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1.
Gynecol Oncol ; 156(3): 611-615, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31983516

RESUMO

OBJECTIVE: Risk factors for ovarian borderline tumors and low-grade serous carcinoma (LGSC) are poorly understood. The aim of this study was to examine the association between infertility, pelvic inflammatory disease (PID), endometriosis, ectopic pregnancy, hysterectomy, tubal ligation and parity and the risk of serous borderline tumor (SBT), mucinous borderline tumor (MBT) and LGSC. METHODS: This was a population-based cohort study using linked administrative and hospital data. Participants were 441,382 women born between 1945 and 1975 who had been admitted to hospital in Western Australia between 1 January 1980 and 30 June 2014. We used Cox regression to estimate hazard ratios (HRs). RESULTS: We observed an increased rate of SBT associated with infertility, PID and ectopic pregnancy (HRs and 95% CIs were, respectively, 1.98 (1.20-3.26); 1.95 (1.22-3.10) and 2.44 (1.20-4.96)). We did not detect an association between any of the factors under study and the rate of MBT. A diagnosis of PID was associated with an increased rate of LGSC (HR 2.90, 95% CI 1.21-6.94). CONCLUSIONS: The association with PID supports the hypothesis that inflammatory processes within the upper gynaecological tract and/or peritoneum may predispose to the development of SBT and LGSC.


Assuntos
Cistadenocarcinoma Seroso/epidemiologia , Infertilidade/epidemiologia , Neoplasias Císticas, Mucinosas e Serosas/epidemiologia , Neoplasias Ovarianas/epidemiologia , Doença Inflamatória Pélvica/epidemiologia , Gravidez Ectópica/epidemiologia , Adulto , Estudos de Coortes , Cistadenocarcinoma Seroso/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Gradação de Tumores , Neoplasias Císticas, Mucinosas e Serosas/patologia , Neoplasias Ovarianas/patologia , Gravidez , Austrália Ocidental/epidemiologia
2.
Hamostaseologie ; 33(2): 105-12, 2013 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-23364684

RESUMO

The Oklahoma Thrombotic Thrombocytopenic Purpura-Haemolytic Uraemic Syndrome (TTP-HUS) Registry has a 24 year record of success for collaborative clinical research, education, and patient care. This article tells the story of how the Registry began and it describes the Registry's structure and function. The Registry provides a model for using a cohort of consecutive patients to investigate a rare disorder. Collaboration between Oklahoma, United States and Bern, Switzerland has been the basis for successful interpretation of Registry data. Registry data have provided new insights into the evaluation and management of TTP. Because recovery from acute episodes of TTP has been assumed to be complete, the increased prevalence of hypertension, diabetes, depression, and death documented by long-term follow-up was unexpected. Registry data have provided opportunities for projects for students and trainees, education of physicians and nurses, and also for patients themselves. During our follow-up, patients have also educated Registry investigators about problems that persist after recovery from an acute episode of TTP. Most important, Registry data have resulted in important improvements for patient care.


Assuntos
Bases de Dados Factuais , Síndrome Hemolítico-Urêmica/epidemiologia , Púrpura Trombocitopênica Trombótica/epidemiologia , Sistema de Registros/estatística & dados numéricos , Feminino , Síndrome Hemolítico-Urêmica/diagnóstico , Síndrome Hemolítico-Urêmica/terapia , Humanos , Internacionalidade , Masculino , Oklahoma/epidemiologia , Prevalência , Púrpura Trombocitopênica Trombótica/diagnóstico , Púrpura Trombocitopênica Trombótica/terapia , Fatores de Risco , Taxa de Sobrevida
3.
Aust N Z J Public Health ; 28(1): 32-6, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15108744

