Biomedical subjects
Publications and source records attributed to A Martinez.
The segment of the rho gene that harbors the ts15 mutation was isolated and sequenced. The mutation, an IS1 insertion, changed the sequence of the C-terminal nine amino-acid residues, altering seven and eliminating the last two.
PURPOSE: To obtain reliable data on the extent of the brachytherapy practice in the United States by conducting a comprehensive survey of all facilities. METHODS AND MATERIALS: The Clinical Research Committee of the AES surveyed all 1321 radiation oncology facilities identified in the Patterns of Care Study (PCS) of the American College of Radiology (ACR). Multiple mailings and follow-up were made to obtain a high response rate. Survey responders and nonresponders were compared using chi-square tests. Summary statistics were reported. RESULTS: Of the 1321 facilities, 1054 responded (80%). Hospital-based and larger facilities had a statistically significant higher rate of response. Brachytherapy was being performed at 819 facilities (the median number of procedures = 21-50). Two hundred and two facilities did no brachytherapy. The common isotopes used were 137Cs (705 facilities), 192Ir (585 facilities), 125I (236 facilities), and 131I (194 facilities). The common brachytherapy techniques used were intracavitary (751 facilities), interstitial (536 facilities), intraluminal (310 facilities), and plaques (148 facilities). Remote afterloaded brachytherapy was used at 205 centers as follows: high dose rate (HDR) (164), medium dose rate (MDR) (5), and low dose rate (LDR) (36). Computerized dosimetry was most commonly used (790 facilities), followed by Patterson-Parker (104 facilities) and Quimby (72 facilities). The common sites treated were cervix (701 facilities), endometrium (565 facilities), head and neck (354 facilities), and lung (344 facilities). CONCLUSION: Data regarding brachytherapy practice has been obtained from a large percentage (80%) of all facilities in the United States. The majority (78-81%) of radiation oncology facilities perform brachytherapy; however, its use is restricted to gynecological implants in many of these centers. The results from this survey will be used to develop a pattern of care study and data registry in brachytherapy.
The ubiquitously expressed upstream stimulatory factor (USF) involved in the transcription of a wide variety of cellular genes is defined as dimers of c-myc-related proteins, composed of a basic helix-loop-helix/leucine zipper region. The USF family consists of different members that split into two groups: MLTF or USF1 and USF2 or FIP. We present here evidence that USF1 and USF2 are distinct closely related genes in human, rat, and mouse. Based on the recent cloning of rat and human new cDNAs, we have isolated genomic clones encompassing the murine USF2 gene, which consists of at least 10 exons spanning a minimum of 10 kb of genomic DNA. Unexpectedly, the organization of USF2 appears very split up by introns (0.08 to over 6 kb in size), compared to the myc gene structure. The entire gene (but the larger intron) and 1.6 kb of the 5' flanking region were sequenced. This 5' flanking region is GC-rich, contains several putative transcription binding sites, and has no apparent TATA box. Gene mapping of murine USF2 and USF1 has been determined by in situ hybridization, indicating the localization of USF2 on chromosome 7 and of USF1 on chromosomes 1 and 11.
The mutation S349P in exon 10 of the phenylalanine hydroxylase (PAH) gene was identified in one Norwegian and one Polish phenylketonuria (PKU) allele on a haplotype 1.7 background. This missense mutation in PAH codon 349 is a T to C transition in cDNA position 1267. This mutation has been reported both on haplotype 1 and 4, suggesting recurrent mutation. In two different expression systems, the pET and the pMAL systems of Escherichia coli, it was shown that the S349P mutation, introduced by site directed mutagenesis, results in complete loss of enzymatic activity. Thus, protein instability alone does not seem to be the direct cause of the lack of activity of this PKU mutation as previously reported.
OBJECTIVES: Temporomandibular joint (TMJ) arthrocentesis and lavage, first described in the North American literature in 1991, is a simplified method used for the treatment of severe, limited mouth opening. The purpose of this study is to evaluate the efficacy of this technique as a treatment for closed lock of the TMJ. DESIGN: Forty-six patients with persistent closed lock of the TMJ of acute onset were treated by TMJ arthrocentesis and lavage with manipulation in an out-patient setting. Clinical data was collected in the form of visual analogue scales for pain and chewing ability, and measurements of maximum mandibular opening before and after treatment. RESULTS: On follow-up ranging from 6 to 30 months, jaw opening and mandibular function had significantly improved (p < 0.001), and pain had substantially decreased in all but one patient as a result of this procedure. CONCLUSION: TMJ arthrocentesis and lavage is recommended as a simple alternative to more invasive TMJ procedures as an effective technique for the treatment of acute persistent closed lock of the TMJ.
