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Vasoactive intestinal polypeptide modulates GABAA receptor function through activation of cyclic AMP.

Vasoactive intestinal polypeptide (VIP) has been shown to potentiate current responses elicited by activation of the GABAA receptor (IGABA) in freshly dissociated ganglion cells of the rat retina. Here we tested the hypothesis that this heteroreceptor cross talk is mediated by an intracellular cascade of events that includes the sequential activation of a stimulatory guanine nucleotide binding (Gs) protein and adenylate cyclase, the subsequent increase in levels of cyclic AMP and, finally, the action of the cyclic AMP-dependent protein kinase (PKA). Intracellular dialysis of freshly dissociated ganglion cells with GTP gamma s irreversibly potentiated IGABA, while GDP beta s either decreased or had no effect on IGABA. Additionally, GDP beta s blocked the potentiation of IGABA by VIP. Cholera toxin rendered VIP ineffective in potentiating IGABA, while pertussis toxin had no effect on the VIP-induced potentiation of IGABA. Extracellular application of either forskolin or 8-bromo-cyclic AMP potentiated IGABA, as did the introduction of cyclic AMP directly into the intracellular compartment through the recording pipet. Intracellular application of cyclic AMP-dependent protein kinase (PKA) potentiated IGABA, while a PKA inhibitor blocked the potentiating effect of VIP. These results lead us to conclude that activation of a cyclic AMP-dependent second-messenger system mediates the modulation of GABAA receptor function by VIP in retinal ganglion cells.

Animals↗

Different beta-subunits determine G-protein interaction with transmembrane receptors.

Regulatory GTP-binding proteins (G proteins) are membrane-attached heterotrimers (alpha, beta, gamma) that mediate cellular responses to a wide variety of extracellular stimuli. They undergo a cycle of guanine-nucleotide exchange and GTP hydrolysis, during which they dissociate into alpha-subunit and beta gamma complex. The roles of G-protein alpha-subunits in these processes and for the specificity of signal transduction are largely established; the beta- and gamma-subunits are essential for receptor-induced G-protein activation and seem to be less diverse and less specific. Although the complementary DNAs for several beta-subunits have been cloned, isolated subunits have only been studied as beta gamma complexes. Functional differences have been ascribed to the gamma-subunit on the basis of extensive sequence similarity among beta-subunits and apparent heterogeneity in gamma-subunit sequences. Beta gamma complexes can interact directly or indirectly with different effectors. They seem to be interchangeable in their interaction with pertussis toxin-sensitive alpha-subunits, so we tested this by microinjecting antisense oligonucleotides into nuclei of a rat pituitary cell line to suppress the synthesis of individual beta-subunits selectively. Here we show that two out of four subtypes of beta-subunits tested (beta 1 and beta 3) are selectively involved in the signal transduction cascades from muscarinic M4 (ref. 4) and somatostatin receptors, respectively, to voltage-dependent Ca2+ channels.

Animals↗

Cytokine-induced expression of tPA is differentially modulated by NO and ROS in rat mesangial cells.

BACKGROUND: Dysregulated expression of diverse proteases and their specific inhibitors is critical for the increase in extracellular matrix accumulation that accompanies chronic inflammatory and sclerotic processes within the renal mesangium. Within the activating cascade of several proteases, the plasminogen system plays an important role. METHODS: We tested for modulatory effects of the nitric oxide (NO) donors S-nitroso-N-acetyl-D,L-penicillamine and DETA-NONOate, and the superoxide-generating system hypoxanthine/xanthine oxidase (HXXO) on the expression and activity of tissue plasminogen activator (tPA) by ELISA and Northern blotting. RESULTS: Interleukin-1beta (IL-1beta)-induced tPA and plasminogen activator inhibitor (PAI)-1 mRNA and supernatant tPA antigen were significantly inhibited by both NO donors, which resulted in a net decrease in the IL-1beta-evoked tPA enzyme activity in the conditioned media. Addition of the NO-synthase inhibitor N-monomethyl l-arginine markedly increased the cytokine-triggered tPA- and PAI-1 mRNA levels, respectively. In contrast, HXXO caused a marked amplification of the IL-1beta-induced steady-state tPA mRNA level and tPA enzyme activity that was blocked by catalase. Since MnTBAP, a superoxide dismutase mimetic, had no effects on the amplification of mRNA levels, we suggest that H2O2 is the candidate reactive oxygen species (ROS) responsible for the potentiation of IL-1beta-triggered tPA and PAI-1 expression. CONCLUSIONS: The temporal relationship between NO and ROS generation is a critical step in the modulation of tPA and PAI-1 expression in mesangial cells and may account for a dysregulation of matrix turnover during inflammatory processes in the renal mesangium.

