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Biomedical subjects

J Gomez

Publications and source records attributed to J Gomez.

At least 19 recordsLinked to original sources
PubMed1992

Pathological lesions following an experimental intoxication with aflatoxin B1 in broiler chickens.

A follow-up of chickens dosed orally over 21 days with 0.2 and 3 micrograms of aflatoxin B1 (AFB1) g-1 of bodyweight daily and their subsequent recovery 10 days after withdrawal of contaminated food was conducted. Vacuolation of liver cells during the initial days of the intoxication and cellular depletion in the follicle medulla of the bursa of Fabricius were the lesions which appeared first and persisted during the recovery phase in both groups of intoxicated animals. The intensity of these lesions and their persistence was related to the dose of aflatoxin ingested. A significant reduction in the bodyweight and absolute weights of liver, bursa of Fabricius spleen and thyroid was observed in the higher dose group.

Aflatoxin B1↗
PubMed1992

Modification of the methodology of stool culture for Salmonella detection.

A total of 4,284 H2S-positive colonies isolated on salmonella-shigella agar and 4,350 isolated on Hektoen agar were flooded with 5 microliters of a reagent (MUCAP test; Biolife Italiana S.r.l., Milan, Italy) and observed after 3 to 5 min for the development of fluorescence produced in the presence of the C8 esterase enzyme. All of the 794 colonies isolated on salmonella-shigella agar and the 752 isolated on Hektoen agar and identified as positive for Salmonella spp. with conventional biochemical tests were found positive with the MUCAP test (the sensitivity was 100% and the negative predictive value was 100% for both media). Moreover, only six isolates identified by conventional biochemical tests as Proteus vulgaris were MUCAP test positive (the specificity was 99.8% and the positive predictive value was 99.2% for both media). On the basis of these results, we propose the use of the MUCAP test as a method for the screening of H2S-positive colonies and only subculturing on Kliger agar of those colonies which are MUCAP test positive. The MUCAP test is a rapid method for the presumptive detection of Salmonella spp. and reduces the work and material involved in testing.

Bacteriological Techniques↗
PubMed1992

Grouping of hantaviruses by small (S) genome segment polymerase chain reaction and amplification of viral RNA from wild-caught rats.

A single pair of consensus primers in the polymerase chain reaction (PCR) amplified a conserved region of the small genome segment of twenty hantavirus isolates. Isolates tested included representatives of the four recognized hantaviruses, Hantaan, Seoul, Puumala and Prospect Hill, as well as isolates from Mus musculus (Leakey), Bandicota indica (Thailand 749), and Suncus murinus (Thottapalayam). Viruses from the Nairovirus and Phlebovirus genera yielded negative results. The amplification products were 281-nucleotide pairs (np) in length, with the exception of Thottapalayam, which had an amplification product of approximately 320 np. Products of all isolates were detected by Southern hybridization with a 32P-labeled Hantaan 76-118 amplicon, while an oligonucleotide probe to a conserved region of the amplified fragment failed to detect some isolates of Seoul and Puumala viruses. Restriction endonuclease analysis allowed three groupings: Hantaan-like viruses, Seoul-like viruses, and a diverse group of patterns for the other viruses. Differences were found within the Seoul-like virus group by this method, whereas the Hantaan-like viruses were shown to be similar. RNA extracted from tissues of seropositive and seronegative rats trapped in Baltimore showed the practical application of the test. Hantavirus-specific RNA was detected in 12 (92%) of 13 seropositive rats, but not in seronegative rats. This simple method for detecting and characterizing hantaviruses has potential for epidemiologic studies and for diagnosing human hantavirus infections.

Animals↗
PubMed1992

[Comparison of methods for determining corn hardness (Zea mays L.)].

One of the most important intrinsic properties of corn kernels is hardness. Nowadays controversy exists as to which method is more accurate to measure this property. In the present study, therefore, several methods for measuring hardness in corn kernels are compared, for the purpose of finding the most appropriate one. A corn population ranking from hard to soft was tested. The methods tested were: endosperm texture (ET), pearling index (PI) floating index (FI), density (D), near infrared reflectance (NIR), test weight (Ph) and time required to grind the corn with the Brabender automatic micro-hardness (TDB) method. The floating index (FI) method was found to be the most suitable one for determining hardness of corn kernels. This method permitted determination of the differences existing in corn with hard, intermediate, and soft-textured endosperms, with low variation coefficients. The TDB and NIR methods were not appropriate to determine the hardness of corn kernels, showing high variability in the results. With the Ph and D methods it was difficult to distinguish between corn with hard, intermediate and soft texture endosperm.

Evaluation Studies as Topic↗
PubMed1992

Photodynamic effects of a cationic mesosubstituted porphyrin in cell cultures.

