Vascular protective effect of aspirin and rivaroxaban upon endothelial denudation of the mouse carotid artery.

While in recent trials the dual pathway inhibition with aspirin plus rivaroxaban has shown to be efficacious in patients with atherosclerotic cardiovascular disease, little is known about the effects of this combination treatment on thrombus formation and vascular remodelling upon vascular damage. The aim of this study was to examine the effects of aspirin and/or rivaroxaban on injury-induced murine arterial thrombus formation in vivo and in vitro, vessel-wall remodelling, and platelet-leukocyte aggregates. Temporary ligation of the carotid artery of C57BL/6 mice, fed a western type diet, led to endothelial denudation and sub-occlusive thrombus formation. At the site of ligation, the vessel wall stiffened and the intima-media thickened. Aspirin treatment antagonized vascular stiffening and rivaroxaban treatment led to a positive trend towards reduced stiffening. Local intima-media thickening was antagonized by both aspirin or rivaroxaban treatment. Platelet-leukocyte aggregates and the number of platelets per leukocyte were reduced in aspirin and/or rivaroxaban treatment groups. Furthermore, rivaroxaban restricted thrombus growth and height in vitro. In sum, this study shows vascular protective effects of aspirin and rivaroxaban, upon vascular injury of the mouse artery.

SFRR-E Young Investigator AwardeeNOXing out stroke: Identification of NOX4 and 5as targets in blood-brain-barrier stabilisation and neuroprotection.

Stroke is the second leading cause of death with high blood pressure and female gender being the main risk factors. However, only one treatment is available and with many contraindications, which leaves more than 80% of patients untreated. Over a thousand experimental stroke treatments have remained unsuccessful in the clinic. In preclinical research, low reproducibility and publication bias have been suggested as causes of low translatability success. NADPH oxidases might be key players in stroke via their unique role as a major and/or early source of reactive oxygen species (ROS). To clarify the role of the different NOX isoforms (1, 2, 4, and 5) we analysed different KO and KI models. Previous literature claimed a role for NOX2. Using both a meta-analytical and a blinded randomised controlled trial approach, we however find that NOX2 plays only a minor role and publication bias and lack of power perturbed the published literature. We earlier showed a detrimental role of NOX4 in stroke and extend this based on cell-specific KO animals that endothelial but not vascular smooth muscle cells are the major source of NOX4 in stroke. Mice do not express the human NOX5 gene. Using a NOX5 KI model, we show that endothelial NOX5 induces hypertension and increased stroke risk, particularly in females. In human hypertension, NOX5 is upregulated, and women have a higher stroke risk. Thus NOX5 might be a missing link in this context. In conclusion, NOX4 and NOX5, but not NOX2, are promising targets for the development of new neuroprotective therapies for ischemic stroke. A priori power and sample size calculation as well as reporting of also negative data is essential with respect to preclinical validation of therapeutic targets.

[Diagnostic image (84). A woman with persisting perianal fissures]. / Diagnose in beeld (84). Een vrouw met persisterende anusfissuren.

A 63-year-old woman had perianal fissures, which were caused by an amelanotic melanoma of the anus.

Transanal endoscopic microsurgery for rectal cancer.

If curation is intended for rectal cancer, total mesorectal excision with autonomic nerve preservation (TME) is the gold standard. Transanal resection is tempting because of low mortality and morbidity rates. However, inferior tumour control, provoked by the limitations of the technique, resulted in its cautious application and use mainly for palliation. Transanal endoscopic microsurgery (TEM) is a minimal invasive technique for the local resection of rectal tumours. It is a one-port system, introduced transanally. An optical system with a 3D-view, 6-fold magnification and resolution as the human eye, together with the creation of a stabile pneumorectum, and specially designed instruments allow full-thickness excision under excellent view and a proper histological examination. The technique can also be applied for larger and more proximal tumours. Mortality, morbidity as well as incomplete excision rates are minimal. Local recurrence and survival rates seem comparable to TME in early rectal cancer. TEM is the method of choice when local resection of rectal cancer is indicated. Results justify a re-evaluation of the indications for the local excision of rectal cancer with a curative intent.

Chronic measurement of cardiac output in conscious mice.

