Growth impairment after TBI of leukemia survivors children: a model- based investigation

BACKGROUND

Children receiving Total Body Irradiation (TBI) in preparation for Hematopoietic Stem Cell Transplantation (HSCT) are at risk for Growth Hormone Deficiency (GHD), which sometimes severely compromises their Final Height (FH). To better represent the impact of such therapies on growth we apply a mathematical model, which accounts both for the gompertzian-like growth trend and the hormone-related 'spurts', and evaluate how the parameter values estimated on the children undergoing TBI differ from those of the matched normal population.

METHODS

25 patients long-term childhood lymphoblastic and myeloid acute leukaemia survivors followed at Pediatric Onco-Hematology, Stem Cell Transplantation and Cellular Therapy Division, Regina Margherita Children's Hospital (Turin, Italy) were retrospectively analysed for assessing the influence of TBI on their longitudinal growth and for validating a new method to estimate the GH therapy effects. Six were treated with GH therapy after a GHD diagnosis.

RESULTS

We show that when TBI was performed before puberty overall growth and pubertal duration were significantly impaired, but such growth limitations were completely reverted in the small sample (6 over 25) of children who underwent GH replacement therapies.

CONCLUSION

Since in principle the model could account for any additional growth 'spurt' induced by therapy, it may become a useful 'simulation' tool for paediatricians for comparing the predicted therapy effectiveness depending on its timing and dosage.

Pediatric brain tumor treatment: growth consequences and their management

Tumors of the central nervous system, the most common solid tumors of childhood, are a major source of cancer-related morbidity and mortality in children. Survival rates have improved significantly following treatment for childhood brain tumors, with this growing cohort of survivors at high risk of adverse medical and late effects. Endocrine morbidities are the most prominent disorder among the spectrum of longterm conditions, with growth hormone deficiency the most common endocrinopathy noted, either from tumor location or after cranial irradiation and treatment effects on the hypothalamic/pituitary unit. Deficiency of other anterior pituitary hormones can contribute to negative effects on growth, body image and composition, sexual function, skeletal health, and quality of life. Pediatric and adult endocrinologists often provide medical care to this increasing population. Therefore, a thorough understanding of the epidemiology and pathophysiology of growth failure as a consequence of childhood brain tumor, both during and after treatment, is necessary and the main focus of this review.

In utero exposure to therapeutic radiation for Hodgkin lymphoma

QUESTION

One of my patients was incidentally found to be pregnant after completion of radiotherapy for Hodgkin lymphoma. What are the possible effects that I should discuss with her before she makes a final decision regarding continuation of her pregnancy?

ANSWER

Radiotherapy might not be an absolute contraindication in pregnant women who are diagnosed with cancer located in areas remote from the pelvis. However, the fetal exposure should be carefully estimated, and the known dose-response information has to be discussed individually to allow informed decisions to be made.

[The influence of electromagnetic fields on flora and fauna]

This paper presents the influence of natural and artificial electromagnetic fields (EMF) on fauna and flora. The mechanisms of Earth's magnetic field detection and the use of this skill by migratory animals to faultlessly reach the destination of their travel are discussed, as well as the positive effects of electric and magnetic fields on plants relative to their physiology, yielding and health. EMF influence on social insects and animal organisms, including possible DNA damages and DNA repair systems, is presented. The influence of high frequency electromagnetic fields on birds nesting is also discussed.

Indian herb 'Sanjeevani' (Selaginella bryopteris) can promote growth and protect against heat shock and apoptotic activities of ultra violet and oxidative stress

Selaginella bryopteris is a lithophyte with remarkable ressurection capabilities. It is full of medicinal properties, hence also known as 'Sanjeevani' (one that infuses life). For lack of credible scientific evidence the plant is not in active use as a medicinal herb. We provide scientific evidence for why S. bryopteris is known as 'Sanjeevani'. The aqueous extract of S. bryopteris possesses growth-promoting activity as well as protective action against stress-induced cell death in a number of experimental cell systems including mammalian cells. Treatment of the cells in culture with 10% aqueous extract enhanced cell growth by about 41% in Sf9 cells and 78% in mammalian cells. Pre-treatment of cells with the Selaginella extract (SE) (1-2.5%) protected against oxidative stress (H2O2) -induced cell death. The killing potential of ultra violet (UV) was also significantly reduced when the cells were pre-treated with SE for 1 h. Thermal radiation suppressed cell growth by about 50%. Pre-treatment of cells with SE for 1 h afforded complete protection against heat-induced growth suppression. SE may possess anti-stress and antioxidant activities that could be responsible for the observed effects. Chemical analysis shows that SE contains hexoses and proteins. Taken together, S. bryopteris extract may help in stress-induced complications including those due to heat shock.

Radioprotection of craniofacial bone growth

In this review, the potential of pharmacologic therapy for prevention of radiation-induced bone growth inhibition is discussed. Significant radioprotection using the radioprotector Amifostine has been achieved in animal models of radiation-induced retardation of long and craniofacial bone growth. Moreover, radioprotection in vitro has been achieved in a number of cell lines, including osteoblast-like, endothelial, and fibroblastic. This evidence may support future clinical investigations of radioprotector Amifostine or similar substances for radioprotection of the growing craniofacial skeleton.

Final height in pediatric patients after hyperfractionated total body irradiation and stem cell transplantation

Impaired linear growth has been shown to occur in individuals treated during childhood with single-dose and fractionated total body irradiation (TBI) before stem cell transplantation. Our objective was to describe the final heights attained and patient/treatment factors correlating with final height in a cohort of childhood cancer survivors treated with hyperfractionated TBI (total dose 1375 or 1500 cGy). Thirty individuals (18 men) were included in the study. The mean final height standard deviation score (s.d.s.) was -1.9 +/- 0.2, significantly lower than height s.d.s. at TBI (-0.2 +/- 0.2, P < 0.001). Final height s.d.s. was significantly correlated with age at diagnosis, age at TBI and target height (P = 0.04, P < 0.001, P < 0.001, respectively). Treatment with growth hormone (GH) (n = 7) maintained mean height s.d.s. at -2.0 from the onset of GH therapy until attainment of final height. The mean final sitting height s.d.s. was -2.2 +/- 0.2 (n = 16), significantly shorter than mean final standing height s.d.s. (P < 0.01). In conclusion, treatment with hyperfractionated TBI is associated with a reduction in standing height and an even greater reduction in sitting height. Final height after hyperfractionated TBI was similar to that reported after fractionated TBI.

