Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 34
Filtrar
1.
J Chromatogr Sci ; 47(7): 529-33, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19772721

RESUMO

Ultra-trace analysis of azide in complicated Irbesartan sample matrix is achieved by the in-line sample preparation technique. Sodium azide is the precursor of Irbesartan, which is used as an anti-hypertensive drug. Due to the toxic nature of sodium azide, reliable determination of azide in Irbesartan is necessary. Irbesartan when analyzed for sodium azide, as per the USP 31-NF26 method, gets adsorbed to the analytical column, leading to reduction in column capacity and irreproducible retention time. The retained drug has to be removed with special rinsing solution, followed by re-equilibration with the mobile phase. This process takes at least 3 to 4 h for each sample analysis. The new method developed overcomes the limitations of the USP 31-NF26 method. This method is validated for specificity, linearity, accuracy, precision, sample solution stability, and robustness as per International Conference on Harmonization guidelines. The relationship between peak response and concentration is found to be linear between 5 to 80 ng/mL of sodium azide, with the correlation coefficient (r(2)) of 0.9995. The limits of detection and quantification for sodium azide are 0.532 and 1.61 microg/gm with respect to the sample weight.


Assuntos
Azidas/análise , Compostos de Bifenilo/análise , Tetrazóis/análise , Química Farmacêutica/métodos , Contaminação de Medicamentos , Irbesartana , Reprodutibilidade dos Testes , Incerteza
2.
Cancer Res ; 49(21): 6098-107, 1989 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-2790823

RESUMO

The squamous cell carcinoma (SCC) cell lines UM-SCC-17A and -17B were derived, respectively, from the primary laryngeal cancer and a metastatic neck tumor of a patient who failed to respond to radiation therapy but achieved long-term remission after surgery. The karyotypes of both cell lines and a subline of 17A were pseudodiploid and stable in multiple in vitro passages. Several karyotypic abnormalities were common to all three cell lines and therefore represent mutations present in the tumor before the divergence of the metastatic and subline populations whereas those rearrangements observed only in one cell are more likely to be secondary. The shared mutations include: duplication of the short and proximal long arm of chromosome 2, isochromosome 3q, duplication 7, inversion 8, duplication of the distal long arm of 18, and monosomy 21 or ring 21. Each line had different rearrangements involving chromosome 7 that resulted in three copies of most of the short arm being present in both cell lines, except for high passages of 17B, in which one structurally normal 7 was replaced by a dicentric isochromosome, dic(7)(q11.22), resulting in four copies of 7p. The dic(7) may represent an in vitro mutation. An isochromosome 13q was noted in both the stemline and subline of UM-SCC-17A but not in UM-SCC-17B. A del(11p) and an iso(21q) were present only in the 17A subline. The cell lines expressed the membrane antigen phenotype characteristic of squamous cancers although the UM-SCC-17A subline differed with respect to three markers. Of these, the A9 and blood group antigen changes are thought to be associated with progression. The subline, which carried the del(11)(p13-p15.1), also failed to express the E7 antigen mapped to the band 11p13. It is possible that the two apparently normal 11s in this subline carry a point mutation or microscopically undetected deletion involving the E7 antigen locus.


Assuntos
Carcinoma de Células Escamosas/genética , Aberrações Cromossômicas , Neoplasias Laríngeas/genética , Antígenos de Neoplasias/análise , Antígenos de Superfície/análise , Carcinoma de Células Escamosas/patologia , Linhagem Celular , Inversão Cromossômica , Mapeamento Cromossômico , Humanos , Cariotipagem , Neoplasias Laríngeas/patologia , Metástase Neoplásica , Fenótipo , Translocação Genética
3.
Cancer Res ; 47(24 Pt 1): 6800-5, 1987 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-3479251

