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Biomedical subjects

G B Schaefer

Publications and source records attributed to G B Schaefer.

At least 37 records · Page 2Linked to original sources
PubMed1997

The neuroimaging findings in Sotos syndrome.

We reviewed the neuroimaging studies of 40 patients with classic Sotos syndrome. The studies consisted of CT scans only in 4 patients and one or more MRI scans in 36 patients. The diagnosis of Sotos syndrome was made using well-established clinical criteria. The neuroimaging studies of each patient were evaluated subjectively by visual inspection and the chief findings were tabulated and grouped into five categories: 1) ventricular abnormalities, 2) extracerebral fluid spaces, 3) midline abnormalities, 4) migrational abnormalities, and 5) others. The most common abnormality of the cerebral ventricles was prominence of the trigone (90%), followed by prominence of the occipital horns (75%) and ventriculomegaly (63%). The supratentorial extracerebral fluid spaces were increased for age in 70% of the patients and the fluid spaces in the posterior fossa were increased in 70% also. A variety of midline abnormalities were noted but anomalies of the corpus callosum were almost universal. Gray matter heterotopias occurred in only 3 (8%) of 36 patients. Periventricular leukomalacia, presumably the result of prenatal or perinatal difficulties and unrelated to the basic condition, was the most common of the miscellaneous other abnormalities noted. The neuroimaging findings of Sotos syndrome are distinct enough to allow differentiation of this syndrome from other mental retardation syndromes with macrocephaly.

Abnormalities, Multiple↗
PubMed1997

Marshall-Stickler phenotype associated with von Willebrand disease.

We report on 6 individuals from three different kindreds with Marshall-Stickler (MS) phenotype, with characteristic orofacial abnormalities, arthropathy, deafness, and eye findings, all of whom were discovered to have a mild bleeding diathesis and coagulation-study findings consistent with mild von Willebrand disease (vWD). MS syndrome has been linked in some cases to the type II procollagen gene (COL2A1) on chromosome 12q, and to the collagen XI gene (COL11A2) on chromosome 6. The von Willebrand factor (vWF) is encoded by a 180-Kb gene located on the short arm of chromosome 12. This is the first reported association of these two disorders.

Adolescent↗
PubMed1997

Regulation of MMP-9 (92 kDa type IV collagenase/gelatinase B) expression in stromal cells of human giant cell tumor of bone.

Matrix metalloproteinases (MMPs) play an important regulatory role in tissue morphogenesis, cell differentiation, tumor invasion and metastasis. Several authors have reported a direct correlation between the production of 72 kDa (MMP-2) and 92 kDa (MMP-9) type IV collagenases/gelatinases and the metastatic potential of cancer cells. Recently, we have identified the expression of both MMP-2 and MMP-9 in primary cultures of human giant cell tumor (GCT) of bone in vitro, and in tissue extracts in vivo. Interestingly, MMP-9 is not secreted by late-passaged GCT cells. It is possible that the production of MMP-9 is regulated by certain factor(s) secreted by the multinucleated giant cells in the primary culture. In order to test this hypothesis, the effect of primary-culture-conditioned medium on the expression of MMP-9 by late-passaged mononuclear stromal cells was examined. Adding conditioned medium from the primary GCT culture to the late-passaged stromal cells induced MMP-9, as evidenced by the presence of lytic bands at M(r) 92,000 and 72,000 on a gelatin zymogram. These enzyme activities were inhibited by EDTA, a well-known inhibitor of the MMPs. We confirmed these results by Western blotting using specific antibodies and RT-PCR for MMP-2 and MMP-9. Immunofluorescence studies with specific antibodies to MMP-9 further confirmed its expression by the passaged stromal cells cultured in the primary-culture-conditioned medium. The data indicate that MMP-2 and MMP-9 are produced by the mononuclear stromal cells when cultured in GCT primary-culture-conditioned medium. This suggests that multinucleated giant cells in primary cultures secrete a factor(s) that stimulates stromal cells to produce MMP-9, which, in turn, may contribute to the aggressive behavior of GCT.

