The impact of blood pressure variability on the development of parenchymal hematoma in acute cerebral infarction with atrial fibrillation

Although blood pressure variability (BPV) and reperfusion are associated with parenchymal hematoma (PH) after stroke, the relationship between BPV and PH in atrial fibrillation (AF) patients who are at risk of reperfusion injury with frequent spontaneous recanalization is unknown. This study aimed to investigate whether BPV within the first 48 h is associated with PH within 72 h in patients with AF and stroke in terms of major vessel occlusion status. A total of 131 patients with AF that were admitted within 24 h after stroke onset were enrolled. PH was defined as a confluent hemorrhage with mass effect. The maximum (max), minimum (min), and average blood pressure (BP) during the first 48 h after admission were calculated. BPV was analyzed by using range between maximum and minimum (max-min), successive variation (SV), standard deviation (SD), and coefficient of variation (CV). All parameters were applied for systemic (SBP), diastolic (DBP), and pulse pressure (PP). After adjusting for confounding variables, various BPV parameters were associated with PH, including SBPmax (p = 0.0426), SBPSV (p = 0.0006), DBPmax-min (p = 0.0437), DBPSV (p = 0.0358), DBPSD (p = 0.0393), PPmax-min (p = 0.0478), PPSV (p < 0.0001), PPSD (p = 0.0034), and PPCV (p = 0.0120). The relationship remained significant in patients with a patent major vessel responsible for infarction but not in patients with an occluded major vessel. In conclusion, this study revealed that high BPV was associated with PH in patients with AF and acute stroke, particularly for those with a patent major vessel. The control of BP and BPV after stroke may be considered in patients with AF.

Predicting Adverse Recanalization Therapy Outcomes in Acute Ischemic Stroke Patients Using Characteristic Gut Microbiota

Recanalization therapy is the most effective treatment for eligible patients with acute ischemic stroke (AIS). Gut microbiota are involved in the pathological mechanisms and outcomes of AIS. However, the association of gut microbiota features with adverse recanalization therapy outcomes remains unclear. Herein, we investigated gut microbiota features associated with neurological deficits in patients with AIS after recanalization therapy and whether they predict the patients' functional outcomes. We collected fecal samples from 51 patients with AIS who received recanalization therapy and performed 16S rRNA gene sequencing (V3-V4). We compared the gut microbiota diversity and community composition between mild to moderate and severe disability groups. Next, the characteristic gut microbiota was compared between groups, and we noted that the characteristic gut microbiota in patients with mild to moderate disability included Bilophila, Butyricimonas, Oscillospiraceae_UCG-003, and Megamonas. Moreover, the relative abundance of Bacteroides fragilis, Fusobacterium sp., and Parabacteroides gordonii was high in patients with severe disability. The characteristic gut microbiota was correlated with neurological deficits, and areas under the receiver operating characteristic curves confirmed that the characteristic microbiota predicted adverse recanalization therapy outcomes. In conclusion, gut microbiota characteristics are correlated with recanalization therapy outcomes in patients with AIS. Gut microbiota may thus be a promising biomarker associated with early neurological deficits and predict recanalization therapy outcomes.

The Prognostic Biomarkers of Plasma Trimethylamine N-Oxide and Short-Chain Fatty Acids for Recanalization Therapy in Acute Ischemic Stroke

Bidirectional communication of the microbiota-gut-brain axis is crucial in stroke. Recanalization therapy, namely intravenous thrombolysis (IVT) and endovascular thrombectomy (EVT), are recommended for eligible patients with acute ischemic stroke (AIS). It remains unclear whether gut microbiota metabolites, namely trimethylamine N-oxide (TMAO) and short-chain fatty acids (SCFAs), can predict the prognosis after recanalization therapy. This prospective study recruited patients with AIS receiving IVT, EVT, or both. The National Institutes of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS) scores were used to assess the severity and functional outcomes of AIS, respectively. A functional outcome of mild-to-moderate disability was defined as a mRS score of 0-3 at discharge. Plasma TMAO and SCFA levels were measured through liquid chromatography with triple-quadrupole mass spectrometry. Fifty-six adults undergoing recanalization therapy for AIS were enrolled. Results showed that TMAO levels were not associated with stroke severity and functional outcomes, while isovalerate levels (one of the SCFAs) were negatively correlated with NIHSS scores at admission and discharge. In addition, high isovalerate levels were independently associated with a decreased likelihood of severe disability. The study concluded that an elevated plasma isovalerate level was correlated with mild stroke severity and disability after recanalization therapy for AIS.

