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Biomedical subjects

L Singer

Publications and source records attributed to L Singer.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Magnesium in bone mineral: an in vitro study.

The solubility of magnesium in bone mineral from control and magnesium-dificient rats receiving varying fluoride intakes was assessed. Evidence for the existence of a fluoride-related pool of skeletal magnesium possessing a diminished solubility was obtained.

Animals↗
PubMedDate not supplied

[Memory disorders in schizophrenia].

The current interest in memory disorders in schizophrenia results from the way perceptions of schizophrenia--whose organic origin is becoming increasingly evident--and memory--according to which there exist not one, but several memories--have developed. Memory disorders in the schizophrenic cannot be considered in isolation from knowledge accumulated in other areas of the cognitive and neuro-sciences; a more detailed understanding of these disorders requires a comparison of the different cognitive approaches, both with each other and with the neurobiological and clinical approaches, so that they can be integrated. Despite numerous methodological and conceptual difficulties, it now appears to have been established that the schizophrenic's memory deficit should be seen in the context of a wider cognitive deficit, that the memory tasks are not all disturbed and that the memory deficit cannot be identified with one specific form of memory. Thus, iconic formation, short-term memory in the traditionally accepted sense and implicit memory are hardly, if at all, affected; in contrast, the early processing of information, working memory and explicit memory are disturbed, probably to the extent that they require the implementation of strategies to organise the information to be memorized. Finally, in certain tasks, such as those evaluating latent inhibition or negative priming, schizophrenics perform better than normal subjects, suggesting that schizophrenics' cognitive deficit is localised. This profile of memory disorders is compatible with a dysfunction predominating in the frontal and temporo-hippocampal regions. Neuroleptics and anticholinergics have opposite effects on cognitive and mnesic performance, which is improved by the former and aggravated by the latter. The influence of clinical symptoms, positive or negative, institutionalisation of patients and chronic tardive dyskinesia is unclear. Among the theoretical proposals put forward to account for the observed disorders, those relating to a disturbance of the action planning process and to that of the internal representation of context are compatible with the observed memory disorders. All the clinically derived data and those produced by the cognitive and neurosciences indicate a need to reformulate the links between memory, selective attention and evaluation of the relevance of a stimulus, to develop a general model of the reciprocal interactions between cognition and affectivity and to look for the origin of a pathology as complex as schizophrenia, not in a local lesion in an isolated cerebral structure but in a disturbance of the dynamic interactions within a functional, parallel and distributed network of broadly interconnected regions.

Antipsychotic Agents↗
PubMedDate not supplied

Operative treatment of Brodie's abscess.

This manuscript deals with a unique operative management of unilateral Brodie's abscess in a 16-year-old male. Brodie's abscess is a common finding in childhood osteomyelitis. A review of the radiographic appearance, clinical presentation, and surgical management is presented.

Abscess↗
PubMedDate not supplied

[Rehabilitation of patients with schizophrenia].

Follow-up of 17 schizophrenic patients on long- or very long-term treatment (3 to 27 years), sectorial follow-up of a group of 57 schizophrenics since 1984 and 24 new patients since 1988, study on the development of 50 schizophrenics followed in an out-patient treatment centre and who had left this centre since 1987, are reported. The authors present their findings on their patients' socio-professional insertion or re-insertion. Thanks to progress in therapy, the long-term follow-up of schizophrenic out-patients is now possible. Complete hospitalisation can be avoided or its duration generally reduced. Socio-professional insertion or re-insertion depends on a certain number of factors affecting the observance by the patient and the regular following of his treatment. These factors and the evolution of the disorders are often unforeseeable, and render the patient's re-insertion problematical. The quality of the re-insertion also depends on the care possibilities available to the patient: sectorial follow-up, job-aid centre, sheltered workshops, associative apartments, leisure. Whatever the case, professional insertion seems much more limited than social insertion. Professional life can however be envisaged in subordinate work or in a sheltered working environment where the schizophrenic feels safe within a definite, fixed architectural and affective frame of reference.

Adult↗
PubMedDate not supplied

Preclinical development and characterization of an intravenous dosage form for the ACE inhibitor RS-10029.

Preclinical development of an intravenous dosage form for the ACE inhibitor RS-10029 involved the formulation and characterization of the drug's chemical/physical stability in two prototype formulations (injectable solution and lyophilized powder). Included in these studies were quantitative evaluations of various processing and administration parameters (membrane qualification, terminal sterilization, compatibility/delivery of the drug with typical infusion fluids and administration sets) on finished product integrity and quality. Analytical methodology used in these studies consisted primarily of a stability specific HPLC assay and a light obscuration based sensor (HIAC) for particulate matter analysis. Results of these studies indicate that the drug is relatively stable at ambient temperature and under accelerated storage conditions (predicted T90 at 25 degrees C greater than 2 yr, and T90 at 50 degrees C greater than 2 mo). However, the ability of the product to withstand a full terminal sterilization cycle is limited, and therefore other approaches toward sterile processing were examined. With regard to the stability and compatibility of the drug in a variety of fluids and devices there appears to be no overt limitations in its use for either bolus or infusion delivery.

