The pedipump: development status of a new pediatric ventricular assist device

The PediPump is a new rotary dynamic ventricular assist device designed specifically for pediatric applications. Although it is capable of providing support for adults, the small size of the PediPump makes it suitable for newborn circulatory support while retaining excellent hemodynamics. Current and future development plans include: (1) determination of the basic engineering requirements for hardware and control logic, including design analysis for system sizing, evaluation of control concepts and bench testing of prototypes; (2) performance of preclinical anatomical fitting studies using computed tomography-based three-dimensional modeling; and, (3) evaluation with animal studies to provide characterization and reliability testing of the device.     

Plasma concentrations of brain natriuretic peptide in patients with acute ischemic stroke

BACKGROUND: Acute blood pressure (BP) elevation and cardiac abnormalities are known to follow ischemic stroke. Brain natriuretic peptide (BNP), which is produced in response to such cardiovascular alterations, is expected to play a hemodynamic role. We measured plasma BNP concentrations in patients with cerebral infarction (CI) to determine the implications of BNP in acute ischemic stroke. METHODS: Eighty-eight patients with CI, 59 with essential hypertension, 44 with spontaneous intracerebral hemorrhage, 22 with asymptomatic atrial fibrillation (Af), and 20 age- and sex-matched healthy volunteers were recruited in the study. CI patients were divided into 2 subgroups either having Af (27 patients) or not (61 patients). BNP levels were repeatedly measured in 58 patients with CI. BNP levels were compared between ischemic subgroups categorized by size of infarction. Correlation was investigated between BNP levels and hemodynamic parameters. RESULTS: BNP levels in CI patients were significantly higher, but they decreased in the subacute period. BNP levels in CI patients without Af were correlated with mean arterial blood pressure (MAP) on admission or the degree of reduction in MAP at day 1, while in CI patients with Af BNP levels showed negative correlation with MAP on admission. Follow-up serum sodium levels in CI patients with Af were negatively correlated with BNP levels on admission. CONCLUSIONS: This study suggests the hemodynamic implications of BNP in acute ischemic patients.     

Reduction of radiation dose at HRCT of the temporal bone in children

PURPOSE: The purpose of this study was to reduce the radiation exposure of the eye lens in high resolution computed tomography (HRCT) of the temporal bone using an experimental phantom. MATERIALS AND METHODS: The HRCT image that was used for analysis was obtained by changing parameters including effective-mAs (E-mAs), distance coverage, and height of object in the Y-axis. Radiation exposure was measured to calculate equivalent doses by glass rod dosimeters that were fixed above the right orbit parallel to the body axis. Deterioration in image quality was evaluated by three radiologists and the following three-point rating method was employed: grade 1 (good image quality without diagnostic limitations), grade 2 (image was deteriorated, but there were no diagnostic limitations), and grade 3 (image was deteriorated with diagnostic limitations). RESULTS: Assuming that the equivalent dose was y (mSv), and E-mAs was x, a simple regression line, y=0.506x-0.494 (decision coefficient, R2=0.999), was obtained. A standard deviation (S.D.) less than 120 (E-mAs, 220-120) was judged as grade 1, an S.D. between 120 and 150 was judged as grade 2, and an S.D. higher than 150 was judged as grade 3, indicating that deterioration of the quality of images with reduced E-mAs affected the diagnosis by imaging at S.D. higher than 150. CONCLUSION: Radiation dose at the eye lens in HRCT could be reduced up to an equivalent dose corresponding to 70 mAs without compromising diagnostic quality in the phantom experiment.     

Increased accumulations of AMsopropyl-p-[123I]-iodoamphetamine related to tumefactive multiple sclerosis

We present a 21-year-old woman with tumefactive multiple sclerosis (MS) that exhibited a rapidly progressive course. There were multiple tumor-mimicking contrast-enhance lesions with surrounding edema and mass effect on magnetic resonance imaging. Both early and delayed brain single photon emission computed tomography (SPECT) with N-isopropyl-p-[123I]-iodoamphetamine demonstrated increased accumulations of the tracer and a high retention on the lesions. The SPECT findings represent a diagnostic pitfall for distinguishing MS from malignant brain tumors in patients with intracranial tumor-like lesions.     

