Very low density lipoprotein apolipoproteins B-100 and E turnover in control subjects using L-[1-13C]-leucine.
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Apolipoprotein B-100↗
Biomedical subjects
P Garcia
Publications and source records attributed to P Garcia.
The insertion site of the temperate phage HB-746 is located near the phage remnant in the pneumococcal host chromosome.
Combined Southern blot hybridization analyses of DNA digests of several clinical strains of Streptococcus pneumoniae have revealed the presence of a gene (hblR), or part of it, similar to the hbl7 gene coding for the cell wall lytic enzyme of the temperate HB-746 phage. The results confirmed that the genome of HB-746, which contains protein covalently linked to the 5' ends of its DNA, becomes integrated into the host strain 8R1 and showed that both the host and phage attachment sites, attB and attP, lie downstream of the 3' end of the structural region of the hblR and hbl7 genes, respectively. The data reported also highlight some evolutionary relationships between phage and bacteria.
Bacteriophages↗
Prevalence of post-headshake nystagmus in patients with caloric deficits and vertigo.
Post-headshake nystagmus (PHN) has recently been described as a clinically useful physical sign implying uncompensated asymmetric input from the vestibular end organs. A rapid 20-second headshake and sudden stop produces a jerk nystagmus of 5- to 20-second duration in certain individuals with symptoms suggestive of a peripheral vestibulopathy. This retrospective review of 214 patient evaluations was undertaken to study the associations between post-headshake nystagmus, caloric deficits after bithermal binaural irrigation, and the presence of vertigo. Both clinical observation of the nystagmus with eyes open (PHN-OBS) and routine EOG recording with eyes closed (PHN-EOG) were used. In patients with unilateral caloric deficits, 42% (18 of 43) had PHN-EOG, compared with 18% (3 of 17) in patients with bilateral dysfunction and 15% (23 of 154) in patients with normal calorics (p less than 0.001). In similar fashion, 26% (32 of 124) of patients with vertigo (recent or past) had PHN-EOG compared to 13% (12 of 90) of patients without vertigo (p less than 0.03). Finally, of 110 cases with both PHN-EOG and PHN-OBS performed, 45% (9 of 20) with PHN-EOG also had PHN-OBS, as opposed to only 4% (4 of 90) without PHN-EOG displaying PHN-OBS (p less than 0.0001). We conclude that the prevalence of post-headshake nystagmus is increased in patients with either a unilateral caloric deficit or a history of true vertigo, and is best detected in the absence of vision.
Adolescent↗
ProMACE-C-MOPP in aggressive non-Hodgkin's lymphoma. Long-term results in 45 patients treated in a single institution.
Forty-five previously untreated patients with intermediate or high-grade non-Hodgkin's lymphoma were treated with the Pro-MACE-C-MOPP regimen (flexitherapy). The median age of the patients was 51 years, 51% had constitutional symptoms, 78% were in Ann Arbor stage III-IV, 40% had two or more involved extranodal sites and 87% had serum lactate dehydrogenase (LDH) above 225 U/l. Twenty-two (49%) patients had immunoblastic lymphoma (Working Formulation). Overall, 40% of the patients attained complete response (CR) and there were no relapses. The dose-limiting toxicity was myelosuppression (69% of the patients with WBC less than 1.9 x 10(9)/l). Three deaths were attributed primarily to chemotherapy, but another two patients died of long-term complications of therapy. After a median follow-up of 50 months (18-80), 15 patients (33%) were alive without lymphoma. Only histologic subtype (intermediate vs. high) and abdominal involvement were prognostic factors for CR rate. Our results indicate that ProMACE-C-MOPP is an effective regimen for intermediate-grade lymphomas. However, in high-risk patients the regimen seems to be less effective than originally reported.
Adolescent↗
Regional perinatal care in crisis: a case study of an urban public hospital.
