PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “shared variables”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources

Determinants of the quantity of hepatitis C virus RNA.

To test the hypothesis that person-to-person variability in blood levels of hepatitis C virus (HCV) RNA can be explained, the quantity of HCV RNA was assessed in 969 persons who acquired HCV infection in the context of injection drug use. Serum HCV RNA levels ranged from 200,000 to >120 million equivalents/mL (the linear range of the assay). The median log10 HCV RNA level was 0.46 higher in 468 human immunodeficiency virus (HIV)-positive persons than in 501 HIV-negative persons (P<.001). In addition, among HIV-negative persons, lower HCV RNA levels were independently associated with younger age (P<.001), ongoing hepatitis B infection (P=.005), and the absence of needle sharing (P=.02). However, >90% of the person-to-person HCV RNA level variability was not explained by these sociodemographic, environmental, and virologic factors. Additional research is necessary to ascertain what determines the level of HCV RNA in blood.

Adult↗

Primary structure and phylogenetic relationships of glyceraldehyde-3-phosphate dehydrogenase genes of free-living and parasitic diplomonad flagellates.

Complete nucleotide sequences have been established for two genes (gap1 and gap2) coding for glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) homologs in the diplomonad Giardia lamblia. In addition, almost complete sequences of the GAPDH open reading frames were obtained from PCR products for two free-living diplomonad species, Trepomonas agillis and Hexamita inflata, and a parasite of Atlantic salmon, an as yet unnamed species with morphological affinities to Spironucleus. Giardia lamblia gap1 and the genes from the three other diplomonad species show high similarity to each other and to other glycolytic GAPDH genes. All amino-acyl residues known to be highly conserved in this enzyme are also conserved in these sequences. Giardia lamblia gap2 gene is more divergent and its putative translation reveals the presence of a cysteine and serine-rich insertion resembling a metal binding finger. This motif has not yet been noted in other GAPDH molecules. All sequences contain an S-loop signature with characteristics close to those of eukaryotes. In phylogenetic reconstructions based on the derived amino acid sequences with neighbor-joining, parsimony and maximum-likelihood methods the four typical GAPDH sequences of diplomonads cluster into a single clade. Within this clade, G. lambia gap1 shares a common ancestor with the rest of the genes. The latter are more closely related to each other, indicating an early separation of the lineage leading to the genus Giardia from the lineage encompassing the morphologically less differentiated genera, Trepomonas, Hexamita and that of the unnamed species. This result is discordant with the orthogonal evolution of diplomonads suggested on the basis of comparative morphology. In neighbor-joining reconstructions G. lamblia gap2 occupies a variable position, due to its great divergence. In parsimony and maximum likelihood analysis however, it shares a most recent common ancestor with the typical G. lamblia gap1 gene, suggesting that it diverged after the separation of the Giardia lineage. The position of the diplomonad clade in broader phylogenetic reconstructions is firmly within the typical cytosolic glycolytic representatives of GAPDH of eukaryotes.

Animals↗

Comparative analysis of the gait disorder of normal pressure hydrocephalus and Parkinson's disease.

OBJECTIVES: Comparative gait analyses in neurological diseases interfering with locomotion are of particular interest, as many hypokinetic gait disorders have the same main features. The aim of the present study was (1) to compare the gait disturbance in normal pressure hydrocephalus and Parkinson's disease; (2) to evaluate which variables of the disturbed gait pattern respond to specific treatment in both diseases; and (3) to assess the responsiveness to visual and acoustic cues for gait improvement. METHODS: In study 1 gait analysis was carried out on 11 patients with normal pressure hydrocephalus, 10 patients with Parkinson's disease, and 12 age matched healthy control subjects, on a walkway and on a treadmill. In study 2, patients with normal pressure hydrocephalus were reinvestigated after removal of 30 ml CSF, and patients with Parkinson's disease after administration of 150 mg levodopa. In part 3 visual cues were provided as stripes fixed on the walkway and acoustic cues as beats of a metronome. RESULTS: The gait disorder in both diseases shared the feature of a reduced gait velocity, due to a diminished and highly variable stride length. Specific features of the gait disturbance in normal pressure hydrocephalus were a broad based gait pattern with outward rotated feet and a diminished height of the steps. After treatment in both diseases, the speed increased, due to an enlarged stride length, now presenting a lower variability. All other gait variables remained unaffected. External cues only mildly improved gait in normal pressure hydrocephalus, whereas they were highly effective in raising the stride length and cadence in Parkinson's disease. CONCLUSION: The gait pattern in normal pressure hydrocephalus is clearly distinguishable from the gait of Parkinson's disease. As well as the basal ganglia output connections, other pathways and structures most likely in the frontal lobes are responsible for the gait pattern and especially the disturbed dynamic equilibrium in normal pressure hydrocephalus. Hypokinesia and its responsiveness to external cues in both diseases are assumed to be an expression of a disturbed motor planning.

