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Biomedical subjects

A Lee

Publications and source records attributed to A Lee.

At least 379 records · Page 21Linked to original sources
PubMed1997

Monoclonal antibodies as direct probes for human sperm acrosome reaction.

PROBLEM: To develop simple and rapid assay procedures for determining human sperm acrosome reaction under various experimental conditions. METHODS: Specific monoclonal antibodies against human sperm acrosome were generated and utilized as probes for acrosome reaction assays by direct labelling of antibodies with fluorescein-isothiocyanate (FITC). RESULTS: Among the generated monoclonal antibodies, HS-63 was shown to react with antigens in the acrosome content of permeabilized acrosome-intact human sperm, but not with those of the live ones. HSA-10 was found to recognize antigens on the surface of sperm inner acrosome and to react with acrosome-reacted human sperm in suspension. Following a swim-up procedure, highly motile sperm were recovered and incubated in BWW medium at 37 degrees C for 18 h. The percentages of acrosome-reacted sperm were determined at various incubation times by using FITC-labeled HS-63 or HSA-10 as the indicators in 10 min direct immunofluorescent assay. With the FITC-labeled HS-63 probe, the percentage of positively stained human sperm fixed in methanol decreased significantly after 18 h of incubation from > 90 to 70-80%. In contrast, positively stained live human sperm by HSA-10 increased significantly from < 1% to 15-30%. A high correlation was obtained between the use of monoclonal antibodies and PSA (Pissum sativum agglutinin) for direct assessment of human sperm acrosome reaction. CONCLUSION: In view of the simplicity in assay procedures and evaluations, these FITC-labeled monoclonal antibodies are reliable probes for direct assessment of acrosomal status of human sperm.

Acrosome↗
PubMed1997

Catalase, a novel antigen for Helicobacter pylori vaccination.

The efficacy of an orogastric vaccine comprised of purified Helicobacter pylori catalase plus the mucosal adjuvant cholera toxin (CT) was examined with both the Helicobacter felis and H. pylori mouse models with BALB/c mice. Native H. pylori catalase (200 microg) plus CT was initially used as a vaccine antigen in the H. felis mouse model and protected 80% (8 of 10) of the challenged animals, while all control animals were infected (20 of 20). In a follow-up experiment, recombinant H. pylori catalase plus CT was used for immunization, and groups of mice were challenged with the Sydney strain of H. pylori. Immunization with recombinant catalase protected a significant proportion (9 of 10) of the mice from H. pylori challenge, indicating that this enzyme should be considered as a candidate for a future vaccine. This study provides the first available data on the efficacy of protective immunization with the new Sydney strain of H. pylori in a mouse model. These data also provide indirect evidence that proteins which are normally intracellular, such as catalase, may be present on the surface of H. pylori and thus may provide targets for immunization.

Animals↗
PubMed1997

The endotoxin of Helicobacter pylori is a modulator of host-dependent gastritis.

Atrophic gastritis caused by Helicobacter pylori is the precursor lesion in the development of intestinal-type gastric adenocarcinoma. In animal models, atrophic gastritis induced by Helicobacter felis has been shown to be host dependent, developing in some mouse strains and not in others. The lipopolysaccharide (LPS) of H. pylori has been suggested to play a role in the induction of gastritis. The goal of this study was to compare the inflammation induced by long-term infection of the C3H/He and the C3H/HeJ strains of mice with H. felis. C3H/HeJ mice are unresponsive to LPS. Six months after infection, severe atrophic gastritis had developed in the body mucosae of all infected C3H/He mice, with replacement of parietal and chief cells. Atrophy was associated with a loss of the H. felis from the antral mucosa. In contrast, no atrophy was seen in the infected C3H/HeJ non-LPS responder animals, and heavy colonization of the antrum remained. There were no significant differences between both the quantitative and qualitative serum immunoglobulin G (IgG) and salivary IgA levels in both strains of mice. The main difference between the two strains of long-term-infected mice was a lack of macrophage infiltration in the lamina propria. Immunization induced good protective immunity to challenge with viable H. felis. Helicobacter-induced, host-dependent gastritis is likely to be cell mediated. The C3H/He and C3H/HeJ mouse model provides an excellent opportunity to investigate the cellular basis of atrophic gastritis.

Animals↗
PubMed1997

Opioid requirements and responses in Asians.

