Muscle mass, muscle strength and mortality in kidney transplant recipients: results of the TransplantLines Biobank and Cohort Study

BACKGROUND

Survival of kidney transplant recipients (KTR) is low compared with the general population. Low muscle mass and muscle strength may contribute to lower survival, but practical measures of muscle status suitable for routine care have not been evaluated for their association with long-term survival and their relation with each other in a large cohort of KTR.

METHODS

Data of outpatient KTR ≥ 1 year post-transplantation, included in the TransplantLines Biobank and Cohort Study (ClinicalTrials.gov Identifier: NCT03272841), were used. Muscle mass was determined as appendicular skeletal muscle mass indexed for height² (ASMI) through bio-electrical impedance analysis (BIA), and by 24-h urinary creatinine excretion rate indexed for height² (CERI). Muscle strength was determined by hand grip strength indexed for height² (HGSI). Secondary analyses were performed using parameters not indexed for height². Cox proportional hazards models were used to investigate the associations between muscle mass and muscle strength and all-cause mortality, both in univariable and multivariable models with adjustment for potential confounders, including age, sex, body mass index (BMI), estimated glomerular filtration rate (eGFR) and proteinuria.

RESULTS

We included 741 KTR (62% male, age 55 ± 13 years, BMI 27.3 ± 4.6 kg/m²), of which 62 (8%) died during a median [interquartile range] follow-up of 3.0 [2.3-5.7] years. Compared with patients who survived, patients who died had similar ASMI (7.0 ± 1.0 vs. 7.0 ± 1.0 kg/m²; P = 0.57), lower CERI (4.2 ± 1.1 vs. 3.5 ± 0.9 mmol/24 h/m²; P < 0.001) and lower HGSI (12.6 ± 3.3 vs. 10.4 ± 2.8 kg/m²; P < 0.001). We observed no association between ASMI and all-cause mortality (HR 0.93 per SD increase; 95% confidence interval [CI] [0.72, 1.19]; P = 0.54), whereas CERI and HGSI were significantly associated with mortality, independent of potential confounders (HR 0.57 per SD increase; 95% CI [0.44, 0.81]; P = 0.002 and HR 0.47 per SD increase; 95% CI [0.33, 0.68]; P < 0.001, respectively), and associations of CERI and HGSI with mortality remained independent of each other (HR 0.68 per SD increase; 95% CI [0.47, 0.98]; P = 0.04 and HR 0.53 per SD increase; 95% CI [0.36, 0.76]; P = 0.001, respectively). Similar associations were found for unindexed parameters.

CONCLUSIONS

Higher muscle mass assessed by creatinine excretion rate and higher muscle strength assessed by hand grip strength are complementary in their association with lower risk of all-cause mortality in KTR. Muscle mass assessed by BIA is not associated with mortality. Routine assessment using both 24-h urine samples and hand grip strength is recommended, to potentially target interdisciplinary interventions for KTR at risk for poor survival to improve muscle status.

[New therapeutic strategies for remyelination in multiple sclerosis]

Multiple sclerosis (MS) is characterized by oligodendrocyte death and myelin sheath destruction of the central nervous system (CNS) in response to autoinflammatory processes. Besides demyelination axonal degeneration constitutes the second histopathological hallmark of this disease. A large number of immunomodulatory and targeted immunosuppression treatments have been approved for relapsing remitting (RR) MS where they effectively reduce relapse rates; however, currently no treatment options exist to repair injured axonal tracts or myelin damage that accumulates over time particularly in progressive MS. In light of the growing available therapeutic repertoire of highly potent immunomodulatory medications there is an increasing interest in the development of therapies aimed at neutralizing neurodegenerative damage. Endogenous remyelination processes occur mainly as a result of oligodendrocyte precursor cell (OPC) activation, recruitment and maturation; however, this repair activity appears to be limited and increasingly fails during disease progression. Based on these observations OPCs are considered as promising targets for the regenerative treatment of all stages of MS. This article presents an overview of approved medications with a suggested role in regeneration, regenerative treatments that are currently being tested in clinical trials, as well as promising future therapeutic approaches derived from basic glial cell research aiming at the promotion of the endogenous repair activity of the brain.