RESUMO

OBJECTIVE: To compare the risk of death in a cohort of Western Australian released prisoners with the risk experienced by the general population of Western Australia. METHODS: A cohort study of prisoners in Western Australia whose last date of release ranged from 1 January 1994 to 1 January 1999. Overall mortality and cause of death were determined by data linkage to the Registrar General's record of deaths. RESULTS: Aboriginal prisoners had a significantly lower survival rate after release than non-Aboriginal prisoners (p < 0.0001). When compared with their peers in the Western Australian community, both Aboriginal and non-Aboriginal prisoners were found to have an increased relative risk of death. Female non-Aboriginal released prisoners aged between 20 and 40 years were 17.8 (95% CI 8.1-27.5) times more likely to die than other female non-Aboriginals in Western Australia in the same age range. Male non-Aboriginal prisoners aged 20-40 years were 6.3 (95% CI 5.2-7.4) times more likely to die than their counterparts in the WA community. Female Aboriginal released prisoners were 3.4 (95% CI 1.2-5.6) times more likely to die than their peers, while male Aboriginal released prisoners were 2.9 (95% CI 2.2-3.5) times more likely to die. In their first six months after release, female non-Aboriginal prisoners aged 20 to 40 years were 69.1 (95% CI 17.9-120.3) times more likely to die than their counterparts in the WA community. The main causes of excess death were related to drug and alcohol abuse. CONCLUSION: All prisoners were at greater than expected relative risk of death after release from prison, with female non-Aboriginal prisoners at particularly high relative risk.


Assuntos
Mortalidade , Havaiano Nativo ou Outro Ilhéu do Pacífico/estatística & dados numéricos , Prisioneiros/estatística & dados numéricos , Adulto , Causas de Morte , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Prisões , Medição de Risco , Distribuição por Sexo , Análise de Sobrevida , Austrália Ocidental/epidemiologia
4.
J Parasitol ; 89(4): 716-20, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-14533680

RESUMO

Sarcocystis neurona, Neospora caninum, N. hughesi, and Toxoplasma gondii are 4 related coccidians considered to be associated with encephalomyelitis in horses. The source of infection for N. hughesi is unknown, whereas opossums, dogs, and cats are the definitive hosts for S. neurona, N. caninum, and T. gondii, respectively. Seroprevalence of these coccidians in 276 wild horses from central Wyoming outside the known range of the opossum (Didelphis virginiana) was determined. Antibodies to T. gondii were found only in 1 of 276 horses tested with the modified agglutination test using 1:25, 1:50, and 1:500 dilutions. Antibodies to N. caninum were found in 86 (31.1%) of the 276 horses tested with the Neospora agglutination test--the titers were 1:25 in 38 horses, 1:50 in 15, 1:100 in 9, 1:200 in 8, 1:400 in 4, 1:800 in 2, 1:1,600 in 2, 1:3,200 in 2, and 1:12,800 in 1. Antibodies to S. neurona were assessed with the serum immunoblot; of 276 horses tested, 18 had antibodies considered specific for S. neurona. Antibodies to S. neurona also were assessed with the S. neurona direct agglutination test (SAT). Thirty-nine of 265 horses tested had SAT antibodies--in titers of 1:50 in 26 horses and 1:100 in 13. The presence of S. neurona antibodies in horses in central Wyoming suggests that either there is cross-reactivity between S. neurona and some other infection or a definitive host other than opossum is the source of infection. In a retrospective study, S. neurona antibodies were not found by immunoblot in the sera of 243 horses from western Canada outside the range of D. virginiana.


Assuntos
Anticorpos Antiprotozoários/sangue , Coccidiose/veterinária , Doenças dos Cavalos/epidemiologia , Neospora/imunologia , Sarcocystis/imunologia , Toxoplasma/imunologia , Testes de Aglutinação/veterinária , Animais , Coccidiose/epidemiologia , Feminino , Doenças dos Cavalos/imunologia , Cavalos , Masculino , Manitoba/epidemiologia , Sarcocistose/epidemiologia , Sarcocistose/veterinária , Saskatchewan/epidemiologia , Estudos Soroepidemiológicos , Toxoplasmose Animal/epidemiologia , Wyoming/epidemiologia
6.
Neuropsychologia ; 39(4): 415-9, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11164880

RESUMO

OBJECTIVE: To investigate the stability of visual phosphene thresholds and to assess whether they correlate with motor thresholds. BACKGROUND: Currently, motor threshold is used as an index of cortical sensitivity so that in transcranial magnetic stimulation (TMS) experiments, intensity can be set at a given percentage of this value. It is not known whether this is a reasonable index of cortical sensitivity in non-motor and hence whether it should be used in experiments where other cortical areas are targeted. Previous studies have indicated that phosphene threshold might be a suitable alternative in TMS studies of the visual system. METHOD: Using single pulse TMS visual phosphene and motor thresholds were measured in 15 subjects. Both thresholds were retested in seven of these subjects a week later. RESULT: Visual phosphene thresholds, though stable within subjects across the two sessions, showed greater variability than motor thresholds. There was no correlation between the two measures. CONCLUSION: TMS motor thresholds cannot be assumed to be a guide to visual cortex excitability and by extension are probably an inappropriate guide to the cortical excitability of other non-motor areas of the brain. Phosphene thresholds are proposed as a potential standard for inter-individual comparison in visual TMS experiments.


