A Case Report of a Novel Atypical Mycobacterial Infection: Mycobacterium Chimaera Hand Tenosynovitis

CASE

A 76-year-old fisherman with a history of diabetes mellitus, coronary artery bypass grafting, and a previous ipsilateral elbow wound presented with a 1-year history of hand pain and swelling. Anti-inflammatories and antibiotics were administered without improvement. Magnetic resonance imaging and ultrasound demonstrated flexor tenosynovitis. Intraoperative cultures revealed Mycobacterium chimaera. The treatment course included 2 tenosynovectomies and a 1-year course of triple antimycobacterial therapy.

CONCLUSION

Nontuberculous mycobacteria infections should be considered in cases of indolent tenosynovitis. M. chimaera should be considered in patients with a history of cardiopulmonary bypass given its association with cardiopulmonary heater-cooler units.

Papillary glioneuronal tumors: Distinctive cytological characteristics and cyto-histologic correlation

Intraoperative cytological examination and cyto-histologic correlation of papillary glioneuronal tumors have rarely been described in detail in the literature. A 23-year-old female presented at our institution with seizure-like activity, and a 3.0 cm left temporal lobe hypoattenuating lesion. She was accurately diagnosed with papillary glioneuronal tumor on Intraoperative cytology. The patient subsequently proceeded to stealth-guided awake left temporal craniotomy, confirming the diagnosis. In this article, we present a detailed report of papillary glioneuronal tumor (extremely rare central nervous system neoplasm) describing the cytologic and histologic morphologic features, its differential diagnosis with review of the literature.

Progressing Bevacizumab-Induced Diffusion Restriction Is Associated with Coagulative Necrosis Surrounded by Viable Tumor and Decreased Overall Survival in Patients with Recurrent Glioblastoma

BACKGROUND AND PURPOSE

Patients with recurrent glioblastoma often exhibit regions of diffusion restriction following the initiation of bevacizumab therapy. Studies suggest that these regions represent either diffusion-restricted necrosis or hypercellular tumor. This study explored postmortem brain specimens and a population analysis of overall survival to determine the identity and implications of such lesions.

MATERIALS AND METHODS

Postmortem examinations were performed on 6 patients with recurrent glioblastoma on bevacizumab with progressively growing regions of diffusion restriction. ADC values were extracted from regions of both hypercellular tumor and necrosis. A receiver operating characteristic analysis was performed to define optimal ADC thresholds for differentiating tissue types. A retrospective population study was also performed comparing the overall survival of 64 patients with recurrent glioblastoma treated with bevacizumab. Patients were separated into 3 groups: no diffusion restriction, diffusion restriction that appeared and progressed within 5 months of bevacizumab initiation, and delayed or stable diffusion restriction. An additional analysis was performed assessing tumor O⁶-methylguanine-DNA-methyltransferase methylation.

RESULTS

The optimal ADC threshold for differentiation of hypercellularity and necrosis was 0.736 × 10^-3mm²/s. Progressively expanding diffusion restriction was pathologically confirmed to be coagulative necrosis surrounded by viable tumor. Progressive lesions were associated with the worst overall survival, while stable lesions showed the greatest overall survival (P < .05). Of the 40% of patients with O⁶-methylguanine-DNA-methyltransferase methylated tumors, none developed diffusion-restricted lesions.

CONCLUSIONS

Progressive diffusion-restricted lesions were pathologically confirmed to be coagulative necrosis surrounded by viable tumor and associated with decreased overall survival. Stable lesions were, however, associated with increased overall survival. All lesions were associated with O⁶-methylguanine-DNA-methyltransferase unmethylated tumors.