RESUMO

Tumor cells from direct harvests and short term cultures were karyotyped from 15 patients with transitional cell carcinoma of the bladder. There were two tumors with an apparently normal diploid karyotype, eight with counts up to 50 and with marker chromosomes, and five with counts of 60 or more and with markers. The median duration between recurrences was 3 months for the near-diploid, and 3 months for the near-polyploid tumors. One patient whose tumor was normal diploid had a recurrence at 5 months and the second patient whose tumor had normal diploid tumor had no recurrence over 15 months. Four tumors (27% of the series) had a rearrangement involving band 3p14: three had +der(5)t(3;5)(p14;p14) and one had +der(6)t(1;3;6)(q21;p14;p23). Duplication 3p14----3pter was observed in four tumors, and deletion 11p15----11pter in five. Three other abnormalities were observed in three cases each: deletion 5p14----5pter, duplication 1q23----1q32 and deletion 6q21----6qter. Trisomy 7 was observed as a sole clonal abnormality in one carcinoma in situ. Thirteen of 15 patients had recurrence of their tumor. Tumor progression (either in stage or grade) was evident in seven recurrent tumors. Among the seven with tumor progression, three had 11p deletion, two had 11p deletion plus 3p duplication, one had 3p duplication, and one had trisomy 7. Four of the five that had 11p deletion underwent cystectomy and three have died. Three of eight near-diploid tumors progressed and four of five near-tetraploid tumors progressed. It will be important to characterize any cytogenetic changes that are of prognostic value, since the categorization of bladder tumors by other methods has been problematic.


Assuntos
Carcinoma de Células de Transição/genética , Marcadores Genéticos , Neoplasias da Bexiga Urinária/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células de Transição/patologia , Deleção Cromossômica , Cromossomos Humanos Par 11 , Cromossomos Humanos Par 3 , Cromossomos Humanos Par 7 , Feminino , Humanos , Cariotipagem , Masculino , Pessoa de Meia-Idade , Trissomia , Neoplasias da Bexiga Urinária/patologia
4.
Cancer Res ; 48(7): 1864-73, 1988 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-3349465

RESUMO

The University of Michigan endometrial carcinoma cell line UM-EC-1 was derived from a poorly differentiated endometrial adenocarcinoma of a 66-yr-old white female. Cell cultures were started using both tumor explants and a cell suspension obtained from collagenase-treated tumor tissue. The collagenase-derived cell suspension gave rise to monolayer cultures which grew rapidly from the outset. This subline of UM-EC-1 has now been subcultured more than 50 times. Cells derived from the tumor explants grew more slowly initially, but after a lag phase of 5 to 6 wk, this subline also exhibited rapid logarithmic growth and reached the same growth rate as that of the collagenase-treated cells. The explant subline has been subcultured more than 37 times. The doubling time of both sublines is 24 h under optimal growth conditions. The karyotype of both cell cultures is 43, XX, inv(1)(p32q42), -4, +der(8) t(8;12)(p23.1;q22), del(9)(q11), -13, -13, +t(13;13) (p13;p13), del(18)(q), -19, -22, -22, +t(22;22)(p11;p11). The net result of the chromosome losses and rearrangements was monosomy 4, duplication 8p23.1----qter, deletion 9q11----9qter, duplication 12q22----qter, deletion 18q, and monosomy 19. The t(13;13) and the t(22;22) were dicentric by C-banding. Virtually all of the chromosome changes were stable in multiple passages except that there was mosaicism for chromosome 13. Some cells contained a single copy of 13 and others had t(13;13). The available evidence indicates the t(13;13) is an isochromosome. UM-EC-1 cells produced tumors histologically similar to the original tumor in male, female, and ovariectomized female athymic mice. UM-EC-1 cells express human class I histocompatibility antigens as assessed by binding of antibodies to nonpolymorphic HLA and beta-2-microglobulin antigens. Blood group antigens A and H were absent although the patient is blood type A and these antigens are normally expressed in endometrial glands. A rearrangement involving the region of chromosome nine that carries the ABH locus may be related to the absence of blood group antigen expression by these cells. The E7 membrane antigen, the locus for which resides on the short arm of chromosome 11, was expressed strongly which is consistent with the presence of two intact copies of chromosome 11 in these cells.


Assuntos
Carcinoma/patologia , Linhagem Celular , Neoplasias Uterinas/patologia , Aneuploidia , Animais , Antígenos de Neoplasias/análise , Antígenos de Superfície/análise , Carcinoma/genética , Diferenciação Celular , Divisão Celular , Núcleo Celular/ultraestrutura , Feminino , Humanos , Camundongos , Camundongos Nus , Transplante de Neoplasias , Cromossomos em Anel , Neoplasias Uterinas/genética
5.
Am J Med Genet ; 44(4): 437-8, 1992 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-1442883

RESUMO

We report on a liveborn premature male with trisomy 22 who had multiple congenital anomalies, including congenital diaphragmatic hernia and absence of corpus callosum. He died of pulmonary hypoplasia associated with diaphragmatic hernia within 12 hours of age. Chromosome analysis by multiple banding techniques based on lymphocyte culture confirmed that he had trisomy 22. This may be the first report of congenital diaphragmatic hernia and isolated absence of corpus callosum associated with trisomy 22.


