Biomedical subjects

J Bojunga

Publications and source records attributed to J Bojunga.

13 recordsLinked to original sources

PubMed2004

Antioxidative treatment prevents activation of death-receptor- and mitochondrion-dependent apoptosis in the hearts of diabetic rats.

AIMS/HYPOTHESIS: The mechanisms by which glucose injures cells of the cardiovascular system include generation of reactive oxygen species and induction of cellular apoptosis. To date, little is known about the molecular events of hyperglycaemia-induced apoptosis in the heart in vivo. METHODS: Male Sprague-Dawley rats were rendered diabetic by a single intraperitoneal injection of 60 mg/kg body weight streptozotocin. Caspase activities in cardiac ventricular tissue were determined using fluorometric and immunoassay caspase-activity assay kits respectively. Expression levels of proteins of the apoptotic cascade were determined with western blot analyses using specific antibodies. RESULTS: Four weeks of hyperglycaemia induced significant apoptosis in cardiac tissue. Determining the initiators of death-receptor-dependent apoptosis revealed induction of CD95/Fas and caspase-8. Examination of the activities of effector caspases revealed increased activity of caspase-6, but not caspase-3 and -7. On evaluating inhibitors of apoptosis, we found up-regulation of caspase-3 and -7-inhibiting X-linked inhibitors of apoptosis in diabetic rats. Hyperglycaemia also induced significant mitochondrion-dependent apoptosis. Our evaluation of expression levels of Bcl-2 family members showed increased expression of pro-apoptotic Bak and Bax in diabetic rats. Antioxidative treatment with lipoic acid significantly suppressed apoptosis and down-regulated caspase-6, -8 and -9 activity, as well as expression levels of pro-apoptotic Bcl-2 proteins without changing blood glucose levels. CONCLUSIONS/INTERPRETATION: The present study indicates that reactive oxygen species induced by high glucose are involved in both death-receptor- and mitochondrion-dependent apoptosis in the heart in vivo. It also suggests that antioxidants may be a therapeutic option for preventing cardiovascular damage in diabetes mellitus in humans.

Animals↗

PubMed2002

Differences in tumor cell proliferation, HLA DR expression and lymphocytic infiltration in various types of thyroid carcinoma.

The proliferative activity of various thyroid carcinoma forms (papillary, follicular, medullary, anaplastic) was investigated using two second generation antibodies against Ki-67 that can be used on paraffin-embedded sections. Poorly-differentiated carcinomas had a higher proliferation than well-differentiated forms. Papillary carcinoma stained significantly more often with either antibody than follicular carcinoma. A solid growth pattern correlated with high Ki-67 expression while an increase in follicular elements and a high amount of psammoma bodies coincided with lower proliferation.HLA class II expression and infiltrating lymphocytes are prerequisites for an immune defense against cancer. In this study, HLA DR was increased in poorly-differentiated carcinomas, especially in the anaplastic type. The increase in HLA DR was correlated with Ki-67 positivity. On tumor-infiltrating lymphocytes, HLA DR was well expressed in papillary carcinoma and relatively poorly expressed in follicular carcinoma, but there was no significant correlation with carcinoma type or morphological parameters. CD 45 R0, which might recognize memory cells, was found mostly in anaplastic and papillary carcinomas, and correlated well with HLA DR expression. These findings imply that an active but variable immune response is present in thyroid carcinoma.

Adolescent↗

PubMed2002

Detection of thyroid peroxidase mRNA in peripheral blood of patients with malignant and benign thyroid diseases.