Adolescent↗
PubMed1997

Clinical variability of tetrasomy 12p.

We describe five patients with tetrasomy 12p (one previously reported). These patients exhibit a very wide range of phenotypic features from that of classic Pallister-Killian syndrome to only mild learning disabilities with pigmentary skin changes. As such, these cases highlight the fact that tetrasomy 12p [i(12p)] and Pallister-Killian syndrome are not synonymous, although this combination of genotype and phenotype is often seen. This information is especially important in prenatally ascertained i(12p). The full spectrum of phenotypic possibilities associated with this chromosome aneuploidy should be discussed in prenatal counseling.

Abnormalities, Multiple↗
PubMed1997

Macrocerebellum: neuroimaging and clinical features of a newly recognized condition.

Other than hamartomatous enlargement of the cerebellum as in Lhermitte-Duclos syndrome, diffuse enlargement of the cerebellum is not clearly described. We report four patients (ages 9 months to 2 years) with diffusely enlarged cerebelli as identified by measurement of the cerebellum and comparison to age appropriate normal values. The cerebellar measurements were determined in absolute numbers and expressed as ratios of cerebellum to whole brain and supratentorial brain. The clinical features of these four children (3 boys, 1 girl) consistently include global developmental delay, tone abnormalities, preserved reflexes, delayed or abnormal maturation of the visual system (oculomotor apraxia), and deficient or delayed myelination of cerebral white matter. The etiology of the macrocerebellum is unknown but we propose that the cerebellum is responding to the elaboration of growth factors intended to augment the slow development of cerebral structures. Regardless of the etiology, the finding of a macrocerebellum appears to allow the clinician to predict the clinical features of the patient and probably represents a marker for disturbed cerebral development.

Brain↗
PubMed1997

Dementia pugilistica and cavum septi pellucidi: born to box?

Described nearly 70 years ago as the 'punch drunk' syndrome, dementia pugilistica has recently received increasing attention in both the medical and lay press. The association between the finding of cavum septi pellucidi and dementia in old boxers was first described by Ferguson and Mawdsley in 1965. Since then it has commonly been listed as one of the features of this condition. We review the significance and the epidemiology of cavum septi pellucidi and present an alternative explantation for the association between this developmental anomaly of the brain and dementia pugilistica.

Aged↗
PubMed1997

Robin sequence.

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Humans↗
PubMed1997

Stickler syndrome.

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Chromosome Aberrations↗
PubMed1996

Hypoplasia of the cerebellar vermis in neurogenetic syndromes.

There are conflicting reports on the relationship between cerebellar vermal lobule hypoplasia and autism. Using quantitative magnetic resonance image analysis, we measured the cerebellar vermis in 125 normal individuals with a broad age range and 102 patients with a variety of neurogenetic abnormalities. We conclude that hypoplasia of cerebellar vermal lobules VI and VII is a nonspecific finding that even occurs in several conditions with-out autistic behavior. This suggests that it is not a specific neuroanantomical marker for autism, nor is cerebellar dysgenesis likely to be solely responsible for clinical autistic behaviors.

Abnormalities, Multiple↗
PubMed1996

Size of the corpus callosum in cerebral palsy.

It has been suggested that the size of the corpus callosum may have diagnostic significance in cerebral palsy, although this relationship is incompletely defined. Ninety-one patients with cerebral palsy had been studied by magnetic resonance imaging in the 5-year period from 1990 to 1994. Fifty-seven of these 91 patients had a technically appropriate midsagittal magnetic resonance image for quantitative morphometric analysis. The ratio of the area of the corpus callosum to the area of the supratentorial brain was compared to published age- and gender-specific norms. Imaging findings were correlated with clinical history and cause of cerebral palsy. The corpus callosum was of normal size in 43 patients and more than 2 standard deviations below the mean in 14 patients. The causes for cerebral palsy included hypoxic ischemic encephalopathy (32), cerebral dysgenesis (8), and porencephalic strokes (6); the etiology could not be established in 11 patients. The size of the corpus callosum was highly correlated with the cause of cerebral palsy, such that all patients with cerebral dysgenesis had hypoplasia of the corpus callosum (one-sided z test, p < 0.0001). Conversely, the callosum was of normal size in 32 of 38 patients with hypoxic ischemic encephalopathy and porencephalic strokes. The presence of a hypoplastic corpus callosum is highly associated with cerebral dysgenesis as a cause for cerebral palsy.

