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Biomedical subjects

B Forsberg

Publications and source records attributed to B Forsberg.

At least 55 records · Page 3Linked to original sources
PubMed1987

Radiation exposure to personnel in departments of gynaecologic oncology in Sweden.

Radium-226 and cesium-137 are used at six departments of gynaecologic oncology in Sweden. A survey of radiation exposure (dose equivalents) to the personnel is reported. The measurements were performed with TL dosemeters. From dose distribution measurements, the dose equivalents in different parts of the body, related to different working procedures, were determined. Effective dose equivalents and collective dose equivalents were also estimated. The estimated collective dose equivalent for this category of personnel in Sweden was 1.3 manSv. The effective dose equivalent was less than the dose equivalent measured with dosemeters worn on the chest, and was less than half the annual limit set by ICRP.

Brachytherapy↗
PubMed1985

Narrowing of the dental pulp chamber in patients with renal diseases.

Narrowing of the dental pulp chamber was studied radiologically in fifty one patients with renal diseases. Two thirds of the patients were suffering from terminal uremia and were treated either by renal transplantation or with hemodialysis. The remaining patients were nonuremic and were treated with immunosuppressants because of progressive renal disease. There were significantly more patients with narrowing of the dental pulp chamber among the transplant patients than among the other patients. The transplantations included the use of higher doses of corticosteroids than the other treatments. As the median dose of corticosteroids was higher and total plasma steroid clearance was lower in the patients with narrowing of the dental pulp chamber than in the other patients, the amount of this drug received and its pharmacokinetics seemed to be an essential factor in the initiation of narrowing of the dental pulp chamber.

Adolescent↗
PubMed1985

Temperature and vascular stability in hemodialysis.

The temperature of the blood returning from an extracorporeal circuit may influence the vascular stability. Mean arterial blood pressure, heart rate and the temperature in the in-and outlet lines for blood and dialysis fluid of the dialyzer (TBa, TBv, TDi and TDo) were continuously measured in 8 patients suffering from vascular instability during standard dialysis. The TBv was adjusted to 37, 36 and 35 degrees C at the start of dialysis by manipulating TDi. The patients were studied two times at each temperature level during a 4-hour dialysis. At the start of dialysis TBa was 35.7 +/- 0.3 degrees C. The patient's mean arterial blood pressure and heart rate decreased and increased, respectively, continuously during TBv 37 and 36 degrees C experiments, but were fairly stable at an TBv of 35 degrees C. The standard TDi of 37 degrees C should be abandoned for a temperature which is similar to TBa (35.7 degrees C) to avoid the vascular effects of heating or cooling the blood in the extracorporeal system.

Adult↗
PubMed1985

Observations during long-term plasma exchange in primary biliary cirrhosis.

Plasma exchange was performed weekly during 6 months in two patients with symptomatic primary biliary cirrhosis. At the end of the treatment period improvement of liver demethylating capacity was noted, along with reduced C3 activation and a decrease in serum concentrations of IgM and procollagen III aminopeptide. Serum concentrations of aminotransferases, alkaline phosphatases, and anti-mitochondrial antibodies were not affected. These data suggest that long-term plasma exchange may improve liver function and possibly retard the progression of fibrosis in primary biliary cirrhosis.

Aged↗
PubMed1984

Dimethylsulfoxide increases the survival and lysosomal stability of mouse peritoneal macrophages exposed to low-LET ionizing radiation and/or ionic iron in culture.

Reactive oxygen-derived free radicals form excessively during irradiation of biological structures, but also normally in many cellular oxidative processes, albeit in small amounts. Unless scavenged by protective mechanisms, such radicals may induce peroxidation of polyunsaturated fatty acids resulting in membrane damage. The process may be catalysed to a considerable extent by transitional metals with the capacity to form redox systems, such as Fe3+ in equilibrium Fe2+. In the present study, it is shown that radiation by X-rays and/or exposure to ionic iron (Fe3+) causes decreased survival in parallel with lysosomal labilization of cultured mouse peritoneal macrophages (MPMs). The latter event was demonstrated as a reduced capacity of lysosomes in living MPMs to retain acridine orange during photo-oxidative stress caused by continuous exposure to blue light of short wavelength. The effects of X-irradiation, and/or lysosomal iron-loading, could be counteracted by the addition of the .OH-scavenging drug dimethylsulfoxide (DMSO) to the cell culture medium. The findings suggest that X-irradiation may damage certain sensitive G0 cells, such as Kupffer cells, serous cells of salivary glands and old macrophages, which normally have substantial concentrations of metals within their vacuolar apparatus, possibly by lysosomal damage involving .OH-mediated lipid peroxidation.

Acridine Orange↗
PubMed1984

Radiation effects on mast cells: secretory ability, histamine release and recovery, and cell number.

