The maize tha4 gene functions in sec-independent protein transport in chloroplasts and is related to hcf106, tatA, and tatB.

Proteins are translocated across the chloroplast thylakoid membrane by a variety of mechanisms. Some proteins engage a translocation machinery that is derived from the bacterial Sec export system and require an interaction with a chloroplast-localized SecA homologue. Other proteins engage a machinery that is SecA-independent, but requires a transmembrane pH gradient. Recently, a counterpart to this Delta pH mechanism was discovered in bacteria. Genetic studies revealed that one maize protein involved in this mechanism, HCF106, is related in both structure and function to the bacterial tatA and tatB gene products. We describe here the mutant phenotype and molecular cloning of a second maize gene that functions in the Delta pH mechanism. This gene, thylakoid assembly 4 (tha4), is required specifically for the translocation of proteins that engage the Delta pH pathway. The sequence of the tha4 gene product resembles those of the maize hcf106 gene and the bacterial tatA and tatB genes. Sequence comparisons suggest that tha4 more closely resembles tatA, and hcf106 more closely resembles tatB. These findings support the notion that this sec-independent translocation mechanism has been highly conserved during the evolution of eucaryotic organelles from bacterial endosymbionts.

The Mouse Genome Database (MGD): from genes to mice--a community resource for mouse biology.

The Mouse Genome Database (MGD) forms the core of the Mouse Genome Informatics (MGI) system (http://www.informatics.jax.org), a model organism database resource for the laboratory mouse. MGD provides essential integration of experimental knowledge for the mouse system with information annotated from both literature and online sources. MGD curates and presents consensus and experimental data representations of genotype (sequence) through phenotype information, including highly detailed reports about genes and gene products. Primary foci of integration are through representations of relationships among genes, sequences and phenotypes. MGD collaborates with other bioinformatics groups to curate a definitive set of information about the laboratory mouse and to build and implement the data and semantic standards that are essential for comparative genome analysis. Recent improvements in MGD discussed here include the enhancement of phenotype resources, the re-development of the International Mouse Strain Resource, IMSR, the update of mammalian orthology datasets and the electronic publication of classic books in mouse genetics.

A two-color acid-free cartilage and bone stain for zebrafish larvae.

Traditionally, cartilage is stained by alcian blue using acidic conditions to differentiate tissue staining. The acidic conditions are problematic when one wishes to stain the same specimen for mineralized bone with alizarin red, because acid demineralizes bone, which negatively affects bone staining. We have developed an acid-free method to stain cartilage and bone simultaneously in zebrafish larvae. This method has the additional advantage that PCR genotyping of stained specimens is possible.

The cognitive effects of recombinant interleukin-2 (rIL-2) therapy: a controlled clinical trial using computerised assessments.

It has been suggested that patients undergoing treatment with recombinant interleukin-2 (rIL-2) may develop cognitive impairment. To evaluate these effects, 17 patients with advanced colorectal cancer took part in a randomised, parallel group study of rIL-2 with chemotherapy (5-fluorouracil and leucovorin) and chemotherapy alone. Assessments were carried out daily whilst patients were in hospital and regularly between cycles of treatment using state-of-the-art computerised cognitive assessment, as well as traditional psychometric tests. Rigorous discontinuation criteria were applied to ensure that the effect of time-related variables did not influence the results. One patient developed repeated transient psychotic episodes associated with rIL-2 infusions and another regularly became confused. Computerised cognitive assessments revealed that immunochemotherapy produced significant impairment in various tasks, especially reaction time, picture recognition and vigilance. These effects were not due to sleep deprivation or pyrexia. For most patients, cognitive functioning was restored to the baseline level within 10 days following the cessation of rIL-2. In conclusion, during infusions of rIL-2, some patients experience severe confusion and amnesia which resembles some of the major cognitive impairments associated with dementias such as Alzheimer's disease. Computerised cognitive assessment using the Cognitive Drug Research system provides a feasible, sensitive and reliable method of evaluating cognitive changes in patients with cancer. It could usefully be included in quality of life assessments in clinical trials where treatment-related cognitive changes need to be evaluated.

Psychological factors can predict the response to primary chemotherapy in patients with locally advanced breast cancer.

