[Treatment of vestibular fistulas in older girls]

The vestibular fistula is the anorectal malformation more frequent in females. In this congenital anomaly the anus is located in the vaginal vestibule, having the rectum a common wall with the vagina. With the posterior sagittal approach described by Alberto Peña it changes the treatment of this anorectal malformation, contributing to the possibility of an aesthetic and functional improvement. From 1996 we have operated on 6 girls with ages included between 6 and 22 years (mean of 11 years) that presented a vestibular fistula. Five cases had been operated on in the neonatal period of vestibular fistula carrying out "cut-back", and a case had been operated on for cloaca syndrome. It was carried out in all of them, posterior sagittal approach disecting the rectum, separating it from the vagina and placing it in the sphincter. In a case a colostomy was carried out and in the other five were carried out intestinal cleaning, maintaining absolute diet and postoperative total parenteral nutrition. The evolution has been favorable in all the cases. the functionality of the neo-anus in terms of continence is absolutely normal, presenting an excellent aesthetic aspect. We believe that the posterior sagittal approach is suitable as surgical treatment of the vestibular fistula. The aesthetic improvement and the satisfaction of our patients motivates us to the realization of this technique that also allows us to correct in only one surgical act associated vaginal malformations.

Evidence of saxitoxin derivatives as causative agents in the 1997 mass mortality of monk seals in the Cape Blanc Peninsula

Monk seals in Cape Blanc (Western Sahara coast) suffered a mass mortality during May-July 1997 which was attributed to a morbillivirus. High performance liquid chromatography (HPLC) analysis on tissues of seals killed during the outbreak and on related fauna showed peaks with retention times coincident with those of some saxitoxin derivatives but their identity was not proved. Here we present results of further HPLC analyses that unambiguously prove the identity of these toxins by mass spectrometry (MS), supporting the hypothesis that this mortality of monk seals was caused by biotoxins rather than by a morbillivirus.

[Bronchoscopies in neonatal intensive care units: safety and efficiency]

The aim of our study is to asses the risks and complications in bronchoscopies at Neonatal Intensive Care Units (NICU). Between 1991 and 1999, we performed 142 bronchoscopies at the NICU. The mean age was 1.6 +/- 1.4 months (2 days-6 months) and mean weight was 2.5 +/- 1 kg (530 g-4.7 kg). We analysed the complications, arterial oxygen saturation and inspired oxygen fraction (FiO2) during bronchoscopy and we compared them related to weight, type of anesthesia and type of bronchoscope used. Mean basal saturation was 92 +/- 8.9% and end saturation was 92.8 +/- 10%. The basal FiO2 was 0.5 +/- 0.3 (0.21-1). There were more complications in patients weighting less than 1500 g and in those procedures made with rigid bronchoscopy (p < 0.05). There were no differences according to the anesthesia. Children who weight fewer than 1500 g and those who underwent rigid bronchoscopy suffered a descent in arterial oxygen saturation and needed higher FiO2 (p < 0.05). Bronchoscopy is a very useful technique and it is well tolerated in neonatal patients. We conclude that flexible fiberoptic bronchoscopy is safer than the rigid bronchoscopy, specially in children fewer under 1500 g.

[Respiratory deadspace and compliance measurements in neonates with congenital diaphragmatic hernia]

The mortality rate of infants with congenital diaphragmatic hernia (CDH) remains high, despite clinical improvements. Many attempts have been made to find accurate and reliable predictors of outcome. Deadspace (Vd/Vt) and dynamic compliance (DC) measured by single breath CO2 analysis may be useful to evaluate pulmonary function and perfusion. In the present study we analyse both parameters in patients with CDH. Nine patients with CDH were included for Vd/Vt and DC study. Measurements of arterial blood gases (pH, PO2, pCO2) were obtained, oxygenation index and alveolo-arterial difference calculated at diagnosis, preoperatively and postoperatively. Vd/Vt and DC were measured at the same moments by analysis of the CO2 espirogram. Statistical analysis was performed using Fisher exact test, ANOVA and Mann Whitney and Chi-square. The Vd/Vt was significant lower for the group of patients who survived (0.39 +/- 0.07 vs 0.64 +/- 0.14, p = 0.038). DC was significantly higher in the survivors group (1.39 +/- 0.30 vs 0.5 +/- 0.07, p = 0.011). The analysis of the evolutive Vd/Vt and DC (initial and preoperative) showed significant differences within both groups. Respiratory deadspace can be easily quantified in neonates with congenital diaphragmatic hernia providing an important insight regarding the efficiency of the airway-alveolus and its relationship to pulmonary blood flow. Vd/Vt and DC measurement constitute a reliable method to predict outcome in patients with CDH.

