50 patients with surgical infections were studied prospectively and consecutively and were compared with another group of 50 patients with similar characteristics but no infection. No significant differences were observed with respect to age between the two groups. Previous surgery, prior surgical infections and use of wide-spectrum antibiotics in the six weeks before the study were significantly associated with the development of surgical wound infections due to gram-negative bacteria. The most isolated bacteria were Pseudomonas aeruginosa (34%), followed by polymicrobial flora (16%). The factors significantly associated with a poor prognosis were the following: severe underlying disease, a clinically critical situation, previous surgery, arterial hypertension, complications, type of gram-negative bacteria, prior use of wide-spectrum antibiotics in the previous six weeks and older age. No deaths occurred.

Prenatal diagnosis of symptomatic congenital cytomegalovirus infection

OBJECTIVE

The aim of this study was to evaluate whether the amniotic viral load of mothers with primary cytomegalovirus infection correlate with fetal or neonatal outcomes.

STUDY DESIGN

Sixty-eight of 138 pregnant women with primary infection defined by immunoglobulin G seroconversion or the presence of immunoglobulin M with low immunoglobulin G avidity accepted amniocentesis. Polymerase chain reaction and quantitative polymerase chain reaction were used to detect amniotic fluid cytomegalovirus. Cytomegalovirus infection in neonates was determined by means of urinary viral isolation during the first week after birth or the histologic examination of tissue from aborted fetuses.

RESULTS

Cytomegalovirus infection was found in 16 fetuses and neonates (23%), 5 of whom had symptoms. Quantitative polymerase chain reaction showed that the presence of >/=10(3) genome equivalents predicted mother-child infection with 100% probability; >/=10(5) genome equivalents predicted the development of a symptomatic infection.

CONCLUSION

Fewer than expected cytomegalovirus-infected fetuses are at risk for development of cytomegaloviral disease, and this fact may be useful in counseling pregnant women with primary cytomegalovirus infection.

Antimicrobial resistance and spread of class 1 integrons among Salmonella serotypes

The resistance profiles, for 15 antimicrobial agents, of 333 Salmonella strains representing the most frequent nontyphoidal serotypes, isolated between 1989 and 1998 in a Spanish region, and 9 reference strains were analyzed. All strains were susceptible to amikacin, ceftazidime, ciprofloxacin, and imipenem, and 31% were susceptible to all antimicrobials tested. The most frequent types of resistance were to sulfadiazine, tetracycline, streptomycin, spectinomycin, ampicillin, and chloramphenicol (ranging from 46 to 22%); 13% were resistant to these six drugs. This multidrug resistance pattern was found alone or together with other resistance types within serotypes Typhimurium (45%), Panama (23%), and Virchow (4%). Each isolate was also screened for the presence of class 1 integrons and selected resistance genes therein; seven variable regions which carried one (aadA1a, aadA2, or pse-1) or two (dfrA14-aadA1a, dfrA1-aadA1a, oxa1-aadA1a, or sat1-aadA1a) resistance genes were found in integrons.

The changing HIV epidemic in Italian pregnant women

OBJECTIVE

To describe changes in the characteristics of HIV-pregnant women in Italy and the impact of strategies for prevention of HIV vertical transmission.

STUDY DESIGN

Since 1985, HIV-infected women and their children are followed in 23 European centres in the European Collaborative Study (ECS), according to a standard protocol. Eight Italian Obstetric units participating in the ECS enrolled 815 patients.

RESULTS

Overall use of zidovudine to reduce HIV vertical transmission has increased significantly since 1994 and between 1995 and 1997, 57% of Italian women were treated. However, 27% of babies received the infant component of the 076 regimen. Over the years, age at delivery has increased and their CD4 count at delivery decreased, most likely reflecting heterosexually infected women with a longer duration of infection. The increasing rate of elective caesarean section (42%) is not related to maternal, foetal or obstetrical indications, but its use as an intervention to reduce HIV vertical transmission.

CONCLUSIONS

The identification of HIV-infected women during pregnancy or before delivery ensures the appropriate management of the woman and her child, and clinicians should be aware of the increasing number of women with heterosexual acquisition of HIV-infection who may be less easily identified.

Prenatal indicators of congenital cytomegalovirus infection

OBJECTIVE

To assess the validity of a diagnostic protocol designed to predict the outcome of newborns of mothers suspected to have primary cytomegalovirus (CMV) infection during the first 4 months of pregnancy.

STUDY DESIGN

Anti-CMV immunoglobulin (Ig) M detection by enzyme immunoassay and immunoblot together with the determination of anti-CMV IgG avidity allowed us to classify 456 women as (1) uninfected, (2) undergoing either a primary or a recurrent infection, or (3) having an undefined serologic condition. Prenatal diagnosis was carried out at 21 to 23 weeks' gestation for women. The presence of the virus in the amniotic fluid was determined by culture, polymerase chain reaction, and quantitative polymerase chain reaction. Macroscopic and histologic examinations were undertaken on tissue from aborted fetuses, whereas for newborns culture was performed on urine sampled during the first week of life.

RESULTS

Congenital infections were found exclusively among women undergoing a primary infection. The quantitative determination of CMV DNA in the amniotic fluid of at least 10(3) genome equivalents gave a 100% certainty of detecting an infected fetus. Higher viral loads were associated with fetuses or newborns with symptoms.

CONCLUSIONS

IgM tests and the IgG avidity determination can identify all women at risk of transmitting CMV. Furthermore, a high CMV DNA load in amniotic fluid could be an indicator of symptomatic congenital infection at a relatively early stage of pregnancy.

