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Biomedical subjects

T Möller

Publications and source records attributed to T Möller.

At least 19 recordsLinked to original sources
PubMed2000

Increased cancer risk in offspring of women with colorectal carcinoma: a Swedish register-based cohort study.

BACKGROUND: Colorectal carcinoma is one of the most common malignancies in the Western population, and a considerable proportion of colorectal carcinomas are estimated to have a familial background. METHODS: Individuals whose mothers were diagnosed with colon carcinoma or rectal carcinoma from 1958 to 1993, a total of 1. 48 million person-years, constituted the cohort of this Swedish population-based register study. The children were born during the period 1941-1993, and the cancer incidence was observed during the period 1961-1993, with the expected national Swedish incidence used as a reference. RESULTS: A significantly increased risk of colon carcinoma, rectal carcinoma, and non-Hodgkin lymphoma was observed in the cohort. The cancer risk was more pronounced in children whose mothers were age < 50 years at the time of diagnosis or had developed metachronous colorectal carcinoma. Whereas colon carcinoma in the proband implied an increased risk for both colon tumors and rectal tumors, the offspring of women who were diagnosed with rectal carcinoma were at increased risk of developing rectal carcinoma, but no significantly altered risk of colon carcinoma was observed. In the cohort, the cumulative risk for colorectal carcinoma before age 50 years was increased about 3.0 times compared with the general population. CONCLUSIONS: This report shows a significant familial aggregation of colorectal carcinoma, demonstrates possible differences in hereditary pattern between colon carcinoma and rectal carcinoma, and confirms that younger age at the time of diagnosis or the occurrence of metachronous tumors indicate familial carcinoma.

Cohort Studies↗
PubMed2000

Activation of mouse microglial cells affects P2 receptor signaling.

Microglial cells are the immunocompetent cells of the CNS, which are known to exist in several activation states. Here we investigated the impact of microglial activation on the P2 receptor-mediated intracellular calcium ([Ca(2+)](i)) signaling by means of fluo-3 based Ca(2+)-imaging. Cultured mouse microglial cells were treated with either astrocyte-conditioned medium to induce a ramified morphology or LPS to shift the cells toward the fully activated stage. The extracellular application of ATP (100 microM) induced a [Ca(2+)](i) elevation in 85% of both untreated and ramified microglial cells, whereas only 50% of the LPS-activated cells responded to the stimulus. To characterise the pharmacological profile of microglial P2 receptors we investigated the effects of various P2 agonists on [Ca(2+)](i) in cultured microglial cells. Untreated and ramified microglial cells demonstrated a very similar sensitivity to the different P2 agonists. In contrast, in LPS-activated microglia, a sharp decrease of responses to P2 agonist stimulation was seen. This indicates that microglial activation influences the capability of microglial cells to generate [Ca(2+)](i) signals upon P2 receptor activation.

Adenosine Triphosphate↗
PubMed2000

Rapid ischemic cell death in immature oligodendrocytes: a fatal glutamate release feedback loop.

Ischemic injury of immature oligodendrocytes is a major component of the brain injury associated with cerebral palsy, the most common human birth disorder. We now report that cultured immature oligodendrocytes [O4(+)/galactoceramide (GC)(-)] are exquisitely sensitive to ischemic injury (80% of cells were dead after 25.5 min of oxygen and glucose withdrawal). This rapid ischemic cell death was mediated by Ca(2+) influx via non-NMDA glutamate receptors. The receptors were gated by the release of glutamate from the immature oligodendrocytes themselves via reverse glutamate transport and included a significant element of autologous feedback of glutamate from cells onto their own receptors. High (> or = 100 microM) extracellular glutamate was protective against ischemic injury as a result of non-NMDA glutamate receptor desensitization. Other potential pathways of Ca(2+) influx, such as voltage-gated Ca(2+) channels, NMDA receptors, or the Na(+)-Ca(2+) exchanger, did not significantly contribute to ischemic Ca(2+) influx or cell injury. Release of Ca(2+) from intracellular stores was also not an important factor. In agreement with previous studies, more mature oligodendrocytes (O4(-)/GC(+)) were found to be less sensitive to ischemic injury than were the immature cells studied here.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed2000

Accrual rate-limiting factors in a Swedish randomised ductal carcinoma in situ (DCIS) trial - a demographic study.