Association between proteinuria and the development of malignant middle cerebral artery infarction: A retrospective cohort study

A disrupted blood-brain barrier (BBB) with extravasation of macromolecules plays a critical role in the development of malignant middle cerebral artery infarction (MMI). Proteinuria is considered a marker of generalized endothelial dysfunction, including BBB disruption. This study aimed to clarify whether proteinuria identified in the acute stage of stroke is associated with MMI development. Patients with infarctions involving the middle cerebral artery territory were reviewed. Urine samples collected within 8 hours after stroke were analyzed using urine dipsticks. Patients were divided into proteinuria (urine dipstick reading of 1 + to 4+) and nonproteinuria groups. MMI was present if either signs of uncal herniation or a progressive conscious disturbance were recorded along with a midline shift > 5 mm identified on follow-up computed tomography (CT). Among the 1261 patients identified between January 2010 and June 2019, 138 were eligible for final analyses. Patients in the MMI group had lower Alberta Stroke Program Early CT Scores (ASPECTS), higher National Institutes of Health Stroke Scale scores, and a greater proportion of proteinuria than those in the non-MMI group. Four multivariate logistic regression models were used to clarify the role of proteinuria in MMI development. In model 1, proteinuria was significantly associated with MMI after adjusting for age, sex, dyslipidemia and ASPECTS (OR = 2.987, 95% CI = 1.329-6.716, P = .0081). The risk of developing MMI in patients with proteinuria remained significant in model 2 (OR = 3.066, 95% CI = 1.349-6.968, P = .0075) after adjusting for estimated glomerular filtrate rate (eGFR) < 60ml/min/1.73 m2 in addition to variables in model 1. In model 3, proteinuria was still significantly associated with MMI after adjusting for age, sex, dyslipidemia, ASPECTS, hypertension, diabetes, and atrial fibrillation (OR = 2.521, 95% CI = 1.075-5.912, P = .0335). In model 4, the risk of developing MMI in patients with proteinuria remained significant (OR = 2.579, 95% CI = 1.094-6.079, P = .0304) after adjusting for eGFR < 60ml/min/1.73 m2 in addition to variables in model 3. Proteinuria is independently associated with MMI development. Proteinuria may be a clinically accessible predictor of MMI development.

UMOD Mutations in Chronic Kidney Disease in Taiwan

UMOD is the first identified and the most commonly mutated gene that causes autosomal dominant tubulointerstitial kidney disease (ADTKD). Recent studies have shown that ADTKD-UMOD is a relatively common cause of chronic kidney disease (CKD). However, the status of ADTKD-UMOD in Taiwan remains unknown. In this study, we identified three heterozygous UMOD missense variants, c.121T > C (p.Cys41Arg), c.179G > A (p.Gly60Asp), and c.817G > T (p.Val273Phe), in a total of 221 selected CKD families (1.36%). Two of these missense variants, p.Cys41Arg and p.Gly60Asp, have not been reported previously. In vitro studies showed that both uromodulin variants have defects in cell membrane trafficking and excretion to the culture medium. The structure model predicted altered disulfide bond formation in both variants, but only p.Gly60Asp was predicted to cause protein destabilization. Our findings extend the mutation spectrum and indicate that the ADTKD-UMOD contributed to a small but significant cause of CKD in the Taiwanese population.

Case Report: Late-Onset Mitochondrial Disease Uncovered by Metformin Use in a Patient With Acute Verbal Auditory Agnosia

Introduction

Verbal auditory agnosia is rarely caused by mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. Lactate acidosis, which is the adverse effect of metformin, has proposed links to mitochondrial dysfunction and may trigger clinical features of mitochondrial diseases.

Case Presentation

A 43-year-old right-handed man presented to our emergency department with acute onset fever and headache accompanied by impaired hearing comprehension. He could communicate well through handwritten notes but could not understand what others were saying. He had been diagnosed as having diabetes mellitus 2 months prior to this event. Vildagliptin 100 mg/day and metformin 1,700 mg/day were prescribed for glucose control. Laboratory tests revealed elevated lactate levels in serum and cerebrospinal fluid of the patient. Brain MRI disclosed bilateral temporal lesions. Acute encephalitis with temporal involved was initially diagnosed and acyclovir was given empirically. However, follow-up MRI after acyclovir treatment revealed a progression of prior lesions. Further mitochondrial genome analysis revealed a mitochondrial DNA point mutation at position 3,243 (m.3243A > G) with 25% heteroplasmy, which is compatible with MELAS. His clinical symptoms and serum lactate levels were improved after discontinuing the metformin use.