The provision of good analgesia can be influenced by ethnic differences in how pain is expressed, the attitudes of patients and health professionals towards pain management and pharmacological differences in the responses to opioids. It is difficult to generalize results so that they are applicable to any ethnic group as a whole. There is also the question of how best to categorize ethnic Asians who have been in Australasia for several generations. Much of the pharmacogenetic work has focused on the metabolism of codeine, morphine and pethidine, and there are some differences between Chinese and Caucasians. Asians may receive less analgesia because they are more likely to experience, or are less tolerant of the adverse effects of opioids. Despite this, ethnic factors are probably only a small contributor to the inter-individual variation in opioid requirements. Unlike earlier studies, recent larger studies using patient-controlled analgesia have shown similar opioid usage between Asians and Caucasians in the postoperative period. An individualized pain management program is essential for any patient, whatever his or her ethnic origin. The use of patient-controlled analgesia will minimize some of the problems that may occur because of poor communication between the patient and the healthcare staff. Nevertheless, in a multicultural society like Australia's, health professionals should be conscious of the many factors that may influence the effects of prescribed treatment to manage pain in different ethnic groups.

Analgesia↗
PubMed1997

A symptom-based measure of the severity of chronic lung disease: results from the Veterans Health Study.

STUDY OBJECTIVES: We developed a symptom-based measure of severity for chronic lung disease (CLD) that can be readily administered in ambulatory care settings and be used to supplement general health-related quality of life (HRQoL) assessments and pathophysiologic indicators in research and clinical care. DESIGN: Cross-sectional data from the Veterans Health Study, an observational study of health outcomes in patients receiving Veterans Affairs (VA) ambulatory care. SETTING: Four VA outpatient clinics. STUDY SUBJECTS: Two hundred ninety-two participants with CLD were identified on the basis of patient report of having a physician's diagnosis of chronic bronchitis, emphysema, or asthma and either using inhaled medications or having a productive cough on most days for 3 months. MEASUREMENTS AND RESULTS: Participants were scheduled for an in-person interview in which they completed a CLD questionnaire and measurements of peak expiratory flow rate (PEFR). They were also mailed an HRQoL questionnaire, the Short Form Health Survey (SF-36). The CLD questionnaire included six symptom items chosen by an expert panel (two items each for dyspnea, wheezing, and productive cough). The combination of these items yielded a CLD severity index that correlated significantly with all eight scales of the SF-36 (range of r, -0.19 to -0.37; p<0.01). In contrast, PEFR had statistically significant correlations only with two SF-36 scales: physical functioning and bodily pain. CONCLUSIONS: The CLD severity index is a reliable and valid patient-administered instrument that may be used to evaluate the effects of CLD on general HRQoL and predict future health services utilization.

Aged↗
PubMed1997

Carcinoma ex pleomorphic adenoma of the palate--a case report.

A case of squamous cell carcinoma ex pleomorphic adenoma in a palate is presented and comments on diagnostic criterias are described. The patient was 36-year-old male presenting with an ovoid elevated palate mass for 6 months. The tumor located in the junctional area of soft and hard palate. The mucosa was diffusely ulcerated and the mass focally tightly adherent to adjacent tissue. The initial cytologic and pathological diagnosis by fine needle aspiration biopsy and open biopsy was benign pleomorphic adenoma. After total removal, histologic examination revealed that tumor was composed partly of benign pleomorphic adenoma and partly of an squamous cell carcinoma component with areas of necrosis and capsular invasion. Immunohistochemical staining in the carcinoma area revealed positive reaction for low and high molecular weight cytokeratin, and epithelial membrane antigen, but negative for desmin, actin, GFAP and S-100 protein. In situ hybridization using biotinylated Epstein-Barr virus probe was done and the neoplastic cells were negative. Our case in an unusual partially encapsulated carcinoma ex pleomorphic adenoma in the palate and is not related in EBV infection.

Adenoma, Pleomorphic↗
PubMed1997

Hysteroscopy, hysterosalpingography and tubal ostial polyps in infertility patients.

OBJECTIVE: To compare the findings in infertility patients who underwent preoperative hysterosalpingography (HSG) followed by hysteroscopy and to determine the incidence of tubal ostial polyps, their HSG appearance and the results of hysteroscopic resection in our patient population. STUDY DESIGN: Sixty-eight infertility patients were evaluated by HSG followed by hysteroscopy. HSG diagnoses were divided into groups: group 1, normal; group 2, bilateral tubal occlusion; group 3, unilateral tubal occlusion; group 4, filling defects; and group 5, abnormal cavity. HSG findings were compared to the hysteroscopy findings. For patients in whom tubal ostial polyps were found, the findings were described, including postsurgical interval to conception. RESULTS: The agreement rates were 90%, 50%, 69%, 73% and 71% for groups 1-5, respectively. The positive predictive value of an abnormal HSG was 65%, and the negative predictive value of a normal HSG was 90%. Six of 68 patients (11.3%) had polyps at the fallopian tube ostium. Three of these patients (50%) had had the finding of proximal tubal occlusion on the ipsilateral side predicted by HSG; three had had normal HSGs. Four of the six conceived following polypectomy. The mean interval from surgery to conception was 4.5 months. CONCLUSION: HSG was a specific but not sensitive predictor of uterine pathology in our patient population. Tubal ostial polyps may occur in a significant proportion of infertility patients and can cause proximal tubal occlusion on HSG. Their possible contribution to infertility and clinical significance deserve further investigation.

