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Biomedical subjects

D Martin

Publications and source records attributed to D Martin.

At least 577 records · Page 32Linked to original sources
PubMed1991

Autoreceptor regulation of glutamate and aspartate release from slices of the hippocampal CA1 area.

Slices of hippocampal area CA1 were employed to test the hypothesis that the release of glutamate and aspartate is regulated by the activation of excitatory amino acid autoreceptors. In the absence of added Mg2+, N-methyl-D-aspartate (NMDA)-receptor antagonists depressed the release of glutamate, aspartate, and gamma-aminobutyrate evoked by 50 mM K+. Conversely, the agonist NMDA selectively enhanced the release of aspartate. The latter action was observed, however, only when the K+ stimulus was reduced to 30 mM. Actions of the competitive antagonists 3-[(+/- )-2-carboxypiperazin-4-yl]-propyl-l-phosphonic acid (CPP) and D-2-amino-5-phosphonovalerate (D-AP5) differed, in that the addition of either 1.2 mM Mg2+ or 0.1 microM tetrodotoxin to the superfusion medium abolished the depressant effect of CPP without diminishing the effect of D-AP5. These results suggest that the activation of NMDA receptors by endogenous glutamate and aspartate enhances the subsequent release of these amino acids. The cellular mechanism may involve Ca2+ influx through presynaptic NMDA receptor channels or liberation of a diffusible neuromodulator linked to the activation of postsynaptic NMDA receptors. (RS)-alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, a selective quisqualate receptor agonist, and kainate, an agonist active at both kainate and quisqualate receptors, selectively depressed the K(+)-evoked release of aspartate. Conversely, 6-cyano-7-nitro-quinoxaline-2,3-dione, an antagonist active at both quisqualate and kainate receptors, selectively enhanced aspartate release. These results suggest that glutamate can negatively modulate the release of aspartate by activating autoreceptors of the quisqualate, and possibly also of the kainate, type. Thus, the activation of excitatory amino acid receptors has both presynaptic and postsynaptic effects.

Animals↗
PubMed1991

A controlled study of disruptive vocalizations among geriatric residents in nursing homes.

This paper reports the results of a controlled study comparing geriatric residents in nursing homes who displayed disruptive vocalizations with residents in a comparison group. Two 350-bed nursing homes were surveyed, and it was found that 11% of the residents engaged in disruptive vocalizations, at least once per week, of sufficient severity to require consideration in the resident's care plan. Results show that disruptive vocalizers were more functionally impaired and were more likely to receive a diagnosis of dementia. They were also more likely to display a higher activity level and to experience sleep disturbance and to be prescribed neuroleptic medications. Descriptive data are presented on typology of disruptive vocalizations, likely situations for their occurrence, and the utilization and perceived efficacy of common interventions. Suggestions are made regarding behavioral treatments for this vexing problem.

Activities of Daily Living↗
PubMed1991

Renal extracorporeal shock wave lithotripsy performed in patient with implantable cardioverter defibrillator.

The effect of extracorporeal shock wave lithotripsy on the automatic implantable cardioverter defibrillator is unknown. To evaluate what effect might occur, a non-implanted automatic implantable cardioverter defibrillator was subjected to a full course of extracorporeal shock wave lithotripsy while inactive. Bench testing by the manufacturer after lithotripsy demonstrated normal function of the device. A patient with an automatic implanted cardioverter defibrillator who required contralateral extracorporeal shock wave lithotripsy then underwent this procedure. The right renal calculus was destroyed successfully with no apparent damage to the automatic implantable cardioverter defibrillator. A test of the automatic implantable cardioverter defibrillator after lithotripsy demonstrated normal sensing and conversion of induced ventricular tachycardia.

Aged↗
PubMed1991

Identification of a surface-exposed immunodominant epitope on outer membrane protein P1 of Haemophilus influenzae type b.

