Mismatches in genetic markers in a large family study.

The Hawaii Family Study of Cognition provided an opportunity to investigate the frequency and implications of non-agreement, or mismatches, between observed and expected genetic marker phenotypes of husbands, wives, and children. Mismatch data from 68 families in which one or both spouses were known not to be a biological parent were used to determine the rate of undeclared nonparentage in 1,748 families in which conventional relationships were claimed. Two independent approaches gave consistent estimates, suggesting that approximately 2.3% of the 2,839 tested children from these families were probably the result of infidelity, concealed adoption, or another event. About two-thirds of the mismatches detected were probably due to properties of the techniques employed.     

Congenital Baylisascaris sp. larval migrans in a newborn lamb

A 3-day-old domestic lamb, moribund since birth, was submitted as part of a diagnostic effort concerning weak newborn lambs due possibly to congenital Bluetongue virus infection. Gross lesions were consistent with such an event. Histologic examination of cerebrum and cerebellum revealed multiple granulomas, the age of which required prenatal development. These contained larvae compatible with those of Baylisascaris sp. This finding together with evidence that parents of children with neural larval migrans have been seropositive for ascarid antigen suggests that mammalian fetuses in general should be added to the list of those at risk for neural larva migrans due to ascarid parasites.     

Children's Memory of a Naturalistic Event Following Misinformation

Can children's reports of a naturalistic event be influenced by inaccurate postevent information? This study investigated conditions under which misinformation may or may not alter 6- and 9-year-old children's reports of a naturalistic event. Two weeks after participating in interactive play, 72 children listened to a narrative that included neutral and inaccurate information. Using a yes-no recognition test, misinformation acceptance and interference were measured. A recall test followed. Misinformation effects were assessed for 3 types of information. On the yes-no test, children evidenced significantly poorer memory for misled event items than for control event items. On the free-recall task, misinformation effects (i.e., suppression of event information) were found only for older children. However, overall, misinformation effects were dependent on the type of information. Results demonstrate that misleading information can, but does not necessarily, impair children's memory reports, and that the impairment is sometimes suppression of event information rather than intrusion of suggested information.     

Gastrointestinal bleeding in the pediatric patient.

Gastrointestinal hemorrhage in infants and children is a catastrophic event but is not associated with significant mortality except in those with a severe primary illness. Upper gastrointestinal bleeding in infants and young children is most often associated with stress ulcers or erosions, but in older children it may also be caused by duodenal ulcer, esophagitis, and esophageal varices. Lower gastrointestinal bleeding may be caused by a variety of lesions among which are infectious colitides, Meckel''s diverticulum, bleeding disorders, gastrointestinal allergy, and inflammatory bowel disease. Techniques of diagnosis and management are discussed.     

The shapin of psychiatry by science and humanism. II. An emerging synthesis of science and humanism.

Serological surveys of rubella antibody were carried out using the hemagglutination-inhibition test, with a view to studying the distribution of seroimmune individuals according to age and intermingling with other populations. Specimens were collected from different age groups including infants, children and adults, among the inhabitants of Montreal from 1963 to 1968. From the results obtained it was possible to establish the pattern of rubella antibody development in this urban community. Surveys were also conducted among the inhabitants of Les Iles de la Madeleine, a Canadian island in the Gulf of St. Lawrence, and among the population of Easter Island, an isolated island in the South Pacific remote from any large land mass.It was seen that, among the inhabitants of Montreal, presumably maternally acquired rubella antibody was present in 95% or more of the infants, the same percentage of seroimmune individuals as was found among the adult women 25 to 30 years of age. Passively acquired rubella antibodies decreased rapidly, attaining their lowest levels among children 1 to 2 years old. Rubella infection occurred in young children and its incidence rose steeply from school age to adolescence, leaving 7 to 9% of the adults without antibody. The highest geometric mean antibody titres were found among children 4 to 10 years of age.The same pattern of rubella antibody development was found among the population of Les Iles de la Madeleine, except that in adults the percentages of seropositives reached practically 100%. Antibody titres decreased with advancing age and became lower than those found among children.Detection of rubella antibody in serum samples derived from the inhabitants of Easter Island indicated that this population had experienced rubella infection not long before the Canadian Medical Expedition of 1964-1965. This status is determined from the high proportion of seroimmune individuals in each age group and the uniformly high antibody titre.Island populations appear to represent the ideal subjects for estimating the duration of the immunity conferred by any attenuated rubella vaccine that will eventually be licensed.     