Assuntos
Agenesia do Corpo Caloso , Cromossomos Humanos Par 22 , Hérnias Diafragmáticas Congênitas , Doenças do Prematuro/genética , Trissomia , Anormalidades Múltiplas/genética , Hérnia Diafragmática/diagnóstico por imagem , Hérnia Diafragmática/genética , Humanos , Recém-Nascido , Masculino , Radiografia
6.
Am J Med Genet ; 39(2): 130-2, 1991 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-2063913

RESUMO

We report on a mother and son with a 3p25-pter deletion. Both have postnatal growth retardation, mental retardation, apparently low-set or malformed ears, and telecanthus. The mother also has ptosis and multiple joint pains, while the son has a long philtrum and anteverted nares. These phenotypes are compared to those of other 3p- patients. Both patients have many manifestations previously described. The son appears to be more severely affected than the mother.


Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 3 , Anormalidades Múltiplas/genética , Adulto , Pré-Escolar , Feminino , Transtornos do Crescimento/genética , Humanos , Deficiência Intelectual/genética , Cariotipagem , Masculino
7.
Am J Med Genet ; 45(4): 447-9, 1993 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-8465848

RESUMO

We describe a 14-year-old boy with physical and behavioral manifestations of the Smith-Magenis syndrome. Low level mosaicism (11%) for deletion 17p11.2 was found in peripheral blood lymphocytes. The deletion was also observed in 100% of metaphases examined from skin fibroblast cultures. We confirm that the Smith-Magenis syndrome is associated with a highly recognizable phenotype. Because evidence of the abnormal cell line may be minimal or absent in peripheral blood, fibroblast studies are indicated for patients in whom mosaicism for deletion 17p11.2 is suspected clinically.


Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 17 , Mosaicismo , Adolescente , Células Cultivadas , Feminino , Humanos , Cariotipagem , Rim/anormalidades , Masculino , Pessoa de Meia-Idade , Comportamento Autodestrutivo/genética , Síndrome , Ureter/anormalidades
8.
Am J Med Genet ; 27(3): 739-48, 1987 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2888311

RESUMO

Multiple endocrine neoplasia (MEN) type 2A and 2B are autosomal dominant syndromes in which medullary thyroid cancers are associated with adrenal pheochromocytomas. We have expanded our double-blind studies of high-resolution G-banded chromosomes from lymphocytes to a total of 12 MEN-2A families, 7 MEN-2B (mucosal neuroma phenotype) families and 23 non-MEN control subjects. Eighteen of 23 different control subjects were scored as having normal chromosomes 20, and 15 of 21 MEN-2A and 4 of 8 MEN-2B patients were scored as having an interstitial deletion: del(20) (p12.2p12.2). These findings suggest that the dominant mutation in many MEN-2A and MEN-2B families is a visible deletion within band 20p12.2. Combining the results of these double-blind studies with those of the only other comparable reported double-blind series provides a statistical probability of less than 1/1000 that the association between MEN-2A and the deletion was observed by chance alone. However, the occasional discrepancies in classification using presently available techniques preclude the use of high resolution chromosome studies for the diagnosis of MEN-2.


Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 20/ultraestrutura , Neoplasia Endócrina Múltipla/genética , Método Duplo-Cego , Genes Dominantes , Ligação Genética , Marcadores Genéticos , Humanos , Cariotipagem
9.
Am J Med Genet ; 32(3): 320-4, 1989 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2729351

RESUMO

We report on two patients with mosaic tetrasomy of 8p[46,XY/47,XY,+i(8p)], a previously unreported cytogenetic anomaly. The first patient had a low percentage of tetrasomic (secondary trisomic) cells in lymphocytes and fibroblasts, an only mildly abnormal phenotype, and a rather benign clinical course. The second patient had a considerably larger percentage of tetrasomic cells in lymphocytes and fibroblasts, and had more severe congenital anomalies that led to his death at 8 months. A characteristic phenotype +i(8p) is suggested but not yet established. The manifestations of these two patients resemble those of mosaic trisomy 8 and mosaic trisomy 8p, with rib and vertebral abnormalities, absent corpus callosum, and enlarged cerebral ventricles.


