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Biomedical subjects

J Kincaid

Publications and source records attributed to J Kincaid.

13 recordsLinked to original sources

Characterization and epidemiologic subtyping of Shiga toxin-producing Escherichia coli strains isolated from hemolytic uremic syndrome and diarrhea cases in Argentina.

Argentina has a high incidence of hemolytic uremic syndrome (HUS); 12.2 cases per 100,000 children younger than 5 years old were reported in 2002. Shiga toxin (Stx)-producing Escherichia coli (STEC) is the primary etiologic agent of HUS, and STEC O157 is the predominant serogroup isolated. The main objective of the present work was to establish the phenotypic and genotypic characteristics of the STEC strains in general isolated from Argentine children during a prospective study and the clonal relatedness of STEC O157:H7 strains using subtyping techniques. One hundred and three STEC strains isolated from 99 children were included. The phenotypic and genotypic features were established, and a polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) was performed to determine stx2 variants. The clonal relatedness of E. coli O157 isolates was established by phage typing and pulsed-field gel electrophoresis (PFGE). The 103 STEC strains belonged to 18 different serotypes, and 59% were of serotype O157:H7. Stx2 was identified in 90.3%, and stx1 in 9.7%. Among the 61 STEC O157 strains, 93.4% harbored the stx2/stx2vh-a genes; PT4 (39.3%) and PT2 (29.5%) were the predominant phage types. Using PFGE with the enzyme XbaI, a total of 41 patterns with at least 80% similarity were identified, and seven clusters with identical profiles were established. Some of the clusters were further split by PFGE using BlnI as the second enzyme. Isolates with indistinguishable PFGE patterns were with one exception also indistinguishable by phage typing and stx genotyping. These findings confirmed that some isolates were genetically related. However, no epidemiological linkages were identified. STEC strains with different genotypes and belonging to diverse serotypes were isolated in Argentina. Some STEC O157 strains could not be distinguished by applying subtyping techniques such as PFGE and phage typing.

Argentina↗

PulseNet USA: a five-year update.

PulseNet USA is the molecular surveillance network for foodborne infections in the United States. Since its inception in 1996, it has been instrumental in detection, investigation and control of numerous outbreaks caused by Shiga toxin-producing Escherichia coli O157:[H7] (STEC O157), Salmonella enterica, Listeria monocytogenes, Shigella spp., and Campylobacter. This paper describes the current status of the network, including the methodologies used and its future possibilities. The currently preferred subtyping method in the network is pulsed-field gel electrophoresis (PFGE), a proven highly discriminatory molecular subtyping method. New simpler sequencebased subtyping methods are under development and validation to complement and eventually replace PFGE. PulseNet is essentially a cluster detection network, but the data in the system will now also be used in attribution analyses of sporadic infections. The PulseNet platform will also be used as a primary tool in preparedness and response to acts of food bioterrorism.

Bacterial Typing Techniques↗

Structure-activity relationships of a series of pyrrolo[3,2-d]pyrimidine derivatives and related compounds as neuropeptide Y5 receptor antagonists.

Neuropeptide Y (NPY) has been shown to play an important role in the regulation of food intake and energy balance. Pharmacological data suggests that the Y5 receptor subtype contributes to the effects of NPY on appetite, and therefore a Y5 antagonist might be a useful therapeutic agent for the treatment of obesity. In attempts to identify potential Y5 antagonists, a series of pyrrolo[3, 2-d]pyrimidine derivatives was prepared and evaluated for their ability to bind to Y5 receptors in vitro. We report here the synthesis and initial structure-activity relationship investigations for this class of compounds. The target compounds were prepared by a variety of synthetic routes designed to modify both the substitution and the heterocyclic core of the pyrrolo[3,2-d]pyrimidine lead 1. In addition to identifying several potent Y5 antagonists for evaluation as potential antiobesity agents, a pharmacophore model for the human Y5 receptor is presented.

Anti-Obesity Agents↗

Cable grafting of the spinal accessory nerve after radical neck dissection.

