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Biomedical subjects

M Ortiz

Publications and source records attributed to M Ortiz.

At least 73 records · Page 4Linked to original sources
PubMed1999

Sequence variations in the Boophilus microplus Bm86 locus and implications for immunoprotection in cattle vaccinated with this antigen.

Cattle tick infestations constitute a major problem for the cattle industry in tropical and subtropical regions of the world. Traditional control methods have been only partially successful, hampered by the selection of chemical-resistant tick populations. The Boophilus microplus Bm86 protein was isolated from tick gut epithelial cells and shown to induce a protective response against tick infestations in vaccinated cattle. Vaccine preparations including the recombinant Bm86 are used to control cattle tick infestations in the field as an alternative measure to reduce the losses produced by this ectoparasite. The principle for the immunological control of tick infestations relies on a polyclonal antibody response against the target antigen and, therefore, should be difficult to select for tick-resistant populations. However, sequence variations in the Bm86 locus, among other factors, could affect the effectiveness of Bm86-containing vaccines. In the present study we have addressed this issue, employing data obtained with B. microplus strains from Australia, Mexico, Cuba, Argentina and Venezuela. The results showed a tendency in the inverse correlation between the efficacy of the vaccination with Bm86 and the sequence variations in the Bm86 locus (R2 = 0.7). The mutation fixation index in the Bm86 locus was calculated and shown to be between 0.02 and 0.1 amino acids per year. Possible implications of these findings for the immunoprotection of cattle against tick infestations employing the Bm86 antigen are discussed.

Amino Acid Sequence↗
PubMed1999

[A possibility of central diffusion during stellate ganglion blockade: "the sheath of the spinal rachidian nerve"].

Stellate ganglion block is a common treatment for neuropathic pain. The technique is not without potentially severe complications when a paratracheal approach is used. A 33-year-old woman complained of atypical facial pain of 15 years' duration with pain intensity of 6 to 8 on a visual analog scale and no pain-free periods upon use of inadequate analgesia. One minute after performing a second stellate ganglion block the patient showed signs of apnea and paralysis of the upper extremities and face, with no involvement of oculomotor muscles or the lower extremities, and no loss of consciousness. Assisted ventilation was started. Signs and symptoms resolved fully after 15 minutes. A few days later, the patient reported having perceived paresthesia in the affected zone during the procedure. Central spread of a portion of local anesthetic by way of the spinal nerve sheath toward the subarachnoid space may cause partial cervical and basal nuclear blockade. Signs would be apnea, involvement of the upper extremities and facial muscles, although paresthesia during the injection is the only evidence supporting this hypothesis. Bone contact and negative aspiration while performing a stellate ganglion block do not guarantee avoidance of complications.

Adult↗
PubMed1998

C/EBPepsilon is a myeloid-specific activator of cytokine, chemokine, and macrophage-colony-stimulating factor receptor genes.

C/EBPepsilon is a member of the CCAAT/enhancer binding protein family of basic region/leucine zipper transcriptional activators. The C/EBPepsilon protein is highly conserved between rodents and humans, and its domain structure is very similar to C/EBPalpha. In mice C/EBPepsilon mRNA is only detected in hematopoietic tissues, including embryonic liver and adult bone marrow and spleen. Within the hematopoietic system, C/EBPepsilon is expressed primarily in myeloid cells, including promyelocytes, myelomonocytes, and their differentiated progeny. To identify potential functions of C/EBPepsilon, cell lines over-expressing the C/EBPepsilon protein were generated in the P388 lymphoblastic cell line. In contrast to the parental cell line, C/EBPepsilon-expressing cell lines displayed lipopolysaccharide-inducible expression of the interleukin-6 and monocyte chemoattractant protein 1 (MCP-1) genes as well as elevated basal expression of the MIP-1alpha and MIP-1beta chemokine genes. In the EML-C1 hematopoietic stem cell line, C/EBPepsilon mRNA levels increased as the cells progressed along the myeloid lineage, just preceding activation of the gene encoding the receptor for macrophage-colony-stimulating factor (M-CSFR). M-CSFR expression was stimulated in C/EBPepsilon-expressing P388 cell lines, when compared with either the parental P388 cells or P388 cell lines expressing either C/EBPalpha or C/EBPbeta. These results suggest that C/EBPepsilon may be an important regulator of differentiation of a subset of myeloid cell types and may also participate in the regulation of cytokine gene expression in mature cells.

Amino Acid Sequence↗
PubMed1998

[Subtyping panic disorders according to their symptoms].