In the last two decades the introduction of mammographic screening in the Western world has increased the number of diagnosed ductal carcinomas in situ (DCIS) considerably. In situ carcinoma of the breast is considered a heterogeneous disease, the natural history of which is not well known. Thus, appropriate treatment needs to be established. For this reason, a randomised trial studying the effect of breast conserving operation with or without postoperative radiotherapy was instituted in Southern Sweden in 1987. The aim of the present study was to assess patient accrual, identify limiting factors, and evaluate possible ways to influence these factors in order to increase patient accrual. Between 1987 and 1992, 331 patients had been registered with DCIS in the Regional Tumour Registry, 96 of which had been randomised. All 331 were subjected to chart review studying clinical data, mammography reports, cytology and pathology reports to identify inclusion and exclusion criteria according to the design of the trial. It was found that 5% (18/331) had an incorrect diagnosis of DCIS. According to the trial protocol 52% were not eligible (162/313). Fifty-eight per cent (n=88) of the 151 eligible patients had been correctly randomised. The most common reason for exclusion was lesion size. In 21% (66/313) the lesion was 'too large'. Several other limiting factors were identified such as in cytological and pathological definitions and reports, lack of information/awareness in certain physicians, patient reluctance to participate, which in turn may be influenced by the previous factor. With increased information to participating hospitals and considering the above given facts it should be possible to increase accrual from the 28% noted in the present consecutive demographic study to at least one-third of the diagnosed cases of DCIS.

Breast Neoplasms↗
PubMed2000

Thrombin-induced activation of cultured rodent microglia.

Microglia are the resident immune cells of the CNS. Upon brain damage, these cells are rapidly activated and function as tissue macrophages. The first steps in this activation still remain unclear, but it is widely believed that substances released from damaged brain tissue trigger this process. In this article, we describe the effects of the blood coagulation factor thrombin on cultured rodent microglial cells. Thrombin induced a transient Ca(2+) increase in microglial cells, which persisted in Ca(2+)-free media. It was blocked by thapsigargin, indicating that thrombin caused a Ca(2+) release from internal stores. Preincubation with pertussis toxin did not alter the thrombin-induced [Ca(2+)](i) signal, whereas it was blocked by hirudin, a blocker of thrombin's proteolytic activity. Incubation with thrombin led to the production of nitric oxide and the release of the cytokines tumor necrosis factor-alpha, interleukin-6, interleukin-12, the chemokine KC, and the soluble tumor necrosis factor-alpha receptor II and had a significant proliferative effect. Our findings indicate that thrombin, a molecule that enters the brain at sites of injury, rapidly triggered microglial activation.

Adenosine Triphosphate↗
PubMed2000

["Non-solvent shock agglomeration technology" as a new alternative method for work on ibuprofen. 4. Production and evaluation of quick release forms].

During compaction of shock-agglomerated S(+)ibuprofen it was of interest if and how far the sometimes strongly differing quality or the origin of the source material has effects on the tabletting properties and on tablet quality. Moreover, conventional and shock agglomerated substances are compared with regard to the parameters mentioned. The technology of "non-solvent shock agglomeration" results in substances suitable for direct tabletting. Additionally, the resulting comprimates have characteristics which can be clearly traced back to the special quality of the ibuprofen-shock agglomerates. By using different agents in the process of substance preparation specific galenic properties can be achieved.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

["Non-solvent shock agglomeration"--technology of a new alternative method for sustained release of ibuprofen. 5. Production and evaluation of retard formulations].

Conventional and prepared racemic and optically pure substances were assessed with regard to their suitability to be processed into retarded formulations by direct tabletting. In this respect conventional ibuprofen and specially granulated substances usually show only insufficient properties. Fluid bed granulated S(+)ibuprofen, however, can be suitably transformed into slow release forms by using traditional agents (above all cellulose ether); the low bulk and tapped volume of these granulates, however, is a limiting factor. Shock agglomerated ibuprofen (in particular racemic substance) offers all preconditions of dissolution in acid environment correspondingly prepared substances can cause significant release retardation in artificial intestinal juice. Moreover acceptable tablet qualities (e.g. hardness) can be guaranteed.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

["Non-solvent shock agglomeration"--the technology of a new alternative method for determination of ibuprofen. 6. Stability of s(+)-ibuprofen].

