What does 'harder than diamond' mean?
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Diamond↗
Biomedical subjects
R Riedel
Publications and source records attributed to R Riedel.
[The "Spandau Public Health" test--description of study].
In 2002 the "Spandauer Gesundheitstest" ("Spandau Public Health" Test), a prospective cohort study of the Robert Koch-Institute in Berlin has been successfully going on for two decades. Ten waves of follow-up of this study are now available, in which approximately 7 000 adults were interviewed and examined. Approximately 770 participants have taken part in all ten follow-up waves. The "Spandauer Gesundheitstest" is carried out to provide information on changes in health state at the individual level over time. The main epidemiological aim of the study is to follow up the development and course of chronic disease together with changes in health care needs and utilisation. A questionnaire, blood and urine examinations and a medical interview are parts of the study design in every wave. Since the beginning of this study more than 900 participants died. A mortality follow-up is carried out regularly to investigate the cause of death of the participants. The data are available for analysis.
Adolescent↗
Implantation of recombinant human bone morphogenetic proteins with biomaterial carriers: A correlation between protein pharmacokinetics and osteoinduction in the rat ectopic model.
This study was carried out to determine the effect of recombinant human bone morphogenetic protein (rhBMP) pharmacokinetics (PK) on rhBMP-induced osteoinductive activity. It was our working hypothesis that the PK of a rhBMP significantly affects its osteoinductive activity. The PK of various rhBMPs (rhBMP-2, rhBMP-4, rhBMP-6, and chemically modified rhBMP-2) implanted with four biomaterial carries (Helistat, hDBM, Osteograf/N, and Dexon) was determined using (125)I-labeled proteins in the rat ectopic assay. A select combination of rhBMP and carriers then was evaluated in the rat ectopic assay for osteoinductive activity using a semi-quantitative histologic scoring system. The results indicate that initial protein retention is dependent on protein isoelectric point (pI); proteins with a higher pI yielded a higher implant retention. Subsequent PK was not strongly dependent on the pI or on the carrier. Because of the difference in early retention, the rhBMP-carrier combinations exhibited a >100-fold difference in implant-retained protein dose. When rhBMP-2 and rhBMP-4 were implanted with the carriers, more rhBMP-2 was retained in an implant, and the osteoinductive potency of rhBMP-2 typically was higher than rhBMP-4 at low implantation doses. We conclude that protein pI plays a significant role in the local retention of implanted rhBMP and that higher retention yields a higher osteoinductive activity.
Amino Acid Sequence↗
Animal pharmacology of reversible antagonism of the gastric acid pump, compared to standard antisecretory principles.
To define the basic antisecretory profile of a potassium-competitive antagonism of the gastric acid pump relative to other classes of acid-inhibitory drugs, they were compared to each other against all three major stimuli of acid secretion. Pumaprazole is an imidazo-pyridine derivative that was used in this investigation as an example of reversibly binding acid pump antagonists (APAs). It differs from covalently binding proton pump inhibitors (PPIs), such as omeprazole, both with respect to chemical structure and mode of interaction with the gastric H(+)/K(+)-ATPase (i.e., the acid or proton pump). The present data show that a single dose of pumaprazole is able to elevate intragastric pH in the dog with gastric fistula under pentagastrin or carbachol stimulation from pH 1 to about pH 7 while still displaying a dose-dependent, well-controlable duration of action of a few hours. Ranitidine at the same oral dose also shows a short duration of action, but combined with a far lower efficacy. By contrast, a single oral dose of the PPI omeprazole elevates intragastric pH for a longer time period, but this pH elevation is far lower compared to that of the APA. Regarding the less stringent parameter of inhibition of total acid output in the Heidenhain pouch dog, the modified Shay rat or the Ghosh-Schild rat, pumaprazole is, overall, slightly more efficacious than ranitidine. The M(1)-muscarinic antagonist pirenzepine is ineffective (against histamine stimulation) or far less effective than pumaprazole (against pentagastrin-stimulation), but as effective as pumaprazole against carbachol stimulation in the Ghosh-Schild rat. Basal acid output in the same model is more effectively inhibited by pumaprazole than by ranitidine. In conclusion, our data demonstrate the exceptional ability of a reversibly binding APA to elevate intragastric pH up to neutrality even upon a first administration while still displaying a limited, dose-dependent duration of action.
Animals↗
[Blunt tracheobronchial injuries in children].
