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J Pospíchal

Publications and source records attributed to J Pospíchal.

At least 19 recordsLinked to original sources
PubMed2001

Analytical aspects of carrier ampholyte-free isoelectric focusing.

The applicability of carrier ampholyte-free isoelectric focusing (CAF-IEF) for analyses of ampholytes is demonstrated. The suggested method is based on the principle of both side regulated ionic matrix in CAF-IEF. A sharp step of pH is created in the column filled with a sample dissolved in a background electrolyte by influence of current and solvolytic fluxes. Here, ampholytes are focused upon. The magnitude of the step, its velocity and direction of its movement can be regulated electrically. In this manner, favorable separation properties of the system can be set up, even during the run. This brings several advantages over conventional methods. The principles of the separation can be easily changed, permitting selective pre-concentration (trapping) of minor components by processing large amounts of a sample to be preformed, effective isotachophoresis or IEF pre-separation and final electrophoretic analysis in one run. Advantages of these combinations are discussed together with the right choice of the working electrolyte. A 1000-fold increase in amount of substance in a column can be achieved for both isotachophoresis and capillary zone electrophoresis combined with CAF-IEF pre-concentration at reasonable working conditions. It enables a limit of detection at the nmol/l level with a concentration factor of about 10(7) to be reached.

Electrolytes↗
PubMed1994

Electrically controlled focusing of proteins and ampholytes between two modified electrolytes. Computer simulation.

Properties of the focusing in simple electrolyte systems using four-pole electrophoretic capillary column was evaluated by a computer simulation. Simulated concentration, pH and conductivity profiles confirm the previous experimentally observed features of the technique, i.e., high concentration capabilities, separation of the ampholytes and proteins into individual adjacent zones, sharp profile of zones and presence of only background electrolyte in the zone. Moreover, the influence of the magnitude of the solvolytic fluxes on the position of the zones in the column is demonstrated.

Buffers↗
PubMed1989

Step change of counterion--a new option in capillary zone electrophoresis.

In contrast to common capillary zone electrophoresis, with a constant composition of the background electrolyte, a new method is described, based on a change of the ionic matrix composition during the migration of the sample components. The proposed method expands the scale of pK's of analyzed compounds in a single run and affords new potential for optimizing the separation. The step change of the ionic matrix composition was achieved by displacing the primary matrix by the modified ionic matrix (electrolyte) which migrated against the movement of the sample components. The separation thus proceeded in the primary ionic matrix (electrolyte) while the detection was performed in the modified matrix with resultant shortening of the analysis time and convenient quantitation. A model mixture of five compounds, with a difference of four units in pK could be well resolved.

Dinitrophenols↗
PubMed1989

The application of plasma tartrate-resistant acid phosphatase to assess changes in bone resorption in response to artificial menopause and its treatment with estrogen or norethisterone.

Plasma tartrate-resistant acid phosphatase (TR ACP), urinary hydroxyproline excretion (UH), serum osteocalcin, and bone alkaline phosphatase isozyme were determined in a prospective study in 31 women who had undergone bilateral ovariectomy (OOX). Nine patients were followed up for 1 year without treatment and for the following 3 years when on mestranol (M) substitution. On the basis of UH, 22 patients were identified as having increased bone resorption (BR) within 3 months of OOX. Subsequently, 11 patients were treated with transdermal estradiol (E2) and 11 patients with norethisterone (norethindrone, NE). In untreated patients, the biochemical indices of BR peaked 3-6 months following OOX and biochemical indices of bone formation (BF) continued to increase from 3 until 12 months. The substitution with both E2 or M resulted in normalization in serum and urinary calcium, serum phosphate, renal threshold phosphate concentration (TmPO4/GRF), and biochemical indices of BR within 4 months of treatment. Biochemical indices of BF normalized within 6 months of treatment. In the M-treated group, these effects continued for 3 years of the follow-up. The hormonal substitution had a protective effect on cortical and lumbar spine bone mass. A significant decrease, but not to normal values, in biochemical indices of BR and a persistent elevation in indices of BF were found in NE-treated patients. Unlike E2, NE does not depress osteoblastic function. There is strong evidence supporting the utility of measurements of TR ACP in plasma in examination of women who had ovariectomies and in assessement of the efficacy of treatment.

Acid Phosphatase↗
PubMed1989

Prospective trial of ossein-hydroxyapatite compound in surgically induced postmenopausal women.