BACKGROUND: Panic disorder (PD) is a common illness associated with high levels of disability and with a high utilisation of non-psychiatric health services which is inefficient in most cases. A better understanding of the clinical subtyping of PD may improve diagnosis both in psychiatric and medical settings. The present study is aimed at assessing the frequency, factorial grouping and comorbidity of PD symptoms in a naturalistic sample of patients. PATIENTS AND METHODS: All consecutive cases of PD (n = 442) who contacted with two outpatient clinics in Barcelona (Spain) were assessed by two experienced interviewers. Assessment instrument included SCID-UP-R interview and inventory of panic symptoms based on DSM-III-R. RESULTS: Palpitations (86.7%), shortness of breath (76.5%), fear of dying (69.9%) and dizziness (63.6%) were the most frequent and intense symptoms reported by the PD patients. The principal component analysis revealed four factors which explained the 56% of the variancel "cardiorespiratory" (23.2%), "depersonalization-derealization" (15.8%), "vestibular" (10%) and "mixed" (7%). CONCLUSIONS: The frequency of presentation of symptoms was similar to other studies. However some disimilarities appeared that may be attributed to transcultural differences as well as terminological problems and the range of symptoms assessed. Factors found in the present study support the clinical subtyping of PD in 3 groups characterised by cardiorespiratory symptoms and fear of dying, cognitive symptoms (depersonalization-derealization) and vestibular symptoms such as dizziness and faintness.

Adult↗
PubMed1998

Immunohistochemical detection of ribosomal transcription factor UBF: diagnostic value in malignant specimens.

The nucleolar organizer regions (NORs) of human chromosome can be identified in interphase and mitotic cells by localization of some intrinsic components such as the associated enzyme RNA polymerase I. A new sensitive staining method for NORs is described using a specific antibody to the ribosomal transcription factor UBF. By indirect immunofluorescence and enzyme-labelling methods, NORs stained in benign and malignant cells from a variety of tissues with monospecific anti-UBF serum showed significant morphological differences which correlated well with histopathological evaluation. The number of NORs per cell in malignant preparations increased significantly. Furthermore, the staining of a NOR protein component such as UBF appears to be as sensitive as the silver-staining technique (AgNOR) and might be a better alternative for detecting ribosomal activity in malignant tissues.

Biomarkers, Tumor↗
PubMed1998

Protection against Boophilus annulatus infestations in cattle vaccinated with the B. microplus Bm86-containing vaccine Gavac. off.

Tick infestations by Boophilus spp. constitute a major problem for the cattle industry in tropical and subtropical areas of the world. The use of traditional control methods has been only partially successful and tick infestations remain a serious problem. Recently, the gut antigen Bm86 was isolated from B. microplus. Recombinant preparations of this antigen have been used in vaccines for the control of B. microplus infestations. However, in several regions of the world, B. microplus coexists with other Boophilus species, mainly B. annulatus and B. decoloratus. Therefore, there is a need for the simultaneous control of infestations by different Boophilus species. To test the capacity of the P. pastoris-derived Bm86 antigen preparation (Gavac, Heber Biotec S.A., Havana) to control B. annulatus infestations, controlled experiments were conducted in Mexico and Iran. Cattle were vaccinated with Gavac or not vaccinated and then artificially infested with B. annulatus larvae. The results showed for the first time a high protection efficacy (> 99.9%) of Gavac in the control of B. annulatus infestations. These results support the application of Bm86-containing vaccines for the control of Boophilus spp. infestations.

Animals↗
PubMed1998

Role of fibroblast growth factors and their receptors in mouse primordial germ cell growth.

Primordial germ cells (PGCs) are the embryonic progenitors of mature germ cells. During their proliferative stage, murine PGCs may be transiently cultured on mitotically inactive feeder layers. This culture system has permitted identification of several growth factors active toward PGCs. We and others have previously identified basic fibroblast growth factor (bFGF) as a powerful mitogen in this system. Here we characterize some of the functions of bFGF in PGC culture. Our data demonstrate that fibroblast growth factor (FGF) receptors I and II are present in the developing gonad and are consistent with expression of these receptors by PGCs. Moreover, PGCs can bind radiolabeled bFGF in vitro, demonstrating that the factor can act directly on these cells. While mitotic PGCs of either sex are shown to bind radiolabeled bFGF, oogonia that are undergoing meiotic arrest exhibit reduced bFGF binding, indicating potential developmental regulation of an FGF receptor.

Animals↗
PubMed1998

Semiology and subtyping of panic disorders.

