Gastrin-releasing peptide-, calcitonin gene-related peptide-, and calcitonin-like immunoreactivity in human breast cyst fluid and gastrin-releasing peptide-like immunoreactivity in human breast carcinoma cell lines

To assess the role of growth factors in proliferative disorders of the breast, we assayed breast cyst fluid from 70 patients for calcitonin-related peptides. Cyst fluids (5.4 +/- 6.6 ml) (mean +/- SD) (n = 70) contained 10,499 +/- 8272 pg/ml of gastrin-releasing peptide (GRP)-like immunoreactivity in 66 of 70 samples. Calcitonin gene-related peptide (CGRP)-like immunoreactivity was found in 64 of 64 samples tested (3842 +/- 2048 pg/ml). Calcitonin-like immunoreactivity was detected in 47 of 69 samples (185 +/- 106 pg/ml). Significant correlations were found for GRP versus volume, CGRP, and calcitonin, for calcitonin versus volume and CGRP, and for CGRP versus volume. Extracts of two human breast carcinoma cell lines (MCF-7 and BT-20) contained measurable GRP-like immunoreactivity. We conclude that GRP-, CGRP-, and calcitonin-like immunoreactivities are present in human breast cyst fluid and that GRP-like immunoreactivity is present in two established human breast carcinoma cell lines. High concentrations of GRP-like immunoreactivity in both breast cyst fluid and breast carcinoma tissue, taken together with the known mitogenic and trophic activities of this peptide, support the hypothesis that GRP may be an important factor in human breast disease.     

Akt Substrate of 160 kD Regulates Na+,K+-ATPase Trafficking in Response to Energy Depletion and Renal Ischemia

Renal ischemia and reperfusion injury causes loss of renal epithelial cell polarity and perturbations in tubular solute and fluid transport. Na⁺,K⁺-ATPase, which is normally found at the basolateral plasma membrane of renal epithelial cells, is internalized and accumulates in intracellular compartments after renal ischemic injury. We previously reported that the subcellular distribution of Na⁺,K⁺-ATPase is modulated by direct binding to Akt substrate of 160 kD (AS160), a Rab GTPase-activating protein that regulates the trafficking of glucose transporter 4 in response to insulin and muscle contraction. Here, we investigated the effect of AS160 on Na⁺,K⁺-ATPase trafficking in response to energy depletion. We found that AS160 is required for the intracellular accumulation of Na⁺,K⁺-ATPase that occurs in response to energy depletion in cultured epithelial cells. Energy depletion led to dephosphorylation of AS160 at S588, which was required for the energy depletion–induced accumulation of Na,K-ATPase in intracellular compartments. In AS160-knockout mice, the effects of renal ischemia on the distribution of Na⁺,K⁺-ATPase were substantially reduced in the epithelial cells of distal segments of the renal tubules. These data demonstrate that AS160 has a direct role in linking the trafficking of Na⁺,K⁺-ATPase to the energy state of renal epithelial cells.     

Mechanisms of PKC-Dependent Na+ K+ ATPase Phosphorylation in the Rat Kidney with Chronic Renal Failure

The present work was designed to study Na⁺ K⁺ ATPase α1-subunit phosphorylation in rats with chronic renal failure (CRF) in comparison with normal rats. Na⁺ K⁺ ATPase α1-subunit phosphorylation degree was measured by binding the McK-1 antibody to dephosphorylated Ser-23 in microdissected medullary thick ascending limb of Henle (mTAL) segments. In addition, the total Na⁺ K⁺ ATPase α1-subunit expression and activity were also measured in the outer renal medulla homogenates and membranes.

