Novel "Matrix-Corrected Calibration" study for the detection of polyunsaturated fatty acids (PUFAs) in plasma and erythrocytes by means of a gas chromatography-mass spectrometry approach optimized to follow up long-term parental patients

An accurate and specific gas chromatography-mass spectrometry (GC-MS) method was optimized to quantify specific polyunsaturated fatty acids (PUFAs) in plasma and in erythrocyte membranes for clinical purposes. The developed and fully-validated method showed optimal linearity in addition to adequate results in terms of accuracy, intra-day and inter-day precision. By adopting the Matrix-Corrected Calibration approach on all the biological matrices tested, both the constant and the proportional errors of the developed analytical methodology were considered to assure that the method was not affected by matrix bias. Moreover, a pilot study involving patients in parental nutrition with two different compositions of the administered fat emulsion was performed. The comparison of results obtained in these patients with a group of healthy subjects (i.e. control population) showed significant differences in the collected values of PUFAs in both plasma and erythrocyte membranes, thus providing evidence that the described GC-MS method could be employed as a simple tool for fast and accurate PUFAs analysis aimed at optimizing parenteral nutrition protocols.

Tumour necrosis factor alpha and oxidative stress as maintaining factors in the evolution of anorexia nervosa

OBJECTIVE

Aim of the study was to evaluate tumour necrosis factor α (TNF-α) axis and oxidative status in patients with anorexia nervosa (AN) seeking a possible correlation with both nutritional status and evolution of the disease.

SUBJECTS AND METHODS

Thirty-nine consecutive women with AN and an age-matched healthy control group were studied. Patients were 26±9 yr, with a body mass index (BMI) of 13.9±2 kg/m(2). TNF-α, its receptors TNF-R55 and TNF-R75, and oxidative status markers (selenium, ascorbic/ dehydroascorbic acid, retinol, α-tocopherol, selenium-dependent gluthatione peroxidase, reduced/oxidated gluthatione) were measured. A correlation with both nutritional indexes (body weight, BMI, albumin, prealbumin, transferrin, lymphocyte count) and disease duration was investigated. Pearson's correlation and unpaired Student's t-test were used to compare patients and controls.

RESULTS

TNF-α and oxidative status markers were significantly higher in patients than controls and TNF-α was directly related to dehydroascorbic acid (p<0.05). Both TNF-R55 and TNF-R75 were higher in patients with duration of disease longer than one year as compared to controls and patients with shorter duration. Receptors inversely correlated with BMI (p<0.05 and p<0.01) and directly with disease duration (p<0.05). Inverse correlation between disease duration and BMI was present (p<0.01).

CONCLUSIONS

The study showed activation of TNF-α axis and oxidative stress in AN patients, as well as correlation between the two systems. Due to the correlation between TNF receptors and both BMI and disease duration, a possible role of pro-inflammatory cytokines in the evolution of the eating disorder is suggested.

Oxidative stress in stable cystic fibrosis patients: do we need higher antioxidant plasma levels?

Oxidative stress plays an important role in cystic fibrosis (CF). However, there is a lack of validated biomarkers of oxidative damage that correlate with the antioxidant needs of patients with CF.

OBJECTIVE

To investigate oxidative stress in stable pediatric CF patients and evaluate if vitamin supplementation may be tailored to individual needs and oxidative status.

RESULTS

Lipid-adducts 4-hydroxynonenal (HNE-L) and malonaldehyde (MDA-L) (chromolipids) were elevated in the majority of patients despite normal plasma vitamin E, A and C. HNE-L and MDA-L increased with age, while plasma vitamins decreased. The most relevant correlation was identified between vitamin C and chromolipids. Patients with pancreatic insufficiency (PI) showed significantly higher plasma chromolipids despite no differences in plasma vitamins.

CONCLUSIONS

The majority of patients showed elevated plasma chromolipids that increased with age. Antioxidant vitamin reference ranges provide incomplete information on the redox status. CF patients with PI showed excessive oxidative stress damage.