Due to its low melting range approx. 53 degrees C optically pure ibuprofen can be regarded as problematic in a pharmaceutic-technological sense. With regard to the non-solvent shock agglomeration method this means that the process and product temperatures must strictly be kept in the range of 10 K above the melting point of the substance. Higher temperatures can induce degradation of S(+)ibuprofen. During storage under stress conditions (31 degrees C for a period of 18 months) ibuprofen shows extreme stability independent of its optical activity. Racemic ibuprofen is inert to the influence of light; in individual cases optically pure substance containing an increased level of impurities can show slight degradation tendencies. The thermal and photo stability of ibuprofen is independent of the preparation technology. For comparison, conventional, fluid bed granulated, briquetted and from organic solvents especially recrystallised and optically active substances were investigated besides the shock agglomerated substances.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

Lysophosphatidic acid-induced calcium signals in cultured rat oligodendrocytes.

Oligodendrocytes are the myelin forming glial cells of the CNS and are known to express receptors linked to ion channels and intracellular second messenger cascades. In this paper, we describe the intracellular calcium responses of cells from the oligodendrocyte lineage to application of lysophosphatidic acid (LPA), a naturally occurring, growth factor-like phospholipid. Oligodendrocyte precursors did not respond to application of LPA (1 microM). In mature oligodendrocytes, however, LPA (1 microM) induced an increase in the intracellular calcium concentration ([Ca2+]i). In the majority of cells this increase was followed by a persistent plateau phase. The LPA-induced [Ca2+]i signal vanished in Ca2+-free medium, implying that it arose due to a Ca2+ influx across the plasma membrane. Preincubation of the cells with Pertussis-toxin prevented the generation of LPA-induced [Ca2+]i signals. We conclude that cultured rat oligodendrocytes express functional LPA receptors, which mediate a transmembrane Ca2+ influx via a Pertussis-toxin-sensitive G-protein.

Animals↗
PubMed1999

Incidence of malignant tumours in relatives of BRCA1 and BRCA2 germline mutation carriers.

We investigated cancer incidence between 1958 and 1995 in 1873 individuals belonging to 29 consecutively identified BRCA1 and 20 BRCA2 associated families from Southern Sweden using data from parish and local tax authorities, as well as the Swedish Cancer Registry, Cause of Death Registry and Census Registry. 150 malignant tumours were analysed from 1145 relatives in the BRCA1 families and 87 tumours were analysed from 728 relatives in the BRCA2 families. After excluding index cases which led to the mutation analysis, the incidence for all malignant tumours was significantly increased for both BRCA1- standardised morbidity rate, SMR, 1.98, 95% confidence interval (CI) 1.59-2.45; P < 0.0001 and BRCA2- (SMR 1.79, 95% CI 1.35-2.31; P < 0.0001) associated family members. For women in BRCA1-associated families, the incidence of breast cancer (SMR 3.76, 95% CI 2.29-5.80, P < 0.0001), ovarian cancer (SMR 15.49, 95% CI 9.46-23.92, P < 0.0001), stomach cancer (SMR 5.86, 95% CI 1.60-15.01, P = 0.005) were significantly increased. Amongst men only invasive squamous cell cancer of the skin was significantly increased (SMR 6.02, 95% CI 1.96-14.05, P = 0.002). In BRCA2 associated families, female breast cancer (SMR 3.03, 95% CI 1.61-5.18, P = 0.0005) was increased after exclusion of index cases. If these were included, ovarian cancer (SMR 5.16, 95% CI 1.89-11.24, P = 0.001), invasive cervical cancer (SMR 4.21, 95% CI 1.15-10.79, P = 0.016), male breast cancer (SMR 290.52, 95% CI 125.42-572.43, P < 0.0001), and prostate cancer (SMR 2.21, 95% CI 0.89-4.56, P = 0.042) were significantly increased. The increased risk for ovarian cancer in BRCA2 related families were limited to the cases leading to mutation analysis. Our data suggest that apart from breast and ovarian cancer, the incidence of other cancer types do not appear to be greatly increased in BRCA1- and BRCA2-associated families and does not warrant specific clinical follow-up in carriers.

