SEARCH · Search PubMed

Results for “differential selection”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

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

At least 937 records · Page 52Linked to original sources

PubMed1987

[Effect of the climate of the Anapa health resort on the effectiveness of treatment of chronic aspecific lung diseases in adolescents].

The results of examination of 2144 adolescents with bronchial asthma and chronic bronchitis coming to the health resort area of the Black Sea coast of the Caucasus from various regions of the USSR showed a significant effect of the climatic and weather factors on the efficacy of sanatorium treatment. Change of climatic zones resulted in the reduction of therapeutic efficacy due to dysadaptation reactions of the body necessitating stricter indications for a differentiated selection of adolescents coming from contrast climatic zones of the Urals, Siberia and the Far East.

Adolescent↗

PubMed1979

Differential inhibition of host and viral thymidylate synthetases by folylpolyglutamates.

The ability of folate analogues to inhibit host and viral thymidylate synthetases was measured using the corresponding Escherichia coli and T2-phage-induced enzymes. In the absence of Mg2+, 6 x 10(-7) M pteroylhexaglutamate inhibited the T2-phage-induced synthetase by 50%, but at least 100-fold greater levels of this compound were necessary to inhibit the E. coli synthetase by this amount. At 2.5 x 10(-6) M pteroylhexaglutamate, at least 80% inhibition of the T2-phage synthetase could be obtained with little or no inhibition of the E. coli enzyme. The pteroylmonoglutamate was about 2 orders of magnitude less inhibitory towards the T2-phage enzyme than the pteroyltri- to -heptaglutamates. However, upon addition of Mg2+ to the assay mixture, the inhibition produced by pteroylhexaglutamate was essentially reversed, with the E. coli synthetase now increasingly inhibited by this compound and the T2-synthetase only minimally impaired. Methotrexate and N10-formyl-2-amino-4-hydroxyquinazoline, although inhibitory to both enzymes in the presence or absence of Mg2+, did not show this differential selectivity. These results suggest that certain folate analogues may be useful in distinguishing between a host and an infecting organism's thymidylate synthetase and could thus provide an additional means of screening for potential chemotherapeutic agents.

Coliphages↗

PubMedDate not supplied

Medical applications of fiberoptic sensors.

The key requirements of receptor biomolecules for use in affinity optodes are 1) totally reversible binding, 2) rapid equilibration (on the order of minutes or less), 3) no destruction of the analyte or competing analyte, 4) high differential selectivity (binding constants) for analytes of similar structures, and 5) long-term stability. An obvious first choice for sources of receptors for biosensors is antibodies; these immunoproteins are easily derived for drugs, metabolites, and hormones. However, most of the antibodies selected for immunoassay purposes have very high binding constants for their analytes, which may be the result of very slow dissociation rates. Thus, antibodies to be used in biosensors should be screened for high dissociation rates. Monoclonal antibodies appear to be the most suitable from this point of view.

Antibodies, Monoclonal↗

PubMed1981

[Applications of the peroxidase-anti-peroxidase technique in dermatology (author's transl)].

The immunohistological findings are reported in 62 cases of malignant lymphomas, pseudolymphomas and malignant histiocytic disorders of the skin. Paraffin-embedded tissue was analyzed with the Peroxidase-Antiperoxidase (PAP) Technique for the presence of intracytoplasmic immunoglobulin (IgM, IgA, IgG, Kappa, Lambda) ana lysozyme. It can be stated that the PAP technique appears to be a valuable aid in interpreting and differentiating selected material of cutaneous lymphoproliferative and histiocytic disorders. The method supplements routine histological and histochemical staining procedures.

Histiocytoma, Benign Fibrous↗

PubMed1984

Establishment and characterization of human colorectal cancer cell lines.

A protocol for establishment of human colorectal carcinoma cell lines from fresh surgically removed tissues is described. Twelve human colorectal carcinoma cell lines were established from 6 of 18 primary cancers and four of four metastases. Cell lines from concurrent primary tumors and metastases were established from two individual patients. Two primary cancers gave rise to multiple cell lines with differing biological characteristics. Factors contributing to our success appear to be differential selection on the basis of substrate adherence and the timing of passage. The protocol avoids the use of feeder layers or passage through athymic mice. The established cell lines exhibit a range of karyotypes, morphologies, and growth characteristics.

Biopsy↗

PubMed1983

[Inversion polymorphism of the malarial mosquito Anopheles messeae. V. The interaction of different chromosomal inversions in the spatial area].

