Clinical presentation and time course in hypersensitivity reactions to beta-lactams.

BACKGROUND: beta-lactam hypersensitivity reactions are classified as immediate or nonimmediate. Diagnosis is usually based upon skin tests and provocation challenges. OBJECTIVE: The time course of the reactions in proven beta-lactam hypersensitivities was studied and then correlated with the symptoms to determine the relationship between the clinical presentations and the time course. METHOD: All of the patients who consulted between 1996 and 2004 for a suspected beta-lactam hypersensitivity reaction were studied. Two hundred and ten patients with a proven hypersensitivity reaction diagnosed according to the European Network on Drug Allergy were included in the present study. RESULTS: Of the patients, 36.7% had urticaria as a single symptom, 19.1% anaphylaxis without shock, 17.6% anaphylactic shock and 19.1% maculopapular exanthema. Anaphylactic shock and anaphylaxis mostly occurred within 1 h after drug administration. Exanthema mainly occurred after 24 h. Urticaria as a single symptom occurred at any time. A firm diagnosis was determined using immediate-reading skin prick (10.0%) and intradermal tests (38.1%), late-reading skin tests (19.1%) or provocation tests (32.9%). CONCLUSION AND CLINICAL IMPLICATION: Depending on the time course of the reaction, three clinical groups were identified: anaphylaxis and anaphylactic shock (immediate reaction); maculopapular exanthema (late reaction) as well as urticaria (immediate and late reaction).

Diagnosis of neuromuscular blocking agent hypersensitivity reactions using cytofluorimetric analysis of basophils.

BACKGROUND: Immunoglobulin E (IgE)-mediated hypersensitivity reactions to neuromuscular blocking agents (NMBA) are common and life threatening. Basophil activation based upon the expression of CD63 in the presence of specific allergens was found to be of importance for the diagnosis of IgE-mediated hypersensibility. METHODS: The Basotest was evaluated for the diagnosis of NMBA in 47 patients with proven NMBA anaphylaxis, 40 atopic subjects nonallergic to NMBA and five healthy volunteers. Diagnosis of NMBA was made according to international standards on clinical history, skin tests and provocation tests when needed. RESULTS: In the NMBA allergic patients, sensitivity of Basotest was 36.1%, but it increased to 85.7% for reactions which occurred within the last 3 years. The specificity was 93.3%. CONCLUSION: Basotest may be useful for the diagnosis of NMBA allergy in patients with a suspicion of recent IgE-mediated hypersensitivity reaction to NMBA.

Increased bronchoalveolar lavage CD8 lymphocyte subset population in wheezy infants.

Episodes of wheezing are very common in infancy but, despite their high prevalence, their mechanism is still poorly understood. To better understand the airway inflammation of wheezing infants, we examined cells of the bronchoalveolar lavage (BAL), focusing on the phenotype of lymphocytes and macrophages by using cytofluorimetry. Twenty-one wheezers (mean age 15.4 months) and seven non-wheezers (mean age 24.1 months) were studied. BAL was collected at fiberoptic bronchoscopy. Total and differential cell counts were similar in both populations. Eosinophils were not detected in the BAL fluid. The cell-surface markers CD2, CD3, CD4, CD7, CD8, CD19, and CD45 were studied for the lymphocyte sub-population analysis. The cell-surface markers CD14, CD54, CD62L, and human leucocyte antigen (HLA)-DR were studied for the macrophage sub-population analysis. A significant increase in the CD8(+) lymphocyte population (p = 0.03) was observed in wheezers (median 43.1%, 25-75% percentile: 30.1-54.9%), as compared to non-wheezers (median 29.3%, 25-75% percentile: 13.5-34.7%). A significantly (p = 0.04) decreased expression of HLA-DR (mean fluorescence intensity [MFI]) was detected in the macrophage population of the wheezers (median MFI, 7,016; range 2135-7986), as compared to non-wheezers (median MFI, 8,369; range: 6478-8860). The results of the present study suggest that viral infection may have induced a CD8(+) response in BAL cells.

Cysteinyl-leukotriene release test (CAST) in the diagnosis of immediate drug reactions.

