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At least 343 records · Page 19Linked to original sources
PubMed1989

[Effect of a combination of heparin-glucuronylglucosaminoglycan for topical use in modification of pain in osteoarthritis of the knee].

The aim of the study was to evaluate the therapeutic effects of a Heparin-Glucuronilglucosaminoglycane association for external use in patients affected with painful osteoarthritis of the knee. The cutaneous pain threshold and subcutaneous tissue thickness at periarticular level were chosen as parameters for evaluation. In a previous experimental study, they proved to be reliable indexes of pain-related alterations of sensitivity and trophism. These parameters were measured in basal conditions and after 10, 20 and 30 days respectively of therapy consisting in 3 daily administrations of the drug. The measurements were also repeated 30 days after the interruption of the treatment. The cutaneous pain threshold and the subcutaneous tissure thickness underwent an increase and a decrease respectively in comparison with basal values in all the determinations performed. These increases and decreases were statistically significant throughout the whole period of treatment and remained significant even after the interruption of the drug administration (significant levels between p less than 0.04 and p less than 0.001). The possible mechanisms of such effects were examined, according to the pharmacological characteristics of the drug and the pathophysiology of pain and inflammation.

Administration, Topical↗
PubMed1984

Contraction stress test by intermittent nipple stimulation.

Although the nonstress test has generally supplanted the contraction stress test as the primary test for assessment of fetal well-being, the contraction stress test continues to be useful. Objectionable factors of the contraction stress test have included the time required to complete the test and the frequent necessity for intravenous oxytocin. The authors developed a contraction stress test protocol using contractions produced by intermittent nipple stimulation and used the method for 345 tests on 193 high-risk pregnancies during a 15-month period. The women were instructed to stimulate one breast, through their clothes, for two minutes and then to rest for five minutes. This cycle was repeated as necessary, but was interrupted whenever contractions began. Using this protocol, the authors were successful in achieving an adequate contraction frequency with every attempt, and hyperstimulation was not more frequent than previously reported with the standard contraction stress test. The average time requirement was 45 minutes. No unexplained stillbirths occurred after a negative test.

Breast↗
PubMed1998

Optimized technical considerations for acquiring high-quality FDG studies with a dual-headed gamma camera.

OBJECTIVE: This retrospective analysis was designed to optimize the parameters and techniques required to successfully perform high-quality coincidence imaging in a general nuclear medicine department using a dual-headed gamma camera. METHOD: Coincidence imaging was performed on 33 patients after an intravenous injection of 3.0-5.0 mCi fluoro-2-deoxyglucose (18F-FDG). Data for all subjects were evaluated to determine which technical considerations contributed to an overall improvement in image quality. RESULTS: After reviewing the data for the 33 subjects, several modified techniques were implemented and parameters were adjusted that enhanced the overall quality of the images. The extremely short half-life of 18F restricts the opportunity to repeat studies that were delayed, interrupted or technically substandard. CONCLUSION: The review of the data indicated that strict adherence to protocol is necessary to achieve optimal results while attempting to incorporate this new imaging modality into a typical nuclear medicine department.

Fluorodeoxyglucose F18↗
PubMed2000

Conservation within artiodactyls of an AATA interrupt in the IGF-I microsatellite for 19-35 million years.

Occurrence of an AATA interrupt in the IGF-I microsatellite was investigated in a number of Artiodactyl species, namely pigs, camels, deer, cattle, goats, and sheep. Comparison of DNA sequences in the 5' flank of the microsatellite in these species revealed that the interrupt within the microsatellite is conserved in deer, cattle, sheep, and goats but is absent from camels and pigs. The interrupt was introduced into the Artiodactyl phylogeny after the divergence of the Camelidae but before the divergence of the Cervidae, and thus its time of origin can be estimated to be 19-35 MYA. In contrast to the repeat units which are hypermutable, the interrupt has been conserved for a very long time and may even have suppressed microsatellite variation by inhibiting replication slippage. A 12-bp deletion in the 5' flank of the microsatellite in camels corresponds to a consensus reversed repeat in deer, cattle, sheep, and goats with unknown functional significance. Apart from this deletion, the 5' flank of the microsatellite is highly conserved in Artiodactyl species.

