Urethral Reconstruction Combined with Modified Urethrostomy in a Cat after Prepubic Urethrostomy

Background: In cats, urethral obstruction is generally caused by various reasons, including feline idiopathic cystitis, urethral crystals, urethral trauma, mucous plug, congenital or acquired anatomical deformity, and urolithiasis, especially in male cats. Depending on the severity and duration of clinical signs, immediate management including conservative or surgical therapy for restoration of urethral patency is required. Repetitive urethral obstruction due to intraluminal plugs, obstruction that cannot be resolved by medical management, and urethral strictures, trauma, or neoplasia should be managed by surgery. When the penile or pelvic urethra is ruptured or not long enough to mobilize the pelvic urethra to the perineal skin by repetitive perineal urethrostomy, prepubic urethrostomy is indicated. Potential complications of prepubic urethrostomy include urinary incontinence, peristomal dermatitis. In such cases, management of the peristomal site or placement of an artificial urethral sphincter have been reported previously. However, to date, urethral reconstruction using pre-existing penis has not been reported after prepubic urethral stricture following prepubic urethrostomy. The objective of this report is to describe surgical procedure of the urethral reconstruction combined with modified perineal urethrostomy in a cat with prepubic urethral stricture after prepubic urethrosotmy. Case: A 3-year-old castrated Scottish straight cat presented with dysuria after prepubic urethrostomy. The owner reported that the patient was diagnosed with urethral rupture, had undergone prepubic urethrostomy 2 months prior to presentation, and had persistent dysuria despite repetitive surgical revision of the prepubic urethral stoma at a local hospital. On physical examination, the preputial orifice and the penis appeared grossly normal. On ultrasonography, pericystic and periurethral fat had an edematous, striated appearance with alternating hyperechoic and anechoic regions. A small amount of free fluid was visible around the urethra. Abdominal radiography revealed a mildly distended bladder and loss of serosal detail around the area of the urinary bladder neck, consistent with inflammation and free fluid observed on ultrasonography. The retrograde urethrogram showed no leakage in either sites of the prepubic urethral orifice or the penis. Hence, complete urethral reconstruction with modified perineal urethrostomy was performed. The patient had normal urination at the 15-month follow-up. Discussion: Prepubic urethrostomy is beneficial for the patients whose penile or pelvic urethra is ruptured or not long enough to mobilize the pelvic urethra to the perineal. Complications of prepubic urethrostomy include skin necrosis around the stoma; urinary incontinence; stricture of the urethral stoma due to several reasons such as surgical-site irritation; poor mucosa–skin apposition; failure to provide tension-free stoma; and failure to expose wider pelvic urethra. In these cases, surgical management of the level of prepubic urethral stoma has been recommended by previous studies. However, no studies have been reported urethral reconstruction using pre-existing penile urethra in a patient with prepubic urethral stricture so far. To the author’s knowledge, this case is the first report describing urethral reconstruction in a cat with urethral stricture after prepubic urethrostomy. Keywords: cat, modified urethrostomy, prepubic urethrostomy, urethral reconstruction

Novel function of C5 protein as a metabolic stabilizer of M1 RNA

AbstractEscherichia coli RNase P is a ribonucleoprotein composed of a large RNA subunit (M1 RNA) and a small protein subunit (C5 protein). We examined if C5 protein plays a role in maintaining metabolic stability of M1 RNA. The sequestration of C5 protein available for M1 RNA binding reduced M1 RNA stability in vivo, and its reduced stability was recovered via overexpression of C5 protein. In addition, M1 RNA was rapidly degraded in a temperature-sensitive C5 protein mutant strain at non-permissive temperatures. Collectively, our results demonstrate that the C5 protein metabolically stabilizes M1 RNA in the cell

Pelvic Fracture in a Cat - Precontouring of the Plate Based on Allogenic 3D Model and its Application