CRF rats showed a higher Na⁺ K⁺ ATPase activity, as compared with control rats (18.95 ± 2.4 vs. 11.21 ± 1.5 μmol Pi/mg prot/h, p < 0.05), accompanied by a higher total Na⁺ K⁺ ATPase expression (0.54 ± 0.04 vs. 0.27 ± 0.02 normalized arbitrary units (NU), p < 0.05). When McK-1 antibody was used, a higher immunosignal in mTAL of CRF rats was observed, as compared with controls (6.3 ± 0.35 vs.4.1 ± 0.33 NU, p < 0.05). The ratio Na⁺ K⁺ ATPase α1-subunit phosphorylation / total Na⁺ K⁺ ATPase α1-subunit expression per μg protein showed a non-significant difference between CRF and control rats in microdissected mTAL segments (2.11 ± 0.12 vs.2.26 ± 0.18 NU, p = NS). The PKC inhibitor RO-318220 10^?6M increased immunosignal (lower phosphorylation degree) in mTAL of CRF rats to 128.43 ± 7.08% (p < 0.05) but did not alter McK1 binding in control rats. Both phorbol 12-myristate 13-acetate (PMA) 10^?6M and dopamine 10^?6M decreased immunosignal in CRF rats, corresponding to a higher Na⁺ K⁺ ATPase α1-subunit phosphorylation degree at Ser-23 (55.26 ± 11.17% and 53.27 ± 7.12% compared with basal, p < 0.05). In mTAL of CRF rats, the calcineurin inhibitor FK-506 10^?6M did not modify phosphorylation degree at Ser-23 of Na⁺ K⁺ ATPase α1-subunit (100.21 ± 3.00% compared with basal CRF). In control rats, FK 506 10^?6M decreased the immunosignal, which corresponds to a higher Na⁺ K⁺ ATPase α1-subunit phosphorylation degree at Ser-23. The data suggest that the regulation of basal Na⁺ K⁺ ATPase α1-subunit phosphorylation degree at Ser-23 in mTAL segments of CRF rats was primarily dependent on PKC activation rather than calcineurin dependent mechanisms.     

Caveolin-1 Deficiency Inhibits the Basolateral K+ Channels in the Distal Convoluted Tubule and Impairs Renal K+ and Mg2+ Transport

Kcnj10 encodes the inwardly rectifying K⁺ channel Kir4.1 in the basolateral membrane of the distal convoluted tubule (DCT) and is activated by c-Src. However, the regulation and function of this K⁺ channel are incompletely characterized. Here, patch-clamp experiments in Kcnj10-transfected HEK293 cells demonstrated that c-Src–induced stimulation of Kcnj10 requires coexpression of caveolin-1 (cav-1), and immunostaining showed expression of cav-1 in the basolateral membrane of parvalbumin-positive DCT. Patch-clamp experiments detected a 40-pS inwardly rectifying K⁺ channel, a heterotetramer of Kir4.1/Kir5.1, in the basolateral membrane of the early DCT (DCT1) in both wild-type (WT) and cav-1-knockout (KO) mice. However, the activity of this basolateral 40-pS K⁺ channel was lower in KO mice than in WT mice. Moreover, the K⁺ reversal potential (an indication of membrane potential) was less negative in the DCT1 of KO mice than in the DCT1 of WT mice. Western blot analysis demonstrated that cav-1 deficiency decreased the expression of the Na⁺/Cl^– cotransporter and Ste20-proline-alanine-rich kinase (SPAK) but increased the expression of epithelial Na⁺ channel-α. Furthermore, the urinary excretion of Mg²⁺ and K⁺ was significantly higher in KO mice than in WT mice, and KO mice developed hypomagnesemia, hypocalcemia, and hypokalemia. We conclude that disruption of cav-1 decreases basolateral K⁺ channel activity and depolarizes the cell membrane potential in the DCT1 at least in part by suppressing the stimulatory effect of c-Src on Kcnj10. Furthermore, the decrease in Kcnj10 and Na⁺/Cl^– cotransporter expression induced by cav-1 deficiency may underlie the compromised renal transport of Mg²⁺, Ca²⁺, and K⁺.     

