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Biomedical subjects

J Deutsch

Publications and source records attributed to J Deutsch.

At least 19 recordsLinked to original sources

Electron-impact and chemical ionization detection of nicotine and cotinine by gas chromatography-mass spectrometry in rat plasma and brain.

Nicotine and its metabolite, cotinine, were measured in rat plasma and brain by gas chromatography-mass spectrometry. Both agents were extracted from plasma and brain, separated on a capillary column, and quantified by single-ion monitoring. The major fragment ions of nicotine and cotinine at m/z 84 and m/z 98, respectively, were monitored by electron-impact ionization detection and the protonated molecular ions at m/z 163 and m/z 177, respectively, were monitored by chemical ionization detection. Both compounds were quantified using deuterium-labeled nicotine and cotinine, respectively, as internal standards.

Animals

Red cell aplasia responsive to immunoglobulin therapy as initial manifestation of human immunodeficiency virus infection.

A patient who presented with pure red cell aplasia as the initial manifestation of human immunodeficiency infection is described. The patient had no signs of other autoimmune processes or immunologic or histologic evidence of parvovirus B19 infection, although we detected parvovirus B19 DNA in his serum. This patient had a complete, although temporary, response to a single course of immunoglobulin therapy and is currently responding to a second treatment.

Adult

Removal of scleral explant elements: a 10-year retrospective study.

There are several studies in the American literature on the incidence and causes of retinal redetachment following removal of explants. This is, to our knowledge, the first such study from Britain and differs in its findings from the American experience. The reason for removal of explants, the time of removal after initial detachment surgery and the consequences of removal were reviewed for the 10-year period from 1980 to 1990. During this period 1898 retinal detachment operations were performed at this centre, with an explant removal rate of 3.2% (61 eyes). Extrusion of the element was the cause in 74%. Of these 8% subsequently suffered a redetachment. In two eyes no retinal break was identified at initial surgery. Both of these suffered a redetachment following removal of the explant. Contrary to previous reports, redetachment was not related to short periods of explant or to infection of the explant. This study suggests that explant removal is a safe procedure. However, there is a significant risk of redetachment after explant removal if no breaks are identified at the time of initial surgery.

Adolescent

Myxoma mix-up. A case report.

We present a 63-year-old lady who had atrial myxoma. The diagnostic difficulties distinguishing this from giant cell arteritis are highlighted. In particular, both conditions caused choroidal and retinal infarcts, anterior ischaemic optic neuropathy, with raised acute phase reactants. The authors stress the importance of continued ophthalmoscopy as the fundal changes become more apparent.

Diagnosis, Differential

Eyelid leishmaniasis in a patient with neurogenic ptosis.

A patient with chronic progressive external ophthalmoplegia contracted cutaneous leishmaniasis of the upper eyelid. Infection of this site is rare because eyelid movements usually prevent the sandfly vector from biting the skin there. It is postulated that the relative immobility of the upper eyelid in this patient was a major predisposing factor for the infection.

Antimony Sodium Gluconate

Identification of 11,13-dihydroxy-14-octadecaenoic acid as a circulating Na+/K(+)-ATPase inhibitor.

Two digitalis-like compounds (DLC) were purified to homogeneity from bovine plasma. The purification procedure consisted of organic extractions and batch chromatography followed by three subsequent separations using reverse-phase high-performance liquid chromatography. The presence of a DLC in the different fractions was monitored by their ability to inhibit (a) [3H]ouabain binding to rat brain synaptosomes, and (b) microsomal Na+/K(+)-ATPase activity. Using mass spectrometry and nuclear magnetic resonance spectroscopy the structure of one of the DLCs was identified as 11,13-dihydroxy-14-octadecaenoic acid. It is suggested that this new hydroxy, unsaturated, fatty acid derivative may regulate Na+/K(+)-ATPase activity under some physiological and pathological conditions.

Animals

Brain and plasma pharmacokinetics and anticancer activities of cyclophosphamide and phosphoramide mustard in the rat.