Assuntos
Córtex Cerebral/fisiologia , Destreza Motora/fisiologia , Fosfenos/fisiologia , Adulto , Estimulação Elétrica , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Limiar Sensorial , Estimulação Magnética Transcraniana
7.
Br J Cancer ; 82(10): 1671-6, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10817502

RESUMO

PTEN, a putative tumour suppressor gene associated with prostate and other cancers, is known to be located within the chromosomal region 10q23.3. Transcription of the PTEN gives rise to multiple mRNA species. Analyses by Northern blots, using cell lines which express PTEN together with cell lines which have lost the PTEN or carry a truncated version of the gene, has allowed us to demonstrate that the pseudogene is not transcribed. In addition, 3' RACE studies confirmed that the multiple mRNA species arising from the gene probably result from the use of alternative polyadenylation sites. No evidence for tissue- or cell-specific patterns of transcription was found. Analysis by 5' RACE placed the putative site for the start of transcription around 830 bp upstream of the start codon. A map of the location of the PTEN gene with a series of overlapping YAC, BAC and PACs has been constructed and the relative position of eight microsatellite markers sited. Two known and one novel marker have been positioned within the gene, the others are in flanking regions. The more accurate location of these markers should help in future studies of the extent of gene loss. Several polymorphisms were also identified, all were within introns. Four of the common polymorphisms appear to be linked. In blood, DNA from 200 individuals, including normal, BPH and prostate cancer patients, confirmed this link. Only two samples of 200 did not carry the linked haplotype, both were patients with advanced prostate cancer. It is possible that such rearrangements within PTEN could be evidence of predisposition to prostate cancer in this small number of cases.


Assuntos
Cromossomos Humanos Par 10/genética , Genes Supressores de Tumor/genética , Perda de Heterozigosidade , Monoéster Fosfórico Hidrolases/genética , Polimorfismo Genético , Proteínas Supressoras de Tumor , Processamento Alternativo , Northern Blotting , Mapeamento Cromossômico/métodos , Cromossomos Artificiais de Levedura/genética , Cromossomos Bacterianos/genética , Marcadores Genéticos , Humanos , Repetições de Microssatélites/genética , PTEN Fosfo-Hidrolase , RNA Mensageiro/genética , Células Tumorais Cultivadas
8.
Cancer Immunol Immunother ; 47(6): 299-306, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10203059

RESUMO

Carcinoembryonic antigen (CEA) is highly expressed by most tumours of gastrointestinal origin, but its use as a target for tumour therapy is complicated by the high levels of soluble CEA that are found circulating in the blood of cancer patients. A monoclonal antibody PR1A3 has been prepared, which binds preferentially to cell-surface rather than soluble CEA, this cell selectivity should make PR1A3 an ideal candidate for antibody-targeted tumour therapy. PR1A3 has been humanised and shown to retain its cell-surface specificity and affinity. Stable expression of the humanised antibody from chinese hamster ovary (CHO) cells has been achieved after transfection and amplification. Since PR1A3 binds preferentially to cell-associated CEA, a cell-free enzyme-linked immunosorbent assay (ELISA) has been developed to allow characterisation and routine assay of the antibody. This assay was developed using a recombinant chimeric protein constructed by cloning the domain of CEA that is bound by PR1A3 (the B3 domain) into a hybrid gene containing the Fc portion of IgG and three domains of biliary glycoprotein. Stable expression of this hybrid protein has been achieved from CHO cells. In ELISA both humanised and murine PR1A3 bound strongly to this antigen but only at a minimal level to soluble CEA. Two binding sites for the antibody were found on the gastric carcinoma cell line MKN45, one of higher affinity (1 nM) and the other at lower affinity (60 nM). Similar affinities were found for both murine and humanised antibodies. The data presented make it unlikely that the differential binding to cell-surface as distinct from soluble CEA can be accounted for by low affinity of PR1A3 for CEA, and provides further support for the hypothesis that some conformational change takes place on CEA release from cells and that it is this change that blocks PR1A3 binding to its epitope.


