Biomedical subjects

S Vogel

Publications and source records attributed to S Vogel.

At least 37 records · Page 2Linked to original sources

PubMed2000

Diversity of mouse lipoxygenases: identification of a subfamily of epidermal isozymes exhibiting a differentiation-dependent mRNA expression pattern.

By using reverse transcription-polymerase chain reaction technology (RT-PCR) and Northern blot analysis, the tissue-specific mRNA expression patterns of seven mouse lipoxygenases (LOX)--including 5S-, 8S-, three isoforms of 12S-, 12R-LOX, and a LOX of an as-of-yet unknown specificity, epidermis-type LOX-3 (e-LOX-3)--were investigated in NMRI mice. Among the various tissues tested epidermis and forestomach were found to express the broadest spectrum of LOX. With the exception of 5S- and platelet-type 12S-LOX (p12S-LOX) the remaining LOX showed a preference to exclusive expression in stratifying epithelia of the mouse, in particular the integumental epidermis. The expression of the individual LOX in mouse epidermis was found to depend on the state of terminal differentiation of the keratinocytes. mRNA of epidermis-type 12S-LOX (e12S-LOX) was detected in all layers of neonatal and adult NMRI mouse skin, whereas expression of p12S-LOX, 12R-LOX, and e-LOX-3 was restricted to suprabasal epidermal layers of neonatal and adult mice. 8S-LOX mRNA showed a body-site-dependent expression in that it was detected in stratifying epithelia of footsole and forestomach but not in back skin epidermis. In the latter, 8S-LOX mRNA was strongly induced upon treatment with phorbol esters. With the exception of e12S-LOX and p12S-LOX, the isozymes that are preferentially expressed in stratifying epithelia are structurally related and may be grouped together into a distinct subgroup of epidermis-type LOX.

Aging↗

PubMed2000

Dietary cholesterol increases the susceptibility of low density lipoprotein to oxidative modification.

Evidence suggests that oxidative modification of low density lipoprotein (LDL) occurs in vivo, increasing the atherogenecity of the particle. A total of 13 subjects (age range 46-78 years) with an LDL cholesterol concentration >3.36 mmol/l consumed each of four diets for 32-day periods. The diets contained 30% energy as fat of which 2/3 was either corn oil or beef tallow with and without 115 mg/4.2 MJ of supplemental cholesterol in the form of cooked egg yolk. The susceptibility of LDL to oxidation was assessed during a challenge with hemin and hydrogen peroxide, and results are expressed as lag time to oxidation in minutes. Addition of moderate amounts of cholesterol to either the corn oil or beef tallow enriched diet resulted in increased susceptibility of LDL to oxidation (decreased lag time): 69+/-22 min versus 96+/-24 min in the corn oil diet with versus without supplemental cholesterol, respectively, P = 0.006; 82+/-20 min versus 96+/-26 min in the beef tallow diet with versus without supplemental cholesterol, respectively, P = 0.025. A stepwise equation indicated that as plasma oleic acid concentrations increased and/or linoleic acid concentrations decreased, lag time increased (decreased susceptibility to oxidation), whereas as dietary cholesterol concentrations increased, lag time decreased (increased susceptibility to oxidation). In conclusion, these data suggest that addition of a moderate amount of dietary cholesterol to a reduced fat diet rich in polyunsaturated or saturated fatty acids increased the in vitro susceptibility of LDL to oxidation.

Aged↗

PubMed2000

Pulmonary sequestration presenting as a prenatally detected suprarenal lesion in a neonate.

An echogenic suprarenal mass was detected antenatally in the fetus by routine ultrasound scan. Resection of the mass after delivery confirmed an extralobar pulmonary sequestration with features of a type II congenital cystic adenomatoid malformation of the lung. The lesion should be considered in all neonates presenting with a suprarenal or upper abdominal mass particularly when the mass has been detected antenatally. Ultrasound-guided needle biopsy if feasible could provide a reasonably confident diagnosis. Congenital anomalies in other organs should be looked for carefully.

Abdominal Neoplasms↗

PubMed2000

Patients' satisfaction with osteopathic and GP management of low back pain in the same surgery.

Chronic low back patients reported their satisfaction with the treatment they received for back pain from GPs and osteopaths practising in the same surgery. Although levels of satisfaction were high for all treatments, patients reported significantly higher scores for satisfaction with the osteopathic treatment. The difference was stronger for aspects of care/communication and competence, and weaker for satisfaction with efficacy. These findings are discussed in reference to patients' expectations, novelty, time spent with patients, number of visits, and patients' age.