The 2ν(3) Raman overtone of sulfur hexafluoride: absolute spectra, pressure effects, and polarizability properties

Of the six normal vibrations of SF6, ν3 has a key role in the mechanisms of radiative forcing. This vibration, though inactive in Raman, shows up through the transition 2ν3 allowing for a complementary view on the asymmetric stretch of the molecule. Here, we look back into this topic, which has already caught some interest in the past but with some points been left out. We make a systematic incoherent-light-scattering analysis of the overtone with the use of different gas pressures and polarization orientations for the incident beam. Absolute-scale isotropic and anisotropic spectra are reported along with natural and pressure-induced widths and shifts, and other spectral features such as the peaks corresponding to the (experimentally indistinguishable) interfering channels Eg and F2g hitherto seen solely as two-photon IR-absorption features. We make the first-ever prediction of the SF6 polarizability second derivative with respect to the ν3-mode coordinate and we develop a heuristic argument to explain why the superposition of the three degenerate stretching motions that are related to the ν3 mode cannot but generate a polarized Raman band.

From light-scattering measurements to polarizability derivatives in vibrational Raman spectroscopy: the 2ν5 overtone of SF6

The room-temperature isotropic spectrum of SF6 was recorded at the frequency of the 2ν5 overtone by running high-sensitivity incoherent Raman experiments for two independent polarizations of the incident beam and for gas densities varying from 2 to 27 amagat. Weak yet observable pressure effects were found. A transparent analysis of the Raman cross-section problem along with the first-ever prediction of the value of the mean polarizability second derivative ∂(2)α/∂q5(2) are made and the hitherto underestimated role of the hot bands of SF6 is brought to the wider public. The emergence of an analytic hotband factor is shown whose magnitude is dramatically increased with the order of the overtone and the gas temperature and all the more so upon considering low-frequency molecular vibrations. Our formulas, which in the harmonic approximation are exact, are still applicable to real situations provided certain conditions are fulfilled. For nondegenerated modes, generalization to higher order overtones is made, an issue addressing the much challenging problem of the IR-allowed second overtone bands. The content of this paper is also an invitation towards ab initio derivative-calculations for sulfur hexafluoride, especially given the today's needs in interpreting spectra of significance for greenhouse atmospheric issues.

SNP genotyping for detecting the 'rare allele phenomenon' in hybrid zones

Hybrid zones are regions where genetically distinct populations meet, mate and produce offspring. In such zones, genetically less compatible gene combinations are usually generated, resulting in reduced fitness, and hybrid zones are often maintained because of continuous removal of unfit genotypes, balanced by gene flow into the zone from the parental populations (and are then referred to as 'tension zones'). Tension zones often display unexpectedly high frequencies of gene variants that are rare outside the zone. Previous work has shown that this 'rare allele phenomenon' is not the result of intragenic recombination or increased mutation rates. Further understanding of the population genetics of the phenomenon requires an approach in which both the numbers of individuals and the numbers of loci is increased. Here, we report an approach using a combination of Illumina next-generation sequencing and mass spectrophotometer genotyping to identify markers that may be used for genome-wide investigations of the rare allele phenomenon. We test this approach on a hybrid zone in the land snail Albinaria hippolyti from Greece.

Anthraquinone profile, antioxidant and antimicrobial activity of bark extracts of Rhamnus alaternus, R. fallax, R. intermedia and R. pumila

The quantity of phenols, as well as antioxidant and antimicrobial activities, were investigated in bark of Rhamnus alaternus L., R. fallax Boiss., R. intermedia Steud. et Hochst., and R. pumila Turra from natural stands in Croatia. The most abundant anthraquinones in the investigated extracts were chrysophanol in R. alaternus (3.14 mg/g), emodin in R. pumila (0.339 mg/g), and physcion in R. fallax (2.70 mg/g) and R. intermedia (0.285 mg/g). The species exhibiting the highest antioxidant activity were R. fallax and R. pumila. A positive correlation was observed between total phenolic and flavonoid levels of the extracts and antioxidant activity in some of the assays. All species showed antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Aspergillus niger and Microsporum gypseum with minimal inhibitory concentrations equal to or below 2.500 mg/mL. The results indicate that the investigated Rhamnus species are a source of anthraquinones and other phenols, which act as multifunctional antioxidants with antimicrobial activity.