Aged↗

Characterization of antibodies to nerve growth factor: assay-dependent variability in the cross-reactivity with other neurotrophins.

The neurotrophin family of growth factors consists of proteins sharing a sizable degree of amino acid sequence and structural homology. These similarities greatly increase the probability that antibodies directed against any single neurotrophin may cross-react with other family-members. Various investigators have documented such cross-reactivity can occur under experimental conditions, although the extent of cross-reactivity reported in different studies has varied greatly. Although the use of different antibody preparations may have contributed to the differing degrees of cross-reactivity observed, it is important to note that different assay conditions were also used to evaluate cross-reactivity in the various studies. Little information is currently known about how antibody-antigen interactions vary as a function of the assay conditions used for the evaluation. The present study addressed this question by evaluating the cross-reactivity occurring between various neurotrophins and a single preparation of antibodies directed against purified mouse nerve growth factor-beta (beta-NGF) in a wide variety of immunological assay systems. Our results indicate that cross-reactivity between NGF antibodies and related neurotrophins can vary greatly depending upon the assay system chosen for the evaluation. These data strongly argue against transferring cross-reactivity data across various assay systems.

Animals↗

A computer-assisted case report and diagnosis system: sharing the knowledge database ADM and using hypermedia techniques.

The practice of medicine is characterized by its great variability and by many rare diseases. When the medical students work in hospital units, they must learn the general medical practice in the care of the patient. The purpose of this work was to present a French multifunction decision aid system using artificial intelligence techniques and Hypercard tools for different modules. Through an ergonomic interface, the system assists the user in the construction of medical observations, suggests diagnostic hypothesis, provides documentation and helps the user perform retrieval tasks. The knowledge comes from senior experts and from the pre-existent and large knowledge database, ADM.

Computer Peripherals↗

National sharing of cadaveric isolated intestinal allografts for human transplantation: a feasibility study.

UNLABELLED: Most isolated intestinal graft losses are immunological. We conducted a pilot study to evaluate the feasibility of national sharing of HLA no-mismatch allografts for cadaveric isolated intestinal transplantation. METHODS: UNOS data were analyzed in a theoretical model. Part I: All solid organ donors between 1/95-8/97 who would have met criteria for bowel donation were considered potential donors for all recipients who actually received isolated intestinal transplants during this period. We then determined how many donor intestines could have been directed to no-mismatch candidates had national sharing been in place. Donor exclusion criteria were CMV+ donors to CMV- recipients, hemodynamic instability, age >50, size mismatch (donor weight greater than recipient), and obesity. Mean and median waits for transplants, as well as theoretical mean and median waits for transplants that would have occurred given national sharing, were calculated. Part II: We estimated, based on registry graft survival data, the number of intestinal transplants necessary to demonstrate a no-mismatch graft survival advantage at 2 years. RESULTS: Part I: Although no actual cadaveric no-mismatch transplant was performed, 12-17% of patients could have received no-mismatch allografts had sharing been in place, using various donor acceptance criteria. The impact on waiting time was variable. Part II: Accepting a 15% rate of no-mismatch cases and a survival advantage of 10% at 2 years, 793 transplants would be required to prove an advantage to HLA matching at P<0.05. If the graft survival advantage were 20% at 2 years, the time to show significance would be approximately 5 years. Using early acute rejection as an endpoint could require fewer transplants (93), and only a few years to complete the study. CONCLUSIONS: National sharing of cadaveric isolated intestinal allografts is feasible. Median waits would not be significantly increased. The time necessary to prove graft survival advantage would be considerable, but a difference in the rate of acute rejection could be seen within 2 years. Additionally, a national sharing arrangement might improve the overall outcome of isolated intestinal transplantation.

