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Biomedical subjects

P Willemsen

Publications and source records attributed to P Willemsen.

18 recordsLinked to original sources
PubMed2002

Skeletal muscle metastasis from a conventional renal cell carcinoma, two years after nephrectomy: a case report.

In this paper, we describe a case of skeletal muscle metastasis from a conventional (clear cell) renal cell carcinoma, two years after nephrectomy. Our first clinical tentative diagnosis was soft tissue tumour, showing the mimicking capacity of renal cell carcinoma. A review of literature shows that skeletal muscle metastases from renal cell carcinoma are extremely rare: only 16 cases have been described. In 5/16, the muscle mass was the initial manifestation of the renal tumour. In the other 11/16, the muscle masses were metachronous (10 months-16 years). We conclude that, when confronted with a patient with a muscle mass and a history of renal cell carcinoma, one should always keep in mind the possibility of a (late) renal cell carcinoma metastasis.

Aged↗
PubMed2002

Osteomyelitis pubis versus osteitis pubis: a case presentation and review of the literature.

An athletic 23 year old man presented with suprapubic tenderness, fever, and raised inflammatory blood variables. A diagnostic laparoscopy was performed, with a presumed diagnosis of retrocaecal appendicitis, but no abnormalities were found, apart from free fluid in the pouch of Douglas. Imaging of the pubic area suggested bony infection and inflammation. Biopsy and culture confirmed the presence of Staphylococcus aureus, a very common pathogen. The final diagnosis was osteomyelitis pubis, an infectious disease, and osteitis pubis, an inflammatory disease.

Adult↗
PubMed1999

Laparoscopic management of acute small bowel obstruction.

Laparosopy is now a well established tool in abdominal surgery. More often it is used in acute abominal situations. We present our experience with laparoscopy and laparoscopic treatment in patients with acute small bowel obstruction. Although it is technically challenging, in carefully selected patients laparoscopy and laparoscopic treatment is feasible and a valid option for treatment.

Adult↗
PubMed1997

Characterization of the IGF system and analysis of the possible molecular mechanisms leading to IGF-II overexpression in a mesothelioma.

The expression of members of the IGF system in a mesothelioma from a patient suffering from hypoglycemia, in term placenta and HT29 colon adenocarcinoma cells were compared. Very high levels of IGF-II mRNA and protein were detected in the mesothelioma. Moreover, half of the IGF-II protein took the high-molecular-weight form. We also analyzed the parental imprinting status and the promoter usage of the IGF-II gene. Our results showed loss of imprinting (LOI) in the mesothelioma while the imprinting was maintained in HT29 cells, expressing moderate levels of the transcript. Promoter P4 was active in the three tissues we analyzed, whereas IGF-II mRNA transcription from promoter P3 was only detected in the mesothelioma and the placenta, expressing comparably high levels of the transcript. IGF-II gene structure was identical in the analyzed tissues and cells. The type-I receptor mRNA expression was very low in the tumor. IGFBP-2, -4 and -5 mRNAs were detected in the mesothelioma, while IGFBP-2, -3 and -5 transcripts were detected in the placenta. IGFBP-1 and -6 transcripts were not detected.

Aged↗
PubMed1996

Purification and properties of an enzyme involved in the ATP-dependent activation of the methanol:2-mercaptoethanesulfonic acid methyltransferase reaction in Methanosarcina barkeri.

In Methanosarcina barkeri the transfer of the methyl group from methanol to 2-mercaptoethanesulfonic acid is catalyzed by the concerted action of two methyltransferases. The first one is the corrinoid-containing methanol:5-hydroxybenzimidazolylcobamide methyltransferase (MT1), which binds the methyl group of methanol to its corrinoid prosthetic group. MT1 is only catalytically active when the cobalt atom of the corrinoid is present in the highly reduced Co(I) state. In the course of its purification and even during catalysis, MT1 becomes oxidatively inactivated. The enzyme, however, may be reductively reactivated by a suitable reducing system (hydrogen and hydrogenase), ATP, and an enzyme called methyltransferase activation protein (MAP). In order to elucidate its role in the reactivation process, MAP was purified to apparent homogeneity. The protein had an Mr = 60,000. Preincubation of the enzymic components involved with 8-azido-ATP or with ATP demonstrated MAP to be the primary site of action of ATP. In agreement herewith, the protein was autophosphorylated by [gamma-32P]ATP in a 1:1 stoichiometry. Phosphorylated MAP substituted for ATP in the activation of MT1, and the addition of increasing amounts of MAP phosphate resulted in a corresponding increase of active MT1. However, in the presence of limiting amounts of MAP, maximal activation of MT1 could be achieved during a lag phase provided ATP was present, indicating that MAP acts as a catalyst. This paper is the first to report on the presence, isolation, and function of a phosphorylated protein in a methanogenic archaeon.

