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Biomedical subjects

L Rogers

Publications and source records attributed to L Rogers.

At least 19 recordsLinked to original sources
PubMed2004

Epidemiological and molecular evidence of a monophyletic infection with Staphylococcus aureus causing a purulent dermatitis in a dairy farmer and multiple cases of mastitis in his cows.

An epidemiological and molecular investigation of a cutaneous suppurative infection with Staphylococcus aureus in a dairy farmer, occurring concurrently with an outbreak of clinical mastitis in his herd, was carried out. A common aetiology for the diseases in the farmer and his cows was established by combining clinical evidence with a molecular genomic analysis of the bacterial isolates using pulsed field gel electrophoresis of DNA macro-restriction fragments. This case indicates the possibility of the emergence and circulation of anthropozoonotic clones of S. aureus in dairy herds. It also provides further evidence of the severe impact of infection with highly virulent clones on dairy lactating cattle.

Abscess↗
PubMed2002

Fatty acid analysis of wild ruminant tissues: evolutionary implications for reducing diet-related chronic disease.

HYPOTHESES: Consumption of wild ruminant fat represented the primary lipid source for pre-agricultural humans. Hence, the lipid composition of these animals' tissues may provide insight into dietary requirements that offer protection from chronic disease in modern humans. METHOD: We examined the lipid composition of muscle, brain, marrow and subcutaneous adipose tissue (AT) from 17 elk (Cervus elaphus), 15 mule deer (Odocoileus hemionus), and 17 antelope (Antilicapra americana) and contrasted them to wild African ruminants and pasture and grain-fed cattle. RESULTS: Muscle fatty acid (FA) was similar among North American species with polyunsaturated fatty acids/saturated fatty acids (P/S) values from 0.80 to 1.09 and n-6/n-3 FA from 2.32 to 2.60. Marrow FA was similar among North American species with high levels (59.3-67.0%) of monounsaturated FA; a low P/S (0.24-0.33), and an n-6/n-3 of 2.24-2.88. Brain had the lowest n-6/n-3 (1.20-1.29), the highest concentration of 22:6 n-3 (elk, 8.90%; deer, 9.62%; antelope, 9.25%) and a P/S of 0.69. AT had the lowest P/S (0.05-0.09) and n-6/n-3 (2.25-2.96). Conjugated linoleic acid (CLA) isomers were found in marrow of antelope (1.5%), elk (1.0%) and deer (1.0%), in AT (deer, 0.3%; antelope, 0.3%) in muscle (antelope, 0.4%; elk, trace), but not in brain. CONCLUSIONS: Literature comparisons showed tissue lipids of North American and African ruminants were similar to pasture-fed cattle, but dissimilar to grain-fed cattle. The lipid composition of wild ruminant tissues may serve as a model for dietary lipid recommendations in treating and preventing chronic disease.

Animals↗
PubMed2001

ALA and ALA hexyl ester-induced porphyrin synthesis in chemically induced skin tumours: the role of different vehicles on improving photosensitization.

Exogenous administration of 5-aminolevulinic acid (ALA) is becoming widely used to enhance the endogenous synthesis of Protoporphyrin IX (PpIX) in photodynamic therapy. We analysed porphyrin formation in chemically induced squamous papillomas, after topical application of ALA and ALA hexyl ester (He-ALA) administered in different formulations, as well as the pattern of distribution in the internal organs, and the synthesis of porphyrins in distant tumoural and normal skins. A lotion formulation containing DMSO and ethanol was the best vehicle for topical ALA delivery to papillomas, whereas cream was the most efficient formulation for He-ALA application. Similar porphyrin concentration can be accumulated in the skin tumours employing either ALA or He-ALA delivered in their optimal formulations. The use of cream as a vehicle of both ALA and He-ALA, induces highest porphyrin tumour/normal skin ratios. The main advantage of using He-ALA is that porphyrins synthesized from the ester are more confined to the site of application, thus inducing low porphyrin levels in normal skin, liver, blood and spleen, as well as in papillomas distant from the point of application, independently on the vehicle employed, so reducing potential side effects of photodynamic therapy.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2001

Non-coplanar inverse planning IMRT using the MIMiC system: clinical significance in choice of 2-cm/1-cm mode and single couch vs. multiple couch angles.

