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R Schreiber

Publications and source records attributed to R Schreiber.

At least 55 records · Page 3Linked to original sources

The Agamma-195 (C-->G) mutation in hereditary persistence of fetal hemoglobin is not associated with activation of a reporter gene in vitro.

Hereditary persistence of fetal hemoglobin is an uncommon, benign disorder in which the expression of gamma-globin genes persists into adult life. Several point mutations have been associated with the increased gamma-globin gene promoter activity. We evaluated the -195 (C-->G) mutation by a functional in vitro assay based on the luciferase reporter gene system. The results indicated that the increased promoter activity observed in vivo could not be reproduced in vitro under the conditions employed, suggesting that other factors may be involved in the overexpression of the gamma-globin gene containing the -195 (C-->G) mutation. Furthermore, this is the first time that the -195 (C-->G) mutation of the Agamma-globin gene has been evaluated by in vitro gene expression.

Adult↗

14-3-3 interacts with regulator of G protein signaling proteins and modulates their activity.

Regulator of G protein signaling (RGS) proteins function as GTPase-activating proteins (GAPs) that stimulate the inactivation of heterotrimeric G proteins. We have recently shown that RGS proteins may be regulated on a post-translational level (Benzing, T., Brandes, R., Sellin, L., Schermer, B., Lecker, S., Walz, G., and Kim, E. (1999) Nat. Med. 5, 913-918). However, mechanisms controlling the GAP activity of RGS proteins are poorly understood. Here we show that 14-3-3 proteins associate with RGS7 and RGS3. Binding of 14-3-3 is mediated by a conserved phosphoserine located in the Galpha-interacting portion of the RGS domain; interaction with 14-3-3 inhibits the GAP activity of RGS7, depends upon phosphorylation of a conserved residue within the RGS domain, and results in inhibition of GAP function. Collectively, these data indicate that phosphorylation-dependent binding of 14-3-3 may act as molecular switch that controls the GAP activity keeping a substantial fraction of RGS proteins in a dormant state.

14-3-3 Proteins↗

Aquaporin 3 cloned from Xenopus laevis is regulated by the cystic fibrosis transmembrane conductance regulator.

The cystic fibrosis transmembrane conductance regulator (CFTR) is essential for epithelial electrolyte transport and has been shown to be a regulator of epithelial Na(+), K(+), and Cl(-) channels. CFTR also enhances osmotic water permeability when activated by cAMP. This was detected initially in Xenopus oocytes and is also present in human airway epithelial cells, however, the mechanisms remain obscure. Here, we show that CFTR activates aquaporin 3 expressed endogenously and exogenously in oocytes of Xenopus laevis. The interaction requires stimulation of wild type CFTR by cAMP and an intact first nucleotide binding domain as demonstrated for other CFTR-protein interactions.

Amino Acid Sequence↗

LY354740 affects startle responding but not sensorimotor gating or discriminative effects of phencyclidine.

LY354740 ¿(1S,2S,5R,6S)-2-aminobicyclo[3.1.0]hexane-2, 6-dicarboxylate monohydrate¿, a selective group II metabotropic glutamate (mGlu) receptor agonist, was recently reported to attenuate the behavioral effects of phencyclidine (PCP) in rats. In the present study, LY354740 failed to attenuate the discriminative stimulus properties of PCP and its disruption of prepulse inhibition of the acoustic startle response, at a dose range which decreased startle responding. The suggestion that mGlu group II receptor activation induces antipsychotic effects may be premature.

Acoustic Stimulation↗

Cow's-milk-induced allergic colitis in an exclusively breast-fed infant: diagnosed with ultrasound.

BACKGROUND: An exclusively breast-fed-8-week-old boy presented with irritability and non-bilious projectile vomiting. He was referred to our Medical Imaging Department to eliminate pyloric stenosis. PATIENT AND METHODS: A diagnosis of colitis was strongly suggested by ultrasound. A more detailed history revealed that the patient also had episodes of colicky pain and bloody stools. An infectious colitis was subsequently excluded and rectal biopsy supported the diagnosis of allergic proctocolitis. RESULTS: The infant responded well to the withdrawal of cow's milk and dairy products from the maternal diet. CONCLUSION: Allergic proctocolitis should be included in the differential diagnosis of infants presenting with vomiting and/or bloody stools.