Effect of free radical scavengers on myocardial function and Na+, K+-ATPase activity in stunned rabbit myocardium

Objectives. The role of reactive oxygen species (ROS) in the mechanism of myocardial stunning was investigated. Material and methods. Isolated Langendorff-perfused rabbit hearts were subjected to 15?min normothermic ischemia followed by 10?min reperfusion with Krebs-Henseleit solution±mannitol or histidine. Results. In hearts reperfused without free radical scavenger the left ventricular developed pressure as well as its maximal positive and negative first derivatives (+dP/dt, ?dP/dt) was significantly depressed, whereas end diastolic pressure (LVEDP) increased when compared to preischemic values. Treatment with mannitol had little protective effects, whereas singlet oxygen scavenger histidine significantly improved the recovery of LVEDP and ?dP/dt. Sarcolemmal Na⁺, K⁺-ATPase activity (control, 400±41 nmol P_i.min^?1.mg^?1) was depressed in untreated stunned hearts (260±27 nmol P_i.min^?1.mg^?1), but was almost completely recovered in hearts pretreated with histidine (364±27 nmol P_i.min^?1.mg^?1). The inhibition of Na⁺, K⁺-ATPase was only slightly prevented by mannitol (302±29 nmol P_i.min^?1.mg^?1l). Conclusions. The results suggest that ROS-induced inhibition of Na⁺, K⁺-ATPase activity is involved in the mechanism of postischemic contractile dysfunction and support the view that singlet oxygen may be one of the major causes of oxidative injury during ischemia and reperfusion.     

Breast cyst type does not predict the natural history of cyst disease or breast cancer risk

The sodium (Na) and potassium (K) concentrations were measured in the fluid of 169 breast cysts aspirated from 101 consecutive patients presenting to a single clinic. The Na/K ratio was used to define cysts as either apocrine (Na/K less than 3) or flattened (Na/K less than 3) in type. There was no consistency in the type of cyst for individual patients. Cyst type was not predictive of further cyst development, neither was a particular cyst type associated with the development of, or a history of, breast cancer.     

Neurokinin A is the predominant tachykinin in human bronchoalveolar lavage fluid in normal and asthmatic subjects

BACKGROUND—Multiple sensoryneuropeptides are present in human airways and may contributeto diseases such as asthma. This study quantified and characterisedsubstance P (SP), neurokinin A (NKA), and calcitonin gene relatedpeptide (CGRP) immunoreactivity in bronchoalveolar lavage fluid inasthmatic and normal subjects.
METHODS—Using specific radioimmunoassay(RIA), SP, NKA and CGRP were measured in bronchoalveolar lavage fluidfrom asthmatic subjects (n = 5), normal subjects (n = 5), atopicnon-asthmatic subjects (n = 6), and asthmatic subjects four hours afterallergen challenge (n = 12). Peptide immunoreactivity was characterisedusing high performance liquid chromatography (HPLC) and RIA.
RESULTS—No SP or CGRP immunoreactivity wasdetected in any of the fractions from samples after extraction, HPLC,and RIA. Non-specific binding resulted in spurious SP immunoreactivitybeing detected in bronchoalveolar lavage fluid when no extractionprocess was employed. NKA was detected in significant amounts inasthmatic (median 550, range 425-625 pg/ml) and normal subjects(median 725, range 350-1425 pg/ml). The level of NKA wassignificantly higher in the asthmatic subjects after allergen challenge(median 750, range 350-1250 pg/ml) than in unchallenged asthmaticsubjects (median 600, range 425-600 pg/ml, p<0.01).
CONCLUSIONS—Extraction and characterisationof peptides from bronchoalveolar lavage fluid must be performed toensure that the measured immunoreactivity represents target peptide.NKA is present in bronchoalveolar lavage fluid in high concentrationsand is the predominant tachykinin. The concentrations of NKA aresimilar in normal subjects and subjects with mild asthma.

     

Pancreatic cyst fluid glucose: rapid,inexpensive, and accurate diagnosis of mucinous pancreatic cysts

Background

The most widely accepted biochemical test for preoperative differentiation of mucinous from benign, nonmucinous pancreatic cysts is cyst fluid carcinoembryonic antigen. However, the diagnostic accuracy of carcinoembryonic antigen ranges from 70% to 86%. Based on previous work, we hypothesize that pancreatic cyst fluid glucose may be an attractive alternative to carcinoembryonic antigen.

