IntraBrain Injector (IBI): A Stereotactic-Guided Device for Repeated Delivery of Therapeutic Agents Into the Brain Parenchyma

BACKGROUND

To deliver therapeutics into the brain, it is imperative to overcome the issue of the blood-brain-barrier (BBB). One of the ways to circumvent the BBB is to administer therapeutics directly into the brain parenchyma. To enhance the treatment efficacy for chronic neurodegenerative disorders, repeated administration to the target location is required. However, this increases the number of operations that must be performed. In this study, we developed the IntraBrain Injector (IBI), a new implantable device to repeatedly deliver therapeutics into the brain parenchyma.

METHODS

We designed and fabricated IBI with medical grade materials, and evaluated the efficacy and safety of IBI in 9 beagles. The trajectory of IBI to the hippocampus was simulated prior to surgery and the device was implanted using 3D-printed adaptor and surgical guides. Ferumoxytol-labeled mesenchymal stem cells (MSCs) were injected into the hippocampus via IBI, and magnetic resonance images were taken before and after the administration to analyze the accuracy of repeated injection.

RESULTS

We compared the planned vs. insertion trajectory of IBI to the hippocampus. With a similarity of 0.990 ± 0.001 (mean ± standard deviation), precise targeting of IBI was confirmed by comparing planned vs. insertion trajectories of IBI. Multiple administrations of ferumoxytol-labeled MSCs into the hippocampus using IBI were both feasible and successful (success rate of 76.7%). Safety of initial IBI implantation, repeated administration of therapeutics, and long-term implantation have all been evaluated in this study.

CONCLUSION

Precise and repeated delivery of therapeutics into the brain parenchyma can be done without performing additional surgeries via IBI implantation.

Epidemiology and clinical profiles of cutaneous graft versus host disease in allogeneic peripheral blood stem cell transplantation

INTRODUCTION

The epidemiology of cutaneous graft versus host disease (GVHD) in allogeneic peripheral blood stem cell transplantation (PBSCT) in Malaysia has not been described.

MATERIALS AND METHODS

We retrospectively analysed 691 allogeneic PBSCT patients between 2010-2017 in two centers.

RESULTS

The prevalence of cutaneous GVHD was 31.4% (217/691). No associations were detected with race, age or gender of donor and recipients. Cutaneous GVHD was associated with host cytomegalovirus (CMV) seropositivity (p<0.01), conditioning (p<0.01), GVHD prophylaxis (p=0.046) and survival (p<0.01). Majority developed the acute form (58.1%;126/217). Biopsies in 20.7% (45/217) showed 55.6% positivity for GVHD. Overall, involvement was non-severe. A majority demonstrated complete response (CR) to first-line corticosteroids (70.0%;152/217). Secondline therapies (extracorporeal phototherapy (ECP), psolaren ultraviolet A (PUVA), mycophenolate, tumour necrosis factor (TNF) inhibitors, interleukins inhibitors, or CD20 monoclonal antibodies) were required in 65/217, with 38.5% CR. Second-line therapy was associated with gender (p=0.042), extra-cutaneous GVHD (p=0.021), treatment outcomes (p=0.026) and survival (p=0.048). Mortality in cutaneous GVHD was 24.0% with severe sepsis being the leading cause at Day 100 (7.8%) and 5-years (7.8%), and relapsed disease at 2-years (32.7%). In steroid refractoriness, severe GVHD caused 30.8% mortality. In cutaneous GVHD, survival at Day 100 was 95.4%; 80.2% at 2-years and 73.1% at 5-years. The median survival in cutaneous GVHD was significantly shorter at 55 months, compared to those without GVHD at 69 months (p=0.001).

CONCLUSION

Cutaneous involvement is the commonest clinical manifestation of GVHD. A larger national study is warranted to further analyse severity and outcome of multiorgan GVHD, and factors associated with steroid refractoriness.

iNKT cells prevent obesity-induced hepatic steatosis in mice in a C-C chemokine receptor 7-dependent manner

Non-alcoholic fatty liver disease and non-alcoholic steatohepatitis are characterized by an increase in hepatic triglyceride content with infiltration of immune cells, which can cause steatohepatitis and hepatic insulin resistance. C-C chemokine receptor 7 (CCR7) is primarily expressed in immune cells, and CCR7 deficiency leads to the development of multi-organ autoimmunity, chronic renal disease and autoimmune diabetes. Here, we investigated the effect of CCR7 on hepatic steatosis in a mouse model and its underlying mechanism. Our results demonstrated that body and liver weights were higher in the CCR7^−/− mice than in the wild-type (WT) mice when they were fed a high-fat diet. Further, glucose tolerance and insulin sensitivity were markedly diminished in CCR7^−/− mice. The number of invariant natural killer T (iNKT) cells was reduced in the livers of the CCR7^−/− mice. Moreover, liver inflammation was detected in obese CCR7^−/− mice, which was ameliorated by the adoptive transfer of hepatic mononuclear cells from WT mice, but not through the transfer of hepatic mononuclear cells from CD1d^−/− or interleukin-10-deficient (IL-10^−/−) mice. Overall, these results suggest that CCR7⁺ mononuclear cells in the liver could regulate obesity-induced hepatic steatosis via induction of IL-10-expressing iNKT cells.

Fundus autofluorescence imaging patterns in central serous chorioretinopathy according to chronicity

PurposeTo investigate the time-period characteristics associated with morphologic changes in central serous chorioretinopathy (CSC) using fundus autofluorescence (FAF).Patients and methodsRetrospective, cross-sectional observational case series. Patients were classified into three groups: acute and chronic according to the onset of subjective symptoms of 6 weeks and sequelae patients who have history and symptoms but no serous retinal detachment (SRD). We compared FAF images to obtain characteristic findings according to the chronicity.ResultsA total of 52 eyes were included in this study. Acute CSC eyes were characterized by decreased FAF intensity at the leakage point in 13/22 eyes (56.5%) and staining patterns with various levels of fluorescence signal (hyperautofluorescent (10 eyes, 43.5%), hypoautofluorescent (1 eye, 4.3%), and minimal changes (12 eyes, 52.2%)) in the area of SRD. In chronic CSC eyes, hyperautofluorescent (14 eyes, 63.6%) or minimal changes (8 eyes, 36.4%) were observed in the area of SRD. Discrete dots with increased FAF intensity were observed in chronic CSC eyes (P<0.001). Eyes with sequelae of CSC had mixed FAF patterns over areas of retinal pigment epithelium (RPE) atrophy in seven eyes (100%, P<0.001)) and descending tracts which showed various FAF intensities according to the RPE and photoreceptor status (P<0.001).ConclusionFAF imaging patterns in CSC eyes differ according to the course of the disease, reflecting RPE and outer retinal changes. Detailed investigation using FAF could help to estimate the duration of CSC and determine the proper treatment modality.

Pharmacokinetics of daily versus monthly vitamin D3 supplementation in non-lactating women

This study compared serum cholecalciferol and 25-hydroxyvitamin D (25(OH)D) concentrations over four weeks in healthy, non-pregnant, non-lactating females aged 18-40 years, who were randomized to oral cholecalciferol 5000 international units (IU) daily for 28 days or a single dose of 150 000 IU. The study was conducted in Rochester, MN in March and April of 2010. We found no difference in mean 25(OH)D between treatment groups on study day 0 or day 28 (P=0.14 and 0.28, respectively). The daily group had 11 more days of detectable serum cholecalciferol than the single-dose group (P<0.001). There was no difference observed in cholecalciferol area under the curve (AUC28) between groups (P=0.49). However, the single-dose group had a significantly greater mean 25(OH)D AUC28 compared with the daily group (P<0.001).

