Effects of glucose deprivation on the contractile response of the rabbit bladder to repetitive stimulation

The urinary bladder requires an adequate energy supply to maintain contractile function. The primary metabolic fuel is glucose. Through glycolysis and oxidative phosphorylation, high energy phosphates are generated, which in turn supply the metabolic energy for the contractile activities of the urinary bladder. The aim of this study was to determine the effects of glucose deprivation and recovery from glucose deprivation on the phasic and tonic components of the contractile responses of rabbit bladder strips to field stimulation, bethanechol, and KCI. The results can be summarized as follow: In response to glucose deprivation, (1) the tonic responses to field stimulation, bethanechol, and KCI all decreased at a significantly greater rate than the phasic responses; (2) the phasic and tonic responses to field stimulation were both reduced to less than 10% of control within 70 minutes of initiating glucose deprivation; (3) the tonic responses to bethanechol and KCI were reduced to approximately 10% of control within 180 minutes whereas the phasic responses remained stable at 40 and 30%, respectively; and (4) glucose replacement stimulated a rapid and nearly complete recovery of the phasic and tonic components of the responses to field stimulation, bethanechol, and KCI. These results indicate that the tonic responses to all forms of stimulation are more sensitive to glucose deprivation than the phasic responses. © 1996 Wiley-Liss, Inc.     

The cavernoso-anal reflex： response of the anal sphincters to cavernosus muscles＇ stimulation

Aim： To prove the hypothesis that cavernosus muscles＇ contraction during coitus affects the reflex contraction of anal sphincters. Methods： Electromyographic response of external and internal anal sphincters to ischiocavernosus and bulbocavernosus muscle stimulation was studied in 17 healthy volunteers （10 men, 7 women, mean aged 38.3 ± 11.6 years）. The test was repeated after individual anesthetization of anal sphincters and the two cavernosus muscles,and after using saline instead of lidocaine. Results： Upon stimulation of each of the two cavernosus muscles,external and internal anal sphincters recorded increased electromyographic activity. Anal sphincters did not respond to stimulation of the anesthetized cavernosus muscles nor did anesthetized anal sphincters respond to cavernosus muscles＇ stimulation. Saline infiltration did not affect anal sphincteric response to cavernosal muscles＇ stimulation.Conclusion： Cavernosus muscles＇ contraction is suggested to evoke anal sphincteric contraction, which seems to be a reflex and mediated through the ＂cavernoso-anal reflex＂. Anal sphincteric contraction during coitus presumably acts to close the anal canal to thwart flatus or fecal leak.     

Division of autonomic nerves within the neurovascular bundles distally into corpora cavernosa and corpus spongiosum components: immunohistochemical confirmation with three-dimensional reconstruction

Background

Detailed knowledge of the distribution and distal course of periprostatic nerves is essential to improve functional outcomes (erection and continence) after radical prostatectomy (RP).

Objective

To describe the location of nerve fibres within neurovascular bundles (NVBs) and around the prostate by three-dimensional (3D) computer-assisted anatomic dissection (CAAD) in human foetuses and adult cadavers.

Design, setting, and participants

Serial transverse sections of the pelvic portion were performed in seven human male foetuses and four male adult cadavers. Sections were treated by histologic coloration and neuronal immunolabelling of S100 protein. 3D pelvic reconstruction was achieved with digitised serial sections and WinSurf software.

Measurements

We evaluated the distribution of nerve fibres within the NVB qualitatively. The distribution of periprostatic nerves was also evaluated quantitatively in the adult specimens.

Results and limitations

Periprostatic nerve fibres were dispersed around the prostate on all sides with a significant percentage of these fibres present in the anterior and anterolateral sectors. At the prostate apex and the urethral levels, the NVBs have two divisions: cavernous nerves (CNs) and corpus spongiosum nerves (CSNs). The CNs were a continuation of the anterior and anterolateral fibres around the apex of the prostate, travelling towards the corpora cavernosa. The CSNs were a continuation of the posterolateral NVBs, and they eventually reached the corpus spongiosum. The limitations of this study were the small number of specimens available and the lack of functional information.

