Effect of natural early menopause on bone mineral density

OBJECTIVES

Early menopause (EM) is included among the risk factors for osteoporosis. Several studies have shown that women with early menopause have lower bone mineral density (BMD) than those with normal expected age of menopause. The aim of our cross-sectional study was to investigate the effects of time of menopause on vertebral bone mass in healthy postmenopausal women and to evaluate if early menopause is a risk factor for lower vertebral BMD.

METHOD

We studied 782 who had never received drugs acting on bone mass. The study population was divided into three groups: women with early, normal (NM), and late (LM) menopause. Our study population was further categorized in 5-year age segments between 45 and >75.

RESULTS

The three groups examined did not differ for age, age at menarche, body mass index (BMI), and vertebral BMD, while there were significant differences in age at menopause and years since menopause. Our study showed that women with EM presented significantly lower vertebral BMD than NM and LM in 50-54 age segments. Beyond 55 years, EM, NM, and LM women had no differences in lumbar BMD values.

CONCLUSIONS

In conclusion, controversial data demonstrated that the absolute amount of bone loss is greater after early menopause than after normal or late menopause, even if a slight effect of early menopause on bone mass cannot be excluded.

Dimorfismo sexual da traquéia e siringe de periquito (Touist sp.)

Investigaram-se as diferenças morfológicas da siringe do periquito Touist sp, cinco machos e cinco fêmeas. A traquéia e a siringe foram dissecadas com o auxílio de uma lupa estereoscópia e avaliaram-se o número de anéis, o comprimento da traquéia e da siringe e o comprimento e espessura do músculo traqueolateral. A traquéia do macho apresentou maior número de anéis e maior comprimento que a das fêmeas. O músculo traqueolateral dos machos é mais vigoroso e origina-se no 43º anel traqueal enquanto o das fêmeas origina-se no 30º anel traqueal e se insere no primeiro anel bronquial. A siringe do piriquito é constituída por anéis craniais, cinco nos machos e três nas fêmeas, anéis intermediários, com formato semelhante a uma bolha sulcada ventralmente, anéis caudais, quatro em ambos os sexos, e pessulo. O dimorfismo sexual está presente na morfometria da musculatura e das cartilagens, o que reflete no canto mais vigoroso dos machos.

Morphometric study of Rynchotus rufescens testis throughout the year

The research aimed to study the morphologic variation of the testis, seeking to promote the selection and genetic control of those that present appreciable spermatic production throughout the year. Testis morphology of the Rynchotus rufescens partridge was investigated, analyzing the testis weight, the seminiferous tubules diameter, the thickness of the seminiferous epithelium, the amount of meiotic figures and the thickness of the tunica albuginea. Sixty male partridges were used, divided in 12 groups, and one group per month had the testis collected for the histological routine and the sections were stained using the Hematoxilin-Eosin technique. For the histological sections analysis, morphometric measures were taken, with the aid of an Image Analyzer and the resulting data were submitted to analysis of variance and to Tukey's test. Based on the histological modifications of the seminiferous epithelium and the morphometric analysis, the partridge testis morphology could be divided in four successive phases throughout the year. The reproductive phase occurred in the spring, characterized by the complete spermatogenesis process. The regression phase occurred in the summer, with the involution of the seminiferous epithelium. The rest phase took place in the fall, with spermatogonias presence and some spermatocytes beginning the meiosis. The phase of recrudescence occurred in the winter, with the recovery of the seminiferous epithelium and absence of spermatozoa. In conclusion, the characteristics analyzed revealed a variation over the year, with greater production of spermatozoa in the spring and less in the winter.

Platelet-leukocyte interactions in hemodialysis patients: culprit or bystander?

The formation of circulating platelet-leukocyte complexes has been observed in a variety of conditions and may be pathophysiologically significant. Platelet-leukocyte interactions in fact facilitate metabolic cooperation and mutual activation, which may be of relevance in many biological processes including inflammation, atherogenesis and hemostasis. During hemodialysis procedure, the series of reactions that can occur upon blood contact with the foreign membrane surface may involve a variety of changes affecting almost every cellular and plasmatic component of the blood. This article reviews the evidence for abnormal interactions between circulating platelets and leukocytes in uremic patients undergoing maintenance hemodialysis and the pathophysiologic implications which may stem from such interactions.

