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Biomedical subjects

M M Garcia

Publications and source records attributed to M M Garcia.

At least 73 records · Page 4Linked to original sources
PubMed1990

Protein G-based enzyme-linked immunosorbent assay for anti-MPB70 antibodies in bovine tuberculosis.

MPB70 is a highly species specific protein which is secreted from Mycobacterium bovis during culture. To investigate whether antibodies against MPB70 can be used as an indicator of infection with M. bovis, an enzyme-linked immunosorbent assay was developed, based on the use of biotinylated protein G, to provide a common indicator for antibody formation in different species. During experimental infection with M. bovis in cattle, a characteristic pattern of anti-MPB70 antibody production was observed with an initial flat plateau followed by a marked rise 18 to 20 weeks after infection. Skin testing with bovine tuberculin purified protein derivative (PPD), which was shown to contain antibody-reactive MPB70, was a potent stimulator of antibody production in infected animals. In experimentally infected cattle, we observed an inverse relationship between antibody activity and delayed-type hypersensitivity skin test reactions. In natural M. bovis infections, skin testing with PPD was also a potent stimulator of anti-MPB70 formation. Comparison between the enzyme-linked immunosorbent assay for antibodies to MPB70 and that for antibodies to the widely cross-reacting M. bovis BCG antigen 85B in animals with M. bovis, Mycobacterium avium, Mycobacterium paratuberculosis, and Corynebacterium pseudotuberculosis infections showed that formation of antibody to MPB70 was highly specific for infection with M. bovis. The use of an MPB70-containing PPD preparation for skin testing followed by this anti-MPB70 assay is a highly specific indicator of M. bovis infection. Adjustment of the test conditions is expected to provide an increased sensitivity of the procedure for the diagnosis of natural M. bovis infections.

Animals↗
PubMed1989

Cellular localization of substance P- and neurokinin A-encoding preprotachykinin mRNA in the female rat brain.

To determine the locations of neurons in the rat brain expressing substance P and neurokinin A mRNA, we performed in situ hybridization with a radiolabeled cRNA probe that was complementary to alpha-, beta-, and gamma-preprotachykinin mRNA. Several types of controls indicated specificity of the labeling. Brain regions containing many labeled neurons include the anterior olfactory nucleus, layer II of the olfactory tubercle, the islands of Calleja, the nucleus accumbens, the caudate-putamen, portions of the amygdala and hypothalamus, the medial habenular nucleus, nuclei of the pontine tegmentum, several raphe nuclei, several portions of the reticular formation, and the nucleus of the solitary tract. Less frequent labeled neurons were also found in many other regions of the brain. These results extend many previous immunocytochemical studies of the locations of neurons containing immunoreactive substance P, neurokinin A, and neuropeptide K.

Animals↗
PubMed1989

Measurement of erythropoietin in anephric children. A report of the Southwest Pediatric Nephrology Study Group.

Serum erythropoietin (Ep) levels were measured using a highly sensitive radioimmunoassay in 69 children undergoing chronic dialysis; 31 were anephric, whereas 38 were non-nephrectomized (nephric). Twenty-nine normal children were studied as controls. Serum Ep levels in the anephric group were much higher than anticipated (mean 19.7 +/- 1.8 mU/ml), albeit significantly lower than those measured in normal children (mean 26.2 +/- 2.4 mU/ml, P less than 0.05), or in nephric children on dialysis (33.0 +/- 2.9 mU/ml, P less than 0.001). Anephric children on peritoneal dialysis (PD) had significantly (P less than 0.05) higher serum levels of Ep (22.7 +/- 2.4 mU/ml, n = 19) than anephric children on hemodialysis (HD) (15.1 +/- 2.3 mU/ml, n = 12). There was no significant difference between Ep levels in anephric patients dialyzed for less than or equal to 1 year (19.6 +/- 2.0 mU/ml, n = 20) compared with anephric patients dialyzed for more than 1 year (20.0 +/- 3.9 mU/ml, n = 11). Although serum Ep levels showed a tendency to increase with time after nephrectomy, the mean values for less than 3 months (14.7 +/- 1.9), 3 months-12 months (21.0 +/- 2.7), and greater than 12 months (21.6 +/- 6.0) were not significantly different from each other. This demonstration of relatively normal levels of serum Ep in anephric children suggests that extrarenal sites of Ep production are able to exert a significant response to severe anemia in patients who are devoid of renal parenchyma.

