Biomedical subjects
Publications and source records attributed to R Lippens.
High-dose treatment with dexamethasone led to reversible hepatomegaly with disturbance of liver function in three children. After withdrawal of dexamethasone, liver size and function returned to normal. These observations were compared with previously published data. The authors conclude that if this condition occurs, dexamethasone should be discontinued.
Choroid plexus carcinoma is a rare intracranial neoplasm, affecting mainly very young children. The most common site of origin is within one of the lateral ventricles. The diagnosis of choroid plexus carcinoma is based on histological examination. Frequently subarachnoid seeding occurs and investigation at diagnosis should include examination of the cerebrospinal fluid and magnetic resonance imaging of the spinal cord. Extraneural metastases are rare. Prognosis for long-term survival ameliorates. Total surgical resection of the tumor should be attempted. Both radiotherapy and chemotherapy are used as adjuvant therapies for primary tumors. No clear difference in effectiveness of these therapies could be found. However craniospinal irradiation seems to be more effective when leptomeningeal seeding is present.
The ROP2 protein of Toxoplasma gondii possesses immunological and biological properties which have led to its proposal as a vaccine candidate. To identify epitopes recognized by human T cells in the ROP2 antigen, we submitted the sequence of this protein to three reported T-cell epitope prediction algorithms. Three sequences that were predicted by all three methods were selected (sequences 197 to 216, 393 to 410, and 501 to 524), and the corresponding peptides were synthesized. The peptides were first tested in a proliferation assay with a DPw4-restricted, ROP2-specific human T-cell clone, and the peptide corresponding to residues 197 to 216 was shown to stimulate the T-cell clone. The three peptides were further tested in proliferation assays with peripheral blood mononuclear cells from a panel of T. gondii-seropositive and -seronegative individuals. We found that cells from a high proportion of the seropositive donors (64%) recognized at least one of the three peptides. The most frequently recognized ones were peptides 197 to 216 (45%) and 501 to 524 (36%). None of the seronegative donors responded to any peptide. These results show that the ROP2 antigen of T. gondii contains T-cell epitopes recognized by a high percentage of the immune population and further strengthen its potential as a vaccine candidate.
Echocardiograms of 47 children treated with doxorubicin in combination with other cytostatic agents in the period 1979-1984 were reviewed. The authors compared the first and the last echocardiographic registration of every individual patient, analysing the left ventricular dimensions and the shortening fraction which is the indicator of myocardial contractility. Statistical analysis revealed a significant dilation of the left ventricle with a decrease of contractility in the whole group of patients during the therapy. Seven out of 9 patients who had an abnormal shortening fraction at the last measurement died of malignancy. Three children, all in remission of their malignancy, developed a dilated cardiomyopathy that was fatal in two. The possibilities for prevention of this serious complication by means of serial echocardiography during treatment with anthracycline derivatives are discussed.
Three patients developed a Fanconi syndrome with impairment of glomerular function (endogenous creatinine clearance 30-60 ml/min per 1.73 m2) during and/or after treatment with ifosfamide according to the SIOP-MMT 84 protocol in which ifosfamide was given in a dose of 3000 mg/m2 every 4 weeks over a 10-month period. The need for early substitution therapy in patients with the Fanconi syndrome is stressed. The renal lesions in our patients were irreversible.
An immunogenic protein called P32 has been purified from Sauton zinc deficient culture filtrate of Mycobacterium bovis BCG using successively hydrophobic chromatography on Phenyl-Sepharose, ion exchange on DEAE-Sephacel and molecular sieving on Sephadex G-100. The final preparation was found to be homogeneous as based on several analyses. This P32 protein was a constituent of BCG cells grown in normal conditions. It represented about 3% of the soluble fraction of a cellular extract, and appeared as the major protein released in normal Sauton culture filtrate. This protein was found to have a molecular weight of 32,000 by SDS-polyacrylamide gel electrophoresis and in molecular sieving. Its amino acid composition showed an abundance of acidic amino acids (or their amides). The NH2-terminal amino acid sequence (6 amino acids) was determined. Purified P32 was tested by various crossed immunoelectrophoresis techniques, and was shown to belong to the antigen 85 complex in the reference system for BCG antigens. It was more precisely identified as antigen 85A. The protein antigen elicited a weak delayed hypersensitivity reaction in guinea pigs sensitized with heat-killed or living BCG. No delayed hypersensitivity reaction was observed in living BCG sensitized mice, however, it induced significant amounts of gamma interferon in cultured spleen cells from BCG-sensitized mice. Moreover, P32 either pure or as part of BCG soluble extract promoted substantial antibody levels when injected in rabbits.
A totally implanted system for central venous access--consisting of a subcutaneous injection port, connected to a silastic catheter positioned into the superior caval vein--has been utilised in 17 children with cancer treated by aggressive chemotherapy regimens. This preliminary study over a 1 1/2-year period suggests that such devices may represent an improvement over currently available techniques of prolonged venous access, and are suitable for children as well. The device has proved to be a reliable, safe, convenient and effective method for delivering drugs, antibiotics, blood products, nutritional and other intravenous fluids. In 3881 patient days no serious complications have occurred. The complications encountered must be considered as starting problems of this device in the paediatric age group. These problems have been solved. Continuous infusion therapy lasted up to 122 consecutive days without skin problems. The system has the advantage of simplicity of positioning, use and maintenance. It facilitates ambulatory anticancer treatment.
Somatosensory and brainstem auditory evoked potentials (SSEPs and BAEPs) provide sensitive measures of the central conduction functions of the auditory and somatosensory input systems at different levels of the central nervous system. The contribution of SSEPs and BAEPs in the primary diagnosis and follow-up of 26 children with infra- and supratentorial tumors were reviewed. The SSEPs, especially the specific complex, showed a latency increase in patients with supratentorial and brainstem mass lesions involving directly or distantly the somatosensory tracts. The BAEPs were sensitive for supratentorial pressure effects and for local and distant posterior fossa tumor effects. In the follow-up of children, evoked potentials offer a good method of detecting tumor recurrence, whereas neuroradiological procedures may be obscured by surgical or radiation artifacts.