[Analysis of the cytosolic content of the pS2 protein in breast cancer]

OBJECTIVE

To analyze pS2 cytosolic levels in breast carcinomas and their correlation with different clinical characteristics of the patients and their tumours.

MATERIAL AND METHODS

Cytosolic pS2 levels were measured by radioimmunometric assay in tumours from 168 breast cancer patients.

RESULTS

The pS2 values ranged from 0 to 251 ng/mg protein (mean SD: 21.8 38.1; median: 7.9 ng/mg protein). These protein levels were significantly (p < 0.05) higher in premenopausal patients (27.6 45.2) than in postmenopausal patients (19.5 33.8). Intratumour pS2 levels were also significantly (p < 0.05) correlated with histologic grade of the tumours, and were higher in well diferentiated tumours (grade I: 28.8 42.8) than in moderately differentiated tumours (grade II: 19.7 35.6) and than in poorly differentiated tumours (grade III: 18.9 37.3). Similarly, significant differences in pS2 content were found between positive estrogen receptor (ER) tumours and ER-negative tumours (29.1 46.5 vs 11.3 15.9, respectively; p<0.0001), as well as between positive progesterone receptor (PR) tumours and PR-negative tumours (29.1 49.8 vs 15.3 21.5, respectively; p < 0.05).

CONCLUSIONS

The results suggest that pS2 may be a useful prognostic marker in breast cancer, and may also be useful to identify patients who are likely to benefit from hormone therapy.

The Cys-67 residue of HLA-B27 influences cell surface stability, peptide specificity, and T-cell antigen presentation

Cys-67 of HLA-B27 is located in the B pocket, which determines peptide-binding specificity. We analyzed effects of the Cys-67 --> Ser mutation on cell surface expression, peptide specificity, and T-cell recognition of HLA-B*2705. Surface expression was assessed with antibodies recognizing either native or unfolded HLA proteins. Whereas native B*2705 molecules predominated over unfolded ones, this ratio was reversed in the mutant, suggesting lower stability. Comparison of B*2705- and Cys-67 --> Ser-bound peptides revealed that the mutant failed to bind approximately 15% of the B*2705 ligands, while binding as many novel ones. Two peptides with Gln-2 found in both B*2705 and Cys-67 --> Ser are the first demonstration of natural B*2705 ligands lacking Arg-2. Other effects of the mutation on peptide specificity were: 1) average molecular mass of natural ligands higher than for B*2705, 2) bias against small residues at peptide position (P) 1, and 3) increased P2 permissiveness. The results suggest that the Cys-67 --> Ser mutation weakens B pocket interactions, leading to decreased stability of the mutant-peptide complexes. This may be partially compensated by interactions involving bulky P1 residues. The effect of the mutation on allorecognition was consistent with that on peptide specificity. Our results may aid understanding of the pathogenetic role of HLA-B27 in spondyloarthropathy.

Glutathionylation of the p50 subunit of NF-kappaB: a mechanism for redox-induced inhibition of DNA binding

The cellular redox status can modify the function of NF-kappaB, whose DNA-binding activity can be inhibited by oxidative, nitrosative, and nonphysiological agents such as diamide, iodoacetamide, or N-ethylmaleimide. This inhibitory effect has been proposed to be mediated by the oxidation of a conserved cysteine in its DNA-binding domain (Cys62) through unknown biochemical mechanisms. The aim of this work was to identify new oxidative modifications in Cys62 involved in the redox regulation of the NF-kappaB subunit p50. To address this problem, we exposed p50, both the native form (p50WT) and its corresponding mutant in Cys62 (C62S), to changes in the redox pair glutathione/glutathione disulfide (GSH/GSSG) ratio ranging from 100 to 0.1, which may correspond to intracellular (patho)physiological states. A ratio between 1 and 0.1 resulted in a 40-70% inhibition of the DNA binding of p50WT, having no effect on the C62S mutant. Mass spectrometry studies, molecular modeling, and incorporation of (3)H-glutathione assays were consistent with an S-glutathionylation of p50WT in Cys62. Maximal incorporation of (3)H-glutathione to the p50WT and C62S was of 0.4 and 0.1 mol of (3)H-GSH/mol of protein, respectively. Because this covalent glutathione incorporation did not show a perfect correlation with the observed inhibition in the DNA-binding activity of p50WT, we searched for other modifications contributing to the maximal inhibition. MALDI-TOF and nanospray-QIT studies revealed the formation of sulfenic acid as an alternative or concomitant oxidative modification of p50. In summary, these data are consistent with new oxidative modifications in p50 that could be involved in redox regulatory mechanisms for NF-kappaB. These postranslational modifications could represent a molecular basis for the coupling of pro-oxidative stimuli to gene expression.

