Photothermal properties of shape memory polymer micro-actuators for treating stroke

BACKGROUND AND OBJECTIVES: In this paper the photothermal engineering issues of novel shape memory polymer (SMP) microactuators for treating stroke are presented. The engineering issues for using lasers to heat and subsequently actuate these SMP devices are presented in order to provide design criteria and guidelines for intravascular, laser activated SMP devices. MATERIALS AND METHODS: A total of three devices will be presented: two interventional ischemic stroke devices (coil and umbrella) and one device for releasing embolic coils (microgripper). The optical properties of SMP, methods for coupling laser light into SMP, heating distributions in the SMP devices, and the impact of operating the thermally activated material in a blood vessel are presented. RESULTS: Actuating the devices requires device temperatures in the range of 65-85 degrees C. Attaining these temperatures under flow conditions requires critical engineering of the SMP optical properties, optical coupling into the SMP, and device geometries. CONCLUSION: Laser-activated SMP devices are a unique combination of laser-tissue and biomaterial technologies. Successful deployment of the microactuator requires well-engineered coupling of the light from the diffusing fiber through the blood into the SMP.     

Postoperative Cognitive Dysfunction in Patients with Preoperative Cognitive Impairment: Which Domains Are Most Vulnerable?

Background: The authors explored the database of the first International Study of Postoperative Cognitive Dysfunction study to specify the domains of cognitive function that were most vulnerable and to determine the pattern of deterioration in patients with preoperative cognitive impairment.

Methods: One thousand two hundred eighteen patients were included in the first International Study of Postoperative Cognitive Dysfunction, where neuropsychological testing was performed at entry to the study, at 1 week, and at 3 months after surgery. The authors' analyses determined the extent to which seven neuropsychological measures changed after surgery with focus on the relation with preoperative cognitive impairment, defined as a preoperative score 1.5 SD below healthy controls in the memory test.

Results: Preoperative cognitive impairment was found in 74 patients at baseline. At 1 week, cognitive deterioration was seen in all tests, but in particular in the Letter Digit Coding and the time of the Stroop interference test, with 14% and 16% of the total sample (n = 1,016) exceeding 2 SD, respectively. At 3 months, deterioration was more uniform. Significantly fewer in the preoperative cognitive impairment group had deterioration in the memory test, both at 1 week and at 3 months, with no patient displaying a deterioration exceeding 2 SD.     

A reasonable mechanism for visible light-induced skin rejuvenation

In recent years, much research has been done in the field of non-ablative skin rejuvenation. This comes as a response to the continuous demand for a simple method of treating rhytides, UV exposure, and acne scars. Numerous researches involve visible light-pulsed systems (20–30 J/cm²). The mechanism of action is believed to be a selective heat-induced denaturalization of dermal collagen that leads to subsequent reactive synthesis (Bitter Jr., Dermatol. Surg., 26:836–843, 2000; Fitzpatrick et al., Arch. Dermatol., 132:395–402, 1996; Kauvar and Geronemus, Dermatol. Clin., 15:459–467, 1997; Negishi et al., Lasers Surg. Med., 30:298–305, 2002; Goldberg and Cutler, Lasers Surg. Med., 26:196–200, 2000; Hernandez-Perez and Ibeitt, Dermatol. Surg., 28:651–655, 2002). In this study, we suggest a different mechanism for photorejuvenation based on light-induced reactive oxygen species (ROS) formation. We irradiated collagen in vitro with a broadband of visible light (400–800 nm, 24–72 J/cm²) and used the spin trapping coupled with electron paramagnetic resonance spectroscopy to detect ROS. Irradiated collagen resulted in hydroxyl radicals formation. We propose, as a new concept, that visible light at the energy doses used for skin rejuvenation (20–30 J/cm²) produces high amounts of ROS, which destroy old collagen fibers, encouraging the formation of new ones. On the other hand, at inner depths of the skin, where the light intensity is much weaker, low amounts of ROS are formed, which are well known to stimulate fibroblast proliferation.     