Animals↗

Neuroprotective potential of a viral vector system induced by a neurological insult.

Gene transfer into neurons via viral vectors for protection against acute necrotic insults has generated considerable interest. Most studies have used constitutive vector systems, limiting the ability to control transgene expression in a dose-dependent, time-dependent, or reversible manner. We have constructed defective herpes simplex virus vectors designed to be induced by necrotic neurological insults themselves. Such vectors contain a synthetic glucocorticoid-responsive promoter, taking advantage of the almost uniquely high levels of glucocorticoids-adrenal stress steroids-secreted in response to such insults. We observed dose-responsive and steroid-specific induction by endogenous and synthetic glucocorticoids in hippocampal cultures. Induction was likely to be rapid enough to allow transgenic manipulation of relatively early steps in the cascade of necrotic neuron death. The protective potential of such a vector was tested by inclusion of a neuroprotective transgene (the Glut-1 glucose transporter). Induction of this vector by glucocorticoids decreased glutamatergic excitotoxicity in culture. Finally, both exogenous glucocorticoids and excitotoxic seizures induced reporter gene expression driven from a glucocorticoid-responsive herpes simplex virus vector in the hippocampus in vivo.

Animals↗

What are the instrumentation requirements for measuring the isotopic composition of net ecosystem exchange of CO2 using eddy covariance methods?

Better quantification of isotope ratios of atmosphere-ecosystem exchange of CO2 could substantially improve our ability to probe underlying physiological and ecological mechanisms controlling ecosystem carbon exchange, but the ability to make long-term continuous measurements of isotope ratios of exchange fluxes has been limited by measurement difficulties. In particular, direct eddy covariance methods have not yet been used for measuring the isotopic composition of ecosystem fluxes. In this article, we explore the feasibility of such measurements by (a) proposing a general criterion for judging whether a sensor's performance is sufficient for making such measurements (the criterion is met when the contribution of sensor error to the flux measurement error is comparable to or less than the contribution of meteorological noise inherently associated with turbulence flux measurements); (b) using data-based numerical simulations to quantify the level of sensor precision and stability required to meet this criterion for making direct eddy covariance measurements of the 13C/12C ratio of CO2 fluxes above a specific ecosystem (a mid-latitude temperate forest in central Massachusetts, USA); (c) testing whether the performance of a new sensor-a prototype pulsed quantum cascade laser (QCL) based isotope-ratio absorption spectrometer (and plausible improvements thereon)-is sufficient for meeting the criterion in this ecosystem. We found that the error contribution from a prototype sensor (approximately 0.2 per thousand, 1 SD of 10 s integrations) to total isoflux measurement error was comparable to (1.5 to 2x) the irreducible 'meteorological' noise inherently associated with turbulent flux measurements above this ecosystem (daytime measurement error SD of approximately 60% of flux versus meteorological noise of 30-40% for instantaneous half-hour fluxes). Our analysis also shows that plausible instrument improvements (increase of sensor precision to approximately 0.1 per thousand, 1 SD of 10 s integrations, and increased sensor stability during the half-hour needed to integrate eddy covariance measurements) should decrease the contribution of sensor error to the point where it is less than the contribution from meteorological noise. This suggests that new sensors using QCL-based isotope ratio absorption spectroscopy should make continuous long-term observations of the isotopic composition of CO2 fluxes via eddy covariance methods feasible.

Carbon Dioxide↗

Intracranial renin alters gustatory neural responses in the nucleus of the solitary tract of rats.

Activation of the renin-angiotensin system in the brain is considered important in the arousal and expression of sodium appetite. To clarify the effects of directly activating this hormonal cascade, taste neurons in the nucleus of the solitary tract of rats were tested with a battery of sapid stimuli after intracerebroventricular injection of renin or its vehicle. The rats were chronically prepared but lightly anesthetized during the recording procedure. Eighty-five taste neurons were tested: 46 after renin injections and 39 after vehicle. Neural activity was counted for 5.0-s periods without stimulation (spontaneous) and during stimulation with water and sapid chemicals. The averaged responses to each of the standard stimuli (0.1 M NaCl, 0.3 M sucrose, 0.01 M citric acid, and 0.01 M quinine hydrochloride) did not differ significantly between the two conditions. When the rats were tested with a concentration range of NaCl, however, after renin the average responses to the hypertonic 0.3 and 1.0 M stimuli were reduced to 74 and 70%, respectively, compared with those after vehicle injections. A similar tendency was evident for the subsample of neurons that responded best to NaCl, but the effect was smaller. These data are consistent with, but not as dramatic as, those reported after dietary-induced sodium appetite.

