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Biomedical subjects

M Soto

Publications and source records attributed to M Soto.

At least 19 recordsLinked to original sources
PubMed1992

Molecular characterization of a Leishmania donovani infantum antigen identified as histone H2A.

A Leishmania donovani infantum promastigote cDNA expression library was screened with a serum obtained from a dog naturally infected with this parasite. One of the positive clones obtained revealed nucleotide sequence similarities with the histone H2A genes from various organisms. Northern blot analyses and sequence data of three independently isolated cDNA clones indicated that the Leishmania H2A mRNAs are polyadenylated, as are the basal histone mRNAs of higher eukaryotes and the histone mRNAs of yeast. The analysis of the genomic distribution of the DNA coding for histone H2A suggested that, in L. d. infantum, there are at least four genes coding for the H2A protein. It is likely that there is a simultaneous expression of at least two of the H2A genes since differences in nucleotide sequence between two of the sequenced cDNAs were observed. Affinity-purified antibodies against the beta-galactosidase-fused H2A protein recognize specifically a Leishmania protein band with a molecular mass of 14 kDa.

Amino Acid Sequence↗
PubMed1992

Regulation of hsp70 expression in Trypanosoma cruzi by temperature and growth phase.

The steady-state level of the hsp70 mRNAs of Trypanosoma cruzi cultured at different temperatures and growth conditions has been analyzed by Northern blotting. We show that only one size class of hsp70 mRNA, of about 2.2 kb, is transcribed from the hsp70 cluster and that its transcription is constitutive at 28 degrees C. However, after a heat shock treatment at 37 degrees C for 2 h of logarithmically growing parasites, the abundance of the hsp70 mRNA increased about 4-fold. A similar increase was observed at 28 degrees C when the parasite culture reached the stationary phase of growth. On the other hand, a heat shock at 42 degrees C did not change the steady state level of the 2.2-kb size class of hsp70 mRNA. However, accumulation of transcripts of high molecular weight was detected when stationary growing parasites were cultured at 42 degrees C for 2 h. Also at 37 degrees C the steady state level of the alpha- and beta-tubulin mRNAs of logarithmically growing parasites exhibited a slight increase but only after a period of 24 h. Analysis by one-dimensional immunoblots of the Hsp70 levels showed that at 37 degrees C the abundance of the protein was 4-fold higher than at 28 degrees C. Immunoblots of high-resolution two-dimensional gel electrophoresis showed, moreover, that various isoforms of this protein are constitutively expressed at 28 degrees C and that some of them have a specific pattern of induction at 37 degrees C. We observed, moreover, that the heat shock induces the expression of a series of proteins while it causes repression of others.

Animals↗
PubMed1992

Characterization of a highly repeated interspersed DNA sequence of Trypanosoma cruzi: its potential use in diagnosis and strain classification.

In the present paper we report the characterization of a repetitive DNA sequence from the genome of the Maracay strain of Trypanosoma cruzi. The sequence is 1025 nucleotides long and represent about 7% of the total nuclear DNA of the parasite with a copy number of 1-2 x 10(4) copies per genome. It is also present in a high copy number in several strains of T. cruzi but absent from other trypanosomatids and from the human genome. The DNA sequence is interspersed and present on many chromosomes. We show that the different copies of this repeat present extensive endonuclease restriction polymorphisms. Using 2 conserved oligonucleotide primers derived from the repetitive sequence, together with the polymerase chain reaction technique, the presence of less than 1/30 of a single parasite can be readily detected by ethidium bromide staining.

Animals↗
PubMed1991

Responses of winkles digestive cells and their lysosomal system to environmental salinity changes.

After acclimation to 100, 75 and 50% of Sea Water (SW) external salinities, a significant reduction in MET (Mean Epithelial Thickness) and MDR (Mean Diverticular Radius) indicates a decrease in the digestive cell volume dependant on the lowering of environmental salinity. The interstitial connective tissue seems to be unable to osmoregulate and hence stand severe changes in cell size depending on external salinity. 50% SW acclimated periwinkles show a general pattern of general stress response (decreasing MET and MDR, and increasing ND -Numerical Density of lysosomes- and lysosomal size). A reduction in number and size of digestive lysosomes in winkles acclimated to 75% of Sea Water evidences the functioning of regulatory mechanism of digestive cell volume.

Animals↗
PubMed1990

Histochemistry and elemental composition of the stomach cells in Littorina littorea (L.).

The present work deals with the histochemical, histoenzymological and micro-analytical study of the stomach of Littorina Littorea (L.). The results suggest the existence of intracellular digestion within the stomach cells. Thus, the occurrence of lysosomes in the mid-cytoplasm of stomach cells has been revealed by demonstration beta-glucuronidase activity in cryostat sections of frozen tissues. Other enzymatic activities have been proved with the same tissues. Accordingly, the results on lipid and pigment histochemistry indicate a certain digestion in this cell type. Mucocytes show a protective role for the epithelium, their main secretions being acid MPS. The elemental composition of electron dense concretions from the stomach cells indicate the presence of very high amounts of iron associated to lower peaks for sulphur, phosphorous and other cations found as calcium, copper and zinc.

Animals↗
PubMed1989

Oral nifedipine vs oral clonidine in the treatment of urgent hypertension.

