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Biomedical subjects

B Karlsson

Publications and source records attributed to B Karlsson.

At least 73 records · Page 4Linked to original sources
PubMed1994

Diseases and environmental contaminants in seals from the Baltic and the Swedish west coast.

Investigations have shown that Baltic grey seal (Halichoerus grypus) and ringed seal (Phoca hispida) suffer from a disease complex described as a primary lesion in the adrenals causing secondary reactions in various other organs. Studies on historical Baltic grey seal skull bone material show that the prevalence of affected animals started to increase after World War II. The disease complex explains the dramatic decrease in the Baltic grey and ringed seal population during the 1960s and 1970s and is believed to be caused by environmental pollutants. In 1988, about 60% of the harbor seal population (Phoca vitulina) along the Swedish west coast and in the southwestern part of the Baltic died in the PDV epizootic (Phocine Distemper Virus). Whether the course of the epizootic was altered by environmental pollutants is still an open question. Studies on historical harbor seal skull bone material from both the Baltic and the Swedish west coast show that the incidence of skull bone lesions has also increased in these populations since World War II, indicating the presence of unnatural stress factors. After the epizootic, the harbor seal populations both in the Baltic and along the Swedish west coast have increased in number. Chemical analysis of tissues has been performed on the three seal species collected in various areas of the Baltic and the Swedish west coast. The concentrations of 17 metals and non-metal elements, sDDT and PCBs, DDE and PCB methylsulfones, toxaphene, chlordanes, polybrominated diphenyl ethers, PCDDs and PCDFs have been determined in selected groups of seals in order to determine spatial, species and age variations in concentrations. Furthermore, healthy animals have been compared to diseased animals. Spatial variation was found mostly within the group of organohalogenated compounds, a group of contaminants where a strong covariation between the various compounds was also found. On the basis of the analytical results as well as the pathological findings on Baltic seals, the group of DDE and PCB methyl sulfones is tentatively suggested to be more important in explaining the disease complex than coplanar structures including dioxins.

Adrenal Gland Diseases↗
PubMed1994

Endometrial thickness as measured by transvaginal sonography: interobserver variation.

Transvaginal sonography of the uterus has become an important tool for diagnosing endometrial pathology in women with postmenopausal bleeding. One parameter that has been claimed to be important for curly detection of endometrial pathology in this group of women is the endometrial thickness. The purpose of this study was to evaluate the reproducibility of measurements of endometrial thickness as performed by five inexperienced doctors and one doctor experienced in the transvaginal sonography technique. The endometrial thickness as measured by the experienced doctor was regarded as the 'true measurement', and the mean discrepancy from this true measurement was 1.5 mm for the inexperienced doctors. No endometrial pathology was found at the histopathological examination after dilatation and curettage (D & C) when the endometrial thickness was measured as <or= 4 mm by both the inexperienced and the experienced doctors. However, there were considerable differences between the results obtained by the five inexperienced doctors. If this method is to be used for identifying those women who will not have a D & C performed, based on the findings of a thin endometrium (<or= 4 mm), training is needed in order to minimize the error. We believe that this will make measurement more accurate and it may then be used to exclude endometrial abnormality in women with postmenopausal bleeding.

Journal Article↗
PubMed1994

Stereotactic radiosurgery for tectal low-grade gliomas.

We report 7 cases with low-grade gliomas in the tectal region of the midbrain. This series started in 1979 and all tumors were treated by radiosurgery using the Leksell Gamma Knife. All cases were treated by using a single isocenter with the 14 mm collimator. Doses administered ranged from 14 to 35 Gy delivered to the 50-70% isodose line. All tumours but one responded to the treatment and disappeared or ceased growing. In the first two treated cases, the dose was chosen by the early experience from the AVM's, with 30 and 35 Gy as the peripheral dose. These cases developed severe radio-induced oedema with aggravating symptoms and permanent deficits. We conclude that radiosurgery is effective in the treatment of deeply located low-grade gliomas. Cases accepted for treatment should be carefully selected and the peripheral dose should not exceed 14Gy to avoid uncontrolled radio-induced changes.

