Value of flow cytometry for MRD-based relapse prediction in B-cell precursor ALL in a multicenter setting.

PCR of TCR/Ig gene rearrangements is considered the method of choice for minimal residual disease (MRD) quantification in BCP-ALL, but flow cytometry analysis of leukemia-associated immunophenotypes (FCM-MRD) is faster and biologically more informative. FCM-MRD performed in 18 laboratories across seven countries was used for risk stratification of 1487 patients with BCP-ALL enrolled in the NOPHO ALL2008 protocol. When no informative FCM-marker was available, risk stratification was based on real-time quantitative PCR. An informative FCM-marker was found in 96.2% and only two patients (0.14%) had non-informative FCM and non-informative PCR-markers. The overall 5-year event-free survival was 86.1% with a cumulative incidence of relapse (CIR5y) of 9.5%. FCM-MRD levels on days 15 (HzR 4.0, p < 0.0001), 29 (HzR 2.7, p < 0.0001), and 79 (HzR 3.5, p < 0.0001) associated with hazard of relapse adjusted for age, cytogenetics, and WBC. The early (day 15) response associated with CIR5y adjusted for day 29 FCM-MRD, with higher levels in adults (median 2.4 × 10-2 versus 5.2 × 10-3, p < 0.0001). Undetectable FCM- and/or PCR-MRD on day 29 identified patients with a very good outcome (CIR5y = 3.2%). For patients who did not undergo transplantation, day 79 FCM-MRD > 10-4 associated with a CIR5y = 22.1%. In conclusion, FCM-MRD performed in a multicenter setting is a clinically useful method for MRD-based treatment stratification in BCP-ALL.

Correction: Minimal residual disease quantification by flow cytometry provides reliable risk stratification in T-cell acute lymphoblastic leukemia.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

T-cell acute lymphoblastic leukemia in patients 1-45 years treated with the pediatric NOPHO ALL2008 protocol.

The NOPHO ALL2008 is a population-based study using an unmodified pediatric protocol in patients 1-45 years of age with acute lymphoblastic leukemia. Patients with T-ALL were given a traditional pediatric scheme if fast responding (minimal residual disease (MRD) < 0.1% day 29), or intensive block-based chemotherapy if slow responding (MRD > 0.1% day 29). Both treatment arms included pediatric doses of high-dose methotrexate and asparaginase. If MRD ≥ 5% on day 29 or ≥0.1% after consolidation, patients were assigned to allogeneic hematopoietic stem cell transplantation. The 5-year overall survival of the 278 T-ALL patients was 0.75 (95% CI 0.69-0.81), being 0.82 (0.74-0.88) for patients 1.0-9.9 years, 0.76 (0.66-0.86) for those 10.0-17.9 years, and 0.65 (0.55-0.75) for the older patients. The risk of death in first remission was significantly higher in adults (12%) compared with the 1-9 years group (4%). The MRD responses in the three age groups were similar, and only a nonsignificant increase in relapse risk was found in adults. In conclusion, an unmodified pediatric protocol in patients 1-45 years is effective in all age groups. The traditional pediatric treatment schedule was safe for all patients, but the intensive block therapy led to a high toxic death rate in adults.

A multicenter, double-blind, randomized, parallel group study comparing polyvinyl chloride and polyvinyl chloride-free catheter materials.

PURPOSE: In this study we compared a polyvinyl chloride catheter with a new polyvinyl chloride-free catheter with the same hydrophilic coating, and determined whether patient perception of ease and comfort of clean intermittent catheterization was independent of the catheter material. MATERIALS AND METHODS: This investigation was designed as a randomized, double-blind, parallel group, multicenter study. Eligible patients were experienced users of clean intermittent catheterization with a polyvinyl chloride catheter for a minimum of 1 month before randomization. They were randomized to continue to use the polyvinyl chloride catheter or switch to a polyvinyl chloride-free catheter for 4 weeks. Both catheters had a similar appearance. Patient perception of ease and comfort of clean intermittent catheterization was scored with questionnaires, and adverse events were documented. RESULTS: A total of 195 patients were recruited from 6 countries and 13 centers for the intent to treat analysis, and 179 were used for the per protocol analysis. Before randomization 94% to 98% of the patients rated the polyvinyl chloride catheter as easy or manageable to handle during different phases of clean intermittent catheterization and overall 92% of patients were satisfied. Of the eligible patients satisfaction was reported by 89% randomized to continue using the polyvinyl chloride catheter and by 78% randomized to switch to the polyvinyl chloride-free catheter (not significant). The rate of adverse events was low and comparable between the 2 groups. CONCLUSIONS: The study confirms that clean intermittent catheterization is easy and safe. Conversion from a polyvinyl chloride to a polyvinyl chloride-free core catheter material does not alter patient perception of catheterization.