The aim of this study was to evaluate thyroid peroxidase (TPO) mRNA expression in peripheral blood of patients with benign and malignant thyroid disease. Included were 120 thyroid cancer patients, 85 patients with goitre or Graves' disease (GD) and 54 healthy volunteers. TPO mRNA expression was analysed in peripheral blood by nested RT-PCR. In cancer patients, RT-PCR results were compared with staging, grading and serum thyroglobulin (TG) measurement. TPO transcripts were detected in 7/10 (70%) patients with known metastases of thyroid cancer and in 39 of 110 (36%) patients without metastases (P<0.05), in 15/44 (34%) patients with goitre, in 17/41 (41%) cases with GD and in 4/54 (7.4%) subjects in the control group (P<0.05, controls vs all patients with thyroid disease). Among cancer patients without metastatic disease, RT-PCR results correlated positively with lymph node status (P=0.05), grading (P=0.01) and elevated serum thyroglobulin levels (P=0.03). This is the largest study investigating the use of the TPO-RT-PCR assay. Positivity in TPO-RT-PCR correlates significantly with metastatic disease in cancer patients and with the presence of thyroid disease in general. To date, TPO-RT-PCR cannot substitute for standard techniques in the diagnosis of local recurrence or metastatic spread in thyroid cancer patients. However, as results of TPO-RT-PCR correlate significantly with lymph node status, grading and serum TG measurements in patients with non-metastatic disease, TPO seems to be an interesting molecular marker to look at in follow-up studies.

Adult↗

PubMed2001

Circulating calcitonin and carcinoembryonic antigen m-RNA detected by RT-PCR as tumour markers in medullary thyroid carcinoma.

Detection of local relapse or metastasis in medullary thyroid carcinoma (MTC) continue to pose a major diagnostic challenge. Besides established diagnostic studies such as serum calcitonin (CT) and carcinoembryonic antigen (CEA), molecular detection of circulating tumour cells may be an additional diagnostic tool for the early detection of disease recurrence. We performed reverse transcription-polymerase chain reaction (RT-PCR) on blood samples from patients diagnosed with MTC disease using primers specific for CT and CEA, respectively. CT mRNA was not detectable in peripheral blood of all patients with MTC (n = 11) and all controls (n = 32). CEA mRNA was significantly more often detected patients with MTC (72.7%) than in controls (34.4%; p = 0.038; Fisher exact test). With an example of a patient with MTC and massive tumour mass in the neck we demonstrate the failure of detection of CT mRNA over a period of 6 months, whereas CEA mRNA could be detected in peripheral blood of this patient. As a consequence, CT mRNA detected by RT-PCR in the peripheral blood can not be recommended as a tumour marker in MTC. However, the use of carcinoembryonic mRNA may provide a significant improvement in diagnosis of recurrent disease in MTC.

Biomarkers, Tumor↗

PubMed2000

Molecular detection of thyroglobulin mRNA transcripts in peripheral blood of patients with thyroid disease by RT-PCR.

The sensitive detection of circulating tumour cells in patients with differentiated thyroid cancer may precede the detection of relapse by other diagnostic studies--such as serum thyroglobulin-and thus may have important therapeutic and prognostic implications. We performed reverse transcription-polymerase chain reaction (RT-PCR) on blood samples from patients diagnosed with thyroid disease using two different RT-PCR sensitivities. Additionally, tissue specificity of TG mRNA-expression was determined using RNA extracts from 27 different human tissues. The lower limit of detection was 50-100 TG mRNA producing cells/ml blood using a 'normal' RT-PCR sensitivity and 10-20 cells/ml blood using a 'high' sensitivity. With the normal sensitivity TG mRNA was detected in 9/13 patients with thyroid cancer and metastasis, 63/137 patients with a history of thyroid cancer and no metastasis, 21/85 with non-malignant thyroid disease and 9/50 controls. With the high sensitivity TG mRNA was detected in 11/13 patients with thyroid cancer and metastasis, 111/137 patients with a history of thyroid cancer and no metastasis, 61/85 with non-malignant thyroid disease and 41/50 controls. Interestingly, using the normal RT-PCR sensitivity TG mRNA transcripts are specific for thyroid tissue and detectable in the peripheral blood of controls and patients with thyroid disease, which correlates with a diagnosis of metastasized thyroid cancer. However, with a high RT-PCR sensitivity, TG mRNA expression was found not to be specific for thyroid tissue and was not correlated with a diagnosis of thyroid cancer in patients. As a consequence, to date TG mRNA detected by RT-PCR in the peripheral blood cannot be recommended as a tumour marker superior to TG serum-level.