Eight murine monoclonal antibodies (MAbs) directed against outer membrane protein P1 of Haemophilus influenzae type b were generated and characterized. Seven of the eight MAbs reacted with recombinant P1 and purified P1 protein from H. influenzae type b strains MinnA and 1613; MAb P1.8 was specific for the latter strain. A panel of 32 nontypeable and 140 encapsulated Haemophilus strains recovered worldwide representing the major clonal families of serotypes a, b, and d was used to evaluate the distribution among Haemophilus strains of the epitopes identified by the P1-specific MAbs. The epitope reactive with the seven MAbs which recognized P1 from strains MinnA and 1613 was shared by 92% of the encapsulated Haemophilus isolates tested. The epitope is present in the H. influenzae type b strains from clonal families commonly recovered from cases of invasive disease in North America and Europe. A series of nested 5' and 3' deletions of the P1 gene were constructed and analyzed to localize the determinants on P1 recognized by the MAbs. MAbs P1.2, P1.4, P1.5, P1.6, and P1.7 recognized an epitope localized to the carboxy-terminal portion of P1. Murine MAbs P1.1 and P1.3 and two human MAbs, HiH-7 and HiH-10, recognized a complex epitope which was partially localized to the carboxy-terminal portion of the P1 protein. These data indicate that an immunodominant surface-exposed epitope is present on the carboxy-terminal portion of the P1 protein of type b Haemophilus isolates responsible for the majority of invasive disease in North America.

Amino Acid Sequence↗
PubMed1991

Mapping of B-cell epitopes on the outer membrane P2 porin protein of Haemophilus influenzae by using recombinant proteins and synthetic peptides.

The P2 protein of Haemophilus influenzae type b has a porin activity and is the most abundant protein in the outer membrane. We have employed fusion protein constructs and synthetic peptides along with monoclonal antibodies to map B-cell epitopes in this protein. A linear, surface-exposed epitope was identified between residues 158 and 174. A second surface-exposed epitope was identified near the carboxy-terminal end of the protein (residues 319 to 341). Two additional B-cell epitopes were identified. One was localized between residues 28 and 55, whereas the other was located between residues 148 and 174. These epitopes were not present on the surface of intact H. influenzae cells. Thus, four distinct immunogenic and antigenic regions on the P2 protein have been identified.

Amino Acid Sequence↗
PubMed1991

Bite wounds to the upper extremity.

The complications secondary to mismanaged or neglected bite wounds to the upper extremity can be devastating to upper extremity functioning. An organized approach to treatment can prevent infection and permanent disability.

Animals↗
PubMed1991

Techniques for modelling population-related roster databases.

"In this paper the refinement and application of a technique for the generation of surface models of population and related information are examined.... The resulting database facilitates a range of improved spatial analyses. Some of these are more flexible means of accomplishing conventional tasks, such as the computation of incidence rates and the estimation of population for nonstandard areal units. Additionally, surface concepts are able to support innovative techniques, such as the identification and characterization of discrete settlements. Applications are described which demonstrate the range of possible analyses." The technique is illustrated using data for the United Kingdom.

Demography↗
PubMed1991

Biological activity of a human monoclonal antibody to Bordetella pertussis lipooligosaccharide.

