Fatty acyl moieties: improving Pro-rich peptide uptake inside HeLa cells.

In the field of drug delivery there has been a continuous study of powerful delivery systems to aid non permeable drugs in reaching their intracellular target. Among the systems explored are cell penetrating peptides (CPPs), which first garnered interest a decade ago when the interesting translocation properties of the pioneer CPPs Tat and Antp were described. A new family of CPPs has recently been described as non cytotoxic Pro-rich vectors with favorable profiles for internalization in HeLa cells. Fatty acyl moieties that can tune a peptide's interaction with the lipophilic environment of a cell membrane have been incorporated into the Pro-rich sequence. Improvements in cellular uptake of peptides modified with fatty acyl groups, as studied by confocal microscopy and flow cytometry, as well as the results obtained by the interaction of these peptides with a model dioleoylphosphatidylcholine (DOPC) membrane and transmission electron microscopy (TEM), illustrate the importance of the fatty acyl moieties for efficient internalization.

Gordon's syndrome: increased maximal rate of the Na-K-Cl cotransport and erythrocyte membrane replacement of sphingomyelin by phosphatidylethanolamine.

OBJECTIVE: Gordon's syndrome comprises hypertension, hyperchloremic acidemia, hyperkalemia and intact renal function. We hypothesize that disturbances of one or more cell membrane ion carriers, handling sodium, chloride and potassium, might be relevant in this disorder and, furthermore, that such disturbances might be related to altered.cell membrane composition. DESIGN AND METHODS: In a patient diagnosed with Gordon's syndrome, we assessed the kinetics (K(m) and maximal rate) of four membrane sodium transport systems in sodium-enriched erythrocytes, according to the technique of Garay. We also measured the lipid composition of erythrocyte membrane in this patient and 69 essential hypertensive controls, using the latroscan technique. RESULTS: Compared to reference values of patients with essential hypertension, this patient exhibited a marked increase in the maximal rate of the Na+-K+-2Cl(-)-cotransport (964.0 micromol/l per cell versus the 391.6 +/- 222 micromol/l per cell in essential hypertensives). Also, there was an increased concentration of erythrocyte membrane phosphatidylethanolamine and a reduced concentration of sphingomyelin (27.9 and 11.1% versus 17.9 +/- 3.8% and 18.2 +/- 3.4%, respectively). CONCLUSIONS: We conclude that this abnormality in membrane Na+-K+-2Cl- cotransport could be responsible for the hyperkalemia, hyperchloremic acidemia and increased reabsorption of sodium observed in this condition and, furthermore, that such disturbance in membrane cotransport might be related to altered phospholipid concentration in cell membranes.

[Decreased activity of 11-beta-hydroxysteroid dehydrogenase in patients with Cushing's syndrome]. / Disminución de la actividad de la 11-beta-hidroxiesteroide deshidrogenasa en pacientes con síndrome de Cushing.

BACKGROUND: To study 11 beta-hydroxysteroid dehydrogenase activity in Cushing's syndrome. PATIENTS AND METHOD: Measurements of free cortisol, cortisone, tetrahydrocortisol and tetrahydrocortisone in 24 h urine samples of patients with Cushing's syndrome and controls. RESULTS: The cortisol to cortisone and tetrahydrocortisol to tetrahydrocortisone relationship was significant (in controls, r = 0.70; p < 0.0001, and r = 0.75; p < 0.0001) respectively, but it was not in patients with Cushing's syndrome. CONCLUSIONS: 11 beta-hydroxysteroid dehydrogenase activity is decreased in patients with Cushing's syndrome.

[Blood flow in patients with intracerebral hemorrhage. Does there exist the associated hypoperfusion? A transcranial Doppler study]. / Flujo sanguíneo en la hemorragia cerebral. Hay hipoperfusión asociada? Un estudio con Doppler transcraneal.

