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61.
Parallel to the inactivation of the X chromosome in somatic cells of female, the male X in mammals is rendered inactive during spermatogenesis. Pseudoautosomal genes, those present on the X-Y meiotically pairable region of male, escape inactivation in female soma. It is suggested, but not demonstrated, that they may also be refractory to the inactivation signal in male germ cells. We have assayed activity of the enzyme steroid sulfatase, product of a pseudoautosomal gene, in testicular cells of the mouse and shown its presence in premeiotic, meiotic (pachytene), and postmeiotic (spermatid) cell types. It appears that, as in females, pseudoautosomal genes may escape inactivation in male germ cells also. 相似文献
62.
Amita Gupta Raksha Arora Sanjay Gupta Bhupesh K Prusty Uma Kailash Swaraj Batra Bhudev C Das 《Journal of clinical virology》2006,37(3):190-194
Infection of specific types of high-risk human papillomaviruses (HPVs) causes cervical cancer in women. Conventional test for genital HPV infection requires collection of scraped cervical cells or biopsy specimens, which involves invasive procedures. Utility of non-invasive urine sampling for detection of HPV in women and their male sexual partners is controversial. The validation of this urine-based HPV DNA test is of immense value not only in screening large population and children but also for HPV vaccine monitoring in adolescents. We examined the frequency of high risk HPV types 16 and 18 in simultaneously collected urine samples and cervical scrapes or biopsy specimens from women with cervical cancer and their single lifetime male sexual partners in order to validate the utility of urine sampling as a reliable non-invasive method for detection of genital HPV infection. Thirty women with invasive cervical cancer and their husbands along with 30 age-matched normal healthy women including their husbands were recruited for the study. Cervical biopsies/scrapes from women subjects and penile scrapes from their husbands and urine samples from all of them were collected before taking biopsy or scrapes. HPV-L1 consensus primer as well as high-risk HPV (HPV 16 and 18) type-specific oligo-primers were used for PCR detection of HPV DNA. The total frequency of HPV in women with cervical cancer was found to be 83% (25/30) while it was only 67% (20/30) in their male partners but there was virtually no difference in results between urine and scrape or tissue biopsy either in women or their male partners. Although healthy women and their husbands showed similar frequency of HPV infection both in urine and scrape samples, there was a significant difference (p=0.05) in the prevalence of high risk HPV type 16 in women with cervical cancer (70%) and their male partners (30%). Similar was the trend between control women and their male partners. The results also showed a very high prevalence of HPV type 16 among Indian women with cervical cancer while its frequency was significantly low in their single lifetime male partners. The case by case matching of HPV positivity and negativity between urine and cervical/penile scrapes or biopsies obtained from women and their male partners demonstrated that the non-invasive urine sampling can be reliably used for screening genital HPV infection in both men and women. 相似文献
63.
Pelin Sahlén Rapolas Spalinskas Samina Asad Kunal Das Mahapatra Pontus Höjer Anandashankar Anil Jesper Eisfeldt Ankit Srivastava Pernilla Nikamo Anaya Mukherjee Kyu-Han Kim Otto Bergman Mona Ståhle Enikö Sonkoly Andor Pivarcsi Carl-Fredrik Wahlgren Magnus Nordenskjöld Fulya Taylan Isabel Tapia-Páez 《The Journal of allergy and clinical immunology》2021,147(5):1742-1752
64.
65.
Algorithms such as convolution superposition, Batho, and equivalent pathlength which were originally developed and validated for conventional treatments under conditions of electronic equilibrium using relatively large fields greater than 5 x 5 cm2 are routinely employed for inhomogeneity corrections. Modern day treatments using intensity modulated radiation therapy employ small beamlets characterized by the resolution of the multileaf collimator. These beamlets, in general, do not provide electronic equilibrium even in a homogeneous medium, and these effects are exaggerated in media with inhomogenieties. Monte Carlo simulations are becoming a tool of choice in understanding the dosimetry of small photon fields as they encounter low density media. In this study, depth dose data from the Monte Carlo simulations are compared to the results of the convolution superposition, Batho, and equivalent pathlength algorithms. The central axis dose within the low-density inhomogeneity as calculated by Monte Carlo simulation and convolution superposition decreases for small field sizes whereas it increases using the Batho and equivalent pathlength algorithms. The dose perturbation factor (DPF) is defined as the ratio of dose to a point within the inhomogeneity to the same point in a homogeneous phantom. The dose correction factor is defined as the ratio of dose calculated by an algorithm at a point to the Monte Carlo derived dose at the same point, respectively. DPF is noted to be significant for small fields and low density for all algorithms. Comparisons of the algorithms with Monte Carlo simulations is reflected in the DCF, which is close to 1.0 for the convolution-superposition algorithm. The Batho and equivalent pathlength algorithms differ significantly from Monte Carlo simulation for most field sizes and densities. Convolution superposition shows better agreement with Monte Carlo data versus the Batho or equivalent pathlength corrections. As the field size increases the DCF's for all algorithms converge toward 1.0. The largest differences in DCF are at the interface where changes in electron transport are greatest. For a 6 MV photon beam, electronic equilibrium is restored at field sizes above 3 cm diameter and all of the algorithms predict dose in and beyond the inhomogeneous region equally well. For accurate dosimetry of small fields within and near inhomogeneities, however, simple algorithms such as Batho and equivalent pathlength should be avoided. 相似文献
66.
