PubMed Health⌕ Search

Biomedical subjects

R Rosenfield

Publications and source records attributed to R Rosenfield.

10 recordsLinked to original sources
PubMed2005

What is the pathogenesis of acne?

For a long time, the mantra of acne pathogenesis debates has been that acne vulgaris lesions develop when (supposedly largely androgen-mediated) increased sebum production, ductal hypercornification, and propionibacteria come together with local inflammatory process in the unlucky affected individual. And yet, the exact sequence, precise interdependence, and choreography of pathogenic events in acne, especially the 'match that lights the fire' have remained surprisingly unclear, despite the venerable tradition of acne research over the past century. However, exciting recent progress in this--conceptually long somewhat stagnant, yet clinically, psychologically, and socioeconomically highly relevant--everyday battlefield of skin pathology encourages one to critically revisit conventional concepts of acne pathogenesis. Also, this provides a good opportunity for defining more sharply key open questions and intriguing acne characteristics whose underlying biological basis has far too long remained uninvestigated, and to emphasize promising new acne research avenues off-the-beaten-track--in the hope of promoting the corresponding development of innovative strategies for acne management.

Acne Vulgaris↗
PubMed2002

Induction of puberty in the hypogonadal girl--practices and attitudes of pediatric endocrinologists in Europe.

The management of children and adolescents with hypogonadism and in particular the induction of puberty in the hypogonadal girl is subject to controversy. Therefore, under the auspices and through organization of the Drugs and Therapeutics Committee of the European Society of Paediatric Endocrinology (ESPE), an interactive voting session and workshop was held at the 39th ESPE Annual Meeting in Brussels to discuss these topics. Common practice in Europe and attitudes of pediatric endocrinologists in Europe were questioned and recorded in the 1.5-hour program. We now report on some of the results of the questionnaires and discussions of that session to further the discussion on and knowledge of current concepts of induction of puberty in the hypogonadal girl in Europe. It became clear from the data accumulated here that the start of treatment, the aims of therapy and the modalities of how to treat the hypogonadal girl vary amongst pediatric endocrinologists in Europe. For example, a chronological age > or =11 years was considered appropriate for the start of estrogen therapy by 40.4% (out of 188 answers), while 47.8 and 7.5% felt that a chronological age > or =13 and > or =15 years respectively was appropriate. In respect to the form and route of estrogen administration, the audience was asked for their common estrogen replacement practice: 31.9% used oral 17beta-estradiol treatment, while 10% would prescribe 17beta-estradiol transdermal patches. Another 12.2% would recommend conjugated estrogens (e.g. Premarin) orally, 4.8% use oral estradiol valerate and 39.3% ethinylestradiol orally. Only 1.8% out of 229 physicians answering were undecided. In addition, counseling of patients and their families is quite variable and perceptions for example regarding potential pregnancies in affected women are also not uniform. In this report the authors do not want to provide their own personal views but rather reflect current practice in Europe. It is hoped that a more uniform picture will emerge once European and international guidelines on how to treat the girl with hypogonadism will be available and even more discussions amongst doctors from different countries have been led.

Adolescent↗
PubMed1999

Significance of genetic testing for paternal uniparental disomy of chromosome 6 in neonatal diabetes mellitus.

Two patients who presented at birth with neonatal diabetes mellitus (NDM) are described: one with paternal uniparental disomy for chromosome 6 and one with normal, biparental inheritance. The first child presented with low birth weight, macroglossia, hypertelorism, and club foot in addition to NDM. In this patient hyperglycemia was transient, and insulin treatment was discontinued at 4 months of age. The second child also presented with low birth weight but was normal in appearance, and insulin dependence continues after 5 years. Genetic analysis with polymorphic DNA markers for chromosome 6 indicated the presence of paternal uniparental disomy (UPD) in the first case and normal, biparental inheritance in the second case. Paternal UPD 6 has been reported in 8 previous cases of which 6 showed NDM. Three cases with paternal UPD 6 also included additional anomalies, such as macroglossia, not usually associated with NDM. Therefore the simultaneous finding of NDM and macroglossia should be a strong indicator for genetic testing. The genetic finding of paternal UPD 6 allows prediction of a transient, rather than permanent, form of diabetes mellitus and no increased recurrence risk of transient NDM in subsequent pregnancies.

Aneuploidy↗
PubMed1997

Partial growth-hormone insensitivity: the role of growth-hormone receptor mutations in idiopathic short stature.