We describe the feasibility of chronic measurement of cardiac output (CO) in conscious mice. With the use of gas anesthesia, mice >30 g body wt were instrumented either with transit-time flow probes or electromagnetic probes placed on the ascending aorta. Ascending aortic flow values were recorded 6-16 days after surgery when probes had fully grown in. In the first set of experiments, while mice were under ketamine-xylazine anesthesia, estimates of stroke volume (SV) obtained by the transit-time technique were compared with those simultaneously obtained by echocardiography. Transit-time values of SV were similar to those obtained by echocardiography. The average difference +/- SD between the methods was 2 +/- 7 microl. In the second set of studies, transit-time values of CO were compared with those obtained by the electromagnetic flow probes. In conscious resting conditions, estimates +/- SD) of cardiac index (CI) obtained by the transit-time and electromagnetic flow probes were 484 +/- 119 and 531 +/- 103 ml x min(-1) x kg body wt(-1), respectively. Transit-time flow probes were also implanted in mice with a myocardial infarction (MI) induced by ligation of a coronary artery 3 wk before probe implantation. In these MI mice (n = 7), average (+/- SD) resting and stimulated (by volume loading) values of CO were significantly lower than in noninfarcted mice (n = 15) (resting CO 16 +/- 3 vs. 20 +/- 4 ml/min; stimulated CO 20 +/- 5 vs. 26 +/- 6 ml/min). Finally, using transfer function analysis, we found that, in resting conditions for both intact and MI mice, spontaneous variations in CO (> 0.1 Hz) were mainly due to those occurring in SV rather than in heart rate. These data indicate that CO can be measured chronically and reliably in conscious mice, also in conditions of heart failure, and that variations in preload are an important determinant of CO in this species.

Chronic myocardial infarction in the mouse: cardiac structural and functional changes.

OBJECTIVES: We studied the effects of chronic left coronary artery ligation on cardiac structure and function in the mouse. METHODS: Morphometric studies of the left ventricle were performed in coronary artery-ligated and sham-operated animals at one, two, three and five weeks after surgery. The fraction of DNA-synthesizing cells was determined as the fraction of cells incorporating 5'-bromo-2'-deoxyuridine, which was infused by osmotic minipumps one week before sacrifice. Collagen content of the septum was determined morphometrically. Left ventricular pressure and its derivatives were measured in separate groups of animals at one and three weeks after surgery. RESULTS: Ligation of the main left coronary artery resulted in antero-apical infarction of the left ventricular wall, involving approximately 40% of left ventricular circumference. Infarction resulted in thinning of the infarcted area and left ventricular dilatation. DNA synthesis increased, peaking between one and two weeks in the border-zone of the infarct (22-fold), septum (ten-fold) and right ventricle (five-fold). At five weeks, DNA synthesis was still increased in the border zone of the infarct. Septal collagen content increased approximately eight-fold in infarcted mice at two weeks, and decreased thereafter; it was still significantly elevated at five weeks. Left ventricular systolic pressure, and maximal positive and negative dP/dt decreased following infarction; left ventricular end-diastolic pressure was elevated at three weeks, but this effect was not statistically significant. CONCLUSION: These data provide basic information on changes in cardiac structure and function in mice following chronic coronary artery ligation. They indicate the feasibility of induction of chronic myocardial infarction in this species. Furthermore, they show the similarity of cardiac structural and functional consequences of chronic myocardial infarction in mice to those previously described in rats.

[Rubberband ligation of hemorrhoids: symptoms almost gone after 6 weeks, but many patients need retreatment in the long run]. / Rubberbandligering van hemorroïden: klachten na 6 weken veelal verdwenen, maar nieuwe behandeling op langere termijn bij veel patiënten noodzakelijk.

OBJECTIVE: To assess the short and middle-long term results of outpatient treatment of internal haemorrhoids by rubber band ligation. DESIGN: Prospective. METHODS: The results and the complications of rubber band ligation were assessed in a group of consecutive patients treated for internal haemorrhoids by one surgeon in March 1995-September 1997 in the Laurentius Hospital Roermond, the Netherlands. Middle-long term results were assessed by an independent examiner who questioned the patients by phone. RESULTS: Ninety-four patients were treated: 43 women and 51 men, with a mean age of 51 years (range: 23-80). After 6-18 weeks 80 out of 90 accessible patients (89%) were symptom-free, 71 (79%) of them after one treatment. Serious complications were not reported. However, the days after treatment mild complaints of anal urgency and pain were present in 16 patients (20%). Twenty-three patients underwent sigmoidoscopy. In 10 patients (43%) adenomatous polyps (in 9 patients) or diverticulosis (in 1 patient) were found. After a mean of 18 months (range: 6-31) 32 patients (41%) (still) had anal complaints compatible with haemorrhoids. CONCLUSION: Rubber band ligation is an easy and safe outpatient treatment of internal haemorrhoids. Most patients become symptom-free, often after one treatment. However, about 40% of the patients have recurrent symptoms within a few years after initial treatment.