The photobiological activity of mesotetra (4N-methylpyridyl) porphine (T4MPyP) has been studied in a mammalian cell line in vitro. The uptake of T4MPyP to HeLa cells was examined using fluorescence microscopy. Under violet-blue exciting light, a nucleus-selective red fluorescence was detected. The intensity of fluorescence depended on drug concentration and incubation time, with a maximum relative emission at a concentration value of 10(-5) M for 20 min. The photosensitivity of HeLa cells incubated with T4MPyP under previous conditions and subsequently exposed to variable doses of visible light has been examined. Cell toxicity was evaluated as the surviving fraction, using the trypan blue staining test. The extent of cellular damage was found to be dependent on irradiation time, with a lethal damage after 8 min of light exposure. Cellular DNA-photodamage was studied under sublethal conditions (2 min of irradiation) by the use of the micronucleus test. The number of micronuclei, in these conditions, increased with regard to baseline levels.

Cell Nucleus↗
PubMed1991

Presumptive identification of Salmonella enterica using two rapid tests.

Two rapid test for early detection of Salmonella enterica, the cytochrome oxidase test and a fluorescence test, were evaluated in 1,200 colonies which had been isolated from human feces and cultured on MacConkey and Salmonella-Shigella media. Using the fluorescence test there were no false negative results (sensitivity 100%) and of 205 positive cases 62 did not correspond biochemically to salmonella (specificity 94.1%); 44 of these 62 were positive in the cytochrome oxidase test, raising the specificity to 98.2%. In conclusion, the combination of the two tests could be very useful due to the ease of performance, low cost and excellent results obtained.

Culture Media↗
PubMed1990

Combination therapy with flutamide and medical (LHRH agonist) or surgical castration in advanced prostate cancer: 7-year clinical experience.

Three hundred and sixty-three patients with clinical stage D2 prostate cancer who had not received previous endocrine therapy or chemotherapy were treated with the combination therapy using the pure antiandrogen Flutamide and the LHRH agonist [D-Trp6,des-Gly-NH2(10)]LHRH ethylamide (or orchiectomy) for an average of 771 days (24-2607 days). Only 31 of the 308 evaluable patients (10.1%) did not show an objective positive response at the start of the combination therapy compared with an average of 18% in five recent studies using monotherapy. The median survival achieved using monotherapy is approximately 24 months while, in the present study, it is increased to 41.2 months, thus giving an additional 17 months of survival with the combination therapy. It should be mentioned that at the time of relapse, combination therapy is continued and, in addition, further blockade of adrenal androgen secretion is achieved with aminoglutethimide and hydrocortisone. While our studies showing the advantages of combination therapy with pure antiandrogen in advanced prostate cancer have been confirmed by independent large-scale randomized studies, our preliminary data clearly suggest the interest of downstaging early stage prostate cancer by temporary combination therapy prior to radical prostatectomy.

Adenocarcinoma↗
PubMed1990

Analysis of the autoagglutination phenomenon, serogroup and hydrophobicity as virulence markers in mesophilic aeromonads isolated from stool cultures.

The autoagglutination phenomenon (AA) was studied in 71 strains of mesophilic aeromonads isolated from stool cultures of patients with acute diarrhea (28 Aeromonas hydrophila, 20 Aeromonas sobria, and 23 Aeromonas caviae). Two phenotypes were considered in the AA+ strains: SP+ (self-pelleting) and PAB+ (precipitation after boiling). Serogrouping of the strains was performed only with the 0:11 serum. Other properties studied were agglutination with acriflavine (Acr) and crystal violet uptake (CVB). Phenotype AA+ was found in 29.5% of the strains; 7% of these AA+ strains exhibited the SP+ PAB+ pattern and 22.5% the SP- PAB+ pattern. The species Aeromonas hydrophila comprised the highest proportion (28.5%), and Aeromonas caviae the lowest (13%). Fifty percent of the PAB+ strains of Aeromonas hydrophila and Aeromonas sobria belonged to serotype 0:11. None of the PAB+ strains of Aeromonas caviae belonged to this serotype. 8.4% of the strains were Acr+ and 23.9% CVB+.

Acute Disease↗
PubMed1990

Microbiological characteristics of Weeksella virosa (formerly CDC group IIf) isolated from the human genitourinary tract.

Weeksella virosa (formerly CDC group IIf) is a nonsaccharolytic, oxidase- and catalase-positive, gram-negative rod which is unable to grow on MacConkey agar. At 48 h of incubation on blood or chocolate agar, the colonies present a characteristic appearance: intensely mucoid, adherent, and cream colored as a result of the production of a nondiffusible yellow pigment. This microorganism has been isolated predominantly from the female genitourinary tract, which indicates the opportunity for sexual transmission. We present the microbiological study of three strains of W. virosa identified in a study of 707 female genital samples, representing an incidence of 0.42%. At the same time, we analyzed the principal biochemical tests used in the identification of this microorganism and the susceptibilities of the organism to the different antimicrobial agents assayed.

Female↗
PubMed1990

Characterization of receptors for platelet-activating factor in guinea pig lung membranes.