Gene pathways and cell cycle-related genes in cultured avian primordial germ cells

Primordial germ cells (PGC) from early embryos are applicable to various kinds of research, including the production of transgenic animals. Primordial germ cells eventually migrate and differentiate into germ cells in the gonads, where they settle and rapidly proliferate. However, the proliferation rate of PGC is low in early embryos, and there are many significant pathways that mediate PGC activity. Therefore, in vitro culture of PGC from early embryos with efficient growth factors has been necessary. Recently, we cultured chicken PGC from embryonic d 2.5 with basic fibroblast growth factor and characterized the PGC through analysis of cell morphology, survival, proliferation, and apoptosis. However, large-scale analyses of genes expressed in cultured PGC and the genes involved in associated pathways are limited. The objective of the present investigation was to identify the signaling and metabolic pathways of expressed genes by microarray comparison between PGC and their somatic counterpart, chicken embryonic fibroblasts (CEF). We identified 795 genes that were expressed more predominantly in PGC and 824 genes that were expressed more predominantly in CEF. Among the predominant genes in PGC, 201 were differentially identified in 106 pathways. Among the predominant genes in CEF, 242 were differentially identified in 99 pathways. To further validate the genes involved in at least one candidate pathway, those involved in the cell cycle (12 predominant genes in PGC and 8 predominant genes in CEF) were examined by real-time PCR. To the best of our knowledge, this study is the first to investigate signaling and metabolic pathways in cultured PGC.

C-erbB-2 onco-protein expression in breast cancer: relationship to tumour characteristics and short-term survival in Universiti Kebansaan Malaysia Medical Centre

Breast cancer is the commonest cancer affecting females in Malaysia, contributing 31% of all newly diagnosed cases amongst Malaysian women. The present retrospective cohort study evaluated the relationship between cerbB- 2 onco-protein overexpression with various tumour characteristics and survival rate of breast cancer patients treated at the Universiti Kebangsaan Malaysia Medical Centre (UKMMC) between 1996-2000. CerbB- 2 oncoprotein overexpression was determined by immunohistochemistry (IHC) and tumors showing 2+ positivity were verified by Fluorescence In Situ Hybridization (FISH). One hundred and seventy two patients were eligible for the study with a short-term follow-up (median) of 5.1 years. C-erbB-2 oncoprotein overexpression correlated with lymph node positivity, oestrogen receptor (ER) and progesterone receptor (PR) negativity. Univariate analyses showed shorter disease free survival (DFS) and overall survival (OS) in patients with cerbB- 2 oncoprotein overexpression, Malay ethnicity, higher tumour grade, lymph node positivity, ER and PR negativity. In a subgroup of patients with c-erbB-2 oncoprotein overexpression, a shorter OS was observed in those with lymph node positivity, ER and PR negativity. In multivariate prognostic analysis, lymph node status, ER status and tumour grading were the strongest independent prognostic factors for both OS and DFS. However, c-erbB-2 status was not a significantly independent prognostic factor, even in subsets with lymph node positive or negative group. C-erbB-2 oncoprotein overexpression correlated well with lymph node status, ER and PR. Shorter OS and DFS were significantly observed in patients with c-erbB-2 oncoprotein overexpression. Lymph node status, ER status and tumour grading were the only three independent prognostic factors for OS and DFS in this study. Although c-erbB-2 expression is obviously important from a biological standpoint, multivariate analysis showed that it is not an independent prognostic indicator in breast carcinoma in the local population.

Parapharyngeal abscess complicated by endophthalmitis: a rare presentation of nasopharyngeal carcinoma

Objective:

We report an extremely rare case of nasopharyngeal carcinoma presenting as a lateral neck abscess complicated by endogenous bacterial endophthalmitis. Endogenous bacterial endophthalmitis complicating a neck abscess has not been reported in the recent English literature. We discuss the possible pathophysiology of neck abscess as a presenting feature of nasopharyngeal carcinoma, and the relationship between the parapharyngeal abscess and endogenous bacterial endophthalmitis.

Case report:

A middle-aged Chinese man presented with a left neck abscess associated with progressive vision deterioration and proptosis of the left eye. Incidentally, his random blood glucose was found to be elevated. Nasal endoscopy also revealed bilateral bogginess in the fossa of Rosenmuller. A diagnosis of left neck abscess with endogenous endophthalmitis associated with underlying diabetes mellitus was made. A computed tomography scan of the neck showed a left parapharyngeal abscess. Incision and drainage of the abscess together with biopsy of the nasopharynx was performed. Due to the non-salvageable condition of the left eye, evisceration was also performed. Pus culture studies from the neck abscess grew Klebsiella pneumoniae, and nasopharyngeal biopsy revealed undifferentiated carcinoma.

Conclusion:

Nasopharyngeal carcinoma is endemic in South East Asia and can have multiple, varied presentations. Therefore, in this setting, the clinician should have a high index of suspicion, especially in a patient from the Chinese ethnic group.

Analysis of testis-specific transcripts in the chicken

Sequences of candidate chicken testis-specific genes were analysed in order to develop a resource for functional genomic studies of the testis and male germ cells. Tentative consensus sequences (TC) containing expressed sequence tags expressed in testis libraries were selected from the TIGR Gallus gallus Gene Index, resulting in 292 TC. The transcriptional expression of these genes were evaluated in several chicken tissues, including testis and ovary. One hundred ten of the 292 TC were expressed in a testis-specific manner. Annotation of the TC using the Gene Ontology database terms showed that the proportion of testis-specific TC that were classified as having catalytic activity (within the molecular function branch) was higher than the proportion of total chicken TC classified in the same way. Our results may facilitate the investigation of testis-specific genes and their functional analysis in the chicken, as well as in other avian species.

Laparoscopic bowel injury in an animal model: monocyte migration and apoptosis

BACKGROUND

Unrecognized laparoscopic bowel injury has a delayed and covert presentation. Differences in monocyte migration and apoptosis between laparoscopic and open bowel injury were determined.

METHODS

For this study, 24 rabbits were divided into laparoscopic (n = 9) and open surgical (n = 9) bowel injury groups and a control group (n = 6) without bowel injury. Bowel injury was created using monopolar electrocautery. The animals were killed 1 day, 1 week, and 2 weeks after surgery. Monocyte migration assay was performed across a modified Boyden chamber. Apoptosis was assessed by DNA fluorescent stain H-33342.

RESULTS

In laparoscopy, monocyte apoptosis was decreased (p < 0.001), and migration was increased (p < 0.05), as compared with the open group. Apoptosis increased over time in both study groups, and was higher than in the control group (p < 0.001). Migration was decreased in both study groups as compared with the control group (p < 0.05)

CONCLUSIONS

These results suggest decreased immune system priming with laparoscopic bowel injury, which may contribute to the masking of relevant signs and symptoms of peritonitis.

No Panacea for Drainage after Percutaneous Nephrolithotomy

BACKGROUND AND PURPOSE

The optimal postoperative drainage system for patients undergoing percutaneous nephrolithotomy (PCNL) has not yet been determined. Each of the different tubes available has theoretical advantages and disadvantages. The objective of this study was to determine if any one system of post-PCNL drainage has any significant advantage over the others.

PATIENTS AND METHODS

Sixty patients were randomized to either a 24F Re-entry tube (Group 1), an 8F pigtail catheter (Group 2), or a double-J stent (Group 3) (N = 20 for all groups). The double-J stent patients also had an 18F Councill catheter as a nephrostomy tube, which was removed on the morning of postoperative day 1. The three groups were well-matched for age, stone size, operative time, and mean number of percutaneous tracts (P > 0.05 for all). Data collected included intraoperative findings, postoperative analog pain scores and narcotic usage, presence of extravasation on postoperative nephrostogram, presence of perinephric fluid on postoperative ultrasound scans, length of stay, and whether leakage from the nephrostomy site persisted more than 48 hours after tube removal.

