Reversible encephalopathy after cardiac transplantation: histologic evidence of endothelial activation, T-cell specific trafficking, and vascular endothelial growth factor expression

Reversible encephalopathy after transplantation is well recognized. The condition is commonly thought to be related to immune suppression, and a characteristic brain imaging pattern is typically recognized with vasogenic edema in the parietal and occipital regions, typically termed posterior reversible encephalopathy syndrome (PRES). We report the case of a patient with reversible encephalopathy after cardiac transplantation with brain biopsy evidence of endothelial activation, selective intravascular/perivascular T-cell trafficking, and VEGF expression in astrocytes, neurons, and the endothelium.

Visual evoked potentials in infants exposed to methadone in utero

We investigated the effects of maternal drug misuse on neonatal visual evoked potentials (VEPs). Flash VEPs were recorded within 4 days of birth from 21 term infants of mothers misusing drugs and prescribed substitute methadone and 20 controls. Waveforms were classified as typical, atypical, immature or non-detectable, and amplitude and latencies were measured. VEPs from drug-exposed infants were less likely to be of typical waveform and more likely to be immature or non-detectable (p<0.01) than those of control infants. They were also smaller in amplitude (median 10.8 vs 24.4 microV, p<0.001). VEPs of drug-exposed infants had matured after 1 week but remained of lower amplitude than VEPs of newborn controls (p<0.01) and were non-detectable in 15%. Flash VEPs differ between maternal drug-exposed and non-drug-exposed newborns. Future research should address the specific effects of maternal methadone and/or other illicit drug misuse on infant VEPs, and associations between neonatal VEPs and subsequent visual development.

Case of the month. September 1996--new onset hemiparesis

A 44 year old woman developed left hemiparesis. CT scan showed a contrast enhancing lesion in the right periventricular area. A stereotactic biopsy was performed. The initial impression was that of an astrocytic neoplasm, however the presence of perivascular lymphocytes and numerous foamy macrophages led to consultation. Special studies demonstrated demyelination and lymphocytic infiltrate with relative axonal preservation consistent with multiple sclerosis. Additional history from the patient revealed a flu-like illness one week prior to the hemiparesis and a history of transitory visual problems, possibly early manifestations of her multiple sclerosis.

Case of the month. August 1996--frontal lobe tumor in 11 year old girl

An 11 year old girl presented with an 8 month history of left temporal headaches with new onset of nausea and vomiting with increased severity of headaches. An MRI scan showed a frontal lobe mass. The tumor was resected and histologic studies demonstrated a central neurocytoma. The clinical, radiologic and pathologic aspects (including immunohistochemistry and electron microscopy) of central neurocytomas are reviewed and the atypical features of this case described.

Case of the month. July 1996--precocious puberty

A 4 year old girl presented with precocious puberty. She had pubic hair, breast buds and showed a height and weight well above the 95th percentile. An MRI scan of the head revealed a discrete mass in the tuber cinereum which was surgically removed. Microscopic examination showed a hypothalamic hamartoma. The clinical, radiologic and microscopic findings in this case are "classic" for hypothalamic hamartoma Other clinical presentations are discussed. The patient's symptoms have regressed following surgery and there has been no regrowth in six months.

A randomized controlled study of human Day 3 embryo cryopreservation by slow freezing or vitrification: vitrification is associated with higher survival, metabolism and blastocyst formation

BACKGROUND

The aim of this study was to compare two methods of cryopreservation for the cleavage-stage human embryo: slow freezing and vitrification.

METHODS

A total of 466 Day 3 embryos, donated with consent, underwent cryopreservation by either slow freezing in straws or vitrification using the cryoloop. The vitrification procedure did not include dimethyl sulfoxide, but rather employed ethylene glycol and 1,2-propanediol as the cryoprotectants. Survival, embryonic metabolism and subsequent development to the blastocyst were used to determine the efficacy of the two procedures.

RESULTS

Significantly, more embryos survived the vitrification procedure (222/234, 94.8%) than slow freezing (206/232, 88.7%; P < 0.05). Consistent with this observation, pyruvate uptake was significantly greater in the vitrification group, reflecting a higher metabolic rate. Development to the blastocyst was also higher following vitrification (134/222, 60.3%) than following freezing (106/206, 49.5%; P < 0.05). In a separate cohort of 73 patients who had their supernumerary embryos cyropreserved with vitrification, the resulting implantation rate and clinical pregnancy rate were 30 and 49%, respectively.

CONCLUSIONS

Analysis of metabolism revealed that vitrification had less impact on the metabolic rate of the embryo than freezing, which was reflected in higher survival rate and subsequent development in vitro. Excellent pregnancy outcomes followed the warming and transfer of vitrified cleavage-stage embryos. These data provide further evidence that vitrification imparts less trauma to cells and is, therefore, a more effective means of cryopreserving the human embryo than conventional slow freezing. Clinicaltrials.gov identifier: NCT00608010.

February 1997--9 year old girl with hydrocephalus

A nine year old girl presented with nausea vomiting and hydrocephalus. Imaging studies demonstrated a large right thalamic mass with areas of cystic change or necrosis. Sections of resected material showed perivascular pseudorosettes, necrosis, endothelial proliferation, numerous mitoses, densely cellular areas and numerous foci with a clear-cell morphology. This case is used to illustrate the features of anaplastic ependymomas and to discuss the relationship of the histologic features to prognosis.

