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Biomedical subjects

J E Simon

Publications and source records attributed to J E Simon.

At least 19 recordsLinked to original sources
PubMed2005

Silent ischemia in minor stroke and TIA patients identified on MR imaging.

BACKGROUND: In a general population of patients with stroke, the rate of new MRI lesions at 1 week was much higher than expected. With patients with minor stroke and TIA having a higher risk of recurrent clinical events, the authors examined whether patients with minor stroke and TIA also had a high rate of asymptomatic lesions on repeat MRI scanning. METHODS: Patients with minor stroke and TIA presenting within 12 hours of symptom onset with a NIH Stroke Scale score less than six, who had a baseline MRI and a 1-month follow-up, were enrolled in this study. The follow-up study was examined for new diffusion-weighted imaging lesions as compared to the baseline study. Clinical or MRI factors predicting recurrent lesions were examined. RESULTS: A total of 143 patients were enrolled and 14 patients (9.8%; 95% CI 5.4, 15.9) had MR evidence of new lesions at 30 days. Six of these new lesions were clinically asymptomatic (42.9%; 95% CI 17.7, 71.1). A trend to increased likelihood of new lesions at 30 days was seen with progressing baseline scan lesion number (none [2.2%], solitary [12.9%], multiple [19.8%]: p = 0.046). Patients whose mechanism of stroke was large artery or cardioembolic were the most likely to have new lesions on follow-up MRI. CONCLUSION: Minor stroke and TIA are associated with a 10% risk of new lesions on MRI and half of these new lesions are asymptomatic. This risk is lower than seen in more severely affected patients with stroke. Patients with multiple lesions at baseline are at an increased risk for new ischemic lesions.

Aged↗
PubMed2004

In vivo and in vitro activities of the seed extract of Piper guineense Schum. and Thonn. against skin and gill monogenean parasites of gold fish (Carassius auratus auratus).

Methanol extracts of the seeds of Piper guineense (Piperaceae) were active against gold fish (Carassius auratus auratus L. Pisces Cyprinidae) monogenean parasites. The seed extract of P. guineense was administered at different concentrations (0.5-2.0 mg/L) under in vivo and in vitro conditions. There was a higher efficacy of the effects of the extracts against fish parasites under in vitro situations than under in vivo. Three major compounds (piperanine, N-isobutyl (E,E)-2,4 decadienamide and Deltaalpha,beta-dihydrowasanine) were identified from the seed extract of Piper guineense by LC-MS analysis.

Animals↗
PubMed2003

CT assessment of conjugate eye deviation in acute stroke.

Conjugate eye deviation seen on clinical examination helps to localize pathology in acute ischemic stroke. Eye deviation can also be assessed on a CT head scan. The authors found that CT eye deviation reliably lateralizes to the ischemic hemisphere (positive predictive value 93%) without reference to clinical examination. In an era of thrombolysis and rapid decision making in acute ischemic stroke, eye deviation on CT can help quickly direct attention to the affected hemisphere.

Acute Disease↗
PubMed2001

An investigation of the storage and biosynthesis of phenylpropenes in sweet basil.

Plants that contain high concentrations of the defense compounds of the phenylpropene class (eugenol, chavicol, and their derivatives) have been recognized since antiquity as important spices for human consumption (e.g. cloves) and have high economic value. Our understanding of the biosynthetic pathway that produces these compounds in the plant, however, has remained incomplete. Several lines of basil (Ocimum basilicum) produce volatile oils that contain essentially only one or two specific phenylpropene compounds. Like other members of the Lamiaceae, basil leaves possess on their surface two types of glandular trichomes, termed peltate and capitate glands. We demonstrate here that the volatile oil constituents eugenol and methylchavicol accumulate, respectively, in the peltate glands of basil lines SW (which produces essentially only eugenol) and EMX-1 (which produces essentially only methylchavicol). Assays for putative enzymes in the biosynthetic pathway leading to these phenylpropenes localized many of the corresponding enzyme activities almost exclusively to the peltate glands in leaves actively producing volatile oil. An analysis of an expressed sequence tag database from leaf peltate glands revealed that known genes for the phenylpropanoid pathway are expressed at very high levels in these structures, accounting for 13% of the total expressed sequence tags. An additional 14% of cDNAs encoded enzymes for the biosynthesis of S-adenosyl-methionine, an important substrate in the synthesis of many phenylpropenes. Thus, the peltate glands of basil appear to be highly specialized structures for the synthesis and storage of phenylpropenes, and serve as an excellent model system to study phenylpropene biosynthesis.

Alkenes↗
PubMed2000

Intra-specific variability of feverfew: correlations between parthenolide, morphological traits and seed origin.