Minimal residual disease quantification by flow cytometry provides reliable risk stratification in T-cell acute lymphoblastic leukemia.

Minimal residual disease (MRD) measured by PCR of clonal IgH/TCR rearrangements predicts relapse in T-cell acute lymphoblastic leukemia (T-ALL) and serves as risk stratification tool. Since 10% of patients have no suitable PCR-marker, we evaluated flowcytometry (FCM)-based MRD for risk stratification. We included 274 T-ALL patients treated in the NOPHO-ALL2008 protocol. MRD was measured by six-color FCM and real-time quantitative PCR. Day 29 PCR-MRD (cut-off 10-3) was used for risk stratification. At diagnosis, 93% had an FCM-marker for MRD monitoring, 84% a PCR-marker, and 99.3% (272/274) had a marker when combining the two. Adjusted for age and WBC, the hazard ratio for relapse was 3.55 (95% CI 1.4-9.0, p = 0.008) for day 29 FCM-MRD ≥ 10-3 and 5.6 (95% CI 2.0-16, p = 0.001) for PCR-MRD ≥ 10-3 compared with MRD < 10-3. Patients stratified to intermediate-risk therapy on day 29 with MRD 10-4-<10-3 had a 5-year event-free survival similar to intermediate-risk patients with MRD < 10-4 or undetectable, regardless of method for monitoring. Patients with day 15 FCM-MRD < 10-4 had a cumulative incidence of relapse of 2.3% (95% CI 0-6.8, n = 59). Thus, FCM-MRD allows early identification of patients eligible for reduced intensity therapy, but this needs further studies. In conclusion, FCM-MRD provides reliable risk prediction for T-ALL and can be used for stratification when no PCR-marker is available.

Results of NOPHO ALL2008 treatment for patients aged 1-45 years with acute lymphoblastic leukemia.

Adults with acute lymphoblastic leukemia (ALL) do worse than children. From 7/2008 to 12/2014, Nordic and Baltic centers treated 1509 consecutive patients aged 1-45 years with Philadelphia chromosome-negative ALL according to the NOPHO ALL2008 without cranial irradiation. Overall, 1022 patients were of age 1-9 years (A), 266 were 10-17 years (B) and 221 were 18-45 years (C). Sixteen patients (three adults) died during induction. All others achieved remission after induction or 1-3 intensive blocks. Subsequently, 45 patients (12 adults) died, 122 patients relapsed (32 adults) with a median time to relapse of 1.6 years and 13 (no adult) developed a second malignancy. Median follow-up time was 4.6 years. Among the three age groups, older patients more often had higher risk ALL due to T-ALL (32%/25%/9%, P<0.001), KMT2A rearrangements (6%/5%/3%, P<0.001) and higher day 29 residual leukemia for B-lineage (P<0.001), but not T-ALL (P=0.53). Event-free survival rates (pEFS5y) were 89±1% (A), 80±3% (B) and 74±4% (C) with significant differences only for non-high risk groups. Except for thrombosis, pancreatitis and osteonecrosis, the risk of 19 specified toxicities was not enhanced by age above 10 years. In conclusion, a pediatric-based protocol is tolerable and effective for young adults, despite their increased frequency of higher risk features.

Rearrangements of the tal-1 locus as clonal markers for T cell acute lymphoblastic leukemia.