Cadaver↗

Prophylaxis and treatment of venous thromboembolism in individuals with inherited thrombophilia.

Venous thromboembolism (VTE) susceptibility genes are widely diffuse in the general population, but clinical penetrance of genotypes is incomplete and has variable expressivity. Therefore, the indiscriminate search for carriers is of doubtful utility and potentially detrimental for screened individuals. A targeted screening in kindreds in which VTE already occurred can be more fruitful in identifying individuals sharing with the proband one or more known susceptibility genes (possibly cosegregating with other ones still unknown). Clinical penetrance is variable, and is higher in the relatively rare deficiencies of antithrombin (AT), protein C (PC), or protein S (PS), and lower in the presence of the common polymorphisms factor V Leiden and prothrombin G20210A. Women with inherited thrombophilia should be warned about the thrombotic risk associated with the use of oral contraceptives or hormonal replacement treatment. Moreover, prophylaxis during puerperium and surgery or after trauma is warranted. The absolute risk associated with such situations is low but not negligible in the presence of deficiencies of AT, PC, or PS, homozygous conditions, and carriership of multiple defects. In such cases primary prophylaxis should be applied also during pregnancy and in general should be more stringent; moreover, in these patients the option for indefinite duration of secondary anticoagulant prophylaxis after VTE should be considered because of the relevant risk of recurrent VTE. In all cases, a careful balance of benefits and risks associated with prophylactic measures should be achieved, and patient preferences should be considered.

Blood Coagulation Disorders, Inherited↗

Subjective intoxication in response to alcohol challenge: heritability and covariation with personality, breath alcohol level, and drinking history.

BACKGROUND: Numerous studies have identified differences in subjective response to alcohol in subjects differentiated by family history of alcoholism. Results suggest that genetic influences on individual variation in subjective response to alcohol may be a mechanism for genetic effects on alcohol problems. However, direct evidence for genetic effects on subjective response to alcohol is very limited. METHODS: In a sample of 99 adult twin pairs, we studied genetic influences on subjective intoxication after alcohol challenge. The twins ingested a standard dose of ethanol (0.70 g/kg for men/0.65 g/kg for women), and two measures of subjective response to alcohol were assessed. RESULTS: Genetic effects on variation in subjective intoxication reported 1 hr after drinking were significant and substantial: heritability was 0.60 for a 22-item scale and 0.48 for a brief 2-item measure. Self-report measures of neuroticism, psychasthenia, hostility, and family problems shared significant genetic covariation with subjective intoxication. Achieved breath alcohol level, rate of change in breath alcohol on the descending limb, and individual drinking history all shared familial variation with subjective intoxication. No significant genetic effects for subjective intoxication were found 2 hr after drinking, but familial influences remained present, and many of the same personality, drinking history, and breath alcohol variables were predictive of intoxication. CONCLUSIONS: Subjective response to alcohol is heritable, and genetic effects on subjective intoxication are partly shared with genetic effects on personality.

Adult↗

Determination of sibship in any two persons.

BACKGROUND: Parentage testing laboratories may be asked to provide genetic evidence that two persons are or are not related, when no other relatives are available for study. Simple methods using autosomal, codominant, unlinked genetic systems can determine if two people are blood relatives (e.g., siblings). STUDY DESIGN AND METHODS: The odds ratios (full sibship index) of true sibling pairs were determined from two-child paternity cases and compared with regionally and racially matched control pairs of unrelated children. The sharing of two, one, or no alleles was observed in pairs of children at three independent, polymorphic VNTR (variable number of tandem repeat) sequences loci. The sibship index was calculated as (the chance that an observation would occur if two children were siblings) divided by (the chance that it would occur if the two were unrelated). Sibship indices and the frequencies of shared alleles were determined for 20 sibling pairs and 20 control pairs. RESULTS: Sibship index values were less than 1 in all 20 pairs of unrelated children. Sibship index values were greater than 100 in nine pairs of siblings (45%), between 10 and 100 in five pairs (25%), between 1 and 10 in four pairs (20%), and less than 1 in two pairs (10%). Siblings shared two alleles in 17 of 60 observations (28.3%); controls shared two alleles in 0 of 60 observations (0%). CONCLUSION: The sharing of one allele and the sharing of no alleles at a polymorphic locus of high heterozygosity provide limited information for and against sibship, respectively. The sharing of two alleles produces strong evidence favoring sibship. In a given case, the study of more than three polymorphic loci of high heterozygosity may be needed to develop the evidence that two people are siblings. The general logic and methods used for siblings apply to kinship analyses of other two-person pedigrees.