Conclusions

The anterolateral position of CNs at the apex of the prostate and the autonomic innervation towards the corpus spongiosum via CSNs indicate possible ways to minimise the effect of prostate surgery on sexual function. The ideal dissection plane should probably include the preservation of the anterolateral tissues and fascias to avoid CN lesions. Anatomic knowledge gained from CAAD pertains directly to proper surgical technique and subsequent recovery of erectile function after RP.     

Inhibitory effect of serotonergic drugs on contractile response of the rat vas deferens to electrical nerve stimulation: in vivo study

PURPOSE: To evaluate, in vivo, the inhibitory effects of certain serotonergic drugs on the contractile response of the rat seminal tract to electrical stimulation of the hypogastric nerve. MATERIALS AND METHODS: Twenty-five Sprague Dawley rats (250 to 300 gm. each) were equally divided into 5 groups based on experimental agent; normal saline, clomipramine, sertraline, paroxetine, and fluoxetine. The hypogastric nerve was electrically stimulated and the intraluminal pressure of the vas deferens was measured, both pretreatment and 30 minutes after intravenous injection of four different doses (0.1 to 20 x the therapeutic dose) of each agent. Variations of responses relative to the time after administration of each agent (at 10- and 20-fold concentration) were also observed. RESULTS: All serotonergic drugs caused dose-dependent inhibition of elevation in intraluminal pressure of the vas deferens (p <0.05). The inhibitory effect of clomipramine was significantly better (p <0. 05) than that of fluoxetine at a 1-fold dose, while no significant differences were noted among clomipramine, sertraline and paroxetine. At doses of 10- and 20-fold, clomipramine had the strongest inhibitory effect, followed by sertraline and paroxetine, then fluoxetine (p <0.05). No differences were found in the inhibitory effects of the drugs studied, as a function of the time after injection. CONCLUSIONS: Clomipramine was the most potent drug for inhibition of elevation in intraluminal pressure of the rat vas deferens induced by electrical stimulation of the rat hypogastric nerve. The stronger inhibitory effect of clomipramine than the selective serotonin reuptake blockers suggests a possible peripheral action of clomipramine in addition to its central serotonergic action.     

The effects of androgen on penile reflex, erectile response to electrical stimulation and penile NOS activity in the rat

Aim: To investigate the effects of androgen on penile erection through the reflex arc and penile corpus cavernosum,and study the respective roles of testosterone (T) and dihydrotestosterone (DHT) in penile erection ira rats. Methods:Male Sprague-Dawley rats were castrated and implanted with silastic brand silicone tube containing T or DHT, with orwithout daily injections of a 5a-reductase inhibitor, MKM-434. The penile reflex, erectile response to electrical stimula-tion (ES) of the cavernous nerves and penile nitric-oxide synthase (NOS) activity were observed under varying andro-genic status. Results: Penile reflex erection in the rat was, on the whole, related to serum T levels though the numberof glans engorgernents was not. The number of cups and flips was significantly decreased by castration, and restoredto the control level by T supplementation. Erectile response to ES and NOS activity in penile tissue was also related toserum T level. T administered together with a ,5a-reductase inhibitor no longer restored the number of reflex erection,erectile responses to ES and NOS activity in the corpus cavemosum. Conclusion: Androgen influenced the penile re-flex arc, corpus cavemosum, and the perinea] striated muscles, ha reflex erection, erectile response to ES and penileNOS activity in the rat, T seeras to be first conyerted to DHT, the more active androgen modality. (Asian JAndrol1999Dec; 1: 169-174)     

A functional study of purinergic signalling in the normal and pathological rabbit corpus cavernosum

OBJECTIVE

To examine rabbit cavernosal smooth muscle (CSM) relaxation to ATP, ADP and UTP in normal rabbits and in models of conditions that predispose to erectile dysfunction (ED), diabetes mellitus (DM; induced for 6 months) and bladder outlet obstruction (BOO, 6 weeks after surgery).

MATERIALS AND METHODS

Concentration‐response curves (CRCs) were constructed to ATP, ADP and UTP on CSM from control rabbits in the absence and presence of antagonists. In addition, CRCs were constructed to ATP in CSM from rabbits with DM and BOO.