Adenosine Diphosphate↗
PubMed1996

Dysrhythymia from an intrapericardial air gun pellet: a case report.

We report a case of penetrating intrapericardial injury caused by an air gun pellet in which the onset of dysrhythmia suggested that the pericardium had been breached. Electrocardiographic changes appeared to be more useful in diagnosing pericardial penetration than transthoracic echocardiogram in this case.

Adolescent↗
PubMed1990

Receptor-active glycolipids of epithelial cells of the small intestine of young and adult pigs in relation to susceptibility to infection with Escherichia coli K99.

Glycolipids from mucosa scrapings of small intestine of neonatal and adult pigs were tested by the thin-layer chromatogram overlay assay for the binding of Escherichia coli K99. There was practically no binding to acid or non-acid glycolipids of adult pig, known to be resistant to infection with this bacterium. However, piglets, which are susceptible to infection, showed a clear binding to a doublet band in the acid glycolipid fraction. The receptor-active glycolipid was isolated and shown by mass spectrometry, NMR spectroscopy and degradation methods to be NeuGc alpha-3Gal beta 4Glc beta Cer (NeuGc-GM3), the two bands being due to heterogeneity of the ceramide. When tested against various reference glycolipids, NeuAc-GM3 was shown to be inactive. This ganglioside was dominating in adult pig. The apparent developmental disappearance of N-glycolyl groups in glycolipids of intestinal mucosa may have a correspondence in protein-linked sequences as well as thus explain the resistance of adult pigs to infection with E. coli K99.

Aging↗
PubMed1990

Changes in myocardial high-energy phosphate stores and carbohydrate metabolism during intermittent aortic crossclamping in dogs on cardiopulmonary bypass at 34 degrees and 25 degrees C.

The effect of cooling to 25 degrees C on myocardial metabolism was studied during four periods of global ischemia (10 minutes each) followed by 15 minutes of reperfusion in dogs on cardiopulmonary bypass. Systemic and heart temperature at normothermia (group N, 34 degrees C; n = 15) was compared with general hypothermia (group H, 25 degrees C; n = 16). Before and at the end of each aortic crossclamp period in small myocardial biopsy specimens the adenosine triphosphate, creatine phosphate, inorganic phosphate, glycogen, and lactate content was analyzed. Also, lactate and inorganic phosphate were measured in the coronary effluents during the repetitive periods of reperfusion. Hemodynamic function was not different at 60 minutes after cardiopulmonary bypass compared with pre-cardiopulmonary bypass values, and was not different between the groups N and H. The tissue content of adenosine triphosphate and glycogen decreased progressively during the experimental period, resulting in slightly depressed values in both groups at the end of cardiopulmonary bypass. Pronounced effects of ischemia and reperfusion on tissue content of creatine phosphate, inorganic phosphate, and lactate were observed after each period of ischemia. The net decrease in tissue creatine phosphate content was not different between groups N and H (41 +/- 4 versus 38 +/- 4 mumol.gm-1 dry weight; mean +/- standard error of the mean) after 10 minutes of ischemia. However, during ischemia the net inorganic phosphate increase in myocardial tissue was significantly higher in group H (70 +/- 7 mumol.gm-1) than in group N (44 +/- 3 mumol.gm-1). These findings do not support the notion that myocardial protection is improved during hypothermia. Moreover, quantitatively the release of inorganic phosphate and lactate did not correlate with the amount accumulated in the myocardial tissue during the preceding periods of ischemia. The release appeared to be temperature dependent, that is, significantly reduced at 25 degrees C. The present data demonstrate why clinical outcome is satisfactory in both surgical procedures, when in general the periods of aortic crossclamping do not exceed 10 minutes each and the reperfusion periods in between the ischemic episodes last about 15 minutes. Besides, the findings indicate that hypothermia is not strictly necessary under these circumstances.

Adenosine Triphosphate↗
PubMed1989

Metabolic and haemodynamic changes in the heart during the early phase of cardiopulmonary bypass: II. Animal experiments.

A significant release of lactate instead of uptake was observed during the first 10 min of cardiopulmonary bypass preceding aorto-coronary bypass surgery in human patients. To clarify these findings in more detail, myocardial lactate and oxygen metabolism was studied in healthy dog hearts subjected to a protocol similar to the clinical situation. In one group (n = 11) normothermia at 34 degrees C was used with an empty beating heart, and in the other group (n = 11) hypothermia with ventricular fibrillation was applied. Within the first 10 min of bypass no significant changes in high energy phosphates were observed in myocardial biopsies. However, a marked decrease in mean aortic blood pressure and a simultaneous lowering in oxygen consumption was observed in both groups after instalment of bypass. An initial shift from lactate uptake to lactate release occurred while on bypass in the normothermia group. After 10 min of bypass, lactate uptake was restored in hearts of both groups. Therefore, the lactate release during the initial phase of bypass in patients originates both from the instalment of the bypass and from (local) inadequate perfusion, which is most likely to be due to stenosed coronary arteries.

