Evaluación bioquímica del estado nutricional en un grupo de puérperas. Estudio preliminar / Biochemical evaluation of nutritional status in a group of puerperal women. Preliminary study

Se determinaron los niveles de proteína transportadora de vitamina A, transtirretina (prealbúmina), transferrina, inmunoglobulina A, fracción C3 de complemento en suero y de inmunoglobulina A total en saliva, en un grupo de 109 mujeres durante los primeros días post-parto. Las muestras de sangre y saliva no estimulada de las pacientes en ayunas se mantuvieron a -20 ºC hasta ser analizadas por inmunodifusión radial en placas de agarosa. Los resultados (media ± DE), expresados como porcentaje de las proteínas totales, fueron: 0,06 ± 0,02; 0,24 ± 0,06; 6,36 ± 1,19; 2,70 ± 0,47 y 3,76 ± 1,17 para proteína transportadora

Effect of Newcastle disease virus infection on vitamin A metabolism in chickens.

The effect of Newcastle disease virus (NDV, La Sota strain) infection on vitamin A metabolism was investigated in chickens maintained on normal or marginal vitamin A intake. NDV, a virus of the Paramyxoviridae family that primarily affects epithelial tissue, was administered at 4 wk of age. Plasma levels of retinol, retinol-binding protein and, to a lesser extent, transthyretin were found to be significantly lower during both the acute and postacute phases of infection in chickens fed a diet marginally deficient in vitamin A compared to noninfected birds fed the same diet, while vitamin A content in liver was unaffected. However, in chickens fed adequate vitamin A, NDV infection did not influence the parameters measured. Levels of retinol-binding protein in liver were significantly increased by inadequate vitamin A nutriture, but infection partly reduced this increase. The results suggest that the reduced vitamin A status in marginally vitamin A-deficient chickens infected with NDV can be attributed to a combination of a direct effect of the virus on retinol-binding protein metabolism in liver and an increased rate of utilization and catabolism of retinol and retinol-binding protein by extrahepatic tissues.

Fluorescent derivative of cysteine-10 reveals thyroxine-dependent conformational modifications in human serum prealbumin.

Fluorescence studies on the N-(iodoacetyl)-N'-(5-sulfo-1-naphthyl)ethylenediamine-labeled cysteine-10 residue of human prealbumin were carried out to detect conformational changes induced by the binding of the ligand thyroxine to the two structurally identical binding sites. A red shift of the spectrum was observed and the total change was confined to the first ligand. This was interpreted as resulting from a conformational change which increases the exposure of the fluorescent probe moiety. Thyroxine also alters the effect of the collisional quencher, acrylamide, confirming the greater exposure of the probe. This modification in structure is associated with changes in relaxation time which indicate that when thyroxine is bound there is an increase in the rotational freedom of the segment or domain of prealbumin which contains the fluorescent probe.

TSF, RBP and TBPA as nutritional indices in surgical patients with gynecological cancer.

The Authors investigated the usefulness of some biochemical markers of visceral protein synthesis (TSF, TBPA and RBP) in 24 patients affected with gynecological cancer and treated with Total Parenteral Nutrition in the perioperative period. The absence of an improving TSF and TBPA is related to increased morbidity and mortality.

Assessment of vitamin A status in an elderly French population using impression cytology with transfer.

The vitamin A status of 105 elderly French people was assessed by ocular impression cytology with transfer (ICT). 5 patients (4.8%) had a negative ICT defined by the absence of goblet cells and the enlargement of the epithelial cells (deficient vitamin A status). 100 patients had a positive ICT with goblet cells and small, numerous epithelial cells (sufficient vitamin A status). ICT results were compared to serum biochemical parameters. Mean serum levels of retinol, retinol-binding protein (RBP) and transthyretin (TTR) were significantly lower while C-reactive protein (CRP) and orosomucoid were significantly higher in negative ICT than in positive one. The etiology of vitamin A deficiency is difficult to conclude (malnutrition, vitamin A deficiency, inflammation). ICT is a good indicator of peripheral vitamin A deficiency in our experience.

Vitamin A treatment of sexual dysfunction in male alcoholics.

Thirty abstinent male alcoholics with sexual dysfunction were randomized to treatment with 3 mg RE (10,000 IU) vitamin A or placebo daily for 4 mo. Age, drinking history, period of abstinence before enrollment, and base-line laboratory indices were comparable in both groups at entry. Of the 15 subjects given placebo, 13 had a partial or full recovery of sexual functioning. By contrast, of those given vitamin A, 10 had a partial response. There were no complete responders. Six subjects (1 placebo, 5 vitamin A) who developed liver abnormalities during treatment underwent liver biopsies; five had fibrosis or cirrhosis. A significant decrease in luteinizing hormone was noted in the group given vitamin A compared with the placebo-treated group. Thus vitamin A therapy did not improve sexual functioning in male alcoholics and may have been associated with toxicity.

Reduced prealbumin (transthyretin) in CSF of severely demented patients with Alzheimer's disease.