Background: Pelvic fractures are commonly ecountered in cats. The ilium is included in approximately 50% of pelvic fractures in cats. Although conservative management of the pelvic fracture is known to have good prognosis, surgical fixation is recommended for the pelvic fractue with ilial fractures. 3D printing is an accurate digital modeling method by converting two-dimensional (2D) image into 3D model. 3D printing in veterinary medicine have been described in the various orthopedic diseases such angular limb deformities or fractures. The use of 3D model for presurgical planning is helpful to improve the results of complex surgical interventions. The objective of this study is to identify the usefulness of fabricating 3D models based on allogenic 2D data with aid of 3D printer program. Case: A 4-year-old spayed female domestic shorthair cat presented with hindlimb lameness. Radiography revealed left ilial body fracture with multiple fractures including left tuber ischium, pubic symphysis, and bilateral cranial ramuses of pubis. Digital imaging and communication in medicine (DICOM) files of the complete ilium were extracted from a CT scan of a healthy and castrated male cat of same breed. Volume rendering images were prepared by Slicer program based on DICOM files. After acquired 3D data were converted to STL (Standard Triangulation Language) file for the 3D printing machine, non-fracture involved area was removed except the left ilium using the Meshmixer® soft-ware and then data was stored as STL files again. The length of 3D model was adjusted to actual size using 3D printer firmware based on actual size of the ilial length. Subsequently, 3D modelling was performed using 3D printer. The plate was precontoured to conform to the lateral surface of the 3D model. Internal fixation using precontoured plate resulted in accurate bone alignment. The alignment of the ilium remained appropriate throughtout the follow-up period. Complete union was identified 6 months after surgery. Discussion: Although the most common method for the ilial fractures is the application of bone plates to the lateral side of the ilium, bone plate fixation is more challenging in cats owing to the small bone size and small surface area of the fracture sites compared to dogs. Therefore, it is important to make accurate presurgical planning for successful result of a surgery. 3D printing based on actual patient have several limitations including time for complete printing process and additional anesthetic episode to acquire computed tomography (CT) images. However, in simple cases, a presurgical CT scan may not be necessary if the plate can be precisely precontured based on the data from the other patient. In this way, the additional financial burden for CT examination also might be reduced. On the other hand, technical difficulty of utilizing hardware and software, and financial availability were another drawback. However, in this current study, most of limitations regarding conventional 3D printing based on actual patient were overcome by the application of the fused deposition modeling (FDM) technology with allogenic data. In the current study, total time for fabrication of 3D model based on FDM technology, was less than 3 h, which are much shorter than the time for conventional 3D printing. The difference of the ilial length between the actual patient and the 3D model was adjusted through the firmware program. Thus, differences of the conformation or size between the 3D model and the ilium of the patient was negligible during the surgery, although 2D images were not acquired from actual patient. Intraoperative contouring of the plate was not required. In conclusion, through presurgical plate contouring by the 3D bone template based on non-patient specific data, successful treatment of the ilial fracture was possible. Keywords: allogenic; cats; ilial fracture; 3D printing, 3D models, pilot study

Transient thermo-structural analysis of an insulated space structure

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1995.Includes bibliographical references (leaves 96-99).by Yool A. Kim.M.S

Thermal creak induced dynamics of space structures

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1999.Includes bibliographical references (p. 151-154).Space structures may be subjected to a continually changing thermal environment due to Earth eclipse transients and changes in the spacecraft orientation. During the transient thermal state, components in a structure may experience different amounts of thermal strain due to temperature gradients or coefficient of thermal expansion (CTE) mismatches. Such differential thermal strain can result in stress build-up, especially in statically indeterminate structures. If a nonlinear element, such as a friction dependent joint, is present, stress in the element builds up until the maximum load that can be sustained by friction is reached, at which point the element slips and releases some of the stored elastic energy. Such a nonlinear release mechanism will induce impulsive broadband and possibly high frequency loading to the system, in response to low frequency thermal excitations. This phenomenon is referred to as thermal creak. Nonlinear joints with freeplay, tensioning cables and pulleys, and other structural components that depend on friction and allow relative motion are all examples of potential creak elements that are common in space structures. An analytical and experimental investigation of the thermal creak phenomenon is presented. A generic model of a thermal creak element is developed to understand the mechanism and to identify the key parameters. The model captures the thermoelastic response, the friction behavior, and the dynamic response of a system. Key parameters that govern the response and quantify the parameters correlated with the energy storage, energy release and energy propagation are identified. The dynamic response is parametrically studied to qualitatively understand the range of behaviors. Two laboratory experiments were conducted to demonstrate thermal creak and to correlate with the model behavior. The first experiment, a joint characterization, focused on the local thermal creak response and the friction behavior. The model is shown to capture the nonlinear creak response over a range of loading conditions and trends seen in the experiment. The second experiment, a set of thermal tests on a representative deployable structure, investigated the structural response due to thermal creak. Thermal creak events were observed and the resulting dynamics were characterized. The results from the ground experiments and an on-orbit flight experiment conducted by Jet Propulsion Laboratory are used to assess the model and its applicability. The developed model and the experimental results provide a tool for developing thermal creak analysis techniques and mitigation strategies.by Yool A. Kim.Ph.D

The Irony of the Unchecked Growth of Higher Education in South Korea: Crystallization of Class Cleavages and Intensifying Status Competition

This study raises questions about the discrepancy between the praise for Korean education by international organizations and Koreans dissatisfaction with their education. First, the study identifies the main reason for the discrepancy as inequality at the level of higher education. To track down the formation of the current problem of educational inequality and excessive competition for status, the study evaluates the historical changes in South Koreas education system in the past several decades, focusing on the unchecked expansion of higher education. In doing so, the study shows how the aggregate decisions made by individuals and families, and the political dynamics of the past five decades have affected broad policy regarding educational stratification in South Korea. In the last section, the study presents what has been an empirical pattern of educational stratification in Korea reflecting all these social changes during the past five decades in Korea

Bezold-Jarisch Reflex Induced by Dopamine during Isoflurane Anesthesia in Small Dogs