Animals↗

Conceptual and practical issues in the pharmacological treatment of brain injury.

It is only within the last ten years that research on treatment for central nervous system (CNS) recovery after injury has become more focused on the complexities involved in promoting recovery from brain injury when the CNS is viewed as an integrated and dynamic system. There have been major advances in research in recovery over the last decade, including new information on the mechanics and genetics of metabolism and chemical activity, the definition of excitotoxic effects and the discovery that the brain itself secretes complex proteins, peptides and hormones which are capable of directly stimulating the repair of damaged neurons or blocking some of the degenerative processes caused by the injury cascade. Many of these agents, plus other nontoxic naturally occurring substances, are being tested as treatment for brain injury. Further work is needed to determine appropriate combinations of treatments and optimum times of administration with respect to the time course of the CNS disorder. In order to understand the mechanisms that mediate traumatic brain injury and repair, there must be a merging of findings from neurochemical studies with data from intensive behavioral testing.

Animals↗

TGFbeta2 mediates the effects of hedgehog on hypertrophic differentiation and PTHrP expression.

The development of endochondral bones requires the coordination of signals from several cell types within the cartilage rudiment. A signaling cascade involving Indian hedgehog (Ihh) and parathyroid hormone related peptide (PTHrP) has been described in which hypertrophic differentiation is limited by a signal secreted from chondrocytes as they become committed to hypertrophy. In this negative-feedback loop, Ihh inhibits hypertrophic differentiation by regulating the expression of Pthrp, which in turn acts directly on chondrocytes in the growth plate that express the PTH/PTHrP receptor. Previously, we have shown that PTHrP also acts downstream of transforming growth factor beta (TGFbeta) in a common signaling cascade to regulate hypertrophic differentiation in embryonic mouse metatarsal organ cultures. As members of the TGFbeta superfamily have been shown to mediate the effects of Hedgehog in several developmental systems, we proposed a model where TGFbeta acts downstream of Ihh and upstream of PTHrP in a cascade of signals that regulate hypertrophic differentiation in the growth plate. This report tests the hypothesis that TGFbeta signaling is required for the effects of Hedgehog on hypertrophic differentiation and expression of PTHRP: We show that Sonic hedgehog (Shh), a functional substitute for Ihh, stimulates expression of Tgfb2 and Tgfb3 mRNA in the perichondrium of embryonic mouse metatarsal bones grown in organ cultures and that TGFbeta signaling in the perichondrium is required for inhibition of differentiation and regulation of Pthrp expression by Shh. The effects of Shh are specifically dependent on TGFbeta2, as cultures from Tgfb3-null embryos respond to Shh but cultures from Tgfb2-null embryos do not. Taken together, these data suggest that TGFbeta2 acts as a signal relay between Ihh and PTHrP in the regulation of cartilage hypertrophic differentiation.

Animals↗

IP(3) receptor function and localization in myotubes: an unexplored Ca(2+) signaling pathway in skeletal muscle.

We present evidence for an unexplored inositol 1,4,5-trisphosphate-mediated Ca(2+) signaling pathway in skeletal muscle. RT-PCR methods confirm expression of all three known isotypes of the inositol trisphosphate receptor in cultured rodent muscle. Confocal microscopy of cultured mouse muscle, doubly labeled for inositol receptor type 1 and proteins of known distribution, reveals that the receptors are localized to the I band of the sarcoplasmic reticulum, and this staining is continuous with staining of the nuclear envelope region. These results suggest that the receptors are positioned to mediate a slowly propagating Ca(2+) wave that follows the fast Ca(2+) transient upon K(+) depolarization. This slow wave, imaged using fluo-3, resulted in an increase in nucleoplasmic Ca(2+) lasting tens of seconds, but not contraction; the slow wave was blocked by both the inositol trisphosphate receptor inhibitor 2-aminoethoxydiphenyl borate and the phospholipase C inhibitor U-73122. To test the hypothesis that these slow Ca(2+) signals are involved in signal cascades leading to regulation of gene expression, we assayed for early effects of K(+) depolarization on mitogen-activated protein kinases, specifically extracellular-signal related kinases 1 and 2 and the transcription factor cAMP response element-binding protein (CREB). Within 30-60 seconds following depolarization, phosphorylation of both the kinases and CREB was evident and could be inhibited by 2-aminoethoxydiphenyl borate. These results suggest a signaling system mediated by Ca(2+) and inositol trisphosphate that could regulate gene expression in muscle cells.

