Biomedical subjects

L Jansson

Publications and source records attributed to L Jansson.

At least 91 records · Page 5Linked to original sources

PubMed1997

To meet with a stroke: patients' experiences and aspects seen through a screen of crises.

The aim of this study was to elucidate the experiences of stroke victims during the course of disease and the first few months after discharge. Ten individuals, recently having suffered their first manifest stroke with lasting neurological symptoms, narrated their experiences and gave their views at two different appointments during the first few months after discharge. A deductive approach was applied, on the basis of the theory of developmental crises. The analyses of the interviews were performed using a phenomenological hermeneutic method inspired by the philosophy of Ricoeur. The analyses disclosed phenomena signifying developmental crises in all the cases, though the crises profiles were marked by the sequelae the individuals suffered after stroke and by the age-specific stages of which they were in the middle. The solution of the crises was from being reached within the period of data collection, as the interviews were performed relatively early after home-coming and the individuals were in the middle of grasping their new situation. The phenomenon "to meet with a stroke' seems to challenge the whole of the individual's being. The study calls attention to the need for awareness of this matter, which should be indicated to a much greater extent in nursing care and education than has been done until to date.

Activities of Daily Living↗

PubMed1997

Nitric oxide and pancreatic islet blood flow after induced portal hypertension in rats.

Portal hypertension (PH) is associated with a hyperdynamic splanchnic circulation, partially mediated by nitric oxide-dependent mechanisms. The aim of the present study was to evaluate the influence of PH and nitric oxide on pancreatic islet blood flow. PH was induced by a calibrated stenosis of the portal vein in male Sprague-Dawley rats. Control were sham-operated. Ten days later pancreatic, duodenal, colonic, and arterial hepatic blood flows were measured with microspheres. All splanchnic blood flow values were markedly increased in the PH rats. The fraction of whole pancreatic blood flow diverted through the islets increased from approximately 5 to 15%. Intravenous administration of the nitric oxide synthase inhibitor NG-nitro-L-arginine (25 mg/kg body weight) in rats with PH 10 min before blood flow measurements decreased pancreatic, duodenal, colonic, and arterial hepatic blood flow to control values. Pancreatic islet blood flow was also decreased, but more markedly than that of the whole pancreas. Pancreatic islet morphology was normal, and the rate of islet cell replication was not influenced. PH induced a preferential increase in pancreatic islet blood flow, which is likely to be associated with an increased production of nitric oxide.

Animals↗

PubMed1997

Mechanisms of defective glucose-induced insulin release in human pancreatic islets transplanted to diabetic nude mice.

We have previously observed that human islets, transplanted under the kidney capsule of hyperglycemic nude mice, show a longlasting impairment in glucose-induced insulin release. To investigate the cause(s) of this phenomenon, we transplanted human islets into normoglycemic or alloxan-diabetic nude mice for a 4- to 6-week period. In a third experimental group, aimed at evaluating reversibility of hyperglycemia effects, diabetic nude mice bearing a human islet graft were cured by a second intrasplenic transplant of mouse islets, and the human islets were exposed to a further 2 weeks of normoglycemia. Four to 6 weeks of hyperglycemia induced a severe impairment of glucose- and arginine-induced insulin release, as demonstrated by perfusion of the graft-bearing kidney. This defective release was not restored by a subsequent 2-week period of normoglycemia, and it was accompanied by normal (pro)insulin biosynthesis, glucose oxidation, and expression of insulin messenger RNA. Taken together with our previous study, these observations indicate that impaired glucose metabolism, depletion of insulin messenger RNA, decreased (pro)insulin biosynthesis, increased glycogen accumulation, and depletion of insulin reserves cannot explain the deleterious effects of the diabetic state on human islet insulin release. This, and the similar inhibition of glucose- and arginine-induced insulin release, suggest that prolonged hyperglycemia may exert its deleterious effect on insulin release at a step distal to closure of ATP-sensitive K-channels.

Adult↗

PubMed1997

Islet capillary blood pressure increase mediated by hyperglycemia in NIDDM GK rats.