BACKGROUND: From January 1981 through March 1996, 20 patients with head and neck cancer underwent radical neck dissection with sacrifice of the spinal accessory nerve and immediate reconstruction of the nerve using a microsurgical technique and a cable graft of the great auricular nerve. METHODS: Postoperative shoulder function was assessed via a subjective questionnaire, objective strength testing, and/or postoperative electromyography. The latter was used to evaluate for the presence and amplitude of voluntary motor potentials, the presence of fibrillation potentials, and nerve conduction latency. The group of patients who underwent cable grafting of the spinal accessory nerve was compared with a group of patients who underwent modified radical neck dissection with preservation of the spinal accessory nerve and with another group of patients who underwent a classic neck dissection with sacrifice of the spinal accessory nerve and no reconstruction. RESULTS: In terms of shoulder function, the group of patients in whom the spinal accessory nerve was reconstructed occupied an intermediate position; ie, their postoperative shoulder function was better than that of the patients who underwent radical neck dissection without reconstruction but not as good as that of the patients who underwent modified neck dissection with preservation of the spinal accessory nerve. CONCLUSION: Cable grafting of the spinal accessory nerve that has been sacrificed during radical neck dissection results in improved shoulder function in the postoperative period.

Accessory Nerve↗

Identification and characterization of a novel endothelin receptor that binds both ETA- and ETB-selective ligands.

This study demonstrates the presence of a novel endothelin (ET) receptor subtype that displays high affinity for both ETA- and ETB-selective ligands. This subtype has been identified in canine spleen membranes using ETB-selective agonists ET-3, IRL-1620, sarafotoxin 6c (S6c) as well as ETA-selective antagonists BQ123 and related cyclic pentapeptides. Binding of 125I-ET-3 to canine spleen membranes was specific and saturable with an apparent dissociation constant of 130 pM and maximum binding (Bmax) of 240.0 fmol/mg protein. Although the apparent affinities obtained with 125I-ET-1 and 125I-ET-3 were comparable (90 and 130 pM, respectively), the maximum binding obtained with 125I-ET-3 was approximately 35% of that obtained with 125I-ET-1, which indicates that canine spleen possesses both ETA and ETB receptors in the ratio 65:35. Competition binding experiments using 125I-ET-3 and unlabeled ET-1, ET-3, S6c, and IRL-1620 suggested that although ET-1 and ET-3 displayed similar high affinity, S6c and IRL-1620 were 20-300-fold weaker than ET-1 and ET-3 in competing for 125I-ET-3 binding to canine spleen membranes. In addition, BQ123, an ETA-selective antagonist, displaced 125I-ET-3 binding from canine spleen with an IC50 value of 30 nM. Similar profiles were obtained with related cyclic pentapeptides. Electrophysiological studies performed on Xenopus laevis oocytes injected with canine spleen poly(A)+ RNA indicated that the ETB receptor present in these tissues is functional and displays the same pharmacology as that observed in binding studies using these membranes. As a comparison, both binding and functional studies were performed in canine lung and the data indicate that the ETB receptor present in this tissue is similar to that of the cloned human ETB receptor but different from that present in canine spleen. These observations were further confirmed by performing cross-linking experiments on these membranes. Although canine lung and cloned human ETB receptors displayed the same molecular weight bands with similar pharmacology, canine spleen ETB receptors displayed different molecular weight bands and different pharmacology. In addition, the ETB receptors present in canine spleen were also identified in canine bladder, monkey spleen and human spleen. Thus, the data presented in this manuscript provide evidence for the presence of a novel ETB receptor in different tissues as well as different species including human.

Animals↗

Nature, nurture, nutrition: interdisciplinary programs to address the prevention of malnutrition and dehydration.

