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Biomedical subjects

O Nilsson

Publications and source records attributed to O Nilsson.

At least 127 records · Page 7Linked to original sources

Expression of two heterologous promoters, Agrobacterium rhizogenes rolC and cauliflower mosaic virus 35S, in the stem of transgenic hybrid aspen plants during the annual cycle of growth and dormancy.

We monitored, for the first time, the activity of two model heterologous promoters, the Agrobacterium rhizogenes rolC and the cauliflower mosaic virus (CaMV) 35S, throughout the annual cycle of growth and dormancy in a perennial species, hybrid aspen. Each promoter was fused to the uidA beta-glucuronidase (GUS) reporter gene and the constructs were introduced into the hybrid aspen genome by Agrobacterium-mediated transformation. Both wild-type and transgenic plants were cultivated under different regimes of photoperiod and temperature to induce passage through one growth-dormancy-reactivation cycle, and at intervals GUS staining was assessed in stem sections. In rolC::uidA transformants, GUS activity in rapidly growing current-year shoots was not only tissue-specific, being localized to the phloem, but also cell-specific at the shoot base, where it was present only in the companion cells. However, during the onset of dormancy induced by short photoperiod, GUS activity shifted laterally from the phloem to include the cortex and pith. After subsequent exposure to chilling temperatures to induce the transition between the dormancy stages of rest and quiescence, GUS activity almost disappeared from all stem tissues, but regained its original phloem specificity and intensity after the shoots were reactivated by exposing them to long photoperiod and high temperatures. In contrast, GUS activity in the stem of 35S::uidA transformants was strong in all tissues except for the vascular cambium and xylem, and did not vary in intensity during the growth-dormancy-reactivation cycle. The lateral shift and increased intensity of GUS activity in the stem of rolC::uidA transformants during dormancy induction was shown to be associated with the accumulation of starch, and to be mimicked by incubating stem sections in sucrose, as well as glucose and fructose, but not sorbitol, prior to the GUS assay. Our results demonstrate that the activities of the rolC and 35S promoters varied in very different, unpredictable ways during the annual cycle of growth and dormancy in a perennial species, and indicate that the spatial and temporal variation in rolC promoter activity that we observed in the stem of transgenic hybrid aspen plants is attributable to cellular and seasonal changes in sucrose content.

Bacterial Proteins↗

Treatment of liver metastases of carcinoid tumors.

Liver metastases imply a major problem in patients with carcinoid tumors. Patients with localized disease should always undergo resection for cure. Patients with distant metastatic disease can also undergo resection for potential cure or symptom palliation because of the slow growth rate of many carcinoid tumors. In patients with the midgut carcinoid syndrome and bilobar hepatic disease we have performed primary surgery to relieve such symptoms as intestinal obstruction and ischemia, followed by successive embolizations of the hepatic arteries to reduce functional tumor burden in the liver. For optimal palliation, all patients with residual tumor were treated by octreotide. In a consecutive series of 64 patients with the midgut carcinoid syndrome we thus attained a 5-year survival rate of 70%. Fourteen of the patients underwent intentionally curative surgery (e.g., primary surgery followed by liver surgery). Of these patients, none died from their tumor disease during the period of study. The value of adjunctive interferon therapy is currently under evaluation.

Antineoplastic Agents, Hormonal↗

Survival of patients with disseminated midgut carcinoid tumors after aggressive tumor reduction.

Sixty-four consecutive patients with disseminated midgut carcinoids were treated during an 8-year period according to a single clinical protocol aimed at aggressive tumor reduction by surgery alone or with subsequent hepatic artery embolization. All patients had markedly elevated urinary 5-hydroxyindoleacetic acid (5-HIAA) levels (581 +/- 79 micromol/24 h) and hormonal symptoms. Fourteen patients (22%) reached anatomic and biochemical cure by surgery alone. At follow-up, the mean 5-HIAA levels were still normal after 69.0 +/- 6. 2 months; two patients had died from unrelated causes. With the introduction of somatostatin receptor scintigraphy, subclinical disease was diagnosed in 7 of these 14 patients. Forty patients with bilobar hepatic disease underwent embolization in combination with octreotide. In this group, 5-HIAA levels were still reduced by 55% after 71 +/- 11 months of follow-up, and the 5-year survival was 56%, estimated from the total death hazard function. After embolization, two subgroups could be identified with marked differences in their long-term response to treatment. Ten patients were not embolized owing to complicating diseases. The 5-year survival for the entire series was 58%. A significantly increased risk of cardiovascular deaths was seen, which underlines the importance of total survival analysis in a disease with multiple hormonal effects. It is concluded that an active surgical approach must be recommended to patients with the midgut carcinoid syndrome. In patients with bilobar hepatic disease, embolization combined with octreotide treatment markedly reduced the 5-HIAA excretion and suggested a prolonged 5-year survival.