Blunt tracheobronchial injuries in children are rare and are associated with many diagnostic problems. Based on the successful outcome in a seven- and a twelve-year-old patient operated within 12 hours after the accident the authors discuss the development of the symptomatology and early clinical, X-ray, bronchoscopic and CT diagnosis of rupture which are, if intensive care and early treatment of the injury are ensured, the basis for preserving normal pulmonary function and ensure prevention of sequelae due to obstruction and infection. The children were admitted to hospital for 22 and 14 days resp. and discharged in a good condition. The check-up examinations of both patients are within the normal range and there are no limitations as compared with healthy children of the same age.
Bronchi↗
[Incidence and etiology of psychotic disorders in HIV infected patients].
There are numerous case reports on psychoses in AIDS patients and, although more seldom, also in HIV-positive patients in early stages of infection; however, systematic investigations on the frequency, e.g., relevant for the indication of an HIV test in psychiatric patients, are missing. For this study, 1046 HIV-positive patients were examined regarding psychoses. A total of 301 patients (28.8%) were HIV-positive but asymptomatic, and 380 patients (36.2%) had the lymphadenopathy syndrome. One hundred thirty-two patients (12.6%) suffered from an AIDS-related complex and 233 patients (22.3%) from AIDS. Of these 1046 patients, only 9 (0.9%) suffered from psychoses. One patient with a paranoid-hallucinatory syndrome was asymptomatic; one in the lymphadenopathy syndrome was manic. The other 7 patients were all in late stages of the infection. A causal relationship between HIV infection and psychosis and probable in only 3 patients. These data do not indicate a markedly elevated prevalence of psychosis in HIV-positive or AIDS patients.
AIDS Dementia Complex↗
WHO Neuropsychiatric AIDS study, cross-sectional phase I. Study design and psychiatric findings.
BACKGROUND: Most available studies on the psychiatric, neuropsychological, and neurological complications of HIV-1 infection and AIDS have been conducted in Western countries, on samples of well-educated, mostly white, homosexual men. Concerns about generalizability of the results of those investigations prompted the WHO to implement the cross-cultural venture called WHO Neuropsychiatric AIDS study. METHODS: This project aims to assess the prevalence and natural history of HIV-1-associated psychiatric, neuropsychological, and neurological abnormalities in representative subject samples enrolled in the five geographic areas predominantly affected by the HIV-1 epidemic. Assessment is made by a data collection instrument including six modules. The intercenter and intracenter reliability in the use of each module has been formally evaluated. The study consists of a cross-sectional phase and a longitudinal follow-up. RESULTS: The cross-sectional phase was completed in five centers. This paper reports on the results of psychiatric assessment, which revealed a significantly higher prevalence of current mental disorders in symptomatic seropositive persons compared with seronegative controls among intravenous drug users in Bangkok and homosexuals/bisexuals in São Paulo. The mean global score on the Montgomery-Asberg Depression Rating Scale was significantly higher in symptomatic seropositive individuals than in matched seronegative controls in all centers. CONCLUSIONS: These results suggest that the significance of the psychopathological complications of symptomatic HIV-1 infection may have been underestimated by previous studies conducted on self-selected samples of well-educated, middle-class, mostly white, homosexual men.
AIDS Dementia Complex↗
Controlled MRI studies in psychiatric patients--relations to functional imaging methods (EEG mapping, SPECT and PET).
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Brain Mapping↗
Brain dysfunction in psychiatric patients during music perception measured by EEG mapping: relation to motor dysfunction and influence of neuroleptic drugs.
We report here our findings on music perception obtained as a companion study to the investigation with 16-channel EEG mapping in psychiatric patients during motor activation, published recently elsewhere. We decided to add on a study of this functional circuit, since there is evidence that it is disturbed in various psychiatric patient groups (another "functio laesa"). Involved in the study were 23 male and 25 female schizophrenics, 11 male and 18 female non-endogenously depressed patients (not presently under medication, i.e. drug-naive or wash-out period from 1 week to 17 years), 26 male and 37 female endogenously depressed patients (medicated with tri- or tetracyclic antidepressants and/or benzodiazepines; no lithium), and 22 male and 17 female control subjects (i.e. n = 179). We compared resting conditions after a special relaxation procedure with three music perception tasks: (1) a standardised rumba rhythm generated by a keyboard and delivered binaurally by earphones, (2) the same as an arpeggio in D major, and (3) the same as an arpeggio with a tonic-subdominant-dominant cadence. Major results were obtained in the delta and alpha frequency bands, yielding signs of "diffuse hyperactivation", most prominent in schizophrenic males, and not observed to a similar extent in any other patient group or in normal controls. Interestingly, there were major sex differences, yielding a more diffuse EEG activation pattern in normal females than in males and thus possibly obscuring signs of brain function diffusion in female patients. Viewing our broader evidence of similar brain dysfunction when examining motor functional circuits, especially in schizophrenics, these findings provide further evidence of a brain disorganization with lack of laterality/diffusion which may be found in subgroups of these patients and not in other psychiatric disorders. In schizophrenic patients, these EEG signs of "diffuse hyperactivation" on simple motor and/or music stimulation were reduced to nearly normal by neuroleptic medication. The latter finding may contribute to possible clinical applications of EEG mapping, considering the EEG's unique suitability for long-term brain function monitoring. Other neuroimaging methods like SPECT and PET should be used for additional "external validation".