Parthenolide, a biologically active sesquiterpene lactone found in feverfew [Tanacetum parthenium (L.) Schultz Bip., Asteraceae], has been indirectly linked to the anti-migraine action of feverfew preparations. Commercial preparations of feverfew leaves are known to vary widely in parthenolide content. Thirty-one feverfew accessions of diverse origin were examined for morphological traits and parthenolide content. Significant variation in parthenolide content was found among the populations. Mean parthenolide levels ranged from non-detectable to 1.68% +/- 0.97 (per dry weight) based upon HPLC-UV-MS. In general, feverfew plants grown from wild-collected seed from botanical gardens and the USDA accessions had higher mean parthenolide levels (0.72% +/- 0.57) than plants from commercial sources, including the generic material (0.34% +/- 0.23) and cultivars (0.35% +/- 0.40). Feverfew varieties with a light green/yellow leaf color had significantly higher mean parthenolide levels (1.61% +/- 0.61%) than darker-leafed varieties. A significant positive correlation between days to anthesis and parthenolide content was observed. Parthenolide levels did not correlate with floral morphology. This study shows that further selection for improved horticultural attributes and natural product content has potential to improve feverfew for the botanical/medicinal plant industry.

Plants, Medicinal↗
PubMed1996

Rules and regulations on the collection in Cameroon of biological materials for biological testing and drug discovery.

Regulations on the exploitation of Cameroon's rich biodiversity have tended to emphasize timber exploitation at the expense of non-timber uses. Materials for scientific research have been marginalized. However, in-service instructions usually provide practical guidelines such as specific charges that researchers must pay for the collection of samples. Even though the current law and text of application are silent on regulations addressing the scientific "prospecting' or exploitation of the forests, it is hoped that a particular text in conformity with the current regulations will provide more specific rules governing the collection, testing and exportation of biological materials for drug testing and discovery.

Animals↗
PubMed1994

Use of magnetization transfer for improved contrast on gradient-echo MR images of the cervical spine.

PURPOSE: To evaluate whether magnetization transfer (MT) can improve image contrast on gradient-recalled echo (GRE) magnetic resonance (MR) images of the cervical spine. MATERIALS AND METHODS: Sagittal and axial two-dimensional conventional GRE and MT GRE images were obtained in 103 patients with degenerative disk disease or intrinsic cord lesions. The contrast-to-noise ratios (C/Ns) for the cervical spinal cord and cerebrospinal fluid (CSF) were compared for images obtained at various MT power level and section-select flip angle combinations. Axial three-dimensional GRE images were also obtained with application of MT and C/N evaluated in 10 additional patients. RESULTS: Tailored two-dimensional MT GRE images, obtained with a moderate MT power level and a section-select flip angle similar to the Ernst angle for CSF, provided an average of 2.2-2.4-fold improvement in spinal cord-CSF C/N than conventional GRE images (P < .001). CONCLUSION: The MT GRE images demonstrated superior delineation of disk herniations, foraminal stenosis, and intrinsic cord lesions over conventional GRE and T2-weighted spin-echo images in clinical cervical spine examinations.

Cervical Vertebrae↗
PubMed1992

Thalamic amnesia: Korsakoff syndrome due to left thalamic infarction.

In order to support the concept that a lesion of the thalamus is sufficient to cause a Korsakoff syndrome, we are presenting 5 patients, all of whom developed the syndrome after sustaining a left (dominant) thalamic infarction. Two patients had pure thalamic strokes followed by a permanent Korsakoff syndrome. One of these patients was studied with neuropsychometric testing, as well as with a modern MRI scan. In 2 other patients, clinical and imaging data indicate that infarction was not limited to the thalamus. Another patient had bilateral thalamic infarcts but only a temporary Korsakoff syndrome. Neuropathological data are needed to elucidate the exact anatomical substrate of dominant thalamic Korsakoff syndrome.

Aged↗
PubMed1992

Racemic epinephrine use in croup and disposition.

The purpose of this study was to determine the effectiveness of a protocol for the outpatient management of laryngotracheitis (croup) using racemic epinephrine and steroids. The authors retrospectively reviewed fifty consecutive charts of children with croup who were treated under this protocol in the Scottish Rite Children's Medical Center Emergency Department (Atlanta, GA) and discharged to home after 2 hours of observation. Forty-seven of the 50 children had stridor at rest and/or retracting at rest on presentation to the emergency department. Forty-seven of the 50 patients did not require further medical care within 48 hours. One patient required another emergency visit and additional treatment with racemic epinephrine. Two patients were lost to follow-up. This study suggests that selected children presenting with croup and significant distress may be effectively treated with racemic epinephrine and steroids, observed for at least 2 hours, and safely discharged home.

Aerosols↗
PubMed1992

Computerized diagnostic referencing in pediatric emergency medicine.