BACKGROUND: The diagnosis of allergic reactions to drugs is difficult. Most skin tests are not standardized, and in vitro tests are needed to avoid provocation tests. Cross-linking of IgE on basophils is known to cause the release of both cysteinyl leukotriene (Cys-LT) and histamine. We aimed to evaluate the diagnostic utility (sensitivity, specificity, and efficiency) of measurement of sulfidoleukotrienes in drug allergy. METHODS: We performed a prospective study in 55 patients with proven immediate adverse reactions to drugs (30 to beta-lactams, six to acetaminophen, and 19 to aspirin) and 64 drug-exposed nonallergic controls. Positive diagnosis was established by history, skin tests, and, if needed, oral provocation tests. Cys-LT release was determined after drug-allergen stimulation by the cellular antigen stimulation test (CAST(R)) technique. Histamine release was also assessed on the same samples by enzyme immunoassay. Spontaneous and anti-FcepsilonRIalpha-induced mediator release was also studied in all subjects. Sensitivity, specificity, and efficiency were calculated. RESULTS: Net Cys-LT release was over the maximal threshold given by the manufacturer in 19/55 patients and in 9/64 controls. Net histamine release was over 5% of total histamine content in 28/55 patients and 34/64 controls. The efficiency of both tests was low. CONCLUSION: Thus, in most cases, the in vitro Cys-LT test has little or no diagnostic utility and is not superior to histamine release.

Duodenal vs. gastric administration of labeled leucine for the study of splanchnic metabolism in humans.

Low-rate (6 ml/h) intragastric infusion of stable, isotope-labeled amino acids is commonly used to assess the splanchnic handling of amino acids in humans. However, when used in the postabsorptive state, this method yields unreliable plasma isotopic enrichments, with a coefficient of variation >10%. In this metabolic condition, we confirmed in six subjects that an intragastric infusion of L-[(2)H(3)]leucine at 6 ml/h yields an unreliable isotopic steady state in plasma amino acids with a coefficient of variation of 43 +/- 12% (mean +/- SD). In five additional subjects, we assessed the effects of 1) increasing the rate of delivery of a leucine tracer in an isotonic plasmalike solution at 240 ml/h into the gastric site, and 2) changing the site of infusion from gastric to duodenal with this same high rate of delivery. In contrast to the gastric route, and regardless of the rate of delivery, only the intraduodenal route allowed 1) isotopic plasma steady state (i.e., coefficients of variation were <10%: 5 +/- 3%), and 2) reproducible leucine extraction coefficients (22 +/- 5%). We conclude that an infusion site that bypasses the gastric emptying process, i.e., the duodenal route, along with delivery of a plasmalike solution, is necessary to reach isotopic steady state in plasma when labeled leucine is infused into the gastrointestinal tract in the postabsorptive state.

Predictive capacity of histamine release for the diagnosis of drug allergy.

BACKGROUND: The diagnosis of immediate allergic reactions to drugs is difficult, requiring in vitro test development. Basophils are likely to be involved in these reactions, and to evaluate the sensitivity, the specificity, and the predictive values of the histamine-release test, we performed a prospective study in 68 patients tested for suspected drug allergy. METHODS: Positive diagnosis was established by history, skin tests, and, if needed, oral provocation tests. Histamine release in the presence of the drug was assessed on heparinized whole blood by enzyme immunoassay (Immunotech, France), and the cutoff value was set at 5% of total histamine content. Spontaneous and anti-IgE-induced histamine release was also studied in all subjects. RESULTS: All patients presented to our clinic with reactions ranging from maculopapular exanthema to anaphylactic shock. Thirty-five patients had proven drug allergy; 33 were not allergic to drugs and served as a control group together with 40 other subjects with no history of drug allergy. Net histamine release was positive in 18/35 allergics and 27/73 nonallergics, giving poor sensitivity (51.4%), specificity (63.0%), and positive predictive value (29.3%), but valuable negative predictive value (81.1%). CONCLUSIONS: The usefulness of the in vitro histamine-release test for the diagnosis of drug allergy appears to be insufficient.

Energy and protein metabolism during recovery from malnutrition due to nonneoplastic gastrointestinal disease.