Preclinical readiness testing of the Arrow International CorAide left ventricular assist system

BACKGROUND: Left ventricular assist system technologies are currently being developed as effective alternatives to cardiac transplantation. In this study, in vivo testing of the Arrow International CorAide left ventricular assist system was conducted to determine its preclinical readiness based on demonstrated system performance and biocompatibility. METHODS: Arrow International CorAide blood pump assemblies were implanted in 7 calves for 1-month (n = 4) and 3-month (n = 3) durations without the use of chronic anticoagulation therapy. Hemodynamic performance, physiologic pump control, end-organ function, and device-related adverse events were evaluated during the studies and at autopsy. RESULTS: Hemodynamics were stable in all cases with a mean pump flow of 4.1 +/- 0.8 L/min and a mean arterial pressure of 101 +/- 4 mm Hg. In all calves, renal and hepatic function remained normal with no incidence of hemolysis, infection, bleeding, or embolism. The CorAide physiologic control algorithm demonstrated appropriate pump speed and flow adjustments in response to physiologically induced inputs, and the system's external electronic components demonstrated no hardware or software malfunction. All 7 cases were sacrificed electively. Autopsy revealed no sign of end-organ disease on gross and histologic examinations, and no device failure, malfunction, or mechanical wear of the pump blood-bearing surfaces was found. CONCLUSIONS: The Arrow CorAide left ventricular assist system demonstrated effective pump performance and good biocompatibility with no incidence of device-related adverse events. This system has completed its preclinical readiness testing and is approved for clinical trials in Europe in 2003.     

Subcutaneous emphysema during endoscopic resection of the gastric mucosa

A 69-year-old male underwent endoscopic mucosal resection for an early gastric cancer under general anesthesia with sevoflurane and nitrous oxide. Because of gastro-intestinal gas insufflation for endoscopic visualization, abdominal distension was found remarkable and the peak inspiratory pressure increased from 20 cmH2O to 30 cmH2O. About 2.5 hours after initiation of the procedure, iatrogenic perforation was identified endoscopically and emphysema became apparent not only in the scrotum, but also in the subcutaneous tissues of the chest and neck. In order to ameliorate this complication, an emergent distal gastrectomy was performed involving laparotomy. Nitrous oxide should be avoided in endoscopic mucosal resection under general anesthesia to prevent intestinal distension and attention should be paid to subcutaneous emphysema as a sign of perforation of the gastro-intestinal tract.     

The trend and susceptibility to antibacterial agents of enterococcus species from urinary tract infections

OBJECTIVE: To determine the extent of drug-resistance among Enterococcus species we investigated in vitro experiments. METHODS: Studies were carried out on pure cultured of enterococci isolated from 8,575 urine specimens between 1990 and 2002. We had determined test strains to three kinds of species, which posses the urinary pathogenesis. Both an EF-agars and an ADH decarboxylase test performed the identification and speciation of the strains of enterococci. In vitro drug-susceptibility tests of enterococci were performed against the following antibiotics: ampicillin (ABPC), cefpirome (CPR), cefozopran (CZOP), imipenem/cilastatin (IPM/CS), minocycline (MINO), levofloxacin (LVFX), vancomycin (VCM), sulfamethoxazone/trimethoprim (ST), by employing the method for dilution antimicrobial susceptibility tests for bacteria that grow aerobically recommended by Japan Society of Chemotherapy. These drug-susceptibilities were shown susceptible, intermittent and resistant in according to National Committee for Clinical Laboratory Standards (M100-S12). RESULTS: The most common species isolated was E. faecalis (84.4%), followed by E. faecium (9.9%) and E. avium (5.6%). In E. faecium and E. avium, the sensitivity to ABPC has tended to improve from 1999. This tendency inverse correlated to decreasing dosage of PCs. There was much difference of resistant rate to IPM/CS between each species, and no correlation to used dosage of CBPs. The rate of resistance to MINO did not change during this period. 60% of E. faecalis had sensitivity to LVFX and the rate did not change during this period. In E. faecium, whose resistant rate to LVFX was 90%, the sensitivity has been improved to over 25% from 2001. The improved tendency of E. faecium to LVFX has inverse proportion to decreasing dosage of NQs. With the exception of a little bit VRE (VCM resistant Enterococci), almost of them had sensitivity to VCM. CONCLUSION: The emergence of enterococci with alarming rates of resistance concomitantly to multi-drugs highlights the need for a more rational and restricted use of antimicrobials, in order to minimize the selection and spread of such strains. An early detection of these problem pathogens is also important for preventing any treatment failures.     