Prealbumin (transthyretin) quantified in CSF was negatively correlated with degree of dementia in 24 patients with dementia of Alzheimer type (DAT). There was neither a significant correlation between prealbumin in serum and degree of dementia nor between prealbumin in CSF and number of T lymphocytes in serum. There was no such relationship in 7 patients with multi-infarct dementia. Prealbumin was also quantified in 4 non-demented control groups, one consisting of 14 age- and sex-matched neurological patients, 17 with MS, 6 with ALS and 10 patients who had had a subarachnoid hemorrhage. Prealbumin was significantly lower in the last group. The study suggests that there may be a relationship between prealbumin levels in cerebrospinal fluid and degree of dementia. It is suggested that this may be caused by affection of the choroid plexus.

Nutritional status of patients with acquired immunodeficiency syndrome.

Nutritional status may be an important factor in the prognosis of morbidity and mortality. We assessed the nutritional status of individuals seropositive for human immunodeficiency virus (HIV) (as confirmed by Western blot) and of patients with AIDS, by determining the concentration in serum of total protein, albumin, prealbumin (transthyretin), and retinol-binding protein. HIV-seropositive individuals showed no significant difference from normal volunteers in values for prealbumin, albumin, and retinol-binding protein. Patients with AIDS showed significantly smaller prealbumin and albumin concentrations than did normal and HIV-positive individuals. There was no significant difference in the concentration of retinol-binding protein among the three groups. The concentration of total serum protein was significantly greater in HIV-positive individuals and in patients with AIDS than in normal individuals. Thus, the nutritional status of patients with AIDS may be a factor for morbidity and mortality.

Evaluation of transthyretin as a monitor of protein-energy intake in preterm and sick neonatal infants.

In the past, weight and weight gain have been the two parameters used frequently in neonatal units to monitor nutrition among high-risk infants. Our investigation sought to assess how several anthropometric measures (weight, length, head circumference, arm:head circumference ratio, and tricep skinfold) and serum albumin, transthyretin, and transferrin concentrations reflect protein and energy intake. After monitoring 42 preterm and 40 sick infants over 3 consecutive weeks, we found that transthyretin concentration proved the only serum protein which accurately measured energy and protein intakes in less than 1 week from dietary manipulation. Among preterm infants, as protein and energy intakes rose, transthyretin concentration increased significantly (p less than 0.001). Preterm infants ingested 79 +/- 39 kcal/kg/day and 2.04 +/- 1.02 g protein/kg/day at the first assessment point after birth and rose to 103 +/- 34 kcal/kg/day and 2.64 +/- 0.94 g protein/kg/day. Likewise, transthyretin measured 10.83 +/- 3.91 mg/dl at the initial measurement and rose to 14.80 +/- 4.44 at the second measurement time. Although protein intakes measured slightly lower in the sick group, their intakes correlated to transthyretin concentration (assessment time 1, r = 0.39; time 2, r = 0.33; time 3, r = 0.33). Thus, transthyretin concentration in neonatal infants offers a rapid, accurate, and moderately inexpensive way to monitor protein-energy adequacy.

Serum prealbumin and retinol-binding protein concentrations in Japanese-type familial amyloid polyneuropathy.

Serum concentrations of prealbumin and retinol-binding protein were measured in 28 patients with Japanese-type familial amyloid polyneuropathy, 46 relatives and normal controls. Both the serum prealbumin and retinol-binding protein concentrations were significantly decreased in the patients when compared with normal controls. The mean serum levels of these proteins in the asymptomatic relatives were intermediate between controls and patients.

Abnormal transthyretin in asymptomatic relatives in familial amyloidotic polyneuropathy.

Familial amyloidotic polyneuropathy (FAP) has been biochemically and genetically proven to be an inherited molecular disorder of transthyretin. (The term transthyretin has been suggested by the Nomenclature Committee of the international Union of Biochemistry and the International Union of Pure and Applied Chemistry for the protein that has heretofore been called prealbumin.) We have experienced three cases that included typical clinical, electrophysiologic, and neuropathologic manifestations of FAP, and yet no known family history of the disorder. The patients and members of their families were studied by radioimmunoassay for a variant transthyretin with a methionine-for-valine substitution at position 30. All three patients had the variant transthyretin in the serum, at concentrations of 54.5, 87.9, and 105.9 mg/L (5.45, 8.79, and 10.59 mg/dL). Although parents and siblings had neither neurologic nor electromyographic evidence of FAP, some of these family members had serum concentrations of variant transthyretin as high as those of the propositi. It was from these asymptomatic parents that the "nonfamilial" patients inherited the gene for FAP. Further study is needed to define the mechanisms retarding or preventing, as well as those promoting, the clinical development of FAP when the variant transthyretin is present in the serum at a high level.

Discriminant biochemical markers for evaluating the nutritional status of elderly patients in long-term care.

