Biomedical subjects

A Nilsson

Publications and source records attributed to A Nilsson.

628 records · Page 35Linked to original sources

PubMedDate not supplied

Singlet oxygen energy illumination during moderate cold ischemia prolongs the survival of concordant hamster xeno-heart transplants.

INTRODUCTION: Singlet oxygen energy (SOE) is a potent inhibitor of reactive oxygen species (ROS) in vitro and in vivo in certain dose ranges and can improve the levels of high-energy phosphates (HEP) in concordant hamster xeno-heart transplants. Some data indicate that a certain degree of cold ischemia (CI) might be beneficial to xenotransplants. We investigated if SOE illumination of hamster xeno-hearts during moderate cold ischemia (CI) improved graft survival. MATERIALS AND METHODS: Eighteen hearts from Golden Syrian hamsters (70 to 80 g) were subjected to 8 hours of CI in cold (+4 degrees C) saline solution (NaCL, 0.9%) before heterotopic cervical transplantation to Lewis rats (220 g). Among the treatment group (n = 8), SOE was produced by illuminating the hearts for 10 minutes every 30 minutes with photons at lambda 634 nm with the Oxylight equipment. Graft function was evaluated every 6 hours after transplantation with digital exam until cessation of heart beats. RESULTS: The graft survival of SOE-illuminated ischemic hamster xenografts was 2.34 +/- 0.56 versus 1.15 +/- 0.37 days in the control group (P < .05). All hearts displayed immediate graft function versus 70% in the controls (NS). CONCLUSIONS: SOE illumination at lambda 634 nm during moderate cold ischemia (+4 degrees C) can improve the survival of concordant hamster xeno-heart transplants. The exact mechanism(s) are currently unknown, but the effect might in part be exerted by a combination of reduced production of ROS and increased oxidative phosphorylation.

Animals↗

PubMedDate not supplied

Effects of lead on the endocrine system in lead smelter workers.

In this study of the effects of lead on the endocrine system, 77 secondary lead-smelter workers (i.e., 62 active and 15 retired) were compared with 26 referents. Lead concentrations were determined in plasma with inductively coupled plasma mass spectrometry (i.e., index of recent exposure), in blood with atomic absorption spectrophotometry, and in fingerbone with K x-ray fluorescence technique (i.e., index of long-term exposure). In addition, pituitary hormones were determined in serum by fluoroimmunoassay, and thyroid hormones and testosterone in serum were determined with radioimmunoassay. Nine lead workers and 11 referents were challenged with gonadotrophin-releasing hormone and thyrotrophin-releasing hormone, followed by measurements of stimulated pituitary hormone levels in serum. Median levels of lead in plasma were 0.14 microg/dl (range = 0.04-3.7 microg/dl) in active lead workers, 0.08 microg/dl (range = 0.05-0.4 microg/dl) in retired lead workers, and 0.03 microg/dl (range = 0.02-0.04 microg/dl) in referents (1 microg/dl = 48.3 nmol/l). Corresponding blood lead concentrations were 33.2 microg/dl (range = 8.3-93.2 microg/dl), 18.6 microg/dl (range = 10.4-49.7 microg/dl), and 4.1 microg/dl (range 0.8-6.2 microg/dl), respectively. Respective bone lead levels were 21 microg/gm (range = -13 to 99 microg/gm), 55 microg/gm (range = 3-88 microg/gm), and 2 microg/gm (range = -21 to 14 microg/gm). Concentrations of basal serum hormone (i.e., free thyroid hormones, thyrotrophin, sex hormone binding globulin, and testosterone) were similar in the 3 groups. There were no significant associations between the hormones mentioned herein and blood plasma, blood lead, and bone lead levels. In the challenge test, stimulated follicle-stimulating hormone levels were significantly lower in lead workers (p = .014) than in referents, indicating an effect of lead at the pituitary level. Also, there was a tendency toward lower basal stimulated follicle-stimulating hormone concentrations in lead workers (p = .08). This effect, however, was not associated with blood plasma level, blood lead level, or bone lead level. In conclusion, a moderate exposure to lead was associated with only minor changes in the male endocrine function, particularly affecting the hypothalamic-pituitary axis. Given that sperm parameters were not studied, the authors could not draw conclusions about fertility consequences.