Maternal IgG avidity and IgM detected by blot as diagnostic tools to identify pregnant women at risk of transmitting cytomegalovirus

In this study, we determined the avidity index (AI) of anticytomegalovirus (CMV) immunoglobulin G (IgG) and the anti-CMV immunoglobulin M (IgM) profile in 124 pregnant women, 87 of whom were considered at risk of transmitting CMV infection to their offspring and 37 of whom were at no risk. IgG avidity and blot for IgM were performed on two serum samples from each woman, at 6-18 weeks' gestation and at 20-23 weeks' gestation. Pregnancy outcomes were monitored. The results obtained showed that the determination of anti-CMV IgG avidity at 6-18 weeks' gestation can identify all women who would have an infected fetus/newborn (100% sensitivity), whereas IgM detected by blot had poorer results (69% sensitivity). Interestingly, at 20-23 weeks' gestation, the sensitivity of IgM detection by blot was higher than that obtained by avidity (75 % and 63%, respectively) and the combination of IgG avidity and IgM by blot yielded the best results (81% sensitivity).

Application of PFGE performed with XbaI to an epidemiological and phylogenetic study of Salmonella serotype typhimurium. Relations between genetic types and phage types

PFGE performed with XbaI was evaluated and applied as a typing method in a series of 68 Salmonella serotype Typhimurium strains collected in a Spanish region throughout 1984-1994, and four reference strains. Using bands > 100 kb as a separation criterion, 26 pulsed-field profiles (PFPs) were defined, with a discrimination index of 0.87. The XbaI-profiles were grouped into three clusters and two additional branches in a dendrogram of similarity (significance level = 0.7). Strains belonging to PFP-X1 and PFP-X2 predominated (26.4% and 23.6%, respectively) and fell into the major cluster. The series had been previously analysed by phage typing and a three-way ribotyping procedure, and a certain degree of relation among the three methods was revealed, PFGE being the most discriminatory. Combining data from the three methods a further differentiation into 46 clonal lines was obtained, and four lines, at least, could be considered as endemic in the region under study. This procedure proved to be a powerful epidemiological tool for characterization of Typhimurium and in the investigation of outbreaks.

Protein kinase CK2: evidence for a protein kinase CK2beta subunit fraction, devoid of the catalytic CK2alpha subunit, in mouse brain and testicles

The highest CK2 activity was found in mouse testicles and brain, followed by spleen, liver, lung, kidney and heart. The activity values were directly correlated with the protein expression level of the CK2 subunits alpha (catalytic) and beta (regulatory). The alpha' subunit was only detected in brain and testicles. By contrast, Northern blot analyses of the CK2alpha mRNA revealed a somewhat different picture. Here, the strongest signals were obtained for brain, liver, heart and lung. In kidney, spleen and testicles mRNAs were only weakly detectable. For CK2alpha' mRNA distribution strong signals were observed for lung, liver and testicles. In the case of CK2beta mRNA the highest signals were found for testicles, kidney, brain and liver. The amount of CK2beta mRNA in testicles was estimated to be about 6-fold higher than in brain. The strongest CK2beta signals in the Western blot were found for testicles and brain. The amount of CK2beta protein in brain in comparison to the other organs (except testicles) was estimated to be ca. 2-3-fold higher whereas the ratio of CK2beta between testicles and brain was estimated to be 3-4-fold. Results from the immunoprecipitation experiments support the notion for the existence of free CK2beta population and/or CK2beta in complex with other protein(s) present in brain and testicles. In all other mouse organs investigated, i.e. heart, lung, liver, kidney and spleen, no comparable amount of free CK2beta was observed. This is the first physiological evidence for the existence of a 'free CK2beta' (or in complex with proteins other than CK2a) in normal animal tissue apart from the hitherto dogmatic association with CK2alpha in a tetrameric holoenzyme complex.

GTP plus water mimic ATP in the active site of protein kinase CK2

The structures of the catalytic subunit of protein kinase CK2 from Zea mays complexed with Mg2+ and with analogs of ATP or GTP were determined to 2.2 A resolution. Unlike most other protein kinases, CK2 from various sources shows 'dual-cosubstrate specificity', that is, the ability to efficiently use either ATP or GTP as a cosubstrate. The structures of these complexes demonstrate that water molecules are critical to switch the active site of CK2 from an ATP- to a GTP-compatible state. An understanding of the structural basis of dual-cosubstrate specificity may help in the design of drugs that target CK2 or other kinases with this property.

Potential of three-Way randomly amplified polymorphic DNA analysis as a typing method for twelve Salmonella serotypes

The potential of a three-way randomly amplified polymorphic DNA (RAPD) procedure (RAPD typing) for typing Salmonella enterica strains assigned to 12 serotypes was analyzed. The series of organisms used included 235 strains (326 isolates) collected mainly from clinical samples in the Principality of Asturias and 9 reference strains. RAPD typing was performed directly with broth cultures of bacteria by using three selected primers and optimized PCR conditions. The profiles obtained with the three primers were used to define RAPD types and to evaluate the procedure as a typing method at the species and serotype levels. The typeability was 100%; the reproducibility and in vitro stability could be considered good. The concordance of RAPD typing methods with serotyping methods was 100%, but some profiles obtained with two of the three primers were obtained with strains assigned to different serotypes. The discrimination index (DI) within the series of organisms was 0.94, and the DI within serotypes Typhimurium, Enteritidis, and Virchow were 0.72, 0.52, and 0.66, respectively. Within these serotypes the most common RAPD types were differentiated into phage types and vice versa; combining the types identified by the two procedures (RAPD typing and phage typing) resulted in further discrimination (DI, 0. 96, 0.74, and 0.87, respectively). The efficiency, rapidity, and flexibility of the RAPD typing method support the conclusion that it can be used as a tool for identifying Salmonella organisms and as a typing method that is complementary to serotyping and phage typing methods.

