Experimentelle Forschung an der Klinik und Poliklinik für Dermatologie und Venerologie

Seit Antritt von Prof. Dr. med. Steffen Emmert als Ordinarius der Klinik und Poliklinik für Dermatologie und Venerologie im Jahr 2015 konnte das dermatologische Forschungslabor sukzessive aufgebaut und erweitert werden. Im Einklang mit dem onkologischen Schwerpunkt der Universitätsmedizin Rostock sowie dem von der Landesregierung forcierten „Gesundheitsland Mecklenburg-Vorpommern“ wird grundlagenorientierten und translationalen Projekten nachgegangen. Das vorwiegend drittmittelfinanzierte und stetig wachsende Forschungsteam bearbeitet diverse Fragestellungen in den Bereichen der Dermato-Onkologie, Plasmamedizin und seltenen Hauterkrankungen. Inzwischen auf einem soliden Fundament stehend, befindet sich der Forschungsbereich weiterhin in einem dynamischen Entwicklungsprozess. Nicht nur personell, sondern auch thematisch und methodisch wird er derzeit durch die Integration weiterer Arbeitsgruppen unter der Leitung von Ärzten aus der Klinik ergänzt und ausgebaut. Diverse Kollaborationen an der Universitätsmedizin Rostock und im Land zeugen von einem freundlichen, unterstützenden und kollegialen Umfeld, das die Integration am Standort befördert hat.

[Changing spectrum of renal disease in HIV infection]

BACKGROUND AND OBJECTIVE

Renal disease is a common complication in HIV-infected patients. The causes and spectrum of kidney disease among these patients is extensive, including HIV-related and HIV unrelated causes. Our objective was to assess the changes in distribution of renal disease under antiretroviral therapy (ART).

PATIENTS AND METHODS

Retrospective analysis of all patients from the Frankfurt HIV Cohort (FHC) who underwent renal biopsy because of chronic, progressive renal disease between 1989 and 2012. Two time periods were defined: 1989-2001 (early period) and 2000-2012 (late period).

RESULTS

69 HIV-infected patients, mostly Caucasian and male, underwent renal biopsy (early period: 22 patients, late period: 47 patients). During the total observation time immuncomplex-mediated glomerulonephritis (26.1 %), hypertensive (20.3 %) and diabetic nephropathy (20.3 %) were the most frequent causes of chronic renal disease. HIV-associated renal diseases were predominant in the first period, whereas hypertensive and diabetic kidney disease accounted for almost 50 % of cases diagnosed in the late period. Other types of renal disease frequently encountered during the late period include renal AA-amyloidosis and tenofovir-related kidney disease.

CONCLUSION

The underlying pathology of renal disease in HIV-infected patients is highly variable and evolving. Since the introduction of HAART, renal disease not directly related to HIV has become the predominant cause, reflecting the growing burden of co-morbidities in this aging population.

Acute kidney injury caused by tenofovir disoproxil fumarate and diclofenac co-administration

OBJECTIVES

The renal elimination of tenofovir (TFV) may be subject to renal drug-drug interactions that may increase the risk of kidney injury. Case reports indicated that diclofenac might increase TFV-associated nephrotoxicity via a drug-drug interaction, leading to an increased intracellular TFV concentration in proximal tubular cells.

METHODS

A retrospective analysis of data for all patients from the Frankfurt HIV Cohort (FHC) who had diclofenac prescriptions between January 2008 and June 2012 was carried out.

RESULTS

Among 89 patients with diclofenac use, 61 patients (68.5%) were treated with tenofovir disoproxil fumarate (TDF) and 28 patients (31.5%) were treated with TDF-sparing combination antiretroviral therapy (cART). Thirteen patients (14.6%) developed acute kidney injury (AKI) shortly after initiating diclofenac treatment. AKI occurred exclusively in TDF-treated patients, although all had previously stable renal function. All cases were accompanied by new onset of at least two parameters indicating proximal tubular damage, such as normoglycaemic-glucosuria and hypophosphataemia. TFV-associated nephrotoxicity was demonstrated by renal biopsy in four cases. Additionally, 11.5% of patients on TDF treatment developed new-onset proximal tubular damage, while having a preserved glomerular filtration rate. In contrast, diclofenac did not affect renal function in patients with TDF-sparing cART, as only one case of isolated hypophataemia was observed in these patients. In univariate analysis, risk factors for AKI were TDF-containing cART (P = 0.0076) and pre-existing hypophosphataemia (P = 0.0086).

