Eosinophilic Polymyositis: A Rare Cause of Atraumatic Compartment Syndrome of the Forearm

Background  Eosinophilic polymyositis is a rare disorder in which eosinophils infiltrate muscle and supporting connective tissue structures, resembling autoimmune or immunologically mediated disease. This disorder can be associated with muscle inflammation and death, and can be a cause of atraumatic compartment syndrome. Methods  This is a retrospective chart review of a case report as well as review of pertinent literature. Results  This report presents a rare case of atraumatic compartment syndrome of the forearm caused by eosinophilic polymyositis. It provides a case summary and histological examination of this patient. Conclusion  This is an important case to report because it highlights eosinophilic polymyositis as a unique etiology of compartment syndrome. In appropriate clinical situations where patients do not improve despite standard interventions, one should consider the rare and unusual etiology of compartment syndrome due to eosinophilic polymyositis. Furthermore, primary surgical intervention should not be delayed while waiting to ascertain a definitive diagnosis.

Evaluation of the Structure of Myodural Bridges in an Equine Model of Ehlers-Danlos Syndromes

Myodural bridges have been described in various species as connective tissue structures “bridging” small cranio-cervical muscles to the dura. Myodural bridges are thought to stabilize the dural sac during head and neck movements and promote cerebrospinal fluid motion; however, their role in neurological diseases has not yet been established. We report ultrasonographic visualization, necropsy, histopathologic and ultrastructural findings of myodural bridges in horses with hereditary equine regional dermal asthenia (HERDA), an equine model of Ehlers-Danlos syndromes. Five HERDA and 5 control horses were studied. Post-mortem examination and ultrasonographic studies (3 HERDA and 4 controls) demonstrated that the atlanto-occipital and atlanto-axial myodural bridges are dynamic structures “moving” the dura. En block resection of the myodural bridges (4 HERDA and 5 controls) was accomplished and histopathology showed myofiber degeneration in 3 HERDA horses and 1 control. Ultrastructural examination revealed loosely packed collagen fibrils with abnormal orientation in all HERDA horses compared to mild abnormalities in 2 controls. Our study provides necropsy and ultrasonographic evidence of the dynamic aspect of the myodural bridges as dural sac stabilizers. Myodural bridges may be pathologically altered in connective tissue disease as evidenced by the ultrastructural morphology in the HERDA myodural bridge.

Counteracting the effects of TNF receptor-1 has therapeutic potential in Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia, and neuroinflammation is an important hallmark of the pathogenesis. Tumor necrosis factor (TNF) might be detrimental in AD, though the results coming from clinical trials on anti‐TNF inhibitors are inconclusive. TNFR1, one of the TNF signaling receptors, contributes to the pathogenesis of AD by mediating neuronal cell death. The blood–cerebrospinal fluid (CSF) barrier consists of a monolayer of choroid plexus epithelial (CPE) cells, and AD is associated with changes in CPE cell morphology. Here, we report that TNF is the main inflammatory upstream mediator in choroid plexus tissue in AD patients. This was confirmed in two murine AD models: transgenic APP/PS1 mice and intracerebroventricular (icv) AβO injection. TNFR1 contributes to the morphological damage of CPE cells in AD, and TNFR1 abrogation reduces brain inflammation and prevents blood–CSF barrier impairment. In APP/PS1 transgenic mice, TNFR1 deficiency ameliorated amyloidosis. Ultimately, genetic and pharmacological blockage of TNFR1 rescued from the induced cognitive impairments. Our data indicate that TNFR1 is a promising therapeutic target for AD treatment.

