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1.
Radiologe ; 60(8): 729-736, 2020 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-32322924

RESUMO

PURPOSE: To evaluate teleradiology examinations regarding the most frequently requested exams and examined body regions. Additionally, the frequency of pathological changes depending on the examined region and clinical situation as well as the time profile for requesting teleradiology (daytime, day of the week) were analyzed. MATERIALS AND METHODS: A retrospective analysis of all consecutive teleradiology exams in 2018 that were reported in the radiology department of a major regional hospital and scanned in three referring primary health care institutions regarding clinical history, working diagnosis and requested body region was performed. Additionally, the date and time of the examination were analyzed. RESULTS: A total of 1207 CT (computer tomography) scans that were reported as part of the teleradiology agreement were included. The most frequently requested examination was a cranial CT (77.9%) with 14.6% pathological findings, followed by abdominal CT (14%) with 63.9% pathological changes, spine/extremities (8.8%) with 50% pathological changes and CT of the chest (7.9%) with 53.7% abnormal scans. Most teleradiology requests were referred on weekends between 8 am and 4 pm, followed by 4 pm to 6 pm on weekdays. The smallest number of scans was requested between 2 am and 4 am. CONCLUSION: Most teleradiology CT requests focus on brain examinations, followed by abdominal CT, CT of the spine and extremities and CT chest. Most cranial CTs do not show an acute pathology, while abdominal CTs had the highest rate of pathological findings.


Assuntos
Telerradiologia/estatística & dados numéricos , Humanos , Serviço Hospitalar de Radiologia , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/estatística & dados numéricos
2.
Health Phys ; 2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-39051997

RESUMO

ABSTRACT: Naturally occurring uranium complicates monitoring for occupational exposures. There are several retroactive methods that can be used to monitor for occupational exposures, with benefits and drawbacks to each. Analysis of uranium in urine by mass spectrometry and alpha spectrometry is compared, and methods of determining an occupational exposure are presented. The minimum detectable concentrations from each analysis and a method for intake determination based on the analytical results are compared for various solubility types and mixtures. Mass spectrometry with radiochemical separation was found to be the most sensitive analysis for detecting occupational exposures to anthropogenic mixtures based on minimum detectable doses calculated from the proposed method for intake determination.

3.
Cancer Res ; 37(11): 3932-8, 1977 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-409489

RESUMO

Eight ergot alkaloids and ergoline derivatives, effective prolactin inhibitors, were tested for activity against DMBA-induced rat mammary carcinomas. Compounds were administered daily, 5 times/week for 4 weeks, and rats were observed for an additional 4 weeks. Groups treated with androgen and estrogen were used as positive controls. Those ergot compounds and ergolines that proved to be highly effective in reducing tumor size or in inducing regression of tumors to nonpalpability were Deprenon (D-6-methyl-8-ergolin-I-ylacetic acid amide) and ergocryptine; effective to an intermediate degree were Dironyl [N-(D-6-methyl-8-isoergolin-I-yl)-N',N'-diethylurea], ergocornine, and Lysenyl [N-(D-6-methyl-8-isoergolenyl)-N',N'-diethyl-urea]; and effective to a minimal degree were Lergotrile (2-chloro-6-methylergoline-8beta-acetonitrile), CB-154, and 6605-VUFB (D-6-methyl-8-cyanomethylergolin-I). Remission of many individual carcinomas was brief, and duration of complete regression (all tumors in the rat were nonpalpable) was less than 10 weeks.


Assuntos
Androstanóis/análogos & derivados , Estradiol/uso terapêutico , Neoplasias Mamárias Experimentais/tratamento farmacológico , Prolactina/antagonistas & inibidores , 9,10-Dimetil-1,2-benzantraceno , Acetonitrilas/uso terapêutico , Androstanóis/uso terapêutico , Animais , Neoplasias da Mama/tratamento farmacológico , Bromocriptina/uso terapêutico , Avaliação Pré-Clínica de Medicamentos , Ergolinas/uso terapêutico , Alcaloides de Claviceps/uso terapêutico , Feminino , Humanos , Lisurida/análogos & derivados , Neoplasias Mamárias Experimentais/sangue , Prolactina/sangue , Ratos , Ureia/análogos & derivados
4.
Panminerva Med ; 47(4): 229-44, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16489322