Determination of mRNA, and protein levels of p53, MDM2 and protein kinase CK2 subunits in F9 cells after treatment with the apoptosis-inducing drugs cisplatin and carboplatin

Protein kinase CK2 is a pleiotropic serine/threonine kinase which has been shown to phosphorylate numerous substrates. Evidence is accumulating that CK2 may exist complexed to a variety of cellular proteins, e.g. p53, MDM2, and A-Raf. Here, we explored the effects of the chemotherapeutic drugs cisplatin and carboplatin on the mRNA and protein levels of p53, MDM2 and CK2 in a murine teratocarcinoma cell line F9. Northern and Western blot analyses were performed and the CK2 activity was determined. The degree of apoptosis after drug treatment was assessed using the TUNEL test. Six hours after cisplatin and carboplatin treatment, the RNA level of p53 dropped by 59% +/- 9% and 86% +/- 8% respectively, whereas the observed level of p53 protein rose to 7 and 10 times over the untreated control, respectively. Treatment with 33 microM cisplatin prompted apoptosis as early as 4 h after drug treatment. More than 50% apoptotic cells were seen after 6 h. We conclude that cisplatin and its second generation drug carboplatin act similarly i.e. both drugs cause a concomitant decrease in p53 mRNA and an increase in p53 protein level. After 4 h treatment with either of the two drugs, p53 levels reach a threshold which leads to the initiation of apoptosis.

CK2: a protein kinase in need of control

Protein kinase CK2 is a heterotetrameric alpha2beta2 Ser/Thr protein kinase with some features unusual among the eukaryotic protein kinases: (1) CK2 recognizes phosphoacceptor sites specified by several acidic determinants; (2) CK2 can use both ATP and GTP as phosphoryl donors; and (3) the regulatory properties of CK2 are poorly understood; it is insensitive to any known second messenger and displays high basal activity. To gain insight into CK2 regulation and to understand its unusual properties, site-directed mutagenesis experiments on both subunits and X-ray crystallographic studies of the catalytic alpha-subunit were performed. The noncatalytic beta-subunit has at least three functions: (1) it protects the alpha-subunit against denaturing agents or conditions; (2) it alters the substrate specificity of the alpha-subunit; and (3) it modulates the activity of the enzyme, i.e., depending on the substrate, it increases or decreases the activity of the alpha-subunit. Mutagenesis experiments revealed that an acidic stretch between amino acids 55 and 64 has a down-regulatory and autoinhibitory function. Mutational analysis of the alpha-subunit has revealed a network of unique basic residues that are responsible for the recognition of phosphoacceptor substrates and for down-regulation by the beta-subunit and by polyanionic inhibitors. The resolution of the crystal structure of Zea mays CK2 alpha-subunit has disclosed the structural features that are responsible for high basal activity and for unusual response to nucleotide analogs. The increasing knowledge of CK2 structure-function relationships will allow the design of highly selective inhibitors of this pleiotropic kinase with oncogenic potential.

Generation of transmissible hepatitis C virions from a molecular clone in chimpanzees

Multiple alignments of hepatitis C virus (HCV) polyproteins from six different genotypes identified a total of 22 nonconsensus mutations in a clone derived from the Hutchinson (H77) isolate. These mutations, collectively, may have contributed to the failure in generating a "functionally correct" or "infectious" clone in earlier attempts. A consensus clone was constructed after systematic repair of these mutations, which yielded infectious virions in a chimpanzee after direct intrahepatic inoculation of in vitro transcribed RNAs. This RNA-infected chimpanzee has developed hepatitis and remained HCV positive for more than 11 months. To further verify this RNA-derived infectivity, a second naive chimpanzee was injected intravenously with serum collected from the first chimpanzee. Infectivity analysis of the second chimpanzee demonstrated that the HCV infection was successfully transmitted, which validated unequivocally the infectivity of our repaired molecular clone. Amino acid sequence comparisons revealed that our repaired infectious clone had 4 mismatches with the isogenic clone reported by Kolykhalov et al. (1997, Science 277, 570-574) and 8 mismatches with that reported by Yanagi et al. (1997, Proc. Natl. Acad. Sci. USA 94, 8738-8743). At the RNA level, more mismatches (43 and 67, respectively) were identified; most of them were synonymous substitutions. Further comparisons with 16 isolates from different genotypes demonstrated that our repaired clone shares greater consensus than the reported isogenic clones. This approach of generating infectious HCV RNA validates the importance of amino acid sequence consensus in relation to the biology of HCV.

Presecretory degradation of apolipoprotein [a] is mediated by the proteasome pathway

Plasma levels of atherogenic lipoprotein [a] (Lp[a]) vary over a 1000-fold range and are largely determined by the gene for its unique glycoprotein, apolipoprotein [a] (apo[a]). The apo[a] locus comprises more than 100 alleles, encoding proteins from <300 to >800 kDa. Using primary baboon hepatocyte cultures, we previously demonstrated that differences in the secretion efficiency of apo[a] allelic variants contribute to the variation in plasma Lp[a] levels. In the current study, we investigated the mechanism of apo[a] presecretory degradation. The proteasome inhibitors, acetyl-leucyl-leucyl-norleucinal and lactacystin, prevented apo[a] degradation and increased apo[a] secretion. Transfection with an HA-tagged ubiquitin construct demonstrated the accumulation of ubiquitinated apo[a] in the presence of lactacystin. These results suggest a role for the cytoplasmic proteasome in apo[a] proteolysis. Apo[a] that accumulated intracellularly in the presence of lactacystin remained sensitive to endo-B-N-glucosaminidase H, and apo[a] degradation was reversibly inhibited by brefeldin A, suggesting that transport to a post-endoplasmic reticulum (ER) pre-medial Golgi compartment is required for apo[a] degradation. Newly synthesized apo[a] bound to the ER chaperone calnexin and conditions that enhanced this interaction prevented apo[a] degradation, suggesting that calnexin can protect apo[a] from proteolysis. These studies provide further support for the role of the proteasome in endoplasmic reticulum quality control, and expand this role to one that influences plasma levels of the atherogenic lipoprotein Lp[a].-White, A. L., B. Guerra, J. Wang, and R. E. Lanford. Presecretory degradation of apolipoprotein[a] is mediated by the proteasome pathway.