Animals↗

Control of epithelial Na+ conductance by the cystic fibrosis transmembrane conductance regulator.

Cystic fibrosis transmembrane conductance regulator (CFTR) is an epithelial Cl- channel expressed in luminal membranes of secretory and reabsorptive epithelia. CFTR plays a predominant role in both cAMP- and Ca2+-activated secretion of electrolytes. Although Ca2+-dependent Cl- channels exist independent of CFTR in the airway epithelium, their physiological significance remains to be determined. However, CFTR seems to be the only relevant Cl- conductance in the colonic epithelium. Apart from its secretory function, CFTR also has a task in regulating the reabsorption of electrolytes by controlling the activity of the epithelial Na+ channel, ENaC. Accordingly, defects in CFTR causing the disease cystic fibrosis (CF) lead to disturbances of both the secretion and absorption of electrolytes. Therefore, it is unclear what is pathophysiologically more important for the development of CF lung disease, the impaired secretion of Cl- or the enhanced reabsorption of Na+ and consecutive hyperabsorption of electrolytes. The mechanisms of how CFTR and ENaC interact are unknown. Previous work has given rise to several interesting working hypothesis, such as direct protein interaction or interaction via cytoskeletal proteins. Recent studies demonstrate the importance of the first nucleotide binding fold of CFTR, not only for the inhibition of ENaC but also for the interaction with other ion channels. Further studies are required to demonstrate whether regulation of other ion channels and membrane transport by CFTR occur by a common mechanism.

Animals↗

Inwardly rectifying K+ channels in the basolateral membrane of rat pancreatic acini.

Previous studies of the whole-cell K+ conductance suggest the presence of inwardly rectifying K+ channels (Kir) in rat pancreatic acini (RPAs). Here we investigate the properties of Kir of RPAs using patch-clamp techniques. The whole-cell current-to-voltage relationship of freshly isolated RPAs was steeper for inward currents than for outward currents when the extracellular K+ concentration ([K+]o) was raised. With a high [K+]o (145 mM), external application of Ba2+ and Cs+ blocked the inward K+ current in a voltage-dependent manner. The apparent IC50 of Ba2+ was 8.5+/-1.9 microM and 1.1+/-0.2 microM at -70 mV and -130 mV, respectively (n=5). The IC50 of Cs+ was 3.5+1.1 mM and 0.2+0.1 mM at -60 mV and -120 mV, respectively (n=4). Application of Ba2+ (0.1 mM) to the extracellular solution reversibly depolarized RPAs from -43+1.1 mV to -37+/-1.2 mV (n=20). In the cell-attached configuration with 145 mM KC1 in the pipette solution, we observed inwardly rectifying channels with a high open probability (PO) of 0.85+/-0.02 (n=6) and a slope conductance (Gs) of 30+/-2.8 pS (n=13). The same type of channel was observed in the outside-out patch. We could also observe a very small conductance K+ channel which was resistant to 0.1 mM Ba2+ and did not show inward rectification (n=11). RT-PCR analysis of RPA confirmed the presence of transcripts for Kir2.1, Kir2.3 and Kir7.1 subfamilies as molecular candidates for the observed channels. The above results demonstrate the presence of Kir channels in the basolateral membrane of the RPA, which may be important for the K+ recycling process during electrolyte secretion as well as for maintaining a hyperpolarized membrane.

Animals↗

KCNE1 reverses the response of the human K+ channel KCNQ1 to cytosolic pH changes and alters its pharmacology and sensitivity to temperature.