Regionalized perinatal care is intended to guarantee pregnant women and neonates access to appropriate care regardless of ability to pay. Its effectiveness depends on the willingness of hospitals to transfer high-risk patients according to established protocols and affiliations. This study examines maternal transfers (n = 896) to Cook County Hospital (CCH), a public facility and a designated perinatal center in Chicago. In 1987 and 1988, the majority (68%) of maternal transfers to CCH came from out-of-network hospitals, and 52% of these came directly from another perinatal center. The data indicate that 62% of the out-of-network transfers who delivered were medically high-risk. The study also documents the transfer of women in active labor, a violation of federal law. The term "perinatal dumping" is introduced to mean the transfer of high-risk pregnant women between hospitals for economic rather than medical reasons. Strategies for safeguarding the integrity of regionalized perinatal care are discussed.
Adolescent↗
Erosive colitis in experimental canine Leishmaniasis.
Six 4 month-old beagles were inoculated with Leishmania infantum, three of them intraperitoneally (Group A) and the other three intravenously (Group B). The animals from Group A were killed at 109, 433 and 592 days after inoculation and animals from Group B 109, 171 and 334 days after inoculation. At 350 days (Group A) and 275 days (Group B) after inoculation, dogs started to develop a chronic large bowel diarrhoea. At necropsy a diffuse colonic and rectal wall thickening of gradually increasing severity was observed. Histological examination of the colon showed a diffuse inflammatory infiltration of the mucosa and submucosa by macrophages with amastigotes, lymphocytes, plasma cells and some neutrophils and eosinophils. The surface epithelium developed increasingly extensive degeneration, which caused the development of erosions on the mucosal surface. The crypts of Lieberkühn decreased in number and showed degeneration of the crypt epithelium.
Animals↗
Cochlear action potential tuning curves recorded with a derived response technique.
Previous action potential (AP) tuning curve methods have used a reduction in amplitude of the probe-elicited AP as an indication of tone-induced masking. The reduction criterion used in different studies has varied from 25% to 100%. For low level probe stimuli, which elicit a low-amplitude AP, this is a sensitive indicator. In contrast, for high-amplitude AP responses elicited by high-level stimuli, the required reduction in absolute terms is large, making it an insensitive indicator. AP tuning curves have been recorded using a sensitive method for detecting masker/probe interaction with a fixed criterion, unrelated to the unmasked AP amplitude. For each masking condition, a derived response was obtained by digitally subtracting the tone-masked AP waveform from the unmasked response. Derived responses are generated if there are ANY changes in the AP waveform induced by the masker, including amplitude changes, latency changes, or even changes in AP morphology not necessarily associated with the major peaks. A fixed criterion (10 microV) of tone-derived (TD) response was used as an indication of interaction of the responses to the masker and probe. Tuning curves generated by this method were compared with those generated by conventional amplitude reduction (AR) methods. TD tuning curves show different characteristics, especially with respect to increasing probe levels. They appear to give a good representation of the array of afferent fibers responding to a probe stimulus. In addition, frequency regions making minor contributions to the AP are better represented in TD tuning curves.
Animals↗
Sequence of the Streptococcus pneumoniae bacteriophage HB-3 amidase reveals high homology with the major host autolysin.
We have sequenced a DNA fragment containing the pneumococcal bacteriophage HB-3 hbl gene, which codes for the phage lytic amidase. A remarkable nucleotide similarity (87.1%) between the lytA gene, coding for the pneumococcal amidase, the major autolysin of Streptococcus pneumoniae, and the hbl gene was found. This similarity completely disappeared outside the open reading frames coding for both amidases. The hbl gene transformed amidase-deficient strains of S. pneumoniae to the wild-type phenotype, and Southern blotting experiments provided evidence for recombination between donor and recipient genes. A comprehensive evaluation of these and previous results on the peptidoglycan hydrolases of S. pneumoniae and its bacteriophages suggested that recombination mechanisms participate in the evolution of the genes coding for these enzymes.
Amidohydrolases↗
Characterization of the pneumococcal bacteriophage HB-3 amidase: cloning and expression in Escherichia coli.