Adult↗

Neuroendocrine insights from the laboratory to the clinic.

BACKGROUND: The interaction between adrenergic nerves and enterochromaffin (EC) cells was studied in health and disease using animal models and patients with the midgut carcinoid syndrome. METHODS: The methods included morphological techniques (fluorescence microscopy/cytofluorimetry, electronmicroscopy), experimental models (in vivo/in vitro nerve stimulation, pharmacological analyses, axonal transport, tumor transplantation, tumor cell cultures) and clinical tests (pentagastrin provocation, octreotide scintigraphy). RESULTS: From vagal nerve stimulation studies it was clear that activation of adrenergic fibers could release serotonin (5-HT) from EC cells, which led to the mapping of a vagal adrenergic pathway. Ultrastructurally a direct innervation of EC cells was demonstrated. It was confirmed in vitro that adrenoceptors controlled the release of 5-HT; it was maintained in neoplasia as studied in the tumor models. The tumor cells shared several functional and morphological characteristics with adrenergic neurons and exerted trophic actions on neurons grown in co-culture. CONCLUSIONS: Pentagastrin provocation of 5-HT release in carcinoid patients may be mediated via release of catecholamines from the adrenals in turn activating adrenoceptors on tumor cells. Pretreatment with a somatostatin analog can reduce these reactions and thus minimize the risk for carcinoid crisis during surgery.

Adrenergic Fibers↗

Intraoperative detection of somatostatin-receptor-positive neuroendocrine tumours using indium-111-labelled DTPA-D-Phe1-octreotide.

After injection of 111In-labelled DTPA-D-Phe1-octreotide, intraoperative tumour localisation was performed using a scintillation detector in 23 patients with neuroendocrine tumours. Count rates from suspect tumour lesions and adjacent normal tissue were expressed as a ratio before (Rin situ) and after (Rex vivo) excision. 111In activity concentration ratios of tumour tissue to blood (T/B) were determined in a gamma counter. In patients with midgut carcinoids, (all scintigraphy positive), false Rin situ recordings were found in 4/29 macroscopically identified tumours. T/B ratios were all high (27-650). In patients with medullary thyroid carcinomas (eight out of ten scintigraphy positive), misleading Rin situ results were found in 4/37 macroscopically identified tumours. T/B ratios were lower (3-39) than those seen in midgut carcinoids. Two out of four patients with endocrine pancreatic tumours had positive scintigraphy, reliable intraoperative measurements and very high T/B ratios (910-1500). One patient with a gastric carcinoid had correct measurements in situ and ex vivo with high T/B ratios (71-210). In situ measurements added little information to preoperative scintigraphy and surgical findings using the present detection system. Rex vivo measurements were more reliable. The very high T/B ratios seen in midgut carcinoids and some endocrine pancreatic tumours would be favourable for future radiation therapy via somatostatin receptors.

Carcinoid Tumor↗

Effects of cyclosporin A on bone turnover and on resorption of demineralized bone matrix.

The effects of the immunosuppressive drug Cyclosporin A on orthotopic bone turnover and on the resorption of demineralized bone matrix were studied. In the first experiment, rats were labeled with 3H-proline and 45Calcium and treated with Cyclosporin A 2 mg/kg/day or placebo for 2 weeks. Cyclosporin A treatment resulted in an early transient increase in matrix and mineral turnover in the metaphyseal region of the tibia. Furthermore, Cyclosporin A increased mineral turnover in the diaphyseal part of the tibia, but the matrix turnover was unaffected. No osteopenia was seen after 2 weeks. In the second experiment, prelabeled (3H-proline) demineralized bone matrix from rats and rabbits was implanted in the abdominal walls of growing rats that were treated with Cyclosporin A or placebo. After 4 weeks there was no difference in the remaining activity in the implants from Cyclosporin A or placebo treated rats. Cyclosporin A treatment increased mineral content in demineralized allogenic bone matrix implants by 1/3. In the demineralized xenogenic bone matrix implants, mineral content was 4 times higher in the cyclosporin A treated implants.