CONCLUSIONS

Drug-drug interaction caused by diclofenac could exacerbate TFV-associated nephrotoxicity. Diclofenac should be used with caution in patients on TDF therapy, especially in those with hypophosphataemia. Our findings need to be confirmed in larger studies.

[Appraisal, diagnosis and therapy of chronic metabolic acidosis in Germany]

BACKGROUND AND OBJECTIVE

Data concerning chronic metabolic acidosis (CMA) has been sparse for a long time. This might be one reason why the diagnosis and therapy of this common complication in CKD patients has not received much attention. Emerging clinical data indicate that the treatment of metabolic acidosis, which is simple and cost-efficient, offers great therapeutic potential.

PATIENTS AND METHODS

Survey among German nephrologists to collect information about current appraisal, diagnostic and therapeutic routine in clinical practice, and to determine the need for recommendations by the medical society.

RESULTS

In August 2012, all nephrologists in Germany (n = 2095) were asked to complete a standardized questionnaire regarding diagnosis, evaluation and therapy of CMA. 207 questionnaires (9.9 %) were returned and analysed. The CMA was rated as the second most important contributor for the progression of renal insufficiency, with the most important being hypertension. In addition, there was a high consensus concerning diagnosis and therapy of CMA. But estimates on prevalence were highly diverse.

CONCLUSION

In this survey the CMA was rated as an important co-morbidity. Participating nephrologists mostly followed treatment guidelines. However, major differences in the perception of prevalence of CMA were observed, leaving the possibility that CMA is still underdiagnosed. Further recommendations of the German Society of Nephrology could improve the diagnosis and therapy.

[Breast cancer centres in North Rhine-Westphalia - case volume trends 2004-2010]

BACKGROUND

To improve quality of breast cancer care, in 2004 the state of North Rhine-Westphalia (NRW), Germany, began to appoint 51 breast cancer centres. These centres comprise 91 hospitals performing breast cancer surgery which have - amongst other things - to fulfill minimum volume standards. The aim of our study was to analyse if the intended regionalisation of care from 252 hospitals performing breast cancer surgery formerly to the appointed hospitals had taken place by the year 2010.

METHODS

We used data for the years 2004-2010 from the agency for quality assurance in North Rhine-Westphalia concerning breast cancer care and analysed trends concerning the number of hospitals performing breast cancer surgery, case volumes, and achievement of minimum volume standards by performing descriptive and inferential statistics.

RESULTS

Between 2004 and 2010 the number of breast cancer cases increased by 36.6% from 12 975 to 17 724 cases (p<0.001, Wilcoxon test). Simultaneously, the number of hospitals performing breast cancer surgery decreased from 252 to 208 whereby more than double the number of planned hospitals still performed breast cancer surgery. The case volumes of the 71 appointed hospitals for which we had individual data over the entire period of time increased by 49.4% from 8 103 cases in year 2004 to 12 105 cases in 2010. Assuming that case volume trends of those 20 appointed hospitals of which we did not have individual data developed uniformly to all other appointed hospitals, the proportion of cases that were operated in not appointed hospitals decreased from 20% in year 2004 to 12.5% in 2010 (p<0.001, χ2 test). Simultaneously, the proportion of cases that were operated in hospitals not achieving minimum volume standards decreased from 42.7% in year 2004 to 12.1% in 2010 (p<0.001, χ2 test).

CONCLUSION

The establishment of breast cancer centres in NRW regionalised breast cancer surgery. In fact, in 2010 breast cancer surgery still took place in more than 100 not appointed hospitals. However, these hospitals were responsible for only a small proportion of breast cancer surgery.

End-stage renal disease and dialysis in HIV-positive patients: observations from a long-term cohort study with a follow-up of 22 years

OBJECTIVES

Renal disease is a common and serious complication in HIV-infected patients.