This study evaluated the possible value of psychological variables in predicting clinical and pathological response to primary chemotherapy. 96 women with newly diagnosed large, or locally advanced, breast cancer (T2 > 4 cm, T3, T4, N2 and M0) participated in a prospective, randomised trial to evaluate the effects of relaxation training with guided imagery and L-arginine on response to primary chemotherapy. Before the first of six cycles of primary chemotherapy, women were assessed using the Hospital Anxiety and Depression Scale (HADS) and the Eysenck Personality Questionnaire (EPQ). The primary outcomes were clinical response (evaluated using standard International Union Against Cancer (UICC) criteria) and pathological response (graded by means of a previously published 5-point scale) following primary chemotherapy. Stepwise linear regressions were used to estimate the predictive value of age, menopausal status, clinical nodal status, tumour size at diagnosis, oestrogen receptor status, dietary supplementation (L-arginine versus placebo), personality (EPQ-L scores), mood (HADS scores) and a psychological intervention. HADS depression score was a significant independent predictor of pathological response to chemotherapy. HADS anxiety score was a significant independent predictor of clinical response. Because the original tumour size before chemotherapy (also a significant predictor of clinical and pathological responses) was taken into account in the analyses, the results cannot be explained in terms of psychobiological factors related to tumour size. This study supports the importance of psychological factors as independent predictors of response to primary chemotherapy in patients with breast cancer. If they can be replicated, these findings have major implications for the management of women with breast cancer. Psychological factors need to be assessed and evaluated in future trials of chemotherapy.

Structural changes vary along individual arterioles in deoxycorticosterone acetate hypertensive rats.

The variability of structural changes along individual arterioles in deoxycorticosterone acetate (DOCA) hypertensive rats was measured by coefficients of variation of: (a) serial lumen diameters along microfil casts of individual mesenteric arterioles; and (b) wall and lumen indices in serial histological cross-sections along individual renal arterioles. The mean lumen diameter of third-order mesenteric arterioles decreased with increasing duration of hypertension. There was increased variability of lumen diameter along lengths of DOCA arterioles, the coefficient of variation at 10 weeks DOCA treatment being 20.2 +/- 0.6% compared to 9.2 +/- 0.2% in controls (P less than 0.001). Medial area to internal elastic lamina (IEL) radius ratio of renal arterioles was increased in DOCA rats compared with control rats (P less than 0.025) and its variability along individual arterioles expressed as the coefficient of variation was 31.70 +/- 3.87% in DOCA rats compared with 15.29 +/- 1.72% in controls (P less than 0.005). The observed increase in variability of lumen diameter and medial area along short lengths of individual arterioles in DOCA hypertensive rats indicates that hypertensive structural changes are probably not directly related to local blood pressure. We suggest that irregular functional vasoconstriction in hypertensive rats could account for this distribution of structural changes.

Lower intraoperative flap complication rate with the Hansatome microkeratome compared to the Automated Corneal Shaper.

PURPOSE: The purpose of this study was to retrospectively compare the incidence of intraoperative flap complications, such as partial flaps, donut-shaped flaps, central corneal cuts, and complete caps with the Hansatome and Automated Corneal Shaper (ACS) microkeratomes. METHODS: All laser in situ keratomileusis (LASIK) procedures performed by a single surgeon with the Hansatome or Automated Corneal Shaper in which intraocular pressure was verified with a pneumotonometer were reviewed. RESULTS: A total of 90 eyes had LASIK with the ACS microkeratome. Six of the ACS eyes (6.7%) had intraoperative flap complications (4 partial flaps, 1 donut-shaped flap, 0 central corneal cuts, 1 complete cap). Partial flaps and donut-shaped flaps were replaced without laser application and the procedure repeated 2 to 3 months later. Two of these eyes lost 2 lines and one lost 1 line of spectacle-corrected visual acuity at 6 months after repeat LASIK. The eye with the donut-shaped flap was treated with transepithelial photorefractive keratectomy (PRK) and had no change in spectacle-corrected visual acuity at 6 months after PRK. The eye with the complete cap had no change in spectacle-corrected visual acuity after laser ablation. Five hundred ninety-eight (598) eyes had LASIK with the Hansatome microkeratome. Two of the Hansatome eyes (0.3%) had a flap complication (1 partial flap and 1 donut-shaped flap). The first eye retained spectacle-corrected visual acuity at 6 months after repeat LASIK. The second eye had transepithelial PRK to eliminate the donut shaped flap with no loss of spectacle-corrected visual acuity at 6 months after surgery. The difference in flap complications between the two procedures was statistically significant (P < .01). There were no flap displacements following surgery in either group. CONCLUSION: Intraoperative flap complications are less likely to occur with the Hansatome microkeratome than with the ACS microkeratome.