Conclusions

To our knowledge, this is the first report of a patient having late-onset MELAS syndrome that manifested as acute verbal auditory agnosia, which was identified after the patient began using metformin. Metformin is known to inhibit mitochondrial function and could trigger clinical features of MELAS syndrome. We encourage clinicians to maintain a high level of awareness that diabetes mellitus can be caused by mitochondrial disease and to exercise caution in the prescription of metformin.

Posterior reversible encephalopathy syndrome (PRES) in a patient with moyamoya disease: A case report

INTRODUCTION

Moyamoya disease (MMD) and posterior reversible encephalopathy syndrome (PRES) share similar pathophysiological characteristics of endothelial dysfunction and impaired cerebral autoregulation. However, there have never been any published studies to demonstrate the relationship between these 2 rare diseases.

PATIENT CONCERNS

A 26-year-old Asian man presented with a throbbing headache, blurred vision, and extremely high blood pressure. We initially suspected acute cerebral infarction based on the cerebral computed tomography, underlying MMD, and prior ischemic stroke. However, the neurological symptoms deteriorated progressively.

DIAGNOSIS

Cerebral magnetic resonance imaging indicated the presence of vasogenic edema rather than cerebral infarction.

INTERVENTIONS AND OUTCOMES

An appropriate blood pressure management prevents the patient from disastrous outcomes successfully. Cerebral magnetic resonance imaging at 2 months post treatment disclosed the complete resolution of cerebral edema. The patient's recovery from clinical symptoms and the neuroimaging changes supported the PRES diagnosis.

CONCLUSION

This report suggests that patients with MMD may be susceptible to PRES. It highlights the importance of considering PRES as a differential diagnosis while providing care to MMD patients with concurrent acute neurological symptoms and a prompt intervention contributes to a favorable clinical prognosis.

Vertebral artery aneurysms and the risk of cord infarction following spinal artery coverage during flow diversion

OBJECTIVE

Coverage of the anterior spinal artery (ASA) ostia is a source of considerable consternation regarding flow diversion (FD) in vertebral artery (VA) aneurysms due to cord supply. The authors sought to assess the association between coverage of the ASA, posterior spinal artery (PSA), or lateral spinal artery (LSA) ostia when placing flow diverters in distal VAs and clinical outcomes, with emphasis on cord infarction.

METHODS

A multicenter retrospective study of 7 institutions in which VA aneurysms were treated with FD between 2011 and 2019 was performed. The authors evaluated the risk of ASA and PSA/LSA occlusion, associated thromboembolic complication, complications overall, aneurysm occlusion status, and functional outcome.

RESULTS

Sixty patients with 63 VA and posterior inferior cerebellar artery aneurysms treated with FD were identified. The median aneurysm diameter was 7 mm and fusiform type was the commonest morphology (42.9%). During a procedure, 1 (61.7%) or 2 (33.3%) flow diverters were placed. Complete occlusion was achieved in 71.9%. Symptomatic thromboembolic complications occurred in 7.4% of cases and intracranial hemorrhage in 10.0% of cases. The ASA and PSA/LSA were identified in 51 (80.9%) and 35 (55.6%) complications and covered by the flow diverter in 29 (56.9%) and 13 (37.1%) of the procedures, respectively. Patency after flow diverter coverage on last follow-up was 89.2% for ASA and 100% for PSA/LSA, not significantly different between covered and noncovered groups (p = 0.5 and p > 0.99, respectively). No complications arose from coverage.

CONCLUSIONS

FD aneurysm treatment in the posterior circulation with coverage of ASA or PSA/LSA was not associated with higher rates of occlusion of these branches or any instances of cord infarction.

Overview of endovascular thrombectomy accessibility gap for acute ischemic stroke in Asia: A multi-national survey

Endovascular thrombectomy revolutionized the treatment of acute ischemic stroke. Nevertheless, access to endovascular thrombectomy is limited in many parts of the world. Asia holds 60% of the world’s population and its countries carry some of the highest stroke disease burden. To understand the availability of endovascular thrombectomy and intravenous thrombolysis in this region, we interviewed stroke neurologists and neuro-interventionists of 19 Asian countries, and found a large disparity in access to endovascular thrombectomy and intravenous thrombolysis between high- and low-income countries. Lack of neuro-interventionists, comprehensive stroke units, stroke triage systems and high treatment cost are the major obstacles to wider accessibility of endovascular thrombectomy, especially among developing countries. The potential solutions to provide equitable access to stroke revascularization therapy are discussed.