Alleles↗

Nucleotide sequence analysis of the 3'-terminal region of two Korean isolates of lily symptomless Carlavirus and expression of the coat protein in E. coli.

The 3'-terminal regions of the genomic RNAs of two Korean isolates of the lily symptomless Carlavirus (LSV), LSV-Ko and LSV-KII, were cloned and their nucleotide sequences were determined. The nucleotide sequence analysis and protein analysis by the Western blot revealed that E. coli expressed a 32-kDa protein that is the viral coat protein (CP) for the LSV. The two Korean strains share 98.4% and 98.3% sequence identities at the nucleotide and amino acid levels, respectively. The CP gene of LSV-Ko showed 99.1% and 87.0% nucleotide sequence identities, and 99.0% and 96.6% amino acid sequence identities with those of the Netherlands and the Japanese LSV strains, respectively. A pairwise amino acid sequence comparison revealed a sequence similarity of 29.6% to 69.8% between LSV-Ko and other species of the carlavirus. The 16 kDa protein of LSV-Ko shares 17.6% to 42.7% amino acid similarity with those of 8 other the carlaviruses, and they are variable in the N-terminal region. The Cys repeated zinc finger nucleic acid binding domain was found in the 16 kDa protein for all of the LSV strains. Sequence comparisons of the 7 kDa protein of LSV in the strain level showed significant identities from 100.0% to 98.4%. LSV-Ko shares 21.9% to 42.2% amino acid similarity with those of 8 other carlaviruses, 4 members of the potexviruses, and a closterovirus. LSV is closely related to blueberry scorch virus (BISV) based upon the phylogenetic tree analyses of the three proteins, indicating LSV to be a quite distinct member of the genus Carlavirus.

Amino Acid Sequence↗

A cross-reactive anti-myelin basic protein idiotope in cerebrospinal fluid cells in multiple sclerosis.

We wanted to find evidence of antibody to myelin basic protein (MBP) in patients with MS by detecting their shared usage of immunoglobulin genes. As demonstrated by the idiotopes (i.d.) of murine monoclonal antibody to peptides of MBP, there is limited use of the variable (V) region immunoglobulin genes for the immune response in mice to this encephalitogenic protein. Cross-reactive Ids have been detected across different murine strains and shared by T and B cells. One cross-reactive Id, designated as 845D3 Id, is located on the V region of kappa light chains of two murine monoclonal antibodies, one to MBP peptide 80-89 and the other to MBP peptide acetyl 1-9. To examine the occurrence of 845D3 Id in MS, we used the V region of a light chain (VL) of one of the monoclonal antibodies to probe the VL genes expressed in B cells in CSF of 50 patients (31 MS and 19 non-MS). The VL genes expressed in B cells found in CSF were amplified by polymerase chain reaction using universal human V-region primers. The 845D3 Id probe detected the Id+ V region in the CSF of 14 of 31 MS patients, 1 of 9 patients with other neurologic diseases, and 1 of 10 non-neurologic patients. The gene product was more common in but not restricted to CSF with oligoclonal bands. The presence in CSF of MS patients of a cross-reactive Id to different MBP peptides is indicative of an immune response to this encephalitogenic myelin protein in a segment of MS patients. These findings are also evidence for limited usage of V-region Ig genes in the immune response of humans to MBP and the possible importance of an Id network for MBP in demyelinating disease.

Adult↗

Adelaide River virus nucleoprotein gene: analysis of phylogenetic relationships of ephemeroviruses and other rhabdoviruses.

