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Biomedical subjects

J Martinez

Publications and source records attributed to J Martinez.

At least 253 records · Page 14Linked to original sources

Assessment of sensitization to holm oak (Quercus ilex) pollen in the Mérida area (Spain).

Sensitization to Quercus ilex (holm oak) was studied in 760 patients with clinically suspected sensitization to aeroallergens. Prick tests with commercial extracts of Q. ilex proved positive in 27 patients; none were monosensitive. Nasal and conjunctival provocation tests and specific IgE (RAST) performed with Q. ilex extracts in these patients were negative in all but one patient, who exhibited specific IgE titer (by RAST) of 7 PRU/ml (class 3). We conclude that Q. ilex pollen, though obtained in considerable quantities by our collector, does not cause allergies in our area.

Adolescent↗

Derived structure of the putative sialic acid transporter from Escherichia coli predicts a novel sugar permease domain.

Catabolism of sialic acids by Escherichia coli requires the genes nanA and nanT, which were previously mapped between argG and rpoN (E.R. Vimr and F.A. Troy, J. Bacteriol. 164:845-853, 1985). This organization is confirmed and extended by physical mapping techniques. An open reading frame beginning 135 bp from the nanA translational stop codon could code for a 53,547-Da hydrophobic polypeptide predicted to contain 14 transmembrane segments. Complementation analysis confirmed that nanT is required for sialic acid uptake when expressed in trans. NanT is homologous to a putative permease encoded by open reading frame 425, which maps between leuX and fecE in the E. coli chromosome. However, unlike this hypothetical permease or previously reported monosaccharide transporters, NanT contains a centrally located domain with two additional potential membrane-spanning segments plus one amphiphilic alpha-helix that may be important for the structure and function of sialic acid-permease.

Amino Acid Sequence↗

Interference by hydroxyethyl starch used for vascular filling in latex agglutination test for cryptococcal antigen.

The glucuronoxylomannan component of the Cryptococcus neoformans capsular polysaccharide confers serotype specificity, and its detection in cerebrospinal fluid or serum by the latex agglutination test is used for diagnosis. Low-molecular-weight hydroxyethyl starches can be used as an alternative to albumin for vascular filling. This study reports the occurrence of a false-positive result with the Pastorex Cryptococcus test (Sanofi Diagnostics Pasteur, Marnes la Coquette, France) for a patient receiving hydroxyethyl starch characterized by a substitution ratio of 0.6 (Elohes, Biosedra, Sèvres, France).

Antigens, Fungal↗

Sorbitol-negative phenotype among enterohemorrhagic Escherichia coli strains of different serotypes and from different sources.

Enterohemorrhagic Escherichia coli (EHEC) strains detected with DNA probes (for virulence plasmid and Shiga-like toxins) from subjects with hemolytic-uremic syndrome (n = 19) or diarrhea (n = 41) or asymptomatic carriers (n = 29) were examined for sorbitol fermentability, as were enterotoxigenic (n = 40), enteropathogenic (n = 40), and enteroinvasive (n = 40) E. coli and urinary tract infection (n = 40) strains and normal flora E. coli strains (n = 40). Sorbitol negativity was common only in EHEC, particularly among strains from severe clinical infections. All 19 EHEC strains from patients with hemolytic-uremic syndrome, irrespective of O:H serotype or Shiga-like toxin genotype, were sorbitol negative.

Carrier State↗

Characterisation of the influence of anti-gastrin, anti-epidermal growth factor, anti-oestradiol, and anti-luteinising hormone releasing hormone antibodies on the proliferation of 27 cell lines from the gastrointestinal tract.