METHODS

A retrospective cohort analysis for the period 1989-2010 was carried out to determine the prevalence, incidence and risk factors for end-stage renal disease (ESRD). ESRD was defined as initiation of renal replacement therapy. Three time periods were defined: 1989-1996 [pre-highly active antiretroviral therapy (HAART)], 1997-2003 (early HAART) and 2004-2010 (late HAART).

RESULTS

Data for 9198 patients [78.2% male; 88.9% Caucasian; cumulative observation time 68 084 patient-years (PY)] were analysed. ESRD was newly diagnosed in 35 patients (0.38%). Risk factors for ESRD were Black ethnicity [relative risk (RR) 5.1; 95% confidence interval (CI) 2.3-10.3; P < 0.0001], injecting drug use (IDU) (RR 2.3; 95% CI 1.1-4.6; P = 0.02) and hepatitis C virus (HCV) coinfection (RR 2.2; 95% CI 1.1-4.2; P = 0.03). The incidence of ESRD decreased in Black patients over the three time periods [from 788.8 to 130.5 and 164.1 per 100 000 PY of follow-up (PYFU), respectively], but increased in Caucasian patients (from 29.9 to 41.0 and 43.4 per 100 000 PYFU, respectively). The prevalence of ESRD increased over time and reached 1.9 per 1000 patients in 2010. Mortality for patients with ESRD decreased nonsignificantly from period 1 to 2 (RR 0.72; P = 0.52), but significantly from period 1 to 3 (RR 0.24; P = 0.006), whereas for patients without ESRD mortality decreased significantly for all comparisons. ESRD was associated with a high overall mortality (RR 9.9; 95% CI 6.3-14.5; P < 0.0001).

CONCLUSION

As a result of longer survival, the prevalence of ESRD is increasing but remains associated with a high mortality. The incidence of ESRD declined in Black but not in Caucasian patients. IDU and HCV were identified as additional risk factors for the development of ESRD.

Pathologic alterations of the heart and the kidney in patients with ankylosing spondylitis

BACKGROUND

The occurrence of a variety of pathological lesions of the heart and kidneys have been described in patients with ankylosing spondylitis (AS). The frequency of these alterations and whether they are specific for AS has been discussed controversially. -

METHODS

Outpatients with AS were studied to determine the frequency of cardiac and renal alterations and to assess the associated clinical and demographic factors. -

RESULTS

A total of 77 patients with AS participated in the study (male 84.4%, mean age 48.3 +/- 1.5 years, mean duration of disease 15.4 +/- 1.2 years). Hypertension was present in 36.4% and diabetes mellitus in 13.0%. Impaired renal function (defined by a decrease in GFR) combined with markers of kidney damage suspective for chronic kidney disease were present in 3 patients (3.9%). Pathologic alterations of the heart were found in 25 patients (37.3%). Echocardiographic abnormalities were present in 20 patients (e.g. aortic and mitral insufficiency). Electrocardiographic abnormalities were present in 12 patients (e.g. atrioventricular, left and right branch block). Patients with cardiac abnormalities were older (54.2 +/- 2.9 vs. 44.9 +/- 1.7 years) and had a longer duration of disease (20.6 +/- 2.1 vs. 13.9 +/- 1.6 years) as compared to non-affected patients. -

CONCLUSION

In our study, cardiac abnormalities were frequently seen in patients with AS, while renal disease was more rare and might be due to diseases not related to AS in most of patients. In contrast to cardiac involvement, it therefore appears questionable, that chronic kidney disease is part of the extraskeletal manifestations, or at least that AS has a high impact on renal integrity.

Long-term therapy of acute chronic liver failure to successful transplantation with an extracorporeal liver support system

We report the case of a 38-year-old Caucasian male who was admitted because of end-stage liver failure due to primary sclerosing cholangitis. Because of the rapidly progressive severe hepatic encephalopathy and development of hepatorenal syndrome type I, the patient was immediately upgraded to a high priority status on the liver transplantation waiting list (T2 status according to Eurotransplant criteria). Intermittent therapy with an extracorporeal liver support system (Prometheus) was initiated in order to bridge the time period until the expected transplantation date. Under therapy with the extracorporeal liver support system, total serum bilirubin decreased significantly from 33 to 15 mg/dL after 8 sessions. Simultaneously the encephalopathy resolved gradually within 3 weeks (10 sessions) from initially grade 3 to grade 1. Extracorporeal detoxification therapy was continued for 51 days (23 sessions) until the patient underwent his successful liver transplantation in good general clinical condition. Prometheus, a new liver support system, seemed to sufficiently replace hepatic detoxification on a long-term basis in this patient with end-stage liver failure in order to bridge the time period until liver transplantation.