Malnutrition and dehydration are common problems in nursing home patients. One explanation for this may be the large number of patients requiring feeding assistance. The Dysphagia Team at the Department of Veterans Affairs Medical Center in Miami, Florida served as the primary source in the expansion of a nutritionally supportive environment to assist in the prevention of malnutrition and dehydration in patients with feeding/swallowing disorders. "Silver Spoons," a program in which volunteers provide supervised feeding, "Happy Hour," a time each day during which an atmosphere is provided that encourages socialization and hydration, and "Second Seating," during which lunch is provided for patients who require modification of eating style, food texture, or timing are described. Analysis of the program's outcomes show it to be timely, pleasing to patients, and cost-effective.

Aged↗

Brain mapping techniques to maximize resection, safety, and seizure control in children with brain tumors.

Intraoperative brain mapping techniques were used to localize language cortex, sensorimotor pathways, and seizure foci in children with supratentorial brain tumors. The methods of direct cortical and subcortical stimulation, in addition to electrocorticography, enabled us to maximize tumor resection, minimize morbidity, and eradicate epileptogenic zones which were always adjacent to, but not involving, the tumor nidus. Language localization was found to be quite variable in the children tested and anatomically unpredictable based on the preoperative neurological or radiological examination. Physiological mapping techniques, therefore, appear to be safe, reliable, and very useful for operations on tumors located within or adjacent to eloquent brain regions in the pediatric population.

Adolescent↗

Thymic carcinoid with cutaneous hyperpigmentation.

Carcinoid tumors of the thymus gland have occasionally been associated with endocrine hyperfunction. A case of thymic carcinoid was initially observed as Cushing's syndrome and was also associated with marked hyperpigmentation. While the hyperpigmentation may be related to the excessively high levels of corticotropin, it is also possible that thymic carcinoids could produce melanocyte-stimulating hormone-like (or beta-lipotropin) material.

Carcinoid Tumor↗

Bilateral retinal arteritis with multiple aneurysmal dilatations.

The authors have reported two cases of bilateral retinal arteritis with multiple aneurysmal dilatations. Despite comprehensive medical evaluation, no clear etiology was identified, although polyarteritis (periarteritis) remains a possibility. These cases constitute an unusual and unique manifestation of inflammatory retinal vascular disease.

Adult↗

Cerebrospinal fluid immunoelectrophoresis in multiple sclerosis.

In 95 patients with definite multiple sclerosis (MS) cerebrospinal fluid (CSF) cytomorphology, protein electrophoresis and immunoelectrophoresis using antisera to human serum, Fab fragments of immunoglobulin G(IgG) and to kappa and lambda light chains and the CSF IgG concentration were examined. In the CSF diagnosis of MS, the set of the examinations used is considered to be superior to any individual laboratory technique currently applied in the diagnostic process of MS. In the set of the CSF examinations, CSF immunoelectrophoresis revealed abnormal findings in patients with MS in whom presence of bands (oligoclonal gammopathy) in the gamma-globulin field of the CSF electropherogram and/or increased concentration of CSF IgG were not demonstrated.

Adult↗

Absence of heme-localized strain in T state hemoglobin: insensitivity of heme-imidazole resonance Raman frequencies to quaternary structure.

Substitution of pentadeuterated 2-methylimidazole in (2-methylimidazole)-Fe(II)-protoporphyrin IX, a model complex for deoxyHb, shifts three bands in the low-frequency resonance Raman spectrum 380 leads to 373 cm-1, 348 leads to 345 cm-1, and 220 leads to 218 cm-1. The first of these is assigned primarily to Fe-imidazole stretching, and the other two are assigned to porphyrin deformation modes with substantial Fe-pyrrole stretching contributions. The three bands are observed in deoxyHb and Mb. The Fe-pyrrole modes are at essentially the same frequencies in the two proteins, but the Fe-imidazole mode is 6 cm-1 lower in deoxyHb than Mb, implying a slight alteration in the heme-imidazole linkage. No change greater than 2 cm-1 is observed when Hb Kempsey is switched from the R to the T state. This observation places an upper limit on the energy stored in the Fe-imidazole bond of T state deoxyHb, which is estimated to be less than 0.2 kcal/mol (less than 836.8 J/mol).

Chemical Phenomena↗