The presence of migrating callosal neurons during the development of the murine cerebral cortex was studied using biocytin and the lipophilic dye, 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate as retrograde tracers. After injections of biocytin in the presumptive somatosensory cortex of newborn mice which were analysed one day later, many anterogradely labelled fibres coursed towards the contralateral hemisphere through the corpus callosum. Retrogradely labelled callosal cells were also observed. Most callosal neurons corresponded to immature pyramidal cells. In addition, a few biocytin-labelled callosal neurons displayed extremely fusiform shapes, vertical orientation and a short, single process emerging from the apical side of the perikaryon. At the electron microscopic level, these cells had features identical to those described for migrating callosal neurons. Twenty-four hours after birth, these migrating neurons were almost exclusively observed in the upper, dense aspect of the cortical plate (presumptive layers II-III) and only very exceptionally in the infragranular layers. No retrogradely labelled cell resembling migrating neurons were noticed after injections on postnatal days 2 or 5. To study migrating callosal neurons at embryonic stages, crystals of the lipophilic dye were injected in the corpus callosum or the contralateral white matter in embryos aged 17, 18 and 19 days, corresponding to the initial development of the corpus callosum in mice. Whereas callosal migrating neurons were not detected at embryonic days 17 and 18, injections of the lipophilic dye on embryonic day 19 revealed the presence of labelled migrating neurons in the infragranular layers. To corroborate further that these cells are migrating neurons, [3H]thymidine was administered on embryonic days 16 and 17, and labelled mice were injected with biocytin on embryonic day 19 or the first postnatal day. Retrogradely labelled callosal neurons resembling migrating neurons were autoradiographically labelled. These results indicate that the specification of certain neuronal types and the emergence of their cell type-specific characteristics occur shortly after postmitotic neurons leave the ventricular zone, before being positioned within the cortical plate.
Mouse vas deferens protein (MVDP) is a major androgen-dependent protein of deferential fluid. It is specifically expressed in the epithelium of the mouse vas deferens. Its amino acid sequence as deduced from the nucleotidic sequence of its cDNA does not possess a signal sequence characteristic of secretory proteins. In vitro, transcription of MVDP cDNA followed by translation of mRNA in the rabbit reticulocyte system, in the absence or the presence of microsomes, demonstrated that there was no internalization of MVDP into microsomes that could protect it from degradation by proteinase K; this confirmed the absence of signal sequence. Moreover, MVDP has its NH2-terminus blocked. To understand how MVDP can be exported, its ultrastructural distribution and secretion process were analyzed by means of electron microscopy. Immunolocalization of MVDP revealed that it was distributed in the whole cytoplasm; it was never detected in the lumen of endoplasmic reticulum, Golgi apparatus, or vesicles but was abundant in apical protrusions and in the fluid, where it was associated with cellular material undergoing degradation. These data clearly demonstrated that exportation of MVDP into the luminal fluid does not occur in the classical manner for secretory proteins but rather involves an apocrine secretion process.
OBJECTIVE: The aim of this investigation was to study the effect of relatively high dose IGF-I therapy given for several months, on serum levels of IGF-I, IGF-II and IGFBP-3, and on IGF-I pharmacokinetics in patients with growth hormone insensitivity due to GH receptor dysfunction. DESIGN AND PATIENTS: Two adolescent subjects from Ecuador were treated with recombinant IGF-I at a dosage of 120 micrograms/kg s.c. twice daily, in combination with a GnRH analogue for 8 months. MEASUREMENTS: Serum was sampled at baseline and at 3-8 months, for determination of IGF-I, IGF-II and IGFBP-3 by radioimmunoassay, and for evaluation of IGFBPs and IGFBP-3 protease activity by Western ligand blot and protease assay, respectively. RESULTS: Peak serum IGF-I levels ranged from 272 to 492 micrograms/l. Mean serum IGF-II levels were decreased concurrently with the increase in IGF-I. Serum IGFBP-3 levels failed to rise with prolonged IGF-I treatment. There was no apparent change in the half-life of IGF-I during the treatment period. CONCLUSIONS: IGF-I administration does not increase serum levels of IGFBP-3 or significantly alter IGF-I pharmacokinetics.