RESUMO

The insulin resistance (metabolic) syndrome (IRS), also known as syndrome X, is characterized by a clustering of factors associated with cardiovascular risk (obesity, impaired glucose metabolism, hypertension, and dyslipidemia). As reported from the third National Health and Nutrition Examination survey, the IRS is present in approximately 24% of adults in the United States and is strongly associated with coronary heart disease, stroke, type 2 diabetes, and all-cause mortality. Of equal importance, it is now clear that the origins of the IRS extend back into childhood (the IRS is found in approximately 4-10% of children and adolescents) and that the high prevalence of adult IRS is strongly linked to the development of cardiovascular risk during childhood and tracking of the components of the IRS into adulthood. The goal of this review is to present a summary of the currently available information on the IRS in the pre-adult age group with reference to adult studies only when necessary for clarification. The review will specifically summarize insulin resistance in childhood; the important influence of obesity and, in particular, visceral fat, on insulin resistance and the IRS; differences between ethnic groups; relations to adipocytokines, inflammatory factors and oxidative stress; relations of hypertension and lipids to insulin resistance; familial factors; endocrine complications; and potential therapeutic effects from diet and physical activity. Despite the lesser amount of basic and clinical information on childhood IRS in comparison to information available from adult studies, there can now be little doubt that the adverse associations among risk factors comprising the IRS begin in childhood. The challenge is to identify etiologic relations and develop intervention strategies designed to reduce the increasing prevalence of type 2 diabetes and cardiovascular disease.


Assuntos
Síndrome Metabólica/etiologia , Adolescente , Proteína C-Reativa/análise , Criança , Humanos , Hipertensão/complicações , Resistência à Insulina , Gordura Intra-Abdominal/metabolismo , Leptina/sangue , Lipoproteínas VLDL/metabolismo , Síndrome Metabólica/epidemiologia , Síndrome Metabólica/etnologia , Síndrome Metabólica/terapia , Obesidade/complicações , Estresse Oxidativo , Fatores de Risco
5.
Sci Total Environ ; 351-352: 344-68, 2005 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-16154619

RESUMO

Organochlorine pesticides and PCBs were analysed in blubber from beluga (Delphinapterus leucas), or white whales, collected at 15 sites in the Canadian Arctic between 1993 and 2001. The objective of the study was to define and interpret the spatial trends of major organic contaminants in northern beluga in terms of sources and transport pathways, and the biological factors influencing accumulation. When compared on a lipid weight basis, the concentrations of beta-HCH, cis-CHL and SigmaCHL, cis-nonachlor, heptachlor epoxide and p,p'-DDT were significantly higher in males than females at all five sites in the eastern Arctic where the two sexes were harvested. The differences were attributed to losses from the females during fetal development and lactation as reported in previous studies. Major compounds increased with age in males at most sites, however the lack of a significant increase with age at some sites was in part due to high organochlorine concentrations in young year classes (2-5 years), particularly at eastern sites such as Iqaluit and Pangnirtung. Lower concentrations of SigmaHCH and SigmaDDT compounds in young males in 2001 relative to 1995 at Hendrickson Island could be due to declining levels in the environment, changes in the diet, or differences in organochlorine loads transferred from the female after birth. Age-corrected least square mean concentrations in males showed significantly higher levels of many compounds, such as p,p'-DDE and SigmaCHB, at south Baffin Island sites than those in the west. Two notable exceptions were HCBz and beta-HCH which were higher in the west. Methoxyclor was detected in males at Sanikiluaq (58 ng g-1) and in both sexes at Kimmirut, but at no other sites. Principal component analysis grouped the 16 sites into five major groupings based on the similarity of normalised organochlorine pesticide and PCB levels. Sites from the western Arctic were grouped by higher proportions of HCBz, beta-HCH and gamma-HCH and higher chlorinated PCBs. Endosulfan and alpha-HCH comprised a larger proportion of total organochlorine residues in the northern Hudson Bay sites, while methoxychlor, chlordane compounds and octachlorobiphenyls were enriched at Sanikiluaq in eastern Hudson Bay. The analysis showed that the relative amounts of several key compounds are similar in the beluga stocks over large spatial areas (i.e. eastern versus western sites), however, some stocks have distinct fingerprints which can be used to differentiate them from adjacent stocks. Ratios of major HCH isomers largely corresponded with air and surface water measurements conducted during the 1990s, but low alpha-/beta- and alpha-/gamma-HCH ratios in all three western Arctic collections indicate rapid losses of the alpha-isomer from the food web, proportionately higher beta- and gamma-isomers in the Beaufort Sea, or a combination of the two processes. Chlordane residue patterns generally correspond to those from previous studies, however, interpretation of spatial trends are difficult due to the aging of the probable sources in the south, possible atmospheric input from new sources and complex transport pathways.