Quantitative measurement of genome-wide DNA methylation by a reliable and cost-efficient enzyme-linked immunosorbent assay technique

DNA methylation, the conversion of cytosine to 5-methylcytosine, is an important epigenetic modification involved in gene regulation. DNA methylation is essential for normal development whereas abnormal methylation has been implicated in pathological conditions including cancer. To evaluate the extent and variation of genome-wide DNA methylation and its changes during cellular differentiation and tumorgenesis as well as the interplay with histone modifications, accurate and reproducible quantification of the genomic DNA methylation level is required. These measurements have so far been achieved only by sophisticated and costly techniques. Here we report the generation of an enzyme-linked immunosorbent assay (methDNA-ELISA) for the accurate quantification of global DNA methylation levels. The linear region of this methDNA-ELISA ranges from 1 to 10%, making it highly suitable for the typical ranges from 2 to 6% in mammalian genomes. This method requires 10 ng of isolated DNA per sample, thus permitting investigation with minimal amounts of DNA previously not applicable for global DNA methylation analysis, e.g., clinical biopsies or cells collected by microdissection.

Hypermethylation at loci sensitive to the prenatal environment is associated with increased incidence of myocardial infarction

BACKGROUND

Human epidemiological studies suggest that small size at birth and food deprivation during gestation confer an excess risk of coronary heart diseases (CHD) in adulthood, frequently in a sex-specific manner. Prior epigenetic studies indicate that such prenatal conditions are marked by persistent and sometimes sex-specific changes in DNA methylation. Here, we have investigated the association between DNA methylation and myocardial infarction (MI) at six loci sensitive to prenatal nutrition, anticipating potential sex-specificity. Method Within the placebo group of the PROSPER trial on pravastatin and the risk of CHD, we compared all individuals who were event free at baseline and developed MI during 3 years' follow-up (n = 122) with a similar-sized control group. Methylation at IL10, LEP, ABCA1, IGF2, INS and GNASAS was measured in DNA extracted from leucocytes using mass spectrometry.

RESULTS

DNA methylation at GNASAS was modestly higher in MI cases compared with controls (P = 0.030). A significant sex interaction was observed for INS (P = 0.014) and GNASAS (P = 0.031). Higher DNA methylation at these loci was associated with MI among women (INS: +2.5%, P = 0.002; GNASAS: +4.2%, P = 0.001). Hypermethylation at one locus and at both loci was associated with odds ratios (ORs) of 2.8 and 8.6, respectively (P(trend) = 3.0 × 10(-4)). No association was observed among men.

CONCLUSIONS

The risk of MI in women is associated with DNA methylation marks at specific loci previously shown to be sensitive to prenatal conditions. This observation may reflect a developmental component of MI.

Intensive treatment in severe acute attacks of ulcerative colitis

The results of intensive treatment including steroids and early surgery in severe colitis in the period 1971-1975 were compared to the results from the period 1966-1970, when systematic intensive therapy was not given. The period of preoperative medical treatment was reduced on average from 31 to 17 days. Approximately half the patients went into remission in each period. In the period 1971-1975 (23 patients) there was no mortality during the acute attacks or in the subsequent follow-up period. In the period 1966-1970, the immediate mortality in 30 patients was 10% (3 patients). One patient died six years later at the age of 81 during a relapse of the colitis, and the overall mortality was 13.3%.

Testing the druggable endothelial differentiation gene 2 knee osteoarthritis genetic factor for replication in a wide range of sample collections

OBJECTIVES

To replicate a previously reported association with osteoarthritis (OA) of the promoter single nucleotide polymorphism (SNP) rs10980705 in the endothelial differentiation gene 2 (EDG2).

METHODS

Five collections of samples, four from Europe and one from China, were studied. They included patients with 3 OA phenotypes: 1501 with knee OA, 1497 with hip OA and 376 with generalised OA. A total of 2521 controls were also studied. Allele and genotype frequencies of the rs10980705 SNP were analysed in each individual sample collection and in pooled data. In addition, a meta-analysis to incorporate results from the original Japanese report was performed.

