High Proportion Of Carriers Research Articles

Results of a study of parvovirus B19 (Parvoviridae, Parvovirinae, Erythroparvovirus, Primate erythroparvovirus 1) prevalence and circulation activity in socially significant categories of the population

Currently, along with the increasing need of medical organizations for blood preparations, algorithms for laboratory testing of blood donors are not available for all infections with hemo-contact mechanism of transmission. A representative example is infection caused by parvovirus В19. Purpose of the study. The article presents the results of the original study, the purpose of which was to study the prevalence of antibodies to parvovirus B19 and the activity of the circulation of this virus in socially important categories of the population. Material and methods. The materials of the study were blood samples from blood donors of Saint Petersburg, as well as parvovirus В19 sequences isolated from DNA-positive plasma samples. Results and discussion. According to the results of the laboratory examination, a high proportion of carriers of virus-specific IgG antibodies was found in studied group of donors, which confirms the previous infection of parvovirus B19 in them and illustrates the high prevalence of infection in this socially significant group. Based on the results of the blood preparations testing, the presence of parvovirus DNA В19 in a significant number of samples was determined by polymerase chain reaction method. This indicates an current parvovirus infection in the examined donors and points to a high epidemiological risk of the blood products obtained from them. Sequencing and phylogenetic analysis of a fragment of the VP1 gene demonstrated that the studied isolates belonged to А1 genotype and its subtype 1А2, which correlates with the genotypes of parvovirus В19 circulating in the European Union and Asia. In addition, two previously unknown В19 parvovirus isolates were isolated, the nucleotide sequences of which were deposited into the international GenBank database. Conclusion. Based on the results of the study, it is justified to include testing of blood samples for markers of В19 parvovirus infection in existing algorithms of laboratory examination of donors, which will ensure prevention of hemo-contact infection of blood recipients with parvovirus В19.

Increased activation of blood coagulation in pregnant women with the Factor V Leiden mutation

BackgroundThe risk of venous thromboembolism is enhanced in pregnant carriers of the Factor V Leiden mutation. The primary aim of the study was to compare prothrombin fragments 1+2, soluble fibrin and D-dimer levels in pregnant Factor V Leiden mutation carriers with those in non-carriers. Secondary aims were to evaluate whether these biomarkers could predict placenta-mediated complications or venous thromboembolism, and to study blood coagulation after caesarean section with thromboprophylaxis and after vaginal delivery without thromboprophylaxis. Material/MethodsProthrombin fragments 1+2, soluble fibrin and D-dimer levels were studied longitudinally in 476 carriers with singleton pregnancies from gestational weeks 23–25 until 8–10weeks postpartum. ResultsProthrombin fragments 1+2 and D-dimer levels gradually increased during pregnancy. D-dimer levels were higher in carriers, both during pregnancy and puerperium, compared to non-carriers. D-dimer levels above 0.5mg/l were found in about 30% and 20% of the heterozygous carriers at 4–5 and 8–10weeks postpartum, respectively. Soluble fibrin levels were mainly unchanged during pregnancy, with no difference between carriers and non-carriers. Biomarker levels were similar in carriers with uncomplicated and complicated pregnancies. ConclusionHigher D-dimer levels indicate increased blood coagulation and fibrinolysis activity in carriers. The high proportion of carriers with D-dimer levels exceeding 0.5mg/l postpartum must be considered when assessing the probability of venous thromboembolism. Large overlaps in biomarker levels in normal and complicated pregnancies suggest that these biomarkers cannot be used as predictors. Thromboprophylaxis following caesarean section may prevent increased activation of blood coagulation.

Exploring psychological responses to genetic testing for Lynch Syndrome within the family context.

Genetic testing for hereditary cancer susceptibility syndromes is a family-centered process. Nonetheless, little research has explored how the family context affects psychological responses to genetic testing. We examine how personal test results and the test results of immediate and extended family members shape responses to genetic testing. Individuals at risk of carrying a mutation associated with an inherited cancer susceptibility syndrome (Lynch syndrome) received genetic testing. Six months after receiving their results, participants reported on cancer distress, cancer worry, and depressive symptoms. Among mutation carriers for Lynch syndrome, the higher the proportion of carriers in their immediate family, the less cancer worry and distress they reported. In contrast, mutation carriers and non-carriers with a high proportion of carriers in their immediate family and mutation carriers with a high proportion of carriers in their extended family were at elevated risk for clinically significant levels of depressive symptoms. Personal test results alone are not highly predictive of psychological outcomes. Instead, the interaction between personal and family test results, or in some cases, family test results alone, predict key psychological outcomes. The current research has important implications for genetic counseling and intervention efforts. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Carriage of antibiotic-resistant pneumococci in a cohort of a daycare center.

