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PubMed1986

Mechanisms of tumor cell capture by activated macrophages: evidence for involvement of lymphocyte function-associated (LFA)-1 antigen.

The lymphocyte function-associated (LFA)-1 molecule is expressed on certain populations of macrophages that have an augmented capacity to capture tumor cells. Accordingly, we analyzed the role of LFA-1 in the establishment of such cell-cell interactions. F(ab')2 fragments of the M17/4, anti-LFA-1 monoclonal antibody (MAb) inhibited the interaction between activated macrophages and tumor cells by up to 80% in a dose-dependent manner. The anti-LFA-1 MAb reduced (between 55 to 79%) the number of P815, LSTRA, or EL-4 tumor cells bound to trypsin-sensitive structures on bacillus Calmette Guerin activated macrophages. The inhibition appeared selective, because a F(ab')2 fragment of anti-Mac-1 did not inhibit such binding. Inhibition of tumor cell capture could be observed as soon as 15 min after the onset of the cell-cell interaction between activated macrophages and tumor cells. Optimal inhibition occurred when both tumor targets and macrophages were precoated with the MAb. Although P815, LSTRA, EL-4, and BW5147 tumor cells all expressed LFA-1, only the first three but not BW5147 cells were bound by activated macrophages. Furthermore, endotoxin-pulsed macrophages elicited by thioglycollate broth expressed the LFA-1 antigen but did not exhibit selective tumor cell capture. Finally, anti-LFA-1 inhibited the development of weak into strong binding. Taken together, the results suggest that LFA-1 molecules can participate in the interaction between activated macrophages and neoplastic cells.

Animals↗

PubMed1986

Detection of adenovirus hexon using monoclonal antibodies for antigen capture in ELISA.

The feasibility of using monoclonal antibodies to capture specific viral polypeptides in double monoclonal antibody (MAb) sandwich ELISA has been demonstrated. Ten MAbs with different reactivity patterns were used for antigen capture and four of them were labelled with horse radish peroxidase and used for the detection of specifically bound hexon antigen and for the determination of the lowest reacting hexon concentrations. Differences have been found in the effectiveness of the different MAbs used for capturing or detecting the antigen. Two assay systems (MAbs 1A3/1A3 and H12/1A3), which were the most sensitive for the hexon types studied could be useful for detection of the adenovirus hexons. Assay system MAb 2D1/2A1 and several combinations of MAb 2B2 proved to be specific for subgenus C.

Adenoviruses, Human↗

PubMedDate not supplied

Measurement of hertzian waves capture at body surface in patients with traumatic paraplegia.

Using an original method--the Biohertzmetry--the level of hertzian waves capture at body surface was measured in 20 patients with traumatic paraplegia. A statistically significant decrease of the hertzian waves capture level in the toes in comparison with the proximal area has been noted in 12 patients with complete spinal cord lesion. In patients presenting an open or cicatricial decubitus ulcer, at scar level, in the surrounding skin area with modified colour--and even in a contiguous few millimeters large skin strip normally coloured,--a marked decrease of the level of hertzian waves capture in comparison with the healthy skin ares situated off the decubitus ulcers has been pointed out. Thus, the method used permitted to reveal the alterations of the tissue trophicity--including those undetectable with the naked eye--and to make an estimation of the degree of mortification of the tissues and a delimitation of the reduced trophicity area.

Absorption↗

PubMed1989

Comparison of four different antigen-capture assays for the detection of human immunodeficiency virus antigen (HIV-Ag).