Silicon detectors for combined MR-PET and MR-SPECT imaging

Silicon based devices can extend PET-MR and SPECT-MR imaging to applications, where their advantages in performance outweigh benefits of high statistical counts.Silicon is in many ways an excellent detector material with numerous advantages, among others: excellent energy and spatial resolution, mature processing technology, large signal to noise ratio, relatively low price, availability, versatility and malleability. The signal in silicon is also immune to effects of magnetic field at the level normally used in MR devices. Tests in fields up to 7 T were performed in a study to determine effects of magnetic field on positron range in a silicon PET device. The curvature of positron tracks in direction perpendicular to the field's orientation shortens the distance between emission and annihilation point of the positron. The effect can be fully appreciated for a rotation of the sample for a fixed field direction, compressing range in all dimensions. A popular Ga-68 source was used showing a factor of 2 improvement in image noise compared to zero field operation. There was also a little increase in noise as the reconstructed resolution varied between 2.5 and 1.5 mm.A speculative applications can be recognized in both emission modalities, SPECT and PET.Compton camera is a subspecies of SPECT, where a silicon based scatter as a MR compatible part could inserted into the MR bore and the secondary detector could operate in less constrained environment away from the magnet. Introducing a Compton camera also relaxes requirements of the radiotracers used, extending the range of conceivable photon energies beyond 140.5 keV of the Tc-99m.In PET, one could exploit the compressed sub-millimeter range of positrons in the magnetic field. To exploit the advantage, detectors with spatial resolution commensurate to the effect must be used with silicon being an excellent candidate. Measurements performed outside of the MR achieving spatial resolution below 1 mm are reported.

Silicon as an Unconventional Detector in Positron Emission Tomography

Positron emission tomography (PET) is a widely used technique in medical imaging and in studying small animal models of human disease. In the conventional approach, the 511 keV annihilation photons emitted from a patient or small animal are detected by a ring of scintillators such as LYSO read out by arrays of photodetectors. Although this has been a successful in achieving ~5mm FWHM spatial resolution in human studies and ~1mm resolution in dedicated small animal instruments, there is interest in significantly improving these figures. Silicon, although its stopping power is modest for 511 keV photons, offers a number of potential advantages over more conventional approaches. Foremost is its high spatial resolution in 3D: our past studies show that there is little diffculty in localizing 511 keV photon interactions to ~0.3mm. Since spatial resolution and reconstructed image noise trade off in a highly non-linear manner that depends on the PET instrument response, if high spatial resolution is the goal, silicon may outperform standard PET detectors even though it has lower sensitivity to 511 keV photons. To evaluate silicon in a variety of PET "magnifying glass" configurations, an instrument has been constructed that consists of an outer partial-ring of PET scintillation detectors into which various arrangements of silicon detectors can be inserted to emulate dual-ring or imaging probe geometries. Recent results have demonstrated 0.7 mm FWHM resolution using pad detectors having 16×32 arrays of 1.4mm square pads and setups have shown promising results in both small animal and PET imaging probe configurations. Although many challenges remain, silicon has potential to become the PET detector of choice when spatial resolution is the primary consideration.

Consequences of stopping and restarting leptin in an adolescent with lipodystrophy

BACKGROUND/AIMS

Lipodystrophy encompasses a group of rare disorders characterized by deficiency of adipose tissue resulting in hypoleptinemia, and metabolic abnormalities including insulin resistance, diabetes, dyslipidemia, and nonalcoholic steatohepatitis. Leptin replacement effectively ameliorates these metabolic derangements. We report effects of leptin discontinuation and resumption in a child with acquired generalized lipodystrophy.

METHODS

Intermittent treatment with leptin with follow-up over 5 years.

RESULTS

Pretreatment metabolic abnormalities included insulin resistance, hypertriglyceridemia and steatohepatitis. Leptin was started at the age of 10 years. After 2 years, the family requested discontinuation of leptin due to lack of visible physical changes. Nine months later, worsened metabolic abnormalities and arrest of pubertal development were observed. Leptin was restarted, followed by improvements in metabolic parameters. Laboratory changes (before vs. 6 months after restarting leptin) were: fasting glucose from 232 to 85 mg/dl, insulin from 232 to 38.9 µU/ml, HbA(1c) from 7.5 to 4.8%, triglycerides from 622 to 96 mg/dl, ALT from 229 to 61 U/l, AST from 91 to 18 U/l, and urine protein:creatinine ratio from 5.4 to 0.3. Progression of puberty was observed 1 year after restarting leptin.

CONCLUSION

Initial leptin therapy likely prevented progression of metabolic abnormalities. Treatment discontinuation led to rapid metabolic decomposition and pubertal arrest. Reintroduction of leptin reversed metabolic abnormalities and allowed normal pubertal progression.

