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.

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.

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.

Evidence of involvement of tumor necrosis factor in adverse reactions during treatment of kidney allograft rejection with antithymocyte globulin.

Serial plasma concentrations of the pyrogenic cytokines tumor necrosis factor and interleukin-1 beta were measured during treatment of acute renal allograft rejection with antithymocyte globulin in 7 consecutive kidney transplant recipients. TNF and IL-1 beta were measured with specific enzyme-linked immunosorbent assays. In 6 of 7 patients TNF could not be detected in the plasma before the start of the ATG infusion. During the first ATG infusion, which was accompanied by fever and other side effects in all patients, plasma TNF levels were shown to be elevated, ranging between 100 and 700 pg/ml. During the second ATG infusion, when side effects were minimal or absent, plasma TNF levels were only slightly raised. Circulating IL-1 beta could not be detected in any of the patients before or during ATG infusion. Additional experiments showed that TNF is rapidly secreted in cultures of peripheral blood mononuclear cells incubated with both ATG and the monoclonal antibody OKT3. These findings suggest that side effects, including fever and chills, during antilymphocyte antibody infusion are related to increased plasma levels of the pyrogenic cytokine TNF.

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.

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.

[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.

[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.

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.

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.

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.

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.

T cell-mediated production of tumour necrosis factor-alpha by monocytes.

The aim of this study was to examine the tumour necrosis factor (TNF)-alpha production by peripheral blood mononuclear cells activated by mitogens. Considerable amounts of TNF-alpha, ranging from 1.0 to 5.0 ng/ml, were present in the supernatants of cultures of human peripheral blood mononuclear cells (PBMC), stimulated with either the anti-CD3 monoclonal antibody OKT3 or the lectin phytohaemagglutinin (PHA). The amount of TNF-alpha secreted in the supernatant was closely correlated to the degree of T cell proliferation in such cultures, as measured by [3H]TdR incorporation. In the absence of proliferating T cells the mitogens did not induce secretion of TNF-alpha by monocytes. Supernatants of proliferating T cells were shown to induce TNF-alpha production by monocytes. The macrophage-activating factor gamma interferon (IFN-gamma) was also shown to induce, in the absence of endotoxin, TNF-alpha secretion by monocytes in a dose-dependent manner. The induction of TNF-alpha production by supernatants of proliferating T cells could largely be abrogated by passaging the supernatants on an anti-IFN-gamma column before adding them to the monocytes. It is therefore concluded from this study that the production of TNF-alpha by monocytes can be induced by proliferating T cells and that this induction can largely be attributed to the T cell lymphokine IFN-gamma.

Role of sensory renal nerves in the development of spontaneous hypertension in rats.

In order to study the role of afferent renal nerves in the development of spontaneous hypertension, 3-4 weeks old uninephrectomized spontaneously hypertensive rats were deafferented selectively by a unilateral dorsal rhizotomy. Control rats were sham-operated. Until 10 weeks of age, systolic tail cuff blood pressures were identical in both groups. Although from 12 weeks on systolic blood pressure was slightly (10%) but significantly lower in deafferented rats, mean arterial pressures from an indwelling catheter were identical in deafferented and control rats. We therefore conclude that a selective destruction of afferent renal nerves does not delay or prevent the development of spontaneous hypertension in rats.

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.