Characterization of rpoB gene mutations in rifampicin resistant Mycobacterium tuberculosis strains isolated from pulmonary tuberculosis patients at 5 Mexican public hospitals

OBJECTIVE

To characterize the rpoB gene mutations of the rifampicin-resistant M. tuberculosis strains isolated in pulmonary tuberculosis patients from Mexico.

MATERIAL AND METHODS

Thirty-seven clinical M. tuberculosis isolates cultured on Löwenstein-Jensen media and obtained from consecutive tuberculosis patients in 5 public hospitals were analyzed by PCR and the INNO-LiPA Rif TB for amplification and detection of mutations associated with rifampicin resistance, respectively.

RESULTS

Twenty-three out of 37 isolates (62.2%) were found to be wild type (rifampicin susceptible), while 14 isolates (37.8%) contained mutations associated with rifampicin resistance. Seven out of the 37 isolates (18.9%) had a delta S1 mutation, in the nucleotide position number 511; one (2.7%) had a R4b mutation, in nucleotide H526D; five (13.5%) contained a R5 mutation, in nucleotide S531L; and one (2.7%) showed a double mutation delta S1/R4b.

CONCLUSION

According to the marker used (rifampicin resistance), at least five different strains of M. tuberculosis circulate among pulmonary tuberculosis patients in Mexico. rpoB gene mutations associated with rifampicin resistance are common in Mexico. A single mutation in nucleotide 511 was the most frequently observed, followed by single mutations in nucleotides S531L and H526D.

Lysozyme expression by breast carcinomas, correlation with clinicopathologic parameters, and prognostic significance

BACKGROUND

Here we evaluate the expression and prognostic value of lysozyme, a milk protein that is also synthesized by a significant percentage of breast carcinomas, in women with breast cancer.

METHODS

Lysozyme expression was examined by immunohistochemical methods in a series of 177 breast cancer tissue sections. Staining was quantified by using the HSCORE system, which considers both the intensity and the percentage of cells staining at each intensity. The prognostic value of lysozyme was retrospectively evaluated by multivariate analysis that took into account conventional prognostic factors.

RESULTS

A total of 126 of 177 carcinomas (69.4%) stained positive for this protein, but there were clear differences among them with regard to the intensity and percentage of stained cells. Lysozyme values were higher in well-differentiated and moderately differentiated tumors than in poorly differentiated tumors (P < .05). Similarly, lysozyme levels were higher in small and node-negative tumors than in large and node-positive tumors (P < .05). Moreover, results indicated that low lysozyme content predicted shorter relapse-free survival and overall survival (P < .005). Separate Cox multivariate analysis in subgroups of patients as defined by node status showed that lysozyme expression was an independent prognostic factor able to predict both relapse-free survival and overall survival in node-negative patients (P < .05).

CONCLUSIONS

Tumoral expression of lysozyme is associated with lesions of favorable evolution in breast cancer. This milk protein may be a new prognostic factor in patients with breast cancer.