Adult↗
PubMed1999

Microdomains for neuron-glia interaction: parallel fiber signaling to Bergmann glial cells.

Astrocytes are considered a reticulate network of cells, through which calcium signals can spread easily. In Bergmann glia, astrocytic cells of the cerebellum, we identified subcellular compartments termed 'glial microdomains'. These elements have a complex surface consisting of thin membrane sheets, contain few mitochondria and wrap around synapses. To test for neuronal interaction with these structures, we electrically stimulated parallel fibers. This stimulation increased intracellular calcium concentration ([Ca2+]i) in small compartments within Bergmann glial cell processes similar in size to glial microdomains. Thus, a Bergmann glial cell may consist of hundreds of independent compartments capable of autonomous interactions with the particular group of synapses that they ensheath.

Animals↗
PubMed1998

Long-term activation of capacitative Ca2+ entry in mouse microglial cells.

The cytoplasmic free calcium concentration ([Ca2+]i) was measured in cultured microglial cells with the Ca2+-sensitive fluorescent dye Fura-2 using a digital imaging system. Stimulation of P2 purinergic receptors by ATP or UTP always evoked a [Ca2+]i elevation. The ATP-induced Ca2+ response involved both Ca2+ influx through ionotropic receptors and Ca2+ release from intracellular pools, whereas UTP selectively stimulated intracellular Ca2+ release. When intracellular Ca2+ release was stimulated in the absence of extracellular Ca2+, the readmission of extracellular Ca2+ caused a large rebound [Ca2+]i increase. Following this rebound, [Ca2+]i did not return to the initial resting level, but remained for long periods of time (up to 20 min), at a new, higher steady-state level. Both the amplitude of the rebound Ca2+ transient and the new plateau level strongly correlated with the degree of intracellular Ca2+ depletion, indicating the activation of a store-operated Ca2+ entry pathway. The elevated steady-state [Ca2+]i level was associated with a significant increase in the plasma membrane permeability to Ca2+, as changes in extracellular Ca2+ were reflected in almost immediate changes of [Ca2+]i. Similarly, blocking plasma-lemmal Ca2+ channels with the non-specific agonist La3+ (50 microM) caused a decrease in [Ca2+]i, despite the continuous presence of Ca2+ ions in the extracellular medium. After the establishment of the new, elevated steady-state [Ca2+]i level, stimulation of P2U metabotropic purinoreceptors did not induce a [Ca2+]i response. In addition, application of either thapsigargin (1 microM) or carbonyl cyanide chlorophenyl hydrazone (10 microM) failed to affect [Ca2+]i. We conclude that the maximal depletion of intracellular Ca2+ stores in mouse brain microglia determines the long-term activation of a plasma membrane Ca2+ entry pathway. This activation appears to be associated with a significant decrease in the capability of the intracellular Ca2+ stores to take up cytosolic Ca2+ once they have been maximally depleted.

Adenosine Triphosphate↗
PubMed1998

Teaching oncology and cancer care to general practice trainees in Sweden: a two-year prospective, randomized study.

