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PubMed2004

Developing mouse Sertoli cells in vitro: effects on developing ovaries in co-culture and production of anti-Müllerian hormone.

Previous work in our laboratory showed that pre-Sertoli cells adopt an epithelial phenotype when cultured in the presence of reconstituted basement membrane (RBM), and so cultures were established with and without this substrate. Biological activity of isolated developing mouse Sertoli cells maintained in vitro was assessed in the current study by utilising a co-culture approach, to determine whether the cells were capable of affecting ovarian differentiation. Developing Sertoli cells isolated at embryonic day (E) 12.5 exerted a deleterious effect on E12.5 ovaries in co-culture, inducing a loss of germ cells. However, when cells were isolated a day later and co-cultured with E13.5 ovaries (after entry to meiosis has begun), germ cells survived and showed evidence of meiosis, although ovigerous cords in co-cultures were masculinized compared to those of control cultured ovaries. Thus, both stages examined showed biological effects; cultured pre-Sertoli cells explanted at E12.5 showed a negative effect on female germ cells, whereas those explanted at E13.5 masculinized ovigerous cords. The functional status of isolated developing mouse Sertoli cells in vitro was further assessed by immunocytochemistry to investigate the expression of anti-Müllerian hormone, an early product of pre-Sertoli cells. Positive immunostaining was seen in developing Sertoli cells in vitro, particularly where cells had been explanted to an RBM substrate, demonstrating that good epithelial morphology is associated with improved function. Our culture system is therefore well suited for investigating factors produced by developing Sertoli cells, their role in influencing testicular morphogenesis and their potential to perturb ovarian differentiation. We believe that this in vitro approach provides a more physiological assessment compared with the knockout mouse model, where global effects of genes with housekeeping functions can compromise overall development.

Animals↗

PubMed2005

The Eating Disorders Section of the Development and Well-Being Assessment (DAWBA): development and validation.

OBJECTIVE: Development and validation of the Eating Disorders Section of the Development and Well-Being Assessment (DAWBA). It is a package of questionnaires, interviews and evaluation techniques, designed to generate DSM-IV and ICD-10 based diagnoses of anorexia, bulimia nervosa and the respective partial syndromes in epidemiological studies, in subjects who are 7 to 17 years old. The parents are interviewed in all cases, as are young people aged 11 or more. METHODS: 174 girls, divided into three groups, were assessed with the Eating Disorders Section of the Development and Well-Being Assessment: 48 with eating disorders, 55 clinical controls (with depression, obsessive-compulsive disorder or gastrointestinal disease) and 71 community controls. The sensitivity, specificity and predictive values of the assessment were investigated by comparing the Development and Well-Being Assessment diagnoses with independent psychiatric diagnoses. The test-retest reliability was investigated by reapplying the measure on 55 subjects after 2 or 3 weeks. RESULTS: For the detection of any DSM-IV and ICD-10 eating disorder, the final Development and Well-Being Assessment diagnosis had a sensitivity of 100%, specificity of 94%, positive predictive value of 88%, and a negative predictive value of 100%; there was 95% agreement between the initial and repeat diagnoses (a kappa of 0.81). CONCLUSION: The Eating Disorders Section of the Development and Well-Being Assessment has suitable psychometric properties for use in clinical and epidemiological studies.

Adolescent↗

PubMed1995

How the developing septo-preoptic medical basal hypothalamus stimulates the development of placode-derived LHRH neurons.

We examined the effects of the developing cerebral cortex (CC) and septo-preoptic medial basal hypothalamus (S-MBH) on the development of LHRH neurons in vitro. The serum-free basal culture medium (BCM) was supplemented with CC or S-MBH extracts prepared from 18.5-day-old embryos or from 2-day-old newborns, and the olfactory placode (NAP) of 12-day-old embryos was cultured. The migration of LHRH neurons was found on Day 3 in the cultures supplemented with the embryonic S-MBH extract (Group 3), where the cell development proceeded showing a numerical increase of the cells and the elongation of neurites. In cultures supplemented with the newborn S-MBH extract (Group 5), the cell development was less intensive in comparison with that of Group 3, while in cultures which had no brain extracts (Group 1), the neurons failed to survive a long term culture. The effects of the CC were less than of S-MBH extracts. Analysis of the protein composition of the extracts by electrophoretic and immunoblotting examinations demonstrated a protein spot of 70-kD in the embryonic S-MBH extract. Because the protein spot was identified to be alpha-fetoprotein (AFP), we further examined the effects of AFP. When the anti-AFP immunoglobulin was added to the Group 3 culture, the stimulative effects of the embryonal extract were inhibited, and the addition of AFP to Group 1 cultures did not show stimulative effects. We conclude that the developing S-MBH, the migrating target of LHRH neurons, contains some essential factors for the development of LHRH neurons, but further analysis is needed to determine the chemical natures of these factors.