Assuntos
Beluga , Hidrocarbonetos Clorados/análise , Poluentes Químicos da Água/análise , Tecido Adiposo/química , Animais , Regiões Árticas , Canadá , Monitoramento Ambiental , Feminino , Masculino , Praguicidas/análise , Análise de Componente Principal
6.
Sci Total Environ ; 342(1-3): 223-43, 2005 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-15866277

RESUMO

Two annually laminated cores collected from Lake DV09 on Devon Island in May 1999 were dated using 210Pb and 137Cs, and analyzed for a variety of halogenated organic contaminants (HOCs), including polychlorinated biphenyls (PCBs), organochlorine pesticides, short-chain polychlorinated n-alkanes (sPCAs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated diphenyl ethers (PBDEs). Dry weight HOC concentrations in Lake DV09 sediments were generally similar to other remote Arctic lakes. Maximum HOC fluxes often agreed well with production maxima, although many compound groups exhibited maxima at or near the sediment surface, much later than peak production. The lower than expected HOC concentrations in older sediment slices may be due to anaerobic degradation and possibly to dilution resulting from a temporary increase in sedimentation rate observed between the mid-1960s and 1970s. Indeed, temporal trends were more readily apparent for those compound classes when anaerobic metabolites were also analyzed, such as for DDT and toxaphene. However, it is postulated here for the first time that the maximum or increasing HOC surface fluxes observed for many of the major compound classes in DV09 sediments may be influenced by climate variation and the resulting increase in algal primary productivity which could drive an increasing rate of HOC scavenging from the water column. Both the fraction (F(TC)) and enantiomer fraction (EF) of trans-chlordane (TC) decreased significantly between 1957 and 1997, suggesting that recent inputs to the lake are from weathered chlordane sources. PCDD/Fs showed a change in sources from pentachlorophenol (PeCP) in the 1950s and 1960s to combustion sources into the 1990s. Improvements in combustion technology may be responsible for the reducing the proportion of TCDF relative to OCDD in the most recent slice.


Assuntos
Benzofuranos/metabolismo , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Éteres Fenílicos/metabolismo , Bifenil Polibromatos/metabolismo , Dibenzodioxinas Policloradas/análogos & derivados , Dibenzodioxinas Policloradas/metabolismo , Regiões Árticas , Bactérias Anaeróbias , Benzofuranos/análise , Biodegradação Ambiental , Canadá , Clima , Dibenzofuranos Policlorados , Monitoramento Ambiental , Eucariotos , Efeito Estufa , Éteres Difenil Halogenados , Éteres Fenílicos/análise , Bifenil Polibromatos/análise , Dibenzodioxinas Policloradas/análise , Abastecimento de Água
7.
Mol Immunol ; 30(13): 1165-75, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8413321

