Biomedical subjects

M Lippens

Publications and source records attributed to M Lippens.

6 recordsLinked to original sources

PubMed1999

Ideal amino acid profile and dietary lysine specification for broiler chickens of 20 to 40 days of age.

1. The aim of the study was to determine the ideal ratio of the essential amino acids lysine (Lys), methionine (Met), threonine (Thr), tryptophan (Trp), arginine (Arg), valine (Val) and isoleucine (Ile) and to assess the required dietary lysine concentration for optimum performance in broiler chickens of 2 commercial strains from 20 to 40 d of age. 2. An identical basal diet was used throughout all experiments. It consisted mainly of maize and soyabean meal and contained 172 g crude protein and 13.2 MJ AME(N) per kg. For each experiment, the basal diet was adequately supplemented with all essential amino acids except the one to be tested, which was supplemented in 6 graded concentrations in exchange for maize starch. One (Met, Trp, Arg, Val, Ile) or 2 (Lys, Thr) growth trials were conducted per amino acid tested and the response in weight gain, food: gain ratio, breast meat yield and abdominal fat were examined. 3. The ideal amino acid ratio relative to Lys (expressed as a percentage) was calculated to be 75% Met+Cys, 63% Thr, 19% Trp, 112% Arg, 71% Ile and 81% Val on a true faecal digestible basis when the data were subjected to broken-line regression analysis. From both lysine studies the concentration for optimum food: gain ratio was calculated, by exponential regression analysis, to be 11.5 g true faecal digestible lys per kg diet.

Amino Acids, Essential↗

PubMed1998

Real-life radiation burden to relatives of patients treated with iodine-131: a study in eight centres in Flanders (Belgium).

In view of the EURATOM 96/29 [1] regulations, a prospective multicentre study was performed to evaluate the present guidelines given to relatives of patients treated with iodine-131 for both thyroid carcinoma and thyrotoxicosis, based on the real-life radiation burden. This study comprised 166 measurements carried out on a group of 94 relatives of 65 patients. All relatives wore a thermoluminescent dosemeter (TLD) on the wrist for 7 days. Sixty-one relatives agreed to wear another TLD for an additional 7 days. TLD were placed on nine patients' bedside tables. The eight participating centres were arbitrarily divided into three groups according to the period of time they advised their patients to sleep separately. Groups I, II and III respectively advised their patients to sleep separately for 0, 7-10 and 14-21 days. The median dose received by in-living relatives of thyroid carcinoma patients during the 14 days following hospital discharge was 281 microSv (doses to infinity not calculated); the median dose to infinity received by in-living relatives of ambulatory treated thyrotoxicosis patients was 596 microSv, as compared with 802 microSv for in-living relatives of hospitalised thyrotoxicosis patients. In general the children of patients received a significantly (P < 0.1) lower mean dose than their partners. For thyroid carcinoma patients, only two relatives out of 19 (10%) exceeded the EURATOM 96/29 limit of 1 mSv/year. For thyrotoxic patients, 28% of relatives exceeded the EURATOM 96/29 limit, but none of them were relatives of patients who followed guidelines for 21 days. The results of this study indicate that sleeping separately for 7 days, after a period of hospitalisation of 2-3 days, will usually be sufficient for thyroid carcinoma patients. For thyrotoxicosis patients, up to 21 days of sleeping separately could be necessary in order to strictly abide by EURATOM 96/29. Therefore, the authors propose the implementation of a non-rigid dose constraint for people who "knowingly and willingly" help patients treated with 131I, while still following the ALARA principle.

Adolescent↗

PubMed1994

Computer assisted clinical data analysis.

The Diagnosis Related Groups patient classification scheme coupled with desk top PC technology permits sophisticated analysis of patient medical data. Individuals with no programming knowledge can produce sophisticated analysis. The functionality and structure of the 3M Analytical Workstation are described and example analysis reports are presented.

Computer Systems↗

PubMed1993

A comparison of iodine-123 meta-iodobenzylguanidine scintigraphy and single bone marrow aspiration biopsy in the diagnosis and follow-up of 26 children with neuroblastoma.

In staging neuroblastomas, the demonstration of tumoural invasion of the bone marrow is an important criterion with regard to the therapeutic prospects and the prognosis. Iliac crest aspiration sampling has been used routinely for the detection of bone marrow metastases in neuroblastoma. However, due to the limited character of the sampling, it sometimes leads to false-negative results. Another procedure which is used to determine the extent of neuroblastoma is metaiodobenzylguanidine (mIBG) scintigraphy. In order to establish the respective merits of both diagnostic techniques retrospectively, 148 iodine-123 mIBG scans of 26 children with neuroblastoma have been re-evaluated and compared with the results of routine bone marrow samples obtained within a 4-week period before or after scanning. Three types of mIBG uptake in the bone/bone marrow could be differentiated: (1) no visualization of the skeleton; (2) diffuse uptake in the skeleton with or without focally increased uptake, which indicates massive, diffuse bone marrow invasion by the tumour; and (3) focal tracer accumulation in one or several bones. No tracer uptake was observed in the skeleton in 91 scans. In 89 of the 91 the bone marrow biopsy was negative. Twenty-four scans showed diffuse skeletal uptake with or without foci. The bone marrow biopsies were negative for eight of those 24 scans. Hyperactive foci in one or more bones without diffuse tracer accumulation in the skeleton were detected in 33 scans. In only 7 of these 33 scans did bone marrow biopsy specimens from the iliac MDP crest contain neuroblastoma cells.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Iodobenzylguanidine↗

PubMed1993

Visualization of a parathyroid adenoma with Tc-99m MIBI in a case with iodine saturation and impaired thallium uptake.

A case of a parathyroid adenoma is presented in which the conventional Tl-201 minus Tc-99m subtraction technique failed to localize the adenoma because of prior iodide administration and a low Tl-201 uptake. Ultrasonography and CT could not provide useful data either. However, a Tc-99m methoxylisobutylisonitrile (MIBI) scintigram clearly delineated the adenoma and the thyroid tissue.

Adenoma↗

PubMed1984

The pH dependence and group modification of beta-D-xylosidase from Bacillus pumilus: evidence for sulfhydryl and histidyl groups.

The pH dependence of the kinetic parameters of beta-D-xylosidase (EC. 3.2.1.37) from Bacillus pumilus reveals that an acidic functional group with pK 8.0 is involved in the catalysis. The fast inactivation of the dimeric enzyme by near equivalent amounts of methylmethanethiolsulfonate indicates that one thiol group per monomer is essential for catalysis, consistent with previously reported results. From the reactivity of the thiol groups with respect to 5,5'-dithiobis(2-nitrobenzoic acid), the absence of subunit cooperativity was indicated. The present study also reports on the inactivation of the enzyme by diethylpyrocarbonate, and provides evidence of the importance of a histidine residue. A mechanism of catalysis is presented, in which the thiol group interacts with the substrate via partial proton transfer. The mode of participation of the histidine group is difficult to specify, but may be associated with the maintenance of the active conformation of the enzyme.

Allosteric Site↗