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Biomedical subjects

Timothy Rowe

Publications and source records attributed to Timothy Rowe.

18 recordsLinked to original sources
PubMed2006

Impact of assisted hatching on the outcome of intracytoplasmic sperm injection: a prospective, randomized clinical trial and pregnancy follow-up.

OBJECTIVE: To evaluate the overall effect of assisted hatching (AH) on the implantation, pregnancy, and live birth rates in women undergoing intracytoplasmic sperm injection (ICSI) cycles; and to determine the effect of AH on the cytogenetic outcome (chromosomal constitution) of pregnancy. DESIGN: Prospective, randomized study. SETTING: Academic research environment. PATIENT(S): A total of 172 couples were enrolled in the study. INTERVENTION(S): Assisted hatching was carried out on day-3 ICSI embryos. MAIN OUTCOME MEASURE(S): Implantation, clinical pregnancy, and live birth rates; cytogenetic analysis of abortuses and umbilical cord blood samples from newborns. RESULT(S): Biochemical, clinical, and ongoing pregnancy rates were not significantly different between the AH and control groups. The implantation rate was higher in the AH group than in the control group (16% vs. 8%), especially in women aged > or =35 years. Postnatal umbilical cord blood samples were collected and cytogenetically analyzed from 39 live births (20 from the AH group, 19 from the control group). Two abnormal karyotypes were found (one AH, one control). There were seven spontaneous losses during the study interval. Six of the abortuses underwent cytogenetic study (five AH, one control), and four were found to have an abnormal karyotype (three AH, one control). CONCLUSION: We found that AH improves implantation rates of ICSI cycles and seems to be most effective in women aged > or =35 years. A larger sample size is needed to determine whether AH improves the take-home-baby rate. Assisted hatching did not affect the rate of chromosomal abnormalities in live births in this study.

Adult↗
PubMed2006

Cranial anatomy of the spade-headed amphisbaenian Diplometopon zarudnyi (Squamata, Amphisbaenia) based on high-resolution X-ray computed tomography.

The skull of the trogonophid amphisbaenian Diplometopon zarudnyi is described from high-resolution X-ray computed tomographic (HRXCT) imagery of a whole museum specimen preserved in ETOH. The skull was digitally resliced and disarticulated into individual elements, producing novel visualizations that allow detailed morphological analysis of its three-dimensionally complex structure. The prefrontal and jugal are absent in Diplometopon. The septomaxilla is present but hidden entirely from superficial view. In contrast to previous studies, we recognize a splenial fused to the compound bone of the mandible and a squamosal fused to the otic-occipital complex. Comparison of Diplometopon to the two other amphisbaenians previously described in comparable detail, Rhineura hatcherii and Amphisbaena alba, reveals a mosaic of cranial similarities and differences. Both Diplometopon and Rhineura exhibit a craniofacial angulation and expanded rostral blade related to use of the head as a digging tool, but the detailed architecture of these features is quite different. Additionally, whereas the snout of Rhineura exhibits a high degree of sculpturing and sensory innervation, this is not the case in Diplometopon. Unlike in Rhineura and Amphisbaena, the cranial elements of Diplometopon do not exhibit an extensive degree of overlap or complex interlocking sutures; instead, most of the cranial elements lie in loose apposition to each other. The degree to which this mosaic of features reflects functional demands, shared ancestry, and/or convergence is unclear in the absence of a stable hypothesis of amphisbaenian phylogeny.

Animals↗
PubMed2006

Description of a cranial endocast from a fossil platypus, Obdurodon dicksoni (Monotremata, Ornithorhynchidae), and the relevance of endocranial characters to monotreme monophyly.

A digital cranial endocast of the Miocene platypus Obdurodon dicksoni was extracted from high-resolution X-ray computed tomography scans. This endocast represents the oldest from an unequivocal member of either extant monotreme lineage and is therefore important for inferring character support for Monotremata, a clade that is not well diagnosed. We describe the Obdurodon endocast with reference to endocasts extracted from skulls of the three species of extant monotremes, particularly Ornithorhynchus anatinus, the duckbill platypus. We consulted published descriptions and illustrations of whole and sectioned brains of monotremes to determine which external features of the nervous system are represented on the endocasts. Similar to Ornithorhynchus, well-developed parafloccular casts and reduced olfactory bulb casts are present in the Obdurodon endocast. Reduction of the olfactory bulbs in comparison with tachyglossids and therian mammals is a potential apomorphy for Ornithorhynchidae. The trigeminal nuclei, ganglia, and nerves (i.e., trigeminal complex) are enlarged in Obdurodon, as evidenced by their casts on the endocast, as is the case in the extant platypus. The visibility of enlarged trigeminal nucleus casts on the endocasts of Obdurodon and Ornithorhynchus is a possible synapomorphy of Ornithorhynchidae. Electroreception and enlargement of the trigeminal complex are possible synapomorphies for Monotremata.