Adolescent↗
PubMed1988

Evaluation of the serological response of sheep in one flock to Mycobacterium paratuberculosis by crossed immunoelectrophoresis.

Sera from 74 sheep culled from one flock on the basis of performance and response to immunological tests for paratuberculosis or maedi visna were used to evaluate the serological response to a sonicated antigen of Mycobacterium paratuberculosis by crossed immunoelectrophoresis. A total of seven precipitating components was demonstrated. Four components (A,C,V,W) were detected in low frequency only with sera from animals with paratuberculosis while two components (X,Y) were detected in high frequency with sera from animals with or without paratuberculosis. One component (D) was observed in high frequency with sera from animals with paratuberculosis. The magnitude of the serological response to the D component as measured by crossed immunoelectrophoresis correlated well with bacterial load and generally agreed with the quantitative assessment by agar gel immunodiffusion. A development time for crossed immunoelectrophoresis of 24-72 hours after electrophoresis was required to achieve correlation with agar gel immunodiffusion.

Animals↗
PubMed1988

Characterization of an atypical biotype of Brucella abortus.

Brucella abortus strains were isolated from bovine tissue and milk samples from seven Ontario herds. The isolates were characterized by colonial morphology, requirement of CO2 for growth, lysis by Tbilisi phage, biochemical tests and agglutination in monospecific sera. They resembled B. abortus biotype 2 (on the basis of sensitivity to thionin and basic fuchsin) and biotype 4 (on the basis of agglutination with anti-Brucella "M" but not anti-Brucella "A" absorbed sera). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of these isolates and B. abortus biotypes 1, 2 and 4 showed similar profiles. Immunoblots with anti-A and anti-M absorbed sera showed different antigenic regions reacting with the specific sera and also confirmed that the atypical B. abortus isolates were serologically similar to biotype 4.

Animals↗
PubMed1987

Enzyme immunoassay for detection of Mycoplasma bovis antigens in bull semen and preputial washings.

A capture enzyme immunoassay was developed for the detection of Mycoplasma bovis antigens in bull semen or preputial washings. IgG prepared from rabbits immunised with M bovis was passively adsorped to 96-well polystyrene plates. This antibody captured M bovis antigens which were then detected by using an IgG preparation from an immunised cow and murine monoclonal antibody to the bovine L-chain conjugated with horseradish peroxidase. The sensitivity of the assay was approximately 200 colour changing units (ccu)/ml and the specificity was excellent in that other species of mycoplasma, ureaplasma or acholeplasma did not react. A blind study of bull semen experimentally contaminated with M bovis detected all specimens with more than 200 ccu/ml.

Animals↗
PubMed1987

Necrobacillary bronchopneumonia in a steer.

A one and one-half year old steer killed in a slaughterhouse had necrobacillary fibrinous bronchopneumonia with abscessation. Histologically, there were variably sized areas of coagulation necrosis in the lungs, thrombosis of pulmonary lymphatics, and fibrin deposits in the bronchioli and adjacent alveoli. Fusobacterium necrophorum in pure culture was isolated from the lung.

Animals↗
PubMed1987

Evaluation of gamma radiation levels for reducing pathogenic bacteria and fungi in animal sewage and laboratory effluents.

Sewage samples collected from animal wastes and from effluents at an animal disease laboratory were inoculated with known numbers of pathogenic organisms and subjected to various doses of gamma radiation from a 60Co source. Surviving test organisms were quantitatively determined by selective and enrichment techniques. The experiment was modeled as a quantal assay in which probit analysis was applied to obtain D10 values. The D10 value represents the irradiating dose required to reduce the population by 90%. The D10 value ranged from 13.4 krad for Campylobacter fetus to 156.6 krad for Streptococcus faecalis in animal sewage. However, the D10 value for the laboratory effluent was generally lower. Based on the estimated D10 values, the rating of the test organisms in decreasing order of radiosensitivity appeared as follows: Brucella abortus, Campylobacter fetus subsp. fetus, Campylobacter jejuni, Campylobacter coli, Campylobacter laridis, Mycobacterium fortuitum, Aspergillus fumigatus, Salmonella muenster, Candida albicans, Clostridium difficile and Streptococcus faecalis. If the D5 and D1 values were utilized, this listing would be only slightly altered.

Bacteria↗
PubMed1986

Vaccination studies for the control of campylobacteriosis in Jamaican cattle.