Animals↗
PubMed1988

The myocardial content of fatty acids and phospholipids during the calcium paradox.

Readmission of Ca2+ after a short period of Ca2+-free perfusion results in a rapid and massive release of cytoplasmic proteins from the heart (calcium paradox). Maximal release rates of proteins are already reached within 2 min after Ca2+ repletion. The precise mechanism underlying the loss of cellular membrane integrity, resulting in the loss of intracellular proteins, has not been clearly defined. The present study indicates that neither substantial degradation of phospholipids, being important constituents of myocardial membranes, nor accumulation of fatty acids occur during the early phase (within 1.5 min) of Ca2+ readmission. Thereafter significant amounts of such fatty acids as arachidonic acid accumulate in the Ca2+ repleted hearts. The late onset of arachidonic acid accumulation, most likely reflecting phospholipid degradation, is considered to be an epiphenomenon occurring in myocardial cells which became heavily damaged, as indicated by the substantial loss of lactate dehydrogenase, during the early phase of Ca2+ repletion. Interestingly, tissue fatty acid levels increased already significantly during the Ca2+-free perfusion period (by about 240%). The significance of this finding is not completely understood. A possible causal relationship with disturbed ion homeostasis during the induction of calcium paradox remains to be established.

Animals↗
PubMedDate not supplied

A defunctioning stoma in the treatment of lower third rectal carcinoma.

INTRODUCTION: Total mesorectal excision (TME) is the accepted standard for rectal cancer treatment. However, there is an increased risk of symptomatic anastomotic leakage associated with TME as TME potentially endangers the blood supply of the remaining rectum. On top of this, many patients will receive neo-adjuvant radio-chemotherapy. A defunctioning stoma helps in avoiding severe complications of anastomotic failure. MATERIAL AND METHODS: We prospectively collected data of all patients with a rectal carcinoma within reach of the palpating finger, operated on in our department between December 2000 and January 2005. There were 70 patients (42 men and 28 women, median age 70 (range 32-95)). RESULTS: In 40 patients (40/70 = 57%) a sphincter-saving procedure was performed. Eleven patients were diagnosed with anastomotic leakage or failure. Seven patients had neo-adjuvant radio-chemotherapy, 4 had no neo-adjuvant therapy. In 4 patients signs of anastomotic leakage were seen on the barium-enema that is routinely performed before closing the defunctioning stoma. Seven patients (7/40 = 17,5%) had clinical signs of anastomotic leakage. Three of them could be treated conservatively with antibiotics and parenteral nutrition. Two of these patients did not have a defunctioning stoma. Four patients needed re-intervention and were treated in intensive care for several days. Three of these patients did not have a defunctioning stoma. CONCLUSION: Neo-adjuvant radio-chemotherapy and TME resection are two factors in the treatment of rectal cancer that might interfere with anastomotic healing in the case of a sphincter-saving procedure. The construction of a defunctioning stoma helps in limiting the complications of anastomotic leakage or failure.

Adult↗
PubMedDate not supplied

Frozen section in thyroid surgery.

OBJECTIVE: We studied the use of frozen section in the detection of malignancy in thyroid surgery in a large teaching hospital. MATERIALS AND METHODS: We reviewed all case notes of patients operated on for thyroid disease between January 1st 1997 and December 31st 2004. We identified 420 operations in 408 patients. Data were available for 417 operations. RESULTS: In patients with a solitary thyroid nodule, a frozen section is sometimes performed. Frozen section was done in 128 of 417 operations. The specificity for malignancy was 98.16%. The positive predictive value was 81.81% and the negative predictive value 93.85%. However the sensitivity was 56.25%. Frozen section is a time-consuming investigation. With follicular lesions it is very difficult to distinguish between benign disease and malignancy since the diagnosis of malignancy depends on capsular and/or blood vessel invasion. Also it costs about 100 Euro (approximately 125 dollars). CONCLUSION: This study confirms that adequate histopathologic diagnosis of thyroid disease is based on extensive subsampling of the specimen which is not possible during a peroperatory frozen section procedure.

Adolescent↗
PubMedDate not supplied

[Paraduodenal hernia: an unusual cause of intestinal obstruction].

Paraduodenal hernia. The paraduodenal hernia is the most common type of intraabdominal hernia. There exists a right and left variety, both of them with their own specific pathogenesis. The clinical manifestations range from intermittent and mild digestive problems to acute intestinal obstruction. An exact preoperative diagnosis is seldom made. The knowledge of their pathogenesis and the anatomical characteristics is very important for a successful surgical treatment.

Adult↗