Animals↗

PubMed1976

The effects of experimental unilateral anotia on skull development in the chick embryo. III. Chondrocranial development in anotic embryos of 7-20 days of incubation.

The study of the development of of the chondrocranium in chick embryos with unilateral (right-sided) anotia revealed the following main characteristics. 1. The median axes of the chordal and the prechordal part of the cranial base are not in a straight line but show a deviation toward the right side. The angle between the two axes has its vertex in the region of the foramen hypophyseos. 2. The metotic cartilage and the foramina of the IXth and Xth cranial nerves are normal in position. 3. The tectum synoticum develops later and to a lesser extent than normal. 4. Between the basal plate, the metotic cartilage, the occipital arch and the supracapsular cartilage a foramen is formed which, later in development, is closed by outgrowths of the metotic cartilage and the basal plate. 5. The "optic area" shows a practically normal appearance which indicates that the cartilaginous ventral wall of the lagenal capsule is of basal plate origin. 6. The pro-otic process develops practically normal and, hence, is independent of the ear capsule. 7. The quadrate cartilage and the right lower jaw are displaced ventro-posteriorward. The earliest development of the perichondral bones shows some particularities which are closely correlated with the development of the various cartilaginous structures.

Animals↗

PubMed2005

[A physiological development time-based simulation model for cotton development stages and square- and boll formation].

In this study, three cotton varieties (CRI 36, CRI 35 and CRI 41) were planted in Nanjing, Anyang, Baoding and Shihezi, respectively, in 2002, and the dynamic relationships between their development and environmental factors were analyzed. Based on this, a simulation model for cotton development stages and square-and boll development was built in terms of physiological development time (PDT). In calculating relative thermal effectiveness, the effect of diurnal temperature differences in different regions on cotton development was incorporated, and the enhancement of plastic mulching on air temperature was quantified. To simulate development stages, the initial fruiting node index (IFIN), sunlight duration factor (FSH), and solar radiation index on fruiting branch (IFBR) were introduced, besides earliness factor of a given genotype. The validation of the model with the data obtained from different years, ecological zones, genotypes, and cultivation practices indicated a high goodness of fitness between the simulated results and observed values. The root mean square error (RMSE) between simulated and observed days from sowing to emergence, emergence to squaring, anthesis to boll opening, and sowing to boll opening was 0.9, 2.2, 1.7, and 2.1 d, respectively, with a mean of 2.1 d, and in all plant sites, the RMSE between simulated and observed days from squaring to boll opening was 1.8-3.7 d, and that from squaring to opening was 4.6-5.8 d.

Gossypium↗

PubMed2005

The development of the model for recognition of prior learning for nurses in South Africa: development of RPL guidelines by the policy makers and stakeholders of nursing.

The National Qualifications Framework (NQF) was established to address the compartmentalization of education and training, the absence of norms and standards and the need for international recognition. According to the South African Qualifications Authority (1996),this framework was aimed at developing a comprehensive qualifications structure and an integrated approach to education and training in the country (NCHE, 1996:46). Educational institutions, including those for nursing, were challenged with a view to rethink the whole culture of teaching and learning and was counted as knowledge. The major principle of the NQF was the Recognition of Prior Learning (RPL), which had to be persued across all sectors (Musker, 1998: 8). RPL was seen as a means to widen access into learning programs for those who had been historically denied this. The challenge for educational institutions was how to ensure that RPL systems once implemented did not compromise academic standards. Research into methodologies to implement the NF in the absence of mechanisms was then essential. The purpose of the study was to develop and test a RPL model for nurses in South Africa. The study adopted a multi phase decisions-oriented evaluation research design. Stuffelbeam's educational evaluation model was used to guide data collection and analysis. The research questions were incorporated under the different phases of evaluation. The model was development at six levels: level one was at the policy makers level; level two was at the stakeholders; levels three to six were at institutional level where three institutions participated at pilot site for the RPL model development. These levels are presented as tiers in the figure 1. This article present the results of the model development at the first two levels, which according to Stuffelbeam's model is the context evaluation for boundary setting. Part two will present the model development at institutional level, involving the input and process evaluation and depicted as tiers three, and four.

