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Biomedical subjects

J Boëthius

Publications and source records attributed to J Boëthius.

At least 19 recordsLinked to original sources
PubMed1996

Polymeric controlled-release amsacrine chemotherapy in an experimental glioma model.

The purpose of this study was to fabricate and investigate amsacrine containing polymeric rods for use in interstitial chemotherapy of malignant glioma. Ethylene vinyl acetate copolymer (EVAc) rods containing 40% amsacrine (AMSA) were fabricated successfully with an extrusion method. In vitro kinetic studies revealed a high level of reproducibility of the production process. The release of AMSA showed a biphasic pattern consistent with a matrix-type controlled-release system with an initial more rapid release rate followed by a slower and more linear release phase. Release of AMSA was observed for over 6 months and the rods continue to release in a stable fashion. In vitro studies using rat glioma (RG2) in cell culture showed that cells treated with AMSA released from the rods were killed in a dose dependent manner indicating that AMSA incorporated into the polymer remained biologically active. In vivo studies of rats with single AMSA rods implanted five days after RG2 tumour implantation revealed histological evidence of an anti-tumour effect as well as an increased survival (p < 0.0003). The mean survival of the amsacrine treated rats was 78 days with 50% still remaining alive > 5 months after implantation. All control animals developed tumours and died within 15-19 days after tumour implantation (mean = 17 days). Amsacrine implanted animals showed no significant histological or clinical evidence of toxicity. We conclude that amsacrine containing EVAc rods can be safely and efficaciously use against the RG2 experimental glioma in a rat model and warrant further investigation.

Amsacrine↗
PubMed1987

Does successful interferon treatment of tumor patients require life-long treatment?

Case histories of 5 tumor patients treated with natural leukocyte interferon-alpha (IFN-alpha) are presented. One patient with juvenile laryngeal papillomatosis responded well to interferon treatment, but the disease recurred when therapy was withdrawn. Upon reinstitution of treatment, the patient once again responded well. Another patient with myelomatosis also responded well to interferon therapy and in this case, too, the tumor recurred when interferon treatment was withdrawn. Reinstitution of interferon therapy was, however, unsuccessful. One patient with generalized giant cell tumor of bone responded with regression after more than 5 years of interferon treatment. Another patient with pulmonary osteosarcoma metastases, having received irradiation and interferon combination therapy followed by sole interferon treatment, responded well with a lasting stationary radiogram after 6 years of interferon treatment. One patient with malignant glioma, showing signs of tumor growth during the first few months of interferon therapy, eventually responded, and became disease-free after 6 years. The latter 3 patients are continuously receiving interferon therapy although more than 5 years have elapsed since their interferon therapy was initiated. It is suggested that interferon therapy for malignant tumors be given for life (or to progression of disease) in responding patients. Such a concept entails biological implications for interferon therapy in general and for antitumor action of interferons in particular. Other possible clinical schedules should only be constructed within the framework of controlled clinical trials.

Adult↗
PubMed1981

Head fixation device for reproducible position alignment in transmission CT and positron emission tomography.

A head-positioning device allowing accurate position transference between computed tomography and positron emission tomography is described. A base plate is fixed to the patient's head through either an individual mold or screws into the calvarium. This base plate fits onto the headholders of the two devices, thus ensuring that scans are taken at the same level. Using the regular software, the coordinates of an anatomic structure may be determined and transferred between the two images.

Humans↗
PubMed1981

A study of glucocorticoid receptors in intracranial tumors.

Tissue samples from 20 patients with various intracranial tumors and one case of cerebral contusion were analyzed for the cytosolic glucocorticoid-receptor concentration using isoelectric focusing in slabs of polyacrylamide gel. It is pointed out that the clinical response to dexamethasone in brain edema associated with various intracranial lesions is, to some extent, parallel to the glucocorticoid-receptor concentration in these tumors. The findings in this investigation suggest that the cytosolic glucocorticoid receptor might be responsible for the initiation of a series of biochemical effects of steroids affecting brain edema. It is possible that the first step in eliciting a beneficial clinical response to dexamethasone in patients with brain tumors is the formation of a steroid-receptor complex in the peripheral parts of the tumor.

Adolescent↗
PubMed1980

Head fixation system for integration of radiodiagnostic and therapeutic procedures.

A head fixation system is described enabling exact transfer of positions between neuroradiological and therapeutic procedures. The key item of the system is a base plate that is rigidly attached to the patient's head, either by a plastic mould or screws onto the calvarium. The base plate may easily and accurately be attached to diagnostic or therapeutic units. Coordinates of target points in the various units are directly related through the exact application of the base plate. Procedures for the exact comparison of spatial information have been worked out. The system has been used for diagnostic procedures such as plain skull radiography, cerebral angiography, CT scanning, position emission tomography, and gamma camera examinations, as well as for therapeutic procedures such as stereotaxic biopsy and radiation treatment.