This study was performed to measure pancreatic islet capillary pressure under basal conditions and after an acute glucose stimulation of insulin release in normal rats. In addition, the islet capillary pressure was estimated in GK rats, an animal model of NIDDM. Hydrostatic pressure in single pancreatic islet capillaries was determined in vivo by direct measurement using the micropuncture technique. The pancreatic islets were visualized by injection of neutral red. This intravital staining had no effect on islet function, whole pancreatic and islet blood flow, and capillary blood pressure in the exocrine pancreas. Islet capillary blood pressure in normoglycemic Wistar F rats was estimated at 3.1 +/- 0.3 mmHg (n = 15). Administration of D-glucose (1 g/kg) doubled this value, whereas no effect was seen after injection of an equimolar dose of the non-metabolizable glucose-derivative 3-O-methyl glucose. In GK rats, basal islet capillary blood pressure was increased (5.7 +/- 0.4 mmHg; n = 10; P < 0.001) when compared with the control Wistar F rats. Reduction of blood glucose levels in GK rats with phlorizin treatment showed this increased basal islet capillary pressure in GK rats to be glucose dependent and reversible. In the present study, we have for the first time shown that both acute and chronic hyperglycemia augment islet capillary pressure. The effects of a chronically increased islet capillary pressure on long-term islet function remain to be determined.

3-O-Methylglucose↗

PubMed1997

Children's dental health in Europe.

"Children's Dental Health in Europe" is a collaborative study of a total of 3200 children, comprising samples of 5- and 12-year-old children from eight EU-countries [Belgium, Germany, Greece, Ireland, Italy, Scotland (United Kingdom), Spain and Sweden] who have undergone clinical examination by well calibrated dentists. This study analyses the influence of a number of sociodemographic factors on the dental health of the actual children. Father's and/or mother's occupational status was used to determine the social class of the family, after construction of a family-social class variable, SocFam, and the accuracy of this variable was tested. In 15 of the 16 samples, both treatment provided and unmet treatment need were higher in children from low social class. The treatment need in children from low social class was significantly greater in the Belgium, German, Greek and Italian 5-year-old samples. The differences in both treatment need and treatment already received for children from high respectively low social class were significant in the Scottish and Spanish 12-year-old samples. Taking into account the total material of 1600 children in each age-group, risk indicators for caries, identified by logistic and multiple regression analyses, were social class of the family, the mother's smoking habits, and in the 5-year-olds the number of siblings.

Adult↗

PubMed1997

Interactory effect between marginal plaque and subgingival proximal restorations on periodontal pocket depth.

The purpose of the present study was to investigate the influence of plaque on periodontal pocket depth adjacent to proximal amalgam restorations after non-surgical periodontal treatment. From 120 randomly selected patients 200 proximal premolar- or molar sites with subgingival restorations (test sites) and 200 contralateral unrestored sites within the same patient (control sites) were included if plaque was present on test as well as on control sites. At baseline the periodontal mean pocket depth adjacent to subgingival restorations were found to be significantly deeper (0.25 mm) than for control sites. After treatment, 24% of the initially subgingivally located restorations were registered as supragingival restorations. The differences according to mean pocket depth between supragingival restorations and corresponding control sites after treatment were found to be statistically non-significant. At reexamination mean pocket depth adjacent to proximal restorations with plaque were significantly deeper than their contralateral unrestored sites (mean difference 0.34 mm), while a non-significant difference was calculated for subgingival restorations without plaque. Subgingival restorations with their apical borders still located subgingivally after periodontal treatment should be regarded as a risk factor in periodontitis progression. Consequently, placement of the restoration margin supragingivally is recommended, especially in periodontitis-prone patients with an insufficient plaque control.

Adult↗

PubMed1997

Periodontal healing in horizontal and vertical defects following surgical or non-surgical therapy.