Adult↗

PubMed2000

Combination therapy with amprenavir, abacavir, and efavirenz in human immunodeficiency virus (HIV)-infected patients failing a protease-inhibitor regimen: pharmacokinetic drug interactions and antiviral activity.

Patients with plasma viral RNA >50,000 copies/mL, despite a protease-inhibitor regimen, received abacavir, amprenavir, and efavirenz to assess efavirenz-amprenavir drug interactions and to evaluate safety and antiviral response. Patients first received amprenavir with abacavir and other nucleoside analogs. Amprenavir levels were measured before and after adding efavirenz. Patients then received a second protease inhibitor. There was evidence of genotypic and phenotypic resistance at study entry. No patient had study drugs discontinued because of toxicity. Efavirenz decreased the steady-state area under the curve, maximum plasma concentration, and minimum plasma concentration of amprenavir by 24%, 33%, and 43%, respectively. Three of 10 patients had >1.5 log10 viral response to abacavir and amprenavir. All 8 patients who added efavirenz had >0.5 log10 decline in viral load, and this response lasted >24 weeks for 3 of the patients. A combination regimen that included abacavir, amprenavir, and efavirenz was well tolerated and had sustained activity in some patients. Concomitant efavirenz therapy decreases amprenavir concentrations.

Adult↗

PubMed2000

Retinol and retinol-binding protein: gut integrity and circulating immunoglobulins.

Vitamin A (retinol) is required to maintain immunity and epithelial turnover and is a key micronutrient needed for combating infection. Vitamin A actions on the immune system are diverse and cannot be accounted for by a single effect or mechanism. The actions of retinol in maintaining gut integrity in humans and immunoglobulin levels in mice was investigated. For 30 children, performance on the lactulose/mannitol test, a test commonly used to assess intestinal barrier function, was inversely correlated (P=.012) with serum retinol concentrations. Thus, children with lower serum retinol, and presumably poorer vitamin A nutritional status, are more likely to have impaired intestinal integrity. Knockout mice that have impairments in plasma retinol transport have circulating immunoglobulin levels that are half those observed in matched wild type mice. No differences were observed in B and T cell populations present in spleen, thymus, and bone marrow.

Animals↗

PubMed2000

Augmented sympathetic response to bradykinin in the diabetic heart before autonomic denervation.

We studied whether diabetes mellitus affects the bradykinin (BK)-induced release of norepinephrine (NE) from rat cardiac sympathetic endings in situ. Three groups were studied. Group A (n=12) was rendered diabetic with streptozotocin (STZ), group B (n=13) received STZ and insulin, and group C (n=14) received citrate buffer only. NPH insulin was given to group B from day 7 after STZ. Atria were paced (3Hz) with rectangular voltage pulses at mechanical threshold intensity (0.15 V/cm). The release of NE was assessed through its effects on contractile force in the presence of atropine (1 micromol/L). Intensifying the field stimulation above the neural threshold ( approximately 0.4 V/cm) produced a graded positive inotropic effect that was due to the release of NE from sympathetic nerve endings. The additional effect of 0.1 micromol/L BK on the force of contraction was determined at half-maximal neural stimulation (ie, at approximately 0.65 V/cm). Then, after washing out BK and lowering the stimulation intensity to mechanical threshold, a cumulative dose-response curve for added NE was generated, allowing the positive inotropic effects of neural stimulation (with or without BK) to be expressed in terms of an equivalent inotropic concentration of added NE ([NE(eq)]). Neural stimulation, in the absence of BK, gave an [NE(eq)] of 32+/-3 nmol/L in group A, 44+/-6 nmol/L in group B, and 37+/-6 nmol/L in group C. BK increased [NE(eq)] by a factor of 6.2+/-0.9 in group A, 4.5+/-0.5 in group B, and 3.7+/-0.3 in group C. This factor was greater in group A than in group C but indistinguishable in groups B and C. Atria from normal and diabetic rats were incubated in (3)[H]NE for 60 minutes. Excess tracer was removed, and atria were stimulated during a series of 1-minute episodes at half-maximal neural stimulation to cause exocytotic (3)[H]NE release. BK augmented (3)[H]NE release in normal (n=4) and in diabetic (n=4) atria. This BK-induced increase of (3)[H]NE overflow (expressed as a fraction of tissue (3)[H]NE radioactivity) was 4 times greater in diabetic than in normal preparations. The response to BK in releasing sympathetic neurotransmitter is augmented in diabetic rats, recovering in a manner dependent on insulin.

Animals↗

PubMed2000

Reorientation of daffodil(Narcissus: Amaryllidaceae) flowers inwind: drag reduction andtorsional flexibility.