HB-3, a temperate bacteriophage of Streptococcus pneumoniae, synthesizes its own murein hydrolase activity when multiplying on cultures of pneumococcus. The enzyme (HBL) was purified and biochemically characterized as an N-acetylmuramoyl-L-alanine amidase of 36,000 daltons, and a 2.1-kilobase DraI fragment containing the lysin gene (hbl) was cloned and expressed in Escherichia coli. Our results demonstrated that the primary product of the hbl gene is a form with low enzyme activity that can be converted to a more active form under conditions similar to those previously described for the major pneumococcal autolysin (E. García, J.L. García, C. Ronda, P. García, and R. López, Mol. Gen. Genet. 201:225-230, 1985). The phage-encoded amidase requires the presence of choline in the teichoic acids of the pneumococcal cell walls for in vivo and in vitro activity. Comparative biochemical and immunological tests of the phage-encoded and host amidases revealed a remarkable similarity between these enzymes, although analyses of their N-terminal amino acid sequences allowed us to conclude that the amidases are similar but not identical. This appears to be the first description of the cloning of a phage-encoded amidase in gram-positive bacteria.
Amidohydrolases↗
Temperate bacteriophages of Streptococcus pneumoniae that contain protein covalently linked to the 5' ends of their DNA.
We have characterized three temperate bacteriophages of pneumococcus (HB-3, HB-623, and HB-746). Although all the phages belong to the same family, the polypeptide composition of the virions and the DNA restriction endonuclease analysis of their DNAs revealed differences among the three phages. The genomes of these bacteriophages have been isolated as DNA-protein complexes. The protein is specifically associated with the two 5' termini of the DNA as shown by experiments carried out with exonucleases. The protein bound to the DNA in the three phages studied, iodinated in vitro with 125I, has a molecular weight of 23,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Treatment of the complexes with chaotropic agents suggested that the protein is covalently bound to the 5' termini of the DNA. Comparative pulsed-field gel electrophoresis analysis and Southern hybridization of the SmaI restriction fragments of DNAs from one lysogenic bacteria and its parental strain revealed that the prophage genome was integrated in the host chromosome.
Bacteriophages↗
Allelic and genotypic composition of ancestral Spanish and colonial Californian gene pools of Avena barbata: evolutionary implications.
Spanish explorers and colonists inadvertently started a massive experiment in evolutionary genetics when they accidentally introduced Avena barbata to California from Spain during the seventeenth and eighteenth centuries. Assays of the Spanish and Californian gene pools of this species for 15 loci show that the present day Spanish gene pool, particularly that of Southwestern Spain, is identical or virtually identical to that of California for five loci and closely similar for nine loci. Despite their similar allelic and single-locus genotypic compositions, the present-day Spanish and Californian gene pools are differently structured on a multilocus genetic basis. Evolutionary implications of these results are discussed.
Alleles↗
Drug resistance of M. tuberculosis in Chile: rates of initial resistance for 1986 and acquired resistance for 1985.
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Antitubercular Agents↗
DNA sequences required to induce localized conversion in Streptococcus pneumoniae transformation.
In pneumococcal transformation a particular point mutation belonging to the amiA locus is able markedly to enhance recombination frequency when crossed with any other markers of this gene. This results from a polarized conversion of the mutation towards the wild-type sequence. In this report, by site-directed oligonucleotide mutagenesis, we have generated a series of mutants showing various degrees of conversion. We have found that the substitution 5'-ATTCAT----5'-ATTAAT is a sufficient signal for localized conversion. Changing individual bases within this sequence results in decreased conversion frequencies to levels that depend on the mutation, suggesting that there is a family to related sequences which may act as a substrate for a conversion system. Moreover, the length over which this conversion occurs has been estimated to be 12 base pairs on the average.
Base Sequence↗
Surgical gauze pseudotumor.
Gauze forgotten at operations can be potentially life threatening, but such cases are seldom reported because of the medicolegal implications. We have presented a series of seven patients with long-term surgical gauze retention, four after pelvic operations, one after cholecystectomy, one after laryngectomy, and one after mastectomy. The median time interval between operation and gauze removal was 5 years. In three patients this was diagnosed as a tumoral mass, in three as an intestinal occlusion, and in one the gauze was found incidentally. All foreign bodies were removed and no patient died. The clinical and diagnostic aspects of retained surgical gauze have been discussed and the need for radiopaque markers in them have been emphasized.