The relations between inversions of chromosome XL, 2R, 3R, 3L from 8 populations of the central part and periphery of the species area were studied. 2-, 3- and 4-factor analysis was carried out. Interaction of inversions XL1, 2R1, 3R1 in central populations (Riga, Moscow, Tomsk) was observed. The nonrandom association of definite inversional genotypes was stationary in spatial - temporary. The phylogenetic initial sequences XL0, 2R0, 3R0 display "+" interaction. The 3-factor analysis of populations of Tomsk shows: 1) interaction of inversions is more essential in males than in females; 2) the statistically significant interaction of 3-4 inversions is not always determined by the effect of 2-factor analysis; 3) the chromosome 3R has a dominance influence on the pattern of association of the multiinversional complex. These data support the hypothesis that differential selection for chromosomes with certain combinations of arrangements is mainly responsible for this phenomenon. In peripheral area populations (Syctyvkar, Irkutsk, Chita), no associations were observed (2R and 3R). When they do take place, their character is changed (Kiev - XL and 3R). This phenomenon may be explained by the influence of frequency-dependent selection.

Animals↗

PubMed1984

[Echographic study of the structure of a malignant melanoma of the choroid].

The case of a 74 yr. old male affected by a mixed cell choroidal melanoma is reported. Ophthalmoscopic examination suggested a choroidal melanoma; this diagnosis was confirmed by fluorescein angiography, ultrasonography and CT-scan. In particular, contact ultrasonography (A-mode and B-mode), following topographic, kinetic and quantitative diagnostic criteria, revealed a solid lesion with the typical features of a choroidal melanoma. Ultrasonography by differential selective echographic technique revealed that the lesion consisted of two components with different acoustic features : the first characterized by a 41 dB reflectivity (peripheral and superior portions), the second by a 23 dB reflectivity (central and inferior portions). Attenuation values were 1.2 dB/mm and 0.7 dB/mm, respectively. CT-scan did not show any significant change in density within the mass. Histopathologic evaluation confirmed a clear-cut edge between the epitheloid and the spindle-cell components. The more reflecting lesion (23 dB), located in the central-inferior portion of the lesion, was histologically less dense and was due to the epitheloid component. The superiorally located more attenuating lesion (1.2 dB/mm) was histologically more dense and due to the spindle-cell component.

Aged↗

PubMed1983

Pathways of Xenopus optic fibres regenerating from normal and compound eyes under various conditions.

We have used Horseradish peroxidase to investigate the pathways taken by Xenopus optic fibres regenerating from normal and electrophysiologically-confirmed compound eyes to the optic tectum. Optic fibres, when sectioned near the chiasma, regenerate up both sides of the diencephalon to both tecta. We have therefore been able, by using animals in which one eye had or had not been removed at early embryonic stages, to look at the behaviour of regenerating axons in three different situations: (1) regeneration to the contralateral tectum, previously innervated by the sectioned fibres; (2) regeneration to a "virgin' ipsilateral tectum, never before innervated by optic fibres; and (3) regeneration to an ipsilateral tectum already innervated by fibres from a normal eye. From the chiasma to the tectodiencephalic junction regenerating fibres behave similarly in all three situations, following roughly the course of the normal optic tract, but running in a rather disorganised way, with frequent crossing over of fibres. However fibres of nasal retinal origin (from an NN eye) spread to occupy a much larger area of the side of the diencephalon than those of temporal origin (from a TT eye). From the tectodiencephalic junction to the tectal termination of the fibres there are differences between the three situations investigated; fibres regenerating to a 'virgin' ipsilateral, or to a denervated contralateral tectum, tend to grow straight onto the tectum, instead of being channelled into lateral or medial brachium as uncut fibres tend to be. There is however, the remains of a brachial organisation, and of differential selection of these brachia by fibres from the different types of compound eye, this being well seen on "virgin' tecta. Fibres regenerating to an ipsilateral innervated tectum behave very differently. As they reach the tectodiencephalic junction they suddenly start to grow in a less disorganised way, and are channelled into well defined brachia. If from a compound eye, these fibres terminate on only that part of the tectum innervated by fibres from the corresponding part of the normal eye. Thus fibres from a VV eye and those from the ventral half of the normal eye all terminate on medial tectum; fibres from an NN eye, and those from the nasal half of the normal eye all terminate in caudal tectum; and temporal fibres from both normal and TT eyes terminate in rostral tectum.

Animals↗

PubMedDate not supplied

[Comparison of the MPN method and direct counting on specific selective media for bacteriological examination of surface and waste waters].

