336 research outputs found
Developing teachers
A 1929 text for science teachers describes a
successful science teacher as one who:
“...knows his own subject ... is widely read in
other branches of science ... knows how to
teach ... is able to express himself lucidly ... is skillful in
manipulation ... is resourceful both at the
demonstration table and in the laboratory ... is a
logician to his fingertips ... is something of a
philosopher ... is so far an historian that he can sit down
with a crowd of [students] and talk to them about the
personal equations, the lives, and works of such
geniuses as Galileo, Newton, Faraday and Darwin. More
than this, he is an enthusiast, full of faith in his own
particular work.”We are more used to teachers being talked down to, of
how they should teach and what they should teach. It is
time for the teacher educators, curriculum designers,
administrators and policy makers to show in practice
what they preach to the teachers. In doing so, they will
also counter the usual criticisms of such approaches
being too time consuming and how the entire syllabus
would not be covered this way. The central issue is not
the syllabus but the goals of our education
Ultrasonographic detection of nuchal cord: required or not
Background: Nuchal cord is defined as an umbilical cord that passes 360 around the neck. From a long time nuchal cord is considered as one of the cause for birth asphyxia and neonatal complications. For ultrasonographic detection of nuchal cord and use of colour Doppler for the same is emphasized a lot in literature. On the other side studies are there that don’t support the ultrasonographic detection of nuchal cord. Practically also on one sides it makes the attendants more anxious and results in unnecessary caesarean section as well as results in malpractice also. This study was conducted to assess the requirement of nuchal cord detection at any phase of gestation.Methods: This is a retrospective study conducted in the department of obstetrics & gynecology in a rural tertiary health care centre in one year duration. All the patients having nuchal cord at the time of delivery or caesarean section were included in the study. The case reports were analysed retrospectively for neonatal outcome and progress of labour. Results: The incidence of nuchal cord was 6.63%, irrespective of number of loops. The incidence of single loop was 5.32% double loop was 1.14% three loop was 0.17%. One patient had four loops of cord around neck and one patient had true knot in the cord but neonatal outcome was absolutely normal in both patients. The profile of patients was discussed in Table 1. A total of 85% patients were less than 30 year age group with literacy level of 65% and 55% patients were primigravida.20 patients developed prolonged labour, 13 patients among these responded to oxytocin and delivered normally and rest 07 underwent lower segment caesarean section for non-progress of labour or fetal distress. The duration of labour was found prolonged in patients w and triple nuchal cords. 53 (27.60%) fetus had unfavourable APGAR at birth, among these 20 had single tight loop of cord around neck, recovered soon as the cord was clamped and cut. Among rest 33 fetus 03 had three loops of cord around neck, 07 had two tight loops of cord around neck, in rest 23 fetus loops of cord were present besides that other factors like prematurity (11), severe preeclampsia (06), chorioamnionits (02) , antepartum hemorrhage (04) were also present, may be responsible for fetal distress.Conclusions: Routine ultrasonographic nuchal cord detection is not required and should not alter obstetric management of the patient.