The magnitude of metabolic adaptation to malnutrition is still debated and few studies have investigated the phase of recovery from malnutrition. The aim of the present work was to determine whether refeeding was associated with adaptive changes in 1) energy expenditure, 2) maximal capacity for oxidizing lipids, and 3) whole-body protein turnover. Eleven malnourished patients with nonneoplastic gastrointestinal diseases were studied by using indirect calorimetry and L-[1-13C]leucine infusion while being infused with lipid-rich total parenteral nutrition (TPN). The same study was performed before initiation of TPN and after a mean gain of 6.5 kg body wt. In absolute values, resting energy expenditure (REE) increased after refeeding (4.05 +/- 0.85 compared with 4.60 +/- 1.05 MJ/d). Change in REE adjusted for fat-free mass (FFM) correlated significantly with change in body weight (r = 0.850, P = 0.01) and change in body fat (r = 0.798, P = 0.01) but not with change in FFM (r = -0.06, NS). Lipid oxidation decreased significantly after body weight gain (0.93 +/- 0.28 compared with 0.50 +/- 0.37 mg.kg-1.min-1). When expressed per kg FFM, protein turnover and breakdown increased significantly during body weight gain. Moreover, the change in protein turnover correlated with the rate of change in FFM, suggesting that FFM accretion requires increased interorgan exchange of amino acids. Our data suggest that in patients similar to those studied here and during recovery from malnutrition, the degree of change in adjusted REE during refeeding is correlated with change in fat mass and not with change in FFM, and that there is a decrease in oxidation of infused lipids. These mechanisms may contribute to body fat repletion and regulation during weight gain.

Energy and protein metabolism in malnutrition due to nonneoplastic gastrointestinal diseases.

Although a reduction in both energy expenditure and protein turnover has been demonstrated in starved volunteers, few metabolic data are available for patients in whom malnutrition is due to nonneoplastic gastrointestinal diseases. Chronically malnourished, unstressed adult patients with nonneoplastic gastrointestinal diseases (body mass index, 15.8 +/- 2.5 kg/m2, n = 13) and healthy control subjects (n = 10) were studied in the postabsorptive state using indirect calorimetry, as well as substrate fluxes of L[1-13C]leucine, L-[2-15N]glutamine (seven patients and six controls), and D[6,6-2H2]glucose (seven patients and eight controls). Resting energy expenditure (REE) expressed in kilocalories per 24 hours was significantly lower in patients than in controls; REE expressed per unit of fat-free mass (FFM) was not significantly different in both groups. Whole-body leucine turnover, oxidation, and nonoxidative disposal rates, based on either 13C-leucine or 13C-alpha-ketoisocaproic acid (KIC) enrichments, and glucose turnover rate were not significantly different between malnourished patients and controls. Moreover, glutamine turnover was increased by 28% in malnourished patients as compared with normal volunteers (429.8 +/- 86.8 v 334.9 +/- 15.9 mumol/kg/h, P = .02). These results suggest that hypometabolic adaptation, although previously documented in starved volunteers, is not operative during states of chronic malnutrition due to gastrointestinal disease. The increase in glutamine turnover rate might represent an adaptative mechanism to malnutrition for preservation of visceral mass or function.

Glutamine metabolism in children with short-bowel syndrome: a stable isotope study.

Because glutamine is thought to be a major fuel for developing gut, we tested the hypothesis that extensive small-bowel resection alters whole-body glutamine metabolism in vivo. Eleven infants and children who had undergone extensive small intestinal resection (residual bowel length: 35 +/- 13 cm; mean +/- SD) and four control infants received 4-h primed, continuous i.v. infusions of L-[(1-13C]leucine and L-[2-15N]glutamine in the postabsorptive state. The appearance rates of glutamine and leucine into plasma were determined from stable isotope enrichments in plasma at steady state. We observed the following: 1) Regardless of intestinal status, leucine and glutamine fluxes were higher in infants than values previously reported for adults. 2) Small-bowel resection was associated with a reduction in glutamine appearance rate (568 +/- 124 mumol.kg lean body mass-1.h-1 in short-bowel syndrome infants versus 816 +/- 149 mumol.kg lean body mass-1.h-1 in control infants; p < 0.05). 3) In contrast, leucine appearance rate was unaltered in short-bowel syndrome patients. The findings suggest that the small intestine plays a prominent role in glutamine metabolism in human infants.