To date, the quantitative psychopathology of panic disorder (PD) has been less well studied than that of other psychiatric conditions such as schizophrenia or major depression. The aim of the present study was to assess the frequency and factorial grouping of symptoms in a naturalistic sample of PD patients. A total of 274 consecutive cases of PD who contacted an out-patient clinic in Barcelona, Spain were assessed by two experienced interviewers. The assessment instruments included the Structured Clinical Interview for DSM-III-R Upjohn version (SCID-UP-R) and an inventory of panic attack symptoms based on DSM-III-R. Of the patients who presented at the unit during the assessment period, 8.5% presented with PD. Palpitations, shortness of breath, fear of dying and dizziness were the most frequent and intense symptoms reported by the PD patients. Principal-component analysis revealed four factors which accounted for 57% of the variance, including 'cardiorespiratory' (26.1%) and 'vestibular' (15.1%) factors, and two additional factors with mixed symptoms. The frequency of presentation of symptoms was similar to that reported in other studies. However, some discrepancies were observed that may be attributed to transcultural differences as well as to terminological problems and the range of symptoms assessed. These factors may also explain some of the differences found in factor analysis groupings in previous studies. Our findings support the symptom subtyping of PD.

Adolescent↗
PubMed1998

Characterization of cry genes in a Mexican Bacillus thuringiensis strain collection.

Mexico is located in a transition zone between the Nearctic and Neotropical biogeographical regions and contains a rich and unique biodiversity. A total of 496 Bacillus thuringiensis strains were isolated from 503 soil samples collected from the five macroregions of the country. The characterization of the strain collection provided useful information on the ecological patterns of distribution of B. thuringiensis and opportunities for the selection of strains to develop novel bioinsecticidal products. The analysis of the strains was based on multiplex PCR with novel general and specific primers that could detect the cry1, cry3, cry5, cry7, cry8, cry9, cry11, cry12, cry13, cry14, cry21, and cyt genes. The proteins belonging to the Cry1 and Cry9 groups are toxic for lepidopteran insects. The Cry3, Cry7, and Cry8 proteins are active against coleopteran insects. The Cry5, Cry12, Cry13, and Cry14 proteins are nematocidal. The Cry11, Cry21, and Cyt proteins are toxic for dipteran insects. Six pairs of general primers are used in this method. Strains for which unique PCR product profiles were obtained with the general primers were further characterized by additional PCRs with specific primers. Strains containing cry1 genes were the most abundant in our collection (49.5%). Thirty-three different cry1-type profiles were identified. B. thuringiensis strains harboring cry3 genes represented 21.5% of the strains, and 7.9% of the strains contained cry11 and cyt genes. cry7, cry8, and cry9 genes were found in 0.6, 2.4, and 2.6% of the strains, respectively. No strains carrying cry5, cry12, cry13, cry14, or cry21 genes were found. Finally, 14% of the strains did not give any PCR product and did not react with any polyclonal antisera. Our results indicate the presence of strains that may harbor potentially novel Cry proteins as well as strains with combinations of less frequently observed cry genes.

Animals↗
PubMed1998

Organization of an umbilical cord blood transplant program.

The development of the human umbilical cord blood transplants with hematopoietic repopulating cells has enabled some problems associated with bone marrow transplants to be solved. Frozen umbilical cord blood banks should facilitate the finding of suitable stem cell donors. However, further experience is necessary to develop the optimal method for collection, separation, storage and cryopreservation of umbilical cord blood. We report our experience in the organization of a Cord Blood Bank.

Blood Banks↗
PubMed1998

[Implantable defibrillators in the management of malignant ventricular tachyarrhythmias. Experience at the Arrhythmia National Center].

BACKGROUND: Implantable defibrillators are the most effective means to prevent sudden death in patients with malignant ventricular tachyarrhythmias. The availability of this type of devices is limited in Chile, due to their high price. AIM: To report the first patients treated with implantable defibrillators in our hospital. PATIENTS AND METHODS: Nine males and one female aged 13 to 65 years old are reported. Three presented with ventricular fibrillation (presenting out of the hospital in three) and the rest had ventricular tachycardia resistant to drugs or radiofrequency ablation. RESULTS: All implants were performed using intracardiac electrodes. The generator was implanted in the pectoral region in nine and in the abdomen in one. A successful defibrillation was obtained with less than 15 J in four patients, with 20 J in three and with 24 J in three. There were no complications during the procedure. After a 12 months follow up, four patients have been treated by the implantable device. One of these subjects had a ventricular fibrillation in two occasions. One patient died of a bronchopneumonia two years after the implant. CONCLUSIONS: Implantable defibrillators are an effective therapy for the treatment of malignant ventricular arrhythmias with a high risk of sudden death.

Adolescent↗
PubMed1998

[Sudden death due to recuperated ventricular fibrillation: Brugada syndrome?].

We report a 47 years old male who was recuperated from a sudden death, and in whom the cardiological assessment showed a right bundle branch block and a fluctuating ST segment elevation V1 to V3. During the electrophysiological study, a polymorphic tachycardia and a ventricular fibrillation were induced. Procainamide administration enhanced ST segment alterations in right precordial leads, and isoproterenol normalized the EKG. All these disturbances are similar to the condition described by Brugada brothers. The patient was treated with an internal implantable defibrillator, without the use of antiarrhythmic drugs and is well after four months of follow up.