By a sensitive and quantitative fluorometric assay, brain and plasma time-dependent concentration profiles were generated for phosphoramide mustard (PM) and active alkylating metabolites derived from cyclophosphamide (CPA) administration to rats. Whereas PM rapidly disappeared from plasma, with a monophasic half-life of 15.1 min, equimolar administration of CPA generated active metabolites in plasma that disappeared monoexponentially, with a composite half-life of 63 min. As a consequence, the time-dependent concentration integral of active alkylating metabolites derived from CPA administration, calculated between 5 min and infinity, was 3-fold that of PM. Pharmacokinetic parameters were calculated for each compound. The brain/plasma concentration-integral ratios of PM and active alkylating metabolites derived from CPA were 0.18 and 0.20, respectively. The cerebrovascular permeability-surface area product of PM was 7.5 x 10(-5) s-1, which is similar to that of other water-soluble anticancer agents that are restricted from entering the brain. The activities of a range of daily doses of PM and CPA were assessed against subcutaneous and intracerebral implants of Walker 256 carcinosarcoma tumor in rats. Inhibition of subcutaneous tumor growth by 50% was caused by CPA and PM doses of 6.6 and 12.0 mg/kg (daily for 5 consecutive days, starting 36 h after tumor implantation), respectively. However, administration of daily doses of up to 40 mg/kg did not significantly increase the survival of animals with intracerebral tumor implants. These studies indicate that active metabolites of CPA are restricted from entering the brain and that only subtherapeutic concentrations are achieved in brain tissue after systemic administration of CPA or PM.

Animals

Photorefraction: two methods and their clinical applications.

Photorefraction is an increasingly used research screening tool and numerous studies have demonstrated the simple and effective techniques available. This article describes the eccentric (off axis) and isotropic methods in detail, including the costs and difficulties involved. It is likely that photorefractive screening will become more widespread in its use as a screening tool in detecting the early factors responsible and associated with delayed visual maturation in the very young and that hospital departments of medical illustration may have to become conversant with the use of this new tool.

Amblyopia

[Cholestatic jaundice and hypophosphataemia in parenterally-fed premature infants--coincidence or causal connection? (author's transl)].

A report is presented of the chemical pathological findings in 14 premature and one full-term infant receiving almost exclusively parenteral nutrition during the first two weeks of life. Six infants developed cholestatic jaundice. The underlying diseases were the idiopathic respiratory distress syndrome in 10, gastroschisis in 3 and renal insufficiency in 1, while one was an otherwise healthy small for dates infant. After parenteral nutrition had been discontinued obstructive jaundice cleared by the third month of life except in one infant. Apart from the higher glucose intake during the second week, jaundiced infants principally differed from non-jaundiced infants by the development of significant hypophosphataemia. An attempt was made to correlate aetiologically the presence of cholestatic jaundice with the finding of hypophosphataemia on the possible basis of a disturbance of energy metabolism.

Abdominal Muscles

[Summer holiday camps for asthmatic children--an attempted assessment (author's transl)].

118 schoolchildred (males:females = 2.5 : 1) with bronchial asthma--defined as recurrent allergic or non-allergic expiratory dyspnoea--were investigated as regards their clinical course, frequency of asthma attacks, exercise tolerance, anti-asthmatic drug requirements and spirometric changes during and after participation in specialized holiday programmes during the summer months in 1974, 1975, and 1976. Clear-cut improvement was observed with regard to asthma attack frequency (up to nearly 100%) and drug requirements (up to 76%). Steroid dependence was observed in most cases. No significant spirometric improvement was demonstrable. All data require critical evaluation and interpretation in view of seasonal variations in asthmatic manifestation and the influence of environmental factors. On reviewing the results it is concluded that treatment of the asthmatic child by supervised high altitude holidays (1400 m above seal level), combined with physical training and a respirator re-education programme, is still a justified therapeutic approach, but it cannot replace specific therapy laid down on the basis of careful diagnostic testing. Particpation of the asthmatic child in school gym classes is recommended. Abstention from physical exercis due to a misplaced protective attitude is not beneficial in most cases.

Altitude

Regio- and stereoselectivity of various forms of purified cytochrome P-450 in the metabolism of benzo[a]pyrene and (-) trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene as shown by product formation and binding to DNA.