RESULTS

There were no statistically significant differences among the three groups in terms of change in hematocrit or number of patients requiring blood transfusion; in the incidence of tube blockage, extravasation, or presence of perinephritic fluid; or in complication rates, length of hospital stay, or persistent leakage after tube removal. There was a strong trend to less postoperative leakage with the 8F pigtail than the Reentry tube (P = 0.05). Postoperative analog pain scores and narcotic usage were equivalent for all three groups. Patients Groups 1 and 2 were free of all tubes sooner than patients in Group 3 (P < 0.001).

CONCLUSIONS

This study did not demonstrate an overwhelming advantage of any one drainage system over the others. All three systems were equally tolerated by patients. There may be less chance of prolonged nephrostomy-site leakage with an 8F pigtail catheter.

Effect of Endo-GIA vascular staple size on laparoscopic vessel sealing in a porcine model

BACKGROUND

Two sizes of endoscopic gastrointestinal anastomosis (Endo-GIA) staples are currently available for vascular control. The purpose of this study was to compare the Endo-GIA 30-2.0 mm with the Endo-GIA 30-2.5 mm vascular staple.

METHODS

The renal blood vessels, aorta, and vena cava were divided laparoscopically using the Endo-GIA 30-2.0 and 30-2.5 mm in four pigs, respectively. The arterial and venous segments were harvested en bloc for ex vivo burst pressure studies.

RESULTS

Both 2.0-mm and 2.5-mm staples achieved vessel sealing at supraphysiologic mean burst pressures (> or =310 mmHg). There were no statistical differences between mean burst pressures of vessels stapled by 2.0-mm compared to 2.5-mm staples. Both staples sealed arteries up to 17 mm and veins up to 22 mm in diameter.

CONCLUSION

Endo-GIA 30-2.0 mm and 30-2.5 mm vascular staples are equivalent in sealing vessels at supraphysiologic mean burst pressures.

Are new-generation flexible ureteroscopes better than their predecessors?

OBJECTIVE

To compare two newly designed flexible ureteroscopes with their respective predecessors, to determine whether design advances have overcome the limitation of tip deflection, which may interfere with diagnosis and treatment of lower pole renal pathology.

MATERIALS AND METHODS

Two new-generation flexible ureteroscopes, the DUR-8 Elite (ACMI, Southborough, MA, USA) and 11278AU (Karl Storz Endoscopy, Culver City, CA, USA) were compared with their previous models, the ACMI DUR-8 and the Storz 11274AAU. Active tip deflection and irrigation flow rates with and without various endoscopic tools were assessed. Specifications, purchase prices and repair costs were obtained from each manufacturer. The field of view and screen image size of each ureteroscope were also compared.

RESULTS

The ACMI DUR-8 Elite and the Storz 11278AU had improvements of 79 degrees and 144 degrees, respectively, from their respective older models. Although the tip deflection of all ureteroscopes was compromised by inserting different endoscopic tools, these new instruments were less affected. With a 3 F basket inside the working channel, the ACMI DUR-8 Elite and the Storz 11278AU had only 0.7% and 2.8% loss of upward tip deflection, compared with their older models, at 9.6% and 5.0%, respectively. However, the flow rates of these new instruments were decreased.

CONCLUSION

The new flexible ureteroscopes have significantly better active tip deflection than previous models, both with and without endoscopic instrumentation inserted. However, improved flexibility is at the expense of decreased flow rates and higher purchase costs.

Remote percutaneous renal access using a new automated telesurgical robotic system

Previous clinical application of remote telesurgery has been the use of a novel system of video teleconferencing equipment along with remote control of a laparoscopic camera at distances over 11,000 miles. Recently, a robotic system has been developed to assist with percutaneous renal surgery. This robot has been incorporated into the telesurgical system to allow remote needle placement into the renal collecting system under radiological guidance. The main component of the telesurgical system is a low degree of freedom robot called "PAKY" (percutaneous access of the kidney). It is custom designed for fluoroscopic guided percutaneous needle insertion into the renal collecting system. The robot is a six-degrees of freedom device. However, when the skin entry site is fixed and held in position, only two degrees of freedom are required to orient the needle in the correct plane for accurate insertion. Remote control of the robot was accomplished over a plain old telephone system (POTS) line. On June 17, 1998, the first remote telerobotic percutaneous renal access procedure was performed between the Johns Hopkins Hospital, Baltimore, Maryland, and Tor Vergata University, Rome, Italy. This new telesurgical robot was successful in term of obtaining percutaneous access within 20 min, with two attempts to obtain entry into the collecting system. This robot represents the first system for performing remote telesurgical interventions in the kidney and demonstrates the feasibility and safety of assisting accurate and rapid needle access to the kidney during percutaneous procedures.

Management of malignant extrinsic compression of the ureter by simultaneous placement of two ipsilateral ureteral stents

BACKGROUND AND PURPOSE

Extrinsic ureteral obstruction caused by various malignancies often necessitates urinary diversion. The use of single ureteral stents as a form of urinary diversion results in a high failure rate, while the use of two ipsilateral stents has shown promising results. We report our experience using the latter technique.

PATIENTS AND METHODS

Between 1996 and 2001, four male and three female patients with a mean age of 65 years (range 37-95 years) who had extrinsic compression of the ureters underwent single stent management to relieve obstruction. Ureteral obstruction was secondary to prostate cancer (N = 3), cervical cancer (2), non-Hodgkin's lymphoma (1), and transitional-cell cancer of the bladder and ureter (1). After failure of such management, two 7F stents or a combination of 8F/6F double-J ureteral stents were placed. The stents were changed every 4 to 6 months. Follow-up included serial renal ultrasound scans and serum creatinine measurements.

RESULTS

Ureteral stricture length ranged from 2 to 4 cm. Insertion of two double-J ureteral stents in a single ureter was successful in all cases. During the mean follow-up of 16 months (range 1-38 months), the ureteral stents were tolerated by all patients, without significant discomfort. Marked improvement of hydronephrosis and alleviation of flank pain was noted in all patients. Three patients have died at 1 to 3 months. Renal function improved, with a mean decline in the serum creatinine concentration from 3.2 mg/dL to 1.48 mg/dL in the five patients tested.

CONCLUSION

Simultaneous placement of two double-J ureteral stents for the management of ureteral obstruction secondary to a malignancy is a safe and effective technique.

Management of ureteral stricture disease during laparoscopic ureteroneocystostomy

BACKGROUND AND PURPOSE

Laparoscopic surgery has many applications in urology. The surgical management of obliterative ureteral stricture disease using laparoscopy has not been widely reported. We recently implemented this technique in an adult patient with an obliterative ureteral stricture.

METHODS

A transperitoneal refluxing right ureteral reimplantation was performed using the Endostitch device. Placement of the new ureteral orifice in the bladder was monitored by simultaneous cystoscopy and laparoscopy. The anastomosis was performed without tension, torsion, or angulation and was stented for 4 weeks.

RESULTS

The operative time was 233 minutes. The blood loss was minimal. There were no intraoperative complications, and the postoperative hospital course was uneventful.

CONCLUSION

Laparoscopic ureteral reimplantation is a safe and feasible technique. Cystoscopic determination of the neoureteral orifice is helpful. The Endostitch device is a useful adjunct in this procedure.

Retroperitoneoscopic radiofrequency ablation of a solid renal mass

PURPOSE

To report a new technique for radiofrequency (RF) ablation of a solid renal mass.

PATIENT AND METHODS

An 83-year-old man with a history of chronic renal insufficiency was found to have solid mass in the right kidney. Retroperitoneoscopic localization of the renal mass was accomplished using intraoperative ultrasonography. The lesion was treated with a 14-gauge RITA Starburst XL probe (Rita Medical Systems, Inc., Mountain View, CA).

RESULTS

The total treatment time included two cycles of 5.5 minutes. There were no intraoperative complications. Tissue desiccation was noted during treatment. A CT scan 48 hours after ablation showed a decrease in the density of the lesion suggestive of coagulation necrosis. The postoperative hospital course was uneventful.