Previous studies have shown that heteromultimeric KCNQ1/KCNE1 (KvLQT1/minK) channels and homomultimeric KCNQ1 (KvLQT1) channels exhibit different current properties, e.g. distinct kinetics and different sensitivities to drugs. In this study we report on the divergent responses to internal pH changes and further characterize some of the current properties of the human isoforms of KCNQ1 and KCNE1 expressed in Chinese hamster ovary (CHO) cells or Xenopus laevis oocytes. Decreasing the bath temperature from 37 degrees C to 20 degrees C increased the half-activation time by a factor of 5 for KCNQ1/KCNE1 currents (IKs) but by only twofold (not significant) for KCNQ1 currents (IK) in CHO cells. Acidification of cytosolic pH (pHi) increased IKs but decreased 1K whereas intracellular alkalinization decreased I(Ks) but increased IK. pHi-induced changes in intracellular Ca2+ activity ([Ca2+]i) did not correlate with the current responses. At 20 degrees C mefenamic acid (0.1 mM) significantly augmented IKs but slightly decreased IK. It changed the slow activation kinetics of I(Ks) to an instantaneous onset. The form of the current/voltage (I/V) curve changed from sigmoidal to almost linear. In contrast, at 37 degrees C, mefenamic acid also increased I(Ks) but slowed the activation kinetics and shifted the voltage activation to more hyperpolarized values without markedly affecting the sigmoidal shape of the I/V curve. The potassium channel blockers clotrimazole and tetrapentylammonium (TPeA) inhibited I(Ks) with a lower potency than I(K). These results show that coexpression of KCNE1 reversed pH regulation of KCNQ1 from inhibition to activation by acidic pHi. In addition, KCNE1 altered the pharmacological properties and sensitivity to temperature of KCNQ1. The pH-dependence of I(Ks) might be of clinical and pathophysiological relevance in the pathogenesis of ischaemic cardiac arrhythmias.

Animals↗

Effects of serotonin 5-HT(1) and 5-HT(2) receptor agonists in a conditioned taste aversion paradigm in the rat.

Although 5-HT(1/2) receptor agonists can inhibit ingestive behavior, it remains unclear whether this effect is confounded by drug-induced "malaise." The present study assessed the potential of such compounds to induce conditioned taste aversion (CTA), a possible correlate of aversive stimulus properties. Male Wistar rats were tested in a two-bottle saccharin versus water choice paradigm. DOI [5-HT(2A/2C) receptor agonist; ED(50) (95% confidence limits) in mg/kg, IP: 0.29 (0.14-0.63)], m-CPP [5-HT(2C/1B); 1.69 (0.96-2.99)], TFMPP [5-HT(1B/2C); 2.45 (1.46-4.11)], ORG 37684 [5-HT(2C); 2.96 (1. 17-7.52)], BW 723C86 [5-HT(2B); 3.49 (1.29-9.47)], CP-94,253 [5-HT(1B); 3.74 (1.54-9.08)], and ipsapirone [5-HT(1A); 20.15 (11. 25-36.09)] dose dependently suppressed saccharin preference, with potencies that correlated with their previously reported potencies to inhibit ingestive behavior in operant- and free feeding paradigms. Although these results did not necessarily imply that such hypophagic effects result from a drug-induced "malaise," it can be hypothesized that they involve, at least partly, the same physiological mechanism/substrate underlying CTA. As the hypophagic effects of serotonergic compounds have been ascribed to their effects on satiety processes and generally occur at doses that are lower than those inducing CTA, it is speculated that weak activation of this substrate results in satiety, whereas strong activation will result in aversive effects, or drug-induced "malaise."

Animals↗

Effects of serotonin(1/2) receptor agonists on dark-phase food and water intake in rats.

The effects of serotonin (5-hydroxytryptamine, 5-HT)(1/2) receptor agonists for 5-HT(1) and 5-HT(2) receptors on dark-phase ingestive behavior were evaluated in 12-h food-deprived, female Wistar rats. The amount of food and water consumed after 1, 2, 6 and 12 h was measured. The following agonists were tested: ipsapirone [preferred 5-HT receptor(s) and dose range in mg/kg, IP: 5-HT(1A) and 3-30, respectively], CP-94,253 (5-HT(1B); 0.3-3), TFMPP (5-HT(1B/2C); 0. 3-10), m-CPP (5-HT(2C/1B); 0.3-10), ORG 37684 (5-HT(2C); 0.3-10), BW 723C86 (5-HT(2B); 3-30) and DOI (5-HT(2A/2C); 0.3-3). Ipsapirone induced hyperphagia during the first hour of food access and hypophagia during the last interval. All other compounds induced dose- and time-dependent hypophagia. m-CPP and TFMPP induced the most marked reduction of food intake and were the only drugs inducing rebound hyperphagia. Except for m-CPP and TFMPP, effects on food intake could generally be dissociated from effects on water intake. The receptor profile of the compounds tested suggests that stimulation of 5-HT(1B), 5-HT(2C), 5-HT(2A) or 5-HT(2B) receptors results in hypophagia. As the less selective agonists were the more potent anorexics, it is suggested that simultaneous activation of these receptors results in synergistic effects on ingestive behavior. Additional antagonism studies are required to ascertain the proposed role of particular 5-HT receptor subtypes in the hypophagic effects of the tested compounds.