RESULTS

ATP and UTP caused equipotent, dose‐dependent relaxations of pre‐contracted normal rabbit CSM; ADP was more potent. Relaxation was inhibited by Reactive Blue 2, but not by suramin, 8‐p‐sulfophenyltheophylline or L‐N^G‐nitroarginine methyl ester. In rabbits with DM and those with partial BOO, ATP‐mediated CSM relaxation was less than in control rabbits. Pharmacological profiling suggests that purine‐induced CSM relaxation might be mediated by P2Y₁ and P2Y₄ receptors in the rabbit.

CONCLUSIONS

In healthy rabbits, ATP released from nerves appears to produce relaxation of CSM via P2Y₄ receptors on smooth muscle, while ADP, acting on P2Y₁ receptors on endothelial cells, produces relaxation via nitric oxide. Alterations in CSM purinergic signalling might be implicated in the pathophysiology of ED associated with DM and BOO. Characterization of purinergic signalling in CSM might highlight new therapeutic targets for treating ED.     

In vivo and in vitro response of corpus cavernosum to phosphodiesterase-5 inhibition in the hypercholesterolaemic rabbit

OBJECTIVE

To investigate the effects of hypercholesterolaemia (HC) on rabbit corpus cavernosa in vivo and in vitro, and evaluate the efficacy of vardenafil and sildenafil in normal and HC rabbits, as the phosphodiesterase‐5 (PDE‐5) inhibitors vardenafil and sildenafil are widely used for treating erectile dysfunction (ED) and most organic causes of ED are associated with vascular risk factors like HC.

MATERIALS AND METHODS

Male New Zealand White rabbits were randomly divided into two groups; 11 HC rabbits were fed a 2% cholesterol diet, and 12 age‐matched control rabbits received a regular diet. After 12–14 weeks, erectile responses to intravenous sodium nitroprusside (SNP) and PDE‐5 inhibitors were evaluated for 2 h in conscious rabbits. Penile length was measured and the area under the curve calculated. Relaxant responses of corpus cavernosal strips to electrical‐field stimulation (EFS) were measured before and after exposure to PDE‐5 inhibitors and the nitric oxide synthase inhibitor N′‐nitro‐ l ‐arginine methyl ester.

RESULTS

HC rabbits had a lower erectile response to SNP than controls; in both control and HC rabbits there was a greater erectile response after simultaneous exposure to SNP and vardenafil, or SNP and sildenafil. However, the responses of the HC rabbits were still significantly less than those of the controls. Corpora from control rabbits responded to EFS with greater relaxations at all frequencies, except 1 Hz. Corpora from both HC and control rabbits had greater responses to EFS after exposure to vardenafil and sildenafil; N′‐nitro‐ l ‐arginine methyl ester diminished the response to EFS.

CONCLUSIONS

There was a significantly lower in vivo and in vitro erectile response in HC rabbits than in controls; erectile function measured in conscious rabbits can be used to assess quantitatively the efficacy of different agents, e.g. sildenafil and vardenafil, in pathological animals. In addition, both agents improve in vitro responses of erectile tissue from HC rabbits to EFS.

     

Rheumatoid factor and response to TNF antagonists in rheumatoid arthritis: Systematic review and meta-analysis of observational studies

ObjectiveTo systematically analyze literature with the aim of examining whether rheumatoid factor (RF) is a predictor of response to tumor necrosis factor (TNF) antagonists in rheumatoid arthritis (RA).MethodsA systematic review and meta-analysis of observational studies were conducted. All studies on the association of baseline RF (titer and/or status) and response to any TNF antagonists, or with enough information to estimate this association were included. Qualitative analysis and meta-analysis using random-effects approach by type of outcome response and RF test was performed. Risk of publication bias was also evaluated.ResultsThe systematic review included 18 studies of 4163 identified articles, involving 5703 patients with homogeneous baseline characteristics. The most common outcome to assess response was European League Against Rheumatism (EULAR) response criteria, normally merging good and moderate categories as response. The weighted mean difference (WMD) of baseline IgM RF titer in meta-analysis was higher in the non-responders group [−101.58 (95% CI −156.58,−46.59) I² = 0.0]. Combined odds ratios (ORs) of positive IgM RF, positive IgA RF, and positive IgG RF to achieve good/moderate response were 1.08 (0.80, 1.47), I² = 40.9%; 0.83 (0.39, 1.73), I² = 39.8%, and 1.30 (0.48, 3.51), I² = 62.9%, respectively. We did not find an association between a positive IgM RF and EULAR good response or remission.ConclusionsThis meta-analysis does not support baseline IgM RF titer as a predictor of response to TNF antagonists in RA. However, this conclusion is hampered by high heterogeneity in the studies included in this meta-analysis.     