Normal and aberrant immune receptor gene assembly each produce site-specific DNA rearrangements in leukemic lymphoblasts. In either case, these rearrangements provide useful clonal markers for the leukemias in question. In the t(1;14)(p34;q11) translocation associated with T cell acute lymphoblastic leukemia (T-ALL), the breakpoints on chromosome 1 interrupt the tal-1 gene. A site-specific deletion interrupts the same gene in an additional 26% of T-ALL. Thus, nearly one-third of these leukemias contain clustered rearrangements of the tal-1 locus. To test whether these rearrangements can serve as markers for residual disease, we monitored four patients with T-ALL; three of the leukemias contained a deleted (tald) and one a translocated (talt) tal-1 allele. These alleles were recognized by a sensitive amplification/hybridization assay. tald alleles were found in the blood of one patient during the 4th mo of treatment but not thereafter. Using a quantitative assay to measure the fraction of tald alleles in DNA extracts, we estimated that this month 4 sample contained 150 tald copies per 10(6) genome copies. The patient with t(1;14)(p34;q11) (talt) leukemia developed a positive assay during the 20th mo of treatment. By standard criteria, all four patients remain in complete remission 11-20 mo into treatment. We conclude that tal-1 rearrangements provide useful clonal markers for approximately 30% of T-ALLs.

Asparaginase-associated pancreatitis: a study on phenotype and genotype in the NOPHO ALL2008 protocol.

Asparaginase (ASP)-associated pancreatitis (AAP) occurs during acute lymphoblastic leukemia treatment. Among 1285 children (1.0-17.9 years) diagnosed during July 2008-December 2014 and treated according to the Nordic/Baltic ALL2008 protocol, 86 (cumulative incidence=6.8%) developed AAP. Seventy-three cases were severe (diagnostic AAP criteria persisting >72 h) and 13 mild. Cases were older than controls (median: 6.5 vs 4.5 years; P=0.001). Pseudocysts developed in 28%. Of the 20 re-exposed to ASP, 9 (45%) developed a second AAP. After a median follow-up of 2.3 years, 8% needed permanent insulin therapy, and 7% had recurrent abdominal pain. Germline DNA on 62 cases and 638 controls was genotyped on Omni2.5exome-8-v1.2 BeadChip arrays. Overall, the ULK2 variant rs281366 showed the strongest association with AAP (P=5.8 × 10-7; odds ratio (OR)=6.7). Cases with the rs281366 variant were younger (4.3 vs 8 years; P=0.015) and had lower risk of AAP-related complications (15% vs 43%; P=0.13) compared with cases without this variant. Among 45 cases and 517 controls <10 years, the strongest associations with AAP were found for RGS6 variant rs17179470 (P=9.8 × 10-9; OR=7.3). Rs281366 is located in the ULK2 gene involved in autophagy, and RGS6 regulates G-protein signaling regulating cell dynamics. More than 50% of AAP cases <10 years carried one or both risk alleles.

Prospective study of thromboembolism in 1038 children with acute lymphoblastic leukemia: a Nordic Society of Pediatric Hematology and Oncology (NOPHO) study.

UNLABELLED: ESSENTIALS: Children with acute lymphoblastic leukemia (ALL) are at risk of thromboembolism (TE). This is a prospective evaluation of the incidence, risk factors and outcomes of TE in 1038 children with ALL. TE occurred in 6.1% of children, with the highest incidence (20.5%) among those aged 15-17 years. A TE-associated case fatality of 6.4% indicates that TE is a severe complication of ALL treatment. BACKGROUND: Thromboembolism (TE) is a major toxicity in children with acute lymphoblastic leukemia (ALL) and may have a negative impact on ALL treatment. OBJECTIVES: To examine the cumulative incidence, outcomes and risk factors associated with TE in children with leukemia. PATIENTS/METHODS: We prospectively evaluated TE in 1038 Nordic children and adolescents (≥ 1 and < 18 years) diagnosed with ALL during 2008-2013 and treated according to the NOPHO (Nordic Society of Pediatric Hematology and Oncology)-ALL 2008 protocol. The cohort was followed until December 2014. Cox proportional regression was used to compute hazard ratios (HRs). RESULTS: TE events (n = 63) occurred most frequently in conjunction with asparaginase (ASP) administration (52/63). The cumulative incidence of TE was 6.1% (95% confidence interval [CI], 4.8-7.7). Being aged 15-17 years was associated with an increased risk of TE (adjusted HR of 4.0; 95% CI, 2.1-7.7). We found a TE-associated 30-day case fatality of 6.4% (95% CI, 1.8-15.5) and TE-related truncation of ASP therapy in 36.2% (21/58). Major hemorrhage occurred in 3.5% (2/58) of anticoagulated patients. Minor hemorrhage was reported in two out of 58 patients. No major bleeds occurred in children who received low-molecular-weight heparin. CONCLUSIONS: Methods to identify children and adolescents who will benefit from thromboprophylaxis during ALL treatment are called for. The truncation of ASP should be avoided. The long-term survival outcomes for ALL patients with TE require close monitoring in the future.