CONCLUSION

The retroperitoneal laparoscopic technique is a feasible approach to performing RF ablation of a solid renal mass. It facilitates direct insertion of the RF probe, allows viewing and avoidance of adjacent structures such as bowel, and permits better staging by enabling biopsy of perirenal fatty tissue.

Molecular cloning and functional expression of bovine brain GABA transaminase

We isolated a cDNA that encodes the bovine brain gamma-aminobutyrate transaminase (GABA-T; EC 2.6.1.19) from the lambda gt 11 cDNA library, which showed a high degree of sequence similarity to the corresponding enzymes from various sources. Northern blot analysis revealed two differentially expressed GABA-T transcripts of approximately 2.0 and 6.0 kb in the bovine tissues. Southern blot analysis indicates that the two GABA-T transcripts are encoded in a greater-than 10-kb, single-copy gene. Bovine GABA-T cDNA was expressed in E. coli using the pGEX bacterial- expression vector system. The overexpressed GABA-T was enzymatically active after purification, and it had very similar kinetic parameters when compared with those of other mammalian GABA-Ts.

Three-dimensional structures of protein-protein complexes in the E. coli PTS

The bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) includes a collection of proteins that accomplish phosphoryl transfer from phosphoenolpyruvate (PEP) to a sugar in the course of transport. The soluble proteins of the glucose transport pathway also function as regulators of diverse systems. The mechanism of interaction of the phosphoryl carrier proteins with each other as well as with their regulation targets has been amenable to study by nuclear magnetic resonance (NMR) spectroscopy. The three-dimensional solution structures of the complexes between the N-terminal domain of enzyme I and HPr and between HPr and enzyme IIA(Glc) have been elucidated. An analysis of the binding interfaces of HPr with enzyme I, IIA(Glc) and glycogen phosphorylase revealed that a common surface on HPr is involved in all these interactions. Similarly, a common surface on IIA(Glc) interacts with HPr, IIB(Glc) and glycerol kinase. Thus, there is a common motif for the protein-protein interactions characteristic of the PTS.

NF-kappa B mediates the adaptation of human U937 cells to hydrogen peroxide

Low doses of oxidative stress can induce cellular resistance to subsequent higher doses of the same stress. By using human U937 leukemia cells, we previously demonstrated that H(2)O(2) can induce such an adaptive response without elevating the cellular capacity to degrade H(2)O(2), and were able to confer the cells a cross-resistance to an H(2)O(2)-independent lethal stimulus, C(2)-ceramide. In this study, it was found that the adaptation is accompanied by the translocation of cytoplasmic NF-kappa B to the nuclei. This event was promoted or abolished when either IKK alpha or a dominant negative mutant of I kappa B, respectively, was overexpressed. The overexpression of IKK alpha also resulted in the suppression of H(2)O(2)-induced cell death and DNA fragmentation, whereas these events were accelerated by the expression of the I kappa B mutant. The protective effect of IKK alpha was accompanied neither by an elevation of protein levels of various antioxidant enzymes such as catalase, superoxide dismutase, and glutathione peroxidase, nor by an increase in the cellular capacity to consume H(2)O(2). Moreover, the overexpression of IKK alpha resulted in an enhancement of H(2)O(2)-induced resistance to C(2)-ceramide. The overall data suggest that NF-kappa B mediates the H(2)O(2) adaptation induced in a manner independent of H(2)O(2)-degrading activity.

Brain succinic semialdehyde dehydrogenase: identification of reactive lysyl residues labeled with pyridoxal-5'-phosphate

An NAD+ dependent succinic semialdehyde dehydrogenase from bovine brain was inactivated by pyridoxal-5'- phosphate. Spectral evidence is presented to indicate that the inactivation proceeds through formation of a Schiff's base with amino groups of the enzyme. After NaBH(4) reduction of the pyridoxal-5'-phosphate inactivated enzyme, it was observed that 3.8 mol phosphopyridoxyl residues were incorporated/enzyme tetramer. The coenzyme, NAD+, protected the enzyme against inactivation by pyridoxal-5'-phosphate. The absorption spectrum of the reduced and dialyzed pyridoxal-5'-phosphate-inactivated enzyme showed a characteristic peak at 325 nm, which was absent in the spectrum of the native enzyme. The fluorescence spectrum of the pyridoxyl enzyme differs completely from that of the native enzyme. After tryptic digestion of the enzyme modified with pyridoxal-5'-phosphate followed by [3H]NaBH4 reduction, a radioactive peptide absorbing at 210 nm was isolated by reverse-phase HPLC. The sequences of the peptide containing the phosphopyridoxyllysine were clearly identical to sequences of other mammalian succinic semialdehyde dehydrogenase brain species including human. It is suggested that the catalytic function of succinic semialdehyde dehydrogenase is modulated by binding of pyridoxal-5'-phosphate to specific Lys(347) residue at or near the coenzyme-binding site of the protein.

Biomicroscopic vitreous observation using a 3 CCD video camera and a personal computer for image capture and archiving

The purpose of this study is to evaluate the clinical usefulness of a newly developed biomicroscopic vitreous observation system. Vitreous observation was performed in 300 eyes with age- or disease-related vitreous changes using a 3 CCD video camera mounted on a slit-lamp biomicroscope and connected to a personal computer for real-time observation and especially for the capture and archiving of images. Various types of fundus lenses were used to scan the vitreous status systemically from the posterior pole to the vitreous base. This system allowed us to obtain and immediately review the images of the vitreoretinal relationship. The image quality was sufficient for clinical evaluation of the vitreous status. We were able to identify some variations of posterior vitreous detachments and clarify the changes of the vitreoretinal interface in the study eyes. This system is very useful for the dynamic observation and documentation of vitreous images in order to determine the role of vitreous in many vitreoretinal disorders. Furthermore it is more convenient and affordable than previous methods.

Laparoscopic live donor nephrectomy: outcomes equivalent to open surgery

A shortage of kidney donors has contributed to the interest in laparoscopic live-donor nephrectomy. Three transperitoneal ports are used, as is an AESOP robot. To maintain urine flow, the donor is kept volume expanded during the procedure, and the pneumoperitoneum pressure is minimized. The most critical and hazardous part of the surgery is dissection of the renal artery and vein. Abundant periureteral tissue should be left to protect the blood supply. Harvest of the right kidney is more difficult. Placing the extraction incision in the right upper quadrant and using a Satinsky clamp instead of a stapling device at the origin of the renal vein will provide maximum venous length and help prevent postoperative thrombosis of the allograft. In the first 175 laparoscopic renal harvest procedures at Johns Hopkins, the complication rate was 14%, the rate of open conversion was 2%, and 3% of the patients required transfusions. These rates improved with experience. There was no significant difference in the performance of the allografts or the recovery of the recipients from what is seen after open kidney harvest. Wider acceptance of laparoscopic renal harvest will increase the number of donors and will be helped by development of methods and devices that shorten the learning curve.

In vivo measurement of tumor conductiveness with the magnetic bioimpedance method

A noninvasive electromagnetic method has been developed that can effectively measure the in-vivo conductivity difference between rat tumor lines having a low and high metastatic potential. These tumor lines are used in the study of human prostate tumor.

International telementoring: a feasible method of instruction

Since the advent of improved telecommunication technology, greater bandwidth capability, medical robotics, and digital video technology, telemedicine has evolved. Telesurgical telementoring is an advanced form of telemedicine. An experienced surgeon can conduct, guide and mentor a second surgeon from a remote location. The historical method of teaching surgeons new operative techniques is exemplified in residency training: having individuals work with experienced teachers. Unfortunately, it is impractical for these specialized minimally invasive surgeons to travel and proctor generally trained surgeons each time a new surgical technique is developed. Telesurgical telementoring may represent a method to teach and mentor remote surgeons, as well as allow educational opportunities.