Cardiac function in a rat model of chronic aortic stiffness.

Cardiac function was investigated in conscious normotensive rats in which increased aortic stiffness was produced as a result of vascular calcium overload after treatment with vitamin D3 plus nicotine (VDN rats, n = 16; controls, n = 17). Baseline stroke volume, cardiac output, and cardiac response to a venous volume overload were unchanged after 1 mo of exposure to increased aortic stiffness, as were baseline venous return and total vascular capacitance. The latter was estimated from the change in mean circulatory filling pressure after modification of circulatory volume. Cardiovascular reflexes were modified in VDN rats. Bradycardia evoked by an increase in arterial PCO2 (PaCO2) or hypotensive hemorrhage was more pronounced. The PaCO2-induced bradycardia was accompanied by a fall in cardiac output in VDN rats but not in controls. In VDN rats, the attenuation of sympathetic reflexes may explain the slower recovery of blood pressure after hypotensive hemorrhage. In conclusion, a chronic increase in aortic stiffness does not compromise cardiac performance, but cardiovascular reflexes are impaired in VDN rats. Whether this is because of the increase in aortic stiffness or the effect of VDN treatment on the baroreceptors or other components of the reflex arc remains to be elucidated.

Dysmenorrhea related to gallstone spilling after laparoscopic cholecystectomy.

A 28-year-old woman is presented with severe dysmenorrhea since a previous laparoscopic cholecystectomy for cholelithiasis. Spilled gallstones were embedded in the Douglas cavity and the visceral peritoneum of the genitalia interna. Dysmenorrhea was treated successfully by laparotomic hysterectomy and removal of all gallstones.

Time-related normalization of maximal coronary flow in isolated perfused hearts of rats with myocardial infarction.

BACKGROUND: In the present study, we investigated the time dependency and regional differences of the vascular adaptation of the myocardium after myocardial infarction (MI) in rats. METHODS AND RESULTS: MI was induced by total occlusion of the left anterior descending coronary artery. Time-dependent adaptation of the coronary vasculature was determined by histological staining of endothelial cells and measurement of basal and maximal coronary flow at days 0, 4, 7, 21, 35, and 90 after surgery in isolated retrogradely perfused hearts of sham-operated and infarcted rats. Cardiac function was determined during anterograde perfusion. In a separate group of experiments, regional myocardial flow was measured with radiolabeled microspheres in sham-operated and infarcted hearts to determine local differences in adaptation. Basal coronary flow was completely normalized within 7 days, whereas maximal coronary flow was not normalized until 35 days after MI. Normal growth, as observed in sham-operated hearts, resulted in a parallel increase in coronary flow and tissue mass from day 7 to 35 after surgery. In contrast, the increase in coronary flow was lower than the hypertrophic response in the right ventricles and septa of infarcted hearts, whereas a parallel increase in tissue mass and coronary flow was observed in the left ventricles of these hearts. These functional data were supported by structural data that showed the presence of numerous and dilated vessels, especially in the border zone of the infarcted and noninfarcted tissue. CONCLUSIONS: These observations demonstrate that vessel growth, predominantly in the region adjacent to the infarcted zone, results in complete normalization of coronary vasodilatory capacity within 35 days after MI.

A rare complication of implanted central-venous access devices: catheter fracture and embolization.

Totally implanted central-venous access devices are frequently used for the administration of chemotherapy or parenteral nutrition. Catheter fracture is a rare complication of these devices, with an estimated rate of 0.1%. We have lately seen three cases of catheter fracture with embolization of a catheter fragment to the heart and pulmonary vessels. These cases are described in this article. Catheter fracture is caused by intermittent compression of the catheter between the clavicula and the first rib, which can occur when the catheter has been inserted too far medially. When, on an X-ray of the chest, the catheter is shown to be compressed at the point where the clavicula crosses the first rib, or when infusion through the device suddenly becomes difficult, the chance of catheter fracture is high and the device should be removed.

Parotidectomy for parotid tumours: 19-year experience from The Netherlands.

A total of 150 patients were treated for parotid tumours over a period of 19 years. In 94 per cent superficial or total parotidectomy was performed. Histological diagnosis of the resected specimen revealed pleomorphic adenoma in 92 patients (61 per cent), Whartin's tumour in 30 (20 per cent), various benign neoplasms in 11 (7 per cent) and malignant tumour in 17 (11 per cent). After a mean follow-up of 7.7 years, no recurrence of a benign tumour was seen. Malignant tumours recurred in five patients. Permanent partial facial paralysis was seen in 4 per cent of patients after surgery for benign lesions. Frey's syndrome was observed in 43 per cent of patients, and was not prevented by resection of the auriculotemporal nerve.

