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Biomedical subjects

B Greenstein

Publications and source records attributed to B Greenstein.

11 recordsLinked to original sources
PubMed2001

Estrogen and progesterone receptors in murine models of systemic lupus erythematosus.

Estrogens are believed to play a role in the etiology of both human and murine systemic lupus erythematosus (lupus; SLE), presumably through the agency of their cellular receptor proteins. There is now considerable interest in the molecular mechanism of action of estrogens in immune tissues, particularly with regard to autoimmune disorders, which are generally more prevalent in women. In this laboratory, an attempt is being made to characterize estrogen receptors in murine models of SLE and to try and relate this to estrogen receptor function in vivo. The initial aim was to compare binding properties of estrogen receptors in brain, reproductive and immune tissues of BALB/c and MRL/MP-lpr/lpr mice. The latter strain spontaneously develops an autoimmune disease resembling human systemic lupus erythematosus (lupus; SLE). It is hypothesized that estradiol, through its receptors, mediates the progression of murine SLE, and that in autoimmune disease, the estrogen receptor is functionally and/or structurally changed. Initial studies suggest that there are differences in estrogen receptors between BALB/c mice, which do not get autoimmune disease, and two strains that do, MRL/MP-lpr/lpr and NZB/W mice. In MRL mice, these differences may be reflected in impaired priming of the progesterone receptor.

Animals↗
PubMed2000

Strain differences in binding properties of estrogen receptors in immature and adult BALB/c and MRL/MP-lpr/lpr mice, a model of systemic lupus erythematosus.

The aim was to compare binding properties of estrogen receptors in brain, reproductive and immune tissues of immature and adult female BALB/c mice, and in the same tissues of MRL/MP-lpr/lpr mice. The latter strain spontaneously develops an autoimmune disease resembling human systemic lupus erythematosus (lupus; SLE). It is hypothesized that estradiol, through its receptors, mediates the progression of murine SLE. High-speed cytosols were prepared from hypothalamus, spleen, thymus and uterus of both strains, and incubated with the synthetic estrogen (3)H-moxestrol (NEN). Scatchard plots were derived from binding isotherms obtained after in vitro incubation. In addition, cervical lymph nodes from MRL mice could be used, but were too small in BALB/c mice. There was a significant increase in the affinity of the binding reaction i.e. a decrease in the apparent molar dissociation constant (Kd), in immune tissues and uterus with maturation in MRL but not BALB/c mice, whose tissues had, overall, a lower affinity for (3)H-moxestrol. Receptor concentrations were significantly higher in spleen and cervical lymph nodes of adult compared with immature MRL mice, but the opposite pattern was observed in BALB/c mouse spleen on maturation. These properties of estrogen receptors in MRL mice may underlie estrogen-mediated exacerbation of murine SLE.

Age Factors↗
PubMed1999

Evidence for sexual dimorphism of estrogen receptors in hypothalamus and thymus of neonatal and immature Wistar rats.

It is hypothesized that the rat thymus is sexually differentiated. To begin testing this, we used the 5-day-old rat, whose hypothalamus is sexually differentiated during this period. Cytosolic estrogen receptors (ER) were measured in cytosols prepared from the brain, thymus and uterus of Wistar rats at 5, 18 and 30 days post-partum. ER concentrations were significantly higher in hypothalamus in cytosols of female 5-day-old rats, and this difference had disappeared by day 18. The pattern in thymus was identical to that observed in hypothalamus, suggesting the presence in the thymus of the aromatase system that converts androgen to estrogen, and that estrogen-mediated sexual differentiation of thymus might be proceeding at 5 days. Unlike the case for hypothalamus, no experimental model exists at present for testing functional sexual differentiation in thymus. Therefore we tested the effects of aromatase inhibitors on estrogen receptor activity in thymus well after the five-day period, and before atrophy of the thymus has commenced. Male and female rats were implanted at 15 days of age with SILASTIC implants containing 5 mg of estradiol or with 25 mg of the aromatase inhibitor 4-hydroxyandrostenedione (4-OHA) and cytosolic ER prepared at 30 days and activity measured. Administration of estradiol resulted in failure to detect available receptor, suggesting that the binding components measured were ER. After 4-OHA administration, ER concentrations were significantly increased in cytosols from male but not female hypothalamus and thymus. There is therefore a basis for exploring further the hypothesis that rat thymus is sexually differentiated.

Age Factors↗
PubMed1997

Cosmetic Plastic Surgery in Adolescents.