Identification of copper ligands in Aspergillus oryzae tyrosinase by site-directed mutagenesis

Copper ligands of the recombinant tyrosinase from the fungus Aspergillus oryzae expressed in Saccharomyces cerevisiae or Escherichia coli were identified by site-directed mutagenesis. The recombinant protyrosinases expressed in S. cerevisiae were assayed for catalytic activities of mono-oxygenase and L-dopa oxidase at pH 5.5 after acid shock at pH 3.0. Replacements of His-63, His-84, His-93, His-290, His-294, His-332 or His-333 with asparagine resulted in mutant enzymes exhibiting no activities. The site-directed mutant Cys82Ala showed that Cys-82 was also an essential residue for the activity. We obtained homogeneous preparations of activated tyrosinases from mutated thioredoxin fusion gene products expressed in E. coli by acid shock. The copper contents of engineered mutants and wild-type enzyme expressed in E. coli were determined by atomic absorption spectrophotometry. The wild-type enzyme contained 2 g-atoms of copper/mol of the subunit. The His63Asn, His84Asn, His93Asn, His290Asn, His294Asn, His332Asn, His333Asn or Cys82Ala substitution decreased copper binding by approx. 50%, indicating that the mutants contain only approx. 1 g-atom of copper/mol of the subunit. The five mutants His63Asn, His93Asn, His290Asn, His294Asn and Cys82Ala contain only one copper ion, which is fully detectable by EPR. From the correlation of g( parallel) and (Cu)A( parallel), we deduced that the nitrogen or sulphur donors in the copper ligands should be in a square or a distorted tetrahedral geometric environment. In further atomic absorption spectrophotometry experiments, no copper atom was observed in the seven double mutants His63Asn/His290Asn, His63Asn/His294Asn, His63Asn/His332Asn, His63Asn/His333Asn, Cys82Ala/His290Asn, His84Asn/His333Asn and His93Asn/His290Asn. We propose a new structure of active sites of tyrosinase from A. oryzae: the most likely binding sites of tyrosinase for Cu(A) are His-63, His-84 and His-93, with the remaining conserved Cys-82 providing the fourth ligand. Cu(B) liganded by four histidine residues, His-290, His-294, His-332 and His-333, is identified as new binding motif of Cu(B).

Laparoscopic telesurgery between the United States and Singapore

INTRODUCTION

Telemedicine is the use of electronic digital signals to transfer information from one site to another. With the advent of a telepresence operative system and development of remote robotic arms to hold and manoeuvre the laparoscope, telemedicine is finding its role in surgery, especially laparoscopic surgery. CLINICAL FEATURES AND TREATMENT: We report two successful cases of laparoscopic surgery--radical nephrectomy and varicocelectomy for a 3-cm renal tumour and for bilateral varicoceles causing pain, where a less experienced laparoscopic surgeon in Singapore was telementored by an experienced laparoscopic surgeon located remotely in the United States. Both patients recovered uneventfully and returned home on postoperative day 4 and on the day of surgery, respectively.

OUTCOME

This study demonstrates that telementored laparoscopic systems are feasible and safe, between countries halfway across the world.

CONCLUSIONS

As the Internet expands in utility and the cost of higher bandwidth telecommunication lines decreases, even to remote countries, telementoring systems will become more affordable and may potentially pave the way for advanced surgical and laparoscopic applications and training for the future.

Effect of time delay on surgical performance during telesurgical manipulation

BACKGROUND

Telementoring allows a less experienced surgeon to benefit from an expert surgical consultation, reducing cost, travel, and the learning curve associated with new procedures. However, there are several technical limitations that affect practical applications. One potentially serious problem is the time delay that occurs any time data are transferred across long distances. To date, the effect of time delay on surgical performance has not been studied.

MATERIALS AND METHODS

A two-phase trial was designed to examine the effect of time delay on surgical performance. In the first phase, a series of tasks was performed, and the numbers of robotic movements required for completion was counted. Programmed incremental time delays were made in audiovisual acquisition and robotic controls. The number of errors made while performing each task at various time delay intervals was noted. In the second phase, a remote surgeon in Baltimore performed the tasks 9000 miles away in Singapore. The number of errors made was recorded.

RESULTS

As the time delay increased, the number of operator errors increased. The accuracy needed to perform remote robotic procedures was diminished as the time delay increased. A learning curve did exist for each task, but as the time delay interval increased, it took longer to complete the task.

CONCLUSIONS

Time delay does affect surgical performance. There is an acceptable delay of <700 msec in which surgeons can compensate for this phenomenon. Clinical studies will be needed to evaluate the true impact of time delay.

Feasibility of ablating normal renal parenchyma by interstitial photon radiation energy: study in a canine model

BACKGROUND AND PURPOSE

A miniature photon radiosurgery system (PRS) has been described as an alternative to surgical resection and external-beam radiation for tumors and may now offer an alternative for ablation of renal lesions. We evaluated the feasibility of ablation by PRS in a normal parenchyma canine model.

MATERIALS AND METHODS

Twelve mongrel dogs were used in this survival study. In the left and right kidneys of each animal, a peripheral lesion and central-hilar lesion, respectively, were induced with PRS. The probes were placed in the renal parenchyma, and local radiation of 15 Gy at a radius of 1.3 cm was delivered over 10 minutes. Serum electrolytes were measured serially. Computed tomography scans were obtained, and the animals were sacrificed for pathologic correlation. In a separate study, the liver received three additional treatments of 10 to 20 minutes of radiation.

RESULTS

Eleven dogs survived this 6-month study and were sacrificed as scheduled. One animal expired after 2 weeks from radiation-induced fulminant hepatic failure with normal renal function. No other complications were observed. The average lesion size was 2.5 cm in diameter. Histologic analysis confirmed coagulative necrosis with sharp demarcation from the surrounding parenchyma.

CONCLUSION

Preliminary studies demonstrate the feasibility of PRS ablation of the renal parenchyma. Further tumor model testing will be important to determine the ultimate efficacy of local photon radiation energy.

Retroperitoneal access for transperitoneal laparoscopy in patients at high risk for intra-abdominal scarring

BACKGROUND AND PURPOSE

Adhesions from prior extensive open abdominal surgery can make initial transperitoneal access for laparoscopy hazardous. An alternative to open port placement is a retroperitoneal approach to the peritoneal cavity. We describe our retroperitoneal access for transperitoneal laparoscopy and evaluate the success of the subsequent laparoscopic procedure.

PATIENTS AND METHODS

Eight patients with a history of abdominal surgery have undergone retroperitoneal access to the peritoneum prior to a laparoscopic urologic procedure. With the patient in a lateral decubitus position, the retroperitoneum is entered with a 10-mm Visiport device (US Surgical Corp., Norwalk, CT) along the posterior axillary line. A working space is bluntly created, the peritoneum identified anterior to the colon, and the endoscope passed through a peritoneotomy. The abdomen is then inspected, transperitoneal ports are strategically placed under direct vision, and the intended procedure is commenced.

RESULTS

In all cases, retroperitoneal access to the peritoneum and subsequent trocar placement was successful. In five cases, the intended procedure was completed laparoscopically. In a case of bilateral ureterolysis, one side was completed laparoscopically; however, the other required open conversion. In two nephrectomies for xanthogranulomatous pyelonephritis (XGP), open conversion was necessary because of fibrosis.

CONCLUSION

Retroperitoneal access to the peritoneal cavity permits safe and effective port placement when previous abdominal surgery makes initial transabdominal access difficult. However, despite successful access, in patients at risk for extensive perinephric fibrosis (e.g., XGP), a high incidence of open conversion may be expected.