Advancing paternal age and autism

CONTEXT: Maternal and paternal ages are associated with neurodevelopmental disorders. OBJECTIVE: To examine the relationship between advancing paternal age at birth of offspring and their risk of autism spectrum disorder (ASD). DESIGN: Historical population-based cohort study. SETTING: Identification of ASD cases from the Israeli draft board medical registry. PARTICIPANTS: We conducted a study of Jewish persons born in Israel during 6 consecutive years. Virtually all men and about three quarters of women in this cohort underwent draft board assessment at age 17 years. Paternal age at birth was obtained for most of the cohort; maternal age was obtained for a smaller subset. We used the smaller subset (n = 132 271) with data on both paternal and maternal age for the primary analysis and the larger subset (n = 318 506) with data on paternal but not maternal age for sensitivity analyses. MAIN OUTCOME MEASURES: Information on persons coded as having International Classification of Diseases, 10th Revision ASD was obtained from the registry. The registry identified 110 cases of ASD (incidence, 8.3 cases per 10 000 persons), mainly autism, in the smaller subset with complete parental age data. RESULTS: There was a significant monotonic association between advancing paternal age and risk of ASD. Offspring of men 40 years or older were 5.75 times (95% confidence interval, 2.65-12.46; P<.001) more likely to have ASD compared with offspring of men younger than 30 years, after controlling for year of birth, socioeconomic status, and maternal age. Advancing maternal age showed no association with ASD after adjusting for paternal age. Sensitivity analyses indicated that these findings were not the result of bias due to missing data on maternal age. CONCLUSIONS: Advanced paternal age was associated with increased risk of ASD. Possible biological mechanisms include de novo mutations associated with advancing age or alterations in genetic imprinting.     

Scleraxis expression is coordinately regulated in a murine model of patellar tendon injury

This study investigated the expression of Scleraxis in a murine model of patellar tendon injury in which the central third of the patellar tendon was unilaterally injured. The presence of tendon pathology was assessed using dual photon microscopy, conventional histology and microCT. Tendon pathology was also quantified noninvasively over a 12‐week period using high‐frequency ultrasound and laser Doppler flowmetry. Gene expression (Scx, Tnmd, and Col1a1) was determined at defined end‐points (1, 4, 8, and 12 weeks) using qPCR on RNA from individual patellar tendons on injured and uninjured sides. There was significant development of tendon pathology as gauged by ultrasound and laser Doppler over 12 weeks. Injured tendons demonstrated significant histological and microCT evidence of pathological change, and disorganized collagen with reduced density. The expression of Scx and Col1a1 was unchanged at 1 week, significantly upregulated at 4 and 8 weeks, and had returned to baseline by 12 weeks. Tnmd expression was unchanged at 1 week, and significantly increased at 4, 8, and 12 weeks. Patellar tendon injury was associated with marked increases in the expression of Scx, Tnmd, and Col1a1. Our data suggest new roles for Scleraxis in coordinating the response to injury in the pathogenesis of tendon disorders. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:289–296, 2011     

Portomesenteric venous thrombosis: a community hospital experience with 103 consecutive patients

Background

Portomesenteric venous thrombosis (PMVT) is uncommon but associated with ischemic bowel and mortality.

Objective

The purpose of this study was to determine the occurrence of PMVT in a community setting and evaluate current diagnosis, treatment, and outcomes.

Methods

Medical records of consecutive patients admitted to a community-based hospital diagnosed with PMVT were reviewed. Patients were divided into 2 groups: those diagnosed from 1997 to 2003 and those diagnosed from 2004 to 2009.

Results

One hundred three patients were included. The proportion of chronic PMVT diagnoses increased in the recent group (14% in contrast to 44%, P = .001). Treatment was more common in acute in contrast to chronic PMVTs (70% in contrast to 48%, P = .035). The median length of stay decreased over time (6 in contrast to 3 days, P = .004). Three patients underwent surgical intervention. Overall, 30-day mortality was 17% and did not change over time.

Conclusions

Diagnosis and treatment have changed with increased differentiation between acute and chronic PMVT; outcomes were similar. Surgical intervention was rarely necessary. Mortality is attributed to patient comorbidity rather than PMVT.     

Morbidity profile and functional outcome of modified facial translocation approaches for skull base tumors

The primary objective of this study was to evaluate morbidity associated with facial translocation approaches for skull base and results of various technical modifications. Forty consecutive patients who underwent facial translocation approaches for accessing skull base tumors from July 2005 to June 2010 were included in this study. There were 25 patients who underwent standard facial translocation, 4 patients medial mini, and 11 patients underwent extended facial translocation. Thirteen patients had benign disease and 27 patients had malignant disease. Resection was R0 in 36 and R1 in 4 patients. Most patients had acceptable cosmetic results. None of the patients had problems related to occlusion or speech and swallowing. The commonest complication observed was nasal crusting in 16 patients. Grade 2 trismus and exposure of mini plate was seen in three patients. Two patients developed necrosis of translocated bone. Three patients developed palatal fistula before modification of palatal incision. Facial translocation provides a satisfactory access for adequate clearance of skull base tumors with satisfactory aesthetic and functional results. With modifications of the surgical technique and implementation of new surgical tools, the morbidity of facial translocation approaches will continue to decrease.     