The aim of the present study was to investigate any relationship between the level of oral hygiene and probing pocket depth reduction over time after periodontal treatment in sites with either vertical or horizontal destructions. The investigation was conducted as a retrospective study on a 3-year consecutive referral population of periodontitis-prone patients based on full-mouth oral radiographic examinations, probing pocket depth registrations and plaque scores. The analyses were performed on a final sample of 3064 sites in 107 patients with regression analysis after adjusting for dependence within the patient. Probing pocket depth was significantly less reduced over time in sites with vertical destructions compared to sites with horizontal destructions following non-surgical treatment. Furthermore, the difference in probing pocket depth reduction between vertical and horizontal defects following non-surgical treatment increased over time in sites with plaque compared to sites without plaque, thus reflecting the importance of the patient's plaque control, especially in sites with vertical destructions. However, the difference in probing pocket depth reduction between vertical and horizontal defects did not increase over time for surgically treated teeth, a finding which probably can be attributed to a more thorough debridement of vertical defects during surgery and/or osteoplasty/osteoectomy limiting the surface area upon which a long junctional epithelium can form, which may facilitate recurrence of a periodontal pocket.

Adult↗

PubMed1997

Prognosis and mortality of root-resected molars.

The purpose of the present study was to compare tooth mortality of root-resected molars with that of root-filled, single-rooted teeth. Survival rates were 68% for root-resected molars and 77% for root-filled single-rooted teeth over a 10-year period. This difference was not statistically significant. Ten-year survival of root-resected molars in patients with radiographic attachment loss in single-rooted teeth of greater than 6 mm was 56% while survival was as high as 89% for root-resected molar patients with radiographic attachment loss in single-rooted teeth less than or equal to 6 mm. In conclusion, the prognosis of root-resection is not poorer than the prognosis of single-rooted teeth with an equal susceptibility to periodontitis, if endodontic conditions and maintenance care are optimal.

Adult↗

PubMed1996

Control of parasitemia and survival during Trypanosoma brucei brucei infection is related to strain-dependent ability to produce IL-4.

We studied non-MHC gene-dependent expression of a number of cytokines in relation to host defense and survival during Trypanosoma brucei brucei (Tbb) infection in mice. In particular, the role of IL-4 was explored with use of genomically IL-4-disrupted mice and in vivo Ab blocking. Splenocytes from MHC-identical B10.Q (relatively resistant) mice showed day 5 postinfection higher numbers of IL-4 mRNA expressing cells than C3H.Q (highly susceptible). A trypanosome-derived lymphocyte triggering factor, which is released by Tbb to polyclonally activate CD8+ T cells, stimulated naive splenocytes in vitro to a higher IL-4 response in B10.Q than in C3H.Q mice. The C3H.Q mice developed an extremely high parasitemia, showed a low Ab response against the variant surface glycoprotein (VSG), and had a mean survival time of 42 days. Conversely, B10.Q mice had lower parasitemia, mounted higher anti-VSG response, and had a mean survival time of 56 days. Deletion of the IL-4 gene had no influence on the infection in C3H.Q mice, while in B10.Q mice the deletion was associated with lower anti-VSG Ab levels and higher parasitemia. Paradoxically, B10.Q mice with disrupted IL-4 gene survived longer than the wild type. Anti-IL-4 Ab-blocking experiments in vivo displayed an enhanced parasitemia and prolonged survival in infected B10.Q mice. We conclude that 1) a non-MHC gene-related and CD8+-dependent ability to produce IL-4 partly determines the susceptibility to Tbb infection; and 2) IL-4, although involved in controlling the levels of parasitemia by its effects on immunoglobulin synthesis, also can have toxic effects on the animals.

Animals↗

PubMed1996

Influence of the neurotoxin capsaicin on rat pancreatic islets in culture, and on the pancreatic islet blood flow of rats.

