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Biomedical subjects

M De Paepe

Publications and source records attributed to M De Paepe.

At least 19 recordsLinked to original sources

Study of the optimum ideal protein level for weaned piglets.

The amount of ideal protein, represented by the first limiting valine (Val), for optimising the growth performances of weaned hybrid piglets was studied. Feeds were formulated based on the ideal protein concept and on a constant essential/nonessential amino acid (AA) ratio and net energy (NE) level. The animal performance trial was composed of five dietary treatments ranging from 0.57 to 0.81% calculated apparent (app.) ileal (il.) digestible (dig.) Val. The piglets, male and female in equal numbers (11 replicates x 6 piglets/pen x 5 treatments) entered the trial at about 4 weeks old (average live weight 8.1 kg). The piglets were a cross product of Piétrain sire x hybrid dam. Feed intake and weight were recorded every two weeks until the end of the trial at 10 weeks of age (average live weight 20.6 kg). The requirement was expressed in st. il. dig. AA-units, as this unit approaches available AA better than app. il. dig. AA. The standardised (st.) il. AA digestibility coefficients (DCAA) were determined for two feeds, close to the animal performance optima, in a digestion trial with four T-cannulated piglets of approximately 6 weeks old. The feed independent endogenous nitrogen excretion was measured with a protein-free feed; although this technique underestimates the actual endogenous N-losses, it provides a reasonable estimate of basal endogenous N-losses. The determined st. il. DCAA were lower than the calculated st. il. DCAA, based on the CVB (2000); this might be linked to the higher than expected crude fibre content of the experimental feeds. The Val-requirement necessary to optimise ADG and FCR was similar and amounted 0.70% st. il. dig. Val, which corresponded with a st. il. dig. Lys-level of 1.03%.

Amino Acids, Essential↗

Genetic correction of sickle cell disease: insights using transgenic mouse models.

Sickle cell disease is a hereditary disorder characterized by erythrocyte deformity due to hemoglobin polymerization. We assessed in vivo the potential curative threshold of fetal hemoglobin in the SAD transgenic mouse model of sickle cell disease using mating with mice expressing the human fetal Agamma-globin gene. With increasing levels of HbF, AgammaSAD mice showed considerable improvement in all hematologic parameters, morphopathologic features and life span/survival. We established the direct therapeutic effect of fetal hemoglobin on sickle cell disease and demonstrated correction by increasing fetal hemoglobin to about 9-16% in this mouse model. This in vivo study emphasizes the potential of the SAD mouse models for quantitative analysis of gene therapy approaches.

Anemia, Sickle Cell↗

Hepatitis C virus in a hemodialysis unit: molecular evidence for nosocomial transmission.

Between February 1991 and January 1992, elevated alanine aminotransferase (ALT) levels were observed in several hemodialysis patients in a dialysis center in Dendermonde, Belgium. By the end of 1992, 25 out of 68 patients had seroconverted for HCV antibodies. The HCV strains from 23 of these seroconverters were genotyped and classified as genotype 1b. Sequence analysis of the HCV Core region was carried out in 12 patients, 9 of whom were infected with a strain bearing a unique sequence motif as compared with the currently known HCV 1b strains. A new 5' UR/Core line probe assay was designed to screen for such variations. Twenty patients tested positively for this special sequence motif, while the other 3 showed the regular subtype 1b sequence. Phylogenetic analysis of the Core sequences further revealed that the latter three were neither related to the main special strain of the infection, nor to each other. These three strains could be traced to two patients already infected at the time of residence in other dialysis units and to one patient who already showed ALT elevations in 1989. Epidemiological studies revealed no traceable source for this outbreak. In conclusion, molecular analysis demonstrates nosocomial transmissions by a peculiar genotype 1b strain in a dialysis center. Three other genotype 1b strains were also present in the unit, but were not responsible for the outbreak.

Alanine Transaminase↗

Long-term metabolic control by rat islet grafts depends on the composition of the implant.