Protein kinase CK2 and its role in cellular proliferation, development and pathology

Protein kinase CK2 is a pleiotropic, ubiquitous and constitutively active protein kinase that can use both ATP and GTP as phosphoryl donors with specificity for serine/threonine residues in the vicinity of acidic amino acids. Recent results show that the enzyme is involved in transcription, signaling, proliferation and in various steps of development. The tetrameric holoenzyme (alpha2beta2) consists of two catalytic alpha-subunits and two regulatory beta-subunits. The structure of the catalytic subunit with the fixed positioning of the activation segment in the active conformation through its own aminoterminal region suggests a regulation at the transcriptional level making a regulation by second messengers unlikely. The high conservation of the catalytic subunit from yeast to man and its role in the tetrameric complex supports this notion. The regulatory beta-subunit has been far less conserved throughout evolution. Furthermore the existence of different CK2beta-related proteins together with the observation of deregulated CK2beta levels in tumor cells and the reported association of CK2beta protein with key proteins in signal transduction, e.g. A-Raf, Mos, pg90rsk etc. are suggestive for an additional physiological role of CK2beta protein beside being the regulatory compound in the tetrameric holoenzyme.

Anticytomegalovirus (anti-CMV) immunoglobulin G avidity in identification of pregnant women at risk of transmitting congenital CMV infection

In this work, we show that the determination of the anticytomegalovirus antibody avidity carried out before week 18 of gestation is a helpful tool to identify women for enrollment in prenatal diagnosis. This procedure can identify all pregnant women who will give birth to an infected newborn.

Prenatal diagnosis of congenital cytomegalovirus infection

We report here the results of a study on the prenatal diagnosis of congenital cytomegalovirus (CMV) infection. The study was carried out by both PCR and virus isolation from amniotic fluid (AF) for 82 pregnant women at risk of transmitting CMV for the detection of (i) seroconversion to CMV immunoglobulin G (IgG) positivity during the first trimester of pregnancy, (ii) symptomatic CMV infection in the mother during the first trimester of pregnancy or intrauterine growth retardation detected by ultrasound or abnormal ultrasonographic findings suggestive of fetal infections, and (iii) seropositivity for CMV-specific IgM. For 50 women, fetal blood (FB) was also obtained and tests for antigenemia and PCR were performed. The results indicate that AF is better than FB for the prenatal diagnosis of CMV infection. PCR with AF has a sensitivity (SNS) of 100%, a specificity (SPE) of 83.3%, a positive predictive value (PPV) of 40%, and a negative predictive value (NPV) of 100%; rapid virus isolation with the same material has an SNS of 50%, an SPE of 100%, a PPV of 100%, and an NPV of 94.7%. Fewer than 10% of the women positive for IgM by enzyme immunoassay (EIA) had a congenitally infected fetus or newborn infant. When EIA IgM positivity was confirmed by Western blotting (WB) and the WB profile was considered, the percent transmission detected among women with an "at-risk" profile was higher than that observed among IgM-positive women and was the same as that among women who seroconverted during the first trimester of pregnancy (transmission rates of 29 and 25%, respectively).

p53 and the ribosomal protein L5 participate in high molecular mass complex formation with protein kinase CK2 in murine teratocarcinoma cell line F9 after serum stimulation and cisplatin treatment

Using the murine teratocarcinoma cell line F9 we investigated the influence of serum stimulation and cisplatin treatment on the p53, CK2, MDM2 levels. Both treatments led to an increase of p53, though with different kinetics; the other proteins investigated were not affected. We present direct evidence by immunoprecipitation for an association of protein kinase CK2 holoenzyme (alpha2beta2), p53, and the ribosomal protein L5. The results suggest complexes between the CK2 holoenzyme and p53 but also p53/CKbeta complexes. Furthermore we provide evidence for the existence of high molecular mass complexes of CK2 in vivo. This is the first evidence that, under physiological conditions, protein kinase CK2 does not exist solely as a heterotetramer, but predominantly in association with other proteins.

Combined cytology and colposcopy to screen for cervical cancer in pregnancy

OBJECTIVE

To evaluate the accuracy of cytologic screening in pregnancy through routine colposcopy and to confirm the safety of conservative management of cervical intraepithelial neoplasia (CIN) in pregnancy.

STUDY DESIGN

In total, 3,658 pregnant women, screened for cervical cancer with either cytology or colposcopy, were prospectively evaluated. Patients with abnormal findings underwent colposcopically directed biopsy and, in case of CIN, repeat cytology and colposcopy. Biopsy was repeated in case of suspected progression of the lesion. Suspected microinvasion was the only reason for diagnostic conization during pregnancy. After delivery, excisional treatment provided a final specimen from all patients. Diagnostic methods were compared.

RESULTS

Comparison between cytology and colposcopy showed 97.1% concordance with a few false positives (2.5%) and false negatives (0.2%). Abnormal cytology and colposcopy, as compared with histology, showed similar concordances, but the risk of underestimation by cytology was significantly higher (P < .05). Initial and final histology of the 63 cases of CIN and microinvasive carcinoma showed 88.9% concordance. Progression of the lesion was not observed.

CONCLUSION

These data do not justify combined use of cytology and colposcopy to improve screening for cervical cancer in pregnancy. Delayed treatment of CIN after delivery is safe.

Intra-uterine parvovirus B19 infection and meconium peritonitis

B19 fetal infection has been associated with hydrops or fetal death. We report four cases of meconium peritonitis in hydropic fetuses with laboratory diagnosis of B19 infection. Parvovirus B19 DNA was detected by in situ hybridization both in cord blood and in amniotic cells in three fetuses, while in one case only cord blood was available and proved positive. Signs of active or recent B19 infection in maternal serum samples were documented only in two cases, which proved positive for specific IgM antibodies anti-B19. Maternal B19 infections were asymptomatic and fetal anomalies were observed during a routine ultrasound scan. A common feature of the hydropic fetuses was the presence of abdominal ascites concomitant with or preceding alterations, suggesting meconium peritonitis. The four pregnancies had a preterm outcome: in two cases infants recovered following surgical treatment, in one case spontaneously, and the other one was stillborn. Since vascular inflammation has been documented in B19 infection and congenital bowel obstruction results from vascular damage during fetal life, our observation suggests the need for investigating B19 infection in the presence of meconium peritonitis for a better understanding of the pathogenetic potential of B19 parvovirus in intra-uterine infection.