Endovascular Thrombectomy for Distal Occlusion Using a Semi-Deployed Stentriever: Report of 2 Cases and Technical Note

Distal intracranial occlusions can sometimes cause significant neurological deficits. Endovascular thrombectomy in these vessels may improve outcome but carry a higher risk of haemorrhagic complications due to the small calibre and tortuosity of the target vessel. We report two cases of isolated M2/3 artery occlusion causing dense hemiplegia that was successfully treated with stent retrieval thrombectomy. A “semi-deployment technique” of a 3 mm stentriever was employed at the M2/3 bifurcation of the middle cerebral artery. Partial stent unsheathing allowed adequate clot engagement while avoiding excessive tension by the stent metal struts along the tortuous course of a distal vessel. Complete revascularization was achieved after first-pass of the stent retriever without complication, resulting in good clinical outcome in both cases. The described semi-deployment technique reduces the radial and tractional force exerted by the stentreiver on small branches, and may reduce the risk of vessel laceration or dissection in distal vessel thrombectomy.

Endovascular treatment of debilitating tinnitus secondary to cerebral venous sinus abnormalities: a literature review and technical illustration

Background and objective

Pulsatile tinnitus (PT) can be debilitating and lead to significant morbidity. Cerebral venous sinus lesions, such as venous sinus stenosis, diverticula, and high-riding jugular bulb, are uncommon causes of PT, for which there is no standard treatment. Endovascular interventions have shown promising results for PT secondary to idiopathic intracranial hypertension, and may be a valid therapeutic option for isolated venous PT.

Methods

We conducted a systematic literature review on the outcome and safety of endovascular treatment for patients with isolated, debilitating venous PT. The venous lesion characteristics, endovascular techniques, complications, and clinical outcomes were assessed. In addition, an illustrative case of endovascular stenting for PT caused by venous sinus stenosis was included.

Results

A total of 41 patients (90.2% female) from 26 papers were included. The median age was 46 years (IQR 23; range 25–72 years). Focal venous sinus stenosis (20 patients) and sinus diverticula (14 patients) were the most common culprit lesions. Endovascular treatment included venous sinus stenting in 35 patients, 11 of whom had adjuvant coil embolization, and coil embolization alone in six patients. Complete resolution of the tinnitus was achieved in 95.1% of patients. There was one complication of cerebellar infarct, and no procedure-related mortality.

Conclusions

In patients with debilitating PT secondary to venous sinus lesions, endovascular treatment by stenting and/or coil embolization appears to be safe and effective. Prospective randomized studies with objective outcome assessments are needed to confirm the treatment benefits.

White matter damage and systemic inflammation in Parkinson's disease

Background

Systemic inflammation and white matter (WM) alterations have been noted as effects of Parkinson’s disease (PD). This study sought to evaluate WM integrity in PD patients using diffusion tensor imaging (DTI) and to assess its relationship with systemic inflammation.

Methods

Sixty-six patients with PD (23 men and 43 women) and 67 healthy volunteers (29 men and 38 women) underwent blood sampling to quantify inflammatory markers and DTI scans to determine fiber integrity. The inflammatory markers included leukocyte apoptosis, as well as cellular and serum adhesion molecules, in each peripheral blood sample. DTI-related indices [including fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD)] were derived from DTI scans. The resulting FA maps were compared using voxel-based statistics to determine differences between the PD and control groups. The differences in the DTI indices, clinical severity, and inflammatory markers were correlated.

Results

Exploratory group-wise comparison between the two groups revealed that the PD patients exhibited extensive DTI index differences. Low FA accompanied by high RD and MD, without significant differences in AD, suggesting a demyelination process, were found in the parietal, occipital, cerebellar, and insular WM of the PD patients. The declined DTI indices were significantly correlated with increased clinical disease severity, adhesion molecules, and leukocyte apoptosis.

Conclusions

Patients with PD experience WM integrity damage in vulnerable regions, and these impairments are associated with increased disease severity and systemic inflammation. The possible interactions among them may represent variant neuronal injuries and their consequent processes in PD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12868-017-0367-y) contains supplementary material, which is available to authorized users.

