Downregulation of Forkhead box F1 gene expression in the pulmonary vasculature of nitrofen-induced congenital diaphragmatic hernia.

PURPOSE: High mortality and morbidity in infants born with congenital diaphragmatic hernia (CDH) are attributed to pulmonary hypoplasia and pulmonary hypertension (PH). Forkhead box (Fox) transcription factors are known to be crucial for cell proliferation and homeostasis. FoxF1 is essential for lung morphogenesis, vascular development, and endothelial proliferation. Mutations in FoxF1 and also the Fox family member FoxC2 have been identified in neonates with PH. In human and experimental models of arterial PH, the Fox protein FoxO1 was found to be downregulated. We hypothesized that Fox expression is altered in the lungs of the nitrofen-induced CDH rat model and investigated the expression of FoxF1, FoxC2, and FoxO1. METHODS: Following ethical approval (Rec 913b), time-pregnant Sprague-Dawley rats received nitrofen or vehicle on gestational day (D9). Fetuses were sacrificed on D21, inspected for CDH and divided into CDH (n = 11) and control group (n = 11). Gene expression of FoxF1, FoxC2, and FoxO1 was evaluated with qRT-PCR. Detected alterations of mRNA levels were subsequently assessed on the protein level by performing western blot analysis and laser scanning confocal microscopy. RESULTS: The relative mRNA level of FoxF1 was significantly downregulated in CDH lungs compared to controls (FoxF1 CDH 1.047 ± 0.108, FoxF1 Ctrl 1.419 ± 0.01, p = 0.014). Relative mRNA levels of FoxC2 and FoxO1 were not found to be altered between the experimental groups (FoxC2 CDH 30.74 ± 8.925, FoxC2 Ctrl 27.408 ± 7.487, p = 0.776; FoxO1 CDH 0.011 ± 0.002, FoxO1 Ctrl 0.011 ± 0.001, p = 0.809). On the protein level, western blotting demonstrated a reduced pulmonary protein expression of FoxF1 in CDH lungs. Confocal microscopy showed a markedly diminished expression of FoxF1 in the pulmonary vasculature of CDH lungs compared to controls. CONCLUSION: Our study demonstrates a strikingly reduced expression of FoxF1 in the pulmonary vasculature of nitrofen-induced CDH. Altered FoxF1 gene expression during embryogenesis may participate in vascular maldevelopment resulting in PH in this animal model.

Xenopus embryonic spinal neurons express potassium channel Kvbeta subunits.

Developmental regulation of voltage-dependent delayed rectifier potassium current (I(Kv)) of Xenopus primary spinal neurons regulates the waveform of the action potential. I(Kv) undergoes a tripling in density and acceleration of it activation kinetics during the initial day of its appearance. Another voltage-dependent potassium current, the A current, is acquired during the subsequent day and contributes to further shortening of the impulse duration. To decipher the molecular mechanisms underlying this functional differentiation, we are identifying potassium channel genes expressed in the embryonic amphibian nervous system. Potassium channels consist of pore-forming (alpha) as well as auxiliary (beta) subunits. Here, we report the primary sequence, developmental localization, and functional properties of two Xenopus Kvbeta genes. On the basis of primary sequence, one of these (xKvbeta2) is highly conserved with Kvbeta2 genes identified in other species, whereas the other (xKvbeta4) appears to identify a new member of the Kvbeta family. Both are expressed in developing spinal neurons during the period of impulse maturation but in different neuronal populations. In a heterologous system, coexpression of xKvbeta subunits modulates properties of potassium current that are developmentally regulated in the endogenous I(Kv). Consistent with xKvbeta4's unique primary sequence, the repertoire of functional effects it has on coexpressed Kv1alpha subunits is novel. Taken together, the results implicate auxiliary subunits in regulation of potassium current function and action potential waveforms in subpopulations of embryonic primary spinal neurons.

Overexpression of potassium channel RNA: in vivo development rescues neurons from suppression of morphological differentiation in vitro.