Luminal osmolarity downregulates gene expression of Na+/H+ exchanger (NHE3) in rat colon mucosa

Water-coupled Na⁺ absorption in the colon is mediated principally by Na⁺/H⁺ exchange (isoforms NHE2 and NHE3). To determine whether luminal ion composition or osmolarity influences NHE expression in colon mucosa, two groups (n = 6 in each) of adult male Sprague-Dawley rats underwent sham laparotomy or loop ileostomy. In these studies, diversion did not markedly alter mRNA levels for NTHE2, NHE3, or Na⁺/K⁺, at 8 or 21 days, indicating that loss of luminal volume does not alter NHE gene expression. To evaluate the effects of specific luminal components, we infused equal volumes of half-normal (154 mOsm) or iso-osmolar (308 mOsm) solutions of saline and mannitol into the diverted colon. All solutions elicited significant (45% to 60%; P <0.05) decreases in mRNA levels for NHE3, with iso-osmolar mannitol eliciting the greatest changes. Decreases in NHE2 and Na⁺/K⁺ mRNA levels were observed following these infusions but were not as marked as the changes for NHE3. These findings suggest that (1) loss of luminal Na⁺ is not, in itself, a signal that regulates NHE expression and (2) infusion of any solute, including Na⁺ itself, provides a signal to downregulate expression of NHE3 in colon mucosa. Supported by the Brigham Surgical Group Foundation and National Institutes of Health Award RO1-DK44571 (D.I.S.).     

Interstitial fluid pressure in breast cancer,benign breast conditions,and breast parenchyma

Background: Interstitial fluid pressure (IFP) in rodent malignant tumors is reportedly much higher than in surrounding normal tissue. We hypothesized the same may be true in human invasive breast tumors. Methods: We measured IFP in the operating room in 25 patients undergoing excision breast biopsy under local anesthetic for diagnostic purposes. Results: In patients with invasive ductal carcinomas IFP was 29 ± 3 (SE) mm Hg, compared with ?0.3 ± 0.1 mm Hg in those with normal breast parenchyma (p < 0.001), 3.6 ± 0.8 mm Hg in those with benign tumors (p < 0.003), ?0.3 ± 0.2 mm Hg in those with noninvasive carcinomas (p = 0.034), and 0.4 ± 0.4 mm Hg in those with other benign breast conditions (p = 0.002). There was a direct correlation between IFP and tumor size (R ² = 0.3977; p = 0.021). No correlation was found between IFP and nuclear grade, angiolymphatic invasion, systemic blood pressure, metastasis to lymph nodes, or estrogen and progesterone receptors. Conclusions: IFP measurements may facilitate radiographic or ultrasound localization of small or nonpalpable malignant tumors in those patients undergoing needle aspiration cytology or stereotactic core needle biopsy.     

Clinical features of cyst infection and hemorrhage in ADPKD: new diagnostic criteria

Background and objectives

Cyst infection and cyst hemorrhage are frequent and serious complications of autosomal dominant polycystic kidney disease (ADPKD), often being difficult to diagnose and treat. The first objective of this study is to clarify the clinical features of ADPKD patients with cyst hemorrhage or infection. The second objective is to establish diagnostic criteria for ADPKD patients with cyst infection or cyst hemorrhage.

Patients and methods

Patients with definite cyst infection or hemorrhage were enrolled from among the ADPKD patients referred to us between January 2004 and October 2011. We investigated their symptoms, laboratory data, and the computed tomography (CT)/magnetic resonance imaging (MRI) features of infected cysts (before and after onset), normal cysts, and cysts with hemorrhage.

Results

There were 24 patients with cyst infection (36 infected cysts) and 12 patients with acute cyst hemorrhage (13 bleeding cysts). White blood cell (WBC) count >10,000/??l, serum C-reactive protein (CRP) >15.0?mg/dl, and body temperature >38?°C strongly suggested cyst infection. All of the cysts with hemorrhage contained a high-density mass-like area or showed overall high density on CT, and all patients with cyst hemorrhage had abdominal pain or gross hematuria. On the other hand, infected cysts showed an increase of intensity on MRI [diffusion-weighted imaging (DWI)], while a fluid?Cfluid level, wall thickening, and gas were also evidence of infection. Abdominal pain and/or sequential changes on MRI after onset of symptoms were useful for localizing infected cysts.

