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HIV protease, an essential enzyme for viral particle maturation, is an important drug target of HIV. Its structural conformation is a key determinant of both biological function as well as efficient binding of protease inhibitor molecules. In the present study we analyzed 471 crystal structures of HIV-1 protease to understand the conformational changes induced by mutations or binding of various ligands and substrates. We performed principal component analysis on the ensembles of the HIV-1 protease structures to explore the conformational landscapes. The study identified structural differences between drug resistant and drug sensitive protease structures. Conformational changes were identified in the A and B chains of homo-dimeric HIV protease structures having different combinations of mutations, and also rigidity in the binding conformation of HIV drugs within the active site of the protein.© 2018 Wiley Periodicals, Inc.

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Initiation of the Tuberculosis Structural Consortium has resulted in the expansion of the Mycobacterium tuberculosis (MTB) protein structural database. Currently, 969 experimentally solved structures are available for 354 MTB proteins. This includes multiple crystal structures for a given protein under different functional conditions, such as the presence of different ligands or mutations. In depth analysis of the multiple structures reveal that subtle differences exist in conformations of a given protein under varied conditions. Therefore, it is immensely important to understand the conformational differences between the multiple structures of a given protein in order to select the most suitable structure for molecular docking and structure-based drug designing. Here, we introduce a web portal ( http://bmi.icmr.org.in/mtbsd/torsion.php ) that we developed to provide comparative data on the ensemble of available structures of MTB proteins, such as Cα root means square deviation (RMSD), sequence identity, presence of mutations and torsion angles. Additionally, torsion angles were used to perform principal component analysis (PCA) to identify the conformational differences between the structures. Additionally, we present a few case studies to demonstrate this database. Graphical Abstract Conformational changes seen in the structures of the enoyl-ACP reductase protein encoded by the Mycobacterial gene inhA.

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The effect of single intramuscular injection of 15(S)15 methyl PGF2α . (Prostin 15M, Upjohn) on cervical dilatation was tried in women during first trimester pregnancy. Prostin 15M was given at a dose of 250 µg. Three hours later the cervical dilatation and uterine consistency were assessed and recorded, prior to vacuum aspiration. The control group consisted of women who did not receive any drugs for cervical dilatation. The mean cervical dilatation in Prostin 15M group was 9.7 ± 2.3 (S.D.) mm compared to 3.4 ± 1.5 (S.D.) mm in the control group. This difference was statistically significant (p <0.01). Vomiting was experienced by 18.6% and diarrhea by 20.9% of the patients. There was no significant difference in the blood loss between the Prostin 15M group and the control group.

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A multicentre study was undertaken to study intramuscular 15(S)15 methyl PGF2α (Prostin 15M, Upjohn) for induction of second trimester abortion. The patients were premedicated with Imodium and Perinorm to control the gastrointestinal side effects. The dose of Prostin 15M was 250 µg every two hours and the progress of the abortion was assessed before each injection. If there was no progress at the end of 10 injections the case was classified as a failure. Ninety-seven patients were recruited for the study, 39 were primigravidae and 58 multigravidae. Twenty-four out of 39 primigravidae and 52 out of 58 multigravidae aborted with the treatment. The mean induction abortion interval was 17.8 hours in the primigravidae and 14.5 hours in the multigravidae patients. The mean number of episodes of vomiting was 2.9 and diarrhoea 4.2 per patient per trial. The primigravidae had slightly higher incidence of gastrointestinal side effects. The overall incidence of incomplete abortion was 17.1%.

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PIP: The efficacy, incidence of side effects, and discontinuation were studied in 50 subjects who received intramuscular norethisterone enanthate (200 mg) in 2 treatment schedules over an 18 month period. Subjects in group A received the injection every 2 months during the study period whereas those in group B received the injection at a 2 month interval for the 1st 6 months and every 3 months thereafter for 18 months. No pregnancy occurred in either group. Longer cycles and a higher incidence of amenorrhea were noted in the group B subjects. The bleeding pattern showed an increase in spotting episodes in group A at the 4th injection, following which no apparent difference in the bleeding pattern was noted in the 2 groups. The discontinuation rate was 80% at the end of the study, 28% of the subjects having dropped out for amenorrhea, 16% for irregular bleeding, and spotting, and 6% for minor medical complaints.^ieng

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In a trial of 71 women, 15(S) 15 methyl PGF2 alpha was administered intravenously at the dose level of 1 microgram/min for termination of pregnancy of between 11 weeks and 20 weeks of gestation. Sixty-one subjects (85.9%) aborted within 30 h of administration of the drug. The mean induction abortion interval was 15.65 h. The mean number of episodes of vomiting and diarrhea was 0.9 and 0.6, respectively. The effectiveness of the method is comparable to that of intramuscular method of administration, but the side effects are much less in comparison.