Founder effect in the Horn of Africa for an insulin receptor mutation that may impair receptor recycling

AIMS/HYPOTHESIS

Genetic insulin receptoropathies are a rare cause of severe insulin resistance. We identified the Ile119Met missense mutation in the insulin receptor INSR gene, previously reported in a Yemeni kindred, in four unrelated patients with Somali ancestry. We aimed to investigate a possible genetic founder effect, and to study the mechanism of loss of function of the mutant receptor.

METHODS

Biochemical profiling and DNA haplotype analysis of affected patients were performed. Insulin receptor expression in lymphoblastoid cells from a homozygous p.Ile119Met INSR patient, and in cells heterologously expressing the mutant receptor, was examined. Insulin binding, insulin-stimulated receptor autophosphorylation, and cooperativity and pH dependency of insulin dissociation were also assessed.

RESULTS

All patients had biochemical profiles pathognomonic of insulin receptoropathy, while haplotype analysis revealed the putative shared region around the INSR mutant to be no larger than 28 kb. An increased insulin proreceptor to β subunit ratio was seen in patient-derived cells. Steady state insulin binding and insulin-stimulated autophosphorylation of the mutant receptor was normal; however it exhibited decreased insulin dissociation rates with preserved cooperativity, a difference accentuated at low pH.

CONCLUSIONS/INTERPRETATION

The p.Ile119Met INSR appears to have arisen around the Horn of Africa, and should be sought first in severely insulin resistant patients with ancestry from this region. Despite collectively compelling genetic, clinical and biochemical evidence for its pathogenicity, loss of function in conventional in vitro assays is subtle, suggesting mildly impaired receptor recycling only.

Timing performance of the silicon PET insert probe

Simulation indicates that PET image could be improved by upgrading a conventional ring with a probe placed close to the imaged object. In this paper, timing issues related to a PET probe using high-resistivity silicon as a detector material are addressed. The final probe will consist of several (four to eight) 1-mm thick layers of silicon detectors, segmented into 1 x 1 mm(2) pads, each pad equivalent to an independent p + nn+ diode. A proper matching of events in silicon with events of the external ring can be achieved with a good timing resolution. To estimate the timing performance, measurements were performed on a simplified model probe, consisting of a single 1-mm thick detector with 256 square pads (1.4 mm side), coupled with two VATAGP7s, application-specific integrated circuits. The detector material and electronics are the same that will be used for the final probe. The model was exposed to 511 keV annihilation photons from an (22)Na source, and a scintillator (LYSO)-PMT assembly was used as a timing reference. Results were compared with the simulation, consisting of four parts: (i) GEANT4 implemented realistic tracking of electrons excited by annihilation photon interactions in silicon, (ii) calculation of propagation of secondary ionisation (electron-hole pairs) in the sensor, (iii) estimation of the shape of the current pulse induced on surface electrodes and (iv) simulation of the first electronics stage. A very good agreement between the simulation and the measurements were found. Both indicate reliable performance of the final probe at timing windows down to 20 ns.

SEPT5_v2 is a parkin-binding protein

Mutations in parkin are associated with various inherited forms of Parkinson's disease (PD). Parkin is a ubiquitin ligase enzyme that catalyzes the covalent attachment of ubiquitin moieties onto substrate proteins destined for proteasomal degradation. The substrates of parkin-mediated ubiquitination have yet to be completely identified. Using a yeast two-hybrid screen, we isolated the septin, human SEPT5_v2 (also known as cell division control-related protein 2), as a putative parkin-binding protein. SEPT5_v2 is highly homologous to another septin, SEPT5, which was recently identified as a target for parkin-mediated ubiquitination. SEPT5_v2 binds to parkin at the amino terminus and in the ring finger domains. Several lines of evidence have validated the putative link between parkin and SEPT5_v2. Parkin co-precipitates with SEPT5_v2 from human substantia nigra lysates. Parkin ubiquitinates SEPT5_v2 in vitro, and both SEPT5_v1 and SEPT5_v2 accumulate in brains of patients with ARJP, suggesting that parkin is essential for the normal metabolism of these proteins. These findings suggest that an important relationship exists between parkin and septins.