Three enzyme immunoassays (EIA), two polyclonal and one monoclonal, and one polyclonal radioimmunoassay (RIA) for the detection of human immunodeficiency virus antigen (HIV-Ag) have been evaluated and compared. The three EIAs had similar sensitivity in detecting HIV viral lysate and were more sensitive than the RIA, which was the only assay with a one-step probing-detection format. However, the EIA that used a monoclonal anti-p24 as the capturing reagent was unable to detect any of the serial supernatant samples of a positive viral culture from an HIV-infected patient. Only the two polyclonal, non-p24-restricted assays were able to detect an unusual expression of HIV-Ag in the serum of an acute HIV-infected patient. Overall, the sensitivity of HIV-Ag capture assays was enhanced when (a) the capture antibody was polyclonal rather than monoclonal, (b) the polyclonal antibody was broad rather than p24-restricted, and (c) the probing-detecting procedure was in a two-step format rather than one-step format. In addition, the use of neutralizing assays to confirm the results was absolutely necessary.

Antibodies, Monoclonal↗

PubMed1988

Boron neutron capture therapy of a murine melanoma.

Boron neutron capture therapy has been carried out on BALB/c mice carrying the Harding-Passey melanoma s.c. on the thigh. p-Boronophenylalanine (BPA), a boronated analogue of natural melanin precursors, was used to target boron selectively to melanoma. BPA was administered to the mice either via i.p. injection or p.o. by intubation. 10B concentrations in tumor ranged from 15 to 40 ppm depending on the route and timing of administration. Irradiations with a predominantly thermal neutron beam were performed at the Brookhaven Medical Research Reactor. In the absence of BPA, only transient tumor growth delays were observed at low neutron fluences. At 5 x 10(16) n/m2, 4 of 22 tumors irradiated in the absence of BPA underwent long-term tumor growth control; after p.o. administration of BPA (40 ppm 10B in the tumor), the fraction of tumors controlled increased to 11 of 19. The average dose to the tumor in the latter group was 17.8 Gy, of which 14.8 Gy were due to the 10B neutron capture reaction. The biological effectiveness of the absorbed dose from the neutron capture reaction, at the 50% tumor control level, was found to be twice that of 100 kVp X-rays.

Animals↗

PubMed1986

Constant-parameter capture-recapture models.

Jolly (1982, Biometrics 38, 301-321) presented modifications of the Jolly-Seber model for capture-recapture data, which assume constant survival and/or capture rates. Where appropriate, because of the reduced number of parameters, these models lead to more efficient estimators than the Jolly-Seber model. The tests to compare models given by Jolly do not make complete use of the data, and we present here the appropriate modifications, and also indicate how to carry out goodness-of-fit tests which utilize individual capture history information. We also describe analogous models for the case where young and adult animals are tagged. The availability of computer programs to perform the analysis is noted, and examples are given using output from these programs.

Aging↗

PubMed1987

The Monte Carlo simulation of the biological effect of the 10B(n, alpha)7Li reaction in cells and tissue and its implication for boron neutron capture therapy.

The energy deposition in the nucleus of cells exposed to the 10B(n, alpha)7Li neutron capture reaction has been calculated and compared to the measured biological effect of this reaction. It was found that a considerable distribution of hit sizes to the nucleus occurs. The comparison of hit size frequency with the observed survival indicates that not every hit, independent of its size, can lead to cell death. This implies the existence of a hit size effectiveness function. The analysis shows that the location of boron relative to the radiation-sensitive volume of the cell is of great importance and that average dose values alone are of limited use for predicting the biological effect of this reaction. Boron accumulating in the cell nucleus is much more efficient in cell killing than the same amount of boron uniformly distributed; its presence in one cell, however, has little effect on its neighboring cells in a tissue. When boron is present on the cell surface of a tissue (as presumably delivered by antibodies), its cell-killing effect is greatly reduced compared to that in uniform distribution. However, in this case much of the dose to one cell comes from neutron capture reactions occurring on the surface of its neighbor cells. These data have implications for the choice of boron carries in neutron capture therapy. The mathematical analysis carried out here is similar to that proposed recently for low-level exposure effects of radiation, taking mutation and/or carcinogenesis as biological effects. The results here show that high-level exposure to high-LET particles (resulting in cell killing) should be treated in an analogous manner.

Animals↗

PubMed1985

Transperitoneal migration and ovum capture in rabbits.