Crystal structure of the catalytic subunit of protein kinase CK2 from Zea mays at 2.1 A resolution

CK2alpha is the catalytic subunit of protein kinase CK2, an acidophilic and constitutively active eukaryotic Ser/Thr kinase involved in cell proliferation. A crystal structure, at 2.1 A resolution, of recombinant maize CK2alpha (rmCK2alpha) in the presence of ATP and Mg2+, shows the enzyme in an active conformation stabilized by interactions of the N-terminal region with the activation segment and with a cluster of basic residues known as the substrate recognition site. The close interaction between the N-terminal region and the activation segment is unique among known protein kinase structures and probably contributes to the constitutively active nature of CK2. The active centre is occupied by a partially disordered ATP molecule with the adenine base attached to a novel binding site of low specificity. This finding explains the observation that CK2, unlike other protein kinases, can use both ATP and GTP as phosphorylating agents.

Pidotimod in the management of vulvar papillomatosis: double-blind clinical trial versus placebo

To investigate whether the immune system improvement induced by pidotimod increases the rate of spontaneous disappearance of vulvar papillomatous lesions, a multicenter, double-blind, placebo-controlled, randomized clinical trial was performed. Forty-nine patients (23 in the pidotimod group and 26 in the placebo group) with first diagnosis of vulvar papillomatosis as shown by clinical and histological findings underwent 90-day treatment with oral 800-mg pidotimod once a day or identical placebo. The main outcome measure was the difference between vulvar papillomatous infected area before and after treatment judged by the following: complete regression (complete disappearance of all papillomatous lesions); partial regression (a decrease of at least 75% of the infected area); no response (a decrease of less than 75% of the infected area or new viral lesions not present at baseline). Forty patients completed the trial according to the study protocol and were entered in the "per protocol" analysis of efficacy. Complete regression was observed in 12 of 18 patients (66.7%) receiving pidotimod compared with 7 of 22 patients (31.8%) receiving placebo. The total infected surface area at the end of treatment was 10.1 +/- 18.5 mm2 (mean +/- SD) in the pidotimod arm and 198.3 +/- 399.2 mm2 in the placebo arm (p < 0.05 between treatment). Notwithstanding the fact that better results were obtained in the pidotimod group, more data are needed to confirm our encouraging results.

Expression, purification and crystallization of the catalytic subunit of protein kinase CK2 from Zea mays

The catalytic (alpha) subunit of protein kinase CK2 (CK2alpha) was originally cloned and overexpressed in the Escherichia coli strain pT7-7/BL21(DE3). The protein has been purified to homogeneity and crystallized. The crystals belong to the monoclinic space group C2, they have unit-cell parameters a = 142.6, b = 61.3, c = 45.6 A, beta = 103.3 degrees and diffract X-rays to at least 2.0 A resolution. The calculated crystal packing parameter is Vm = 2.47 A3 Da-1 suggesting that one CK2alpha molecule is contained in the asymmetric unit and that the solvent content of the unit cell is 50%.

The carboxy terminus of p53 mimics the polylysine effect of protein kinase CK2-catalyzed MDM2 phosphorylation

The oncogene product MDM2 can be phosphorylated by protein kinase CK2 in vitro 0.5-1 mol of phosphate were incorporated per mol MDM2 protein. The catalytic subunit of protein kinase CK2 (alpha-subunit) catalyzed the incorporation of twice as much phosphate into the MDM2 protein as it was obtained with the holoenzyme. Polylysine stimulated MDM2 phosphorylation by CK2 holoenzyme threefold in contrast to the alpha-subunit-catalyzed MDM2 phosphorylation which was reduced by about 66% when polylysine was added. Full length p53, but also a peptide representing a C-terminal fragment of the tumor suppressor gene product p53 (amino acids 264-393 which also harbors the CK2beta interaction site at amino acids 287-340) mimicked the polylysine effect in all respects, ie. stimulation of phosphate incorporation by CK2 holoenzyme and inhibition in the presence of the catalytic CK2 alpha-subunit. Stimulation by p53(264-393) was on the average close to twofold and inhibition in the case of the alpha-subunit-catalyzed MDM2 phosphorylation was about 40%. Phosphorylation of MDM2 by CK2 holoenzyme in the presence of the p21(WAF1/CIP1), known to be a potent inhibitor of cyclin-dependent protein kinases, also led to a significant reduction of phosphate incorporation into MDM2 indicating that p21(WAF1/CIP1) does not exclusively inhibit cell cycle kinases. Furthermore, these data add new insight into the autoregulatory loop which include p21(WAF1/CIP1), MDM2 protein, CK2 and p53.

