Biased suppression of hematopoiesis and multiple developmental defects in chimeric mice containing Shp-2 mutant cells.

Shp-2 is a cytoplasmic tyrosine phosphatase that contains two Src homology 2 (SH2) domains at the N terminus. Biochemical data suggests that Shp-2 acts downstream of a variety of receptor and cytoplasmic tyrosine kinases. A targeted deletion mutation in the N-terminal SH2 (SH2-N) domain results in embryonic lethality of homozygous mutant mice at midgestation. In vitro embryonic stem (ES) cell differentiation assays suggest that Shp-2 might play an important role in hematopoiesis. By aggregating homozygous mutant (Shp-2(-/-)) ES cells and wild-type (WT) embryos, we created Shp-2(-/-)-WT chimeric animals. We report here an essential role of Shp-2 in the control of blood cell development. Despite the widespread contribution of mutant cells to various tissues, no Shp-2(-/-) progenitors for erythroid or myeloid cells were detected in the fetal liver and bone marrow of chimeric animals by using the in vitro CFU assay. Furthermore, hematopoiesis was defective in Shp-2(-/-) yolk sacs. In addition, the Shp-2 mutation caused multiple developmental defects in chimeric mice, characterized by short hind legs, aberrant limb features, split lumbar vertebrae, abnormal rib patterning, and pathological changes in the lungs, intestines, and skin. These results demonstrate a functional involvement of Shp-2 in the differentiation of multiple tissue-specific cells and in body organization. More importantly, the requirement for Shp-2 is more stringent in hematopoiesis than in other systems.

Mechanisms of enhanced insulin sensitivity in endurance-trained athletes: effects on blood flow and differential expression of GLUT 4 in skeletal muscles.

Exercise is associated with increased insulin sensitivity. To better understand mechanisms that could be responsible for this association, we studied seven controls and seven endurance-trained athletes. A 600 mU/m2.min hyperinsulinemic euglycemic glucose clamp with the limb balance technique assessed insulin sensitivity as whole body glucose uptake (WBGU) and leg glucose uptake (LGU). Indirect calorimetry and hemodynamic measurements, such as leg blood flow (LBF) and cardiac output, were performed at baseline and maximal insulin stimulation. The content of the glucose transporter GLUT 4 and muscle fiber type were evaluated in three muscle groups: vastus lateralis, gastrocnemius, and biceps. Athletes exhibited 35% higher WBGU and 30% higher LGU than controls. Basal LBF (liters per min) was higher in athletes, but the difference was not statistically significant. After insulin stimulation, LBF was 31% higher in athletes than controls (P = 0.05). Indirect calorimetry revealed that athletes had a 44% higher rate of nonoxidative glucose metabolism than controls (P = 0.01). GLUT 4 levels in vastus were 90% (P < 0.05) greater in athletes, whereas smaller differences were noted between athletes and controls in biceps and gastrocnemius. Importantly, the vastus lateralis GLUT 4 content was correlated with WBGU (r = 0.60; P < 0.05) and LGU (r = 0.62; P < 0.05). Relative numbers of oxidative fibers were increased in vastus from athletes and were positively correlated with maximal oxygen consumption (VO2 max), but GLUT 4 content could not be correlated with oxidative fiber content in individual controls or athletes. We conclude that in humans 1) endurance training enhances insulin's ability to increase LBF; 2) GLUT 4 is differentially expressed as a function of muscle group and is up-regulated by exercise in a muscle-specific manner; 3) in vastus lateralis, GLUT 4 levels are well correlated with insulin-stimulated rates of both WBGU and LGU; and 4) GLUT 4 content and in vivo insulin sensitivity do not vary as a function of fiber type composition. Thus, blood flow and GLUT 4 expression in muscle are important mechanisms that mediate greater insulin sensitivity in athletes.

The A-1 antigen: a novel marker in experimental peripheral nerve injury.

