93,196 research outputs found
Chart of head length of pouch young tammar wallabies (Macropus eugenii) of known age
This is a chart of the head lengths of pouch young tammar wallabies (Macropus eugenii)of known age, enabling the ages of pouch young of unknown age to be determined by their head lengt
CtBP impedes JNK- and Upd/STAT-driven cell fate misspecifications in regenerating Drosophila imaginal discs.
Regeneration following tissue damage often necessitates a mechanism for cellular re-programming, so that surviving cells can give rise to all cell types originally found in the damaged tissue. This process, if unchecked, can also generate cell types that are inappropriate for a given location. We conducted a screen for genes that negatively regulate the frequency of notum-to-wing transformations following genetic ablation and regeneration of the wing pouch, from which we identified mutations in the transcriptional co-repressor C-terminal Binding Protein (CtBP). When CtBP function is reduced, ablation of the pouch can activate the JNK/AP-1 and JAK/STAT pathways in the notum to destabilize cell fates. Ectopic expression of Wingless and Dilp8 precede the formation of the ectopic pouch, which is subsequently generated by recruitment of both anterior and posterior cells near the compartment boundary. Thus, CtBP stabilizes cell fates following damage by opposing the destabilizing effects of the JNK/AP-1 and JAK/STAT pathways
Restorative proctocolectomy with ileal pouch reservoir in ulcerative colitis : the first series from Malta
Seventy five to eighty percent of patients with ulcerative colitis are more or less satisfactorily treated medically. Surgery cures the disease, but because proper surgical therapy has until recently necessitated a permanent ileostomy, physicians and patients are understandably reluctant to agree to definitive surgical treatment until absolutely necessary.peer-reviewe
Genetic regulation of pituitary gland development in human and mouse
Normal hypothalamopituitary development is closely related to that of the forebrain and is dependent upon a complex genetic cascade of transcription factors and signaling molecules that may be either intrinsic or extrinsic to the developing Rathke’s pouch. These factors dictate organ commitment, cell differentiation, and cell proliferation within the anterior pituitary. Abnormalities in these processes are associated with congenital hypopituitarism, a spectrum of disorders that includes syndromic disorders such as septo-optic dysplasia, combined pituitary hormone deficiencies, and isolated hormone deficiencies, of which the commonest is GH deficiency. The highly variable clinical phenotypes can now in part be explained due to research performed over the last 20 yr, based mainly on naturally occurring and transgenic animal models. Mutations in genes encoding both signaling molecules and transcription factors have been implicated in the etiology of hypopituitarism, with or without other syndromic features, in mice and humans. To date, mutations in known genes account for a small proportion of cases of hypopituitarism in humans. However, these mutations have led to a greater understanding of the genetic interactions that lead to normal pituitary development. This review attempts to describe the complexity of pituitary development in the rodent, with particular emphasis on those factors that, when mutated, are associated with hypopituitarism in humans
Auto-spermatophore extrusion in male crickets
The reproductive cycle of the male cricket consists of
the mating stage and the sexually refractory stage. The
latter is further divided into the first refractory stage
(RS1) from spermatophore extrusion in copulation to
spermatophore preparation after copulation, and the
second refractory stage (RS2) from spermatophore
preparation to recommencement of a calling song. RS2 is
time-fixed and unaffected by the female or by stress, hence
RS2 is assumed to be controlled by the reproductive timer.
Previously, we suggested that the timer is located in the
terminal abdominal ganglion (TAG), because functional
inactivation of the TAG by local cooling lengthened RS2 in
proportion to cooling time. To obtain further evidence
of timer localization and to examine the operation of
the timer in dissected animals, we investigated the
characteristics of auto-spermatophore extrusion, a
phenomenon in which males eject the mature
spermatophore themselves without any prior courtship.
The occurrence of auto-spermatophore extrusion was
100% in dissected males with the TAG separated,
compared to 1.7% in intact males. The time interval
(SPaSE) between spermatophore preparation and autospermatophore
extrusion was comparable to RS2
measured by the calling song. Spike recording from a
genital motor neurone in the separated TAG indicated
that burst discharge associated with auto-spermatophore
extrusion occurred with a SPaSE comparable to RS2.
Other efferent neurones, some of which were identified as
dorsal unpaired median (DUM) neurones, showed a timedependent
spike frequency increase during SPaSE. These
results strengthen our previous conclusion that the
reproductive timer is located within the TAG, and
demonstrate that the timer functions normally even when
the TAG is separated from the central nervous system.</p
Identification and characterization of the dominant thermal resistance in lithium-ion batteries using operando 3-omega sensors
Poor thermal transport within lithium-ion batteries fundamentally limits their performance, safety, and lifetime, in spite of external thermal management systems. All prior efforts to understand the origin of batteries' mysteriously high thermal resistance have been confined to ex situ measurements without understanding the impact of battery operation. Here, we develop a frequency-domain technique that employs sensors capable of measuring spatially resolved intrinsic thermal transport properties within a live battery while it is undergoing cycling. Our results reveal that the poor battery thermal transport is due to high thermal contact resistance between the separator and both electrode layers and worsens as a result of formation cycling, degrading total battery thermal transport by up to 70%. We develop a thermal model of these contact resistances to explain their origin. These contacts account for up to 65% of the total thermal resistance inside the battery, leading to far-reaching consequences for the thermal design of batteries. Our technique unlocks new thermal measurement capabilities for future battery research
Poor Outcomes of Complicated Pouch-Related Fistulas after Ileal Pouch-Anal Anastomosis Surgery
Background and Aims: Development of a pouch-related fistula tract is an uncommon but highly morbid complication to restorative proctocolectomy with ileal pouch-anal anastomosis. Pouch failure with permanent ileostomy is reported in 21%–30% of patients, yet the factors contributing to pouch excision remain poorly defined. The aim of this study was to determine the incidence and treatment results of complicated pouch-related fistula, as well as to evaluate factors involved in excision after pouch failure. Material and Methods: The study was conducted as a retrospective study. All patients with diagnosed pouch-related fistulas were registered with information related to fistula classification, treatments, and outcome. Results and Conclusion: The final analysis included 48 (10.7%) of the 447 total ileal pouch-anal anastomosis patients with complicated pouch-related fistulas. Pouch-vaginal fistulas, pouch-perianal fistulas, and other pouch-related fistulas were observed in 19 (63%), 29 (60%), and 10 (21%) patients, respectively, corresponding to an accumulated risk of 8%, 6%, and 2%, respectively. Time from ileal pouch-anal anastomosis surgery to fistula presentation was 24 (0.2–212) months. Overall pouch failure, defined as pouch excision or a diverting stoma, was seen in 34 (71%) patients, while pouch excision was seen in 23 (48%) of the patients. Patients who developed Crohn’s disease had a significantly higher risk of pouch excision, as did patients with an early onset of the fistula after ileal pouch-anal anastomosis ( P = 0.006 and P = 0.007, respectively). In conclusion, the present study demonstrated a high risk of pouch failure in patients with complicated pouch-related fistulas. Furthermore, it showed that Crohn’s disease and the development of early onset fistulas are associated with pouch excision. </jats:sec
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