An apparent interlocus gene conversion-like event at a putative tumor suppressor gene locus on human chromosome 6q27 in a Burkitt's lymphoma cell line.

A region of minimal deletion in B-cell non-Hodgkin's lymphoma (B-NHL) has recently been defined between D6S186 and D6S227 spanning 5-9 Mb at 6q26-q27, predicting the presence of at least one tumor suppressor gene (TSG) at this locus. During the construction of a deletion map in the B-NHL tumor panel, we report the identification of a Burkitt's lymphoma cell line, BL74, having an apparent homozygous deletion at the D6S347 locus, internal to the critical region. Since this case may facilitate the localization of the target TSG, a detailed structural molecular characterization and search for candidate genes were undertaken at this locus. While BL74 underwent a loss of heterozygosity at 6q26-q27, D6S347 was also likely subjected to a somatic interlocus gene conversion-like event between two homologous but distinct loci, resulting in the homozygous replacement of a 1860- to 2067-bp segment of one locus with the corresponding segment copied from the other locus. Two genes at this locus were identified, but their lack of expression in B-cell lineages tentatively excludes them as candidate TSGs. Another still unidentified gene at this locus may be disrupted by the gene conversion-like event, which would represent a novel mechanism of TSG inactivation.     

Hepatitis in a Housing Development: The Detection of Subclinical Infection

To detect the extent of subclinical infection during an outbreak of infectious hepatitis in a low-cost, high-density housing development, serum glutamic oxaloacetic transaminase (SGOT) levels were measured in 390 of the 1650 residents.Elevated SGOT values were found in 17.4% of those tested. Abnormal levels were more common in young children, occurring in 24.7% of those under 5 years of age and in 24.1% of those from 5 to 9 years of age.It was concluded that subclinical infection was widespread in the development, children under 10 years of age forming the principal reservoir. The concentration of many small children with poor personal hygiene favoured the spread of the infection.More extensive play areas and other facilities appropriate for large families, improved hygiene, dispersal of high-density housing units, and widespread use of gamma globulin in the event of an out-break are suggested as control measures.     

Molecular changes in thyroid neoplasia

All authors integrating the known facts into a model of thyroid carcinogenesis concur that two main histotypes of thyroid cancer exhibit different routes of molecular development. RET rearrangements are an initiating event in papillary carcinoma, and simultaneously the most characteristic mutation for this type of cancer. They are followed by further, not well recognized, mutations. RAS mutations are regarded as a crucial event in the development of follicular tumors already at the adenoma step, while in papillary cancer they belong to the spectrum of secondary mutations, enabling tumor progression. Aberrant DNA methylation, causing loss of P16 tumor supressor gene, may be a common event in both types of cancer. Aneuploidy is seen much more frequently in follicular than in papillary cancer, which also exhibits a low rate for loss of heterozygosity and microsatellite instability. Mutations of the P53 tumor supressor gene are a common feature of undifferentiated thyroid cancers and could be responsible for their aggressive phenotype. RET rearrangements have been proposed as identifying fingerprints for irradiation induced thyroid cancer in children. Our own data speak against this hypothesis. We noted a high frequency of RET/PTC3 mutations in a group of Polish children with papillary thyroid carcinoma, regarded as sporadic cancer.     

The polymerase-like core of brome mosaic virus 2a protein, lacking a region interacting with viral 1a protein in vitro, maintains activity and 1a selectivity in RNA replication.

Brome mosaic virus (BMV), a member of the alphavirus-like super-family of positive-strand RNA viruses, encodes two proteins required for viral RNA replication: 1a and 2a. 1a contains m7G methyltransferase- and helicase-like domains, while 2a contains a polymerase (pol)-like core flanked by N- and C-terminal extensions. Genetic studies show that BMV RNA replication requires 1a-2a compatibility implying direct or indirect 1a-2a interaction in vivo. In vitro, la interacts with the N-terminal 125-amino-acid segment of 2a preceding the pol-like core, and prior deletion studies suggested that this 2a segment was essential for RNA replication. We have now used protein fusions and deletions to explore possible parallels between noncovalent 1a-2a interaction and covalent fusion of similar protein domains in tobacco mosaic virus and to see whether the N-terminal 2a-1a interaction was the primary basis for 1a-2a compatibility in vivo. We found that 2a can function as part of a tobacco mosaic virus-like 1a-2a fusion and that a 2a segment (amino acids 162 to 697) comprising the pol-like core was sufficient to provide 2a functions in such a fusion. Unexpectedly, the unfused 2a core segment also supported RNA replication when it and wild-type la were expressed as separate proteins. Moreover, in gene reassortant experiments with the related cowpea chlorotic mottle virus, the unfused 2a core segment showed the same 1a compatibility requirements as did wild-type BMV 2a. Thus, the pol-like core of 2a must interact with la in a way that is selective and essential for RNA synthesis, and 1a-2a interactions are more complex than the single, previously mapped interaction of the N-terminal 2a segment with 1a.     

