The diabetogenic action of alloxan on pancreatic beta-cells is thought to be mediated by hydroxyl... more The diabetogenic action of alloxan on pancreatic beta-cells is thought to be mediated by hydroxyl radicals. The initial attack of the radicals is probably at the plasma membrane level. Diethyldithiocarbamate (DDTC) and its dimer disulfiram (Antabuse) have recently been shown to protect against damage by free radical generating agents. The ability of DDTC and disulfiram to inhibit alloxan-induced dye accumulation of isolated ob/ob mice islet beta-cells was therefore studied. Evans blue was used as an indicator of plasma membrane permeability. DDTC (100 microM 1 mM) but not disulfiram (100 microM 1 mM) inhibited alloxan-induced dye uptake of beta-cells. The effect of DDTC on oxygen consumption in a mixture of reduced glutathione (GSH), alloxan and FeSO4 was studied with a Clark-type oxygen electrode. DDTC (20, 100 microM) had no effect on the oxygen consumption of this mixture. It is suggested that the DDTC inhibition of alloxan-induced dye uptake of isolated beta-cells takes place at a step beyond the generation of free radicals.
The ultrastructure of beta-cell granules was examined after fixation of isolated mouse islets in ... more The ultrastructure of beta-cell granules was examined after fixation of isolated mouse islets in fixatives of various compositions. Islets fixed in glutaraldehyde with or without post-fixing in osmium tetroxide, or in osmium tetroxide alone, exhibited the classical picture of electron-dense core surrounded by a lucid halo. After fixation in potassium permanganate, with or without post-fixing in osmium, the secretory vesicle was often completely filled with a fairly homogeneous material; the vesicle membrane was distinct in outline. When glutaraldehyde-fixed beta-cells were stained according to Rambourg to visualize reducing groups, possibly carbohydrates, two distinct classes of secretory granules were observed, one darkly stained and one faintly, without any noticeable precipitation of silver; the perigranular halo remained unstained in both types of granules. The perigranular halo of aldehyde and osmium fixed beta-granules also remained unstained in cells exposed to the osmiophilic amine, 5,6-dihydroxytryptamine.
The re-aggregation of dispersed islet cells from non-inbred ob/ob-mice was studied by light and e... more The re-aggregation of dispersed islet cells from non-inbred ob/ob-mice was studied by light and electron microscopy. After 3 days of culture, spontaneously formed aggregates with more than 95% beta-cells were up to 0.5 mm in diameter and exhibited a high degree of viability on dye exclusion tests. In comparison with cultures at 1 or 3 mM D-glucose, or 1 mM D-glucose in combination with 19 mM 3-0-methyl-D-glucose, aggregates formed in 20 mM D-glucose were more closely packed, had a smoother circumference with elongated peripheral beta-cells, and exhibited well developed micro-villi in localized intercellular widenings. A stereological analysis of electron micrographs showed that beta-cells aggregated at 20 mM D-glucose exhibited the same individual profile area but a significantly lower form factor, and a significant reduction in granule volume density as compared with aggregates at 3 mM D-glucose. It is concluded that D-glucose has morphogenetic effects on both the cellular and the ...
Potassium and chloride transport were measured in P-cell-rich islets from oblob-mice using Wand 8... more Potassium and chloride transport were measured in P-cell-rich islets from oblob-mice using Wand 86Rb+ (K+-analogue). Reduction of the osmolarity from the normal 317 mosm 1-I to 180 mosm 1-1 reduced the apparent content of K+ and C1-. Hypo-osmolarity had no effect on the ouabain-sensitive portion of the Rb+ influx (Na+/K+ pump), but reduced the ouabain-resistant portion of the influx. Hypo-osmolarity also strongly increased the Rb+ efflux rate. Both tetracaine (0.5 mM) and glibenclamide (20 p~) , which increase the osmotic resistance of pancreatic P cells, significantly potentiated the reduction in apparent K+ content induced by hypo-osmolarity. This study suggests that the volume regulation in pancreatic 1 cells is partly due to K+ and C1-flux and that glibenclamide and tetracaine increase the osmotic resistance of the P cells by affecting such ion transport.