Adult↗
PubMed1997

The role of Helicobacter species in newly recognized gastrointestinal tract diseases of animals.

Because Helicobacter pylori is now known to be a significant human pathogen, experimental animal models are increasingly being used to study the pathogenesis of this organism. Unfortunately, early studies failed to establish H. pylori in animal models, and surprisingly, Koch's postulates were initially fulfilled in two human volunteers. Germfree experiments performed in pigs and pups however established that H. pylori would colonize in these animals, and gastritis was induced. Certain macaque species and cats are now known to be naturally infected with H. pylori, and these animals are susceptible to experimentally induced infection with the organism as well. Interestingly, as the ability to manipulate and grow H. pylori in vitro increased, so did the ability to colonize it in animal models. Helicobacter pylori has now experimentally induced gastritis in germfree euthymic and nude mice and in conventionally housed mice. Six additional Helicobacter species have been isolated and identified from the stomachs of various mammals, including dogs, cats, ferrets, pigs, monkeys, and cheetahs; these organisms, similar to H. pylori, are associated with variable degrees of gastritis in their hosts. In addition to the discovery of gastric helicobacters, an increasing number of Helicobacter spp. have been isolated from the distal part of the gastrointestinal tracts of mammals and birds. Importantly, in one inbred strain of mice, A/JCr, persistent infection with H. hepaticus is linked to development of hepatic adenomas and adenocarcinomas. To date, the genus Helicobacter includes 17 named species as well as other formally unnamed closely related organisms. An overview of gastric helicobacters and naturally acquired Helicobacter spp.-induced disease in laboratory animals and, where appropriate, use of animal models to study H. pylori-associated gastric disease is presented. Similarities between Helicobacter infections and the epidemiology of the diseases induced by these bacteria in humans and animals also are highlighted.

Animals↗
PubMed1997

European regulations relevant to the marketing and use of fish vaccines.

In the Member States of the European Union (EU), vaccines cannot be marketed unless a marketing authorisation has been granted for the product by the relevant competent authority, and there are similar requirements in other European countries, such as Norway. The legal basis of this control in EU Member States is through the national implementation of the various directives and regulations, principally Council Directive 81/851/EEC as amended and Council Regulation (EEC) 2309/93. This Regulation also provides the framework for the decentralised system for authorisation of products in more than one member state and for the centralised procedure for authorisation in all of the countries of the EU. Council Directive 81/852/EEC as amended and EU guidance notes set out requirements for the quality, safety and efficacy of the vaccines. Only products which conform with the requirements can now be given an authorisation for marketing in a Member State, and all existing vaccines must be shown to conform by April 1998. Requirements for vaccines are also included in the monographs of the European Pharmacopoeia, which set legally binding standards for products on the market in Europe. Monographs for various types of fish vaccines are now being elaborated. In addition to control through marketing authorisations, a number of European countries have a system for official control of each batch which is to be released for sale. Distribution and supply of the products are also subject to controls. The system used varies from country to country but, for example, in some countries vaccines can only be supplied on receipt of a prescription from a veterinary surgeon. Thus, the marketing and use of fish vaccines are subject to a series of regulations which must be addressed by any company wishing to supply such products in Europe.

Animals↗
PubMed1996

Neutrophil elastase: a determinant of endothelial damage and reperfusion injury after liver transplantation?

Reperfusion injury has been implicated in the development of primary graft dysfunction (PGD) after liver transplantation. Neutrophil migration and activation may be involved in the pathogenesis of this injury. We studied neutrophil activation and its role in the etiology of PGD by measuring neutrophil elastase by radioimmunoassay, in serial blood samples of 19 patients before, during, and for 24 hr after transplantation. In a subgroup of patients, we also measured soluble thrombomodulin at the same time points as a marker of endothelial damage. The pretransplant elastase level was significantly raised (40.13+/-4.84 ng/ml, mean+/-SEM) compared with levels of healthy controls (18.7+/-5.6 ng/ml, P<0.05). A marked increase in elastase activity followed reperfusion, with a peak at 2 hr (370+/-50.5 ng/ml, P<0.01). Thereafter, there was a decline, but elastase remained elevated at 24 hr (186+/-60.94 ng/ml). The mean increase in neutrophil elastase after reperfusion correlated significantly with markers of graft function (P<0.05) and with the mean rise in soluble thrombomodulin (P=0.042), which increased from a pretransplant level of 81.2+/-11.32 to 186+/-50.4 ng/ml, 6 hr after reperfusion (P<0.05). The results of this study indicate that marked neutrophil activation and endothelial cell damage occurs after graft reperfusion during orthotopic liver transplantation, and the degree of activation correlates with markers of graft function, which may suggest a role in the etiology of PGD.