This study examines whether the loss of metabolic control in initially normalized islet transplants can result from the inadequate composition of the donor tissue. Streptozotocin-induced diabetic rats were followed for 64 weeks after the intraportal injection of islet isografts with different composition. The implantation of 2.3 million beta-cells (10(7)/kg body wt) as particles (>100 microm diameter) of primarily insulin-positive (70%) and glucagon-positive (20%) cells succeeded in a long-term normalization of 2-h fasting glycemia, glucose tolerance, and serum fructosamine. The same metabolic control was achieved in animals with short and long durations of diabetes or when grafts were implanted under the kidney capsule. At posttransplantation (PT) week 64, insulin reserves were 60% lower than those in age-matched controls, which may account for the glucose intolerance in a few old recipients. The same type of graft containing 0.7 million beta-cells (4 x 10(6)/kg body wt) corrected these metabolic parameters for more than 12 weeks; the proportionally lower insulin reserves were sufficient for the long-term correction of 2-h fasting glycemia, but did not avoid glucose intolerance in older recipients. When the higher beta-cells number (10(7)/kg body wt) was injected as smaller particles (<100 mpm diameter) of lower purity (55% insulin-positive) and negligible glucagon content (<5% glucagon-positive), the metabolic parameters were also corrected for 12 weeks PT but then progressively returned to overt diabetes (6 of 10) or glucose intolerance (4 of 10). We concluded that long-term metabolic normalization can be achieved by islet implants in the liver or under the kidney capsule. The loss of metabolic control in older animals can be caused by the inadequate composition of the graft, with the number of beta-cells, the proportion of other endocrine and nonendocrine cells, and the particle size as influential variables.

Aging↗

Comparison of in situ hybridization and immunocytochemistry for the detection of residual beta cells in the pancreas of streptozotocin-treated diabetic rats.

The relative efficacy of immunocytochemistry versus in situ hybridization in identifying residual beta cells was studied in rats with streptozotocin-induced diabetes. Consecutive sections of pancreas of streptozotocin-treated diabetic rats and control animals were alternately subjected to in situ hybridization (synthetic oligonucleotides complementary to rat preproinsulin mRNA) and immunocytochemistry (monoclonal antibodies to insulin). The results obtained with both methods were quantitated with the use of computer-assisted image analysis, and the ratio of cells positive by immunocytochemistry to those positive by in situ hybridization was determined. Under normoglycaemic conditions the values obtained by immunocytochemistry correlated well with those obtained by in situ hybridization (immuno/in situ > 95%). In the streptozotocin diabetic animals, however, immunocytochemistry resulted in a distinct underestimation of the number of residual beta cells (immuno/in situ < 80%). This difference was even more striking in small islet cell clusters (< 100 microns) (immuno/in situ 20%). These results suggest that in situ hybridization for prohormone mRNA is the method of choice for the identification of residual or regenerating beta cells with very low insulin content. Caution should be used when interpreting quantitative data in diabetic conditions that are based exclusively on immunocytochemical detection methods.

Animals↗

Prevention of adoptive transfer in BB rats by prophylactic insulin treatment.

Prophylactic insulin can prevent diabetes in the BB rat. We evaluated its use to prevent adoptive transfer of diabetes by activated splenocytes. ConA-activated spleen cells from acutely diabetic BB rats were divided into two equal aliquots and injected intravenously in paired diabetes-prone BB rat littermates. At the time of cell injection, subcutaneous insulin injections (15 U.kg-1.day-1) were started in one of each pair (n = 21) of littermates, and the control littermates (n = 21) were injected with saline. The incidence of diabetes, observed 35 days after cell injection, was 95% in control rats compared with 29% in insulin-treated rats (P less than 0.05). To confirm the absence of diabetes, insulin was stopped in all nondiabetic insulin-treated rats at 63 days of age. An OGTT was performed at 65 days of age: 4 rats were glucose intolerant. All rats received comparable numbers of ConA-activated splenocytes. At the time the rats were killed, 3 insulin-treated rats had a completely normal morphology and a normal glucose tolerance. All control rats had insulitis whether they were diabetic or not. No significant difference in any mononuclear subset was observed in relation to insulin treatment. We conclude that prophylactic insulin can prevent adoptive transfer of diabetes in the BB rat without inducing changes in the mononuclear cell subsets.