Adolescent↗
PubMed1994

Multiple intracranial arteriovenous malformations: a case report.

Multiple intracranial arteriovenous malformations are rare. There are a few cases in the literature with up to three malformations in one patient. A child with seven separate cerebral malformations is now described. There was no history of haemorrhage, but only of febrile seizures. The malformations were discovered at CT and verified at angiography. Six were selected for stereotaxic irradiation with the multi-cobalt unit. The seventh was considered too big for irradiation and suitable for surgery.

Cerebral Angiography↗
PubMed1994

125I-labelling of an internally 75Se-labelled monoclonal antibody--biodistribution in tumour-bearing nude mice.

A monoclonal antibody, C215, was first internally labelled with 75Se-methionine and then labelled with 125I. The biodistribution of the dual-labelled [125I][75Se]C215 was studied in tumour-bearing nude mice killed 3 days after injection. The biodistribution of the dual-labelled [125I][75Se]C215 was compared with the biodistribution of single-labelled [131I]C215 and [75Se]C215. Iodine-labelled antibodies seem to be damaged during iodination, affecting the disappearance rate and tumour uptake. There were no signs of dehalogenation of circulating antibodies or antibodies taken up in the tumour.

Adenocarcinoma↗
PubMed1994

The protective effect of nimodipine, a calcium antagonist, and its influence on soman clearance in the anaesthetized rabbit.

The effect of pretreatment with a vasoactive compound, nimodipine, on soman intoxication in peripheral organs of rabbits was studied by measuring changes in the cholinesterase and acetylcholinesterase activity and by measuring clearance of soman in blood using gas chromatography/high resolution mass spectrometry. In animals receiving soman only, initial blood concentrations were approximately 100 ng mL-1 and were still detectable after 5 min. The clearance rate of soman in blood markedly increased following nimodipine pretreatment such that soman was below the detection limit (0.002-0.003 ng mL-1) in all samples. Soman injection caused a significant inhibition of the acetylcholinesterase activity in serum, and in brain. In rabbits pretreated with nimodipine, no significant inhibition of acetylcholinesterase activity occurred after soman injection. In view of the effects of nimodipine on soman clearance and on the acetylcholinesterase and cholinesterase inhibition during soman intoxication, we suggest that nimodipine has profound circulatory effects, which during soman intoxication, increase the vascular perfusion through the body and thereby increase the detoxifying capacity.

Acetylcholinesterase↗
PubMed1994

Simultaneous measurements of cerebral circulation with electromagnetic flowmetry and Doppler ultrasound velocity in the newborn pig.

Cerebral blood flow measurement has been an important investigative tool in newborns at risk for perinatal brain damage. The validity of Doppler cerebral blood flow velocity measurements depends on a constant vessel diameter. We have validated Doppler against the electromagnetic flowmeter (EM) using a modified common carotid artery model in the 1-d-old piglet. Two sets of continuous and simultaneous recordings were performed: 1) the Doppler and EM probe on the same common carotid artery (extracerebral branches were ligated), and 2) the EM probe on the common carotid artery and the Doppler probe recording from an intracerebral artery through an artificial fontanel. Arterial partial pressure of carbon dioxide (PaCO2) was manipulated (2.8-7.4 kPa), as was arterial blood pressure (3.7-9.3 kPa). Simultaneous EM flow and estimated Doppler flow were compared. Ninety-three recordings were obtained with both transducers on the modified carotid artery, and 49 were obtained with the Doppler insonicating an intracerebral artery. A multiple regression model was used for statistical analysis. The correlation between EM and both sets of Doppler measurements for individual animals was > 0.95 and was unaffected by changes in arterial blood pressure or PaCO2. Thus, the common carotid and the intracerebral artery investigated did not change their diameter significantly in response to PaCO2 or arterial blood pressure. The relationships between EM and Doppler in the individual animal were all linear but revealed great variability in the slopes due to the unknown vessel diameter and angle of insonication.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Comparative study of transvaginal sonography and hysteroscopy for the detection of pathologic endometrial lesions in women with postmenopausal bleeding.