Incidence and prevention of epithelial growth within the interface after laser in situ keratomileusis.

PURPOSE: To analyze the incidence of epithelial growth within the interface after laser in situ keratomileusis (LASIK) and describe a technique that may prevent its occurrence. METHODS: Results were reviewed for all LASIK procedures performed by two surgeons using identical surgical technique with either the Automated Corneal Shaper or Hansatome microkeratome. After laser ablation, the bed and posterior surface of the flap were irrigated with 0.2 microM filtered basic salt solution, and the surfaces were swept with lint-free sponges to clear the interface of epithelial and other debris. An aspirating lid speculum connected to suction was used to evacuate irrigation fluid and debris from the field. After the flap was smoothed into position, a bandage contact lens was used for the first day after surgery to prevent lifting of the flap edge during blinking. RESULTS: Seven hundred eighty-three eyes of 419 patients had primary LASIK, and 108 eyes had LASIK reoperation. Three eyes developed epithelial growth within the interface, with a minimum of 3 months of follow-up. The interface opacity appeared within 1 month of surgery in all three eyes. Two epithelial nests were small (1.0 and 1.5 mm in diameter, respectively) and did not increase in size on subsequent visits. Neither peripheral epithelial nest affected best-corrected visual acuity or caused any other sequelae. One ingrowth occurred early postoperatively in a case with a donut-shaped flap and was eliminated by transepithelial photorefractive keratectomy (PRK). CONCLUSION: Irrigating, wiping the stromal interface with sponges. aspirating irrigation fluid and debris with a suctioning lid speculum, and use of a bandage contact lens for the first day after surgery during LASIK and LASIK enhancement may markedly reduce the incidence of epithelial growth within the interface.

Recovery of uncorrected visual acuity after laser in situ keratomileusis or photorefractive keratectomy for low myopia.

PURPOSE: To compare uncorrected visual acuity and refractive error in patients undergoing photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) between 1 week and 6 months after surgery. METHODS: All eyes underwent PRK or LASIK with the VisX StarS2 excimer laser. We retrospectively analyzed data from 77 random eyes of 77 patients in the PRK group and 76 eyes of 76 patients in the LASIK group. All eyes had a low myopic refractive error (spherical equivalent range, -0.88 diopters (D) to -5.13 D; mean PRK. -2.8 +/- 0.20 D: LASIK, -2.5 +/- 0.22 D). Uncorrected visual acuity and manifest refractive error were evaluated 1 week, 1 month, and 6 months after surgery. RESULTS: Each eye undergoing PRK was paired with an eye undergoing LASIK for a similar level of spherical equivalent. Mean uncorrected visual acuity after 1 week was 0.85 +/- 0.06 (20/25, logMAR 0.12 +/- 0.04) for the PRK group and 1.01 +/- 0.06 (20/20, logMAR 0.01 +/- 0.03) for the LASIK group (p < 0.001). Mean spherical equivalent after 1 week was 0.23 +/- 0.12 D for the PRK group and -0.02 +/- 0.07 D for the LASIK group (p = 0.02). Mean uncorrected visual acuity after 1 month was 1.03 +/- 0.05 (20/20, logMAR 0.02 +/- 0.03) for the PRK group and 1.05 +/- 0.05 (20/20. -0.02 +/- 0.03) for the LASIK group (p = 0.16). Mean spherical equivalent after I month was 0.19 +/- 0.10 D for the PRK group and -0.02 +/- 0.09 D for the LASIK group. This difference was statistically significant (p = 0.02), but was unlikely to be clinically significant. Mean uncorrected visual acuity after 6 months was 1.05 +/- 0.06 (20/20, logMAR -0.01 +/- 0.03) for the PRK group and 1.06 +/- 0.05 (20/20, logMAR -0.14 +/- 0.03) for the LASIK group (p = 0.41). Mean spherical equivalent after 6 months was 0.02 +/- 0.08 D for the PRK group and 0.00 +/- 0.08 D for the LASIK group (p = 0.35). CONCLUSION: Uncorrected visual acuity 1 week after surgery is significantly better in eyes undergoing LASIK than in eyes undergoing PRK. Both procedures provide functional vision by 1 week after surgery. The difference does not relate to refractive error, which was similar between the two groups, but to differences in healing of the epithelium. By 1 month after surgery, there is no difference in mean uncorrected visual acuity between eyes that undergo PRK or LASIK for low myopia.