Poliovirus excretion in Guatemalan adults and children with HIV infection and children with cancer.

More than 20 patients with persistent poliovirus infections have been identified and reported to WHO. To date, almost all of these patients have had B-cell immune deficiency disorders. Since there are limited data on patients with HIV infection who have received oral poliovirus vaccine (OPV), we studied adults and children to determine if persons with acquired immunodeficiency due to HIV infection or cancer chemotherapy in a developing country setting had prolonged excretion of polioviruses. Stool samples from 94 HIV-infected children and 101 adults and 50 children surviving cancer in Guatemala City were cultured for polioviruses. No polioviruses were detected in any of the 195 persons with HIV infection or the 50 with cancer. The evidence from this and other studies indicates that the persistent poliovirus excretion in HIV-infected individuals is an unlikely event.     

Pleuropulmonary melioidosis in a Cambodian refugee.

A 47-year-old Cambodian refugee presented with an acute respiratory illness that featured consolidation of the lower lobe of the left lung and progressive involvement of the adjacent pleura caused by Pseudomonas pseudomallei. Initial difficulty in identifying the organism resulted in an inadequate duration of therapy. Chronic pleural disease followed, and the organism became resistant to many antibiotics during therapy. A diagnosis of pleuropulmonary melioidosis should be entertained and the microbiology laboratory alerted when patients with pneumonia who are from endemic areas are encountered, so that a diagnosis can be made early and the appropriate treatment begun.     

Internode length in Pisum. Gibberellins and the slender phenotype

Pea plants ( Pisum sativum L.) possessing the slender phenotype (conferred by the gene combination la cry^s ) have extremely long, thin internodes and are phenotypically similar to dwarf plants (possessing genes La and/or Cry ) that have been treated with a non-limiting dose of gibberellin (GA₃). In contrast to tall and dwarf plants, slender plants are virtually insensitive to treatment with AMO 1618, PP333 or GA₃ and addition of the "gibberellin-less" mutant gene na does not alter the phenotype of slender plants. Na slender segregates possessed lower levels of gibberellin-like substances than comparable dwarf segregates when extracts from shoots were assayed using the lettuce hypocotyl or rice seedling bioassays. In addition, na slenders possessed little or no gibberellin-like activity even though they possessed a slender phenotype. Thus the gene combination la cry^s causes slender plants to respond as if they are saturated with gibberellins for growth. In addition, the gene combinations la cry^s and le la cry^c (allele cry^c is less extreme in effect than cry^s ) are shown to be almost completely epistatic to the alleles at the na locus. All these results suggest that gibberellin levels are not important in determining the internode length of slender peas (genotype la cry^s ). The possible mechanisms by which this could occur are discussed.     

Early steps initiating a degradation pathway in Escherichia coli. Characterization of the first intermediate

Our previous studies demonstrated that a site-specific cleavage event initiates the degradation of large premature termination polypeptides of beta-galactosidase in Escherichia coli. We have isolated the first cleavage intermediate, the "B" polypeptide, by elution from sodium dodecyl sulfate-polyacrylamide gels. The NH2 terminus of this protein, determined by automated Edman degradation, was that of the wild-type molecule and thus established that the first cleavage event was at the COOH-terminal end. The sequence of the COOH-terminal end of the B polypeptide was determined by using the enzyme carboxypeptidase Y. Direct assignment of COOH-terminal residues was made by using o-phthaldialdehyde derivatization and the stoichiometry confirmed by a double-label analysis. The COOH-terminal end of the B polypeptide is at position 837 in the beta-galactosidase sequence. If a single endoproteolytic cleavage event was responsible, the cleavage would have occurred between 2 threonine residues (at positions 837 and 838) that are located within a hydrophobic domain. We have observed other covalent modifications that precede the appearance of the B polypeptide, but these do not appear to participate in signaling the first cleavage event. The structure of the COOH-terminal end of B suggests a high degree of specificity by the initial cleavage enzyme. We propose that this unique site serves as a specific signal and that exposure of this site to the specific cleavage enzyme controls the event initiating the degradation pathway.     

