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Biomedical subjects

M Cojocaru

Publications and source records attributed to M Cojocaru.

At least 37 records · Page 2Linked to original sources
PubMed1989

Accumulation of alpha-Tocopherol in Senescing Organs as Related to Chlorophyll Degradation.

alpha-Tocopherol (alpha-T) has been identified, using gas chromatography-mass spectroscopy and (1)H- and (13)C-nuclear magnetic resonance, in senescing leaves of Melia azedarach L. The content of alpha-T increased concomitantly with the breakdown of chlorophyll in senescing Vinca and Melia leaves. An increase in alpha-T was found also in detached Melia leaves, senescing in either light or darkness and in senescing, ethylene-treated orange leaves and fruit. The possibility that phytol, which is released from chlorophyll by chlorophyllase is utilized for the biosynthesis of alpha-T is discussed. Senescing leaves of the low chlorophyllase plants, parsley and tobacco, did not contain alpha-T in measureable amounts.

Journal Article↗
PubMed1989

[The drawing of blood for performing routine and complementary immunological studies in medical practice].

Here is shown that drawing blood for immunological tests represents an important stage that must be reached according to medical indications, in order to avoid errors, taking into account the large range of these tests. All along the report it is discussed the dividing of the immunological tests needed into usual ones, with a value of basis screening, and complementary tests, with a value of advanced screening and their detailing. With regards to the immunopathological substratum, it is always necessary that the immunological tests should be performed by medical staff specialized in this domain.

Bloodletting↗
PubMed1989

[Research on phagocytosis].

A problem of particular importance, but also particularly difficult, is the investigation of the phagocytic system, considering its implication in various aspects of pathology. This has determined the authors to present the major modalities for the investigation of phagocytosis. They recommend as a diagnostic method for garnulocytopathies (including a series of metabolic abnormalities. Of the leucocytes with implications for the bactericidal capacity), a testing of leucocyte bactericidal capacity. The test with nitroblue tetrazolium is also recommended, for the screening and differential diagnosis of fever conditions of infectious origin and other etiologies.

Humans↗
PubMed1988

Preparation of 3 beta, 5 alpha-, 3 alpha, 5 alpha- and 3 alpha, 5 beta-tetrahydro derivatives of 19-noraldosterone by chemical synthesis and microbial bioconversion.

The 3 beta, 5 alpha-, 3 alpha, 5 alpha- and 3 alpha, 5 beta-tetrahydro derivatives 19, 20 and 27 of 19-noraldosterone (1) were prepared to facilitate the search for these compounds in urine. The diketal 4, consisting of a 2:1 mixture of the 5,6- and 5(10)-ene isomers, was hydrogenated with Pd-C and partially hydrolyzed to 5 alpha, 10 alpha- and 5 alpha, 10 beta-dihydroketals 8 and 10 in a 1:2.5 ratio. Assignment of protons was done with aid of COSY 45 experiments. Compound 10 was reduced with diisobutylaluminum hydride (DIBAH) to 4 products: the 3 alpha- and 3 beta-ol hemiacetals 16 and 15, and the corresponding tetraols 14 and 13. Alternatively, hydrogenation of the 4-en-3-one 2 gave 10, its 5 beta, 10 beta-isomer 21 and the tetrahydro compound 22, in a 4:2:1 ratio. A better way to prepare the 5 beta, 10 beta-series involved microbial conversion of 2 with Clostridium paraputrificum, and the resulting tetrahydrolactone 23 was reduced with DIBAH to the hemiacetal 24. Acid hydrolysis of 16, 15 and 24 afforded 20, 19 and 27, respectively. According to [1H]-NMR, in solution 20 and 24 exist as mixtures of isomers, while 19 appears in one form only. Periodate oxidation converted 19 and 27 into their gamma-etiolactones 18 and 28. EI MS base peaks are different and characteristic for 19, 20 and 27.

Aldosterone↗
PubMed1987

The intrinsic synthesis of juvenile hormone-III diol by locust corpora allata in vitro.

Juvenile hormone (JH)-III 10-11-diol is intrinsically synthesized and released from the corpora allata (CA) of adult locust females in vitro, together with JH-III. JH-III synthesis is preferentially stimulated and diol production only slightly enhanced, by cerebral locust allatotropin. The identification of JH-III diol is based on: similar ratio of incorporation of 14C/3H from radiolabelled [2-14C]acetate and [methyl-3H]methionine, to that of JH-III; similar chromatographic properties to those of synthetic diol on an RP-18 column eluted with acetonitrile, and similar chromatographic properties of acetylated derivatives; mass spectrometric analysis of derivatives and fragmentation products. Exogenous radiolabelled JH-III is not degraded during incubation with locust CA in vitro, corroborating the endogenous production of JH-III diol. Allatal diol formation may be an additional mechanism for the control of JH-III levels in locusts, preceding release into the hemolymph.

Animals↗
PubMed1986

Synthesis of 19-noraldosterone, a potent mineralocorticoid.