Associations among Cognitive Functions, Plasma DNA, and White Matter Integrity in Patients with Early-Onset Parkinson's Disease

Early-onset Parkinson's disease (EOPD) patients are symptomatic at a relatively young age, and the impacts of the disease on both the patients and their caregivers are dramatic. Few studies have reported on the cognitive impairments seen in EOPD, and the results of these studies have been diverse. Furthermore, it is still unclear what microstructural white matter (WM) changes are present in EOPD patients. As such, we conducted this study to investigate the microstructural WM changes experienced by EOPD patients and their association with cognitive function and plasma DNA levels. We enrolled 24 EOPD patients and 33 sex- and age-matched healthy volunteers who underwent complete neuro-psychological testing (NPT) to evaluate their cognitive function and diffusion tensor imaging (DTI) scanning to determine their fiber integrity. The plasma DNA measurements included measurements of nuclear and mitochondrial DNA levels. Fractional anisotropy (FA) maps were compared using voxel-based statistics to determine differences between the two groups. The differences in DTI indices and NPT scores were correlated after adjusting for age, sex, and education. Our results demonstrate that patients with EOPD have elevated nuclear DNA levels and wide spectrums of impairments in NPT, especially in the executive function and visuospatial function domains. Exploratory group-wise comparisons of the DTI indices revealed that the patients with EOPD exhibited lower DTI parameters in several brain locations. These poorer DTI parameters were associated with worse cognitive performances and elevated plasma nuclear DNA levels, especially in the anterior thalamic radiation region. Our findings suggest that the thalamus and its adjacent anterior thalamic radiation may be important in the pathogenesis of EOPD, as they appear to become involved in the disease process at an early stage.

Association Between Autonomic Impairment and Structural Deficit in Parkinson Disease

Patients with Parkinson disease (PD) have impaired autonomic function and altered brain structure. This study aimed to evaluate the relationship of gray matter volume (GMV) determined by voxel-based morphometry (VBM) to autonomic impairment in patients with PD. Whole-brain VBM analysis was performed on 3-dimensional T1-weighted images in 23 patients with PD and 15 sex- and age-matched healthy volunteers. The relationship of cardiovascular autonomic function (determined by survey) to baroreflex sensitivity (BRS) (determined from changes in heart rate and blood pressure during the early phase II of the Valsalva maneuver) was tested using least-squares regression analysis. The differences in GMV, autonomic parameters, and clinical data were correlated after adjusting for age and sex. Compared with controls, patients with PD had low BRS, suggesting worse cardiovascular autonomic function, and smaller GMV in several brain locations, including the right amygdala, left hippocampal formation, bilateral insular cortex, bilateral caudate nucleus, bilateral cerebellum, right fusiform, and left middle frontal gyri. The decreased GMVs of the selected brain regions were also associated with increased presence of epithelial progenitor cells (EPCs) in the circulation. In patients with PD, decrease in cardiovascular autonomic function and increase in circulating EPC level are associated with smaller GMV in several areas of the brain. Because of its possible role in the modulation of the circulatory EPC pool and baroreflex control, the left hippocampal formation may be a bio-target for disease-modifying therapy and treatment monitoring in PD.

A controllable double-well magneto-optical trap for Rb and Cs atoms

We experimentally demonstrate a novel scheme to simultaneously confine two atomic species of (87)Rb and (133)Cs with adjustable spatial separation by a controllable double-well magneto-optic trap. Using a single-loop wire and a magnetic bias field, the two clouds, each containing more than 1 x 10(6) atoms, are spatially separated above and below the wire center of the double-well MOT. The cloud interdistance can be controlled by independently varying the wire current and external bias field. This allows to load the double-well magnetic trap, and to study the dynamics of cold collisions between two-species atoms.

Effects of mixed chimerism and immune modulation on GVHD, disease recurrence and survival after HLA-identical marrow transplantation for hematologic malignancies

BACKGROUND

The success of allogeneic bone marrow transplantation(allo-BMT) is affected by underlying disease relapse. Although mixed chimerism(MC) is not necessarily a poor prognostic factor, several groups have suggested that MC is associated with an increased risk of disease relapse. There is evidence that patients with MC benefit from additional immunotherapy if the treatment is started in minimal residual disease status(mixed chimerism status), not in frank hematological relapse. The purposes of this study are to evaluate 1) the risk for relapse or graft rejection in correlation to persistent MC status after allo-BMT, and 2) the possibility of preventing relapse by immune modulation treatments (withdrawal or rapid taper-off of post-transplant immuno-suppression, additional interferon treatment, or the administration of donor lymphocytes) in hematologic malignancies.