Experimental and ab Initio Equilibrium Structure and Harmonic Force Field of 1,2,5-Oxadiazole

The equilibrium structure of 1,2,5-oxadiazole has been calculated ab initio at the CCSD(T) level using a polarized valence quadruple zeta basis set. The harmonic force field has also been calculated at the MP2/cc-pVTZ, B3LYP/6-311++G(3df, 2pd), and B3LYP/cc-pVQZ levels. These force fields have been subsequently scaled and further refined by fitting them to the experimental values of the vibrational fundamentals of three isotopomers and the centrifugal distortion constants of the parent molecule. The specific refinement of those scaled force constants particularly sensitive to the experimental data set was decisive for obtaining a more reliable harmonic potential. The resulting force fields are presented and used, together with the ground state rotational constants, to calculate an r(z) structure. The experimental r(0), r(s), and r(m) structures have also been determined. The different results have been compared and it is concluded that the ab initio structure is a good approximation of the equilibrium structure. It is also shown that the magnetic correction is not negligible, particularly for the inertial defect. Another interesting conclusion is that the anharmonicity of the C-H stretching might be unusually small. Copyright 2001 Academic Press.

Characterization and partial sequencing of species-specific sarcoplasmic polypeptides from commercial hake species by mass spectrometry following two-dimensional electrophoresis

The Merluccidae family comprises marine species, some of them of high commercial value and others less appreciated, whose commercialization in Europe under the generic name of "hake" is highly remarkable. The potential of proteomics was employed in this study with the aim of achieving the differential characterization of five different hake species: Merluccius merluccius (European hake), M. australis (Southern hake), M. hubbsi (Argentinian hake), M. gayi (Chilean hake), and M. capensis (Cape hake), some of them very closely related. Species-specific polypeptides were observed for the five hake species studied in isoelectric focusing (IEF) and/or two-dimensional electrophoresis (2-DE) high-resolution gels. The peptide mass maps of two polypeptide groups, previously selected by 2-DE analysis as potentially species-specific, were obtained by "in-gel" tryptic digestion, followed by matrix assisted laser desorption/ ionization-time of flight-mass spectrometry (MALDI-TOF-MS). Analysis of group A polypeptides (with pI in the range of 5.0-5.5 and molecular mass of 17 kDa), allowed the differential classification of the hake species into two groups: the East Atlantic coast group and the West Atlantic coast group. Moreover, the peptide mass-maps from the heat-resistant parvalbumin fraction (pI below 4.5; molecular mass <12 kDa) allowed the detection of a peptide characteristic of M. australis not present in the other four hake species tested. A specific 17 kDa protein from M. merluccius was also partially sequenced by nanospray-ion trap-tandem MS, revealing a high homology with rat nucleoside diphosphate kinase A (NDKA). This work opens the way to the application of proteomics to the differential characterization of commercial hake species at the molecular level.

[Polyps of the biliary tract: is their preoperative diagnosis possible?]

Bile duct polyps are a very uncommon cause of obstructive jaundice. We present our experience of three patients diagnosed in the last 10 years. Initial presentation usually takes the form of obstructive jaundice associated with abdominal pain, which simulates biliary lithiasis. The diagnosis is usually surgical. Although in some cases radiological studies and endoscopic retrograde cholangiopancreatography (ERCP) may sometimes detect bile duct polyps, exact diagnosis before surgery is very unusual. The radiological signs that suggest the existence of a bile duct polyp in the ERCP seem to be the presence of repletion defects, fixed unilaterally to the biliary conduit, without meniscus and without circumferential stenosis of the affected conduit. The most frequently found polyps are fibroinflammatory, and less frequently adenomatous.

A quantum mechanics/molecular mechanics study of the highly enantioselective addition of diethylzinc to benzaldehyde promoted by (R)-2-piperidino-1,1,2-triphenylethanol

The enantioselective addition of diethylzinc to benzaldehyde mediated by (R)-2-piperidino-1,1,2-triphenylethanol has been studied with the IMOMM procedure, using a RHF description for the quantum mechanical part of the calculation and the mm3(92) force field for the molecular mechanics part. Both the sign and the value of the observed enantioselectivity are well reproduced by the calculations, the relative energies of the four possible transition states being as follows: anti-Si (0.0 kcal.mol(-)(1)), syn-Re (2.7 kcal. mol(-)(1)), anti-Re (4.7 kcal.mol(-)(1)), syn-Si (5.9 kcal. mol(-)(1)). These energies show a perfect correlation with the bond distance in the transition state between zinc and the methylene unit of the ethyl group being transferred.