Animals↗
PubMed1993

Interruption of a Trypanosoma cruzi gene encoding a protein containing 14-amino acid repeats by targeted insertion of the neomycin phosphotransferase gene.

In Trypanosoma cruzi, the cause of Chagas' disease in Latin America, a large proportion of the antigenic proteins described to date have repetitive domains. In earlier work we identified a partial length cDNA, designated TCR27, encoding approx. 26 copies of a 14-amino acid repeat and a unique 61-amino acid C-terminal region. The goal of the current project was to replace the repetitive region of a TCR27 gene with the neomycin phosphotransferase gene (NEOr). A pBluescript-based vector was constructed in which the 0.9-kb NEOr coding region replaced the 2.9-kb internal repetitive segment of a TCR27 gene and was in frame with its nonrepetitive 5' coding sequence (pTCR27-2::NEO). Epimastigotes were electroporated in the presence of linearized pTCR27-2::NEO and transfected clones were selected on solid medium containing G418. Southern and Northern analyses of DNAs and RNAs from four G418-resistant clones showed that in all cases the repetitive region in the smaller of the two TCR27 genes (TCR27-2) had been replaced by NEOr. The absence of the native TCR27-2 protein in the transfected clones was confirmed by Western blot. In axenic cultures growth rates of epimastigotes bearing an interrupted TCR27-2 gene were not different from those of wild-type parasites. In addition, there was no relative impairment of the four transfected clones' ability to proliferate in cultured mammalian cells. The fact that the clones having the interrupted TCR27-2 gene were not impaired biologically suggests that the length of the repetitive region of the TCR27 protein is not a critical factor for survival.

Amino Acid Sequence↗
PubMed2001

Repeated low-dose treatment of rats with pilocarpine: low mortality but high proportion of rats developing epilepsy.

Systemic administration of pilocarpine in rats can result in a chronic behavioral state that is similar to human temporal lobe epilepsy. The pilocarpine model of epilepsy is widely used for studying the factors that contribute to the development of epilepsy as a consequence of status epilepticus (SE). For this purpose, pilocarpine is either administered alone at a high systemic dose or in combination with lithium, which markedly potentiates the convulsant effect of pilocarpine. Both experimental protocols, however, are associated with high mortality rates. In the present study, we evaluated whether mortality rate in rats can be decreased by repeated administration of low doses of pilocarpine. The time the rats spent in SE was limited by diazepam. Preliminary experiments in lithium-free rats indicated that repeated low-dose administration of pilocarpine is too time-consuming to produce SE compared to single high-dose administration. All subsequent experiments were performed in lithium-pretreated rats. Single-dose injection of 30 mg/kg pilocarpine produced SE in approximately 70% of the animals, but 45% of the rats died although SE was interrupted by diazepam after 90 min. Repeated i.p. administration of 10 mg/kg pilocarpine at 30-min intervals resulted in SE after 2-4 injections; the mean dose of pilocarpine needed to induce SE was 26 mg/kg. When SE was interrupted after 90 min, mortality rate was below 10%, which was significantly lower compared to the protocol with one single administration of 30 mg/kg pilocarpine. In contrast to mortality rate, the development of spontaneous recurrent seizures did not differ between experimental protocols. Almost all rats which had experienced a SE of at least 60 min developed chronic epilepsy. Average latency to the first spontaneous seizure was approximately 40 days. The frequency and severity of spontaneous seizures was not significantly different between protocols, although animal groups with repeated low-dose treatment tended to have higher frequencies of spontaneous seizures compared to single-dose administration. The present study demonstrates that systemic treatment of lithium-pretreated rats with several low doses of pilocarpine efficiently produces SE and chronic epilepsy with much lower mortality rates than single-dose pilocarpine.

Animals↗
PubMed1978

Functional evaluation of normothermic intermittent coronary perfusion.