Co-association of parkin and alpha-synuclein

Parkin and alpha-synuclein are two proteins that are associated with the pathophysiology of Parkinson's disease (PD). Parkin is present in Lewy bodies and axonal spheroids in brains affected by PD, and mutations in parkin cause hereditary forms of Parkinsonism. Alpha-synuclein is a major component of Lewy bodies and is associated with rare cases of PD. We now show that parkin binds to alpha-synuclein, including conditions associated with alpha-synuclein aggregation. Parkin and alpha-synuclein complexes were observed in BE-M17 cells under basal conditions, in BE- M17 cells under oxidative conditions and in brains from control or PD donors. Double staining of PD brains shows parkin and alpha-synuclein co-localize to the same pathological structures (both Lewy bodies and axonal spheroids). These results suggest that parkin interacts with alpha-synuclein and could contribute to the pathophysiology of PD more generally than was previously considered.

Ballistic-choreic movements as the presenting feature of renal cancer

BACKGROUND

The paraneoplastic syndromes can involve multiple areas of the central nervous system and result in a variety of neurological symptoms. To our knowledge, severe, rapidly progressive, and drug-resistant ballistic-choreic movements have not been previously described as the presenting feature of renal cell carcinoma.

PATIENT AND METHODS

A previously healthy 55-year-old man developed limb ballismus and involuntary choreic movements of his face over several weeks. Extensive laboratory, diagnostic, and radiographic studies failed to reveal a cause, until an abnormality on a chest x-ray film prompted a search for a primary neoplasm and a final diagnosis of renal cell carcinoma. High doses of medications traditionally used to treat choreic disorders had no effect on the abnormal movements. A biopsy specimen of the basal ganglia showed focal encephalitic changes but no malignant neoplasm.

CONCLUSIONS

Whereas prior cases of paraneoplastic syndromes with chorea have been reported in other forms of cancer, our case was significant because, to our knowledge, renal cell carcinoma has not been previously reported in association with this syndrome. Furthermore, the chorea was categorically resistant to pharmacological treatment, and the movement disorder was the initial and only focal neurological feature of the primary illness.

Parkin is metabolized by the ubiquitin/proteosome system

Mutations in the parkin gene cause autosomal recessive juvenile parkinsonism. Immunostaining of substantia nigra sections from sporadic Parkinson's disease (PD) cases shows that Parkin accumulates in axonal spheroids and in some Lewy bodies. Because ubiquitin is a major component of Lewy bodies and axonal spheroids, we investigated whether Parkin is metabolized via the ubiquitin/proteosomal pathway. Treatment of BE-M17 neuroblastoma cells with the proteosomal inhibitor, MG132, produced a band corresponding to di-ubiquitinated Parkin that was apparent by immunoblot using two different anti-Parkin antibodies. This higher mol. wt band also co-immunoprecipitated with Parkin. These data suggest that Parkin plays a role in the pathophysiology of sporadic PD, and that Parkin is a substrate for ubiquitination that is degraded by the proteosomal complex.

Distal internal carotid artery pseudoaneurysms: technique and pitfalls of surgical management: two technical case reports

OBJECTIVE AND IMPORTANCE

Small, irregular aneurysms of the internal carotid artery (ICA) that are not related to arterial divisions are rare and have characteristics similar to pseudoaneurysms: they do not appear to have well-formed sacs, they are surrounded by clot, and they avulse readily. We report two patients whose treatment demonstrates the surgical technique and important points concerning the management of distal ICA pseudoaneurysms.

CLINICAL PRESENTATION

Both patients presented with diffuse subarachnoid hemorrhage. The initial angiographic results were unremarkable in each case. A week after presentation, however, a growing outpouching in the distal ICA was seen.

INTERVENTION

At surgery, the aneurysms were found to be on the medial wall of the ICA and were not related to arterial divisions. Quantitative blood flow measurements of the efferent vessels at risk (ICA, M1 and A1 segments) were obtained using a perivascular microflowprobe before and after clipping. In each patient, the aneurysm avulsed entirely during clip application, despite careful placement of the clip parallel to the parent vessel. An encircling clip was then used. Pathological sectioning of the aneurysms revealed loose connective tissue and/or clot with no defined aneurysmal sac.

CONCLUSION

Aneurysms of the distal ICA that are not related to arterial divisions are difficult to visualize on angiograms immediately after subarachnoid hemorrhage. They are frail, avulse easily, and may be pseudoaneurysms, necessitating the use of encircling clips. The base of the aneurysm or clot must be trimmed to prevent it from buckling inside the clip sleeve and compromising the ICA lumen. Measuring distal blood flow quantitatively provides valuable information about the patency of the ICA inside the metallic sleeve, since this segment cannot be demonstrated with angiography.

