Sexual differentiation in gonadal dysgenesis is commonly asymmetrical. In patients with true hermaphroditism there may be an ovary and mullerian duct on 1 side, and a testis and wolffian duct on the ...other side. Such asymmetry suggests that testicular hormones only act locally at this early stage of sexual differentiation. We tested the hypothesis that testosterone reaches the wolffian duct by transport down the duct rather than by simple diffusion.
Mouse 14-day urogenital ridges were placed in organ culture and microinjected with testosterone-albumin-fluorescein isothiocyanate.
At 17 hours fluorescence was found throughout the wolffian duct and by 48 hours it was maximal in the dilated caudal end.
Our results support the hypothesis that androgens may be transported along the wolffian duct. Secretion of testicular hormones into the wolffian duct may maintain hormone levels in the biologically active range.
Both the RATE Project (American Association of Colleges for Teacher Education (AACTE), 1988-1995) and Teacher Quality: A Report on the Preparation of Public School Teachers (U.S. Department of ...Education, National Center for Education Statistics, 1999) identified areas of development to ascertain how well professional teachers and preservice teachers believed their teacher preparation programs prepared them for their roles as elementary, middle, or secondary level teachers.
After months of pandemic-related hardships and huge disruptions to education, I feel an extra responsibility this year to creatively re-engage my students in math. This is especially important ...because a crucial support structure was lost during remote instruction. When they are physically in the classroom, my students work collaboratively to solve problems, share solution strategies, and make connections between those strategies. They build and exist in a community in which they support one another and learn and grow together. During remote learning, the use of breakout rooms for small group work helped, but it was often a poor substitute for in-person connections. As we work to bring students back to in-person learning, here, the five steps to help them reconnect with the joy and creativity of problem solving are presented.
We investigated the neonatal piglet as a possible animal model for cryptorchidism and to determine whether calcitonin gene-related peptide (CGRP), which has been proposed to regulate inguinoscrotal ...testicular descent, could induce testicular descent in piglets with congenital cryptorchidism.
We examined 38 cryptorchid piglets to document the anatomy in 8 and to investigate the role of CGRP in 30. The 2-week-old piglets were allocated randomly to receive a mini-osmotic pump containing CGRP at various concentrations or phosphate buffered saline. The pump was inserted surgically into the ipsilateral scrotum, with the contents blinded to the surgeon. The positions of the testes, pump and anatomical landmarks were measured and photographed. The pigs were sacrificed and dissected 2 weeks later, and the positions were remeasured and photographed. The testes were examined histologically.
The 3 variants of cryptorchidism observed were intra-abdominal in 20 cases, inguinal in 9 and lateral inguinal ectopic in 9. CGRP had no effect on intra-abdominal or ectopic testes. In contrast, for inguinal testes exogenous CGRP caused a slight but significant 10 +/− 7.9 mm. descent towards the pump in 5 cases compared to −2.9 +/− 5.8 mm. in 4 controls.
Exogenous CGRP stimulated migration of inguinal testes that had been arrested in the line of descent while ectopic testes did not respond. These results support a role for CGRP in testicular descent and suggest that a slow release depot preparation might be useful as a possible treatment in some forms of cryptorchidism.
To study the effect of müllerian inhibiting substance on testicular germ cell development, especially on gonocytes, whole testes (156) from newborn mice were cultured for 1 to 7 days in vitro. The ...synthetic medium contained either 10% fetal calf serum, which itself contains endogenous müllerian inhibiting substance, or transferrin, insulin and retinoic acid. Human recombinant müllerian inhibiting substance, rabbit antiserum against müllerian inhibiting substance and/or normal rabbit serum was added to some cultures. The cultured testes were fixed in Stieve's fixative and stained with hematoxylin and eosin, and the numbers and types of germ cells per tubule were counted under a light microscope. Preliminary studies showed that germ cell development in newborn mouse testes was similar in vitro to that observed in vivo, except for delay in vitro. Normal germ cell maturation from gonocytes to primary spermatocytes occurred in testes cultured with 10% fetal calf serum only (i), 10% fetal calf serum plus müllerian inhibiting substance plus anti-müllerian inhibiting substance antibody (ii), 10% fetal calf serum plus normal rabbit serum (iii) and transferrin, insulin and retinoic acid plus müllerian inhibiting substance (iv). Maturation from gonocytes to A-type spermatogonia was arrested in testes cultured with 10% fetal calf serum plus anti-müllerian inhibiting substance antibody (p < 0.01), transferrin, insulin and retinoic acid alone (p < 0.001) and transferrin, insulin and retinoic acid plus müllerian inhibiting substance plus anti-müllerian inhibiting substance antibody (p < 0.001). The results are consistent with the hypothesis that müllerian inhibiting substance may be involved in postnatal gonocyte development and suggest that it may be useful to treat infertility associated with undescended testes.
Inventions for Sale Watts, Lisa
Technology review (1899),
10/1991, Letnik:
94, Številka:
7
Journal Article
Since MIT's patent and licensing office set up conflict-of-interest rules and let professors take stock in companies that license their products, MIT researchers have patented 112 inventions and ...arranged 80 licenses with industry.
The case they've waited for? Watts, Lisa
American journalism review,
04/2003, Letnik:
25, Številka:
3
Magazine Article
Watts discusses the ongoing case where four high school seniors, who are also staff members of the school publication, sued their school district for violating their First Amendment rights by ...illegally impounding the entire press run of the Dec 20 Wooster Blade. Their school superintendent took issue on a Blade news story about the school board giving preferential treatment to six student-athletes caught at a party with alcohol, but the students concerned swear the story is accurate.
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