Daffodil flowers extend laterally from the long axes of their stems; as a result, wind on a flower exerts torsional as well as flexural stress on the stem. Stems respond by twisting, and thus flowers reorient to face downwind in moderate winds, in the process reducing their drag by ∼30%. This repositioning is facilitated by the stems' relatively low torsional stiffness. Daffodil stems have a ratio of flexural to torsional stiffness of 13.27 ± 0.96 (SD), compared with 8.33 ± 3.20 (SD) for tulip stems, which bear flowers as symmetrical extensions of their long axes, and compared with 1.5 for isotropic, incompressible, circular cylinders.

Journal Article↗

PubMed2000

Communication between general and manipulative practitioners: a survey.

A survey of general practitioners (GPs) in the south of England was undertaken to determine their understanding and communication needs in referring patients to practitioners of manipulation. Eighty-six out of 309 GPs replied to a postal questionnaire (28% response). The results suggest that, while routine communication is important for improving understanding, GPs appear to have a preference for disciplines of which they have personal experience. The majority of responders favoured receiving a report on one side of A5 paper when the patient completes treatment. This should contain the nature of treatment and advice given and an indication of its outcome. Those who desired an initial report wanted it to contain a summary of the nature of the problem, a brief history, a summary of relevant findings from the examination, any investigations and a prognosis. Many GPs commented that they were more comfortable in referring to physiotherapists because they felt they had a better understanding of the treatment involved. Furthermore, chiropractic and osteopathic terminologies were reported to be confusing more often than physiotherapy terminology. Bearing in mind the potential bias in responses due to its geographical limitations and low response rate, this study provides useful indicators for manipulative and GPs who wish to work more closely together.

Adult↗

PubMed2000

An immortalized rat liver stellate cell line (HSC-T6): a new cell model for the study of retinoid metabolism in vitro.

Hepatocytes and hepatic stellate cells play important roles in retinoid storage and metabolism. Hepatocytes process postprandial retinyl esters and are responsible for secretion of retinol bound to retinol-binding protein (RBP) to maintain plasma retinol levels. Stellate cells are the body's major cellular storage sites for retinoid. We have characterized and utilized an immortalized rat stellate cell line, HSC-T6 cells, to facilitate study of the cellular aspects of hepatic retinoid processing. For comparison, we also carried out parallel studies in Hepa-1 hepatocytes. Like activated primary stellate cells, HSC-T6 express myogenic and neural crest cytoskeletal filaments. HSC-T6 cells take up and esterify retinol in a time- and concentration-dependent manner. Supplementation of HSC-T6 culture medium with free fatty acids (up to 300 micrometer) does not affect retinol uptake but does enhance retinol esterification up to 10-fold. RT-PCR analysis indicates that HSC-T6 cells express all 6 retinoid nuclear receptors (RARalpha, -beta, -gamma, and RXRalpha, -beta, -gamma) and like primary stellate cells, HSC-T6 stellate cells express cellular retinol-binding protein, type I (CRBP) but fail to express either retinol-binding protein (RBP) or transthyretin (TTR). Addition of retinol (10(-8)-10(-5) m) or all-trans-retinoic acid (10(-10)-10(-6) m) rapidly up-regulates CRBP expression. Using RAR-specific agonists and antagonists and an RXR-specific agonist, we show that members of the RAR-receptor family modulate HSC-T6 CRBP expression.Thus, HSC-T6 cells display the same retinoid-related phenotype as primary stellate cells in culture and will be a useful tool for study of hepatic retinoid storage and metabolism.

Animals↗

PubMed2000

Benefits of early utilization of intravenous iron.

Better anemia management has dramatically improved the lives of many patients with end stage renal disease (ESRD). Nephrology professionals frequently use two tools--erythropoietin and supplemental iron--to manage anemia. The National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF-DOQI) suggests that most ESRD patients will need intravenous (i.v.) iron to optimize their response to erythropoietin. In this report, the author reviews published studies showing that i.v. iron reduces erythropoietin dose requirements, resulting in cost savings. She presents data from her center illustrating that i.v. administration of the newly approved Ferrlecit (sodium ferric gluconate) also improves anemia management and reduces erythropoietin dose requirements. The author reviews studies showing the efficacy of i.v. iron as monotherapy for anemia in ESRD patients. These data support the importance of i.v. iron as an agent to be used alone or in conjunction with erythropoietin in the management of anemia in patients with ESRD.

Adult↗

PubMed2000

Rhino horns and paper cups: deceptive similarities between natural and human designs.