Highly purified cytochromes P-450(LM2) and P-450(LM4) and partially purified P-450(LM1), P-450(LM3b), and P-450(LM7) from rabbit liver microsomes exhibit different catalytic activities in the metabolism of benzo[a]pyrene (BzP) and (-)-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene [(-)trans-7,8-diol] in a reconstituted enzyme system. The two highly purified cytochromes also exhibit differences in the activation of BzP and (-)trans-7,8-diol to intermediates that bind to DNA, as well as in the stereoselective conversion of (-)trans-7,8-diol to the highly mutagenic and carcinogenic diol-epoxides r-7,t-8-dihydroxy-t-9,10-oxy-7,8,9,10- tetrahydrobenzo[a]pyrene (diol-epoxide I) and r - 7,t - 8 - dihydroxy - c - 9,10 - oxy - 7,8,9,10 - tetrahydrobenzo[a]pyrene (diol-epoxide II). P-450(LM2) is more active than P-450(LM4) in the metabolism of BzP and in its conversion to products that bind to DNA. In contrast, P-450(LM4) is more active than P-450(LM2) in the metabolism of (-)trans-7,8-diol and in its conversion to products that bind to DNA. The ratio of activity (percent substrate metabolized) with BzP relative to that with (-)trans-7,8-diol is 21 for P-450(LM2) and 0.3 for P-450(LM4); P-450(LM1), P-450(LM3b), and P-450(LM7) gave intermediate ratios. Marked stereoselectivity in the oxygenation of the (-)trans-7,8-diol to the highly mutagenic and putatively carcinogenic diol-epoxides I and II was observed with P-450(LM4), whereas the other preparations showed less selectivity. The ratio of diolepoxide I to diol-epoxide II ranges from 0.3 for P-450(LM7) to 11 for P-450(LM4). The substrate specificity and regio- and stereo-selectivity of the different forms of cytochrome P-450 may regulate the balance between activation and detoxification pathways of BzP and therefore determine the susceptibility of individual tissues, strains, and species to the carcinogenic action of BzP.

Animals

Maleimide as an inhibitor in measurement of erythrocyte glucose-6-phosphate dehydrogenase activity.

Erythrocyte glucose-6-phosphate dehydrogenase activity is measured with a centrifugal analyzer by use of a commercial reagent kit and of the reaction glucose-6-phosphate + NADP+ leads to 6-phosphogluconolactone + NADPH. Rate of production of NADPH is measured and related to hemoglobin concentration. Maleimide is added to inhibit further production of NADPH in a secondary reaction by endogenous 6-phosphogluconate dehydrogenase. The method is compared with others that are designed to circumvent the secondary reaction by either (a) addition of excess phosphogluconate dehydrogenase to drive the secondary reaction to completion or (b) inhibition of endogenous phosphogluconate dehydrogenase by 2,3-diphosphoglycerate. The present method has the advantages that reaction rate more quickly becomes linear and reagent cost is less as compared with other methods. The within-run coefficient of variation was 3%. The various methods investigated showed good statistical correlation.

Erythrocytes

[Timing of a letal intracranial hemorrhage by means of the HbA/HbF ratio (author's transl)].

Possibilities and limits of the method for timing an intracranial hemorrhage by means of the HbA/HbF erythrocyte ratio are investigated in six newborns. The effect of labeling HbF erythrocyte containing newborn blood by transfusion and exchange transfusion of HbA erythrocyte containing donor blood as well as "self-labeling" after the first transfusion as a result of HbA--and HbF erythrocytes decaying at a different rate, is described. If a coagulum can be clearly allocated to the blood where it originates from, depends a) on the alteration of the HbA/HbF erythrocyte ratio by the above mentioned ways of labeling and b) on the size of the sample i.e. on the number of erythrocytes counted to determine the HbA/HbF erythrocyte ratio. The confidence limits of the HbA/HbF erythrocyte ratio for a given number of counted erythrocytes have been determined. It was taken into account whether the blood was labelled by a transfusion or by "self-labeling". The analysis of the period before, during and after the intracranial hemorrhage made a preliminary evaluation of etiological factors and some symptoms possible. The hypothesis that sodium bicarbonate dosages of 8 mEqu/kg/24 h are an important cause of intracranial hemorrhage has to be rejected on the grounds of this study's results.

Cerebral Hemorrhage

[Respiratory therapy in childhood asthma. Part 2. Eutonic training].

Children with obstruction mainly due to spasms of bronchial smooth muscle will benefit most from breathing exercises. Attainment of the individual physiological balance of muscular, nervous and psychogenic tensions--the eutonic tension--is of great importance for control of regular unhurried breathing. This will be supported by stimulation of nasal breathing which increases diaphragmatic excursion. The eutonic state is the fundamental basis for success of chest rotations and rhythmic movements to stimulate further relaxation. Awareness of the fact that breaths come by themselves -- "automatically" -- reduces anxiety of shortness of breath. Observations of a group of asthmatic children in a summer camp support this form of treatment of asthma.

Asthma