Actinin↗

Alkyl-lysophospholipids activate the SAPK/JNK pathway and enhance radiation-induced apoptosis.

Alkyl-lysophospholipids (ALPs) represent a new class of antitumor drugs that induce apoptotic cell death in a variety of tumor cell lines. Although their precise mechanism of action is unknown, ALPs primarily act on the cell membrane, where they inhibit signaling through the mitogen-activated protein kinase (MAPK) pathway. Because stimulation of the stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK) pathway is essential for radiation-induced apoptosis in certain cell types, we tested the effect of ALPs in combination with ionizing radiation on MAPK/SAPK signaling and apoptosis induction. Here, we present data showing that three ALPs, 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine, hexadecylphosphocholine, and the novel compound octadecyl-(1,1-dimethyl-piperidinio-4-yl)-phosphate (D-21266) induce time- and dose-dependent apoptosis in the human leukemia cell lines U937 and Jurkat T but not in normal vascular endothelial cells. Moreover, in combination with radiation, ALPs strongly enhance the induction of apoptosis in both leukemic cell lines. All tested ALPs not only prevented MAPK activation, but, like radiation, stimulated the SAPK/JNK cascade within minutes. A dominant-negative mutant of c-Jun inhibited radiation- and ALP-induced apoptosis, indicating a requirement for the SAPK/JNK pathway. Our data support the view that ALPs and ionizing radiation cause an enhanced apoptotic effect by modulating the balance between the mitogenic, antiapoptotic MAPK, and the apoptotic SAPK/JNK pathways. This type of modulation of specific signal transduction pathways in tumor cells may lead to the development of new therapeutic strategies.

Apoptosis↗

[Genetic bases of human sex determination and differentiation].

Male and female sex determination depends on Y-linked SRY gene activity. This gene initiates the cascade of reactions which lead to the differentiation of bipotential, indifferent gonads to testes or ovaries, depending on the presence or absence of active from SRY. Since SRY discovery in 1990, several new genes playing important role in gonadal and in both internal and external genitalia development and differentiation have been identified. Detailed knowledge concerning above mentioned genes will enhance our understanding of etiology of sexual development abnormalities.

Embryonic and Fetal Development↗

Inhibiting effects of low-molecular weight heparin and adrenocortical hormone on hemolysis of red cells in patients with paroxysmal nocturnal hemoglobinuria in vitro.

OBJECTIVE: To study the effects of low-molecular weight heparin (LMWH) and adrenocortical hormone (dexamethasone) on the hemolysis of red cells of patients with paroxysmal nocturnal hemoglobinuria (PNH) in vitro. METHODS: Using Ham's test and micro-complement lysis sensitive test (mCLST), the changes in hemolysis of red cells from 6 typical PNH cases were examined after adding LMWH and dexamethasone in different concentrations into the test solution in vitro. The effects of LMWH and dexamethasone on the coagulation of the tested blood samples were also studied using the activated partial thromboplastin time (APTT) test. RESULTS: Both LMWH and dexamethasone inhibited the hemolysis of PNH red cells, and they also showed a synergistic effect. The inhibiting effects were dose-dependent. Moreover, a tolerable dose of LMWH induced a limited prolongation of APTT. Dexamethasone showed two possible mechanisms in the inhibition of PNH red cells hemolysis through Ham's test and mCLST, respectively: (1) inhibiting both antibodies binding to red cells and (2) the initiation of the activation of complement 3 (C3). LMWH could inhibit hemolysis as determined by both Ham's test and mCLST, which indicated that LMWH could block the activation of complement cascade. CONCLUSIONS: Both LMWH and dexamethasone could inhibit hemolysis in PNH, and they showed a synergistic effect. Their mechanisms of inhibiting hemolysis differed from each other. Furthermore, a tolerable dose of LMWH induced a limited prolongation of APTT. LMWH might be useful for controlling acute hemolysis in patients with PNH and reducing the dose of adrenocortical hormone.