gp91phox-Containing NADPH Oxidase Mediates Endothelial Dysfunction in Renovascular Hypertension

Background— Isoforms of the NADPH oxidase contribute to vascular superoxide anion ( · O 2 − ) formation and limit NO bioavailability. We hypothesized that the endothelial gp91phox-containing NADPH oxidase is predominant in generating the O 2 − to scavenge endothelial NO and thus is responsible for the development of endothelial dysfunction.

Methods and Results— Endothelial dysfunction was studied in aortic rings from wild-type (WT) and gp91phox-knockout (gp91phox −/− ) mice with and without renovascular hypertension induced by renal artery clipping (2K1C). Hypertension induced by 2K1C was more severe in WT than in gp91phox −/− mice (158±2 versus 149±2 mm Hg; P <0.05). Endothelium-dependent relaxation to acetylcholine (ACh) was attenuated in rings from clipped WT but not from clipped gp91phox −/− mice. The reactive oxygen species (ROS) scavenger Tiron, PEG-superoxide dismutase, and the NADPH oxidase inhibitory peptide gp91ds-tat enhanced ACh-induced relaxation in aortae of clipped WT mice. Inhibition of protein kinase C, Rac, and the epidermal growth factor receptor kinase, elements involved in the activation of the NADPH oxidase, restored normal endothelium-dependent relaxation in vessels from clipped WT mice but had no effect on relaxations in those from gp91phox −/− mice. Relaxations to exogenous NO were attenuated in vessels from clipped WT but not clipped gp91phox −/− mice. After removal of the endothelium or treatment with PEG-superoxide dismutase, NO-induced relaxations were identical in vessels from clipped and sham-operated WT and gp91phox mice.

Conclusions— These data indicate that the formation of O 2 − by the endothelial gp91phox-containing NADPH oxidase accounts for the reduced NO bioavailability in the 2K1C model and contributes to the development of renovascular hypertension and endothelial dysfunction.

Study of Nd3+, Pd2+, Pt4+, and Fe3+ dopant effect on photoreactivity of TiO2 nanoparticles

The metallorganic chemical vapor deposition method was successfully used to synthesize pure TiO(2) and Nd(3+)-, Pd(2+)-, Pt(4+)-, and Fe(3+)-doped TiO(2) nanoparticles. Polycrystalline TiO(2) structure was verified with x-ray diffraction, which showed typical characteristic anatase reflections without any separate dopant-related peaks. Transmission electron microscopy observations confirmed the existence of homogeneously distributed 22 +/- 3 nm TiO(2) nanoparticles. The particle size remained the same for the doped samples. The doping level of transition metals was kept at approximately 1 atomic percent, which was determined by x-ray photoelectron spectra and energy dispersive x-ray spectroscopy. The effects of different types of dopants on the photocatalytic activity were revealed by the degradation of 2-chlorophenols with an UV light source. The photocatalytic efficiency was remarkably enhanced by the introduction of Pd(2+) and Nd(3+). Nd(3+)-doped TiO(2) showed the largest enhancement. However, Pt(4+) changed the 2-chlorophenol degradation rate only slightly, and Fe(3+) was detrimental to this process. These effects were related to the position of the dopants in the nanoparticles and the difference in their ionic radii with respect to that of Ti(4+).

Relationship between disease activity and serum levels of vitamin D metabolites and parathyroid hormone in ankylosing spondylitis