RESUMO

Quantitative data are presented showing that the method most commonly used to immobilize antibodies in microtiter immunoassays functionally inactivates most of the antibodies. These results were collected using five affinity purified polyclonal antibodies (pAbs) and six monoclonal antibodies (mAbs) specific for fluorescein (FLU) as capture antibodies (CAbs). These CAbs were tested for their ability to capture FLU4.2-BSA after immobilization by passive adsorption, the Protein-Avidin-Biotin-Capture (PABC) system or using previously adsorbed anti-globulins. Results indicate that under optimal conditions, < 10% of monoclonal capture antibody equivalents (CAbeqv) and congruent to 22% of polyclonal CAbeqv remain functional after passive adsorption. Immobilization via the PABC system improved the performance of mAbs by more than five-fold but had less than a two-fold effect on pAbs. Many CAbs immobilized using an anti-globulin retained full activity including the ability to bind two molecules of FLU4.2-BSA/molecule of CAb. The latter result is not necessarily a recommendation for the use of anti-globulin immobilization, since the number of functional CAbeqv per well is not significantly greater than that which can be achieved using passive adsorption.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Adsorção , Animais , Anticorpos/imunologia , Anticorpos Monoclonais , Fluoresceína , Fluoresceínas , Haptenos/imunologia , Camundongos , Desnaturação Proteica
8.
J Clin Endocrinol Metab ; 40(5): 850-5, 1975 May.
Artigo em Inglês | MEDLINE | ID: mdl-123927

RESUMO

Dehydroisoandrosterone (DHA) and cortisol were measured by radioimmunoassay and protein binding techniques respectively in plasma from blood taken at 20-min intervals over 24-h periods in 3 normal men, 2 women with Stein-Leventhal syndrome and a man with a benign adrenocortical adenoma. In all subjects but the latter, DHA and cortisol were episodic and synchronous throughout the entire day; in this patient, continuous secretion of cortisol by the tumor apparently abolished stimulation of the contralateral adrenal, and DHA production was negligible. Dehydroisoandrosterone sulfate analysis in plasma displayed a pattern which, probably because of its origin both by secretion and sulfation and its long half-life showed less synchronicity with DHA and cortisol and less fluctuation than did the free hormones.


Assuntos
Ritmo Circadiano , Desidroepiandrosterona/sangue , Hidrocortisona/sangue , Adenoma/sangue , Neoplasias do Córtex Suprarrenal/sangue , Adulto , Idoso , Feminino , Humanos , Masculino , Síndrome do Ovário Policístico/sangue , Radioimunoensaio , Ácidos Sulfúricos/sangue , Fatores de Tempo
9.
Clin Pharmacol Ther ; 26(3): 294-305, 1979 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-466923

RESUMO

Often drug dosage may be chosen rationally by use of plasma concentration (CP) as the "therapeutic" end point. The ability to accurately forecast the CP resulting from a dosage regimen is central to choosing that regimen. Tradionally forecasting has been attempted only by accounting for known influences on pharmacokinetics, such as sex, age, and renal disease. One must also adjust for previously observed CPs. Herein, we discuss and explain an approach to both of these tasks, mainly focusing on the latter. The approach balances observed outcomes against prior expectations taking account of observation CP error. For digoxin, use of 1 measured CP, as opposed to none, improves forecast precision for future CPs by 40% (decrement in variance of forecast error), and 2 CPs improve it by 67%. There is also an increase in forecast accuracy (decrement in mean of forecast error) as the number of CPs used increases. After only 2, forecast accuracy and precision are as good as theoretically possible. Moreover, information from CPs is far more valuable for forecasting than that from observable patient features-sex, age, and the like; use of all the latter information does not improve accuracy and precision as much as only 1 CP.


Assuntos
Preparações Farmacêuticas/sangue , Adulto , Teorema de Bayes , Digoxina/sangue , Tratamento Farmacológico , Humanos , Cinética , Modelos Biológicos
10.
Medicine (Baltimore) ; 64(4): 228-43, 1985 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-4010500