The IMRT delivery process using MIMiC is extremely effective. In the hands of an experienced practitioner, MIMiC can provide excellent conformity to tumor volume with minimal damage to adjacent critical structures. However, the process is not completely automatic, even though it is an inverse planning process. The choice of machine treatment mode, 1- or 2-cm mode, and the choice of single couch angle vs. multiple, will yield quite different end results, with all prescription parameters being equal. The choice of mode and number of couch angles that yield excellent results of good coverage of the PTV with minimal hot spots and appropriate degree of normal tissue sparing still depends on the clinical experience of the planner. The size, shape, and total length of the PTV and those of the organs of interest dictate the choice. The authors demonstrated some clinical examples with comparative studies of the results of different choice of these parameters. In general, smaller beamlets with multiple couch angles give better PTV conformity, and critical organ avoidance. The down side of these choices are: (a) relatively more scattered hot spots within PTV, (b) longer time required to deliver the treatment, and (c) increased complexity of the process that could increase the chance of human error in treatment delivery.

Humans↗
PubMed2001

Intrathecal treatment of neoplastic meningitis due to breast cancer with a slow-release formulation of cytarabine.

DepoCyte is a slow-release formulation of cytarabine designed for intrathecal administration. The goal of this multi-centre cohort study was to determine the safety and efficacy of DepoCyte for the intrathecal treatment of neoplastic meningitis due to breast cancer. DepoCyte 50 mg was injected once every 2 weeks for one month of induction therapy; responding patients were treated with an additional 3 months of consolidation therapy. All patients had metastatic breast cancer and a positive CSF cytology or neurologic findings characteristic of neoplastic meningitis. The median number of DepoCyte doses was 3, and 85% of patients completed the planned 1 month induction. Median follow up is currently 19 months. The primary endpoint was response, defined as conversion of the CSF cytology from positive to negative at all sites known to be positive, and the absence of neurologic progression at the time the cytologic conversion was documented. The response rate among the 43 evaluable patients was 28% (CI 95%: 14-41%); the intent-to-treat response rate was 21% (CI 95%: 12-34%). Median time to neurologic progression was 49 days (range 1-515(+)); median survival was 88 days (range 1-515(+)), and 1 year survival is projected to be 19%. The major adverse events were headache and arachnoiditis. When drug-related, these were largely of low grade, transient and reversible. Headache occurred on 11% of cycles; 90% were grade 1 or 2. Arachnoiditis occurred on 19% of cycles; 88% were grade 1 or 2. DepoCyte demonstrated activity in neoplastic meningitis due to breast cancer that is comparable to results reported with conventional intrathecal agents. However, this activity was achieved with one fourth as many intrathecal injections as typically required in conventional therapy. The every 2 week dose schedule is a major advantage for both patients and physicians.

Adult↗
PubMed2001

Using point-of-care CD34 enumeration to optimize PBSC collection conditions.

BACKGROUND: A PBSC graft containing 4-5 x 10(6) CD34(+) cells/kg is considered optimal in terms of durable engraftment. Tracking CD34 kinetics via point-of-care testing during PBSC mobilization could determine which (and when) patients will yield an optimal product. We evaluated whether microvolume fluorimetry (MVF) would be useful in optimizing PBSC mobilization/harvest and if it will shorten our standard 6 h collection. METHODS: Absolute CD34 values were obtained using the IMAGN 2000 and STELLer CD34 assay (50 microL sample volume). Peripheral blood (PB) CD34 values from 30 patients undergoing PBSC mobilization were used to generate a PB CD34-based algorithm that would predict collection day/duration of apheresis. The algorithm was then used prospectively to collect PBSC products on 50 hematologic malignancy (HM) patients. RESULTS: Using the algorithm, patients were assigned to either a 6 (11-20 CD34/microL), 4 (21-49 CD34/microL) or 2 (> or = 50 CD34/microL) h collection. Patients with a CD34 value < or = 10/microL were re-tested. All patients (n = 43) predicted to mobilize reached the optimal CD34 (4-5 x 10(6)/kg) value with 1.0 apheresis procedure; seven patients had < or = 10/microL (nonmobilizers). The majority (75%) had apheresis charges decreased by 33-66%; 47% only required a 2 h procedure and 28% required 4 h. All patients demonstrated rapid trilineage engraftment. DISCUSSION: Absolute PB CD34 measurement using MVF offers a rapid and reliable approach to obtaining optimal PBSC products with minimal technical expertise. Although not a replacement for conventional flow cytometry, it meets the requirements for a point-of-care procedure.