It is not fully understood how eggs are captured by the fallopian tube. The close proximity of tube and ovary, and the movements of the fimbria across the ovarian surface during ovulation, are believed to contribute to ovum pickup. We studied the efficiency of ovum capture when contact between fimbria and ovary is prevented and the extent to which ovum transmigration may contribute to fertility. Unilateral right oophorectomy was performed in 55 rabbits, which were divided into three groups: in Group A, the contralateral oviduct was left intact; in Group B, the ampulla of the contralateral oviduct was occluded; in Group C, contralateral total salpingectomy was performed. None of the rabbits in Group A conceived on the oophorectomized side. Seven of 19 animals became pregnant in Group B and 15 of 18 conceived in Group C. The results indicate that direct fimbrial-ovarian contact is not essential for ovum capture, and that ovum transmigration could contribute to fertility.

Animals↗

PubMed1983

Robust estimation of population size in closed animal populations from capture-recapture experiments.

In this paper the problem of finding robust estimators of population size in closed K-sample capture-recapture experiments is considered. Particular attention is paid to models where heterogeneity of capture probabilities is allowed. First, a general estimation procedure is given which does not depend on any assumptions about the form of the distribution of capture probabilities. This is followed by a detailed discussion of the usefulness of the generalized jackknife technique to reduce bias. Numerical comparisons of the bias and variance of various estimators are given. Finally, a general discussion is given with several recommendations on estimators to be used in practice.

Animals↗

PubMed1981

An electron-capture gas chromatographic assay for naltrexone in biological fluids.

The electron-capture gas chromatography assay for naltrexone is an adaptation of the method published originally by Sams and Malspeis (1). The current methodology, described in detail, consists of an extraction procedure, derivatization to form an electron-capturing triester, and gas chromatography using an OV-17 column. Extraction efficiencies indicate that either benzene or 0.25% butanol in cyclohexane used as the organic phase yields maximal extraction of naltrexone and minimal extraction of most naltrexone metabolites. Methylene chloride, on the other hand, yields an optimal combination of clean chromatograms and high extraction efficiencies for both naltrexone and its metabolites. Derivatization with either heptafluorobutyric anhydride or pentafluoropropionic anhydride together with a basic catalyst yields a triester derivative. Use of an OV-17 chromatographic column with electron-capture detection permits assay of naltrexone specifically with respect to known metabolites. One minor metabolite, 2-hydroxy-3-O-methyl-beta-naltrexol could interfere with naltrexone quantitation if present in sufficient quantities. This interference could readily be detected if it were to occur. Data on the reproducibility of this assay procedure indicate that it is sensitive to a concentration of 0.25 ng/ml plasma.

Chromatography, Gas↗

PubMed1981

Haemodynamic effect of the suppression of ventricular tachycardia by atrio-ventricular captures.

In 10 anaesthetized open chest dogs, blood pressure, electrogram from the left auricular appendage or right atrium, peripheral ECG and cardiac output were recorded. Ventricular tachycardia was produced with aconitine and then suppressed by inducing atrial fibrillation or flutter-fibrillation either with aconitine or with electrical stimulation. After the capture of the ventricles by the supraventricular impulses, a haemodynamic improvement took place. This improvement is attributed to: I) beat to beat changes in the length of the cardiac cycles, whereby intermittent strong beats arise; II) restoration of the normal ventricular activation path and time course; III) the active contribution of properly timed atrial contractions, when present. The improvement was more evident when, after the capture, the ventricular rate was lower than during the ventricular tachycardia, because of a longer period available for the ventricular filling. It is believed that the reduction of the ventricular rate immediately after the capture is due to the suppression of the activity of the ventricular ectopic focus by the concealed conduction of high rate impulses coming from the atria.

Animals↗

PubMed1994

A general theory for modeling capture-recapture data from a closed population.