DNA synthesis in the non-infarcted cardiac interstitium after left coronary artery ligation in the rat: effects of captopril.

Effects of Captopril. Journal of Molecular and Cellular Cardiology (1991) 23, 1245-1253. This study was undertaken to investigate the alterations in interstitial DNA synthesis and collagen content in the non-infarcted left and right ventricle after induction of a myocardial infarction (MI) in the rat. MI was induced by ligation of the left anterior descending coronary artery. All animals received 5-Bromo-2'-deoxyUridine (BrdU), via a subcutaneous osmotic minipump, one day before sacrifice, to quantitate DNA synthesis. A transient rise in BrdU incorporation was found in both ventricles. Peak levels were found at day 7 and 14 after infarct induction. BrdU incorporation had returned to control levels 3 weeks after infarct induction. By using anti BRDU--anti-laminin immuno- double staining DNA synthesis was localized mainly in the cardiac interstitium. Concomitantly, a sustained increase in collagen content, measured as the Sirius red positive area on cross sections, was found from day 7 after infarct induction. No changes were found in sham animals. In the second part of the study the effects of the angiotensin I converting enzyme inhibitor captopril and the arteriolar vasodilator hydralazine on MI induced interstitial DNA synthesis and collagen content were investigated. Captopril reduced both the increase in DNA synthesis and collagen content. Hydralazine did not affect interstitial DNA synthesis, but reduced the MI induced collagen content. Both drugs had no effects in sham animals. We conclude that induction of a myocardial infarction stimulates interstitial DNA synthesis and increases the collagen content in the non-infarcted areas of the heart. Interstitial DNA synthesis is dependent on the angiotensin I converting enzyme in a direct manner independent from afterload changes.

Two weeks of intermittent dobutamine therapy restores cardiac performance and inotropic responsiveness in conscious rats with heart failure.

Dobutamine is frequently used for acute therapy in heart failure. In the present study, the hemodynamic effects of long-term intermittent dobutamine therapy were investigated in conscious rats with heart failure. Rats with healed myocardial infarctions received two i.p. injections of dobutamine per day for 2 weeks. Hemodynamic measurements were performed 90-180 min after the last injection. Two weeks of intermittent dobutamine significantly restored all hemodynamic changes induced by infarction. The maximal cardiac output during volume loading was depressed due to infarction and dose-dependently restored by 2 weeks of intermittent dobutamine. An increased stroke volume accounted for this improvement since the heart rate was not altered. In order to investigate changes in adrenergic responsiveness, the effects of acute dobutamine in nontreated and 2 weeks of dobutamine-treated infarcted rats were compared to those in control rats. Whereas chronotropic responses to acute dobutamine were comparable for all experimental groups, the inotropic response was reduced in nontreated infarcted rats but dose-dependently restored after 2 weeks of intermittent dobutamine therapy. From the data, we conclude that 2 weeks of intermittent dobutamine therapy in conscious rats with healed myocardial infarcts improved cardiac performance and restored the inotropic response to acute dobutamine administration. Data indicate that dobutamine has a long-term effect on cardiac function, which differs from the acute inotropic effect.

Delayed but not immediate captopril therapy improves cardiac function in conscious rats, following myocardial infarction.

After myocardial infarction, the renin-angiotensin system is found to be activated. While this response may be beneficial in acute failure, it could be detrimental in chronic stages. Therefore effects of captopril therapy were investigated during early and later phases after myocardial infarction in conscious rats, chronically instrumented for hemodynamic measurements. Hemodynamics were measured at baseline and after stimulating the heart by a volume load (cardiac function curve). Myocardial infarction decreased baseline cardiac output and impaired cardiac function, without effects on baseline mean arterial pressure, central venous pressure and heart rate. Captopril given 3 to 5 weeks after infarction improved cardiac function in a dose-dependent manner by increasing stroke volume, whereas stroke work was not affected. In contrast, captopril given from 1 to 21 days after infarction did not lead to improved cardiac function; instead, tachycardia together with a decreased stroke volume suggested deterioration, rather than improvement, of cardiac function. These data indicate that captopril therapy in chronically infarcted conscious rats improved cardiac function when treatment was started after completion of the healing process, but that early treatment not only failed to improve ventricular function, but may have a deleterious effect of the heart.

Beneficial hemodynamic effects of two weeks' milrinone treatment in conscious rats with heart failure.