Wireless capsule endoscopy in the diagnostic of small intestine angiodysplasia in chronic uremic patient

Gastroenteric bleeding due to angiodysplasia (AD) is a relatively common occurrence in patients with end-stage renal failure. Gastric and colon angiodysplasic lesions can be easily revealed by endoscopic procedures, whereas lesions of the small intestine are more difficult to detect. Imaging modalities used in the diagnostic imaging algorithm for the detection of small-bowel AD, include non-invasive methods like enema-helical computer tomography,(99m)Tc-labelled red blood cell scintigraphy, and angiography, and invasive methods such as intraoperative enteroscopy. We report the cases of 3 hemodialysis patients with recurrent episodes of gastrointestinal bleeding, caused by small-bowel AD diagnosed by means of wireless-capsule endoscopy. In all cases, previous gastroscopy and colonoscopy were unrevealing. Wireless-capsule endoscopy consists in swallowing a capsule endoscope (11 mmx27 mm) which contains a miniature video camera, a light source, batteries, and a radio transmitter. Video images are transmitted by means of radio telemetry to aerials taped to the body that allow images to be captured. Moving images from a period as long as 6 h are stored on a portable recorder. Wireless-capsule endoscopy may prove valuable in the assessment of gastrointestinal bleeding in uremic patients with unrevealing results at gastroscopy and colonoscopy.

[On-line HFR and removal of uremic toxins inducing the loss of phospholipidic asymmetry of the erythrocyte membrane]

The phospholipids of the erythrocyte membrane are normally distributed asymmetrically in the double layer with the aminophospholipid phosphatidylserine (PS) present only on the inside of the membrane, since its exposure on the outside has numerous physiopathological consequences. In previous studies we have observed that solutes retained in uremia cause increased exposure of PS on the outer surfaces of the erythrocyte membrane and that this phenomenon may be involved in the uremic physiopathology, reducing erythrocyte survival and encouraging abnormal erythrocyte-endothelium interactions. The capability of the extracorporeal blood clearance treatment in removing the circulating uremic factors, responsible for the increased exposure of PS in red blood cells (RBC), was evaluated in 6 chronic uremic patients treated with haemodialysis (HD) or with on-line HFR in a random cross-over perspective study. The PS removal was evaluated indirectly by measuring the expression of PS in normal RBC incubated with uremic plasma obtained at various moments of the clearance session. The capability of the uremic plasma to expose PS on the RBC of healthy subjects (n-times increase compared to incubation of normal RBC with autologous plasma) was essentially unmodified during HD (3.3 +/- 0.2 pre HD; 3.3 +/- 0.1 after 2 hours; 3.1 +/- 0.2 at the end of the session) but was reduced during HFR (3.1 +/- 0.2 pre HD; 2.3 +/- 0.1 after 2 hours; 1.6 +/- 0.1 at the end of dialysis; p<0.001 at the end of dialysis vs pre and after 2 hours and p<0.001 vs HD at 2 hours and at the end of the session). The reduced capability of the uremic plasma obtained during the HFR session to expose PS in normal RBC, proves removal of the plasmatic uremic factors able to externalize the PS. To assess whether this removal effect is linked to the cartridge containing styrene resin used in the treatment with HFR, samples of ultrafiltrate were taken before and after the cartridge and its capability to express PS on normal RBC was measured. The absolute RBC values expressing PS (%) were (pre-cartridge vs post-cartridge) 8.6 +/- 0.3 vs 3.8 +/- 0.2 after 5 minutes from the start of the session; 3.9 +0.1 vs 1.6 +0.2 halfway through the session; 3.1 +/- 0.1 vs 1.3 +/- 0.66 at the end of the session (p<0.005 pre vs post at all times). Our results show that uremic compounds able to cause increased exposure of PS in RBC can be removed during on-line HFR, mainly thanks to the adsorption properties of the cartridge containing resin. This removal might be of benefit to uremic patients, improving the anaemic condition and reducing abnormal RBC-endothelium interactions which may contribute to endothelial disorder during uremia.

