SEARCH · PubMed Health

Results for “Generation mean analysis”

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 577 records · Page 32Linked to original sources

PubMed1996

Why sequence the genome of Mycobacterium tuberculosis?

Radical measures are required to prevent the grim predictions of the World Health Organisation for the deterioration of the global tuberculosis epidemic in the next century from becoming reality. Study of the nerve centre of the tubercle bacillus, its genome, by means of systematic deoxyribonucleic acid sequence analysis will provide a wealth of information about Mycobacterium tuberculosis that will undoubtedly fuel the next generation of research. In the coming year, this highly cost-effective approach will deliver an unprecedented amount of knowledge to catalyse the development of new, more efficient diagnostic tools and therapeutic interventions to detect, control and, ultimately, eliminate tuberculosis.

Animals↗

PubMed2002

Classification of oral clefts by affection site and laterality: a genotype-phenotype correlation study.

OBJECTIVES: The aim of this study was to classify the phenotypes found in a series of patients with non-syndromic cleft lip (CL) with or without cleft palate (CP) and isolated cleft palate. Additionally, the frequency distribution of cases belonging to families linked to markers on chromosomes 6 and 2 within these phenotypic patterns were estimated. DESIGN: A retrospective examination of all the available affected cases collected in Italy. SETTING AND SAMPLE POPULATION: Ninety-seven affected subjects aged 5-18 years belonging to 38 families were considered. Patterns were identified by variance of the cleft (lip, primary palate, secondary palate) and stratified according to the side of occurrence (right, left, or bilateral). Latent class analysis was used as main statistical tool for carrying out the results. RESULTS: Three homogenous classes were identified (P < 0.0001) by means of latent class analysis. Individuals were assigned to the most suited class. All three variables (lip, primary and secondary cleft palate) generated a specific class. Optimal findings were reported in cases having 'any isolated cleft lip' (class 1); 'secondary CP with or without bilateral/right primary cleft palate + bilateral/right cleft lip' (class 2); and 'left primary cleft palate + left/bilateral cleft lip with or without secondary CP' (class 3). Correspondence to the evidence of linkage to chromosome 6 showed that 9 of 10 cases presenting with 'right primary CP + right CL with secondary cleft palate' (class 2) belonged to a linked family. The same combination, but occurring on the left side (class 3), revealed that only three of nine cases belong to families linked to chromosome 6 (P-value = 0.02). The two patterns (right and left) never occurred in the same family. Three reliable groups were identified based on laterality and the presence of a cleft. A single right sided pattern displayed a statistically different distribution of linkage to chromosome 6 when compared with the homologous left side. CONCLUSION: Non-syndromic CL with/without CP can be classified according to laterality that can be under genetic control.

Adolescent↗

PubMed2000

Visually-guided irrigation in patients with early knee osteoarthritis: a multicenter randomized, controlled trial.

OBJECTIVE: To determine if visually-guided arthroscopic irrigation is an effective therapeutic intervention in patients with early knee osteoarthritis. DESIGN: Ninety patients with knee osteoarthritis were randomized in a double-blind fashion to receive either arthroscopic irrigation with 3000 ml of saline (treatment group) or the minimal amount of irrigation (250 ml) required to perform arthroscopy (placebo group). The primary outcome variable was aggregate WOMAC score. RESULTS: The study did not demonstrate an effect of irrigation on arthritis severity as measured by aggregate WOMAC scores, the primary outcome variable; the mean change in aggregate WOMAC score at 12 months was 15.5 (95% CI 7.7, 23.4) for the full irrigation group compared to 8.9 (95% CI 4.9, 13.0) for the minimal irrigation group (P=0.10). Full irrigation did have a statistically significant effect on patients' self-reported pain as measured by the WOMAC pain subscale and by a visual analog scale (VAS) (the secondary outcome variables). Mean change in WOMAC pain scores decreased by 4.2 (95% CI -0.9, 9.4) for the full irrigation group compared with a mean decrease of 2.3 (95% CI -0.1, 4.7) in the minimal irrigation group (P=0.04). Mean VAS pain scores decreased by 1.47 (95% CI -1.2, 4.1) in the full irrigation group compared to a mean decrease of 0.12 (95% CI 0.0, 0.3) in the minimal irrigation group (P=0.02). A hypothesis-generating post-hoc analysis of the effect of positively birefrigent intraarticular crystals showed that patients with and without intraarticular crystals had statistically significant improvements in pain assessments and aggregate WOMAC scores at 12 months; patients with crystals had statistically greater improvements in pain. CONCLUSIONS: Visually-guided arthroscopic irrigation may be a useful therapeutic option for relief of pain in a subset of patients with knee OA, particularly in those who have occult intraarticular crystals.