Dexamethasone↗

New trends in anticoagulant therapy.

Classic anticoagulant drugs, such as heparin and warfarin, are very effective. However, although in use for more than 50 years, they do have some clinical drawbacks. Heparin, now better termed unfractionated heparin, can only be used intravenously and its laboratory control is complicated. Warfarin is orally administered, but its therapeutic window is very narrow and patients need repeated laboratory tests. Moreover, both drugs are non-specific, as they inhibit the coagulation cascade at several steps. Pharmaceutic research has developed new drugs, some of which are already on the market, such as fondaparinux, a pentasaccharide that can interact with antithrombin, thus inhibiting factor Xa. This pentasaccharide is part of the parent heparin molecule and can be chemically synthesized, with the advantage of avoiding extractive compounds. Fondaparinux has a half-life compatible with once-a-day administration; modification of its structure (idraparinux) has led to more stable binding with antithrombin and to an increase in its half-life to allow once-a-week administration. Alternatives to oral anticoagulants have been developed following the study of some compounds like hirudin, which directly binds thrombin and blocks its catalytic site. One of these molecules, ximelagatran, is in advanced clinical development. Ximelagatran is converted into its active form, melagatran, in the circulation, and thrombin activity can be blocked by oral administration twice daily. There is no need for laboratory control and phase II and phase III studies are encouraging. The next few years should bring great changes to the treatment of patients with thromboembolic disorders.

Anticoagulants↗

Expression regulation of MAO isoforms in monocytic cells in response to Th2 cytokines.

BACKGROUND: Th2-cytokines, such as interleukins-4 and -13 (IL-4, IL-13), have been identified as alternative stimuli of monocytes/macrophages. We have recently profiled the gene-expression pattern of IL-4-treated human peripheral monocytes and found that 15-lipoxygenase-1 (15-LOX1) and monoamine oxidase A (MAO-A) are among the five most strongly upregulated gene products in IL-4-treated cells. Transfection of monocytic cells (U937) with 15-LOX1 also induced MAO-A expression. These data suggested that 15-LOX1 products might play a role in the IL4-induced signaling cascade leading to expression of MAO-A in human monocytes. MATERIAL/METHODS: To test this hypothesis we incubated wild-type and 15-LOX1-transfected U937 cells with different concentrations of either IL-4 or 15-LOX-products [13S-H(p)ODE, 15S-H(p)ETE] and quantified the expression of 15-LOX1, MAO-A, and MAO-B by activity assays and real-time RT-PCR. RESULTS: Wild-type U937 cells express neither MAO-A nor MAO-B, but after three days of IL4 treatment, MAO-A mRNA was detected. A similar isoform-specific expression of MAO-A mRNA was observed when U937 cells were transfected with 15-LOX1 or when the cells were incubated with primary 15-LOX1 products (hydroperoxy fatty acids) or H2O2. In contrast, the corresponding hydroxy fatty acids were ineffective. CONCLUSIONS: These data indicate that increased intracellular peroxide concentrations (oxidative stress) induce MAO-A expression in monocytes/macrophages, which normally do not express the enzyme. Our findings also suggest that IL-4-induced upregulation of MAO-A expression in human peripheral monocytes may proceed via 15-LOX1-dependent and 15-LOX1-independent pathways. The biological role of MAO-A expression for monocyte function is discussed.

Arachidonate 15-Lipoxygenase↗

In vitro inhalation behaviour and therapeutical response of salbutamol particles administered from two metered dose aerosols.

In this study the particle size, as well as the in vitro deposition and the immediate bronchodilating effect on asthmatic patients, of two salbutamol inhalation aerosol preparations (Ventoline, Glaxo, UK, and salbutamol inhalation aerosol, Orion Pharmaceutica, Finland) were compared. The in vitro deposition study was performed using the modified Sierra Andersen cascade impactor. The bronchodilating effect of inhaled aerosol doses were monitored by measuring peak expiratory flow (PEF) values. In the clinical study, the pulse and blood pressure of the patients, as well as the side effects, were also recorded. Due to the anatomy and physiology of human lungs, the accepted optimum size for inhaled drug particles is under 5 microns, and preferably under 2 microns. Over 95% of the drug particles in both aerosol preparations were under 5 microns. 30% of the salbutamol particles in the Ventoline inhalation aerosol were under 2 microns, whereas in Orion salbutamol aerosol 14% of the drug particles were under 2 microns. Respectively 23% of Ventoline and 19% of the Orion salbutamol preparation penetrated into the therapeutically most significant imitated alveolar stages of the modified cascade impactor. Both salbutamol aerosols showed a clear clinical efficacy in the bronchodilating test. In addition, no significant differences existed in the bronchodilating effect of these inhalation aerosols. In conclusion, although there seemed to be a slight difference in the particle size distribution and in the in vitro inhalation behaviour, this variation did not have any effect on the clinical response.