The myocardial contractility of papillary muscle from rabbit hearts was used to evaluate various techniques of normothermic intermittent coronary perfusion. A progressive decline of the myocardial contractility was noted as aortic cross-clamping and coronary reperfusion were repeated. After a net anoxic period of 90 minutes, the contractility fell to 58.67, 60.2, and 40 percent of the base line when single aortic cross-clamping time was 5, 10, and 15 minutes, respectively, interrupted by 5 minutes of reperfusion. Repeated application of single cross-clamping of 20 minutes or longer was not tolerated by the rabbit hearts. When the heart was reperfused for 10 minutes, between 15 minute periods of anoxia, the final recovery of contractility was 62 percent. Normothermic intermittent coronary perfusion has a significant adverse effect on the myocardial contractility. If this technique is to be used, single anoxic times should not be longer than 15 minutes and the heart must be reperfused for at least 10 minutes.

Animals↗
PubMed1999

Measurement of airway resistance using the interrupter technique in preschool children in the ambulatory setting.

This study describes the feasibility, repeatability, and interrater reliability of the measurement of airway resistance by the interrupter technique (Rint) in children 2-5 yrs of age, and examines whether reversibility to bronchodilator can be demonstrated in wheezy children. The mean of six Rint values was taken as a measurement. If subjects could complete one measurement and then a second 15 min after bronchodilator, baseline testing and reversibility testing were considered feasible. To measure repeatability, two measurements 30 s apart and measurements before and 15 min after placebo bronchodilator were compared. Measurements by two testers were compared for interrater reliability. Change in Rint in wheezy children was measured after bronchodilator. Fifty-six per cent of 2-3-yr-olds (n=79), 81% of 3-4-yr-olds (n=104) and 95% of 4-5-yr-olds (n=88) completed baseline testing, and 53%, 71% and 91% completed reversibility testing. Baseline measurements were 0.47-2.56 kPa x L(-1) x s. Repeatabilities (2 SD of the mean differences between measurements) at 30 s in the three age bands were 0.21, 0.17 and 0.15 kPa x L(-1) x s and 0.19 kPa x L(-1) x s after placebo. Using 0.21 kPa x L(-1) x s as the threshold for reversibility, reversibility was demonstrated in most wheezy children. Interrater reliability was 0.15 kPa x L(-1) x s. Preschool children can undertake measurements of airway resistance by the interrupter technique in ambulatory settings and reversibility to bronchodilator in wheezy children can be demonstrated. This technique promises to be a useful clinical and research tool.

Airway Resistance↗
PubMed1988

A novel insertion sequence in the cryptic plasmid of Neisseria gonorrhoeae may alter the B protein at the translational level.

A variant of the cryptic plasmid of Neisseria gonorrhoeae, 4.4 kb in size, was isolated and characterized at the molecular level. This variant harbored a 156-bp insertion which was located between coordinates 3134 and 3135 within the putative cppB gene using the 4.2-kb cryptic plasmid, pJD1, as a reference. The insertion contained a novel EcoRI site and several elements of symmetry (both direct and inverted repeats). Stop codons present in the insertion interrupted the coding capacity of the cppB gene. Although the insertion was within one of two previously characterized 44-bp repeats purportedly involved in site-specific recombination, it was distinct from a 54-bp segment deleted in some cryptic plasmids. The presence of the insertion suggests a mechanism of modulating the expression of the cppB gene at the translational level through DNA rearrangement.

Amino Acid Sequence↗
PubMed1993

Strong association between polymorphisms in an intronic microsatellite and in the coding sequence of the BoLA-DRB3 gene: implications for microsatellite stability and PCR-based DRB3 typing.