Algorithms↗
PubMed2001

Screening for diabetic retinopathy in rural areas: the potential of telemedicine.

Diabetic retinopathy is a common cause of blindness, and screening can identify the disease at an earlier, more treatable stage. However, rural individuals with diabetes may have limited access to needed eye care. The objective of this project was to demonstrate the feasibility of a diabetic retinopathy screening program using a state-of-the-art nonmydriatic digital fundus imaging system. The study involved a series of patients screened in primary care and public health locations throughout seven predominantly rural counties in eastern North Carolina. Images of each fundus were obtained and sent to a retinal specialist. The retinal specialist reviewed each image, recorded image quality, diagnosed eye disease and made recommendations for subsequent care. Of 193 volunteers with a history of diabetes mellitus, 96.3 percent reported that they were very comfortable or comfortable with the camera. Eighty-five percent of images were rated as good or fair by the retinal specialist. The retinal specialist also reported being very certain or certain of the diagnosis in 84 percent of cases. Image quality correlated highly with the certainty of diagnosis (Spearman's rank order correlation coefficient = 0.79; P < 0.001). The average time since the previous examination by an eye care specialist for diabetic subjects was two years. Approximately 62 percent of diabetic patients had diagnosable eye conditions, the most common of which was diabetic retinopathy (40.9 percent). In this convenience sample, African Americans, despite similar age and disease duration, were more likely to have retinopathy. Digital imaging is a feasible screening modality in rural areas, may improve access to eye care, and may improve compliance with care guidelines for individuals with diabetes mellitus.

Adult↗
PubMed2001

Social impact of same day surgery for the patient and the carer: a study of patients' experiences.

A semi-structured questionnaire was used to interview 18 patients, prior to surgery, on the day of their admission to day surgery. The purpose of the interviews was to gather information about the social arrangements, for both patient and carer, that were made necessary by the need for the patient to attend surgery and to be cared for at home over the 24-hour post-discharge period. The initial response of the patients concerning the arrangements made for their post-operative care didn't expose any far-reaching difficulties. However, their descriptive stories reveal the extent of the measures that some needed to take in order to attend surgery and be cared for at home. These results point to a need for extensive research into the cost of the social impact of day surgery on the patient and the carer.

Adolescent↗
PubMed2000

Effects of dietary conjugated linoleic acids on hepatic and muscle lipids in hybrid striped bass.