Online signal processing of internal anal sphincter activity during pelvic autonomic nerve stimulation: a new method to improve the reliability of intra‐operative neuromonitoring signals

Aim Intra‐operative neuromonitoring is increasingly applied in several surgical disciplines and has been introduced to facilitate pelvic autonomic nerve preservation. Nevertheless, it has been considered a questionable tool for the minimization of risk, as the results are variable and might be misleading. The aim of the present experimental study was to develop an intra‐operative neuromonitoring system with improved reliability for monitoring pelvic autonomic nerve function. Method Fifteen pigs underwent low anterior rectal resection with pelvic autonomic nerve preservation. Intra‐operative neuromonitoring was performed under autonomic nerve stimulation with observation of electromyographic signals of the internal anal sphincter and bladder manometry. As the internal anal sphincter frequency spectrum during stimulation was found to be mainly in the range of 5–20 Hz, intra‐operative neuromonitoring signals were postoperatively processed by implementation of matching band pass filters. Results In 10 preliminary experiments, signal processing was performed offline in the postoperative analysis. Of 163 stimulations intra‐operatively assessed by the surgeon as positive responses, 135 (83%) were confirmed after signal processing. In the following five consecutive experiments intra‐operative online signal processing was realized and demonstrated reliable intra‐operative neuromonitoring signals of internal anal sphincter activity with significant increase during pelvic autonomic nerve stimulation [0.5 μV (interquartile range = 0.3–0.7) vs 4.8 μV (interquartile range = 2.5–7.5) ;P < 0.001]. Conclusion Online signal processing of internal anal sphincter activity aids reliable identification of pelvic autonomic nerves with potential for improvement of intra‐operative neuromonitoring in pelvic surgery.     

Cell culture of rabbit meniscal fibrochondrocytes: proliferative and synthetic response to growth factors and ascorbate

This study was undertaken to determine whether the cells of the fibrocartilaginous meniscal substance are capable of proliferation and matrix synthesis. Cells were isolated from the fibrocartilaginous menisci of young New Zealand white rabbits, and grown in two alternative culture regimens differing only in the basal nutrient medium used to initiate primary monolayer growth. Under each culture regimen, the cells attached and proliferated both initially and after passage into secondary (2 degrees) culture. Differences were noted in cell morphology and time to reach confluence in primary (1 degrees) culture. Upon passage into 2 degrees culture, the fibrochondrocytes assumed two distinct morphologies depending upon the type of medium used for 1 degree culture. These morphological changes were accompanied by differences in the population doubling time and incorporation of 35SO4 into sulfated proteoglycans. The proliferation of both fibrochondrocyte subtypes was stimulated by the addition of either pituitary fibroblast growth factor (FGF) or human platelet lysate in a dose-dependent manner. Both FGF (10 ng/ml) and ascorbate (40 micrograms/ml) decreased 35-sulfate incorporation, whereas only ascorbate was found to alter the amount of sulfated glycosaminoglycan in the pericellular coat. We conclude that the fibrochondrocytes of the meniscal substance are capable of replication and synthesis of matrix macromolecules if given the proper stimuli. Additionally, there may be two subpopulations of fibrochondrocytes that can be distinguished by their in vitro behavior.     