Assuntos
Aberrações Cromossômicas/genética , Cromossomos Humanos Par 8 , Trissomia , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/patologia , Encéfalo/anormalidades , Criança , Aberrações Cromossômicas/patologia , Bandeamento Cromossômico , Transtornos Cromossômicos , Dermatoglifia , Humanos , Lactente , Cariotipagem , Imageamento por Ressonância Magnética , Masculino , Mosaicismo , Fenótipo
10.
Am J Med Genet ; 43(6): 996-1005, 1992 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-1415351

RESUMO

Since some patients with Ullrich-Turner syndrome (UTS) have mental retardation, we reviewed our experience to look for a high-risk subgroup. Among 190 UTS and gonadal dysgenesis patients with X chromosome abnormalities, 12 had mental retardation. All of the six (100%) with a small ring X were educable (EMI) or trainable mentally impaired (TMI) with more severe delay than expected in UTS. Among the 184 with other X abnormalities, only 6 had similar delays (2 from postnatal catastrophes), for a frequency of 3.3% mental retardation among those without a small ring X; only 2.2% of these had unexplained mental retardation. Polymerase chain reaction studies showed no Y-derived material in the 2 patients who were evaluated, and in situ hybridization confirmed X origin of the ring in the 6 subjects who were evaluated. We describe the phenotype of the 6 individuals with a small ring X, and an additional 2 patients with a small ring X who were identified outside the survey. The subjects with a small ring X comprised a clinically distinct subgroup which had EMI/TMI and shorter stature than expected in UTS. Seizures and a head circumference less than 10th centile were observed in half of the patients with a small ring X, and strabismus, epicanthus, and single palmar creases were present in more than half. A "triangular" face in childhood, pigmentary dysplasia, sacral dimple, and heart defects were also common. Neck webbing appeared to be less frequent than in 45,X. We hypothesize that the high risk of mental retardation in this form of the UTS results from lack of lyonization of the ring X due to loss of the X inactivation center. Excluding those with a small ring X, mental retardation is not significantly increased in patients with UTS.


Assuntos
Deficiência Intelectual/genética , Cromossomos em Anel , Síndrome de Turner/genética , Cromossomo X , Adolescente , Criança , Pré-Escolar , Mecanismo Genético de Compensação de Dose , Feminino , Humanos , Pessoa de Meia-Idade , Fenótipo , Síndrome de Turner/classificação
11.
Biosens Bioelectron ; 19(10): 1337-41, 2004 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-15046768

RESUMO

An important requirement of immobilized enzyme based biosensors is the thermal stability of the enzyme. Studies were carried out to increase thermal stability of glucose oxidase (GOD) for biosensor applications. Immobilization of the enzyme was carried out using glass beads as support and the effect of silane concentration (in the range 1-10%) during the silanization step on the thermal stability of GOD has been investigated. Upon incubation at 70 degrees C for 3h, the activity retention with 1% silane was only 23%, which increased with silane concentration to reach a maximum up to 250% of the initial activity with 4% silane. Above this concentration the activity decreased. The increased stability of the enzyme in the presence of high silane concentrations may be attributed to the increase in the surface hydrophobicity of the support. The decrease in the enzyme stability for silane concentrations above 4% was apparently due to the uneven deposition of the silane layer on the glass bead support. Further work on thermal stability above 70 degrees C was carried out by using 4% silane and it was found that the enzyme was stable up to 75 degrees C with an increased activity of 180% after 3-h incubation. Although silanization has been used for the modification of the supports for immobilization of enzymes, the use of higher concentrations to stabilize immobilized enzymes is being reported for the first time.


Assuntos
Técnicas Biossensoriais/instrumentação , Glucose Oxidase , Silanos , Estabilidade Enzimática , Temperatura Alta
12.
Cancer Genet Cytogenet ; 48(1): 83-7, 1990 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-2372791

RESUMO

We cytogenetically studied four cases of adenocarcinoma of the prostate. All tumors were moderately differentiated or well-differentiated, with different degrees of invasion. One tumor with microscopic seminal vesicle invasion and lymph node metastasis (tumor 4) had trisomy 7 as a sole clonal abnormality, suggesting that this is a primary change in some prostatic tumors. Although only normal karyotypes were observed in the other three tumors, several nonclonal changes were evident. Monosomy 9 or deletion of the long arm of 9 was observed in at least one cell in the three tumors without trisomy 7. Furthermore, in one of these tumors (tumor 3, moderately differentiated), several rearrangements (five of 26 cells) were observed, two of which had a common breakpoint at 15q11. Although complex chromosome changes including del(10q) and del(7q) have been described in prostatic tumors, they were not observed in the four tumors studied. This is the first report of a prostate tumor with trisomy 7 as a single clonal chromosome abnormality.