Immunohistochemical evaluation of apoptosis and proliferation in the mucous membrane of selected uterine regions in pre-pubertal bitches exposed to low doses of zearalenone

Mycotoxins are toxic secondary metabolites produced by fungi. Those biologically active compounds occur naturally and they include zearalenone (ZEN), a mycotoxin that contaminates plant material, including the ingredients used in the production of commercial dog food. The influence of monotonic, low-dose and long-term exposure to ZEN on pre-pubertal bitches has not been fully explored to date. This paper describes a 42-day experiment performed on clinically healthy female dogs aged approximately 70 days, with estimated body weight of 8 kg. The animals were randomly divided into two experimental groups (EI and EII) and a control group (C) of 10 animals each. Group EI received 50 μg ZEN/kg (of body weight) per os, group EII received 75 μg ZEN/kg BW per os, and the control group was administered placebo. The bitches were ovariohysterectomized at the end of the experiment (at around 112 days of age), and selected sections of the uterine wall were subjected to immunohistochemical analyses (TUNEL and PCNA). A shift towards higher apoptotic (AI) and proliferative index (PI) was observed, in particular in group EI. Higher AI and PI values were noted in the epithelium of all uterine regions analysed and in the uterine glands in the uterine horn proximal to the body of the uterus.

Alzheimer's therapeutics targeting amyloid beta 1-42 oligomers I: Abeta 42 oligomer binding to specific neuronal receptors is displaced by drug candidates that improve cognitive deficits

Synaptic dysfunction and loss caused by age-dependent accumulation of synaptotoxic beta amyloid (Abeta) 1-42 oligomers is proposed to underlie cognitive decline in Alzheimer's disease (AD). Alterations in membrane trafficking induced by Abeta oligomers mediates reduction in neuronal surface receptor expression that is the basis for inhibition of electrophysiological measures of synaptic plasticity and thus learning and memory. We have utilized phenotypic screens in mature, in vitro cultures of rat brain cells to identify small molecules which block or prevent the binding and effects of Abeta oligomers. Synthetic Abeta oligomers bind saturably to a single site on neuronal synapses and induce deficits in membrane trafficking in neuronal cultures with an EC50 that corresponds to its binding affinity. The therapeutic lead compounds we have found are pharmacological antagonists of Abeta oligomers, reducing the binding of Abeta oligomers to neurons in vitro, preventing spine loss in neurons and preventing and treating oligomer-induced deficits in membrane trafficking. These molecules are highly brain penetrant and prevent and restore cognitive deficits in mouse models of Alzheimer's disease. Counter-screening these compounds against a broad panel of potential CNS targets revealed they are highly potent and specific ligands of the sigma-2/PGRMC1 receptor. Brain concentrations of the compounds corresponding to greater than 80% receptor occupancy at the sigma-2/PGRMC1 receptor restore cognitive function in transgenic hAPP Swe/Ldn mice. These studies demonstrate that synthetic and human-derived Abeta oligomers act as pharmacologically-behaved ligands at neuronal receptors--i.e. they exhibit saturable binding to a target, they exert a functional effect related to their binding and their displacement by small molecule antagonists blocks their functional effect. The first-in-class small molecule receptor antagonists described here restore memory to normal in multiple AD models and sustain improvement long-term, representing a novel mechanism of action for disease-modifying Alzheimer's therapeutics.

A new look at cerebrospinal fluid circulation

According to the traditional understanding of cerebrospinal fluid (CSF) physiology, the majority of CSF is produced by the choroid plexus, circulates through the ventricles, the cisterns, and the subarachnoid space to be absorbed into the blood by the arachnoid villi. This review surveys key developments leading to the traditional concept. Challenging this concept are novel insights utilizing molecular and cellular biology as well as neuroimaging, which indicate that CSF physiology may be much more complex than previously believed. The CSF circulation comprises not only a directed flow of CSF, but in addition a pulsatile to and fro movement throughout the entire brain with local fluid exchange between blood, interstitial fluid, and CSF. Astrocytes, aquaporins, and other membrane transporters are key elements in brain water and CSF homeostasis. A continuous bidirectional fluid exchange at the blood brain barrier produces flow rates, which exceed the choroidal CSF production rate by far. The CSF circulation around blood vessels penetrating from the subarachnoid space into the Virchow Robin spaces provides both a drainage pathway for the clearance of waste molecules from the brain and a site for the interaction of the systemic immune system with that of the brain. Important physiological functions, for example the regeneration of the brain during sleep, may depend on CSF circulation.