Case-Control Studies↗

PubMed1999

Historical evolution of limb amputation.

The amputation of a limb is one of the oldest surgical procedures. In the course of medical history operative techniques and surgical instruments have been improved continuously. As early as the first century Celsus described an amputation. A major step in the development of the operative technique was the introduction of an artery forceps by Paré during the sixteenth century. Nevertheless, due to a lack of analgesics and narcotics the operation had to take only a few minutes. Therefore the amputation was completed in one cut (i.e., detachment of the skin, muscles, and bone at the same level). This technique, known as "classic circular cut," was modified several times in the following period: to reduce suture tension Petit recommended that we transect the skin first and the muscles and bone more proximally ("two-stage circular cut," 1718), and Bromfield approved that the skin be cut first, the muscles more proximally and the bone most proximal ("three-stage circular cut," 1773). Lowdham (1679), Verduyn (1696), and Langenbeck (1810) changed the operative technique in that they used a soft-tissue flap to cover the bone without tension ("flap amputation").

Amputation, Surgical↗

PubMed1999

In vivo microscopy of murine islets of Langerhans: increased adhesion of transferred lymphocytes to islets depends on macrophage-derived cytokines in a model of organ-specific insulitis.

Environmental factors contribute to the pathogenesis of type 1 diabetes (insulin-dependent diabetes mellitus). Multiple low doses of streptozotocin (MLDS) induce hyperglycaemia and insulitis in mice. Previously we demonstrated that adhesion of lymphocytes to endothelium of islets is only increased when donor animals were diabetic and recipient mice had received 5 mg/kg streptozotocin (STZ). Therefore we used streptozotocin to evaluate the immunological relevance of such an irritation of islets. Lymphocytes, separated from diabetic mice (MLDS), were fluorescently labelled and injected to recipient mice that had received 5 mg/kg STZ. With in vivo microscopy we measured lymphocyte flow and adherence in islets. Expression of vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 (ICAM-1) in the pancreas was assessed using immunohistochemistry. Very late antigen-4 (VLA-4) and leucocyte function-associated antigen-1 (LFA-1) expression on transferred lymphocytes was measured with flow cytometry. Pretreatment of recipients with antibodies to cytokines or silica reduced lymphocyte adherence to islet endothelium from 2.04% (goat immunoglobulin G; IgG) or 1.82% (rat IgG) to 0.47, 0.58, 0.39 or 0. 19% for monoclonal antibody (mAb) interferon-gamma (IFN-gamma), polyclonal antibody (pAb) tumour necrosis factor-alpha (TNF-alpha), pAb interleukin (IL)-1alpha or silica, respectively. Reduced adhesion was associated with a decreased expression of VCAM-1 and ICAM-1 in islets of treated recipients compared with mice treated with 5 mg/kg STZ alone. In conclusion, pretreatment of recipients with 5 mg/kg STZ leads to an increased expression of adhesion molecules in the islets and lymphocyte adhesion to islet endothelium in vivo, demonstrating an immune response of the islets. Prevention of increased expression of ICAM-1 or VCAM-1 and reduction of lymphocyte adhesion in islets by silica or antibody indicate an involvement of macrophages and macrophage derived cytokines in the generation of this immune response.

Animals↗

PubMed1999

Macrophage and lymphocyte homing in experimental diabetes.