Adult↗

PubMedDate not supplied

Polychlorinated biphenyls, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) and 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p'-DDE) in human plasma related to fish consumption.

Fatty fish species, e.g., salmon and herring, in the Baltic Sea have high levels of polychlorinated biphenyls (PCBs) and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT), and its main metabolite: 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p'-DDE). We determined levels of 10 different PCB congeners, including non- and mono-ortho-PCBs, as well as DDT and DDE, in human blood plasma from 37 subjects with varying intake of fish (0-1 750 g/wk) from the Baltic Sea. With respect to all of the PCB congeners we investigated, as well as for DDT and DDE, there were statistically significant associations with fish intake. Thus, fish from the Baltic Sea is a major source of exposure to these compounds in Swedes. Polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) had been determined earlier in 29 of the subjects. The PCB contribution to "dioxin-like" effects among high consumers of fish (calculated as Nordic TCDD equivalents) was almost 80%, whereas that from PCDD and PCDF was only 20%.

Adult↗

PubMedDate not supplied

Addition of cultured Schwann cells to tendon autografts and freeze-thawed muscle grafts improves peripheral nerve regeneration.

The effects of addition of Schwann cells on peripheral nerve regeneration through a novel graft material-the tendon autograft-and a conventional freeze-thawed muscle graft, were studied in the rat sciatic nerve. Adult Schwann cell cultures were established from predegenerated nerves. The Schwann cells were added to the autologous grafts by coculture (tendon autograft) or injection (freeze-thawed muscle graft). Both graft types supported adherence of the added Schwann cells. Addition of cultured Schwann cells to the two different graft models improved regeneration by increasing the rate of axonal outgrowth as compared with similar grafts without added cells.

Animals↗

PubMedDate not supplied

Activation of neutral sphingomyelinase participates in ethanol-induced apoptosis in Hep G2 cells.

The mechanism underlying ethanol-induced apoptosis in liver cells is not clear. Sphingomyelin (SM) metabolism is a novel signal transduction pathway that has an impact on apoptosis in many cell types. We investigated whether the SM pathway is involved in ethanol-induced apoptosis in the liver. Hep G2 cells were treated with ethanol followed by assaying apoptosis, sphingomyelinase (SMase) activity, caspase-3 activity, and the changes of SM content in the cells. We found that ethanol dose-dependently increased apoptosis and the effect was accompanied by increases of caspase-3 activity and neutral SMase activity. At concentrations of 80 and 160 mM, ethanol significantly increased caspase-3 activity by 120% and neutral SMase activity by 24%. The activity of acid SMase was only slightly increased without statistical significance. C(2)-ceramide, the exogenous SM metabolite, mimicked the effects of ethanol on apoptosis and caspase-3 activation. When the SM content was determined 24 h after treatment with ethanol, its level was 15% lower than that of controls. The results indicate that metabolism of SM triggered by neutral SMase participates in ethanol-induced apoptosis in Hep G2 cells and activation of caspase-3 is involved in the apoptotic pathway.

Apoptosis↗

PubMedDate not supplied

Gallstone ileus demonstrated by CT.

OBJECTIVE: The appearance and evolution of gallstone ileus as seen by CT are reported. MATERIALS AND METHODS: CT examination was performed on three patients with unspecific abdominal pain. In one patient sequential investigations were performed over 7 months. RESULTS: In all cases the gallbladder was greatly distorted, contained air, and was in direct continuity with a thickened duodenal wall. The gallstone was detected in the small bowel in all cases. In one patient sequential CT examinations over several months demonstrated the evolution from uncomplicated gallstone disease to cholecystitis and finally to perforation of the gallstone into the duodenal bulb. CONCLUSION: Awareness of the CT findings in gallstone ileus may result in more rapid diagnosis and treatment, which may lead to a decrease in the rather high morbidity and mortality seen in this disease.

Aged↗

PubMedDate not supplied

Intestinal retinol esterification and serum retinol in children with cystic fibrosis.