Adult↗

PubMed1970

The reductive inactivation of UDPgalactose-4-epimerase from yeast and E. coli.

The prosthetic groups of UDPgalactose-4-epimerase from yeast and E. coli can be reduced by incubation with D-galactose or L-arabinose provided that 5' uridylic acid (5'UMP) is also present. This type of concerted reduction can also be performed using sodium borohydride. The latter type of reduction also depends on the addition of 5'UMP. Enzymatic analysis of the released prosthetic group by means of lactic dehydrogenase and pyruvate revealed that the pyridine nucleotide of the reduced epimerase generated in the concerted reaction is dehydrogenated in the 4-position of the pyridine ring. The catalytic activity of the reduced epimerase is much lower than that of epimerase (10-15% of native epimerase). This reductive inactivation was also found in crude epimerase preparations from E. coli, again provided 5'UMP is present. Fractionated E. coli epimerase subjected to the concerted reduction show a striking fluorescent enhancement of the order of magnitude of that observed in the purified yeast epimerase. Unlike the latter, however, E. coli epimerase also becomes fluorescent upon addition of the specific substrate UDPgalactose. The physiological aspects of the phenomenon as related to induction of the galactose genes is discussed.

Arabinose↗

PubMed1987

Aging can be genetically dissected into component processes using long-lived lines of Caenorhabditis elegans.

The aging process has been dissected by analysis of genetic variants of the nematode Caenorhabditis elegans. Long-lived recombinant inbred lines were generated; some of these lines have mean and maximum life spans up to 70% longer than wild type. Longer life results from a slowing of the characteristic exponential increase in mortality rate that is typical of aging populations in all species. The length of developmental periods and the length of the reproductive period are unrelated to increased life span. Lengthened life is due entirely to an increase in postreproductive life span. Development, reproduction, and life span are each under independent genetic control. General motor activity decays linearly with chronological age in all genotypes. The decay in general motor activity is correlated with and a predictor of life span, suggesting that both share at least one common rate-determining component.

Aging↗

PubMed1981

Food eating patterns and health: a reexamination of the Ten-State and HANES I surveys.

Dietary, clinical, and biochemical data from the Ten-State Nutrition Survey (1968 to 1970) and the Health and Nutrition Examination Survey I (1971 to 1974), have been reexamined by factor analysis to focus attention on eating patterns as a means of relating food intake to health. The seven statistically different eating patterns generated were characterized by disproportionate consumption of different food groups. The relationship between the combination of foods that people ate and the state of their nutritional health was examined for both samples in total, and for various age, sex, race, region, and income groups within the Health and Nutrition Examination Survey I sample. Significantly different associations between the seven eating patterns and the absence of clinical symptoms and biochemical deficiencies were found. Some eating patterns consistently stood out as being significantly better or worse in this regard (p less than 0.05). This food eating pattern model should prove useful for 1) examining the association between food consumption and the incidence of disease states, such as obesity, hypertension, cardiovascular disease, cancer, and periodontal disease for various large scale dietary-health surveys, 2) establishing food regulatory policies, 3) setting national dietary goals, and 4) educating the public on nutrition and health issues.

Adolescent↗

PubMedDate not supplied

How elderly nursing home residents transcend losses of later life.

Losses of later life can prove overwhelming to older adults. Some elderly persons seem to cope with these losses with a spirit of acceptance and serenity. The purpose of this study was to identify qualities in selected nursing home residents that allow them to transcend difficulties and continue living with some degree of contentment and satisfaction. Qualitative data were obtained in taped interviews from 95 functionally impaired residents (mean age 82.16 years). Content analysis resulted in several themes supporting the spiritual perspective of Reed's theory of self-transcendence: generativity, introjectivity, temporal integration, body-transcendence, and relationship with self, others, and a higher being.

