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Biomedical subjects

E Cerny

Publications and source records attributed to E Cerny.

13 recordsLinked to original sources

Purification of an inositol 1,4,5-trisphosphate-binding calreticulin-containing intracellular compartment of HL-60 cells.

To investigate the identity of Ins(1,4,5)P3-sensitive intracellular Ca2+ stores in myeloid cells, we have developed a method that yields subcellular fractions highly enriched in Ins(1,4,5)P3 binding. HL-60 cells were disrupted by nitrogen cavitation, and subcellular fractions were obtained by differential centrifugation, followed by Percoll- and sucrose-density-gradient separations. A subcellular fraction enriched 26-fold in Ins(1,4,5)P3-binding sites was obtained. This fraction showed no enrichment in plasma-membrane markers and only a comparatively moderate enrichment (7-fold) in endoplasmic-reticulum markers. The ratio between specific enrichment of Ins(1,4,5)P3 binding and endoplasmic-reticulum markers in the different fractions varied over 50-fold, from less than 0.1 to greater than 5. The purified Ins(1,4,5)P3-binding fraction was enriched to a similar extent (27-fold) in the putative intravesicular Ca(2+)-storage protein calreticulin. Our results favour the concept of a distinct Ins(1,4,5)P3-binding, calreticulin-containing compartment (i.e. the calciosome) in HL-60 cells.

Calcium-Binding Proteins↗

Centrifugation-augmented solid-phase immunoassay (CASPIA) for the rapid diagnosis of infectious diseases.

We have devised centrifugation-augmented solid-phase immunoassays (CASPIAs) for the detection of microbial pathogens in human body fluids. The CASPIA format combines several features of latex agglutination and solid-phase immunoassay systems to produce an assay system that is inexpensive and simple to perform. We found that CASPIA systems for the detection of rotaviral, group A streptococcal, and Haemophilus influenzae type b antigens were significantly more sensitive than latex agglutination assays and at least as sensitive as enzyme immunoassay systems using analogous reagents. Because CASPIA reactions could either be read macroscopically, recorded with a standard office photocopying device, or quantitated by means of a microplate colorimeter, the assays were applicable under a wide range of clinical and laboratory conditions.

Agglutination Tests↗

[Hereditary salt sensitivity as a cause of essential hypertension: studies of membrane transport and intracellular electrolytes].

Based on oscillatory long-term blood pressure recordings and on biochemical findings in 62 normotensive and 54 untreated hypertensive subjects, who were investigated during their usual high sodium diet and after moderate salt restriction, we have developed a concept for the pathogenesis of essential hypertension, which differs from current concept proposed by others: We demonstrated that normotensive subjects with a positive family history of hypertension respond to sodium restriction from 200 to 50 mmol/day over 2 weeks with a minute fall of mean blood pressure of 2.9 +/- 0.7 mmHg (+/- SEM), whereas in subjects with a negative family history of hypertension blood pressure remained unchanged (-0.93 +/- 0.67 mmHg). This difference was only revealed by computing the "basal blood pressure average" from 240 heart beats, but not by conventional sphygmomanometric blood pressure measurements. Normotensives with heredity of hypertension or "salt sensitive" normotensive subjects were not different from subjects with a negative family history in the sodium pump, Na-K-cotransport or intracellular sodium and potassium of erythrocytes. In contrast, the former group had an increased sensitivity to infused noradrenaline, which might be responsible for enhanced tubular sodium reabsorption in subjects with a positive family history of hypertension (or "salt sensitive" subjects). We only found an increased K-permeability of red cells in established hypertension, which was compensated for by a an increased activity of the sodium pump. These cell membrane defects were more pronounced in more severe hypertension. In the course of essential hypertension a cell membrane defect may develop as a consequence rather than a cause of the disease.

Adult↗

Salt sensitivity in normotensives with family history of hypertension: studies of membrane transport, intracellular electrolytes and alpha 2-adrenergic receptors.

Using long-term automatic blood pressure recording it has previously been shown that subjects with family history of hypertension show a minute fall of blood pressure during sodium restriction, which is reversible by high sodium intake. Thus normotensives with hypertensive antecedents as a group are salt-sensitive, whereas normotensives without heredity of hypertension as a group are salt-resistant. The present study compares intracellular sodium, potassium and calcium, sodium pump activity, NaK-cotransport of red blood cells and density and affinity of alpha 2-adrenergic receptors of platelets in normotensive subjects classified according to family history of hypertension and according to 'salt sensitivity' and 'salt resistance'. Neither the family history of hypertension nor salt sensitivity correlated with intracellular sodium, potassium, calcium, Na-pump activity and NaK-cotransport. Alpha 2-adrenergic density was higher in salt-sensitive than in salt-resistant subjects (P < 0.05) but similar in subjects with a positive and negative family history of hypertension. However, alpha 2-adrenergic receptor density decreased significantly during 2 weeks of moderate salt restriction from 169.6 +/- 34.2 to 142.6 +/- 30.8 (P < 0.01, paired t-test), which may explain the decreased pressor response to infused noradrenaline observed in a previous study during moderate salt restriction. It is concluded that in humans there is no association of genetic predisposition of hypertension or of salt sensitivity to an alteration of sodium pump activity, NaK-cotransport, intracellular sodium and calcium. Alpha 2-receptor density of platelets deserves further study as a possible predictor of salt sensitivity in normotensives.