Animals↗
PubMed2006

Communicating.

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Canada↗
PubMed2006

Canadian Consensus Conference on menopause, 2006 update.

OBJECTIVE: To provide guidelines for health care providers on the management of menopause in asymptomatic healthy women as well as in women presenting with vasomotor symptoms, urogenital, sexual, and mood and memory concerns and on specific medical considerations, and cardiovascular and cancer issues. OUTCOMES: Prescription medications, complementary and alternative medicine (CAM), and lifestyle interventions are presented according to their efficacy in treating menopausal symptoms. EVIDENCE: MEDLINE and the Cochrane database were searched for articles from March 2001 to April 2005 in English on subjects related to menopause, menopausal symptoms, urogenital and sexual health, mood and memory, hormone therapy, CAM, and on specific medical considerations that affect the decision of which intervention to choose. VALUES: The quality of evidence is rated using the criteria described in the report of the Canadian Task Force on the Periodic Health Examination. Recommendations for practice are ranked according to the method described in this report (see Table 1). SPONSORS: The development of this consensus guideline was supported by unrestricted educational grants from Berlex Canada Inc, Lilly Canada, Merck Frosst, Novartis, Novogen, Novo Nordisk, Proctor and Gamble, Schering Canada, and Wyeth Canada.

Affect↗
PubMed2006

Fertility and a woman's age.

Women show a progressive decline in fecundity as they pass through the reproductive years. The decline in fecundity can be attributed to numerous potential causes, including changes in oocyte quality, the frequency and efficiency of ovulation, sexual function, the health of the uterus and the risk of pregnancy complications. Screening women for their ovarian reserve uses a number of biochemical and imaging strategies that have a limited ability to predict the likelihood of pregnancy with or without fertility treatment. Consideration of the decline infertility as a woman ages is an important and integral part of health care for women. Physicians and other caregivers must continue to counsel women about their potential fertility as they age, whether or not they are actively seeking pregnancy.

Adult↗
PubMed2005

Cranial anatomy of the extinct amphisbaenian Rhineura hatcherii (Squamata, Amphisbaenia) based on high-resolution X-ray computed tomography.

The fossilized skull of a small extinct amphisbaenian referable to Rhineura hatcherii Baur is described from high-resolution X-ray computed tomographic (HRXCT) imagery of a well-preserved mature specimen from the Brule Formation of Badlands National Park, South Dakota. Marked density contrast between bones and surrounding matrix and at bone-to-bone sutures enabled the digital disarticulation of individual skull elements. These novel visualizations provide insight into the otherwise inaccessible three-dimensionally complex structure of the bones of the skull and their relationships to one another, and to the internal cavities and passageways that they enclose. This study corrects several previous misidentifications of elements in the rhineurid skull and sheds light on skull construction generally in "shovel-headed" amphisbaenians. The orbitosphenoids in R. hatcherii are paired and entirely enclosed within the braincase by the frontals; this is in contrast to the condition in many extant amphisbaenians, in which a large azygous orbitosphenoid occupies a topologically distinct area of the skull, closing the anterolateral braincase wall. Rhineura hatcherii retains a vestigial jugal and a partially fused squamosal, both of which are absent in many extant species. Sculpturing on the snout of R. hatcherii represents perforating canals conveying sensory innervation; thus, the face of R. hatcherii receives cutaneous innervation to an unprecedented degree. The HRXCT data (available at www.digimorph.org) corroborate and extend previous hypotheses that the mechanical organization of the head in Rhineura is organized to a large degree around its burrowing lifestyle.

Animals↗
PubMed2005

Taking stock.

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Canada↗
PubMed2005

Connections.

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Canada↗
PubMed2004

Structure and function of the horn shark (Heterodontus francisci) cranium through ontogeny: development of a hard prey specialist.