4-Hydroxynonenal is Markedly Higher in Patients on a Standard Long-term Home Parenteral Nutrition

Parenteral nutrition, a commonly used procedure in patients with gastrointestinal disorders, may lead with time to liver steatosis and fibrosis, whose pathogenesis has yet to be elucidated. Oxidative stress and particularly lipid peroxidation likely contribute to the expression of such hepatobiliary complications, by means of their recognized proinflammatory and profibrogenic effects. To evaluate the adequacy against oxidative insult of a standard micronutrient supplementation in patients under long term parenteral nutrition, a comprehensive patterns of redox indices has been determined on peripheral blood samples from forty one adults in comparison to fifty eight blood donors taken as controls. A sustained oxidative stress in peripheral blood of home parenteral patients was observed. Of the two lipid peroxidation markers found to be markedly increased, namely fluorescent plasma protein adducts with malondialdehyde and 4-hydroxynonenal, respectively, only the second was statistically correlated with all the antioxidant-related changes consistently detected in the patients, namely decreased plasma alpha-tocopherol and selenium intake and higher erythrocyte oxidized glutathione. Plasma level of 4-hydroxynonenal-protein adducts appears to be a reliable and easily measurable marker of oxidative status, particularly indicated to monitor the adequacy of dietary regimen during parenteral nutrition.

Long-term N-acetylcysteine and L-arginine administration reduces endothelial activation and systolic blood pressure in hypertensive patients with type 2 diabetes

OBJECTIVE

Reactive oxygen and nitric oxide (NO) have recently been considered to be involved in the cardiovascular complications of patients with type 2 diabetes, as NO is thought to lose its beneficial physiological effects in the presence of oxygen radicals. For this reason, we tested the effects of l-arginine (ARG) and N-acetylcysteine (NAC) administration in increasing NO bioavailability by reducing free radical formation.

RESEARCH DESIGN AND METHODS

A double-blind study was performed on 24 male patients with type 2 diabetes and hypertension divided into two groups of 12 patients that randomly received either an oral supplementation of placebo or NAC + ARG for 6 months.

RESULTS

The NAC + ARG treatment caused a reduction of both systolic (P < 0.05) and diastolic (P < 0.05) mean arterial blood pressure, total cholesterol (P < 0.01), LDL cholesterol (P < 0.005), oxidized LDL (P < 0.05), high-sensitive C-reactive protein (P < 0.05), intracellular adhesion molecule (P < 0.05), vascular cell adhesion molecule (P < 0.01), nitrotyrosine (P < 0.01), fibrinogen (P < 0.01), and plasminogen activator inhibitor-1 (P < 0.05), and an improvement of the intima-media thickness during endothelial postischemic vasodilation (P < 0.02). HDL cholesterol increased (P < 0.05). No changes in other parameters studied were observed.

CONCLUSIONS

NAC + ARG administration seems to be a potential well-tolerated antiatherogenic therapy because it improves endothelial function in hypertensive patients with type 2 diabetes by improving NO bioavailability via reduction of oxidative stress and increase of NO production. Our study's results give prominence to its potential use in primary and secondary cardiovascular prevention in these patients.

Efficacy of antioxidant treatment in reducing resistin serum levels: a randomized study

Objectives:

Few in vitro studies have examined the participation of resistin, a recently discovered adipokine, in oxidative processes. We investigated whether in vivo treatment with the antioxidant vitamin C might affect resistin serum levels.

Design:

Randomized prospective open trial.

Setting:

San Giovanni Battista Hospital, Turin, Italy.

Participants:

Eighty healthy individuals.

Intervention:

Administration of 2 g of ascorbic acid orally for 2 wk (n = 40; experimental group) or no supplementation (n = 40; control group).

Outcome measures:

The primary end point was the between-group difference in the before–after change in resistin serum level after vitamin C supplementation. Secondary endpoints were the within- and between-group changes in glucose, insulin, lipid parameters, C-reactive protein fasting values, and markers of oxidative stress.