Dispersed islet cells from noninbred ob/ob mice were cultured for 3 days with 3 or 20 mM D-glucos... more Dispersed islet cells from noninbred ob/ob mice were cultured for 3 days with 3 or 20 mM D-glucose and silver stained according to Rambourg et al. Two tinctorial subsets of dark and light intracellular granules were analyzed by morphometry at the ultrastructural level. The two types of granules were similar in size and shape. However, with 3 mM glucose the dark granule cores were surrounded by larger vesicles than the light granules. With 20 mM glucose, both types of granule vesicles and cores became smaller and dark-granule cores became more rounded, compared with cultures with 3 mM glucose. The higher glucose concentration also induced a marked decrease in the number (-84%) and volume density (-90%) of dark granules. In contrast, the number of light granules increased (+60%) with maintenance of their volume density. We suggest that the dark Rambourgpositive and the light Rambourg-negative p-cell granules are functionally distinct subsets. The dark granules are probably engaged in insulin discharge. We discuss the unclear role of the light granules with a view to previously postulated heterogeneities of the insulin granule pool and their significance for exocytosis and intracellular hormone degradation. Diabetes 37:194-99,1988 F unctional as well as morphological studies (1-4) have indicated that the secretory granules in the pancreatic p-cells represent a heterogenous population of organelles. In standard electron micrographs, the granules show a continuum in electron density from grey to dark. However, after silver staining according to Rambourg et al. (5), two fairly distinct pools of granules were observed, one very light and one black (6). The mean-From the
According to the National Board of Health and Welfare, SOSFS 2005:12, it is required that the car... more According to the National Board of Health and Welfare, SOSFS 2005:12, it is required that the caregiver adheres to his work through following stated objectives. Formulating goals in health care requires careful consideration. Goals must be measurable and include many different aspects of the project. Each improvement project is unique and should be directly related to the resources allocated to the project. A major problem for continuous monitoring is to select parameters that provide sufficient information and are easy to produce. This requires more advanced computer systems and integration with existing computer systems. The paper discusses the parameters an improvement project in laboratory medicine can evaluate its results after. There are currently no standardized quality parameters in clinical chemistry. The parameters used in this study that proved to be the most suitable to be used continuously in the short term was the response times, staffing and reagent costs. In the long...
Primary health care encompasses laboratory testing where the entire analysis is performed by heal... more Primary health care encompasses laboratory testing where the entire analysis is performed by health care professionals in close proximity to the patient. The purpose of this survey was to understand the range of testing performed in primary health care in Sweden. The results obtained from the survey have been compared to data on the same topic published twenty years ago. The most frequently performed analyses in primary health care have barely changed in the last twenty years. For example, hemoglobin and sedimentation rate analyses are still prevalent. The variety of analyses performed in primary health care has increased, however. C-reactive protein is now a commonly performed analysis. Moreover, in this survey, the degree to which laboratories are quality assured and accredited has been investigated. Accreditation and quality assurance of laboratories varies regionally in Sweden with those facilities meeting the criteria varying from 0% in a province to 100%.
Potassium transport was measured in beta-cell-rich islets from ob/ob-mice using the K+-analogue 8... more Potassium transport was measured in beta-cell-rich islets from ob/ob-mice using the K+-analogue 86Rb+. Both tetracaine (0.1 mM) and glibenclamide (0.1 microM) reduced the ouabain-resistant 86Rb+ influx but did not significantly affect the ouabain-sensitive portion (Na+/K+ pump). Tetracaine (0.5 - 1 mM) or glibenclamide (0.2 mM) decreased the 86Rb+ equilibrium content and glibenclamide (1 microM) transiently reduced the 86Rb+ efflux rate but 0.1 mM tetracaine had only a slight effect on this flux rate. The results suggest that a change in ouabain-resistant (passive) K+ fluxes, but not the Na+/K+ pump, is involved in stimulation of insulin secretion by glibenclamide and tetracaine. Both drugs may exert similar effects on the beta-cell plasma membrane.