Fifty-one patients with urgent hypertension were treated in the emergency department with either oral nifedipine or oral clonidine in a randomized double-blind prospective study. Nifedipine was administered as a single dose of 20 mg. Clonidine was administered as an initial dose of 0.1 mg with hourly doses of 0.1 mg. Nifedipine was successful in reducing diastolic blood pressure in 83% of the patients within 45 minutes and in 96% of the patients within two hours, with a mean reduction in systolic blood pressure of 47 mm Hg and diastolic blood pressure of 29 mm Hg. Thirty percent of those who initially responded to nifedipine experienced a subsequent increase in diastolic blood pressure to pretreatment levels within three hours. Clonidine was successful in reducing diastolic blood pressure in 79% of the patients within four hours, with a mean reduction in systolic blood pressure of 51 mm Hg and diastolic blood pressure of 30 mm Hg. Our results indicate that both nifedipine and clonidine are safe and effective in the treatment of urgent hypertension. Nifedipine had a much more rapid onset of action with a greater initial success rate, and it was free from the sedative side effects of clonidine. We believe that either nifedipine or clonidine may be used as first-line therapy in the treatment of urgent hypertension.

Administration, Oral↗
PubMed1983

Pulmonary function following staphylococcal pneumonia in children.

Twenty three subjects with proven staphylococcal pneumonia (19 with empyema) were studied 12-25 years after the original infection. Clinical radiological, and lung function status and airway response to histamine inhalation was assessed. No clinical or radiological changes resulted from the original staphylococcal infection. No subject had physiological evidence of chronic lung disease and there was no evidence of an increased incidence of airways hyperreactivity.

Adolescent↗
PubMed1979

[Antibiotic treatment of pneumococcal meningitis (author's transl)].

Pneumococcal meningitis, which represents the third in frequency among the purulent forms of meningitis, continues to be, in spite of antibiotic therapy, a serious problem due to its high mortality rate, which reaches 50 per cent in patients of advanced age. The antibiotic treatment of choice is penicillin G, using chloramphenicol as the substitute antibiotic and the cephalosporins in other instances. This article is a review of the cases of pneumococcal meningitis which were admitted to our hospital in the period between 1969-1977, placing especial stress on the therapy followed. Our experience in the treatment of 28 patients affected with this condition indicates therapeutic success in 45 per cent of the cases treated with penicillin G, and a rate of 70 per cent using cephaloridine. In view of these results we believe that cephaloridine should be considered an important alternative antibiotic in the therapy of pneumococcal meningitis.

Adult↗
PubMed1979

An assessment of a system to monitor the activity of patients in a rehabilitation programme.

The need for an objective quantitative method of monitoring performance in the natural environment for use in a rehabilitation programme is discussed. A system of monitoring the number of steps taken has been developed for an amputee programme as a first attempt towards this goal. Instrumentation consists of an inexpensive foot switch, a storage unit and a retrieval unit. Early clinical experience indicates this system may be of value in the rehabilitation programme by (1) indicating low or unusual activity and alerting clinical staff to identify the cause. (2) Restricting the over-anxious patient when excessive activity is contra-indicated. (3) Identifying poor use of the prosthesis in the home environment. (4) Providing motivation for patients to set personal goals. (5) Acting as a base line for the evaluation of research and development of new techniques.

Activities of Daily Living↗
PubMed1978

Computerized axial tomography for the diagnosis of cerebral cysticercosis.

Computerized Axial Tomography (CAT) has proved extremely useful for the diagnosis of cerebral cysticercosis. The calcified small, multiple, and scattered cysts provide a typical image on CAT. The collection of non-calcified cysts in the subarachnoid spaces (racemose form) or in the ventricles may produce areas of low density similar to that of the cerebrospinal fluid. The dilatation of the ventricular system, extreme degrees of hydrocephalus, areas of cerebral atrophy, and other related changes induced by the cysts in the subarachnoid spaces are also clearly shown in the CAT. Four personal cases are reported.

Adult↗
PubMed1978

Biofeedback training of knee control in the above-knee amputee.

Learning to control a prosthetic knee is a difficult task for the above-knee amputee. A biofeedback training system was designed to help with this problem. The system was found to be useful with several aspects of knee control. Fifteen patients completed a biofeedback training program. Two of these patients did not benefit to the same degree as the other thirteen.

Aged↗
PubMed1976

Surgical management of tumours of the pineal region.

Tumours of the pineal region and posterior part of the third ventricle are rare in European and American series (0.5 to 1% of space-occupying lesions). Personal experience is usually limited and thus cooperative studies or critical reviews of reported cases are necessary to establish therapeutic criteria. We have studied 50 cases from our own material of more than 5,000 brain tumours and intracranial space-occupying lesions operated on during the last 30 years. Another 6 verified cases from Dr. F. Isamat, and more than 200 verified tumours from the literature are added. Histological distribution shows that 24% of the tumours in this locality are benign. The different surgical techniques fro reaching the pineal region are reviewed. The results of palliative operations, or partial removals together with radiotherapy, and total removals are presented in 200 verified cases (Table 1), as well as the results obtained by the different surgical approaches (Table 2). Finally, some conclusions are reached regarding the surgical management of these tumours. More than two thirds are radiosensitive, and in about 50 to 70% good results may be obtained with palliative operations and radiotherapy. The remainder of the pineal tumours (about 20%) should be treated by a direct surgical approach. Recent technical improvements and the use of the surgical microscope have reduced the mortality of pineal surgery and allow verification of the histological nature of the tumour in order to establish more rational treatment.

Brain Neoplasms↗