RESULTS

The association of the rs10980705 SNP with knee OA was not replicated in any of the five sample collections studied or in their combined analysis (odds ratio (OR) 1.10, 95% CI 0.98 to 1.22; p = 0.10). Meta-analysis of all data, including the original Japanese study, did show association with knee OA (OR 1.15, 95% CI 1.06 to 1.26; p = 0.002) but the effect was accounted for by the Japanese data and was less significant than the original report. No association was found with hip OA or with generalised OA.

CONCLUSIONS

The original report of a promising genetic association between a druggable G-protein coupled receptor, EDG2, and knee OA has not been replicated. This lack of replication could be due to a modest effect of the promoter polymorphism that will require even larger studies (the winners curse) although a more pronounced effect in the Asian population vs Europeans cannot be excluded.

Spectrophotometric method for polyphenols analysis: prevalidation and application on Plantago L. species

The prevalidation strategy was applied to evaluate UV-vis spectrophotometric procedure with Folin-Ciocalteu's reagent for polyphenols determination. Favourable prevalidation characteristics verified this procedure as a valuable tool in polyphenols analysis and it was successfully applied for determination of total polyphenols and tannins in leaves, stems and flowers of Plantago L. species growing in Croatia. The results showed the variety of total polyphenols content between different plant parts (leaves: up to 10.15%; stems: up to 4.34% and flowers: up to 5.56%). The content of tannins in stems was from 0.28% to 1.00%, while leaves and flowers contained tannins in concentrations of 2.26% and 2.21%, respectively. The results of polyphenols determination were evaluated by using multivariate analysis (UPGMA and PCA) as a contribution to elucidation of relations between different taxa of genus Plantago L.

Physical activity programs offered in substance abuse treatment facilities

Responses from 50 practicing therapeutic recreation specialists indicate that physical activity programs are an important part of substance abuse treatment. Walking, games, sports, weight training, and aerobics were offered most frequently. Respondents expressed concern about their academic preparation in physical activities and offered suggestions for curricular revision. Recreation or activity therapists responding to this survey indicated that additional coursework would have prepared them more thoroughly to facilitate physical activity programs. Coursework suggested included: physical education, exercise programming, aerobics, aquatics, and physical assessment. Data indicated that over half the respondents received specialized training in physical activities after graduation through continuing education.

[Enzyme digestion of autologous cartilage transplants. New possibilities for vital cryopreservation?--Initial results]

The use of autologous cartilage grafts is one of the most common procedures in plastic surgery. Commonly used chemical preservation procedures of the cartilage for a second operation usually lead to the loss of vitality of the graft. In the past few years cryopreservation methods were used in the maintenance of the vitality of the autologous grafts, although these efforts yielded a low vitality of the grafts. It seems that the matrix of the grafts is mainly responsible for the unsuccessful cryopreservation of cartilage. In this work we tried to degrade the matrix of the cartilage grafts by partial enzymatic digestion with collagenase type II and hyaluronidase to facilitate the penetration of dimethylsulfoxide (DMSO). Cell vitality was assessed by trypan dye exclusion. We could demonstrate that it is possible to raise the permeability of the matrix by enzymatic digestion. Cryopreservation of the digested cartilage yielded a vitality of nearly 20%. Our results suggest that pretreatment of cartilage grafts with specific enzymes before preservation enable more successful vital cryopreservation.

Determination of viability of cryopreserved cartilage grafts

Although transplantation of preserved cartilage has assumed a role of great importance in reconstructive surgery, there are many divergent and contradictory opinions with regard to the outcome of cryopreserved cartilage. This study was formulated to assess the functional state of chondrocytes after cryopreservation. Freeze injury and survival were studied using the trypan blue dye exclusion test, functional assay for cell adhesion and transmission electron microscopy. The methods applied clearly proved that a greater part of the cartilage cells was irreversibly damaged by cryopreservation. Findings demonstrated that cryopreserved cartilage remained non-viable and was not able to originate new cartilage. Thus, such cartilage will be subject to resorption processes and not practical for reconstruction of parts of the skeleton subject to mechanical stress. The feasibility of cryopreservation techniques for providing vital cartilage substitutes needs further evaluation.

