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Biomedical subjects

E Reiner

Publications and source records attributed to E Reiner.

At least 55 records · Page 3Linked to original sources
PubMed1982

Dimethylphosphorothioates. Reaction with malathion and effect on malathion toxicity.

Five dimethylphosphorothioates were tested for their toxicity to rats, potentiation of malathion toxicity in rats, inhibition of carboxylesterase in vitro, and reaction with malathion in vitro. The compounds were: potassium salts of (CH3S)2P(O)O-(I), (CH3O)(CH3S)P(O)S-(II), (CH3O)2P(O)S-(III), (CH3O)2P(S)S-(IV), and (CH3O)(CH3S)P(O)O-(V). The dimethylphosphorothioates are not toxic to rats (up to 1 g/kg, orally), they do not potentiate malathion toxicity in rats, and do not inhibit carboxylesterase activity in vitro (up to 1 mM concentrations). However, when the S-acid diesters (II, III, IV) are incubated with malathion for serveral days at room temperature or for several hours at 50 degrees C they become methylated forming the trimethylphosphorothioates OSS-trimethyl phosphorodithioate, OOS-trimethyl phosphorothioate and OOS-trimethyl phosphorodithioate respectively, which potentiate malathion toxicity. Furthermore, these same acid diesters increase the rate of isomerization of malathion into OS-dimethyl-S-(1,2-dicarbethoxyethyl) phosphorodithioate (isomalathion) particularly, diester IV. The formation of the trimethylphosphorothioates and isomalathion from the interaction of the S-acid diesters with malathion was determined by thin layer chromatography (TLC), gas chromatography and mass spectrometry and could be detected by in vitro inhibition of carboxylesterase. TLC methods can detect 1 mg of the trimethylphosphorothioates and isomalathion per gram malathion.

Animals↗
PubMed1982

Rehabilitation of micturition by transurethral electrostimulation of the bladder in patients with incomplete spinal cord lesions.

The effect of direct transurethral electrostimulation of the saline-filled bladder in 29 patients with bladder dysfunction after incomplete spinal cord injury is described. Following investigation by cystourethrography and cystomanometry, treatment was started from 14 days to 8 months after injury (average 3 months after injury). The method was considered to be very helpful in the rehabilitation of micturition. Twenty-six out of 29 patients gained normal bladder sensation, 25 achieved satisfactory detrusor contractions and 29 had low residual urines. Seventeen patients developed perfect bladder control and ten more were socially dry without the need for appliances.

Adolescent↗
PubMed1982

Rehabilitation of micturition in patients with incomplete spinal cord lesions by transurethral electrostimulation of the bladder.

Since the first description of the method of transurethral electrostimulation by Katona in 1956, controversial opinions have been published. In contrast to other types of electrical bladder stimulation the physiological basis for this method of treatment is the stimulation of receptors in the bladder wall. With the help of forceful stimuli damaged neurons may be activated leading to clinical success. This report presents our results over a 4-year period using stimulation parameters other than those published to date and studying the effects objectively by using urodynamic techniques. The results obtained in 30 adults with neurogenic bladder disturbance due to incomplete traumatic cord lesions will be presented under the following headings; development or alteration of bladder sensation or of detrusor contraction, the achievement of bladder control and the efficiency of micturition as shown by the decrease of residual urine. The method is helpful in the restoration of micturition in patients with incomplete traumatic spinal cord lesions: 26 out of 30 patients gained perfect bladder sensation, 25 of them achieved satisfactory bladder contractions, 28 ended the stimulation program with a residual below 50 cm3 and 17 out of 30 gained perfect bladder control, 10 others became at least socially dry without need for pads or urinals.

Adolescent↗
PubMed1981

Interaction of some trialkyl phosphorothiolates with acetylcholinesterase. Characterization of inhibition, aging and reactivation.

The reaction of bovine erythrocyte acetylcholinesterase (acetylcholine acetylhydrolase, EC 3.1.1.7) with a set of structurally related phosphorothiolates was studied in order to investigate the properties of the phosphorylated enzymes and to identify the leaving group. OOS- and OOS-trimethyl phosphorothiolates and their triethyl analogues inhibit acetylcholinesterase reversibly and by progressive inhibition, and the phosphorylated enzymes undergo both spontaneous reactivation and aging. For each compound the enzyme-inhibitor dissociation constant, and the rate constants for inhibition (ka), reactivation and aging have been derived. The OOS-compounds are more potent inhibitors than the OOS-compounds, and the derived inhibited enzymes reactivate and age faster. By comparing reactivation and aging rate constants with those obtained from phosphorylated enzymes of known structure it was concluded that the leaving group of during phosphorylation is the S-alkyl. SSS-trimethyl and -triethyl phosphorothiolates also form reversible complexes and inhibit the enzyme progressively. With these inhibitors the phosphorylated enzymes did not reactivate either spontaneously or in response to oximes under conditions successful for the other inhibitors. The ka values (37 degrees C, pH 7.4) range from 30 M-1 X min-1 (OOS-trimethyl phosphorothiolate) to 6.7 X 10(3) M-1 X min-1 (OOS-triethyl phosphorothiolate) as compared to 1.25 X 10(5) M-1 X min-1 determined for isomalathion (O, S-dimethyl S-(1,2-dicarbethoxyethyl)-phoshporodithioate), which was used as one of the reference compounds. If the inhibitory potency of the trialkyl phosphorothiolates is calculated from measurements made after a fixed preincubation time the results in ka values will be misleading.