The heterohybridoma cell line HBp2 secreting human monoclonal antibody (hMAb) directed against Bordetella pertussis was generated by fusing SP2/HPT heteromyeloma cells with human spleen lymphocytes, after in vitro stimulation for 6 days. The hybridoma was maintained in culture for more than 1 year with continuous antibody secretion. The hMAb HBp2, an IgM, reacted with untreated and proteinase K-treated B. pertussis outer membrane antigens, whereas the reactivity was lost when the antigen was treated with sodium periodate. Human MAb HBp2 was shown to be specific to B. pertussis LOS by immunoblotting of whole cell extracts after SDS-PAGE. In a dot enzyme immunoassay, HBp2 reacted with all B. pertussis strains and clinical isolates tested except for four atypical variant strains of the LOS B phenotype. Human MAb HBp2 also reacted with a clinical isolate of B. bronchiseptica. No reaction was observed against B. parapertussis and other gram-negative species. Together these studies suggested that HBp2 is reactive with carbohydrate epitopes present on the LOS A. Binding assays with live bacteria demonstrated that hMAb HBp2 reacted with cell surface exposed epitopes on B. pertussis but the antibody did not bind significantly to the surface on intact B. bronchiseptica cells. When examined for bactericidal activity in the presence of complement, hMAb HBp2 showed high lytic capability against B. pertussis while no killing was obtained against B. bronchiseptica. These experiments established that LOS A is a target for human bactericidal antibodies. This antigen merits further investigation as a potentially important component in human immunity to B. pertussis infection.

Antibodies, Bacterial↗
PubMed1991

[Surgical treatment of mature extracephalic vascular malformations (excluding portwine hemangioma). Experience of this department].

The department's experience of mature extracephalic vascular malformations shows that, regardless of the site and the type of the lesion, only surgical excision is able to ensure a good result for vascular malformations of the limbs. The results were almost always excellent and only the diffuse forms benefitted from preoperative sclerosant injections. Palliative treatments such as elastic compression still have a place in these indications. Arterial embolisations are only of limited value, particularly when they are selective, as a complement to surgery (risk of necrosis in peripheral lesions). All sites may be observed, but the authors particularly emphasise perineoscrotal lymphangiomatous lesions. Recurrences do occur, but are rare when the lesion is widely resected and a good quality reconstruction is performed.

Arm↗
PubMed1991

[Internal plantar flap on external plantar pedicle: a technique for the coverage of the whole surface of the foot. Initial report].

The authors present a new type of the classical medial plantar flap which derives its main blood supply from the medial plantar artery, a terminal branch of the posterior tibial artery. Our approach concerning flap dissection has not been modified, but the vascular supply of the flap has been shifted and a reverse blood flow coming from the lateral plantar artery is created after dividing the posterior tibial artery just proximal to its distal bifurcation. The reverse flow medial plantar artery island flap survival is ensured by rich anastomoses that usually occur between the dorsalis pedis and lateral plantar arteries. However, the venous return is also ensured by a reverse flow as in the case of lateral plantar artery. In addition, this flap presents a wide arc of rotation that is suitable for a variety of local defects, allowing cover of the foot. This new technique mainly provides a perfect indication for cover of distal weight bearing area defects of the foot when the distally based plantar flap is not possible for anatomical aberrations and/or in the presence of an unreliable blood supply of the flap itself. Moreover, it deserves a general description of a new type of flap pedicle design that we denote by the term "reverse flow Y-V extended flap pedicle". We intend to provide the readers with more details concerning clinical applications of this new surgical procedure.

Adult↗
PubMed1991

[Aneurysm rupture and cocaine addiction].

We describe a new case in which cocaine use was related to stroke and review the literature. Cocaine is increasingly used by drug addicts. The neurological complications are unpredictable. They include generalized or partial epileptic seizures, ischaemic or haemorrhagic cerebral vascular accident. In this case, stroke after intravenous drug injection is associated with rupture of an intra-cranial aneurysm. We put the accent on the difficulties to diagnose the cerebral stroke in cocaine abusers.

Adult↗
PubMed1991

Surgery for endometriosis.

Advanced operative laparoscopy in general, and videolaseroscopy using CO2 laser via operative channel of the laparoscope and video, specifically, has revolutionized the management of endometriosis. Adhesion formation is reduced and subsequent fertility rates exceed those obtained with laparotomy. The most complicated cases of endometriosis, including involvement of the rectovaginal septum, gastrointestine, and urinary tract, can now be treated endoscopically by an experienced operative laparoscopist.

Abdominal Neoplasms↗