[Effects of ultrasound energy on femoral artery occlusion. Angiographic and angioscopic results]

Ultrasonic energy has been shown to be able to disrupt atherosclerotic plaques and thrombi. The authors used an ultrasonic angioplastic technique developed by the group in 10 patients with a femoral arterial occlusion. The ultrasonic angioplasty was attempted before surgical bypass using a 130 cm long titanium guide wire with a 0.8 mm diameter and a round distal tip measuring 2 or 2.5 mm. Angiographic and angioscopic examinations were performed before and after the procedure in 9 patients. It was not possible to perform the angioplasty in 1 patient. Angioscopy showed that the proximal part of the occlusion consisted of atheromatous material in 3 cases and of thrombus in 6 cases. Angiography showed complete restoration of flow in 4 cases; distal flow was very slow in 4 cases and no distal run-off was observed in 1 case. Angioscopy showed residual stenosis at the site of entry in only 1 case. In 3 cases, the artery had no significant residual stenosis. In the other 5 patients residual stenosis was present and angioscopy showed persistence of strands of fibrin and small thrombi. These results show that ultrasonic angioplasty was capable of recanalising an occlusion in 9 out of 10 patients with partial or total disruption of thrombi. At the present stage of development of this system, balloon angioplasty would be an essential complement in most cases in order to obtain normal flow without significant residual stenosis. The manoeuverability of the guide wire and the relatively small size of the round distal tip explain why not all the thrombi could be treated.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of ultrasound energy on total peripheral artery occlusions: initial angiographic and angioscopic results

Ultrasonic energy has been shown to ablate atherosclerotic plaques and arterial and venous thrombi. We used an ultrasonic angioplasty device developed by our group in ten patients with totally occluded femoral artery during surgical bypass. Ultrasonic angioplasty was performed with a 130-cm long and 0.8-cm diameter titanium probe with a 2- or 2.5-mm titanium ball-tip. In one patient, angioplasty could not be performed. Angiographic and angioscopic examination were performed before and after angioplasty in nine patients. Before ultrasound recanalization, angioscopic examination showed that the proximal end of the occlusion was formed by atheromatous material in 3 cases, red thrombus in 3 cases, amd white thrombus in 3 cases. After ultrasound recanalization, angioscopy showed residual stenosis at the site of entry in only one case. In three other cases, the artery was free of residual stenosis without persistent clot. In the five other patients, a residual stenosis was present beyond the proximal occlusion point with some fibrin mesh and small clots. At angiography, flow was restored in 4 cases; in 4 patients flow rate of entry was slow in the distal segment; and in 1 patient, the distal arterial bed could not be opacified. Altogether, ultrasonic angioplasty was able to recanalize a complete occlusion in nine out of ten patients, with partial or complete dissolution of clots and with no complication. At its present stage of development, adjunctive balloon angioplasty would be needed in most cases to obtain unrestricted flow and unsignificant residual stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effects of ultrasonic energy on blood clots in vitro]

Ultrasound may be used to dissolve arterial and venous thrombi. Its effects depends on the mode of ultrasonic vibration and on the length of the guide wire. The authors studied the in vitro effects of an ultrasonic angioplasty device coupled with a 130 cm long titanium flexible guide wire. The system comprises an automatic scanning function to determine the optimal frequency of resonance and works in the continuous mode of emission. Sixteen thrombi were studied of which 8 were acellular and 8 whole blood. In each group, 4 were treated in association with streptokinase and 4 by ultrasound alone. The ages of the thrombi in each subgroup were 1, 3, 7 and 15 days. All the thrombi were dissolved in 6 minutes or less (3'15" +/- 1'35") at an average optimal frequency of resonance of 19,444 Hz. Ninety six per cent of the debris had a diameter less than 10 microns. Less than 1% of the debris had a diameter larger than 100 microns. These large particles were observed in cellular thrombi and were almost completely absent in dissolved acellular thrombi. They were very fragile. The dissolution of the thrombi was not accelerated by the association of streptokinase. The ultrasonic energy did not induce D-dimer production and its action was probably due to cavitation. Ultrasonic energy could provide an alternative treatment for thrombotic vascular occlusion provided that more flexible guide wires could be designed.