Amphetamines↗

Effects of selected serotonin 5-HT(1) and 5-HT(2) receptor agonists on feeding behavior: possible mechanisms of action.

Serotonin (5-HT) receptor agonists with high affinity for the different subtypes (i.e. 5-HT(1A-1F), 5-HT(2A-2C)) of the 5-HT(1)- and 5-HT(2) receptor families have been shown to affect ingestive behavior. It has been assumed that: (1) stimulation of hypothalamic 5-HT(2C) or 5-HT(1B) receptors leads to a behaviorally specific hypophagic effect by accelerating satiety processes; (2) stimulation of 5-HT(2A) receptors leads to a disruption of the feeding cascade; and (3) stimulation of 5-HT(1A) and 5-HT(2B) receptors leads to a hyperphagic effect. The present paper reviews studies performed with the relatively selective receptor agonists ipsapirone (5-HT(1A)), CP-94,253 (5-HT(1B)), BW 723C86 (5-HT(2B)) and ORG 37684 (5-HT(2C)), as well as the nonselective receptor agonists TFMPP (5-HT(1B/2C)), m-CPP (5-HT(2C/1B)) and DOI (5-HT(2A/2C)) in a variety of feeding paradigms in rats, both after systemic and local injection. These studies support a role for other neuroanatomical regions (i.e. brain stem) and behavioral mechanisms (i.e. appetitive processes) in the hypophagic effects of these compounds, possibly as a function of the administered dose. Studies with 5-HT receptor antagonists indicate that the proposed role of particular 5-HT(1/2) receptor subtypes in the hypophagic effects of these 5-HT receptor agonists may be more complicated than originally thought. Further characterization of the role of 5-HT(1/2) receptor subtypes in the control of ingestive behavior will require extensive pharmacological and behavioral studies, using more selective receptor agonists and antagonists and different behavioral procedures, as well as verification in transgenic animals.

Animals↗

Palatable fluids do not affect alcohol intake and its reduction by serotonergic compounds in alcohol-preferring cAA rats.

1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane (DOI) decreases alcohol intake by alcohol-preferring cAA rats more selectively than fluoxetine in a two-bottle alcohol vs. water paradigm. We report now that availability of sucrose or saccharin in a 3rd bottle does not affect (1) alcohol intake, supporting further the validity of this model of alcoholism, nor (2) the selectivity profile of the alcohol intake-reducing effects of these compounds. It is hypothesized that reduction of alcohol intake by DOI is not simply due to decreased intake of palatable fluids.

Alcohol Drinking↗

Immunohistochemical evidence for the myeloperoxidase/H2O2/halide system in human atherosclerotic lesions: colocalization of myeloperoxidase and hypochlorite-modified proteins.

The 'oxidation theory' of atherosclerosis proposes that oxidation of low density lipoprotein (LDL) contributes to atherogenesis. Although the precise mechanisms of in vivo oxidation are widely unknown, increasing evidence suggests that myeloperoxidase (MPO, EC 1.11.1.7), a protein secreted by activated phagocytes, generates modified/oxidized (lipo)proteins via intermediate formation of hypochlorous acid (HOCl). In vitro generation of HOCl transforms lipoproteins into high uptake forms for macrophages giving rise to cholesterol-engorged foam cells. To identify HOCl-modified-epitopes in human plaque tissues we have raised monoclonal antibodies (directed against human HOCl-modified LDL) that do not cross-react with other LDL modifications, i.e. peroxynitrite-LDL, hemin-LDL, Cu2+-oxidized LDL, 4-hydroxynonenal-LDL, malondialdehyde-LDL, glycated-LDL, and acetylated-LDL. The antibodies recognized a specific epitope present on various proteins after treatment with OCl- added as reagent or generated by the MPO/H2O2/halide system. Immunohistochemical studies revealed pronounced staining for HOCl-modified-epitopes in fibroatheroma (type V) and complicated (type VI) lesions, while no staining was observed in aortae of lesion-prone location (type I). HOCl-oxidation-specific epitopes are detected in cells in the majority of atherosclerotic plaques but not in control segments. Staining was shown to be inside and outside monocytes/macrophages, endothelial cells, as well as in the extracellular matrix. A similar staining pattern using immunohistochemistry could be obtained for MPO. The colocalization of immunoreactive MPO and HOCl-modified-epitopes in serial sections of human atheroma (type IV), fibroatheroma (type V) and complicated (type VI) lesions provides further convincing evidence for MPO/H2O2/halide system-mediated oxidation of (lipo)proteins under in vivo conditions. We propose that MPO could act as an important link between the development of atherosclerotic plaque in the artery wall and chronic inflammatory events.

