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Biomedical subjects

A C de Vries

Publications and source records attributed to A C de Vries.

At least 19 recordsLinked to original sources
PubMed2003

[Primary venous mesenterial thrombosis in three patients].

Three patients, a woman aged 72, a man aged 25 and a woman aged 42 years, presented at the casualty department with a subacute form of primary venous mesenterial thrombosis. As symptoms and laboratory findings are aspecific, CT scan is the gold standard for the diagnosis of this condition. In these patients no cause or predisposing factor was detected, so the disease was considered to be primary. Treatment generally consists of anticoagulant therapy and if peritonitis is present operation is indicated. Hyperdynamic circulation and inotropica are indicated after surgery and in cases of critical illness. Based on clinical findings the third patient was treated successfully with anticoagulants only. The other two also underwent partial small intestinal resection. All three patients were discharged in good health and were prescribed lifelong anticoagulants. If a cause of venous mesenterial thrombosis can be found, this must first be treated before deciding on whether lifelong treatment with anticoagulants is indicated.

Adult↗
PubMed2002

[One hundred years of the Association of Surgeons in the Netherlands. VII. Vascular surgery].

The Dutch Society for Vascular Surgery was founded in 1981, as the first daughter of the Association of Surgeons in the Netherlands. Twenty years of vascular surgery show a broad perspective. Aside from the traditional handywork--central vascular reconstruction, bypass surgery (especially in the legs), and carotid surgery--, there have been many developments. Operations are less invasive and vascular surgeons are cooperating more and more intensively with other medical disciplines, especially radiology. Examples are the endovascular treatment of abdominal aortic aneurysm, in which an endoprosthesis is inserted via minute incisions in the groin by the vascular surgeon and an (interventional) radiologist together. In addition, interventions such as percutaneous transluminal angioplasty and stenting as well as new diagnostic possibilities (e.g. MRA) strengthen the cooperation with the radiologists. The multidisciplinary approach is also extremely important in other areas. Vascular surgeons team up with internal-medicine specialists (diabetes, hypertension, lipid metabolism disorders, thrombotic syndromes, etc.), rehabilitation specialists and podotherapists (in cases of diabetic foot and amputation), vascular laboratory technicians (diagnostics and follow-up by means of doppler and duplex techniques), and neurologists (cerebrovascular diseases). In the vascular centres, patients are treated effectively by a multidisciplinary team that draws up a plan for diagnosis and treatment. The two-year postgraduate course in vascular surgery is one of the tools used to guarantee and improve the high standard of quality. To this end, cooperation within Europe in the European Society for Vascular Surgery and the development and organisation of European examinations in vascular surgery are also of the essence.

Angioplasty, Balloon↗
PubMed1998

Complications of standard elective abdominal aortic aneurysm repair.

OBJECTIVE: To evaluate complications of standard elective repair of infrarenal abdominal aortic aneurysms. DESIGN: Prospective multicentre study. MATERIALS: Two-hundred and ninety-one consecutive patients undergoing standard elective surgery for an infrarenal aortic aneurysm. METHODS: Recording adverse events according to the recommendations of the Ad Hoc Committee on Reporting Standards. RESULTS: Seventy-five patients (26%) experienced some complication following elective aortic aneurysm surgery. Twenty-two patients had a mild complication (7.6%, 95% C.I. 4.8-11.2%), 27 a moderate (9.3%, 95% C.I. 6.2-13.2%) and 26 patients had a severe and/or fatal complication (8.9%, 95% C.I. 5.9-12.8%). The in-hospital mortality was 4.1% (12 patients, 95% C.I. 2.2-7.1%). Cardiac failure was the commonest primary cause for death (58%). Twenty-two per cent of the patients had a non-fatal complication: the most frequent being pulmonary (10%) and cardiac (10%). Patients with a history of cardiac events had a five times higher risk of a fatal outcome (95% C.I. 1.1-24.0) and a two and a half times higher risk of any severe fatal or non-fatal complication (95% C.I. 1.0-6.5). Other risk factors were advancing age and the presence of pulmonary disease. CONCLUSIONS: In addition to mortality, morbidity figures of standard aneurysm operations are important, as well as associated risk factors. This is especially true when evaluating early repair of small aneurysms and new endovascular techniques.

Age Factors↗
PubMed1996

Neuromuscular disorders in patients with intermittent claudication.