OBJECTIVE: To improve general practice (GP) trainees' knowledge of and attitudes towards oncology and their management of cancer patients. METHOD: A prospective study of 33 GP trainees who, after a first assessment, were randomized either to attend a two-year cancer course (n = 17) or to a control group (n = 16). Both groups were tested at the beginning (pretest) and end (post-test) of the two years. The maximum possible score was 76. All tests were corrected blindly by an oncologist and a general practitioner. RESULTS: The intervention group showed significant post-test-pretest improvements in the domains "knowledge" (mean difference 2.6, 95% CI 1.3-3.8) and "attitudes" (mean difference 2.9, 95% CI 0.8-5.0), but not in "patient management" (mean difference 0.3, 95% CI -0.6-1.2). There was no significant change in the test scores of the controls. The total mean (post-test-pretest) differences were 8.3 (95% CI 4.9-11.6 for the intervention group and -1.4 (95% CI -4.1-1.3) for the controls. CONCLUSION: A low-intensity two-year cancer course improved the knowledge and attitudes of GP trainees. Patient management, however, was not improved and may be more suited for hospital training. The current five-year specific training in general practice in Sweden seemed to be of limited value in the field of oncology. Thus, there is a need for further development of educational tools for cancer training of GP trainees, at least in Sweden.

Clinical Competence↗
PubMed1998

Dye coupling between spinal cord oligodendrocytes: differences in coupling efficiency between gray and white matter.

Oligodendrocytes express two gap junction proteins, connexin32 (Cx32) and Cx45. To test for functional coupling between oligodendrocytes, cells were filled with the (Cx32-permeable) dyes Lucifer Yellow (LY) and Neurobiotin. Cells in slices from rat spinal cord were dialyzed via the patch pipette containing the dye while recording with the patch-clamp technique. The dye-labeled cells were identified as oligodendrocytes by their characteristic pattern of membrane currents and by morphology. In gray matter, 18% of the injected cells (N = 94) were coupled to more than three adjacent cells (slices from postnatal day 1 to 19). In contrast, in white matter, the dye was restricted to the injected cell (N = 63 for Lucifer Yellow injection only; N = 11 for LY and Neurobiotin) indicating a lack of functional coupling. Immunolabeling of Cx32 in mature oligodendrocytes of white matter revealed that the gap junction protein is localized on the cell bodies and abaxonal processes which occupy non-overlapping territories. In immature white matter and gray matter, Cx32 is mostly concentrated in the somatic region of the cells. In addition to Cx32, we have obtained immunocytochemical data that oligodendrocytes can express Cx45 with a labeling pattern different from the Cx32 expression. Two alternative interpretations of the coupling data are discussed: 1) that the presence of Cx32 in mature white matter oligodendrocytes does not serve for communication between cells, but rather for communication within oligodendrocytes in the sense of autocellular coupling, or 2) that the glial syncytium is furnished with a high degree of functional rectification at the oligodendrocytic side.

Animals↗
PubMed1998

Blood transfusion at delivery and risk of subsequent malignant lymphoma in the mother.

BACKGROUND AND OBJECTIVES: Blood transfusion has been shown to be a risk factor for non-Hodgkin's lymphoma (NHL). MATERIALS AND METHODS: In a cohort of 77,928 women with bleeding complications at delivery in the period of 1973-1986, subsequent NHL cases were identified and the number was compared with the number expected from national incidence rates. In a case-control study the proportion of transfused NHL cases was compared with the proportion of transfused controls. RESULTS: The observed number of NHL in the cohort was 18 versus 22.0 expected. Information on transfusion was obtained for 15 of the NHL cases and none (0%) was transfused versus 32 out of 136 controls (23%). CONCLUSIONS: Blood transfusion at delivery is not a risk factor for NHL. The immune tolerance induced by pregnancy may reduce the risk of NHL associated with the transfusion of allogeneic blood cells.

Adult↗
PubMed1997

Microglial phagocytosis is modulated by pro- and anti-inflammatory cytokines.

Activation of microglial cells in neurological diseases involves proliferation and the induction of phagocytic and cytotoxic properties. We studied the effects of four different cytokines on microglial phagocytosis of latex beads to gain further insights into the signals modulating different aspects of microglial activity. Granulocyte/macrophage colony stimulating factor and tumor necrosis factor-alpha enhanced microglial phagocytic activity as measured by flow cytometry. A phagocytosis inhibiting effect was observed after preincubation with transforming growth factor-beta1 and interleukin-4. In conclusion, the activating and deactivating cytokines differentially regulate microglial phagocytic activity in vitro and might also play an important role in vivo in modulating microglial activation to keep the balance between the protective, defensive and destructive, chronic inflammatory properties of microglia.

Animals↗