Glutamine metabolism in healthy adult men: response to enteral and intravenous feeding.

To assess the effect of feeding on glutamine kinetics, six healthy men received 4-h intravenous infusions of L-[2-15N]glutamine and L-[1-13C]leucine on 3 separate days: 1) in the postabsorptive state, 2) over the course of an 8-h nasogastric infusion of a small peptide-based nutrient mixture, and 3) during an 8-h isonitrogenous, isoenergetic intravenous infusion (1.5 g amino acid.kg-1.d-1; 130 kJ.kg-1.d-1, or 31 kcal.kg-1.d-1; 58% carbohydrate and 42% fat). Regardless of the route, nutrition increased leucine appearance rate (Ra) and oxidation, stimulated protein synthesis, and improved leucine balance; apparent rates of protein breakdown decreased during enteral nutrition only. Glutamine Ra increased 16.8% (NS) and 26.2% (P < 0.01) with parenteral and enteral feeding, respectively, over postabsorptive values. The present findings are consistent with a major role of glutamine in interorgan nitrogen transport in the fed state and further suggest that increased availability of precursors may stimulate glutamine synthesis de novo, and enteral infusion of peptide-bound amino acids may be an effective route to provide free glutamine to the rest of the body.

Leucine metabolism at graded amino acid intakes in children receiving parenteral nutrition.

To assess the response of protein turnover to graded levels of amino acid (AA) intakes, leucine kinetics were determined in six 8- to 16-yr-old patients in a stable nutritional status receiving home parenteral nutrition (PN) for short-bowel syndrome or intestinal pseudo-obstruction syndrome. Although daily energy intake was kept constant at 68.7 +/- 13 kcal/kg lean body mass (LBM) with 25.4 +/- 3.6% lipid, patients were given, for three consecutive 7-day periods, 0.7, 1.5, or 2.5 g AA.kg LBM-1.day-1, with the order of the regimens being randomized. On day 7 of each period, a 4-h infusion of L-[1-13C]leucine was performed during intravenous feeding; plasma [13C]ketoisocaproate and expired 13CO2 enrichments were used to assess whole body leucine turnover (Ra), oxidation rate (Ox), nonoxidative disposal [an estimate of protein synthesis (S)], and leucine derived from protein breakdown (B). Urine collection (24 h) was performed for determination of nitrogen excretion. Results indicate a dose-dependent rise in plasma leucine concentration, Ra, and Ox but no significant change in B. There was a significant increase of S (P = 0.04 analysis of variance) with increased AA intakes as well as net leucine balance (P = 0.02). Results are consistent with improved leucine balance, when leucine intake increases, despite increased leucine oxidation. The net protein gain observed with higher AA intakes may suggest a beneficial effect for children receiving long-term PN.

[15N]- and [14C]glutamine fluxes across rabbit ileum in experimental bacterial diarrhea.

L-Glutamine (Gln) fluxes and the effects of Gln on Na and Cl transport were studied across the ileum of healthy and rabbit diarrheagenic Escherichia coli (RDEC-1)-infected weanling rabbits. Stable ([alpha-15N]Gln) and radioisotopic ([U-14C]Gln) tracers provided identical estimates of Gln transport both in healthy (H) and infected (I) rabbits. RDEC-1 infection, however, decreased net Gln flux [Jnet[14C]Gln = 682 +/- 147 (H) vs. 278 +/- 63 (I); Jnet[15N]Gln = 739 +/- 160 vs. 225 +/- 110 nmol.h-1.cm-2] due to a reduction in mucosal-to-serosal flux. After addition of Gln, increases in net Na absorption [delta Jnet[15N]Gln = 1.87 +/- 0.45 (H) vs. 0.70 +/- 0.27 (I) microeq.h-1.cm-2] and short-circuit current (delta Isc) [1.80 +/- 0.40 (H) vs. 0.74 +/- 0.14 (I) microeq.h-1.cm-2] were also reduced in infected rabbits. Addition of glucose after Gln, however, stimulated Na absorption further. These results indicate that 1) Gln is actively absorbed as intact Gln molecule across rabbit ileum; 2) Gln stimulates an electrogenic Na absorption in a 1:2 ratio that may be further stimulated by glucose; and 3) in RDEC-1 infection electroneutral NaCl absorption, intact Gln absorption, and electrogenic stimulation of Na absorption by glutamine are reduced.