Conclusion

Acute cyst hemorrhage and infection can be identified from symptoms, laboratory data, and CT/MRI findings.     

Ca2+ ATPase in Dutch Warmblood Foals Compared with Na+, K+ ATPase: Intermuscular Differences and the Effect of Exercise

We studied the effects of exercise without or with a subsequent period on pasture on Ca²⁺ ATPase concentration in foal skeletal muscle, and compared the results with those previously reported on Na⁺, K⁺ ATPase. Ca²⁺ ATPase was measured in homogenates as Ca²⁺‐dependent steady‐state phosphorylation from [γ‐³²P]ATP. From day 7 after birth, 24 foals were divided into three groups: (i) staying in a box stall (Box); (ii) staying in a box stall with an exercise programme of an increasing number of sprints per day (Exercise); and (iii) staying on pasture (Pasture). Half of the foals (12 with four in each treatment group) were killed after 5 months. The remaining foals stayed on pasture until 11 months. In the 5‐month Pasture group, Ca²⁺ ATPase concentration was 29.4 ± 4.3 nmol/g wet weight (wt) (n = 4) in gluteus medius muscle, 25.2 ± 3.3 nmol/g wet wt (n = 4) in semitendinosus muscle (both mixed fibre type), and 4.1 ± 1.7 nmol/g wet wt (n = 3) in the slow masseter muscle. These values were not altered by exercise or by box rest. This was in contrast to the Na⁺, K⁺ ATPase concentration which was not different between the three muscles, but showed a 20% rise in gluteus medius and semitendinosus muscle after exercise. In the period from 5 to 11 months on pasture, there was no change in Ca²⁺ ATPase in any group. In conclusion, the Ca²⁺ ATPase concentration in foal muscle is around 6‐fold higher in mixed fibres than in slow fibres. Furthermore, the enzyme is not up‐ or down‐regulated by sprint exercise or subsequent rest.     

Effects of aging and potassium depletion on renal collecting tubule K+-controlling ATPases

SUMMARY: The effects of aging and potassium depletion (KD) on renal cortical and medullary collecting tubule (CCT and MCT) K⁺‐controlling ATPase activities, Na⁺,K⁺‐ATPase and H⁺,K⁺‐ATPase, were performed in 4 and 30 month‐old male Fischer 344 x Brown‐Norway F1 (F344xBNF1) rate. Following KD, which was induced by a K⁺‐deficient diet for 7 days, both animal age groups had comparable levels of hypokalaemia, but the decreased fractional excretion of K⁺ (FEK⁺) was more prominent in the old‐age group. the aged animals had a 37% lower basal Na⁺,K⁺‐ATPase activity in MCT (P < 0.05), but marked increases in basal H⁺,K⁺‐ATPase activity in both CCT and MCT (P<0.001) were noted. Potassium depletion resulted in 28% (P<0.05) and 66% (P<0.01) increases in CCT and MCT Na⁺,K⁺‐ATPase activities, respectively, in the young‐age group. In the old‐age group, KD caused a 125% (P< 0.001) increase in MCT Na⁺,K⁺‐ATPase activity, but had no effect on CCT Na⁺,K⁺‐ATPase activity. the collecting tubule H⁺,+‐ATPase activity was increased in both the young and old‐age KD groups. the increase of magnitude in the latter was much higher than in the former. In response to KD, the more prominent rises in CCT and MCT H⁺,K⁺‐ATPase activities (with an increased percentage in MCT Na⁺,K⁺‐ATPase activity) was observed in the old‐age animals when compared with the younger ones. This could result in an increased K⁺ reabsorption, leading to the lower value of FEk⁺. Thus, the K⁺‐controlling mechanisms in the renal collecting tubule of aging rats are still intact and effective in coping with KD.     