The importance of peptidergic nerve fibres for the regulation of whole pancreatic and islet blood flow was studied by administration of the neurotoxin capsaicin. Administration of capsaicin induces an acute release and depletion of mainly substance P and calcitonin gene-related peptide from sensory nerve fibres. When given repeatedly to adult rats for several days, the neuropeptides are irreversibly depleted from the nerve endings. Depletion of substance P was confirmed by immunohistochemical stainings in the present study. A bolus dose of capsaicin (4 micrograms/kg body weight) reduced both whole pancreatic and islet blood flow in anesthetized rats, whereas repeated treatment with capsaicin led to an increase in both pancreatic and islet blood flow. In vitro experiments on isolated islets exposed to capsaicin (0.25 and 2.5 microM) for 4 days showed no effect on beta-cell function. We conclude that peptidergic nerves have an important role for the maintenance of basal vascular tone in both the endocrine and exocrine parts of the pancreas, and may thereby influence the regulation of insulin secretion in rats.

Animals↗

PubMed1996

Reinnervation of transplanted fetal porcine endocrine pancreas. Evidence for initial growth and subsequent degeneration of nerve fibers in the islet grafts.

Syngeneic mouse islets were transplanted under the renal capsule of athymic nude (nu/nu) C57BL/6 mice. Likewise, neonatal rat islets or fetal porcine islet-like cell clusters (ICC) were transplanted into nude mice. The animals were killed at various times after implantation and the graft-bearing kidney was removed. The transplant was processed for microscopic examination with indirect immunofluorescence for neuropeptides and tyrosine hydroxylase, and with acetylcholine esterase staining to visualize nerve fibers in the graft. In all grafts, reinnervation with both afferent and efferent nerve fibers was encountered 20 weeks after transplantation. The pattern of reinnervation was quantitatively and qualitatively independent of the source of the implanted islets. These findings indicate that the pattern of reinnervation depends on the implantation organ and not on any inherent properties of the implanted endocrine cells. In addition, surviving vasoactive intestinal peptide-positive neurons within the fetal porcine ICC demonstrated an active ingrowth of nerve fibers into the ICC graft and the adjacent kidney parenchyma after transplantation. However, 12 or 16-24 months after transplantation, marked atrophy of all types of nerve fibers in the ICC grafts was observed. The reason for this late degeneration of nerve fibers is unknown, but it may be related to a failure to establish functional neural connections.

Animals↗

PubMed1996

Pituitary adenylate cyclase activating polypeptide (PACAP) redistributes the blood within the pancreas of anesthetized rats.

The aim of the study was to evaluate the effects of pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) on splanchnic blood flow in anesthetized rats. For this purpose, either PACAP-38 dissolved in saline or saline alone was injected intravenously 5 (10 nmol/kg body weight (bw) PACAP-38) and 30 min (5 or 10 nmol/kg) before measurements. The blood flow to the whole pancreas, islets, duodenum and colon was then measured with a microsphere technique. The higher dose of PACAP-38 slightly increased blood glucose concentrations at both 5 and 30 min after administration, whereas the lower had no effect. Both doses of PACAP-38 induced a transient initial decrease in mean arterial blood pressure. The lower dose of PACAP-38 decreased fractional islet blood flow 30 min after administration, but did not affect the other blood flows. The higher dose of the peptide (10 nmol/kg bw) caused an increase in whole pancreatic blood flow at both 5 and 30 min after administration, whereas islet blood flow was only increased at the former time. At both time points PACAP-38 redistributed the blood flow within the pancreas in favour of the exocrine pancreas. This resulted in a decreased fractional islet blood flow, i.e., the fraction of whole pancreatic blood flow diverted through the islets. At 5 min after PACAP-38 administration duodenal blood flow was decreased, whereas after 30 min no effects on duodenal or colonic blood flow were observed. Administration of a VIP antagonist intravenously (20 nmol/kg bw) decreased the PACAP-38-induced pancreatic blood flow increase and intrapancreatic redistribution. When only the VIP antagonist was given both pancreatic and islet blood decreased in concert. It is concluded that administration of PACAP-38 induces a blood flow increase in the pancreas, preferably in the exocrine parts of the gland, by actions mediated by PACAP-38 receptors shared with VIP.

Amino Acid Sequence↗

PubMed1996

Effects of aminoguanidine on rat pancreatic islets in culture and on the pancreatic islet blood flow of anaesthetized rats.