Sensitization to Quercus ilex (holm oak) was studied in 760 patients with clinically suspected sensitization to aeroallergens. Prick tests with commercial extracts of Q. ilex proved positive in 27 patients; none were monosensitive. Nasal and conjunctival provocation tests and specific IgE (RAST) performed with Q. ilex extracts in these patients were negative in all but one patient, who exhibited specific IgE titer (by RAST) of 7 PRU/ml (class 3). We conclude that Q. ilex pollen, though obtained in considerable quantities by our collector, does not cause allergies in our area.
We report the cloning of the pykA and pykF genes from Escherichia coli, which code for the two pyruvate kinase isoenzymes (ATP:pyruvate 2-O-phosphotransferases; EC 2.7.1.40) in this microorganism. These genes were insertionally inactivated with antibiotic resistance markers and utilized to interrupt one or both pyk genes in the E. coli chromosome. With these constructions, we were able to study the role of these isoenzymes in pyruvate biosynthesis.
Brain microvascular endothelial cells play an important role in regulation of ion and fluid movement between the blood and the brain interstitium. Astrocytes have been shown to induce blood-brain barrier properties in the endothelial cells, including formation of tight junctions and increased expression and asymmetric distribution of enzymes and ion transport systems. Previous studies have demonstrated that endothelial cells of bovine aorta possess a highly active Na-K-Cl cotransport system that participates in intracellular volume regulation. The present study was conducted to evaluate Na-K-Cl cotransport activity of cerebral microvascular endothelial cells and to determine whether astrocyte-conditioned medium (CM) influences Na-K-Cl cotransport activity of these cells. We found the brain microvascular endothelial cells to exhibit a robust Na-K-Cl cotransport activity, comprising 50% of the total K influx. Activity of the cotransporter was stimulated by agents that elevate intracellular Ca and by hypertonicity and was inhibited by agents that elevate adenosine 3',5'-cyclic monophosphate, guanosine 3',5'-cyclic monophosphate, or activate protein kinase C. Exposure of the cells to primary astrocyte- or C6 glial cell-CM but not A7r5 or A10 vascular smooth muscle cell-CM also increased cotransport activity. However, this effect required > 1 h of exposure to CM, was additive with the effects of vasopressin, calcium ionophore, and hypertonicity, and was blocked by the protein synthesis inhibitor cycloheximide.(ABSTRACT TRUNCATED AT 250 WORDS)
The Na-K-Cl cotransport system of vascular endothelial cells plays a central role in maintenance and regulation of intracellular volume. Activity of the cotransporter is modulated both by hormones and by extracellular tonicity. Vasopressin and other hormones that stimulate the endothelial cotransporter act via a Ca- and calmodulin-dependent pathway. Little is known, however, about the mechanisms that mediate cell shrinkage-induced stimulation of cotransport activity. In the present study, we evaluated the Ca dependence of cell shrinkage-stimulated Na-K-Cl cotransport activity and cell volume recovery of cultured bovine aortic endothelial cells and also the effects of protein kinase and phosphatase inhibitors on these processes. In addition, to investigate the possibility that hormones and/or hypertonicity regulate endothelial Na-K-Cl cotransport via direct phosphorylation of the cotransporter protein, we employed a monoclonal antibody to the human colonic T84 epithelial cell Na-K-Cl cotransport protein (T4 antibody) for Western blot analysis and immunoprecipitation of phosphoprotein. Our studies revealed that both cell shrinkage-stimulated net K uptake and recovery of intracellular volume were Ca dependent. We also found that hypertonicity-induced stimulation of cotransport activity was blocked by several inhibitors of Ca- and calmodulin-dependent protein kinases. Furthermore, inhibitors of myosin light chain kinase blocked cell shrinkage-stimulated cotransport and recovery of intracellular volume, while having no effect on vasopressin-stimulated cotransport. Western blot analysis of bovine aortic and cerebral microvascular endothelial cell membrane preparations revealed a 170-kDa protein recognized by the T4 antibody. In addition, we found that hypertonicity induced a marked increase in phosphorylation of the endothelial cotransport protein, as did vasopressin, bradykinin, okadaic acid, and calyculin A. Our findings indicate that modulation of endothelial cell Na-K-Cl cotransport activity by hypertonicity and by stimulatory hormones occurs via pathways involving Ca- and calmodulin-dependent protein kinases and direct phosphorylation of the cotransport protein.