Expression of the Schwann cell phenotype is regulated by signals from the adjoining axon. After axotomy, the Schwann cell ceases the production and maintenance of the myelin sheath and assumes phagocytic properties necessary to digest its own myelin. The molecular mechanisms responsible for this behavior remain unclear. A monoclonal antibody termed BIKS was produced after the immunization of mice with guinea pig lymphoid tissue. This antibody recognizes a cytoplasmic vesicle-associated molecule (A-1 antigen) which is abundant in all tissue macrophages but is also expressed in small amounts in normal Schwann cells. Following axotomy, the A-1 antigen appears to be translocated from a perinuclear site to accumulate in large quantities around myelin ovoids in Schwann cells, as well at the nodes of Ranvier-sites where Wallerian degeneration is known to commence. The level of the antigen remains high when axons are prevented from regeneration. During repair of crush injury, however, the level of antigen drops concomitant with the ingrowth of regenerating axons, suggesting axonal control of A-1 antigen expression.

Cerebral phlebothrombosis. A complication of lymphoma.

A patient with malignant lymphoma died as the result of cerebral phlebothrombosis. The presence of "leukostasis" restricted to the CNS associated with venous necrosis is a possible mechanism leading to venous thrombosis.

Diffuse "anoxic" myelopathy.

Pathologic changes and distribution of lesions of the spinal cord were studied in 16 patients who suffered from "anoxic" episodes. The lesions were symmetrical and limited to the gray matter. The vulnerability of the spinal cord was most marked in the lumbosacral region, although almost every nucleus throughout the spinal cord was subject to damage.

Shy-Drager syndrome: diagnosis and treatment of cholinergic dysfunction.

Two patients with Shy-Drager syndrome demonstrated unusually widespread and unequivocal cholinergic dysfunction as well as the usual evidence of adrenergic insufficiency. Progressive constipation preceded impotence, nocturia, hesitancy in micturition, anhidrosis, orthostatic hypotension, and xerostomia. Nonautonomic neurologic signs appeared several years later. Cholinergic dysfunction involved eyes, lacrimal glands, salivary glands, heart, gastrointestinal tract, urinary bladder, and sweat glands. Subcutaneous administration of bethanechol chloride--a muscarinic receptor agonist--improved tearing, salivation, sweating, and gastrointestinal and bladder functions. Daily administration of this drug resulted in symptomatic improvement of the autonomic functions, and relapse followed discontinuation of treatment.

Gerstmann-Sträussler-Scheinker disease. I. Extending the clinical spectrum.

We present the clinical findings in affected members of a large kindred with Gerstmann-Sträussler-Scheinker disease. Sixty-four patients exhibited progressive ataxia, dementia, and parkinsonian features. Inheritance appears to be autosomal dominant. Impaired smooth-pursuit eye movements, defective short-term memory, clumsiness of the hands, and ataxia of gait develop in the late 30s to early 60s. Eye movement abnormalities are characteristic of cerebellar dysfunction. Dementia progresses gradually over several years. Later, rigidity and bradykinesia appear and, at this stage, there is often psychosis or severe depression with rapid weight loss. Death occurs in 6 months to 2 years after onset of rigidity. Magnetic resonance imaging in 2 affected individuals showed cerebellar atrophy. There is decreased T2 signal in the basal ganglia, consistent with iron deposition.

Gerstmann-Sträussler-Scheinker disease. II. Neurofibrillary tangles and plaques with PrP-amyloid coexist in an affected family.

Azzarelli et al reported an Indiana kindred affected by a hereditary disorder, characterized clinically by ataxia, parkinsonism, and dementia. Recently, we studied neuropathologically the 3rd and 4th cases that came to autopsy among the patients of this family. As in 2 patients examined previously, amyloid plaques were widespread throughout the cerebrum and the cerebellum, whereas neurofibrillary tangles were numerous in the cerebral cortex, the hippocampus, and the substantia innominata. Amyloid plaques were not recognized by polyclonal antibodies against the Alzheimer's disease amyloid A4 protein, but did contain epitopes recognized by antibodies against a prion protein. Spongiform changes were occasionally observed and were mild. Our findings indicate that this familial disorder is a form of or is related to Gerstmann-Sträussler-Scheinker disease. The consistent presence of numerous neurofibrillary tangles may be important in differentiating a distinct subgroup of patients with familial Gerstmann-Sträussler-Scheinker disease, and indicates that a disturbance of the cytoskeleton might be part of the neuronal pathology of Gerstmann-Sträussler-Scheinker disease.

