Efficacy of embryo transfer in lactating dairy cows during summer using fresh or vitrified embryos produced in vitro with sex-sorted semen.

The objective was to determine whether transfer of fresh or vitrified embryos produced in vitro with sex-sorted semen improves pregnancy and calving rates during summer in lactating dairy cows compared with artificial insemination (AI). Lactating dairy cows (n=722) were enrolled during summer months at 2 commercial dairies in Central Texas and randomly assigned to 1 of 3 treatments: AI with conventional semen (n=227), embryo transfer-vitrified (ET-V; n=279) or embryo transfer-fresh (ET-F; n=216). Embryos were produced in vitro using sex-sorted semen and with Block-Bonilla-Hansen-7 culture medium. For vitrification, grade 1 expanded blastocysts were harvested on d 7 after fertilization and vitrified using the open-pulled straw method. Fresh embryos were grade 1 blastocysts and expanded blastocysts harvested on d 7 after fertilization. Cows were submitted to the Ovsynch56 protocol: d -10 GnRH, d -3 PGF(2α), d -1 GnRH and d 0 timed AI; or Select Synch protocol: d -9 GnRH, d -2 PGF(2α), and AI following detected estrus (day of AI=d 0). On d 7, all cows were examined for presence of a corpus luteum (CL). A vitrified or fresh embryo was transferred to cows with CL in ET-V and ET-F groups. Cows were considered synchronized if progesterone was <1ng/mL on d 0 and a CL was present on d 7. At d 40±7 of gestation, the percentage of cows pregnant was greater for the ET-F compared with the ET-V and AI groups among all cows (42.1 vs. 29.3 and 18.3%, respectively) and synchronized cows (45.5 vs. 31.6 and 24.8%, respectively). Also, the percentage of cows pregnant was greater for the ET-V than the AI group among all cows and tended to be greater among synchronized cows. At d 97±7 of gestation, the percentage of cows pregnant among all cows was greater for ET-F and ET-V groups than for the AI group (36.4 and 25.7 vs. 17.0%, respectively) and the percentage for the ET-F group was greater than for the ET-V group. Among synchronized cows, the percentage of cows pregnant was significantly increased for the ET-F group than for ET-V and AI groups (39.4 vs. 27.8 and 23.1%, respectively) and no difference was found between ET-V and AI groups. No effect of treatment on embryo loss was observed. The percentage of cows with live births was significantly increased for the ET-F than for ET-V and AI groups among all cows (27.5 vs. 17.1 and 14.6%, respectively) and synchronized cows (29.9 vs. 18.5 and 20.0%, respectively). The percentage of cows giving birth to a live heifer was significantly increased for the ET-F and ET-V groups compared with the AI group among all cows (79.1 and 72.5 vs. 50.0%, respectively) and synchronized cows (79.1 and 72.5 vs. 50.0%, respectively). No difference existed between ET-F and ET-V groups for percent live heifer births but both were greater than for the AI group. The transfer of fresh embryos produced in vitro using sex-sorted semen to lactating dairy cows during summer can effectively increase the percentage of cows that establish pregnancy and also the percentage of cows that give birth to a live heifer compared with percentages from AI with conventional semen.

Chemical forms and extractability of iron in sediments of three contrasting lakes of China and UK.

Iron is a limiting factor for the eutrophication of lakes, especially those lakes that are enriched with phosphorus. Extractability of iron in sediments of West Lake and Taihu Lake in China and Lower Lough Erne in Northern Ireland of UK was comparatively investigated on the basis of analysing chemical forms of iron using different extractants. It was shown that extractable iron in sediments of the lakes was greatly different using various extractants. Reactive iron or easily released iron such as "active" iron oxides, total free iron oxide and water-soluble iron was not high, only accounting for 0.01%-0.15% of total iron. The efficiency of the extractants for exchangeable iron was decreased in the sequence 0.1 mol/L HCl >> DTPA + TEA mixed solution > 1 mol/L NH4OAc > 0.5 mol/L MgCl2 = 0.5 mol/L CaCl2. It seems that the complexion of iron by organic matter was not strong because the concentration of organically bound iron was significantly lower than the concentration it was forecasted. Extractable iron is not entirely consistent with or dependent on total iron in lake sediments. To a certain extent, phosphate can inhibit the release of iron in sediments of the lakes. The selection of extractants is thus the first key step to evaluate bioavailability of iron in lake sediments.

Guatemalan women's paper making co-op.

PIP: Founded in 1992, is an independent grassroots organization whose goal is to assist community development, health, education, clean water and income generation. The Q'eqchi' Maya Indians constitute the fourth largest indigenous group located on the banks of Rio Dulce, in the eastern rainforest of Guatemala. Project Ak'Tenamit helped the Q'eqchi' people revive their ancient art of paper making as a viable and self-sustainable source of income. As the material used by the ancient Maya--cork husk and banana stalks--are still abundant, it was decided that this art could be successfully re-introduced. With papermaking, the Q'eqchi women were able to earn money from their own production without even compromising their respective households. Ak'Tenamit was responsible for the distribution of paper making products in stores throughout Guatemala. Although there are still many obstacles confronting these women, the paper making cooperative provides employment opportunities and is indeed a great help to them. They produce a total of 15 different products including bowls, cards, and bookmarks.^ieng

The effect of amalgam overhangs on alveolar bone height as a function of patient age and overhang width.