Assuntos
Anticorpos Monoclonais/química , Anticorpos Monoclonais/metabolismo , Especificidade de Anticorpos , Antígeno Carcinoembrionário/genética , Antígeno Carcinoembrionário/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/genética , Anticorpos Monoclonais Murinos , Afinidade de Anticorpos , Células CHO , Células COS/metabolismo , Antígeno Carcinoembrionário/metabolismo , Clonagem Molecular , Cricetinae , Epitopos/imunologia , Epitopos/metabolismo , Humanos , Camundongos , Dados de Sequência Molecular , Ligação Proteica/imunologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência de Aminoácidos , Neoplasias Gástricas/imunologia , Neoplasias Gástricas/metabolismo
9.
Br J Cancer ; 78(10): 1296-300, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9823969

RESUMO

The chromosomal region 10q23-24 is frequently deleted in a number of tumour types, including prostate adenocarcinoma and glioma. A candidate tumour-suppressor gene at 10q23.3, designated PTENor MMAC1, with putative actin-binding and tyrosine phosphatase domains has recently been described. Mutations in PTEN have been identified in cell lines derived from gliomas, melanomas and prostate tumours and from a number of tumour specimens derived from glial, breast, endometrial and kidney tissue. Germline mutations in PTEN appear to be responsible for Cowden disease. We identified five PTEN mutations in 37 primary prostatic tumours analysed and found that 70% of tumours showed loss or alteration of at least one PTEN allele, supporting the evidence for PTEN involvement in prostate tumour progression. We raised antisera to a peptide from PTEN and showed that reactivity occurs in numerous small cytoplasmic organelles and that the protein is commonly expressed in a variety of cell types. Northern blot analysis revealed multiple RNA species; some arise as a result of alternative polyadenylation sites, but others may be due to alternative splicing.


Assuntos
DNA de Neoplasias/genética , Regulação Neoplásica da Expressão Gênica , Genes Supressores de Tumor , Monoéster Fosfórico Hidrolases/genética , Neoplasias da Próstata/genética , Proteínas Supressoras de Tumor , Sequência de Aminoácidos , Northern Blotting , Análise Mutacional de DNA , Humanos , Masculino , Dados de Sequência Molecular , PTEN Fosfo-Hidrolase , RNA Neoplásico/análise
10.
J Mol Biol ; 284(3): 713-28, 1998 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-9826510

RESUMO

The anti-breast tumour antibody SM3 has a high selectivity in reacting specifically with carcinoma-associated mucin. SM3 recognises the core repeating motif (Pro-Asp-Thr-Arg-Pro) of aberrantly glycosylated epithelial mucin MUC1, and has potential as a therapeutic and diagnostic tool. Here we report the crystal structure of the Fab fragment of SM3 in complex with a 13-residue MUC1 peptide antigen (Thr1P-Ser2P-Ala3P-Pro4P-Asp5P-Thr6P -Arg7P-Pro8P-Ala9P-Pro10P-Gly11P- Ser12P-Thr13P). The SM3-MUC1 peptide structure was solved by molecular replacement, and the current model is refined at 1.95 A resolution with an R-factor of 21.3% and R-free 28.3%. The MUC1 peptide is bound both by non-polar interactions and hydrogen bonds in an elongated groove in the antibody-combining site through interactions with Complimentarity Determining Regions (CDRs), three of the light chain (L1, L2, L3) and two of the heavy chain (H1 and H3). The conformation of the peptide is mainly extended with no discernable standard secondary structure. There is a single non-proline cis-peptide bond in H3 (Val95H-Gly96H-Gln97H-Phe98H-Ala101H-Ty r102H) between Gly96H and Gln97H, which appears to play a role in SM3-peptide antigen interactions, and represents the first such example within an antibody hypervariable loop. The SM3-MUC1 peptide structure has implications for rational therapeutic and diagnostic antibody engineering.