Increased platelet phosphatidylserine exposure and caspase activation in chronic uremia

Platelet activation is associated with exposure of the aminophospholipid phosphatidylserine (PS) to the outer hemi-leaflet of the plasma membrane bilayer, which seems to be involved in the coagulation process. Because platelet activation may occur in patients suffering from chronic uremia, which is frequently associated with a thrombophilic tendency, we studied whether uremic platelets show an increased propensity to expose PS on the outer membrane leaflet and whether this process is linked with important functional and molecular changes. Flow cytometric percentage of annexin V-positive platelets, a measure of PS externalization, was significantly elevated (P < 0.001) in uremic patients when compared to normal controls under both unstimulated and agonist-stimulated conditions. Uremic platelet procoagulant activity, as measured by thrombin generation, was more than twice as high (4.13 +/- 0.3 micro mL(-1)) as that found in normal controls (1.86 +/- 0.2 micro mL(-1)). Two independent assays showed that the enzymatic activity of caspase-3, a protease involved in the loss of membrane PS asymmetry, was significantly greater in the platelets of uremic subjects than in those of healthy controls. PS exposure in agonist-stimulated platelets was markedly reduced by inhibition of caspase-3 activity but was not affected by inhibition of calpain activity. These results support the view that the thrombophilic susceptibility of uremic patients may be partly ascribed to increased PS exposure to the outer membrane leaflet of platelets. This process seems to be causally linked to an increase in caspase-3 activity, particularly during platelet activation.

[Russell's syndrome: a case of long-term survival and review of the literature]

We report the case of a two years old, normally eating child, affected by organic macies and severe dystrophy. After the negative response of blood and laboratory examinations let us exclude a malabsorption syndrome, only the performance of neuro-radiologic exams showed evidence of a subthalamic tumor as the cause of a "Diencephalic syndrome". Diencephalic syndrome or Russell's syndrome is a diencephalic tumor induced disease, which sets in the first time of life. The disease clinical markers are a severe emaciation with appetite preservation and absence or very scarce evidence of any telltale neurological sign. The tumoral histo-pathology most frequently shows a low grade of malignancy astrocytoma, whose eradication is very often difficult because of particular anatomic site. Treatment of choice includes an excisional biopsy with chemotherapy and radiotherapy. We report a clinical case of long-term survival and review of the literature.

Cell activation and cellular-cellular interactions during hemodialysis: effect of dialyzer membrane

During hemodialysis (HD), circulating blood cells can be activated and also engage in dynamic interplay. These phenomena may be important factors behind dialysis membrane bio(in)compatibility. In the present prospective cross-over study, we have used flow cytometry to evaluate the influence of different dialysis membranes on the activation of circulating blood cells (leukocytes, platelets) and their dynamic interactions (formation of circulating platelet-leukocyte and platelet-erythrocyte aggregates) during in vivo HD. Each patient (n = 10) was treated with dialyzers containing membranes of cellulose diacetate, polysulfone and ethylenevinylalcohol (EVAL) in a randomized order. Upregulation of adhesion receptor expression (CD15s, CD11b/CD18) occurred mainly with the cellulosic membrane, though an increase in CD11b/CD18 circulating on neutrophils was also found with both synthetic membranes. Circulating activated platelets (P-selectin/CD63-positive platelets) increased during HD sessions with cellulose diacetate and polysulfone. An increased formation of platelet-neutrophil aggregates was found at 15 and 30 min during dialysis with cellulose diacetate and polysulfone but not with EVAL. Platelet-erythrocyte aggregates also increased with cellulose diacetate and at 15 min with polysulfone as well. Generally in concomitance with the increase in platelet-neutrophil coaggregates, there was an increased hydrogen peroxide production by neutrophils. The results of this study indicate that cellular mechanisms can be activated during HD largely depending on the membrane material, EVAL causing less reactivity than the other two membranes. It appears that each dialysis membrane has multiple and different characteristics that may contribute to interactions with blood components. Our results also indicate that derivatizing cellulose (cellulose diacetate) may be a useful way to improve the biocompatibility of the cellulose polymer and that there may be great variability in the biocompatibility profile of synthetic membranes, dialysis with polysulfone being in general associated with a higher degree of cell activation than EVAL membrane.

