Clinical experience with a new tooth-colored dental restorative material (Ariston pHc) on primary teeth.
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Cariostatic Agents↗
Biomedical subjects
V Weiss
Publications and source records attributed to V Weiss.
[Sleep apnea syndrome in acromegaly. Treatment and development-- retrospective analysis].
In total 56 subjects with acromegaly (37 men and 19 females) were examined in attempt to find sleep apnoea syndrome (SAS). The examination consisted of clinical examination and of all-night monitoring MESAM4 or polyMESAM. The diagnosis of SAS was established in 76.4% of subjects: 31 men and 11 females, average age 51.8 (SD +/- 9.6) years. The average ODI (oxygen desaturation index--number of oxygen saturation drops per 1 hour of sleep) of SAS patients was 29.2 (+/- 20.7). The therapy of SAS was recommended to 27 patients: sleeping position on the side (3 patients), reduction of the weight (8 patients), change of hypnotic drug (1 patient) and CPAP--continuous positive airway pressure (24 patients). CPAP titration was performed in 18 patients (in one subject the titration was repeated 4 years later). CPAP was titrated within all-night polysomnography in 10 subjects and in 9 subjects using self adjusting CPAP. Primary acceptance of CPAP was 94.4%. The average CPAP pressure was 7.8 (+/- 2.1) mbar. The theoretical duration of CPAP use was 546.6 (+/- 533.7) days. Long term compliance was considered as sufficient (weekly 25 hours or more) in 66.7% of patients. Ten patients underwent important acromegaly therapy or its change during the follow up and the improvement or the disappearance of SAS symptoms occurred in 6 of them.
Acromegaly↗
[The fluoride content in children's toothpastes].
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Child↗
[Can normalization of vascular cytoadhesive activity be explained by the anti-atherosclerosis effect of growth hormone?].
BACKGROUND: The increased mortality caused by premature atherosclerosis has been shown among patients with hypopituitarism receiving conventional hormone treatment but with unsubstituted growth hormone deficiency. This experience belongs among the most important arguments in favour of replacement with growth hormone. The mechanisms of the antiatherogenic effect of growth hormone are poorly understood. The protective effect of growth hormone on the vascular endothel and its intervention in the clotting process, which have not been yet elucidated, may be the causative factors. METHODS AND RESULTS: The endothelial damage as given by measuring of circulating soluble cytoadhesive molecules sE-selectin, sP-selectin and intercellular adhesive molecule 1 (ICAM 1) was measured in 15 adult panhypopituitaric patients before and after 1 year treatment with recombinant human growth hormone. The blood levels of all of these cytoadhesive molecules decreased significantly (p < 0.01) during the treatment. None of the concomitantly followed coagulation tests (prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin III, von Willebrand's factor and D-dimer) was significantly changed during the treatment. The tendency to decrease (p = 0.054) was observed with antithrombin III. CONCLUSIONS: The decrease of circulating cytoadhesive molecules in blood during the treatment of growth hormone gives evidence for its protective effect, either direct or mediated, on the vascular endothel. These findings could bring an explantation for the premature atherosclerotic changes in hypopituitarism and antiatherogenic effect of growth hormone.
Adult↗
DNA binding and oligomerization of NtrC studied by fluorescence anisotropy and fluorescence correlation spectroscopy.
Fluorescence anisotropy and fluorescence correlation spectroscopy measurements of rhodamine-labeled DNA oligonucleotide duplexes have been used to determine equilibrium binding constants for DNA binding of the prokaryotic transcription activator protein NtrC. Measurements were made with wild-type NtrC from Escherichia coli and the constitutively active mutant NtrCS160Ffrom Salmonella using DNA duplexes with one or two binding sites. The following results were obtained: (i) the dissociation constant K d for binding of one NtrC dimer to a single binding site was the same for the wild-type and mutant proteins within the error of measurement. (ii) The value of K d decreased from 1.4 +/- 0.7 x 10(-11) M at 15 mM K acetate to 5.8 +/- 2.6 x 10(-9) M at 600 mM K acetate. From the salt dependence of the dissociation constant we calculated that two ion pairs form upon binding of one dimeric protein to the DNA. (iii) Binding of two NtrC dimers to the DNA duplex with two binding sites occured with essentially no cooperativity. Titration curves of NtrCS160Fbinding to the same duplex demonstrated that more than two protein dimers of the mutant protein could bind to the DNA.
Amino Acid Sequence↗
[Growth hormone deficiency and its treatment in adults].