A general theory for estimating the size of a closed population from multiple-recapture data is presented. This theory is easily extended to open population models for multiple-recapture data. Estimation is based on a log-linear model developed for modeling dependent capture-recapture data when capture probabilities vary temporally with behavioral response and are heterogeneous among animals. Models for complete capture history data are developed along with the first log-linear models for removal data. The maximum likelihood estimator of the model parameters along with the estimated covariance matrix are presented.

Animal Identification Systems↗

PubMed1995

Histochemistry of sarcoplasmic reticulum Ca-ATPase using dysprosium as capturing reagent.

This report describes the development of a histochemical method for the demonstration of sarcoplasmic reticulum Ca-ATPase activity in cross-sections of skeletal muscle. The demonstration of sarcoplasmic reticulum Ca-ATPase activity is complicated by the fact that capturing reagents for phosphate inhibit the enzyme. We present a minimal model for heavy-metal-phosphate precipitation reactions which gives a theoretical description of the effect of enzyme inhibition on the rate of phosphate precipitation in the section. The model indicates that the choice of capturing reagent is crucial: whether or not ATPase activity can be demonstrated depends mainly on the inhibition constant and the solubility product of the phosphate salt of the capturing reagent (but also on a fairly large number of other factors). All lanthanides tested can be used to demonstrate sarcoplasmic reticulum Ca-ATPase activity, but dysprosium results in the highest staining intensity. This suggests that dysprosium inhibits sarcoplasmic reticulum Ca-ATPase to a lesser degree than the other lanthanides and/or the solubility product of its phosphate salt is smaller. As an example, the method is used to investigate the effect of thyroid hormone on sarcoplasmic reticulum Ca-ATPase activity in individual fibres of the rat soleus muscle.

Animals↗

PubMed1977

Capture myopathy in Elk in Alberta, Canada: a report of three cases.

Acute capture myopathy was diagnosed in 3 elk (Cervus canadensis). In 2 of the elk, hindlimb lameness developed within 10 days of capture. Clinical signs were not observed in the third elk, which was found dead 7 days after its capture. Elks 1 and 2 were euthanatized and all 3 animals were necropsied. In elks 1 and 2, rupture of the semi-membranosus muscle was associated with massive hemorrhage and swelling. Microscopic findings included hemorrhage, edema, myofibril fragmentation, and evidence of attempted muscular regeneration. In elk 3, several of the large muscles of the hindlimbs as well as the biceps brachii muscles of the forelimbs appeared pale, dry, and friable. Except for lack of hemorrhage and edema, microscopic findings in this elk were similar to those of elks 1 and 2.

Alberta↗

PubMed1976

[Studies of Yersinia pestis in wild animals captured in Ankara, Konya and Nevsehir].

No Yersinia pestis could be isolated, by culturing and by inoculations to 1212 guinea-pigs and 150 mice; from 623 citellus, 41 Mus musculus, 55 Microtus, 442 Meriones, 70 Rattus rattus, 56 turtle, 89 hare, 1 hamster, 1 hedgehog, 1 sea snake, altogether 790 dead, 589 alive, i.e. 1379. wild animals captured in Ankara, Konya (Karapinar), Urfa (Akçakale) and in Nevşehir. In 141 sera taken from citellus captured alive, and in 174 sera taken from guinea-pigs inoculated with spleen, liver and kidney suspensions of wild animals, 1/20 - 1/80 agglutination titers (one of the sera from a guinea-pig inoculated with hare organ suspension) were obtained. These findings, probably were due to Yersinia pseudotuberculosis, because this organism was isolated from citellus captured in Ankara and Konya.

Animal Population Groups↗

PubMed1997

Capturing clinical reports in a large academic medical center: feeding a central patient data repository.