Microvascular response in the rabbit ear to total body cooling: A model for study of human digits

Conditions such as Raynaud's disease, cold intolerance following digit replantation, and reflex sympathetic dystrophy are all exacerbated by diminished blood flow in the digits. The rabbit ear, being similar to the human digit, is an excellent model for studying microvascular responses during thermoregulation and was used in this study of microcirculatory changes during total-body cold stress. In eight rabbits a window was placed in one ear each, and the underlying vascular beds were photographed with the unanesthetized animal at room temperature (23°C) and in a cold room (6°C). Luminal arterial diameters constricted more than venular diameters during cold stress (39.6% vs. 16.5%, respectively, of the control diameters; P = 0.014). All responses were linear; the slopes of the regression lines were significantly different between arterioles and venules (P < 0.0001). This study suggests that decreased circulation in response to cold is due to decreases in the diameter and number of vessels available for perfusion, as predicted by the Poiseuille equation. © 1994 Wiley-Liss, Inc.     

Barriers and facilitators to provide continuity of care to dischargeable patients in disasters: A qualitative study

ObjectiveEarly discharge of some in-patients is the effective measure to create hospital surge capacity in disasters. However, some of these patients may need to post-discharge continuity of care. The aim of the current study then is to explore the barriers of continuity of care, and to provide suitable solutions for potentially dischargeable patients during disasters.MethodsThis qualitative study was conducted in Iran in 2017. The data was collected via unstructured interviews with 24 disaster professionals; and analyzed by content analysis method.ResultsIdentified barriers to the continuity of care were classified into seven categories, ‘lack of disaster paradigm’; ‘challenges of pre-hospital system’; ‘insufficient coordination and cooperation’; ‘inadequate hospital preparedness’; ‘lack of using available resources and capacities’; ‘poor patients' knowledge’ and ‘poor planning’. The suggested solutions for post-discharge continuity of care were: creation of registry and follow-up system; removing pre-hospital challenges; including disaster management courses in medical school curriculum; promoting hospital preparedness by All-Hazard Approach; and effective use of available resources.ConclusionUnderstanding the barriers to continuity of care for discharged patients for adopting policies based on experiences of health care providers can help planners to design and implement effective programs, which will enhance patients' access to necessary care.     

血小板浓缩液的制备及促进兔尺骨骨折愈合方面的实验研究

目的：探索动脉血小板浓缩液，在无菌情况下的制备方法。通过免疫组化及物理测量，证实血小板浓缩液中含有多种生长因子，并对比分析其对骨折愈合不同时期的促进作用，为临床应用提供基础资料。方法：选用20只新西兰兔，随机分成2组，分别为空白组及血小板组。制作尺骨中段骨折动物模型，采用指钢板行内固定。在手术之前，先抽取兔股动脉血6ml左右，经枸橼酸钠抗凝后，加低速高速离心，提纯出白色的血小板浓缩液，将其注射回骨折断端。所有操作均为无菌操作。分别在1、2、4及6周处死兔，在骨折处取5mm骨组织标本。切片作PDGF免疫组化染色定性分析及测量骨痂直径定量分析。结果：①6ml的兔动脉血在低速及高速离心后，可分离出0．5ml的血小板浓缩液，浓度在正常兔血小板浓度的3倍以上。②免疫组化染色阳性产物呈棕黄色颗粒状。在空白组术后第1周及第2周PDGF因子为阴性表达，第4周、第6周为弱阳性表达；在血小板浓缩液组，随着处死时间延长，阳性表达率逐渐增高。在相同的处死时间，血小板浓缩液组阳性表达率明显高于空白组。空白组、血小板组兔尺骨骨折标本在1、2、4、6周，均有不同程度骨痂形成，其中以第6周兔骨痂最多，第1周兔以纤维连接为主，仅有少许骨痂形成。空白组与血小板组同期骨痂直径差异有显著性意义。结论：①少量的兔血在严格的实验条件下，能够制备出血小板浓缩液。②兔血小板浓缩液中确含有较高浓度的PDGF生长因子。③血小板浓缩液加速了骨折断端的愈合。     

The role of reflexes in modifying the response to bethanechol chloride: A basis for selectivity of action on the bladder