Inhibitory effects of meta-iodo-benzylguanidine (MIBG) on endothelial histamine receptor binding.

Meta-iodo-benzylguanidine (MIBG), a selective inhibitor of mono-ADP-ribosylation, has been shown to inhibit histamine induced inositol-trisphosphate and prostacyclin production. The purpose of this study was to evaluate the effect of MIBG on the binding of histamine to the H1-receptor and to study its effects on phospholipid metabolism in human endothelial cells. The effects of MIBG and MIBA (meta-iodo-benzylamine), which does not affect cellular ADP-ribosylation, on agonist induced cGMP production in cultured HUVEC's were measured by RIA and a binding study carried out to evaluate their effects on the binding of [3H]mepyramine to membrane fractions. MIBG (0.3 mM) reduced histamine induced cGMP production by 90.8% but did not inhibit the cGMP production induced by other agonists. MIBA had no effect. MIBG also reduced the binding of [3H]mepyramine (1.0 nM) to membrane fractions with IC50 at 0.094 mM and maximal inhibition (83%) at 0.22mM MIBG. The calculated Ki was 0.076mM. MIBG and MIBA altered phospholipid metabolism in a similar way as the cationic amphiphilic drug propranolol. MIBA caused up to 42% reduction in [3H]mepyramine binding, probably due to its inhibition of nonspecific binding. These results indicate that MIBG reduces histamine induced cGMP production by inhibiting its binding to H1-receptors and alters phospholipid metabolism in cultured endothelial cells in a similar way as known cationic amphiphilic drugs.

Epidemiology of the optic nerve grey crescent in the Reykjavik Eye Study.

AIM: To establish the epidemiology of the grey crescent in a white population within the age range most susceptible to glaucoma. METHODS: Bruce Shields was first to use this term to describe a localised, physiological pigmentation of the optic nerve neuroretinal rim tissue that is distinct from peripapillary pigmentation. An experienced glaucomatologist (KFD) evaluated stereofundus photographs of the participants of the Reykjavik Eye Study (RES)-a random sample from the national population census including people 50 years and older. 1012 right eyes could be evaluated for grey crescent. RESULTS: The prevalence of grey crescent in the right eyes was 22.0% (95% CI 10 to 25). It was more commonly found in women (27.0%: 95% CI 23 to 30) than in men (17.0%: 95% CI 14 to 21), and was most often located temporally (36.9%), 360 degrees (15.9%), or nasally (15.4%). The spherical equivalent was +1.30 dioptres (D) for those with and +0.80 D for those without grey crescent (p = 0.002), respectively. Vertical optic disc diameters were 0.203 v 0.195 units (p<0.001). There was no difference in the prevalence of grey crescent in glaucomatous or non-glaucomatous eyes (OR = 1.05, 95% CI 0.49 to 2.26). The prevalence of a grey crescent was inversely related to the prevalence of peripapillary atrophy (p = 0.001). CONCLUSIONS: The grey crescent needs to be recognised as a physiological variant in order to avoid falsely labelling eyes as having glaucomatous optic nerve damage.

Identification of potassium flux pathways and their role in the cytotoxicity of estramustine in human malignant glioma, prostatic carcinoma and pulmonary carcinoma cell lines.