Following the first diagnosis of campylobacteriosis in Jamaican cattle a field study was undertaken to determine the pathogenicity of Campylobacter fetus subspecies venerealis Jam (Jamaican strain) and to evaluate the effectiveness of vaccination in controlling the disease. A total of 46 nonpregnant yearling heifers and four two-year-old bulls were used in two separate experiments. The results showed that C fetus subspecies venerealis Jam readily colonised the reproductive tract of susceptible heifers and persisted in some animals (68 per cent of unvaccinated and 33 per cent of vaccinated animals) for the duration of the experiment. Pregnancy was confirmed in 13 of 18 (72 per cent) culture-negative heifers but in only eight of 28 (29 per cent) of the heifers with two or more positive cultures. Vaccination appeared to be curative because 44 per cent of vaccinated heifers were cleared of infection whereas 85 per cent of unvaccinated, inoculated heifers remained infected for at least 17 weeks. Vaccination improved the fertility level of the infected heifers threefold. Infection was not established in vaccinated bulls used for breeding infected heifers.

Animals↗
PubMed1986

Isolation and characterization of cephalothin-susceptible Campylobacter coli from slaughter cattle.

In a recent meat survey, 10 of 13 (77%) Campylobacter coli isolates were susceptible to cephalothin. These organisms were isolated from nine slaughter cattle from eight meat packing establishments. All 10 isolates grew at 43 degrees C but not at 25 degrees C, were catalase and oxidase positive, and were susceptible to nalidixic acid (30 micrograms) and cephalothin (30 micrograms). The cultures were subsequently identified as C. coli serogroup 20, biotype I (Lior scheme). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that protein and lipopolysaccharide profiles of whole cell preparations of the 10 cephalothin-susceptible strains and the reference strain for C. coli serogroup 20 were very similar. The plasmid profiles of these 11 strains were identical.

Abattoirs↗
PubMed1985

Isolation, characterization, and serotyping of Campylobacter jejuni and Campylobacter coli from slaughter cattle.

A total of 525 specimens from 100 slaughter beef cattle were examined for the presence of Campylobacter jejuni and Campylobacter coli by direct plating and enrichment techniques. Isolates were identified by cultural, biochemical, antibiotic sensitivity, and immunofluorescence tests and further characterized with the aid of recently developed biotyping and serotyping methods. Fifty animals were positive for C. jejuni; only one was positive for C. coli. The distribution pattern of C. jejuni-positive animals, in decreasing order, was steers (55%), bulls (40%), heifers (40%), and cows (22%). Significantly higher isolation rates were obtained from the gall bladders (33%), large intestines (35%), and small intestines (31%) than from the livers (12%) or the lymph nodes (1.4%). C. jejuni isolation by the enrichment technique was 40.2% more frequent than by direct plating; 24-h enrichment resulted in 24% more isolations than 48-h enrichment. Eighty-four of 105 C. jejuni cultures were typable serologically and represented 13 serogroups. Biotype I accounted for 71% of biotyped cultures. Serogroup 7 biotype I was the most commonly encountered (24%) isolate. About one in three positive animals had C. jejuni strains representing more than one serogroup. C. jejuni serogroups encountered in slaughter cattle were similar to those commonly isolated from human sources.

Abattoirs↗
PubMed1984

Quantitative evaluation of a transport-enrichment medium for Campylobacter fetus.

The enrichment feature of a selective serum-based transport medium for Campylobacter fetus was quantitatively examined. Preputial samples from artificial insemination bulls were spiked with known numbers of C fetus strains and inoculated into transport-enrichment medium (TEM). The survival and multiplication of these strains in TEM under different incubation periods and temperatures were assessed by plate counts. Mean enrichment values of 3.72 log and 4.42 log were observed after incubation at 37 degrees C for two and four days, respectively. There was no significant difference in the enrichment values between the C fetus subspecies venerealis strains and a C fetus subspecies fetus strain. Incubation of inoculated TEM vials at room temperature for up to two days neither improved the growth of C fetus nor affected its subsequent enrichment when the vials were reincubated at 37 degrees C. Comparison of the survival of C fetus with and without the use of TEM under simulated transport conditions demonstrated the superiority of TEM.

Animals↗
PubMed1984

An hemolysis-in-gel test for bovine brucellosis.

