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Biomedical subjects

J M Culebras

Publications and source records attributed to J M Culebras.

At least 37 records · Page 2Linked to original sources

Total body water and the exchangeable hydrogen. I. Theoretical calculation of nonaqueous exchangeable hydrogen in man.

A theoretical calculation of the total nonaqueous exchangeable hydrogen in protein, carbohydrates, and fat in man has been made. It shows that of the total exchangeable hydrogen in the body 5.22% is located in biochemical components, soluble in body water, containing hydrogen that is exchangeable with the isotope. This value represents a maximum upward distortion of total body water measurements by isotope dilution, due to the maximum possible exchangeability in these molecular conformations. From comparative measurements reported in the literature it is clear that this maximum is not achieved during the short period of time during which tritium-dilution studies are performed. It is the authors' belief that the hard-to-exchange amide hydrogens described by Blout in the protein conformations account for this failure of the isotope to achieve complete exchange in the short time allowed.

Body Water↗

Total body water and the exchangeable hydrogen. II. A review of comparative data from animals based on isotope dilution and desiccation, with a report of new data from the rat.

Total body water (TBW) determination by tritium space could be factitiously elevated by exchangeable H+ contained within water-soluble chemical configurations. Should this nonaqueous (molecular) exchangeable H+ turn out to be a large fraction of total exchangeable H+, TBW measurement by tritiated water (THO) dilution would display a systematic upward and non-random error. TBW was measured by THO dilution and subsequently by total body desiccation in 21 rats (weight 227+/-83 g, mean+/-SD). TBW was 71.38+/-2.4% by THO dilution and 70.20+/-1.5% by body desiccation. Analysis of variance of TBW vs. body weight showed a highly significant correlation both with desiccation (P less than 0.0005, r=-0.78) and dilution (P less than 0.03, r= -0.50). Convariance analysis of both methods showed no difference in slope (P greater than 0.9). There was a difference in variance (P less than 0.001) and means (P less than 0.03). Tritium space is 1.2% of body weight larger than TBW measured by desiccation. TBW measured by THO dilution gives a 1.71% overestimation of TBW as measured by desiccation. TBW measurement by THO dilution is accurate within less than 2% error. These findings have particular significance in the light of our theoretical model of the total nonaqueous exchangeable H+ in fat, protein, and carbodhydrate in the living vertebrate.

Animals↗

Cancer of the pancreas. Palliative operation, Whipple procedure, or total pancreatectomy?

The choice of operation for ductal carcinoma of the pancreas is as yet not clear. Failure to make an early diagnosis still stands out as the major problem in the treatment of this disease and as a result the resectability rate is exceedingly low. Between 1964 and 1973, nineteen total pancreatectomies were performed at Peter Bent Brigham Hospital for all tumors of the pancreas. Sixteen of these were for ductal carcinoma. The mortality was 12.5 per cent. When total pancreatectomy is compared with the Whipple procedure and a simple bypass procedure and when the tumor disease encountered is corrected for stage of disease, it is apparent that total pancreatectomy carries a statistically significant longer survival for patients with Stages I and II disease (no lymph node involvement) than the other two procedures. For Stages III and IV, there is no difference in survival between the three different operations. We therefore conclude that total pancreatectomy carries a better survival prognosis than other procedures performed for Stage I and II ductal carcinoma of the pancreas.

Adult↗

The effects of total parenteral nutrition on the hepatic handling of bilirubin in the rat.

Disturbances of bilirubin metabolism such as jaundice or pigment gallstone formation occur during total parenteral nutrition (TPN). We have studied the effects of TPN on bile flow and bile acid secretion and on the hepatobiliary transport of bilirubin in rats. Animals on parenteral nutrition for 5 days received 4.8 g of amino acids and 6.9 g of glucose daily. Controls were orally fed animals. Bile flow and bile acid secretion were not significantly modified by TPN. Serum bile acid and alkaline phosphatase levels were significantly increased in TPN animals when compared with the controls (+98% and +38%, respectively), which points to a relative cholestasis in the TPN rats. The biliary excretion of bilirubin monoconjugates and bilirubin diconjugates was significantly increased (+72% and +78%, respectively). This provides evidence for enhanced production of the pigment. Serum concentration of total bilirubin was enhanced in the TPN rats (+240%). The esterified/total bilirubin ratio in serum increased, whereas the bilirubin diconjugates/bilirubin monoconjugates ratio decreased. These facts, together with the minor reduction of hepatic bilirubin UDP glucuronosyltransferase activity (-12%), suggest that hyperbilirubinemia would be a consequence of both cholestasis and increased bilirubin production. The alterations reported here could contribute to the explanation of hyperbilirubinemia and pigment gallstone formation in patients maintained on parenteral nutrition.