The nucleotide sequence of the Adelaide River virus (ARV) genome was determined from the 3' terminus to the end of the nucleoprotein (N) gene. The 3' leader sequence comprises 50 nucleotides and shares a common terminal trinucleotide (3' UGC-), a conserved U-rich domain and a variable AU-rich domain with other animal rhabdoviruses. The N gene comprises 1355 nucleotides from the transcription start sequence (AACAGG) to the poly(A) sequence [CATG(A)7] and encodes a polypeptide of 429 amino acids. The N protein has a calculated molecular mass of 49429 Da and a pI of 5.4 and, like the bovine ephemeral fever virus (BEFV) N protein, features a highly acidic C-terminal domain. Analysis of amino acid sequence relationships between all available rhabdovirus N proteins indicated that ARV and BEFV are closely related viruses (48.3% similarity) which share higher sequence similarity to vesiculoviruses than to lyssaviruses. Phylogenetic trees based on a multiple sequence alignment of all available rhabdovirus N protein sequences demonstrated clustering of viruses according to genome organization, host range and established taxonomic relationships.

Amino Acid Sequence↗

Do schizophrenia and affective disorder share susceptibility genes?

Schizophrenia and affective disorders are relatively common neuropsychiatric diseases with a complex genetic etiology. A multigenic inheritance with variable influence of unknown environmental factors may be involved. Family studies have demonstrated the existence of both phenotypes in the same kindreds, and in certain cases, a transition from one phenotype to another occurs. In addition, intermediate phenotypes such as schizoaffective disorders are found in families with schizophrenia and affective illness. Recent genome and chromosomal scans appear to support these epidemiologic data, since susceptibility regions for both schizophrenia and affective disorders have been found to overlap, on chromosomes 10p13-p12, 13q32, 18p and 22q11-q13. These studies were performed in independently ascertained family samples with index patients afflicted either with schizophrenia or bipolar disorder. Taken together, these findings imply shared loci for schizophrenia and affective disorders among those required for the full expression of the phenotype. Identification and molecular characterization of the genetic components conferring risk to both disorders would impact positively on diagnosis, prevention, and treatment.

Bipolar Disorder↗

A new observation of acro-cardio-facial syndrome substantiates interindividual clinical variability.

We report on a baby presenting with ectrodactyly, heart defects, and mild facial dysmorphisms, an association recognized as acro-cardio-facial syndrome (ACFS). Based on the first three observations, the acronym CCGE, cleft palate, cardiac defect, genital anomalies, and ectrodactyly had been proposed to embrace the most consistent features of this syndrome. A subsequent report and the present patient point to an obvious interindividual and intrafamilial variability of this autosomal recessive disorder in which ectrodactyly was the sole characteristic shared by all affected individuals.

Abnormalities, Multiple↗

The protective effect of BCG vaccination of the newborn against childhood tuberculosis in an African community.

The latest controlled trial of BCG vaccination in southern India showed that two vaccines failed to confer protection against pulmonary tuberculosis. This result cast serious doubt on the effectiveness of BCG vaccination of the newborn, which is widely applied in developing countries. Therefore, WHO initiated a global research study to evaluate current programmes in developing countries. Part of this study was carried out in Lomé, Togo, in which child contacts of newly detected patients were followed up with clinical and radiological examinations. All observations were recorded according to a scoring system. Concomitant observations were made to verify the comparability of the vaccinated and unvaccinated children. Of the child contacts of 352 index cases, 1421 completed the examinations. The distribution of the final score made it possible to distinguish 175 children likely to suffer from tuberculosis: 113 among the 546 unvaccinated and 62 among the 875 vaccinated children. Significant incomparability was observed in respect of intensity of exposure: the vaccination coverage was relatively low, and the risk of disease relatively high, if a parent was the index case or the child shared the bedroom of the index case (which very often coincided). The other variables studied, including age and sex, turned out to be practically irrelevant as regards comparability. The estimate of the protective effect against all types of tuberculosis combined is 61.5%, which is slightly lower than suggested by the raw data (66%). The protective effect, however, appeared to increase considerably with severity of disease. In children of 5 years and older it was lower than in the younger children. Tuberculin testing failed to reveal any sensitivity induced by BCG in the vaccinated children. The distribution of the tuberculin reactions correlated poorly with the other diagnostic findings. Small reactions were only slightly more frequent in healthy than in sick children; only the very large reactions were associated with a higher risk of disease. This confirms that the tuberculin test is of very limited diagnostic value in young children.