Neuronal differentiation often proceeds differently in vitro than it does in vivo. Previous work demonstrated that overexpression of potassium channel RNA reduces the number of morphologically identifiable neurons that appear in cultures prepared from neural plate stage (17-1/2 hr) embryos (Jones and Ribera, 1994). Here, we report that morphological differentiation of neurons in situ is only slightly affected by overexpression of potassium channels. Endogenous factors appear to compensate for the effect of channel overexpression. Consistent with this view, when cultures are prepared from older neural tube embryos (22-24 hr), more neurons containing excess potassium channel RNA differentiate morphologically in vitro. Exposure in situ to a rapid intracellular calcium chelator, but not to tetrodotoxin, omega-conotoxin or a slow calcium chelator, prevents the compensation provided by extended development in vivo. Typically, RNA overexpression is limited to half of the embryo in order to provide an internal control. However, when potassium channel RNA is overexpressed throughout the embryo, few neurons differentiate morphologically in vitro, even if cultures are prepared from older neural tube embryos. Thus, recovery is possible if a minimum of 5 hr of further development in vivo is allowed under conditions in which rapid elevations of intracellular calcium are permitted and half of the nervous system has normal levels of potassium channel RNA. These results suggest that different or additional mechanisms operate in situ than in vitro to promote morphological differentiation of neurons.

Contraception in adolescence: a review. 2. Biomedical aspects.

PIP: Although none of the currently available methods of contraception can be considered ideal for use by adolescents, many come reasonably close. The present article reviews the relative benefits and risks associated with each method. Oral contraceptives (OCs) appear to bear few specific risks for adolescents. Pills containing 30-50 mcg of ethinyl estradiol and 0.5-1.0 mg norethisterone, or their equivalents, offer a high degree of protection and are well tolerated. There is no evidence that the pill interferes with either pubertal growth or the achievement of regular ovulation. Risks of cardiovascular complications are lower for adolescents than any other age group; however, changes in lipid profiles, which are thought to contribute to increased atherogenesis, may restrict total lifetime use of OCs. While the minimal compliance requirements of the IUD might suggest it as an appropriate method for adolescents, cramping and increased menstrual blood flow often make it unacceptable. Expulsion rates are higher in nulligravidae than in parous females, although copper wound or progestogen-impregnated devices are better retained. The increased risk of pelvic inflammatory disease in unmarried adolescents using the IUD is of sufficient magnitude to warrant the restriction of the device to those who have failed to use other methods. Depot medroxyprogesterone acetate (injectable hormonal contraceptive) may be of use in particular groups of adolescents. Both the World Health Organization and the American Academy of Pediatrics recommend its use in selected groups of adolescents for whom other methods are contraindicated. Oral progestogen-containing minipills are not suitable for teenagers, since compliance requirements are fairly rigid, and there is often excessive breakthrough bleeding, and a relatively low protection rate. All barrier methods have a significant place for use by adolescents, although younger teens are often reluctant to insert the diaphragm. The condom, used alone or with spermicidal foam, has a particular advantage since it does not require a prescription, is widely available, and suits the spontaneous, unplanned nature of coitus among this age group. Rhythm and other forms of natural birth control are not suitable for adolescents. They depend on regular ovulation and require extensive instruction, a high degree of motivation, and the ability to plan ahead for coitus. None of these factors is characteristic of the teenage girl. (author's modified)^ieng

Contraception in adolescence: a review. 1. Psychosocial aspects.

PIP: Use of contraception among adolescents, particulary those unmarried, is significantly different from that among older couples, and is influenced by educational, developmental, social, and psychological factors. Even when family planning services are available and teens are properly educated, compliance tends to be poor. Contributory factors to poor contraceptive use include: services not attuned to adolescent needs; lack of guaranteed confidentiality; unsuitable contraceptive methods; little psychological support; immaturity of cofnitive thought processes in the adolescent with an inability to appreciate longterm consequences of current acts; and a developmental tendency to take risks coupled with a denial of the possibility of pregnancy. A particularly significant finding is the importance of psychological conflict associated with sexual activityand contraception. The adolescent suffers less anxiety by denying the risk of pregnancy than by taking responsibility for it through conscious, consistent contraception. The emotional costs of admitting the possibility of pregnancy are unacceptably high in terms of personal devaluation, guilt, and risk of rejection by the partner. Family planning programs for unmarried adolescents should include clinic sessions exclusively for young people, after school; they should guarantee privacy and confidentiality, and should accept the adolescent in a nonjudgemental manner. Examinations should be carried out in such a way as to minimize embarassment, and thorough counseling should be available to allow the adolescent to choose a suitable method. Frequent follow-up should be arrangged, and particular attention should be given to identifying and relieving conflict. Broad social policy also can influence adolescent contraceptive behavior. Sex education in schools and through the media has significantly improved levels of contraceptive use among teens. There is not evidence that such initiatives promote premarital sexual activity. (author's modified)^ieng

"Red herrings," adolescents, and testicular tumors.