Assuntos
Anticorpos Antineoplásicos/química , Neoplasias da Mama/imunologia , Epitopos/química , Fragmentos Fab das Imunoglobulinas/química , Mucinas/química , Peptídeos/química , Sequência de Aminoácidos , Reações Antígeno-Anticorpo , Modelos Moleculares
11.
Semin Speech Lang ; 19(2): 167-86; quiz 186-7, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9621402

RESUMO

Semantic content categories were described for the single word, multiple word, and verb relation utterances of 22 African-American 2-year-olds during a 90-min laboratory session. Half of the toddlers had been exposed prenatally to cocaine and half were unexposed, as documented by biological assay in the newborn period. The exposed and unexposed groups were carefully matched on demographic, medical, and proximal caregiving variables. Children's spontaneous utterances were transcribed from audio- and videotapes during the laboratory session and scored for semantic features by a team of reliable coders who were masked to child exposure status. General productive language features (utterance length, verbosity, and intelligibility) were also assessed. To evaluate general language and cognitive skills, the toddlers were evaluated with the Sequenced Inventory of Communicative Development-Revised (SICD-R) and the Bayley Scales of Infant Development (BSID). Although exposed and nonexposed toddlers exhibited similar sequences of semantic development, the exposed toddlers were more restricted and delayed in their semantic representations. No significant group differences were observed, however, for structural features of language (e.g., utterance length, distribution of utterance types) or for children's general language and cognitive functioning as assessed by standardized assessments (i.e., SICD-R, BSID). Thus, a history of prenatal cocaine exposure and associated risk factors (e.g., prenatal exposure to alcohol, diminished birth weight) are related to delays in early semantic development. Proposed diagnostic and treatment strategies are discussed.


Assuntos
Negro ou Afro-Americano , Transtornos do Desenvolvimento da Linguagem/etiologia , Comportamento Materno/psicologia , Efeitos Tardios da Exposição Pré-Natal , Semântica , Criança , Pré-Escolar , Feminino , Humanos , Transtornos do Desenvolvimento da Linguagem/diagnóstico , Estudos Longitudinais , Gravidez
13.
Int J Antimicrob Agents ; 6(4): 183-7, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18611707

RESUMO

RMP-7, a nine-amino acid bradykinin analogue, has been shown in animals to temporarily increase the permeability of the blood brain barrier to small molecules including amphotericin B, when administered intravenously. We sought to evaluate the safety of escalating doses of RMP-7 administered to human volunteers with the acquired immune deficiency syndrome (AIDS). Six HIV antibody-positive adults with CD4+ cell counts <50/mm3 received three increasing doses of RMP-7 on successive days: 30 ng/kg, 100 ng/kg and 300 ng/kg infused over 2, 2 and 10 min, respectively. Adverse experiences were dose-related, mild-moderate in intensity, primarily related to vasodilation and resolved rapidly without sequelae. Mean maximum increases in pulse rate at 30 ng/kg, 100 ng/kg and 300 ng/kg were 4.0, 7.8 and 28.2 beats per min, respectively. The maximum changes in average mean arterial pressure were +7.7, +5.6 and -0.2 mmHg from baseline, respectively. Minor increases in liver enzymes were noted in three patients, all with pre-existing enzyme elevations. Despite the high frequency of both occult and overt cardiovascular abnormalities in advanced HIV infection, RMP-7 is shown to be safe in this group of AIDS patients at all dosage levels tested, with adverse effects similar to previous experience in healthy humans.

14.
Proc Natl Acad Sci U S A ; 91(10): 4313-7, 1994 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-7514303

RESUMO

The monoclonal antibody PR1A3 has been used successfully for in vivo imaging of colorectal cancers, and several properties associated with this antibody, including minimal reactions of the antibody with circulating antigen in patients' sera, differentiate it from anti-carcinoembryonic antigen (CEA) antibodies used in similar studies. However, the antigen bound by PR1A3 was identified as CEA by analysis of somatic cell hybrids and by antigen expression from yeast artificial chromosomes, cosmids, and cDNA clones. The molecular weight, presence of a glycosyl-phosphatidylinositol anchor, elevation of surface expression by gamma-interferon, and N-terminal amino acid sequence all confirmed the antigen identification as CEA. A series of biliary glycoprotein-CEA hybrid proteins was produced which demonstrated that the epitope bound by the antibody was at the site of membrane attachment and involved parts of the glycosyl-phosphatidylinositol anchor and the B3 domain of CEA to form a conformational epitope. Access to this epitope, although possible when the antigen was on the cell surface, appeared to be blocked when CEA was released from the cell. The nature and location of the epitope on CEA are proposed to be responsible for the unique properties of the antibody.