Biomarkers↗
PubMed1996

Distribution of alpha 2A-adrenergic receptor-like immunoreactivity in the rat central nervous system.

In this study, we analyzed immunohistochemically the distribution of the A subtype of alpha 2-adrenergic receptor (alpha 2A-AR) in the rat central nervous system using light level immunohistochemistry. By using affinity-purified antisera, we found perikaryal labeling was diffuse and/or punctate; immunoreactive puncta were heterogeneous in size and number in a region-specific manner. Dense deposits of immunoreaction product were found associated with neuropil also, particularly in the lateral parabrachial nucleus, locus coeruleus, lateral septum, diagonal band, stratum lacunosum-moleculare of CA1, and various nuclei of the amygdala and extended amygdala. Prominently immunoreactive olfactory structures include the anterior olfactory nucleus and the granular layer of the olfactory bulb. The cortex was generally light to moderately labeled with greater immunoreactivity in the cingulate and insular cortices. alpha 2A-AR-like immunoreactivity was intense in the basal forebrain and continuous from the nucleus accumbens through the substantia innominata and fundus of the striatum. Most immunoreactivity in the diencephalon was restricted to the hypothalamus with light to moderate labeling in the thalamus. Generally light immunoreactivity was observed in midbrain structures. In the pons and medulla, both perikaryal and neuropil labeling were observed. Together with the accompanying paper describing the neural distribution of alpha 2C-AR-like immunoreactivity, our results provide an extensive immunohistochemical cartography of alpha 2-ARs in the adult rat central nervous system.

Animals↗
PubMed1996

Distribution of alpha 2C-adrenergic receptor-like immunoreactivity in the rat central nervous system.

The distribution of alpha 2C-adrenergic receptors (ARs) in rat brain and spinal cord was examined immunohistochemically by using an affinity purified polyclonal antibody. The antibody was directed against a recombinant fusion protein consisting of a 70-amino-acid polypeptide portion of the third intracellular loop of the alpha 2C-AR fused to glutathione-S-transferase. Selectivity and subtype specificity of the antibody were demonstrated by immunoprecipitation of [125I]-photoaffinity-labeled alpha 2-AR and by immunohistochemical labeling of COS cells expressing the individual rat alpha 2-AR subtypes. In both cases the antibody recognized only the alpha 2C-AR subtype, and immunoreactivity was eliminated by preadsorption of the antibody with excess antigen. In rat brain, alpha 2C-AR-like immunoreactivity (alpha 2C-AR-LI) was found primarily in neuronal perikarya, with some labeling of proximal dendrites; analysis by confocal microscopy revealed the intracellular localization of some of the immunoreactivity. Areas of dense immunoreactivity include anterior olfactory nucleus, piriform cortex, septum, diagonal band, pallidum, preoptic areas, supraoptic nucleus, suprachiasmatic nucleus, paraventricular nucleus, amygdala, hippocampus (CA1 and dentate gyrus), substantia nigra, ventral tegmental area, raphe (pontine and medullary), motor trigeminal nucleus, facial nucleus, vestibular nucleus, dorsal motor nucleus of the vagus, and hypoglossal nucleus. Labeling was found in specific laminae throughout the cortex, and a sparse distribution of very darkly labeled cells was observed in the striatum. At all levels of the spinal cord there were small numbers of large, darkly labeled cells in layer IX and much smaller cells in layer X. In general, the pattern of alpha 2C-LI throughout the neuraxis is consistent with previously published reports of the distribution of receptor mRNA detected by hybridization histochemistry.

Animals↗
PubMed1996

Crystal structures of a complexed and peptide-free membrane protein-binding domain: molecular basis of peptide recognition by PDZ.

Modular PDZ domains, found in many cell junction-associated proteins, mediate the clustering of membrane ion channels by binding to their C-terminus. The X-ray crystallographic structures of the third PDZ domain from the synaptic protein PSD-95 in complex with and in the absence of its peptide ligand have been determined at 1.8 angstroms and 2.3 angstroms resolution, respectively. The structures reveal that a four-residue C-terminal stretch (X-Thr/Ser-X-Val-COO(-)) engages the PDZ domain through antiparallel main chain interactions with a beta sheet of the domain. Recognition of the terminal carboxylate group of the peptide is conferred by a cradle of main chain amides provided by a Gly-Leu-Gly-Phe loop as well as by an arginine side chain. Specific side chain interactions and a prominent hydrophobic pocket explain the selective recognition of the C-terminal consensus sequence.

Crystallography↗