Implementation of spectral width Doppler in pulsatile flow measurements

In this paper, we present an automatic beam-vector (Doppler) angle and flow velocity measurement method and implement it in pulsatile flow measurements using a clinical Doppler ultrasound system. In current clinical Doppler ultrasound flow velocity measurements, the axis of the blood vessel needs to be set manually on the B-scan image to enable the estimation of the beam-vector angle and the beam-vector angle corrected flow velocity (the actual flow velocity). In this study, an annular array transducer was used to generate a conical-shaped and symmetrically focused ultrasound beam to measure the flow velocity vectors parallel and perpendicular to the ultrasound beam axis. The beam-vector angle and flow velocity is calculated from the mode frequency (f(d)) and the maximum Doppler frequency (f(max)) of the Doppler spectrum. We develop a spectrum normalization algorithm to enable the Doppler spectrum averaging using the spectra obtained within a single cardiac cycle. The Doppler spectrum averaging process reduces the noise level in the Doppler spectrum and also enables the calculation of the beam-vector angle and flow velocity for pulsatile flows to be measured. We have verified the measurement method in vivo over a wide range of angles, from 52 degrees to 80 degrees, and the standard deviations of the measured beam-vector angles and flow velocities in the carotid artery are lower than 2.2 degrees and 12 cm/s (about 13.3%), respectively.

Nuclear morphometry and prognosis in favorable histology Wilms' tumor: A prospective reevaluation

PURPOSE

This study was designed to evaluate the ability of a previously published nuclear morphometry discriminant function to predict disease-free survival in patients with Wilms' tumor.

PATIENTS AND METHODS

We identified 218 patients with stage I-IV Wilms' tumor of favorable histology who were entered onto the National Wilms' Tumor Study (NWTS) between January 1, 1990 and April 15, 1994. The nuclear morphometry score was calculated for each patient as follows: MV(f) = (0.02 x AGE) + (1.17 x SNRF) + (90.6 x LEFD) - 94, with AGE denoting age at diagnosis in months, SNRF the skewness of the nuclear roundness factor, and LEFD the lowest value of nuclear ellipticity as measured by the feret diameter method. Relative risks of relapse were estimated for the total score and for each of its components. Sensitivity and specificity were determined for the criterion of "MV(f) is greater than -0.35" as a predictor of relapse.

RESULTS

By contrast with previously published results, neither the SNRF nor the LEFD made any contribution to the prediction of disease-free survival. Sensitivity and specificity of the criterion of "MV(f) is greater than -0.35" were 71% and 56%, respectively.

CONCLUSION

Re-evaluation of a published nuclear morphometry score showed that it did not predict disease-free survival in patients with Wilms' tumor. The earlier study very likely overestimated the predictive power of nuclear morphometry by using the same data set both to develop the score and to evaluate its properties. Because of the huge number of combinations of nuclear morphometry measurements that may enter into the multivariate discriminant function, use of appropriate statistical methods is essential to estimate accurately the sensitivity and specificity.

The EndoHand: comparison with standard laparoscopic instrumentation

Laparoscopic instrumentation is constantly being refined in an attempt to achieve the proficiency, flexibility, and tactile feedback that would be available if the human hand were small enough to be used in laparoscopic surgery. The EndoHand (DAUM GmbH, Schwerin, Germany) is a novel laparoscopic three-fingered hand developed as an advancement over standard laparoscopic tools. Grasping and manipulation ability, dexterity, and tactile feedback were compared with those of current laparoscopic instrumentation. Experiments included measurement of achievable angles of approach to a fixed point behind a 2-cm-tall obstruction, completion time and error rates during a pelvic trainer dexterity task, and tactile feedback using a device invented to simulate tissue resistance. Subjectively, the EndoHand was able to pick up a range of objects similar to those graspable by a Babcock clamp. More complex types of manipulation were possible with the EndoHand because of its wrist joint. The range of approach angles to the fixed point was 35 degrees to 90 degrees with the EndoHand and 70 degrees to 90 degrees with the straight instruments. The dexterity of the EndoHand was significantly less than that of the other two instruments, as measured by time (P = 0.0002) and errors (P = 0.02). Standard instruments were also more accurate in the tactile feedback trials (P = 0.02). The EndoHand is a prototype of a unique new generation of laparoscopic instruments. Although it falls short in both dexterity and tactile feedback, significant promise is shown in its ability to perform sophisticated manipulation of objects and its flexibility to work at a larger range of angles to the target tissue. The EndoHand may be most useful on the nondominant hand of the surgeon to assist with positioning and holding tissue in a specific orientation. Clinical trials will determine its eventual role in laparoscopic surgery.

Bioimpedance: novel use of a minimally invasive technique for cancer localization in the intact prostate

BACKGROUND

Prostate cancer is presently diagnosed by transrectal ultrasound (TRUS)-guided sextant needle biopsy. While echo texture of the tissue can prompt localization of tumor, it is presently imprecise. From 50-75% of men biopsied, based on an abnormal digital rectal examination (DRE) or elevated prostate-specific antigen (PSA) level, have negative biopsy results. Improvements in tumor localization during TRUS-guided prostate biopsy are greatly needed. Bioimpedance is an electrical property of biologic tissue. Electric current is limited in living tissue by highly insulating cell membranes; however, different tissue architecture such as cancer may impede current differently and allow detection of differences between normal and abnormal or malignant prostate tissue. Our goal was to assess the utility of bioimpedance measurements in differentiating tumor from normal prostatic tissue in an ex vivo model.

METHODS

Bioimpedance was measured in six ex vivo prostates, which were removed for clinically localized prostate cancer. Two bioimpedance needles, 1 mm apart, were inserted 3 mm into the posterior surface of the prostate an average of 16 times per gland. Frequencies ranging from 100 kHz-4 MHz were used to obtain 594 bioimpedance measurements from the six glands. These measurements were then correlated with histology to determine the presence or absence of prostate cancer.

RESULTS

Prostate cancer was found to have a higher impedance, of 932+/-170 ohms, compared to areas of no cancer within the same prostate, 751+/-151 ohms, P < 0.0001, at 2 MHz. This phenomenon was observed across all frequencies tested.

CONCLUSIONS

This study demonstrates for the first time application of bioimpedance to distinguish areas of prostate cancer from areas of normal prostate. This technology may improve identification and localization of cancer within the prostate. Moreover, bioimpedance can potentially guide needle placement during prostate biopsy and thus improve sampling of tumors. Currently, our ex vivo model is limited by variables such as temperature and lack of blood flow. Further studies in an in vivo model will be needed to assess their effect.

Different antigenic reactivities of bovine brain glutamate dehydrogenase isoproteins

The structural differences between two types of glutamate dehydrogenase (GDH) isoproteins (GDH I and GDH II), homogeneously isolated from bovine brain, were investigated using a biosensor technology and monoclonal antibodies. A total of seven monoclonal antibodies raised against GDH II were produced, and the antibodies recognized a single protein band that comigrates with purified GDH II on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot. Of seven anti-GDH II monoclonal antibodies tested in the immunoblot analysis, all seven antibodies interacted with GDH II, whereas only four antibodies recognized the protein band of the other GDH isoprotein, GDH I. When inhibition tests of the GDH isoproteins were performed with the seven anti-GDH II monoclonal antibodies, three antibodies inhibited GDH II activity, whereas only one antibody inhibited GDH I activity. The binding affinity of anti-GDH II monoclonal antibodies for GDH II (K(D) = 1.0 nM) determined using a biosensor technology (Pharmacia BIAcore) was fivefold higher than for GDH I (K(D) = 5.3 nM). These results, together with epitope mapping analysis, suggest that there may be structural differences between the two GDH isoproteins, in addition to their different biochemical properties. Using the anti-GDH II antibodies as probes, we also investigated the cross-reactivities of brain GDHs from some mammalian and an avian species, showing that the mammalian brain GDH enzymes are related immunologically to each other.