Conjugated linoleic acids (CLA) are the focus of numerous studies, yet the effects of these isomers of octadecadienoic acids have not been evaluated in many species of fish. In this study, graded amounts of CLA--0, 0.5, 0.75, or 1.0% of the diet--were fed to juvenile hybrid striped bass for 8 wk. Dietary treatments were fed to apparent satiation twice daily to triplicate groups of fish initially weighing 13.4 g/fish. Feed intake and weight gain of fish fed 1.0% CLA were significantly reduced compared to fish fed no CLA. Fish fed 0.5 and 0.75% CLA exhibited reduced feed intake similar to fish fed 1.0% CLA, but had growth rates that were not significantly different from those of fish fed no CLA. Feed efficiency improved significantly in fish as dietary CLA concentrations increased. Total liver lipid concentrations were significantly reduced in fish fed the diets containing CLA compared to those of fish fed the control diet, and intraperitoneal fat ratio was significantly lower in fish fed 1.0% CLA compared to fish fed no CLA. Fish fed dietary CLA exhibited significant increases in hepatosomatic index and moisture content of muscle and carcass. The CLA isomers were detected in liver and muscle of fish fed the diets containing CLA, while a low concentration of one isomer was detected in liver and muscle of fish fed the control diet. Dietary CLA resulted in a significant increase in 18:2(c-9,c-12) concentration in liver and muscle, but a significant reduction in 18:1n-7 in these tissues. Furthermore, feeding CLA resulted in a significant increase in the concentration of 20:5n-3 and 22:6n-3 in liver, but a reduction of these fatty acids in muscle. This study showed that feeding CLA elevated tissue concentrations of these fatty acid isomers, reduced tissue lipid contents, improved feed efficiency, and altered fatty acid concentrations in liver and muscle of fish.

Animal Nutritional Physiological Phenomena↗
PubMed2000

Effect of a lipidic extract from lepidium meyenii on sexual behavior in mice and rats.

OBJECTIVES: To determine the effect of oral administration of a purified lipidic extract from Lepidium meyenii (MacaPure M-01 and M-02) on the number of complete intromissions and mating in normal mice, and on the latent period of erection (LPE) in rats with erectile dysfunction. METHODS: Mice and rats were randomly divided into several experimental and control groups. A 10% ethanol suspension of M-01 and M-02 was orally administered for 22 days to the experimental groups according to the dosage specified by the experimental design. On day 22, 30 minutes after the dose was administered to the male mice, 2 virgin female mice were placed with 1 male mouse. The number of complete intromissions of each male mouse in 3 hours was recorded. In an assessment of 1 day of mating, each male mouse was cohabited with 5 estrous female mice overnight. The number of sperm-positive females was recorded. The LPE was measured to assess the sexual function in rats with erectile dysfunction. By using a YSD-4G multifunction instrument, an electric pulse at 20 V was applied to stimulate the rat's penis, and the duration from the start of the stimulus to full erection was measured in seconds as the LPE. RESULTS: In the normal male mice, the number of complete intromissions during the 3-hour period was 16.33 +/- 1.78, 46.67 +/- 2.39, and 67.01 +/- 2.55 for the control group, M-01 group, and M-02 group, respectively. In the assessment of mating, the number of sperm-positive females increased from 0.6 +/- 0.7 in the control group to 1.5 +/- 0.5 in the M-01 experimental group. The LPE of male rats with erectile dysfunction was 112 +/- 13 seconds with a regular diet (control group). The oral administration of M-01 at a dose of 180 or 1800 mg/kg body weight and M-02 at a dose of 45, 180, or 1800 mg/kg body weight reduced the LPE to 54 +/- 12 seconds, 54 +/- 13 seconds, 71 +/- 12 seconds, 73 +/- 12 seconds, and 41 +/- 13 seconds, respectively. The LPE of the surgical rats treated with M-01 at the lowest dose (45 mg/kg) was 121 +/- 12 seconds; thus, the change was not significant. CONCLUSIONS: Oral administration of M-01 and M-02 enhanced the sexual function of the mice and rats, as evidenced by an increase in the number of complete intromissions and the number of sperm-positive females in normal mice, and a decrease in the LPE in male rats with erectile dysfunction. The present study reveals for the first time an aphrodisiac activity of L. meyenii, an Andean Mountain herb.

Administration, Oral↗
PubMed2000

Direct analysis and identification of triterpene glycosides by LC/MS in black cohosh, Cimicifuga racemosa, and in several commercially available black cohosh products.