[Acute pulmonary edema with pseudohypotension]

A 69-year-old male was admitted to our Coronary Care Unit because of increasing dyspnea in a non-Q wave myocardial infarction complicated by severe heart failure. Physical examination revealed dyspnea, cyanosis, sweat, bilateral crepitations on the whole chest and severe hypotension (blood pressure 80/40 mmHg on the left arm and 90/55 mmHg on the right arm). A coronarographic examination was performed as the patient's clinical status worsened despite an appropriate treatment of the hemodynamic impairment with vasoactive drugs. It showed no hemodynamically significant coronary stenosis and an elevated left ventricular systolic pressure (180/200 mmHg). An obstruction of the vascular district of both arms was diagnosed as the underlying cause of such relevant difference between the left ventricular and humeral blood pressures. A computed tomographic spiral scan of the chest confirmed the presence of a bilateral subclavian artery from the aortic arch and an atheromatous substenosis of the right subclavian artery. The subsequent evaluation of the blood pressure at the lower limbs showed values of systolic blood pressure > 220 mmHg, while the values at upper limbs were persistently < 90 mmHg. In conclusion, careful evaluation of the blood pressure at all four limbs is necessary in all patients with suspected peripheral vascular disease in which a single determination may be misleading.

One percent sodium carboxymethylcellulose prevents experimentally induced abdominal adhesions in horses

OBJECTIVE

To evaluate the efficacy of 1% sodium carboxymethylcellulose (SCMC) for prevention of experimentally induced abdominal adhesions in horses.

STUDY DESIGN

Prospective, controlled, experimental study.

ANIMAL POPULATION

Twelve healthy adult horses.

METHODS

The effect of 1% SCMC on adhesion formation was evaluated in 12 healthy horses by using an established model of serosal trauma to induce intraabdominal adhesions. After ventral median celiotomy, 2 separate areas of the jejunum were abraded, and three 2-0 chromic gut sutures were placed in each abraded area. Jejunal resection and end-to-end anastomosis was performed at 2 sites distant to the abrasion sites. In treated horses (n = 6), 2 L of 1% SCMC was applied to the intestine before and after intestinal manipulation. In control horses (n = 6), 2 L of saline solution were applied to the intestine before and after surgical manipulation. All horses were euthanatized 10 days after surgery, and the abdominal cavity was evaluated for adhesion formation. The frequency of intraabdominal adhesions between groups was compared with a chi-square test. Statistical significance was set at P <.05.

RESULTS

All control horses had intraabdominal adhesions. Fibrous adhesions were associated with both jejunal abrasion sites in 5 control horses. Fibrous adhesions were also associated with 1 or both jejunal anastomotic sites in 5 control horses. Only 1 treated horse developed adhesions at the jejunal abrasion sites, and no adhesions were present at the anastomotic sites in the treated horses. There were significantly fewer adhesions in the SCMC treatment group compared with the control group (P <.05).

CONCLUSION

In this experimental model, application of 1% SCMC reduced the frequency of intraabdominal adhesions at areas of serosal abrasion and at jejunal anastomotic sites.

CLINICAL RELEVANCE

In horses at an increased risk for developing intraabdominal adhesions after intestinal surgery, the use of 1% SCMC during celiotomy may decrease the frequency of adhesion formation.

Biocompatibility and functional performance of a polyethylene glycol acid-grafted cellulosic membrane for hemodialysis

In order to improve the biochemical reactivity of the cellulose polymer, which is mainly attributed to the presence of surface hydroxyl groups, derivatized cellulosic membranes have been engineered replacing or masking some or all of the hydroxyl groups in the manufacturing process of the membrane. The present study was set up to analyze both biocompatibility and functional performance of two different derivatized cellulosic membranes (cellulose diacetate; polyethylene glycol, PEG, acid-grafted cellulose) as compared to a synthetic membrane (polymethylmethacrylate, PMMA). Cellulose diacetate is prepared by substituting hydroxyl groups with acetyl groups; PEG cellulose is obtained by grafting PEG chains onto the cellulosic polymer with a smaller amount of substitution than cellulose diacetate. While the three dialyzers provided similar urea and creatinine removal, the dialyzer containing cellulose diacetate showed a reduced ability to remove 32-microglobulin compared to that containing PEG cellulose or PMMA. A transient reduction in leukocyte count was observed for both derivatized cellulosic membranes. The neutrophil and monocyte counts throughout the entire dialysis session showed a closer parallelism with the cellular expression of the adhesive receptor CD 15s (sialyl-Lewis x molecule) than with CD11b/CD18 expression. Platelet activation, as indicated by the percentage of cells expressing the activation markers CD62P (P-selectin) and CD63 (gp53), occurred with all membranes at 15 min of dialysis and also with PMMA at 30 min. An increased formation of platelet-neutrophil and platelet-monocyte coaggregates was found at 15 and 30 min during dialysis with cellulose diacetate and PMMA but not with PEG cellulose. Generally in concomitance with the increase in platelet-neutrophil coaggregates, an increased hydrogen peroxide production by neutrophils occurred. Our results indicate that derivatizing cellulose may represent a useful approach to improve the biocompatibility of the cellulose polymer, though some homeostatic reactions remain activated. Our results also indicate that there may be a great variability in the biocompatibility profile of derivatize cellulosic membranes which most likely stem from the different type of structural modification rather than from the degree of hydroxyl group replacement.