Clinically-used drugs such as furosemide, bumetanide and cardiac glycosides, are modulators of transmembrane fluxes of cations. Recently, it has been suggested that the regulation of intracellular cation concentrations could be a primary target for anti-neoplastic drugs, and that the cytotoxic activity may be altered by inhibitors of cation fluxes at the level of the plasma membrane. Therefore, we investigated the mechanisms by which cations are translocated across the plasma membrane of malignant glioma (U251 MG), prostatic carcinoma (PC3) and pulmonary carcinoma (P31) cell lines. The interactions between cation flux inhibitors and the cytotoxicity of estramustine were also evaluated. Ouabain, the classical inhibitor of Na+, K+ATPase, markedly reduced 86Rb (K+) influx in all three lines, indicating that this ion transport system is present in the cells. Furosemide and especially bumetanide inhibited the 86Rb influx, indicating the presence of the Na+, K+, Cl- co-transport system. The potassium channel blocker, tetraethylammonium, but not apamin reduced the influx of 86Rb showing that high conductance K+ channels are present, but that channels of low conductance probably do not exist in these cell lines. The Na+, K+, Cl- co-transport inhibitors furosemide and bumetanide significantly reduced cytotoxicity of estramustine in P31 cells, whereas no interaction between other K+ flux inhibitors and the anti-neoplastic drugs were detected in any of the cell lines investigated. Thus, the data show that Na+, K+, ATPase and NA+, K+, Cl- co-transport systems and K+ channels of high conductance are present in malignant glioma (U251 MG), prostatic carcinoma (PC3) and pulmonary carcinoma (P31) cell lines, and that inhibition of the Na+, K+, Cl- co-transport system in P31 is associated with reduced cytotoxicity of estramustine. The results justify further studies evaluating the role of these cation flux pathways in terms of targets for anti-neoplastic therapy.

Perivascular cell protection in vivo and increased cell survival in vitro by the antihypertensive agent carvedilol following radiation.

Carvedilol, an antihypertensive drug with activity on adrenoceptors as well as on calcium channel activity, has recently been introduced. In the present study we investigated whether carvedilol interacts with the cytotoxicity induced by irradiation in vitro as well as in vivo. A daily injection of carvedilol in clinically relevant concentrations (3 mg/kg subcutaneously), 4 days before and 3 days after a single radiation dose of 20 Gy significantly decreased the inflammatory reaction in the rat lung, evaluated as number of inflammatory cells in the perivascular area. The density of mast cells was also slightly reduced. In vitro studies revealed that carvedilol caused different radio-protective effects, dependent on dose (1-7 Gy) used and cell line studied. The effects were especially pronounced in a malignant mesothelioma cell line (P-31), and somewhat less evident in a prostatic carcinoma cell line (PC-3). No significant effect was seen in a highly radiosensitive small cell lung cancer cell line (U-1690). Thus, carvedilol may under some circumstances interact with radiation-induced tissue reactions, most probably by a direct interaction at the cellular level. The specific explanation to the differences in sensitivity to carvedilol remains to be evaluated, but the known antioxidative properties and/or scavenging of free radicals of carvedilol may be a plausible mechanism of action. Secondary induced alterations in inflammatory response may also be considered. It is suggested that a potential interaction between drugs such as carvedilol and irradiation should be considered for clinical practice.

Increase in doxorubicin cytotoxicity by carvedilol inhibition of P-glycoprotein activity.

Acquired resistance to chemotherapy is a major problem during cancer treatment. One mechanism for drug resistance is overexpression of the MDR1 (multidrug resistance) gene encoding for the transmembrane efflux pump, P-glycoprotein (P-gp). The calcium channel blocker verapamil has been shown to reverse cellular drug resistance by inhibiting P-gp drug efflux. This study evaluated whether the new antihypertensive drug carvedilol influenced doxorubicin (Dox) cytotoxicity and P-gp activity in a P-gp-expressing cell line compared to a non-expressing subline. Verapamil (10 micromol/L), and even more markedly, carvedilol (10 micromol/L) increased cellular uptake of P-gp-transported calcein of a P-gp-expressing breast cancer cell line (Hs578T-Dox). In the subline (Hs578T) not expressing P-gp, no effects of carvedilol or verapamil on calcein uptake were seen. Carvedilol and verapamil (10 micromol/L) reduced the LD50 (dose which results in the death of half the number of cells) of the Hs578T-Dox subline from 200 mg/L to approx. 10 mg/L Dox, whereas the LD50 of the Hs578T subline was only marginally affected. Carvedilol (10 micromol/L) reduced P-gp activity approximately twice as effectively as verapamil at an equimolar concentration. Carvedilol did not affect pyrogallol cytotoxicity and pyrogallol was without effect on calcein accumulation of the Hs578T-Dox cell line, indicating the lack of antioxidative properties affecting P-gp activity and associated toxicity of the drug. The results suggest that carvedilol has the clinical potential to reverse tumour MDR involving the efflux protein P-gp.