Early detection of canine ceroid-lipofuscinosis (CCL): an ultrastructural study.

English setters from the Koppang line have been used as a model for the juvenile type of Batten disease in human patients. This disorder, canine ceroid-lipofuscinosis (CCL), has been shown by Koppang [1973: Mech Ageing Dev 2:421-445] to be an autosomal recessive disorder. Homozygous animals show the typical storage granules by autofluorescence; however, the autofluorescence material cannot easily be detected in affected dogs before age 3-6 months. At the present time the early stages of CCL can be studied only in litters from homozygous matings. Electron microscopy was used to study the reliability of diagnosing affected animals in heterozygous-heterozygous (HET-HET) and heterozygous-homozygous (HET-HOM) litters at age 2-3 weeks. The electron micrographs of brain biopsies were examined and the number of all dense bodies (d.b.), including linear and fingerprint patterns typical of CCL, were counted per neuron. The results indicated that affected animals have higher numbers of dense bodies than nonaffected carriers. Four-6 months later confirmatory diagnoses were made on a second contralateral biopsy taken and examined as a frozen section by autofluorescence. The diagnoses made by electron microscopy at age 2-3 weeks appeared identical to the results obtained by autofluorescence at 4-6 months of age.

Neuro-ophthalmic, radiographic, and pathologic manifestations of adult-onset Alexander disease.

A 61-year-old woman had a 3-year history of imbalance. Eye movement studies revealed square-wave jerks, gaze paretic nystagmus, rebound nystagmus, impaired smooth pursuit, impaired optokinetic nystagmus, and abnormal fixation suppression of vestibular nystagmus. A brain magnetic resonance imaging study showed extensive areas of increased signal from the middle cerebellar peduncles and dentate nuclei, which enhanced with gadolinium. Histopathological analysis of a needle biopsy specimen of the left cerebellar peduncle revealed diffuse gliosis in the presence of symmetrically distributed areas of demyelination. There were associated Rosenthal fibers. Clinicopathologic correlation supported a diagnosis of Alexander disease. An adult patient with a history of progressive imbalance, ocular motility abnormalities consistent with cerebellar and/or brainstem dysfunction, and diffuse, symmetric hyperintense magnetic resonance imaging signals in brainstem and cerebellar white matter should suggest a diagnosis of adult-onset Alexander disease.

Extrarenal Wilms' tumor with cerebellar metastasis in a four-year-old girl with spina bifida.

This report documents the occurrence of an extrarenal nephroblastoma from which a cerebellar metastasis developed in a four-year-old girl with spina bifida. The second tumor became symptomatic two years after the resection of the primary, suggesting a treatment effect as a factor for the delay in the growing of the metastatic neoplasm. Histologic and ultrastructural features of the metastasis were similar to those described in Wilms' tumors of the kidney. The pathogenesis of this exceptional association, including malformation, malignancy, and unusual site of metastasis, is discussed.

Gd-enhanced MR imaging of acute and chronic experimental demyelinating lesions.

Experimental allergic encephalomyelitis, a demyelinating disease with marked similarity to multiple sclerosis, was produced in two of 12 dogs. All dogs were studied with serial MR imaging. T1- and T2-weighted MR images were obtained both before and after IV Gd-DTPA. Multiple, new periventricular white matter demyelinating lesions were observed after each clinical episode of the disease. Like multiple sclerosis, the acute lesions of experimental allergic encephalomyelitis on T2-weighted MR images were indistinguishable from the older, more chronic lesions. However, after Gd-DTPA, there was bright paramagnetic enhancement of the acute lesions and, in one animal, no enhancement of the chronic lesions on T1-weighted MR images. At necropsy, the differences in the MR paramagnetic enhancement correlated well with the relative histologic age of the demyelinating lesions. Our results suggest that MR with Gd-DTPA may be used to differentiate acute, active demyelinating lesions from the more chronic, inactive lesions in this animal model.