BCG Vaccine↗

Biology of retroviruses: detection, molecular biology, and treatment of retroviral infection.

The general physical characteristics and replication of retroviruses are considered, along with assays for viral products. The specific agent for acquired immunodeficiency syndrome, the human immunodeficiency virus (HIV), is characterized as a lentivirus causing persistent, lifelong infection. While human immunodeficiency virus retroviruses share many of the same properties as other replication-competent viruses, genetic variability occurs among HIV isolates, and this variability may have a considerable effect on the virus' virulence, cell type specificity, viral susceptibility to antiviral compounds, clinical presentation, and disease progression. The most notable difference between HIV replication and other retroviruses is the intricate control of HIV gene expression by viral and cellular factors. Possible mechanisms by which HIV kills infected cells include the formulation of multinucleate syncytia; cytopathic components within the virions themselves; and interaction between viral envelope proteins and the CD4 molecule on the cell surface. Agents shown to inhibit viral replication at the level of the reverse transcriptase are phosphonoformate, sulfated polysaccharides, rifabutin, and nucleoside analogs, as well as purine and pyrimidine analogs. To date, only one nucleoside analog, zidovudine, has demonstrated clear clinical benefit and anti-HIV activity.

Acquired Immunodeficiency Syndrome↗

Decision making during serious illness: what role do patients really want to play?

Two surveys were conducted to determine what roles people actually want to assume in selecting cancer treatments. 436 newly diagnosed cancer patients and 482 members of the general public participated. Preferences were elicited using two card sort procedures, each of which described five potential roles in decision making. Findings suggested that the impact of being diagnosed with a life-threatening illness may influence preferences to participate. The majority (59%) of patients wanted physicians to make treatment decisions on their behalf, but 64% of the public thought they would want to select their own treatment if they developed cancer. Most patients (51%) and members of the public (46%) wanted their physician and family to share responsibility for decision making if they were too ill to participate. Sociodemographic variables accounted for only 15% of variance in preferences. These variables are not particularly useful in making predictions about which groups want more or less active roles in medical decision making.

Adult↗

Surface electromyographic studies of swallowing in normal subjects: a review of 440 adults. Report 3. Qualitative data.

OBJECTIVE: Surface electromyographic studies were performed on 440 normal adults to describe and evaluate different types of normal swallows clinically useful for ENT department. Study design Prospective observational study of healthy volunteers. METHODS: EMG recordings were made using stick-on surface electrodes. Rectified and filtered EMG signals were evaluated. Parameters evaluated include the graphic configuration of activity of the orbicularis oris, masseter, submental group, and infrahyoid muscles, the last 2 covered by platysma, during single swallowing and continuous drinking. Four tests were examined: voluntary saliva swallows, voluntary separate swallows as normal, voluntary separate swallows of excessive amount of water (20 mL), drinking of 100 mL of water. Graphic recording of activity of the above-mentioned muscles during swallowing and drinking were evaluated for groups of adults of different ages. RESULTS: There are several types of normal swallows as seen at the surface EMG records. There was no difference between EMG recordings of male and female swallows. Only group of elderly patients (age 70+) shows age-induced differences in recorded swallows. There are two main types of normal swallow: single-share and double-share swallows. The oral phase of swallowing, being under conscious control, is very variable and should not be taken into consideration during evaluation of records. Final oral, pharyngeal, and initial esophageal stages of swallowing can be defined and evaluated at the rectified and filtered surface EMG record. CONCLUSION: The normal muscle activity during swallows and drinking has several graphic patterns which can be identified and described similar to EKG records when surface EMG is rectified and filtered. The method of EMG recording is quick and simple, and can be used for screening and evaluation purposes in outpatient and inpatient ENT departments. These parameters represent activities required for normal deglutition, and can be used to identify abnormalities in ENT patients, and provide a basis for comparison of swallowing performance both within and between patients. These normal data form a valuable basis for future comparison with patients in pre- and postoperative stages and in EMG monitoring during ENT treatment.

Adolescent↗