OBJECTIVE: To evaluate, using transcranial Doppler, changes in parameters in patients with cerebral hematoma, as compared with controls, for detection of possible regional hypoperfusion. PATIENTS AND METHODS: We studied 24 patients with cerebral hematomas and 15 healthy volunteers. The volume of the hematoma and the hypodense area was determined by computerized axial tomography of the skull at the time of admission. The average speed and index of pulsation of the anterior, middle and posterior cerebral arteries were measured in both hemispheres using transcranial Doppler within the first 100 hours. The differences between the averages were analysed using the ANOVA test and the correlations with Pearson's coefficient of correlation. RESULTS: The average speeds, except in the anterior cerebral artery, were lower in both hemispheres in the patients than in the controls (p < 0.001). There were interhemispherical differences in the average speeds in the patients (p = 0.06). The indices of pulsatility were greater in both hemispheres in the patients than in the controls (p < 0.001). These differences were independent of age, sex and arterial blood pressure. The average speed in the ipsilateral middle cerebral artery showed excellent correlation with the size of the hypodense area (r = -0.92) and the hematoma (r = -0.89). The indices of pulsatility showed little correlation with the size of the lesion. There was moderate correlation between transcranial Doppler and clinical scales. CONCLUSION: Transcranial Doppler detects cerebral hypoperfusion in patients with hematoma. The excellent correlation of the average speed in the middle cerebral artery with the size of the lesion and the low correlation of the indices of pulsatility, which did not show interhemispherical asymmetry, suggest that the mechanisms of hipoperfusion are different from the intracranial hypertension.

[Essential mixed cryoglobulinemia as a cause of ischemic cerebrovascular accident]. / Crioglobulinemia mixta esencial como causa de accidente cerebrovascular isquémico.

INTRODUCTION: Involvement of the central nervous system in patients with essential mixed cryoglobulinaemia is rare, and there are few cases described in the medical literature. Moreover, the mechanism by which lesions are produced in the central nervous system is still not clear. CLINICAL CASE: We describe the case of a 35 year old woman who presented with dysarthria, weakness and paraesthesia of her left limbs and left central facial paralysis of sudden onset. Vascular studies showed the presence of IgG-IgM polyclonal positive cryoglobulins and polymerase chain reaction (PCR) showed hepatitis C virus to be present. Cerebral magnetic resonance showed ischemic lesions in the tail of the right caudate nucleus and right corona radiata and the posteromedial part of the right putamen. Other investigations were negative or normal. CONCLUSIONS: In young patients with cerebral vascular pathology the possibility of hepatitis C and essential mixed cryoglobulinemia should be considered, especially when the transaminases are raised as in our patient. We consider that the physiopathological mechanisms must be related to factors which determine a prothrombotic state in the arterial bed involved.

[Transient global amnesia and vascular risk factors]. / Amnesia global transitoria y factores de riesgo vascular.

INTRODUCTION: Transient global amnesia (TGA) is a clinical syndrome determined by an episode of less than 24 hours consisting of temporo-spatial disorientation with retrograde and anterograde amnesia followed by complete recovery. OBJECTIVES: To determine whether the presence or absence of vascular risk factors (VRF) in patients with TGA is associated with different clinical data and/or examination findings. PATIENTS AND METHODS: A retrospective study was made of two groups of 13 and 12 patients with TGA, who presented with and without VRF, respectively. The following variables were determined: VRF, age, a previous history of migraine, triggering factors, duration and repetition of the episodes, associated neurological symptoms and findings obtained by neuroimaging, eco-Doppler of the supra-aortic trunks and transcranial Doppler. The data were subjected to statistical analysis by univariate analysis with Fischer's exact probability test. RESULTS: The statistical studies showed no significant differences between the variables obtained in the two groups of patients. CONCLUSIONS: Transient global amnesia has been particularly related to migraine, epilepsy and cerebral vascular pathology, although its aetiology has not been fully determined. In this study we compare clinical data between the two groups of patients with and without VRF who have had TGA. The lack of significant differences between them tends to rule out a vascular aetiology as the sole cause of this syndrome. Recently Leao's propagated depression has been suggested as the physiopathological mechanism involved. According to this theory, the vascular pathology might act as the trigger but probably not as the aetiological factor. The findings of our study may support this thesis.