The molecular biology of ependymomas

Intracranial ependymomas are the third most common primary brain tumor in the pediatric population. Although an anaplastic variant is recognized, numerous studies examining the prognostic implications of histological features, such as necrosis, endothelial proliferation and mitoses, have yielded contradictory results. In order to improve outcome prediction in affected patients and to refine therapeutic decision-making, there is a strong need for identifying relevant biological correlates of tumor behavior. The molecular biology of tumors is a rapidly expanding field and includes investigations into cytogenetics, oncogenes, growth factors, growth factor receptors, hormonal receptors, proliferation markers, apoptosis, cell cycle genes and cell adhesion molecules, as well as factors potentially related to therapeutic resistance, such as the multidrug resistance gene. The molecular biology of astrocytic tumors in adults has been the subject of many studies; however, relatively few studies have been focused on ependymomas. Herein we review potential oncological markers in ependymomas that have been identified to date and highlight the limitations of our current knowledge as a basis for defining areas for future investigation.

January 1997--7 year old girl with seizures

A seven year old girl presented with six month history of seizures. An MRI scan showed a cortical lesion in the left temporal lobe which was resected. Neuropathologic examination demonstrated meningioangiomatosis, an unusual hamartomatous condition sometimes associated with neurofibromatosis 2. Approximately 50 cases of meningioangiomatosis have been reported in the literature. These are reviewed and compared to the current case.

December 1996--cervicomedullary tumor

A cervicomedullary tumor in a 22-month-old female with an eight-month history of symptoms showed the histological features of a pilocytic astrocytoma but had many areas of palisading cells identical to those described in polar spongioblastomas. The tumor recurred 18 months later and showed predominately pilocytic features. The case is used to discuss polar spongioblastomas and tumors which can histologically simulate them.

Species dependent differences in the actions of sympathetic nerves and noradrenaline in the internal anal sphincter

Excitatory motor innervation to the internal anal sphincter (IAS) of the monkey, the rabbit and mouse were compared. Contractile responses to electrical field stimulation of nerves (EFS, atropine 1 micromol L(-1) and N(omega)-nitro-L-arginine 100 micromol L(-1) present throughout) were examined in isolated strips of IAS. In the monkey IAS, EFS caused frequency dependent (1-30 Hz) contractions which were abolished by guanethidine (10 micromol L(-1)) or phentolamine (3 micromol L(-1)). The sympathetic neurotransmitter noradrenaline (NA) also caused concentration-dependent (10 nmol L(-1)-100 micromol L(-1)) contractions which were abolished by phentolamine revealing a small relaxation that was abolished by propranolol (3 micromol L(-1)). In contrast, EFS caused only relaxation of the mouse and rabbit IAS which was not affected by guanethidine. Furthermore, NA relaxed these muscles and relaxation was nearly abolished by combined addition of phentolamine and propranolol. In conclusion, the monkey IAS is functionally innervated by sympathetic nerves that contract the muscle via excitatory alpha-adrenergic receptors. In contrast, no significant motor function could be identified for sympathetic nerves in the rabbit or mouse IAS although adrenergic receptors linked to muscle inhibition are present. These data reveal species dependent differences in sympathetic motor innervation and suggest that some species are more appropriate than others as models for motor innervation to the human IAS.

The luminance-response function of the human photopic electroretinogram: a mathematical model

The luminance-response function of the brief flash full-field photopic electroretinogram (ERG) rises to a peak before falling to a sub-maximal plateau -- the 'photopic hill'. The combination of on- and off-responses inherent in the brief flash photopic ERG suggests that this luminance-response function could be modelled by the sum of a Gaussian function and a logistic growth function. Photopic ERGs to a luminance series of brief flashes against three different background luminances recorded from seven healthy adults showed the characteristic 'photopic hill' function for b-wave amplitudes which were satisfactorily fitted with the sum of a Gaussian curve and a logistic growth curve. As background luminance increased, both components shifted to the right on the luminance axis. The Gaussian component increased in amplitude while the logistic growth function component decreased in amplitude. The luminance-response function of a complete congenital stationary night blindness patient had almost no logistic growth component.

Negative ERGs in mucopolysaccharidoses (MPS) Hurler–Scheie (I-H/S) and Hurler (I-H)-syndromes

The configuration and progression of the ERG in two children with mucopolysaccharidosis (MPS) I H/S (Hurler-Scheie syndrome) and MPS I H (Hurler syndrome) is described. Physical examination, biochemical analysis, ophthalmic examination and electroretinography were performed. The Hurler-Scheie patient (case 1) showed negative scotopic but normal photopic ERGs, which remained unchanged over 2 years. The Hurler patient (case 2) showed negative scotopic and photopic ERGs which did not alter after bone marrow transplantation (BMT). One year after BMT, further b-wave amplitude reduction had caused the ERGs to become more negative. The electronegative configuration of the ERGs suggests that, in these cases of MPS, the primary retinal abnormality in MPS I may be faulty synaptic transmission from photoreceptors to more proximal elements, deficient bipolar responsivity, or Muller cell disease. Further degradation with time suggests the defect to be progressive with BMT causing little or no improvement. In the Hurler-Scheie syndrome case, the defect appears to spare the cone system and to show little or no progression.

Non-invasive assessment of tumor proliferation using triple quantum filtered 23/Na MRI: technical challenges and solutions

We address the development of triple-quantum-filtered sodium MRI as a non-invasive surrogate measure for cell proliferation in brain tumors. We demonstrate that through careful consideration of the theoretical description of the signal, triple-quantum-filtered sodium images of adequate signal-to-noise ratio (SNR) can be acquired in clinically acceptable imaging times.