Assuntos
Anticorpos Monoclonais , Antígeno Carcinoembrionário/análise , Antígeno Carcinoembrionário/genética , Cromossomos Humanos Par 19 , Epitopos/análise , Animais , Anticorpos Monoclonais Murinos , Sequência de Bases , Antígeno Carcinoembrionário/biossíntese , Linhagem Celular , Chlorocebus aethiops , Mapeamento Cromossômico , Cromossomos Artificiais de Levedura , Neoplasias do Colo , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Expressão Gênica/efeitos dos fármacos , Glicosilfosfatidilinositóis/metabolismo , Humanos , Células Híbridas , Immunoblotting , Interferon gama/farmacologia , Camundongos , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos , Reação em Cadeia da Polimerase , Conformação Proteica , Proteínas Recombinantes de Fusão/análise , Proteínas Recombinantes de Fusão/biossíntese , Neoplasias Retais , Neoplasias Gástricas , Transfecção , Células Tumorais Cultivadas
15.
Nature ; 352(6330): 85-8, 1991 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-2062383

RESUMO

Baculoviruses provide alternatives to chemicals for controlling insect pests and can be applied by spraying. Baculoviruses have a limited host range, but work relatively slowly. They are dissolved in the midgut of insect larvae to release infectious virions which enter gut epithelial cells and begin to replicate. Replication in other organs causes extensive tissue damage and eventually death. This process can take 4-5 days, but in the field may last for more than a week, allowing the larvae to feed for longer and thereby damaging the host plant. Baculovirus expression vectors expressing foreign genes, such as those for insect-specific toxins, hormones or enzymes, might alleviate this problem. We have now constructed a recombinant baculovirus derived from Autographa californica nuclear polyhedrosis virus containing an insect-specific neurotoxin from the venom of the North African (Algerian) scorpion, Androctonus australis Hector. The neurotoxin acts by causing specific modifications to the Na+ conductance of neurons, producing a presynaptic excitatory effect leading to paralysis and death; it has no effect in mice. Expression of the neurotoxin by the virus causes a reduction in the time required to kill the host insect.


Assuntos
Baculoviridae/genética , Inseticidas , Neurotoxinas/genética , Controle Biológico de Vetores , Recombinação Genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Expressão Gênica , Dados de Sequência Molecular , Neurotoxinas/toxicidade
16.
Stroke ; 20(12): 1716-23, 1989 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2512692

RESUMO

Regional cerebral blood flow was simultaneously determined using the stable xenon computed tomographic and the radioactive microsphere techniques over a wide range of blood flow rates (less than 10-greater than 300 ml/100 g/min) in 12 baboons under conditions of normocapnia, hypocapnia, and hypercapnia. A total of 31 pairs of determinations were made. After anesthetic and surgical preparation of the baboons, cerebral blood flow was repeatedly determined using the stable xenon technique during saturation with 50% xenon in oxygen. Concurrently, cerebral blood flow was determined before and during xenon administration using 15-microns microspheres. In Group 1 (n = 7), xenon and microsphere determinations were made repeatedly during normocapnia. In Group 2 (n = 5), cerebral blood flow was determined using both techniques in each baboon during hypocapnia (PaCO2 = 20 mm Hg), normocapnia (PaCO2 = 40 mm Hg), and hypercapnia (PaCO2 = 60 mm Hg). Xenon and microsphere values in Group 1 were significantly correlated (r = 0.69, p less than 0.01). In Group 2, values from both techniques also correlated closely across all levels of PaCO2 (r = 0.92, p less than 0.001). No significant differences existed between the slopes or y intercepts of the regression lines for either group and the line of identity. Our data indicate that the stable xenon technique yields cerebral blood flow values that correlate well with values determined using radioactive microspheres across a wide range of cerebral blood flow rates.


Assuntos
Circulação Cerebrovascular , Microesferas , Xenônio , Animais , Artérias , Dióxido de Carbono/sangue , Feminino , Hipercapnia/fisiopatologia , Masculino , Papio , Pressão Parcial , Valores de Referência , Tomografia Computadorizada por Raios X
17.
Invest Radiol ; 22(9): 705-12, 1987 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3679761

RESUMO

We performed a series of five baboon experiments to compare cerebral blood flow measured with an improved stable xenon/CT method and the radiolabelled microsphere technique at a PaCO2 of 40 mm Hg. The xenon/CT method was implemented by fitting the arterial xenon uptake with a double exponential function, by measuring the oxygen and carbon dioxide concentrations continuously during each breath and by taking into account the lung-to-brain transit time of xenon. The time of xenon inhalation was extended to 30 minutes to obtain more reliable estimates of CBF in white matter regions. The results indicate an overall correlation coefficient of 0.92 between the two methods and good numeric agreement.