Effects of ultrasound energy on thrombi in vitro

Ultrasonic energy may be used for dissolution of venous or arterial thrombi. However, its effects may depend on the mode of ultrasonic vibration and on the length of the probe. We investigated the in vitro effects of an ultrasonic angioplasty device coupled with a 130 cm-long flexible titanium probe, with an incorporated automatic optimal frequency of resonance scanning function and continuous mode of emission. Sixteen clots were treated of which eight were whole blood and eight cell-free. In each of these groups, four were treated in association with streptokinase and four by ultrasound alone. The ages of the clots in these subgroups of four were 1, 3, 7, and 15 days. All thrombi were dissolved in 6 min or less (3'15" +/- 1'35") at a mean optimal frequency of resonance of 19,444 Hz. Ninety-six percent of the debris were less than 10 mu. Fewer than 1% of the particulates were larger than 100 mu. These large particulates were observed in disrupted whole blood clots and were almost non-existent in disrupted cell-free clots. They were very fragile. Clot dissolution was not speeded by adding streptokinase to ultrasound. Ultrasound did not induce D-Dimer production, and its effect was most likely to be due to cavitation. Ultrasound energy could represent an advance for thrombotic vascular occlusion therapy, provided that more flexible probes can be devised.

Calcium-regulating hormones in hypertension: vascular actions

The vascular and potentially hypertensive actions of the calcium-regulating hormones 1,25-dihydroxychole-calciferol [1,25(OH)2D3], parathyroid hormone (PTH), and calcitonin and related factors such as parathyroid hypertensive factor (PHF) and calcitonin gene-related peptide (CGRP) are discussed. 1,25(OH)2D3 has inotropic and calciotropic actions on isolated vascular tissue whereas PTH is a vasodilator. PHF, which has been reported in plasma of humans with essential hypertension and spontaneously hypertensive rats, has both pressor and calciotropic actions. Calcitonin is without vascular effects and CGRP is a potent vasodilator. It is concluded that several of the hormones responsible for maintaining Ca2+ homeostasis modulate vascular Ca2+ metabolism and force generating capacity. These substances may be long-term modulators of vascular function and play a role in the determination of peripheral vascular resistance.

Fatal cytomegalovirus (CMV) colitis in a patient receiving low dose prednisolone therapy

Cytomegalovirus (CMV) colitis is uncommon in patients who are not gravely immunodepressed. We report a case of fatal CMV colitis in a 54-year-old woman on low dose steroid therapy. She was admitted to hospital after sudden onset of abdominal pain and hemorrhagic watery diarrhea. After 25 days in the hospital, treatment with high dosage of methylprednisolone was started for presumed ulcerative colitis. Her condition worsened and she died 52 days after admission. It is important to recognize CMV colitis as differential diagnosis to inflammatory bowel disease, particularly when the colitis is refractory to immunosuppressive treatment.

[Development of an ultrasonic system for the recanalization of coronary arteries]

We have devised an electro-acoustic system for the production and propagation of ultrasounds. With this system, linear vibrations can be transmitted through guides that are routinely used for coronary dilatation. Experiments performed on anatomical specimens have shown that ultrasounds are effective in destroying atheromatous formations. In addition, we tested this effectiveness with a setting that modelled the use of this system on the coronary vessels in terms of prerequisites: presence of a carrying catheter, aqueous environment, attention to vascular sinuosities and protection of arterial walls. The biological safety of low-frequency ultrasounds was tested in vitro and in animals. In view of these preliminary results, the subsequent development of an electro-acoustic system to be used in man seems to be justified.

Angiotensin-induced myocardial necrosis and renal failure in the rabbit: distribution of lesions and severity in relation to plasma angiotensin II concentration and arterial pressure

Angiotensin II was infused into conscious rabbits at various doses from 0.001 to 0.5 microgram . kg-1 . min-1 for 24 h, and caused multifocal myocardial necrosis, renal tubular necrosis and acute renal failure. The myocardial necroses were found principally in the left ventricle; only at the highest doses of angiotensin II were right ventricular lesions present. The endocardium was not involved and no arterial or arteriolar lesions were seen. Mean arterial plasma angiotensin II concentration during angiotensin infusion was closely correlated with the increase in arterial pressure, the height of the plasma urea at the end of the infusion and the severity of the induced myocardial lesions. The myocardial necroses could be a consequence of the induced hypertension, or a direct effect of angiotensin II, or a combination of effects, although their predominance in the left ventricle suggests high systemic arterial pressure is an important factor. Cardiac lesions were observed with plasma angiotensin II concentrations only some 2 to 3 fold normal values; it is therefore possible that similar myocardial abnormalities might occur as a result of rises in endogenous renin, for example, in experimental or clinical renovascular hypertension.