The horn sharks (Heterodontidae: Chondrichthyes) represent one of four independent evolutions of durophagy in the cartilaginous fishes. We used high-resolution computed tomography (CT scanning) to visualize and quantify the mineralized tissue of an ontogenetic series of horn sharks. CT scanning of neonatal through adult California horn sharks (Heterodontus francisci) confirmed that this technique is effective for examining mineralized tissue in even small (<10 mm) specimens. The jaw joint is among the first areas to become mineralized and is the most heavily mineralized area in the cranium of a neonatal horn shark. The hyoid is also well mineralized, although the poorly mineralized molariform teeth indicate that the neonatal animal may be a suction feeder on softer prey. The symphysis of the jaws never mineralizes, in sharp contrast to the condition in the hard prey-crushing stingrays. Digitally reslicing the CT scans along the jaws allowed measurement of the second moment of area (Ina). Assuming that the jaws are made of the same material at all ages, Ina is an indicator of the flexural stiffness of the jaws. In all sizes of shark the lower jaws were stiffer than the upper and the stiffness increased in the area of the molariform teeth. The central region of the jaws, where the rami meet, support cuspidate grasping teeth and has the lowest Ina. The spotted eagle ray (Aetobatus narinari), a hard prey-crushing stingray, shows a different pattern of flexural stiffness, with the peak at the central part of the jaws where the prey is reduced between flattened tooth plates. Although the eagle ray jaws have a higher Ina than the horn shark, they are also far more heavily mineralized. When the relative amounts of mineralization are taken into account, horn sharks do better with what mineral they have than does the eagle ray. With a tight jaw joint and loose mandibular symphysis, as well as nearly opposite patterns of stiffness in the jaws, it is clear that two of the clades of hard prey specialists use very different methods for cracking the hard prey problem.

Animals↗
PubMed2004

RETIRED: Canadian contraception consensus.

This document has been archived because it contains outdated information. It should not be consulted for clinical use, but for historical research only. Please visit the journal website for the most recent guidelines.

Canada↗
PubMed2004

RETIRED: Canadian contraception consensus.

This document has been archived because it contains outdated information. It should not be consulted for clinical use, but for historical research only. Please visit the journal website for the most recent guidelines.

Canada↗
PubMed2004

SOGC clinical practice guidelines: Canadian contraception consensus.

OBJECTIVE: To provide guidelines for health-care providers on the use of contraceptive methods to prevent pregnancy and sexually transmitted diseases. OUTCOMES: Overall efficacy of cited contraceptive methods, assessing reduction in pregnancy rate, risk of infection, safety, ease of use, and side effects; the effect of cited contraceptive methods on sexual health and general well-being; and the cost and availability of cited contraceptive methods in Canada. EVIDENCE: Medline and the Cochrane Database were searched for articles in English on subjects related to contraception, sexuality, and sexual health from January 1988 to March 2003, in order to update the Report of the Consensus Committee on Contraception published in May-July 1998. Relevant Canadian Government publications and position papers from appropriate health and family planning organizations were also reviewed. VALUES: The quality of the evidence is rated using the criteria described in the Report of the Canadian Task Force on the Periodic Health Examination. Recommendations for practice are ranked according to the method described in this Report.

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PubMed2003

Neuroanatomy of flying reptiles and implications for flight, posture and behaviour.

Comparison of birds and pterosaurs, the two archosaurian flyers, sheds light on adaptation to an aerial lifestyle. The neurological basis of control holds particular interest in that flight demands on sensory integration, equilibrium, and muscular coordination are acute. Here we compare the brain and vestibular apparatus in two pterosaurs based on high-resolution computed tomographic (CT) scans from which we constructed digital endocasts. Although general neural organization resembles birds, pterosaurs had smaller brains relative to body mass than do birds. This difference probably has more to do with phylogeny than flight, in that birds evolved from nonavian theropods that had already established trends for greater encephalization. Orientation of the osseous labyrinth relative to the long axis of the skull was different in these two pterosaur species, suggesting very different head postures and reflecting differing behaviours. Their enlarged semicircular canals reflect a highly refined organ of equilibrium, which is concordant with pterosaurs being visually based, aerial predators. Their enormous cerebellar floccular lobes may suggest neural integration of extensive sensory information from the wing, further enhancing eye- and neck-based reflex mechanisms for stabilizing gaze.

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