Traumatic brain injury and recovery mechanisms: peptide modulation of periventricular neurogenic regions by the choroid plexus-CSF nexus

In traumatic brain injury (TBI), severe disruptions occur in the choroid plexus (CP)-cerebrospinal fluid (CSF) nexus that destabilize the nearby hippocampal and subventricular neurogenic regions. Following invasive and non-invasive injuries to cortex, several adverse sequelae harm the brain interior: (i) structural damage to CP epithelium that opens the blood-CSF barrier (BCSFB) to protein, (ii) altered CSF dynamics and intracranial pressure (ICP), (iii) augmentation of leukocyte traffic across CP into the CSF-brain, (iv) reduction in CSF sink action and clearance of debris from ventricles, and (v) less efficient provision of micronutritional and hormonal support for the CNS. However, gradual post-TBI restitution of the injured CP epithelium and ependyma, and CSF homeostatic mechanisms, help to restore subventricular/subgranular neurogenesis and the cognitive abilities diminished by CNS damage. Recovery from TBI is facilitated by upregulated choroidal/ependymal growth factors and neurotrophins, and their secretion into ventricular CSF. There, by an endocrine-like mechanism, CSF bulk flow convects the neuropeptides to target cells in injured cortex for aiding repair processes; and to neurogenic niches for enhancing conversion of stem cells to new neurons. In the recovery from TBI and associated ischemia, the modulating neuropeptides include FGF2, EGF, VEGF, NGF, IGF, GDNF, BDNF, and PACAP. Homeostatic correction of TBI-induced neuropathology can be accelerated or amplified by exogenously boosting the CSF concentration of these growth factors and neurotrophins. Such intraventricular supplementation via the CSF route promotes neural restoration through enhanced neurogenesis, angiogenesis, and neuroprotective effects. CSF translational research presents opportunities that involve CP and ependymal manipulations to expedite recovery from TBI.

The distributional nexus of choroid plexus to cerebrospinal fluid, ependyma and brain: toxicologic/pathologic phenomena, periventricular destabilization, and lesion spread

Bordering the ventricular cerebrospinal fluid (CSF) are epithelial cells of choroid plexus (CP), ependyma and circumventricular organs (CVOs) that contain homeostatic transporters for mediating secretion/reabsorption. The distributional pathway ("nexus") of CP-CSF-ependyma-brain furnishes peptides, hormones, and micronutrients to periventricular regions. In disease/toxicity, this nexus becomes a conduit for infectious and xenobiotic agents. The sleeping sickness trypanosome (a protozoan) disrupts CP and downstream CSF-brain. Piperamide is anti-trypanosomic but distorts CP epithelial ultrastructure by engendering hydropic vacuoles; this reflects phospholipidosis and altered lysosomal metabolism. CP swelling by vacuolation may occlude CSF flow. Toxic drug tools delineate injuries to choroidal compartments: cyclophosphamide (vasculature), methylcellulose (interstitium), and piperazine (epithelium). Structurally perturbed CP allows solutes to penetrate the ventricles. There, CSF-borne pathogens and xenobiotics may permeate the ependyma to harm neurogenic stem cell niches. Amoscanate, an anti-helmintic, potently injures rodent ependyma. Ependymal/brain regions near CP are vulnerable to CSF-borne toxicants; this proximity factor links regional barrier breakdown to nearby periventricular pathology. Diverse diseases (e.g., African sleeping sickness, multiple sclerosis) take early root in choroidal, circumventricular, or perivascular loci. Toxicokinetics informs on pathogen, anti-parasitic agent, and auto-antibody distribution along the CSF nexus. CVOs are susceptible to plasma-borne toxicants/pathogens. Countering the physico-chemical and pathogenic insults to the homeostasis-mediating ventricle-bordering cells sustains brain health and fluid balance.