[Comparison of mammographic and industrial films in dialysis patients]

PURPOSE

To optimize the technique for radiographic studies of bone and joint damage in renal osteodystrophy.

MATERIAL AND METHODS

Sixty-four patients with chronic renal failure on dialysis for 0-10 years, were divided into two homogeneous groups and submitted to two different radiographic examinations of the nondominant hand. Group A patients were examined with a conventional radiological unit and an industrial film and a conventional radiological unit with a mammographic film with a dedicated screen, while group B patients with a mammographic with an industrial film and a conventional radiologic unit with a mammographic film with a dedicated screen. The examinations were evaluated by three radiologists in a double-blind fashion.

RESULTS

Bone conditions such as osteoporomalacia, trabecular rarefaction, channel enlargement and intracortical absorption were equally demonstrated by mammographic films and the mammograph with industrial films. The mammographic film was superior to the mammograph with an industrial film in 8 cases, comparable in 25 and inferior in 6, but when compared with the conventional radiological unit with an industrial film it was superior in 19 cases, comparable in 2 and never inferior.

CONCLUSIONS

The industrial film without a screen combined with a mammograph is considered the gold standard to study fine bone alterations in renal osteodystrophy. However the conventional radiological unit with a mammographic film with a dedicated screen provides the same results with lower irradiation doses and can therefore be considered a good alternative.

Evaluation of a bioresorbable hyaluronate-carboxymethylcellulose membrane for prevention of experimentally induced abdominal adhesions in horses

OBJECTIVE

To evaluate the efficacy of a bioresorbable hyaluronate-carboxymethylcellulose membrane (HA-membrane) for prevention of experimentally induced abdominal adhesions in horses.

STUDY DESIGN

Experimental study.

ANIMAL POPULATION

Twelve healthy adult horses.

METHODS

The effect of an HA-membrane on adhesion formation was evaluated in 12 healthy horses using an established model of serosal trauma to induce adhesions. A ventral median celiotomy and two jejunal resections and end-to-end anastomoses were performed. Two separate jejunal areas were abraded, and three 2-0 chromic gut sutures placed in the abraded areas. In treated horses (n = 6), HA-membranes were applied to the jejunum to completely cover the anastomoses and abraded areas of jejunum. Nontreated horses (n = 6) served as controls. All horses were killed 10 days after surgery. The abdominal cavity was evaluated for adhesion formation. The frequency of intra-abdominal adhesions between groups was compared with a chi2 test with statistical significance set at P < .05.

RESULTS

All control horses had intra-abdominal adhesions; fibrous adhesions were associated with both jejunal abrasion sites in 5 horses. One treated horse developed adhesions. There were significantly fewer adhesions in the HA-membrane-treated group (P < .0034).

CONCLUSIONS

In this experimental model, application of an HA-membrane to a localized area of serosal trauma reduced the frequency of intra-abdominal adhesion formation.

CLINICAL RELEVANCE

Application of an HA membrane may decrease the frequency of adhesions in horses at an increased risk of postoperative adhesion formation.

Leukocyte adhesion molecules and leukocyte-platelet interactions during hemodialysis: effects of different synthetic membranes