A highly polymorphic microsatellite in the bovine DRB3 gene was characterized by polymerase chain reaction (PCR) analysis and DNA sequencing. A very strong association between expressed DRB3 polymorphism and microsatellite alleles was revealed by PCR analysis of genomic DNA from 116 animals representing three breeds of cattle. The results indicated a low frequency of microsatellite length mutations as the association was consistent over breeds. The DRB3 microsatellite may be utilized in a PCR-based typing method of bovine class II alleles. The microsatellite polymorphism did not distinguish all known DRB3 alleles, but it was shown that this method may be complemented by the use of allele-specific PCR based on the extensive polymorphism in the DRB3 exon 2. The DNA sequences of seven microsatellite alleles, associated with different class II haplotypes, were determined. The DRB3 microsatellite is composed of three repeat motifs, a stretch of at least 10 uninterrupted (TG)n dinucleotides, a long but interrupted stretch of (GA)n dinucleotides, and a few (CAGA)n tetranucleotides. There were pronounced sequence differences between alleles and the results indicated that the evolution of this microsatellite has involved length mutations of the dinucleotide repeats as well as point mutations causing interruptions in the dinucleotide repeats.

Alleles↗
PubMed1996

Dissociation of hypoxia-induced chemosensory responses and catecholamine efflux in cat carotid body superfused in vitro.

1. To examine the correlation between chemosensory response and dopamine release induced by hypoxic stimulation, we studied carotid bodies excised from anaesthetized cats. 2. The carotid bodies with their carotid (sinus) nerves were superfused in vitro with modified Tyrode solution (pH 7.40, at 37.5 degrees C) equilibrated with 20 or 100% O2. The PO2 of the superfusing channel was monitored polarographically. The frequency of chemosensory discharges (fx) was recorded from the whole carotid nerve. Catecholamine (CA) efflux-mostly consisting of dopamine-was measured by high-speed chronoamperometry, through Nafion-coated carbon electrodes placed on the carotid body tissue. Chemosensory stimulation was induced by intrastream injections of NaCN, by superfusion with 100% N2-equilibrated saline (lowering PO2 to 25-40 Torr) or by flow interruption. 3. Low doses of NaCN increased fx, but had no measurable effect on CA efflux, while larger doses produced fast increases in fx, preceding delayed and prolonged increases in CA efflux. Repeated injections of NaCN, still increasing fx, gave reduced CA effluxes. 4. Switching to hypoxic superfusion for 6-8 min produced large and fast fx increases, but delayed and prolonged augmentations of CA efflux. 5. Administration of three to four boluses of dopamine (7-15 micrograms; augmenting CA concentration by up to 35 microM) initially decreased fx, after which hypoxic stimulation resulted in enhanced and faster CA effluxes, without changing the speed and intensity of chemosensory responses. 6. Flow interruptions induced fast increases in fx and delayed increases in CA efflux. Repeated flow interruptions produced similar increases in fx but progressively attenuated CA effluxes. 7. Our results suggest that CA efflux is not essential for hypoxia-induced chemosensory excitation in the cat carotid body. They also suggest the presence of two pools of releasable CAs in the carotid body, one of slow turnover and release, and another of recently incorporated dopamine and fast release, both pools being rapidly depleted by repeated stimulation of the carotid body.

Animals↗
PubMed1991

The effect of the length of direct repeats and the presence of palindromes on deletion between directly repeated DNA sequences in bacteriophage T7.

The frequency of genetic deletion between directly repeated DNA sequences in bacteriophage T7 was measured as a function of the length of the direct repeat. The non-essential ligase gene (gene 1.3) of bacteriophage T7 was interrupted with pieces of synthetic DNA bracketed by direct repeats of various lengths. Deletion of these 76 bp long inserts was too low to be measured when the direct repeats were less than 6 bp long. However, the frequency of deletion of inserts with longer direct repeats increased exponentially as the length of the repeats increased from 8 to 20 bp. When inverted repeats (palindromes) were designed in the midst of the insert there was essentially no increase in deletion frequency between 10 bp direct repeats. But, the same palindromic sequences increased the deletion frequency between 5 bp direct repeats by at least two orders of magnitude. Thus, in this system homology at the endpoints is a more important determinant of deletion frequency than is the presence of palindromes between the direct repeats.

Base Sequence↗
PubMed1996

Instability of repeated dinucleotides in bacteriophage T7 genomes.