Adolescent↗
Direct comparison between the ulcer-healing effects of two H(+)-K(+)-ATPase inhibitors, one M1-selective antimuscarinic and one H2 receptor antagonist in the rat.
A direct comparison of the ulcer-healing effects of two H(+)-K(+)-ATPase inhibitors (pantoprazole and omeprazole), one M1 antimuscarinic (telenzepine) and one H2 receptor antagonist (cimetidine) was performed in the rat. Gastric and duodenal ulcers were induced by local application of acetic acid and thereafter treated over 10 days by the test drugs. Overall and on a molar basis, ulcer healing was comparably accelerated by pantoprazole, omeprazole and telenzepine and less so by cimetidine. The same rank order was found with respect to the inhibition of gastric acid secretion in the modified Shay rat.
2-Pyridinylmethylsulfinylbenzimidazoles↗
BY 1023/SK&F 96022 INN pantoprazole, a novel gastric proton pump inhibitor, potently inhibits acid secretion but lacks relevant cytochrome P450 interactions.
The novel H+/K(+)-adenosine triphosphatase inhibitor (gastric proton pump inhibitor), BY 1023/SK&F 96022, was found to be more potent than omeprazole in some rat models and slightly less potent in a dog model. Overall, both compounds are of a similar potency and efficacy. BY 1023/SK&F 96022 exhibited a somewhat longer duration of the antisecretory action than omeprazole in the Ghosh-Schild rat. In the modified Shay rat, on the basis of equieffective doses in terms of the initial effect, both compounds had a comparable duration of action. However, the p.o./i.v. dose ratio upon acute administration was larger for omeprazole, possibly reflecting its lower stability in the acidic environment of the secreting stomach, compared to BY 1023/SK&F 96022. As in vivo, both compounds were equipotent to inhibit acid production in rabbit isolated fundic glands. However, omeprazole interacted with the 7-ethoxycoumarin dealkylase in vitro with high affinity (Ki = 38.5 mumol/l), in contrast to BY 1023/SK&F 96022 (Ki = 135 mumol/l). Compared to omeprazole, BY 1023/SK&F 96022 also showed less interaction with the cytochrome P450 enzyme hydroxylating ionazolac. Moreover, this difference between the two compounds was also found in the rat in vivo with respect to their interaction with diazepam. Thus, both compounds displayed a comparable antisecretory potency in vivo and in vitro but showed a different interference with cytochrome P450 in favor of less interaction by BY 1023/SK&F 96022.
2-Pyridinylmethylsulfinylbenzimidazoles↗
[A rational diagnostic program for hypertension in children].
Early screening of subjects liable to develop cardiovascular diseases is one of the main tasks of preventive cardiology of child age. The authors present a rational programme for the screening and diagnostic of hypertension in children, its aim being to differentiate primary and the most frequent secondary forms of hypertension; this will create prerequisites for its adequate treatment (non-pharmacological and pharmacological) as well as for dispensarization. Review.
Adolescent↗
The affinity, selectivity and biological activity of telenzepine enantiomers.
The binding of the enantiomers of telenzepine to muscarinic receptor subtypes present in guinea-pig cerebral cortex, myocardium and salivary glands has been examined. The (+) enantiomer is more potent in all assays and exhibits a greater selectivity than the (-) enantiomer for the different receptor subtypes. As a consequence, the enantiomeric potency ratio varies from ca. 400 (cortical 'M1' receptors) to ca. 50 (cardiac receptors). In functional assays in vitro in the rabbit vas deferens and rat atria, the affinity constants and enantiomeric potency ratios for the two isomers agree with those found for the appropriate muscarinic receptor subtype in binding assays. A high enantiomeric potency ratio, 180, is found in vivo for the ability of the telenzepine enantiomers to inhibit the production of lesions in the modified Shay rat preparation. The data are compatible with the blockade of M1 receptors by (+)-telenzepine being responsible for this action of telenzepine and would tend to exclude the possibility that the anti-ulcer action of telenzepine is mediated via a muscarinic or non-muscarinic action of the (-) enantiomer.