Scandinavian Journal of Clinical and Laboratory Investigation, 1997
Recent studies have indicated that serum and plasma cystatin C are better markers for glomerular ... more Recent studies have indicated that serum and plasma cystatin C are better markers for glomerular filtration rate (GFR) than serum creatinine, ubiquitously used for this purpose. To fully exploit the value of serum and plasma cystatin C as GFR markers, reliable age and sex-correlated reference intervals are required. The present study comprised cystatin C determinations in plasma and sera from 259 individuals from a well-defined area in the southernmost part of Sweden. From demographic lists two men and two women were randomly selected from each one-year birth cohort above 20 years of age. No sex differences were found for plasma and serum cystatin C, whereas an increase in the cystatin C levels with age was noted, corresponding to the known age-related decrease in GFR. The following reference intervals are recommended for practical clinical use: S-Cystatin C (both sexes): 20-50 years, 0.70-1.21 mg l-1 and 50+ years, 0.84-1.55 mg l-1. The same samples were also used for determination of beta 2-microglobulin levels in order to calculate reference intervals for the beta 2-microglobulin/cystatin C-ratio, which is a more distinct marker for cell proliferation, particularly lymphoproliferation, than is the serum level of beta 2-microglobulin alone, since the ratio should be virtually uninfluenced by GFR. The beta 2-microglobulin/cystatin C-ratios were uninfluenced by sex and age and 1.45-2.43 is recommended as the serum reference interval for practical clinical use. Serum creatinine was determined in the same samples and the creatinine level was found to be strongly influenced by sex and weakly by age.
Thrombomodulin is an endothelial cell membrane glycoprotein that promotes protein C activation. I... more Thrombomodulin is an endothelial cell membrane glycoprotein that promotes protein C activation. It has been clearly demonstrated that the anticoagulant functions of the protein C system are important in the prevention of thromboembolic disease. Patients with protein C or protein S deficiency and/or resistance to activated protein C (APC resistance) are at higher risk for developing thromboembolic disease. The first mutation in the thrombomodulin gene was discovered in an American patient suffering from pulmonary embolism at the age of 45 (Ohlin and Marlar 1995). Here we report a case of sagittal sinus thrombosis in a 42-year-old Swedish woman. She was found to carry a heterozygous point mutation changing G127 to A, predicting an Ala25 to a Thr change in the mature thrombomodulin protein. This mutation was also found in her 16-year-old daughter, who so far has not suffered from any thrombotic events. The patient had no other detectable prothrombotic genetic defects associated with th...
The diabetogenic action of alloxan on pancreatic beta-cells is thought to be mediated by hydroxyl... more The diabetogenic action of alloxan on pancreatic beta-cells is thought to be mediated by hydroxyl radicals. The initial attack of the radicals is probably at the plasma membrane level. Diethyldithiocarbamate (DDTC) and its dimer disulfiram (Antabuse) have recently been shown to protect against damage by free radical generating agents. The ability of DDTC and disulfiram to inhibit alloxan-induced dye accumulation of isolated ob/ob mice islet beta-cells was therefore studied. Evans blue was used as an indicator of plasma membrane permeability. DDTC (100 microM 1 mM) but not disulfiram (100 microM 1 mM) inhibited alloxan-induced dye uptake of beta-cells. The effect of DDTC on oxygen consumption in a mixture of reduced glutathione (GSH), alloxan and FeSO4 was studied with a Clark-type oxygen electrode. DDTC (20, 100 microM) had no effect on the oxygen consumption of this mixture. It is suggested that the DDTC inhibition of alloxan-induced dye uptake of isolated beta-cells takes place at a step beyond the generation of free radicals.
The ultrastructure of beta-cell granules was examined after fixation of isolated mouse islets in ... more The ultrastructure of beta-cell granules was examined after fixation of isolated mouse islets in fixatives of various compositions. Islets fixed in glutaraldehyde with or without post-fixing in osmium tetroxide, or in osmium tetroxide alone, exhibited the classical picture of electron-dense core surrounded by a lucid halo. After fixation in potassium permanganate, with or without post-fixing in osmium, the secretory vesicle was often completely filled with a fairly homogeneous material; the vesicle membrane was distinct in outline. When glutaraldehyde-fixed beta-cells were stained according to Rambourg to visualize reducing groups, possibly carbohydrates, two distinct classes of secretory granules were observed, one darkly stained and one faintly, without any noticeable precipitation of silver; the perigranular halo remained unstained in both types of granules. The perigranular halo of aldehyde and osmium fixed beta-granules also remained unstained in cells exposed to the osmiophilic amine, 5,6-dihydroxytryptamine.