Head↗
PubMed1980

Gammathalamotomy in intractable pain.

Thalamotomy aiming at the CM-Pf complex and using stereotactic gamma irradiation has been performed in a series of 52 patients with severe pain due to malignancy. Lesions were produced either contra- or ipsilaterally to the side of the pain as well as bilaterally. Eight patients experienced good pain relief, 18 had moderate relief, and in 24 the operation did not significantly influence the pain. A second operation following recurrence of pain was rarely of value. There was a tendency towards more efficient relief of pain located in the face or in the arm and shoulder than of pain in the lower part of the body. Although contralateral lesions seem to be most effective, ipsilateral operations may also give some relief. The best results were obtained when the lesions were placed close to the wall of the third ventricle and at the level of the posterior commissure. Postmortem examination of 21 brains disclosed that the mean error in the placing of the lesions was about 1 mm. It is concluded that medial thalamotomy may be tried as a last resort in the treatment of cancer pain in selected patients with a short life expectancy.

Aged↗
PubMed1980

CT localization of stereotactic surgery.

A stereotactic system is described. It is built around a baseplate which is fastened to the head of the patient and to various diagnostic and therapeutic modalities. In principle this system can function as an interface between most diagnostic (CT scanners, PET scanners, conventional X-ray instrumentation for angiograms and pneumoencephalograms) and therapeutic (stereotactic instruments, linear accelerators) instruments. It has been in practical use since 1976 and used in a number of 'diagnostic-therapeutic' combinations.

Biopsy↗
PubMed1980

DNA distribution in various parts of malignant gliomas assayed on stereotactic biopsies.

The study concerns the relation between the computerized tomogram, histopathology and DNA distribution in gliomas. The investigation was performed on stereotactic biopsies, which enabled the comparison to be made on a point-to-point basis. No clear-cut relation was found between histopathological grading and DNA distribution. In 1 patient diploid and aneuploid tissue was found in different parts of the tumor. In this case the difference in ploidy was mirrored by differences in histopathological grading and gross morphology as indicated by the CT scan.

Biopsy↗
PubMed1980

Stereotaxic computerized tomography with a GE 8800 scanner.

A stereotaxic system is described that uses computerized tomography scanning for target localization. This system is unique in that the sterotaxic localization may be carried out using the scanner computer without the addition of any extra software. The hardware of the system is built up around a base plate which is fastened to the scanner's patient table. The head is positioned and fixed to the base plate with aluminum bars, which are fixed to the calvaria with screws. Various stereotaxic devices may be fastened to the base plate. The system has been in clinical use for 4 months at the time of writing. Its main application has been in tumor biopsies, but it has also been used for functional operations.

Humans↗
PubMed1978

Stereotactic biopsies and computer tomography in gliomas.

This study was carried out in order to obtain data on the relation between tumour structures seen in computer tomograms and the corresponding histopathology and cytology. Nine consecutive patients were studied, and stereotactic biopsies were obtained from sites determined on contrast enhanced computer tomograms. Biopsies were obtained from tumour areas with high and low contrast uptake and from the low attenuating areas surrounding the tumours. The results indicated a close correlation between the microscopical morphology of gliomas and the pattern of the computer tomogram. Biopsy samples from low-uptake central areas contained tumour tissues, necrotic tissue, and in one case a cyst. Biopsies from high-uptake areas typically contained tumour tissue, whereas biopsies from low-uptake surrounding areas contained oedematous non-tumour tissue. For tumour diagnosis biopsies should be obtained from both low and high attenuating tumour areas.

Aged↗
PubMed1978

Percutaneous central gray stimulation for cancer pain.

Electrical stimulation of the periventricular and periaqueductal gray matter via a percutaneous electrode appears to be a useful method for relieving cancer pain with midline and bilateral distribution. Due to the nondestructive character and the minor surgical risks involved in this procedure it may be tried before considering bilateral cordotomy or myelotomy. A possible mechanism of action or at least a contributive factor to the pain relief is the activation of endorphins.

Brain↗
PubMed1978

Stereotactic computer tomography for biopsy of gliomas.

A technique is introduced enabling automatic transfer of coordinates obtained at computer tomography into a stereotactic system previously applied in biopsies of brain lesions. Four to five biopsies from different parts of gliomas were taken to compare the structures demonstrated on computer tomography with the microscopic appearances. Of 45 biopsies in 13 patients, 36 were predicted correctly. This also served as an attempt to classify gliomas on the basis of their appearance in the CT image.

Adolescent↗