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Biomedical subjects

B Sommer

Publications and source records attributed to B Sommer.

At least 109 records · Page 6Linked to original sources
PubMed1993

RNA editing of AMPA receptor subunit GluR-B: a base-paired intron-exon structure determines position and efficiency.

A functionally critical position (Q/R site) of the AMPA receptor subunit GluR-B is controlled by RNA editing that operates in the nucleus, since in brain and clonal cell lines of neural origin, unspliced GluR-B transcripts occur edited in the Q/R site CAG codon and, additionally, in intronic adenosines. Transfection of GluR-B gene constructs into PC12 cells revealed that the proximal part of the intron downstream of the unedited exonic site is required for Q/R site editing. This intron portion contains an imperfect inverted repeat preceding a 10 nt sequence with exact complementarity to the exon centered on the unedited codon. Single nucleotide substitutions in this short intronic sequence or its exonic complement curtailed Q/R site editing, which was recovered by restoring complementarity in the respective partner strand. Base conversion in the channel-coding region of GluR-B directed by base paired sequences may be executed by a ubiquitous nuclear adenosine deaminase specific for double-stranded RNA.

Adenosine Deaminase↗
PubMed1993

[Dog bite injuries with foreign body incorporation].

Dog-bite injuries represent a significant proportion of those injuries seen in a casualty department. Aside from primary wound management and determining the patient's vaccination status, X-ray examination is always indicated because of the possibility of foreign body inclusion as well as fractures. Plain X-ray views will reveal 88% of these foreign bodies. Our case involves a patient seeking workmen's compensation for a dog-bite injury and foreign body inclusion. Following removal of the foreign body, the patient was without symptoms and returned to his previous work.

Adult↗
PubMed1992

High-affinity kainate and domoate receptors in rat brain.

Mammalian brain expresses receptors which bind the potent neurotoxins, kainate and domoate, with high affinity, and which form a subclass of ionotropic glutamate receptors. A new member of these receptors, expressed in both adult and embryonic CNS is compared in its ligand binding properties to its closely sequence-related homologs.

Amino Acid Sequence↗
PubMed1992

A glutamate receptor channel with high affinity for domoate and kainate.

The non-NMDA family of glutamate receptors comprises a growing number of structurally related subunits (GluR-A to -D or -1 to -4; GluR-5, -6; KA-1). GluR-A to -D appear to constitute the major AMPA receptor subtypes but the functional and pharmacological characteristics of the other subunits are unresolved. Using a mammalian expression system we demonstrate here that homomeric GluR-5 receptors exhibit properties of a high affinity domoate (KD approximately 2 nM) and kainate (KD approximately 70 nM) binding site. For these receptors, the rank order of ligands competing with [3H]kainate binding was domoate much greater than quisqualate approximately glutamate much greater than AMPA approximately CNQX. The respective receptor channels were gated in decreasing order of sensitivity by domoate, kainate, glutamate and AMPA. In contrast to recombinantly expressed GluR-A to -D channels, currents elicited at GluR-5 receptor desensitize channels to all agonists. This property is characteristic of currents in peripheral neurons on sensory ganglia. These findings suggest the existence of at least two distinct types of non-NMDA receptor channels, both gated by AMPA and kainate, but differing in pharmacology and current properties.

Amino Acid Sequence↗
PubMed1992

The course of HIV disease in renal allograft recipients.

The clinical course of HIV seropositive renal allograft recipients is ill defined. Thus, a retrospective analysis of mortality, morbidity and graft survival was performed in two groups of HIV-positive patients. Group 1 (nine patients), seropositive for an indefinite period of time prior to transplantation (eight i.v. drug abusers, one homosexual), all lost their grafts after a mean period of 23 +/- 11 months from chronic rejection (six), complicated by focal glomerular sclerosis and nephrotic syndrome in three cases, sepsis (two) and death with a functioning graft (one). Four patients died, two from sepsis, one from Kaposi's sarcoma and one from fluid overload. Of the remaining five patients, all on hemodialysis, one had AIDS and four were asymptomatic after a mean period of 44 months following graft failure. Prolonged hospitalizations for both infections and acute rejection were common. Group 2 (six patients) seroconverted in the perioperative period, and two had functioning allografts at 78 and 100 months post-transplant. Causes of allograft loss, patient death and infection-related complications were similar to those of group 1, but acute rejection was rare. In conclusion, HIV infection in renal allograft recipients was associated with poor allograft survival due mainly to rejection, mostly chronic, often complicated by glomerular sclerosis and nephrotic syndrome. Infectious complications requiring hospitalization were also increased.