The re-aggregation of dispersed islet cells from non-inbred ob/ob-mice was studied by light and e... more The re-aggregation of dispersed islet cells from non-inbred ob/ob-mice was studied by light and electron microscopy. After 3 days of culture, spontaneously formed aggregates with more than 95% beta-cells were up to 0.5 mm in diameter and exhibited a high degree of viability on dye exclusion tests. In comparison with cultures at 1 or 3 mM D-glucose, or 1 mM D-glucose in combination with 19 mM 3-0-methyl-D-glucose, aggregates formed in 20 mM D-glucose were more closely packed, had a smoother circumference with elongated peripheral beta-cells, and exhibited well developed micro-villi in localized intercellular widenings. A stereological analysis of electron micrographs showed that beta-cells aggregated at 20 mM D-glucose exhibited the same individual profile area but a significantly lower form factor, and a significant reduction in granule volume density as compared with aggregates at 3 mM D-glucose. It is concluded that D-glucose has morphogenetic effects on both the cellular and the ...
Potassium and chloride transport were measured in P-cell-rich islets from oblob-mice using Wand 8... more Potassium and chloride transport were measured in P-cell-rich islets from oblob-mice using Wand 86Rb+ (K+-analogue). Reduction of the osmolarity from the normal 317 mosm 1-I to 180 mosm 1-1 reduced the apparent content of K+ and C1-. Hypo-osmolarity had no effect on the ouabain-sensitive portion of the Rb+ influx (Na+/K+ pump), but reduced the ouabain-resistant portion of the influx. Hypo-osmolarity also strongly increased the Rb+ efflux rate. Both tetracaine (0.5 mM) and glibenclamide (20 p~) , which increase the osmotic resistance of pancreatic P cells, significantly potentiated the reduction in apparent K+ content induced by hypo-osmolarity. This study suggests that the volume regulation in pancreatic 1 cells is partly due to K+ and C1-flux and that glibenclamide and tetracaine increase the osmotic resistance of the P cells by affecting such ion transport.
Dispersed islet cells from noninbred ob/ob mice were cultured for 3 days with 3 or 20 mM D-glucos... more Dispersed islet cells from noninbred ob/ob mice were cultured for 3 days with 3 or 20 mM D-glucose and silver stained according to Rambourg et al. Two tinctorial subsets of dark and light intracellular granules were analyzed by morphometry at the ultrastructural level. The two types of granules were similar in size and shape. However, with 3 mM glucose the dark granule cores were surrounded by larger vesicles than the light granules. With 20 mM glucose, both types of granule vesicles and cores became smaller and dark-granule cores became more rounded, compared with cultures with 3 mM glucose. The higher glucose concentration also induced a marked decrease in the number (-84%) and volume density (-90%) of dark granules. In contrast, the number of light granules increased (+60%) with maintenance of their volume density. We suggest that the dark Rambourgpositive and the light Rambourg-negative p-cell granules are functionally distinct subsets. The dark granules are probably engaged in insulin discharge. We discuss the unclear role of the light granules with a view to previously postulated heterogeneities of the insulin granule pool and their significance for exocytosis and intracellular hormone degradation. Diabetes 37:194-99,1988 F unctional as well as morphological studies (1-4) have indicated that the secretory granules in the pancreatic p-cells represent a heterogenous population of organelles. In standard electron micrographs, the granules show a continuum in electron density from grey to dark. However, after silver staining according to Rambourg et al. (5), two fairly distinct pools of granules were observed, one very light and one black (6). The mean-From the
According to the National Board of Health and Welfare, SOSFS 2005:12, it is required that the car... more According to the National Board of Health and Welfare, SOSFS 2005:12, it is required that the caregiver adheres to his work through following stated objectives. Formulating goals in health care requires careful consideration. Goals must be measurable and include many different aspects of the project. Each improvement project is unique and should be directly related to the resources allocated to the project. A major problem for continuous monitoring is to select parameters that provide sufficient information and are easy to produce. This requires more advanced computer systems and integration with existing computer systems. The paper discusses the parameters an improvement project in laboratory medicine can evaluate its results after. There are currently no standardized quality parameters in clinical chemistry. The parameters used in this study that proved to be the most suitable to be used continuously in the short term was the response times, staffing and reagent costs. In the long...