Intracranial vertebral artery dissection with subarachnoid hemorrhage: clinical characteristics and outcomes in conservatively treated patients

OBJECT: Intracranial vertebral artery (VA) dissection with subarachnoid hemorrhage is notorious for frequent rebleeding and a poor prognosis. Nevertheless, some patients survive with a good final outcome. The factors associated with the prognosis of this disease are not fully understood and appropriate treatment strategies continue to be debated. The authors retrospectively evaluated the clinical features of conservatively treated patients to elucidate the relationship between the clinical and angiographic characteristics of the disease and final outcomes. METHODS: This study includes 24 patients who were treated by conservative methods between 1990 and 2000. Conservative treatment was chosen because of delayed diagnosis, poor clinical condition, or anatomical features such as bilateral lesions and contralateral VA hypoplasia. Of nine patients with an admission Hunt and Kosnik Grade I or II, eight had good outcomes (mean follow-up period 8 years and 4 months). All 15 patients with Grade III, IV, or V died and in 10 of these the cause of death was rebleeding. Among the 24 patients, 14 suffered a total of 35 rebleeding episodes; in 10 (71.4%) of these 14 patients rebleeding occurred within 6 hours and in 13 (93%) within 24 hours. Compared with the survivors, there was a female preponderance (0.022) among patients who died. These patients also had significantly shorter intervals between onset and hospital admission (p = 0.0067), a higher admission Hunt and Kosnik grade (p = 0.0001), a higher incidence of prehospitalization (p = 0.0296) and postadmission (p = 0.0029) rebleeding episodes, and a higher incidence of angiographically confirmed pearl-and-string structure of the lesion (p = 0.0049). CONCLUSIONS: In our series of preselected patients, poor admission neurological grade, rebleeding episode(s), and lesions with a pearl-and-string structure were predictive of poor outcomes. Our findings indicate that patients with these characteristics may be candidates for aggressive attempts to prevent rebleeding during the acute stage. Patients without these characteristics may be good candidates for conservative treatment, especially those who survive the acute phase without rebleeding.     

The coiled tail of the round-headed spermatozoa appears during epididymal passage in GOPC-deficient mice

Male mice deleting the gene encoding GOPC (Golgi-associated PDZ- and coiled-coil motif-containing protein) are infertile, showing globozoospermia with a coiled tail (Yao et al., 2002). We confirmed how and where tail anomalies were produced in spermatids and epididymal spermatozoa by light and electron microscopy. During spermiogenesis, tail formation occurred normally, but a defect was found at the posterior ring. Thereafter, remarkable sperm tail deformations were induced during epididymal passage. In the proximal caput epidiymidis, the tails remained normal and straight, but most of them coiled around the nucleus in the cauda epididymidis. Coiling is presumed to occur with the migration of the cytoplasmic droplet by the absence of the posterior ring. The connecting piece of the coiled tail was often dislocated or separated from the implantation fossa. Many mitochondria were separated from the outer dense fibers (ODFs) and formed a stratified mitochondrial sheath. Due to this, the distal part of the midpiece became bared of the mitochondrial sheath. The bared ODFs were often bent and disorganized. Tail deformities are attributed to weak or incomplete adhesion between the following structures: 1) plasma membrane and nuclear envelope at the posterior ring, 2) connecting piece and implantation fossa, and 3) mitochondria and ODFs. These defects result in a coiled tail, tail dislocation from the implantation fossa, and the stratified mitochondrial sheath accompanying bared ODFs in the midpiece, respectively. Thus the posterior ring is significant in preventing coiled tail formation. The GOPC-deficient spermatozoa provide a valuable model not only for head but also for tail anomalies.