To define epidemiologic relationships to determine the prevalence and potential risk factors for nasopharyngeal colonization by antibiotic-resistant pneumococci, their serotypes and their antibiotic susceptibility patterns in children attending a daycare center (DCC). A prospective cohort study was conducted among children (n = 53) attending the DCC at Hospital Infantil de México Federico Gómez, which is staffed by 20 employees. Patients were enrolled in the study during a two-year period from September 1997 to September 1999. All the participants were followed prospectively, swabbing them every four months. The strains recovered were typed and screened for susceptibility to several antibiotics. The daycare records were reviewed also. Odds ratios and fisher's exact test: or chi square test of significance were computed from contingency tables as appropriate. Exact 95% confidence intervals were computed for odds ratios. Data analysis was performed using Epi statistics program version 6.04 a. Pneumococci were recovered from 45/53 of the infants at one or more visits. A total of 178 isolates were carried. The carriage rate was 47%. Only 7 adults acquired pneumococci during the study. Types 6, 14, 19 and 23 were prevalent and represented 77% of the total. Antibiotic-resistant strains were higher to penicillin and erythromycin. Children were frequent carriers of pneumococci, the rate of carriage was high in infancy and tended to decrease with age. The types commonly carried by children were the same as those causing invasive disease. There is a high proportion of carriers with antibiotic-resistant S. pneumoniae strains. Children who have had frequent antimicrobial courses are at particular risk.

Bilan épidémiologique d’un échantillon de 91 rats (Rattus norvegicus) capturés dans les égouts de Lyon

91 rats captured in 1982 in the sewers of Lyon (France) have been examined for the presence of some microorganisms implicated in infections transmissible to man, by direct examination, bacteriological culture or detection of specific antibodies. Bacteriological results have shown a high proportion of carriers of Yersinia enterocolitica and frederiksenii (29%), of Pasteurella pneumotropica (29%), of Staphylococcus aureus (53%), and of Campylobacter jejuni (18%), a low proportion of carriers of Salmonella typhimurium (6%) and Leptospira (7%), and an absence of Listeria. Immunological reactions were often positive with Leptospira (21%), sometimes with Salmonella typhimurium, and always negative with Yersinia and Listeria. This work is a contribution to the knowledge of the health status of sewer rats considered to be an important public health risk as transmitters of anthropozoonoses.

Hb Potomac (101 Glu replaced by Asp): speculations on placental oxygen transport in carriers of high-affinity hemoglobins

Blood from a woman with unexplained erythrocytosis had increased oxygen affinity, but no abnormality could be detected by electrophoresis or chromatography of her hemolysate. Separation of the tryptic peptides of her beta chains disclosed two half-sized peaks in the regions of beta T-11. The faster of these was abnormal, with the structure beta 101 Glu replaced by Asp. The new hemoglobin was called "Potomac." Three of the proband's four surviving siblings and both of her children were carriers. Differences in the ratio of carrier: normal children born to male of female carriers of 23 other high-affinity hemoglobins were not significant. The high proportion of carriers in this kindred was probably due to chance alone, and not because high maternal oxygen affinity interfered with oxygen transport to fetuses with normal hemoglobin.

Hb Potomac (101 Glu → Asp): Speculations on Placental Oxygen Transport in Carriers of High-Affinity Hemoglobins

Abstract Blood from a woman with unexplained erythrocytosis had increased oxygen affinity, but no abnormality could be detected by electrophoresis or chromatography of her hemolysate. Separation of the tryptic peptides of her beta chains disclosed two half-sized peaks in the regions of beta T- 11. The faster of these was abnormal, with the structure beta 101 Glu replaced by Asp. The new hemoglobin was called “Potomac.” Three of the proband's four surviving siblings and both of her children were carriers. Differences in the ratio of carrier: normal children born to male of female carriers of 23 other high-affinity hemoglobins were not significant. The high proportion of carriers in this kindred was probably due to chance alone, and not because high maternal oxygen affinity interfered with oxygen transport to fetuses with normal hemoglobin.

Electrical transport properties and preparation of the metal-ammonia compound lithium tetraammine

On specimens of the compound lithium tetraammine, Li(NH 3) 4, the resistance from 10 to 100°K and the magnetoresistance at 4.2 and 1.66 K have been measured. Measurements were made using a probeless, mutual inductance technique. Specimen preparation and aspects of the measurement technique used in preparing well mixed, homogeneous specimens are described. The resistivity shows several anomalies in the solid phase, one of which has also been observed in thermal measurements and is associated with a transition from an fcc to an hcp structure. The second, near 69 K, has not been observed in thermal measurements. It is suggested that this anomaly is characteristic of the compound Li(NH 3) 4 and may be a Martensitic or magnetic transition. The magnetoresistance is large with a marked decrease in slope above 50 kG. These results are compared with standard galvanomagnetic theory for compensated and uncompensated metals. In conjunction with arguments based on a free electron construction of the Fermi surface, it is concluded that lithium tetraammine is probably an uncompensated metal with a high proportion of carriers in open orbits.