Aminoguanidine (AG; < or =0.5 mM) is a potent inhibitor of the inducible form of nitric oxide synthase (iNOS) and, at higher concentrations, is also able to prevent advanced glycosylation of proteins. Due to these properties, AG might be an interesting therapeutic compound for prevention of the development of diabetes and for prevention of diabetes complications. In the present study, we examined the effect of AG (0.1, 0.5, 1.0, 5.0, or 10 mM) on prolonged in vitro culture of isolated rat pancreatic islets. Furthermore, the acute effect of AG on pancreatic and islet blood flow in anaesthetized rats was studied with a microsphere technique. Culture for 6 days of pancreatic islets at either 11.1 mM or 28 mM glucose, in the presence of 0.1-1.0 mM AG, was not toxic to the islet cells or impaired insulin secretion. However, when islets were cultured for 8 days with the addition of 5 mM AG at 11.1 mM or 28 mM glucose, a 50% inhibition of glucose-stimulated insulin release was observed. Rats injected intravenously with AG (1, 10, or 50 mg/kg body weight) had a decreased pancreatic blood flow 30 min later. Glucose injection (1 g/kg body weight) increased the islet blood flow, and this effect was not attenuated by AG. The present data suggest that AG, when used in concentrations that inhibit iNOS, can affect pancreatic blood flow, but appears not to be directly harmful to beta-cell function.

Animals↗

PubMed1996

L-arginine and pancreatic islet blood flow in anesthetized rats.

The aim of the present study was to see if L-arginine, which induces insulin release and is a precursor of the endothelial-derived relaxing factor nitric oxide, affects whole pancreatic and/or islet blood flow. For this purpose, anesthetized male Sprague-Dawley rats were injected intravenously with either saline or L-arginine (25, 100 or 250 mg/kg body weight). All doses of arginine caused a slight increase in blood glucose concentration, while the highest dose (250 mg/kg body weight) also increased insulin concentration. However, no changes in either mean arterial blood pressure, whole pancreatic or islet blood flow could be discerned with any of the doses of arginine used. It is concluded that insulin release is not necessarily associated with an increased islet blood perfusion.

Animals↗

PubMed1996

Blood flow regulation in the transplanted fetal endocrine pancreas. Acquisition of a nitric oxide-dependent glucose-induced increase in blood flow.

Islet-like cell clusters (ICCs) were prepared from the fetal porcine pancreas by a culture technique. The ICCs (approximately 500) were implanted under the left renal capsule of nude (nu/nu) C57BL/6J mice. Six weeks, months, 12 months, or 16-24 months later, the animals were anesthetized and the blood flows to the xenogeneic islet graft and the adjacent kidney parenchyma were measured with laser-Doppler flowmetry. After the blood flow measurements, the graft-bearing kidneys were prepared for enzyme and immunohistochemistry. The blood perfusion of the graft was higher than that of the kidney at all times investigated. Intraperitoneal administration of glucose caused only slight and parallel changes in renal and graft blood flows 6 weeks, 6 months, or 12 months after transplantation. However, in all but 1 animal (n=16) transplanted >16 months before the blood flow measurements, glucose caused a marked increase in graft blood flow but did not affect renal blood flow. Injection of 2-deoxy-glucose also increased graft blood perfusion in animals transplanted > 16 months earlier (n=5). Treatment with NG-monomethyl-L-arginine (n=6), an inhibitor of nitric oxide synthase, prevented this glucose-induced flow increase. Nicotinamide adenine dinucleotide phosphate diaphorase histochemistry revealed nitric oxide synthase only in the endothelium and media of graft arterioles in animals in the oldest age group. Thus, with the passage of time after implantation, the grafted xenogeneic ICCs seem to achieve an autonomous blood flow regulation, different from that of the implantation organ. The reactivity to an increment in blood glucose concentration in the graft is similar to that seen in native islets in the pancreas but is not present until >16 months after implantation. The mechanisms for the glucose-induced blood flow increase are obscure but probably depend on local release of nitric oxide within graft arterioles.