Dilatation and curettage is used as the "gold standard" for diagnosing pathologic endometrial lesions in women with postmenopausal bleeding. In this group of women, about 10% have an endometrial cancer and an additional 20% have some other endometrial abnormality. However, some abnormalities, such as endometrial polyps and submucous fibroids, are difficult to diagnose by dilatation and curettage. In such cases, combining transvaginal sonography with hysteroscopy may be of value. This study compared the use of transvaginal sonography and hysteroscopy for evaluation of the uterine cavity in women with postmenopausal bleeding. The study included 51 women, 39 of whom had an abnormally thick ( > 4 mm) endometrium as measured by transvaginal sonography, and 35 of 39 had an abnormal appearance at hysteroscopy. The sensitivity and specificity for the measurement of endometrial thickness using transvaginal sonography to diagnose an endometrial abnormality were 100% and 75%, respectively. The corresponding figures for hysteroscopy were 97% and 88%. In all women with an endometrial thickness of 8 mm as measured by transvaginal sonography, hysteroscopy is identified as an abnormality. The study indicates that transvaginal sonography reveals an endometrial thickness of > or = 8 mm and the histopathologic diagnosis after dilatation and curettage is atrophic endometrial polyp or submucous myoma.

Aged↗
PubMed1993

Gamma knife surgery of cerebral arteriovenous malformations: serial MR imaging studies after radiosurgery.

PURPOSE: To investigate the temporal sequence of post radiosurgery magnetic resonance imaging changes in cerebral arteriovenous malformations. METHODS AND MATERIALS: Eighteen patients were regularly followed up after gamma knife surgery. The follow-up intervals ranged from one day to 44 months. High signal lesion in or around arteriovenous malformations on T2-weighted magnetic resonance images corresponding to the treatment volume and developing after radiosurgery were defined as the adverse reaction of the irradiation. This high signal and the regression of arteriovenous malformations nidus after radiosurgery were evaluated. RESULTS: Adverse reaction of irradiation was observed in nine cases. Seven of them were symptomatic. The reactions presented as focal high signal in three cases and focal high signal with extension along the neural tracts in six cases. The reactions were seen either immediately after treatment (one case), between 3 and 14 months (seven cases), and 40 months after treatment (one case). The regression of the adverse reaction was observed to start 5 +/- 3 months after its appearance. Regression of the arteriovenous malformations' nidus was found in 16 cases. In two cases the AVMs became invisible on magnetic resonance images but the angiogram still demonstrated abnormal shunts. In another one case with angiogram showing total obliteration, the nidus was erroneously interpreted as incomplete obliteration on magnetic resonance images. CONCLUSION: It is concluded that magnetic resonance imaging is a sensitive in vivo method for detecting cerebral radiation injury. Magnetic resonance imaging offers a method for evaluating the regression of arteriovenous malformations' nidus, but the diagnosis of complete obliteration of the nidus after radiosurgery still relies on the angiogram.

Adolescent↗
PubMed1993

Endovaginal scanning of the endometrium compared to cytology and histology in women with postmenopausal bleeding.

Endovaginal scanning (EVS) of the endometrium has recently been proposed as a method for the investigation of the endometrial mucosa. In this study, the specificity and sensitivity of EVS have been compared with endometrial cytology and D&C to discriminate between a normal and pathological endometrium. The study included 105 women who underwent preoperative endovaginal ultrasound investigation, endometrial cytology, and D&C because of postmenopausal bleeding. A specificity of 81% and a sensitivity of 97% in diagnosing morphological alterations by means of endovaginal ultrasound was found. The corresponding figures for cytological evaluation were 81 and 58%, respectively. We conclude that endovaginal ultrasound is a valuable diagnostic instrument for detecting pathological conditions in the uterine mucosa and as sensitive as endometrial cytology or D&C.

Aged↗
PubMed1993

Even the smallest remnant of an AVM constitutes a risk of further bleeding. Case report.