Women with increased bone resorption induced by bilateral oophorectomy 1-5 years previously (of a total of 48 women in the study, 20 were controls, and 28 were the treatment group) were studied during a 3 year follow-up. The ossein-hydroxyapatite compound (OHC) treatment provided 1.6 g calcium, 0.74 g phosphorus and 1.94 g noncollagen peptides a day. Biochemical indices of bone remodeling (urinary hydroxyproline/creatinine and calcium/creatinine ratios, bone alkaline phosphatase isoenzyme in serum and plasma tartrate resistant acid phosphatase) decreased significantly in both treatment and control groups compared with their baseline values. Biochemical indices were significantly lower in the treatment group compared to the controls after the first year, but in only half the patients after three years. By the third year these responders had significantly higher cortical area than controls. In an additional 13 women a transient response to OHC was followed by an accelerated bone loss and a return to the control values of the biochemical indices of bone resorption. In the poor responders an estrogen/progesterone substitution resulted within 6 months in a complete normalization in the biochemical parameters and in no further cortical bone loss. The results confirm a heterogeneous pattern of bone mass loss in menopause and indicate that OHC treatment is of value in preventing cortical bone loss in a portion of at-risk postmenopausal women, provided that the efficacy of the treatment is monitored.

Alkaline Phosphatase↗
PubMed1989

[Transdermal estradiol in the prevention of the menopause-induced increase in osteoresorption].

In the introduction of the paper the authors explain that it is essential to adopt effective preventive provisions to prevent the loss of osseous tissue in women after the menopause and to prevent osteoporotic fractures. In Bohemia and Moravia during the last 20 years the incidence of these frequently fatal or invalidating fractures of the proximal femur has increased substantially and in view of the ageing of the population it may be assumed that this trend will proceed further. Among possible preventive provisions, in order to eliminate undesirable metabolic side-effects of long-term hormonal substitution treatment, it seems best to administer by the parenteral route natural oestradiol by using the transdermal therapeutic Estraderm TTS system. Its effectiveness in suppressing menopause-induced enhanced bone resorption was tested in 11 women where on average within three months after bilateral ovariectomy increased bone resorption was found. In all women in the course of four months treatment all biochemical indicators of bone remodelling became normal - urinary excretion of hydroxyproline, acid plasma phosphatase activity, serum alkaline phosphatase isoenzyme, and serum osteocalcin. The dynamics of indicators of osteoresorption were similar as in women treated with oral synthetic oestrogen, which may produce, however, serious metabolic side-effects. Substitution treatment with Estraderm improves significantly also other manifestations of the climacteric oestrogen deficiency syndrome. Its safety is further enhanced by combination with progesterone.

Administration, Cutaneous↗
PubMed1987

Bone loss and biochemical indices of bone remodeling in surgically induced postmenopausal women.

In a cross-sectional study in 214 women who had undergone bilateral oophorectomy up to 12 years previously, the maximal rate of bone loss, as judged by radiogrammetry of the metacarpals and by dual-photon absorptiometry of the lumbar spine, coincided with the peak of the dissociation between urinary hydroxyproline excretion and/or plasma tartrate resistant acid phosphatase activity and the activity of bone isoenzyme of serum alkaline phosphatase. A significant negative correlation was found between the prevalence of the biochemical indices of bone resorption relative to bone formation and/or biochemical indices of bone resorption and the change in the metacarpal cortical area per year. The prevalence of bone resorption relative to bone formation was evident even 12 years after oophorectomy, indicating continuous imbalance of bone remodeling in the patients. Accordingly, the rates of 2.8% cortical and 8% trabecular bone loss per year on the first year after oophorectomy decreased exponentially but did not become asymptotic with the slow phase of bone loss in healthy women up to 12 years after oophorectomy.

Acid Phosphatase↗
PubMed1980

Vascular surgery in the treatment of impotence; its present possibilities and prospects.

Five years ago we reported on a technique of direct arterial anastomosis with the cavernous bodies of the penis. At that time we expressed the hypothesis that in some cases impotence could be the result of organic changes in the arterial bed supplying the cavernous bodies. A histological study was therefore performed on postmortem material and a new arteriographic technique - phalloarteriography - was developed to visualize the internal pudendal artery, the penile artery and its branches. Bilateral examination carried out in 132 patients with erectile impotence established stenosis or occlusion of these arteries or aplasia of the deep penile artery in most of them. Stenoses or occlusions were either of traumatic (after pelvic fracture) or sclerotic origin in middle aged and older patients or were related to diabetes. In more than 20% of patients with occlusions in the arterial bed plastic induration of the penis (Peyronie's disease) was found. Phalloarteriography has become the basic technique of surgical indication and approach. Revascularization procedures consisted of anastomosis of the inferior epigastric artery to the dorsal penile artery or directly to the cavernous bodies. The results attained in the first 54 patients confirmed the vasculogenic origin of their impotence. The development of phalloarteriography and revascularization procedures contribute to surgical management of impotence and extend the use of vascular surgery.

Adult↗