Bundle-Branch Block↗
PubMed1997

The effect of valsartan on the angiotensin II pressor response in healthy normotensive male subjects.

OBJECTIVE: Valsartan is an oral antagonist of angiotensin II that competes with angiotensin II for the AT1-receptor and is being developed as an antihypertensive agent. This study assessed the ability of 80 mg valsartan to inhibit the pressor effect of exogenous angiotensin II in healthy normotensive men, first after a single dose and then after multiple doses once daily for 7 days. METHODS: This was a single-center, double-blind, placebo-controlled, randomized crossover study. Six healthy men underwent angiotensin II challenges to determine a suitable dose required to increase their systolic blood pressure by approximately 30 mm Hg. Each subject then received an 80 mg dose of valsartan or matching placebo. The inhibition of the angiotensin II pressor effect was determined by the systolic blood pressure response to repeated angiotensin II challenges at multiple time points. RESULTS: Systolic blood pressure responses to angiotensin II challenges after single and multiple doses of valsartan were significantly lower than placebo, indicating that valsartan blocked the blood pressure response to angiotensin II. The maximum blocking effect was observed within 2 to 3 hours. Mean data suggested that differences in effect between valsartan and placebo were similar after both single and multiple doses and persisted up to 24 hours after administration. The angiotensin II blocking effect was maintained up to this time, despite low plasma valsartan levels and minimal accumulation after multiple doses. CONCLUSION: Valsartan, 80 mg, is a potent angiotensin II antagonist with a rapid onset of action and persistent angiotensin II inhibition up to 24 hours. There is no attenuation of this effect after multiple doses.

Adult↗
PubMed1997

Stimulus responses and amyloid precursor protein processing in DAMI megakaryocytes.

Platelets, when released as anuclear cells by their precursor megakaryocytes, already carry soluble proteolytic fragments of the amyloid precursor protein (APP) within their alpha-granules and intact APP in the alpha-granule membranes. In response to activation signals elicited by physiologic stimuli such as thrombin, platelets release their granules' soluble contents and translocate granule membrane-bound proteins to the plasma membrane. Because platelets carry >90% of the circulation's APP, activated platelets have been implicated as origins of the beta-amyloid peptide fragment of APP (A beta), whose deposition in the cerebrovasculature is characteristic of Alzheimer's disease. We have therefore studied the APP contents and proteolytic processing in resting DAMI human megakaryocytic cells, along with the consequences of the activation of these cells by thrombin, comparing the results in each case to those with human platelets. Resting and PMA-differentiated DAMI cell contents were examined by Western blotting, immunoprecipitation, or metabolic labeling with sulfur 35-labeled methionine during culture, while plasma membrane-bound APP was evaluated by flow cytometry. Activation was followed by changes in cytoplasmic calcium concentration ((Ca++)in) and in membrane potential. Like platelets, DAMI cells exhibited a thrombin dose-dependent delta(Ca++)in, and membrane potential change; in contrast to the surface of a platelet, the surface of an agranular resting DAMI cell expresses granule-membrane proteins (APP and CD63) that appear on platelets only after activation. DAMI cell culture with 35S-labeled methionine confirmed that megakaryocytes synthesize large amounts of APP, of slightly higher molecular weight, and degrade their APP extensively before platelets are formed.

Amyloid beta-Protein Precursor↗
PubMed1997

Viral phenotype, antiretroviral resistance and clinical evolution in human immunodeficiency virus-infected children.

BACKGROUND: The syncytium-inducing (SI) viral phenotype and the emergence of viral strains resistant to zidovudine have been described in persons infected with HIV, and in some cases they have been associated with poor prognosis. METHODS: HIV isolates obtained from 37 HIV-infected children were analyzed to determine whether the SI viral phenotype and the mutation on the 215 position of the reverse transcriptase (M215) could be used as markers of disease progression. We performed peripheral blood coculture mononuclear cells, and we analyzed the induction of syncytia using the MT-2 cell line. The emergence of mutations on the 215 position was determined by PCR. RESULTS: We found a statistically significant association (P < 0.05) between SI viral phenotype and (1) recurrent serious bacterial infections, (2) absolute CD4+ cell counts <2 SD, (3) progression to AIDS and (4) death. Sixty percent of the children treated with zidovudine developed 215 mutant viral strains without statistically significant association with clinical or immunologic findings. The SI viral phenotype was statistically associated with the presence of the 215 mutation (P < 0.05). CONCLUSIONS: SI viral phenotype is a marker associated with a poor clinical and immunologic progression of the disease and it may facilitate the emergence of mutant strains in children treated with zidovudine.

Adolescent↗