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Biomedical subjects

A Klar

Publications and source records attributed to A Klar.

At least 37 records · Page 2Linked to original sources
PubMed1996

Focal bacterial nephritis (lobar nephronia) in children.

We report 13 patients with 16 episodes of acute lobar nephronia diagnosed in a prospective study that was conducted among 210 hospitalized children with urinary tract infection. In 30 episodes of urinary tract infection, a hypoechogenic or hyperechogenic lesion was found. Twenty patients underwent computed tomography, and in 16 of them acute lobar nephronia was diagnosed. Evolution to renal abscess occurred in 25%. Prolonged intravenous antibiotic treatment was sufficient in all cases.

Abscess↗
PubMed1995

Lipomatosis of the scalp and macrocephaly.

In summary, a case of macrocephaly and lipomatosis of the scalp and forehead has been presented. The phenotypic and clinical features found in our patient are in accordance with previous reports. The differential diagnosis with other hamartoneoplastic syndromes has been evaluated and discarded, concluding that the present report is in accordance with Bannayan-Zonana syndrome. However, as in other inherited traits, finding a genetic test to diagnose this entity remains a challenge.

Child, Preschool↗
PubMed1993

Ectopic neural expression of a floor plate marker in frog embryos injected with the midline transcription factor Pintallavis.

The floor plate, a cell group that develops at the midline of the neural plate in response to inductive signals from the notochord, has been implicated in the control of dorsoventral neural pattern. The frog Pintallavis gene, encoding a member of the HNF-3/fork head transcription factor family, is expressed in the notochord and in midline neural plate cells that give rise to the floor plate. To examine whether Pintallavis might be involved in regulating the differentiation of the floor plate, we ectopically expressed Pintallavis by injection of synthetic mRNA into two-cell frog embryos. Injection of Pintallavis mRNA resulted in the ectopic expression of F-spondin, a gene encoding a floor plate-specific adhesion molecule, at the dorsal midline of the neural tube. The expression of Pintallavis in midline cells may therefore contribute to the establishment of the floor plate fate.

Albinism↗
PubMed1993

A kindred with Griscelli disease: spectrum of neurological involvement.

We report four members of a highly consanguineous family with silver-grey pigmentation of hair, two of whom had skin histology compatible with Griscelli disease. Unlike previously reported patients, they did not suffer from recurrent infections. In addition, there was a spectrum of neurological involvement varying from mild cognitive delay with a convulsive disorder in one patient, to a fatal degenerative course in three others. One patient developed a prolonged febrile illness with histological evidence of florid lymphoid hyperplasia.

Child, Preschool↗
PubMed1993

Deteriorating neurological and neuroradiological course in treated biotinidase deficiency.

We report a 7-month-old female baby with recent onset of neurological manifestations and mucocutaneous candidiasis. Immunological findings were compatible with severe combined immune deficiency (SCID). Infectious etiology of the central nervous system (CNS) involvement was ruled out. Biotinidase deficiency was suspected because of the concomitance of neurological and immunological deficits and was confirmed by enzymatic assay. Comprehensive treatment, including bone marrow transplantation (BMT) and biotin, resulted in immunological recovery, but no improvement of neurological condition. Serial brain CT scans over a period of 2 1/2 years demonstrated profound progression of brain atrophy involving gray matter.

Amidohydrolases↗
PubMed1993

Extinction of Oct-3/4 gene expression in embryonal carcinoma x fibroblast somatic cell hybrids is accompanied by changes in the methylation status, chromatin structure, and transcriptional activity of the Oct-3/4 upstream region.

In this study we evaluate, for the first time, the molecular mechanism that underlies the extinction of a tissue-specific transcription factor, Oct-3/4, in somatic cell hybrids and compared it with its down-regulation in retinoic acid (RA)-treated embryonal carcinoma (EC) cells. The Oct-3/4 gene, which belongs to the POU family of transcription factors and is abundantly expressed in EC (OTF9-63) cells, provides an excellent model system with which to study the extinction phenomenon. Unlike other genes whose expression has been repressed in hybrid cells but not during in vivo differentiation, Oct-3/4 expression is dramatically repressed in OTF9-63 x fibroblast hybrids and also during embryogenesis. The ectopic expression of Oct-3/4 in hybrid cells under a constitutive promoter is sufficient for transcriptional activation of an octamer-dependent promoter. These results argue against the possibility that fibroblasts contain a direct repressor which binds directly to the octamer sequence and prevents Oct-3/4 protein from binding. The extinction of Oct-3/4 binding activity in the hybrid cells occurs at the level of mRNA transcription, similarly to the repression of Oct-3/4 transcription during in vivo differentiation. This shutdown of Oct-3/4 transcription in hybrid cells and in RA-treated EC cells is accompanied by de novo methylation of its 1.3-kb upstream region. In contrast to EC cells, in which this region is sensitive to MspI digestion, in hybrid cells and in RA-treated EC cells, the Oct-3/4 upstream region is resistant to MspI digestion, which suggests a change in its chromatin structure. Furthermore, extinction is not restricted to the endogenous Oct-3/4 gene but is also exerted upon a transiently transfected reporter gene driven by the Oct-3/4 upstream region. Thus, changes in the cellular activity of trans-acting factors acting on the upstream region also contribute to the inability of the hybrid and RA-treated EC cells to generate Oct-3/4 transcripts. In conclusion, this study draws a connection between the shutdown of Oct-3/4 expression in RA-differentiated EC cells and its extinction in hybrid cells. In both systems, repression of Oct-3/4 expression is achieved through changes in the methylation status, chromatin structure, and transcriptional activity of the Oct-3/4 upstream regulatory region.