Assuntos
Circulação Cerebrovascular , Tomografia Computadorizada por Raios X , Radioisótopos de Xenônio , Animais , Feminino , Masculino , Microesferas , Papio
18.
J Bacteriol ; 164(2): 904-10, 1985 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-2865250

RESUMO

The phs mutation of Escherichia coli has been suggested to affect the Na+/H+ antiport (D. Zilberstein, E. Padan, and S. Schuldiner, FEBS Lett. 168:327-330, 1980). We have recently shown that the mutation affects the rpoA gene and thus affects transcription. The extent of the pleiotropy of the phs mutation was investigated. In addition to the previously reported growth defect on L-glutamate and melibiose, the mutation also affects at least two other metabolic systems. The transport and metabolism of arabinose is impaired and the transport of sulfate is reduced. The extent to which the effects of the phs mutation on metabolism are due to a defect in the Na+/H+ antiport was investigated, and no causal role for this transport system in the metabolic defects was found.


Assuntos
RNA Polimerases Dirigidas por DNA/genética , Escherichia coli/genética , Genes Bacterianos , Arabinose/metabolismo , Transporte Biológico , Proteínas de Transporte/metabolismo , Cisteína/biossíntese , Escherichia coli/enzimologia , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Glutamatos/metabolismo , Ácido Glutâmico , Melibiose/metabolismo , Mutação , Fenótipo , Potássio/metabolismo , Prolina/metabolismo , Sódio/metabolismo , Sódio/farmacologia , Trocadores de Sódio-Hidrogênio , Sulfatos/metabolismo
19.
J Gen Microbiol ; 131(1): 77-85, 1985 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-3886836

RESUMO

The dual energy requirement (protonmotive force and ATP) of the Escherichia coli Trk potassium transport system has been investigated. Using inhibitors and unc mutants we show that Trk is not an ATPase but may be regulated by ATP. Possible mechanisms of energy coupling to Trk are discussed.


Assuntos
Trifosfato de Adenosina/metabolismo , Metabolismo Energético , Escherichia coli/metabolismo , Potássio/metabolismo , Arseniatos/farmacologia , Transporte Biológico/efeitos dos fármacos , Iodoacetatos/farmacologia , Ácido Iodoacético , Metilgalactosídeos/metabolismo , Tiogalactosídeos/metabolismo
20.
J Comput Assist Tomogr ; 8(4): 619-30, 1984 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-6736359

RESUMO

Several theoretical and practical aspects of regional cerebral blood flow measurements using stable xenon gas and CT are discussed. It is shown that by comparing the enhancement at any time T1 with that at saturation or any other time T2, the need to use arbitrary means to bring the arterial concentration data and the CT enhancement data to the same system of measurement units can be eliminated. If CT is performed continuously during the washin phase, say at intervals of 1 min, least squares analysis of the enhancement data can be used to obtain the best possible estimates for the flow rate constant kappa and the saturation enhancement. However, if only a limited number of scans can be performed, as may be the case in human studies, it is also possible to get a good estimate of kappa from a knowledge of the ratio of the enhancement at any time T1 with that at any other time T2. Combinations of T1 = 2.0 min and T2 = 4.0 min, T1 = 1.0 min and T2 = 6.0 min, or T1 = 2.0 min and T2 = 5.0 min were found to be the most convenient. It is also shown that the end-tidal xenon concentration in the exhaled air can be accurately assessed indirectly by measuring the oxygen, CO2, and water vapor concentrations, thereby eliminating the need for more expensive methods involving the use of a mass spectrometer or a thermal conductivity gas analyzer.


Assuntos
Circulação Cerebrovascular , Intensificação de Imagem Radiográfica , Tomografia Computadorizada por Raios X , Xenônio , Animais , Velocidade do Fluxo Sanguíneo , Encéfalo/diagnóstico por imagem , Infarto Cerebral/diagnóstico por imagem , Humanos , Oxigênio/fisiologia , Papio , Fenômenos Físicos , Física
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