The ligase gene of bacteriophage T7 was interrupted with an insert of synthetic DNA that included a series of dinucleotide repeats which altered the reading frame of the gene and prevented the phage from growing on a host deficient in Escherichia coli ligase. The insert was designed so that gain of an additional copy of the repeat would restore the reading frame and produce ligase positive T7. It was found that a pair of nucleotides was gained at a frequency of 1.4 x 10(-3) and a dinucleotide was lost from this sequence at a frequency of 1 x 10(-4). The same measurements were made using T7 with a DNA polymerase without the 3' --> 5' exonuclease function. This mutant DNA polymerase lacks proofreading edit function and is more processive than its wild-type counterpart. Phage without the edit function gained or lost a dinucleotide repeat significantly more frequently than wild-type T7. Thus, the frequency of two base frameshifting is very high during DNA replication. Proofreading activity attenuates the frequency of two base frameshifts. Inactivation of the 3' --> 5' exonuclease of T7 DNA polymerase had essentially no effect on the frequency of deletion of one member of a pair of 10 bp tandem repeats.

Bacteriophage T7↗
PubMed2000

Gene conversion (recombination) mediates expansions of CTG[middle dot]CAG repeats.

Genetic recombination is a robust mechanism for expanding CTG.CAG triplet repeats involved in the etiology of hereditary neurological diseases (Jakupciak, J. P., and Wells, R. D. (1999) J. Biol. Chem. 274, 23468-23479). This two-plasmid recombination system in Escherichia coli with derivatives of pUC19 and pACYC184 was used to investigate the effect of triplet repeat orientation on recombination and extent of expansions; tracts of 36, 50, 80, and 36, 100, and 175 repeats in length, respectively, in all possible permutations of length and in both orientations (relative to the unidirectional replication origins) revealed little or no effect of orientation of expansions. The extent of expansions was generally severalfold the length of the progenitor tract and frequently exceeded the combined length of the two tracts in the cotransformed plasmids. Expansions were much more frequent than deletions. Repeat tracts bearing two G-to-A interruptions (polymorphisms) within either 171- or 219-base pair tracts substantially reduced the expansions compared with uninterrupted repeat tracts of similar lengths. Gene conversion, rather than crossing over, was the recombination mechanism. Prior studies showed that DNA replication, repair, and tandem duplication also mediated genetic instabilities of the triplet repeat sequence. However, gene conversion (recombinational repair) is by far the most powerful expansion mechanism. Thus, we propose that gene conversion is the likely expansion mechanism for myotonic dystrophy, spinocerebellar ataxia type 8, and fragile X syndrome.

Base Sequence↗
PubMed1987

Organization of the gene for human factor XI.

Factor XI (plasma thromboplastin antecedent) is a plasma glycoprotein that participates in the early phase of blood coagulation. The gene for the human protein has been isolated from two different lambda phage genomic libraries. Four independent recombinant lambda phage carrying overlapping DNA inserts that coded for the entire gene for factor XI were isolated and characterized by restriction mapping, Southern blotting, and selective DNA sequencing to establish the number and location of the intron-exon boundaries. The gene for human factor XI was 23 kilobases in length and consisted of 15 exons (I-XV) and 14 introns (A-N). Exon I coded for the 5' untranslated region, and exon II coded for the signal peptide. The next eight exons (III-X) coded for the four tandem repeats of 90 or 91 amino acids that were present in the amino-terminal region of the mature protein. Each of these tandem repeats was coded by two exons that were interrupted by a single intron, and these introns were located in essentially the same position within each of the four tandem repeats. The carboxyl-terminal region of the protein, which contained the catalytic chain, was coded by five exons (XI-XV) that were interrupted by four introns. The last four introns were located in the same positions as those in the genes for human tissue plasminogen activator and human urokinase.

Amino Acid Sequence↗
PubMed2001

How should airways resistance be measured in young children: mask or mouthpiece?

