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G H Jansen

Publications and source records attributed to G H Jansen.

At least 73 records · Page 4Linked to original sources
PubMed1996

Expression pattern of the von Hippel-Lindau protein in human tissues.

von Hippel-Lindau (VHL) disease is an autosomal dominant inherited disorder characterized by extensively vascularized tumors and cysts in specific organs. The VHL gene product plays a critical role in the regulation of transcription elongation by RNA polymerase II. To provide insight into which cells the VHL protein is expressed, we performed immunohistochemistry on human tissue and tumors. The VHL protein was widely expressed in normal human tissue. The cellular distribution of the protein was confined to the cytoplasm of specific cell types. High levels of expression of the protein were observed in neural tissue, especially in Purkinje cells, Golgi type II cells, and dentate nucleus of the cerebellum, pontine nuclei, the inferior olivary nucleus of the medulla oblongata, orthosympathetic ganglia, myenteric, and submucous plexus of the colon. In the other target organs of the VHL disease, high expression was observed in the renal tubule system, the exocrine pancreas, the adrenal cortex, and liver parenchyma. The VHL protein was also expressed in organs not at risk for the disease. The eosinophilic cells of the pituitary gland, epithelial cells of the follicles of the thyroid, epithelial cells of the intestines, bile ducts, and bronchial epithelia showed strong VHL immunoreactivity. Immunohistochemistry did not facilitate the discrimination of tumors obtained from VHL patients or tumors unrelated to the VHL disease. Renal cell carcinomas, hemangioblastomas, and pheochromocytomas, either VHL-related or sporadic, demonstrated positive staining for the VHL protein, which suggests that the antibody also recognizes the mutated VHL protein. The present study suggests a role for the VHL gene that goes beyond the organs involved in the disease. The recognition of cell-specific VHL expression provides a framework for further studies to elucidate the normal function of the VHL gene and to determine its role in specific cell types.

Carcinoma, Renal Cell↗
PubMed1995

Treatment of combined hyperlipidemia with fluvastatin and gemfibrozil, alone or in combination, does not induce muscle damage.

Although combination therapy using 3-hydroxy-3-methylglutaryl coenzyme A (HMG-Co-A) reductase inhibitors and fibrates is efficacious in combined hyperlipidemia, such treatment has been associated with myopathy. For this reason, we studied the effects of fluvastatin and gemfibrozil, alone or in combination, on muscle. A total of 21 patients with combined hyperlipidemia were recruited who were matched for age, body mass index, and baseline levels of total cholesterol, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), triglycerides, creatine phosphokinase, and myoglobin. Patients were randomized to three groups for 6-week treatment with fluvastatin at 40 mg/day, gemfibrozil at 600 mg twice daily, or a combination of the two drugs. Parameters for muscle damage were rises in levels of serum creatine phosphokinase and myoglobin compared with pre-exercise levels; these were assessed 1 hr and 8 hr after a 45 min lean body mass standardized ergometer test, which was performed before and after treatment in all patients. Biopsies from the quadriceps muscle were taken 48 hr after each test. Fluvastatin lowered total cholesterol and LDL-C by 23% and 35%, respectively (p < 0.01), with no effects on triglycerides and HDL-C. Gemfibrozil lowered triglycerides by 40% (p < 0.01) but did not lower total cholesterol or LDL-C significantly. The combination therapy decreased total cholesterol, LDL-C, and triglycerides by 28%, 29%, and 39%, respectively (p < 0.05). Pre-exercise creatine phosphokinase and myoglobin levels were not affected by treatment in any group.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticholesteremic Agents↗
PubMed1994

Intracranial lesions in the fullterm infant with hypoxic ischaemic encephalopathy: ultrasound and autopsy correlation.

To test the hypothesis that cranial ultrasound correlated with post-mortem findings in neonates with hypoxic ischaemic encephalopathy (HIE), the brains of 20 infants who died after at least two real time ultrasound scans were examined. The ultrasound abnormalities detected in the periventricular/subcortical white matter, cortex or thalami were compared with the macroscopic and histological appearances. Comparing the last ultrasound scan which was performed no longer than 12 hours before the infant died, with histological data, the sensitivity and specificity for lesions in the thalamus was 100% and 83.3% respectively; for cortical lesions 76.9 and 100% respectively and for lesions in the periventricular white matter 80% and 75% respectively. The value of cranial ultrasound for detecting intracranial abnormalities in infants with HIE was considerably better than reported previously. This could mainly be attributed to the use of a 10 MHz transducer which was of critical importance to identify lesions in the superficial cortical layer.

Basal Ganglia↗
PubMed1994

Unilateral haemorrhagic parenchymal lesions in the preterm infant: shape, site and prognosis.