RESUMO

We present 11 patients with immunotactoid glomerulopathy, a new syndrome characterized clinically by proteinuria (11/11), microscopic hematuria (9/11) and hypertension (9/11). The patients consisted of six females and five males, aged 25 to 59 years (mean, 44.6). Proteinuria was the presenting feature and the reason for renal biopsy in all patients. The diagnosis of immunotactoid glomerulopathy was established at renal biopsy by the presence of glomerular extracellular microtubules composed of immune reactants. All the biopsies studied by immunofluorescence (10 cases) had glomerular deposits of IgG and C3. In three biopsies studied with IgG subclass specific antisera, only one patient had monoclonal immunoglobulin deposits (IgG3 kappa). In six cases the glomerular deposits were analyzed for light chains. In three the deposits contained kappa only, and three consisted of both kappa and lambda. In two cases the immune aggregates were confined to the mesangium, and in the remaining eight cases, the deposits were present in the mesangium and the glomerular basement membranes. Electron-dense deposits composed of microtubules were present in the same distribution within the glomerulus as the immune reactants. The microtubules had a uniform diameter in each biopsy, but they varied in size from case to case. They were approximately the same size in eight cases (mean, 22.3 +/- 3 [SD] nm). Three cases had much larger microtubules: 34.2 nm, 35.4 nm, and 48.9 nm in diameter. Although the 22.3-nm microtubules resembled amyloid in their appearance, glomerular distribution and random orientation in the tissue, they were more than twice the diameter of amyloid (8.9 nm), and Congo red and thioflavin T stains for amyloid were negative. Similar microtubular structures have been described in patients with cryoglobulinemia, SLE and paraproteinemia, but these diseases were excluded in our patients on clinical, serologic and in some cases histologic grounds. More important, none of our patients had clinical or histochemical evidence of amyloidosis, an entity which may be confused with immunotactoid glomerulopathy on a morphologic basis. Follow-up, from 22 to 94 months (mean, 52.6) was obtained in all 11 patients, and 2 clinical courses were noted. Six patients had progressive deterioration of renal function, with five requiring dialysis. This group had severe hypertension (4/6) and nephrotic-range proteinuria (5/6) at some point in their course. The remaining five patients with stable renal function had proteinuria of less than 2.0 g/24 hr in most cases (4/5), and none had severe hypertension. This dichotomy correlated with the distribution of immunotactoids.(ABSTRACT TRUNCATED AT 400 WORDS)


Assuntos
Nefropatias/patologia , Glomérulos Renais/patologia , Adulto , Amiloidose/patologia , Membrana Basal/ultraestrutura , Creatinina/sangue , Crioglobulinas/análise , Feminino , Mesângio Glomerular/patologia , Mesângio Glomerular/ultraestrutura , Hematúria/patologia , Humanos , Glomérulos Renais/ultraestrutura , Masculino , Microscopia Eletrônica , Microscopia de Fluorescência , Microtúbulos/ultraestrutura , Pessoa de Meia-Idade , Proteinúria/patologia
11.
Mech Ageing Dev ; 59(1-2): 139-52, 1991 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-1890878

RESUMO

A periodic pattern was discovered among the relative number of deaths per year for the major age-related diseases in humans. This pattern was observed among 178 causes-of-death composed of male and female. White (U.S.A.), Black (U.S.A.) and Japanese (Japan) populations. Both descriptive (Fourier transform) and statistical analysis procedures revealed evidence that the pattern resulted from the presence of an underlying power progression between disease prevalences, with a factor of approximately 2.0 between sizes. This periodicity was highly unlikely to have occurred by chance (P much less than 0.01). The presence of such a power progression suggests that the sizes of the various fractions of the total population, that are afflicted with these mortal diseases, are determined by forces intrinsic to the population and probably result from a common mechanism.


Assuntos
Mortalidade , Fatores Etários , Interpretação Estatística de Dados , Feminino , Análise de Fourier , Humanos , Japão/epidemiologia , Masculino , Periodicidade , Estados Unidos/epidemiologia
12.
Mech Ageing Dev ; 43(3): 239-57, 1988 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-3205061

RESUMO

The mortality kinetics of white humans of the United States were examined for 25 different age-related causes of death (22 male, 21 female). The survivorship distributions for these diseases clustered into groups, as defined by their position on the time axis. When the survivorship curves were linearized, by plotting as log(-log S(t] vs. log t, this clustering was easily identified as well-defined intersections among the lines separated by 2-year intervals. The four largest groups had intersections at approximate time values of 101, 99, 95, and 93 years, with a small group having an intersection at 97 years. The distribution of diseases among the intersections was not random but was related to sex and disease type. The two-parameter Weibull and GDCP (Gamma Distribution raised to a Combinatoric Power) functions were fit to the individual cause of death survivorship curves and yielded parametric values for the shape (slope) and median time to death. These two parameters varied with disease type and exhibited a positive, linear regression. The regression slope between the shape (alpha) and time (tau m) parameters of the GDCP was also equal to approximately 2 years. This suggested to us that the 2-year intervals in the median times of death with integral changes in the shape parameter and the 2-year time interval between the survivorship clusters may both arise from a similar process involving integral numbers of discrete steps.


