Pig-to-baboon lung xenotransplantation: Extended survival with targeted genetic modifications and pharmacologic treatments

Galactosyl transferase knock-out pig lungs fail rapidly in baboons. Based on previously identified lung xenograft injury mechanisms, additional expression of human complement and coagulation pathway regulatory proteins, anti-inflammatory enzymes and self-recognition receptors, and knock-down of the β4Gal xenoantigen were tested in various combinations. Transient life-supporting GalTKO.hCD46 lung function was consistently observed in association with either hEPCR (n = 15), hTBM (n = 4), or hEPCR.hTFPI (n = 11), but the loss of vascular barrier function in the xenograft and systemic inflammation in the recipient typically occurred within 24 h. Co-expression of hEPCR and hTBM (n = 11) and additionally blocking multiple pro-inflammatory innate and adaptive immune mechanisms was more consistently associated with survival >1 day, with one recipient surviving for 31 days. Combining targeted genetic modifications to the lung xenograft with selective innate and adaptive immune suppression enables prolonged initial life-supporting lung function and extends lung xenograft recipient survival, and illustrates residual barriers and candidate treatment strategies that may enable the clinical application of other organ xenografts.     

Carboxy-terminal determinants of intracellular protein degradation

Using the amino-terminal domain of lambda repressor as a model system, we show that residues in an unstructured region at the extreme carboxyl terminus of the protein are important for determining its proteolytic susceptibility in Escherichia coli. Nonpolar amino acids are destabilizing when placed at the 5 carboxy-terminal residue positions, whereas charged and polar residues are stabilizing. The stabilizing effect of a single charged residue is greatest when it is at the terminal position and diminishes with increasing distance from the carboxyl terminus. The position of destabilizing sequences with respect to the free carboxyl terminus is important for their effect, but their distance from the folded portion of the protein is not important. Specific degradation of proteins with nonpolar carboxyl termini has been reconstituted in vitro using a partially pure, soluble fraction. This degradation is not ATP-dependent. Moreover, amino-terminal domain variants with nonpolar carboxy-terminal residues are still rapidly degraded in strains that are deficient in proteolysis of abnormal proteins. These data suggest that the degradation of amino-terminal domain variants with nonpolar carboxy-terminal residues involves proteolytic components distinct from those known to be important for the turnover of unfolded proteins in E. coli.     

Contract learning, clinical learning and clinicians.

Current trends in education and training emphasise that learners, whether they are school children, students or adults, need to acquire generic skills and personal characteristics which will enable them to become independent self-directed learners. This will enable them to continue the process of learning throughout their lives. Recent recommendations for the reform of undergraduate medical education, for training of hospital doctors and general practitioners, and the higher profile now being given to continuing medical education, reflect the strength of this particular educational current sweeping through all levels of medical education. Learning contracts, developed through negotiation between a teacher and a learner, are especially effective educational tools for stimulating independent learning. This paper examines the theoretical basis of contract-learning and its relevance to clinical settings.     

Relaxin stimulates expression of vascular endothelial growth factor in normal human endometrial cells in vitro and is associated with menometrorrhagia in women

Although the role of the reproductive hormone, relaxin, in rodents is well documented, its potential contribution to human reproduction is less well defined. In this study, we examine the effects of relaxin on human endometrial cells in vitro and describe the clinical effects of relaxin on menstrual flow in women. In cultured endometrial cells, relaxin specifically induces the expression of an angiogenic agent, vascular endothelial growth factor (VEGF). cAMP is implicated as a second messenger involved in VEGF stimulation. VEGF expression is temporally regulated in the endometrium, and our results suggest that relaxin, which is secreted by the corpus luteum and is present in the endometrium during the menstrual cycle and pregnancy, may be involved in regulating endometrial VEGF expression. Relaxin was recently tested in a clinical trial for efficacy in the treatment of progressive systemic sclerosis, and was administered at levels up to 10 times higher than that measured during pregnancy. The most frequent relaxin-related adverse event reported during the course of the study was the onset of menometrorrhagia, defined in this study as heavier-than-usual or irregular menstrual bleeding. The intensification of menstrual flow observed in these patients is consistent with the hypothesis that relaxin mediates neovascularization of the endometrial lining.     