One cannot assume that resemblances between the mechanical devices of human technology and those produced by the evolutionary process reflect either specific copying of nature by people or some particular point of functional superiority. A third alternative is that the two mechanical contexts derive quite different advantages from a given arrangement. While this latter might appear unlikely, one can argue that it underlies such things as the use of conical shapes, helical tensile structures, spheres and cylinders, beams and columns of relatively low torsional stiffness, and geodesic shells.

Animals↗

PubMed1999

Impaired retinal function and vitamin A availability in mice lacking retinol-binding protein.

Retinol-binding protein (RBP) is the sole specific transport protein for retinol (vitamin A) in the circulation, and its single known function is to deliver retinol to tissues. Within tissues, retinol is activated to retinoic acid, which binds to nuclear receptors to regulate transcription of >300 diverse target genes. In the eye, retinol is also activated to 11-cis-retinal, the visual chromophore. We generated RBP knockout mice (RBP(-/-)) by gene targeting. These mice have several phenotypes. Although viable and fertile, they have reduced blood retinol levels and markedly impaired retinal function during the first months of life. The impairment is not due to developmental retinal defect. Given a vitamin A-sufficient diet, the RBP(-/-) mice acquire normal vision by 5 months of age even though blood retinol levels remain low. Deprived of dietary vitamin A, vision remains abnormal and blood retinol declines to undetectable levels. Another striking phenotype of the mutant mice is their abnormal retinol metabolism. The RBP(-/-) mice can acquire hepatic retinol stores, but these cannot be mobilized. Thus, their vitamin A status is extremely tenuous and dependent on a regular vitamin A intake. Unlike wild-type mice, serum retinol levels in adult RBP(-/-) animals become undetectable after only a week on a vitamin A-deficient diet and their retinal function rapidly deteriorates. Thus RBP is needed for normal vision in young animals and for retinol mobilization in times of insufficient dietary intake, but is otherwise dispensable for the delivery of retinol to tissues.

Age Factors↗

PubMed1999

Carboxyl ester lipase overexpression in rat hepatoma cells and CEL deficiency in mice have no impact on hepatic uptake or metabolism of chylomicron-retinyl ester.

To study the role of carboxyl ester lipase (CEL) in hepatic retinoid (vitamin A) metabolism, we investigated uptake and hydrolysis of chylomicron (CM)-retinyl esters (RE) by rat hepatoma (McArdle-RH7777) cells stably transfected with a rat CEL cDNA. We also studied tissue uptake of CM-RE in CEL-deficient mice generated by targeted disruption of the CEL gene. CEL-transfected cells secreted active enzyme into the medium. However, both control and CEL-transfected cells accumulated exogenously added CM-RE or CM remnant (CMR)-derived RE in equal amounts. Serum clearance of intravenously injected CM-RE and cholesteryl ester were not different between wild-type and CEL-deficient mice. Also, the uptake of the two compounds by the liver and other tissues did not differ. These data indicate that the lack of CEL expression does not affect the uptake of dietary CM-RE by the liver or other tissues. Moreover, the percentage of retinol formed in the liver after CM-RE uptake, the levels of retinol and retinol-binding protein in serum, and retinoid levels in various tissues did not differ, indicating that CEL deficiency does not affect hepatic retinoid metabolism and retinoid distribution throughout the body. Surprisingly, in both pancreas and liver of wild-type, heterozygous, and homozygous CEL-deficient mice, the levels of bile salt-dependent retinyl ester hydrolase (REH) activity were similar. This indicates that in the mouse pancreas and liver an REH enzyme activity, active in the presence of bile salt and distinct from CEL, is present, compatible with the results from our accompanying paper that the intestinal processing and absorption of RE were unimpaired in CEL-deficient mice.

Animals↗

PubMed1999

Evaluation of shunt function in hydrocephalic patients with the radionuclide 99mTc-pertechnetate.

In most cases of shunted hydrocephalus, shunt malfunction is evaluated by clinical examination and neuro-imaging. However if there is a discrepancy between neurological examination and imaging, additional shuntography can be helpful in the evaluation of the shunt function. In our clinic, radionuclide-imaging shuntography using (99m)technetium-pertechnetate was performed in 85 children between 1992 and 1995. The results of shuntography were evaluated visually and from time-activity curves. Shuntography had a sensitivity of 96%, a specificity of 89%, and an accuracy of 93%, proved either by surgery or by clinical follow-up for 2-5 years. Corresponding to these results, we recommend the use of shuntography in cases with an uncertain shunt function before surgical revision.

Adolescent↗

PubMed1999

Carotenoid intakes, assessed by dietary questionnaire, are associated with plasma carotenoid concentrations in an elderly population.

