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Biomedical subjects

M F Von Meyenfeldt

Publications and source records attributed to M F Von Meyenfeldt.

14 recordsLinked to original sources
PubMed2004

A needle-localised open-breast biopsy for nonpalpable breast lesions should not be performed for diagnosis.

BACKGROUND: The achievement of tumour-free margins on excision of nonpalpable breast lesions that have aroused only an intermediate or low level of suspicion before surgery and do turn out to be malignant is a challenge for the surgeon. The purpose of this study was to determine factors that influence the probability of obtaining tumour-free margins after needle-localised excision of a nonpalpable breast carcinoma. METHOD: During a 10-year period all needle-localised breast biopsies (NLBB) carried out in the Department of Surgery were retrospectively analysed. Possible influential factors considered included: age of the patient, year of NLBB, appearance of the lesion on imaging, preoperative diagnostic index, method of localisation, surgeon's level of experience, specimen size and radiology of the specimen, and all these were analysed in a multivariate logistic regression analysis. RESULTS: In all, 400 needle-localised breast biopsies had been performed. Excision with tumour-free margins was more often achieved, and the final intervention less often took the form of a mastectomy, when the lesion was classified preoperatively as malignant (P = 0.02). CONCLUSION: The outcome of treatment of a needle-localised breast cancer excision is better when the breast lesion is known to be malignant before surgery.

Adult↗
PubMed2003

Effect of a protein and energy dense N-3 fatty acid enriched oral supplement on loss of weight and lean tissue in cancer cachexia: a randomised double blind trial.

AIM: N-3 fatty acids, especially eicosapentaenoic acid (EPA), may possess anticachectic properties. This trial compared a protein and energy dense supplement enriched with n-3 fatty acids and antioxidants (experimental: E) with an isocaloric isonitrogenous control supplement (C) for their effects on weight, lean body mass (LBM), dietary intake, and quality of life in cachectic patients with advanced pancreatic cancer. METHODS: A total of 200 patients (95 E; 105 C) were randomised to consume two cans/day of the E or C supplement (480 ml, 620 kcal, 32 g protein +/- 2.2 g EPA) for eight weeks in a multicentre, randomised, double blind trial. RESULTS: At enrolment, patients' mean rate of weight loss was 3.3 kg/month. Intake of the supplements (E or C) was below the recommended dose (2 cans/day) and averaged 1.4 cans/day. Over eight weeks, patients in both groups stopped losing weight (delta weight E: -0.25 kg/month versus C: -0.37 kg/month; p = 0.74) and LBM (Delta LBM E: +0.27 kg/month versus C: +0.12 kg/month; p = 0.88) to an equal degree (change from baseline E and C, p<0.001). In view of evident non-compliance in both E and C groups, correlation analyses were undertaken to examine for potential dose-response relationships. E patients demonstrated significant correlations between their supplement intake and weight gain (r = 0.50, p<0.001) and increase in LBM (r = 0.33, p = 0.036). Such correlations were not statistically significant in C patients. The relationship of supplement intake with change in LBM was significantly different between E and C patients (p = 0.043). Increased plasma EPA levels in the E group were associated with weight and LBM gain (r = 0.50, p<0.001; r = 0.51, p = 0.001). Weight gain was associated with improved quality of life (p<0.01) only in the E group. CONCLUSION: Intention to treat group comparisons indicated that at the mean dose taken, enrichment with n-3 fatty acids did not provide a therapeutic advantage and that both supplements were equally effective in arresting weight loss. Post hoc dose-response analysis suggests that if taken in sufficient quantity, only the n-3 fatty acid enriched energy and protein dense supplement results in net gain of weight, lean tissue, and improved quality of life. Further trials are required to examine the potential role of n-3 enriched supplements in the treatment of cancer cachexia.

Aged↗
PubMed2003

Interexamination variation of whole breast ultrasound.

The purpose of this study was to determine the interexamination agreement of ultrasound of the breasts. This includes the complete process of performing whole breast ultrasound and interpreting the dynamic scanning and the static images by one person. In a prospective study, 58 patients with a clinical indication for mammography underwent an ultrasound examination of both breasts by three independent sonographers. The sonographers had full knowledge of the physical and mammographic findings. Histology and 12 month follow-up were used as the reference standard. Interobserver variability for both mammography and breast ultrasound was measured using linearly weighted kappa statistics. Receiver operator characteristic curves were constructed to compare the diagnostic performance of the observers. The interexamination agreement for the score of the probability of malignancy after mammography was substantial (kappas ranged from 0.63 to 0.65). The interexamination agreement for the final score of the probability of malignancy after mammography and ultrasound examination was slightly better (kappas ranged from 0.72 to 0.75). The area under the receiver operating characteristic curves after mammography and ultrasound examination ranged from 0.97 to 0.98. Ultrasound examination of the whole breast shows a substantial interexamination agreement. Ultrasound examination of the breast adds consistency to mammography and physical examination.