Animals↗

Specificity and affinity of 26 monoclonal antibodies against the CA 125 antigen: first report from the ISOBM TD-1 workshop. International Society for Oncodevelopmental Biology and Medicine.

The specificity of 26 monoclonal antibodies against the CA 125 antigen was investigated in two phases of the ISOBM TD-1 workshop. The binding specificity was studied using CA 125 immunoextracted by specific antibodies immobilized on various solid phases, or on the surface of human cell lines. Immunometric assays using all possible antibody combinations were used to study the topography of antibody binding sites on the antigen. We conclude that the CA 125 antigen carries only two major antigenic domains, which classifies the antibodies as OC125-like (group A) or M11-like (group B). One antibody, OV 197, showed binding specificity related to some of the OC125-like antibodies, but was classified into a separate group C. The OC125-like group of antibodies has four subgroups with different binding specificities. These are A1 = OC 125 and K 95, A2 = K 93, A3 = B43.13, and A4 = ZS 33, B27.1 and CCD 247. Binding of nonlabelled OC 125 or K 95 to CA 125 caused a marked increase in binding of labelled OV 197 to the complex. This conformational change was not observed with any other antibody combinations. Antibody B43.13 could form immunometric assay combinations particularly with antibodies of subgroup A4, indicating that the B43.13 epitope is in the periphery of the binding area of OC125-like antibodies. The M11-like group of antibodies is more homogenous with strong cross-inhibition between most antibodies. Only one antibody, ZR 38, would form an immunoassay combination with other M11-like antibodies and thus represents a distinct subgroup. The main group of M11-like antibodies are M 11, ZR 45, MA602-6, K 91, OV 185, K 101, K 90, K 96, K 97, K 102, CCD 242, 145-9, and 130-22. Antibody OV 197 binds to a domain designated C and is unique, as stated above. Antibody pairs from any two of the three groups may be used in immunometric assays. Three antibodies were not studied by complete cross-inhibition due to low affinity (OV 198 and K 100) or lack of material (MA602-1). OV 198 and K 100 are most likely OC125-like and MA602-1 is M11-like. Antibody affinity was estimated with labelled antigen in solution or with antigen absorbed on microtiter wells. Western blot analysis showed staining both in the stacking gel and corresponding to a molecule of 200 kDa. There was a marked difference between the antibodies in their ability to bind to CA 125 immobilized on a membrane. Strongest binding was observed with the M11-like antibodies, particularly M 11, K 96, K 97, MA602-6, 145-9. Antibodies belonging to the subgroup A4 were the only OC 125-like antibodies which reacted well with CA 125 in Western analysis. Digestion of CA 125 with proteolytic enzymes showed it to be particularly sensitive to trypsin cleavage. However, no low molecular weight fragments with preserved immunoreactivity were found.

Animals↗

Histidine decarboxylase expression and histamine metabolism in gastric oxyntic mucosa during hypergastrinemia and carcinoid tumor formation.

Histamine is an important stimulator of gastric acid secretion. In experimental animals, inhibition of acid secretion by long term histamine2 receptor blockade causes hypergastrinemia, proliferation of enterochromaffin-like (ECL) cells, and formation of histamine-producing gastric carcinoids. The aim of this study was to examine the role of gastrin in histamine synthesis and metabolism of the oxyntic mucosa of normal, hyperplastic, and carcinoid-bearing Mastomys natalensis. Administration of exogenous gastrin to normal animals increased histidine decarboxylase (HDC) messenger RNA (mRNA) expression in the oxyntic mucosa within 30 min, indicating that gastrin stimulates histamine synthesis by regulating HDC mRNA abundance. Endogenous hypergastrinemia, induced by short term histamine2 receptor blockade (loxtidine) for 3-29 days, did not induce tumors, but enhanced the expression of HDC mRNA (2- to 4-fold elevated) and histamine contents (2-fold elevated) in the oxyntic mucosa. Long term histamine2 receptor blockade (7-21 months) resulted in sustained hypergastrinemia and ECL tumor formation. Tumor-bearing animals had a 4-fold increase in HDC mRNA expression and histamine contents of the oxyntic mucosa. Urinary excretion of the histamine metabolite methyl-imidazole-acetic acid was 2-fold elevated. Tumor-bearing animals recovering from histamine2 receptor blockade were normogastrinemic and had normal levels of HDC mRNA and histamine in the oxyntic mucosa as well as normal excretion of methyl-imidazole-acetic acid. The results indicate that ECL cell carcinoids developing during hypergastrinemia are well differentiated tumors that respond to high gastrin levels with increased histamine synthesis and secretion.