Surface grafting onto template-assembled synthetic protein scaffolds in molecular recognition.

Creating functional biological molecules de novo requires a detailed understanding of the intimate relationship between primary sequence, folding mechanism, and packing topology, and remains up to now a most challenging goal in protein design and mimicry. As a consequence, the use of well-defined robust macromolecules as scaffolds for the introduction of function by grafting surface residues has become a major objective in protein engineering and de novo design. In this article, the concept of scaffolds is demonstrated on some selected examples, illustrating that novel types of functional molecules can be generated. Reengineered proteins and, most notably, de novo designed peptide scaffolds exhibiting molecular function, are ideal tools for structure-function studies and as leads in drug design.

[The stroke chain: from the onset of symptoms to the emergency services]. / La cadena del ictus: desde el inicio de los síntomas a los Servicios de Urgencias.

INTRODUCTION: The treatment of stroke by thrombolysis or other methods (neuroprotection, basic care, etc.) is more effective the sooner it is begun. The main reasons for patients not receiving treatment during the acute phase of their illness are slowness in reaching hospital and delay in emergency assessment once they arrive there. It is necessary to identify the factors involved in these delays so as to modify what can be improved and establish guidelines. DEVELOPMENT: In the chain of events leading to arrival in hospital there are independent factors related to the social and health characteristics of the patients, their attitudes to illness, characteristics of the stroke itself and of the health district. Analysis of the system for response to stroke patients is extremely important before investing in measures to be applied during the acute phase. This analysis should be based on the different stages at which delays may occur. Outside the hospital, the systems to be recognized are those of the patient and his family, contact with prehospital care teams and transport to the hospital of reference. Hospital care involves making contact on arrival at the Emergency Department, and the response of the neurologist or stroke team who give the initial treatment. CONCLUSIONS: Programmes of education and improvement in the organization of the different protagonists at the various stages reduce the time lost by delay.

Sodium transport kinetics, cell membrane lipid composition, neural conduction and metabolic control in type 1 diabetic patients. Changes after a low-dose n-3 fatty acid dietary intervention.

BACKGROUND: A decreased content of n-3 fatty acids in erythrocyte membrane of type 1 diabetic patients, which is inversely related to plasma levels of HbA(1c), has been reported previously. Our aim in this study was to observe the changes after a low-dose n-3 fatty acid (330 mg/day docosahexaenoic acid and 630 mg/day eicosapentanoic acid) dietary intervention in the lipid composition of cell membrane and metabolic control (measured according to plasma HbA(1c) levels). Since changes in both parameters may alter transmembrane sodium transport or influence parameters measuring target organ damage, we also studied the neural conduction quality and activity of four sodium transporters. METHODS: Eighteen type 1 diabetic patients were randomly assigned to continue their usual diet (control group) or to supplement their diet with a daily low dose of n-3 fatty acids (supplemented group). The changes between baseline and end values of the following parameters were compared: HbA(1c), lipid and phospholipid composition of cell membrane, activity of four ion carriers and neural conduction quality. RESULTS: The dietary supplementation caused statistically significant changes in membrane lipid composition, particularly an increase of C22:6 (n-3) and the total n-3 fatty acid (respectively +0.90+/-1.14% vs. -0.44+/-1.23% and +1.36+/-1.62% vs. -0.5+/-1.80%, p<0.05). After the dietary supplementation, we also observed a significant decrease of HbA(1c) (-2.00+/-1.9% vs. -0.13+/-0.48%, p<0.05), without significant changes in the dose of insulin required, an increase in the motor conduction velocity by the median nerve (+2.12 +/-1.35 m/s vs. -0.8+/-2.34 m/s, p<0.05) and a decrease of the V(max) of the Na(+)-Li(+) countertransport (-96.6+/-111.2 vs. +58.1+/-81.3 micromol/l cell/h(-1), p<0.01). CONCLUSION: A low-dose omega-3 fatty acid dietary supplementation may change the fatty acid composition of the cell membrane and improve the metabolic control of diabetes. Using this dose, we also observed a decrease of the maximal rate of Na(+)-Li(+) countertransport and a slight improvement of neural conduction.