Children with cystic fibrosis (CF) often have a poor vitamin A status. We found in the present work a reduced level of serum retinol in older children with this disease. As retinol enters intestinal lymph as retinyl esters, the enzyme acyl-CoA:retinol acyltransferase (ARAT) may be of importance for retinol absorption. We have assayed ARAT activity in duodenal mucosal homogenate from children with CF. There was a large variation within the group. However, mean ARAT activity was not significantly decreased, as compared with controls. Thus, the lack of pancreatic enzymes probably is the main reason for reduced vitamin A absorption in CF. In celiac disease and in lactose intolerance--both mucosal disorders--a significant reduction of mean ARAT activity was found.

Acyltransferases↗

PubMedDate not supplied

Investigations of 90Sr in dogs. I. Pathogenesis of radiation-induced bone tumors.

Purebred beagle dogs given 90Sr and unirradiated controls were studied for over two decades. Pregnant females were fed different doses of 90Sr from day 21 post-conception until the offsprings reached an age of 540 days. In an additional experiment two dose levels were given in a single intravenous dose to dogs 540 days old. Radiographically the earliest skeleton lesions were characterised by small linear, solitary, cortical lucencies. These as well as tumors were more frequently noted in the higher exposure levels. They affected the appendicular skeleton almost as frequently as the axial skeleton. The lesions were predominantly found in the diaphysis, at the angle and near the acetabulum in the tubular bones, mandible and pelvis, respectively. The lesions within the diaphysis originated in the cortical bone. Histologically these lesions were characterised by different types of porosities. These could be empty or filled by a defect and/or immature, dysplastic fibrous repair tissue, within the frame of which malignant transformations seemed to take place as evidenced by malignant clones and micro-osteosarcomas. A comparison is made of the histologic events in dogs and mice and a tentative pathogenesis of 90Sr induced bone tumors is discussed.

Aging↗

PubMedDate not supplied

Expression and activity of DNA-dependent protein kinase in normal human leukocytes.

BACKGROUND: DNA-PK is a serine/threonine protein kinase that has been shown to play an important role in V(D)J recombination, Ig switching and DNA double strand break (DSB) repair. We have investigated DNA-PK in whole cell extracts from B and T lymphocytes, monocytes and granulocytes and the effects of phorbolmyristate acetate (PMA) and Concanavalin A (Con A) on DNA-PK in B and T lymphocytes. MATERIALS AND METHODS: Lymphocytes were separated from human peripheral blood using the E-rosette technique and DNA-PK was analysed using Western blot, DNA-PK kinase activity assay and flow cytometry. RESULTS: The levels of DNA-PK activity and content varied among the leukocytes. PMA and Con A stimulation consistently increased both DNA-PK activity and content in B lymphocytes as cells entered the S phase. Up-regulation could normally not be seen in T lymphocytes, although cells entered the S phase following PMA and Con A stimulation. CONCLUSION: Mitogenic stimulation up-regulates DNA-PK activity and protein expression in B lymphocytes. T lymphocytes show interindividual differences in DNA-PK. Regulation of DNA-PK is not strictly cell cycle dependent for all cell types.

Adult↗

PubMedDate not supplied

Human papilloma virus (HPV) and p53 immunostaining in advanced tonsillar carcinoma--relation to radiotherapy response and survival.

BACKGROUND: Human papilloma virus (HPV), which is frequently present in tonsillar carcinoma seems to be a prognostically favourable factor for patient survival and also for low risk of relapse. Since HPV may abrogate the function of wild type p53 and hence influence radiosensitivity we attempted to analyse if HPV and p53 status in tonsillar carcinoma affected tumour response to radiotherapy (RT) and patient survival. MATERIALS AND METHODS: Pre-treatment primary tonsillar carcinoma specimens were obtained retrospectively from 40 patients, 21 complete responders (CR) and 19 non-complete responders (non-CR) of which 38/40 were stage III and IV tumours. The paraffin-embedded biopsies were analysed for presence of HPV DNA, by general and type specific PCR, and for p53 overexpression by immunohistochemical staining with the murine Mab DO-1. RESULTS: It was possible to analyse HPV in 34 and p53 in 39 patients. Presence of HPV DNA (HPV+) and p53 immunostaining (p53+) were not correlated with response to RT, since 8/18 CR patients and 6/16 non-CR patients were HPV+ and 11/21 CR patients and 8/18 non-CR patients were p53+. A tendency towards a survival benefit in patients with HPV+ tumours was observed and this tendency was significant for patients with stage IV HPV + tumours (p = .0431), and in particular HPV+/p53- cancers (p = .0195). A difference in survival between patients with p53+ cancer as compared to patients with p53- lesions was not demonstrated. In conclusion, although presence of HPV and p53 immunoreactivity in tonsillar carcinoma could not be related to RT response, determination of HPV and p53 status may still prove useful as predictive/prognostic markers.