A tentative procedure, with solid plated selective-differential media, for enumeration of total and fecal coliforms and enterococci in surface and waste waters is described. Results obtained with such techniques appear to be satisfactory in comparison with the traditional official procedure (MPN) for fecal coliforms (E. coli). The procedure and cultural media proposed is not satisfactory for total coliforms counting and it is only partially satisfactory for enterococci direct enumeration. We then propose the direct enumeration technique on mFC agar for fecal coliforms estimation. Further experiments for improving counting procedures for the other microbiological parameters are in progress.

Enterobacteriaceae↗

PubMed1980

[Cardiotocographic diagnosis in pregnancy (author's transl)].

A diagnostic programme has been recommended for cardiotocography in pregnancy. It is designed to non-stress testing and includes the oxytocin exposure test for better assessment of both oscillations and accelerations, depending on foetal movement, without or following arousal stimulus. -- Up to 95 per cent of all findings are obtained from non-stress or negative oxytocin exposure tests which are highly dependable diagnostic indicators to sufficient oxygen supply to the foetus. A pathological oxytocin exposure result would call for differentiated selection of those frequency images which do support suspicion of hypoxia, but these account only to something between two and five per cent among all high-risk pregnancies under conditions of selective cardiotocography.

Female↗

PubMed1981

[Clinical variants of the recovery period in myocardial infarct and their importance in patient rehabilitation].

During one year 279 patients were observed after myocardial infarction while working. Four clinical variants during the restorative period with concrete symptomatics have been isolated: the congestive cardiac insufficiency, angina pectoris, neurotic and with few symptoms. These symptoms can serve to differentiate selection of treatment and also to help the physician in selecting rehabilitation and to offer opinion as to prognosis.

Adult↗

PubMed1978

Sources of Salmonellae in broiler chickens in Ontario.

Sources of Salmonellae infecting broiler chicken flocks in Ontario were investigated from July, 1975 to April, 1976. Three broiler flocks were investigated on each of four farms which received chicks from a common hatchery. Samples of feed and new litter were preenriched in nonselective broth subcultured to Salmonella-selective enrichment broth and plated on Salmonella-selective differential agar. Samples of used litter, water, culled chicks, insects, mice, wild birds and environmental swabs were not cultured initially in the nonselective broth. Fecal samples from principal and occasional flock attendants were examined for Samonellae. Salmonella infection, as judged by contaminated flock litter was detected in six flocks on two of the farms while the flocks on the other farms remained negative. Salmonellae were isolated from 23 of 412 feed samples (nine serotypes), six of 35 new wood shaving samples (four serotypes), one of 29 pools of culled chick viscera (one serotype) and 44 of 267 used litter samples (14 serotypes). These results indicate that broiler chicken flocks were infected with diverse Salmonellae introduced in day old chicks, pelleted feeds, wood shavings and residual contamination from the preceding flock.

Animal Feed↗

PubMed1980

[Hypertension and surgical risk].

The perioperative risk of the patients with hypertension improves when the antihypertensive therapy is continued to the date of operation and a differentiated selection of narcotics and narcosis adjuvants as well as a careful narcotization is performed. In these cases the continuous control of the patient is necessary. In case of an operative intervention hypertension must be reason for the interdisciplinary cooperation between internist, surgeon and anaesthesiologist.

Anesthesia, General↗

PubMed1994

Polymerase chain reaction (PCR) as a diagnostic tool in HIV infection.

We set up a PCR laboratory for the diagnosis of HIV-1. Probably due to the variability of the HIV-genome, classical primers that performed well in some laboratories in the past, did not suffice for detection of HIV-1 strains in Belgian hospitals. Two new primer sets amplifying a fragment in the LTR-gag gene and in the env gene, which perform better on strains seen in Belgium, have been developed and evaluated. One primer set, conceived and evaluated on Belgian strains by the "Instituut voor Tropische Geneeskunde" in Antwerp, was also included. These three primer sets performed superior (92% sensitivity and 100% specificity on 24 samples) than the classical primers (83.5% sensitivity and 56% specificity on 21 samples). Together with a well-studied testing algorithm, they allow the reliable identification of the presence of the HIV-1 genome. To detect resistance of HIV-1 to reverse transcriptase (RT) inhibitors, we developed a set of two overlapping nested PCR primer sets and additional sequencing primers to amplify and sequence the total RNA or DNA RT gene using a direct cycle sequencing approach of the amplified fragment. Some clinical isolates were amplified and sequenced. In HIV-1 isolates from TIBO R82913-treated patients we identified two amino acid mutations (V108I and Y188L) involved in resistance (more than 100-fold reduced sensitivity). In an untreated patient we identified an amino acid variant (I/V 179D) involved in a 7-fold reduced sensitivity to TIBO. Several other amino acid variants, not involved in resistance, were detected in treated and untreated patients. Using this sequencing technique on cultured virus isolates we also observed in one TIBO-treated patient a differential selection among the strains of the original HIV-1 pool. From this patient we isolated and sequenced a completely TIBO sensitive HIV-1 strain after extensive cultivation in cord blood lymphocytes of the original TIBO resistant HIV-1 virus pool. We could however identify the resistant genotype after cultivation of this resistant HIV-1 virus pool on CEM cells. Our study revealed that sequencing investigations on emerging resistance should preferentially be done with uncultured patient samples since viral sequences and virus-drug sensitivities obtained from isolates cultured in vitro may not necessarily correspond to the sequences and sensitivities of the dominant strain in vivo.