Results:

In the experimental group, vitamin C supplementation was significantly associated with both resistin concentration reduction (from 4.3 ± 1.5 to 2.9 ± 0.8 ng/ml; 95% confidence interval [CI] −1.87, −1.03) and ascorbic acid level increase (from 9.4 ± 2.9 to 19.0 ± 5.2 mg/l; 95% CI 7.9, 11.2). In the control group, resistin levels did not change significantly (from 4.2 ± 1.0 to 4.3 ± 0.9 ng/ml; 95% CI −0.07, 0.37). The between-group differences were highly significant (p < 0.001). Vitamin C supplementation was also associated with a statistically significant reduction in nitrotyrosine level and incremental increase in reduced glutathione. In a linear regression model, within-individual changes in vitamin C concentrations were inversely correlated with changes in resistin levels in both groups (each unit increase of vitamin C corresponded to a decrease of about 0.10 units of resistin levels (95% CI 0.13, 0.08; p < 0.001).

Conclusion:

This is to our knowledge the first randomized trial in humans that has demonstrated that short-term vitamin C supplementation could significantly reduce resistin levels, independent of changes in inflammatory or metabolic variables. Future investigations of resistin participation in oxidative processes are warranted.

Background: Resistin is a hormone that is produced by fat cells. Much of the work on resistin has been done in mice, and as a result of this research the hormone was thought to explain the link between obesity and development of diabetes. In obese mice, higher levels of resistin are seen, and this hormone seems to interfere with the normal role of insulin in reducing blood sugar levels. However, the exact biochemical pathways in mice and humans seem to be very different, and it is not obvious whether resistin plays the same role in the development of diabetes in humans as it does in mice. At the same time, some researchers have suggested links between resistin and oxidative stress, which is thought to be involved in the development of certain diseases, particularly cardiovascular disease. The researchers here wanted to more fully explore these links by finding out whether an antioxidant, vitamin C, affected levels of resistin in blood. The researchers carried out a trial in healthy human participants, who were randomized to receive 2 g of vitamin C daily for two weeks, or no treatment. The primary outcome of the trial was the change in resistin levels in blood, and the researchers also looked at the levels of other biochemical variables in blood, such as fasting glucose, insulin, cholesterol, fatty acids, and nitrotyrosine.

What the trial shows: The researchers recruited 80 participants into the trial, and 40 were randomized to receive 2 g of vitamin C supplementation for two weeks. Forty individuals acted as “controls” and received no intervention over the two weeks of the trial. Outcomes were assessed for all but two individuals in the control group. Overall, levels of resistin in blood fell substantially over the course of the trial among the individuals in the vitamin C supplementation group, but not in the control arm of the trial, and this difference between groups was statistically significant. The levels of many other biochemical markers in blood, such as glucose, cholesterol, fatty acids, and insulin, did not show statistically significant changes between the randomized groups. However, levels of two markers of oxidative stress did change: levels of nitrotyrosine, which is associated with cell damage and inflammation, seemed to drop in the vitamin C group relative to the control group, and levels of reduced glutathione (an antioxidant) seemed to increase in the vitamin C group relative to the control group.

Strengths and limitations: In this trial, all individuals were randomized at once to the two study groups. While this is unconventional (normally, participants are randomized one by one, as they are screened and deemed eligible for a study), the process would be likely to prevent bias in allocation of individuals to the study groups. Although participants were not blinded to which study group they were assigned to, the laboratory staff measuring biochemical marker levels in blood were blinded to the study groups. A key limitation of this study is that the participants in the control arm did not receive placebo tablets, but rather received no treatment. A placebo control group would have enabled the researchers to blind participants as to whether they received vitamin C or no active intervention. Participants' knowledge of their group assignment (e.g., to receive vitamin C or no intervention) may have affected their response in the trial. Finally, the trial was conducted on a small group of healthy individuals, and no clinical outcomes were examined. Therefore, although the findings are intriguing, their clinical meaning is not clear.