13-year survival comparison of percutaneous and open nephroureterectomy approaches for management of transitional cell carcinoma of renal collecting system: equivalent outcomes

BACKGROUND AND OBJECTIVE

Transitional cell carcinoma (TCC) of the renal collecting system traditionally has been managed by open nephroureterectomy with en bloc resection of a bladder cuff. However, for a select patient population with a solitary kidney or bilateral disease, the morbidity and mortality associated with chronic renal insufficiency and dialysis is deterring. In these situations, a more conservative approach such as antegrade percutaneous resection should be considered. The long-term disease-free outcome of percutaneous management in comparison with open nephroureterectomy has not been previously reported. We evaluated our experience with two surgical approaches to treat upper tract TCC: percutaneous resection and nephroureterectomy/nephrectomy to assess the clinical efficacy of these surgical modalities.

PATIENTS AND METHODS

We retrospectively identified 162 patients who had clinically localized TCC of the upper urinary tract. Records were reviewed to identify those with 13-year follow-up (N = 110) in respect to tumor grade, stage, disease-free status, length of cancer-specific survival, and overall survival. Statistical analysis of the results of open nephroureterectomy/nephrectomy (N = 60) and percutaneous resection (N = 50) was performed using Kaplan-Meier survival curves and Student's t-test.

RESULTS

All patients had disease in clinical stage Ta through T3. During a mean follow-up of 46.6 (range 6-150) months, grade 1 disease demonstrated little invasive potential. Of the disease-specific deaths, 60% (17/26) were of patients with grade 3 lesions, with a mean cancer survival period of 15.2 months after the initial procedure. Disease-specific survival rates after open and percutaneous approaches for grade 2 disease were 53.8 and 53.3 months, respectively (P > 0.05).

CONCLUSIONS

Tumor grade appeared to be the most important prognostic indicator in patients with renal TCC regardless of the surgical approach. Grade 3 tumors were more aggressive, presenting in an advanced stage with invasion, and recurrences were usually associated with metastasis. In this population, nephroureterectomy is warranted if the patient is a surgical candidate. The percutaneous option for grade 1 or 2 disease may be extended beyond the population with solitary kidneys and a risk of chronic renal failure to be offered to healthy individuals with normal contralateral kidneys who are willing to abide by a strict and lengthy follow-up.

Laparoscopic renal cryoablation: acute and long-term clinical, radiographic, and pathologic effects in an animal model and application in a clinical trial

OBJECTIVES

To evaluate renal cryosurgery by studying the feasibility of laparoscopic delivery and the radiographic characteristics and histopathologic effects in a porcine model using different freeze cycles. On the basis of the results, a clinical trial of laparoscopic cryosurgical ablation in select patients with clinical stage T1 renal tumors was started.

MATERIALS AND METHODS

Twelve kidneys from six farm pigs underwent cryosurgery. Each kidney was treated with two freeze cycles to -180 degrees C. Six kidneys were retroperitonealized, and six were not. An abdominal CT scan was performed at various times to evaluate for the presence of urinoma or hematoma and to monitor lesion changes. Organs were harvested at times ranging from 24 hours to 13 weeks. Radiographic and histopathologic changes were recorded for each time period. Eight patients with small (average 2-cm) exophytic renal masses underwent laparoscopic biopsy and cryosurgical ablation using a 3- or 4.8-mm probe (Cryomedical Sciences Inc., Rockville, MD) for one 15-minute or two 5-minute freeze cycles to a temperature of -180 degrees C to extend the ice ball at least 7 mm beyond the tumor margin.

RESULTS

Dense adhesions between the bowel and cryoablated renal tissue were encountered in all non-retroperitonealized kidneys, but no fistula formation was present. The retroperitonealized kidneys had minimal adhesion formation. None of the animals developed a urinary fistula. At 24 hours and 1 week, CT scanning demonstrated an enhancement defect corresponding to the region of the ice ball with no urinoma or hematoma. At 13 weeks, only a nonenhancing cortical defect was seen. At immediate harvest, hemorrhage was noted in the area of the ice ball with a sharp demarcation at the edge of the freeze zone. At 1 week, four distinct zones were seen: central necrosis, inflammatory infiltrate, hemorrhage, and fibrosis with regeneration. At 13 weeks, the necrotic tissue had been replaced with a circumscribed area of fibrosis. There were no intraoperative or postoperative complications in the eight patients. The estimated blood loss was 140 mL, and the mean hospital stay was 3.5 days. At a mean clinical follow-up of 7.7 (range 1-18) months and radiographic follow-up of 5 months; there have been no tumor recurrences or significant changes in the serum creatinine concentration. At 24 hours, there was an enhancement defect in the area of the ice ball. The CT images at 13 weeks showed a nonenhancing cortical defect in the area of the ice ball.

CONCLUSIONS

Cryosurgery can be readily delivered laparoscopically, creating a discrete lesion at the time of treatment that appears to be consistent over time. In the animal studies, complete tissue necrosis developed in the freeze zone, followed by reabsorption, and by 13 weeks, fibrous tissue had replaced the defect. In the animal and human trials, there were no operative complications, urinomas, hematomas, or bowel or urinary fistulas. Follow-up imaging in human trials revealed a persistent nonenhancing defect in the area of the freeze zone. Long-term clinical follow-up will be necessary to determine the cancer-free survival rate.

Chronic effect of pneumoperitoneum on renal histology

BACKGROUND AND OBJECTIVE

Transient intraoperative oliguria is a constant phenomenon during laparoscopic procedures. Laboratory studies have demonstrated that this effect is secondary to a decrease in renal blood flow caused by the pneumoperitoneum. With the advent of laparoscopic harvest of the kidney for renal transplantation, a concern is that increased intra-abdominal pressure may compound the effect of acute cold and warm renal ischemia during transplantation. Acute transient renal ischemia can produce chronic sclerosing histopathologic changes in native kidneys which are similar to those seen in chronic allograft rejection. The effect of positive-pressure abdominal pneumoperitoneum (15 mm Hg) on native kidneys was examined using a rodent model. The effects on renal function and histologic features were also studied.

MATERIALS AND METHODS

Twenty-four Harlan Wistar-Furth rats were divided into four groups: controls, 1-hour pneumoperitoneum-91-day survival, 5-hour pneumoperitoneum-91-day survival, and 5-hour pneumoperitoneum-7-day survival. Control animals underwent placement of the Veress needle and anesthesia but no induction of pneumoperitoneum. At the time of sacrifice, blood was sampled for serum creatinine measurement. Both kidneys were harvested for frozen and permanent section and stained using hematoxylin and eosin. Specimens were graded for inflammatory and ischemic/sclerotic changes in the interstitium, tubules, glomeruli, and vasculature by a renal pathologist using a histologic score (0-3).

RESULTS

In all groups, at a sacrifice interval of either 1 week or 3 months, there were no statistical differences in the histologic score, serum creatinine concentration, or renal weight.

CONCLUSIONS

In a rodent model, no signs of chronic ischemic histologic changes were detected for a period of 3 months after up to 5 hours of pneumoperitoneum. As well, there was no change in the serum creatinine concentration.

Hydrogen peroxide suppresses U937 cell death by two different mechanisms depending on its concentration

To investigate the mechanisms of H2O2 adaptation in mammalian cells, we exposed human U937 leukemia cells to 0.05 mM H2O2. This treatment significantly suppressed cell death and DNA fragmentation induced by a subsequent challenge with 1 mM H2O2. A more dramatic protection was observed when cells were pretreated with 0.25 mM H2O2. Pretreatment with either 0.05 or 0.25 mM H2O2 also imparted cells with a survival advantage against serum withdrawal and C2-ceramide treatment. H2O2 was found to be a mediator of cell death induced by serum withdrawal, but not by the addition of C2-ceramide. Interestingly, 0.25 mM H2O2 greatly induced glutathione peroxidase, a H2O2-consuming enzyme, whereas 0.05 mM H2O2 did not. Consistent with observation, pretreatment with 0.25 mM H2O2 resulted in a great reduction of cellular oxidant levels as determined by 2'7'-dichlorofluorescein fluorescence, and it also prevented elevation of oxidant levels upon subsequent challenge with 1 mM H2O2 or with serum withdrawal. These effects were not observed in cells pretreated with 0.05 mM H2O2. The sum of the data indicated that H2O2 suppresses cell death by two different mechanisms depending on its concentration: Relatively high concentrations enhance cellular antioxidant capacity, and lower concentrations block the lethal action of H2O2.