Assuntos
Fatores Etários , Mortalidade , Biometria , Feminino , Humanos , Masculino , Probabilidade , Análise de Regressão , Fatores Sexuais , Estados Unidos
13.
Mech Ageing Dev ; 69(1-2): 1-31, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8377524

RESUMO

The Gompertz and Weibull functions are compared with respect to goodness-of-fit to human mortality distributions; ability to describe mortality curve intersections; and, parameter interpretation. The Gompertz function is shown to be a better descriptor for 'all-causes' of deaths and combined disease categories while the Weibull function is shown to be a better descriptor of purer, single causes-of-death. A modified form of the Weibull function maps directly to the inherent degrees of freedom of human mortality distributions while the Gompertz function does not. Intersections in the old-age tails of mortality are explored in the context of both functions and, in particular, the relationship between distribution intersections, and the Gompertz ln[R0] versus alpha regression is examined. Evidence is also presented that mortality intersections are fundamental to the survivorship form and not the rate (hazard) form. Finally, comparisons are made to the parameter estimates in recent longitudinal Gompertzian analyses and the probable errors in those analyses are discussed.


Assuntos
Biometria , Modelos Estatísticos , Mortalidade , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento , Criança , Pré-Escolar , Interpretação Estatística de Dados , Feminino , Humanos , Lactente , Recém-Nascido , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Modelos Biológicos
14.
Mech Ageing Dev ; 64(1-2): 149-60, 1992 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1630153

RESUMO

The dying off of human population cohorts due to different age related diseases rigorously follows stochastically derived rules. The existence of such rules suggests a common, fundamental mechanism for human mortality. We show here, by a simple quantitative analysis, that the progressive loss with age of genetic triplet code information (anticodons) in body cells, as described by the statistics of extremes in order theory, serves as such a mechanism.


Assuntos
Longevidade/genética , Mortalidade , Biossíntese de Proteínas , Adulto , Idoso , Envelhecimento/genética , Sequência de Aminoácidos , Anticódon/genética , Sequência de Bases , DNA/genética , Humanos , Pessoa de Meia-Idade , Modelos Genéticos , Dados de Sequência Molecular
15.
Mech Ageing Dev ; 40(3): 223-41, 1987 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3431163

RESUMO

We propose a new mathematical function for the analyses of age-related human deaths due to single causes. Like the earlier Gompertz and power law functions, it is a two parameter function. Unlike them, one of the parameters is an integer in the range of 5-13. The function is the integral gamma distribution raised to a combinatoric power (GDCP). The function has a deep relation to the power law, and this explains the past successes of the power law. The GDCP function generates highly accurate distributions for ages at death due to specific diseases, and also the means and variances for the distributions. It is possible now to assign unambiguously an integer to each cause of death. In model systems, the alpha integers are the number of "events" necessary to commit the organism to death. Different diseases with the same integer have the same age distribution at death. The major remaining problem is the relative sizes of the populations dying of each single cause. The solution to this must be model derived. The analysis of 24 single causes of death for males and females in the U.S.A., white population over the years 1968-1978 show: (1) the alpha integer is eight for almost all digestive organ carcinomas in both males and females; (2) cancers at other sites have various values for alpha; and (3) for vascular diseases females have alpha integers higher by one or two than males. If the combinatoric power is multiplied by a constant then the second number in the function, tau, the time constant, which is different for each disease, takes on an approximately constant value, which we call the "characteristic age" of the species. Thus, with one number, the "characteristic age" and the nine integers, we can predict, using the GDCP function, the relevant distributions of deaths due to all the different diseases.