Clinical Competence↗

PubMed2007

Instrument development tools and activities for measure validation using Rasch models: part I - instrument development tools.

Instrument development is an arduous task that, if undertaken with care and consideration, can lay the foundation for the development of validity arguments relating to the inferences and decisions that are based on test measures. This article, Part I of a two-part series, provides an overview of validity concepts and describes how instrument development efforts can be conducted to facilitate the development of validity arguments. Our discussion focuses on documentation of the purpose of measurement, creation of test specifications, item development, expert review, and planning of pilot studies. Through these instrument development activities and tools, essential information is documented that will feed into the analysis, summary, and reporting of data relevant to validity arguments discussed in Part II of this series.

Culture↗

PubMed1990

[The early development of Jacobson's organ in the nasal cavity of the rat before the inception of the secondary palatal development].

The early development of Jacobson's organ was studied by means of a series of embryos of the rat which were of various ages and exactly dated. Already at the youngest stage of those rats, the nasal cavity is just an open groove, the organ is a thickened epithelial layer at the medial nasal process. Only 15 h later, while the nasal grooves start to close from caudal to rostral, Jacobson's organ has acquired the shape of a deep, long cleft, situated within the broad nasal opening. On the 13th d of fetal life, a complete, caudally closed nasal cavity appears. By the means of fundamental growth changes, the already well developed organ has become shifted to a more caudal position and lies now above the primary palate. A shorter caudal part of the still cleft-like organ just starts to close itself thus forming its typical tube-like structure. Moreover strong nerve bundles running from Jacobson's organ to the brain indicate that in the meantime a sensory epithelium can be distinguished. Up to the 15th d of development, the tube-forming process of Jacobson's organ is completed. Parallel to this procedure, the surrounding nasal cavity acquires a caudal apertura nasalis interna by the rupture of the membrana bucconasalis while Jacobson's organ still lies above the rostral primary palate. Primary in the medial, somewhat later in the lateral part of the nasal cavity, first outlines of cartilage appear, visible as dense cell formations. Together with this, the paraseptal cartilage, in these stages closely connected to the septal cartilage, develops quite early. Between the 14th and 15th d of its fetal life, the flat, tube-formed Jacobson's organ of the rat gets turned from a primary horizontal into a vertical position, which brings its sensory epithelium to the medial side. It is assumed that this happens for functional reasons. Because of the obviously early and progressive development of Jacobson's organ within that of the nasal cavity, it seems to be probable that already the origin of the nose, the olfactory placodes, are determined in the directions both of the nasal cavity and of Jacobson's organ. Furthermore the results demonstrate an early preferential development of Jacobson's organ in comparison to that of the surrounding nasal cavity.

Animals↗

PubMed1989

Influence of repeated exposure to rapidly developing hypoxaemia on the arousal and cardiopulmonary response to rapidly developing hypoxaemia in lambs.

Experiments were done on four lambs to determine if repeated exposure to rapidly developing hypoxaemia influences the cardiopulmonary and arousal response from sleep. Each lamb was anaesthetized and instrumented for sleep staging and measurements of arterial haemoglobin oxygen saturation. No sooner than three days after surgery, measurements were made in quiet sleep and active sleep during control periods when the animal was breathing 21% oxygen and during experimental periods of rapidly developing hypoxaemia when the animal was breathing 5% oxygen for approximately 100 epochs of sleep. Arousal occurred from both sleep states during rapidly developing hypoxaemia but was delayed in active sleep compared to quiet sleep. The time to arousal and the decrease in arterial haemoglobin oxygen saturation were significantly increased with repeated exposure to rapidly developing hypoxaemia during both quiet sleep and active sleep. Thus, our data provide evidence that repeated exposure to rapidly developing hypoxaemia produces an arousal response decrement in lambs. Since it is possible that alterations in the arousal response to respiratory stimuli play a role in sudden infant death, studies to investigate the mechanism of the arousal response decrement following repeated exposure to rapidly developing hypoxaemia are warranted.