PATIENTS AND METHODS

Of 337 allogeneic donor-recipient pairs between March 1996 and August 1998, 12 patients who showed persistent or progressive MC and who received immune modulation treatments were evaluated. Twelve patients, median age 31 years(range 9 to 39 years), received an allo-BMT for: acute myelogenous leukemia(AML, n = 5), chronic myelogenous leukemia(CML, n = 4), acute lymphocytic leukemia(ALL, n = 3). Serial polymerase chain reaction(PCR) analysis of YNZ 22-, 33.6-minisatellites or Y chromosome-specific PCR analysis at short term intervals(pre- and post-transplant 1, 3, 6, 9, ... months) was performed. Once MC was detected, immune modulation treatments on the basis of increasing MC in an early phase of recurrence of underlying disease were started.

RESULTS

Nine of 12 patients converted to complete chimerism(CC) (AML 5/5, CML 3/4, ALL 1/3). Four of 9 CC patients developed graft-versus-host disease(GVHD) grade < or = 2 during immune modulation. All were treated successfully with steroids. Three patients who were not converted to CC showed relapse of underlying diseases or graft failure.

CONCLUSION

The results demonstrate that, in patients with hematologic malignancies after allo-BMT, persistent MC is associated with relapse of underlying diseases or graft failure. Furthermore, when patients receive early immune modulation treatment, MC can be changed to complete donor pattern chimerism and ultimately prevent relapse.

Fabrication of submicron titanium-alloy particles for biological response studies

Biologic response to generated wear particles and subsequent aseptic loosening is a critical factor limiting the long-term survival of total hip replacements. To better understand the sequence of events leading to aseptic loosening and the role of the individual material components, fabricating metal particles similar to those present clinically is very important. We describe a simple milling technique to generate significant amounts of fine titanium-alloy (TiAlV) debris. A TiAlV rod was milled against a TiAlV plate in distilled water supplemented with antibiotics. The resulting debris were sedimented in alcohol and the fine debris were separated. Scanning electron microscopy analysis and particle size analysis demonstrated that the mean size of particles was 1.1 +/- 0.9 microm (range 0.2-4.2 microm). Sixty-two percent were smaller than 1.0 microm, and 85% were smaller than 2.0 microm. The particles generated had varying shapes, including angular or shard-like shapes with jagged and irregular outlines.

Failure of total hip arthroplasty with a precoated prosthesis. 4- to 11-year results

A series of early femoral component failures prompted a detailed retrospective clinical and radiographic review of 176 hybrid cemented total hip arthroplasties using a polymethyl-methacrylate coated femoral prosthesis. All surgeries were performed using third generation cement techniques. Average length of followup was 6.3 years (range, 3-12 years). Twenty-one patients died, and one underwent revision surgery because of sepsis. Of the remaining 154 total hip arthroplasties, 23 (15%) of the femoral components failed (21 revised, two definitely loose). The average time to revision was 3.9 years. None of the acetabular components failed. Comparison between the failure and nonfailure groups revealed that poor cement mantles (Grades C or D) with distal cement mantle deficiencies were statistically significant predictors of femoral failure. The most common mechanism of failure was progressive, circumferential cement-bone interface osteolysis with relative preservation of the cement-metal interface. Debonding of the cement column from the prosthesis was a late finding and occurred in only 45% of failed cases. Incorporating the techniques of centralization and centrifugation significantly improved clinical results. Strengthening of the cement-prosthesis interface may magnify the deleterious effects of a poor cement mantle and predisposes the cement-bone interface to failure.

Cross-reference weighted least square estimates for positron emission tomography

An efficient new method, termed as the cross-reference weighted least square estimate (WLSE) [CRWLSE], is proposed to integrate the incomplete local smoothness information to improve the reconstruction of positron emission tomography (PET) images in the presence of accidental coincidence events and attenuation. The algebraic reconstruction technique (ART) is applied to this new estimate and the convergence is proved. This numerical technique is based on row operations. The computational complexity is only linear in the sizes of pixels and detector tubes. Hence, it is efficient in storage and computation for a large and sparse system. Moreover, the easy incorporation of range limits and spatially variant penalty will not deprive the efficiency. All this makes the new method practically applicable. An automatically data-driven selection method for this new estimate based on the generalized cross validation is also studied. The Monte Carlo studies demonstrate the advantages of this new method.