Urinary excretion of iodide and fluoride from supplemented food grade salt.

Iodide and fluoride supplemented food grade salt (NaCl) is a common source of these two micronutrients. In a pilot study, we investigated whether increased intake of NaCl supplemented with iodide (I-) and fluoride (F-) results in their higher bioavailability. Twelve healthy adult human volunteers ingested increasing quantities (1, 3, 6 and 9 g) of NaCl with usual diet over 8 days. Sodium (Na+), I- and F- were measured in 24 hour urine specimen. During the 4 day basal period when no additional NaCl was ingested, ingestion of NaCl calculated from urinary Na+ concentration and diuresis was 8.25 +/- 0.67 g/24 h. During the same period 0.11 +/- 0.01 and 0.61 +/- 0.04 mg of I- and F- respectively were excreted in the urine per 24 h. Increased ingestion of supplemented NaCl resulted in higher urinary excretion of sodium while urinary creatinine remained stable. 92% of I- and 40% of F- contained in the additional amount of NaCl ingested were excreted in the urine. These results indicate that with increased ingestion of supplemented (I- and F-) NaCl, almost the totality of I- is excreted in the urine while fluoride is either incompletely absorbed or retained by the body to a higher extent. I- and F- supplemented NaCl is, therefore, an effective vehicle to provide these micronutrients when ingested with diet.

Glutamine nitrogen kinetics in insulin-dependent diabetic humans.

To assess the effect of insulin deficiency on whole body glutamine kinetics, five young adults with type I (insulin-dependent) diabetes received 4-h primed continuous infusions of L-[1-13C]leucine and L-[2-15N]glutamine in the postabsorptive state after blood glucose had been clamped overnight at either a normoglycemic level (approximately 85 mg/dl) or a moderate hyperglycemic level (approximately 260 mg/dl) by means of an automated glucose control insulin infusion system. The hyperglycemic state was associated with a significant rise in leucine level [from 165 +/- 23 to 242 +/- 62 (SD) microM], appearance rate (from 125 +/- 11 to 142 +/- 17 mumol.kg-1.h-1), and oxidation (from 27 +/- 10 to 31 +/- 10 mumol.kg-1.h-1). In contrast, neither the plasma level nor the appearance rate of glutamine (333 +/- 51 vs. 318 +/- 58 mumol.kg-1.h-1) was affected. We conclude that insulin deficiency resulting in moderate hyperglycemia induces a 13% rise in whole body proteolysis and yet does not stimulate glutamine de novo synthesis, despite increased precursor availability.

Intestinal absorption of free oral hyperalimentation in the very short bowel syndrome.

Ten adult ambulatory patients with the nonactive digestive disease short bowel syndrome were prospectively studied to quantitatively assess their free oral intake and their net digestive absorption of total calories, fat, protein, and carbohydrate during a 3-day period at least 6 months after a resection. The remaining portions of small bowel had a mean length of 75 cm (range, 0-200 cm); the remaining colon lengths had a mean of 67% of normal (range, 0%-100%). The experimental diets were formulated according to a home dietary inquiry. During the study period, pooled intakes and digestive losses were measured for total calories, fat, and protein using the bomb calorimetry, Van de Kamer, and Kjeldahl techniques, respectively. The ingested diet provided 58 +/- 14 kcal.kg-1.day-1 (mean +/- SD) and consisted of 46% carbohydrate, 31% fat, and 23% protein. Net digestive absorption was 67% +/- 12% for total calories, 79% +/- 15% for carbohydrate, 52% +/- 16% for fat, and 61% +/- 19% for protein. The larger net digestive absorption of carbohydrate (P less than or equal to 0.004) compared with fat and protein suggests salvage of colonic cholesterol in short bowel syndrome patients. It is concluded that these patients with the short bowel syndrome adapted to a hypercaloric, hyperprotein diet to compensate for increased fecal losses and that this hyperphagia does not seem to have impaired their net digestive absorption.

Absorption and metabolic effects of enterally administered glutamine in humans.