Sequence specificity of C-terminal Src kinase (CSK)--a comparison with Src-related kinases c-Fgr and Lyn

An eicosapeptide encompassing the C-terminal tail of c-Src (Tyr527) which is conserved in most Src-related protein kinases, is phosphorylated by C-terminal Src kinase (CSK) and by the two Src-related protein kinases c-Fgr and Lyn, with similar kinetic constants. Two related peptides reproducing the C-terminal segments of c-Src mutants defective in CSK phosphorylation [MacAuley, A., Okada, M., Nada, S., Nakagawa, H. & Cooper, J. A. (1993) Oncogene 8, 117-124] AFLEDSCTGTEPLYQRGENL (mutant number 28) and AFLEDNFTGTKPQYHPGENL (mutant number 29), proved a better and a much worse substrates, respectively than the wild-type peptide, with either CSK or the two Src kinases. By changing individual residues in the best peptide substrate, it was shown that the main element responsible for its improved phosphorylation is leucine at position -1 (instead of glutamine), while lysine at position -3 (instead of glutamate) has a detrimental effect, possibly accounting for the negligible phosphorylation of peptide derived from mutant number 29. By contrast to most peptide substrates, including the Src C-terminal peptides, which exhibit relatively high K(m) values, a polyoma-virus-middle-T-antigen-(mT)-derived peptide with tyrosine embedded in a highly hydrophobic sequence (EEEPQFEEIPIYLELLP) exhibits with CSK a quite low K(m) value (63 microM). Consistent with this, the optimal sequence selected by CSK in an oriented peptide library is XXXIYMFFF. This is different from sequences selected by Lyn (DEEIYEELX) and c-Fgr (XEEIYGIFF), although they all share a high selection for a hydrophobic residue at n-1. In sharp contrast, TPKIIB/p38syk, related to the catalytic domain of p72syk, selects acidic residues at nearly all positions, n-1 included. These data support the notion that the features determining the specific phosphorylation of the C-terminal tyrosine residue of Src do not reside in the primary structure surrounding the target tyrosine. They also show that this site does not entirely fulfil the optimal consensus sequence recognized by CSK, disclosing the possibility that as yet unrecognized CSK targets structurally unrelated to the C-terminal tyrosine residue of Src kinases may exist.

A three-way ribotyping scheme for Salmonella serotype Typhimurium and its usefulness for phylogenetic and epidemiological purposes

Ribotyping of Salmonella serotype Typhimurium strains was optimised as a tool for epidemiological and phylogenetic purposes. Of five restriction endonucleases evaluated on a series of 84 isolates, HincII, SalI and PvuII were the most useful, generating 13, 9 and 9 ribotypes with 17, 11 and 18 polymorphic restriction sites, and attaining a discrimination index (DI) of 0.81, 0.53 and 0.59, respectively. The combination of results from tests with the three enzymes provided further discrimination (19 ribotypes, DI=0.84). It proved useful for clonal analysis, defining 19 clonal lines with a remarkable degree of genetic heterogeneity, that were grouped into two major clusters (including 12 and 7 lines, respectively) at a significance level of 0.65. When the attributes of this system were compared with those of phage typing, it was found that ribotyping showed higher typability and sensitivity, supporting its use as an appropriate molecular method. In tracing the molecular epidemiology of Typhimurium strains in Asturias, six lines were found that could be considered endemic and were represented by organisms implicated in salmonellosis throughout the period of study; another four lines included organisms isolated from meat, water or both.

Influence of allelic variation on apolipoprotein(a) folding in the endoplasmic reticulum

Plasma levels of lipoprotein(a) (Lp(a)) vary over 1000-fold between individuals and are determined by the gene for its unique apolipoprotein, apo(a), which has greater than 100 alleles. Using primary baboon hepatocyte cultures, we previously demonstrated that differences in the ability of apo(a) allelic variants to escape the endoplasmic reticulum (ER) are a major determinant of Lp(a) production rate. To examine the reason for these differences, the folding of newly synthesized apo(a) was analyzed in pulse-chase experiments. Samples were harvested in the presence of N-ethylmaleimide to preserve disulfide-bonded folding intermediates, and apo(a) was analyzed by immunoprecipitation and SDS-polyacrylamide gel electrophoresis. Apo(a) required a prolonged period (30-60 min) to reach its fully oxidized form. Multiple folding intermediates were resolved, including a disulfide-linked, apo(a)-containing complex. Unexpectedly, all allelic variants examined showed similar patterns and kinetics of folding. Even "null" apo(a) proteins, which are unable to exit the ER, appeared to fold normally. The ER glucosidase inhibitor, castanospermine, prevented apo(a) secretion, but did not inhibit folding. This suggests that an event which is dependent on trimming of N-linked glucoses, and which occurs after the folding events detectable in our assay, is required for apo(a) secretion. Differences in the ability to undergo this event may explain the variable efficiency with which apo(a) allelic variants exit the ER.

The spleen protein-tyrosine kinase TPK-IIB is highly similar to the catalytic domain of p72syk

TPK-IIB is a protein kinase that is predominant in the cytosol of spleen and is characterized by a high specific activity toward acidic peptide substrates and a low auto-phosphorylation activity. A prominent 52-kDa component purifies with the kinase [Marin, O., Donella-Deana, A., Brunati, A. M., Fischer, S. & Pinna, L. A. (1991) J. Biol. Chem. 266, 17798-17803]. Here we demonstrate that the 52-kDa protein displays sequence identity with the Miller-Dieker lissencephaly protein (LIS 1). The protein is not related to any known protein kinase and lacks an ATP-binding motif. The ATP binding and phosphotransferase activities of TPK-IIB can be fully accounted for by a minor 38-kDa protein band (p38/TPK-IIB) which can be separated from the 52-kDa protein by Mono-Q/FPLC in the presence of EDTA. Sequence analysis of p38/TPK-IIB reveals a high level of similarity, if not identity, with the catalytic domain of p72syk, a protein-tyrosine kinase implicated in the activation of hematopoietic cells. Antibodies raised against the catalytic domain of p72syk, but not antibodies raised against its N-terminal segment, cross-react with p38/TPK-IIB. The peptide substrate specificity of p72syk is almost identical to that of p38/TPK-IIB, which also supports the classification of TPK-IIB as a close relative (possibly a proteolytic or alternative spliced form) of p72syk. p38/TPK-IIB, however, exhibits a specific activity which is sixfold higher than that of p72syk and appears to be 50-fold more sensitive to inhibition by heparin. Thus, the observation that Ca(2+)-dependent degradation of p72syk by particulate fraction of rat spleen is accompanied by increased catalytic activity and increased sensitivity to heparin would be consistent with the possibility that hyperactive p38/TPK-IIB might be proteolytically generated from p72syk in response to an increase of intracellular Ca2+.