Thyroid hormone levels in the prefrontal cortex of post-mortem brains of Alzheimer's disease patients

Converging evidence suggests a possible link between thyroid state and Alzheimer's disease (AD), including a higher probability of dementia in individuals with higher TSH levels and a two-fold risk of AD in patients with hypothyroidism. Thyroid hormones modulate factors associated with AD, including amyloid precursor protein expression in the brain, suggesting a possible role for thyroid hormone in AD pathology. The present study is the first to directly evaluate brain thyroid hormone levels in AD. Triiodothyronine (T(3)) and thyroxine (T(4)) levels were measured with radioimmunoassay (RIA) in post-mortem samples of prefrontal cortex of patients with pathologically confirmed AD, including Braak stage I-II (n=8), Braak stage V-VI (n=8), and controls without any primary neurological disease (n=8). T(4) levels did not differ between groups. T(3) levels were significantly lower in Braak stage V-VI brains relative to controls, but there was no statistically significant difference between T(3) levels in Braak stage I-II versus controls. Results suggest that the conversion of T(4) to T(3) may be affected in advanced AD, perhaps due to alterations in deiodinase activity. Reduced conversion of T(4) to T(3) in AD may be associated with both AD pathology and the clinical presentation of dementia.

Homeostatic capabilities of the choroid plexus epithelium in Alzheimer's disease

As the secretory source of vitamins, peptides and hormones for neurons, the choroid plexus (CP) epithelium critically provides substances for brain homeostasis. This distributive process of cerebrospinal fluid (CSF) volume transmission reaches many cellular targets in the CNS. In ageing and ageing-related dementias, the CP-CSF system is less able to regulate brain interstitial fluid. CP primarily generates CSF bulk flow, and so its malfunctioning exacerbates Alzheimers disease (AD). Considerable attention has been devoted to the blood-brain barrier in AD, but more insight is needed on regulatory systems at the human blood-CSF barrier in order to improve epithelial function in severe disease. Using autopsied CP specimens from AD patients, we immunocytochemically examined expression of heat shock proteins (HSP90 and GRP94), fibroblast growth factor receptors (FGFr) and a fluid-regulatory protein (NaK2Cl cotransporter isoform 1 or NKCC1). CP upregulated HSP90, FGFr and NKCC1, even in end-stage AD. These CP adjustments involve growth factors and neuropeptides that help to buffer perturbations in CNS water balance and metabolism. They shed light on CP-CSF system responses to ventriculomegaly and the altered intracranial pressure that occurs in AD and normal pressure hydrocephalus. The ability of injured CP to express key regulatory proteins even at Braak stage V/VI, points to plasticity and function that may be boosted by drug treatment to expedite CSF dynamics. The enhanced expression of human CP 'homeostatic proteins' in AD dementia is discussed in relation to brain deficits and pharmacology.

Effect of APOE genotype on microvascular basement membrane in Alzheimer's disease

APOE4 homozygosity has been associated with an increased risk of sporadic Alzheimer's disease through a mechanism, which has yet to be defined. Recent evidence has suggested that microvascular basement membrane injury may be a critical factor in the pathogenesis of AD-related dementia. In previous studies, we have shown that the synaptic organizing protein agrin can be found in neurons, and is a major component of the brain microvascular basement membrane. Here, we compare the basement membrane surface area of cortical microvasculature in AD brains by staining with an anti-agrin antibody. Quantitative morphometric analysis was used to determine the mean basement area (micro(2)) of prefrontal cortical microvessels. An average of 10 capillaries was measured in each of 35 cases of AD genotyped for APOE status. APOE4,4 homozygotes had smaller capillary basement membrane areas (17.4 micro(2))+/-6.2) than APOE3,3 homozygotes (26.9 micro(2)+/-6.5), p<0.001. The capillary basement membrane areas (CBMA) of heterozygotes APOE3,4 did not differ significantly from APOE3,3 or APOE4,4. Braak stage did not contribute significantly to CBMA. However, a preliminary analysis suggests an interaction between APOE4,4 and Braak V-VI producing smaller CBMA, a finding which needs to be confirmed with a larger sample. These data support the hypothesis that APOE4,4 is associated with thinning of the microvascular basement membrane in Alzheimer's disease.

Sinus pericranii: dermatologic considerations and literature review

Sinus pericranii is a rare disorder characterized by a congenital or acquired epicranial blood-filled nodule of the scalp that is in communication with an intracranial dural sinus through dilated diploic veins of the skull. We describe two patients with sinus pericranii: a 3-year-old boy with a congenital lesion and a 3-year-old girl whose lesion appeared after head trauma. We discuss the clinical presentation, dermatologic manifestations, differential diagnosis, and management as described in the available published literature. Patients with sinus pericranii may be brought to the attention of dermatologists and dermatopathologists because of skin changes in the scalp or forehead. The diagnosis is difficult to make clinically, because the skin manifestations are highly variable and may resemble other disorders of the scalp and cranium. The potentially lethal complications including hemorrhage, infection, and air embolism warrant a high index of suspicion for sinus pericranii.