Biomarkers, Tumor↗

PubMedDate not supplied

Levels of angiogenic peptides in sera from patients with carcinoid tumours during alpha-interferon treatment.

BACKGROUND: Alpha-interferon, a known inhibitor of angiogenesis and cell proliferation, is used in the standard treatment of patients with carcinoid tumors. We studied the levels of two angiogenic peptides (bFGF and VEGF) in sera from patients with carcinoid tumours before and during treatment with alpha-interferon. The aim was to investigate if the antitumoral effect of alpha-interferon in these patients could be at least in part explained by a reduction in the measured angiogenetic peptides. PATIENTS AND METHODS: Sera from 29 patients with carcinoid tumours were collected before and during alpha-interferon treatment and analyzed using commercially available ELISA-kits. RESULTS: Interferon alpha treatment did not cause reduction of bFGF and VEGF levels in serum from patients with carcinoid tumours. In fact there was no correlation between changes in bFGF or VEGF levels and treatment effect. CONCLUSION: The action of alpha-interferon does not seem to be mediated by bFGF or VEGF in patients with carcinoid tumours. If alpha-interferon has an anti-angiogenic effect in this patient group, it is probably mediated by angiogenic peptides other than bFGF and VEGF.

Adult↗

PubMedDate not supplied

DNA-dependent protein kinase in leukaemia cells and correlation with drug sensitivity.

We investigated whether the levels of the DNA-dependent protein kinase (DNA-PK) activity and content correlate with drug sensitivity in different tumour materials and if this can be utilised in predicting treatment outcome. DNA-PK activity and expression were investigated in tumour cells from 8 patients with chronic lymphocytic leukaemia (CLL) and 18 patients with acute myeloid leukaemia (AML), using Western blot and DNA-PK kinase activity assay. Tumour cells from the patients were investigated for their drug sensitivity to topoisomerase II inhibitors (doxorubicin and etoposide), DNA reactive agents (melphalan, 4-hydroxycyclophosphamide and cisplatinum), an antimetabolite (cytosine arabinoside) and an antimicrotubule agent (vincristine) by fluorometric microculture cytotoxicity assay (FMCA). Within each group of leukaemia there was a large variation in both DNA-PK activity and DNA-PKcs expression, while the Ku subunits were expressed more homogeneously. In CLL cells, sensitivity to topoisomerase II inhibitors correlated with DNA-PKcs protein expression (r=0.7174, p=0.0452). In AML samples, sensitivity to DNA cross-linking alkylating agents correlated with Ku86 (r=-0.7512, p=0.0031) and Ku70 (r=-0.6134, p=0.0258) expression. Unexpectedly, DNA-PK activity was found to correlate with sensitivity to vincristine in both CLL (r=0.8557, p=0.0067) and AML (r=0.5480, p=0.0228) cells. The results indicate that DNA-PK is not only involved in the recognition of DNA double-strand breaks (DSB), but also other DNA lesions.

Acute Disease↗

PubMedDate not supplied

Is glucose-free bupivacaine isobaric or hypobaric?

Spinal anesthesia with 0.5% glucose-free bupivacaine was given to 20 patients lying in the lateral decubitus position during lumbar injection and for 30 minutes after. The mean maximum level of anesthesia after 30 minutes was Th:8 in the nondependent side and Th:9 in the dependent side. The difference in cephalad level of analgesia between the two sides during the initial 30 minutes was significant. Fourteen patients experienced some degree of hypoalgesia during the initial 30 minutes in the dependent side but not in the nondependent side. The degree of motor blockade also showed significant difference between the dependent and nondependent side except at five minutes. These findings indicate glucose-free bupivacaine 0.5% is hypobaric in clinical conditions.

Anesthesia, Spinal↗

PubMedDate not supplied

Characterisation of the G1/S cell cycle checkpoint defect in lung carcinoma cells with different intrinsic radiosensitivities.