Aged↗

Factors affecting morbidity, mortality, and survival in patients undergoing Ivor Lewis esophagogastrectomy.

OBJECTIVES: To examine the safety of transthoracic esophagogastrectomy (TTE) in a multidisciplinary cancer center and to determine which clinical parameters influenced survival and the rates of death and complications. SUMMARY BACKGROUND DATA: Although the incidence of cancer at the gastroesophageal junction has been rising rapidly in the United States, controversy still exists about the safety of surgical procedures designed to remove the distal esophagus and proximal stomach. Alternatives to TTE have been proposed because of the reportedly high rates of death and complications associated with the procedure. METHODS: Data from 143 patients treated by TTE by one author (1989-1999) were entered into a computerized database. Preoperative clinical parameters were tested for effect on death, complications, and survival. RESULTS: The patient population consisted of 127 men and 16 women. One hundred twenty-one patients had a history of tobacco abuse, and 118 reported the regular ingestion of alcohol. One hundred fifteen patients had adenocarcinoma, 16 had squamous cell cancer, 6 had another form of esophageal tumor, and 6 had high-grade dysplasia associated with Barrett epithelia. Fifty-six patients had adenocarcinomas arising in Barrett epithelium. Twenty-eight patients were treated with neoadjuvant chemoradiation before surgery. Three patients died within 30 days of surgery (mortality rate 2.1%). Five patients (3.5%) had a documented anastomotic leak; three died). Overall, 42 patients had complications (29%). Twenty-six had pulmonary complications (19%). The mean length of stay in the intensive care unit was 3.35 days; the mean hospital length of stay was 13.54 days. The overall 3-year survival rate was 29.6%. CONCLUSIONS: A high ASA score and the development of complications predicted an increased length of stay. The presence of diabetes predicted the development of complication and an increased length of stay. None of the other parameters tested predicted perioperative death or complications. Only disease stage, diabetes, and blood transfusion affected overall survival. From these results with a large series of patients with gastroesophageal junction cancers, TTE can be performed with a low death rate (2.1%), a low leak rate (3. 5%), and an acceptable complication rate (29%).

Adenocarcinoma↗

Menadione-induced oxidative stress inhibits cholecystokinin-stimulated secretion of pancreatic acini by cell dehydration.

The present study evaluated the effects of free radicals generated by menadione on morphology and function of pancreatic acinar cells focusing on enzyme secretion, stimulus-secretion coupling, and cell hydration. Various experiments evaluated morphology and function of isolated rat pancreatic acinar cells exposed to menadione. Menadione instantaneously generated free radicals (luminol and deoxyribose assays) followed by a time-dependent cell injury (uptake of trypan blue). Early ultrastructural changes included vacuolization and alterations of mitochondria, endoplasmic reticulum, and nucleus. Menadione caused a rapid glutathione oxidation followed by a depletion in reduced glutathione. An increase in lipid peroxides and a depletion of adenosine triphosphate were seen only after 30-60 minutes. Menadione markedly inhibited amylase release stimulated by cholecystokinin (CCK) and carbachol and simultaneously caused cell shrinkage after a few minutes. Similar degrees of cell shrinkage induced by hyperosmolar incubation and by menadione inhibited amylase secretion to a similar extent. CCK binding and its effect on calcium and inositol 1,4,5-trisphosphate (IP3) were not affected by menadione. Menadione (without CCK) induced an instantaneous increase of intracellular calcium followed by a slow constant increase. In single cells, menadione induced calcium oscillations with a frequency lower than that seen after CCK stimulation. Some morphologic and functional alterations owing to menadione-induced oxidative stress may be caused by adenosine triphosphate and glutathione depletion, lipid peroxidation, and changes in cytosolic calcium. The marked inhibition of secretagogue-stimulated enzyme secretion owing to menadione may be mediated to a large part by cell dehydration, whereas classical steps of stimulus-secretion coupling like receptor binding, calcium release, and IP3 generation remained unchanged.