Adult-onset MELAS. Evidence for involvement of neurons as well as cerebral vasculature in strokelike episodes

BACKGROUND

We report a 46-year-old woman with implications regarding pathogenesis of strokelike episodes in MELAS (mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes). She had a 10-month history of episodic seizures, strokes, cognitive decline, vomiting, and ileus. She also had sensorineural hearing loss, insulin-dependent diabetes mellitus of several years' duration, and persistent lactic acidosis. Family history was pertinent for a similar syndrome in her deceased mother (onset in her sixties), for hearing loss and diabetes mellitus in two brothers, and for hearing loss in her only child, a son.

CASE DESCRIPTION

Serial MRIs of the brain revealed severe but evanescent cerebral cortical abnormalities. A left temporal brain biopsy was performed to exclude encephalitis. Light microscopy revealed a diffuse fibrillary gliosis with abundant reactive gemistocytes, focal evidence of ischemic neuronal injury, and edema. Electron microscopy revealed bizarre enlarged mitochondria and changes consistent with cellular edema. Succinate dehydrogenase staining was strongly reactive within cerebral blood vessels and within neurons. A point mutation was subsequently found at nt 3243 of the mitochondrial tRNA(Leu(UUR) gene in peripheral leukocytes and in brain, confirming the clinical diagnosis of MELAS. Quantitation revealed that 82% of brain mitochondria carried the disease mutation, indicating that most, if not all, tissues were affected.

CONCLUSIONS

Our findings suggest that strokelike episodes in MELAS result from defects in neuronal metabolism, as well as in cerebral vasculature.

Monoclonal B-cell population mimicking lymphoma in a patient with multiple sclerosis

BACKGROUND

Diagnosis of intraparenchymal brain lesions has usually required invasive diagnostic procedures, because too few cells are shed into cerebrospinal fluid to permit cytologic diagnosis. Polymerase chain reaction technology makes it possible to identify cell populations that are present at a much lower frequency than traditional techniques.

CASE REPORT

A young woman presented with multiple brain lesions raised the question of primary central nervous system lymphoma. Polymerase chain reaction analysis of cerebrospinal fluid showed evidence of a monoclonal B-cell population heightening suspicion of lymphoma. Brain biopsy showed acute demyelination most consistent with multiple sclerosis.

CONCLUSION

Although T-cell restriction has been demonstrated in multiple sclerosis lesions, the finding of a monoclonal B-cell population was unexpected and to our knowledge has not been previously reported. This case emphasizes that monoclonality is not always indicative of a neoplastic process, particularly in the central nervous system.

Phase I study of weekly outpatient paclitaxel and concurrent cranial irradiation in adults with astrocytomas

PURPOSE

Astrocytomas are extremely resistant to currently available treatments. Cranial irradiation is a mainstay of frontline therapy, but tumor recurrence is nearly universal. Paclitaxel has shown antitumor efficacy against astrocytoma cell lines, and is a potent radiosensitizer. For these reasons, we conducted a phase I study of weekly paclitaxel and concurrent cranial irradiation in patients with newly diagnosed astrocytomas.

PATIENTS AND METHODS

Patients with astrocytomas were eligible for this study following initial surgery if they had a Karnofsky performance score (KPS) > or = 60%; normal hematologic, liver, and renal function; and could give informed consent. Beginning on day 1 of treatment, patients received paclitaxel by 3-hour infusion once weekly for 6 weeks, concurrent with standard cranial irradiation. Pharmacokinetic studies were performed on 10 patients.