Contribution to the evidence: There are few other studies that have been carried out in humans examining the possibility of a link between resistin levels and oxidative stress. This study suggests that vitamin C administration reduces blood levels of resistin in humans. This finding does not yet clearly point to a specific role for resistin in disease processes or human disease, but raises questions for further study.

Long-term, low-dose, intravenous vitamin C leads to plasma calcium oxalate supersaturation in hemodialysis patients

BACKGROUND

Ascorbate supplementation for patients on regular dialysis treatment (RDT) is advised to obviate deficiency and improve epoetin response in those with functional iron deficiency. However, clear-cut safety concerns regarding hyperoxalemia are still poorly understood. This study tries to establish safety/efficacy profiles of ascorbate and oxalate during long-term intravenous ascorbate supplementation.

METHODS

A prospective study was performed in 30 patients on RDT showing ascorbate deficiency (plasma ascorbate < 2.6 mg/L [<15 micromol/L]): 18 patients were administered intravenous ascorbate during 18 months (250 mg/wk, subsequently increased to 500 mg), and 12 patients were taken as reference untreated cases. Plasma ascorbate and oxalate assays and dialytic balance determinations were performed (ion chromatography and reverse-phase high-performance liquid chromatography, respectively) at baseline, during treatment, and 12 months after withdrawal.

RESULTS

Plasma ascorbate levels increased dose dependently with supplementation (1.6 +/- 0.8 mg/L [9.1 +/- 4.6 mumol/L] at baseline, 2.8 +/- 1.8 mg/L [15.9 +/- 10.1 micromol/L]) with 250 mg of ascorbate, and 6.6 +/- 2.8 mg/L [37.5 +/- 16.0 micromol/L] with 500 mg/wk of ascorbate), but only normalized with greater dosages for several months in 94% of patients. Baseline plasma oxalate levels increased from 3.2 +/- 0.8 mg/L (35.8 +/- 8.8 micromol/L) to 3.6 +/- 0.8 mg/L (39.5 +/- 9.1 micromol/L) and 4.5 +/- 0.9 mg/L (50.3 +/- 10.4 micromol/L) with 250 and 500 mg, respectively ( P < 0.001). The calcium oxalate saturation threshold was exceeded by 7 of 18 patients (40%) during 6 months therapy with 500 mg/wk. Ascorbate dialysis removal increased from 37.8 +/- 23.2 mg (215 +/- 132 micromol) to 99.6 +/- 51.7 mg (566 +/- 294 micromol) during supplementation (P < 0.001), with corresponding increases in oxalate removal from 82.5 +/- 33.2 mg (917 +/- 369 micromol) to 111.2 +/- 32.6 mg/L (1,236 +/- 362 micromol; P < 0.01). Withdrawal reverted plasma levels and dialysis removal to initial values. Values for untreated patients did not change during 1 year of follow-up.

CONCLUSION

Patients on RDT may resolve ascorbate deficiency with intravenous supplementation of 500 mg/wk, but this implies a significant risk for oxalate supersaturation. Oxalate measurements are strongly recommended during long-term ascorbate therapy.

Relative contribution of iron burden, HFE mutations, and insulin resistance to fibrosis in nonalcoholic fatty liver