Deficiency of growth hormone produced in the pituitary is manifested not only in children by impaired growth but also in adults. It is encountered most frequently in adults after surgery or irradiation in the hypothalamo-pituitary area, less frequently in idiopathic disorders of growth hormone production and secretion, either isolated or in conjunction with other trophic pituitary hormones. The diagnosis of growth hormone deficiency must be assessed by dynamic stimulation tests: most frequently the insulin stimulation test is used. Growth hormone deficiency in adult age is manifested by various non-specific symptoms which resemble symptoms (manifestations) of ageing: increase of adipose tissue, deterioration of lipid metabolism, osteopenia, impaired cardiac output and others; the symptoms recede partly if growth hormone is administered for a prolonged period. Clinical trials which are under way should define not only suitable indications but also ways of administration of this expensive treatment.
Adult↗
To teach is to learn twice. Resident teachers learn more.
OBJECTIVES: To describe the formal teaching activities of pediatric residents and to assess how the act of formal teaching affects residents' acquisition and retention of knowledge. DESIGN AND METHODS: Randomized controlled trial. Forty-three pediatric residents in a university-based program were surveyed about their teaching activities, given a pretest on a predetermined topic (oral rehydration), then randomly assigned to either teach (n = 18) or listen to (n = 25) a 30-minute lecture on that topic; 6 to 8 weeks later they completed a posttest. The difference between [retest and posttest scores was calculated for each resident as an index of knowledge acquisition. RESULTS: The mean number of resident teaching events per year was 3.5 for interns (n = 16), 2.9 for junior residents (n = 11), and 6.9 for senior residents (n = 16). Self-reported comfort with the teaching role, ability to hold a group's attention, and desire to teach were similar across year of training. Prior to randomization, teachers (experimental group) reported less interest in oral rehydration that did listeners (control group) (P < .03). However, knowledge acquisition was significantly greater for teachers than for listeners (posttest score minus pretest score [mean +/- SD], 6.1 +/- 4.2 vs 3.2 +/- 2.5; P < .01). IMPLICATIONS: Among pediatric residents, formal teaching enhances knowledge acquisition relative to self-study and lecture attendance.
Adult↗
Local anesthesia for above knee femoropopliteal bypass: an alternative technique to endoluminal bypass grafting.
BACKGROUND: The majority of patients with peripheral vascular disease have associated medical illnesses that contribute to a substantial incidence of perioperative complications. Some of the these complications may be related to the choice of anesthetic used. An ideal anesthetic would provide good analgesia, have few complications associated with its use, including minimizing hemodynamic instability, and provide an adequate surgical environment. MATERIALS AND METHODS: Ten patients with an occluded superficial femoral artery and claudication or rest pain were selected. Eligibility criteria were a non-obese thigh and an above knee popliteal segment of at least 10 cm. Lidocaine local anesthesia with systemic sedation was employed. Above knee femoropopliteal bypasses were performed in all patients. Intraoperative fluid volume, anesthetic dose and perioperative morbidity were recorded. RESULTS: All patients tolerated the procedure well. The operating environment was excellent. Intraoperative fluid requirements were less for patients receiving local anesthesia as compared with a similar group of patients undergoing above knee femoropopliteal bypass receiving regional anesthesia (mean 1750 ml versus 3386 ml). The mean dosage of lidocaine (0.5%) was 367 mg over a mean of 116 min operating time. All patients ambulated within 8 hours. There was no perioperative morbidity, mortality or graft occlusion. CONCLUSION: This technique is easy to perform and further reduces the systemic magnitude of anesthesia, while providing excellent perioperative analgesia and a satisfactory surgical environment. It may be ideal for the high risk patient, as intraoperative fluid volume requirements are reduced. In an era where endoluminal bypass grafting is being increasingly advocated, this technique retains the benefits of bypass grafting while possibly reducing the physiological insult.
Anastomosis, Surgical↗
Specificity of the BvgAS and EvgAS phosphorelay is mediated by the C-terminal HPt domains of the sensor proteins.