Primary health care encompasses laboratory testing where the entire analysis is performed by heal... more Primary health care encompasses laboratory testing where the entire analysis is performed by health care professionals in close proximity to the patient. The purpose of this survey was to understand the range of testing performed in primary health care in Sweden. The results obtained from the survey have been compared to data on the same topic published twenty years ago. The most frequently performed analyses in primary health care have barely changed in the last twenty years. For example, hemoglobin and sedimentation rate analyses are still prevalent. The variety of analyses performed in primary health care has increased, however. C-reactive protein is now a commonly performed analysis. Moreover, in this survey, the degree to which laboratories are quality assured and accredited has been investigated. Accreditation and quality assurance of laboratories varies regionally in Sweden with those facilities meeting the criteria varying from 0% in a province to 100%.
Potassium transport was measured in beta-cell-rich islets from ob/ob-mice using the K+-analogue 8... more Potassium transport was measured in beta-cell-rich islets from ob/ob-mice using the K+-analogue 86Rb+. Both tetracaine (0.1 mM) and glibenclamide (0.1 microM) reduced the ouabain-resistant 86Rb+ influx but did not significantly affect the ouabain-sensitive portion (Na+/K+ pump). Tetracaine (0.5 - 1 mM) or glibenclamide (0.2 mM) decreased the 86Rb+ equilibrium content and glibenclamide (1 microM) transiently reduced the 86Rb+ efflux rate but 0.1 mM tetracaine had only a slight effect on this flux rate. The results suggest that a change in ouabain-resistant (passive) K+ fluxes, but not the Na+/K+ pump, is involved in stimulation of insulin secretion by glibenclamide and tetracaine. Both drugs may exert similar effects on the beta-cell plasma membrane.
Scandinavian Journal of Clinical and Laboratory Investigation, 1997
Recent studies have indicated that serum and plasma cystatin C are better markers for glomerular ... more Recent studies have indicated that serum and plasma cystatin C are better markers for glomerular filtration rate (GFR) than serum creatinine, ubiquitously used for this purpose. To fully exploit the value of serum and plasma cystatin C as GFR markers, reliable age and sex-correlated reference intervals are required. The present study comprised cystatin C determinations in plasma and sera from 259 individuals from a well-defined area in the southernmost part of Sweden. From demographic lists two men and two women were randomly selected from each one-year birth cohort above 20 years of age. No sex differences were found for plasma and serum cystatin C, whereas an increase in the cystatin C levels with age was noted, corresponding to the known age-related decrease in GFR. The following reference intervals are recommended for practical clinical use: S-Cystatin C (both sexes): 20-50 years, 0.70-1.21 mg l-1 and 50+ years, 0.84-1.55 mg l-1. The same samples were also used for determination of beta 2-microglobulin levels in order to calculate reference intervals for the beta 2-microglobulin/cystatin C-ratio, which is a more distinct marker for cell proliferation, particularly lymphoproliferation, than is the serum level of beta 2-microglobulin alone, since the ratio should be virtually uninfluenced by GFR. The beta 2-microglobulin/cystatin C-ratios were uninfluenced by sex and age and 1.45-2.43 is recommended as the serum reference interval for practical clinical use. Serum creatinine was determined in the same samples and the creatinine level was found to be strongly influenced by sex and weakly by age.
Thrombomodulin is an endothelial cell membrane glycoprotein that promotes protein C activation. I... more Thrombomodulin is an endothelial cell membrane glycoprotein that promotes protein C activation. It has been clearly demonstrated that the anticoagulant functions of the protein C system are important in the prevention of thromboembolic disease. Patients with protein C or protein S deficiency and/or resistance to activated protein C (APC resistance) are at higher risk for developing thromboembolic disease. The first mutation in the thrombomodulin gene was discovered in an American patient suffering from pulmonary embolism at the age of 45 (Ohlin and Marlar 1995). Here we report a case of sagittal sinus thrombosis in a 42-year-old Swedish woman. She was found to carry a heterozygous point mutation changing G127 to A, predicting an Ala25 to a Thr change in the mature thrombomodulin protein. This mutation was also found in her 16-year-old daughter, who so far has not suffered from any thrombotic events. The patient had no other detectable prothrombotic genetic defects associated with th...
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Papers by Lena Norlund