Amiloride in the treatment of primary hyperaldosteronism and essential hypertension

Amiloride (40 mg/day) was given to nineteen patients with primary hyperaldosteronism. There were significant falls in systolic and diastolic blood pressure, in total exchangeable sodium, and in serum sodium sodium and bicarbonate; while total exchangeable potassium, total body potassium, serum potassium, chloride and urea, and plasma renin, angiotensin II and aldosterone all increased significantly. Amiloride was effective in reducing blood pressure in patients with and without adrenocortical adenoma. No carry-over effect was seen on withdrawing amiloride. Similar changes were associated with amiloride treatment in five patients with essential hypertension; hyperkalaemia was not observed. Only negligible side-effects were encountered in the entire series of twenty-four patients.

Angiotensin- and norepinephrine-induced myocardial lesions: experimental and clinical studies in rabbits and man

The ability of large doses of exogenous angiotensin II to cause widespread multifocal microscopic myocardial necrosis in the rabbit has been confirmed. Angiotensin II also consistently produced acute renal failure with, less consistently, renal tubular necrosis. Norepinephrine infusions caused histologically indistinguishable myocardial lesions, but did not detectably affect renal function or histology. Severe renal failure, induced by bilateral nephrectomy (with or without concurrent glycerol administration) was not associated with similar cardiac lesions. Acute renal failure of comparable or greater severity to that induced by angiotensin II was produced by intramuscular cephaloridine, and was not associated with cardiac lesions. Rabbits infused with saline intravenously or "sham"-operated by simply opening and closing the peritoneal cavity did not develop renal failure and showed no cardiac or renal lesions histologically. Myocardial lesions, apparently identical to those seen in the rabbits, were observed postmortem in three patients known to have had high circulating levels of angiotensin II before death, although in all three cases alternative explanations are possible. Unexplained arrhythmia, cardiac arrest, and central chest pain without clear cardiographic or serum enzyme evidence of myocardial infarction occurred in two other subjects with very high plasma levels of angiotensin II. These attacks ceased after bilateral nephrectomy and a consequent fall in plasma angiotensin II. The cardiac attacks in these five patients all occurred during or shortly after procedures, such as sodium-depleting dialysis, renal artery surgery, or diazoxide administration, known to cause increase in plasma concentrations of renin and angiotensin II.

Spironolactone and amiloride in the treatment of low renin hyperaldosteronism and related syndromes

1. Prolonged treatment with spironolactone in low-renin hyperaldosteronism invariably corrects plasma electrolyte abnormalities and usually lowers blood pressure.

2. Total exchangeable sodium, total body water, extracellular fluid and plasma volumes are reduced; total exchangeable and total body potassium, plasma renin and angiotensin II concentrations are increased.

3. Spironolactone is similarly effective in patients with apparently isolated deoxycorticosterone (DOC) excess; also in suspected mineralocorticoid excess not associated with elevation of aldosterone or DOC.

4. Studies of amiloride reveal similar effectiveness to spironolactone in low-renin hyperaldosteronism and in suspected mineralocorticoid excess.

A function of synovial membrane of normal and diseased humans in relation to the movement of small-molecular-weight ions

1. In a series of thirteen patients with rheumatoid arthritis and eleven control subjects clearance rates of 133Xe and 99mTc from the knee joint were monitored before and after oral administration of the anion-transport inhibitor potassium perchlorate.

2. The clearance rate of 99mTc was reduced following perchlorate administration although there was no change in the 133Xe clearance rate. This suggests the presence of a perchlorate-blockable anion-transport mechanism across the synoviocyte.

Amiloride in primary hyperaldosteronism with chronic peptic ulceration

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