Microcolposcopic topographic endocervical assessment before excisional treatment of cervical intraepithelial neoplasia

OBJECTIVE

To evaluate whether microcolposcopic topographic endocervical assessment reduces the failures of excisional treatment of cervical intraepithelial neoplasia (CIN).

METHODS

Three hundred fifty patients with colposcopic and histopathologic findings of endocervical CIN were recruited for excisional treatment. Three hundred forty-eight of these were randomized to have or not have microcolposcopy before excisional treatment. Measurement of endocervical lesion was the only aim of microcolposcopic evaluation. When an endocervical extension was available, the cone biopsy was cut according to microcolposcopic measurement. Excision status was evaluated and related to presurgical management on operative specimens. After excision, patients were followed-up for at least 5 years after treatment. Three hundred thirty (171 and 159 with and without preoperative microcolposcopy, respectively) patients completed the study. Disease persistences were defined by cytologic, colposcopic, and histologic results. Microcolposcopic value was defined as completeness of excision and/or lack of persistent disease. RESULTS. On surgical specimens, involved margins were detected in 19 (5.4%) cases. Presurgical microcolposcopy was performed in only one of these cases. The difference of incomplete excision between cases with or without microcolposcopy was statistically significant (P < .001). In patients who were followed-up, persistent disease was detected in one (0.6%) woman in the microcolposcopy group and in 16 (10%) women in the control group. Comparison between the two groups showed a significantly lower risk of persistent disease when presurgical microcolposcopy was performed (P < .001).

CONCLUSION

By measuring endocervical extension of the lesion, preoperative microcolposcopy allows individualized cones, thus improving the prognosis after excisional treatment of CIN.

Different susceptibility of protein kinases to staurosporine inhibition. Kinetic studies and molecular bases for the resistance of protein kinase CK2

A systematic analysis reveals that out of 20 protein kinases examined, specific for either Ser/Thr or Tyr, the majority are extremely sensitive to staurosporine, with IC50 values in the low nanomolar range. A few of them however, notably protein kinases CK1 and CK2, mitogen-activated protein (MAP) kinase and protein-tyrosine kinase CSK, are relatively refractory to staurosporine inhibition, exhibiting IC50 values in the micromolar range. With all protein kinases tested, namely PKA, CK1, CK2, MAP kinase (ERK-1), c-Fgr, Lyn, CSK and TPK-IIB/p38Syk, staurosporine inhibition was competitive with respect to ATP, regardless of its inhibitory power. In contrast, either uncompetitive or noncompetitive kinetics of inhibition with respect to the phosphoacceptor substrate were exhibited by Ser/Thr and Tyr-specific protein kinases, respectively, consistent with a different mechanism of catalysis by these two sub-families of kinases. Computer modeling based on PKA crystal structure in conjunction with sequence analysis suggest that the low sensitivity to staurosporine of CK2 may be accounted for by the bulky nature of three residues, Val66, Phe113 and Ile174 which are homologous to PKA Ala70, Met120 and Thr183, respectively. In contrast these PKA residues are either conserved or replaced by smaller ones in protein kinases highly sensitive to staurosporine inhibition. On the other hand, His160 which is homologous to PKA Glu170, appears to be responsible for the unique behaviour of CK2 with respect to a staurosporine derivative (CGP44171A) bearing a negatively charged benzoyl substituent: while CGP44171A is 10- 100-fold less effective than staurosporine against PKA and most of the other protein kinases tested, it is actually more effective than staurosporine for CK2 inhibition, but it looses part of its efficacy if it is tested on a CK2 mutant (H160D) in which His160 has been replaced by Asp. It can be concluded from these data that the catalytic sites of protein kinases are divergent enough as to allow a competitive inhibitor like staurosporine to be fairly selective, a feature that can be enhanced by suitable modifications designed based on the structure of the catalytic site of the kinase.

Presurgical assessment and therapy of microinvasive carcinoma of the cervix

Retrievable pathological specimens and clinical data on 70 patients with microinvasive carcinoma diagnosed on surgical specimens from cone biopsy or hysterectomy (Stage IA) were reviewed and compared to pertinent findings in the literature with the intent of evaluating diagnostic criteria and defining pathological features that may influence the outcome by therapy. Emphasis was given to the preoperative assessment emphasizing that both an accurate colposcopic evaluation and a detailed pathological analysis may reliably point to a conservative therapeutic approach. Increasing depth of stromal invasion was associated with lesion width as well as with endocervical extension, as measured on colposcopy, microcolpohisteroscopy, and histology. Lymph-vascular space involvement was significantly related to depth of invasion. Two patients of 28 with dissected nodes had node metastases as well as lymph-vascular space involvement. Both developed a pelvic recurrence. One had a > 1- to < or = 3-mm invasion depth, the other a > 3- to < or = 5-mm lesion invasion. While advocating a conservative procedure for Stage IA1, we suggest discrimination with regard to Stage IA2 because we believe that lymph-vascular involvement should be meticulously evaluated. In fact, > 1- to < or = 3-mm lesions without lymph-vascular space involvement can be conservatively treated, while for any other lesion falling within the Stage IA2 category a modified radical histerectomy plus pelvic lymphadenectomy should be recommended.

The incidence of complications after caesarean section in 156 HIV-positive women

OBJECTIVE

To investigate the risks of post-operative complications in HIV-positive mothers who undergo a caesarean section (CS) because the delivery cannot be safely accomplished by the vaginal route or to protect the infant from viral infection.

DESIGN

In a multicentre study, we reviewed the incidence and type of post-operative complications in 156 HIV-positive women who underwent a CS. These results were compared with those observed in an equal number of HIV-uninfected women who matched for the indication requiring a caesarean delivery, the stage of labour, the integrity or rupture of membranes, and the use of antibiotic prophylaxis.