An hemolysis-in-gel test (HIGT) for bovine antibody against Brucella abortus was developed and evaluated. Sera to be tested were placed in wells in an agarose gel containing guinea pig complement and J-negative bovine erythrocytes coated with lipopolysaccharide prepared from B. abortus biotype 1. After incubation, zones of hemolysis were produced by positive sera. The activity of some positive sera was heat labile, but was restored to heated sera by addition of a crude preparation of the first component of bovine complement. The HIGT was compared with the complement fixation test (CFT), the buffered antigen plate test (BPAT), the standard tube agglutination test (STAT) and the standard plate agglutination test (SPAT), using sera from 1041 brucellosis-free cattle, from 51 cattle infected with B. abortus biotype 1 or biotype 4, and from six heifers vaccinated with strain 19. Three of 1041 sera (0.29%) from brucellosis-free cattle were HIGT-positive, ten (0.96%) were BPAT-positive, and none were positive in the CFT, STAT, or SPAT. The HIGT was more sensitive, and detected infection earlier than the other tests in the case of B. abortus biotype 1 infection, but was less sensitive for biotype 4 infection. In vaccinated heifers, HIGT reactions appeared later than reactions to the other tests, and persisted as long as 565 days. Further studies are needed to standardize the HIGT test conditions and to improve its sensitivity for B. abortus biotype 4 infections. Attempts to determine the effects of LPS antigen prepared from different biotypes of B. abortus are in progress.

Agglutination Tests↗
PubMed1983

Detection of Campylobacter fetus in artificial insemination bulls with a transport enrichment medium.

One hundred and five bulls from an artificial insemination unit were tested for the presence of Campylobacter fetus subspecies venerealis. The method involved the inoculation of preputial samples into a new transport enrichment medium prior to culture and immunofluorescence tests. Seventeen bulls (16%) were found to be either positive or suspected carriers of C. fetus at one or more sampling times. The average age of these 17 bulls was about two years greater than the average age of all the bulls in the unit. A combined treatment of vaccination and dihydrostreptomycin sulfate injection suppressed or eliminated the organism from carrier bulls. The use of transport enrichment medium has increased our capability and effectiveness to monitor the presence of C. fetus in artificial insemination bulls.

Age Factors↗
PubMed1982

Two radioimmunoassays compared with isoenzyme electrophoresis for the detection of serum creatine kinase-MB in acute myocardial infarction.

We have evaluated two commercial radioimmunoassay (RIA) reagent kits for the estimation of the MB isoenzyme of creating kinase (CK). Although both methods use CK-B antisera and radioiodinated CK-B, one ("M" for Mallinckrodt) uses hybridized CK-MB for calibration, while the other ("NMS" for Nuclear Medical Systems) uses CK-B. Both assays provide adequate sensitivity, precision, and specificity for the estimation of serum CK-MB. Ninety-nine patients admitted consecutively to our coronary care unit were studied. Apparent CK-MB was measured by both RIAs and results compared with CK-MB enzymatic activity after electrophoresis (E). CK-MB was elevated, as judged by E and by M, in all of 42 patients with acute myocardial infarction (AMI), and in 40 of the 42 by NMS. Of the 57 patients who did not have an AMI, eight had elevated CK-MB by E, 16 by M, and 25 by NMS. Patients with persistently elevated apparent CK-MB concentrations not associated with AMI were identified by M and by NMS, but not by E. The ability to differentiate AMI from no infarction in patients was best with E, and was not satisfactory by NMS. Although the detection of AMI by M equaled that by E, the large number of apparent false-positive results hindered the clinical application of RIA CK-MB measurements.

Acute Disease↗
PubMed1981

The triiodothyronine uptake test: an assessment of methods.

How well the free thyroxine index reflects thyroid functional status depends on the degree to which the triiodothyronine uptake test normalizes the effects of thyroxine binding protein concentrations on the total thyroxine concentration. We examined eight triiodothyronine uptake tests in which were used different secondary binders representative of those available in commercial kits. The relation between triiodothyronine uptake and thyroxine-binding globulin concentrations was established by use of sera from euthyroid individuals. We examined the effects of both high (greater than 20 mg/L) and low (less than 10 mg/L) thyroxine-binding globulin concentrations on triiodothyronine uptake. The precision of each assay, expressed as within- and between-run coefficient of variation, was calculated from multiple measurements on high, low, and midrange triiodothyronine uptake serum pools. The effects of variation in temperature and in exposure times were examined. The clinical most useful assays exhibited the ability to reflect a wide range of thyroxine-binding globulin concentrations and demonstrated little or no time or temperature effects.

Humans↗