Milrinone is a phosphodiesterase inhibitor which combines vasodilating effects with inotropic effects. Hemodynamic improvement after acute administration and increased survival with chronic milrinone therapy in rats with heart failure have been reported before, and suggest long-term hemodynamic improvement. However, no detailed hemodynamic studies are available on prolonged milrinone therapy in rats with heart failure. Therefore, the hemodynamic effects of 2 weeks' milrinone therapy were now investigated in conscious rats with heart failure due to myocardial infarction. The effects were compared to hemodynamic changes after acute administration. Acute milrinone increased the baseline cardiac output in infarcted rats by increasing heart rate rather than stroke volume. However, the maximal cardiac output achieved when the heart was stimulated through a volume load was improved due to increased stroke volume as well as increased heart rate. The increase in maximally stimulated cardiac output after acute milrinone was found to be related to infarct size. Two weeks' milrinone therapy in chronically infarcted rats dose dependently restored the hemodynamic changes which were caused by infarction. In contrast to acute administration, two weeks' milrinone restored cardiac function without an increase in heart rate. The effects were achieved at a rate of administration which presumably has no acute inotropic effects. The data indicate that acute milrinone in infarcted rats has vasodilating effects. Positive inotropic effects, possibly masked by concomitant venodilatation at baseline conditions, became overt after stimulation by volume loading. Long-term milrinone dose dependently restored cardiac function in infarcted rats without effects on heart rate or mean arterial pressure, suggesting that different mechanisms may be involved.

Cross-linking of both Fc gamma RI and Fc gamma RII induces secretion of tumor necrosis factor by human monocytes, requiring high affinity Fc-Fc gamma R interactions. Functional activation of Fc gamma RII by treatment with proteases or neuraminidase.

Cross-linking of Fc gamma R on human monocytes with human IgG has been shown to induce secretion of the inflammatory and immunoregulatory cytokine TNF. In the present study we examined the role of both constitutively expressed monocyte Fc gamma R, the 72-kDa high affinity Fc gamma R (Fc gamma RI), and the 40-kDa low affinity receptor (Fc gamma RII), in the induction of TNF secretion. On the basis of preferential binding of the Fc moiety of murine mAb of different isotype, Fc gamma RI and Fc gamma RII were selectively cross-linked by using either solid-phase murine (m)IgG2a, or solid-phase mIgG1, respectively. On freshly isolated, untreated monocytes only cross-linking of Fc gamma RI with solid-phase mIgG2a induced TNF secretion. The interaction between Fc gamma RII and mIgG1 could be enhanced by treatment of monocytes with proteases or with the desialylating enzyme neuraminidase. After treatment of monocytes with these enzymes, TNF secretion was effectively induced by solid-phase mIgG1, apparently through cross-linking of Fc gamma RII. However, mIgG1-induced TNF secretion differed between protease-treated monocytes from high responder individuals and monocytes from low responder individuals, TNF secretion being considerably less in the latter population. Protease-treated monocytes and mononuclear cells from individuals with an inherited defect in cell membrane expression of Fc gamma RI were induced to secrete TNF by solid-phase human IgG, confirming the capacity of Fc gamma RII to induce TNF secretion. It was not possible to induce TNF secretion by cross-linking Fc gamma RI or Fc gamma RII with anti-Fc gamma R mAb and soluble or solid-phase anti-mIgG, indicating that high affinity Fc-Fc gamma R interactions are necessary to induce release of this cytokine.

Acute hemodynamic effects of coronary artery ligation in conscious rats.

Because of the growing interest in the use of coronary artery ligation (CAL) in rats as a model for studies on heart failure, we have investigated the acute hemodynamic changes following CAL in conscious rats. Animals were equipped for measurement of cardiac output (CO), arterial pressure (MAP), and central venous pressure (CVP). These parameters were measured before CAL, immediately after, and 24 h after. Furthermore, peak CO, obtained by rapid infusion of 12 ml Ringer's solution (in 1 min) was measured 2 days before and 1 day after CAL. CAL resulted in immediate reduction of CO, because of reduced stroke volume (SV). CO as well as SV were inversely correlated with infarct size as determined 24 h after CAL. Heart rate (HR) and MAP did not change. Twenty-four hours later, CO was still reduced. MAP was now reduced, possibly as a result from resetting of nervous reflex mechanisms. Before CAL, peak CO and SV were similar in CAL and sham animals. At 24 h after CAL, these parameters were greatly reduced in CAL rats. Peak values were strongly correlated to infarct size. Results indicate that CAL in rats leads to hemodynamic changes similar to the ones observed following myocardial infarction in man. Cardiac function is related to infarct size and is altered both at rest and during maximal stimulation.