Interactions of cardiovascular drugs with the cytotoxicity induced by epirubicin and irradiation in-vitro.

Vasoactive drugs have been suggested to modulate the cytotoxicity of chemotherapy and radiotherapy. In this study, we have tested whether a number of commonly used vasoactive drugs interact with epirubicin- and radiation-induced toxicity on Chinese hamster fibroblast cell line V-79. The adrenoceptor agonist epinephrine, enchanced die effects of irradiation as measured by cloning capacity. In contrast, epineprine and terbutaline decreased epirubicin cytotoxicity. The beta-adrenoceptor antagonist propranolol and the alpha-antagonist phentolamine, at 100 mumol/l, caused a significant enhancement of epirubicin cytotoxicity. None of the vasoactive drugs showed intrinsic cytotoxic effects. Radiation-induced cytotoxicity was unaffected by propranolol or phentolamine. The calcium channel blocker, verapamil, enhanced the toxicity induced by epirubicin and radiation. These results indicate that vasoactive drugs such as epinephrine, propranolol and phentolamine can interfere with radiotherapy and with anthracycline cytotoxicity. Further studies are warranted before conclusions on the mechanisms of action can be drawn.

Blunted renal sodium excretion during acute saline loading in normotensive men with positive family histories of hypertension.

The natriuretic and intra-arterial blood pressure response to an acute saline load (1000 mL 0.9% NaCl), was studied in normotensive young men with positive (n = 11) and negative (n = 21) family histories of hypertension. The age-matched (36 +/- 5 years) control group with negative family histories of hypertension was subdivided into two groups, one matched for body mass index (BMI) to the subjects with positive family histories of hypertension (n = 10), and another lean control group (n = 11). Baseline blood pressure was significantly higher in subjects with positive family histories of hypertension and in controls matched for BMI as compared with lean controls. Sodium excretion increased in all three groups during the saline infusion, while subjects with positive family histories of hypertension disclosed a diminished natriuretic response as compared with the two control groups. Systolic blood pressure increased significantly during the saline load in subjects with positive family histories of hypertension, while in subjects with negative family histories of hypertension, no significant change in blood pressure was observed. Plasma renin activity, angiotensin II, serum aldosterone, plasma noradrenaline, blood volume, and ouabain-sensitive erythrocyte sodium efflux rate constant did not differ between the three groups at baseline. A significant negative correlation was found between baseline sodium excretion and sodium efflux rate constant in subjects with positive family histories of hypertension. We conclude that the subjects with positive family histories of hypertension exhibit a blunted natriuretic and an exaggerated blood pressure response to an acute saline load as compared with the two control groups with negative family histories of hypertension. This could be of neuronal and/or hormonal origin.

Protection of renal cells against free radical damage in vitro. A morphologic and functional study on human and rabbit kidney cells.

The morphologic and functional effects of free radicals on renal cells in vitro were investigated, as well as the possibility of avoiding them by pretreatment with scavenger enzymes or a xanthine oxidase inhibitor. Cultured human kidney cells, incubated together with a free radical-generating system, with and without protective agents, were examined by light and scanning electron microscopy. The vimentin filament structure of the incubated cells was visualized by immunofluorescence. The membrane function was studied in human kidney cells by using a dye exclusion test and in rabbit kidney slices by determination of the sodium-potassium pump activity. Exposure of the cells to free radicals caused rapid development of severe morphologic lesions, including extensive cytoskeletal disorganization. After pretreatment, only a few cells had similar, although less severe, lesions. The results of the dye exclusion test and indirect evaluation of the sodium-potassium pump activity did not indicate any major damage to the cell membranes after exposure to free radicals.