Hepatocyte growth factor/scatter factor promotes a switch from E- to N-cadherin in chick embryo epiblast cells

Epiblast cells downregulate E-cadherin and upregulate N-cadherin as they ingress through the primitive streak and when placed in culture. The factors that promote the alteration in cadherin expression during gastrulation are unknown. The effects of hepatocyte growth factor/scatter factor (HGF/SF) on cadherin expression were tested in cultures of prestreak epiblast cells. HGF/SF decreased the expression of E-cadherin and increased the percentage of cells with N-cadherin and sarcomeric myosin. Cells with N-cadherin but not E-cadherin differentiated into skeletal muscle. HGF/SF also stimulated proliferation and the formation of cellular aggregates. Sensitivity to HGF/SF in vitro depended on the original position of cells within the epiblast. More cells from the lateral epiblast switched cadherins and proliferated in response to HGF/SF than medial epiblast cells. HGF/SF may affect gastrulation by altering cadherin expression, modulating cell adhesion, and stimulating proliferation within the epiblast.

Late-onset sporadic progressive subcortical gliosis

We report two sporadic cases of progressive subcortical gliosis (PSG) with onset after age 60. The presentation included slowly progressive dementia with memory loss, geographic disorientation, and personality change. Both were diagnosed clinically as Alzheimer's disease (AD) and both met NINCDS-ADRDA criteria for probable AD. Autopsy revealed generalized atrophy, predominantly involving the white matter of the frontal and temporal lobes. Microscopically, prominent fibrillary astrocytosis was present in the subcortical white matter and in the subpial and deep layers of the overlying cerebral cortex. Mild cortical neuron loss accompanied the gliosis, but no myelin loss was evident. Amyloid deposits and neuronal cytoskeletal inclusions were absent.

Amyloid beta precursor protein and ubiquitin epitopes in human and experimental dystrophic axons. Ultrastructural localization

Dystrophic axons (DA) represent a major pathological feature of several neurodegenerative disorders, including infantile neuroaxonal dystrophy (INAD) and Alzheimer disease. We have previously presented evidence that amyloid beta precursor protein (BPP) and ubiquitin (Ub) are present in DA of different origin. We have now characterized the immunoreactivity of DA experimentally induced in rat by the administration of parabromophenylacetylurea (BPAU) and examined the subcellular localization of Ub and BPP in BPAU-induced DA and in DA present in subjects affected by INAD. BPAU-induced DA strongly immunoreacted with antisera to Ub and to COOH- and NH2-terminal regions of BPP. Immunoblots of DA-enriched brain regions were consistent with an increase in the amount of Ub and BPP in DA. Moreover, BPAU-induced DA immunoreacted with antibodies to PGP 9.5, a neuronal-specific Ub COOH-terminal hydrolase, and to the inducible heat shock protein 70. Antigenic characterization also indicated that the tubulovesicular membranes within DA derived largely from the smooth endoplasmic reticulum rather than from the Golgi system or the synaptic vesicles. Subcellular immunolocalization of Ub and BPP in both INAD- and BPAU-induced DA revealed that Ub and BPP colocalize in granulovesicular material in both conditions. In INAD DA intense Ub immunoreactivity was also detected in nonmembranous electron dense structures that were present only in these DA, probably because of the chronic course of INAD. Although BPP immunostaining may be related to accumulation of BPP-containing membranes in DA, Ub immunostaining is likely to result from activation of the Ub system by the neuron in the attempt to remove excessive and possibly abnormal proteins. A similar pathogenesis can be postulated for DA of Alzheimer disease.