Perceived or real physical defects may be important for an adolescent trying to establish self-image and adjust socially. Port-wine stains, breasts too small or too large, ethnic nose, prominent ears or chin, excess of adipose tissue-all these "defects" can lead to loss of self-esteem and have severe consequences with regard to an adolescent's development. This chapter discusses surgical procedures that can help adolescents change their physical appearance and consequently improve their self-confidence and social integration.

Journal Article↗
PubMed1993

Systemic lupus erythematosus: sex hormones in male patients.

Systemic lupus erythematosus (SLE) is a rare disease in males. There is evidence that a functional state of hypoandrogenism is important in the pathogenesis of the disease. We analysed the levels of several hormones (follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), estradiol (E2), free estradiol (FE2) and prolactin (PRL)) in 17 male SLE patients and 17 male healthy controls with similar age distribution. Three lupus patients were excluded from the analysis due to previous cyclophosphamide therapy or pre-puberty. Thus 14 male lupus patients were eligible for the study. Six of the 14 SLE patients (43%) showed at least one abnormal level of FSH, LH or T. There were no abnormalities in these hormones in the 17 controls. This difference was significant (P < 0.01). In five of these 6 male patients (36% of all lupus patients) the hormonal profile was compatible with a functional state of hypoandrogenism (high LH and/or low T). The ratio E2/T (estradiol/testosterone:pmol/nmol) was also significantly higher in the SLE group (average = 6.5; SD 4.3) when compared with that of the control group (average 4.2; SD 1.2; Mann-Whitney rank sum test: P < 0.03). There were no significant differences in E2, FE2 or PRL between lupus patients and controls. We did not confirm the notion that left-handedness is frequent in male lupus as all our patients were right-handed. We found a significantly higher prevalence of sex hormone abnormalities in male lupus patients when compared with healthy controls with a similar age distribution.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Problems and complications encountered in replantation surgery.

The surgical techniques involved in a discipline as comparatively new and complex as replantation might be expected to result in a significant rate of complications. However, serious complications related to replantation surgery remain relatively infrequent. Meticulous attention to detail helps to avoid predicaments, minimizes potential problems, and allows the surgeon to correct the occasional complication that arises.

Amputation Stumps↗
PubMed1985

The fate of tendon healing after restoration of the integrity of the tendon sheath with autogenous vein grafts.

This experimental study in the chicken model compares the results of sheath closure during primary tendon surgery. Sheath closure after tendon grafting was accomplished by trapdoor of the original sheath, vein patch, and vein conduit. After casting in flexion for 14 days, the operated foot and digits were taken through a full passive range of motion every 3 days. At the 28th postoperative day, all immobilization was removed and free active range of motion and daily perching began. Active flexion was measured after death by continuous traction on the proximal profundus tendon: simulated active flexion. The unoperated contralateral foot served as the control. All operated middle toes achieved significantly greater functional return when the sheath was restored either with trap-door closure, vein conduit, or vein patch compared with simple excision of the sheath. The results indicate the efficacy of sheath closure as well as the possibility of utilizing vein patches or conduits during primary tendon repair.

Animals↗
PubMed1985

Neurovascular flaps to the hand.

The surgical return of sensibility in the injured upper extremity remains a major goal for the reconstructive surgeon. Free flaps have created the opportunity for successful reconstruction in those patients in whom irreplaceable sensory end organs have been destroyed. In addition, well-vascularized composite tissues may be transferred in continuity with the dorsalis pedis and forearm flaps, allowing for one-stage reconstructions. Extra blood supply is brought to a scarred area in a single step, unlike the multi-stage transfer of distant parasitic tissue. Donor site morbidity remains a problem with many of these flaps, and skin grafts are often required. Many of the larger flaps do not have a close skin match to the skin of the volar hand. There are reports of achievement of protective sensibility with use of all of these flaps. However, experience with fine two-point discrimination has been limited to only the first web space flap. This return to near normal sensibility in the hand remains a standard by which all these flaps must be judged.

Dermatologic Surgical Procedures↗
PubMed1983

Replantation of amputated parts of the penis, nose, ear, and scalp.

The primary restoration of traumatically amputated digits is now routinely possible through the use of microvascular and microneural surgical techniques. The anatomy of the scalp, penis, ear, and nose makes them suitable subjects for application of these techniques. It has been the belief of many authors, as summarized by Grabb and Dingman, that venous congestion is the usual explanation for failure of replanted tissue without microsurgical repairs. Unsuitable veins of small caliber and venous congestion remain as the bane of the microsurgeon. The relative infrequency of these amputations makes it necessary to continue careful study of all reports regarding their microsurgical replantation. There is every reason to believe that increased surgical experience will result in more favorable outcomes.

Ear, External↗