Cell cycle perturbations in three lung carcinoma cell lines (U-1285,U1906 and U-1810) with different intrinsic radiosensitivities (SF2 U-1285 = 0.25, SF2 U-1906 = 0.45, SF2 U-1810 = 0.88) were investigated following x-irradiation. Cell cycle flow calculations showed that the G1-->S-phase transit was accelerated in irradiated compared with untreated U-1285 cells, up to 24 hours postirradiation. In U-1810 cells and U-1906 cells the postirradiation G1-->S transit decreased compared with controls. All three cell lines showed no postirradiation induction of p53 and p21CIP1 proteins. Cyclin E was overexpressed and cyclin E-dependent kinase activity was substantially induced by irradiation in U-1285 cells compared with U-1906 and U1810 cells while p27KIP1 was detected at the highest intensity in U-1810 cells and lowest in U-1285 cells. We hypothesise that the accelerated postirradiation G1-->S transit in U-1285 cells is associated with induction of cyclin E-dependent kinase activity and may account for increased radiosensitivity in these cells.

Carcinoma, Non-Small-Cell Lung↗

PubMedDate not supplied

Spontaneous and radiation-induced apoptosis in lung carcinoma cells with different intrinsic radiosensitivities.

Spontaneous and radiation-induced apoptosis in three lung carcinoma cell lines (U-1285, U-1906 and U-1810) with previously characterised intrinsic radiosensitivities (RS) was assessed by TUNEL-staining, detection of DNA laddering and cleavage of poly-(ADP-ribose) polymerase (PARP). Spontaneous apoptosis was detected at a high level in the radiosensitive U-1285, at an intermediate level in U-1906 and not detected in the radioresistant U-1810 cell line. Radiation-induced apoptosis, assessed by TUNEL assay, was present in U-1285 and U-1906 cells but not in U-1810 cells. To explain these findings, expression of Bcl-2, Bax, c-Myc and RB protein and mutations of the p53 gene were analysed. The ratio Bcl-2/Bax was higher in U-1810 cells compared with U-1285 and U-1906 cells. Overexpression of c-Myc and loss of RB was found in U-1285 cells whereas both U-1906 and U-1810 cells expressed RB and showed lower c-Myc expression. Analysis with sequencing of all p53 exons disclosed mutations in all three cell lines. Thus, apoptosis was a p53 independent process in U-1285 and U-1906 cells. RB loss and overexpression of c-Myc may enhance apoptosis in U-1285 cells. Our data suggest that spontaneous apoptosis may correlate with RS in SCLC.

Apoptosis↗

PubMedDate not supplied

Gamma-glutamyl transferase, intestinal alkaline phosphatase and beta-hexosaminidase activity in duodenal biopsies from chronic alcoholics.

BACKGROUND/AIMS: Gamma-glutamyl transferase (GGT) and intestinal alkaline phosphatase (IAP) are present in the brush border of mucosal absorptive cells in the small intestine. There are few studies on the effect of alcohol consumption on these enzymes. Increased intestinal GGT in biopsy specimens from the duodenum has been described in chronic alcoholics. In experimental animals alcohol effects varies with duration of exposure and with nutritional factors. METHODOLOGY: IAP, GGT and the lysosomal enzyme beta-hexosaminidase (Hex) were examined in duodenal biopsy specimens from 23 defined chronic alcoholics and 33 non alcoholic controls. The results were correlated to serum GGT, alkaline phosphatase, CDT (Carbohydrate Deficient Transferrin) and the villus index. RESULTS: Both the intestinal GGT (0.52 + 0.05 SEM vs. 0.30 + 0.024 SEM microkat/g protein, p<0.0001) and the IAP (22.11 + 2.49 SEM vs. 12.28 + 1.35 SEM microkat/g protein, p=0.0010) were significantly higher in alcoholics than in controls. There was no correlation between intestinal and serum alkaline phosphatase and GGT activity within the two groups. CONCLUSIONS: Chronic alcohol consumption causes increased intestinal GGT and IAP activity in man. No effect on Hex was seen. The enzyme activity in the small intestine did not correlate to serum enzyme activity or to morphological changes in the small intestine.

Adult↗