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

[Interaction between non-steroidal anti-inflammatory agents and lithium salts].

Since the first observation in 1978, it has been clearly established that the non-steroidal anti-inflammatory drugs (NSAIDs) interfere with the pharmacokinetics of lithium: by reducing urinary clearance of the metal, they can raise the plasma lithium level and thus lead to intoxication. Among the NSAIDs available in France, this interaction has been reported with phenylbutazone (Butazolidine, Carudol), diclofenac (Voltarène), indomethacin (Indocid) and its antalgic derivative clomethacin (Dupéran), ketoprofen (Profenid), mefenamic acid (Ponstyl), niflumic acid (Nifluril) and piroxicam (Feldène). This interaction does not occur with aspirin; this exception suggests that the inhibition of prostaglandins synthesis is not the mechanism responsible for the decrease in the urinary elimination of lithium linked with an increase in its tubular reabsorption. In practice, in view of the growing diffusion of NSAIDs, it is necessary to inform all patients under lithium treatment of the risk of interaction resulting from their use.

Animals↗
PubMedDate not supplied

[Theophylline and urinary elimination of lithium in the anesthetized dog].

The effect of theophylline (intrarenal perfusion of 1.2 then of 2.4 mg/kg for two successive 15 minute periods) on urinary lithium elimination was studied in 6 pentobarbital anaesthetized dogs perfused with intravenous lithium chloride. Lithium and inulin clearance and the urinary elimination of sodium, potassium and phosphate were studied. Theophylline increases lithium clearance, glomerular filtration and salidiuresis. This salidiuretic effect partly linked to the inhibition of the proximal reabsorption of sodium attested by the rise in phosphate elimination contrasts with the absence of modifications in the fractional tubular reabsorption of lithium. Under our experimental conditions the increased lithium clearance seems linked to the increased glomerular filtration.

Anesthesia↗
PubMedDate not supplied

[Different effects of tricyclic (clomipramine and amitriptyline) and tetracyclic (maprotiline) antidepressors on the release of thyroid stimulating hormone, prolactin and growth hormone to thyrostimulating releasing hormone in patients with psychoaffective disorders (author's transl)].

The hormonal alterations induced by tricyclic and tetracyclic antidepressors (AD) were studied in patients with psychoaffective disorders (PAD) to ascertain the role of certain biogenic amines in the regulation of thyroid stimulating hormone (TSH), prolactin (PRL) and growth hormone (GH). The responsiveness of plasma TSH, PRL and GH to synthetic thyrostimulating release hormone (TRH; 250 microgram i.v.) was determined in 57 patients distributed in 5 groups according to the treatment: 10 non treated patients, 16 tricyclic (clomipramine and amitriptyline) treated patients, 6 patients treated by clomipramine in association with lithium, 6 tetracyclic (maprotiline) treated patients and 19 patients treated by major neuroleptics. Results of untreated patients were compared to those observed in 10 age and sex matched normal subjects. Basal plasma levels of TSH were normal in all the patients. The TSH response to TRH (delta TSH) was blunted in non treated patients. delta TSH was normal in the patients treated by maprotiline or neuroleptics and increased in the group treated by tricyclic AD in association with lithium. Basal plasma levels of PRL and PRL response to TRH (delta PRL) were decreased in the women treated by tricyclic AD, but remained normal under maprotiline. They were markedly increased in the neuroleptic group. No inadequate response of GH to TRH was noted in our series of patients. The different hormonal effects induced by AD--dissociation between delta TSH and delta PRL under tricyclics and normal or increased delta TSH under maprotiline--may be logically explained by the various ways of action of these AD on the brain monoamines. delta TSH decrease and tendency to an increased delta PRL observed with clomipramine argue for a serotoninergic regulation of these two hormones, whereas the normalisation of delta TSH under maprotiline argues for a noradrenergic regulation of this hormone. Effectively, tricyclic AD inhibits mainly the serotonin recaptation and tetracyclic inhibits rather norepinephrine recaptation. The persistent delta TSH increase observed in the group treated by the association clomipramine-lithium demonstrates that the tricyclics do not interact with the hypophyso-thyroid positive feedback.

Adult↗