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Biomedical subjects

J Knoll

Publications and source records attributed to J Knoll.

At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

Undifferentiated embryonal sarcoma with unusual features arising within mesenchymal hamartoma of the liver: report of a case and review of the literature.

Undifferentiated embryonal sarcoma (UES) is a rare and highly malignant hepatic neoplasm, affecting almost exclusively the pediatric population. It has replaced malignant mesenchymoma, under which diagnostic term the first three cases were described. A link between embryonal sarcoma and mesenchymal hamartoma of the liver (MHL) has long been proposed, because of clinicopathologic overlaps of these entities; however, until recently, this association remained tenuous. Cases of UES arising in a background of mesenchymal hamartoma of the liver have previously been reported in two teenage girls. Discovery of a similar genetic abnormality in MHL and UES has clinched the supposed link between them. There have also been two reports of UES with prominent cystification, one associated with peripheral eosinophilia, and thereby masquerading as hydatid cyst of the liver. We report a case of UES arising in a young boy with MHL, with unusual histologic features, including large mesothelial-lined cysts and ectopic adrenal cortical tissue under Glisson's capsule.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Sexual performance and longevity.

Sexually inactive ("low-performing," LP) and highly active ("high-performing," HP) rats were selected from a sexually inexperienced population. Saline control LP rats (n = 44) lived 134.58 +/- 2.29 weeks, their HP peers (n = 49) lived 151.24 +/- 1.36 weeks. Life-long treatment with 0.25 mg/kg (-)deprenyl, a selective inhibitor of MAO-B that also stimulates action potential-transmitter release coupling in the catecholaminergic neurons in the brain (catecholaminergic activity enhancer, CAE, effect), enhanced the sexual and learning performance of both LP and HP rats and prolonged their life. LP rats (n = 48) treated with (-)deprenyl lived 152.54 +/- 1.36 weeks and HP rats on (-)deprenyl (n = 50) lived 185.30 +/- 1.96 weeks. As an indicator of the basic activity of catecholaminergic neurons, the resting release of dopamine from the striatum, substantia nigra, and tuberculum olfactorium, and of norepinephrine from the locus coeruleus, was measured in 2-, 4-, 8-, 16-, and 32-week-old male and female rats. The release of transmitters between weaning and the second month of age, i.e., during the crucial developmental phase of life, was significantly higher than either before or after that period, indicating that a CAE mechanism starts working with high intensity after weaning, lasts until the completion of full scale sexual development, and shows an unparalleled decay thereafter. It was concluded that the CAE regulation in the brain, stimulated by (-)deprenyl, controls general activity and consequently the longevity of rats.

Animals↗
PubMedDate not supplied

The organisation of paediatric renal care in different European countries: results of the PAC project.

The Paediatric Access Care (PAC) project, organised by the Research Board of EDTNA/ERCA, aimed to study the organisation of paediatric renal care in Europe and to investigate the practice of access care for both haemodialysis (HD) and peritoneal dialysis (PD) paediatric patients. This paper reports on the organisation of paediatric renal care. The majority of paediatric renal care units were located in specific paediatric units of university hospitals. Most of the centres had offered HD, PD and transplantation (Tx) for more than 20 years. Half of nursing staff had qualifications in paediatric and renal nursing. Most of the centres offered an extended multidisciplinary team approach with the family actively involved in the care of the patient. PD and HD were equally used. Automatic Peritoneal Dialysis (APD) was offered as the standard PD treatment in 2 out of 3 centres. The HD schedule mostly utilised was 3 x 4 hours a week. Half of the patients were on the Tx waiting list and one third of registered patients were transplanted in 2004.

Adolescent↗
PubMedDate not supplied

Paediatric access care in Europe: results of the Paediatric Access Care (PAC) project.

Part two of the Paediatric Access Care (PAC) project, a research project of EDTNA/ERCA, investigated PAC in HD and PD patients including the policy for the creation and maintenance of access, and the registration of access related complications that occurred during the registration year of 2004. Data were collected from 39 centres of 13 European countries and included 379 paediatric patients. Fatal complications, resulting in terminating the use of the access, were noted in 59 HD and 22 PD patients. Paediatric access care varied considerably between European centres and in many areas consensus or best practice evidence is still lacking. There is a need for recommendations for the paediatric renal nurse, handling access care in the paediatric renal population.

Arteriovenous Shunt, Surgical↗
PubMedDate not supplied

Plasma adrenocorticotropin concentration in healthy horses and in horses with clinical signs of hyperadrenocorticism.