Background: Unlike other major reflexes contributing to hemodynamic homeostasis, the Bezold-Jarisch reflex (BJR) paradoxically decreases heart rate (HR) and mean arterial pressure (MAP) despite hypotension. In the veterinary field, there are few reported cases of BJR induced by dopamine, which is often used to manage hypotension. Herein, 2 cases involving small dogs exhibiting BJR due to dopamine infusion during general anesthesia are described.Cases: Case 1: A 7-year-old, 7 kg, mongrel was referred for external skeletal fixator removal. The patient was premedicated with 0.3 mg/kg midazolam and 0.2 mg/kg butorphanol intravenously (IV). General anesthesia was induced with 6 mg/kg propofol and maintained with 1.6% isoflurane in oxygen. The patient was given 5 mL/kg/h of Hartmann’s solution IV. The respiratory rate (RR) was set to 9 breaths/min with a ventilator. The HR and MAP values were initially 120 bpm and 76 mmHg and gradually decreased to 70 bpm and 40 mmHg, respectively. The end-tidal CO2 partial pressure (ETCO2) was 39 mmHg, and the patient was administered 2.5 μg/kg glycopyrrolate IV. Then, 5 μg/kg/min dopamine was administered IV since the MAP did not improve. The HR, MAP, and ETCO2 increased to 113 bpm, 72 mmHg, and 47 mmHg, respectively. Subsequently, HR and MAP dramatically decreased to 50 bpm and 43 mmHg, respectively. A second-degree atrioventricular block was detected, prompting dopamine infusion discontinuation, and 2.5 μg/kg glycopyrrolate was again administered IV. Within 5 min, HR and MAP values normalized, and postoperative patient recovery was typical. Case 2: A 2-year-old, 8.6 kg, mongrel underwent surgery to correct a medial luxating patella of the right leg. The patient was premedicated with 0.3 mg/kg midazolam and 0.2 mg/kg butorphanol IV. Anesthesia was induced with 4 mg/kg propofol IV and maintained with 3% isoflurane in oxygen; 10 mL/kg/h of Hartmann’s solution was administered IV. Within 15 min, the patient’s HR and MAP values decreased from 120 to 107 bpm and 73 to 50 mmHg, respectively. The ETCO2remained approximately 39 mmHg, and RR decreased from 20 to 17 breaths/min. Dopamine was infused at a rate of 5 µg/kg/min. After 10 min, the MAP slightly increased from 50 to 57 mmHg, but the HR dramatically decreased from 107 to 62 bpm and the RR also dropped to 12 breaths/min. Further, a second-degree atrioventricular block was observed. Dopamine infusion was immediately discontinued, and 2.5 μg/kg glycopyrrolate was injected IV. As the HR returned to 94 bpm, the atrioventricular block disappeared, and the RR increased to 15 breaths/min. After general anesthesia was terminated, the patient recovered well.Discussion: Among drugs used for anesthesia, propofol and isoflurane may lower the MAP and HR. Therefore, HR or MAP decreases at the beginning of anesthesia are likely due to the drugs. Considering half-life, it is unlikely that propofol provoked sudden HR or MAP decreases at about 25 min post-induction. Isoflurane may also be ruled out since the hemodynamic disorder depended on dopamine injection. Sudden decreases in the HR, MAP, or RR after dopamine injection are not generally expected dopaminergic or adrenergic responses, which likely occur due to the vagal cardiopulmonary reflex suggesting the BJR resulting from activation of cardiac mechano- or chemoreceptors. To the best of our knowledge, there have been no reports of dopamine-mediated BJR in young or middle-aged, small dogs. The BJR has been observed in older, larger dogs and humans. In the patients described, body condition score may be considered when estimating the cause of the BJR. Since they scored 8/9, it is possible that obesity increased the risk of the BJR. This report described the clinical features and treatment outcomes in young or middle-aged, obese, small-sized dogs, whose hypotension or bradycardia was exacerbated by dopamine.Keywords: Bezold-Jarisch reflex, dopamine, hypotension, bradycardia, canine.

Comprehensive modeling of resistive switching in the Al/TiOx/TiO2/Al heterostructure based on space-charge-limited conduction

The reversible resistance switching (RS) effect of the Al/TiO x/TiO2/Al heterostructure is investigated in this study. This RS was attributed to space-charge-limited conduction (SCLC) as controlled by localized traps in the TiOx layer. The preexisting SCLC theory was extended to describe the abrupt resistance transition. An analytical model was developed with consideration of the ratio of free and trapped carrier density, which was extracted from the experimental data to show exponentially distributed traps in energy. The proposed model can be applicable to RS phenomena induced by interface-type traps in other material system.open231

Microscopic origin of bipolar resistive switching of nanoscale titanium oxide thin films

We report a direct observation of the microscopic origin of the bipolar resistive switching behavior in nanoscale titanium oxide films. Through a high-resolution transmission electron microscopy, an analytical TEM technique using energy-filtering transmission electron microscopy and an in situ x-ray photoelectron spectroscopy, we demonstrated that the oxygen ions piled up at top interface by an oxidation-reduction reaction between the titanium oxide layer and the top Al metal electrode. We also found that the drift of oxygen ions during the on/off switching induced the bipolar resistive switching in the titanium oxide thin films.Comment: 10 pages, 4 figure