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Biomedical subjects

R Grant

Publications and source records attributed to R Grant.

12 recordsLinked to original sources

Anaphylaxis from administration of intravenous thiamine.

The routine administration of intravenous thiamine in the emergency department has become widespread. Although anaphylaxis from intravenous thiamine is felt to be uncommon, it can be life threatening. The authors present such a case and review the literature regarding this clinical entity. This case of anaphylactic reaction appears to be the first instance reported since 1946 in the US literature. However a review revealed that cases of anaphylaxis from thiamine have been reported with some regularity in the non-US literature. Given the large number of patients treated without side effects, it seems that thiamine is relatively safe. However, this case illustrates that the assumption that thiamine is a drug with a completely innocuous nature is not totally accurate.

Adult

Roles of rpoD, spoIIF, spoIIJ, spoIIN, and sin in regulation of Bacillus subtilis stage II sporulation-specific transcription.

Bacillus subtilis strains containing defects in the sporulation gene spoIIF (kinA), spoIIJ (kinA), or spoIIN (ftsA) cannot transcribe the sigma E-dependent gene spoIID. Results presented here and by other workers demonstrate that the spoIIF, spoIIJ, and spoIIN gene products control spoIID transcription indirectly by coordinating the induction of the spoIIGAB, spoIIE, and spoIIAC operons, which are required for sigma E synthesis and processing. Sporulation competence and spoIIGAB, spoIIE, and spoIIAC transcription were restored in spoIIF, spoIIJ, and spoIIN mutants by introduction of crsA47, a mutation in the major vegetative sigma factor sigma A. crsA mutations are known to restore sporulation in certain spo0 mutants. crsA suppression of kinA and ftsA mutations was achieved through inhibition of the transcription of sin, a gene involved in the selection between several post-exponential-phase cell states. A deletion of sin restored sporulation competence in spoIIF, spoIIJ, or spoIIN mutant strains. A sin deletion was also able to restore sporulation competence in the crsA suppressible stage 0 mutant spo0K141.

Bacillus subtilis

Clinical outcome in aggressively treated meningeal gliomatosis.

We reviewed 11 consecutive patients with an antemortem cytologic diagnosis of meningeal gliomatosis. In three patients, meningeal gliomatosis was diagnosed before surgical resection of the glioma. Three of five patients with anaplastic astrocytoma and one with oligodendroglioma improved with treatment. Patients with glioblastoma multiforme did not respond and had a median survival from the diagnosis of meningeal gliomatosis of only 8 weeks. Meningeal gliomatosis can be an early finding in gliomas. Treatment response is probably related to tumor histology and grade.

Adolescent

A primary culture system of adult rat heart cells for the study of toxicologic agents.

Tricyclic antidepressants (TCAs) are currently used in the treatment of mental depression and nocturnal enuresis. Clinically, these drugs are useful; however, cardiotoxicity can occur even with therapeutic dosages. For example, TCAs are known to alter myocardial function, induce arrhythmias, and produce heart block in individuals with a normal cardiovascular history. The present study was undertaken to establish a culture system of spontaneously contracting adult primary myocardial cells for toxicologic testing and to examine their contractility, morphology, and lactate dehydrogenase release (LDH) after treatment with one of the most cardiotoxic TCAs, amitriptyline. Primary myocardial cell cultures were obtained from approximately 60- to 90-day-old Sprague-Dawley rats. After the cells had been grown in culture for 11 days, they were treated with amitriptyline (1 x 10(-3), 1 x 10(-4), and 1 x 10(-5) M) for 2 to 24 h. The highest concentration of amitriptyline (1 x 10(-3) M) completely destroyed the cardiac muscle cells. In addition to moderate and severe vacuole, granule, and pseudopodia formation, all contractile activity was inhibited as early as 2 h after exposure to the intermediate concentration of 1 x 10(-4) M amitriptyline. Significant LDH release did not occur until 8 h after treatment with this intermediate concentration. Even though there was no significant LDH release at all 3 time points tested, there was a 50% decrease in beating activity (154 +/- 9 to 77 +/- 5 beats/min) and initiation of vacuole formation by 2 h with the lowest concentration of amitriptyline (1 x 10(-5) M). This study presents a new apparatus for the isolation of adult cardiac myocytes for the establishment of primary cell cultures for toxicologic testing. Furthermore, these data demonstrate that amitriptyline induces a concentration- and time-dependent cardiotoxic profile in a model of spontaneously contracting adult cardiac muscle cells in culture.

Amitriptyline

Effects of maternal calorie-restricted diet on development of the foetal heart, as evaluated in primary cultures of rat myocardial cells.