Despite the presence of highly conserved signalling modules, significant cross-communication between different two-component systems has only rarely been observed. Domain swapping and the characterization of liberated signalling modules enabled us to characterize in vitro the protein domains that mediate specificity and are responsible for the high fidelity in the phosphorelay of the unorthodox Bvg and Evg two-component systems. Under equimolar conditions, significant in vitro phosphorylation of purified BvgA and EvgA proteins was only obtained by their histidine kinases, BvgS and EvgS respectively. One hybrid histidine kinase consisting of the BvgS transmitter and HPt domains and of the EvgS receiver domain (BvgS-TO-EvgS-R) was able to phosphorylate BvgA but not EvgA. In contrast, the hybrid protein consisting of the BvgS transmitter and the EvgS receiver and HPt domains (BvgS-T-EvgS-RO) was unable to phosphorylate BvgA but efficiently phosphorylated EvgA. These results demonstrate that the C-terminal HPt domains of the sensor proteins endow the unorthodox two-component systems with a high specificity for the corresponding regulator protein. In the case of the response regulators, the receiver but not the output domains contribute to the specific interaction with the histidine kinases, because a hybrid protein consisting of the EvgA receiver and the BvgA output domain could only be phosphorylated by the EvgS protein.
Bacterial Proteins↗
[Spontaneous remission of corticosteroid osteopenia after successful surgical treatment of Cushing's syndrome. A cross-sectional study].
BACKGROUND: Osteoporosis is one of the most serious consequences of Cushing's syndrome. Only a small number of longitudinal observations on bone mineral density (BMD) in patients with treated Cushing's syndrome have been reported so far. To evaluate changes in bone mass in patients with Cushing's syndrome after surgical cure of the disease, BMD was evaluated cross-sectionally. METHODS AND RESULTS: BMD (DPX-L, Lunar) was measured in the lumbar spine and femoral neck (i.e. in skeletal areas with high proportion of trabecular and cortical bone, respectively) in 72 patients after successful surgical cure of Cushing's syndrome (8 men, 34 women before menopause and 30 women after menopause who were not on hormone replacement therapy). No other drug's interfering with skeletal metabolism were used. The reference group consisted of young healthy Czech women and/or men. The mean lumbar spine and femoral neck BMD increased to normal values within 3 and 5 years after surgery, respectively. In women after menopause, however, the significant positive relationship between BMD and time after surgery was negatively influenced by time after menopause. It is likely that several other factors contributed to the increase in bone mass in the patients (cure of hypercortisolism, recovery from hypogonadism and restoration of muscle strength). CONCLUSIONS: After surgical cure of Cushing's syndrome in premenopausal women and in men, BMD rapidly and substantially increases. The recovery is negatively affected by estrogen deficiency in postmenopause.
Adenoma↗
[Disappearance of the sleep apnea syndrome in a female patient after surgery of a hypophyseal adenoma with acromegaly].
The association of the syndrome of sleep apnoea and acromegaly was described in the literature. However, so far no satisfactory explanation was given of the more frequent concomitant incidence of these diseases. The authors describe the disappearance of the sleep apnoea syndrome in a female patient after removal of an intrasellar microadenoma of the pituitary with overproduction of growth hormone.
Acromegaly↗
A common switch in activation of the response regulators NtrC and PhoB: phosphorylation induces dimerization of the receiver modules.
During signal transduction, response regulators of two-component systems are phosphorylated in a conserved receiver module. Phosphorylation induces activation of the non-conserved output domain. We fused various domains of the response regulators NtrC, PhoB or CheB to the DNA binding domain of lambda repressor. Analysis of these hybrid proteins shows that the receiver modules of NtrC and PhoB are potential dimerization domains. In the unphosphorylated proteins, the ability of the receiver modules to dimerize is masked due to inhibition by their output domains. Inhibition can be relieved in two ways: phosphorylation of the receiver module or deletion of the output domain. In contrast, the receiver module of CheB lacks this ability for dimerization. We propose a model which groups response regulators into two classes. Common to both classes is the interaction between receiver and output domain in the unphosphorylated protein. In class I (e.g. NtrC and PhoB), this interaction leads to the inhibition of the receiver module. Phosphorylation relieves inhibition, thereby inducing activation via dimerization of the receiver modules. In class II (e.g. CheB), the interaction between receiver and output domain results in inhibition of the output domain. Phosphorylation relieves inhibition, thereby activating the output domain.
Adenosine Triphosphatases↗
Mechanism of activation of a response regulator: interaction of NtrC-P dimers induces ATPase activity.
NtrC is the transcriptional activator for nitrogen-regulated promoters and, as a response regulator, belongs to the protein family of two-component systems. The activity of all response regulators is modulated by phosphorylation of the conserved N-terminal receiver domain. Phosphorylation of the dimeric NtrC has two consequences: (i) a strong increase in the cooperative binding of NtrC to two adjacent binding sites and (ii) activation of NtrC as an ATPase. Here we show that phosphorylation of NtrC is not sufficient for activation of NtrC. At low protein concentrations (50 nM), phosphorylated NtrC was only active as an ATPase upon cooperative binding to DNA. At high protein concentrations (above 50 nM), NtrC was active in the absence of DNA, and activation occurred in parallel with the formation of high-molecular-weight aggregates. We infer that activation of NtrC involves an interaction between two NtrC-P dimers and proceeds in two steps. The first step is the phosphorylation of NtrC. The second step is the interaction between two NtrC-P dimers. This interaction induces the conformational change in NtrC-P to the active conformation.
