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Biomedical subjects

Y Ingenbleek

Publications and source records attributed to Y Ingenbleek.

At least 37 records · Page 2Linked to original sources
PubMed1979

Hormonal and nutritional status: critical conditions for endemic goiter epidemiology?

Recent advances in protein metabolism and in glycoprotein synthesis bring further insight into endemic goiter epidemiology. Retinol circulates in the blood stream in close parallelism with retinol-binding protein and prealbumin (RBP-PA), a protein complex whose liver secretory rate is dependent upon hormonal and nutritional status. On the other hand, normal glycosylation reaction occurs through the formation of a retinol-linked sugar complex. It is suggested that the relative drop of serum retinol levels, as a result of modified hormonal climate and/or declining protein status, might constitute a critical factor capable of inducing a defective incorporation of mannose into native thyroglobulin, leading to an early depression of the full glycoprotein production. This concept affords a comprehensive explanation of the following unresolved data recorded in goitrous areas: (1) clinical and biochemical discrepancies between subjects living in the same morbid territory, (2) persistence of endemicity in spite of appropriate iodine supplementation, (3) similar prevalence of goiter hypertrophy in male and female prepubertal children, (4) increased frequency of goiter enlargement in the four most vulnerable groups, namely preschool children of both sexes, adolescent girls, pregnant women, and elderly persons, (5) decreased impact of thyroid swelling accompanying improved socio-economic status, even without iodine addition, and (6) resurgence of goitrous hyperplasia as an effect of seasonal or sporadic deterioration of nutritional habits, even when iodine supply remains unchanged.

Adolescent↗
PubMed1978

Thyroid iodide clearance and radioiodide uptake in protein-calorie malnutrition.

The thyroid function was evaluated in two comparable groups of 12 protein-calorie malnourished children respectively by oral and intravenous test using radioiodine 131I. Maximal radioiodide uptake (RAIUmax) peaked within 24 hr in the intravenously investigated children, but only after 48 hr in the orally investigated children. In both protein-calorie malnutrition groups, the mean RAIUmax was significantly decreased by comparison with the mean normal RAIUmax (P less than 0.01). In protein-calorie malnutrition children, the RAIU curve reached intermediate values ranging from subnormal to about nearly half the normal. Thyroid clearance was early depressed and in some cases, dropped to values as low as one tenth of the normal mean (P less than 0.001), reflecting a severe thyroid involution. There is a high correlation between the RAIUmax and thyroid clearance values (r = 0.95); the regression line is defined by the equation Y = 1.12X + 17.08. Both functional parameters of thyroid activity appear to be mainly lowered in relation to the duration of protein deficiency.

Child, Preschool↗
PubMed1978

[Thyroid function in protein-caloric malnutrition in infants (author's transl)].

Iodine kinetics and thyroid function were investigated in 68 cases of protein-caloric malnutrition (senegales children). This nutritional state induces an acute and severe alteration of thyroid function, as indicated by the reduced iodine uptake and clearance, a 50% decrease of hormonal secretion rate, and the low levels of total and free T4. T3 concentration is also very low: this may be partly due to a defective conversion of T4 to T3. Despite this state of primary hypothyroidism, no hypersecretion of TSH is observed.

Age Factors↗
PubMed1976

T3 resin uptake in protein-calorie malnutrition.

RT3U3) is significantly elevated (P less than 0.001) in the acute stage of kwashiorkor and returns to normal after 2 weeks of appropriate refeeding. RT3U is characterized by a high negative correlation with TBGcap. This negative correlation is maximal on admission (r equals -0.88) and gradually declines to normal value (r equals -0.63) with clinical recovery. This finding is consistent with the main role attributed to TBG in determining RT3U level. The collected data emphize the importance of the protein plasma levels in the evaluation of the thyroid function with RT3U in protein-calorie malnutrition.

Child, Preschool↗
PubMed1975

Triiodothyronine and thyroid-stimulating hormone in protein-calorie malnutrition in infants.

Protein-calorie malnutrition (P.C.M.) in a group of 43 Senegalese children aged eighteen to thirty months was characterised by a sharp fall in serum-triiodothyronine (T3) concentration to 25-3% of the mean value in healthy age-matched controls. This decrease in T3 was significantly (P less than 0-001) more pronounced in kwashiorkor of recent onset than in long-term P.C.M., a finding which suggests that impaired thyroxine (T4) monodeiodination in the liver was responsible for the fall in serum-T3 concentration rather than a reduction in the secretion of T3 by the thyroid. Serum-T3 concentrations became normal in both malnourished groups after two weeks of appropriate nutrition. Serum-T3 concentrations in healthy, euthyroid, Senegalese children were higher than in White children. In frank kwashiorkor in Senegalese children, serum-thyroid-stimulating-hormone (T.S.H.) concentrations were within the normal range throughout the entire course of dietary therapy, indicating that the children remained euthyroid. In contrast, protracted P.C.M. led to impairment of the T.S.H./T3 feedback mechanism and to a condition resembling hypophysectomy, which required two weeks' dietary therapy for its correction.