Animals↗
PubMed1992

F-spondin: a gene expressed at high levels in the floor plate encodes a secreted protein that promotes neural cell adhesion and neurite extension.

The floor plate is a cell group implicated in the control of neural cell pattern and axonal growth in the developing vertebrate nervous system. To identify molecules that might mediate the functions of the floor plate, we have used subtractive hybridization techniques to isolate floor plate-enriched cDNA clones. One such clone encodes a novel secreted protein, F-spondin, which is expressed at high levels in the floor plate. The C-terminal half of the protein contains six repeats identified previously in thrombospondin and other proteins implicated in cell adhesion. F-spondin is expressed in the floor plate at the time that axons first extend and at lower levels in the peripheral nerve. Recombinant F-spondin promotes the attachment of spinal cord and sensory neuron cells and the outgrowth of neurites in vitro. F-spondin may contribute to the growth and guidance of axons in both the spinal cord and the PNS.

Amino Acid Sequence↗
PubMed1992

Eicosanoids content in small intestinal mucosa of children with celiac disease.

Celiac disease (CD) is characterized by diarrhea, growth retardation, and weight loss in genetically susceptible subjects on a gluten-containing diet. The exact pathogenesis of CD is still obscure, but it is considered to be immunologically mediated. We have previously shown elevated prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) content in small intestinal mucosa obtained from active celiac children. In the present study, we found significantly elevated PGE2, leukotriene B4 (LTB4), and leukotrienes C4, D4, and E4 (LTC4D4E4) content in small bowel mucosa from children suffering from CD on a gluten-containing diet in comparison to control subjects. PGE2 was 25,278 +/- 7,761 vs. 4,478 +/- 426 pg/mg of protein (mean +/- SEM), respectively. LTB4 was 8,807 +/- 3,706 vs. 403 +/- 63 pg/mg of protein (mean +/- SEM), respectively. LTC4D4E4 was 15,369 +/- 4,085 vs. 2,998 +/- 279 pg/mg of protein (mean +/- SEM), respectively. We conclude that the elevated content of arachidonic acid metabolic products via cyclooxygenase and lipoxygenase pathways may contribute to the diarrhea and may be involved in the pathogenesis of mucosal injury.

Adolescent↗
PubMed1991

Barrett's esophagus in a young patient with Raynaud's phenomenon.

We describe a 12-year-old girl with Raynaud's phenomenon (RP) of 3 years' duration, who developed Barrett's esophagus with severe stricture. Barrett's esophagus complicating progressive systemic sclerosis has been reported in adult patients, but not in childhood. Barrett's esophagus following RP alone has not been reported, to the best of our knowledge, in any age group.

Barrett Esophagus↗
PubMed1990

Acute pyelonephritis due to a Kluyvera species in a child.

A Kluyvera sp. was recovered from the urine of a previously healthy 5-year-old child with clinical and laboratory evidence of acute pyelonephritis. This pathogen is usually a saprophyte and even when recovered in humans it is ordinarily considered an opportunistic pathogen. Only two other cases of Kluyvera infection have been described in immunocompetent individuals. The case presented further supports the finding that this bacterium can cause severe disease even in previously healthy, immunocompetent children.

Acute Disease↗
PubMed1990

Disappearance of IgM antibodies to hepatitis A virus after an acute infection in children and adolescents.

The kinetics of IgM antibodies to hepatitis A virus (HAV) following an acute infection, were studied in 17 children. Antibodies disappeared in two patterns, one group at 113 +/- 18 days after the acute infection in the children, and the second group at 283 +/- 90 days. The same two patterns of kinetics were seen in adults. We conclude that IgM anti-HAV antibodies can be found in the sera of children for over 6 months after the acute infection, as was observed in adults.

Acute Disease↗
PubMed1990

The Niikawa-Kuroki (Kabuki make-up) syndrome in a Moslem Arab child.

The Niikawa-Kuroki "Kabuki Make-Up" syndrome is a rare sporadic malformation syndrome, characterised by severe psychomotor and growth retardation, peculiar facies, including long palpabral fissures and large malformed ears and skeletal abnormalities. We report a 2-year-old Moslem Arab boy with 28 of the 32 originally described features of this syndrome and in addition with hyperelastic joints, hypospadias and scaphocephaly which were not previously described in association with the Kabuki make-up syndrome. This is the fifth reported case of this syndrome in a non-Japanese patient, and the second reported case in a patient of Arab descent.

Abnormalities, Multiple↗