Effects of UVB radiation on marine and freshwater organisms: a synthesis through meta-analysis

Ultraviolet-B (UVB) radiation is a global stressor with potentially far-reaching ecological impacts. In the first quantitative analysis of the effects of UVB on aquatic organisms, we used meta-analytic techniques to explore the effects of UVB on survival and growth in freshwater and marine systems. Based on the large body of literature on the effects of UVB in aquatic systems, we predicted that UVB would have different effects in different habitats, experimental venues, trophic groups and life history stages. Contrary to our predictions, we found an overall negative effect of UVB on both survival and growth that crossed life histories, trophic groups, habitats and experimental venues. UVB had larger negative effects on growth in embryos compared with later life history stages. Despite the overall negative effect of UVB, effect sizes varied widely. In the survival analyses, no relationship between mean effect size and taxonomic groups or levels of exposure to UVB was detected. In the growth analyses, a larger negative effect on protozoans was observed. Our analyses suggest that the effects of UVB in aquatic systems are large and negative but highly variable between organisms. Variation in susceptibility may have important implications for population and community structure.

Impact of TBI on late effects in children treated by megatherapy for Stage IV neuroblastoma. A study of the French Society of Pediatric oncology

PURPOSE

To determine the contribution of total body irradiation (TBI) to late sequelae in children treated with high-dose chemotherapy and autologous bone marrow transplantation for Stage IV neuroblastoma.

PATIENTS AND METHODS

We compared two populations that were similar with regard to age, stage, pre-autologous bone marrow transplantation chemotherapy (CT) regimen, period of treatment, and follow-up (12 years). The TBI group (n = 32) received TBI as part of the megatherapy procedure (1982-1993), whereas the CT group (n = 30) received conditioning without TBI (1985-1992). Analysis 12 years later focused on growth, weight and corpulence (body mass index) delay; hormonal deficiencies; liver, kidney, heart, ear, eye, and dental sequelae; school performance; and the incidence of secondary tumors.

RESULTS

Impact of TBI was most marked in relation to growth and weight delay, although the mean delay was not severe, probably because of treatment with growth hormones. Other consequences of TBI were thyroid insufficiency, cataracts, and a high incidence of secondary tumors. Hearing loss and dental agenesis were more prominent in the group treated with CT alone. No differences were observed in school performance.

CONCLUSION

The most frequent side effects of TBI were cataracts, thyroid insufficiency, and growth delay, but more worrying is the risk of secondary tumors. Because of the young mean age of patients and the toxicity of TBI regimens without any survival advantage, regimens without TBI are preferable in the management of Stage IV neuroblastoma.

Radiation-induced craniofacial bone growth inhibition: efficacy of cytoprotection following a fractionated dose regimen

BACKGROUND

Severe craniofacial growth disturbances are noted in 66 to 100 percent of children with head and neck cancers who received radiotherapy during their growing years. The authors have previously demonstrated the prevention of radiation-induced craniofacial bone growth inhibition following single-dose orthovoltage radiation to the orbitozygomatic complex in an infant rabbit model through the administration of the cytoprotective agent amifostine (WR-2721) before radiation treatment. The purpose of this study was to investigate the efficacy of cytoprotection using a fractionated dose regimen that better approximates the clinical application of radiation therapy.

METHODS

Thirty 7-week-old male New Zealand rabbits were randomized into three groups (n = 10), each receiving six fractions of orthovoltage radiation to the right orbitozygomatic complex: group C, sham irradiation control; group F35, total dose of 35 Gy; and group F35A, total dose of 35 Gy with administration of amifostine 200 mg/kg intravenously 20 minutes before each fraction. Bone growth was evaluated up to skeletal maturity (age 21 weeks) with serial radiographs and computed tomography scans for cephalometric analysis, bone volume, and bone density measurements.

RESULTS

Fractionated radiation resulted in significant (p < 0.05) bone growth inhibition compared with sham radiation in 16 of 21 cephalometric parameters measured and significantly (p < 0.05) reduced bone volume of the rabbit orbitozygomatic complex. Pretreatment with amifostine before each radiation fraction prevented growth deformities in four cephalometric parameters and significantly (p < 0.05) attenuated these effects in another seven parameters compared with radiated animals. Bone volumes were also significantly (p < 0.05) improved in F35A animals compared with F35 animals.

CONCLUSIONS

This study establishes that fractionation of orthovoltage radiation does not prevent the development of growth disturbances of the rabbit craniofacial skeleton and also demonstrates that preirradiation administration of amifostine is highly effective in the prevention and attenuation of radiation-induced craniofacial bone growth inhibition.

Long-term effects of radiation therapy on cognitive and endocrine function in children with leukemia and brain tumors

BACKGROUND

As the number of long-term survivors of childhood cancer has grown, it has become increasingly clear that central nervous system therapy may have serious long-term effects on cognition and endocrine function. These complications have been studied most extensively in children with brain tumors and leukemia.

REVIEW SUMMARY

Children with acute lymphoblastic leukemia previously treated with cranial irradiation are at risk for cognitive decline. Chemotherapy-only regimens, which rely on high-dose frequently administered methotrexate, are also associated with producing cognitive dysfunction. Children irradiated for brain tumors are even more vulnerable. Risk factors include perioperative morbidity, young age, large-volume high-dose cranial irradiation, supra-tentorial location of tumor, moyamoya syndrome, and leukoencephalopathy. Cognitive decline is progressive over at least a decade. The most common radiation-induced endocrinopathies are hypothyroidism and growth hormone deficiency. Treatment effects on growth are multifactorial and include growth hormone deficiency,spinal shortening, precocious puberty, undetected hypothyroidism,and poor nutrition. Fifty percent to 80% of children treated with craniospinal radiation for brain tumors will experience growth failure. In hopes of reducing neurotoxicity, current treatments limit the dose and volume of radiation while adding chemotherapy. Results have not been uniformly positive, however, and may increase toxicity in some cases.

CONCLUSIONS

The standard of care in 2004 is that children who have been treated for brain tumors and leukemia should be monitored for cognitive and endocrine dysfunction. Until effective non-neurotoxic treatment is identified, long-term effects assessments are essential to maximize the quality of life of survivors of childhood cancer.

The effects of electromagnetic fields from power lines on avian reproductive biology and physiology: a review

Electrical power lines are ubiquitous in the developed world and in urban areas of the developing world. All electrical currents, including those running through power lines, generate electric and magnetic fields (EMFs). Electrical power lines, towers,and distribution poles are used by birds for perching, hunting, and nesting. Therefore, many bird species, like humans, are exposed to EMFs throughout their lives. EMFs have been implicated in adversely affecting multiple facets of human health,including increasing the risks of life-threatening illnesses such as leukemia, brain cancer, amyotrophic lateral sclerosis, clinical depression, suicide, and Alzheimer's disease. A great deal of research and controversy exists as to whether or not exposure to EMFs affects the cellular, endocrine, immune, and reproductive systems of vertebrates. Laboratory work has used mice, rats, and chickens as models for this EMF research in an effort to understand better the possible implications of EMF exposure for humans. However, EMF exposure of wild birds may also provide insight into the impacts of EMFs on human health. This review focuses on research examining the effects of EMFs on birds; most studies indicate that EMF exposure of birds generally changes, but not always consistently in effect or in direction, their behavior, reproductive success, growth and development, physiology and endocrinology, and oxidative stress under EMF conditions. Some of this work has involved birds under aviary conditions, while other research has focused on free-ranging birds exposed to EMFs. Finally, a number of future research directions are discussed that may help to provide a better understanding of EMF effects on vertebrate health and conservation.