Animals↗

A study of the delayed hypersensitivity response in healthy people in Spain: Spanish National Tables. National Surgical Infection Committee of the Association of Spanish Surgeons.

With a view to creating national tables of the delayed hypersensitivity response, a total of 1476 healthy persons were studied at eight different locations in Spain. For the measurement of delayed cellular immunity response, Multitest IMC was used. Of those examined, 0.7% were anergic, 21.3 were relatively anergic, and 73 were immunocompetent. Of the 766 men, 28 were relatively anergic and 3 were anergic, whereas of the 710 women, 14 were relatively anergic (p < .001) and 8% were anergic (p < .001). The highest incidence of anergy was found in women of over 70 years (p < .001). Tuberculin was the antigen with the most positive responses, 77%, followed by Candida with 58%. Trichophyton and Proteus mirabilis were the antigens least recognized by the Spaniards studied. Major geographical variations were observed, both in the overall index for the delayed hypersensitivity response and in the response to different antigens. Catalonia revealed the highest level of anergy and the Valencia region, the lowest.

Adult↗

Antipyrine clearance in surgical patients maintained on hypocaloric peripheral parenteral nutrition.

BACKGROUND: Antipyrine clearance (CLAP) constitutes a sensitive indicator of hepatic microsomal enzyme activity providing specific information on hepatic function. The purpose of this study was to evaluate the influence of hypocaloric peripheral parenteral nutrition on CLAP in patients receiving nutrition support after elective surgery. METHODS: CLAP was measured in 15 patients before elective gastrointestinal surgery and 6 days after the surgery. Antipyrine (1 g) was administered orally, and CLAP was determined by the one-sample method. Subjects received a postoperative 786 kcal/d regimen providing 66 g of amino acid per day and 133 g of glucose per day for 5 days. Nutritional status was evaluated by anthropometric parameters. A control group of 15 patients received no postoperative hypocaloric peripheral parenteral nutrition but received conventional fluid therapy. RESULTS: Mean CLAP was increased by 61% (0.66 +/- 0.06 mL/min.kg-1 body wt vs 0.41 +/- 0.05 mL/min.kg-1 body wt in the preoperative period; p < .001), and antipyrine half-life was reduced by 42% (10.9 +/- 1.0 hours vs 18.9 +/- 2.0 hours; p < .001) after 5 days of hypocaloric peripheral parenteral nutrition. No significant modification was shown among control patients in CLAP (0.54 +/- 0.07 mL/min.kg-1 body wt vs 0.46 +/- 0.05 mL/min.kg-1 body wt in the preoperative period) or in antipyrine half-life (14.0 +/- 1.4 hours vs 16.5 +/- 1.8 hours). No significant correlation was observed between CLAP changes and those for the nutritional status of the patients. CONCLUSIONS: The results of our study indicate that oxidative drug-metabolizing capacity is increased in surgical patients maintained on hypocaloric peripheral parenteral nutrition. Clinicians should be conscious of the potential of this effect for altering the efficacy or toxicity of many therapeutic agents.

Adult↗

[Regulatory assessment of the "Nutrición Hospitalaria" journal].

A study is carried out to determine the degree of compliance by the journal entitled "Nutrición Hospitalaria" with the international standards issued by the ISO (International Standards Organization) by means of the application of a survey questionnaire drawn up in accordance with the guidelines published by national and international standards organizations. In total, 161 parameters are considered. Together with the general aspects of the publication, an analysis is made of its specific sections, decisive in the establishment of its level of compliance. After the analysis carried out, it was seen that the general standardization mean was 64% and the real average was 76.82%. At the same time, the necessary recommendations are given to improve these standardization levels and improve the editorial quality of "Nutrición Hospitalaria".

Periodicals as Topic↗

[Assessment of the journal Nutrición Hospitalaria (part I): authors, institutions, articles].

An analysis is made into the productivity of the authors publishing in Hospital Nutrition and the Institutions to which they belong. Spanish authors are dominant, mainly ones from Madrid, and coming to a large extent from the health-care field (75.8%), basically in general hospitals. The types of article very over the period under study, with examples of purely technical articles alongside others such as bibliographical reviews, or Letters to the Editor.

Authorship↗

A new method for surgical treatment of the short bowel syndrome.