Clinical reports, notes, and other narratives are highly used components in the patient record. Unfortunately, the methods by which these reports are generated are as diverse as the fiscal autonomy of academic clinical departments in a university-based health science center. In this paper, we report on electronically capturing clinical reports, notes, and other text fragments from several hospital sources and many outpatient clinics. The purpose of the capture is to feed the ACIS (Advanced Clinical Information System) central patient data repository that is in use at the University of Utah Health Sciences Center (UUHSC). A survey conducted in early 1994 indicated that about 917,150 reports were generated per year at UUHSC representing about 1.2 million pieces of paper, occupying about 2.3 gigabytes of storage. The most crucial problem encountered in capturing the reports was linking them to the proper patient. Systems that had functioning and well-maintained admit-discharge-transfer (ADT) information performed well, but systems that relied on the human dictator to identify patients, produced patient linkage errors. In our open loop telephone dictation systems this error rate averaged between 6 and 10%. Subsequent to the wide-spread availability of clinical reports on ACIS, this error rate dropped to 3-5%, presumably due to increased demand for on-line availability of this information. From clinical secretaries who use their word processor to create the clinical reports, the linkage error rate was < 1% due to the use of our Advanced Text Upload (ATU) utility. The clinical text component in ACIS contributed significantly to the success of a JCAHO site visit in December 1995.

Academic Medical Centers↗

PubMed1997

Detection of Paragonimus heterotremus in experimentally infected cat feces by antigen capture-ELISA and by DNA hybridization.

An antigen capture enzyme-linked immunosorbent assay (antigen capture-ELISA) and DNA hybridization technique were developed and evaluated for their application in the detection of Paragonimus heterotremus infection in experimentally infected cats. An IgG fraction prepared from serum of a rabbit immunized with P. heterotremus excretory-secretory (ES) products was used as the capture antibody. An IgG1 monoclonal antibody specific to the 22- and 31.5-kDa ES products of P. heterotremus was used as the antigen probe. As little as 0.24 ng of the ES products could be detected by this technique. A specific P. heterotremus DNA probe derived from the P. heterotremus genomic DNA library containing 1,500 base pairs was used in a dot-blot hybridization assay for the detection of parasite DNA. The radioactively labeled probe could detect DNA released from as few as 2 P. heterotremus eggs. Both ELISA and DNA hybridization were found to have 100% specificity, with sensitivities of 73.7% and 100%, respectively.

Animals↗

PubMed1996

[Nested polymerase chain reaction (PCR) and multiple cloned antibody capture PCR for the examination of serum hepatitis B virus DNA in negative hepatitis B surface antigen patients suffering from liver diseases].

In order to find out rapidly the causes of the liver diseases suffered by patients with negative hepatitis B surface antigen (HBsAg), nested polymerase chain reaction (PCR) and multiple cloned antibody capture PCR techniques were established to examine serum hepatitis B virus (HBV) DNA. By using both techniques along with the examination of hepatitis C virus (HCV) infection, the causes of chronic liver diseases with negative HBsAg were studied. It is found that nested-PCR can increase the sensitivity of single PCR more than 1,000 fold and multiple cloned antibody capture-PCR can detect concentration of HBV DNA as low as 0.1-0.01 pg/L. HBV DNA positive patients were found in 45.5%, 30.8%, 13.3% and 100% respectively of the patients suffering from liver cirhosis with negative HBsAg (group A, 22 cases), chronic hepatitis with negative HBsAg (group B, 13 cases), normal subjects with negative HBsAg and positive hepatitis B core antibody (HBcAb, group C, 30 cases) and liver cirhosis with positive HBsAg and negative HBeAg (group D, 12 cases). HBV DNA can be also found in the serum of HBsAb positive patients and subjects supposed to be healthy, 81.8% and 53.8% of the patients were infected with HBV and/or HCV in group A and group B respectively. All these results suggest that nested-PCR and multiple cloned antibody capture-PCR are rapid and highly sensitive methods for detection of serum HBV DNA. HBV infection is an important cause of chronic liver diseases in patients with negative HBsAg. The causes of most of the HBsAg-negative chronic liver diseases are related with infection of viruses. The clinical significance of serum HBsAb in naturally infected patients should be reconsidered.

Adult↗