Testicular tumors, although rare in the general population, comprise the most common class of solid tumors in males aged 15-34 years. Although commonly appearing as a painless scrotal mass, one-third of testicular tumor cases are accompanied by pain or other atypical symptoms that may confound diagnosis, particularly if the clinician is misdirected by other issues. In this case report of an adolescent male with embryonal cell carcinoma of the right testis, a premorbid history of psychological problems, and immature, complaining behavior led to an improper assessment of the significant clues in the patient's oral history and a delay in diagnosis.

Adolescent pregnancy.

PIP: The combination of an uncertain social climate and the impulsiveness of youth have contributed to an increasing incidence of teenage pregnancy, with its attendant problems. The medical risk to mother and child related to poor or nonexistent prenatal care has already been well documented. Compounding this already serious problem is the lack of social, economic or educational support services for the increasing number of young mothers who opt to continue to term and to keep their babies. The cumulative psychological effect of premature motherhood, although not extensively studied, is one which health and social care professionals should be aware of, particularly as these disturbances might affect the well being of the growing child. The role of the primary care physician in these situations is a unique one, lending itself to timely intervention. The routine physical examination provides an opportunity to investigate sexual concerns of the teenaged patient, to offer contraceptive counseling, and to encourage education in sexual matters. Testing for pregnancy should be carried out with meticulous concern for thoroughness, and should aim at establishing a correct diagnosis in as short a time as possible. Once pregnancy has been established, all options should be discussed. The patient should be offered unbiased counsel by a professional sensitive to the ramifications of choices likely to be made regarding continuation or termination of pregnancy. The greatest need, however, is that of supportive services for the young mother and her newborn infant since the consequences of adolescent motherhood can be permanent for all concerned.^ieng

A perspective on the brittle teenage diabetic.

The brittle teenage diabetic presents a difficult problem well known to clinicians. It is the authors' contention that its major component is psychological and not biological, and that much of this poor control can be avoided by proper developmental planning from the onset of disease. Failure to modify transactional health care models appropriate for the child to that appropriate for the adolescent accounts for much of this difficulty. Anticipatory long-range planning is outlined to aid the physician in allowing the youth to isolate and insulate his diabetes from becoming either a focus for control contests and power struggles or a maladaptive, manipulative regressive behavior. The reasonable goal is to prevent any further hospitalizations for ketoacidosis or hypoglycemia beyond the first admission for diagnosis and initial stabilization. Five illustrative cases augment this discussion.

Psychological factors in diabetes mellitus. A review of the literature with emphasis on adolescence.

In this thorough review of the literature of the past 100 years concerning psychological factors in diabetes mellitus, interpretation is channeled toward adolescence. In addition, emphasis is given to the major role that emotional components play in the development and maintenance of the brittle teenage diabetic. The integration of adolescent developmental issues of into physician treatment plans is stressed.

Chorioretinitis in the adolescent: two case presentations with discussion.

Two cases of chorioretinitis in adolescence demonstrate the characteristic course of events. It is typically caused by Toxoplasma gondii and is usually acquired congenitally. Toxocara infection must be considered in younger children. Other etiologic agents are rarely implicated in children and youth. Diagnosis of toxoplasmic chorioretinitis is based on a characteristic history of visual disturbance and specific funduscopic appearance, along with confirmatory serological studies. Management is complex, utilizing pyrimethamine (Daraprim), sulfadiazine, and prednisone in combination for several weeks or months. The combined long-term care by the physician generalist and ophthalmologist is essential. Recognition of adolescent developmental issues is important to insure optimal compliance. The prognosis is guarded, with 5% to 30% recurrence rates noted after treatment. Severe visual impairment may be seen.