Vertebral fractures due to osteoporosis are a common but frequently unrecognized complication of ankylosing spondylitis (AS) and various factors may contribute to the development of osteoporosis in AS. It is known that inflammatory activity in rheumatic disease (i.e., proinflammatory cytokines) itself plays a possible role in the pathophysiology of bone loss. 1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) seems to be another possible candidate for mediatory function in regulating both the inflammatory process and bone turnover. The aim of this study was to evaluate the relation between disease activity, bone turnover and calciotropic hormones. In 70 patients with established AS and an age- and sex-matched control group, the relation between disease activity (erythrocyte sedimentation rate, C-reactive protein, Bath Ankylosing Spondylitis Disease Activity Index), and serum levels of vitamin D metabolites, parathyroid hormone (PTH), bone alkaline phosphatase (bAP) and urinary pyridinium cross-links were determined. Serum levels of 1,25(OH)2D3 (p<0.01) and PTH (p<0.01) were negatively correlated with disease activity, the excretion of urinary pyridinium crosslinks showed a positive correlation with disease activity (p<0.01), and 1,25(OH)2D3 and PTH were positively correlated with bAP (p<0.01). These results indicate that high disease activity in AS is associated with an alteration in vitamin D metabolism and increased bone resorption. Furthermore, the decreased levels of 1,25(OH)2D3 may contribute to a negative calcium balance and inhibition of bone formation. Our results suggest further research is necessary to determine whether low levels of 1,25(OH)2D3 as an endogenous immune modulator suppressing activated T cells and cell proliferation may accelerate the inflammation process in AS.

The K(ATP) channel blocker HMR 1883 does not abolish the benefit of ischemic preconditioning on myocardial infarct mass in anesthetized rabbits

Previous experimental studies showed that the benefit of ischemic preconditioning (IPC) is abolished by K(ATP) channel blockade with glibenclamide. However, the newly discovered K(ATP) channel blocker HMR 1883 (1-[[5-[2-(5-chloro-o-anisamido)ethyl]-methoxyphenyl]sulfonyl]-3-m ethylthiourea) shows marked antifibrillatory activity in the dose range of 3 mg/kg to 10 mg/kg i.v. in various experimental models without affecting blood glucose levels. In order to investigate in a head to head comparison glibenclamide and HMR 1883 with respect to their influence on IPC, experiments were performed in rabbits with ischemia-reperfusion using myocardial infarct mass as final read out. Male New Zealand White rabbits (2.6-3.0 kg) were subjected to 30-min occlusion of a branch of the left descending coronary artery (LAD) followed by 2-h reperfusion. For IPC experiments the LAD was additionally occluded for two periods of 5 min, each followed by 10-min reperfusion, before the long-term ischemia. Infarct mass was evaluated by TTC staining and expressed as a percentage of area at risk. Rabbits (n=7/group) were randomly selected to receive (i.v.) saline vehicle 5 min prior to the 30-min occlusion period in infarct studies without IPC or to receive glibenclamide (0.3 mg/kg) or HMR 1883 (3 mg/kg) in IPC experiments, these substances being given 5 min prior to the first preconditioning or 5 min prior to the long-term ischemia of 30 min. Myocardial risk mass as a percentage of left ventricular mass did not differ between groups. The same was true for the ratio of left ventricular mass to 100 g body weight. Myocardial infarct mass as a percentage of the area at risk in the saline vehicle group without IPC was 41+/-3%. Whereas glibenclamide significantly increased infarct mass (from 41+/-3% to 55+/-4%), HMR 1883 did not affect it. IPC reduced infarct mass from 41+/-3% to 21+/-4% (P<0.05 vs. control without IPC). Glibenclamide given prior to IPC or prior to the long-term ischemia totally abolished the IPC effect (42+/-2% and 55+/-4%, respectively; P<0.05 vs. control). In contrast, HMR 1883 under the same conditions did not affect infarct size when given prior to IPC or prior to the long-term ischemia (21+/-3% and 26+/-2%, respectively). The monophasic action potential duration (MAP50) was reduced from 103+/-3 ms under normoxic conditions to 82+/-2 ms, 5 min after ischemia in the absence of drugs. This ischemia-induced shortening of the MAP was prevented by both HMR 1883 (MAP50 103+/-3 ms) and glibenclamide (MAP50 106+/-3 ms). In conclusion, although both K(ATP) channel blockers prevented ischemia-induced shortening of MAP, HMR 1883 did not abolish the beneficial effects of IPC on myocardial infarct mass in rabbits, whereas glibenclamide totally reversed this cardioprotective effect of IPC. This suggests that the sarcolemmal ATP-sensitive potassium channels are not involved in the mechanism of IPC.