Assuntos
Modelos Biológicos , Mortalidade , Fatores Etários , Humanos , Processos Estocásticos
16.
Mech Ageing Dev ; 7(5): 335-49, 1978 May.
Artigo em Inglês | MEDLINE | ID: mdl-148544

RESUMO

Any thermodynamic study of aging and death in laboratory mammals is dependent on techniques which would allow for the chronic manipulation of the core body temperature of these organisms. Accordingly, the hypothermic response after parenteral administration of chlorpromazine, L-dopa, reserpine, and p-chlorophenylalanine was investigated in the mouse. Mice injected at 24 hour intervals with chlorpromazine exhibited a diminished response (tolerance) with repeated administration. The degree of induced hypothermia and resistance to tolerance was greater in male mice than in femal mice. L-dopa was unable to potentiate chlorpromazine hypothermia but did evoke a non-adapting hypothermic response when administered alone. Reserpine also evoked a non-adapting hypothermia. Further, animals treated with small doses of reserpine exhibited an increasing response with repeated injections. p-Chlorophenylalanine induced hypothermay that became intermittent with successive administration. The results presented here indicate that both reserpine and L-dopa would be of value as hypothermic agents in long term investigations.


Assuntos
Hipotermia/induzido quimicamente , Levodopa , Reserpina , Adaptação Fisiológica/efeitos dos fármacos , Envelhecimento , Animais , Clorpromazina , Sinergismo Farmacológico , Feminino , Fenclonina , Masculino , Métodos , Camundongos , Camundongos Endogâmicos ICR , Fatores Sexuais , Termodinâmica
17.
Mech Ageing Dev ; 18(1): 33-45, 1982 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7062787

RESUMO

The kinetics of heat-induced lysis of a population of sheep red blood cells over the temperature range 42 degrees - 56 degrees C are shown to be similar in form to the survivorship curves of multicellular organisms and are describable by the power law function,--(1/N)(dN/dt) = At(n-1). The A parameter of the power law function is examined in this model system in an attempt to show its relationship to molecular events. Arrhenius-type plots of the A parameter are different for old populations of red blood cells compared to young populations. The plot for the old cells shows a high energy transition at 50 degrees C. For the young cells an activation enthalpy of 232 kcal/mole is obtained with no transition occurring at 50 degrees C. The parameter l/tau, defined as A1/n, is more directly related to the molecular basis of the temperature dependence of the lysis kinetics. The Arrhenius plots of 1/tau give activation enthalpies of 42.8 and 40.4 kcal/mole for young and old cells, respectively, and activation entropies of 57.6 and 50.3 cal/mole per degree. These activation enthalpies and activation entropies appear to be in accord with a compensation law for these qualities for protein denaturation, and support the suggestion that protein denaturation is the rate-limiting step in the lysis of sheep red blood cells.


Assuntos
Eritrócitos/fisiologia , Envelhecimento , Animais , Envelhecimento Eritrocítico , Temperatura Alta , Humanos , Cinética , Matemática , Modelos Biológicos , Desnaturação Proteica , Ovinos , Termodinâmica
18.
Mech Ageing Dev ; 55(3): 255-91, 1990 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2232917

RESUMO

Human mortality distributions were analyzed for 29 disease-specific causes-of-death in male and female, White (U.S.A.), Black (U.S.A.) and Japanese (Japan) populations, constituting a total of 162 separate cohorts. For each cohort distribution, the curve moments and the parameter values for fits to model equations were determined. The differences between cohort distributions were characterized by two degrees of freedom, related to distribution position and shape, respectively. A form of the Weibull function was shown to contain two parameters that mapped to these two degrees of freedom. Parametric analysis on 136 best-fitting cohorts yielded periodic clustering in the set of values for both Weibull parameters as quantitated using a Fourier transform method and an independent statistical method. This periodicity was unlikely to have occurred by chance (P less than 0.01). We have combined these results into a Law of Mortality, based on a Weibull function containing only integer parameters and constants, which is valid for all human age-related disease mortality. We show that the life expectancy differences between races and sexes is completely described by this formalism. We conclude that human mortality is controlled by discrete events, which are manifested in the appearance of only allowed mortality curve shapes and positions.