Hurdles in starting laparoscopy in a rural medical college: our experience
Background: Although laparoscopy surgery has certain proved advantages over open surgery like less scarring, less postoperative pain, early return to work etc. but has a long learning curve. The pressure of feeling we are behind as a surgeon if we don’t embrace laparoscopy made us to take it on. With this paper we want to share our experiences i.e. beginner problem we faced, efforts and modification we adopted and current status of our journey. The aim of the study was to highlight the difficulties in starting laparoscopic surgeries and how to overcome them.Methods: This is a retrospective study of all laparoscopic procedures performed in our newly established government medical college in rural India was started from 2013.Results: We have performed cases of 27 diagnostic laparoscopy, 10 cases of laparoscopic ovarian cystectomy, 09 cases of ectopic pregnancy and cases of LAVH and 05 cases of TLH. Over a period of about two years out of total only 8 cases were performed in first year of study. It was our technical deficiency, nonavailability of mentor, anesthetists’ reluctance for general anaesthesia due to prolonged duration of surgery and administrative pressure of long waiting list. To overcome these problems we underwent lap training with experts, attended CMEs, conferences and convinced anesthetists and administration for these surgeries. We also selected and trained our O.T. staff about technical demands of laparoscopy.Conclusions: Start by doing what is necessary; then do whats possible and suddenly you are doing impossible. However conversion to open surgery should be kept at low threshold rather than landing yourself and patient in complications
Mouse models of preterm birth: Suggested assessment and reporting guidelines
Preterm birth affects approximately 1 out of every 10 births in the United States, leading to high rates of mortality and long-term negative health consequences. To investigate the mechanisms leading to preterm birth so as to develop prevention strategies, researchers have developed numerous mouse models of preterm birth. However, the lack of standard definitions for preterm birth in mice limits our field\u27s ability to compare models and make inferences about preterm birth in humans. In this review, we discuss numerous mouse preterm birth models, propose guidelines for experiments and reporting, and suggest markers that can be used to assess whether pups are premature or mature. We argue that adoption of these recommendations will enhance the utility of mice as models for preterm birth
Mueller matrix imaging for collagen scoring in mice model of pregnancy
Preterm birth risk is associated with early softening of the uterine cervix in pregnancy due to the accelerated remodeling of collagen extracellular matrix. Studies of mice model of pregnancy were performed with an imaging Mueller polarimeter at different time points of pregnancy to find polarimetric parameters for collagen scoring. Mueller matrix images of the unstained sections of mice uterine cervices were taken at day 6 and day 18 of 19-days gestation period and at different spatial locations through the cervices. The logarithmic decomposition of the recorded Mueller matrices mapped the depolarization, linear retardance, and azimuth of the optical axis of cervical tissue. These images highlighted both the inner structure of cervix and the arrangement of cervical collagen fibers confirmed by the second harmonic generation microscopy. The statistical analysis and two-Gaussians fit of the distributions of linear retardance and linear depolarization in the entire images of cervical tissue (without manual selection of the specific regions of interest) quantified the randomization of collagen fibers alignment with gestation time. At day 18 the remodeling of cervical extracellular matrix of collagen was measurable at the external cervical os that is available for the direct optical observations in vivo. It supports the assumption that imaging Mueller polarimetry holds promise for the fast and accurate collagen scoring in pregnancy and the assessment of the preterm birth risk
Reduced Bone Mass and Muscle Strength in Male 5α-Reductase Type 1 Inactivated Mice
Androgens are important regulators of bone mass but the relative importance of testosterone (T) versus dihydrotestosterone (DHT) for the activation of the androgen receptor (AR) in bone is unknown. 5α-reductase is responsible for the irreversible conversion of T to the more potent AR activator DHT. There are two well established isoenzymes of 5α-reductase (type 1 and type 2), encoded by separate genes (Srd5a1 and Srd5a2). 5α-reductase type 2 is predominantly expressed in male reproductive tissues whereas 5α-reductase type 1 is highly expressed in liver and moderately expressed in several other tissues including bone. The aim of the present study was to investigate the role of 5α-reductase type 1 for bone mass using Srd5a1−/− mice. Four-month-old male Srd5a1−/− mice had reduced trabecular bone mineral density (−36%, p<0.05) and cortical bone mineral content (−15%, p<0.05) but unchanged serum androgen levels compared with wild type (WT) mice. The cortical bone dimensions were reduced in the male Srd5a1−/− mice as a result of a reduced cortical periosteal circumference compared with WT mice. T treatment increased the cortical periosteal circumference (p<0.05) in orchidectomized WT mice but not in orchidectomized Srd5a1−/− mice. Male Srd5a1−/− mice demonstrated a reduced forelimb muscle grip strength compared with WT mice (p<0.05). Female Srd5a1−/− mice had slightly increased cortical bone mass associated with elevated circulating levels of androgens. In conclusion, 5α-reductase type 1 inactivated male mice have reduced bone mass and forelimb muscle grip strength and we propose that these effects are due to lack of 5α-reductase type 1 expression in bone and muscle. In contrast, the increased cortical bone mass in female Srd5a1−/− mice, is an indirect effect mediated by elevated circulating androgen levels