Animals↗

Systemic radionuclide therapy using indium-111-DTPA-D-Phe1-octreotide in midgut carcinoid syndrome.

A 55-yr-old woman with a midgut carcinoid syndrome due to metastatic spread of an ileal tumor to the liver, paraortic and mediastinal lymph nodes and to the skeleton was given systemic radionuclide therapy with 111In-DTPA-D-Phe1-octreotide. Before therapy, dosimetric calculations were performed on whole-body scintigraphs and 111In retention was shown to be long-lasting. Excretion was mainly seen during the first 24 hr after injection; thereafter whole-body retention remained stationary at 30%. Indium-111 activity in tumor biopsies and blood was measured using a gamma counter. Very high tumor-to-blood ratios were obtained: 150 for the primary tumor and 400-650 for liver metastases, which further justified radiation therapy. Indium-111-DTPA-D-Phe1-octreotide treatment was given on three separate occasions (3.0, 3.5 and 3.1 GBq) 8 and 4 wk apart. After each therapy, the patient experienced facial flush and pain over the skeletal lesions followed by symptomatic relief, even though no objective tumor regression was found radiologically after 5 mo. After initiation of octreotide treatment, there was a 14% reduction of the main tumor marker, urinary 5-HIAA. After three subsequent radionuclide therapies, there was a further 31% reduction of 5-HIAA levels. No adverse reactions, other than a slight decrease in leukocyte counts, were seen. The mean absorbed radiation dose after the three treatments was estimated to be about 10-12 Gy in liver metastases and 3-6 Gy in other tumors, depending on the size and location of the metastases. Assuming internalization of 111In into tumor cells and a radiobiological effect from short range Auger and conversion electrons, there might be a therapeutic effect on the tumor.

Female↗

Immunohistochemical characterization of 22 monoclonal antibodies against the CA125 antigen: 2nd report from the ISOBM TD-1 Workshop.

We evaluated the immunohistological (IH) characteristics of 22 different antibodies that were submitted for study in the frame of the TD-1 ISOBM Workshop on monoclonal antibodies against CA125. Information on relative affinities and epitope similarities was obtained from a parallel immunochemical study. Antibodies were tested at concentrations of 10 and 1 micrograms/ml on frozen and paraffin sections. Paraffin sections were stained according to the streptavidin-biotin complex protocol, and frozen sections according to a two-step immunoperoxidase technique. Aminoethylcarbazole served as the chromogen. The tissues were from normal proliferative endometrium (formalin-fixed paraffin-embedded) material and clear-cell adenocarcinoma of the ovary (formalin-fixed paraffin-embedded and frozen material). Sections were scored for staining in epithelial cells, basal, apical and diffuse cytoplasmic and in stromal components. Intensity was graded as 1, 2 or 3 for epithelial cells and as -1, -2 or -3 for stroma. The cumulative scores for each antibody expressed the discriminative properties of specific epithelial staining against background. M11 and M11-like antibodies, as well as OC125 and OC125-like antibodies, in general showed good staining results. Although there was a trend for high-affinity antibodies to show higher scores, there was no clear relationship between affinity and staining result. For nine antibodies (ZR45, MA602-1, K102, K94, K90, OV185, K97, K96, OV198), the reactions in paraffin and frozen sections were of similar intensity. Most of these were of low affinity with one exception: antibody ZR45, a rat monoclonal antibody (MAb) which had a high relative affinity. For eight antibodies (M11, K101, MA602-6, ZS33, B27.1, B43.13, K93, OC125), a loss of specific staining was observed in frozen sections. All but two of these antibodies (MA602-6 and OC125) were of high relative affinity. With four antibodies (K91, ZR38, K95, K100), the reverse situation was observed. One (K100) was of low affinity, two (K95 and K91) of high affinity and the fourth (ZR38) was a rat MAb of high affinity. Mainly due to the increased cytoplasmic staining in carcinoma, the reactivity in paraffin sections was less extensive in normal endometrium compared to ovarian carcinoma for the majority of antibodies, irrespective of their affinity or epitope group. The IH characterization of these antibodies may be of help in selecting antibodies with specific properties for further comparative studies. The reactivity of normal endometrium with all useful antibodies makes it a good candidate for standard external IH tissue control.