SETTING

Seven teaching hospitals providing obstetrical care for mothers infected with HIV.

RESULTS

We found that six HIV-infected mothers suffered a major complication (two cases of pneumonia, one pleural effusion, two severe anaemia and one sepsis) compared with only one HIV-negative woman who required blood transfusion after surgery. Minor complications like post-operative fever, endometritis, wound and urinary tract infections were significantly more frequent in HIV-positive women than controls. Multivariate analysis revealed that in HIV-infected women the only factor associated with a significant increase in the rate of complications was a CD4 lymphocyte count < 200 x 10(6)/l.

CONCLUSIONS

The results of our study indicate that HIV-positive mothers are at an increased risk of post-operative complications when delivered by CS. The risk of post-operative complications is higher in HIV-infected women who are severely immunodepressed.

Hierarchical phosphorylation of a 50-kDa protein by protein tyrosine kinases TPK-IIB and C-Fgr, and its identification as HS1 hematopoietic-lineage cell-specific protein

TPK-IIB is an acidophilic protein tyrosine kinase devoid of autophosphorylation activity and unrelated to the Src family kinases [Marin, O., Donella-Deana, A., Brunati, A.M., Fischer, S. & Pinna, L. A. (1991) J. Biol. Chem. 266, 17798-17803]. Here, we describe the purification to homogeneity of a 50-kDa prominent substrate (p50) of TPK-IIB from rat spleen homogenates. Microsequence analysis of fragments from purified p50 discloses its homology to HS1, a hematopoietic-lineage cell-specific protein implicated in B-cell-antigen receptor-mediated signalling [Yamanashi, Y., Okada, M., Semba, T., Yamori, T., Umemori, H., Tsunasawa, S., Toyoshima, K., Kitamura, D., Watanabe, T. & Yamamoto, T. (1993) Proc. Natl Acad. Sci. USA 90, 3631-3635]. p50 is an excellent substrate for TPK-IIB, exhibiting very favourable kinetic constants (Km = 0.07 microM, kcat = 1.5) and incorporating up to 4 mol P/mol protein. p50 is, however, a weak substrate for the Src-related protein kinases Lyn and c-Fgr. Once phosphorylated by TPK-IIB, however, p50 is converted into a good substrate for c-Fgr and, to a lesser extent, for Lyn. p50 phosphorylated by TPK-IIB associates with c-Fgr and Lyn, as judged by co-immunoprecipitation with anti-Fgr IgG and anti-Lyn IgG, respectively. These data suggest the involvement of TPK-IIB in B-cell-antigen receptor-mediated signalling, and support the idea that phosphorylation by TPK-IIB might be a prerequisite for the recruitment of certain protein substrates by Src-related protein tyrosine kinases.

Mapping the residues of protein kinase CK2 implicated in substrate recognition: mutagenesis of conserved basic residues in the alpha-subunit

Six mutants of protein kinase CK2 alpha subunit in which basic residues have been mutated into alanines were assayed for their capability to phosphorylate the peptide RRRADDSDDDDD. Two mutants (R228A and R278K279R280A) behaved more or less as alpha wild type and one (H160,166A) was nearly inactive, hampering the calculation of kinetic parameters. In contrast 3 mutants (K74-77A, K79R80K83A and R191,195K198A) phosphorylated the peptide with reduced efficiency accounted for by increased Km and decreased Vmax values. By using derivatives of the RRRADDSDDDDD peptide in which individual aspartyl residues were variably replaced by alanine(s) and two peptide substrates derived from I-2 (KYRIREQESSGEEDSDL and RRKDLHDDEEDEEMSETADGE) it was shown that mutations in the 191-198, 74-77 and 79-83 regions were the least detrimental whenever the acidic determinants were lacking at positions +1, +4/+5 and +3, respectively. These data support the conclusion that the basic residues present in the p+1 loop of CK2 alpha specifically recognize the acidic determinant adjacent to the C-terminal side of serine, while the specificity determinants located more down-stream are variably recognized by different residues of the unique basic cluster spanning between Lys74 and Lys83.

[Discrepancy between histopathological diagnosis based on guided biopsy and cone biopsy of the cervix uteri: analysis of 346 cases of laser conization]

The conservative management of cervical intraepithelial neoplasia (CIN) essentially depended on the introduction and improvement of colposcopy. This technique, allowing to locate the lesion, to estimate its extension and to perform multiple punch biopsies, becomes discriminant in therapeutic choice. Whether colposcopy reveals endocervical involvement or abnormal transformation zone (ANTZ) may be only partially explored, excisional conization should be preferred to ablative therapy since the former advantageously can verify histopathologic diagnosis, confirm completely excision of lesion and rule out invasive carcinoma. The literature shows that cases of invasive lesions can be underestimated and therefore inadequately treated by ablative therapy, emphasizing colposcopy and punch biopsy limitations about suspect and diagnosis of microinvasion. We analyzed data concerning preliminary diagnostic investigations and results of 346 CO2 laser excisional conizations performed between 1984 and 1993. Histopathologic diagnosis on punch biopsy, performed in 111 cases of ANTZ1 and in 235 cases of ANTZ2, shows an agreement with cone biopsy in 30.8% of the cases of CIN1, of 40.9% in cases of CIN2 and of 66.3% in cases of CIN3. Whereas the lesion is overestimated in 30.6% of cases, in which it is likely that punch biopsy has removed the epicenter of the lesion or the lesion in toto, we had an underestimation in 15% of cases, particularly in 4 cases of CIN2, in 38 cases of CIN3 and in all microinvasive processes. The rate of invasive lesions previously ignored and detected only by histopathologic diagnosis on cone biopsy is 2.9%. In only one of these cases colposcopy, even if attributing to each of these the higher grading, shows the suspicion of invasion, whereas the detection of invasive processes is missed in every case by punch biopsy.(ABSTRACT TRUNCATED AT 250 WORDS)