In a prospective cranial ultrasound study of 544 infants with a gestational age of 32 weeks or less, 20 (3.6%) infants were diagnosed as having a unilateral parenchymal lesion (PL). Based on the shape of the PL and the evolution on ultrasound, the infants were divided into three groups: group I consisted of 11 infants, in whom the PL was triangular/fan-shaped and separate from the ventricle. The PL evolved into small cystic lesions; group II comprised 3 infants who had a PL with a similar shape, but partially communicating with the ventricle; group III consisted of 6 infants who had a globular-shaped lesion in communication with the ventricle. In groups II and III, the PL evolved into one porencephalic cyst. The PL was considered to be due to venous infarction in all cases with intraventricular haemorrhage preceding the PL in 7 cases. Sixteen infants survived. A postmortem was performed in 2 of the 4 infants who died, confirming the diagnosis of venous infarction. Neurological sequelae were present in only 2 cases in the first group, while all 6 survivors of the other two groups developed mild to severe hemiplegia. Long-term follow-up was not always available and 4 of the 18 survivors were still less than 18 months when last seen. In 9 of the 11 infants in group I, the PL was localized in the frontoparietal region, while in 8 of the 9 infants in group II or III, the PL was beyond the trigone in the occipital region. The outcome of the unilateral PL is not always unfavourable.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗
PubMed1994

Cerebral lactate and N-acetyl-aspartate/choline ratios in asphyxiated full-term neonates demonstrated in vivo using proton magnetic resonance spectroscopy.

The purpose of this study was to test the hypothesis that a high lactate signal and a low N-acetyl-aspartate/choline ratio in neonates with postasphyxial encephalopathy indicated a high chance of an adverse outcome in vivo when proton magnetic resonance spectroscopy was used. Twenty-one full-term asphyxiated neonates were examined at a mean postnatal age of 7.1 d. Five patients died, and five survivors had handicaps. Eleven of the 16 survivors (seven without handicaps and four with handicaps) had a second examination at 3 mo of age. After magnetic resonance imaging, spectra were obtained at 1.5 tesla. A 20-mm-thick slice was selected through the basal ganglia. After optimizing the B-0 field, we used a double spin-echo pulse sequence (90-180-180 degrees) with a time to repeat of 2000 ms and a time to echo of 272 ms. Two-dimensional spectroscopic imaging was performed by 32 x 32 phase encoding steps in two directions in a 225-mm field of view, resulting in 1-mL volumes, followed by computerized processing. Neuromotor development was examined at 6 wk, 3 mo, and every 3 mo thereafter. Lactate resonances were seen only in the five patients with grade 3 postasphyxial encephalopathy. Lactate was distributed diffusely (n = 4), or localized in areas of infarction (n = 1). N-acetyl-aspartate/choline ratios were significantly lower in the patients with an adverse outcome than in the survivors without handicaps, both neonatally (p < 0.005, Wilcoxon's rank sum test) and at 3 mo (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aspartic Acid↗
PubMed1994

Temporal lobe epilepsy: the various MR appearances of histologically proven mesial temporal sclerosis.

PURPOSE: To determine the frequency of appearance of various MR signs in mesial temporal sclerosis, to determine the optimal scanning planes for their visualization, and to propose a histologic explanation for the diminished demarcation between gray and white matter in the temporal lobe, a frequent MR finding in patients with mesial temporal sclerosis. METHODS: MR scans of 14 surgically treated patients with epilepsy and histologically proven mesial temporal sclerosis were assessed for the presence of six features: feature 1, high signal intensity in the hippocampus; 2, reduced hippocampal size; 3, ipsilateral atrophy of the hippocampal collateral white matter; 4, enlarged temporal horn; 5, reduced gray-white matter demarcation in the temporal lobe; and 6, decreased temporal lobe size. RESULTS: Feature 1 was present in 14 patients and was best appreciated on the T2-weighted images in planes parallel to the long axes of the hippocampi. Feature 2, present in 12 patients, and feature 6, present in 9 patients, were optimally seen in the coronal planes and on the inversion-recovery sequences in particular. Feature 3, present in 12 patients, was optimally seen on the coronal T2-weighted images. Feature 4, seen in 11 patients, was equally well seen in all planes (transverse, coronal, and parallel to the long axes of the hippocampi). Feature 5, seen in 10 patients, was best appreciated on the T2-weighted images in the planes of the long axes of the hippocampi. Histologic investigation of the temporal lobe white matter in the 10 patients with feature 5 demonstrated on the MR scan showed abnormalities in 7 cases. Oligodendroglia cell clusters were found in 6, with concomitant corpora amylacea in 1 case and perivascular macrophages with pigment a sole finding in another case. CONCLUSION: Of the six features found in cases of mesial temporal sclerosis on MR, increased hippocampal signal intensity is the most consistent. A decreased gray-white matter demarcation in the temporal lobe parenchyma is also a frequent feature of this disease. A combination of multiple scanning planes results in an optimal demonstration of lesions.