Adult↗

Raised sodium pump activity and a circulating sodium transport inhibitor demonstrated on red blood cells of patients with untreated essential hypertension: correlation of pump activity with potassium permeability.

We have studied sodium potassium ATPase activity, the effect of endogenous plasma on sodium pump activity, potassium permeability and intracellular sodium and potassium concentrations in normotensive subjects without (n = 36) and with (n = 33) a positive family history of hypertension, and in patients with untreated essential hypertension (n = 52). Sodium pump activity was studied as ouabain sensitive uptake of rubidium 86 in washed red blood cells, incubated in an artificial medium closely resembling the anorganic constituents of plasma. Any influence of endogenous plasma on sodium pump activity was investigated by re-incubating the washed red blood cells in their own plasma and comparing ouabain sensitive rubidium uptake in the two media. To correct for any possible differences in external potassium concentration, a function for the relation between extracellular potassium concentration and absolute transport rates was derived experimentally. From this, actual transport rates in plasma were corrected by computer to an extracellular potassium concentration of 4.0 mmol/l. Sodium pump activity, concentration of circulating sodium transport inhibitor, potassium permeability and intracellular electrolytes were not statistically different in subjects with and without a positive family history of hypertension. Hypertensives had significantly raised sodium pump activity in artificial medium, but not when red cells were re-incubated in their own plasma. Thus, endogenous plasma inhibited the sodium pump by between 12% and 15%. Hypertensives also had a significantly raised potassium permeability. Potassium permeability and sodium pump activity were correlated significantly. Intracellular sodium concentrations were similar in normotensives and hypertensives, but the later showed a significantly lower intracellular potassium concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Salt sensitivity in normotensives with and salt resistance in normotensives without heredity of hypertension.

We have studied blood pressure responses to moderate sodium restriction from 200 to 50 mmol/day over 2 weeks in 62 normotensive subjects with and without a family history of hypertension by continuous automatic blood pressure recording. Based on the average of the blood pressure of 1 hour continuous monitoring under basal conditions, we have been able to demonstrate a significant fall of blood pressure in 28 young subjects with a heredity of hypertension after moderate sodium restriction from 200 to 50 mmol over 2 weeks (fall in systolic blood pressure 5.4 +/- 1.1, diastolic 2.5 +/- 0.8, mean blood pressure 2.9 +/- 0.7 mmHg, mean +/- SEM), whereas blood pressure remained unchanged in a group of 34 subjects without heredity of hypertension after moderate sodium restriction (change in systolic blood pressure -1.0 +/- 0.6, diastolic blood pressure -0.6 +/- 0.7 and mean blood pressure -0.93 +/- 0.67 mmHg). 29 of the subjects were studied a third time 2 weeks after having returned to their usual high sodium diet and in those in whom a blood pressure fall was observed during sodium restriction it returned to pre-intervention values. This demonstrates that normotensives with a heredity of hypertension are salt sensitive and adds further evidence that a high sodium intake may be of critical importance for the initiation of essential hypertension.

Adult↗

[Nosocomial epidemic of echovirus type 7 in a neonatology department].

Epidemiology, clinical features and laboratory results of a nosocomial outbreak of Echovirus 7 infections are described. After the admission of the index case with presumably perinatal infection to the neonatology unit, 3 additional babies from the total of 16 patients on the ward were infected. A 5th baby in another unit was also infected; this baby shared in part the nursing staff with the other group. Clinical symptoms of the infection were fever (5 children), gastrointestinal (5) and neurological symptoms (4), apnea and bradycardia (1), and a fine macular rash (1). Five of the 24 persons of the staff suffered from a febrile gastroenteritis during this period. The virus was isolated from stool swabs, throat swabs, urine, blood and CFS. An augmented percentage of immature neutrophils in the peripheral blood count was the only laboratory value found to be abnormal in all of the children. We measured neutralizing antibodies against this virus in an immunoglobulin preparation for i.v. use (Sandoglobulin), to get information about its prophylactic value in these cases. We could not detect any neutralizing antibodies.

Cross Infection↗