To determine the most discriminant serum markers of protein-energy status in elderly patients, we performed a discriminant analysis of 85 subjects grouped according to triceps skinfold and midarm circumference values as compared with reference percentiles. Results indicated that neither the classic serum indices of nutritional assessment nor retinol-binding protein can predict undernutrition. However, creatinine, urea, carotene, complement C3, and prealbumin included in a function enabled high discrimination between groups: 68% of subjects in 0-5th percentile for triceps skinfold and 75% of subjects in 0-5th percentile for midarm circumference are correctly predicted. Lower serum concentration was found in the lower anthropometric percentiles except for serum carotene, which showed an inverse relation not explained by diet. We found that nutritional alterations exist in hospitalized elderly patients. We emphasize the importance of considering several biochemical markers for detection of mal-nutrition and the pertinency of further exploration of serum carotene profiles in undernourished elderly patients.

Evaluation of serum proteins in relation to body nitrogen in tumor-bearing rats.

Assessment of visceral and somatic protein stores by serum proteins in surgical oncology patients has been difficult to interpret. Tumor-bearing (methylcholanthrene sarcoma) (TB) and nontumor-bearing (NTB) Fischer 344 rats were infused with a total parenteral nutrition solution at either 25, 100, or 175% of an infusion rate that provided sufficient nutrients for normal rat growth: On the fifth day after diet initiation, the rats were exsanguinated, decapitated, eviscerated, and skinned. Serum was analyzed for transferrin (TF), complement C3, albumin (ALB), retinol-binding protein (RBP), and transthyretin (TTR). Carcass (CAR) and organ (VIS) nitrogens were determined by the Kjeldahl method. TTR, TF, and RBP correlated significantly with TB and NTB VIS nitrogen and TB CAR nitrogen. The correlation of NTB VIS nitrogen with TTR, TF, and RBP (r range = 0.70-0.85, P less than 0.001) was higher than for TB rats (r range = 0.53-0.57, P less than 0.005). The correlation of TB carcass nitrogen (r range = 0.47-0.51, P less than 0.01) with TTR, TF, and RBP was higher than for NTB carcass nitrogen which was not significant (r range = 0.25-0.37, P less than 0.57). These data indicate that TTR, TF, and RBP do correlate with components of body nitrogen mass, but factors other than nutrition may influence their metabolism in the TB host.

Three immunoassay methods evaluated for quantifying prealbumin (transthyretin) in serum.

We developed an immunoturbidimetric assay for prealbumin on the Cobas Bio centrifugal analyzer and compared results from this assay with those from a rate nephelometric assay (Beckman Instruments Inc.) and a radial immunodiffusion kit (Behring Diagnostics). All three assays were evaluated for precision, linearity, and correlation to each other for analysis of sera from pediatric patients. All assays gave similar results for patients' samples. Values were higher by the radial immunodiffusion assay than by the other two methods, which gave similar results for the same specimens. We conclude that the immunoturbidimetric and rate nephelometric assay for prealbumin are acceptable alternatives for quantifying prealbumin in serum and also have a faster turnaround time than radial immunodiffusion.

The short and long term effect of gastric partitioning surgery on serum protein levels.

The morbidly obese who undergo elective gastric partitioning surgery serve as models of surgical stress and subsequent severe protein calorie restriction. The short and long term effects of gastric partitioning surgery on circulating proteins and the specific micronutrients carried by the proteins were studied in 22 such patients (ages 23-56 years). Serum micronutrient values paralleled the levels of their carrier proteins. Mean concentrations of both short and long turnover proteins decreased significantly in the early postoperative period, whereas the acute phase reactant ceruloplasmin reached preoperative levels by the seventh postoperative day. Transthyretin and retinol binding protein remained depressed with long term reductions in protein and calorie intake, whereas ceruloplasmin and transferrin were somewhat less sensitive to prolonged protein-calorie restriction. Mean serum albumin, after an initial postoperative fall, rose to the baseline level by 1 month after surgery. Serum albumin levels remained within the normal range despite low protein and calorie intakes.

Biochemical characterization of familial amyloidotic polyneuropathy in various districts of Japan.

The purpose of this study is to disclose the molecular basis of type I familial amyloidotic polyneuropathy (FAP) in Japan. Amyloid fibril protein of type I FAP consists of a variant transthyretin (also called prealbumin) with one amino acid substitution of methionine-for-valine at position 30. This variant transthyretin is present in the serum as a precursor protein of amyloid. A radioimmunoassay (RIA) has been established to detect the variant transthyretin. All the 94 patients with FAP who originate from various districts in Japan have the variant transthyretin, but any one of 78 healthy adults of families with FAP do not have it. Half of the symptom-free children of FAP patients have the variant transthyretin even before clinical manifestations appear. The RIA is widely applicable for early diagnosis. The methionine-for-valine substitution is due to a base change from guanine to adenine at the first letter of the valine codon at position 30. Type I FAP in Japan is considered to be a molecular disorder of transthyretin. Since the age of onset ranges from twenties to forties, genetic counseling is recommended to prevent the transmission of this intractable disorder to the next generation.