We studied the effects of irradiation with a single fraction of high-energy electrons, in the absorbed dose range used in radiotherapy, on features related to the rat mesenteric mast-cell (MC) population. Such features were energy dispersive X-ray microanalysis for zinc, light and transmission electron microscopic changes, histamine content, and secretory ability of MCs when exposed to the potent secretagogue 48/80. The observation period was 14 days. Also studied were the effects of radiation on the number and histamine content of free peritoneal MCs. Irradiation-induced decrease in histamine content was delayed for at least two days and the rate of subsequent recovery of mesenteric histamine was approximately 70% below normal. This was corroborated by the findings of necrotic and fragmented mesenteric MCs during the entire experimental period. Fibroblasts and macrophages phagocytosed groups of MC granules as well as individual MC granules. A fraction of the extruded MC granules retained an almost normal appearance. This suggests that they were solubilized unduly slow presumably because the irradiation destroyed the mechanisms and enzymes which normally degrade the heparin-protein granule matrix and its heparin. Moreover, the irradiation suppressed the secretory ability of mesenteric MCs and significantly reduced the number of free peritoneal MCs. The findings indicate that the MC is a remarkably radiosensitive connective-tissue cell.

Animals↗
PubMed1983

Malignant hypertension and HLA antigens.

Thirty-two patients with malignant hypertension and terminal uremia and a group of 1263 healthy blood donors were studied regarding the incidence of different HLA antigens. HLA-Bw35; Cw4 antigens were found to be significantly more frequent in the group of patients with malignant hypertension than in the group of healthy individuals. The frequency of HLA-Bw35 in a group of 60 non-uremic patients with biopsy-proven glomerulonephritis and without malignant hypertension was also studied and found equal to the group of healthy blood donors. There was no overrepresentation of IgA nephritis among the HLA-Bw35 positive patients with glomerulonephritis, but advanced vascular lesions were more common among these than among patients with other HLA antigens.

Glomerulonephritis↗
PubMed1981

Experimental limitations in microdosimetry measurements using the variance technique.

Microdosimetry measurements give information about the energy imparted to a volume of given size. With the most frequent method only data for object sizes above 0.2 micrograms are obtainable. Although restricted to the dose mean values, the variance technique can, however, be applied to objects sizes an order of magnitude less. In this report some limiting parameters for this technique are discussed and results down to about 20 nm in a 60Co gamma-ray beam are reported. the resulting data exceed earlier reported values at objects size below 0.1 microgram, but are in good agreement for larger object sizes.

Analysis of Variance↗
PubMed1979

Characterization of highly purified native streptokinase and altered streptokinase after alkaline treatment.

Physical and chemical data are reported for highly purified native streptokinase (staphylokinase, EC 3.4.99.22) (Kabikinase) and streptokinase treated with an alkaline agent (altered streptokinase). The mol. wts. were similar and were determined to be 50 200 by sedimentation equilibrium methods, polyacrylamide gradient gel electrophoresis and sodium dodecylsulphate-polyacrylamide gel electrophoresis. The sedimentation coefficient so20,w of native and altered streptokinase was found to be 3.37 S. The frictional ratio and the absorptivity (A1%1cm) at 280 nm of native streptokinase was found to be 1.29 and 7.5, respectively. Native streptokinase showed essentially a single band in the isoelectro-focusing pattern (pI 5.2), while altered streptokinase showed at least two separate bands. Polyacrylamide gel electrophoresis in the presence of Triton X-100 exhibited one band for native streptokinase but altered streptokinase showd two bands. At pH 12 the biological and immunological activity of streptokinase was markedly decreased in a time-dependent reaction. The amino-terminal amino acid of the two streptokinase forms was isoleucine and the carboxyl-terminal amino acid of native streptokinase was tyrosine. Peptide analysis showed that some peptides in altered streptokinase exhibited higher mobility compared to native streptokinase. The data suggest that streptokinase undergoes a conformational change when incubated in alkaline media, but no simultaneous loss of peptides was observed.

Amino Acids↗
PubMed1979

Glomerulonephritis and exposure to organic solvents. A case-control study.

Fifty patients with biopsy-proven glomerulonephritis and 100 sex- and age-matched controls (50 patients each with non-glomerular renal disease or acute appendicitis) were asked by questionnaire and a telephone interview whether they had been exposed to organic solvents. The questioning and the evaluation of the exposure, if any, was made without knowing the diagnosis of the interviewee. Fifty per cent of the patients with glomerulonephritis reported more than slight exposure, but only 20% of the controls. Exposure to organic solvents may often play a role in the causation of glomerulonephritis.

Adolescent↗
PubMed1978

Dose distribution around a new flexible afterloading applicator.

A new afterloading applicatory, together with a computer program, is described. A comparison of the calculated and measured dose distribution around different applicators shows that in the future the described computer program can be used. The development of the new applicator and the computer program increases the flexibility of possible dose distribution.

Cesium Radioisotopes↗
PubMed1978

Dose distribution in 42 MV roentgen irradiation of cervical carcinoma.

The dose distribution obtained with two different techniques for external irradiation of cervical carcinoma is described. The dose to the central area is somewhat higher with the multiple beam technique compared with the newly introduced shielding block technique. The difference between the calculated CRE values for the two techniques is small. When the shielding block is not placed over the area corresponding to the position of the applicators from the previous intracavitary treatment the considerable difference in absorbed dose between the two techniques does not correspond to the difference in the calculated CRE values. A comparison of the relative distributions laterally, in total dose and CRE, shows that for central volumes the relative CRE is much higher than the relative dose, when the normalization is made at the pelvic wall.

Absorption↗