Mutations in the GHR locus may play a role in the cause of idiopathic short stature (ISS) by impairing growth-hormone (GH) receptor (GHR) function. At one extreme, mutations that nullify the function of the GH receptor are linked to complete GH insensitivity syndrome, or Laron syndrome, and we hypothesized that less-disruptive mutations could contribute to partial GH insensitivity syndrome. Low levels of GH binding protein may indicate mutations in the extracellular domain of the receptor, and by focusing on 14 children with ISS who had low GH binding protein and insulin-like growth factor I levels, we found three heterozygotes and one compound heterozygote for mutations in the extracellular domain of the receptor. We have since extended our study to a broader spectrum of patients, adding 76 patients with ISS who were treated with GH in a phase II study of the safety and efficacy of recombinant human GH in ISS and also adding 10 patients who were ascertained as having ISS by pediatric endocrinologists in private practice. The GHR gene has thus been analyzed in 100 patients with ISS, eight of whom were found to carry mutations: four in our original study and four with normal or elevated levels of GH binding protein. The latter group consists of three carriers of heterozygous extracellular domain mutations and one carrier of a heterozygous intracellular domain mutation. Family data suggest that the carriers of these mutations have a range of phenotypes, supporting our hypothesis that the expression of these heterozygous mutations as partial GH insensitivity syndrome depends on the genetic makeup of the person.

Body Height↗
PubMed1996

Physician and clinic charges for diagnosing growth hormone deficiency.

Physician and clinic charges for diagnosing growth hormone deficiency (GHD) in children are not generally known, whereas the charges for purchasing growth hormone (GH) are known. We recently surveyed the charges submitted to third-party payers for diagnosing GHD in five pediatric endocrine clinics throughout the United States: the Albert Einstein College of Medicine, Baylor College of Medicine, Health Science Schools of the State University of New York at Buffalo, Oregon Health Sciences University, and the University of Chicago. The financial data analyzed included charges for physician services and for GH testing. Different approaches to the medical examination of children with suspected GHD at these clinics prevented any comparison of physician or GH testing charges. However, the charges for diagnosing GHD could be determined for each pediatric endocrine clinic if the methods of examination were not considered. Contractual adjustments, net revenues, costs, and net margins were not surveyed. Subjective comments from the study sites suggest significantly reduced reimbursement amounts. We conclude that the total charges for diagnosing GHD submitted to third-party payers at these institutions averaged $1719.

Child↗
PubMed1978

Direct inhibition of Leydig cell function by estradiol.

Suppression of plasma testosterone levels from a mean of 760 ng/dl to a mean of 295 ng/dl could be induced in normal young adult men 24 h after a single injection of 2 mg aqueous 17 beta-estradiol. Maximum suppression to 123 ng/dl was noted 36 h after estradiol administration. Neither LH nor FSH levels were similarly affected. After administration of 5000 IU hCG to a similar group of subjects, daily blood samples were obtained for testosterone and estrogen. Maximum testosterone levels of 2060 ng/dl (basal, 784 ng/dl) were seen 96 h after hCG administration. Maximum estrogen levels of 13 pg/ml (basal 73 pg/ml) were seen 36 h after hCG administration. The testosterone response to hCG could be attenuated by preceding hCG administration with an injection of 17 beta-estradiol. These results can be explained by the concept of enzyme inhibition; estrogen acts directly on the Leydig cell to effect changes in the activities of certain enzymes important for testosterone synthesis. Whether endogenous estrogen production by the Leydig cell may be important in this postulated short loop feedback is as yet unclear.

Adult↗
PubMed1977

alpha-Actinin and tropomyosin interactions with a hybrid complex of erythrocyte-actin and muscle-myosin.

alpha-Actinin isolated from dog muscle was used to incite antibodies in rabbits, Antibodies, purified by affinity chromatography on CNBr-Sepharose coupled with alpha-actinin and then ferritin-labeled were found to localize on the Z disc of muscle sarcomeres. Molecules of alpha-actinin as an adsorbed monolayer on the surface of polystyrene Lytron particles could bind muscle-actin and tropomyosin from solution. Both the ATPase activity and superprecipitation of an erythrocyte-actin and muscle-myosin hybrid actomyosin complex were altered by alpha-actinin, while tropomyosin diminished these alpha-actinin effects. The binding properties of alpha-actinin are consistent with those of an anchoring protein for microfilaments in nonmuscle cells.

Actinin↗