Assuntos
Adenocarcinoma/genética , Aberrações Cromossômicas , Neoplasias da Próstata/genética , Idoso , Idoso de 80 Anos ou mais , Bandeamento Cromossômico , Cromossomos Humanos Par 7 , Marcadores Genéticos , Humanos , Cariotipagem , Masculino , Pessoa de Meia-Idade , Trissomia
13.
Arch Pathol Lab Med ; 114(4): 426-9, 1990 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-2322103

RESUMO

A case of granulocytic sarcoma presenting as a soft-tissue tumor in the chest wall in a patient with osteomyelosclerosis is reported. The tumor mass was detected by a computed tomographic scan during an investigation of the cause of chest pain in a 58-year-old man. Biopsy of the mass showed findings compatible with either a large-cell lymphoma or a granulocytic sarcoma. The latter was confirmed by naphthol-ASD-chloracetate esterase stain and electron microscopic examination. Immunologic study of the tumor mass showed expressions of membrane/cytoplasmic CD 13 and CD 15 antigens. In addition, the tumor cells coexpressed CD 19, although all other T- and B-cell-associated antigens were absent. Cytogenetic study showed translocation t(1;7)(q11;q11) with a net deletion of the entire long arm of chromosome 7 and duplication of the long arm of chromosome 1. Peripheral blood examination showed typical leukoerythroblastosis with teardrop poikilocytosis, large hypogranular platelets, and 0.11 myeloblasts. A bilateral iliac bone marrow biopsy at this time showed osteomyelosclerosis. The patient was treated with hydroxyurea followed by local irradiation, resulting in marked reduction in the size of the tumor and in the pain. He was asymptomatic without any progression in hematologic parameters 10 months after the initial diagnosis.


Assuntos
Leucemia Mieloide/patologia , Osteomielite/patologia , Neoplasias Torácicas/patologia , Tórax/patologia , Humanos , Leucemia Mieloide/genética , Leucemia Mieloide/imunologia , Masculino , Pessoa de Meia-Idade , Osteomielite/genética , Osteomielite/imunologia , Esclerose , Neoplasias Torácicas/genética , Neoplasias Torácicas/imunologia
14.
Surg Neurol ; 40(3): 224-9, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8346476

RESUMO

Pituitary adenomas are the most common tumors of the sellar region and are, with rare exception, benign neoplasms. The natural history of these lesions is only poorly understood and, although histologic, immunocytologic, and ultrastructural characteristics have been well established, predicting the natural history of individual tumors is, at best, unreliable. In an effort to better characterize pituitary adenomas, we have analyzed the karyotypes of 18 surgical specimens and attempted to correlate with the morphologic appearance and the clinical data, for example, endocrinologic subtypes, histology, and tumor invasiveness. Most hormonal subtypes were studied including seven growth hormone-prolactin (GH-PRL), two Prolactin (PRL), two Adrenocorticotrophin (ACTH), seven nonsecretory (NULL). No correlations with morphology or invasiveness could be made. Of 7 null cell adenomas, five (71%) had normal karyotypes, whereas of 11 hormone-secreting adenomas three (28%) were normal. Of seven tumors with mixed GH-PRL activity, six had abnormal karyotypes. At least three chromosomes harbored abnormalities shared by more than two tumors. The results demonstrate that chromosome abnormalities are also found in benign tumors. These findings, however, suggest that hormone-secreting adenomas may be more likely to be associated with karyotypic abnormalities especially those of the GH-PRL variety. Genetic abnormalities associated with chromosomes 1, 4, 7, and 19 were common and warrant further investigation.


Assuntos
Adenoma/genética , Neoplasias Hipofisárias/genética , Adenoma/patologia , Adulto , Idoso , Feminino , Humanos , Cariotipagem , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Projetos Piloto , Neoplasias Hipofisárias/patologia , Células Tumorais Cultivadas
15.
Appl Biochem Biotechnol ; 166(1): 112-26, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22116671

RESUMO

We report for the first time the development of a biodecaffeination process for tea synchronised with tea fermentation process using enzymes isolated from Pseudomonas alcaligenes. Cell-free extract was used for biodecaffeination of tea during fermentation of tea and 80% of the caffeine in the tea dhool was degraded within 90 min of incubation. Several factors that tend to effect the biodecaffeination during this stage, like moisture, aeration, intermittent enzyme addition and mixing, were optimized, and inhibitory interactions of proteins with polyphenols, caffeine-polyphenol interactions, which directly influence the biodecaffeination process were prevented by the use of glycine (5% w/w) in the dhool. Tea decaffeinated through the enzymatic route retained the original flavor and aroma, and there was an increase in the total polyphenol content of the tea.