67.
68.
PodurI CD Khanna A Khundmiri SJ Khaja MN Kumar KS Sugunan VS Habibullah CM Das MR 《Acta virologica》2001,45(1):1-6
The antibody profile to various proteins of hepatitis C virus (HCV) was studied in 113 patients positive for HCV RNA in various disease statuses of hepatitis C (HC). A single peptide (E2/NS1, aa 413-436 of HCV polyprotein) chosen from a conserved region at the C-terminus of the hypervariable region (HVR) HVR1 of HCV was found to be sufficient for reliable diagnosis of the infection, even in the acute phase. Six hundred and one suspected HC cases and 200 voluntary blood donors were tested by this peptide. The sensitivity of detection of HCV antibodies by this peptide did not increase with addition of peptides from other HCV proteins. Our results clearly demonstrate that antibodies to HCV envelope proteins occur in a higher percentage of the infected population than those to other proteins. This emphasizes the necessity of using representative sequences from HCV envelope proteins in diagnostic immunoassays of this viral infection. 相似文献
69.
K A Elias A K Das D Pardue C B Coulam J K Critser E S Critser 《American journal of reproductive immunology (New York, N.Y. : 1989)》1989,21(3-4):82-86
Published reports of pregnancy associated thrombocytopenia in mice have utilized the Quackenbush strain. The inability of some laboratories to verify this observation in other mouse strains prompted us to report our findings by using Swiss Albino ICR mice. In Exp. 1, pregnant and pseudopregnant mice were bled prior to mating (time 0) and daily on day 1 (vaginal plug) through day 7. In Exp. 2, media from 24 hr cultures of 2-cell mouse embryos or media from unfertilized oocytes were injected into splenectomized mice. Animals were bled at time 0 (before injection) and at 30, 60, and 120 min after injection. In Exp. 3, splenectomized mice were treated with either media from 2-cell stage embryos or with media supplemented with synthetic platelet-activating factor (PAF: 0.05, 0.1 or 0.2 micrograms). Animals were bled as in Exp. 2. Platelet numbers were determined in duplicate from each blood sample by using a hemacytometer. In Exp. 4, antagonist (SRI 63-441) or vehicle was administered to mated mice on days 1 through 4 of pregnancy. Animals were examined on day 8 to determine number of developing conceptuses. In Exp. 1-3, data were analyzed by using ANOVA for repeated measures, and in Exp. 4 data were analyzed by chi-square analysis. In Exp. 1, there was a treatment x time interaction (P less than .06) due to transient thrombocytopenia in pregnant but not pseudopregnant mice.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
70.
Establishment of a human hepatocellular carcinoma cell line releasing hepatitis B virus surface antigen 总被引:4,自引:0,他引:4
P K Das N C Nayak K N Tsiquaye A J Zuckerman 《British journal of experimental pathology》1980,61(6):648-654
A new hepatocellular carcinoma cell line, DELSH-5, derived from operative wedge biospy from a HBsAg sero- and tissue-positive patient, has been continuously propagated in vitro for nearly 22 months. The cells not only resemble hepatocytes on light and electron microscopic examination but also possess biosynthetic markers of the latter such as albumin and alpha-foetoprotein which were demonstrated in the supernatant medium as well as in the tumour cell cytoplasm. Karyology of cloned cells shows moderate aneuploidy, the major model chromosome number being 61. Though in the initial few passages HBsAg could not be detected, from the 13th passage onwards this viral component could be consistently demonstrated in small amounts in the concentrated supernatant medium by the macro- and micro-ELISA techniques. The immunohistochemical techniques as well as electron microscopy have failed to demonstrate any virus component inside the cell. The cell line reported here is the third of its kind which will act as a useful laboratory model to obtain pure HBsAg and to study the hepatitis-B-virus--liver-cell interaction with particular reference to the oncogenic potential of the virus. 相似文献