RESULTS

Sixty patients were enrolled; 56 were fully assessable. Forty-eight had glioblastomas (GBMs), 10 anaplastic astrocytomas (AAs), and two astrocytomas. Age ranged from 21 to 81 years (median, 55); KPS ranged from 60 to 100 (median, 70). The paclitaxel dose was escalated from 20 mg/m2 to 275 mg/m2. No clinically significant anemia or thrombocytopenia occurred. Only one patient (175 mg/m2) became neutropenic. Sensory neuropathy was dose-limiting. The maximum tolerated dose (MTD) was 250 mg/m2. Paclitaxel pharmacokinetic profiles in study patients were identical to those of previously reported patients with other solid tumors.

CONCLUSION

The MTD of paclitaxel administered weekly for 6 weeks by 3-hour infusion is 250 mg/m2. Since patients with brain tumors often have preexisting neurologic deficits, we suggest 225 mg/m2 as the optimum dose for phase II trials in this group of patients.

Advanced glycation end products contribute to amyloidosis in Alzheimer disease

Alzheimer disease (AD) is characterized by deposits of an aggregated 42-amino-acid beta-amyloid peptide (beta AP) in the brain and cerebrovasculature. After a concentration-dependent lag period during in vitro incubations, soluble preparations of synthetic beta AP slowly form fibrillar aggregates that resemble natural amyloid and are measurable by sedimentation and thioflavin T-based fluorescence. Aggregation of soluble beta AP in these in vitro assays is enhanced by addition of small amounts of pre-aggregated beta-amyloid "seed" material. We also have prepared these seeds by using a naturally occurring reaction between glucose and protein amino groups resulting in the formation of advanced "glycosylation" end products (AGEs) which chemically crosslink proteins. AGE-modified beta AP-nucleation seeds further accelerated aggregation of soluble beta AP compared to non-modified "seed" material. Over time, nonenzymatic advanced glycation also results in the gradual accumulation of a set of posttranslational covalent adducts on long-lived proteins in vivo. In a standardized competitive ELISA, plaque fractions of AD brains were found to contain about 3-fold more AGE adducts per mg of protein than preparations from healthy, age-matched controls. These results suggest that the in vivo half-life of beta-amyloid is prolonged in AD, resulting in greater accumulation of AGE modifications which in turn may act to promote accumulation of additional amyloid.

Light selectively alters vasoactive intestinal peptide and peptide histidine isoleucine immunoreactivity within the rat suprachiasmatic nucleus

The concentration of vasoactive intestinal peptide (VIP)-, peptide histidine isoleucine (PHI)-, neurotensin (NT)- and substance P (SP)-like immunoreactivity (LI) within the suprachiasmatic nucleus (SCN) were determined by radioimmunoassay in rats housed in LD 14:10 h, constant light or constant dark. No day-night differences were observed in the concentration of VIP-, PHI-, NT- or SP-LI within the SCN. Exposure to constant light significantly depressed the SCN concentrations of VIP- and PHI-LI, but had no significant effects on SCN concentrations of NT- or SP-LI, or VIP- or PHI-LI concentrations within the cortex. These data represent the first evidence that VIP/PHI-containing neurons may be involved in mediating photic information within the SCN.

Fludarabine phosphate (NSC 312878) infusions for the treatment of acute leukemia: phase I and neuropathological study

Fludarabine phosphate (NSC 312878), an adenosine deaminase resistant analogue of 9-beta-D-arabinofuranosyladenine, has entered clinical trials. Eleven patients with acute leukemia in relapse received 14 courses of fludarabine phosphate as a 5-day continuous infusion administered at doses of 40 to 100 mg/m2/day. Toxicity was characterized by uniform myelosuppression, as well as occasional nausea, vomiting, and hepatotoxicity. Three episodes of metabolic acidosis and lactic acidemia were noted. In addition, three patients suffered neurotoxicity. Two of these three patients had a severe neurotoxicity syndrome characterized by blindness, encephalopathy, and coma. Neither patient recovered neurological function. Neuropathological findings at autopsy were characterized by a diffuse, necrotizing leukoencephalopathy which was most severe in the occipital lobes. The medullary pyramids and posterior columns were also severely affected. This sporadic fatal neurotoxicity was observed only at doses greater than 40 mg/m2/day. The maximum tolerated dose for a 5-day infusion of fludarabine phosphate is thus 40 mg/m2/day.