Adenosine Triphosphatases↗
[The sleep apnea syndrome in patients with acromegaly].
The authors examined 19 nonselected patients with acromegaly (8 women and 11 men), incl. 16 where the disease was hormonally active, 3 had normal growth hormone values, 11 patients had a surgical operation of the pituitary. The examination was made by the MESAM 4 method (all-night recording of the heart rate, respiratory sounds, body position and arterial oxygen blood saturation). The sleep apnoea syndrome was diagnosed in 10 patients (52.6%). In patients where the sleep apnoea syndrome was not confirmed by MESAM 4, so-called intermittent snoring was found, an indirect sign of impaired ventilation during sleep.
Acromegaly↗
Femtosecond probing of sodium cluster ion Nan+ fragmentation.
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Journal Article↗
Phosphorylation of nitrogen regulator I of Escherichia coli induces strong cooperative binding to DNA essential for activation of transcription.
We studied the effect of phosphorylation of nitrogen regulator I (NRI) on its binding properties. Both phosphorylated and unphosphorylated NRI bind linearly to a single binding site but cooperatively to two adjacent binding sites. Cooperative binding of NRI is severely affected by phosphorylation: half-maximal binding of NRI-phosphate is at 20-fold lower concentrations than that of unphosphorylated NRI. This is more due to a huge increase in the cooperativity constant--which is the strength of interaction between two NRI dimers--than to an increase in the microscopic binding constant which is the binding affinity to a single binding site. In vitro transcription and DNA footprinting experiments showed that occupation of a single binding site by NRI is not enough for efficient activation and that activation only occurs at a higher NRI concentration. We propose an activation mechanism for NRI in which the phosphorylation of NRI induces a conformational change in the N-terminal domains of the NRI-phosphate dimers, which now interact strongly with each other, leading to a tetramerization of NRI upon binding to two adjacent binding sites. We propose that not the phosphorylation of NRI itself but rather the tetramerization of NRI-phosphate on DNA binding induces the conformational change of the central domain to the active conformation.
Bacterial Proteins↗
The relationship between short-term memory capacity and EEG power spectral density.
Multiplying memory span by mental speed, we obtain the information entropy of short-term memory capacity, which is rate-limiting for cognitive functions and corresponds with EEG power spectral density. The number of EEG harmonics (n = 1, 2,..., 9) is identical with memory span, and the eigenvalues of the EEG impulse response are represented by the zero-crossings up to the convolved fundamental, the P300. In analogy to quantum mechanics the brain seems to be an ideal detector simply measuring the energy of wave forms. No matter what the stimulus is and how the brain behaves, the metric of signal and memory can always be understood as a superposition of n pi states of different energy and their eigenvalues.
Brain↗
Preservation of the myocardial collagen framework by human growth hormone in experimental infarctions and reduction in the incidence of ventricular aneurysms.
We administered human growth hormone to a group of rats with experimental myocardial infarctions, in order to observe its action on the connective tissue repair process and the consequent effect on postinfarction ventricular aneurysms. Myocardial connective tissue displays a complex layout around each myocyte and among neighboring ones. It has been shown to be highly vulnerable to acute coronary ischemia which affects its diverse components in accordance with a precise timetable. The ultimate consequence of ischemia on connective tissue is the disappearance of intermyocytic links and the collagen weave that surrounds each cell. Damage to this collagen framework of the heart is responsible for the final disarray of myocytes, with a parallel effect to the myocytolytic actions of ischemia within the very structure of each cell. Hence, the appearance of postinfarction ventricular aneurysms seems to be related to failure in normal repair processes resulting from maturation of new collagen tissue into the area of myocardial necrosis. It has been shown that, besides the well-known actions on chondrocytes, hypothalamic-hypophyseal human growth hormone and somatomedins activate the fibroblasts. Administration of human growth hormone resulted in a significant decrease in the incidence of ventricular aneurysms. Scanning electron microscopy showed a good preservation of connective tissue components of myocardium. A different histological pattern of necrosis resulted in the treated group.
Animals↗