Assuntos
Mortalidade , Taxa de Sobrevida , Adulto , Negro ou Afro-Americano/estatística & dados numéricos , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Causas de Morte , Análise por Conglomerados , Etnicidade/estatística & dados numéricos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estados Unidos , População Branca/estatística & dados numéricos
19.
J Immunol Methods ; 150(1-2): 77-90, 1992 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-1613260

RESUMO

Six monoclonal and two polyclonal antibodies to fluorescein (FLU) were affinity purified and immobilized on Immulon 2 polystyrene as capture antibodies (CAbs): (a) by passive adsorption at pH 9.6, (b) via a streptavidin bridge to a biotinylated carrier molecule, and (c) via an antiglobulin which had been previously adsorbed passively to the polystyrene. Data show that less than 3.0% of the binding sites of monoclonal CAbs and approximately 5-10% of those of polyclonal CAbs were capable of capturing antigen (FLU4.2-BSA) after passive adsorption. Immobilization of CAbs via an antiglobulin or a streptavidin bridge, resulted in the preservation of antibody binding sites to greater than 70% for some monoclonals although immobilization via the streptavidin bridge resulted in the highest number of functional sites/well. The data presented are consistent with studies on other adsorbed proteins which demonstrate that passive adsorption on polystyrene results in the loss of protein function. Furthermore, these data show that generally less than half of the binding sites of antibodies available in solution are available after solid-phase immobilization even when non-adsorptive methods are employed. Some polyclonal anti-FLU also have lower average avidity following passive adsorption compared with CAbs immobilization via a streptavidin bridge. Immunochemical studies revealed that adsorbed polyclonal-CAbs performed like monoclonals when tested with multivalent antigens (FLU10-IgA) but in an expected heterogeneous manner in Scatchard plots when tested using univalent FLU-insulin. This observation implied cross-linking of immobilized CAbs by the multivalent antigen. Because only 5-10% of adsorbed polyclonal CAbs are active, the survivors must be non-randomly distributed in clusters to explain the cross-linking. This was confirmed by scanning electron microscopy which gave rise to the hypothesis that antibodies which retain activity after adsorption, are those present in clusters, i.e., the functional adsorbed CAb is an antibody cluster. Data presented in this report on the behavior of adsorbed CAbs, and reviewed from the work of others for various adsorbed proteins, indicate that the method of passive adsorption at pH 9.6, which is widely used in popular microtiter ELISAs, and which has in many ways revolutionized immunoassay, is a method of protein denaturation. Assayists that utilize passive adsorption of proteins on hydrophobic supports as part of their research need to be cognizant of this phenomenon, while inventors of immunoassay should develop alternative methods of immobilization which do not destroy 90% of the functional activity of solid-phase reactant.


Assuntos
Anticorpos/química , Imunoensaio/métodos , Poliestirenos , Adsorção , Animais , Anticorpos/imunologia , Reações Antígeno-Anticorpo , Sítios de Ligação de Anticorpos , Microscopia Eletrônica de Varredura
20.
Hum Pathol ; 17(11): 1151-7, 1986 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-3533754

RESUMO

Ten cases of duodenal paraganglioma were studied by conventional histologic and immunocytochemical techniques at both light and electron microscopic levels. Histologically, mixtures of epithelial, ganglion, and spindle cells were seen. In all of the cases immunoreactivity for neuron-specific enolase (NSE) and protein gene product (PGP) 9.5 was seen in each component. Pancreatic polypeptide immunoreactivity was detected in eight cases, mainly in epithelial cells. Somatostatin immunoreactivity was present in epithelial and ganglion cells in nine cases. In seven cases immunoreactivity for neurofilaments, a marker for neurons, was seen in ganglion and spindle cells. However, immunoreactivity for chromogranin, a protein found in endocrine storage granules, was found in only two cases, and the staining was confined to well-granulated epithelial cells. The spindle cells were immunostained only for neuronal markers, NSE and neurofilaments, and the glial marker S-100 protein.


Assuntos
Neoplasias Duodenais/patologia , Paraganglioma/patologia , Neoplasias Duodenais/metabolismo , Feminino , Histocitoquímica , Humanos , Técnicas Imunológicas , Masculino , Pessoa de Meia-Idade , Paraganglioma/metabolismo
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