Numerous data from published reports prove that the proliferation of gastrointestinal tumour cell lines are under the control of many hormones or growth factors, or both. Most of these publications report the influence on a very small number of cell lines of one or two such factors only. This work deals with the in vitro characterisation of the influence of the anti-gastrin, the anti-epidermal growth factor (EGF), the anti-oestradiol (E2), and the anti-luteinising hormone releasing hormone (LHRH) antibodies on the proliferation of a large series of gastrointestinal cell lines. Cell proliferation was assessed by means of the colorimetric MTT assay on a series of 27 gastrointestinal cell lines obtained from the American Type Culture Collection (ATCC). Of the 27 cell lines, the anti-gastrin, the anti-EGF, the anti-E2, and the anti-LHRH neutralising antibodies considerably influenced the proliferation of 13, 25, 12, and 16. No gastrointestinal cell line was unresponsive to the four antibodies simultaneously. The anti-gastrin and anti-EGF antibody induced effects on the 27 gastrointestinal cell line proliferation were significantly correlated, as was also the case for the anti-E2 and anti-LHRH antibody induced effects. Of the anti-gastrin, the anti-EGF, the anti-E2, and the anti-LHRH antibodies, it was the anti-EGF one that had the greatest influence, both quantitatively and qualitatively, on gastrointestinal cell proliferation. The correlation of the effects of definite anti-hormone antibodies is suggestive of a common mechanism of action for the corresponding hormones and casts some doubt on the efficiency of anti-hormone monotherapy.

Animals↗

Early pulmonary inflammation in infants with cystic fibrosis.

The mechanisms underlying the initiation of lung disease and early respiratory morbidity in cystic fibrosis (CF) are poorly understood. By identifying infants with CF through a statewide neonatal screening program, we investigated whether airway inflammation was present in these infants, with the goal of furthering our understanding of the early events in this lung disease. Bronchoalveolar lavage fluid (BALF) from 16 infants with CF (mean age, 6 mo) and 11 disease control infants (mean age, 12 mo) was examined for the following inflammatory parameters: (1) neutrophil count; (2) activity of free neutrophil elastase; (3) elastase/alpha 1-antiprotease inhibitor complexes; and (4) the level of interleukin-8 (IL-8). We also quantified the spontaneous level of expression of IL-8 mRNA transcripts by airway macrophages. Each index of airway inflammation was increased in the BALF of infants with CF as compared with control infants. In addition, both the number of neutrophils and IL-8 levels were increased in infants with CF who had negative cultures (n = 7) for common bacterial CF-related pathogens, as well as for common respiratory viruses and fungi at the time of bronchoalveolar lavage (BAL). These findings suggest that airway inflammation is already present in infants with CF who are as young as 4 wks. Furthermore, although many different cell types (e.g., epithelial cells) may express IL-8, airway macrophages appear to be a source of this chemokine, and may thus play a prominent role in early neutrophil influx into the lung.

Base Sequence↗

Persistence of blunted human growth hormone response to clonidine in fluoxetine-treated patients with panic disorder.

OBJECTIVE: The authors determined the effects of antipanic treatment with fluoxetine on human growth hormone (GH) response to the alpha 2 agonist clonidine. METHOD: Seventeen patients with panic disorder and 15 healthy volunteers were challenged with clonidine. Thirteen of the patients and 12 of the volunteers were given a second challenge with clonidine 12 weeks later. The patients received open fluoxetine and the healthy subjects received no treatment between challenges. Subjects with high baseline human GH levels (greater than 2 ng/ml) at the first and second challenges were excluded from further analysis. RESULTS: The patients with panic disorder (N = 13 for the first challenge and N = 9 for the second) had significantly lower human GH responses to clonidine than the healthy subjects (N = 14 during the first challenge and N = 9 for the second) during both challenges, despite clinical improvement in eight of the nine patients at the time of the second challenge. CONCLUSIONS: Blunted secretion of human GH in response to clonidine in patients with panic disorder persists despite clinical recovery.

Clonidine↗

AIDS and palliative medicine: medical treatment issues.

Caring for patients with AIDS in hospice programs presents numerous challenges. These go beyond the strictly medical decisions discussed in this article to include unique problems with social support, emotional support, and bereavement. This discussion centers on medical issues as they are commonly encountered. They can be stumbling blocks, or even surrogates, for addressing the other important issues at the end of life. Communication between all people involved in the multidisciplinary treatment of these patients is essential. Common goals should be identified and general approaches agreed upon among the physicians, nurses (clinic, hospice, home care), therapists, clergy, and volunteers. In this way we feel that the principles of hospice and palliative care can be effectively applied to most patients with endstage AIDS.

AIDS-Related Opportunistic Infections↗

Characterization of latex and chestnut antigens by immunoblotting.