High risk behaviours related to maternal and child health.

BACKGROUND: The excessive high maternal and perinatal mortality and morbidity figures characteristic of our community could be linked with maternal high-risk behaviours during pregnancy, delivery and postnatal periods. This cross-sectional questionnaire study assessed the prevalence of these behaviours among mothers in Ibadan. METHODS: Consecutive mothers attending infant welfare clinics of selected formal health facilities in Ibadan within 6 weeks of delivery were interviewed with a questionnaire. RESULTS: Of the 500 women interviewed, only 2.4% did not receive any antenatal care, 87.7% commenced care after first semester (57.2% and 30.5% in the second and third trimesters respectively). Twenty-five percent, 7.5% and 4.8% received no malaria prophylaxis, no tetanus immunisation, and iron preparations during pregnancy respectively. Seventeen percent (16.9%) received incomplete tetanus immunisation. Thirty percent (30%) of the women delivered out of formal health facilities, in church-based maternity and at home. While 91.4% received group breastfeeding counselling, 72% received group counselling specifically on exclusive breastfeeding. Eighty-four percent of the babies were not exclusively breast-fed, with 62.9%, 26.8% and 4.6% receiving supplementation with water, herbal preparations and artificial milk respectively. Sixty-seven percent of the babies received first immunisation after the first week of delivery. Prevalence of high risk behaviours related to maternal and child health care were not significantly different among the women utilising formal health facilities irrespective of the level, but were significantly higher among women who did not. CONCLUSION: A high prevalence of high-risk behaviours during pregnancy, delivery and postnatal periods, despite the availability of services, has been highlighted. There is a need to promote optimal utilization of existing services. There may be a need for quality assurance of these services.

Conformity in the Asch task as a function of age.

The social conformity paradigm of Asch (1956) was replicated to investigate the relationship between age and conformist behavior. One hundred ten Australian school children and adolescents between 3 and 17 years of age participated in the study. Each participant was placed in the position of being a minority of 1 against a wrong but unanimous majority of 3. The results indicate that conformity decreases with age in perceptually unambiguous tasks. Conflicting evidence from earlier studies can be attributed to task ambiguity in those studies.

Height and weight measurements of Ibadan school children.

Height and weight measurements were carried out on three groups of Nigerian primary school children aged 6-12 years, in and around Ibadan. A total of 1,192 children was examined from three social classes as follows: (1) the educated elite group (n = 444); (2) the urban low socio-economic group (n = 366), and (3) the rural village group (n = 382). The school children from the educated elite group had the highest mean height and weight values while the school children from the rural group had the lowest values and the urban low socio-economic came in between the two. In the children of the educated elite class, mean heights and weights were higher than those of the international reference population (though not significantly so) only at ages 6-9 years. Malnutrition as indicated by wasting and stunting was prevalent among both rural and urban low socio-economic school children. The prevalence of wasting was 75.9% among the rural school children, while it was 62.5% among the urban low socio-economic children. The prevalence of stunting was 79.1% among the rural school children, while it was 62.9% among the urban low socio-economic school children. Neither stunting nor wasting was observed among the children of the elite educated group. This study has demonstrated that there has been no change with time in the pattern of differences of height and weight with respect to school children of various social classes.

Extraversion and exercise addiction.

Extraversion has been suggested as a factor associated with addiction. This claim was tested in relation to exercise addiction. Twelve exercise addicts were compared with 12 nonaddicted individuals who were committed to regular exercise and with 12 nonexercising individuals drawn from the same student population. Addicted exercisers did not differ from nonaddicted exercisers in extraversion, although exercisers as a group were more extraverted than nonexercisers. The results are interpreted as evidence against the claim that extraversion is a component of the addictive personality profile.

The marriage tax and the rate and timing of marriage.