Diabetes mellitus was induced in C57BL/6 mice by multiple low doses of streptozotozin (STZ). By transferring lymphocytes from these diabetic animals to healthy recipient mice insulitis can be induced in healthy recipient mice. On day 21 after the start of STZ-treatment splenic lymphocytes were separated in vitro and stained with the fluorochrom acridine red for adoptive transfer. The recipient mouse had been pretreated with a subdiabetogenic dose of STZ (5 mg/kg) i.p. 24 h prior to the lymphocyte transfer. With in vivo microscopy we measured the lymphocyte adherence to the endothelium of islets of the recipient mouse. After the administration of mAbs directed against LFA-1, ICAM-1, murine VCAM-1, VLA-4, MadCAM or alpha4,beta7-integrin prior to the cell transfer we could demonstrate a significant decrease of donor lymphocyte adherence in islets (P<0.01). The pretreatment of the recipient mice with STZ 24 h before the transfer of lymphocytes might attract macrophages to the islets. Therefore we pretreated the recipients with antibodies to cytokines or silica. mAb IFN-gamma, pAb TNF-alpha, pAb IL-1alpha or silica reduced lymphocyte adherence to islet endothelium significantly (P<0.01). The presented results support the following interpretation: The pretreatment of the recipient mice with the islet specific toxin STZ in subdiabetogenic doses attracts macrophages to the islets. The macrophages release cytokines leading to an increased expression of adhesion molecules on the endothelium of the islets. The consequence is lymphocyte homing selectively to the islets. The cascade of lymphocyte homing is complex and various pairs of adhesion molecules are involved. The discussion on the importance of the single pairs of adhesion molecules is irrelevant, since the cascade of lymphocyte homing can be disturbed by the application of a mAb to any one adhesion molecule involved in the cascade of lymphocyte homing.

Animals↗

PubMed1998

Lymphocyte transfer in streptozotocin-induced diabetes: adhesion of donor cells to islet endothelium.

The interaction between intravenously transferred lymphocytes derived from spleens of multiple low-dose streptozotocin-diabetic mice with islet, exocrine pancreatic, and gastric mucosal endothelium of nondiabetic recipient mice was investigated by in vivo microscopy. Donor lymphocytes were stained with acridine red in vitro. The adoptive transfer of these cells from diabetic donor animals resulted in significantly increased lymphocyte rolling (4.46 +/- 1.32%, P < 0.05) and adhesion (3.86 +/- 1.04%, P < 0.05) in islets of nondiabetic recipients that had been pretreated with a single subdiabetogenic dose of streptozotocin. No increased endothelial interaction was noted in nonpretreated recipients or in experiments with nondiabetic donors. Rolling (1.19 +/- 0.61 to 2.71 +/- 0.62%) and adhesion (0.61 +/- 0.33 to 2.80 +/- 0.97%) of donor lymphocytes were low in exocrine pancreatic and gastric mucosal control tissue. It is concluded that, in this animal model, lymphocytes from diabetic donors interact preferentially with recipient islet endothelium. However, additional stimulation of recipient islet endothelium by exogenous factors is necessary to enable transferred cells to adhere to pancreatic islets.

Animals↗

PubMed1998

Soluble ICAM-1 reduces leukocyte adhesion to vascular endothelium in ischemia-reperfusion injury in mice.

Ischemia-reperfusion injury is a pathogenic factor in the course of many clinical disorders, such as myocardial infarction, stroke, organ transplantation, burns, and circulatory shock. The extent of ischemia-reperfusion injury is dependent on the number of infiltrating leukocytes. With in vivo microscopy, we evaluated the effect of the recombinant form of soluble murine intercellular adhesion molecule-1 (ICAM-1) on ischemia-reperfusion injury in an animal model. A mesenteric vein was occluded with a clamp for 45 min. During a reperfusion period of 30 min, the number of leukocytes rolling along the endothelium and the number of adherent leukocytes were measured with and without pretreatment with recombinant ICAM-1. The number of leukocytes rolling along the endothelial surface increased more than twofold during postischemic perfusion (P < 0.05). Recombinant ICAM-1 had no effect on leukocyte rolling. In the control group, firm adherence of leukocytes was increased 10-fold. Recombinant ICAM-1 dose dependently reduced firm adhesion to the endothelium in response to prior ischemia. After 30 min, reperfusion pretreatment with recombinant ICAM-1 inhibited leukocyte adherence from 512 +/- 123 to 166 +/- 34 leukocytes/mm2 (P < 0.01). We demonstrate here for the first time that soluble recombinant ICAM-1 is able to reduce leukocyte adherence to mesenteric venules in postischemic reperfusion injury dose dependently. Because soluble ICAM-1 is naturally circulating in human serum, the therapeutic use of soluble recombinant forms of ICAM-1 may represent a physiological way to protect against ischemiareperfusion injury.