Animals↗

PubMed2005

Fetal development of striated and smooth muscle sphincters of the male urethra from a common primordium and modifications due to the development of the prostate: an anatomic and histologic study.

BACKGROUND: The aim of the study was to investigate the development of the human urethral sphincter complex during fetal development. METHODS: 23 human male fetal specimens were investigated. The histological sections were processed according to the epoxy resin-based plastination technology. RESULTS: At 9th week of gestation, a combined sphincteric primordium of the rhabdosphincter and the lissosphincter is situated at the anterior and lateral aspects of the membranous and prostatic urethra. Both muscular components assume an omega-shaped configuration due to the presence of a constant connective tissue raphe posterior to the urethra that anchors the rhabdosphincter in the perineal body. Development of the prostate laterally and posteriorly does not modify the growth of the urethral sphincter complex anteriorly but inhibits its development laterally and posteriorly. CONCLUSIONS: The important morphological characteristics of the male adult rhabdosphincter and lissosphincter can be seen very early in fetal development.

Fetal Development↗

PubMed1998

The development of voltage-gated ion channels and its relation to activity-dependent development events.

Spontaneous activity is an essential feature in the development of the nervous system. The patterns of activity and the waveform and ionic dependence of the action potentials that occur during such activity are fine-tuned to carry out certain developmental functions, and are therefore generally not compatible with the mature physiological function of the cell. For this reason, the patterns of ion channel development that create spontaneous activity early in the development of a given cell type are complex and not easily predicted from the mature properties of that same cell. Ion channels are often found that are specific to early stages of development, and that either are not retained in the mature cell or whose properties are greatly changed during later differentiation. The exact significance of such patterns of channel development is just now becoming clear, as we understand more about the mechanisms linking spontaneous activity to later developmental events.

Animals↗

PubMed2006

Who publishes in leading general surgical journals? The divide between the developed and developing worlds.

BACKGROUND: Most articles in top general surgical journals seem to originate from a limited few developed countries. The purpose of this study was to establish which countries publish the most in leading general surgical journals. METHODS: We analysed all the studies, reviews and case reports published in 2003-2004 in 10 leading English-language general surgical journals with the highest impact factors to obtain country-wise data with regard to the origin of articles. Editorials, historical articles, commentaries, guidelines, biographies, interviews and letters to editors were excluded from the analysis. RESULTS: A total of 5,081 articles were reviewed. Out of these, 834 were excluded as detailed above and the remaining 4,247 articles were analysed. Most of these were from USA, European countries, Japan, and Australia. It seems that the vast majority of the world's population living in the developing countries do not find adequate representation in leading general surgical journals. CONCLUSION: Very few articles are published from developing countries in leading general surgical journals. Both developing countries and medical journals need to take steps to curb this trend. Steps are suggested to improve the situation so that the developing world is also adequately represented in the surgical literature.

Authorship↗

PubMed2002

Body mass index, abdominal adiposity and blood pressure: consistency of their association across developing and developed countries.