PIP: A group of 71 women between 11-20 weeks of gestation who desired termination of pregnancy and had no contraindications for prostaglandin (PG) administration were given complete physical and gynecological examinations; hemoglobin was estimated and urinalysis was done. They were then given orally 2 tablets of Lomotil (diphenoxylate HCl 2.5 mg + atropine sulphate 0.025 mg) and 1 tablet of Stemetil (Prochlorperazine 5 mg). They were then given 15 (S) 15 methyl PGF2alpha intravenously at the dose level of 1 mcg/min. 61 subjects (85.9%) aborted within 30 hours. At regular intervals pulse rate, blood pressure, uterine pain, nausea, vomiting, diarrhea, temperature, and respiratory rate were measured and any other side effects were recorded. The mean induction abortion interval was 15.65 hours, the mean number of episodes of vomiting and diarrhea was 0.9 and 0.6 respectively. This study compared well with the intramuscular route of administration with a higher rate of complete abortions and lower rate of side effects. The latter is explained on the basis of smaller amounts of the drug being infused at a slower rate. Disadvantages include confinement to bed, discomfort, and need of constant supervision. Compared with intraamniotic and extraamniotic case studies, the latter are invasive procedures while the intravenous method is not. Also, the intravenous route allows for adjusted drug dosage and stopping the procedure in the event of an undesirable reaction.

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Immunosuppressive properties of human chorionic gonadotropin (HCG), pregnancy specific B1-glycoprotein (SP-1), human alpha foetoprotein (AFP), and human placental lactogen (HPL) in mitogen-stimulated lymphocyte transformation were studied. A pregnancy serum containing high serum levels of these specific proteins was prepared from a number of pregnancy sera. The inhibitory effect of pregnancy sera on lymphocyte response to mitogen was examined after sequential removal of each of the proteins from the pregnancy serum by affinity chromatography. Greatest decrease in the suppression was observed when human chorionic gonadotropin (HCG) alone or human chorionic gonadotropin in combination with all other three specific proteins was removed from the pregnancy serum. Pregnancy specific B1-glycoprotein (SP-1) also significantly decreased the inhibitory effect of pregnancy serum. But the other two specific proteins (AFP and HPL) had minimal effect on the decrease an immunosuppression by pregnancy serum. However, even after removal of all the four pregnancy specific proteins from the pregnancy serum, complete return to normal values for lymphocyte transformation by mitogen was not observed, which indicates the presence of some other suppressive factor(s) in the pregnancy serum.

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Five fractions of human seminal plasma were isolated on Sephadex G-100 column. The in vitro effect of whole human seminal plasma and its fractions on the lymphocyte transformation induced by phytomitogen was studied. A significant inhibition of lymphocyte response to mitogen was observed with whole seminal plasma fractions I and III at a concentration of 100-200 micrograms/ml. However fraction II stimulates the in vitro human lymphocyte transformation induced by phytomitogen at a concentration of 200 micrograms/ml. Maximum amount of inhibition by whole seminal plasma and its fractions I and III was achieved by preexposure of lymphocytes to these antigens. Pre-exposure of lymphocytes to these antigens, followed by washing, does not result in suppression of lymphocyte response to mitogen. These observations suggest that the antigens of the whole seminal plasma or of fractions I, III, and II act by simple competition with mitogen for the receptor sites on the lymphocyte membrane. Therefore, the human seminal plasma may play an immunoregulatory role against the auto- or isosensitization towards spermatozoal antigens.

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The accuracy of placental localisation by radioisotopic scanning using 99mTc-labelled red blood cells has been estimated in 20 patients. The results have been correlated with the findings at delivery by direct and indirect methods. The accuracy of results regarding upper and lower segment insertion of the placenta was 90% in the present study.

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