A well-qualified and dedicated pediatrician in a mid-Atlantic state recently cared for a 4-year-old child with a fever and a truncal rash. On the second visit the child was lethargic but seemed to improve with oral hydration and fever control. Twenty hours later the child's rash became petechial and the child returned moribund and died shortly thereafter. Looking for an emergency differential diagnosis on a 4-year-old child with fever and a truncal rash would have been cumbersome using traditional reference materials. With PEM-DXP, however, a nurse or secretary could have produced for the physician in 60 seconds a list of 12 emergency diagnoses to be considered. Rocky Mountain spotted fever would have appeared on that list. (Ten percent of patients with Rocky Mountain spotted fever have a maculopapular rash, and in 10% of those children the rash begins on the trunk.) This list might have prompted this physician to ask about a tick bite. A positive response would have been obtained. Possibly the tragic outcome, for both the child and the physician, could have been avoided. Children with urgent complaints are frequently cared for by physicians who are busy, tired, sleep-deprived, and stressed in many other ways. These physicians often have not read last month's medical journals in their specialty or even last year's journals. Yet the parents' expectation, and rightly so, is that their pediatrician or emergency physician has at his or her command and is bringing to bear on the care of their child the vast knowledge base of medical science as it pertains to their child's condition. It is a totally unrealistic expectation. By computerizing reference materials in ways that allow for selectively searching for and compiling information pertinent to a given presentation, however, we can move a bit closer to meeting both the parents' expectations of us and our own expectations of ourselves.

Child↗
PubMed1990

Site of action for endotoxin-induced cortisol release in the suppression of preovulatory luteinizing hormone surges.

The study was conducted to identify the mechanisms of endotoxin/cortisol action in the suppression of preovulatory LH surges in heifers infused with Escherichia coli (E. coli ) endotoxin. The hypotheses tested were that 1) endotoxin stimulates the release of progesterone, possibly from the adrenal leading to the LH blockade; 2) cortisol released in response to endotoxin infusion blocks the synthesis of estradiol at the ovarian level, culminating in a failure of the LH surge. Eight Holstein heifers were given two injections of prostaglandin F(2alpha) (PG), 11 d apart, to synchronize estrus. Starting from 25 h after the second injection of PG (PG-2), the uterus of each heifer was infused either with 5 ml of pyrogen-free water (control, n = 3) or with E. coli endotoxin (5 mug/kg of body weight) in 5 ml of pyrogen-free water (treated, n = 5), once every 6 h for 10 treatments. Blood samples were obtained every 15 min for 1 h before infusion and again 2 h after each infusion, then hourly until 1 h before the next infusion. After the tenth infusion, blood was collected daily until estrus. Serum progesterone concentrations remained at baseline values (< 1 ng/ml) in control and treated heifers. The total amount of progesterone measured starting 24 to 84 h after PG-2 injection was not different between control and treated heifers (P 0.05). In the control heifers, serum estradiol concentrations remained basal (< 10 pg/ml) until 4 h before the LH surge. Serum estradiol concentrations increased to 20 +/- 5.6 pg/ml, 4 h before the LH surge in control heifers (LH surge occurred 60 to 66 h after the PG-2 injection). There were no changes in serum estradiol concentrations in treated heifers during the sampling period, and the concentrations remained < 10 pg/ml. The total amount of estradiol measured in control heifers was higher (P < 0.05) than in treated heifers. The results if this study suggest that increases in cortisol concentrations after the infusion of endotoxin might block the synthesis of estradiol at the ovarian level, resulting in the failure of a preovulatory LH surge to occur.

Journal Article↗
PubMed1988

Effects of air quality on foliar injury, growth, yield, and quality of muskmelon.

An evaluation of the effects of ambient ozone (O3) on muskmelon was conducted with the use of open-top chambers (OTCs). 'Superstar' muskmelons grown in charcoal-filtered (CF) chambers compared to those grown in nonfiltered (NF) chambers showed significant differences in the severity of visible foliar O3 injury. Furthermore, plants grown in NF conditions had significantly less (21.3%) marketable fruit weight and fewer (20.9%) marketable fruit number than those from CF chambers. No differences were found in early biomass production, leaf area, or number of nodes after 3 weeks of exposure to treatment conditions. Ambient O3 did not affect soluble solids content of mature fresh fruit nor foliage fresh weight at final harvest. Results indicate that ambient concentrations of O3 in southwestern Indiana caused significant foliar injury and yield loss to muskmelons.

Journal Article↗
PubMed1988

Tongue in cheek? Or in the bottle?

The case of an eight-year-old girl whose tongue became entrapped in a bottle is presented. Management options are discussed. Successful management utilizing a positive pressure technique is described and illustrated.

Child↗