A case with an ill-defined arteriovenous malformation in the parieto-occipital region is presented. Open surgery was unsuccessful in removing the AVM totally, and treatment with gamma knife radiosurgery was then attempted. At 14 months after this treatment the AVM was believed to be obliterated. The patient had a new intracranial haemorrhage 59 months after radiosurgery. Renewed angiography showed an obvious AVM outside the previously irradiated area. Retrospective analysis of the angiogram at 14 months after radiosurgery revealed early filling of a draining vein as a sign of residual AVM at this time. Renewed radiosurgical treatment was performed. It is believed that an ill-defined margin, laminar flow, and effects of previous surgery might add to difficulties in a proper visualisation and delineation of an AVM. Further, a small remaining shunt may be overlooked if the angiogram is not carefully analysed or if the angiogram is of inferior quality. It should be stressed that partial or almost total obliteration of an AVM is no protection against rebleeding.

Cerebral Angiography↗
PubMed1993

Replacing diagnostic curettage by vaginal ultrasound.

Dilatation and curettage has for many years been the method of choice for diagnosing endometrial cancer in postmenopausal women. However, less than 10% of women with postmenopausal bleeding have an endometrial cancer. Vaginal sonography for measuring endometrial thickness, has in several studies proved to be a sensitive diagnostic method for diagnosing endometrial pathology. Our studies as well as others have shown that an endometrial thickness of 4 mm or less (including both endometrial layers) indicates a very low risk for endometrial carcinoma as well as any other major endometrial pathology in women with postmenopausal bleeding. Since vaginal sonography is such a simple and a non-invasive diagnostic method, it thus seems reasonable that vaginal sonographic assessment of the endometrium should be the primary method for excluding any endometrial abnormality in a woman with postmenopausal bleeding.

Aged↗
PubMed1993

Therapy with 125I-labelled internalized and non-internalized monoclonal antibodies in nude mice with human colon carcinoma xenografts.

The therapeutic effects of 125I-labelled (18-97 MBq) monoclonal antibodies (MAb) C-242, C-215 and S-S.1 were studied in nude mice with human colorectal adenocarcinoma tumours. The antibodies were administered 2 or 10-16 days after implantation of the tumour cells. The monoclonal antibody C-242 was internalized into the tumour cells, C-215 was internalized to a lower degree while S-S.1 (unspecific MAb) was not internalized at all. No enhanced therapeutic effect of 125I-C-242 was observed, as a result of Auger electrons, compared with 125I-C-215 and 125I-S-S.1.

Adenocarcinoma↗
PubMed1993

Gamma Knife surgery for cerebral metastases. Implications for survival based on 16 years experience.

Our experience with radiosurgery of brain metastases is based on 160 patients with 235 tumors treated over a 16-year period. In this material, 94% growth control was achieved. Radiosurgery appears to be an effective, low-morbidity substitute for surgical resection followed by whole brain radiotherapy and even indicated for multiple metastases and distant new tumors. More patients receive an effective treatment with less neurologically related deaths.

Brain↗
PubMed1993

Radiosurgery for venous angiomas.

Radiosurgical treatment with the gamma knife for venous angiomas was used as an alternative to microsurgical removal in order to avoid abrupt cessation of venous drainage, which may be shared by the venous angioma and important parts of the brain. Thirteen cases of venous angioma were treated between 1977 and 1991. In two cases cavernous angiomas were also present and in one case a distant arteriovenous malformation (AVM) was also found. In two cases the angioma shared the venous drainage with an adjoining AVM; this is the first description of such pathology. For venous angiomas irradiation was prescribed to cover at least the convergence of the medullary veins. For AVM's close to a venous angioma the treatment was exclusively prescribed to the AVM nidus. After treatment, complete obliteration of the venous angioma was observed in one case, partial obliteration was observed in three cases, and five venous angiomas were unaffected by the treatment. Undue effects of radiation occurred in four cases: one focal edema and three radionecroses. Extirpation of the radionecrotic tissue 6 months after radiosurgery was necessary in one case. In the other three cases, the venous angioma was observed to be completely or partially obliterated, or unaffected by the treatment (one case each). In two cases of combined AVM and venous angioma, complete obliteration of the treatment AVM nidus was obtained. It is concluded that radiosurgery for venous angioma, although conceptually attractive, still does not fulfill the rigid criteria of minimal risk which must be set for the treatment of a lesion with a benign natural history.

Adult↗