The purpose of this study was to compare the effects of amalgam restorations with and without overhangs on alveolar bone loss via digitized radiographs for subjects of varying ages and overhang widths. The first phase of this study compared the alveolar bone loss among teeth with clinically acceptable two-surface amalgam restorations with a control surface on the same tooth. The second phase was similar to the first phase with the exception that it compared defective amalgam restorations (those containing amalgam overhanging approximal margins) with the control surface on the same tooth. The collected data showed a significant loss of alveolar bone as a result of amalgam overhang presence (P < 0.02). However, overhang width and patient age did not affect the significance of the detrimental effects of the amalgam overhangs. Overall alveolar bone height was seen to decrease with patient age, independent of amalgam restorations. Digital radiography was seen to be an accurate method for evaluating alveolar bone height changes due to the local environment created by overhanging amalgam margins.

The prevalence and effect of alcohol and drug abuse on cohort-matched critically injured patients.

A prospective study was undertaken at a Level I trauma center to evaluate the prevalence of substance use among victims of major trauma, along with the impact on clinical outcome. Five hundred sixteen patients had urine toxicology and blood alcohol screens performed and correlated with pattern and severity of injury, hospital course, and outcome. Three hundred seventy-one patients (71%) screened positive for alcohol or drugs, or both. Fifty-two per cent had positive alcohol screens, and 42 per cent had positive drug screens (cocaine and opiates represented 91% of positive drug screens). Univariate analysis revealed patterns of alcohol/drug use varied among subgroups according to demographics (less use among patients older than 55 years, females and Asians; more drug use in blacks; more alcohol use in Hispanics), mechanism of injury (non-use in blunt trauma patients and use of both in penetrating trauma patients) and body region injured (non-use in head-injured patients). Septic complications and mortality were more correlative with severity of injury, but not with use or non-use of alcohol or drugs. We conclude that alcohol and drug use remains a major comorbid factor in major trauma, and that injury prevention efforts should include a strong focus on counseling regarding these lifestyle choices.

Complications and nonclosure rates of fasciotomy for trauma and related risk factors.

The objective of this study was to identify risk factors for the development of complications and unsatisfactory skin closure following fasciotomy for trauma. Risk factors included in the study are prolonged time from injury to fasciotomy, type of fasciotomy, site of injury, and kind of underlying injury. The study was a retrospective analysis of 100 consecutive fasciotomies done for trauma over a period of 38 months (December 1991 to January 1995) in a "level I" trauma center at a university-affiliated county teaching hospital. Ninety-four patients were eligible for analysis, 29 of whom (31%) developed complications at the fasciotomy site. The risk was increased for lower extremity versus upper extremity (34.3% versus 20.8%), prophylactic versus therapeutic (42.0% versus 24.6%), late (>8 hours) versus early (37% versus 25%), and vascular versus musculoskeletal (38.8% versus 22.2%) trauma cases. The same risk factors negatively influenced the ability to close the skin primarily. The four subgroups defined by vascular/nonvascular injury and upper/lower extremity site had significantly different nonclosure rates (p = 0.043). The rate was highest among the vascular/lower extremity group (60.5%) and lowest among the nonvascular/upper extremity group (15.4%). We concluded that fasciotomies in lower extremities, the presence of underlying vascular injuries, fasciotomies performed prophylactically, and a time between the injury and fasciotomy of more than 8 hours are associated with an increased risk for local complications. The same factors are associated with an increased need for skin grafting the wound.

An evolutionary concept analysis of mentoring in nursing.

Despite widespread evidence of the concept of mentoring in nursing, it has been largely undefined, borrowed from other disciplines, viewed as static, and/or confused with related terms. Building on the work of Yoder and using a literature-based method developed by Rodgers, an evolutionary concept analysis is presented to provide an understanding of the meaning of mentoring in nursing, its current status, and the conceptual clarity necessary for additional systematic and rigorous inquiry. A random sample of 82 research abstracts and journal articles, representing 26 per cent of the total population of literature, was used to extract six essential attributes of the concept: a teaching-learning process, a reciprocal role, a career development relationship, a knowledge or competence differential between participants, a duration of several years, and a resonating phenomenon. These attributes form the theoretical definition of mentoring in nursing. Antecedents, consequences, related concepts, and empirical referents are presented. A model case, encompassing all of the critical attributes, depicts the Investigators' mentoring experience. Major changes in mentoring are viewed within the context of nursing as a learned profession, a legitimate academic enterprise, and a clinical science. Implications for further development are posed to further mentoring as a process for the socialization of nurse scholars and scientists and the proliferation of a body of professional knowledge.

Penetrating cardiac injuries.

Penetrating cardiac injuries pose a tremendous challenge to any trauma surgeon. Time, sound judgment, aggressive intervention, and surgical technique are the most important factors contributing to positive outcomes. This article extensively reviews the history, surgical management, and techniques needed to deal with these critical injuries. This year commemorates the one hundredth anniversary of the first successful repair of a cardiac injury.

End-of-life family decision-making from disclosure of HIV through bereavement.

End-of-life decision-making is conceptualized as the foreground against the background of a family, transitional model of illness with the human immunodeficiency virus (HIV). Both foreground and background represent new knowledge and theory development emerging from six research studies over a 7-year period. The research was phenomenological, longitudinal, ethnographic, descriptive survey, narrative, and grounded using the constant comparative method. In all, 100 families were studied in their home settings in the District of Columbia and 29 states across the United States. Throughout the transitional process from disclosure of HIV through bereavement, families engaged in end-of-life decision-making. Their decision-making style was primarily cognitive or primarily emotional or somewhere in between. Families using a cognitive style of decision-making were less disrupted and more able to surmount hurdles and move toward goals. Exemplars from 23 families illustrated family decision-making and components of the transitional, family model.