Quantitative Evaluation of Collagen Crosslinks and Corresponding Tensile Mechanical Properties in Mouse Cervical Tissue during Normal Pregnancy
The changes in the mechanical integrity of the cervix during pregnancy have implications for a successful delivery. Cervical collagens are known to remodel extensively in mice with progressing gestation leading to a soft cervix at term. During this process, mature crosslinked collagens are hypothesized to be replaced with immature less crosslinked collagens to facilitate cervical softening and ripening. To determine the mechanical role of collagen crosslinks during normal mouse cervical remodeling, tensile load-to-break tests were conducted for the following time points: nonpregnant (NP), gestation day (d) 6, 12, 15, 18 and 24 hr postpartum (PP) of the 19-day gestation period. Immature crosslinks (HLNL and DHLNL) and mature crosslinks (DPD and PYD) were measured using ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). There were no significant changes in the total immature crosslink density (HLNL+DHLNL mol per collagen mol) throughout normal mouse gestation (range: 0.31–0.49). Total mature crosslink density (PYD+DPD mol per collagen mol) decreased significantly in early softening from d6 to d15 (d6: 0.17, d12: 0.097, d15: 0.026) and did not decrease with further gestation. The maturity ratio (total mature to total immature crosslinks) significantly decreased in early softening from d6 to d15 (d6: 0.2, d15: 0.074). All of the measured crosslinks correlated significantly with a measure of tissue stiffness and strength, with the exception of the immature crosslink HLNL. This data provides quantitative evidence to support the hypothesis that as mature crosslinked collagens decline, they are replaced by immature collagens to facilitate increased tissue compliance in the early softening period from d6 to d15
17‐α estradiol ameliorates age‐associated sarcopenia and improves late‐life physical function in male mice but not in females or castrated males
Pharmacological treatments can extend mouse lifespan, but lifespan effects often differ between sexes. 17‐α estradiol (17aE2), a less feminizing structural isomer of 17‐β estradiol, produces lifespan extension only in male mice, suggesting a sexually dimorphic mechanism of lifespan regulation. We tested whether these anti‐aging effects extend to anatomical and functional aging—important in late‐life health—and whether gonadally derived hormones control aging responses to 17aE2 in either sex. While 17aE2 started at 4 months of age diminishes body weight in both sexes during adulthood, in late‐life 17aE2‐treated mice better maintain body weight. In 17aE2‐treated male mice, the higher body weight is associated with heavier skeletal muscles and larger muscle fibers compared with untreated mice during aging, while treated females have heavier subcutaneous fat. Maintenance of skeletal muscle in male mice is associated with improved grip strength and rotarod capacity at 25 months, in addition to higher levels of most amino acids in quadriceps muscle. We further show that sex‐specific responses to 17aE2—metabolomic, structural, and functional—are regulated by gonadal hormones in male mice. Castrated males have heavier quadriceps than intact males at 25 months, but do not respond to 17aE2, suggesting 17aE2 promotes an anti‐aging skeletal muscle phenotype similar to castration. Finally, 17aE2 treatment benefits can be recapitulated in mice when treatment is started at 16 months, suggesting that 17aE2 may be able to improve aspects of late‐life function even when started after middle age.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148386/1/acel12920_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148386/2/acel12920.pd
Aromatase expression is increased in BRCA1 mutation carriers
<p>Abstract</p> <p>Background</p> <p>Until recently, the molecular mechanisms explaining increased incidence of ovarian and breast cancers in carriers of <it>BRCA1 </it>gene mutations had not been clearly understood. Of significance is the finding that BRCA1 negatively regulates aromatase expression <it>in vitro</it>. Our objective was to characterise aromatase gene <it>(CYP19A1) </it>and its promoter expression in breast adipose and ovarian tissue in <it>BRCA1 </it>mutation carriers and unaffected controls.</p> <p>Methods</p> <p>We measured aromatase transcripts, total and promoter-specific (PII, PI.3, PI.4) in prophylactic oophorectomy or mastectomy, therapeutic mastectomy, ovarian and breast tissue from unaffected women.</p> <p>Results</p> <p>We demonstrate that the lack of functional BRCA1 protein correlates to higher aromatase levels in 85% of <it>BRCA1 </it>mutation carriers. This increase is mediated by aberrant transcriptional regulation of aromatase; in breast adipose by increases in promoter II/I.3 and I.4-specific transcripts; and in the ovary with elevation in promoter I.3 and II-specific transcripts.</p> <p>Conclusion</p> <p>Understanding the link between BRCA1 and aromatase is significant in terms of understanding why carcinogenesis is restricted to estrogen-producing tissues in <it>BRCA1 </it>mutation carriers.</p
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