Adult↗

[Prostaglandins and prostaglandin analogs: experimental studies on their effect of tumor metastasis].

Metastatic tumor spread is regarded as the highest degree of malignancy of tumors and generally determines the prognosis. Before clinically detectable metastases are evident in distant organs, tumor cells interact with cellular and non-cellular components of the host as they complete the multistep process referred to as the metastatic cascade. Many investigational drugs acting at different levels of the metastatic process were tested for beneficial effects on metastasis. Because of the influence of prostaglandins on host components essential for tumor metastasis, this group of a compounds was tested in model of tumor growth and metastasis. Prostaglandins of the E, D and J series inhibit growth of variety of tumor cells and cause a reduction of primary tumor growth in vivo. The antiproliferative action of prostaglandins of the E series seems to be related to an induction of differentiation, whereas prostaglandins of the D and J series mediate growth inhibition by a blockade of the cell cycle and an inhibition of RNA and DNA synthesis. There is no conclusive evidence that prostaglandins of the E, D and J series may specifically interfere with mechanisms of tumor metastasis. In contrast to the prostaglandins of the E, D and J series, prostacyclin has been shown to inhibit several processes involved in tumor metastasis, but without exerting a direct cytotoxic effect on tumor cells. Our own studies have shown that Cicaprost, a stable prostacyclin analogue, prevents metastasis if given continuously from the day of tumor implantation, and is also effective in reducing metastasis if treatment is begun following surgical removal of the primary tumor, when micrometastases are already present.

Animals↗

An immnosuppressive drug, cyclosporine-A acts like anti-depressant for rats under unpredictable chronic stress.

Rats were subjected to unpredictable chronic stress (UCS), which was composed of 3 cycles of 7 kinds of stress for 21 days. Rats given UCS exhibited a depressive state in behavioral tests such as emergence tests and forced swim tests. Administration of cyclosporine-A (CsA), an immunosuppressive drug, gave rise to antidepressant effect in rats under the UCS, but not in stress-free rats. In other words, CsA shortened both the latency time in emergence tests and the immobility time in forced swim tests in rats given UCS. Analysis of brain tissue by HPLC revealed that CsA caused a significant increase in NE, 5-HT and 5-HIAA levels in the cortex of UCS treated rats, but treatment with either UCS or CsA alone resulted in the opposite effect. Comparing the data of monoamines and their metabolites in the brain, cascades may be different between CsA and imipramine, although both of them showed antidepressive effect in behavioral tests.

Adrenal Glands↗

13C-egg white breath test: a non-invasive test of pancreatic trypsin activity in the small intestine.

BACKGROUND: The recent availability of egg white protein highly enriched with (13)C has allowed breath test technology to be adapted for the study of protein digestion and absorption. Pancreatic trypsin is considered to be the key enzyme in the proteolytic cascade. AIM: To evaluate trypsin activity in the small intestine of healthy volunteers and patients with pancreatic disease by a recently developed (13)C-egg white breath test. METHODS: A total of 48 healthy volunteers and 30 patients with pancreatic disease were studied after ingestion of a test meal consisting of 22 g (13)C-labelled egg protein. Breath samples were taken before and after ingestion of the meal and analysed for (13)CO(2) concentration. Moreover, pancreatic trypsin output after maximal stimulation was measured in 13 patients and nine healthy volunteers. RESULTS: The six hour cumulative (13)CO(2) excretion in breath was significantly lower in patients than controls (mean (SEM): 6.23 (0.82)% v 19.16 (0. 58)%, p<0.0001). An excellent correlation was found between the six hour cumulative (13)CO(2) excretion and trypsin activity after maximal pancreatic stimulation. CONCLUSION: The non-invasive (13)C-egg white breath test is promising as an indirect pancreatic proteolytic function test.

Adult↗