Platelet-activating factor (PAF) is a potent contractile agonist in guinea pig peripheral lung strips. Whether PAF acts via specific receptor sites in the lung has not been fully established. To determine if specific receptor sites could be demonstrated in guinea pig peripheral lung tissue, we performed direct radioligand binding studies in tissue homogenates with [3H]C16-PAF (1-O-hexadecyl-sn-glyceryl-3-phosphorylcholine) and the PAF antagonists [3H]WEB 2086 and [3H]RP52770. These studies demonstrated binding sites for [3H]C16-PAF of high affinity (Kd of 2.6 nM from saturation isotherms and 0.9 nM from kinetic experiments) and a mean density of 200 fmol/mg protein. Binding was inhibited to the same degree with unlabeled C16-PAF, WEB 2086, and RP52770, all with pseudo-Hill slopes of unity. [3H]WEB 2086 binding demonstrated a receptor density similar to that of [3H]C16-PAF (226 fmol/mg protein) and was inhibited to the same degree by unlabeled C16-PAF, C18-PAF, WEB 2086, and RP52770. Although antagonist inhibition yielded pseudo-Hill slopes near unity, agonist inhibition slopes were shallow, suggesting two types or states for the PAF receptors. Direct binding studies with [3H]RP52770 revealed a much larger density of binding sites (1,200 fmol/mg protein), and this binding was not inhibited with C16-PAF, C18-PAF, WEB 2086, or lyso-PAF. These results indicate that guinea pig lung has specific binding sites for [3H]C16-PAF, that WEB 2086 is an effective antagonist of C16- and C18-PAF binding at these sites, and that RP52770 binds to the PAF site but, in addition, binds to another site with a much greater density.

Animals↗
PubMed1989

Subjective response during continuous infusion of cocaine.

The relationship between the subjective effects induced by IV cocaine injection(s) and cocaine plasma concentrations is complex and difficult to interpret. We designed a study in which bolus loading doses of cocaine followed by 4-hr placebo infusions were compared with the same bolus loading doses of cocaine followed by 4-hr infusions of cocaine calculated to maintain the peak plasma concentrations produced by the bolus. Seven cocaine-using volunteers were successfully studied using a randomized double-blind design, in which self- and observer-rating scales were used to measure drug effects. After the cocaine bolus loading doses, scores for most subjective measures remained elevated when the bolus was followed by a cocaine infusion. In contrast, the subjective responses returned to baseline when the bolus was followed by a placebo infusion. However, self-estimates of the intensity of the cocaine "rush" were not altered by the presence of active cocaine infusions and returned rapidly to baseline.

Adult↗
PubMed1989

Disruption of auditory function by acute administration of a "room odorizer" containing butyl nitrite in rats.

Butyl nitrite is the predominant and presumed active ingredient in a variety of commercial preparations sold as "room odorizers." These compounds have significant abuse potential, giving the user the sensation of a "rush", which may be related to their intense cardiovascular effects. The pharmacological properties of butyl nitrites are similar to those of amyl nitrite which is also abused for its psychological effects, but whose availability is limited by prescription for treatment of angina. A significant body of literature suggests that the inner ear is vulnerable to acute hypoxic exposure. Since butyl nitrite induces high levels of methemoglobin and also reduces blood pressure due to peripheral vasodilation, we hypothesized that this compound might produce auditory dysfunction. We studied the effect of acute exposure to a butyl nitrite "room odorizer" on 10- and 40-kHz auditory function in rats. A loss in auditory sensitivity was found at both frequencies on the day following administration of the compound. Auditory dysfunction tended to subside over the next several days at 40 kHz, although a significant loss of sensitivity for tones of 10 kHz was observed over a 6-day period after administration of the agent. Methemoglobin levels measured in rats of the same age were elevated significantly 30 and 60 min after butyl nitrite to levels of 30-45%. Methemoglobin levels were found to be normal 18 hr after administration when the first audiometric tests were conducted. The data suggest that auditory function in the middle of the rats' auditory range, 10 kHz, was disrupted for a longer period than was high-frequency (40 kHz) auditory function.

Air Pollutants↗
PubMed1989

Value of sonography in true complete diphallia.

A case of true complete diphallia associated with multiple malformations is presented. Complete radiological evaluation should include sonography of both penes preoperatively to classify the penile duplication correctly.

Abnormalities, Multiple↗
PubMed1989

Use of ceftriaxone in the treatment of bacterial infections in cirrhotic patients.

Sixty-two episodes of bacterial infection were studied in 51 cirrhotic patients. 2 g of ceftriaxone (active ingredient of Rocephin) were given intravenously once daily for 7-10 days. The infections were pneumonia, bacteremia, spontaneous bacterial peritonitis, urinary infection and others. Good responses were seen in 90% of the cases.

Adult↗
PubMed1989

Analysis of the individual allergens of Russian thistle pollen by an enzyme-linked immunoblotting technique.

Russian thistle pollen extract was analyzed by immunoblots of isoelectric focused and SDS-PAGE gels. Twenty distinct protein bands were recognized by human IgE- and IgG-specific antibodies in the immunoblot from the SDS-PAGE gel. Molecular weights of these allergens ranged from 12.2 kD to 85 kD. Seventeen bands were detected on isoelectric focusing immunoblots with pI from 3.95 to 7.70. Allergic subjects had differing individual patterns of protein band recognition. Immunoblot techniques provide detailed evaluations of the response of allergy subjects to components of crude natural allergens.

Allergens↗