BACKGROUND: Cross-reactions between latex, chestnut, and other fruits have been demonstrated by RAST, although the results show some discrepancies. OBJECTIVE: To detect and characterize cross-reacting antigens in both extracts by immunoblotting. METHODS: Polyclonal rabbit antisera were raised against ammoniated latex and an aqueous chestnut extract. The antigenic extracts were studied by immunoblotting using a diffusion transfer method. Cross-reactivities were measured by immunoblotting inhibition. RESULTS: Both antisera detected a high number of antigenic proteins in both latex and chestnut extracts. Latex was a good self-inhibitor and inhibitor of chestnut with respect to both antisera. Chestnut was only a good inhibitor for the two antisera on the chestnut-blot as well as on the latex-blot when the anti-chestnut antiserum was employed. No inhibition was obtained on latex immunoblotting by chestnut using anti-latex antiserum. CONCLUSIONS: The results suggested that latex and chestnut contained common epitopes detected by antibodies raised by immunization with both antigens. The anti-latex antiserum, however, possessed antibodies that could not be inhibited by other allergens. This could explain why latex has been described as a good inhibitor of chestnut-RAST while no inhibition by chestnut was found on the latex-RAST in latex and chestnut allergic patients. Other common pollen extracts were also inhibitors of immunoblotting with the exception of the latex/anti-latex pair. This suggests that antibodies induced by immunization with latex or chestnut showed unexpected cross-reactions.

Animals↗

alpha-Conotoxin ImI exhibits subtype-specific nicotinic acetylcholine receptor blockade: preferential inhibition of homomeric alpha 7 and alpha 9 receptors.

Through a study of cloned nicotinic receptors expressed in Xenopus oocytes, we provide evidence that alpha-conotoxin ImI, a peptide marine snail toxin that induces seizures in rodents, selectively blocks subtypes of nicotinic acetylcholine receptors. alpha-Conotoxin ImI blocks homomeric alpha 7 nicotinic receptors with the highest apparent affinity and homomeric alpha 9 receptors with 8-fold lower affinity. This toxin has no effect on receptors composed of alpha 2 beta 2, alpha 3 beta 2, alpha 4 beta 2, alpha 2 beta 4, alpha 3 beta 4, or alpha 4 beta 4 subunit combinations. In contrast to alpha-bungarotoxin, which has high affinity for alpha 7, alpha 9, and alpha 1 beta 1 gamma delta receptors, alpha-conotoxin ImI has low affinity for the muscle nAChR. Related Conus peptides, alpha-conotoxins MI and GI, exhibit a distinct specificity, strictly targeting the muscle subtype receptor but not alpha 7 or alpha 9 receptors. alpha-Conotoxins thus represent selective tools for the study of neuronal nicotinic acetylcholine receptors.

Amino Acid Sequence↗

Surgical clips as a nidus for biliary stone formation: diagnosis and therapy.

Two cases in which a cystic duct stump clip migrated into the common bile duct and formed the nidus for a stone are reported. In one case, the diagnosis was made before ERCP, on the basis of CT findings. In the second case, a retrospective review of plain abdominal films showed evidence of clip migration. Both patients were treated successfully with endoscopic sphincterotomy, as have most such patients reported in the literature. Although clip migration can occur after both open and laparoscopic cholecystectomy, there is some evidence that this complication may be more common after the laparoscopic procedure. Clip migration can be diagnosed before cholangiography by carefully reviewing plain abdominal films and CT scans. ERCP confirms the diagnosis, and sphincterotomy with clip and stone removal is the therapeutic procedure of choice. Additional surgical procedures only rarely are required.

Aged↗

Analysis of the cysteine proteinases of Leishmania mexicana and Trypanosoma cruzi using specific antisera.

Antisera raised against papain and cysteine proteinases (CPs) purified from Leishmania mexicana and Trypanosoma cruzi have been used to study the proteins in the two parasites. The antisera against the major CP of T. cruzi (cruzipain) not only cross-reacted with known CPs of L. mexicana but also detected stage-specific molecules that may represent previously unrecognised CPs. The binding of the same antisera to extracts of different life cycle stages of T. cruzi suggested that the stages possess different isoforms of cruzipain. The lack of cross-reactivity of anti-papain antiserum against cruzipain suggests that the major immunogenic epitopes of these CPs are different, whereas the detection of the major CPs of L. mexicana with both heterologous antisera shows that the parasite's enzymes share epitopes with the other CPs.

Animals↗

Subcutaneous formalin produces centrifugal hyperalgesia at a non-injected site via the NMDA-nitric oxide cascade.