To assess absorption and metabolic effects of enterally delivered glutamine, a total of 10 healthy subjects received perfusions of natural L-glutamine at graded infusion rates (ranging from 0 to 126 mmol/h; n = 2-8 subjects at each rate) along with a nonabsorbable marker (polyethylene glycol) through a double-lumen nasojejunal tube. Perfusions were administered after an overnight fast during three consecutive 1- or 2.5-h periods and in a randomized order. In eight subjects, continuous intravenous infusion of D-[6,6-2H2]glucose, L-[1-13C]leucine, and L-[15N]alanine was simultaneously performed. Glutamine was nearly quantitatively absorbed over the 30-cm study segment; estimated Km and Vmax of glutamine absorption were 2.48 and 2.32 mmol/min over the 30-cm study segment. Enteral glutamine administration induced 1) a dose-dependent increase in plasma glutamine level; 2) a rise in the plasma level and appearance rate (Ra) of alanine (from 191 +/- 42 to 213 +/- 51 mumols.kg-1.h-1, P less than 0.05, for 0 and 46.8-mmol/h glutamine infusion rates, respectively) and in plasma levels of glutamate, citrulline, aspartate, and urea; 3) a decline in plasma free fatty acid and glycerol levels; and 4) no change in leucine or glucose Ra. We conclude that glutamine is efficiently absorbed by human jejunum in vivo and may directly inhibit lipolysis, whereas it neither affects proteolysis nor glucose production in healthy postabsorptive humans.

Use of a ventilated canopy for assessment of [13C]leucine oxidation in patients receiving total parenteral nutrition.

Rates of oxidation of infused 13C-labeled substrates are calculated from CO2 production and 13C enrichment in breath CO2. Breath sampling through a mouthpiece is not appropriate in severely ill patients; the authors therefore validated the use of direct air sampling from the ventilated canopy of an indirect calorimeter for measuring the oxidation of 13C-labeled substrates. Infusions of H13CO3Na or L-[1-13C]leucine were performed in four healthy postabsorptive adults and six malnourished patients receiving total parenteral nutrition (TPN). At each sampling point, air was collected from the canopy to compare with breath air sampled through a mouthpiece and 13CO2 enrichment determined by isotope ratio mass spectrometry. Despite five-fold dilution of expired air by room air within the canopy (a dilution required to maintain safe CO2 levels in inspired air): (1) Breath 13CO2 enrichment was accurately predicted using samples from the canopy, with a correction taking into account the measured CO2 fractions in canopy and room air; (2) the precision in isotopic determination was similar with both methods (SD/mean of 12 determinations = 2.5 +/- 1.0% vs 3.0 +/- 1.0%). These data demonstrate that the use of a ventilated canopy allows for combined assessment of energy expenditure and rates of oxidation of 13C-labeled substrates even in sick, debilitated patients receiving total parenteral nutrition.

Glutamine metabolism after small intestinal resection in humans.

Glutamine and leucine kinetics were measured using stable isotopes in five enterectomized patients (residual small bowel, 80 +/- 25 cm [mean +/- SE]) who were in a near normal nutritional status at distance from surgery. While parameters of leucine metabolism were normal, rates of whole body glutamine utilization were reduced by 20% in the patients. The data suggest that the small intestine plays a prominent role in glutamine utilization in vivo in humans.

Intestinal absorption of amiodarone in man.

The jejunal absorption rate of amiodarone and the influence of lipids on it were studied in human volunteers using the intestinal perfusion technique. A nutrient solution (Realmentyl, Sopharga Laboratories, France) with 300 mg of the drug was infused for 120 minutes at the ligament of Treitz. The segment tested was 25 cm long. Two caloric loads of the nutrient solution, 3.3 Kcal/min (solution A) and 1.3 Kcal/min (solution B), A containing total lipid and caloric load 2.5 times higher than B, were administered. Minor interindividual differences in amiodarone absorption rate were observed (20.2 to 31.7%) with solution A. Amiodarone absorption correlated with lipid absorption significantly. Since the maximal plasma concentrations of the drug and the area under the curve (AUC/24 hours) did not correlate with the amount of amiodarone absorbed, the wide fluctuations of amiodarone pharmacokinetics must mainly be due to amiodarone tissue distribution and metabolic pathway.