Adult↗
PubMed1992

Glutamate receptor channels: novel properties and new clones.

Glutamate is the principal excitatory neurotransmitter in the brain. Glutamate activates cation-selective receptor channels carried by nearly every neuron and by glial cells. Bernd Sommer and Peter Seeburg describe how our concepts concerning the molecular and functional design of ionotropic glutamate receptors are rapidly progressing, with the recent discovery of novel receptor properties and new subunits following the landmark cloning of the first receptor subunit by M. Hollmann and his colleagues. New properties currently revealed by the cloned receptor channels may guide physiologists in characterizing the elementary steps in synaptic transmission, help neurologists to define the role of glutamate receptors in acute and chronic neuropathologies, and enlighten all neuroscientists whose models for learning and memory involve the idiosyncracies of particular channel subtypes.

Amino Acid Sequence↗
PubMed1992

Glutamate-gated ion channels in the brain. Genetic mechanism for generating molecular and functional diversity.

L-glutamate is the major excitatory neurotransmitter in the vertebrate central nervous system. Most cells are responsive to glutamate which activates cation channels with different pharmacological, kinetic, and ion permeability properties. These channels play important roles in neurotransmission, memory acquisition as well as acute and chronic disorders of the brain. The present report summarizes recent knowledge on AMPA (a-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid) receptors which mediate fast synaptic neurotransmission.

Animals↗
PubMed1992

AANA journal course: update for nurse anesthetists--managing human immunodeficiency virus and acquired immune deficiency syndrome during anesthesia care.

The human immunodeficiency virus (HIV) and its advanced progression to acquired immune deficiency syndrome (AIDS) has had a greater impact on our society than any other disease entity during this century. Throughout the past decade the prevalence of HIV disease has grown to pandemic proportions throughout many regions of the world. The infectious and often fatal nature of HIV has made AIDS the most threatening epidemic currently facing modern medicine. A myriad of fears concerns, challenges, and frustration face all healthcare providers whose awareness and impact on practice is continuously challenged. Every nurse anesthetist is responsible for maintaining the ability to both prevent HIV disease transmission and appropriately care for HIV-infected patients during anesthesia care. Experience throughout the past decade of a continuously increasing prevalence of both HIV and AIDS has provided a wealth of information and knowledge that continues to enhance patient care. The following AANA Journal Course will present a current overview of HIV disease and considerations for providing quality anesthesia care while preventing disease transmission.

Body Fluids↗
PubMed1992

What issues and procedures should concern you as a CRNA manager when a CRNA employee has been diagnosed as HIV positive?

Today's manager is faced with a multitude of issues regarding the HIV-infected health-care provider. A well-planned and organized response to such a situation can best meet both employer and provider needs. The manager should possess the knowledge to both respond appropriately and utilize the necessary resources in accommodating the HIV-infected employee. Recommendations are made to consider should this situation present.

Ethics, Nursing↗
PubMed1991

[Clinical value of ultrasonography and computerized tomography prior to abdominal interventions].

We studied the value of ultrasound and computed tomography in the preoperative diagnosis of abdominal diseases in 100 patients. Reference methods were the reports of surgery and pathology. A computed tomography or ultrasound diagnosis could be correct or false and was considered uncertain, if the main diagnosis was missed but computed tomography or ultrasound suspected pathology, which then could be clarified by other procedures. Overall, computed tomography was superior with 75 correct, 13 false and 12 uncertain diagnoses compared to ultrasound with 58 correct, 31 false and 11 uncertain diagnoses. Ultrasound often failed because obesity or gas impaired visibility. If only cases without technical problems of ultrasound were taken into account, diseases of liver, gallbladder, pancreas, kidney, the adrenal region and other abdominal masses were equally well diagnosed by ultrasound and computed tomography. As expected, the diagnostic value of both modalities was markedly reduced in diseases of the bile duct and the gastrointestinal tract. Because the study design required both, ultrasound and computed tomography, cases already clarified by ultrasound were not included. This fact might have further reduced the sensitivity of ultrasound in comparison to computed tomography. Furthermore, ultrasound was mostly one of the first diagnostic procedures performed right after the patient's admission with little information on anamnestic and clinical data. The information given prior to computed tomography was in general more detailed.

Adult↗