Adolescent↗
PubMed1993

Mycotic encephalitis: predilection for grey matter.

In mycotic infections of the brain three patterns of abnormality may be observed: meningitis, granuloma, and encephalitis. The first two, consisting of diffuse meningeal enhancement and mass lesion respectively, can easily be visualised by CT or MRI, but are nonspecific. The third pattern has been described histopathologically; as the clinical picture is nonspecific and the diagnosis is often unsuspected, especially in immunocompetent patients, acquaintance with the characteristic CT and MRI patterns of mycotic encephalitis may help in establishing the correct diagnosis, with important therapeutic consequences.

Adult↗
PubMed1993

Growth of cultured human glioma tumour cells can be regulated with histamine and histamine antagonists.

The 50% survival time for low grade astrocytomas is 50 months and for high grade astrocytomas it is 13 months, underlining the need for new therapies. Several reports show that in vivo histamine antagonists cause retardation of tumour growth in some animal models and prolonged survival in cancer patients. Therefore we have tested the growth modulating effects of histamine and histamine antagonists on human glioma cultures. Twelve freshly excised human gliomas were cultured and tested for their in vitro sensitivity to histamine and histamine antagonists. Four continuous glioma cell lines were used to confirm the glioma-specificity of the effects observed in the primary cell lines. In low serum concentration (0 or 1%) the growth of 5/9 primary glioma-derived cultures could be stimulated with 0.2 mM histamine, and in 4/5 cases with 0.2 microM histamine. One mM of the histamine H2-receptor antagonist cimetidine could inhibit the growth of 4/5 primary glioma cultures when tested in 1% human AB serum, and of 6/13 cases when tested in 1% FCS. Lower concentrations (down to 1 microM) were less effective. The histamine H1-receptor antagonist pyrilamine gave variable results. The specificity of the effects is indicated by the absence of a generalised toxic effect, by the observation that the antagonist-induced inhibition could be reversed with histamine, and by the correlation of the obtained cimetidine-induced growth inhibition with the maximal growth rate of the primary cell lines in 10% FCS. The observed cimetidine-induced inhibition of the in vitro proliferation of gliomas suggests that cimetidine is a relevant candidate for the in vivo growth inhibition of these tumours.

Adult↗
PubMed1992

The neural and neuro-endocrine component of the human thymus. I. Nerve-like structures.

The presence of nerve-like fibers in the human thymus was studied by immunohistochemistry on frozen tissue sections and sections of formalin-fixed paraffin-embedded tissue, for neurofilaments (Nf) of 68-, 160-, and 200-kDa (neuron-specific structural proteins), neuron-specific protein PGP9.5, tyrosin hydroxylase (noradrenergic innervation), chromogranin A (CHROM), synaptophysin (SYN), and the pituitary hormones follicle-stimulating hormone (FSH) and its beta-subunit, growth hormone, adrenocorticotropic hormone, luteinizing hormone, prolactin, beta-subunit of thyroid-stimulating hormone, and somatostatin. Noradrenergic profile-like immunoreactivity was observed in the medulla: immunolabeling was observed also for epithelial cells surrounding Hassall's corpuscles. For neurofilaments, only Nf 160-kDa immunoreactivity was observed in the thymic parenchyma, mainly in long-sized labeling patterns in the medulla. PGP9.5 immunolabeling occurred especially in the cortex, in dendritic labeling patterns compatible with the epithelial network at this location. The medulla showed PGP9.5 immunoreactivity in fiber-like patterns and in large-sized epithelial cells surrounding Hassall's corpuscles. Immunoreactive CHROM was seen in profile-like structures in the subcapsule, cortex, and medulla. SYN immunolabeling occurred focally around Hassall's corpuscles. Profile-like structures immunoreactive for pituitary hormones were observed in the medulla and in less density in the cortex. For FSH the highest density occurred in the cortex, where long-sized profile-like structures were present running over and in between cells, especially in the keratin-positive epithelial dendritic network (two-color immunohistochemistry).

Adolescent↗
PubMed1992

The neural and neuro-endocrine component of the human thymus. II. Hormone immunoreactivity.