Activities of Daily Living↗

PubMed1992

Diagnosis of typhus infection with Rickettsia tsutsugamushi by polymerase chain reaction.

Two sets of oligonucleotide primers were used to amplify the genomic DNA of Rickettsia tsutsugamushi, the causative agent of scrub typhus (tsutsugamushi disease), by the polymerase chain reaction. Each set of primers amplified 538-bp and 109-bp products, representing part of a gene encoding a possible major 58-kDa immunogenic protein, from whole genomic DNA extracted from R. tsutsugamushi strains Karp, Kato, Gilliam, Kuroki and Kawasaki. No amplification was observed from R. sibirica, R. rickettsii, mouse and human genomic DNA. DNA amplification was observed from crude lysates of peripheral whole blood, tissue homogenates and paraffin-embedded skin biopsy sections obtained from patients with scrub typhus disease. Southern blot analysis demonstrated the specificity of the amplified DNA fragments following hybridisation with a DNA probe generated from R. tsutsugamushi strain Karp. By means of this procedure, a rapid and sensitive diagnosis of scrub typhus disease can be made during the acute stage of this infection.

Acute Disease↗

PubMed1998

Clinical and genetic studies of spinocerebellar ataxia type 2 in Japanese kindreds.

OBJECTIVES: We report the results of clinical and genetic studies from 2 related Japanese kindreds with spinocerebellar ataxia type 2 (SCA2). MATERIAL AND METHODS: Family A showed 19 patients through 4 generations, while family B showed 6 patients, including dizygotic twin brothers, through 3 generations. We performed clinical, radiological, neurophysiological, and genetic analyses in the family members. RESULTS: Neurologic analysis of 13 affected patients revealed a mean age at onset of 43.5 years. The most common neurologic finding was cerebellar ataxia with deep sensory disturbance. Slow saccades was found only in the younger patients below age 35 years. Nerve conduction studies revealed subclinical sensory neuropathy. Brain MRI showed the presence of pontocerebellar atrophy. Genetic study using PCR revealed that all affected patients had an expanded CAG allele in the ataxin-2 gene, which led to a final diagnosis of SCA2. CONCLUSION: SCA2 may be more clinically heterogeneous than previously thought. PCR is useful in differentiating SCA2 from other types of inherited ataxia.

Adult↗

PubMed1994

Increasing melanoma incidence: putatively explainable by retrotransposons. Experimental contributions of the xiphophorine Gordon-Kosswig melanoma system.

The worldwide accelerating increase of neoplasia in humans is difficult to explain. We use the Xiphophorus tumor model to approach this problem by melanoma provocation with X-rays. Melanoma develops following inappropriate expression of x-erb B-conducted developmental genes and their controllers. These oncodeterminants are inherited according to Mendelian rules. We detected a new type of oncodeterminants that, following a single treatment of embryos with X-rays, generates a self-generating non-Mendelian melanoma transmission and accelerating increase of its incidence in succeeding generations (e.g., 0-->18-->33-->52%). To localize these oncodeterminants, we crossed nonirradiated fish having half of their chromosomes irradiated with nonirradiated fish having none of, half of, or all of their chromosomes irradiated. Because tumor rate and expression in the following generations correspond to the rates of treated chromosomes, we conclude that the new oncodeterminants are distributed over the chromosomes of the fish, where they may increase in the changing generations. By means of xiphophorine-specific retroviral DNA, we isolated two retrotransposons that behave hereditarily like the new transgenerational oncodeterminants. Sequence analysis revealed three ORFs flanked by LTRs containing motives of regulatory sequences typical for known retroviral and retrotransposal LTRs. Pol- and env-resembling sequences are lacking. Southern and in situ hybridization showed their multiple and repetitive nature distributed throughout the chromosomes and indications for their capability to increase in number without further treatment. Their transcripts are expressed in concert with those of most of the other known xiphophorine tumor determinants. Their expression is extremely high in cell cultures from tumorous embryos derived from ancestors treated as embryos with X-rays.

