Pathogenesis of central nervous system lesions in visna: cell-mediated immunity and lymphocyte subsets in blood, brain and cerebrospinal fluid.

There are several indications that central nervous system (CNS) lesions in visna are immune-mediated and that cell-mediated immunity (CMI) may be of importance in the initiation of the lesions. To study the role of CMI in the pathogenesis of CNS lesions, five sheep were infected by intracerebral inoculation with visna virus and observed for 1 year. The following parameters were monitored at regular intervals: (1) neutralizing and ELISA antibodies; (2) visna virus-specific stimulation of lymphocytes from peripheral blood; (3) lymphocyte subpopulations in peripheral blood, cerebrospinal fluid (CSF) and brain at sacrifice. The CNS lesions were graded and compared with other parameters. The time course and titers of antibodies did not correlate with the severity of CNS lesions whereas the CMI did, indicating that CMI may play an important role in lesion development. The correlation of the number of CD8-positive cells in the CSF with the severity of lesions and the reversed ratio of CD4/CD8-positive cells in the diffusely infiltrated neuroparenchyma indicates that the CD8-positive T lymphocyte may be an important effector cell in the induction of CNS lesions.     

An alternative approach in the surgical treatment of infectious endocarditis. The fresh antibiotic-sterilized aortic valve homograft

Following the pioneering work of Ross and Barratt-Boyes, there is currently a strong evidence based on long-term follow-up data that valve homografts are the best valve substitutes in the aortic position. Currently there exists a renewed interest in the use of fresh and cryopreserved homografts as we know that homografts show a prolonged durability together with the lack of thromboembolic complications. Here we present the case histories of 3 patients undergoing aortic valve replacement by fresh homografts sterilized in antibiotic solution. The underlying pathology was infective endocarditis in all 3 patients, a disease that is considered the ideal indication for homograft implantation. Technical details at the time of implantation, their advantages with regard to other replacements devices and the whole process of procurement, manipulation and preservation are commented on.     

Serum analysis for potassium ions using a fibre optic sensor.

A fibre optic potassium ion sensor has been developed based on reflectance measurements of the pH-dependent chromogenic crown ether 'Takagi reagent' immobilized on the non-ionic polymeric resin Amberlite XAD2. The sensor response is in the 1.5-100 mM range with a detection limit of 0.25 mM K+. The selectivity factor over sodium is 20. The proposed sensor works with a reproducibility of +/- 0.8% at the 5 mM K+ level. Advantageous design features include ease of construction, simplicity of use, reversibility, short response time (approximately 1 min) and an optimum working pH range (7.0-8.0) for biological fluids. This optical sensor was applied successfully to the direct determination of potassium in human serum. Aqueous potassium standards containing 0.13 M NaCl and a buffer of pH 8 were used for calibration.     

A primary gastric Burkitt's lymphoma in a child]

We report a case of a primary gastric Burkitt's lymphoma in a 8-year-old child, which first symptoms were abdominal pain, dysphagia, melena and a constitutional syndrome. The differential characteristics of this case are its peculiar gastric infiltration and the existence of oesophageal extension, which is very infrequent among this kind of tumors.     

Intraoperative radiotherapy of upper abdominal tumours

Thirty patients with malignant tumours in the upper abdomen underwent surgery and intraoperalive radiation (IORT), using electron beam, to: the surgical bed, residual or unresected tumour. The technical aspects and results of this treatment are described. Renal, adrenal, bile duct and gastrointestinal tumours were treated. along with several other lesions. The surgical procedure consisted in 10 cases simply of exposure of the tumour for IORT and in 20 the tumour was resected. The TORT dose ranged from 10 to: 20 Gv. In 13 patients, external beam radiation was also given to: residual tumour or to: areas of high risk for recurrence. Chemotherapy was given to: 10 patients. Tolerance to: the combined treatment was acceptable; with few complications related to: IORT.The median follow-up and survival time 23 months (range 4-more than 70 months). Local tumour control rate (or tumour stabilisation) is 90%. Distant metastases developed in 19 patients (63%). The actuarial survival rate for the group projected at 70 months (maximum follow-up) is 37%. IORT in useful in the management of tumours arising in the upper abdominal organs, for palliation surgery or when resectability of the tumour is in doubt. Indications for IORT include patients with uncommon tumours of the upper abdomen who are not be candidates for standardised cancer treatment.Presented at the European Congress of Radiology, Vienna, September 15–20,1991     

Pulmonary embolism.

Pulmonary embolism (PE) is an important health problem and often a major clinical challenge, not only because of the low specificity of its clinical manifestations but also because of the increasing number of medical circumstances that are risk factors for this illness and the importance of early identification, since prompt and appropriate treatment can decrease mortality from this disease by about 25%. In recent years research on PE has been extensive, directed mainly at trying to determine and characterize its risk factors, establish new clinical probability algorithms, develop new diagnostic methods and put existing ones into perspective, seek new therapeutic approaches (pharmacological and non-pharmacological), and above all establish protocols that can guide the clinician from the stage of clinical suspicion to measures to prevent recurrence. It was the authors' aim to review the most significant literature on this subject, in order to produce a text that reflects the state of the art concerning PE and that can be used as a guide in the clinical approach to this pathology.     

Cast syndrome

The term cast syndrome is used to denote duodenal obstruction occurring after application of a corrective plaster cast to patients with scoliosis. We report a classical case in a 14-year-old female who required surgical intervention after conservative treatment failed. Six months later the patient had no further gastrointestinal symptoms. Clinical, radiological, and pathological details as well as the surgical treatment are described and discussed. Offprint requests to: M. E. Martín Hortigüela     

Low plasma zinc and androgen in insulin-dependent diabetes mellitus

Plasma zinc and pituitary and testicular hormone concentrations were measured in two groups of male adolescents. One group comprised insulin-dependent diabetes mellitus patients, aged 14-19 years; the other, as control, included 12 healthy youngsters aged 13-19 years. Plasma concentration of zinc, prolactin, testosterone, and dihydrotestosterone were lower in diabetics than in controls, whereas the ratios of androstenedione and androstenedione to testosterone + dihydrotestosterone were higher. Plasma FSH and LH were normal. These results suggest a diminished conversion of androstenedione to testosterone and relate zinc with the 17-beta-hydroxysteroid dehydrogenase enzyme activity.