A study of motor and sensory evoked potentials in chronic cauda equina compression of the dog

Previous experimental studies have shown the effects of acute compression of the spinal cord and peripheral nerve roots. Recently, however, a few studies of chronic compression of the cauda equina in animal models have been reported. The purpose of this study was to determine the long-term electrophysiologic changes resulting from chronic compression of the cauda equina in dogs. An animal model of lumbar spinal stenosis was prepared according to Delamarter's method. Four experimental groups, each containing six dogs, were studied. One group underwent only laminectomy of the sixth and seventh lumbar vertebrae; these animals served as controls. In the three other groups, a laminectomy was performed and the cauda equina was constricted by 25%, 50%, and 75%, respectively, to produce chronic compression. Weekly neurologic examinations were carried out, and the neurologic deficits were graded using a modified Tarlov system. Sensory, and motor evoked potentials were recorded preoperatively, immediately after constriction, and at 2 weeks and 1, 2, and 3 months postoperatively. The animals in the control group showed no changes in sensory or motor evoked potentials. The dogs in which the cauda equina had been constricted by 25% showed no neurologic deficits and only mild changes in sensory and motor evoked potentials. The dogs in which the cauda equina had been constricted by 50% showed mild initial motor weakness, and major changes in the evoked potentials. The dogs in which the cauda equina had been constricted by 75% showed significant weakness, paralysis of the tail, and urinary incontinence; all dogs were partially recovered by the 3rd month, but all still showed neurogenic changes in the evoked potentials. Sensory and motor evoked potentials revealed neurologic abnormalities before the appearance of neurologic signs and symptoms. Constriction of more than 50% was the critical point that resulted in complete loss or reduction of the evoked potentials and in neurologic deficits. Dogs in which motor and sensory evoked potentials recovered also showed gradual disappearance of neurologic symptoms and signs. Recovery of motor evoked potentials in particular was associated with complete disappearance of neurologic symptoms and signs. For accurate prognosis in cases of chronic cauda equina compression, a combined diagnostic study of sensory and motor evoked potentials is recommended.

Electrodiagnostic and histologic changes of graded caudal compression on cauda equina in dog

STUDY DESIGN

An animal model of lumbar spinal stenosis, in which the pathophysiology of this condition could be examined, was retrieved according to Delamarter's method.

OBJECTIVES

The purpose of this study was to develop a reproducible animal model of lumbar spinal stenosis to further understanding of the long-term electrophysiologic changes, and to detect prognostic indices of the long-term anatomic and physiologic status of chronic compression of the cauda equina.

SUMMARY OF BACKGROUND DATA

Somatosensory-evoked potentials and bulbocavernosus reflexes revealed abnormalities before neurologic signs and symptoms appeared. If delayed somatosensory-evoked potentials and bulbocavernosus reflexes were recovered with the lapse of time, neurologic findings showed gradual recovery. The loss of somatosensory-evoked potentials, bulbocavernosus reflexes, and neurologic, histological abnormalities occurred at 50% constriction of the cauda equina; at the same time, that was the critical point of possible recovery.

METHODS

Four experimental groups, each containing six dogs, were studied. One group had a laminectomy of the sixth and seventh lumbar vertebrae only; these animals served as controls. In the three other groups, a laminectomy was performed, and the cauda equina was constricted by 25%, 50%, or 75% to produce chronic compression according to Delamarter's method.

RESULTS

Somatosensory-evoked potentials and bulbocavernosus reflexes revealed neurologic abnormalities before the appearance of neurological signs and symptoms. Constriction of more than 50% was the critical point; it resulted in loss of evoked potentials, reflexes, neurologic deficits, and histological abnormalities.

CONCLUSION

To accurately forecast prognosis of chronic cauda equina compression, the combined diagnostic study of somatosensory-evoked potential with bulbocavernosus reflex is recommended.

The Orthofix external fixator for fractures of long bones

The Orthofix external fixator was used to treat 112 fractures of the long bones in 101 patients, and 22 patients with infected nonunions. Our results compared favourably with those reported in other series where external fixation was used. The overall rate of uncomplicated union was 69.6% with 24.1% of patients requiring a further operation. The overall incidence of nonunion (30.4%) was due to the relatively large number of severe open fractures in the series. The apparatus was simple to apply, and safe and effective in practice. We recommend its use for the primary treatment of open and segmental fractures, and for infected nonunion.