Animals↗

PubMed1985

Discrimination between precancerous and cancerous lesions of the uterine cervix by DNA measurements on tissue sections.

Morphologically typical uterine cervical biopsies were separated into normal cervices, condylomas and cervical intraepithelial neoplasias (CIN) grades I, II and III. At least 100 nuclei per lesion were measured on 4 micron Feulgen-stained sections using a Zeiss microspectrophotometer, with a variant of the plug method used to compute the nuclear DNA content. DNA distribution histograms were then decomposed into subsets of diploid, tetraploid, octoploid and aneuploid cells. The decomposition, which assumed a log-normal model of polydiploidy distribution, led to the identification of six indices: (1) the percentage of diploid cells, (2) the percentage of tetraploid cells, (3) the percentage of octoploid cells, (4) the percentage of aneuploid cells with DNA contents less than tetraploidy, (5) the percentage of aneuploid cells with DNA contents between tetraploidy and octaploidy and (6) the percentage of aneuploid cells with DNA contents greater than octoploidy. These indices, along with the mean nuclear radius, the 5c exceeding rate and the 2c deviation index, generated a nine-dimensional space. Two methods of discriminant analysis on this space showed discriminating powers of 78.22% and 87.13%, respectively, as compared to the original diagnoses. The most discriminating variable in both analyses appeared to be the percentage of octoploid cells.

Biopsy↗

PubMed1995

[Effect of acid aspiration on right lymph duct lymph flow and prostaglandin metabolites in dogs].

Aspiration of acid gastric contents into the airways is a major cause of pulmonary injury. The author investigated the effects of intratracheal instillation of hydrochloric acid in the anesthetized dogs on pulmonary hemodynamics, pulmonary lymph flow and protein content, and stable metabolites of prostaglandin F2 alpha (PGF2 alpha), prostacyclin (PGI2) and thromboxane A2 (TXA2). The author measured the concentrations of 15-keto-13, 14-H2-PGF2 alpha, 6-keto-PGF1 alpha and TXB2 in blood and pulmonary (right duct) lymph by specific radioimmunoassay. After intratracheal instillation of 0.1 N HCL, 3 ml.kg-1, the right duct lymph flow increased significantly from 1.3 to 4.5 ml.h-1, and pulmonary lymph-to-plasma protein ratio increased significantly from 0.63 to 0.70. There was no significant change in hemodynamics after acid instillation. There was no significant change in arterial or mixed-venous blood levels of any of the three metabolites. After acid instillation, the right duct lymph concentrations increased 2-fold for PGI2 metabolite, 3-fold for TXB2, and 7-fold for PGF2 alpha metabolite. The flow of metabolites (concentration x flow) increased 13-fold for 6-keto-PGF1 alpha, 14-fold for TXB2, and 40-fold for PGF1 alpha metabolite. The author concludes that intratracheal instillation of hydrochloric acid in anesthetized dogs: 1) increases pulmonary microvascular permeability, and 2) stimulates the pulmonary generation of PGF2 alpha, prostacyclin and thromboxane, and that 3) the analysis of pulmonary lymph flow and its constituents is a useful means for the study of lung injuries.

Anesthesia, Intravenous↗

PubMed1996

Retinal blood flow changes in type I diabetes. A long-term follow-up study.

PURPOSE: The authors previously reported that blood speeds in the retinal arteries were significantly lower in patients with type I diabetes than in controls without diabetes. The purpose of this long-term, follow-up study was to characterize the natural course of changes in blood speed and blood flow in these patients. METHODS: Twenty-four patients were followed up with serial annual measurements of the blood flow in a temporal retinal artery using the bidirectional laser Doppler technique and monochromatic photography. The follow-up period ranged from 2 to 6 years (mean, 3.8 years). Using standardized color fundus photography and fluorescein angiography, a retinopathy score was generated for each eye studied. Linear regression analysis was used to compute the slope of the change in retinal blood flow for each patient during the follow-up period. RESULTS: Retinal blood flow slopes were negative in 15 patients and positive in 9 patients. Multiple linear regression analysis showed that the retinal blood flow slopes were significantly related to the retinal blood flow measured at entry to the study and to the median duration of diabetes during the follow-up period (R2 = 0.56; P = 0.0002). There was a positive correlation between the retinal blood flow slopes and the median retinopathy score during the follow-up period (P = 0.47; P = 0.02). CONCLUSIONS: As duration of diabetes becomes longer and retinopathy becomes more severe, there is a transition from negative to positive retinal blood flow slopes. This bimodal relationship between the change in retinal blood flow and the duration of diabetes reflects the complex pathologic alterations that occur in the diabetic retina.