Body Height↗
PubMed1975

Albumin, transferrin and the thyroxine-binding prealbumin/retinol-binding protein (TBPA-RBP) complex in assessment of malnutrition.

A comparative study of the level of 4 plasma proteins in malnutrition shows that albumin has low sensitivity, transferrin has intermediate and the TBPA-RBP complex has the highes sensitivity to an alteration in the nutritional status. According to protein and/or iron deficiency, the synthesis of trnasferrin seems to be submitted to contradictory impulses which partially invalidates this test as a reliable index for estimating protein depletion alone. On the contrary, the components of the TBPA-RBP complex respond together and in a parallel direction to protein deficiency. The high degree of sensitivity of TBPA and RBP to an inadequate protein intake is apparently related to their rapid turnover rate and to their unusual richness in tryptophan, which is known to play a key role in the control of protein synthesis. Measurement of TBPA (or RBP) is proposed as a method for the detection of pre-kwashiorkor and early marasmus.

Child, Preschool↗
PubMed1975

The role of retinol-binding protein in protein-calorie malnutrition.

Plasma RBP is decreased to 1.62 mg plus or minus 0.71/100 ml, or 31.1 percent of normal, in the acute stage of kwashiorkor. RBP doubles its plasma level after 1 wk and triples after 2 wk of appropriate refeeding. The return to normal of RPB runs in close parallel with prealbumin (PA), implying that both components remain bound by 1:1 molar ratio in the PA-RBP complex. Low values recorded on admission for RBP seem to be the result of reduced liver biosynthesis. On the other hand, a high correlation persists between RBP and retinol plasma level along the successive steps of clinical recovery, suggesting that RBP acts as the limiting factor for retinol transport.

Biological Transport↗
PubMed1975

Discrepancy between the measurement of thyroxine-binding prealbumin plasma level and binding capacity in protein-calorie malnutrition.

The measurement of thyroxine-bindung prealbumin (TBPA) in protein-calorie malnutrition by two different techniques leads to the recognition of an unexpected discrepancy. Whereas TBPA plasma levels as measured by immunodiffusion are markedly decreased to 29.3% of the normal, those recorded by maximal binding capacity (TBPAcap) are characterized by a wide dispersion. In the control group, the ratio between TBPAcap and TBPA plasma level is 9.1. In the malnourished group on admission, the same ratio is 30.0. The possibility of a qualitative effect in the tetrameric TBPA structure, with the binding of additional thyroxine (T4) molecules on the secondary binding sites, has been investigated. This hypothesis has been discarded by Scatchard plot studies. The normal 1:1 molar ratio between TBPA and T4 is unaffected in protein-deficient patients. Discrepant results obtained for TBPAcap and TBPA levels appear to be the consequence of low plasma protein levels, leading to an artifact in the electrophoretic method.

Blood Protein Electrophoresis↗
PubMedDate not supplied

Composition of phospholipid fatty acids in red blood cell membranes of patients in intensive care units: effects of different intakes of soybean oil, medium-chain triglycerides, and black-currant seed oil.

Fatty acid composition of phospholipids in red blood cell membranes was studied in 32 severely head-injured or cerebral stroke patients receiving enteral nutrition for 3 weeks. During this study the effects of three diets differing only by their lipid composition were investigated. The daily energy intake of each patient amounted to 2950 kilocalories, of which the lipid fraction represented 45.7%. Diet A contained only soybean oil, diet B consisted of a 50% soybean oil and 50% medium-chain triglycerides mixture, and diet C was an emulsion of 50% soybean oil, 42.5% medium-chain triglycerides, and 7.5% black-currant seed oil. Our results showed no biochemical signs of fatty acid deficiency in red blood cell membranes for the patients at the beginning of the study, after a comparison with a control group of 20 healthy adults. Inhibition of delta 6-desaturase activity on linoleic acid (C18:2 omega 6) after diet A was suggested by an increase of linoleic acid without a corresponding increase of dihomo-gamma-linolenic acid (C20:3 omega 6). Replacing 50% of soybean oil by with medium-chain triglycerides (diet B) prevented this enzyme inhibition. Supply of black-currant seed oil rich in gamma-linolenic (C18:3 omega 6) and stearidonic (C18:4 omega 3) acids (diet C) induced significant increases of dihomo-gamma-linolenic and eicosapentaenoic (C20:5 omega 3) acids, without influencing arachidonic acid (C20:4 omega 6) levels. This balance was evaluated through the ratio (C20:3 omega 6 + C20:5 omega 3)/C20:4 omega 6.

8,11,14-Eicosatrienoic Acid↗