Very-low-calorie diets have been implicated in causing ventricular arrhythmias and sudden cardiac death. Furthermore, studies indicate that maternal carbohydrate-restricted diets consumed during pregnancy and lactation reduce foetal growth, parturition and postnatal survival of rat pups. In this study, Sprague-Dawley rats were maintained on a semi-purified full-calorie or 50% carbohydrate-calorie-restricted diet throughout pregnancy. The function and integrity of myocardial cell cultures obtained from 3-5-day-old offspring from both groups of dams were evaluated after a drug-induced toxic challenge. After the myocytes had been in culture for 4 days, they were exposed to various concentrations of amitriptyline (1 x 10(-3) to 1 x 10(-5) M). Morphology, beating activity, lactate dehydrogenase release, glucose utilization, beta-adrenergic receptor [125I]iodopindolol binding, and cellular adenosine triphosphate content were evaluated for 24 hr after drug exposure. There were no significant differences in morphology, beating activity or glucose utilization between the full-calorie and calorie-restricted groups. When compared with the full-calorie group, lactate dehydrogenase release from the calorie-restricted group was significantly lower at 8 hr for the untreated controls and those cells exposed to 1 x 10(-4) and 1 x 10(-5) M-amitriptyline. Adenosine triphosphate levels were lower in untreated controls from the calorie-restricted group when compared with the full-calorie group at 4 hr. Within the calorie-restricted group, those cultures exposed to 1 x 10(-4) M-amitriptyline had significantly depressed adenosine triphosphate levels after 8 hr of drug treatment when compared with their respective untreated controls. Finally, the calorie-restricted group had significantly increased binding affinities of beta-receptors. Thus, maternal consumption of calorie-restricted diets during pregnancy may affect the myocardial functional capacity and integrity of the offspring.

Adenosine Triphosphate

New aniline blue dye medium for rapid identification and isolation of Candida albicans.

Organic dyes have long been used in diagnostic microbiology to differentiate species by color reactions. We studied the ability of a new noninhibitory medium, YM agar containing 0.01% aniline blue WS dye, Colour Index 42780 (YMAB), to identify Candida albicans among 1,554 yeast specimens obtained from seven clinical laboratories. Appropriate American Type Culture Collection and other characterized strains served as controls. A total of 487 of the clinical strains were identified as C. albicans. The remainder were other Candida species and non-Candida yeasts. Clinical isolates and controls were grown on Sabouraud agar for 18 h at 30 degrees C and then transferred to YMAB. Plates were incubated for 12 to 18 h at 30 degrees C, and colonies were observed for yellow-green fluorescence under long-wave UV light (A365). All control strains of C. albicans and Candida stellatoidea fluoresced, as did 480 of the 490 isolates designated as C. albicans (which included 3 strains of C. stellatoidea). Cells of C. albicans grown on YMAB produced germ tubes in serum. Only five of the other 1,062 non-C. albicans yeasts fluoresced. The sensitivity and specificity were 98.0 and 99.5%, respectively, with a predictive value of 99.1%. A fluorescent metabolite was found in cell wall particulate fractions of C. albicans sonic extracts grown on YMAB but not in non-C. albicans yeasts. This metabolite showed the same spectral curve as those of metabolites from whole cells in a recording spectrofluorometer when it was excited at 400 nm and scanned from 420 to 550 nm. Thus, growth on YMAB generates the production of a fluorescent moiety that can be used to specifically identify C. albicans within 12 to 18 h.

Aniline Compounds

Changes in intracranial CSF volume after lumbar puncture and their relationship to post-LP headache.

Post-lumbar puncture (LP) headache may be due to "low CSF pressure", leading to stretching of pain sensitive intracranial structures. The low intracranial pressure is secondary to net loss of intracranial CSF. It has, however, not been possible to measure intracranial CSF volume accurately during life until recently. Intracranial CSF volume can now be measured non-invasively by a MRI technique. The changes in intracranial CSF volume were studied in 20 patients who had LP. Total intracranial CSF volume was reduced in 19 of the 20 patients 24 hours after LP (range -1.8 mls to -158.6 mls). Most of the CSF was lost from the cortical sulci. Very large reductions in intracranial CSF volume were frequently related to post-LP headache but some patients developed headache with relatively little alteration in the intracranial CSF volume. There was not a measurable change in position of the intracranial structures following LP.

Adolescent

Severe amnesia after hypoglycemia. Clinical, psychometric, and magnetic resonance imaging correlations.

OBJECTIVE: To determine the correlation between clinical, psychometric, and magnetic resonance imaging (MRI) findings after an episode of hypoglycemic coma resulting in amnesia. RESEARCH DESIGN AND METHODS: Detailed psychometric assessment, especially memory testing, performed with MRI in a man with severe amnesia after hypoglycemic coma. RESULTS: Psychometric testing confirmed impaired immediate recall. MRI findings were consistent with a lesion in the left temporal lobe. CONCLUSIONS: This is the first description of MRI in determining the neurological damage in hypoglycemic coma.

Adult

Metastatic epidural spinal cord compression.

It is important to remember that ESCC is a complication of systemic malignancy and usually denotes disseminated disease with poor survival rates. Early diagnosis is crucial. The initial symptom is almost always back pain, which is local, radicular, or both. Following neurologic examination and radiography, MRI scanning or myelography/CT is immediately indicated if radiculopathy or myelopathy is present or if the radiographs of the spine are abnormal. In cancer patients with local back pain and normal findings on neurologic examination and radiography of the spine, there is still a probability of 0.1 of significant ESCC. Therefore, urgent CT/MRI scanning is justified. At present, the best treatment for ESCC remains unknown. In the majority of patients, radiotherapy is the most readily available and appropriate option because it is equal in effect to posterior decompressive laminectomy in both radiosensitive and radioresistant tumors. In patients with posterior epidural disease without tissue diagnosis, laminectomy with or without stabilization should be performed. Posterior decompressive laminectomy alone is contraindicated in patients with vertebral collapse. In selected instances of anterior epidural compression without tissue diagnosis or after failure of radiotherapy, an anterior surgical approach or synchronous vertebral decompression with posterior stabilization may be indicated. In the future, after appropriate clinical trials, vertebral body resection may be the optimal approach in de novo selected patients with ESCC with radioresistant tumors and limited systemic spread of the disease.

Combined Modality Therapy