[Hypertensive subpopulations as defined by their natriuretic response to ambulation]. / Subpoblaciones de hipertensos definidas por la respuesta natriurética a la deambulación.

BACKGROUND: The heterogeneity among patients with essential hypertension is known. We observed in an earlier study a large spread in the values of fractional excretion of sodium in a group of subjects with mild essential hypertension after ambulation, suggesting possible subgroups among them. We defined as the retainer (R) group that which presented a reabsorption index (RI = fractional excretion of sodium during supine/fractional excretion of sodium after ambulation) < 2.5 and the non-retainer (NR) group as that whose RI < 2.5. We analyzed at what level the reabsorption of Na was produced and the differences between the possible groups. PATIENTS AND METHODS: We studied 51 mild essential hypertensive patients, 22 men and 29 women, in two consecutive periods -recumbent, 90 minutes; ambulation, 90 minutes-. We calculated the clearance of creatinine and lithium, fractional proximal and distal reabsorption of Na, plasma renin activity (PRA), plasma aldosterone (ALDO) and elimination of PGE2 and kallikrein in the urine; the plasma catecholamines at the end of the recumbent position and after 10 minutes in the upright position. The study was taken after at least ten days without treatment and following a diet with free Na intake. RESULTS: We did not encounter significant differences between the retainer (n = 19) and non-retainer (32) group with regard to age, sex, body mass index or elimination of Na/24 h. The lower natriuresis in ambulation in the R group compared with the NR group is due to a higher fractional reabsorption of sodium, proximal (83.7 +/- 4.9% vs 79 +/- 5.2; p < 0.01) as well as distal (96.8 +/- 2 vs 95.3 +/- 2%; p < 0.05). The increment in the PRA was greater in the R group (1.3 +/- 1.4 vs 0.8 +/- 0.8; p < 0.05) after ambulation; in the R group showed a lower index -increment in ALDO/increment in PRA- in response to postural change although without significancy. We observed a lower elimination of PGE2 and kallikrein in the R group as compared with NR group (p < 0.05). We did not find differences with regard to plasma catecholamines. CONCLUSIONS: Ambulation allows to distinguish two groups of essential hypertensive patients according to natriuresis. The lower natriuresis in ambulation on the part of the R group could be due to the increase in PRA and therefore of the angiotensin II at the level of the proximal tubule, and to a lower activity of natriuretic hormones (PGE21 kallikrein) at the distal level.

Erythrocyte Na(+)-Li+ countertransport in essential hypertension: correlation with membrane lipids levels.

OBJECTIVE: To examine whether Na(+)-Li+ countertransport (SLC) activity is linked to erythrocyte membrane lipid content. DESIGN: An observational case-control study. The maximal efflux rate of SLC, plasma cholesterol, triglycerides, phospholipids, low- and high-density lipoprotein cholesterol levels and the erythrocyte membrane cholesterol, phospholipids and fatty acids contents were determined both in fasting normolipaemic normotensive subjects and in hypertensive patients. METHODS: The Li(+)-stimulated Na+ efflux was measured in Li(+)-preloaded erythrocytes. Membrane cholesterol and phospholipids levels were determined by the latroscan technique. Membrane fatty acids were identificated by gas chromatography. Several derived indices were also obtained. RESULTS: Erythrocyte membranes of hypertensive patients showed an increase in cholesterol: phospholipid ratio and a decrease in the total amount of polyunsaturated fatty acids, mainly at the expense of arachidonic acid and docosatetraenoic acid. SLC activity was higher in hypertensive patients and correlated positively with the plasma triglycerides level and negatively with the ratio of C20:4 to C20:3. CONCLUSION: Our data from untreated normolipaemic hypertensive patients show that a higher SLC activity was accompanied by parameters that indicate a lower membrane fluidity.