Adolescent↗
PubMed1995

Familial inverted duplication 7p.

A 10-month-old female with developmental delay and failure to thrive was referred for genetic evaluation as part of an adoption assessment. Physical exam showed a mildly beaked nose and clinodactyly, but otherwise nothing remarkable. Chromosome analysis showed an inverted duplication of the p12.2-->p13 portion of chromosome 7[(46,XX, dup(7)(p13p12.2)]. The proposita's older brother, mother, and grandmother were cognitively delayed and had the same chromosome 7 duplication. A review of the literature showed no other cases involving this exact duplication.

Chromosome Inversion↗
PubMed1995

Expression of 72 kDa and 92 kDa type IV collagenases from human giant-cell tumor of bone.

Basement membrane forms widespread barriers to tumor invasion. It has been shown that tumor-secreted, basement membrane-degrading enzymes, namely metalloproteinases (MMPs) play an important role in tumor invasion and metastasis. In this study, we determined the enzymatic activity, content, and mRNA of both the 72 kDa (MMP-2) and 92 kDa (MMP-9) MMPs in primary cultures of human giant-cell tumor of bone (GCT) in vitro and in tissue extracts (in vivo). Gelatin zymography showed the presence of lytic bands at M(r) 121,000, 92,000, and 72,000, and these enzymatic activities were inhibited by EDTA, an inhibitor of MMPs. Western blots with antibodies specific for MMP-2 and MMP-9 confirmed the presence of MMP-2 and MMP-9 both in vitro and in vivo, but GCT cells at late passage showed only MMP-2. Northern blots using labeled cDNA probes specific for these molecules revealed the presence of 3.1 kb transcript for MMP-2 and a 2.9 kb transcript for MMP-9. Using specific antibodies to 72 kDa and 92 kDa type IV collagenases, we studied their cellular distribution by immunohistochemical means. Stronger immunoreactivity was found for 92 kDa type IV collagenase than 72 kDa type IV collagenase in the giant cells. It appears, therefore, that MMP-9 may play an important role in the malignant behavior of GCTs and suggests a potential therapeutic role for protease inhibitors in attempting to minimize the invasive behavior of GCTs.

Bone Neoplasms↗
PubMed1995

Quantitation of fibrillin immunofluorescence in fibroblast cultures in the Marfan syndrome.

The Marfan syndrome (MFS) is a heritable connective tissue disorder manifested by defects in the skeletal, ocular, and cardiovascular systems. Diagnosis of MFS is based on clinical findings. At present there are no laboratory tests for specific determination of this disorder. Defects in fibrillin, an elastin-associated microfibrillar glycoprotein, are now known to cause the variable and pleiotropic manifestations of MFS. Immunofluorescence studies of skin sections and dermal fibroblast cultures were the first to show this association. Most unequivocal cases of the Marfan syndrome exhibited an apparent reduction in fibrillin immunofluorescence. The prospect of examining patients whose clinical findings suggest a possible diagnosis of the Marfan syndrome has stimulated us to attempt quantitation of immunofluorescence. In the study described here we used computer-enhanced image analysis to establish "normal" and "abnormal" (Marfan) parameters of fibrillin immunofluorescence in dermal fibroblast cultures. Quantitation of fluorescence from control individuals showed a median of 21%, while the median fibrillin fluorescence in MFS patients was 6% with a confidence interval of < or = 15%. These findings were statistically significant to p < 0.01. It is hoped that these analyses may become a useful adjunct in the clinical diagnosis of MFS.

Cells, Cultured↗