A method to directly identify triterpene glycosides using reversed-phase liquid chromatography with positive atmospheric pressure chemical ionization mass spectrometry (LC/(+)APCIMS) was developed. Based on the analysis of the molecular weight, fragment ions, selected ion chromatograms, a number of triterpene glycosides, including actein, 27-deoxyactein, cimicfugoside M, and cimicifugoside, from Cimicifuga racemosa were studied. A chromone, cimifugin, from C. foetida was also identified. Cimicifugoside M and cimifugin can specifically serve as indicators for species identification. The method can, therefore, be used to distinguish black cohosh products from among different plant species for quality control purposes.

Chromatography, Liquid↗
PubMed2000

Palatal distraction in a canine cleft palate model.

The purpose of this study was to determine whether the canine hard palate can be lengthened by distraction osteogenesis in a cleft palate model using a mostly submucosal distractor. Five mongrel dogs were used. After raising mucoperiosteal flaps, a midline strip of bone was removed from the hard palate of each dog to simulate the bony defect seen in a cleft palate. A transverse osteotomy was then made to separate the posterior segment of the hard palate from the anterior segment. Posterior osteotomies were also made laterally parallel to the teeth so that the 2 posterior segments (one on either side of the bony cleft) were mobile. An intraoral distractor that was mostly submucosal was attached to the anterior hard palate and both segments of the mobilized posterior hard palate. Radiopaque bone markers were placed, and x-rays were obtained. After a 10-day latency period, the distractor was expanded 0.675 mm per day until it had been lengthened 10.125 mm. Distractors were left in place for an additional 8 weeks. After distractor removal, animals were observed for an additional 8 weeks before euthanization. Follow-up x-rays and histologic examinations were performed. New bone formation was found at the site of distraction in all dogs at the time of death. This new bone was seen on the follow-up x-rays and on histologic examination of the hard palates using both hematoxylin and eosin staining and Masson's trichrome stain. Distraction osteogenesis using a mostly submucosal device is an effective technique for lengthening the hard palate in a canine cleft palate model. The technique may eventually provide an alternative treatment for velopharyngeal incompetence in humans that is more precise and involves less morbidity than existing treatments.

Animals↗
PubMed1999

Synechococcus mutants resistant to an enamine mechanism inhibitor of glutamate-1-semialdehyde aminotransferase.

An enamine mechanism-based inactivator of mammalian delta-aminobutyric acid aminotransferase, 4-amino 5-fluoropentanoic acid is a potent inhibitor of cell growth and pigment formation in the cyanobacterium Synechococcus PCC 6301. It was demonstrated that 4-amino 5-fluoropentanoic acid inhibits the aminolaevulinate synthesis at glutamate 1-semialdehyde aminotransferase and that in the mutant obtained by exposing cells to 40 microM 4-amino 5-fluoropentanoic acid, this enzyme was insensitive to the inhibitor. The specific activity of glutamate 1-semialdehyde aminotransferase in cell extracts was lower in the mutant, although the cell growth rate was unaffected. The decrease in sensitivity to 4-amino 5-fluoropentanoic acid in the mutant is due to a structural gene mutation, a single base change in the hemL gene resulting in a S162T substitution in the gene product.

Aminolevulinic Acid↗
PubMed1999

Goniotriocin and (2,4-cis- and -trans)-xylomaticinones, bioactive annonaceous acetogenins from Goniothalamus giganteus.

Goniotricin (1) and a mixture of (2,4-cis and -trans)-xylomaticinones (2), new bioactive annonaceous acetogenins, were isolated from the bark of Goniothalamus giganteus (Annonaceae) by activity-directed fractionation using the brine shrimp lethality test. Compound 1 is the first nonadjacent ring-hydroxylated bis-tetrahydrofuran (THF) acetogenin to be reported. Compound 2 is the cis- and trans-ketolactone mixture of xylomaticin, a known compound whose absolute stereochemistry has not been previously determined. The absolute stereochemistry of 2 was determined by the advanced Mosher's ester method. Both 1 and 2 showed significant and selective cytotoxicities among the six tumor cell lines in our seven-day MTT human solid tumor panel. In the yellow fever mosquito larvae microtiter assay, 1 was quite active, with an ED50 value of 3. 5 microg/mL.

Animals↗