Adolescent↗
PubMed1998

Absence of glutamine isotopic steady state: implications for the assessment of whole-body glutamine production rate.

1. During infusion of [5-15N]glutamine in patients with gastrointestinal cancer we unexpectedly observed a gradual decrease in time of the appearance rate (Ra) of glutamine in plasma. Here we investigate whether the failure to achieve a plateau isotopic enrichment in plasma is, among other factors, due to incomplete equilibration of the glutamine tracer with the large intramuscular free glutamine pool.2. Plasma and intramuscular glutamine enrichment were measured during 6-11 h infusions of L-[5-15N]glutamine and L-[1-13C]glutamine in post-absorptive patients admitted to hospital for elective abdominal surgery. L-[1-13C]Leucine and L-[ring-2H5]phenylalanine were infused to measure the proportion of glutamine appearing in plasma directly due to its release from protein.3. The glutamine tracer entered muscle, but the rise in intramuscular glutamine enrichment was small, presumably as a result of the enormous size of the intramuscular glutamine pool and the limited speed of entry of glutamine into muscle. In each patient the intramuscular glutamine enrichment was lower than that in plasma (P<0.001), and both increased with tracer infusion time (P<0.001), indicating incomplete equilibration of the glutamine tracer.4.A comparison of the results obtained by the two glutamine tracers indicated that recycling of the nitrogen label contributed to about 15% of the decrease in Ra.5. There was a gradual reduction in the glutamine release from proteolysis, which contributed to 16-21% of the decline in Ra.6. We conclude that slow equilibration of the glutamine tracer with the large muscle glutamine pool significantly contributes to the absence of isotopic steady state. Consequently, the appearance rate of glutamine in plasma measured during short tracer infusion periods (hours) considerably overestimates the whole-body glutamine flux.

Aged↗
PubMed1997

TNF-alpha has no direct in vivo metabolic effect on human muscle.

Tumor necrosis factor alpha (TNF-alpha) is thought to have a key role in metabolic changes of muscle tissue during inflammatory diseases. It is unknown whether TNF-alpha affects muscle metabolism directly or whether these changes are mediated by secondary mediators. We studied 6 patients undergoing isolated limb perfusion with TNF-alpha for irresectable soft-tissue sarcoma or in-transit melanomas. Glucose, lactate, ammonia and amino-acid consumption or production were measured in the perfusate during 3 perfusion periods: before, after TNF-alpha and after the combined administration of TNF alpha and melphalan. Arterial glucose, lactate, ammonia and amino-acid concentrations were monitored to detect metabolic effects of TNF-alpha after it entered the systemic circulation. Glucose uptake and lactate release by the limb remained unchanged after the injection of TNF-alpha alone, as well as after the combination of TNF-alpha and melphalan. Furthermore, glutamine, alanine, phenylalanine, tyrosine and total amino-acid release into the perfusate did not increase during TNF-alpha and melphalan treatment, indicating that muscle metabolism was not changed. After the isolated limb perfusion, TNF-alpha entered the systemic circulation and induced metabolic changes resulting in a doubling of arterial lactate concentrations, decreased arterial glucose concentrations and decreased arterial amino-acid concentrations. Our study shows that regional administration of TNF-alpha alone or in combination with melphalan does not directly affect muscle glucose and protein metabolism. The data suggest that systemic metabolic changes induced by TNF-alpha are mediated through secondary, centrally produced, factors.

Adolescent↗
PubMed1996

In vivo amino acid metabolism of gut and liver during short and prolonged starvation.

During starvation, splanchnic organs are proportionally more affected by protein loss than other organs. Amino acid membrane transport is one of the regulating mechanisms of protein turnover, but until now in vivo data were lacking. To study in vivo phenylalanine and tyrosine membrane transport and protein turnover in splanchnic organs, a primed continuous infusion of L-[2,6-3H]phenylalanine was given to control rats (postabsorptive) and after short (40 h) and prolonged (112 h) starvation. Data were analyzed using a three-compartment model previously used in muscle membrane transport studies. Inward and outward amino acid plasma-tissue membrane transport rates in both the liver and gut were upregulated after prolonged starvation. Metabolic shunting of phenylalanine and tyrosine increased in the gut but decreased to zero in the liver after prolonged starvation. In conjunction with this, gut and liver protein turnover increased after prolonged starvation. In the liver the net uptake of gluconeogenic precursors also increased, indicative for increased gluconeogenesis. The observed changes in amino acid metabolism in both splanchnic organs after prolonged starvation may reflect an adaptation of the gut and liver to nutritional deprivation and could be of benefit during refeeding.