Analysis of Variance↗

PubMed1998

[The so-called Spigelian hernia--a rare lateral hernia of the abdominal wall].

A patient with Spigelian hernia is presented and the main pathological and clinical features are discussed. Its true incidence is probably greater than the small number of patients reported in the literature due to failure to recognize the clinical picture. A hernia through a defect in the Spigelian fascia (aponeurosis of the transverse muscle of the abdomen) is called Spigelian hernia. The semilunar (Spigelian) line is defined as the line forming the transition from muscle to aponeurosis in the transverse muscle of the abdominal wall. It is a lateral convey line between the costal arch and the pubic tubercle. The part of the aponeurosis that lies between this semilunar line and the lateral edge of the rectus muscle is called the "Spigelian fascia" (correct: Spigelian aponeurosis). The hernia is located intramurally because the hernia is covered by the aponeurosis of the external oblique aponeurosis, so that both, the hernial sac and the orifice, can often not be detected by palpation. Clinical symptoms are not characteristic but most patients have a distinct tender point above the hernial orifice.

Abdominal Muscles↗

PubMed1998

[History of surgical instruments: 8. Instruments and development of amputation technique exemplified by amputation sets from the middle of the 19th century].

The amputation of a limb is one of the oldest surgical procedures. However, in the course of medical history operative techniques and surgical instruments have been improved continuously. With an example of an amputation case of the last century we will summarize this development until the middle of the nineteenth century. Even in the first century Celsus gave a description of an amputation (circular cut). A major step in the development of the operative technique was the introduction of artery forceps by A. Paré in the sixteenth century. Nevertheless, due to a lack of analgesics and narcotics the operation had to take only a few minutes. Therefore the amputation was completed in one cut, i.e. detachment of the skin, muscles and bone at the same level. This technique known as "classic circular cut" was modified several times in the following period: in order to reduce suture tension Petit recommended to transect the skin first and the muscles and bone more proximal ("two-stage circular cut", 1718) and Bromfield approved to cut in turn the skin first, the muscles more proximal and the bone most proximal ("three-stage circular cut", 1773). Finally, Lowdham (1679), Verduyn (1696) and C. J. M. Langenbeck (1810) changed the operative technique to the effect that they used a soft-tissue flap in order to cover the bone without tension ("flap amputation").

Amputation, Surgical↗

PubMed1995

Intravital measurement of donor lymphocyte adhesion to islet endothelium of recipient animals in diabetes transfer experiments.

An in vivo microscopic technique is described that was developed to measure the interaction between transferred donor lymphocytes and islet endothelium in diabetes transfer experiments. With double fluorescent tracer staining by acridine red and FITC-dextran the simultaneous assessment of lymphocyte adhesion and shear forces acting upon adherent cells was possible. Staining the isolated donor lymphocytes with acridine red did not significantly affect their viability. Proliferation capability was maintained after the staining procedure. By using exocrine pancreatic tissue as a reference vascular bed, the specificity of the observed changes in lymphocyte adherence in pancreatic islets could be demonstrated. This new approach in microcirculatory research will help to clarify the mechanisms underlying the initial steps of lymphocyte infiltration into islet tissue in autoimmune diabetes mellitus.

Animals↗