Ischemic preconditioning and infarct mass: the effect of hypercholesterolemia and endothelial dysfunction

In an experimental model of atherosclerosis we investigated whether rabbits fed an atherogenic diet (0.25% cholesterol, 3% coconut oil) develop endothelial dysfunction accompanied with increased infarct mass compared to normal fed rabbits and, whether hypercholesterolemia would interfere with the beneficial outcome of ischemic preconditioning observed in normal rabbits. After four weeks on either a normal or an atherogenic diet, New Zealand White rabbits (n=7 in each group) were subjected to 30 min of myocardial ischemia by occlusion of a branch of the left anterior descending coronary artery (LAD) followed by 2 hours of reperfusion (infarct studies). For ischemic preconditioning experiments, LAD was additionally occluded twice for 5 min followed by 10 min reperfusion before the long-lasting (30 min) ischemia. Infarct mass was evaluated by triphenyl-tetrazolium staining. Besides the assessment of aortic endothelium-dependent function and NO-release, aortic and cardiac vessels were inspected for atherosclerotic lesions. Total cholesterol serum levels in rabbits on an atherogenic diet were significantly higher (15.3+/-2.7 mmol/L) than those on a standard diet (0.65+/-0.08 mmol/L). The aortas and heart vessels were without any histological evidence of atherosclerosis, whereas endothelial dysfunction and significantly reduced calcium-ionophore stimulated endothelial NO-release were found in isolated aortic rings of hypercholesterolemic animals. Rabbits on a standard diet showed an infarct mass (related to the area at risk) of 41+/-33%, which was reduced to 21+/-2% by ischemic preconditioning (49% decrease, p<0.05). In rabbits on an atherogenic diet, infarct mass was significantly increased to 63+/-3% (52% increase versus standard diet). Interestingly, hypercholesterolemia did not affect the beneficial influence of ischemic preconditioning; infarct mass (21+/-3%, p<0.05 vs hypercholesterolemia) was similar to rabbits on a standard diet with ischemic preconditioning. Our results show that experimental hypercholesterolemia increases infarct mass in nonpreconditioned hearts but it does not interfere with the reduction of infarct mass elicited by preconditioning. This may suggest that NO produced by the endothelium is not a prime factor in the cardioprotective mechanism of preconditioning.

Effects of ginger on gastroduodenal motility

The effect of a ginger rhizome extract (2 x 100 mg) was studied on fasting and postprandial gastroduodenal motility with stationary manometry in 12 healthy volunteers. The results showed that: the interdigestive antral motility was significantly increased by ginger during phase III of the migrating motor complex; the volunteers also had a significantly increased motor response to a test meal in the corpus; a trend to an increased motor response during ginger treatment was seen in all other regions of interest. Oral ginger improves gastroduodenal motility in the fasting state and after a standard test meal.

Transcatheter closure of secundum atrial septal defects with the new self-centering Amplatzer Septal Occluder

AIMS

The study was set up to find out whether a new self-centering prosthesis for transcatheter closure of secundum atrial septal defects could overcome the disadvantages of previously described devices.

METHODS AND RESULTS

Fifty-two consecutive patients with a significant atrial septal defect were considered for transcatheter closure with the Amplatzer Septal Occluder. The device, made of a Nitinol and polyester fabric mesh, provides a different approach to defect occlusion by stenting the atrial septal defect up to a stretched diameter of 26 mm. Three infants whose large defects were demonstrated on a transthoracic echocardiogram were excluded from transcatheter treatment. On transoesophageal echocardiography, 49 defects ranged from 6-26 mm, in one adult the defect measured 28 mm and this patient was excluded from attempted transcatheter closure. At cardiac catheterization in five further patients, devices were not implanted, in two because the stretched diameter exceeded 26 mm and in three the device was withdrawn because it was unstable or compromised the mitral valve. Thus, device closure was performed in 43 patients. At follow-up after 3 months the complete closure rate was 97%.

CONCLUSION

The self-centering Amplatzer Septal Occluder is very efficient and user-friendly and offers interventional closure in 83% of an unselected group of patients presented with an atrial septal defect.