Galaninergic innervation of the cholinergic vertical limb of the diagonal band (Ch2) and bed nucleus of the stria terminalis in aging, Alzheimer's disease and Down's syndrome

The galanin (GAL) containing peptide fiber system circuit which innervates acetylcholine containing basal forebrain neurons has been shown to hypertrophy and hyperinnervate remaining cholinergic Ch4 perikarya in Alzheimer's disease (AD). The present study examined whether a similar hyperinnervation occurs within the cholinergic vertical limb of the diagonal band nucleus (Ch2), a portion of the basal forebrain which, unlike Ch4, exhibits only modest degeneration in AD. Furthermore, we evaluated whether GAL hyperinnervation occurs within the basal forebrain in Down's syndrome, a genetic disorder with extensive AD-like pathology including cholinergic basal forebrain neuron degeneration. The present study revealed that virtually all Ch2 neurons were GAL immunonegative. However, this region was innervated by GAL immunoreactive (ir) interneurons and fibers associated with a major galaninergic pathway which travels through the substantia innominata enroute to the hypothalamus, bed nucleus of the stria terminalis as well as vertical limb of diagonal band nucleus. GAL-ir fibers coursing within this fiber bundle hypertrophied in AD relative to age matched controls and the Down's cases. Within the putative Ch2 terminal zones in AD, many of the remaining cholinergic neurons were hyperinnervated by GAL despite the modest reduction in Ch2 neurons. In contrast, GAL-ir fibers were not hypertrophied in Down's syndrome despite extensive cholinergic cell loss within Ch4. Taken together these findings suggest that extensive cholinergic basal forebrain cell loss alone is not sufficient to trigger the basal forebrain GAL plasticity response found in AD.

Amyloid precursor protein and ubiquitin immunoreactivity in dystrophic axons is not unique to Alzheimer's disease

A distinctive feature of Alzheimer's disease (AD) is the presence of dystrophic neurites that immunoreact with antibodies to amyloid precursor protein (APP) and ubiquitin (Ub). The authors examined dystrophic axons (DA) present in other chronic conditions such as familial infantile neuroaxonal dystrophy (INAD), aging, cystic fibrosis, and biliary obstruction as well as in conditions of shorter duration such as human immunodeficiency virus (HIV) leucoencephalopathy, infarction and radiation therapy to determine whether APP and Ub immunoreactivity was unique to the DA of AD. A large number of DA immunoreacted with antibodies to the A4, C- and N-terminal regions of APP as well as to Ub. Ub and APP immunoreactivities often, but not always, colocalized. "Acute" DA generally reacted more intensely and in larger number with antibodies to APP than to Ub, whereas the reverse was true for "chronic" DA. Structureless DA immunostained diffusely. In DA with cores or granules, the Ub immunoreaction was occasionally limited to these structures, whereas reaction with antibodies to APP was more diffuse. In view of the contention that impairment of proteolysis is the common pathogenetic step in the formation of DA, Ub immunoreactivity in all DA may indicate a vicarious attempt to degrade accumulated components through an activation of the Ub system. The role of APP in the formation of DA remains to be determined.

Putative chromaffin cell survival and enhanced host-derived TH-fiber innervation following a functional adrenal medulla autograft for Parkinson's disease

We report heretofore undescribed clinical and histological features of a patient with idiopathic Parkinson's disease who showed marked and persistent motoric benefit from an adrenal medulla autograft for 18 months following grafting. The patient returned to the preoperative level of disability prior to his death 30 months after implantation, the longest survival to date for an adrenal transplant. The graft site was primarily necrotic and large numbers of macrophages were still present at the time of death. A few tyrosine hydroxylase-immunoreactive cells were found within the graft, providing the first evidence that adrenal medullary cells may be viable and produce catecholamines following human transplantation. A dense network of tyrosine hydroxylase-immunoreactive terminals and processes was also seen ventral to the implant site and on both of its lateral borders. This response may represent sprouting by residual host dopaminergic neurons mediated by the vigorous response to injury displayed by the host striatum. The relative paucity of surviving chromaffin cells, however, provides further evidence that adrenal medulla grafts survive poorly following intracerebral implantation, and factors other than dopamine replacement may be responsible for most of the functional effects observed following chromaffin cell transplantation.

Regional serotonin levels in brain: a comparison of depressive suicides and alcoholic suicides with controls

The levels of 5-hydroxytryptamine have been measured in 33 areas of the human brain and these levels compared in depressed suicides, in alcoholic suicides, and in controls. The values obtained for control brains ranged from 5.3 mumole 5-HT/kg wet weight in substantia nigra to 0.4 mumole 5-HT/kg wet weight in frontal gray. No significant differences were found among diagnostic groups in any of the areas studied.