Developmental effects of electromagnetic fields

This paper reviews experimental studies on the effects of radiofrequency (RF), extremely low frequency (ELF), and intermediate frequency (IF) electromagnetic fields on animal development. Numerous studies have shown that RF fields are teratogenic at exposure levels sufficiently high to cause significant increase of temperature. There is no consistent evidence of RF field effects at nonthermal exposure levels. Only a few studies have evaluated possible effects on postnatal development using sensitive endpoints, such as behavioral effects. ELF electric fields up to 150 kV/m have been evaluated in several mammalian species. The results are rather consistent and do not suggest adverse developmental effects. The results of studies on ELF magnetic fields suggest effects on bird embryo development, but not consistently in all studies. Results from experiments with other non-mammalian experimental models have also suggested subtle effects on developmental stability. In mammals, most studies have shown no effects of prenatal exposure to ELF or IF magnetic on gross external, visceral, or skeletal malformations. The only finding that shows some consistency is increase of minor skeleton alterations in several experiments. Taken as a whole, the results do not show robust adverse effects of ELF and IF fields on development. However, additional studies on the suggested subtle effects on developmental stability might increase our understanding of the sensitivity of biological organisms to weak low-frequency magnetic fields.

Growth patterns and final height of survivors of childhood leukemia

Growth patterns of 85 survivors of childhood leukemia were analyzed retrospectively. All patients remained in first remission with no central nervous system involvement. The mean age at diagnosis was 5.8 +/- 3.6 years. The diagnoses were acute lymphoblastic leukemia (ALL) in 68 patients (80%) and acute non-lymphoblastic leukemia (ANLL) in 17 patients (20%). All except two patients received cranial irradiation: 51 patients with 1,800 cGy and 32 patients with 2,400 cGy. Mean height SDS was -0.7 +/- 1.36 at the time of diagnosis, which decreased to -0.92 +/- 1.31 by the end of treatment, and further decreased to -1.14 +/- 1.38 at 6 years after cessation of treatment. Mean weight SDS was -0.55 +/- 1.13 at the time of diagnosis, increasing slightly to -0.39 +/- 1.02 at the end of treatment, and decreasing to -0.46 +/- 1.65 at 6 years after cessation of treatment. Of these survivors, 51 patients (26 boys and 25 girls) reached a final height that was 1.04 SDS or 5.3 cm less than their target height. There was no difference of height and weight SDS between patients with ALL and ANLL. Girls and boys had different growth patterns. Girls had a slightly increased height SDS and gained more weight after cessation of treatment, resulting in less final height deficit and overweight for height, whereas boys had further height and weight reduction resulting in more deficit of final height.

[Radiation-induced and embryotoxic effects in experimental hyperthyroidism]

The purpose of this article was investigation the development of the posterity rat (line Wistar) in the postnatal ontogenesis after combined and separate action of gamma-radiation (1.25 Gy at 20 days) and hyperthyroidism, provoked by toxic thyroid doses of 100 mg thyroidin per rat. It was shown that hyperthyroidism did not affect physical development of the irradiated posterity, but in a long-time period (7 month) it was revealed a decrease in ability to the training of posterity rats after the combined action of the factors.

Growth and puberty after treatment for acute lymphoblastic leukemia

Over the last 20 years, after combining treatment of chemotherapy and radiotherapy, there has been an improvement in the survival rate of acute lymphoblastic leukemia patients, with a current cure rate of around 70%. Children with the disease have been enrolled into international treatment protocols designed to improve survival and minimize the serious irreversible late effects. Our oncology unit uses the international protocol: GBTLI LLA-85 and 90, with the drugs methotrexate, cytosine, arabinoside, dexamethasone, and radiotherapy. However, these treatments can cause gonadal damage and growth impairment. PATIENTS AND METHOD: The authors analyzed 20 children off therapy in order to determine the role of the various doses of radiotherapy regarding endocrinological alterations. They were divided into 3 groups according to central nervous system prophylaxis: Group A underwent chemotherapy, group B underwent chemotherapy plus radiotherapy (18 Gy), and group C underwent chemotherapy plus radiotherapy (24 Gy). Serum concentrations of LH, FSH, GH, and testosterone were determined. Imaging studies included bone age, pelvic ultrasound and scrotum, and skull magnetic resonance imaging. RESULTS: Nine of the patients who received radiotherapy had decreased pituitary volume. There was a significant difference in the response to GH and loss of predicted final stature (Bayley-Pinneau) between the 2 irradiated groups and the group that was not irradiated, but there was no difference regarding the radiation doses used (18 or 24 Gy). The final predicted height (Bayley-Pinneau) was significantly less (P = 0.0071) in both groups treated with radiotherapy. Two girls had precocious puberty, and 1 boy with delayed puberty presented calcification of the epididymis. CONCLUSION: Radiotherapy was been responsible for late side effects, especially related to growth and puberty.

[Physical development of children in the rural area of the Gomel region in post-Chernobyl period]

The results of screening of 200 children (88 boys and 112 girls) aged from 8 to 13 residing in rural areas with the environment contaminated with radioisotopes-traces of Chernobyl disaster. Changes in body weight, height and height-mass coefficient were shown. Disharmonious development of the children studied was demonstrated in age-sex dependence.

Long-term effects in children treated with radiotherapy for head and neck rhabdomyosarcoma

PURPOSE

To examine the long-term effects of treatment in children receiving radiotherapy for head and neck rhabdomyosarcoma.

METHODS

From 1967 to 1994, a total of 30 children with head and neck rhabdomyosarcoma received megavoltage radiotherapy at one institution. Seventeen patients (57%) have survived and have at least a 5-year follow-up. There were 11 males and 6 females, with a median age of 5.7 years (range 2.2-11.6) at the time of radiotherapy. Tumor location was orbit in 6 patients, infratemporal fossa in 4, paranasal sinuses in 2, and supraglottic larynx in 2; the nasopharynx, pterygopalatine fossa, and parotid gland were sites for the remaining children. All but 2 patients had tumors of embryonal histology. The Intergroup Rhabdomyosarcoma Study (IRS) Group was I in 2, II in 3, and III in 11 children; 1 patient had a recurrent tumor after surgery alone. Radiotherapy volume was the primary tumor or tumor bed in 13, tumor and whole brain in 3, and tumor and craniospinal axis in 1. Median radiotherapy dose to the primary site was 5,040 cGy (range 4,140-6,500) and to the whole brain was 3,000 cGy. All but 1 were treated with 150-200-cGy fractions; 1 patient received 250-cGy fractions for a tumor in the larynx. Chemotherapy was vincristine (V), actinomycin-D (A), and cyclophosphamide (C) in 10 patients, VAC + adriamycin in 2, VA in 1, VA + ifosfamide in 1, VC + adriamycin in 1, and none in 2. One patient had salvage chemotherapy consisting of cisplatin and etoposide. Median follow-up time was 20 years (range 7.5-33).

RESULTS

Late effects of treatment were seen in all patients and included facial growth retardation in 11, neuroendocrine dysfunction in 9, visual/orbital problems in 9, dental abnormalities in 7, hearing loss in 6, and hypothyroidism in 3. Intellectual and academic delays were documented in 3 patients who had received whole brain radiotherapy. While neuroendocrine, thyroid, dental, and cognitive sequelae were primarily attributed to radiotherapy, hearing loss was thought to be a direct result of tumor destruction and, in 1 case, cisplatin chemotherapy. Late effects at or beyond 10 years from radiotherapy were few, but severe, and included chondronecrosis, esophageal stenosis, second malignancy, and brain hemorrhage.

CONCLUSION

Late effects of treatment in children receiving radiotherapy for head and neck rhabdomyosarcoma are frequent. Although radiotherapy is a significant contributor of neuroendocrine, dental, thyroid, and cognitive toxicity, it is not usually implicated with hearing loss. Late toxicity of treatment beyond 10 years is not as frequent as those occurring within 10 years of therapy.

Cranial irradiation of female rats causes dose-dependent and age-dependent activation or inhibition of pubertal development

Cranial irradiation in prepubertal children with leukemia or brain tumors can lead to precocious or in high doses to late puberty. To unravel the underlying mechanisms, we developed a rat model with selective cranial Co60-irradiation technique. Infantile (12-16 d old) or juvenile (21-23 d old) female Sprague-Dawley rats received a single dose of 4, 5, 6, 9 or 2 x 9 Gy (at days 21 and 23). Each group consisted of 7-20 animals. High radiation doses (9 Gy and more) caused retardation of sexual development, whereas low radiation doses (5 or 6 Gy) led to accelerated onset of puberty in 20% of infantile irradiated rats animals as determined by vaginal opening. Interestingly, at peripubertal age (postnatal day 32-34), 5 or 6 Gy infantile irradiated rats had significantly higher serum LH levels stimulated by GnRH and estradiol levels (p < 0.05). 2 x 9 Gy irradiated rats had at the age of 3 mo a marked growth retardation and significantly lower GH levels than the controls (p < 0.05) whereas prolactin, FSH, TSH, T4, and corticosterone levels were comparable with controls. These studies demonstrate that the GnRH-pulse generator is very radiosensitive as precocious activation occurred after low dose irradiation (5 or 6 Gy) of infantile rats without any other endocrine disorder. High radiation doses (9 or 2 x 9 Gy) induced retardation of sexual maturation and later on growth hormone deficiency. Moreover this model of cranial irradiation seems to be suitable to study the molecular mechanisms of radiation induced pubertal changes.

Effects of cancer therapy on dental and maxillofacial development in children: report of case

Malignant lymphoma is one of the most common hematological diseases of children. The prognosis is fairly good with multimodal cancer therapy. We reported a boy with Burkitt's lymphoma in the nasal cavity who received chemotherapy and irradiation of the head and neck area at four years of age. During seven years of follow-up, we studied the developmental effects of cancer therapy, including general growth, maxillofacial bones, and dentition. Compared with boys of matching age, the development of his entire body and maxillofacial bones was delayed. In the irradiated areas, the roots of teeth were short or poorly developed and the root apices showed premature closure. After the patient was in remission from the tumor in his early childhood, the long-term effects of cancer therapy on dental and maxillofacial development are worth our further evaluation and follow-up.

Effects of far-infrared ray on reproduction, growth, behaviour and some physiological parameters in mice

The effects of chronic exposure to far-infrared ray (FIR) on reproduction, growth, behaviour, survival time and some related parameters were examined in SHN mice. The reproductive parameters differed slightly between the females on the normal racks and those on the FIR racks, which emitted FIR from the ceiling. The age and body weight on the day of vaginal opening was lower in the experimental mice born and maintained on the FIR rack than in the control on the normal rack. In both sexes, the levels of urinary components in the experimental group was significantly higher than the control at 6-7 months of age. Spontaneous motor activity of females during the light and dark phases were higher and lower, respectively, in the experimental group than the control. The survival rate was significantly higher in the experimental group than the control. These findings suggest that FIR has 'normalization effects' on the organisms.

Adult height after growth hormone (GH) treatment for GH deficiency due to cranial irradiation

BACKGROUND

The indications and factors affecting the growth in response to treatment with growth hormone (GH) of patients with cranial irradiation-induced GH deficiency remain unclear.

PROCEDURE

The adult heights of 56 patients treated with GH (0.4-0.6 U/kg/week) as daily sc injections were analysed. They had been given 18 or 24 Grays (Gy) cranial irradiation for leukemia (group 1, 26 cases), 50 +/- 1 Gy for various tumors (group 2, 13 cases), 46 +/- 1 Gy for retinoblastoma (group 3, 8 cases), or 34 +/- 2 Gy with spinal irradiation for medulloblastoma (group 4, 9 cases). Twenty- five of these 56 patients had early puberty and were also treated with gonadotropin-releasing hormone (GnRH) analog.

RESULTS

The standing (-1.0 +/- 0.2 in group 1, -0.7 +/- 0.3 in group 2, -1.1 +/- 0.3 in group 3, and -2.0 +/- 0.4 SD in group 4) and sitting (-1.8 +/- 0.2 in group 1, -0.4 +/- 0.4 in group 2, -1.2 +/- 0.4 in group 3, and -3. 4 +/-0.4 SD in group 4) adult heights were shor ter (P < 0.05 for standing and P < 0.001 for sitting heights) for group 4 than for each of the other groups. Of the 47 patients given cranial (and not craniospinal) irradiation, sitting adult height was shorter (P = 0. 02) and the difference between standing adult and target heights greater (P = 0.03) in those patients in whom puberty occurred at a normal age than in those treated with GnRH analog. Conclusion. The incomplete catch-up of growth seems to be mainly due to the reduction in sitting height of patients given spinal irradiation and in whom puberty occurred at a normal age. This suggests that GnRH analog treatment should be more widely used to treat children with early and/or rapidly progressing puberty after cranial irradiation.

Dosimetry and growth hormone deficiency following cranial irradiation of childhood brain tumors

BACKGROUND

Dosimetry of the hypothalamus-pituitary (HP) region could allow prediction of the risk of growth hormone deficiency (GHD) following cranial irradiation.

PROCEDURE

Nineteen children (15 boys) with a median age of 6.3 years (range 1.7-16.5) at the time of irradiation of a brain tumor not involving the HP axis were followed for 1.2-6.3 years (median 3.4) from radiotherapy (RT). The dose to a standardized anatomical model including the HP region was calculated from dose-volume histograms of 10% to 100% in steps of 10% of the HP model based on data from a computer-based treatment planning system. If GHD was suspected from insulin-like growth factor-I, serum insulin-like growth factor binding protein-3, and/or height velocity measurements, an arginine stimulation test was performed. GHD was defined by a peak GH <15mU/liter.

RESULTS

Ten patients developed GHD 10-26 months from irradiation. Cox regression analysis identified the 90% dose-volume of the HP box as the strongest predictor of development of GHD (P = 0.03). The median dose to the 90% dose-volume of the HP region was 37.5 Gy (range 2. 3-55.3). The cumulated risk of GHD 2.5 years after radiotherapy for children receiving more than and less than 37.5 Gy to the HP region was 87% and 33%, respectively (P = 0.036).

CONCLUSIONS

Dosimetry of a defined HP volume provides the opportunity to 1) calculate the exact dose delivered to this region, 2) predict the risk of GHD and, 3) in the future revise the treatment planning and thus reduce the risk of endocrine adverse effects.

Growth in children with poor-risk neuroblastoma after regimens with or without total body irradiation in preparation for autologous bone marrow transplantation

Impaired growth after TBI prior to BMT has been a constant finding in children with leukemia. The growth of poor-risk neuroblastoma (NBL) survivors treated with myeloablative preparative regimens and ABMT at the Hospital for Children and Adolescents, University of Helsinki, since 1982 is reported. Two separate groups were analyzed: (1) The TBI- patients (n = 15) were conditioned with high-dose chemotherapy only. They had been treated at the age of 1.0-6.3 (mean 3.0) years and the post-ABMT follow-up time was 1.5-14.5 (mean 7.7) years. (2) The TBI+ patients (n = 16) had received TBI in addition to high-dose chemotherapy. They had been treated at the age of 1.3-4. 8 (mean 3.0) years, and the post-ABMT follow-up time was 1.5-8.0 (mean 4.7) years. The height standard deviation score (SDS) was similar for the two groups at the time of diagnosis, -0.3 +/- 1.2 (mean +/- s.d.), and at the time of ABMT, -0.7 +/- 1.1. After transplantation, the height SDS continued to decrease in the TBI+ group, the mean being -2.0 SDS at 5 years after ABMT. In the TBI-group, the mean height SDS remained within -0.7 to -0.9 to the 10 years of follow-up. Five patients received growth hormone (GH) therapy starting 2-6 years after ABMT. They all had low GH secretion in provocative tests. All showed some response to GH therapy. The mean height SDS increased 0.4 SDS during the 3 years following the start of GH therapy, while in the untreated patients a decrease of 0. 8 SDS during the corresponding time (P = 0.009) was observed. We conclude that NBL patients grow poorly following ABMT when TBI is included in the conditioning regimen, but close to normally when treated without TBI. The need for GH therapy should be evaluated early to avoid an unnecessary decrease in final height.

Changes in the pattern of growth in stature related to prenatal exposure to ionizing radiation

PURPOSE

To examine the pattern and spurt in growth and development of prenatally exposed atomic-bomb survivors and to determine whether a statistically significant radiation-related growth retardation exists.

MATERIALS AND METHODS

The stature of 1566 individuals exposed prenatally to the atomic bombings has been employed to study the effect of such exposure on growth. Among these survivors, 30 were severely mentally retarded, and 66 individuals on whom no physical measurements between ages 9 and 19 exist were excluded from this study. Thus this analysis rests on the measurements obtained on 1470 survivors 9 to 19 years of age at the time of examination.

RESULTS

When the > or =0.50 Sv group was compared to the other two prenatally exposed groups, a significant retardation of growth was observed only among those survivors exposed in the first trimester of gestation. The onset of the growth spurt among males in the three exposure groups was at approximately the same age, 11.34 years, but this was not true in females. The maximum velocity in growth for males was at 14.38 years of age, but for females no clear peak velocity was demonstrable.

CONCLUSION

A radiation-related growth retardation was demonstrable in this longitudinal study of the stature of individuals prenatally exposed. It is further demonstrated that among these survivors the growth velocity was faster in the high-dose group than in the low-dose group for both males and females.

[Biological effects of the low-intensive laser of the near infra-red spectrum]

The immediate and the remote effects of the total one-time uniform irradiation with arsenid-hallium laser (wavelength 0.89 mu, pulse power 450 W, pulsed mode 80-3000 Hz) on the new-born Wistar rats have been examined. The complex of tests illustrated the biotropical effects of used laser regimes. The stimulating or braking of the animal's growth was observed in accodanse with the laser regime.

Late complications of therapy in 213 children with localized, nonorbital soft-tissue sarcoma of the head and neck: A descriptive report from the Intergroup Rhabdomyosarcoma Studies (IRS)-II and - III. IRS Group of the Children's Cancer Group and the Pediatric Oncology Group

BACKGROUND

This review of children and adolescents with nonorbital soft-tissue sarcoma of the head and neck was undertaken to describe late sequelae of treatment, as manifested primarily by problems with statural growth, facial and nuchal symmetry, dentition, vision and hearing, and school performance.

PROCEDURE

Four hundred sixty-nine patients entered the IRS-II and -III protocols with localized, nonorbital soft-tissue sarcomas of the head and neck from 1978 through 1987. Their overall survival rate was 53% (250/469) at 5 years. Two hundred thirteen patients were surviving relapse-free 5 or more years after diagnosis, for whom there were serial height measurements at 2 or more years after initiation of therapy. Their median age at diagnosis was 5 years; the median length of follow-up was 7 years. All received multiple-agent chemotherapy, and all but 3 received irradiation to the primary tumor volume. Sixty-eight percent of the tumors arose in cranial parameningeal sites, 22% in nonparameningeal sites, and 10% in the neck. We reviewed flow sheets submitted to the IRS Group Statistical Office to ascertain which late sequelae were recorded.

RESULTS

One hundred sixty-four patients (77%) had one or more problems recorded. One hundred ninety of the two hundred thirteen patients (89%) were under 15 years of age at study entry, and at follow-up 92 (48%) had failed to maintain their initial height velocity, which had decreased by more than 25 percentile points from the original value. Thirty-six of the one hundred ninety patients (19%) were receiving growth hormone injections. Hypoplasia or asymmetry of tissues in the primary tumor site was reported in 74 patients, and 13 underwent reconstructive surgery. Poor dentition or malformed teeth were noted in 61 patients. Impaired vision developed in 37 patients, owing primarily to cataracts, corneal changes, and optic atrophy. Thirty-six patients had decreased hearing acuity, and 9 were fitted with hearing aids; 5 of these 9 had received cisplatin. Thirty-five patients were noted to have problems learning in school. Four patients developed a second malignancy (two sarcomas, one carcinoma, one leukemia).

CONCLUSIONS

Late sequelae affected the majority of these patients treated for soft-tissue sarcoma of the head and neck on IRS-II and -III. The potential impact of certain sequelae could be reduced by specific measures, such as surgical reconstruction and hormonal therapy. Late sequelae must be taken into account in designing future curative treatments.

Effects of total-body irradiation on growth, thyroid and pituitary gland in rhesus monkeys

PURPOSE

To investigate the effect of total-body irradiation (TBI) on growth, thyroid and pituitary gland in primates.

METHODS AND MATERIALS

Thirty-seven rhesus monkeys (mean age 3.1+/-0.6 years) received either a low-dose (4-6 Gy) TBI (n = 26) or high-dose (7-12 Gy) TBI (n = 11) and were sacrificed together with 8 age-matched controls after a post-irradiation interval of 5.9+/-1.5 years. Anthropometric data were collected: thyroid and pituitary glands were examined; serum levels of thyroid stimulating hormone (TSH), free thyroxin (FT4), insulin-like growth factor-I (IGF-I) and its binding protein-3 (IGFBP-3) were measured.

RESULTS

Decrease in final height due to irradiation could not be demonstrated. There was a dose-dependent decrease in body weight, ponderal index, skinfold thickness and thyroid weight. The latter was not accompanied by elevation of TSH or decrease in FT4. Structural changes in the thyroid gland were found in 50% of the irradiated animals. Levels of IGF-I and IGFBP-3 did not differ between the dose groups, but the high-dose group had a lower IGF-1/IGFBP-3 ratio.

CONCLUSION

Total body irradiation had a negative effect on body fat. There was no evidence of (compensated) hypothyroidism, but dose-dependent decrease in thyroid weight and changes in follicular structure suggest some effect of TBI on the thyroid gland. The decreased IGF-I/IGFBP-3 ratio in the high-dose group can indicate that the somatotrophic axis was mildly affected by TBI. These results show that TBI can have an effect on the physical build and thyroid gland of primates even in the absence of cytostatic agents or immunosuppressive drugs.

Growth failure after treatment of pediatric brain tumors

OBJECTIVES

Primary brain tumors are the most common solid tumors that occur in childhood. With improved management of these tumors, there are more survivors with long-term sequelae of radiation and chemotherapy including growth failure. The aim of this study was to assess growth prospectively in children with nonpituitary-related primary brain tumors.

METHODS

Forty-one children 3.1 to 13.8 years of age diagnosed consecutively between 1989 and 1992 with a primary nonpituitary-related brain tumor were studied.

RESULTS

Of 34 prepubertal children, 14 (41%) were diagnosed as having growth hormone (GH) deficiency. All 14 children were treated with cranial irradiation. During the first year from completion of brain tumor therapy, the annual height velocity of those children confirmed subsequently as being GH-deficient was 3.06 +/- 1.19 cm compared with 5.29 +/- 2.21 cm for those who were not GH-deficient. During the second year, the annual height velocity was 3.29 +/- 1.14 cm per year for the GH-deficient group compared with 5.48 +/- 1.24 cm per year for the non-GH-deficient group. All children with GH deficiency received cranial irradiation and chemotherapy. Two of 34 children developed precocious puberty. Primary hypothyroidism was diagnosed in 6 of 41 children (12%).

CONCLUSION

We conclude that GH deficiency and primary hypothyroidism are common after cranial irradiation and chemotherapy for nonpituitary-related brain tumors. Linear growth appears to reflect GH status accurately in children with brain tumors. Precise auxologic evaluation is simple and noninvasive and may reflect more accurately GH status than provocative GH testing. These findings reflect the need for prospective growth monitoring of children with nonpituitary-related brain tumors treated with cranial irradiation and chemotherapy. Early diagnosis of GH deficiency facilitates early initiation of GH therapy and optimization of final height.

Radiation-related brain damage and growth retardation among the prenatally exposed atomic bomb survivors

Many studies of prenatally exposed survivors of the atomic bombings of Hiroshima and Nagasaki have shown that exposure to ionizing radiation during gestation has harmful effects on the developing human brain. Data on the occurrence of severe mental retardation as well as variation in intelligence quotient (IQ) and school performance show significant effects on those survivors exposed 8-15 and 16-25 weeks after ovulation. Studies of seizures, especially those without a known precipitating cause, also exhibit a radiation effect in survivors exposed 8-15 weeks after ovulation. The biologic events that subtend these abnormalities are still unclear. However, magnetic resonance imaging of the brains of some mentally retarded survivors has revealed a large region of abnormally situated gray matter, suggesting an abnormality in neuronal migration. Radiation can induce small head size as well as mental retardation, and a review of the relationship between small head size and anthropometric measurements, such as height, weight, sitting height and chest circumference, shows that individuals with small head size have smaller anthropometric measurements than normocephalics. This suggests that radiation-related small head size is related to a generalized growth retardation. Finally, the issue of a threshold in the occurrence of one or more of these effects, both heuristically and from a regulatory perspective, remains uncertain. Simple inspection of the data often suggests that a threshold may exist, but little statistical support for this impression can be advanced, except in the instance of mental retardation.

Final height and weight of long-term survivors of childhood malignancies

The aim of this study was to investigate growth and final height in young adults after therapy for malignant diseases. Final height and weight was studied in 50 long-term survivors (LTS) of childhood cancer (aged 17-31 years; 30 men, 20 women) 3-18 years after treatment for malignant diseases (7 acute lymphoblastic leukemia, 20 lymphoma, 8 sarcoma, 15 malignant central nervous system [CNS] tumours). None of the LTS had been treated with growth hormone (GH). A decrease in final height SDS (Standard deviation score) occurred in both LTS of malignant CNS tumours (median height SDS at diagnosis, 0.3; range, -0.9 to 2.2; median final height SDS, -1.3; range, -3.9 to 1.9; p < 0.01) and LTS of lymphoma (p < 0.05) or leukemia (p < 0.05). However, only LTS who received cranial (p < 0.05) or craniospinal (p < 0.001) irradiation (XRT) exhibited reduced final heights. LTS who had received XRT not involving the CNS or had received no XRT at all presented no reduction in final height. LTS of CNS tumours treated with high craniospinal XRT doses (24 to 56 Gy) reached lower (p < 0.01) final heights when compared with LTS of leukemia who received lower cranial XRT doses (18 to 24 Gy). Final height SDS correlated with chronological age at initiation of therapy (p < 0.05). No correlation was found between the cumulative doses of applied chemotherapeutic agents and the final height of LTS. During follow-up LTS developed an increase in weight for height index (WFH) which occurred independent of XRT. In conclusion, cranial and craniospinal XRT especially in young children with malignancies resulted in a decrease in final height SDS. As 6 of 15 LTS of malignant CNS tumours exhibited a final height SDS below -2 SD, analysis of pituitary function and substitution of GH after diagnosis of GH deficiency should be considered for these patients at a young age. Others factors not directly related to XRT are responsible for the increased risk for obesity in LTS of childhood cancer.

[Treatment of acute lymphocytic leukemia and growth]

BACKGROUND

The treatment of the acute lymphocytic leukaemia can determine impaired growth.

SUBJECTS AND METHOD

All the patients had length measurements at the time of the beginning of the treatment and, at least, one year after the end of it.

CONCLUSIONS

There was impaired growth after the treatment according to the dose regimens (18 or 24 Grays). No relation was observed related to the age at the diagnosis.

Hypersensitivity of Ku80-deficient cell lines and mice to DNA damage: the effects of ionizing radiation on growth, survival, and development

We recently have shown that mice deficient for the 86-kDa component (Ku80) of the DNA-dependent protein kinase exhibit growth retardation and a profound deficiency in V(D)J (variable, diversity, and joining) recombination. These defects may be related to abnormalities in DNA metabolism that arise from the inability of Ku80 mutant cells to process DNA double-strand breaks. To further characterize the role of Ku80 in DNA double-strand break repair, we have generated embryonic stem cells and pre-B cells and examined their response to ionizing radiation. Ku80(-/-) embryonic stem cells are more sensitive than controls to gamma-irradiation, and pre-B cells derived from Ku80 mutant mice display enhanced spontaneous and gamma-ray-induced apoptosis. We then determined the effects of ionizing radiation on the survival, growth, and lymphocyte development in Ku80-deficient mice. Ku80(-/-) mice display a hypersensitivity to gamma-irradiation, characterized by loss of hair pigmentation, severe injury to the gastrointestinal tract, and enhanced mortality. Exposure of newborn Ku80(-/-) mice to sublethal doses of ionizing radiation enhances their growth retardation and results in the induction of T cell-specific differentiation. However, unlike severe combined immunodeficient mice, radiation-induced T cell development in Ku80(-/-) mice is not accompanied by extensive thymocyte proliferation. The response of Ku80-deficient cell lines and mice to DNA-damaging agents provides important insights into the role of Ku80 in growth regulation, lymphocyte development, and DNA repair.

Potential role of proton therapy in the treatment of pediatric medulloblastoma/primitive neuro-ectodermal tumors: spinal theca irradiation

PURPOSE

Conventional postoperative photon-beam radiotherapy to the spine in children with medulloblastoma/PNET is associated with severe late effects. This morbidity (growth and developmental) is related to the exit dose of the beams and is particularly severe in young children. With the purpose of reducing this toxicity, a dosimetric study was undertaken in which proton therapy was compared to standard megavoltage photon treatment.

METHODS AND MATERIALS

The results of a comparative dosimetric study are presented in such a way that the dose distribution achievable with a posterior modulated 100 MeV proton beam (spot scanning method) is compared with that of a standard set of posterior 6 MV x-ray fields. The potential improvements with protons are evaluated, using dose-volume histograms to examine the coverage of the target as well as the dose to the vertebral bodies (growth plates), lungs, heart, and liver.

RESULTS

The target (i.e., the spinal dural sac) received the full prescribed dose in both treatment plans. However, the proportions of the vertebral body volume receiving > or = 50% of the prescribed dose were 100 and 20% for 6 MV x-rays and protons, respectively. For 6 MV x-rays > 60% of the dose prescribed to the target was delivered to 44% of the heart volume, while the proton beam was able to completely avoid the heart, the liver, and in all likelihood the thyroid and gonads as well.

CONCLUSION

The present study demonstrates a potential role of proton therapy in decreasing the dose (and toxicity) to the critical structures in the irradiation of the spinal neuraxis in medulloblastoma/PNET. The potential bone marrow and growth arrest sparing effects make this approach specially attractive for intensive chemotherapy protocols and for very young children. Sparing the thyroid gland, the posterior heart wall, and the gonads may be additional advantages in assuring a long-term posttreatment morbidity-free survival.

Late effects of allogeneic bone marrow transplantation for children with acute myeloblastic leukemia in first complete remission: the impact of conditioning regimen without total-body irradiation--a report from the Société Française de Greffe de Moelle

PURPOSE

To evaluate growth, thyroid function, puberty, cardiac function, and the incidence of cataracts in children who received allogeneic bone marrow transplantation (BMT) for acute myeloblastic leukemia (AML) in first complete remission (CR) after a preparation with or without total-body irradiation (TBI).

PATIENTS AND METHODS

Among 45 children studied, 26 received busulfan-cyclophosphamide (Bu-Cy) in preparation for transplantation and 19 received TBI. TBI was fractionated in nine cases and delivered as a single dose in 10. Four children in the Bu-Cy group and none in the TBI group had received prior cranial radiation. The mean follow-up duration after BMT was 5.9 years for the whole group.

RESULTS

The mean cumulative changes in height SD score (SDS) were -0.86 at 3 years and -1.56 at 5 years in the TBI group, whereas these changes were only -0.05 and -0.17 in the Bu-Cy group (P < .01 at 3 and 5 years). The 6-year probability of hypothyroidism was 9% +/- 8% in the Bu-Cy group and 43% +/- 15% after TBI (P < .02). Pubertal development after Bu-Cy was assessable in two girls and five boys: both girls had primary ovarian failure, whereas Leydig cell function appeared to be preserved in the five boys. One child who had received anthracycline when he was less than 1 year old developed cardiac dysfunction 4 years after Bu-Cy. The 6-year probability of cataracts was 70% +/- 13% in the TBI group and 0% after Bu-Cy.

CONCLUSION

The use of Bu-Cy represents an alternative transplant cytoreductive regimen for children with AML in first CR, which can reduce the risk of posttransplant growth impairment, thyroid dysfunction, Leydig cell damage, and the incidence of cataracts.

[Late sequelae of comprehensive antineoplastic therapy in children and adolescents with solid extracranial tumors. Effect on growth, pubertal development and gonadal function]

BACKGROUND

Modern treatment of oncological diseases increases markedly the chance of long-term survival and permanent recovery. Due to frequently highly aggressive treatment it is however associated with the risk of late sequelae in the surviving patients. Comprehensive care of patients includes therefore not only control of the neoplastic disease but also efforts of maximal improvement of the quality of life of the patients. In young subjects, in view of their long-term perspective, this problem is particularly important.

METHODS AND RESULTS

In 32 patients (25 boys and 7 girls) with extracranial solid tumours without primary endocrinological symptomatology (m. Hodgkin, neuroblastoma, ganglioneuroblastoma, nephroblastoma, Ewings sarcoma and others) a single examination was made assessing height, body weight, grade of sexual maturation according to Tanner, in boys testicular volume by means of a orchidometer and 20 other anthropometric dimensions. The mean age at the time of examination was 16.5 +/- 4.1 years, the mean age at the onset of treatment 6.1 +/- 4.8 years. The patients height, -0.4 +/- 0.9 SD, differs from the Czech national standard (p = 0.025). Impaired growth was recorded in 12.5% patients and had heterogenous causes. The authors proved a negative effect of radiotherapy on the growth of the spine, most markedly in children subjected to irradiation of the abdomen and chest and a highly significant reduction of the testicular volume in boys after cytostatic treatment of m. Hodgkin.

CONCLUSIONS

The results are consistent with studies made abroad and indicate the necessity of comprehensive long-term follow-up of somatic growth and development of the gonads in oncological child patients.

Toxicity of CNS prophylaxis for childhood leukemia

Long-term neurotoxicity associated with central nervous system (CNS) prophylaxis for childhood acute lymphoblastic leukemia (ALL), primarily involving physical growth and cognitive development, is an ongoing concern. Although contemporary treatment protocols are associated with less severe toxicity than was commonly observed with earlier protocols, there continue to be late effects. When treatment includes cranial radiation therapy (CRT), linear growth is likely to be impaired. Female patients are more vulnerable to late cognitive effects than male patients, particularly when treated with CRT and high doses of methotrexate. Young age at treatment is a risk factor as well, particularly for girls. In order to treat medical and psychological problems early, a commitment to long-term follow-up is essential.

[Growth and puberty in children after treatment of acute lymphoblastic leukemia]

BACKGROUND

Growth retardation and other endocrine abnormalities were recognized as sequelae of therapy of acute lymphoblastic leukemia (ALL), especially when chemotherapy was combined with cranial irradiation. The aim of our study was to establish growth and pubertal development in the group of children who had been previously successfully treated for ALL.

METHODS AND RESULTS

58 children (30 F, 28 M, age 8-18 y.) in complete initial remission lasting 4-15 y. (m 8 y.) after standard antileukemic therapy (including cranial irradiation) completed 2-9 y. ago (m 3 including y.) were studied. Standard deviation score (SDS) of standing height (SH) to chronological age (CA) and to genetic target height (GTH), index of body proportionality and timing of puberty were followed up. The final height attained 21 girls and 3 boys. The height of the boys differed neither from the average for our men, nor from their GTH. Girls: SH 148 cm-169 cm, SH of 7 girls > or = -1.5 SDS, 8 girls > or = -1.5 SDS to their GTH. The final height didn't reach yet 23 boys and 9 girls. Their SH to CA as well as SH to GTH didn't substantially differ from average. Index of body proportionality > or = 1.5 SDS in 12/30 girls and 6/28 boys. Menarche was already reached in 25 girls in age ranging from 10-15 y. (mean 11.3 y.), what was less than average for our population (13.3 y.).

CONCLUSION

Even the height of prepubertal children under study didn't differ from average, the final height of girls (boys could not be evaluated because of small numbers) was significantly lower as could be expected. We suppose the early ending of puberty as a contributing factor of short stature in girls. Clear tendency to obesity especially among older girls was observed. Children who underwent antileukemic therapy deserve careful endocrinological follow-up.

The pef mutants of Arabidopsis thaliana define lesions early in the phytochrome signaling pathway

In a screen for early-flowering mutants, a number of mutants that were early flowering under both short and long days were isolated. One such mutant, pef1, was selectively insensitive to both red and far-red light in the inhibition of hypocotyl elongation response; a classic phytochrome phenotype mediated by both PHYA and PHYB. The pef1 mutant seedlings could not be phenotypically rescued by biliverdin, a precursor of the phytochrome chromophore, nor did they fail to complement any previously identified elongated hypocotyl (hy) mutants. Difference spectra and Western blot analysis showed normal concentrations of PHYA photoreceptor apoprotein, which appeared photochemically active. It was concluded that the pef1 mutant is defective in both PHYA- and PHYB-mediated signaling pathways, and may represent a lesion in an early step of the phytochrome signal transduction pathway. Additional pef mutants deficient specifically in PHYB-mediated responses were also identified by this screen.

Neurobehavioral study of prenatal exposure to hyperthermia combined with irradiation in mice

Thirty-two pregnant adult LACA mice were randomly assigned to one of five exposure groups: control, 38 degrees C, 42 degrees C, irradiation, and 42 degrees C + irradiation. Animals were exposed on gestation day 9 to either 38 degrees C waterbath for 5 min, 42 degrees C waterbath for 5 min, treatment with 0.5 Gy of 60Co gamma irradiation, or pretreatment at 42 degrees C waterbath for 5 min following by 0.5 Gy of 60CO gamma irradiation. On postnatal day 7, litters were reduced to a maximum of eight pups per litter, with equal members of male and female offspring whenever possible. A total of 216 pups were observed for the age of acquisition of four physiological landmarks (pinna detachment, incisor eruption, eye opening, testes descent), six developmental reflexes (surface righting, cliff avoidance, auditory startle, air righting, visual placing, hindlimb splaying), and examination of learning and memory function. These studies, at threshold exposure levels to hyperthermia and ionizing radiation, indicate there is no consistent significant additional postnatal effect when pregnant mice are exposed to both of these agents. These studies are important for our understanding of the relative long-range effects of prenatal exposure to hyperthermia and acute dose irradiation early in gestation on neurobehavioral teratogenesis.

The effects of irradiation and chemotherapy on growth

The effects of cancer therapy on growth are reviewed. The effects of radiation and chemotherapy on growth hormone production and growth hormone responsiveness by peripheral tissues are examined. The effects of radiotherapy and chemotherapy on other endocrine function pertaining to growth also are discussed. An approach to surveillance of pediatric cancer survivors pertaining to growth and development is suggested.