Adult↗

PubMed1995

U83836E reduces secondary brain injury in a rabbit model of cryogenic trauma.

Oxygen-derived free radicals have been implicated in secondary brain injury after head trauma. Although oxygen-free radicals may be derived from multiple sources, the activation and accumulation of neutrophils in areas of brain injury is a potential source of deleterious inflammatory mediators, including free radicals, which may exacerbate the primary insult. Neutrophils may also impede the cerebral microcirculation by congestion and occlusion of postcapillary venules. The lazaroid U83836E is a potent-free radical scavenger that inhibits lipid peroxidation. U83836E was studied in a cryogenic model of cerebral injury in pretreatment paradigm. Fifteen rabbits received a unilateral cryogenic brain lesion. Six animals received U83836E, and nine animals received vehicle only. Arterial blood gases, hematocrit, temperature, and mean arterial pressure were controlled in physiologic range throughout the experiment. Intracranial pressure was continuously monitored. Lesion size was determined by triphenyltertrazolium chloride staining and planimetric image analysis. Neutrophil aggregation and oxygen-free radical generation was assessed in whole blood by impedance aggregometry and simultaneous luminol-mediated chemiluminescence, respectively. Myeloperoxidase assay was used to determine neutrophil accumulation within the brain. Elevations in intracranial pressure from baseline values were significantly greater in the untreated (control) animals at all time points (p < 0.0001). Mean lesion size (% hemisphere +/- SEM) was significantly reduced in animals receiving U83836E (4.41 +/- 0.64, n = 6) when compared with controls (15.09 +/- 2.28, n = 9, p < 0.001). A reduction in both the release of oxygen-free radicals and in neutrophil aggregation following the cryogenic injury in the U83836E animals correlated with a smaller lesion volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2000

Maximum force production: why are crabs so strong?

Durophagous crabs successfully hunt hard-shelled prey by subjecting them to extremely strong biting forces using their claws. Here I show that, for a given body mass, six species of Cancer crabs (Cancer antennarius, Cancer branneri, Cancer gracilis, Cancer magister, Cancer oregonensis and Cancer productus) were able to exert mean maximum biting forces greater than the forces exerted in any other activity by most other animals. These strong biting forces were in part a result of the high stresses (740-1350 kN m(-2)) generated by the claw closer muscle. Furthermore, the maximum muscle stress increased with increasing mean resting sarcomere length (10-18 microm) for the closer muscle of the claws of these six Cancer species. A more extensive analysis incorporating published data on muscle stresses in other animal groups revealed that stress scales isometrically with the resting sarcomere length among species, as predicted by the sliding filament model of muscle contraction. Therefore, muscle or filament traits other than a very long mean sarcomere length need not be invoked in explaining the high stresses generated by crustacean claws.

Animals↗

PubMed2006

Effect of copper exposure on gene expression profiles in Chlamydomonas reinhardtii based on microarray analysis.

Copper is a naturally occurring trace metal with toxic properties for man and environment. It is assumed that toxicity is primarily caused by oxidative damage, generated through the production of reactive oxygen species. Copper is, however, also an essential element, which means trace amounts are necessary for biological processes to function properly. Organisms are therefore presented with the challenging problem of maintaining copper concentrations within a well-defined range to avoid stress. We exposed the green alga Chlamydomonas reinhardtii to different copper concentrations and used microarray analysis to investigate the changes in mRNA abundances and to obtain an image of the molecular mechanisms underlying copper homeostasis. The results confirm and extend upon previous findings showing that in the case of lower copper concentrations there is a change in levels of mRNA coding for alternative polypeptides which can take over the function of certain copper containing molecules so as to compensate for the lack of copper. In the case of copper toxicity, there is a strong upregulation of transcripts encoding enzymes involved in oxidative stress defense mechanisms. In both cases, there were significant changes in expression levels of transcripts coding for enzymes involved in several metabolic pathways (photosynthesis, pentose phosphate pathway, glycolysis, gluconeogenesis), in general stress response (heat shock proteins) and in intracellular proteolysis (lysosomal enzymes, proteasome components).