Multiple fusiform intracranial aneurysms following curative radiation therapy for suprasellar germinoma. Case report.

A 17-year-old girl died from the rupture of a large fusiform aneurysm of the terminal internal carotid artery. Autopsy revealed three other fusiform aneurysms originating from major cerebral arteries clearly within the ports of previously administered telecobalt radiation therapy. Five years prior to her death, a suprasellar germinoma was partially removed and the area was treated by radiation therapy via three ports. The original arteriograms showed a normal vascular tree. Repeat arteriograms, 3 years and 8 months before her death, demonstrated the aneurysms. The development of aneurysms following radiation damage of the arteries has been reported previously, but not in intracranial vessels.

Primary intravascular lymphomatosis associated with Mycobacterium marinum.

Intravascular lymphomatosis (i.v.l.) is a rare condition in which neoplastic cells preferentially infiltrate blood vessels of the central nervous system. Nonspecific symptoms associated with i.v.l. include dementia, seizures, and multifocal cerebrovascular events. i.v.l. was discovered at autopsy of a patient whose neurological deficits were predated by a particularly aggressive form of Mycobacterium marinum soft-tissue infection. It is speculated that i.v.l. may have had an occult effect on the patient's cell-mediated immunity that predisposed him to this normally innocuous mycobacteria.

Dopamine in paragangliomas of the glomus jugulare.

Glomus jugulare tumors have the ability to synthesize, store, and secrete biogenic amines. Although the majority of these tumors remain endocrinologically silent, on rare occasions they present either as a pheochromocytoma or with a carcinoid syndrome. We report a 20-year-old male with two intracranial tumors: an intrasellar neoplasm and a glomus jugulare tumor. Catecholamine catabolites in the urine were not increased, and blood pressure was always normal. The pituitary tumor was an adenoma, immunostaining positive for prolactin. The second patient, a 29-year-old hypertensive male, with a glomus jugulare tumor, had increased vanillylmandelic-acid excretion. In both cases, the paraganglioma tumor cells contained numerous dense-core vesicles (125 to 380 nm in diameter) in electron microscopy, and showed intense fluorescence by the sucrose-potassium phosphate-glyoxylic acid method. Using high-performance liquid chromatography and microspectrofluorometry we were able to establish the presence of large amounts of dopamine in the cytoplasm of the tumor cells.

Recurrence in pituitary adenomas in childhood and adolescence.

Pediatric pituitary adenomas are thought to behave more aggressively than their adult counterparts, and the ability to predict the degree of such behavior remains elusive. Proliferation marker Ki-67 and tumor suppressor gene p53 mutations have been used in adults to assist in the evaluation of invasiveness and recurrence; however, their use in childhood and adolescence remains anecdotal. Our study evaluates the proliferative potential in pituitary adenomas of five patients and its relationship with recurrence or persistence of endocrinologic or clinical abnormalities. For such assessment, tissues were stained with monoclonal antibodies BP53-12 forp53 tumor suppressor gene mutation and MIB-1, which binds to cell cycle-specific nuclear antigen Ki-67. In our series, one patient with recurrent adenoma demonstrated the highest (50%) p53 immunoreactivity. Ki-67-stained nuclei ranged from 0 to 2%, failing to identify the recurrent tumor. Therefore, p53 immunoreactivity, rather than Ki-67 nuclear stain, may be useful for identification of recurrent pituitary adenomas in childhood and adolescence.

Hypoxic-ischemic encephalopathy in areas of primary myelination: a neuroimaging and PET study.