Acetylcholinesterase↗
PubMed1981

Esterases in schistosomes: reaction with substrates and inhibitors.

Studies were made (at 37 degrees, pH 7.6) on the interaction of some organophosphorus compounds and carboxylic acid esters with cholinesterases (EC 3.1.1.7 and EC 3.1.1.8) and A-esterases (EC 3.1.1.2) in homogenates of Schistosoma mansoni (adults and cercariae) and Schistosoma haematobium (adults). The results are compared with those obtained from the same reactions in other parasitic helminths and in mammalian tissues. Metrifonate (0,0-dimethyl-2,2,2-trichloro-1-hydroxyethyl phosphonate) does not seem to react with cholinesterases from parasites or mammals. Dichlorvos (0,0-dimethyl-2,2-dichlorovinyl phosphate) is a phosphorylating inhibitor; the rate constants of inhibition of cholinesterases from schistosomes are in the order of 10(5) M-1 min.-1. Similar or lower rate constants (10(4) M-1 min.-1) are found for cholinesterase inhibition in other parasitic helminths and mammals. S. mansoni and S. haematobium hydrolyse carboxylic acid esters (10 mM) in decreasing order: phenylacetate (about 2 mumol per hour per mg protein), acetylthiocholine, propionylthiocholine, butyrylthiocholine. Dichlorvos (10 mM) is hydrolysed by S. mansoni and S. haematobium at about the same rate as by mammalian erythrocytes and human sera (about 10 mumol per hour per gram wet weight). Neither paraoxon (0,0-diethyl-4-nitrophenyl phosphate) nor methyl-paraoxon are hydrolysed by S. mansoni and S. haematobium, although both compounds are good substrates for mammalian A-esterases. The stability of metrifonate and dichlorvos in buffer solutions was also determined (at 37 degrees). Metrifonate is about equally stable in bicarbonate buffer (pH 7.6) and phosphate buffer (pH 7.4) (t 1/2 = 1.5 and 2.6 hrs, respectively), while dichlorvos is considerably more stable in bicarbonate (t 1/2 = (36 hrs) than in phosphate buffer (t 1/2 = 2.9 hrs).

Animals↗
PubMed1980

DDT residues in samples of human milk, and in mothers' and cord blood serum, in a continental town in Croatia (Yugoslavia).

Concentrations of p,p'-DDE, p,p'-DDD, and p,p'-DDT were determined in 34 samples of human milk obtained 3-5 days after delivery and in 37 samples obtained at later times of lactation (up to 55 weeks). All samples contained p,p'-DDE, but only several contained p,p'-DDD and p,p'-DDT. The concentrations of p,p'-DDE were 31 microgram/l in the beginning of lactation and 53 microgram/l at later time intervals. The concentration ranges in both groups overlap almost completely and the difference in the mean values is not significant. Serum samples from 35 mothers and cord blood were also analyzed. All samples contained p,p'-DDE, the concentrations being 18 microgram/l and 6.8 microgram/l in the mothers' and cord blood serum, respectively. Serum samples of 24 non-pregnant women contained the same amount of p,p'-DDE (20 microgram/l) as mothers' sera. All samples were collected in a continental town of Croatia (Yugoslavia) between 1977 and 1979. The concentrations of DDT residues were determined by gas chromatography, and two methods for extraction from milk were used and compared.

DDT↗
PubMed1979

Characterization of normal human cells by pyrolysis gas chromatography mass spectrometry.

Differentiation of normal human cells has been accomplished by pyrolysis gas chromatography mass spectrometry. Normal cells from human kidney, spleen, liver and brain tissues have been pyrolyzed and the products chromatographically separated and characterized by mass spectrometry. Molecular pyrolysis products giving rise to the characteristic pyro-mass chromatograms include, but are not limited to, alkenes, alkanes, nitriles and various ring compounds. Single ion mass chromatograms as well as multiple ion mass chromatograms have been used to explore the characteristic differences between various tissue materials. A dynamic computer methodology for comparing pyro-mass chromatograms has been developed for use in automatic identification and classification of the human cellular material.

Brain↗
PubMed1978

Botulism: a pyrolysis-gas-liquid chromatographic study.

Forty samples of dried Clostridia bacteria were subjected to pyrolysis-gas-liquid chromatography (PGLC). Examination of the key fingerprint peaks enabled the analyst to differentiate the samples into their respective antigenic groups. Peaks occurring at the high boiling end of profile could be used to distinguish proteolytic from non-proteolytic strains of C-botulinum. PGLC has proven to be a highly reproducible as well as a rapid specific method for differentiating and identifying samples of Clostridium botulinum.

Botulism↗