Animals↗

Diagnostic criteria of analgesic nephropathy in patients with end-stage renal failure: results of the Belgian study.

Diagnostic criteria of analgesic nephropathy with well-defined sensitivity and specificity are not available. During a 2-year period all new patients (n = 273) starting renal replacement therapy in 13 Belgian dialysis units were investigated aiming to select diagnostic criteria of analgesic nephropathy with acceptable performance. Using several interview techniques, a history of analgesic abuse was found in 31% of the patients. Analgesic abusers presenting a clear non-analgesic-related renal diagnosis were excluded from analysis (n = 25). Comparing the remaining abusers (n = 60) and patients without a history of analgesic abuse (n = 188) it was found that renal imaging investigations (sonography plus tomography), showing a decrease in length combined with bumpy contours of both kidneys, presented a sensitivity of 90% and a specificity of 95%. The additional finding of signs of renal papillary necrosis resulted in an overall sensitivity of 72% and a specificity of 97%, giving a positive predictive value of 92%. Other signs frequently mentioned in the literature (hypertension, anaemia, sterile pyuria, bacteriuria, proteinuria) showed insufficient sensitivity and/or specificity to be of help for diagnosing analgesic nephropathy in end-stage renal failure (ESRF) patients starting renal replacement therapy.

Adult↗

Measurement of peritoneal lymph flow in CAPD using different osmotic agents.

No differences in lymphatic absorption ratio were observed using different osmotic agents (Glucose, Amino acid, glycorol). The differences in UF rate and intraperitoneal volumes during dialysis with these osmotic agents are soley dependent on the interactions between the osmotic agents (nature, strength) and the peritoneal membrane.

Absorption↗

[A study of the causes of staghorn calculi].

A thorough metabolic evaluation of all staghorn stone patients seems justified, considering the results obtained by the study of 27 such cases. Pak's ambulatory screening test, slightly modified, was used. This allowed the finding of a hypercalciuria in more than 50% of the cases, a hyperuricosuria in 63% of the cases and a hyperoxaluria in one case out of five. A metabolic anomaly was not detected in two patients. Although urinary tract infection, present in 75% of the cases is essential to the genesis of a staghorn stone, the question raises whether metabolic anomalies are not the primary cause of the stone formation.

Adolescent↗

Comparison of different volume markers in peritoneal dialysis.

Four peritoneal volume markers (carbon 14-labeled dextran, dextran blue, radioactive albumin, and hemoglobin) were compared. In six rabbits 14C-dextran was compared with dextran blue during a 4-hour "dwell" with a 4.25% dextrose solution. The recovery of 14C-dextran at the end of the dwell was 71% +/- 3% vs. 92% +/- 1% for dextran blue (P less than 0.001). In six other rabbits, radioactive albumin (RISA) was compared with dextran blue. The recovery of RISA was 78% +/- 4%, compared with 85% +/- 2% for dextran blue (P less than 0.05). The calculated peritoneal volumes, uncorrected for disappearance of the markers, were consistently higher than when correction was made. After correction, the calculated end volumes were similar to actually measured end volumes. In six patients with chronic ambulatory peritoneal dialysis, the intraperitoneal volume during a single dwell of 6 hours was estimated in paired observations with lactated Ringer's solution and 1.5% dextrose dialysate, using simultaneously autologous hemoglobin and RISA. In eight additional patients, a single dwell with 4.25% dextrose dialysate was studied. The recoveries of both markers were related to the osmotic strength of the dialysate. Recoveries were 66.7% +/- 2.3% and 69.6% +/- 0.9% in lactated Ringer's solution, and increased to 81% +/- 3% and 82% +/- 2% in 4.25% dextrose for hemoglobin and RISA, respectively. With each dialysate, after correction for disappearance of the marker, no differences in volume profiles or between calculated or measured end volumes could be found with either hemoglobin or RISA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Results of urometabolic evaluation in 127 patients with renal calculous disease.