Adenocarcinoma, Clear Cell↗

Internalization of indium-111 into human neuroendocrine tumor cells after incubation with indium-111-DTPA-D-Phe1-octreotide.

UNLABELLED: Neuroendocrine tumor cells frequently overexpress somatostatin receptors at their cell surfaces. To evaluate the possibility of using the somatostatin analog 111In-DTPA-D-Phe1-octreotide for radiation therapy, we studied the binding and subsequent internalization of 111In into three types of cultured human neuroendocrine tumor cells. METHODS: Primary cultures of gastric carcinoid, midgut carcinoid and glucagonoma cells were incubated with 111In-DTPA-D-Phe1-octreotide and cell-surface bound, internalized and released 111In activity was measured. Electron microscopic autoradiography was also performed. RESULTS: All three cell types specifically (80%-95%) bound 111In-DTPA-D-Phe1-octreotide and internalized 111In. After 1 hr pulse incubation with 111In-DTPA-D-Phe1-octreotide, there was an initial decrease in intracellular 111In to about 50% during the subsequent 6-hr incubation. Almost no further release was observed during the remaining 18-42 hr studied. Autoradiography showed that the internalized 111In was found in the cytoplasm and nucleus in the midgut carcinoid cells. CONCLUSION: Indium-111 DTPA-D-Phe1-octreotide might be useful for radiation therapy of patients with surgically incurable tumors having high somatostatin receptor densities.

Autoradiography↗

A developmental switch sufficient for flower initiation in diverse plants.

We have generated transgenic plants in which the flower-meristem-identity gene LEAFY of Arabidopsis is constitutively expressed. LEAFY is sufficient to determine floral fate in lateral shoot meristems of both Arabidopsis and the heterologous species aspen, with the consequence that flower development is induced precociously. Our results also suggest a new level of regulation during flower development, as indicated by the competence of the main shoot to respond to LEAFY activity.

Arabidopsis↗

Are enterochromaffinlike cell tumours reversible? An experimental study on gastric carcinoids induced in Mastomys by histamine2-receptor blockade.

A rapid induction of enterochromaffinlike (ECL) cell tumours has been shown in Praomys (Mastomys) natalensis subjected to histamine2-receptor blockade. In the present study the reversibility of ECL cell proliferation induced by acid inhibition was investigated. Short-term treatment (8 weeks) with the histamine2-receptor antagonist loxtidine caused a moderate hypergastrinemia, accompanied by a minor increase in histamine contents and a 2-fold increased volume density of the endocrine cells in gastric oxyntic mucosa. Eight weeks after withdrawal of treatment the volume density of endocrine cells was normalised as were the tissue levels of histamine, indicating a total reversibility of ECL cell hyperplasia. Long-term treatment (24 weeks) caused severe changes in the endocrine cell population of the oxyntic mucosa with neoplasia (5/21), dysplasia (11/21) and nodular hyperplasia (5/21). The endocrine cell density increased twofold and tissue histamine levels fourfold. 24 weeks after cessation of treatment, the endocrine cell density had decreased to 136% of controls, while histamine concentrations were normalised. The frequency of invasive carcinoids after recovery (4/23) differed only slightly from that seen after treatment for 24 weeks (5/21). Dysplastic lesions were only seen in 1/23 and hyperplastic lesions were of less severe type after recovery. The results demonstrate that ECL cell hyperplasia and dysplasia, induced by acid inhibition, are reversible after cessation of treatment. However, ECL cell tumours did not disappear, within the given observation period. One may therefore speculate that ECL cell proliferation is no longer reversible once the neoplastic (transformed) phenotype has developed.