19-Noraldosterone has been prepared for biological re-evaluation through an extension of a recent synthesis of 19-hydroxyaldosterone: 21-hydroxy-6 beta,19-epoxy-4-pregnene-3,20-dion-20-ethylene ketal-18,11 beta-lactone (1a) was acetylated and then reduced with zinc-acetic acid-isopropanol to the 19-ol 2b. Treatment with sodium acetate transposed the double bond into conjugation, and 2a thus obtained was oxidized with pyridinium chlorochromate to the 19-oxo compound 3. Decarbonylation to the 19-nor lactone 4 was effected by heating with alkali. Protection of the C-3 carbonyl was achieved by ketalization and the resulting mixture of the 5-ene and 5(10)-ene ketals 5 was reduced with DIBAH to the corresponding mixture of the hemiacetals 6. Acid hydrolysis of the latter afforded 19-noraldosterone (7), accompanied by the 18,21-anhydro ketal 8. 19-Noraldosterone in the solid state exists in the cyclic form 7b, which appears to be also the predominant isomer present under conditions of mass spectrometry. [1H]NMR indicates that in chloroform 19-noraldosterone exists mostly as an equilibrium mixture of structures 7a and 7b. Sodium periodate oxidation furnished the gamma-etiolactone 9, confirming the 17 beta configuration in 7.

Aldosterone↗
PubMed1986

Synthesis of 18-hydroxy-19-norcorticosterone and 18-deoxy-19-noraldosterone. Structure determination of related 19-nor steroids by means of 2-D 1H nmr.

The compounds named in the title have been synthesized from the di-(ethylene ketal) of 21-hydroxy-3,20-dioxo-19-norpregn-5-ene-18, 11 beta-lactone and its 5(10)-ene isomer. Reduction of this mixture 1 with sodium aluminum bis-(methoxyethoxy)hydride furnished the 11 beta, 18, 21-triol 2a. Conversion to the 18,21-diacetate 2b, followed by deketalization to the free dione 3 and hydrolysis, afforded 18-hydroxy-19-norcorticosterone 4a which, in the solid state and probably in solution, has the 18,20-hemiacetal structure. Periodate oxidation of 4a gave 11 beta-hydroxy-3-oxo-19-norandrost-4-ene-17 beta, 18-carbolactone 5a, and acid treatment of 4a or its precursor 2a yielded 18-deoxy-19-noraldosterone 6a. The structure of 5a was confirmed by mass spectrometry and 1H nmr, and compared with that of its C-19 methyl homolog 5b and 19-noraldosterone-gamma-etiolactone 8. In particular, 2-D nmr COSY 45 experiments, affording full 1H line assignments, have rigorously established the "natural" beta (axial) configuration of the C-10 hydrogen in the 19-nor lactones 5a and 8, and therefore also in the related 4a, 6a and 19-noraldosterone 7.

18-Hydroxycorticosterone↗
PubMedDate not supplied

Synthesis of 18,19-dihydroxycorticosterone.

A four-step synthesis of 18,19-dihydroxycorticosterone 5c, starting with 19,21-dihydroxy-3,20-dioxopregn-5-ene-18,11 beta-lactone-di-(ethylene ketal) 2, is presented. Reduction of 2 with sodium aluminum bis-(methoxyethoxy)hydride gave 11 beta,18,19,21-tetrahydroxy-pregn-5-ene-3,20-dione-di-(ethylene ketal) 3a. Acetylation furnished the corresponding 18,19,21-triacetate 3b, which on treatment with a mixture of perchloric and acetic acids gave 18,19-dihydroxycorticosterone 18,19,21-triacetate 4b. Mild saponification yielded the title compound which, on the basis of ir and nmr spectra, exists as one C-20 isomer of the hemiacetal structure 5c. Periodate oxidation of 5c gave the expected 11 beta, 19-dihydroxy-3-oxoandrost-4-ene-17 beta, 18-carbolactone 6b.

18-Hydroxycorticosterone↗
PubMedDate not supplied

Value of the lymphoblastic transformation in patients with silicosis.

The authors verify whether in silicosis the accumulation of silicon dioxide (SiO2) particles in the lung can induce changes of the activated T lymphocytes in the peripheral blood. The lymphoblastic transformation of lymphocytes stimulated with phytohemagglutinin (PHA), concanavalin A (Con A), Mycobacterium tuberculosis (Mt) and purified protein derivative (PPD) was studied using the classical methods. It was observed that in patients exposed to SiO2 lymphocyte reactivity to the above stimulants decreases. Significant differences between patients and controls were observed only in the response to PHA (p < 0.001).

Humans↗
PubMedDate not supplied

Considerations on the changes of certain immunologic parameters in occupational allergic bronchial asthma due to textile fibers.