We previously demonstrated that prenatal corticosteroids attenuated the expected exponential increase in circulating catecholamines at birth. The present studies were undertaken to determine if alteration in sulfoconjugation could account for this attenuation. Catheterized fetal lambs received saline (n = 6) or corticosteroids (n = 8) intravenously for 60 h. The lambs were delivered by cesarean section at 130 +/- 1 days gestation. Ventilatory and cardiovascular responses and plasma catecholamine concentrations were measured for 2 h after birth. Although plasma free catecholamines levels were higher in controls than in corticosteroid-treated fetuses, the sulfoconjugated levels were similar in the two groups. Thus the corticosteroid-treated fetuses had a higher proportion of plasma sulfoconjugated catecholamines consistent with the possibility that sulfoconjugation was augmented during intrauterine life. After birth, the corticosteroid-treated animals showed an attenuated increase in plasma free catecholamine levels compared with controls but a similar increase in sulfoconjugated catecholamine levels to the control animals. The proportion of plasma sulfoconjugated catecholamines was higher in the corticosteroid-treated animals; however, the increase in sulfoconjugated catecholamines was insufficient to account for the attenuated overall increase in total catecholamines in the corticosteroid-treated animals.
To determine the final height of patients with precocious puberty treated with medroxyprogesterone acetate (MPA; 150 mg every week) for a period > 1 year (mean +/- SD = 3.24 +/- 1.85 years), data from a group of 26 girls were analyzed. The attained final height was 155.6 +/- 8.06 cm (-1.1 SD of the normal population). In a group of 8 untreated girls with precocious puberty, adult height was 149.2 +/- 5.07 (-2.16 SD, p < 0.02). In 9 patients in whom treatment was stopped at a bone age < or = 12 years, final height was 159.2 +/- 10.05 cm, while in 16 girls who had a bone age > 12 years at the end of treatment, the final height was 153.03 +/- 6.28 cm. Our data demonstrate the effectiveness of MPA treatment on ultimate height. The better height observed in those patients who stopped treatment with a bone age < 12 years suggests the advantage of discontinuing therapy before reaching a more advanced degree of skeletal maturation.
Adrenomedullin (AM) is a potent hypotensive peptide recently discovered in extracts of human pheochromocytoma. In this report we present evidence, using reverse transcriptase-polymerase chain reaction, immunocytochemistry, and in situ reverse transcriptase-polymerase chain reaction, that AM is synthesized by several cell populations of the normal lung, tumor cell lines of pulmonary origin, and tumor specimens. Among the normal cell populations of the lung, we found AM expression in the columnar epithelium, some glands, neurons of the pulmonary parasympathetic nervous system, endothelial cells, chondrocytes, alveolar macrophages, and smooth muscle cells. In tumors, AM expression was located in most of the nonsmall cell lung carcinomas and in half of the small cell lung carcinomas studied. These findings suggest that AM may play a broad role in respiratory homeostasis and lung carcinogenesis.
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There is continuous discussion about the optimal treatment for patients with inoperable non small cell lung cancer. This is because chemotherapy can only improve the quality of life in a fraction of treated patients while prolonging survival by a couple of weeks at best. The new cytostatic drug "vinorelbine" has been tested in this indication during the last years. The drug has reached the response rate of 16 to 30% when used as monotherapy. The phase II studies proved the combination of vinorelbine with cisplatin to be the most efficient one and this combination was picked up for phase III clinical trials. The clinical trial with the aims to verify published data on treatment efficacy, to assess adverse effects of treatment and to evaluate appropriateness for routine application has been made in the Czech Republic. The treatment schedule was as follows: cisplatin (Platidiam Lachema) in a dose of 80 mg/m2 on day 1, vinorelbine (Navelbine Pierre Fabre) in a dose of 30 mg/m2 on days 1 and 8. The whole cycle was repeated on day 22. The treatment was applied for 12 weeks. After that the efficacy of treatment was evaluated and only the patients with regression or stabilization of the disease continued the treatment. 44 (35%) partial remissions and 3 (2.3%) complete remissions were achieved in a group of 126 evaluable patients. The effect of treatment was evaluated as stable disease in 35 (27%) patients while the progression of disease occurred in 38 (30%) patients. The tolerance of treatment using effective antiemetic support (ondansetron or granisetron) was fairly good.