OBJECTIVE: To evaluate the effect of claudication on nerve function in patients with unilateral peripheral arterial disease. DESIGN: Prospective study. SETTING: District hospital, The Netherlands. SUBJECTS: 11 Patients with unilateral intermittent claudication (diagnosed from history and ankle-brachial blood pressure index) underwent electrophysiological studies of both legs, including nerve conduction velocities, motor unit action potentials, H-reflex measurements, and muscle strength testing. The asymptomatic leg was used as the control in each case. RESULTS: Six patients had neuropathy in both the claudicating and the control leg. Three other patients had neuropathy in the claudicating leg only, which consisted mainly of disorders of nerve conduction including the H-reflex. There was no clear difference between muscle strength in the symptomatic and control legs, possibly because more than half the patients studied, had neuropathy in both legs. CONCLUSIONS: Neuropathy is common at an early stage of arterial disease and could be one of the factors leading to impaired muscle function in such patients.

Action Potentials↗
PubMed1994

Mortality rates associated with operative treatment of infrarenal abdominal aortic aneurysm in The Netherlands.

Information on surgery for non-ruptured and ruptured infrarenal abdominal aortic aneurysm (AAA) in all hospitals in The Netherlands in 1990 was obtained from the Dutch National Medical Registration Foundation. The operation rate in the population over the age of 50 years was 30.3 per 100,000 for non-ruptured AAA and 16.8 per 100,000 for ruptured aneurysm. The hospital operative mortality rate for non-ruptured AAA surgery was 6.8 per cent in 1289 patients and for ruptured aneurysm 43.6 per cent in 709. For non-ruptured AAA the mortality rate almost doubled per age group of 10 years, whereas the influence of age was less significant for ruptured lesions. The operative mortality rate for non-ruptured aneurysm in university hospitals exceeded that in other hospitals, but no difference was found for emergency surgery on ruptured AAA. Nationwide results give a more representative picture of the true mortality rate associated with operation for aortic aneurysm. Such data are important for planning future treatment strategy and for evaluating the efficacy of screening.

Adolescent↗
PubMed1993

Different effects of the hypolipidemic drugs pravastatin and lovastatin on the cholesterol biosynthesis of the human ocular lens in organ culture and on the cholesterol content of the rat lens in vivo.

This study aimed to investigate the influence of the hypocholesterolemic drugs pravastatin and lovastatin on the cholesterol biosynthesis in the ocular lens. Two model systems were used: a human lens organ culture system and an in vivo rat lens system. For measurements of cholesterol and fatty acid synthesis rates, human lenses were incubated for 20 h in the presence of [14C]acetate. Pravastatin and lovastatin were added 1 h prior to the addition of the radioactive label. In order to avoid the influence of differences relating to individual donors, one lens from each donor was incubated without drug (control) and the other lens was incubated in the presence of the drug. Statistical analysis showed that the fatty acid synthesis rate was not influenced by the drug. For each lens pair the percentage inhibition of the cholesterol synthesis caused by the drug was calculated. Using various concentrations of the drugs, a dose-response curve was composed for the inhibition of the cholesterol synthesis. The experiments showed that in the human lens organ culture system, lovastatin was 100-fold more potent than pravastatin in inhibiting the cholesterol biosynthesis. To study the in vivo influence of vastatins on the cholesterol content of the developing lens, Wistar rats were weaned at day 21 of age and subsequently the pups were fed a control diet or drug-containing diet (10, 50 or 100 mg lovastatin/kg chow) for a 3-week period. At the end of diet intervention, doses of 50 or 100 mg lovastatin/kg chow had caused a reduction of about 20% of the lenticular cholesterol content compared with controls. No effect on the lens cholesterol content by pravastatin was observed. Both human ex vivo and rat in vivo experiments show that lovastatin much more strongly inhibits the lenticular cholesterol synthesis than does pravastatin.

Adult↗
PubMed1993

Pravastatin and simvastatin differently inhibit cholesterol biosynthesis in human lens.

PURPOSE: In the current study, the hypocholesterolemic drugs pravastatin and simvastatin were compared for their influence on cholesterol biosynthesis in the human lens. METHODS: For measurements of cholesterol and fatty acid synthesis rates, human lenses were incubated for 20 hr in the presence of [14C]-acetate, and pravastatin or simvastatin. Radiolabeled [14C]-cholesterol and [14C]-fatty acids were determined. To avoid the influence of individual differences, one lens from each donor was incubated without drug (control) and the other lens was incubated in the presence of drug. For each lens pair, the percentage inhibition of the cholesterol synthesis caused by the drug was calculated. Fatty acid synthesis was not influenced by the drugs. By comparing the fatty acid synthesis rate of the drug-incubated with the control lens of a pair, a predefined exclusion criterion was used to eliminate lens pairs in which the lenses had no comparable biosynthetic capacities. RESULTS: Using various concentrations of the drugs, a dose-response curve was constructed for the inhibition of the cholesterol synthesis. The IC50 values (drug concentration give 50% inhibition) were 0.5 mumol/l and 0.004 mumol/l for pravastatin and simvastatin, respectively. 3-Hydroxy-3-methylglutaryl coenzyme A reductase activity in microsomal membranes from human lens cortex was inhibited by simvastatin and pravastatin to the same extent. CONCLUSIONS: Under the conditions used in this study, cholesterol synthesis in human lenses is inhibited by simvastatin 100-fold more effectively than by pravastatin. This difference was likely due to differences in the intracellular exposure of the reductase to the drugs in intact human lenses.