"The effect of the differential tax treatment of married and unmarried couples, the so-called marriage tax, on the rate and timing of [U.S.] marriages is analyzed. Using time-series data, we study the effect of the marriage tax on the fraction of unmarried women over the age of 15 years who marry in each year. We find no effect. We also investigate whether couples shift the timing of their marriage from the end of one year to the beginning of the next year in response to an increase in the marriage tax. We find empirical support for this behavior."

Craniofacial malformations: intrinsic vs extrinsic neural crest cell defects in Treacher Collins and 22q11 deletion syndromes.

The craniofacial complex is anatomically the most sophisticated part of the body. It houses all the major sensory organ systems and its origins are synonymous with vertebrate evolution. Of fundamental importance to craniofacial development is a specialized population of stem and progenitor cells, known as the neural crest, which generate the majority of the bone, cartilage, connective and peripheral nerve tissue in the head. Approximately one third of all congenital abnormalities exhibit craniofacial malformations and consequently, most craniofacial anomalies are considered to arise through primary defects in neural crest cell development. Recent advances however, have challenged this classical dogma, underscoring the influence of tissues with which the neural crest cells interact as the primary origin of patterning defects in craniofacial morphogenesis. In this review we discuss these neural crest cell interactions with mesoderm, endoderm and ectoderm in the head in the context of a better understanding of craniofacial malformations such as in Treacher Collins and 22q11 deletion syndromes.

Irrational thinking among slot machine players.

According to the cognitive perspective on gambling, regular gamblers persist in trying to win money at gambling because they hold a set of false beliefs about the nature of gambling, the likelihood of winning, and their own expertise. In order to investigate this claim, twenty seven university students were recruited who played one of three types of games at least twice a week: slot machines, video draw poker, and video amusement games. Subjects played their preferred machines on site (clubs, hotels and amusement arcades) first for at least thirty minutes and then the other two games for a minimum of twenty minutes each. During play, each subject spoke aloud into a microphone describing what he or she was doing or thinking about in the game. It was hypothesised that slot machine players would verbalise more irrational thinking than video poker or video amusement players and that slot machines would elicit more irrational thinking than video poker or video amusement machines. Most importantly, it was hypothesised that slot machine players would exhibit relatively greater amounts of irrational thinking when playing their preferred game. The data supported all three hypotheses. Out of all of the statements made by slot machine players when playing slot machines, 38% were categorised irrational. Furthermore, 80% of the strategic statements made by slot machine players while playing slot machines were categorised as irrational. These results are consistent with earlier work which showed high levels of irrational thinking in artificial gambling games. Together, the results provide support for a cognitive view of the origins of gambling problems.

What's your specialty, Doc? Perioperative nursing.

Perioperative nurses who are contemplating the pursuit of a doctoral degree in nursing need information about the current status and characteristics of doctoral education to make informed decisions. This article addresses questions both philosophic and pragmatic that should be addressed by prospective students. Information sources are identified for assistance with making the selection from the 75 plus programs that offer a nursing doctorate nationwide. Suggested sources include professional organizations as well as current students, faculty, and alumni. Determinations should be based on academic information, such as similarities and differences in degrees awarded; the program of studies leading to the degree; admission and progression standards; research interest of the student relative to identified focus and expertise of program faculty, dissertation process, and university and nursing education resources and services, including financial and technological support. Attainment of the doctorate is presented as an enriching experience that prepares nurses for leadership in both education and health care as clinicians, educators, and administrators. Particular attention should be paid to selecting programs that compare favorably with the published American Association of Colleges of Nursing quality indicators for doctoral programs. There must be strong support in the program from both faculty mentors and peer colleagues, reflective of a community of scholars, pursuing not only individual but also collective wisdom, whereas engaging an individual's mind and soul in the pursuit of new knowledge and skills in an atmosphere of mutual trust and respect.

Model for superconductivity in ferromagnetic ZrZn2.

We propose that superconductivity in the ferromagnetic state of ZrZn2 is stabilized by an exchange-type interaction between the magnetic moments of triplet-state Cooper pairs and the ferromagnetic magnetization density. This explains why superconductivity occurs in the ferromagnetic state only, and why it persists deep into the ferromagnetic state. The model of this article also yields a particular order parameter symmetry, which is a prediction that can be checked experimentally.