Increased erythrocyte sodium efflux during overfeeding without evidence of mediation by circulating catecholamines or thyroid hormone.

Ten slightly obese middle-aged men were instructed to increase their energy intake 25% during a period of 1 week, which was preceded by a control period of seven days. Body weight increased by 0.67 kg (SD 0.60) indicating good compliance with the regimen. Transmembrane sodium fluxes were determined with the use of 22Na. The pre-diet erythrocyte sodium content was 9.7 mmol/L (SD 0.8) decreasing to 8.9 mmol/L (SD 1.1) (P less than 0.05) during overfeeding. The Na-efflux rate constant increased from 0.40 h-1 to 0.54 h-1 (P less than 0.05). Urinary excretion of catecholamines and concentrations of catecholamines and insulin in plasma and of thyroxine, triiodothyronine, and reverse T3 in serum did not change. Thus, overfeeding seems to enhance the total Na efflux in erythrocytes from slightly obese men. There were no measurable changes in thyroid hormone or catecholamine levels leaving the regulatory mechanisms unexplained.

Relationship between change in erythrocyte sodium and antihypertensive response to enalapril.

To investigate the effects of enalapril and hydrochlorothiazide on erythrocyte sodium and potassium in relation to their effects on BP, 28 men (mean age 46 years, range 22-64 years) with previously untreated essential hypertension (casual DBP > or = 95 mmHg) were randomised to enalapril (n = 14) or hydrochlorothiazide (n = 14) treatment. BP was also measured intraarterially (brachial artery) and the mean arterial pressure (MAP) recorded. Intraerythrocyte sodium and potassium were measured by flame photometry at baseline and after 26 weeks of active treatment in the hypertensive patients and also in 28 age- and sex-matched normotensive control subjects. There was a significant positive relationship between intra-arterial BP and intraerythrocyte sodium in untreated hypertensives, but there was no significant difference in mean intraerythrocyte sodium or potassium content between hypertensive and normotensive subjects at baseline. The distribution of values of intraerythrocyte sodium, however, differed between hypertensive and normotensive subjects. Supine MAP was lowered from 113 +/- 4 to 97 +/- 3 mmHg and from 110 +/- 3 to 102 +/- 2 mmHg on enalapril and hydrochlorothiazide treatment, respectively. BP reduction with enalapril was associated with a significant decrease in intraerythrocyte sodium (P = 0.02), while hydrochlorothiazide had no effect. There was no significant correlation between delta MAP and delta intraerythrocyte sodium after 26 weeks in any of the groups. Intraerythrocyte potassium did not change on treatment with either drug. In conclusion, there wa a significant relationship between intra-arterial BP and intraerythrocyte sodium in untreated hypertensives. Both enalapril and hydrochlorothiazide reduced BP effectively while enalapril only reduced intraerythrocyte sodium.(ABSTRACT TRUNCATED AT 250 WORDS)

Method for long-term intestinal access in the dog.

A variety of devices have been used to establish long-term intestinal access in laboratory animals. Their use is complicated by infection, tissue reaction, and a frequent need for single housing to prevent implant damage. Intussuscepted nipple valves have long been used in the human field of surgery for various applications where there is a need to create a reservoir without leakage. With the use of the nipple valve it was possible to establish long-term intestinal access in dogs with minimal post-operative complications, no leakage and, because no foreign material was used, no complications due to tissue rejection. The advantages of a nipple valve over the similar technique of a straight stoma is less postoperative complications in the form of leakage as well as enhanced access due to the design of the nipple valve. Encouraging results prompted us to widen the use of nipple valves to 14 dogs in which it has been possible to establish long-term colonic or duodenal/ileal access at one or two sites. Nine of the dogs are still in use with duration of instrumentation for some animals exceeding 60 weeks. This method requires minimal maintenance, does not prevent group housing of instrumented dogs or outdoor activities nor does it compromise the quality of life for the animals.