Bandages↗
An experimental orthopedic treatment of the rat mandible using a functional appliance alters the fibre and myosin types in masticatory muscles.
Masticatory muscles mediate the action of functional orthopedic appliances on mandible growth. When young rats were treated for four weeks with a postural hyperpropulsor of the mandible, an appliance designed to increase condylar cartilage growth rate, the proportion of fast non-fatigable fibres in the lateral pterygoid muscle increased significantly. Concomitantly, the amount of slow-myosin light chains increased in fibre extracts. This slow myosin originated from IIA fibres. By functional orthopedic treatment, the lateral pterygoid muscle was enriched in less fatigable fibres; the changes observed in the lateral pterygoid muscle were close to changes observed in other muscles after training.
Adenosine Triphosphatases↗
Inhibition of DNA repair by neighbouring mismatched bases in Streptococcus pneumoniae.
A set of pneumococcal strains containing immediately adjacent or nearby double mutations at the amiA locus, conferring resistance to amethopterin, has been isolated by oligonucleotide site-specific mutagenesis. Repair of these double mutations has been measured by transformation of wild-type strains with DNA extracted from these strains. In several transformations we have observed an inhibition of repair by neighbouring mismatches. This inhibition ranges from mild to severe depending upon the interfering mismatch. Unrepaired mismatches can strongly inhibit repair of an adjacent repairable mutation. This suggests that the repair-complex proteins attach not only to repairable mismatches but also to some mismatches known to escape the repair system.
DNA Repair↗
[Reliability and perspectives in peroperative flowmetry. An original computer-assisted ultrasonic technic].
To mitigate the lack of reliability of currently used flowmetry technics, an original method was developed based on a single window 15 MHz Doppler flowmeter and an Apple IIe computer with data acquisition system. Eleven successive measurements of instantaneous rate were made in an arterial section. A mean flow was determined by integration of mean rate in section. The reliability of the method was evaluated by an experimental study on a hydrodynamic bench reproducing physiologic flow conditions with an error always less than 8%. An in vivo study in 30 patients provided 100 measurements of arterial flow before and after surgical arterial reconstruction. The mean error value was less than 10%. Among the risks of error, those due to the probe was reduced by specially conceived probes. The most important factor was that of respiration, this latter factor imposing an integration time of rate of signal of 30 seconds to eliminate errors due to respiration. The conventional measurement time for other configurations is 6 seconds but this leads to a mean error of 25% which can attain 60%. The perspective of miniaturization of the apparatus in the near future with acceleration of measurements using a multi-window Doppler should allow flow measurement in 30 seconds and control of surgical reconstructions (on healthy arteries, vein grafts and prostheses but excluding PTFE). Similarly, it should be possible to improve evaluation of so-called vasoactive drugs.
Arterial Occlusive Diseases↗
Mismatch repair during pneumococcal transformation of small deletions produced by site-directed mutagenesis.
The genetic behaviour of short non-homologous regions has been studied during transformation of Streptococcus pneumoniae. Amethopterin-resistant mutants belonging to the amiA locus were used for these investigations. Five mutants deleted for 1-5 bp were obtained by oligonucleotide-directed mutagenesis. Their efficiency of transformation was measured using recipient strains either able to excise and repair mismatched bases (Hex+) or Hex- derivatives. Deletions or insertions of 1 and 2 bp are fully recognized by the Hex system, and are efficiently repaired whereas 3-bp deletions or insertions are only partially excised and repaired. The efficiency of repair is inversely related to the size of the non-homology. Markers with 5-bp deletions or insertions are poorly repaired and thus transform at very high frequency: similar results are obtained in reciprocal crosses. It is proposed that 1- or 2-bp deletions or insertions are included in the heteroduplex structure as transition mutations. The Hex system would detect only small deviations from the normal DNA structure.
Chromosome Deletion↗