Animals↗

PubMed1996

Microsphere distribution in the pancreas of anesthetized rats. Alloxan stimulates the blood flow to all islets whereas glucose only affects the blood perfusion of a subgroup of islets.

CONCLUSION: Islet blood flow stimulation induced by alloxan leads to an increased blood perfusion in all islets, whereas glucose induces a flow increase only in a subgroup of islets. BACKGROUND: The aim of the present study was to investigate if an increased islet blood flow was associated with an enhanced total number of perfused islets, or whether only a subgroup of the islets increased their blood flow. METHODS: For this purpose, the whole pancreatic and islet blood flow was measured with a microsphere technique (4.5 x 10(5) microspheres/kg body wt) in anesthetized Sprague-Dawley rats. Blood flow measurements were made 3 min after an i.v. injection of 1 mL of saline, alloxan (75 mg/kg body wt), or D-glucose (300 mg/mL). RESULTS: Alloxan reduced whole pancreatic blood flow by 50%, but almost doubled islet blood flow. Glucose did not affect whole pancreatic blood flow, but increased islet blood flow 100%. Approximately 10% of the islets in control and glucose-injected rats contained microspheres, compared with about 25% in alloxan-injected rats (P < 0.001). When the islets containing a certain number of microspheres were compared, alloxan induced a homogeneous shift of the curve to the right, i.e., increased the number of islets that contained all amounts of microspheres. Glucose preferentially increased only the fraction of islets containing > or = 3 microspheres.

Alloxan↗

PubMed1996

Antenatal 'booking' interviews at midwifery clinics in Sweden: a qualitative analysis of five video-recorded interviews.

OBJECTIVE: To describe antenatal 'booking' interviews as regards content and illuminate the meaning of the ways midwives and expectant parents relate to each other. DESIGN: Content analysis and phenomenological hermeneutic analysis of transcribed texts from five video-recorded antenatal booking interviews. SETTING: Midwifery clinics at five health centres in the context of Swedish primary care. PARTICIPANTS: Five midwives, five pregnant women (less than 14 weeks pregnant) and two expectant fathers. FINDINGS: A variety of content themes and ways of relating were found. Combined themes of biomedical and obstetric content occurred as frequently as the sum of social, emotional, antenatal care and life-style themes. The midwives' ways of relating formed two main themes; considering and disregarding the uniqueness of the expectant parents. The midwives directed the interview through their choice of content themes and the way they related to the expectant parents. The expectant parents mainly shadowed the midwives' content themes and ways of relating. The expectant fathers seemed like strange visitors in the women's world. Two perspectives of antenatal midwifery care, obstetric and parental, operated alternately and in competition within the interviews. KEY CONCLUSIONS: The content and the ways of relating within the interviews seem to be connected and could be understood in the light of Buber's writings on dialogue. IMPLICATIONS FOR PRACTICE: The findings provide a basis for reflection on the education of midwives and the planning, training and implementation of midwifery care at antenatal 'booking' interviews.

Adult↗

PubMed1996

Radiographic evaluation of mandibular posterior implant sites: correlation between panoramic and tomographic determinations.

The purpose of the present study was to compare bone height determinations of implant sites by different radiographic techniques. Available bone height was measured in regions posterior to the mental foramen on panoramic radiographs, and on tomographs where the faciolingual dimension was at least 5mm. The bone heights were recorded at 401 edentulous and dentate sites in 100 patients. The overall mean bone height (m +/- SD) was 11.25 +/- 3.29 mm on panoramic radiographs and 8.81 +/- 3.38 mm on tomographs. The correlation between the two radiographic techniques ranged from 0.36 to 0.91 if the material was stratified according to factors such as height of available bone, age, gender and the presence of teeth. Gender was significantly correlated to panoramic and tomographic measurements in all regions. However, the precision of predicted tomographic measurements by using a linear regression model was not significantly increased by including gender as an explanatory variable. For evaluation of available bone height in mandibular regions posterior to the mental foramen, tomography is recommended for all prospective implant sites.

Adult↗