BACKGROUND: Obesity is increasing worldwide because developing countries are adopting Western high-fat foods and sedentary lifestyles. In parallel, in many of them, hypertension is rising more rapidly, particularly with age, than in Western countries. OBJECTIVE: To assess the relationship between adiposity and blood pressure (BP) in a developing country with high average BP (The Seychelles, Indian Ocean, population mainly of African origin) in comparison to a developed country with low average BP (Switzerland, population mainly of Caucasian origin). DESIGN: Cross-sectional health examination surveys based on population random samples. SETTING: The main Seychelles island (Mahé) and two Swiss regions (Vaud-Fribourg and Ticino). SUBJECTS: Three thousand one hundred and sixteen adults (age range 35-64) untreated for hypertension. MEASUREMENTS: Body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), systolic and diastolic blood pressure (SBP and DBP, mean of two measures). METHODS: Scatterplot smoothing techniques and gender-specific linear regression models. RESULTS: On average, SBP and DBP were found to increase linearly over the whole variation range of BMI, WHR and WC. A modest, but statistically significant linear association was found between each indicator of adiposity and BP levels in separate regression models controlling for age. The regression coefficients were not significantly different between the Seychelles and the two Swiss regions, but were generally higher in women than in men. For the latter, a gain of 1.7 kg/m(2) in BMI, of 4.5 cm in WC or of 3.4% in WHR corresponded to an elevation of 1 mmHg in SBP. For women, corresponding figures were 1.25 kg/m(2), 2.5 cm and 1.8% respectively. Regression coefficients for age reflected a higher effect of this variable on both SBP and DBP in the Seychelles than in Switzerland. CONCLUSION: These findings suggest a stable linear relation of adiposity with BP, independent of age and body fat distribution, across developed and developing countries. The more rapid increase of BP with age observed in the latter countries are likely to reflect higher genetic susceptibility and/or higher cumulative exposure to another risk factor than adiposity.

Abdomen↗

PubMed1995

Assessing children's development using parents' reports. The Child Development Inventory.

The Child Development Inventory (CDI), completed by parents at home, assesses the development of social, self-help, motor, language, letter and number skills, and presence of symptoms and behavior problems of children between the ages of 15 months and 5 years. The results provide the pediatrician with a profile of the child's development, problems, and strengths, and are an aid to comprehensive assessment. CDI norms and validity were determined for a community sample of 568 children. The CDI developmental scales correlate closely with age (r = 0.84). CDI results identified all the normative group children who were enrolled in early childhood/special education (N = 26) and correlated with academic achievement for children in kindergarten (N = 132). CDI scales correlated with reading achievement in kindergarten as follows: general development 0.69, letters 0.56, language comprehensive 0.42, expressive language 0.36, and self-help 0.35. Thus, the CDI provides a useful measure of children's development and, because of its reliance on parental reports, offers an effective approach to developmental assessment in the busy pediatric practice.

Case-Control Studies↗

PubMed2004

Comparing gay identity development theory to cognitive development: an empirical study.

The relationship between gay identity development and cognitive development, as outlined by Ivey's Developmental Counseling Therapy Model, was explored. The Gay Identity Questionnaire and the Standard Developmental Counseling Interview were administered to 78 gay men. Results suggested that there is a relationship between gay identity development and cognitive development. In addition, the findings provide evidence that gay identity development can be categorized by concrete and abstract frames of reference.

Adult↗

PubMedDate not supplied

Developing drugs for developing countries.

Infectious and parasitic diseases create enormous health burdens, but because most of the people suffering from these diseases are poor, little is invested in developing treatments. We propose that developers of treatments for neglected diseases receive a "priority review voucher." The voucher could save an average of one year of U.S. Food and Drug Administration (FDA) review and be sold by the developer to the manufacturer of a blockbuster drug. In a well-functioning market, the voucher would speed access to highly valued treatments. Thus, the voucher could benefit consumers in both developing and developed countries at relatively low cost to the taxpayer.

Anti-Infective Agents↗

PubMed1997

Physical assessment: a vital nursing tool in both developing and developed countries.

In developed countries such as the United States and Great Britain, the use of technology to assess and diagnose a patient's health status is often taken for granted. In developing countries, however, the lack of available technology, replacement parts, and ability to maintain the machinery is severely limited. More often than not, diagnosis and consequent treatment are decided through physical assessment findings alone. It is therefore imperative that critical care nurses in developing countries acquire and utilize good physical assessment skills to enhance quality nursing care. This article focuses on physical assessment skills from a global perspective, emphasizing the value of this knowledge and its application to clinical practice for critical care nurses in both developing and developed countries.

Critical Care↗

PubMed1979

[Medical development cooperation in the Confederation. The international framework and the important place of public health in Swiss development cooperation].

The systematic organization of health services in the developing countries to benefit the majority of the population is seen as an important contribution toward the general economic and social development of these countries. This view is uncontested today, but was given less importance in the early years of Swiss development aid. The Swiss Development Cooperation's support of health services is now integrated into its overall program to satisfy the basic needs of the people of the developing countries.

Developing Countries↗