Robotic versus standard laparoscopic partial/wedge nephrectomy: a comparison of intraoperative and perioperative results from a single institution

PURPOSE: Laparoscopic partial/wedge nephrectomy, similar to laparoscopic radical prostatectomy, is a technically challenging procedure that is performed by a limited number of expert laparoscopic surgeons. The incorporation of a robotic surgical interface has dramatically increased the use of minimally invasive pelvic surgery such that robotic laparoscopic radical prostatectomy is commonly performed even by laparoscopically na?ve surgeons. This analysis compares the outcomes of our initial experience with robot-assisted laparoscopic partial nephrectomy (RLPN) performed by an experienced open surgeon to that of standard laparoscopic partial nephrectomy (LPN) performed by two experienced laparoscopic surgeons. PATIENTS AND METHODS: We reviewed the medical records of 11 consecutive patients who underwent 12 standard LPNs (EMM, RVC) (one patient had two unilateral tumors) and 10 consecutive patients (representing the first 11 of such robotic procedures performed at our institution) who underwent 11 RLPNs (one patient had bilateral tumors managed in an asynchronous manner) (DKO). RESULTS: The mean tumor size was 2.3 cm (range 1.7-6.2 cm) for LPN and 3.1 cm (range 2.5-4 cm) for RLPN. The mean total procedure time was 289.5 minutes (range 145-369 min) for LPN and 228.7 minutes (range 98-375 min) for RLPN (P=0.102). The mean estimated blood loss was 198 mL (range 75-500 mL) for LPN v 115 mL (25-300 mL) for RLPN (P=0.169). The mean warm ischemia time was 35.3 minutes (range 15-49 min) in the LPN group and 32.1 minutes (range 30-45 minutes) in the RLPN group (P=0.501). CONCLUSIONS: Introducing a robotic interface for laparoscopic partial/wedge resection allowed a fellowship-trained urologic oncologist with limited reconstructive laparoscopic experience to achieve results comparable to those for laparoscopic partial/wedge resection performed by experienced laparoscopic surgeons. In this regard, the learning curve appears truncated, similar to that with robot-assisted laparoscopic prostatectomy.     

Prevention of surgical site infection by antibiotic spraying in the operative field during cardiac surgery

OBJECTIVE: Despite the many procedures introduced to prevent surgical site infection during cardiothoracic surgery, serious infections still occur. We attempted to reduce surgical site infection by spraying antibiotic solution in the operative field--a procedure since introduced at 4 other Japanese institutions. METHODS: In the latter half of 1990, we began spraying an antibiotic solution of cefazolin (1g) and gentamicin (40 mg)/40 ml of saline placed in a 50 ml syringe and dispensed through an 18 G needle bent at 60 to 80 degrees to clean the wound during surgery. RESULT: No deep surgical site infections or deaths due to infection have occurred among the 502 patients undergoing cardiothoracic surgery under cardiopulmonary bypass at our hospital. This method was used in over 2,100 cases of similar procedures at 4 other institutions. There were 3 deaths due to severe surgical site infection (0.11%). At one institution treating over 1,000 cases a year, the incidence of death due to surgical site infection decreased significantly after this method was introduced. CONCLUSION: These preliminary experiences show that spraying antibiotic solution in the operative field reduces the risk of surgical site infection in cardiothoracic surgery.     

Heme oxygenase isoform-specific expression and distribution in the rat kidney

BACKGROUND: The heme oxygenase (HO) genes, HO-1 and HO-2, are the limiting steps in heme degradation and in the regulation of renal heme-dependent enzymes. Previously we reported that selective overexpression of renal HO-1 resulted in a decrease of microsomal heme and the cytochrome P450-dependent arachidonic acid metabolite, 20 HETE, a vasoconstrictor. The present study was undertaken to explore the relative expression and contribution of each of the HO isoforms to HO activity in the rat kidney. METHODS AND RESULTS. Renal HO activity increased above control levels after an injection of the inducers of HO activity, heme or SnCl2. Stannous Mesoporphyrin (SnMP), a nonselective inhibitor of HO, when used alone or in combination with heme or SnCl2, decreased HO activity. Heme alone and combined with SnCl2 decreased the levels of heme content by 13 and 35%, respectively. Western blot analysis showed that both SnCl2 and heme readily induced HO-1 protein, whereas HO-2 was constitutively expressed. Immunohistochemistry showed the distribution of the HO-1 isoform primarily in proximal convoluted tubules. Western blot analysis exhibited relatively higher levels of HO-1 in isolated proximal tubules and relatively higher HO-2 levels in the thick ascending limbs of the loop of Henle and preglomerular arterioles. In vivo administration of HO-1 and HO-2 antisense oligodeoxynucleotides further confirmed that HO-2, but not HO-1, contributed to the basal HO activity; however, following induction of HO with heme, antisense to HO-1, but not to HO-2, inhibited the induced levels of HO activity. CONCLUSION: These results suggest that HO-2 is constitutively expressed in the rat kidney mainly within tubular and arteriolar structures, and its activity may modulate physiological function under basal conditions. On the other hand, the basal levels of expression of HO-1 in the rat kidney are relatively low, and its contribution to HO activity and the regulation of hemoproteins such as cytochrome P450 become apparent only under pathophysiological conditions causing HO induction.