This study was aimed to investigate the electrophysiological and morphological characteristics resulting from the structural and functional transformation of gastric tissue transplanted to the small intestine. Twelve adult mongrel dogs were studied up to 3 years. Gastric transplants preserved its main microstructure and minimal compensatory-adaptive processes developed in the mucosa and muscle layers of the graft. A significant influence on the electrical activity of the small intestine was observed, with a 10% reduction of the slow wave frequency (SWF) in the proximal and distal jejunum adjacent to the graft after meals. The SWF of the gastric graft itself, however, corresponded to the frequency of the native stomach, did not depend and was not associated with adjacent intestinal areas. In summary, the stomach graft transplanted to the small intestine keeps the properties of gastric tissue, there are functional adaptations to conditions of digestion in the small intestine and the graft has minimal effects on intestinal motility.

Animals↗

Use of pro-, pre- and synbiotics in the ICU--future options.

Although the word synbiotics was coined to describe the combined action of pre- and probiotics, the ability to, like antibiotics, control infection, the term is now increasingly used in a wider sense, as a name for all the substances released by microbial fermentation in the lower gut. One obvious reason is that most of the substances released seem to influence the immune defense, increase resistance to disease, and, most important, prevent complications to surgery such as infections and thrombosis. Protection layer of lactobacillus does not exist only on the GI tract mucosa, it is important at all exterior body surfaces including those of the eye, the nose, the mouth, the respiratory tract, the vagina, not to forget the skin. It is clearly reduced at all sites when the patient is in the settings of ICU. Each human being has his/her own unique microbial collection, especially of strains of Bifidobacterium and Lactobacillus, and it should be possible to identify an individual on the basis of his/her personal intestinal microflora. The flora seems always to be significantly reduced in the sick, especially in connection with severe disease, care in ICU, and in patients with little food intake or on parenteral nutrition. Supply of both pre- and probiotics can modify functions such as appetite, sleep, mood and circadian rhythm, and this most likely through metabolites produced by microbial fermentation in the gut. Supply of lactic acid bacteria (LAB) can also significantly reduce serum levels of a variety of toxins such as endotoxin. An umbrella of supplemented probiotics could provide to the patients with liver cirrhosis a tool to reduce septic manifestations and the incidence of bleeding. LAB are effective in controlling diarrhea of both bacterial and viral origin. A series of experimental studies and several uncontrolled clinical studies support the idea of using probiotics in patients with IBD. Ecoimmunonutrition with pre- pro- and synbiotics offer to be suitable tools in the new millennium.

Adult↗

[Evaluation of the journal Nutrición Hospitalaria. II. Productivity and collaboration].

An analysis is effected of the production by authors publishing their papers in Nutrición Hospitalaria (Hospital Nutrition), as well as by the institutions at which these authors work. The productivity figures indicate a large group of sporadic authors, whereas the "regular contributors" exceed figure 1 in the indices established. In terms of collaboration, Nutrición Hospitalaria articles present between 3 and 5 signatories per paper, lower than in other journals in the same scientific field.

Humans↗

[Glycine: a cell-protecting anti-oxidant nutrient].

For many researchers it is still difficult to accept that beneficial effects can be obtained in several disease states with the simplest amino acid, glycine. However, evidence is mounting in favour of this idea. It is now clear that dietary glycine protects against shock caused either by blood loss or endotoxin, reduces alcohol levels in the stomach and improves recovery from alcoholic hepatitis, diminishes liver injury caused by hepatotoxic drugs and blocks programmed cell death and reduces the nephrotoxicity caused by the drug cyclosporin A in the kidney, preventing hypoxia and free radical formation. It could be also useful in other inflammatory diseases since it diminishes cytokines production. We review some of the beneficial effects of glycine and their responsible mechanism, which could led to advice its use in the therapy of different diseases.

Anti-Inflammatory Agents↗

[Evaluation of Hospital Nutrition III. Delay, subjects and citation].

We continue with the bibliometric analysis of Nutrición Hospitalaria, in this case providing the data on lag times for the publication of articles, analysis of subject matter, references and citations, including also the calculations of the impact factor, an essential factor for the inclusion of any publication in Current Contents.

Bibliometrics↗

[Flavonoids: properties and anti-oxidizing action].

Flavonoids are phenolic compounds that represent substantial constituents of the non-energetic part of the human diet. They are naturally found in vegetables, berries, fruits, wine and beer. There are more than 5000 different flavonoids. The average intake depend on the country but the average intake is approximately 23 mg/day; quercetin is predominant at 16 mg/day. Flavonoids were considered initially to be substances without any benefit for humans. Later, it has been reported that they exert multiple biological effects due to their antioxidant and free radical-scavenging abilities. Although results from different studies have demonstrated that flavonoids can act as pro-oxidant at very high doses, most investigations have reported anti-inflammatory, antiviral, or anti-allergic effects and a protective role in heart diseases, cancer and different pathologies.

Antioxidants↗