One hundred twenty-seven selected stone formers were evaluated. With the simple ambulatory tests proposed by Pak for metabolic screening and a complete urologic evaluation an anomaly was found in more than 90 per cent of the cases. The patients were divided into three groups: (1) patients operated on for staghorn stones; (2) patients with episodes of spontaneous stone eliminations or young people with only one stone episode; and (3) patients operated on for stone disease. No significant differences were noted except for the occurrence of urinary tract infection and for struvite and calcium oxalate occurrence in the different groups. Urinary tract infection combined with a metabolic disorder appear to make the evolution from small kidney stone to staghorn stone a reality.

Adult↗

Mediastinal angiofollicular lymph node hyperplasia with systemic manifestations.

This case report concerns a 19-year-old girl with a mediastinal angiofollicular lymph node hyperplasia (Castleman tumour), with histological aspects of both hyalin vascular and plasma cell type. Systemic manifestations were also noticed. A lymphocytic infiltration of the bone marrow and a change in the lactic dehydrogenase iso-enzyme pattern with an increase of LDH3 were noted. After surgical removal of the mediastinal tumour complete recovery and normalisation of biological abnormalities occurred.

Adult↗

Pharmacokinetics of digoxin in C.A.P.D.

The peritoneal elimination of digoxin during C.A.P.D. was studied in five patients. The plasma half life of digoxin varied from 54 hours to 141 hours. Only 7 to 24 micrograms was eliminated via the peritoneal route during 3 to 4 days C.A.P.D. treatment. The total urinary elimination during the same period ranged from 11 to 57 micrograms. It is concluded that adjustment of dose is not necessary when starting C.A.P.D.

Aged↗

Evaluation of hemofiltration with different AN 69 membrane devices using a discontinuous flow-single needle system.

Unipuncture hemofiltration using the double headed pump (Bellco BL 760) was performed in a patient who acted as her own control for 10 sessions with a 1.0 m2 AN69 membrane (group A), 10 sessions with a 1.4 m2 AN69 membrane (group B) and 10 sessions with a 1.0 m2 AN69 membrane Filtral (group C). A two needle standard hemofiltration technique (Hemoprocessor Sartorius) was used in this patient for 10 sessions with a 1.0 m2 AN69 membrane (group D). To obtain the same amount of ultrafiltration fluid the filtration time was respectively 266, 196, 214 and 260 minutes in groups A, B, C and D.

Acrylic Resins↗

Plasma vitamin A in haemodialysis patients.

Different high performance liquid chromatographic systems were applied to the investigation of vitamin A metabolism in subjects undergoing haemodialysis. Plasma levels of retinol, retinyl esters and retinoic acid were measured. There was a significant elevation of plasma retinol and dialysis failed to normalise this level. No correlation with plasma concentrations of creatinine or urea was found. No differences in retinyl ester and retinoic acid levels were observed between healthy subjects and haemodialysis patients. These results suggest that retinol accumulation is not caused by a deficiency in its oxidative metabolism.

Adult↗

Double lumen needle in unipuncture dialysis type double headpump.

Single needle dialysis is used as a method of vascular access in many European dialysis centres. However, recirculation has been incriminated as a disadvantage of this procedure. According to in vitro studies, recirculation should be limited to a minimum when using double lumen needles. The present study makes an in vitro comparison between single and double lumen needles in unipuncture (single needle) dialysis of the type double headpump (Bellco, BL 760) and studies the role of recirculation in dialysis performance. Although recirculation is significantly reduced with the double lumen needle, compared to the single lumen needle, the clearance of small molecules is not significantly different for both needle types.

Adult↗