When bethanechol is administered subcutaneously it induces a reflex-dependent sustained bladder contraction, and causes significant salivation but has little effect on blood pressure or heart rate. This relative selectivity of action is important for the clinical utility of the drug. We tested the hypothesis that the absence of cardiovascular effects is due to reflex compensation by assessing bethanechol's actions after blocking these reflexes. In chloralose-anesthetized cats the bladder was cannulated for pressure recording. Bethanechol (0.055–0.20 mg/kg SC) caused a sustained bladder contraction with no significant change in heart rate. During hexamethonium infusion (2 mg/min IV) SC bethanechol caused a fall in heart rate with no bladder contraction. Thus, strong cardiac compensatory reflexes normally prevent bethanechol-induced bradycardia. The time course of bradycardia and bladder contraction in the same bethanechol injection were compared during blockade with the β₁-antagonist metoprolol (0.4 mg/kg IV). The nadir of the bradycardia did not coincide with the sustained bladder contraction. Furthermore, the time to peak bladder effect diminished with SC dose while the time to nadir of bradycardia did not. If the time course of the bradycardia reflects plasma bethanechol concentration, then triggering of the bladder reflex cannot be related directly to this level. The difference in latency may be related to distribution barriers or to response time differences.     

Human brain region response to distention or cold stimulation of the bladder: a positron emission tomography study

PURPOSE: Several kinds of perceptions, including distention and coldness, arise from the bladder. Information on bladder fullness conveyed by mechanoreceptors within the bladder wall contributes to the basic micturition reflex via the bulbospinal reflex pathway, whereas cold stimulation of the bladder is processed differently. To elucidate the human brain mechanisms of voluntary urine storage and bladder cold perception we performed positron emission tomography scanning to examine brain regions activated by bladder distention or cold stimulation. MATERIALS AND METHODS: A total of 17 right-handed healthy male volunteers were catheterized via the urethra for bladder infusion. Subjects were divided into 2 groups for 2 types of positron emission tomography, namely the bladder distention group-11 who were 24 to 41 years old and the intravesical ice water group-6 who were 24 to 38 years old. Data were analyzed by the statistical parametric mapping procedure. RESULTS: Significant brain activation during maximum urine storage (bladder distention) were found in the pons, midbrain periaqueductal gray, anterior insula, putamen, thalamus and anterior cingulate gyrus. On the other hand, intravesical ice water instillation significantly activated several regions in frontal and parietal lobes, amygdala-hippocampus area and crus cerebri ventral border. Distribution of the activated regions after intravesical instillation of ice water overlapped none of those observed after bladder distention. CONCLUSIONS: Our data show that the brainstem as well as more rostral regions are involved in voluntary urine storage and these regions are functionally separated from those associated with bladder cold perception in healthy individuals.     

How age impairs the response of the neuromuscular junction to nerve transection and repair: An experimental study in rats

Age is the most important predictor of clinical outcome after peripheral nerve injury. The stability of the neuromuscular junction (NMJ) after denervation is thought to be central to neuromuscular recovery. Stability is characterized by maintenance of the motor endplate and mRNA upregulation of the constituent nicotinic acetylcholinergic receptor (nAChR) subtypes and the muscle regulatory factors (MRFs). The purpose of this study was to determine the effect of age on the recovery and stability of the postsynaptic NMJ after peripheral nerve injury. Young and aged rats underwent transection and repair of the tibial nerve. At 1, 2, 4, 8, or 16 weeks following transection, the gastrocnemius was examined for electrical recovery, NMJ fragmentation and endplate area, mRNA, and protein levels of the MRFs and nAChR subtypes. After nerve injury, aged NMJ exhibited significant fragmentation and loss of motor endplate area while the young NMJ remained relatively stable. Concomitantly, age impaired peak upregulation of the MRFs and nAChRs. However, expression of γ‐nAChR and myogenin after nerve injury was not affected by age. These data support the claim that upregulation of the nAChRs and MRFs may play an important role in maintaining NMJ stability following nerve transection and repair. Furthermore, expression of γ‐nAChR and myogenin does not appear to prevent age‐related NMJ fragmentation and loss of endplate area after nerve injury. These impairments of the aged NMJ response to injury may contribute to the poor neuromuscular recovery seen after nerve injury in this population. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:385–393, 2009     