Description of a new quotient that may differentiate blood pressure profiles in essential versus Cushing's syndrome-related hypertension.

Since the presence or absence of a nocturnal decrease in blood pressure values (BP) may suggest an increased risk of visceral complications or the existence of secondary hypertension, several methods have been described for evaluating the BP profile. Nevertheless, a universally accepted system to evaluate this item has not yet been established. Our aim in this study was to test different dispersion quotients (DQ) which estimate the differences between the mean of each hour, and the mean of all the readings in the 24 h period. These quotients may be employed regarding systolic (SBP) or diastolic (DBP) blood pressure, and may be referred to the whole period of 24 h, or to the subperiods morning (m), afternoon (a) or night (n). We have studied two non selected groups of essential (n = 20) or secondary (Cushing's syndrome, n = 17) hypertensives. We observed a marked decrease in these quotients, particularly DQ-SBP and nDQ-SBP, in secondary hypertensives (respectively 10.2 +/- 2.9 vs 15.6 +/- 4.2 and 11.8 +/- 5.0 vs 20.5 +/- 6.3, p < 0.0001), thus indicating, a blunted nocturnal fall of BP in these patients. Also the DQ and particularly DQ-SBP, nDQ-SBP and nDQ-DBP, showed a high positive and negative predictive value, sensitivity and specificity for pertaining to the Cushing's syndrome group (respectively: 0.75, 0.88, 0.88, 0.75; 0.86, 0.82, 0.77 0.90; and 0.78, 0.84, 0.82, 0.80).

Influencia de la hiperinsulinemia en el perfil lipídico de los pacientes hipertensos / The influence of hyperinsulinemia in the lipid profile of hypertensive patients

Fundamentos: la hipertensión arterial y dislipidemia se asocian con una frecuencia superior a la atribuible al azar. El aumento de resistencia insulínica/hiperinsulinemia ha sido uno de los factores implicados en la patogenia de dicha asociación. En el presente trabajo se analiza el perfil lipídico de los pacientes hipertensos según el grado de insulinemia. Métodos: se determinó el perfil lipídico (colesterol total, sus fracciones unidas a las lipoproteínas de baja densidad -cLDL-, alta densidad -cHDL-, triglicéridos y apolipoproteínas A1 y B plasmáticas), en 87 pacientes. Además, se les administró una sobrecarga oral de 75g de glucosa con determinaciones de glucemia, insulinemia y péptido C a los 0, 60 y 120 minutos. Resultados: al separar los hipertensos en 2 grupos según la insulinemia alcanzada después de la sobrecarga oral de glucosa, aquellos hipertensos con mayor grado de insulinemia tenían un aumento significativo de triglicéridos (p<0,05) disminución también significativa del cHDL (p<0,001). Los hipertensos con menor insulinemia tenían un aumento significativo del colesterol total (p<0,05) y de su fracción unida a las LDL, aunque este último no fue significativo. Conclusiones: en los pacientes hipertensos se pueden observar dos perfiles lipídicos: uno ligado a la hiperinsulinemia y caracterizado por aumento de triglicéridos y disminución del cHDL y otro sin relación con la hiperinsulinemia, que se manifestaría por aumento del colesterol total y del colesterol transportado por las LDL

[Influences of hyperinsulinemia in the lipid profile of hypertensive patients]. / Influencias de la hiperinsulinemia en el perfil lipídico de los pacientes hipertensos.