Membranes made from synthetic polymers, in general, are considered as being biocompatible membranes and tend to be treated as a homogeneous group. However, all of these membranes have multiple and different characteristics that may contribute to interactions with blood components. As a consequence, the biocompatibility profile of synthetic membranes may vary. In the present cross-over study, we examined by flow cytometry the effects (expressed as % change from predialysis values) of three different synthetic polymers (polysulfone, PSF; polyacrylonitrile-co-sodium methallyl sulfonate, AN69; ethylenevinylalcohol, EVAL) on the expression of leukocyte adhesion molecules (CD11b/CD18, CD15s) and the interactions between leukocytes and platelets under conditions of routine clinical use. For neutrophils, a statistically significant difference was found in CD15s expression for EVAL as compared to AN69 (p<0.05) and in CD11b/CD18 expression for PSF as compared to both EVAL (p<0.01) and AN69 (p<0.05). No difference between membranes was found on the expression of such adhesive molecules on monocytes. Significant differences in platelet-neutrophil (but not in platelet-monocyte) coaggregate formation were observed between PSF and both EVAL (p<0.001) and AN69 (p<0.01). Reactive oxygen species production by neutrophil population during hemodialysis was significantly different between each pair of synthetic polymers (PSF vs EVAL, p<0.001; PSF vs AN69, p<0.001; AN69 vs EVAL, p<0.05). Our data demonstrate that in terms of leukocyte adhesion receptors and platelet-leukocyte interactions, the biocompatibility profile of the synthetic membranes polysulphone, AN69 and EVAL shows many similarities but also several significant differences. Our results support the concept that biocompatibility evaluation of each membrane should be based exclusively on data generated by that membrane in order to avoid errors based on assumptions about group characteristics.

Endoscopy as a tool for diagnosing and treating gastrointestinal angiodysplasia in haemodialysis patients

Gastroenteric angiodysplasia is an important cause of haemorrhage in chronic renal failure patients. This paper reports on 2 patients on maintenance haemodialysis with upper gastrointestinal bleeding due to different manifestations of angiodysplasic lesions (sudden appearance of haematemesis and melaena in one case, progressive anaemia with apparent resistance to erythropoietin in the other case). Exploratory endoscope examination of the first digestive tract showed in both cases the presence of bleeding angiodysplasic lesions. Both patients were there and then submitted to surgical endoscopy, during which the bleeding angiodysplasic lesion was sclerosed with physiological salt solution plus adrenaline 1/10000 and 1% polydocanol. In one patient, bleeding occurred again ten days later, making renewed surgical endoscopy necessary. In the course of this an elastic ligature was made to the superangular angiodysplasia. A year later in both cases there were no direct or indirect signs of further bleeding; an endoscopic check-up showed the treated lesions to be sclerosed. Endoscopy offers the unique possibility of being used for both diagnostic and therapeutic purposes in a single session. In expert hands, endoscope therapy is effective and markedly reduces the risk of side effects.

[Possibilities of CT typing of liposarcomas]

Twenty-nine cases of liposarcomas were examined by CT; in 60% of them the CT finding was that of an ill defined, often large mass with content uniformly dishomogeneous and CT numbers ranging from -40 to +28 H.U. Diagnosis of liposarcoma is often possible when this finding is recognized in a mass of the thigh or retroperitoneum where these tumors frequently arise. Authors report differential diagnosis between liposarcomas and other lipomatous tumors such as angiomyolipoma of the kidney (when it is large and only attached to the kidney by an inconspicuous pedicle) and intramuscular lipomas (50% of them are located in the thigh).

[Changes in adenosinetriphosphatase activity in rat liver after CC14 poisoning]

Our study shows evidences that CCl4 administration (at the dose of 2,5 ml/kg b.w. "per os") increased ATPase activities in rat liver plasmamembranes 1 and 2 hours after treatment. Conversely we found that CCl4 poisoning decreased ATPase activities in microsomal membranes of rat liver at the same tested times. Therefore we suggest that ATPase activities were differently influenced by CCl4 treatment with respect to different subcellular distribution of those enzymes.

[Changes in the adenosinetriphosphatase activity in plasma membranes incubated in vitro in the presence of 4-hydroxy-2,3-nonenal]

Cation-dependent ATPase activities of rat liver plasmamembranes incubated "in vitro" with 4-hidroxy-2,3-nonenal (HNE, an aldehyde from peroxidative decomposition of biological membrane lipid moieties) are investigated. Mg++-ATPase activity is inhibited significantly by all the doses of HNE used (13,9, 4,1,1,2, 0,35 and 0,10 microM). Evidences for the inhibition of Mg++- Na+- K+- ATPase activity are also presented. Ca++- ATPase activity is strongly increased when rat liver plasmamembranes are incubated in presence of HNE 13,9 microM. Our results suggest that HNE may play a role in the control of intracellular cation levels acting directly on mechanisms of plasmamembranes ion transport.