Animals↗

Expression of transforming growth factor alpha and its receptor in human neuroendocrine tumours.

Transforming growth-factor-alpha (TGF-alpha) is a 50-amino-acid polypeptide that binds to the epidermal growth factor (EGF) receptor and stimulates cell growth. It has been suggested that enhanced production of TGF-alpha and EGF receptors by tumour cells promote tumour-cell growth by autocrine mechanisms. In the present study we have investigated the expression of TGF-alpha and EGF receptors in human neuroendocrine tumours, including midgut carcinoid tumours, phaeochromocytomas and medullary thyroid carcinomas. TGF-alpha expression was demonstrated in biopsies of all tumours examined (n = 30) and EGF receptors in a majority of tumours by Northern analysis and/or immunocytochemistry. Expression of TGF-alpha and EGF receptors was also demonstrated in primary cultures of tumour cells. Carcinoid tumours and phaeochromocytomas in culture secreted detectable amounts of TGF-alpha into the culture medium (400-700 pM). The amount of secreted TGF-alpha could be suppressed by octreotide treatment in individual tumours. Administration of exogenous TGF-alpha stimulated carcinoid tumour growth in vitro as determined by the DNA contents of cell cultures. The growth-stimulatory effect of TGF-alpha could be partially blocked by the use of neutralizing anti-EGF receptor monoclonal antibodies (MAbs). In conclusion, several human neuroendocrine tumours express both TGF-alpha and EGF receptors in in vivo and in vitro, suggesting that TGF-alpha may regulate tumour-cell growth by autocrine mechanisms.

Adrenal Gland Neoplasms↗

Enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to Anoplocephala perfoliata in horse sera.

A scolex antigen of the horse tapeworm Anoplocephala perfoliata containing at least 14 different proteins was employed in an enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to A. perfoliata in equine sera. The assay was applied to sera from 426 slaughtered horses with different numbers of worms and with varying degrees of intestinal lesions. As measured by the ELISA, there was a very strong effect on the antibody levels both from the number of tapeworms present and from the intestinal lesion score. However, considerable individual variation was observed between horses with similar worm counts. The ELISA values of horses that were either negative for strongyles and tapeworms or positive only for strongyles were similar, whereas both of these groups differed significantly from animals that harboured only A. perfoliata. Thus it seemed that cross-reactivity with concurrent nematode infections did not occur. Furthermore, a significant seasonal pattern in antibody levels was observed which reflected the establishment of newly acquired infections. No observations were made of confounding effects owing to age and previous anthelmintic treatment of the horses. It is concluded that the ELISA presented here has a potential for monitoring A. perfoliata infection on a herd level and can be used as a complementary diagnostic tool in epidemiological studies. The present study indicates that transmission of A. perfoliata in Central Sweden occurred during a short period in spring and more consistently in late autumn.

Aging↗

Accumulation of natural killer cells after hepatic artery embolisation in the midgut carcinoid syndrome.

Eleven patients with disseminated midgut carcinoid tumour disease were subjected to hepatic artery embolisation. In six patients, lymphocytosis with a predominance of NK cells occurred and the cytotoxic activity of isolated lymphocytes increased. A relation between NK cell accumulation and subsequent radiological and biochemical response was observed, and it is suggested that anti-tumour mechanisms other than ischaemia may contribute to the therapeutic response in these patients.

Cytotoxicity, Immunologic↗

Protein-losing enteropathy in an unusual form of sarcoidosis.

We describe a case of sarcoidosis associated with great gastrointestinal loss of proteins. It was hypothesized that the loss was caused by involvement of sarcoidosis in the gastrointestinal tract. The patient was a 39-year-old woman with sarcoidosis diagnosed at age 32 years. The protein-losing enteropathy was identified by the use of [51Cr]-albumin. An extensive investigation was performed, with biopsy specimens taken from all parts of the gastrointestinal tract, using upper gastrointestinal endoscopy, colonoscopy and the Crosby capsule technique. We could find no support for our hypothesis that the leakage of proteins was caused by involvement of sarcoidosis in the gastrointestinal tract. Thus, mechanisms other than direct inflammatory involvement of the gastrointestinal mucosa probably caused protein-losing enteropathy in this patient.

Adult↗