Pituitary adenomas are commonly reported in older horses. The typical clinical signs associated with this condition, also known as equine Cushing's disease (ECD), are related to increased adrenocorticotropin (ACTH) production resulting in hyperadrenocorticism. The primary purpose of this study was to determine whether plasma ACTH concentrations differed between cushingoid and healthy horses. The second objective was to determine the effects of blood sample handling techniques on ACTH concentrations. A commercial human ACTH radioimmunoassay (RIA) was used to quantify equine plasma ACTH. Intra-assay and interassay variations, as well as dilutional parallelism were determined during the RIA validation. Plasma ACTH concentrations were evaluated in a group of healthy equids composed of 18 horses and 9 ponies, and in 22 equids with a clinical diagnosis of hyperadrenocorticism (11 horses and 11 ponies). The mean plasma ACTH concentrations in healthy horses and ponies, (18.68 +/- 6.79 pg/mL (mean +/- SD) and 8.35 +/- 2.92 pg/mL, respectively), were significantly different (P = .009). The mean plasma ACTH concentration in horses and ponies with ECD, (199.18 +/- 182.82 pg/mL and 206.21 +/- 319.56 pg/mL, respectively), were significantly higher than the mean ACTH concentration in the control animals (P < .001). Plasma ACTH concentrations appeared to be a sensitive and specific indicator of ECD in horses and ponies. ACTH concentrations measured in plasma samples kept at room temperature (19 degrees C) as long as 3 hours after blood collection were not statistically different from those of samples kept at 1 degree C.

Adrenal Cortex Diseases↗
PubMedDate not supplied

Inflammation and writhing syndrome inducing effect of PGE1, PGE2 and the inhibition of these actions.

The inflammatory and nociception inducing effect of PGE1 and PGE2, and the inhibition of these actions were studied. The inflammatory effect was produced in rat paw by intradermal injection of PG. Both PGE1 and PGE2 in doses of 500 ng produced maximal inflammatory and vascular permeability increasing effects. With higher doses these responses decreased. Antiserotonin, antihistamine drugs partly antagonized the above mentioned effects of PG.

Acetates↗
PubMedDate not supplied

The pharmacology of 1-phenyl-2-propylamino-pentane (PPAP), a deprenyl-derived new spectrum psychostimulant.

The peculiar tyramine uptake inhibitory effect of (-)deprenyl prompted structure-activity relationship studies aiming to develop new spectrum central nervous system stimulants which are devoid of MAO inhibitory potency and operate de facto as indirectly acting, nonreleasing sympathomimetics. Of the derivatives synthesized for this purpose, 1-phenyl-2-propylaminopentane (PPAP) was selected as the reference substance and its pharmacological spectrum is presented. PPAP is taken up by the catecholamine axon terminal membrane and the vesicular membrane but it is devoid of catecholamine-releasing property. As a result, PPAP is, by interference, a potent inhibitor of the uptake of indirectly acting sympathomimetic releasers and of the catecholamine transmitters. This was proved, on the one hand, by measuring the uptake of [14C]PPAP into the catecholaminergic axon terminals and the inhibition of the uptake of [3H]noradrenaline and [3H]dopamine by PPAP in the rat brain, and, on the other hand, on the pulmonary artery strip of the rabbit and, in vivo, using the rat nictitating membrane as a detector. PPAP increases motility at 2 mg/kg and, in contrast to amphetamine, inhibits it at very high doses (50 mg/kg) only. A two-sided antagonism in the motility-increasing effect between PPAP and amphetamine and, more pronounced, between PPAP and mazindol was detected. PPAP is substantially less effective in inducing stereotyped behavior than either amphetamine or methamphetamine. PPAP facilitates learning and retention, is highly potent in antagonizing the tetrabenazine-induced depression in behavioral tests and is very effective in the forced swimming test. Whereas amphetamines facilitate performance in a very narrow range of low doses, which turns, at a modest elevation of the dose, into the opposite effect, PPAP improves performance within a reasonably broad dose range. Based on the peculiar pharmacological profile of PPAP, its potential usefulness in depression, in Alzheimer's disease and in attention-deficit-hyperkinetic disorder seems to be plausible.

Animals↗
PubMedDate not supplied

Two kinds of opiate receptor.

Studies with azidomorphine derivatives have revealed that some of them, particularly N-cyclopropylmethylnorazidomorphine (CAM), stimulate some opiate receptors, while inhibit the others. The opiate receptors stimulated by CAM are called opiate A receptors, while those antagonized by CAM are called opiate B receptors. Opiate receptors are located at nerve terminals and upon stimulation decrease the release of a neurotransmitter. Opiate A receptors are most probably located at cholinergic nerve terminals, are present in the guinea pig ileum, mouse vas deferens and in the brain. Their stimulation leads to constipation and mental clouding. Opiate B receptors located on adrenergic nerve terminals are present in the cat nictitating membrane and in the brain. Their stimulation produces analgesia, depression of coughing and respiration, catalepsy, and mental clouding.

Animals↗