Analysis of Fluid in Cysts Accompanying Various Primary and Metastatic Brain Tumours: Proteins, Lactate and pH

Summary There is a growing interest in cystic lesions of the brain. By examining the cyst content of brain tumours more insight into the pathogenesis of cyst formation has been found. In this study, 39 samples of cyst fluid of 34 patients with a cyst accompanying a brain tumour were collected and studied biochemically regarding their protein content, lactate and pH. In this study we investigated the relation between the grade of malignancy and the lactate-concentration and the discrepancy between the high levels of lactate in cysts and their alkaline environment. The results of the measurements of the concentrations of albumin, immunoglobulins (IgG, IgA, IgM) and α₂-macroglobulin in cysts compared to those in sera suggest that cyst formation associated with tumour is based upon a disruption of the blood-brain barrier with exudation of plasma proteins into the brain parenchyma resulting in accumulation of fluid (oedema) and eventually in formation of a cyst. There appears to be a positive relation between the grade of malignancy and the concentration of lactate in the cysts with a significant 2-fold increase in lactate concentration in malignant tumour cysts compared to the more benign tumour cysts (p<0.001) probably on account of aerobic glycolysis with production of lactate by the tumour. The measured pH values in the cysts were above normal, resulting in a discrepancy of the high levels of lactate in the cyst with the alkaline environment and this suggests efflux of H⁺-ions by a Na/H exchange mechanism to compensate for the change of pH.     

Trimethoprim-sulfamethoxazole in cyst fluid from autosomal dominant polycystic kidneys

Cyst infection in patients with autosomal-dominant polycystic kidney disease (ADPKD) is often refractory to therapy, in part because of the limited entry of commonly used antibiotics into cyst fluid. To study the efficacy of trimethoprim-sulfamethoxazole in cyst infection, cyst fluid was obtained by percutaneous aspiration or at surgery from eight patients with ADPKD receiving trimethoprim-sulfamethoxazole. Cysts were categorized as nongradient or gradient by cyst-fluid sodium concentration. Trimethoprim-sulfamethoxazole concentrations within cysts were determined and cyst fluid inhibitory and bactericidal titers were assessed in vitro against Escherichia coli, Proteus mirabilis and Streptococcus fecalis. The mean cyst fluid trimethoprim and sulfamethoxazole concentrations were 15.2 micrograms/ml and 42.5 micrograms/ml, respectively. Preferential accumulation of trimethoprim was observed in gradient cysts, exceeding serum levels more than eightfold. Sulfamethoxazole penetrated cysts to a lesser extent, with concentrations ranging from 10 to 70 percent of the serum level. Cyst fluid sampled prior to trimethoprim-sulfamethoxazole administration (control) demonstrated no antibacterial activity, while cyst fluid inhibitory and bactericidal titers following antibiotic administration were 1:32 or greater in most instances. These studies indicate that trimethoprim-sulfamethoxazole is likely to be efficacious in the treatment of cyst infection in polycystic kidneys.     

Calcitonin, calcitonin gene-related peptide, and gastrin-releasing peptide in familial thyroid medullary carcinoma

We examined immunocytochemically the occurrence of the three peptides calcitonin, calcitonin gene-related peptide (CGRP), and gastrin-releasing peptide (GRP) in medullary carcinoma of the thyroid. We also sought to determine whether the plasma levels of these peptides were increased when stimulated with calcium and pentagastrin in familial medullary carcinoma of the thyroid (MCT). The tumor tissue from all 17 cases examined was found to exhibit calcitonin and CGRP immunoreactivity, and in 15 of the 17 cases the tumor tissue also contained GRP immunoreactivity. In 7 of the cases selected at random, an intravenous injection of calcium carbonate (2 mg/kg body weight) and pentagastrin (0.6 microgram/kg body weight) produced marked elevation in plasma levels of calcitonin but did not significantly alter the plasma levels of CGRP or GRP. We conclude that most MCT tumors contain CGRP and GRP immunoreactive cells but that the plasma levels of CGRP and GRP are not altered on stimulation. This finding is clearly in contrast to the markedly elevated calcitonin levels. Hence, determination of plasma calcitonin levels still seems to be the most appropriate diagnostic test for MCT.     

Subchondral cysts in dysplastic osteoarthritic hips communicate with the joint space: analysis using three-dimensional computed tomography

Introduction

Bone cyst formation in hips increases as osteoarthritis worsens. Although bone cysts in hips have been described in many studies, their etiology remains unclear and under debate. The purpose of this study was to investigate the communication between a bone cyst and the joint space, as well as the relationship between the severity of osteoarthritis and the formation of subchondral bone cysts in dysplastic hips.