A quantum mechanics/molecular mechanics study of the highly enantioselective addition of diethylzinc to benzaldehyde promoted by (R)-2-piperidino-1,1,2-triphenylethanol

The enantioselective addition of diethylzinc to benzaldehyde mediated by (R)-2-piperidino-1,1,2-triphenylethanol has been studied with the IMOMM procedure, using a RHF description for the quantum mechanical part of the calculation and the mm3(92) force field for the molecular mechanics part. Both the sign and the value of the observed enantioselectivity are well reproduced by the calculations, the relative energies of the four possible transition states being as follows: anti-Si (0.0 kcal.mol(-)(1)), syn-Re (2.7 kcal. mol(-)(1)), anti-Re (4.7 kcal.mol(-)(1)), syn-Si (5.9 kcal. mol(-)(1)). These energies show a perfect correlation with the bond distance in the transition state between zinc and the methylene unit of the ethyl group being transferred.

A post-translational modification of nuclear proteins, N(G),N(G)-dimethyl-Arg, found in a natural HLA class I peptide ligand

Presentation of peptides derived from endogenous proteins by class I major histocompatibility complex molecules is essential both for immunological self-tolerance and induction of cytotoxic T-cell responses against intracellular parasites. Despite frequent and diverse post-translational modification of eukaryotic cell proteins, very few class I-bound peptides with post-translationally modified residues are known. Here we describe a natural dodecamer ligand of HLA-B39 (B*3910) derived from an RNA-binding nucleoprotein that carried N(G),N(G)-dimethyl-Arg. Although common among RNA-binding proteins, this modification was not previously known among natural class I ligands. The sequence of this peptide was determined by Edman degradation and electrospray ion trap mass spectrometry. The fragmentation pattern of the dimethyl-Arg side chain observed with this latter technique allowed us to unambiguously assign the isomeric form of the modified residue. The post-translationally modified ligand was a prominent component (1-2%) of the B*3910-bound peptide repertoire. The dimethyl-Arg residue was located in a central position of the peptide, amenable to interacting with T-cell receptors, and most other residues in the middle region of the peptide were Gly. These structural features strongly suggest that the post-translationally modified residue may have a major influence on the antigenic properties of this natural ligand.

Peptide specificity of the Amerindian B*3905 allotype: molecular insight into selection mechanisms driving HLA class I evolution in indigenous populations of the Americas

HLA-B*3905 is apparently restricted to Amerindian populations and presents a wide geographical distribution, from Mexico to Argentina. It differs from B*3901, one of the founder HLA class I alleles of Central and South Amerindians, by a single nucleotide substitution leading to an Asp74Tyr change in the gene product. The peptide specificity of the B*3905 protein was characterized by pool sequence analysis of B*3905-bound peptides and by sequencing of a set of individual ligands, using electrospray ion trap mass spectrometry. The results indicate a double effect of the B*3905 mutation. First, pocket B specificity was shifted towards an increased preference for His at peptide position 2, which is the main anchor for B39-bound peptides, relative to B*3901. Second, at peptide position 3 acidic residues were favored, and aromatic residues disfavored, relative to B*3901. These features approach the peptide specificity of B*3905 to B*3801 and B*1509, allotypes absent from Central and South Amerindians. Together with B*3909, B*3905 is the second HLA-B39 subtype whose polymorphism results in a shift of peptide specificity towards that of HLA-B allotypes absent from these populations. This suggests that HLA-B39 evolution in Central and South America may be an antigen-driven adaptive response, leading to generate antigen-presenting properties absent from the HLA class I repertoire of the ancestral population.

Phenotypic and genetic characterization of Lactococcus garvieae isolated in Spain from lactococcosis outbreaks and comparison with isolates of other countries and sources