[Atrial ectopic tachycardia in infancy caused by tumor of the interatrial septum]

A case of atrial ectopic tachycardia in an infant probably caused by a small tumor in the interatrial septum is presented. The arrhythmia was successfully treated with amiodarone. Several histologic abnormalities are known to cause AET, but an intracardiac tumor detectable by two-dimensional echocardiography is extremely rare. AET -especially in childhood-as well as cardiac tumors show a tendency to regression, so that even in this case medical treatment should be the first therapeutic choice. Interventional or surgical treatment is required just for those patients with AET this is resistant to medical treatment or reoccurs after finishing the medical treatment.

The relationship between DNA content, clinicopathology and prognosis in enteropancreatic carcinoids

BACKGROUND/AIMS

The clinical behavior of carcinoid tumors is sometimes difficult to determine from their histological appearance. The aim of the present study was to evaluate whether the DNA distribution pattern seen in carcinoid tumors can be correlated with histopathological parameters and the patient's clinical course and prognosis.

METHODOLOGY

The paraffin-embedded material of 44 enteropancreatic tumors underwent deparaffinization, was rehydrated, and mechanically and enzymatically processed into a single cell solution. For evaluation of the DNA histogram, analysis was performed with the help of an automatic single cell cytophotometric study.

RESULTS

A correlation was seen between the DNA content and tumor stage (p = 0.01), radicalness of surgery (p = 0.03), tumor localization (p = 0.02) and patient's age (p = 0.05). In univariate analysis, patient's age (p = 0.04), tumor localization (p = 0.03), tumor stage (p = 0.0001), radicalness of surgery (p = 0.0006) and DNA content (p = 0.01) influenced prognosis. In multivariate analysis including these parameters, only tumor stage had an independent influence on prognosis.

CONCLUSION

The clinical relevance of DNA measurement in carcinoid tumors is still unknown.

Hypercholesterolemia is associated with enhanced angiotensin AT1-receptor expression

Low-density lipoprotein increases the AT1-receptor gene expression in vascular smooth muscle cells. To elucidate whether elevated cholesterol serum levels upregulate the AT1 receptor and its functional response to angiotensin II in vivo, we compared 1) the vasoconstrictive effect of angiotensin II and 2) the level of expression of the vascular AT1 receptor in aortas of normocholesterolemic and hypercholesterolemic rabbits. Contraction experiments on isolated aortic rings showed that the angiotensin II-induced vasoconstriction was increased in hypercholesterolemic New Zealand White rabbits compared with normocholesterolemic New Zealand White rabbits. This difference in the angiotensin II-induced vasoconstriction was caused by a twofold increase in the density of cell surface AT1 receptors in hypercholesterolemic rabbits, as assessed by radioligand binding assays. The enhanced expression of AT1 receptors on the surface of these vascular cells was caused by elevated steady-state levels of the AT1-receptor mRNA to 220 +/- 35% in aortas excised from hypercholesterolemic rabbits compared with levels in aortas from normocholesterolemic rabbits, as measured by Northern blot analysis. These data indicate that hypercholesterolemia is associated with upregulation of expression and function of vascular AT1 receptors in vivo. This suggests a novel mechanism by which hypercholesterolemia could be involved in the onset and progression of chronic vascular diseases such as hypertension and arteriosclerosis if the phenomenon is confirmed in humans.

Purification and chemical characterization of staphyloferrin B, a hydrophilic siderophore from staphylococci

This paper describes the chemical characterization of staphyloferrin B, a new complexone type siderophore isolated from low iron cultures of Staphylococcus hyicus DSM 20459. Purification of the very hydrophilic metabolite was achieved by anion exchange high performance liquid chromatography HPLC. Mass spectrometry showed a molecular mass of 448 amu. Hydrolysis with 8 M HCl revealed the presence of L-2,3-diaminopropionic acid, citrate, ethylenediamine and succinic semialdehyde. The connections between the four building blocks were determined by two-dimensional nuclear magnetic resonance measurements. UV/Vis and circular dichroism spectra are consistent with the proposed structure, which could also be confirmed by precursor feeding. The siderophore activity of staphyloferrin B was demonstrated by iron transport measurements.