The mechanism(s) determining the progression from fatty liver to steatohepatitis is currently unknown. Our goal was to define the relative impact of iron overload, genetic mutations of HFE, and insulin resistance on the severity of liver fibrosis in a population of subjects with nonalcoholic fatty liver disease (NAFLD) who had low prevalence of obesity and no overt symptoms of diabetes. In a cohort of 263 prospectively enrolled patients with NAFLD, 7.4% of patients had signs of peripheral iron overload and 9% had signs of hepatic iron overload, but 21.1% had hyperferritinemia. The prevalence of C282Y and H63D HFE mutations was similar to the general population and mutations were not associated with iron overload. Although subjects were on average only moderately overweight, insulin sensitivity, measured both in the fasting state and in response to oral glucose, was lower. Univariate analysis demonstrated that the presence of severe fibrosis was independently associated with older age, female sex, overweight, aspartate/alanine aminotransferase ratio, serum ferritin level, fasting glucose and insulin levels, decreased insulin sensitivity, and with histologic features (degree of necroinflammation and steatosis). After adjustment for body mass index (BMI), age, sex, and degree of steatosis, ferritin levels (odds ratio [OR] = 1.77; 95% CI = 1.21- 2.58; P =.0032) and the oral glucose insulin sensitivity (OR = 0.53; CI = 0.33-0.87; P =.0113) were independent predictors of severe fibrosis. In conclusion, the current study indicates that insulin resistance is a major, independent risk factor for advanced fibrosis in patients with NAFLD. Increased ferritin levels are markers of severe histologic damage, but not of iron overload. Iron burden and HFE mutations do not contribute significantly to hepatic fibrosis in the majority of patients with NAFLD.

Brain manganese deposition and blood levels in patients undergoing home parenteral nutrition

BACKGROUND

Extrapyramidal syndrome and alterations in brain magnetic resonance images are described in patients undergoing long-term home parenteral nutrition (HPN) and in cholestatic patients. These abnormalities have been correlated to basal ganglia manganese (Mn) accumulation.

METHODS

A longitudinal 1-year study was conducted on 15 patients undergoing HPN (median duration, 3.8 years; range, 1.7-10; median Mn parenteral supplementation, 0.1 mg/d). Whole-blood, plasma, intra-erythrocytes, and urinary Mn concentrations were measured and brain magnetic resonance was performed at the beginning (time 0) and after 1 year of Mn intravenous supplementation withdrawal (time 1). No patients showed psychosis, extrapyramidal syndrome, or cholestasis.

RESULTS

At time zero, 10 of 15 patients (67%) showed paramagnetic accumulation on cerebral magnetic resonance images; at time 1 there was a reduction of cerebral Mn accumulation. In all patients, blood-Mn levels were significantly reduced after 1 year of Mn intravenous supplementation withdrawal.

CONCLUSIONS

Patients receiving long-term HPN showed an elevated incidence of alterations in brain magnetic resonance images with a median Mn intravenous supplementation of 0.1 mg/d. Mn supplementation withdrawal significantly decreased metal levels in blood and brain storage. We noticed that the intra-erythrocyte Mn level was a good index of Mn status.

[The nutritional aspects in autologous bone marrow transplantation]

The use of total parenteral nutrition (TPN) in bone marrow transplant recipients is well recognized. These patients, as a result of treatment with chemotherapy and immunosuppressive agents, undergo catabolic stress. In stressed patients attention has been focused on the optimal calorie: nitrogen ratio of total parenteral nutrition formulations. Theoretically, TPN formulas of low calorie: nitrogen ratio impede body protein catabolism. In bone marrow transplant patients negative nitrogen balance may persist despite high nitrogen intake. The purpose of the present study is to determine the effect of increasing nitrogen intake on nutritional and metabolic parameters in bone marrow transplant patients. The metabolic effect of an increased nitrogen dose during TPN was studied in 33 bone marrow transplant patients, divided into 2 groups. Patients were given total parenteral nutrition formulas providing a protein intake of 1.4 +/- 0.2 g of protein/kg IBW/day for the first group, and 2.3 +/- 0.12 g of protein/kg IBW/day for the II group. Total calories, non protein and protein, were held constant at 40 kcal/kg IBW/day for all patients. Data have been calculated for 4 weeks starting from the first week pretransplant. As we had expected, the patients who are the object of the present study were well nourished at the time of hospital admission, confirming the description of bone marrow transplant recipients published by other transplant centers. Relative body weight, total serum protein, albumin, prealbumin and cholesterol were not significantly different at any study period.(ABSTRACT TRUNCATED AT 250 WORDS)

[Trace nutrients in total enteral nutrition: the basal status and longitudinal course]

INTRODUCTION

Previous studies demonstrated deficiencies of selenium and other micronutrients in patients receiving total enteral nutrition (TEN). The content and bioavailability of trace elements in enteral formulas can be suboptimal.