Acute Disease↗
PubMed1994

Non-radical therapy for early gastric cancer.

To assess the potential benefit of R2 gastrectomy for patients with early gastric cancer, complications and long-term survival of patients who underwent conventional resection with limited lymphadenectomy (R1 gastrectomy) were analysed retrospectively. Resection margins of all 46 consecutive patients were free from tumour. Tumours were limited to the mucosa in 35 patients and infiltrated the submucosa in 11. Positive lymph nodes were found in two patients. The 30-day mortality was two patients, and cardiac and pulmonary complications occurred in five and six respectively. Anastomotic leakage developed in two patients. During 5 years of follow-up two patients died from tumour recurrence; one of these had lymph node metastases at the initial resection. Resection with limited lymphadenectomy for early gastric cancer results in a 91 per cent 5-year survival rate without the need for R2 gastrectomy with its probably higher morbidity and mortality.

Adult↗
PubMed1994

Decrease of mucosal glutamine concentration in the nutritionally depleted patient.

A diminished glutamine delivery by peripheral tissues is suggested to play an important role in the etiology of postoperative complications of nutritionally depleted patients. Decreased glutamine supply to the gut mucosa in these nutritionally depleted patients may have important consequences for the integrity of the gut mucosa barrier. To evaluate whether glutamine concentration in the gut mucosa of depleted patients is altered, patients with either a fat-free mass index below 90% or percentage ideal body weight below 90% as a result of weight loss were studied. 22 patients admitted to the University Hospital Maastricht and 14 controls were studied. After an overnight fast, venous blood was sampled and duodenal biopsies were obtained by endoscopy. Plasma and tissue amino acids were measured. Fat-free mass was determined by bioelectrical impedance measurement. In 10 depleted patients glutamine concentration in the duodenal mucosa was 2883 +/- 250 mumol/kg dry weight. Concentration of alanine was 2570 +/- 263 mumol/kg dry weight. In the non-depleted patients glutamine and alanine concentrations were respectively 3463 +/- 171 mumol/kg dry weight and 3540 +/- 315 mumol/kg dry weight. Concentrations in controls were 3296 +/- 176 mumol/kg dry weight for glutamine and 3682 +/- 372 mumol/kg dry weight for alanine. Concentrations for alanine and glutamine were significantly lower in depleted patients compared to non-depleted patients (p < 0.05). Also, alanine and glutamine concentrations were significantly correlated with percentage ideal body weight (r=0.43, p < 0.005 for glutamine and r=0.62, p < 0.001 for alanine) and fat-free mass index (r=0.42, p < 0.05 for glutamine and r=0.48, p < 0.01 for alanine) This study suggests that in patients depletion appears to be related to decreased plasma and mucosa glutamine and alanine concentrations.

Journal Article↗
PubMed1992

Perioperative nutritional support: a randomised clinical trial.

Ever since methods of artificial nutritional support became available, attempts have been made using this form of treatment to reduce mortality and morbidity in surgical patients. Many trials have addressed this question, but very few have given a meaningful answer because of conceptual and methodological flaws. We therefore undertook a prospective randomised trial investigating the effects of at least 10 days pre-operative total parenteral nutrition (TPN) (n = 51) or total enteral nutrition (TEN) (n = 50) providing 150% basal energy expenditure (BEE) non-protein energy, to reduce major postoperative complications and mortality in a homogeneous patient group with signs of depletion. 50 patients served as a depleted control group (D) and 49 patients served as a non-depleted reference group (ND) and were operated upon without delay. Depleted control patients suffered significantly more septic complications than did patients in the non-depleted reference group (p < 0.05). There was no significant difference, however, in septic complications between either of the nutritional support groups and the non-depleted control group. In high risk patients, with weight loss >10% of body weight and over 500 ml blood loss during operation, a significant decrease in major complications was observed (p < 0.05) as a result of nutritional support. We conclude that pre-operative nutritional support, in patients with severe depletion, results in a reduction in major complications to a degree that justifies its routine use in this selected group of patients.

Journal Article↗