Effect of sodium hyaluronate on prevention of osteoarthritis

The changes in the surface of articular cartilage of femoral condyle from rabbits were evaluated after degenerative changes were made by the technique advocated by Hulth. The medial collateral and both cruciate ligaments were excised, and a medial menisectomy was done. Then the right knee joint was injected with 1 ml of Na-hyaluronate gel every two weeks. The animals were sacrificed at two, four, six, eight, or sixteen weeks postoperatively. After sacrifice, the medial femoral condyle was excised and prepared for the light microscopic and scanning electron microscopic study. At eight to sixteen weeks, there were chondrocyte clones with clefts to the radial zone and increased loss of the height of articular cartilage on the control side; but, on the experimental side there was a significant delay and lessening of the arthritic response. The biocompatibility and the protective effect of joint degeneration of this device make this material a valuable adjuvant in the treatment of osteoarthritis and the traumatized joints.

Deltoid sensory flap

Eight patients were treated using the deltoid sensory flap for soft-tissue injury of the extremities. The results were one-stage reconstructions of soft tissue extremity injuries. Protective sensibility was provided to the reconstructed area; there was no limitation of motion of the shoulder after the procedure; and primary closure of the donor site was feasible. The advantages of the deltoid sensory flap exceed those of other reconstructive procedures that are used in areas where sensibility is essential.

Clinical significance of the immunological tests in rheumatoid arthritis

Of the many theoretical causes of rheumatoid arthritis(RA), the most widely held theory is the autoimmune mechanism. In order to clarify the clinical significance of the immunological tests in RA, we studied immunoglobulin and complement levels in sera and synovial fluids of 118 RA patients and the following results were obtained. 1) The levels of immunoglobulins were elevated in both serum and synovial fluid and this was more prominent in the seropositive cases than the seronegative ones. 2) The levels of C3 component were decreased in both serum and synovial fluid, while those of C4 were decreased only in synovial fluid. Serum C3 and C4 component levels were more decreased in the seropositive cases than the seronegative ones. 3) The immunoglobulin levels in serum (IgG, IgM and IgA) and synovial fluid (IgG and IgA) and the levels of C3, C4 component in serum were well correlated with the clinical forms of rheumatoid arthritis. 4) The IgA level in serum and IgM level in synovial fluid were more increased in the exacerbated cases than the chronic ones. 5) Serum IgG level was decreased after steroid medication over one month.

Molecular analysis of membrane immunoglobulin-negative variants

The mouse B-cell lymphoma WEHI 279.1 is a tumor which synthesizes both membrane and secreted immunoglobulin M (IgM). We have immunoselected variants which fail to express the membrane form (mIgM-); the most frequently isolated phenotype is a complete loss of both membrane expression and synthesis of the mu heavy chain within the cells. We have chosen four of these mIgM- mutants for detailed molecular investigation. One of these has suffered a large deletion which covers the region of chromosome 12 containing the expressed mu gene, but three have no detectable changes in the DNA arrangement of the mu gene. All of the mutants, including the deletion mutant, synthesize 10-30% of the wild-type level of cytoplasmic mu RNA; however, none is the appropriate size for membrane mu (mu m) or secreted mu (mu s) message. Based on our studies of the deletion mutant, which retains its nonproductively arranged allele, at least some of these RNAs may be 'sterile' transcripts from the nonproductively arranged allele. However, if all of these mRNAs derive from the other allele, they represent a substantial elevation of these sterile messages relative to the wild-type level. Furthermore, the three nondeletion mutants transcribe mu RNA at a level indistinguishable from the wild type. It is likely that their defects lie in the stability, processing, or transport of the mu RNA within the nucleus. Somatic cell hybrids between P3X and the IgM- variants produced mostly mIgM- hybrids. However, a few mIgM+ hybrids were produced, suggesting that the mu- defects may be partly complemented by the P3X fusion partner.

Structure of acid protease from Endothia parasitica in cross-linked form at 2.45-A resolution

The structure of acid protease from Endothia parasitica in strongly cross-linked form is compared with that of the untreated protein at 2.45-a resolution. The only observed conformation change introduced by the cross-linking reaction is at the N terminal. Otherwise the two main chain structures are essentially identical. Approximately 2 molecules of the inhibitor, 1,2-epoxy-3-(p-nitrophenoxy)propane, are found to be incorporated into each protein molecule. They are covalently bound to the two aspartic residues at the active center.