The stage of regional structural and biochemical development of the central nervous system appears as a critical factor determining the distribution of hypoxic-ischemic lesions during the perinatal period. We describe the brain lesions in 12 patients who suffered hypoxia-ischemia during the perinatal period. The gestational age ranged from 35 to 42 weeks and the age at death from 2 to 16 weeks. There is one patient alive at age 18 years and a second patient at age 1 year. The cerebral cortical damage is mainly restricted to areas of primary myelination and adjacent subcortical white matter. In addition, there is thalamic, basal ganglia, brainstem, and spinal cord damage. It is postulated that selective damage occurs in those areas which at the moment of the hypoxic-ischemic insult had achieved higher rates of oxygen-glucose utilization. This hypothesis is supported by studies utilizing positron emission tomography which indicates that glucose utilization in the normal human neonatal brain follows a phylogenetic order. Regions that achieved higher levels of glucose consumption are those that suffered the brunt of the damage in our term neonates.

Presurgical evaluation and surgical outcome of temporal lobe epilepsy.

The authors analyzed 22 patients younger than 18 years of age with temporal lobe epilepsy (TLE) treated surgically. Patients underwent a comprehensive presurgical evaluation, including video-electroencephalogram. Fifty-five percent had a history of febrile seizures. Eighty-two percent had auraes and most exhibited oroalimentary and gestural automatisms. Contralateral dystonic posturing was present in 36% and postictal dysphasia in 54% of patients with left-sided resections. Cranial magnetic resonance imaging (MRI) was abnormal in 59% of patients. MRI revealed changes consistent with mesial temporal sclerosis in 8 (47%) of 17 patients without lesions. Fluorodeoxyglucose-positron emission tomography (PET) scans revealed ipsilateral temporal hypometabolism (PET-TH) in 12 (85.7%) of 14 patients. The intracarotid amobarbital procedure revealed impaired memory of the epileptogenic side in 59% of patients. Seventeen patients underwent en-bloc resections and five lesionectomies and resection of the epileptogenic area. There was no surgical morbidity or mortality. Forty-three percent had hippocampal sclerosis, 28.5% gliosis, 14% low-grade tumors, 9.5% cavernous angiomas, and 5% had no pathologic findings. Follow-up (6 months to 12 years) was available for 21 patients; 76% became seizure free, 19% had rare seizures, and 5% had a worthwhile improvement. TLE can be safely treated surgically in younger patients with excellent results. The clinical manifestations were similar to adult patients. PET-TH was present even at a younger age, suggesting that the focal functional deficits appear early in patients with medically refractory TLE, which may help in the early identification of these patients.

A morphologic study of intracerebral hemorrhage in a case of acute leukemia.

Morphologic studies have thus far failed to demonstrate the nature of the vessel involved in the brain hemorrhages of patients with acute leukemia. A detailed study of such hemorrhages was carried out in a patient with leukemic phase of mycosis fungoides. Plastic-embedded lesions showed that blast cells blocked the lumen of the capillary, leading to severe dilation and rupture of the vessel. The rheologic properties of blast cells in vessels of critical diameters seem to be an important factor in the pathogenesis of intracerebral hemorrhages.

Flow cytometric DNA analysis of pediatric intracranial ependymomas.

OBJECTIVE: To examine the clinicopathologic features and perform flow cytometric DNA analysis of pediatric intracranial ependymomas to determine whether any of these parameters were predictors of clinical outcome. METHODS: Flow cytometric DNA analysis was performed on 17 paraffin-embedded tumors from patients aged 7 months to 16 years. RESULTS: Seven cases were aneuploid, while the remaining 10 were diploid. Proliferative fractions varied from 1% to 17%. CONCLUSIONS: No correlation between histologic features such as mitotic activity, cellularity, pleomorphism, vascular proliferation, and length of survival was observed. However, the presence of a diploid DNA stemline, elevated proliferative fraction, or young age were associated with a poor clinical outcome and shortened survival times (P < 0.05). Additional studies of larger patient groups with extended follow-up are necessary to confirm these findings.