Adenosine Triphosphate↗

Being strong: how black West-Indian Canadian women manage depression and its stigma.

PURPOSE: To discover how women from a nondominant cultural background (West Indian) experience and manage depression. DESIGN: Explanatory using grounded theory. METHODS: Semistructured interviews were conducted with 12 Black West-Indian Canadian women who experienced depression. Between 1994 and 1996, the first author engaged in participant observation. FINDINGS: The women used the basic social process they called "being strong" to manage or ameliorate depression. Being strong included "dwelling on it," "diverting myself," and "regaining my composure." For most of the women, the range of available life choices was limited to the three processes; however, a few engaged in "trying new approaches." These women were less limited in their range of cultural and behavioral boundaries than were the others, and began tentatively to explore other options for themselves. CONCLUSIONS: Black West-Indian Canadian women in this study managed their depression in culturally defined ways by being strong and not showing vulnerability. Because being strong was also evident in a previous study of dominant-culture women as a prelude to depression, the process may be widespread in women prone to depression. The findings provide helpful information for intervening in an unfamiliar culture.

Black or African American↗

Amino acid transport in podocytes.

It has recently been shown that formation of podocyte foot processes is dependent on a constant source of lipids and proteins (Simons M, Saffrich R, Reiser J, and Mundel P. J Am Soc Nephrol 10: 1633-1639, 1999). Here we characterize amino acid transport mechanisms in differentiated cultured podocytes and investigate whether it may be disturbed during podocyte injury. RT-PCR studies detected mRNA for transporters of neutral amino acids (ASCT1, ASCT2, and B(0/+)), cationic AA (CAT1 and CAT3), and anionic AA (EAAT2 and EAAT3). Alanine (Ala), asparagine, cysteine (Cys), glutamine (Gln), glycine (Gly), leucine (Leu), methionine (Met), phenylalanine (Phe), proline (Pro), serine (Ser), threonine (Thr), glutamic acid (Glu), arginine (Arg), and histidine (His) depolarized podocytes and increased their whole cell conductances. Depletion of extracellular Na(+) completely inhibited the depolarization induced by Ala, Gln, Glu, Gly, Leu, and Pro and decreased the depolarization induced by Arg and His, indicating the presence of Na(+)-dependent amino acid transport. Incubation of podocytes with 100 microg/ml puromycin aminonucleoside for 24 h significantly attenuated the effects induced by the various amino acids by approximately 70%. The data indicate the existence of different amino acid transporter systems in podocytes. Alteration of amino acid transport may participate in podocyte injury and disturbed foot process formation.

Amino Acids↗

A Bartter's syndrome mutation of ROMK1 exerts dominant negative effects on K(+) conductance.

Mutations in the gene encoding the renal epithelial K(+) channel ROMK1 (Kir 1.1) is one of the causes for Bartter's syndrome, an autosomal recessive disease. It results in defective renal tubular transport in the thick ascending limb of the loop of Henle that leads to hypokalemic metabolic alkalosis and loss of salt. Two novel ROMK1 mutations, L220F/A156V, have been described recently in a compound heterozygote patient demonstrating typical manifestations of Bartter's syndrome. Functional properties of these ROMK1 mutants were studied by coexpressing in Xenopus oocytes and by means of double electrode voltage clamp experiments. When both ROMK1 mutants were coexpressed no K(+) conductance could be detected. The same was found in oocytes expressing A156V-ROMK1 only or coexpressing wild type (wt) ROMK1 together with A156V-ROMK1. In contrast, K(+) conductances were indistinguishable from that of wt-ROMK1 when L220F-ROMK1 was expressed alone. Activation of protein kinase C signaling inhibited the conductance in both L220F-ROMK1 and wt-ROMK1 expressing oocytes. These effects were not seen in A156V-ROMK1 expressing oocytes. Because no further abnormalities in the properties or regulation of L220F-ROMK1 were detected, we conclude that A156V-ROMK1 has a dominant negative effect on L220F-ROMK1 thereby causing Bartter's syndrome type two in this patient.

Bartter Syndrome↗