The reproducibility and acceptability of airways resistance measurements using the interrupter technique (MicroRint) obtained using a mouthpiece were compared with those using a face mask. Fifty children aged 4-7 yrs performed four sets of six Rint measurements; two using a mouthpiece and two using a face mask with integral mouthpiece. Complete data were obtained from 45 (90%) children using the mouthpiece and 43 (86%) children using the mask. The two methods were equally repeatable with comparable intraclass correlation coefficients (ICC) and coefficients of variation. Mean Rint values obtained using the mouthpiece were significantly lower than those using the face mask ((mean+/-SD) mouthpiece=0.81+/-0.18 kPa x L(-1) x s, mask=0.88+/-0.24 kPa x L(-1) x s p=0.0002). Although the mean paired differences between the two methods were small (0.07 kPa x L(-1) x s), the ICC and limits of agreement confirmed that the two methods could not be used interchangeably. Sixty-seven per cent of children preferred the face mask but this was more time-consuming (p = 0.03). Children did not produce more repeatable results using their preferred method, nor did they improve with practice. Repeatable airway resistance measurements using the interrupter technique can be obtained from young children using either a mouthpiece or a face mask, but there are significant clinical and statistical differences between the results obtained.

Child↗
PubMed1989

Opiate antagonist treatment reinstates estrous cycles in middle-aged persistent-estrous rats.

Middle-aged female rats display luteinizing hormone (LH) surge deficits and cycle irregularity followed by the onset of persistent estrus (PE). The central nervous system has been identified as a primary locus of failure in PE rats, but the particular neural elements involved have not been determined. The goal of the present study was to identify a role for endogenous opioid peptides (EOP) in age-related acyclicity by evaluating the effect of opiate antagonist treatment on vaginal cytology in PE rats. PE rats were administered, s.c., saline (SAL), naloxone (NAL) or naltrexone (NTX) once daily for 20 days, or repetitively on Day 1 and on successive proestrus days if cyclicity was resumed. Single NTX (50 mg/kg), but not NAL (2 mg/kg), treatment interrupted the PE state in almost half of treated animals. Daily or repetitive proestrus NTX (10 mg/kg) treatment interrupted PE more frequently, and many animals displayed repeated estrous cycles and ovulation. Afternoon LH surges were observed after initial NTX treatment in animals displaying PE interruption. This demonstration that LH surges and ovulatory cycles can be reinitiated in PE rats with NTX suggests that dysfunction in the 'brake' on EOP secretion during proestrus may be one of the neuroendocrine impairments mediating acyclicity in aging female rats.

Aging↗
PubMed2000

SCA8 CTG repeat: en masse contractions in sperm and intergenerational sequence changes may play a role in reduced penetrance.

We recently described an untranslated CTG expansion that causes a previously undescribed form of spinocerebellar ataxia (SCA8). The SCA8 CTG repeat is preceded by a polymorphic but stable CTA tract, with the configuration (CTA)(1-21)(CTG)(n). The CTG portion of the repeat is elongated on pathogenic alleles, which nearly always change in size when transmitted from generation to generation. To better understand the reduced penetrance and maternal penetrance bias associated with SCA8 we analyzed the sequence configurations and instability patterns of the CTG repeat in affected and unaffected family members. In contrast to other triplet repeat diseases, expanded alleles found in affected SCA8 individuals can have either a pure uninterrupted CTG repeat tract or an allele with one or more CCG, CTA, CTC, CCA or CTT interruptions. Surprisingly, we found six different sequence configurations of the CTG repeat on expanded alleles in a seven generation family. In two instances duplication of CCG interruptions occurred over a single generation and in other instances duplications that had occurred in different branches of the family could be inferred. We also evaluated SCA8 instability in sperm samples from individuals with expansions ranging in size from 80 to 800 repeats in blood. Surprisingly the SCA8 repeat tract in sperm underwent contractions, with nearly all of the resulting expanded alleles having repeat lengths of <100 CTGs, a size that is not often associated with disease. These en masse repeat contractions in sperm likely underlie the reduced penetrance associated with paternal transmission.

Alleles↗