Algal Proteins↗

PubMedDate not supplied

Fast wavelength scanning reflectance spectrophotometer for noninvasive determination of hemoglobin oxygenation in human skin.

Oxygen saturation of hemoglobin (HbSO2) in skin vessels may be determined with photometric methods. However, the optical complexity of the skin makes quantitative measurements difficult. A possible approach is the analysis of reflectance spectra using the two-flux theory of Kubelka and Munk. The final equation of this theory which describes the transformation between absorbed and reflected light has been approximated by a hyperbola. Based on this approximation we evaluated skin spectra obtained from the forearm of 23 healthy subjects with a fast scanning reflection photometer (Oxyscan) applying visible light (535-620 nm). The hyperbola was used in a multicomponent analysis in which the measured spectrum is recalculated using reference spectra of oxygenated and deoxygenated hemoglobin (gaussian least-square method). A crucial requirement for the evaluation is the subtraction of the individual skin spectrum, obtained by clearing a spot of skin of hemoglobin exerting external pressure. At rest HbSO2 was in the range between 42 and 89% (mean +/- SD: 72.9 +/- 12.2%). Pharmacological and thermal generation of hyperemia combined with respiration of pure oxygen raised the values to 86-100% (97.9 +/- 4.6%). This was in good agreement with capillary ex vivo analysis yielding 96-100% (98.7 +/- 0.4%). Under arterial occlusion HbSO2 fell below 30% (14.5 +/- 7.8%). Our method allows rapid determinations of absolute HbSO2 values in the skin. The evaluation error is estimated to be between 5% for oxygenated and 10% for deoxygenated values.

Arterial Occlusive Diseases↗

PubMed2006

The cochlear-carotid interval: anatomic variation and potential clinical implications.

BACKGROUND AND PURPOSE: A temporal bone CT study in a patient with episodic mid-tone sensorineural hearing loss and tinnitus demonstrated absence of bone between the petrous internal carotid artery and the basal turn of the cochlea. The potential implications with respect to increasingly popular cochlear implant surgery compelled us to retrospectively analyze a series of temporal bone CT scans to establish typical measurements for this region, which we termed the "cochlear-carotid interval" (CCI). METHODS: After IRB exemption, 2 observers independently measured the bony interval between the cochlea and the petrous internal carotid artery canal on coronal images from 30 consecutive temporal bone CT studies. The 1-mm thick coronal images were either acquired directly or were reconstructed from an axial dataset acquired at 0.75 or 0.6 mm section thickness. All measurements were performed by using electronic calipers on a Sienet MagicView VE 42 Siemens PACS station. Mixed model analysis of variance was used to evaluate differences between readers and sides with respect to the mean CCI but adjusted for age and accommodating the correlation among observations generated for the same subject. RESULTS: The patient in our case report had a right CCI of 0.2 mm and left CCI of 0.0 mm. In the other 30 patients, the right CCI ranged from 0.2 to 3.8 mm (mean, 1.2 +/- 0.8 mm; median, 0.9) and the left CCI from 0.2 to 5.0 mm (mean, 1.1 +/- 0.9 mm; median, 0.8). The CCI did not exhibit a significant association with subject age (P = .1336), and there were no significant differences between readers (P = .824) or sides (P = .350) in terms of mean CCI. CONCLUSION: The CCI varies widely between patients and may be as small as zero. Analysis of anatomic relationships suggests a potential relationship between small CCI and mid-tone sensorineural hearing loss, as in our reported patient. Preoperative knowledge of thin or absent bone between the cochlea and petrous carotid canal may help prevent inadvertent penetration of the carotid canal during cochlear implant surgery.

Adolescent↗