Stability and change in Tethyan planktic foraminifera across the Paleocene–Eocene transition

Examination of planktic foraminifera in the Tethys basin during the Paleocene–Eocene transition reveals two stasis intervals that are separated by a major saltation event coincident with the P–E short-term perturbation in global climate and oceanography. Changes occurred at many spatial and temporal scales as well as many taxonomic and ecologic hierarchical levels, though with various rates and magnitudes. The stasis intervals are marked by slow changes at the species level and account for 50% of the observed first and last appearances during a 2.5 Myr interval. The saltation event is marked by rapid changes at the species and morpho-guild levels and accounts for the remaining 50% of first and last appearances during an interval of about 100–200 kyr. Despite these changes, many taxonomic and ecologic units, such as the depth assemblages and genera, and faunal parameters, such as species richness and turnover rates, are stable with respect to the P–E perturbation. This coexistence of change and stability marks the crisis of Tethyan planktic foraminifera across the P–E transition and reveals the possible dynamics of ecological evolution.     

Horizontal transfer of a phosphatase gene as evidence for mosaic structure of the Salmonella genome.

The genomes of Escherichia coli and Salmonella typhimurium are similar with respect to base composition, chromosome size, and the order, orientation and spacing of genes, but differ with respect to some 29 'loops', regions unique to one species. To evaluate the genetic basis for the structure and organization of the enteric bacterial genomes, we examined the gene encoding a non-specific acid phosphatase (phoN) which maps to a loop at 96 min on the S.typhimurium chromosome. We detected atypical base composition, codon usage pattern and trinucleotide frequencies. The 1.4 kb region containing phoN had an overall base composition of 43% G+C, while the G+C content at the third positions of codons in the phoN reading frame is only 39%, much lower than the Salmonella chromosome which averages 52%. Non-specific acid phosphatase activity, assayed in 14 Gram-negative species, was detected only in Morganella morganii and Providencia stuartii, organisms with low genomic G+C contents. Upstream of the phoN gene in Salmonella is a sequence with high similarity to the oriT region of incFII plasmids, suggesting that the phoN gene, and perhaps the entire loop structure, was acquired by lateral transmission in a plasmid-mediated event.     

Lytic response of Escherichia coli cells to inhibitors of penicillin-binding proteins 1a and 1b as a timed event related to cell division.

In growing cultures of Escherichia coli, simultaneous inhibition of penicillin-binding proteins 1a and 1b (PBPs 1) by a beta-lactam efficiently induces cell lysis. However, the lytic behavior of cultures initiating growth in the presence of beta-lactams specifically inhibiting PBPs 1 suggested that the triggering of cell lysis was a cell division-related event, at least in the first cell cycle after the resumption of growth (F. Garcia del Portillo, A. G. Pisabarro, E. J. de la Rosa, and M. A. de Pedro, J. Bacteriol. 169:2410-2416, 1987). To investigate whether this apparent correlation would hold true in actively growing cells, we studied the lytic behavior of cultures of E. coli aligned for cell division which were challenged with beta-lactams at different times after alignment. Cell division was aligned either by nutritional shift up or by chromosome replication alignment. Specific inhibition of PBPs 1 with the beta-lactam cefsulodin resulted in a delayed onset of lysis which was coincident in time with the resumption of cell division. The apparent correlation between the initiation of lysis and cell division was abolished when cefsulodin was used in combination with the PBP 2-specific inhibitor mecillinam, leading to the onset of lysis at a constant time after the addition of the beta-lactams. The results presented clearly argue in favor of the hypothesis that the triggering of cell lysis after inhibition of PBPs 1 is a cell division-correlated event dependent on the activity of PBP 2.     