Assuntos
Cafeína/química , Fermentação , Pseudomonas alcaligenes/enzimologia , Chá/química , Reatores Biológicos , Cafeína/metabolismo , Sistema Livre de Células/enzimologia , Citocromo P-450 CYP1A2/química , Citocromo P-450 CYP1A2/metabolismo , Glicina/química , Microbiologia Industrial , Polifenóis/química
18.
Anal Chim Acta ; 582(2): 329-34, 2007 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-17386510

RESUMO

We have utilized a microbe, which can degrade caffeine to develop an Amperometric biosensor for determination of caffeine in solutions. Whole cells of Pseudomonas alcaligenes MTCC 5264 having the capability to degrade caffeine were immobilized on a cellophane membrane with a molecular weight cut off (MWCO) of 3000-6000 by covalent crosslinking method using glutaraledhyde as the bifunctional crosslinking agent and gelatin as the protein based stabilizing agent (PBSA). The biosensor system was able to detect caffeine in solution over a concentration range of 0.1 to 1 mg mL(-1). With read-times as short as 3 min, this caffeine biosensor acts as a rapid analysis system for caffeine in solutions. Interestingly, successful isolation and immobilization of caffeine degrading bacteria for the analysis of caffeine described here was enabled by a novel selection strategy that incorporated isolation of caffeine degrading bacteria capable of utilizing caffeine as the sole source of carbon and nitrogen from soils and induction of caffeine degrading capacity in bacteria for the development of the biosensor. This biosensor is highly specific for caffeine and response to interfering compounds such as theophylline, theobromine, paraxanthine, other methyl xanthines and sugars was found to be negligible. Although a few biosensing methods for caffeine are reported, they have limitations in application for commercial samples. The development and application of new caffeine detection methods remains an active area of investigation, particularly in food and clinical chemistry. The optimum pH and temperature of measurement were 6.8 and 30+/-2 degrees C, respectively. Interference in analysis of caffeine due to different substrates was observed but was not considerable. Caffeine content of commercial samples of instant tea and coffee was analyzed by the biosensor and the results compared well with HPLC analysis.


Assuntos
Técnicas Biossensoriais , Cafeína/análise , Pseudomonas alcaligenes/química , Calibragem , Cromatografia Líquida de Alta Pressão , Enzimas Imobilizadas/química , Concentração de Íons de Hidrogênio , Sensibilidade e Especificidade , Temperatura , Xantina Oxidase/química
19.
Cytogenet Cell Genet ; 57(1): 16-7, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1855387

RESUMO

Fluorescence in situ hybridization (FISH) is being used increasingly in clinical practice; however, current FISH techniques require fresh material, and there is considerable variation in hybridization efficiency between laboratories. We have modified a FISH technique described by Pinkel et al. (1986) that works not only on freshly G-banded material but also on cytogenetic preparations ranging in age from 2 wk to 12 yr. We have tested this technique on several centromeric alphoid satellite probes (D1Z5, D7Z1, D17Z1, DXZ1, and DYZ3) and one noncentromeric minisatellite probe (D1Z2). Our average hybridization efficiency on freshly banded preparations for these probes is consistently greater than 90%. The combination of higher efficiency and the ability to perform hybridization on previously G-banded material makes this a valuable technique for retrospective analyses.


Assuntos
Hibridização de Ácido Nucleico , Criança , Bandeamento Cromossômico , Sondas de DNA , DNA Satélite/genética , Imunofluorescência , Humanos , Masculino , Estudos Retrospectivos
20.
Ann Hum Biol ; 5(2): 159-63, 1978 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-306798

RESUMO

Among 126 Valmiki, 128 Bagatha, 129 Konda Dora and 73 Samanta tribals of Andhra Pradesh, the incidence of red-green colour-blindness in the males ranges from zero to 2.27 per cent. Samanta males exhibit no colour-blindness. In the females, only Konda Doras exhibit a frequency of 2.44 per cent of the trait. Comparison of the present data with the other available tribal and non-tribal data of Andhra Pradesh shows that our results fall well in the range for other data. Post's (1962) hypothesis of relaxation of selection against colour-blindness is also supported by our Andhra Pradesh data.


Assuntos
Defeitos da Visão Cromática/epidemiologia , Adolescente , Adulto , Idoso , Feminino , Humanos , Índia , Masculino , Pessoa de Meia-Idade , Seleção Genética , Fatores Sexuais
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA