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1.
J Musculoskelet Neuronal Interact ; 16(3): 183-92, 2016 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-27609033

RESUMO

OBJECTIVES: to investigate feasibility, safety and efficacy of home-based side-alternating whole body vibration (sWBV) to improve motor function in toddlers with cerebral palsy (CP). METHODS: Randomized controlled trial including 24 toddlers with CP (mean age 19 months (SD±3.1); 13 boys). INTERVENTION: 14 weeks sWBV with ten 9-minute sessions weekly (non-individualized). Group A started with sWBV, followed by 14 weeks without; in group B this order was reversed. Feasibility (≥70% adherence) and adverse events were recorded; efficacy evaluated with the Gross Motor Function Measure (GMFM-66), Pediatric Evaluation of Disability Inventory (PEDI), at baseline (T0), 14 (T1) and 28 weeks (T2). RESULTS: Developmental change between T0 and T1 was similar in both groups; change scores in group A and B: GMFM-66 2.4 (SD±2.1) and 3.3 (SD±2.9) (p=0.412); PEDI mobility 8.4 (SD±6.6) and 3.5 (SD±9.2) (p=0.148), respectively. In two children muscle tone increased post-sWBV. 24 children received between 67 and 140 sWBV sessions, rate of completed sessions ranged from 48 to 100% and no dropouts were observed. CONCLUSION: A 14-week home-based sWBV intervention was feasible and safe in toddlers with CP, but was not associated with improvement in gross motor function.


Assuntos
Paralisia Cerebral/reabilitação , Modalidades de Fisioterapia , Vibração/uso terapêutico , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Modalidades de Fisioterapia/instrumentação , Projetos Piloto , Vibração/efeitos adversos
2.
Ophthalmologe ; 113(7): 557-69, 2016 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-27352283

RESUMO

Pediatric oncology has achieved major progress by continuous optimization of diagnostic and therapeutic approaches. In the interdisciplinary team, the ophthalmologist plays an important role. In the field of strabismus and neuro-ophthalmology clinical symptoms as strabismus, visual loss, anisocoria, visual field defects, and involuntary eye movements may be key indicators of childhood cancer. The appropriate diagnostic workup as well as the diagnostic and therapeutic steps during the course of the disease are important often requiring individually tailored approaches.


Assuntos
Anisocoria/etiologia , Neoplasias/complicações , Neoplasias/terapia , Estrabismo/etiologia , Estrabismo/terapia , Transtornos da Visão/etiologia , Transtornos da Visão/terapia , Adolescente , Anisocoria/diagnóstico , Anisocoria/terapia , Criança , Pré-Escolar , Diagnóstico Diferencial , Humanos , Lactente , Comunicação Interdisciplinar , Colaboração Intersetorial , Neoplasias/diagnóstico , Estrabismo/diagnóstico , Transtornos da Visão/diagnóstico , Campos Visuais
3.
Graefes Arch Clin Exp Ophthalmol ; 253(12): 2239-46, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26464178

RESUMO

BACKGROUND: Leber congenital amaurosis (LCA) is a severe retinal dystrophy, typically manifesting in the first year of life. Mutations in more than 18 genes have been reported to date. In recent studies, biallelic mutations in NMNAT1 encoding nicotinamide mononucleotide adenylyltransferase 1 have been found to cause LCA. PURPOSE: To broaden the knowledge regarding the phenotype of NMNAT1-associated LCA. METHODS: Clinical ophthalmologic examinations were performed in two sisters with LCA. Whole exome sequencing was performed in one of the affected girls, with subsequent segregation analysis in the affected sister and unaffected parents. The literature was reviewed for reports of NMNAT1-associated LCA. RESULTS: Exome sequencing revealed the known NMNAT1 mutation c.25G>A (p.Val9Met) in a homozygous state. Segregation analysis showed the same homozygous mutation in the affected younger sister. Both parents were found to be heterozygous carriers of the mutation. The two girls both presented with severe visual impairment, nystagmus, central atrophy of the pigment epithelium, and pigment clumping in the periphery before the age of 6 months. Retinal vessels were attenuated. Both children were hyperopic. In the older sister, differential diagnosis included an inflammatory origin, but electrophysiology in her as well as her sister confirmed a diagnosis of LCA. Pallor of the optic nerve head was not present at birth but developed progressively. CONCLUSIONS: We confirmed a diagnosis of NMNAT1-associated LCA in two siblings through identification of the mutation (c.25G>A [p. Val9Met]) in a homozygous state. In infants with non-detectable electroretinogram (ERG), along with severe congenital visual dysfunction or blindness and central pigment epithelium atrophy with pigment clumping resembling scarring due to chorioretinitis, LCA due to NMNAT1 mutations should be considered.


Assuntos
Amaurose Congênita de Leber/genética , Mutação de Sentido Incorreto , Nicotinamida-Nucleotídeo Adenililtransferase/genética , Sequência de Bases , Cegueira/diagnóstico , Cegueira/genética , Cegueira/fisiopatologia , Criança , Pré-Escolar , Consanguinidade , Análise Mutacional de DNA , Eletrorretinografia , Potenciais Evocados Visuais/fisiologia , Exoma/genética , Feminino , Humanos , Amaurose Congênita de Leber/diagnóstico , Amaurose Congênita de Leber/fisiopatologia , Dados de Sequência Molecular , Linhagem , Tomografia de Coerência Óptica , Acuidade Visual/fisiologia
4.
Klin Padiatr ; 223(1): 10-4, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21271514

RESUMO

BACKGROUND: During a period of 12 months 7 newborns with a partially severe fetopathy caused most probably by maternal sartan-intake in pregnancy were treated in 5 German teaching hospitals. Sartans antagonize the effect of angiotensin II at the AT1-receptor and are used to treat arterial hypertension. METHOD: We presented 2 cases at the yearly GNPI meeting 2010 and we were informed about similar cases in other German teaching hospitals which we brought together in this publication. RESULTS: In the presented cases, maternal sartan intake was noticed at different times in pregnancy and was in part discontinued some weeks before delivery. In all pregnancies oligohydramnios was present and fetal kidneys displayed a hyperechogenic structure on ultrasound. The newborns' postnatal course varied: oligohydramnios sequence with lung hypoplasia, arterial hypotension and renal insufficiency were the predominant problems of the first days of life. The majority (4/7) of infants did not survive this period, in other cases there was a complete (1/7) recovery of renal function whereas others survived with renal impairment (2/7), in part requiring chronic dialysis. Further distinctive features seen frequently were disturbances of cranial ossification and flaccid paralysis of hands and feet with deviations as well as sensorineural hearing loss. CONCLUSION: These case reports again underline the hazardousness of maternal sartan intake with potential fatal outcome for the newborn. Though the use of sartans in pregnancy is contraindicated and several case reports of sartan induced fetopathies exist, the risk of sartan treatment generally seems to be underestimated.


Assuntos
Anormalidades Induzidas por Medicamentos/etiologia , Bloqueadores do Receptor Tipo 1 de Angiotensina II/toxicidade , Anti-Hipertensivos/toxicidade , Hipertensão Induzida pela Gravidez/tratamento farmacológico , Anormalidades Induzidas por Medicamentos/diagnóstico , Anormalidades Induzidas por Medicamentos/patologia , Adulto , Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Anti-Hipertensivos/uso terapêutico , Índice de Apgar , Benzimidazóis/uso terapêutico , Benzimidazóis/toxicidade , Compostos de Bifenilo , Feminino , Retardo do Crescimento Fetal/induzido quimicamente , Retardo do Crescimento Fetal/diagnóstico , Retardo do Crescimento Fetal/patologia , Humanos , Hipertensão Pulmonar/induzido quimicamente , Hipertensão Pulmonar/diagnóstico , Hipertensão Pulmonar/patologia , Imidazóis/uso terapêutico , Imidazóis/toxicidade , Recém-Nascido , Rim/anormalidades , Rim/efeitos dos fármacos , Rim/patologia , Pulmão/anormalidades , Pulmão/efeitos dos fármacos , Pulmão/patologia , Masculino , Oligo-Hidrâmnio/induzido quimicamente , Gravidez , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Insuficiência Renal/induzido quimicamente , Insuficiência Renal/diagnóstico , Insuficiência Renal/patologia , Crânio/anormalidades , Crânio/efeitos dos fármacos , Crânio/patologia , Tetrazóis/uso terapêutico , Tetrazóis/toxicidade , Ultrassonografia Pré-Natal , Valina/análogos & derivados , Valina/uso terapêutico , Valina/toxicidade , Valsartana
5.
Klin Monbl Augenheilkd ; 227(10): 786-91, 2010 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-20963681

RESUMO

BACKGROUND: Joubert syndrome (JS) belongs to the ciliopathies and is a mostly autosomal recessively inherited disease (in the case of OFD1 mutations, JS is an X-linked trait). It is characterised by midbrain-hindbrain malformations with developmental delay, hypotonia and ataxia and a broad spectrum of other facultative findings. The aim of our study was to examine the ophthalmological and neuro-ophthalmological features of JS in our patients and to compare our findings to those of other studies. METHODS: In a retrospective study we evaluated the ophthalmological and neuro-ophthalmological findings of 9 consecutive patients who met the diagnostic criteria of JS. RESULTS: All patients had abnormalities of ocular motility, 4/9 used head thrusts to shift gaze (oculomotor apraxia OMA). In 6/8 patients, the optokinetic reflex (OKN) was absent. Furthermore, 8/9 children showed nystagmus, mostly see-saw nystagmus. Manifest strabismus was found in 8/9 while 3/9 had a retinopathy with either abnormal ERG and/or fundus appearance with or without visual impairment. Chorioretinal colobomata were present in 5/9 cases. Two patients showed a unilateral congenital ptosis, one a facial nerve paresis. CONCLUSIONS: The early neuro-ophthalmological findings in JS are not pathognonomic, but may lead to the diagnosis of JS. The syndrome should be suspected in patients with nystagmus, especially see-saw nystagmus, and abnormal OKN and/or OMA, and/or colobomata of the fundus, and further paediatric examinations should be initiated.


Assuntos
Doenças Cerebelares , Coloboma , Doenças Renais Policísticas , Proteínas Adaptadoras de Transdução de Sinal/genética , Adolescente , Ambliopia/diagnóstico , Ambliopia/genética , Antígenos de Neoplasias/genética , Blefaroptose/diagnóstico , Blefaroptose/genética , Tronco Encefálico/anormalidades , Tronco Encefálico/patologia , Proteínas de Ciclo Celular , Doenças Cerebelares/classificação , Doenças Cerebelares/diagnóstico , Doenças Cerebelares/genética , Cerebelo/anormalidades , Cerebelo/patologia , Criança , Pré-Escolar , Coloboma/classificação , Coloboma/diagnóstico , Coloboma/genética , Consanguinidade , Proteínas do Citoesqueleto , Análise Mutacional de DNA , Eletrorretinografia , Paralisia Facial/diagnóstico , Paralisia Facial/genética , Feminino , Fundo de Olho , Humanos , Imageamento por Ressonância Magnética , Masculino , Proteínas de Membrana/genética , Proteínas de Neoplasias/genética , Nistagmo Optocinético/genética , Transtornos da Motilidade Ocular/diagnóstico , Transtornos da Motilidade Ocular/genética , Doenças Renais Policísticas/classificação , Doenças Renais Policísticas/diagnóstico , Doenças Renais Policísticas/genética , Refração Ocular , Estudos Retrospectivos , Estrabismo/diagnóstico , Estrabismo/genética , Acuidade Visual , Adulto Jovem
6.
Neonatology ; 94(2): 71-4, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18196929

RESUMO

BACKGROUND: A high percentage of preterm neonates are born small for gestational age (SGA). These children show a high morbidity and mortality after birth and often develop insulin resistance with ensuing impaired glucose metabolism in adulthood. Since insulin is important for intrauterine growth, fetal insulin resistance might also influence birth weight of preterm neonates. OBJECTIVES: A common polymorphism in the promoter region of the human hepatic glucokinase (-258) is associated with a decreased promoter activity, an enhanced insulin secretion, and hypertension and hepatic insulin resistance in adults. In this pilot study we wanted to investigate whether the G/A polymorphism at -258 of the hepatic glucokinase promoter has an effect on birth weight of preterm neonates and therefore might constitute a genotype leading to low birth weight and metabolic defects. METHODS: We enrolled 106 preterm neonates in our study. 44 of them were SGA and 62 AGA neonates. We extracted DNA from a buccal swab and identified the polymorphism by PCR-ARMS. RESULTS: We found no difference in the prevalence of the polymorphism in either groups. CONCLUSION: The polymorphism at -258 of the fetal hepatic glucokinase promoter is most probably not of a major relevance in the pathophysiology of low birth weight in preterm neonates.


Assuntos
Peso ao Nascer/genética , Predisposição Genética para Doença , Glucoquinase/genética , Recém-Nascido Pequeno para a Idade Gestacional/fisiologia , Fígado/enzimologia , Polimorfismo de Nucleotídeo Único/genética , Análise Mutacional de DNA , Feminino , Genótipo , Glucoquinase/metabolismo , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Resistência à Insulina/genética , Masculino , Projetos Piloto , Regiões Promotoras Genéticas
7.
Nervenarzt ; 73(8): 774-8, 2002 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-12242967

RESUMO

Ten to twenty percent of the offspring of mothers suffering from myasthenia gravis (MG) also develop transient neonatal MG, since maternal antibodies are able to cross the placenta. We report the course of two newborns of a mother with MG and a healthy father. The first pregnancy was complicated during the 3rd trimester by a hydramnion. The newborn presented with generalized muscle weakness, respiratory distress, weak sounding, anaemia, and poor sucking. Mechanical ventilation was necessary. Confirmation of the diagnosis was achieved by the result of repetitive muscle stimulation, showing a typical decrement in the EMG, and measurement of serum antiacetylcholin receptor antibodies. For 3 months, the infant was treated with neostigmin (cholinesterase inhibitor). After 26 days of hospitalization, the patient was released and followed up regularly. Myasthenic symptoms completely resolved. Side effects of the treatment were not observed. The course of the second pregnancy was normal. This second newborn was healthy. Our case report is remarkable for the very different presentation of two children of the same mother with MG during pregnancy and after delivery, with one child developing severe transient neonatal MG, initially requiring intensive care unit (ICU) treatment followed by quick recovery, and one child being healthy. We also present a score for monitoring the clinical course and adjusting anticholinesterase therapy accordingly.


Assuntos
Síndromes Miastênicas Congênitas/diagnóstico , Neostigmina/uso terapêutico , Adulto , Terapia Combinada , Feminino , Seguimentos , Humanos , Recém-Nascido , Terapia Intensiva Neonatal , Síndromes Miastênicas Congênitas/terapia , Exame Neurológico/efeitos dos fármacos , Gravidez , Diagnóstico Pré-Natal , Respiração Artificial
8.
Pediatrics ; 108(6): E107, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11731634

RESUMO

OBJECTIVE: To examine bone development in children and adolescents who have uncomplicated idiopathic epilepsy and had received monotherapy with carbamazepine or valproic acid for at least 1 year. METHODS: Thirty-nine patients from 6 to 19 years of age (18 girls) were studied. Total bone mineral content (BMC) and trabecular volumetric bone mineral density were measured at the distal radius using peripheral quantitative computed tomography. Maximum isometric grip force was determined with a standard dynamometer. Alkaline phosphatase activity and deoxypyridinoline (a marker of bone resorption) were assessed in serum and urine, respectively. RESULTS: Trabecular volumetric bone mineral density was significantly decreased in the entire group (z score mean +/- standard deviation: -0.62 +/- 1.04) and in the subgroup using valproic acid (-0.75 +/- 1.18). In the carbamazepine subgroup, there was a similar but nonsignificant trend (-0.50 +/- 0.90). Total BMC and isometric maximum grip force were normal in the entire study population (0.10 +/- 1.22) and in the 2 subgroups. The relationship between BMC and grip force was similar between patients and healthy participants. Urinary levels of deoxypyridinoline were significantly elevated above normal in the whole study population (1.35 +/- 2.00) and in both the valproic acid and the carbamazepine subgroups. CONCLUSIONS: Bone turnover can be increased, but bone mass is adequate in children and adolescents who have uncomplicated idiopathic epilepsy and who receive monotherapy with carbamazepine or valproic acid.


Assuntos
Anticonvulsivantes/farmacologia , Carbamazepina/farmacologia , Sistema Musculoesquelético/efeitos dos fármacos , Ácido Valproico/farmacologia , Adolescente , Fosfatase Alcalina/metabolismo , Aminoácidos/metabolismo , Anticonvulsivantes/uso terapêutico , Biomarcadores , Densidade Óssea/efeitos dos fármacos , Reabsorção Óssea , Carbamazepina/uso terapêutico , Criança , Estudos Transversais , Epilepsia/tratamento farmacológico , Força da Mão , Humanos , Análise de Regressão , Ácido Valproico/uso terapêutico
9.
J Clin Densitom ; 4(3): 257-62, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11791503

RESUMO

We compared the results of peripheral quantitative computed tomography (pQCT) measurements (XCT-900; Stratec) at the 4% site of the distal radius (section 1; slice thickness of 2 mm) and in two proximally adjacent sections (sections 2 and 3). The study population consisted of 138 ambulatory patients (age 16.4 +/- 5.6 yr; mean +/- SD; 71 female) who were referred to a pediatric densitometry unit. Total volumetric bone mineral density (BMD) increased, whereas the area of the radial cross-section decreased in a proximal direction. There was a decrease in bone mineral content between sections 1 and 3, which was more pronounced in subjects under age 16. Cancellous BMD significantly decreased from section 1 to 3 only under the age of 16. In 12 patients under age 17 who suffered from increased bone fragility, cancellous BMD decreased about 2.5 times more between sections 1 and 3 than in age-matched patients who received anticonvulsant therapy but had a normal neurologic and musculoskeletal status (-21.4% +/- 16.9 vs -8.1% +/- 6.3; p = 0.02). This suggests that in the bone fragility group, trabeculae were removed faster during longitudinal growth of the radius. In conclusion, multiple slice analysis may provide information on the dynamic turnover of metaphyseal trabeculae during growth.


Assuntos
Remodelação Óssea , Rádio (Anatomia)/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adolescente , Adulto , Fatores Etários , Densidade Óssea/efeitos dos fármacos , Desenvolvimento Ósseo , Doenças Ósseas/diagnóstico , Criança , Feminino , Fraturas Ósseas/metabolismo , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Rádio (Anatomia)/fisiologia
10.
J Pediatr Surg ; 34(12): 1872-3, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10626878

RESUMO

Sternoclavicular (SC) dislocation is an injury that is very rare in the newborn. Thus far there have been no reports describing this in neonates after a traumatic birth injury. This condition can be difficult to differentiate from epiphyseal separation, which occurs more often in older children. For successful treatment, early diagnosis is essential. Timely surgical reposition and fixation with following immobilization is recommended in instances of complete (SC) dislocation. We report a trauma-induced case of SC dislocation in a neonate successfully managed by polydioxanon cord fixation.


Assuntos
Traumatismos do Nascimento , Luxações Articulares/etiologia , Articulação Esternoclavicular/lesões , Traumatismos do Nascimento/cirurgia , Humanos , Recém-Nascido , Luxações Articulares/cirurgia , Articulação Esternoclavicular/cirurgia
11.
Eur J Pediatr ; 156(10): 789-91, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9365070

RESUMO

UNLABELLED: Schimke immuno-osseous dysplasia is a multisystem disorder consisting of spondylo-epiphysial dysplasia, progressive renal insufficiency due to focal segmental glomerulosclerosis, and immunodeficiency. Cerebrovascular complications have only been described in five patients. Here we report a patient with prominent neurological symptoms most likely caused by transient ischaemic attacks. CONCLUSION: Neurological symptoms consisted of repeated brief spells of hemiparaesthesia, motoric aphasia and diplopia. MRI studies of the CNS revealed progressive white matter lesions. Morphological changes as well as neurological deficits are compatible with cerebral ischaemia.


Assuntos
Nanismo/diagnóstico , Síndromes de Imunodeficiência/diagnóstico , Ataque Isquêmico Transitório/diagnóstico , Osteocondrodisplasias/diagnóstico , Encéfalo/patologia , Criança , Nanismo/genética , Nanismo/imunologia , Humanos , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/imunologia , Ataque Isquêmico Transitório/genética , Ataque Isquêmico Transitório/imunologia , Imageamento por Ressonância Magnética , Masculino , Osteocondrodisplasias/genética , Osteocondrodisplasias/imunologia , Síndrome
13.
Eur J Pediatr ; 147(1): 41-6, 1988 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-3422189

RESUMO

Several PVC medical devices contain the plasticizer Di-(2-ethylhexyl)-phthalate (DEHP) in high concentration. Taken systematically DEHP only has minor toxic effects in the human organism. In three preterm infants artificially ventilated with PVC respiratory tubes unusual lung disorders resembling those observed in hyaline membrane disease, verified both clinically and radiologically, were observed during the fourth week of life. It was assumed that these lung disorders were causally related to the exposure to high doses of DEHP, which was released from the walls of the respiratory tubes. DEHP was found in the lung tissue of one patient who died of pneumothorax soon after birth after being artificially ventilated. It is strongly recommended that for disposable PVC respiratory devices the plasticizer DEHP should be used with more restrictions.


Assuntos
Dietilexilftalato/efeitos adversos , Ácidos Ftálicos/efeitos adversos , Síndrome do Desconforto Respiratório do Recém-Nascido/terapia , Ventiladores Mecânicos/efeitos adversos , Dietilexilftalato/análise , Segurança de Equipamentos , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Recém-Nascido , Pulmão/análise , Masculino
14.
Clin Exp Hypertens A ; 8(4-5): 871-7, 1986.
Artigo em Inglês | MEDLINE | ID: mdl-3530561

RESUMO

Nifedipine given by the sublingual route has been used in the treatment of 30 hypertensive emergencies in 20 children suffering from renal disease. The mean dosage of nifedipine was 0.33 mg/kg body weight. In 20 hypertensive crises occurring in 16 patients a single dose of nifedipine was sufficient to lower systolic as well as diastolic blood pressure significantly within 90 min. for a period of 4 to 12 hours. No side effects were noted with the exception of a transient flush in one patient. Nifedipine proved to be suitable for the primary treatment of hypertensive emergencies in children suffering from renal hypertension. The advantages of nifedipine compared to other drugs used for treating hypertensive crises is the rapid onset of the antihypertensive action without need for an intravenous form of administration.


Assuntos
Hipertensão Renal/tratamento farmacológico , Nifedipino/uso terapêutico , Adolescente , Pressão Sanguínea/efeitos dos fármacos , Criança , Pré-Escolar , Ensaios Clínicos como Assunto , Emergências , Humanos , Hipertensão Renal/fisiopatologia , Lactente , Soalho Bucal , Nifedipino/administração & dosagem
15.
Blut ; 49(6): 427-39, 1984 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-6509215

RESUMO

A previously described mathematical model of the hematopoietic stem cell system has been extended to permit a detailed understanding of the data during and after hypoxia. The model includes stem cells, erythroid and granuloid progenitors and precursors. Concerning the intramedullary feedback mechanisms two basic assumptions are made: 1) The fraction "a" of CFU-S in active cell cycle is regulated. Reduced cell densities of CFU-S, progenitors or precursors lead to an accelerated stem cell cycling. Enlarged cell densities suppress cycling. 2) The self renewal probability "p" of CFU-S is also regulated. The normal steady state is described by p = 0.5, indicating that on statistical average each dividing mother stem cell is replaced by one daughter stem cell, while the second differentiates. Diminished cell densities of CFU-S or enlarged densities of progenitors and precursors induce a more intensive self renewal (p greater than 0.5), such that the stem cell number increases. The self renewal probability declines (p less than 0.5) if too many CFU-S or too few progenitors and precursors are present. The model reproduces bone marrow data for CFU-S, BFU-E, CFU-C, CFU-E, 59 Fe-uptake and nucleated cells in hypoxia and posthypoxia. Although the ratio of differentiation into the erythroid and granuloid cell lines is kept constant in the model, a changing ratio of CFU-E and CFU-C results. The model suggests that stem cells and progenitor cells are regulated by a regulatory interference of erythropoiesis and granulopoiesis.


Assuntos
Células-Tronco Hematopoéticas/fisiologia , Hipóxia/sangue , Diferenciação Celular , Eritropoese , Hematopoese , Humanos , Cinética , Modelos Biológicos , Timidina/metabolismo
16.
Klin Wochenschr ; 61(19): 935-40, 1983 Oct 03.
Artigo em Alemão | MEDLINE | ID: mdl-6358650

RESUMO

The use of mathematical models in haematology is shown by some examples concerning stem cell kinetics, erythropoiesis and thrombopoiesis. At first, model assumptions are formulated which include the biological knowledge and some regulatory hypotheses. Then, the reaction of the model on stimulation and suppression is calculated. Finally, by comparison with experimental or clinical data one can evaluate how far the model assumptions are sufficient to understand the measurements. Thus one can exclude wrong hypotheses and identify the important regulatory influences.


Assuntos
Hematologia , Modelos Biológicos , Plaquetas/fisiologia , Eritropoese , Granulócitos/fisiologia , Hematopoese , Células-Tronco Hematopoéticas/fisiologia , Humanos
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