Surgical treatment of metastatic colorectal adenocarcinoma

Ninety-one patients with recurrent or metastatic colorectal adenocarcinomas were studied according to the anatomic areas of the recurrent tumor. In Group A, 30 patients with anastomotic recurrence, diagnosis was made in the majority within two years from initial surgery; most of them had specific symptomatology. A significant number of patients had blood in the stools. In half of the patients, complete resection of the recurrent tumor was feasible. In Group B, 47 patients with intra-abdominal recurrence, there was some delay in diagnosis; the symptomatology was less specific, and fewer patients were rendered free of tumor following reresection. The medial survival and estimated five-year survival rate were, in both groups, strongly related to the completeness of the resection. In Group C, with distant metastasis (eight patients with pulmonary and six with liver metastasis), the disease-free interval was longer compared to the previous groups. The metastatic tumor was found in three patients, four or more years after the initial surgery. The medial survival was the same as in the two other subgroups with complete resection of the recurrent tumor.

Inhibitors of fibrinolysis in diabetic children, mothers, and their newborn

Late diabetic complications are often related to vascular changes and formation of thrombi in the altered vasculature. Contributing factors to thrombosis susceptibility of diabetic patients include changes in clotting factors, platelets, and inhibition of fibrinolysis. We have measured various fibrinolytic inhibitors in the blood of diabetic children, diabetic pregnant women and their offspring, and healthy controls. Inhibitors studied included 1) fast (immediate) antiplasmin, 2) slow (progressive) antiplasmin, 3) alpha-2-macroglobulin, and 4) alpha-1-antitrypsin. It appears from our study that high fast-antiplasmin levels, and low or missing slow-antiplasmin levels are characteristic of diabetic patients and of newborn of diabetic mothers. The reason for high fast-antiplasmin levels is not clear: Levels are not connected with the age of the patient or duration of diabetes, and are not elevated in response to a fibrinolytic process (fibrin decomposition products could not be shown to be present in the serum of diabetic children). Alpha-2-macroglobulin was significantly higher and alpha-1-antitrypsin significantly lower in diabetic women than in controls. In the other groups of patients studied differences in these inhibitors from the appropriate control groups were not statistically significant.

The fibrinolysin system and its relationship to disease in the newborn

The fibrinolysin system is incomplete in newborn infants. Lack of serum plasminogen in premature newborn has an important role in the pathophysiology of the respiratory distress syndrome since alveolar fibrin deposits cannot be eliminated. Urokinase activated human plasmin has increased the survival rate of infants with respiratory distress syndrome. Plasminogen given I.V. at birth has reduced the incidence and the severity of respiratory distress syndrome, in a randomized double-blind study of 500 premature infants. Death in the plasminogen recipient group occurred only among infants born to mothers with bleeding complications of pregnancy. Plasmin inhibitors measured with a functional assay were the highest in this group of infants, serum plasminogen was the lowest; when activator and purified human plasminogen were added to the serum, fibrinolytic activity was elicited in excess of the plasminogen added. It is suggested that plasminogen and/or plasmin inhibitors may be abnormal fetal variants in infants born to mothers with bleeding complications.

Response of hematopoietic cell lines derived from patients with Down's syndrome and from normal individuals to mitomycin C and caffeine

Eight human hematopoietic cell lines, five derived from blood of patients with Down's syndrome (DS) and three from normal persons, were treated with mitomycin C (MC) and caffeine at various dose levels and for various durations. An increased rate of chromosome aberrations was found in all treated cultures. The extent of aberrations was correlated with the dose levels and duration; no difference occurred in sensitivity between the group of DS and normal lines at all dose levels and for all durations. Studies on the effect of MC severely reduced cell viability, but no difference was found in the rate of reduction of viable cell counts between DS and normal lines. Inhibition of mitoses by MC in DS lines, however, seemed stronger than that in normal lines.

Impaired lymphocyte blastogenic response in patients with colon adenocarcinoma: effects of disease and age

The in vitro blastogenic response of 76 patients with colon adenocarcinoma and 29 age-matched normal healthy volunteers was compared. An age-related decline in cellular immunocompetence was observed in both the patient and control group. Within each age interval, the patients' blastogenic responses were lower than the controls' and the rate of decline of the blastogenic response in the patient group was greater in magnitude, suggesting that their disease state also contributed to loss of cellular immunocompetence. Thus, both increasing age and presence of tumor are factors that contribute to the decline the immunocompetence in patients with colon adenocarcinoma.