(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethy↗
[Treatment of status asthmaticus].
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Asthma↗
Comparison of the gastric antisecretory and antiulcer potencies of telenzepine, pirenzepine, ranitidine and cimetidine in the rat.
In different rat models, the antisecretory and antiulcer effects of the M1-antimuscarinics telenzepine and pirenzepine, the nonselective antimuscarinic atropine, and the H2-blockers ranitidine and cimetidine were compared to each other. Intravenous telenzepine proved to be more potent in inhibiting gastric acid secretion in the Ghosh-Schild rat (carbachol-stimulated), the chronic fistula rat (basal secretion), or, both intravenously and orally, in the modified Shay rat, as compared to pirenzepine, cimetidine or ranitidine. After intravenous administration, only atropine was equally potent to telenzepine in all three models, but it was less potent than telenzepine after oral administration in the modified Shay rat. Gastric mucosal lesions induced by pylorus ligation plus acetylsalicyclic acid or acetylsalicyclic acid plus HCl were best inhibited by telenzepine and atropine, with pirenzepine, ranitidine and cimetidine being less potent, their relative potencies depending on the particular experimental model used. Thus, among the antiulcer drugs tested, telenzepine was the most potent one with respect to both antisecretory and antiulcer activity. Moreover, the duration of the antiulcer effect of telenzepine proved to be significantly longer than that of pirenzepine in the modified Shay rat.
Animals↗
[Treatment of drug-resistant focal epilepsy using visual orientation activity].
A 24 year old female with drug-resistant epilepsy showed control over her complex-partial seizures. The patient suppressed paroxysmal activity up to 20 minutes. There was evidence of a relation between the occipital localization of the epileptic focus and the mode of control. Under controlled conditions increase of the visual activity was associated with decreasing paroxysmal activity. Especially varying visual orientation suppressed epileptic activity, while visual focusing or closed eyes enhanced it. Neither auditory nor somatosensory activity interfered with paroxysms. The comparison between 32 weeks before and 12 weeks after the study showed a significant reduction of the weekly seizure frequency. The possibility of a "sensory control" of epileptic activity is discussed.
Adult↗
Specificity of the substituted benzimidazole B 823-08: a prodrug for gastric proton pump inhibition.
Substituted benzimidazoles are potent inhibitors of the parietal cell proton pump, the H+/K+-ATPase. One member of this group, the sulfide B 823-08 (2-[(4-methoxy-3-methyl-2-pyridylmethyl)-thio]-5-trifluoromethyl-(1H)- benzimidazole) inhibits gastric acid secretion in various in vivo models, but fails to affect acid secretion in the isolated, lumen perfused mouse stomach. In contrast, the corresponding sulfoxide (B 823-10) is active under both in vivo and in vitro conditions. Since the sulfide is metabolically transformed to sulfoxide in vivo, the sulfide behaves as a prodrug of the sulfoxide. No effects of biological significance are found on organ functions which critically depend on Na+/K+-ATPase activity. This is in line with observations that the sulfoxide needs activation in an acidic environment, which constitutes the basis of its specificity for inhibiting stimulated parietal cells.
2-Pyridinylmethylsulfinylbenzimidazoles↗
The sulphoxide moiety of substituted benzimidazoles is essential for inhibition of parietal cell K+/H+-ATPase.
The antisecretory action of the benzimidazole sulphoxide derivative B 823-10, 2[(4-methoxy-3-methyl-2-pyridylmethyl)-sulphinyl]- 5-trifluoromethyl(1H)-benzimidazole, was compared with the effect of the corresponding sulphide B 823-08 in several in vivo and in vitro and in vitro test systems. The sulphide B 823-08 and the sulphoxide B 823-10 were found to be equipotent in the Shay rat. The sulphide was found to inhibit H+ secretion in intact rabbit gastric glands and enriched guinea-pig parietal cells with lower potency than the corresponding sulphoxide. The relative potency in antisecretory activity (sulphide/sulphoxide) decreased in the following rank order: Shay rat: gastric glands: parietal cells. Purified K+/H+-ATPase was not blocked by the sulphide, whereas the sulphoxide inhibited the overall as well as the partial reactions of this enzyme. In all in vitro systems tested, inhibition of H+ secretion and enzyme activity by the sulphoxide, but not by the sulphide, was antagonized by SH-compounds such as dithiothreitol. It is concluded that in vivo sulphoxidation of the sulphide plays an important role in acid inhibition. In vitro an additional inhibitory mechanism of the sulphide has to be considered.
2-Pyridinylmethylsulfinylbenzimidazoles↗