Analysis of bacterial communities in a municipal duck pond during a phytoplankton bloom and isolation of Anatilimnocola aggregata gen. nov., sp. nov., Lacipirellula limnantheis sp. nov. and Urbifossiella limnaea gen. nov., sp. nov. belonging to the phylum Planctomycetes

Waterbodies such as lakes and ponds are fragile environments affected by human influences. Suitable conditions can result in massive growth of phototrophs, commonly referred to as phytoplankton blooms. Such events benefit heterotrophic bacteria able to use compounds secreted by phototrophs or their biomass as major nutrient source. One example of such bacteria are Planctomycetes, which are abundant on the surfaces of marine macroscopic phototrophs; however, less data are available on their ecological roles in limnic environments. In this study, we followed a cultivation-independent deep sequencing approach to study the bacterial community composition during a cyanobacterial bloom event in a municipal duck pond. In addition to cyanobacteria, which caused the bloom event, members of the phylum Planctomycetes were significantly enriched in the cyanobacteria-attached fraction compared to the free-living fraction. Separate datasets based on isolated DNA and RNA point towards considerable differences in the abundance and activity of planctomycetal families, indicating different activity peaks of these families during the cyanobacterial bloom. Motivated by the finding that the sampling location harbours untapped bacterial diversity, we included a complementary cultivation-dependent approach and isolated and characterized three novel limnic strains belonging to the phylum Planctomycetes.     

Cloning and characterization of upp, a gene encoding uracil phosphoribosyltransferase from Lactococcus lactis.

Uracil phosphoribosyltransferase catalyzes the key reaction in the salvage of uracil in many microorganisms. The gene encoding uracil phosphoribosyltransferase (upp) was cloned from Lactococcus lactis subsp. cremoris MG1363 by complementation of an Escherichia coli mutant. The gene was sequenced, and the putative amino acid sequence was deduced. The promoter was mapped by both primer extension and analysis of beta-galactosidase expressed from strains carrying fusion between upp promoter fragments and the lacLM gene. The results showed that the upp gene was expressed from its own promoter. After in vitro construction of an internal deletion, a upp mutant was constructed by a double-crossover event. This implicated the utilization of a plasmid with a thermosensitive origin of replication and a new and easy way to screen for double crossover events in both gram-positive and gram-negative bacterial strains. The phenotype of the uracil phosphoribosyltransferase-deficient strain was established. Surprisingly, the upp strain is resistant only to very low concentrations of 5-fluorouracil. Secondary mutants in thymidine phosphorylase and thymidine kinase were isolated by selection for resistance to high concentrations of 5-fluorouracil.     

Glyphosate-resistant goosegrass. Identification of a mutation in the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase

The spontaneous occurrence of resistance to the herbicide glyphosate in weed species has been an extremely infrequent event, despite over 20 years of extensive use. Recently, a glyphosate-resistant biotype of goosegrass (Eleusine indica) was identified in Malaysia exhibiting an LD(50) value approximately 2- to 4-fold greater than the sensitive biotype collected from the same region. A comparison of the inhibition of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity by glyphosate in extracts prepared from the resistant (R) and sensitive (S) biotypes revealed an approximately 5-fold higher IC(50)(glyphosate) for the (R) biotype. Sequence comparisons of the predicted EPSPS mature protein coding regions from both biotypes revealed four single-nucleotide differences, two of which result in amino acid changes. One of these changes, a proline to serine substitution at position 106 in the (R) biotype, corresponds to a substitution previously identified in a glyphosate-insensitive EPSPS enzyme from Salmonella typhimurium. Kinetic data generated for the recombinant enzymes suggests that the second substitution identified in the (R) EPSPS does not contribute significantly to its reduced glyphosate sensitivity. Escherichia coli aroA- (EPSPS deficient) strains expressing the mature EPSPS enzyme from the (R) biotype exhibited an approximately 3-fold increase in glyphosate tolerance relative to strains expressing the mature EPSPS from the (S) biotype. These results provide the first evidence for an altered EPSPS enzyme as an underlying component of evolved glyphosate resistance in any plant species.     

Absceso tiroideo. Serie de casos y revisión de la literatura

Thyroid abscess is rare in children but the presence of previous thyroid disease, and congenital remanants such as a pyriform sinus fistula, are predisposing factors. The classical presentation consists of fever, cervical pain and a painful mass. The diagnosis is confirmed through clinical findings, and by diagnostic imaging (ultrasound and computerized axial tomography). A barium swallow must be performed in order to detect a fistula and to consider surgical drain. We present the cases of thyroid abscess in five patients who were admitted in four medical centers (Fundación Cardioinfantil, Hospital Universitario San Ignacio, Clínica infantil de Colsubsidio and Hospital de la Misericordia) in Bogotá, Colombia between 2000 and 2010.