Mapping of antigenic determinants of the T. cruzi hsp70 in chagasic and healthy individuals

In the present paper we describe the analysis of the immunological recognition by sera of healthy individuals and chagasic patients of the Trypanosoma cruzi heat shock 70 kDa protein. By a Falcon Assay Screening Test, using as antigen an ATP-agarose purified T. cruzi hsp70, it has been found that the sera of infected patients as well as of that of healthy individuals show reactivity against the hsp70 protein but that the reactivity of the sera of patients is in general significantly higher than that of healthy individuals. The analysis of the reactivity of the chagasic sera against a collection of peptides covering 92% of the protein has shown that more than 50% of the peptides gave a positive response but only against a few peptides did we observe high reactivity in a wide spectrum of sera. Only four peptides (numbers 9, 12, 14 and 47) were recognized by all sera tested with high reactivity values. The sera of healthy individuals also showed reactivity against a large percentage of peptides but with lower values. It was observed that particular peptides showing high reactivity against the sera of healthy donors also show high reactivity against patients' sera. However, the general pattern of reactivity against the peptides is different in chagasic and healthy sera. The immunodominant peptides map in the highly conserved as well as in the less conserved part of the hsp70 molecule. The 1/3 C-terminal, being the least conserved part of the molecule, seems to be the least immunogenic. Mapping of the epitopes led to the identification of particular immunogenic motifs within individual peptides.

[Clinical, epidemiologic, and microbiologic study of urinary infection in patients with renal transplant at a specialized center in Argentina]

Sixty-four patients were evaluated for urinary tract infection (UTI) during the first six months after renal transplantation. Eighty per cent received the allograft from a living, related donor and 37% were female. The median age was 33.8 years. All the patients received cefazolin as perioperative antibiotic prophylaxis. No prophylaxis was given during the bladder catheterization period, which had a median duration of 5.9 days. Nineteen per cent developed predisposing urological factors (PUF). The incidence of UTI was 41% and 15% of all these patients developed bacteremia from this source. UTI was observed in 50% of the patients without PUF between the 5th and 12th days post-transplantation, and these cases had been detected by the control urine culture performed when the bladder catheter was withdrawn. This group of patients accounted for 14% of all the patients. Recurrence was present in 42% of the patients with UTI (19% had reinfection, 4% relapse and 19% both). They were more frequent in patients with PUF than in the patients without; 78% vs. 24%, respectively (p < 0.05). The overall UTI incidence was also higher; 75% vs. 33%, respectively (p < 0.05). The same was observed for the median number of episodes (3 vs. 1). The organisms most frequently isolated were E. faecalis (21%). E. cloacae (17%), and E. coli (17%). Species prevalence differs from that of other reports, probably due to the different institutional antibiotic management. Since half of the UTI episodes suffered by patients without PUF were associated to bladder catheterization, there is a need to institute antibiotic prophylaxis in our center.

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.

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.

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.

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.

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.

Total craniopagus twins

The frequency of craniopagus twins is very low and so far only 32 cases have been reported in the literature. Most of authors give a frequency of 1 in 2.5 million births, although, since numerous cases are not reported, it is probable that the occurrence is greater than this figure indicates. A new case of conjoined twins by the head is presented.

[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.

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.

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.

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.