Adolescent↗
PubMed1992

[Abdominal aortic aneurysm as incidental finding in abdominal ultrasonography].

Abdominal aortic aneurysm is a life-threatening condition, which usually remains without symptoms until rupture occurs. The only way to reduce the high mortality rate (estimated at over 80%) is elective surgery on suitable patients. Therefore the presence of such an aneurysm has to be detected. For this ultrasonography is the method of choice. We studied 4399 consecutive patients aged 50 years and older, who underwent abdominal ultrasonography for the first time. According to the recommendation of the Dutch Society for Radiodiagnostics the whole abdomen was screened. In 4026 patients (1717 men and 2309 women) the ultrasound examination was performed for non-vascular reasons. In 199 of these patients (4.9%) an abdominal aortic aneurysm was an adventitious finding (133 men (7.7%) and 66 women (2.9%)). In men aged 60 years and older it was even found in 10.2%. When abdominal ultrasonography is performed for the first time in a patient aged 50 years or older, the aorta has to be screened for presence of an aneurysm.

Abdomen↗
PubMed1992

[A patient with Salmonella aortitis].

Bacterial aortitis is a rare but serious condition. Even when treated surgically, the prognosis is poor. Prompt diagnosis is mandatory. In the absence of specific clinical signs, radiological assessment by means of ultrasound and CT is most valuable. The treatment of choice is early surgical drainage, debridement and arterial reconstruction, preferably through uncontaminated tissue combined with antibiotic therapy. We report the case of a man aged 80 with Salmonella aortitis in whom the diagnosis of bacterial aortitis was made by means of ultrasound and CT, following which successful intervention was carried out.

Aged↗
PubMed1992

Eosinophilic enteritis presenting as acute abdomen: US features of two cases.

Eosinophilic enteritis is a rare disease which may mimic acute abdominal emergency. Two sonographically documented cases are presented, which were subsequently proven at operation. Although the sonographic features of severe echolucent bowel wall thickening were not specific, combination with clinical and laboratory data may suggest the correct diagnosis.

Abdomen, Acute↗
PubMed1991

Abdominal aortic aneurysm as an incidental finding in abdominal ultrasonography.

The difference between the mortality rate from ruptured abdominal aortic aneurysm (overall mortality rate 85-95 per cent and operative mortality rate 23-63 per cent), and that for elective aneurysm repair (less than 5 per cent) is dramatic. Awareness of the existence of an abdominal aortic aneurysm is therefore essential. Of 1800 consecutive patients aged greater than or equal to 50 years referred for their first abdominal ultrasonography, 113 who had been referred specifically for suspected abdominal aortic aneurysm or vascular screening were excluded. The remaining 1687 patients (693 men and 994 women) form the study group. Apart from the symptom-directed examination, the entire abdomen of every patient was routinely studied by ultrasonography. The definition of an abdominal aortic aneurysm was a local dilatation of the aorta with an anteroposterior diameter greater than 30 mm or greater than 1.5 times the anteroposterior diameter of the proximal aorta. In 82 cases (4.9 per cent) an abdominal aortic aneurysm was disclosed; 61 were in men (8.8 per cent) and 21 were in women (2.1 per cent). The prevalence of abdominal aortic aneurysm as an incidental finding in men aged greater than or equal to 60 years was 11.4 per cent. In every patient aged greater than or equal to 50 years undergoing their first abdominal ultrasonography examination, the aorta should be screened for the presence of an aneurysm.

Age Factors↗
PubMed1991

Biosynthetic capacity of the human lens upon aging.

Lipid and protein biosynthesis were investigated in organ culture of human lenses from subjects ranging from 8 to 95 years old. A marked increase of protein and cholesterol content of the human lens with age was found. No significant linear correlation of age with either cholesterol or fatty acid synthesis was observed. Moreover, there are no indications that either synthesis declines with increasing age of the subject. Notwithstanding the large variety in age of the subjects, cholesterol and fatty acid synthesis of the individual lenses were correlated with each other in a positive linear way. Non-cataractous lenses as old as 80 years revealed a normal protein synthesis pattern as determined by incorporation of [35S]methionine into protein and analysis by 2D-gel electrophoresis. In addition, they maintained a high protein biosynthetic capacity.

Acetates↗