老年共病患者心理危机自我表露阻碍和促进因素的质性研究

目的 深入探究老年共病患者心理危机表露的阻碍和促进因素,为促进老年患者面临心理危机时的自我表露提供依据。方法 采用现象学研究方法,访谈14例老年共病患者。结果 阻碍因素包括个人因素(内向/隐忍型性格、担心给家人带来困扰、对生命状态的负性心理)和动机因素(消极反馈、认知缺乏、时间弱化),促进因素包括感知表露后益处、良好的支持系统、个人表达意愿强。结论 老年共病患者心理危机表露存在阻碍和促进因素,应通过让患者感知表露后益处、给予良好的支持系统、丰富多种表露途径、加强患者对心理危机的认知等措施来促进老年共病患者主动表露其心理危机。     

PRES secondary to autonomic dysreflexia: A case series and review of the literature

Context: Autonomic dysreflexia (AD) is a complex syndrome seen in patients with spinal cord injuries (SCI) and can be life-threatening with a significant negative impact on the health of the individual. Posterior reversible encephalopathy syndrome (PRES) is thought to be caused, in part, by rapid elevations in blood pressure; leading to posterior cerebral circulatory edema. This can result in seizures, blindness and can progress to fatal intracranial hemorrhages.Findings: Here we present two cases of patients with SCI who developed PRES from AD. Each patient was correctly diagnosed, leading to appropriate treatment of the factors leading to their AD and subsequent resolution of their PRES symptoms.Conclusions/Clinical Relevance: In SCI patients who present with new seizures, visual deficits, or other neurologic signs, PRES should be considered as a part of the differential diagnosis as a good outcome relies on rapid recognition and treatment of AD.     

A stochastic model of knee angle in response to electrical stimulation of the quadriceps and hamstrings muscles

A novel stochastic model of knee angle in response to stimulation of the quadriceps and hamstrings muscle groups is presented. This model includes uncertainty due to fatigue and day-to-day changes in the stimulated muscles. The model consists of a normally distributed random variable whose mean and standard deviation vary with time and is characterized using data from a complete spinal cord injuries subject. The experimental data show a significant difference between the left and right legs under certain conditions, and suggest that fatigue-related and day-to-day variation may also be important. The purpose of this model is to generate more realistic electrically stimulated knee movements. This stochastic modeling technique could be incorporated into a comprehensive model of a joint actuated with electrical stimulation, and has great potential as a tool for analyzing closed-loop performance of electrically stimulated systems.     

A histologic analysis of the effects of stainless steel and titanium implants adjacent to tendons: an experimental rabbit study

PURPOSE: The current trend is to treat distal radius fractures with open reduction and internal fixation with either titanium or stainless steel plates. Both provide stable fixation; however, there is minimal evidence concerning the soft-tissue response to these materials. Our objective was to evaluate the response of adjacent extensor tendons to titanium and stainless steel in a rabbit in vivo model and to evaluate the influence of time. METHODS: Forty rabbits were divided into 5 groups of 8 rabbits each. Groups I and II had unilateral osteotomy of the distal radius followed by dorsal fixation with titanium and stainless steel plates, respectively. Groups III and IV had fixation with titanium and stainless steel, respectively, but without osteotomy. Group V had surgical dissection without osteotomy or plates. Two animals per group were killed at 1, 4, 12, and 24 weeks. The specimens (distal radius, plate, overlying soft tissue, and extensor tendon) were harvested en bloc for histologic analysis. For interface preservation between implant and tissues the specimens were embedded in methylmethacrylate, sectioned, and stained with hematoxylin-eosin. RESULTS: Histologic analysis showed a fibrous tissue layer formed over both implants between the plate and the overlying extensor tendons in the groups treated with plating independently of the material and the presence or absence of osteotomy. This fibrous layer contained the majority of debris. Metallic particles were not observed in the tendon or muscle substance of any animals; however, they were visualized in the tenosynovium. Hematoxylin-eosin-stained sections of groups I through IV showed proliferative fibroblasts and metallic particles; however, this layer was not observed in group V. Statistical analysis did not show differences between the groups regarding the number of cells or metallic particles. CONCLUSIONS: Our results indicate that both implants generated adjacent reactive inflammatory tissue and particulate debris. There was no difference in cell or particle number produced by both materials. There is a statistically significant increase in inflammatory cells with increasing time of implantation.