Amino Acid Sequence↗

PubMed1995

Ubiquitin and the enigma of intracellular protein degradation.

Contrary to widespread belief, the regulation and mechanism of degradation for the mass of intracellular proteins (i.e. differential, selective protein turnover) in vertebrate tissues is still a major biological enigma. There is no evidence for the conclusion that ubiquitin plays any role in these processes. The primary function of the ubiquitin-dependent protein degradation pathway appears to lie in the removal of abnormal, misfolded, denatured or foreign proteins in some eukaryotic cells. ATP/ubiquitin-dependent proteolysis probably also plays a role in the degradation of some so-called 'short-lived' proteins. Evidence obtained from the covalent modification of such natural substrates as calmodulin, histones (H2A, H2B) and some cell membrane receptors with ubiquitin indicates that the reversible interconversion of proteins with ubiquitin followed by concomitant functional changes may be of prime importance.

Animals↗

PubMed1993

Expression of beta 1 integrins in sensory neurons of the dorsal root ganglion and their functions in neurite outgrowth on two laminin isoforms.

Integrins are heterodimeric receptors that mediate responses of neurons and many other cell types to components of the extracellular matrix. In the present article, we examine the roles of individual integrin receptors expressed by spinal sensory neurons of the dorsal root ganglion (DRG) in mediating interactions with laminin, an extracellular matrix glycoprotein that promotes neurite outgrowth. DRG neurons were shown to express three beta 1 integrins that have been shown in other cell types to function as laminin receptors--high levels of alpha 1 beta 1 and alpha 3 beta 1 and low levels of alpha 6 beta 1. In addition, DRG neurons were shown to express a known fibronectin receptor, alpha 5 beta 1, and an integrin with undefined ligands, alpha 6 beta 4. Function-inhibitory monoclonal antibodies specific for the alpha 1, alpha 2, alpha 3, alpha 5, and alpha 6 integrin subunits were used to determine the roles of individual integrins in mediating neurite outgrowth by DRG neurons on laminin. The results demonstrate that alpha 1 beta 1 and alpha 3 beta 1 function as laminin receptors on these neurons. As many as 18 distinct isoforms of laminin may exist, assembled as heterotrimers containing one each of the different A, B1, or B2 subunit homologs. In the present study, we characterize neurite outgrowth in response to two of these isoforms, the AeB1eB2e isoform and the AmB1eB2e isoform. Results utilizing DRG neurons and a pheochromocytoma cell line (PC12) indicate that these two isoforms exhibit differential selectivities for the alpha 1 beta 1 and alpha 3 beta 1 integrins.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1976

[Simple and rapid method for direct coliform analysis in seawater].

A simple and rapid test for the fecal coliform analysis in seawaters by means of the direct seeding on selective-differential m-FC agar medium is described. The data set fourth show a good yield for the test insofar as test sensitivity, specificity and reliability are concerned. Consequently, its use is proposed along with, or at variance with, the traditional techniques MPN and FM which are not always of practical and easy carrying out, under particular operative conditions (need to customarily analyse a high number of samples).

Escherichia coli↗

PubMed1993

The physiology of bcl-2 expression in murine B lymphocytes.

Quantitation of bcl-2 gene expression in B-lineage lymphocytes from normal adult mice allows the identification of four cell populations, characterized by successive three- to fivefold increases in average mRNA levels: bone marrow pre-B cells, bone marrow B cells, splenic B cells and long-lived splenic B cells. Thus, in line with previous experiments using overexpression systems, a correlation between longevity and levels of bcl-2 mRNA exists also in the physiology of B-lineage cells. The data are compatible with a quantitative regulation of expression, possibly determined at selective differentiation steps. No difference in bcl-2 expression was detected by comparing splenic IgD+ with IgD- B cells, while distinctly low levels of bcl-2 mRNA were scored in peritoneal CD5+ and CD5- B cells. These observations indicate that the reported persistence of peritoneal B cells may be controlled by mechanisms other than bcl-2 gene expression.

Animals↗