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Biomedical subjects

R Galbraith

Publications and source records attributed to R Galbraith.

10 recordsLinked to original sources

Heme oxygenase: who needs it?

Heme is a molecule that is synthesized by the sequential actions of eight enzymes and is ubiquitous throughout nature. For many years it has been known that heme is also catabolized to yield biliverdin (which is subsequently reduced to bilirubin), one atom of iron, and one molecule of carbon monoxide. There has been a recent explosion of interest in this degradative process that is catalyzed by the rate-limiting enzyme, heme oxygenase. In particular, there has been a special interest in the potential physiological and pathological roles that may be played by these breakdown products. This minireview will examine some of these potential functional correlates, with special emphasis on potential oxidant and antioxidant effects of the bilirubin, carbon monoxide, and iron that result from the activity of heme oxygenase.

Animals↗

Results of temporal lobectomy for the treatment of partial complex epilepsy.

Epilepsy is the third most common cause of neurologic disability. The disease carries a 15 prevalence and a 3.5% lifetime risk. Seventy percent of patients can achieve good seizure control with medication. The remaining 30%, some 360,000 people across the United States, have intractable epilepsy and would benefit from evaluation at an epilepsy specialty center where surgical intervention is an option. The following report reviews a series of 50 patients referred to the Arkansas Comprehensive Epilepsy Program for treatment of intractable complex partial epilepsy. In this series, we evaluate results of temporal lobectomy, commenting upon factors in the patients' histories which may influence their outcomes.

Adolescent↗

The effect of dimethyl sulfoxide on heme synthesis and the acute phase reaction in human HepG2 hepatoma cells.

Effects of DMSO on heme synthesis and enzymes of the heme biosynthetic pathway were examined in human HepG2 hepatoma cells. HepG2 cells contain measurable levels of ALA synthase and ALA dehydratase, and their levels are increased after treatment of cells with DMSO. DMSO treatment also led to increases in heme content and the synthesis of haptoglobin, while it decreased the synthesis of albumin and AFP. Changes in plasma protein synthesis after DMSO treatment are characteristic of those known to occur in the acute phase reaction. These findings suggest that profound changes in heme synthesis may occur during the acute phase reaction.

5-Aminolevulinate Synthetase↗

Interaction of Gc (vitamin-D binding protein) with membrane of activated natural cytolytic cells.

Gc (a vitamin D binding protein) has been speculated to play a role in the function of immune response, yet, it has not been examined for its biological response properties. Therefore, we tried to (a) characterize the appearance of membrane bound Gc (mGc) on non-activated and mitogen activated lymphocytes as well as on Interleukin-2 activated killer cells and (b) examine the role of serum isolated human Gc on human blastogenesis and cytotoxicity (natural killing and lymphokine-activated killing). Our data suggests that activated cells possess a greater number of cells with mGc than non-activated cells and that as a biological response modified we find modulation of blastogenesis and cytotoxicity to be consistently but not very significantly down-regulated. Anti-Gc antibody was observed to significantly inhibit NK activity.

Cell Membrane↗

Evidence for substance P as a functional neurotransmitter in guinea pig small intestinal mucosa.

We showed previously that electrical transmural stimulation (TS) of guinea pig jejunal mucosa in vitro released neurotransmitters from submucosal plexus neurons which caused alterations in ion transport. The present studies were performed to obtain information regarding the identity of the neurotransmitters. The addition of exogenous substance P (SP) to the serosal side of the tissue caused a transient increase in short-circuit current (Isc) which closely mimicked the response to TS. Both TS and SP caused net secretion of Cl- ions by stimulating movement toward the luminal side. Tetrodotoxin abolished the response to TS, inhibited approximately 70% of the response to SP but did not affect the response to urecholine, a cholinergic muscarinic agonist. In the presence of the muscarinic antagonist, atropine, Isc responses to both TS and SP were reduced suggesting that a portion of both responses was due to action on enteric nerves causing release of acetylcholine. Following desensitization of the tissue with supramaximal doses of SP the response to TS was significantly reduced but the response to urecholine was unchanged. In the presence of atropine, SP desensitization reduced the nerve-stimulated response by approximately 65%; treatment of tissue with SP antibodies reduced the response by approximately 55%. Under the same conditions Isc responses to histamine were unaltered. Our results suggest that both SP (or a structurally analogous neurotransmitter) and acetylcholine as well as additional unidentified neurotransmitter(s) are functionally important in the regulation of intestinal ion transport in guinea pig jejunum.

Animals↗

High-resolution magnetic resonance imaging of the wrist: normal anatomy.

Magnetic resonance imaging (MRI) provided adequate depiction of carpal soft tissue structures in normal volunteers, as well as accurate anatomic correlation with cadaveric specimens. Using a high field strength system and surface coil techniques, the intricate anatomy of the wrist was best defined on long TR short TE images. However, from a practical view, T1 weighted images (TR 600 ms, TE 25 ms) were most useful because of short imaging times, satisfactory image quality, and the absence of motion artifacts. The coronal plane provided the clearest definition of important structures. Potential diagnostic limitations exist due to the inability of MRI to clearly delineate articular cartilage, joint capsules, and small interosseous ligaments. The presence of intra-articular fluid in both living subjects and cadaveric specimens, however, allowed for fine depiction of these structures on T2 weighted images.

Humans↗