High intakes of fruits and vegetables and of carotenoids are associated with a lower risk for a variety of chronic diseases. It is therefore important to test the validity of dietary questionnaires that assess these intakes. We compared intakes of five carotenoids, as calculated from responses to the Willett 126-item food-frequency questionnaire, with corresponding biochemical measures. Subjects included 346 women and 201 men, aged 67-93 y, in the Framingham Heart Study. Unadjusted correlations were higher among women than men as follows: alpha-carotene 0.33 and 0.18, beta-carotene, 0.36 and 0.25; beta-cryptoxanthin, 0.44 and 0.32; lycopene, 0.35 and 0.21; and lutein + zeaxanthin, 0.27 and 0.10, respectively. Adjustment for age, energy intake, body mass index (BMI, kg/m2), plasma cholesterol concentrations and smoking reduced the gender differences, respectively, to the following: alpha-carotene 0.30 and 0.28; beta-carotene, 0.34 and 0.31; beta-cryptoxanthin, 0.45 and 0.36; lycopene, 0.36 and 0.31; and lutein + zeaxanthin, 0.24 and 0.14. Plots of adjusted mean plasma carotenoid concentration by quintile of respective carotenoid intake show apparent greater responsiveness among women, compared with men, to dietary intake of alpha- and beta-carotene and beta-cryptoxanthin, but similar blood-diet relationships for lycopene and lutein + zeaxanthin. Reported daily intake of fruits and vegetables correlated most strongly with plasma beta-cryptoxanthin and beta-carotene among women and with plasma alpha- and beta-carotene among men. With the exception of lutein + zeaxanthin, this dietary questionnaire does provide reasonable rankings of carotenoid status among elderly subjects, with the strongest correlations for beta-cryptoxanthin. Appropriate adjustment of confounders is necessary to clarify these associations among men.

Aged↗

PubMed1999

Iron management: innovative solutions to persistent challenges--focus on Ferrlecit.

The use of sodium ferric gluconate in sucrose injection (Ferrlecit) in the treatment of anemia in patients with end stage renal disease (ESRD) was the major topic at the symposium "Iron Management: Innovative Solutions to Persistent Challenges," held April 14, 1999 during the annual ANNA 30th National Symposium in Baltimore, Maryland. Chairperson Susan Vogel, MHA, RN, CNN, addressed the challenges of anemia management and the limitations of oral iron supplements. She described available intravenous (i.v.) iron therapies and reviewed clinical trial data that demonstrated an excellent safety and efficacy profile for the newly approved i.v. iron supplement, sodium ferric gluconate. Suzanne Schweitzer, RPh, MPH, discussed iron metabolism and the U.S. labeling for sodium ferric gluconate, with a focus on dosing and administration. In the final presentation, Suzanne Seiler, RN, described her clinic's experience with sodium ferric gluconate and provided an experimental dosing and monitoring protocol. Together, these presentations suggest that sodium ferric gluconate is an important new tool for meeting the challenges of iron management in ESRD patients.

Anemia, Iron-Deficiency↗

PubMed1998

Genomic difference analysis by two-dimensional DNA fingerprinting reveals typical changes in human low-grade gliomas.

Cytogenetic and molecular analyses such as allelotyping studies have revealed several genetic changes typical for human glial neoplasms. However, most studies to date have involved malignant gliomas and thus are likely to reflect late events of tumor progression. To elucidate the initial events of glial tumor growth, we performed a genome-wide search for genetic alterations in the DNA of 43 low-grade gliomas as compared to the constitutional DNA of the patients' peripheral blood leucocytes using the two-dimensional (2D) DNA fingerprint approach. Reliable results were obtained for 28 blood/tumor sample pairs (13 astrocytomas, 9 pilocytic astrocytomas, 1 oligodendroglioma, 3 oligoastrocytomas, and 2 ependymomas). DNA was digested with the restriction enzyme HaeIII and the resulting fragments were separated on 2D gels according to size and sequence in the first and second dimensions, respectively. Patterns of hundreds of spots were generated by hybridization with four different mini- and microsatellite core probes. A total of 655 to 1,122 spots could be visualized per sample. Comparison of blood and tumor spot patterns revealed two to 11 reproducible changes per patient. Most of the differences were spot losses (77.1%), while the others appeared to be gains or amplifications. Exactly the same changes were found in tumor recurrences which lacked histological signs of progression. When comparing different patients, many of the affected spots tended to cluster in particular areas of the gel as revealed by computer-aided comparison of all spot patterns. Eleven different spot clusters were identified which may correspond to several major deletion targets. This study provides the basis for the future molecular cloning of the candidate tumor suppressor genes affected by the common spot losses and will allow new insights into the genetic mechanisms of glial tumorigenesis.

Adolescent↗