Previous work has demonstrated that pain facilitation can occur following injection of subcutaneous irritants, such as formalin. Such studies have focused on apparent pain facilitation induced at the site of irritant injection. Changes in processing of incoming pain information have typically been assumed to result from activation of neurocircuitry intrinsic to the spinal cord. The present series of studies have examined hyperalgesia exhibited at a site distant from the site of irritant injection and have begun to define the neurocircuitry and neuropharmacology underlying this pain enhancement. This work demonstrates that s.c. formalin injected into the dorsum of one hindpaw in rats produces prolonged hyperalgesia as measured by the tailflick test. Hyperalgesia is not mediated solely by circuitry intrinsic to the spinal cord, but rather involves activation of centrifugal pathways originating within the brain and descending to the spinal cord via pathway(s) outside of the dorsolateral funiculus. At the level of the spinal cord, this hyperalgesic state is mediated by an NMDA-nitric oxide cascade, since hyperalgesia can be abolished by administration of either an NMDA antagonist (APV) or a nitric oxide synthesis inhibitor (L-NAME).

2-Amino-5-phosphonovalerate↗

Differentiating macular holes from macular pseudoholes.

Surgical treatments of macular holes have become increasingly effective in inducing resolution of the cuff of surrounding subretinal fluid, resulting in increased vision in many patients. However, for many conditions that mimic a macular hole, either surgery is not indicated or different surgical manipulations are necessary. Differentiating macular holes from some forms of macular pseudoholes can be difficult or impossible based solely on clinical examination. Adjunctive tests that may enhance the accuracy of diagnosis are either not feasible or not available to most clinical practices. We evaluated three clinic-based tests for their value in allowing the differentiation between macular holes and macular pseudoholes: Amsler grid testing, Watzke-Allen sign, and laser aiming beam test. These tests were evaluated in three groups of clinically defined patients: those with full-thickness macular holes, those with macular pseudoholes, and those who had previously undergone successful macular hole treatment. Although the Amsler grid testing was sensitive in correlating with clinically defined macular holes, it was not specific. The Watzke-Allen sign and, to a greater extent, the laser aiming beam test were extremely sensitive and specific in correlating clinically defined full-thickness macular holes and pseudoholes. These tests improve the accuracy of diagnosis of full-thickness macular holes.

Aged↗

Gastrin13 and the C-terminal octapeptide of cholecystokinin are differently coupled to G-proteins in guinea-pig brain membranes.

In the course of our study concerning gastrin and cholecystokinin (CCK) receptors, we synthesized and characterized a labelled gastrin ligand, [125I]BH[Leu15]gastrin-(5-17) (3-(3-[125I]iodo-4-hydroxyphenyl)propionyl[Leu15]gastrin-(5-17)). On isolated canine fundic mucosal cells and human Jurkat lymphoblastic cell line, known to express CCKB/gastrin receptors, the binding experiments performed indicate that [125I]BH[Leu15]gastrin-(5-17) provides a convenient biologically active ligand for cholecystokinin/gastrin receptor studies. We showed in this study that, on guinea-pig brain membranes known to possess CCKB and CCKA receptors, [125I]BH[Leu15]gastrin-(5-17) binds to a single class of high-affinity binding sites in a saturable and specific manner. [125I]BH[Leu15]gastrin-(5-17) interacts with guinea-pig brain membranes with a maximal binding capacity that is about three-fold lower than that of [125I]BHCCK8 (CCK8, the C-terminal octapeptide of cholecystokinin). The apparent affinities of CCK analogues and selective CCK receptor antagonists L-365,260 and MK-329 for the sites labelled by both probes were in accordance with a CCKB-like profile. Association-dissociation kinetics of [125I]BH[Leu15]gastrin-(5-17) and [125I]BHCCK8 were performed and compared. They showed that [125I]BHCCK8 equilibrated more slowly than [125I]BH[Leu15]gastrin-(5-17). The effects of pH, monovalent and divalent cations on binding of both probes were investigated. The results obtained did not indicate strong differences between [125I]BH[Leu15]gastrin-(5-17) and [125I]BHCCK8 binding. Binding experiments in the presence of stable analogues of GTP showed a different behavior between [125I]BH[Leu15]gastrin-(5-17) and [125I]BHCCK8. GTP gamma S strongly decreased [125I]BH[Leu15]gastrin-(5-17) binding whereas it weakly affected [125I]BHCCK8 binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