BACKGROUND: Hypertension and dyslipemia are associated with a greater frequency than that randomly expected. The increase in insulinic resistance hyperinsulinemia is one of the factors implicated in the pathogenesis of this association. In the present study the lipid profile of hypertensive patients is analyzed according to the degree of insulinemia. METHODS: The lipid profile (total cholesterol, fraction linked to low density lipoproteins cLDL, high density cHDL, triglycerides and plasma apolipoproteins A1 and B were determined in 87 patients with essential high blood pressure. Moreover an oral overdose of 75 g of glucose was administered with determinations of glycemia, insulinemia and C peptide at the time of glucose administration, 60 and 120 minutes. RESULTS: Upon separation of the hypertense patients into two groups according to the insulinemia achieved following an oral overload of glucose, those hypertensives with a greater degree of insulinemia showed a significant increase in triglycerides (p < 0.05) and also a significant decrease in cHDL (p < 0.001). The hypertensive patients with lower insulinemia showed a significant increase in total cholesterol (p < 0.05) and fraction linked to LDL although the latter was not significant. CONCLUSIONS: Two different lipid profiles may be observed in hypertensive patients: one linked to hyperinsulinemia and characterized by an increase in triglycerides and a decrease in cHDL and another with no relation with hyperinsulinemia which is manifested by an increase in total cholesterol and cholesterol transported by the LDL.

Ambulatory blood pressure monitoring in physicians working in a hospital: is there an increase in the number of subjects with high workplace blood pressures?

Sixty-two physicians from our hospital who were normotensives, as supported by casual blood pressure measurements, underwent 24-h blood pressure monitoring which included their normal work, home rest and sleep periods. During working hours, 19% of the subjects showed mean diastolic and/or diastolic plus systolic blood pressures higher than those admitted as normal by the WHO for casual measurements for out of work subjects. Both mean systolic and diastolic blood pressure measurements, during the work at the hospital, were significantly higher in males (P < 0.01 and P < 0.005, respectively) than the mean of the readings obtained during the 24-h period, but this phenomenon did not occur among the females. Male's mean systolic (129.8 +/- 10.6 vs. 117.1 +/- 9.7 mmHg, P < 0.0001) and diastolic pressures (83.4 +/- 8 vs. 74.9 +/- 7.3 mmHg, P < 0.001) were significantly higher during the working period in relation to those of the female group. Discussing the influence of the kind of work on blood pressure, we came to the conclusion of the existence in our environment of a group of subjects (generally males), presenting high blood pressure values during their working period at the hospital and normal or borderline values during the rest of the day. This should be of interest, since it has been reported that subjects with high workplace blood pressure have an increased risk of hypertension and target-organ damage.

Cell membrane fatty acid composition in type 1 (insulin-dependent) diabetic patients: relationship with sodium transport abnormalities and metabolic control.

We have studied the fatty acid composition of erythrocyte membrane phospholipids in nine Type 1 (insulin-dependent) diabetic patients and nine healthy control subjects. Cell membranes from the diabetic patients showed a marked decrease in the total amount of polyunsaturated fatty acids (19.0% +/- 2.2 vs 24.6% +/- 1.4, p < 0.0001) mainly at the expense of docosahexaenoic acid C22:6(n3) (2.9% +/- 1.1 vs 5.3% +/- 1.3, p < 0.001), and arachidonic acid C20:4n6 (12.0% +/- 1.6 vs 15.1% +/- 0.6, p < 0.0005). Conversely, the total amount of saturated fatty acids was significantly increased (p < 0.05) and the polyunsaturated/saturated ratio was decreased in the Type 1 diabetic patients (p < 0.00 005). Neither the time from diagnosis, nor C-peptide levels, correlated with parameters indicating a poor metabolic control of Type 1 diabetes. However, C22:6(n-3) and total n-3 content significantly correlated with HbA1c (r = -0.79 and r = -0.88, respectively, p < 0.01), fructosamine (r = -0.71 and r = -0.74, respectively, p < 0.05), and Na+-K+ ATPase activity (maximal rate/Km quotient) (r = 0.78 and r = 0.71, respectively, p < 0.05). In conclusion we have found marked alterations of cell membrane lipid composition in Type 1 diabetic patients. These cell membrane abnormalities in lipid content were related to sodium transport systems and to poor metabolic control. Either diet, or the diabetic state, might be responsible for the observed cell membrane abnormalities. A dietary intervention study might differentiate the role of diet and diabetes in the reported cell membrane alterations.