Betamethasone valerate foam 0.12%: a novel vehicle with enhanced delivery and efficacy

BACKGROUND: A new topical formulation of betamethasone valerate (BMV) with enhanced dermal penetration has been developed. OBJECTIVE: These studies were designed to evaluate: (1) the relative bioavailability of BMV foam, and (2) the safety and efficacy of BMV foam in the treatment of scalp psoriasis as compared to a lotion formulation of BMV and placebo. METHODS: Safety and efficacy were evaluated in a randomized, multicenter, double-blind, active-and placebo-controlled trial in adult patients with moderate to severe scalp psoriasis. A separate study in 18 patients was conducted to evaluate the potential for suppression of the hypothalamic-pituitary-adrenal (HPA) axis. Relative bioavailability was measured using the human cadaver skin model. RESULTS: 72% of patients using BMV foam were clear or almost clear of disease at the end of 28-days of treatment as judged by the investigator's global assessment of response. Only 47% of BMV lotion patients and 21% of placebo showed a similar level of response. There was no evidence of increased toxicity or HPA-axis suppression for BMV foam, but assessment of relative bioavailability showed BMV penetration into the skin to be more than two-fold greater than from BMV lotion. CONCLUSIONS: A novel foam formulation with enhanced BMV bioavailability has been shown to be of increased efficacy in the treatment of scalp psoriasis without an associated increase in toxicity.     

Clobetasol propionate foam 0.05%: a novel vehicle with enhanced delivery

One hundred and eighty‐eight subjects with psoriasis of the scalp voluntarily participated in this multicenter, randomized, double‐blind, active, and placebo‐controlled study to evaluate the safety and efficacy of clobetasol propionate foam 0.05% (CP foam) relative to clobetasol propionate solution 0.05% (CP solution, Temovate^® scalp application). Adult male and female subjects with moderate to severe disease were assigned to one of four treatment groups in a 2 : 1 : 2 : 1 ratio (CP foam : placebo foam : CP solution : placebo solution). Moderate to severe disease was defined as involvement of at least 10% of the scalp and a minimum score of 2 (0, none; 1, mild; 2, moderate; 3, severe; 4, very severe) for each of the primary signs of psoriasis (erythema, scaling, plaque thickness). Subjects applied study medication to the entire scalp twice daily for 14 consecutive days and were required to use DHS shampoo. No other therapy to the scalp was allowed. Pruritus, scaling, erythema, and plaque thickness were evaluated on days 0, 7, and 15, and after 2 weeks off treatment on day 28. In addition, both the investigator and subject evaluated the global response to treatment at days 15 and 28 using a seven‐point grading scale (completely clear, almost clear, marked improvement, moderate improvement, slight improvement, no change, or worse). The number of subjects who were ‘‘completely clear’' or ‘‘almost clear’' (> 90% clearing) were lumped together to determine treatment success. Safety was assessed via standard clinical laboratory panels (chemistry, hematology, urinalysis), physical examination, vital signs, and reported adverse events. In addition to the clinical study, the potency of CP foam relative to five other dosage forms of CP, as well as to betamethasone valerate lotion 0.1%, was determined in 24 healthy male and female subjects using a modification of the new vasoconstrictor procedure. ¹ Products were randomly applied to 3.14 cm ² sites on the ventral forearms at a dose of 10 μL, covered with a nonocclusive guard, then removed after 3 h with dry, cotton swabs. Skin color was measured at ? 1, 1, 4, 8, 12, 24, and 30 h using a chromameter (Minolta, Ramsey, NJ). Vasoconstrictor potency was assessed from the area‐under‐the‐skin‐blanching curve (AUC) using the a* scale output of the chromameter. The percutaneous absorption of CP from both the foam and solution formulations was determined using the cadaver skin assay. ² Each product was applied to multiple sections of skin at a dose of 6–8 mg/cm ² , and the solution bathing the dermis was sampled at intervals and analyzed for CP content by high performance liquid chromatography. Investigators: Edwin A. Bronsky, md , Intermountain Clinical Research, Salt Lake City, UT; Frank E. Dunlap, md , Argus Research, Inc., Tuscon, AZ; Holly B. Faust, md , Indiana University, Indianapolis, IN; David P. Fivenson, md , Henry Ford Hospital, Detroit, MI; Alan M. Heller, md , San Jose Clinical Research, San Jose, CA; Paul A. Lehman, MS , University of Arkansas for Medical Sciences, Little Rock, AR; Dale E. Martin, md , Skin Surgery and Skin Tumor Medical Group of San Diego, San Diego, CA; Bruce H. Miller, md , Dermatology Associates Research Center, Portland, OR; S. David Miller, md , New England Research Center, North Dartmouth, MA; Jennie J. Muglia, md , Rhode Island Hospital, Providence, RI; Toivo E. Rist, md , Dermatology Associates of Knoxville, Knoxville, TN; Ronald C. Savin, md , Savin Dermatology Center, New Haven, CT; Linda F. Stein, md , Henry Ford Hospital, Detroit, MI; Kenneth J. Washenik, md , p h d , NYU Medical Center, New York, NY