MATERIAL AND METHODS

Basal blood levels of some trace elements (copper, iron, selenium, zinc) and vitamins (B12, folic acid) were determined in twenty patients at the beginning of TEN. Vitamin E was measured in 7 patients. Primary diagnosis was cancer (no. = 13) and organic brain syndromes (no. = 7). Commercially available polymeric and oligomeric enteral formulas were used, containing respectively, as a percent of RDA in 1500 kcal, 65-39% of copper, 180-135% of iron, 80-100% of zinc. Selenium was not indicated; determinations in our laboratory gave a content of 78-63% of the minimum recommended intake. Blood levels of copper and zinc (no. = 6), selenium (no. = 5), iron, transferrin and ferritin (no. = 13) were measured after two months of TEN (mean intake of 30 +/- 3 kcal/kg/day). Copper, selenium and zinc were measured with atomic absorption; iron with the complessometric method: vitamin B12 and folic acid with RIA; vitamin E with HPLC.

RESULTS

Mean values, expressed as mean +/- SD (range) were: copper: 129 +/- 23 (82-300) micrograms/dl; iron: 37 +/- 18 (16-89) mg/dl; selenium: 53 +/- 20 (22-93) micrograms/dl; zinc: 85 +/- 34 (44-185) micrograms/dl; vitamin B12: 632 +/- 450 (140-1575) pg/ml); vitamin E: 5.4 +/- 1.5 (3.3-7.8) mg/dl; folic acid: 11 +/- 8 (2-20) ng/ml. Values below the lower normal limit were found in 100% (vitamin E), 89% (selenium), 60% (iron), 35% (zinc), 24% (vitamin B12) and 14% (folic acid) of the patients studied. Copper was higher than the upper normal limit in 31% of cases; no data below normal range was found. Mean blood levels of depleted subjects were at the 28%, 43%, 54% and 63% of the mean normal value respectively for iron, selenium, vitamin E and zinc. Blood iron (p < 0.05) and selenium (p < 0.001) were significantly lower in more malnourished patients (weight loss > 20% vs < 20% on usual body weight). After two months of TEN, a reduction of 33% of mean blood selenium was observed in 4 of 5 patients studied. Blood copper and zinc remained stable in 6 subjects with initial normal or higher than normal values. Blood iron increased nonsignificantly, ferritin remained stable, transferrin increased significantly (p < 0.05). No clinical deficiency syndromes were observed.

CONCLUSIONS

A careful monitoring of micronutrients during TEN is recommended. Selenium content of enteral formulas, unless supplemented by the producers, seems to be insufficient to maintain the initial blood level in two months of TEN.

[Dietetic and pharmacologic treatment of hypercholesterolemia. Study of 32 patients over 14 months]

The aim of the study was to evaluate the effectiveness of dietetic-behavioural and pharmacological treatment on 32 patients with high level hypercholesterolemia (LDL-c greater than 160 mg/dl) over 14 months. Clinical and laboratory tests were performed at time 0 (enrollment), at time 1 (after 2 months dietetic-behavioural treatment only), at time 2 and time 3 (after 6 and 12 months respectively of combined dietetic-behavioural and pharmacological treatment). The dietetic-behavioural treatment consist of reduced intake of saturated fatty acids, cholesterol and rapidly absorbed glycid; increased intake of omega-3 fatty acids and fiber; reduced overall calorie intake. The patients were also advised to take light daily exercise. The pharmacological treatment (sinivastatin 20 mg/die) was given to patients whose total cholesterol levels were over 250 mg/dl after 60 days of dietetic-behavioural only treatment and then continued for the whole study. The result showed an average reduction of 20% (p less than 0.01) in LDL-c in all patients after dietetic-behavioural only treatment and a further 20% (p less than 0.01) reduction after 12 months of combined treatment. There was therefore confirmation of the validity of dietetic-behavioural and pharmacological treatment during our study.