Method

We studied bone cysts from 150 dysplastic hips in 97 patients by computed tomography (CT) and plain radiography. We investigated the distribution of the bone cysts and the presence or absence of a communication path between the cysts and the joint space by three-dimensional (3D) CT.

Result

Of the 150 hips, 94 acetabula and 55 femoral heads were found to contain cysts. Of the 94 hips containing acetabular cysts, 89 and 5 hips showed black lines and gray lines connecting the cyst and the joint space, respectively, on 3D-CT. The rate of cyst presentation in the hip increased as the joint space became narrower. The number of hips that possessed cysts in the anterior and/or middle portion was significantly higher than that in the posterior portions.

Conclusion

Bone cysts in dysplastic osteoarthritic hips were found to communicate with the joint space in all cases. This suggests that the formation and enlargement of the cysts in dysplastic hips may be greatly influenced by the joint fluid. Cyst formation was initially observed in the anterior acetabulum, gradually progressing to involve the entire joint, including the posterior acetabulum and the femoral head, with worsening of the osteoarthritis.     

Luminal regulation of Na+/H+ exchanger gene expression in rat ileal mucosa

It is well recognized that ileostomy patients suffer from chronic depletion of Na⁺ through the stoma effluent. In this study we evaluated the effects of ileostomy on messenger RNA levels that encode different Na⁺/H⁺ exchanger isoforms (NHE-2 and NHE-3). Loop ileostomies were created in Sprague-Dawley rats. Segments of diverted ileum were harvested for quantitation of mRNA levels encoding these isoforms and the Na⁺/K⁺ ATPase in mucosal scrapings and for immunofluorescence microscopy, specifically of the NHE-3 protein. Our studies indicate that as early as 8 days after diversion, NHE-3 gene expression is selectively attenuated in poststomal ileal mucosa. Mucosal morphology remains undisturbed, and the distribution of protein expression along the crypt/villus axis is not altered. Infusion of Na⁺ or the enterocyte nutrient, glutamine, into the lumen of the diverted segment restores or even augments mRNA levels for NHE-3, again without altering the histologic appearance or distribution of the protein along the crypt/ villus axis. These effects are specific because nonpolar osmolytes (mannitol) and related organic nutrients not specific for the enterocyte (i.e., butyrate) have no effect on mRNA levels of NHE-3. Further work is required to understand how the early changes in mRNA contribute to mucosal function and response to luminal diversion. Present at the Forty-Second Annual Meeting of The Society for Surgery of the Alimentary Tract in Atlanta, Georgia, May 20–23, 2001 (poster presentation). Supported by grant RO1 DK 44571-11 from the National Institutes of Health and by funds from the Brigham Surgical Group Foundation.     

The ontogeny of the expression of K+ channel-like gene (CHIF) in the rat kidney papilla

Recently, an IsK-like potassium (K⁺) channel corticosteroid-induced gene (CHIF) was cloned. A high-K⁺ diet enhances, while a low-K⁺ diet decreases the expression of this gene. The major expression of CHIF in the adult rat kidney is in the papilla, where it is constitutive, in contrast to its inducibility by corticosteroids and a low-salt diet in the rat colon. In order to further understand the ontogeny of K⁺ clearance, we studied the presence of CHIF in the kidney papilla in different stages of rat development. Total RNA from rat kidney papillae of 1- to 3-day pre-labor unborn offspring, 2- to 3-day-old newborns, 10-day-old, 6-week-old, and 43-week-old rats underwent northern hybridization for CHIF and the α-subunit of the Na⁺-K⁺-ATPase mRNA. Minor expression of CHIF mRNA was found in fetal and newborn rat papillae, while older rats showed an age-related increase in gene expression¹.The expression of the α-sub unit of the Na⁺-K⁺-ATPase was not age related. We conclude that CHIF is present in the rat kidney papilla and the expression is related to age. The relative deficiency of CHIF in the newborn may be one of the factors responsible for the reduced K⁺ clearance in is period. Received July 23, 1997; received in revised form December 31, 1997; accepted January 2, 1998