The changes of some immunologic parameters such as IgG, IgA and IgM, the C3 complement, the circulating immune complexes and alpha 1--antitrypsin were investigated in 75 patients with occupational allergic bronchial asthma to textile fibers as compared with 50 apparently healthy controls with no occupational exposure to textile fibers. It was observed that IgG and IgA decreased significantly while IgM increased. Likewise C3 decreased in all patients with occupational allergic bronchial asthma (OABA) as compared with the controls an CIC increased significantly. The determinations carried out demonstrated a parallelism of action in the immune response.

Adult↗
PubMedDate not supplied

[Antilipemic therapy in dyslipidemias in obese non-insulin-dependent diabetics (ONIDDM)].

There are multiple lipids anomalies on diabetes. IDDM has, because of insulin lack, raised levels of triglycerides and afferent lipoproteins. NIDDM, especially the obese one, directly linked with insulin-resistance and hyperinsulinemia, has different and complex anomalies. There is a specific type named "B phenotype" with high cardiovascular risk: raised LDL chol charged with TG and low level of HDL chol. Our study on 58 cases with NIDDM obese concluded that only 28% had high TG levels but 71.8% had low levels of HDL chol. We administered fibrates, therapeutical doses, 3 months. We made lipidograms from the beginning and after one and three months. So we proved the good effect of fibrates on lipids: rise of HDL chol., moderate effect on LDL chol. for reduced cardio-vascular risk. There were good results on glucose tolerability (improving 65.8%, p < 0.01).

Adult↗
PubMedDate not supplied

Peripheral leukocytes activation in aortic aneurysmal disease.

The pathogenesis of aneurysmal disease involves factors acting over time. A sustained chronic inflammatory reaction is observed in association with initiations, maintenance, rapid growth and rupture of aortic aneurysms. This study was designed to identify the possible pathogenic role of the inflammatory cells in the outcome of aneurysmal disease, testing the activation state of peripheral lymphocytes and neutrophils. Circulating activated lymphocytes and repeated peaks of neutrophils activation in sequential follow-up is associated with larger aneurysms, mural thrombosis, tendency to aneurysm extension and rupture.

Aged↗
PubMedDate not supplied

Study of islet cell antibodies as predictive marker of type 1 diabetes.

The aim of this study was to evidence whether islet cell antibodies (ICAs) (by a standard indirect immunofluorescent technique) could be used to identify subjects at risk for type-1 diabetes. In the present prospective diabetes family study, 23 of 2642 first-degree relatives of patients with type-1 diabetes have developed the disease. The antibody status of these 23 samples was compared with that from 23 carefully matched control. At a mean of 26 years before the onset of diabetes, ICAs were found in 16 patients at the titer 1:60 (versus O control subjects, p < 0.001). The authors consider that ICAs may be interpreted as an immunological change in the islets of first-degree relatives of patients with type-1 diabetes.

Autoantibodies↗
PubMedDate not supplied

Considerations on the changes of certain immunologic cells in silicosis.

Cell-mediated immunity was estimated in a group of 68 patients divided into three subgroups according to the evolutive stage of disease. It was demonstrated that in silicosis there is a disturbance of immunity. The detection of E rosettes and of activated rosettes was carried out according to the classical method. The mean percentage of total T lymphocytes was found lower in silicosis (62 +/- 2% statistically significant for p < 0.05), compared to the control group (66 +/- 4.6%). The study revealed a decrease of T helper lymphocytes, an increase of T suppressor/cytotoxic lymphocytes and a decrease of the T helper/T suppressor ratio (1.96 +/- 0.13) in silicosis as compared to the control group (2.83 +/- 0.31). The presence of these changes in silicotic patients suggested the participation of cell-mediated immunity in the pathogenesis of disease, the cell mediated immunity being directly responsible for the evolution of silicosis.

Adult↗
PubMedDate not supplied

Changes of circulating immune complexes in the serum and CSF of patients with multiple sclerosis.

The level of circulating immune complexes (CIC) was studied before and after treatment in a group of 86 patients with multiple sclerosis (MS) (36 males and 50 females) ranging in age between 20 and 30 years and in 32 controls. CIC determinations were performed both in the serum and in the CSF, using the method of precipitation in polyethylene glycol (PEG). In 61.62% of the patients the mean serum CIC values (82.44 ODU; p = 0.01) exceeded those found in the controls (60.1 ODU) while the CSF mean CIC values (21.63 ODU; p = 0.05) exceeded those in the controls in 59.30% of the patients (12.8 ODU). The prevalence of patients with CIC values exceeding the control values presented variations according to the clinical stage of disease. Thus in the acute stage 83.33% of the patients presented the highest mean serum CIC values (110.5 ODU; p = 0.05) and 100% of the patients presented the highest mean CSF CIC values (27.9 ODU). After treatment it was observed that the prevalence of patients with high CIC values decreased. In conclusion it was observed that there is a correlation between the prevalence of patients with increased CIC values in the serum and CSF, and the clinical stage and treatment administered. This observation suggests that CIC determinations both in the serum and in the CSF may constitute an immunologic marker in MS.

Adult↗