The phenotypic and genetic analysis results for 84 isolates of Lactococcus garvieae (including 62 strains from trout with lactococcosis from four different countries, 7 strains from cows and water buffalos with subclinical mastitis, 3 from water, and 10 from human clinical samples) are presented. There was great phenotypic heterogeneity (13 different biotypes) based on the acidification of saccharose, tagatose, mannitol, and cyclodextrin and the presence of the enzymes pyroglutamic acid arylamidase and N-acetyl-beta-glucosaminidase. L. garvieae also exhibited high genetic diversity by pulsed-field gel electrophoresis (PFGE), with 19 different pulsotypes among the isolates of L. garvieae studied. Only epidemiologically related strains, like the Spanish and Italian fish isolates and the cow and water buffalo isolates, displayed a close genetic relationship by PFGE, while the strains isolated from sporadic clinical cases, like the human isolates, were genetically unrelated. Overall, a general correlation between phenotypic and genetic data was observed. Epidemiological analysis of biotype and PFGE results indicated that the trout lactococcosis outbreaks in Spain and Portugal and those in France and Italy were produced by genetically unrelated clones. In Spain, two different clones were detected; the outbreaks diagnosed from 1995 onward were produced by a clone (biotype 2, pulsotype A1) which, although genetically related, was different from the one that was responsible for the outbreaks studied between 1991 and 1994 (biotype 1, pulsotype B). The Portuguese isolate had a biochemical profile identical to that of the Spanish strain isolated from 1995 onward and is also genetically closely related to this strain (pulsotype A2). There was a close relationship between the two pulsotypes (E and F) found in the Italian isolates. The French isolate (biotype 3, pulsotype D) was not genetically related to any other L. garvieae fish isolate. These results suggest the existence of diverse infection sources for the different lactococcosis outbreaks.

[Obstetric trauma. A current problem?]

Advances in obstetric practice have decreased birth traumas in the last years, although they are still an important chapter in neonatal age. Between 1993-1998 a total of 21,375 stillborns were registered with a total of 309 birth injuries in 303 neonates (1.44%). The diagnoses were: 2 liver subcapsular hematomas, 105 cephalohematomas, 16 parietal fractures, 11 subdural hemorrhages, 107 clavicular fractures, 10 miscellaneous fractures, 8 soft tissue injuries, 25 facial nerve injuries and 25 braquial palsy. About relation between type of labor and birth trauma was found that clavicular fracture and cephalic vaginal delivery were associated in 50% of the cases, cephalohematoma and forceps in 51%, braquial palsy and vaginal delivery in 44% and forceps in 36%. High weight at birth was another risk factor for entities such as clavicular fracture and braquial palsy. We conclude that birth trauma is a pathology with a relevant incidence and their epidemiology factor had to be known.

Ex vivo bactericidal activity against group C Neisseria meningitidis in seronegative subjects

BACKGROUND

To determine the anti-meningococcal C immunological activity by adding functional tests (opsonophagocytosis) to the classical serology techniques.

SUBJECTS AND METHODS

42 adult volunteers were screened using serological methods (determination of total and bactericidal antibodies). Seronegative subjects were tested by opsonophagocytosis.

RESULTS

24 subjects (57%) showed serological evidence of previous contact with Neisseria meningitidis group C antigens: 19 subjects had both total and bactericidal antibodies, two subjects had only total antibodies and three subjects had only bactericidal antibodies. Of the 18 seronegative subjects, five showed ex vivo activity in killing curves with or without polymorphonuclear cells: two subjects exhibited only complement-mediated bactericidal activity, one subject only opsonophagocytosis, and two subjects exhibited both activities.

CONCLUSION

The addition of functional tests to the classical serological determination increases the evidence of previous contact with N. meningitidis antigens by 12%.

Identification of amino acid residues of transcription factor AP-2 involved in DNA binding

AP-2 is a cell-type specific, developmentally regulated transcription factor which has been described as a critical regulator of gene expression during vertebrate development and embryogenesis. Although the overall domains of this factor necessary for their activity have been identified, the exact identity of AP-2 amino acid residues responsible for its interaction with the DNA structure has not yet been described. Here, we describe the identification of a region of AP-2 which was protected by an oligonucleotide probe containing its binding site from trypsin digestion, monitored by peptide mapping by MALDI-TOF mass spectrometry. Furthermore, we analyzed the relative in vitro DNA-binding activity, the stimulatory potency on the AP-2-dependent APOE promoter, as well as the ability to inhibit the effect of the wild-type protein of each one of a set of single-site substitution AP-2 mutants spanning the identified region. Taken together, our data clearly demonstrate that the region between amino acid residues 252-260 of AP-2 is essential for its DNA-binding activity. Particularly, the individual substitution in any of the residues 253, 254, 255, 257 or 260 is sufficient for completely abolishing the interaction with DNA and the stimulation of APOE promoter activity. These results indicate a crucial role of this region in the formation of an active DNA-binding domain and strongly suggest that these residues provide direct contacts with the DNA structure at the AP-2 binding site.