We evaluated the presence of anterior pituitary hormones; follicle-stimulating hormone (FSH) and its beta-subunit (beta-FSH), luteinizing hormone (LH) and its beta-subunit (beta-LH), beta-subunit of thyroid-stimulating hormone (beta-TSH), adrenocorticotropic hormone (ACTH), growth hormone (GH), and prolactin (PRL); the placental hormone human chorionic gonadotropin (hCG); and somatostatin, in paraffin and frozen sections of the human thymus. Epithelial cells in the medulla were immunoreactive for most of these hormones, in varying density and intensity of labeling. The cells labeled varied from epithelial cells surrounding Hassall's corpuscles toward solitary cells or small epithelial aggregates in the medulla. FSH immunoreactivity did occur predominantly in epithelial cells of the cortex, in apparent contrast to the predominant medullary location of cells immunolabeled for beta-FSH. The epithelial nature of FSH-immunoreactive cells was confirmed by two-color immunohistochemistry with anti-keratin antibody. In addition to FSH, some epithelial cells in subcapsule and cortex were labeled by antibodies to beta-FSH, beta-LH, beta-TSH, ACTH, GH, and PRL. Some macrophage-like cells surrounded by a rosette of lymphocytes were immunoreactive for FSH and GH. Some interdigitating reticulum-like cells were labeled by anti-beta-LH. Immunolabeling of lymphocytes was found for hCG, especially lymphocytes in the medulla. Two-color immunohistochemistry with anti-CD3 revealed a strong CD3 expression on hCG-immunoreactive cells, whereas CD3-negative cells were hCG-negative. T cells immunolabeled for hCG were also found in peripheral lymphoid organs.

Adolescent↗
PubMed1991

Fatal disseminated hemorrhagic toxoplasmic encephalitis as the initial manifestation of AIDS.

A 28-year-old woman presented with progressive coma after being asymptomatic for 1 year after the demonstration of seropositivity for human immunodeficiency virus and high serum immunoglobulin G toxoplasma titers. Computed tomographic scanning showed multiple rounded cerebral hemorrhages and massive cerebral edema. Postmortem examination disclosed Toxoplasma gondii cysts scattered throughout the brain. An overwhelming fatal toxoplasmosis associated with multiple cerebral hemorrhages may be the first presentation of the acquired immunodeficiency syndrome. We raise the possibility that frequent neuroradiological monitoring may be indicated in asymptomatic human immunodeficiency virus-infected patients with high immunoglobulin G toxoplasma titers.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Cerebral medulloepithelioma--electron microscopy and immunohistochemistry.

A case is reported of a boy, 3 years of age, with a large medulloepithelioma in the left cerebral hemisphere. Medulloepitheliomas are rare tumors of the primitive medullar epithelium. Histological, immunohistochemical and electron microscopical findings are presented. We discuss previously reported cases, the ontogeny of this type of tumor and the relation to the so-called primitive neuro-ectodermal tumors (PNET).

Brain Neoplasms↗
PubMed1990

Polar spongioblastoma: an immunohistochemical and electron microscopical study.

A case is reported of a 9-year-old boy with a cerebral polar spongioblastoma. This neoplasm, first described by Russell and Cairns in 1947, is morphologically a distinct entity characterized by bipolar tumor cells with palisading nuclei. In the case under study immunoreactivity for neuron-specific enolase was found and ultrastructural features of developing neuronal elements were present. A neuro-endocrine nature was suggested by de Chadarévian et al. (1984) in a morphologically similar case. These findings are in contrast with the long-held view that the polar spongioblastoma is cytogenetically related to the embryonal radial glial cells.

Astrocytoma↗
PubMedDate not supplied

Alternative splicing of glutamate transporter EAAT2 RNA in neocortex and hippocampus of temporal lobe epilepsy patients.

RATIONALE: Altered expression of glutamate transporter EAAT2 protein has been reported in the hippocampus of patients with temporal lobe epilepsy (TLE). Two alternative EAAT2 mRNA splice forms, one resulting from a partial retention of intron 7 (I7R), the other from a deletion of exon 9 (E9S), were previously implicated in the loss of EAAT2 protein in patients with amyotrophic lateral sclerosis. METHODS: By RT-PCR we studied the occurrence of I7R and E9S in neocortical and hippocampal specimens from TLE patients and non-neurological controls. RESULTS: Both splice forms were found in all neocortical specimens from TLE patients (100% I7R, 100% E9S). This was significantly more than in controls (67% I7R, 60% E9S; P < 0.05). We also detected I7R and E9S in all seven motor cortex post-mortem samples from patients with amyotrophic lateral sclerosis. Within the TLE patient group, both splice variants appeared significantly more in non-sclerotic (100%), than in sclerotic hippocampi (69%, P < 0.05). CONCLUSION: These data indicate that the epileptic brain, especially that of TLE patients without hippocampal sclerosis, is highly prone to alternative EAAT2 mRNA splicing. Our data confirm that the presence of alternative EAAT2 splice forms is not disease specific.

Adult↗