[Nutritional assessment of aged patients with fractures of the proximal epiphysis of the femur]

Forty-two patients (M/F 9/33; age 78 +/- 10 years) were studied during Hospital stay for femoral neck fractures (16 neck, 26 pertrochanteric fractures). All underwent fracture surgery (internal fixation in 30, arthroplasty in 12 patients). Food intake was evaluated daily, supplemented with specific recipes. Biochemical assessment of nutritional status (hemoglobin, hematocrit, total proteins, albumin, prealbumin, Na, K, Ca, Fe, P, Mg) was performed before and after surgery. Nitrogen balance was evaluated in 8 patients in the post-operative period (40 determinations). The study group was compared for post-surgical complications and mortality during Hospital stay with a historical control group without any nutritional survey. Mean daily caloric intake was (M +/- DS) 1014 +/- 360 in the preoperative period, 960 +/- 210 and 1036 +/- 185 postoperatively (5-9 and 10-15 days post-surgery, respectively). Mean nitrogen intake was, respectively, 7.5 +/- 2.6, 7 +/- 2.1, 6.9 +/- 1.6 gN/day. No significant differences were found. In the preoperative period, the following tests were found below the normal range: iron (median 30 micrograms/dL), albumin (median 3.1 g/dL), hemoglobin (median 12 g/dL) hematocrit (median 35%). After surgery, they decreased significantly; also prealbumin, in normal limits before surgery (20 +/- 0.7 mg/dl), decreased significantly 5-9 days after surgery. After 10-15 days from surgery, only prealbumin and iron reached the preoperative level.(ABSTRACT TRUNCATED AT 250 WORDS)

Proposal of a new formula to calculate total urinary nitrogen from urea urinary nitrogen

Urea urinary nitrogen (UUN) and total urinary nitrogen (TUN) were determined in 15 patients to study their relationship mainly in highly catabolic patients. The subjects were: 7 multiple trauma, 3 autologous bone-marrow transplant, 1 tetanus, 4 postcholecystectomy patients; 180 determination were made, 111 of which in highly catabolic phase (TUN > 15 g/day). TUN and UUN are well correlated (r = 0.9742; p < 0.001) in the range 3 to 52 g/ day of TUN. Urea represents the 83.2 +/- 9.4% (M +/- SD). A double-linear formula to calculate TUN from UUN is proposed (for UUN 15 g/ day: TUN = UUN x 1.17 + 0.7; for UUN > 15 g/ day: TUN = UUN + 4). The least square procedure was used to compare the differences between measured and calculated TUN, and the results obtained with the proposed double-linear formula were compared with that obtained employing pre-existing formulas (Lee's and Mackenzie's). Considering all ranges of values studied (3-52 g of TUN) the results obtained were significantly different (p < 0.005); dividing the levels of TUN in 15 g; 16-29 g and 30 g, the results were always better, but the statistical significancy was not always reached.

Effect of regular and decaffeinated coffee on serum gastrin levels

We evaluated the hypothesis that the noncaffeine gastric acid stimulant effect of coffee might be by way of serum gastrin release. After 10 healthy volunteers drank 50 ml of coffee solution corresponding to one cup of home-made regular coffee containing 10 g of sugar and 240 mg/100 ml of caffeine, serum total gastrin levels peaked at 10 min and returned to basal values within 30 min; the response was of little significance (1.24 times the median basal value). Drinking 100 ml of sugared water (as control) resulted in occasional random elevations of serum gastrin which were not statistically significant. Drinking 100 ml of regular or decaffeinated coffee resulted in a prompt and lasting elevation of total gastrin; mean integrated outputs after regular or decaffeinated coffee were, respectively, 2.3 and 1.7 times the values in the control test. Regular and decaffeinated coffees share a strong gastrin-releasing property. Neither distension, osmolarity, calcium, nor amino acid content of the coffee solution can account for this property, which should be ascribed to some other unidentified ingredient. This property is at least partially lost during the process of caffeine removal.