Clinical study of combined penetrating keratoplasty, pars plana vitrectomy with temporary keratoprosthesis, and pars plana seton implant

PURPOSE

To assess the effectiveness of a combined procedure (pars plana vitrectomy with temporary keratoprosthesis, penetrating keratoplasty, and pars plana seton implant) in preserving vision and controlling intraocular pressure (IOP).

METHODS

We reviewed the course of visual acuity, IOP, graft clarity, retinal status, and complications in 18 patients who underwent the above procedure during one operating sitting.

RESULTS

Preoperative diagnoses were varied. The majority of patients had pseudophakic bullous keratopathy and failed corneal transplants with glaucoma. Preoperative mean visual acuity was hand motions. Preoperative mean IOP was 27+/-13 mm Hg. Initially, all patients had attached retina. With a mean follow-up of 17+/-9 months, six patients had improved vision greater than 2 lines and 10 had unchanged vision. Only two patients lost vision greater than 2 lines. The final average IOP was 16+/-6 mm Hg and only one eye had a pressure above 22 mm Hg. Three eyes were classified as complete failures; two of the three became phthisical. Two patients developed rhegmatogenous detachments requiring further surgery.

CONCLUSION

The combined procedure offers reasonable improvement in vision, good pressure control, and a tolerable number of complications. It is a useful procedure in eyes that probably would not have been treatable otherwise.

Isolation and identification of succinic semialdehyde dehydrogenase inhibitory compound from the rhizome of Gastrodia elata Blume

In our search for the anticonvulsant constituent of Gastrodia elata repeated column chromatographies guided by activity assay led to isolation of an active compound, which was identified as gastrodin on the basis of spectral data. Brain succinic semialdehyde dehydrogenase (SSADH) was inactivated by preincubation with gastrodin in a time-dependent manner and the reaction was monitored by absorption and fluorescence spectroscopic methods. The inactivation followed pseudo-first-order kinetics with the second-rate order constant of 1.2 x 10(3) M-1min-1. The time course of the reaction was significantly affected by the coenzyme NAD+, which affected complete protection against the loss of the catalytic activity, whereas substrate succinic semialdehyde failed to prevent the inactivation of the enzyme. It is postulated that the gastrodin is able to elevate the neurotransmitter GABA levels in central nervous system by inhibitory action on one of the GABA degradative enzymes, SSADH.

Secure transmission of urologic images and records over the Internet

PURPOSE

Telemedicine has become a common method for the transmission of images and patient data across long distances. Our goal was to assess the efficiency and accuracy of Photomailer MD software, a store-and-forward telemedicine system, in the urologic setting.

METHODS

Photomailer MD software was loaded on two computers in the host institution, one with a T1 connection to the Internet and the other with a dial-up modem connection (24,000 bits/second), and computers at three remote sites. A total of 14 clinical cases, comprised of digitized histories and radiographic images, were sent to the remote institutions four separate times using the four transmission modes available: nonencrypted, 56-bit encryption, 128-bit encryption, and 128-bit encryption with password. The following data points were recorded: file size before and after encryption, file transmission times, and diagnostic accuracy of the remote urologists. One-way ANOVA was used to compare mean values statistically, while the z-test was used to compare diagnostic accuracies.

RESULTS

Encryption increased the file size by a mean of 37.8%, with the three encryption modes increasing file sizes by the same number of kilobytes. When a dial-up modem was used, encrypted files required a significantly longer transmission time (P < 0.05) than the unencrypted files. The same trend was seen with the T1 connection, although the differences often were not significant. When T1 transmission times were compared with modem times with other variables held constant, modem times were significantly longer (P < 0.05). Diagnostic accuracies for each of the three remote centers ranged from 85.7% to 100%. Differences in accuracy rates between attending physicians and residents were not significant.

CONCLUSIONS

Photomailer MD provides a secure, convenient, and affordable method of transmitting patient images and records via the Internet. Transmission speed was significantly greater when using a T1 line and also tended to be faster when files were not encrypted. There was no significant difference in transmission time among the three encryption modes; therefore, 128-bit encryption with a password should be used to maximize security. Diagnostic accuracies were comparable to those in the literature. In general, 640 x 480-pixel resolution was adequate for urologic diagnoses, although higher-resolution images may improve accuracy.

Ablation of renal tumors in a rabbit model with interstitial saline-augmented radiofrequency energy: preliminary report of a new technology

OBJECTIVES

To evaluate the efficacy of interstitial saline radiofrequency energy for reproducibly ablating nonmalignant (control) and malignant (the VX-2 tumor) renal tissue in a rabbit model, and to determine the ability of conventional gray-scale and power sonography to image the tumor and ablative process in real time before, during, and after treatment.

METHODS

The VX-2 tumor was implanted beneath the renal capsule in 18 rabbit kidneys. Twelve days after implantation, 50 W of 500-kHz radiofrequency energy was delivered into the surgically externalized renal tumor and contralateral control kidney for 30 or 45-second treatment intervals using an interstitial saline-augmented radiofrequency probe (the virtual electrode). Localization of the tumor and response to treatment were imaged with gray-scale and power Doppler ultrasonography. The effect of radiofrequency and extent of the destructive process on benign and malignant renal tissue were evaluated histologically.

RESULTS

Mean tumor size was 1.3 x 0.7 cm. Both 30 and 45-second treatment intervals provided marked tissue/tumor ablation. Gross anatomic and histologic analysis showed time-dependent ablated lesions averaging 1.4+/-0.3 x 1.0+/-0.3 cm (30-second treatment) and 1.8+/-0.4 x 1.5+/-0.3 cm (45-second treatment), with clear demarcation of the surrounding parenchyma. Conventional gray-scale sonography allowed visualization of the ablative process, and power Doppler ultrasound demonstrated changes in the vascular pattern of the tumor both before and after ablation. No immediate treatment-related complications were observed.

CONCLUSIONS

These preliminary studies in a rabbit model demonstrate the feasibility of using the interstitial saline-augmented electrode to ablate small renal tumors and the ability to simultaneously visualize the ablative process using real-time ultrasonography. This technology may have the potential to treat small renal tumors in a minimally invasive manner in the clinical setting.

Telemedicine and surgical robotics: urologic applications

Medical treatment can be improved through integration and application of advances in technology, computers, and engineering. Accuracy and reliability are essential characteristics of any mechanical system, and with the evolution of machines capable of precise movements, the integration of medicine and machine is achievable. Early mechanical devices were effective in performing simple, repetitive tasks but were not sophisticated enough for independent function. In the automobile industry, robots could work on the assembly line executing these cyclic tasks. These machines could execute simple, reiterative movements without integrating new information from the environment. In this day and age, robots have evolved into sophisticated mechanical devices that can "react" to data detected in the environment to determine the next course of events. They have evolved from the assembly line to the operating room, assisting surgeons during surgery to participating in remote telesurgical procedures.

Clinical decision making using teleradiology in urology

OBJECTIVE

Using a personal computer-based teleradiology system, we compared accuracy, confidence, and diagnostic ability in the interpretation of digitized radiographs to determine if teleradiology-imported studies convey sufficient information to make relevant clinical decisions involving urology. Variables of diagnostic accuracy, confidence, image quality, interpretation, and the impact of clinical decisions made after viewing digitized radiographs were compared with those of original radiographs.

MATERIALS AND METHODS

We evaluated 956 radiographs that included 94 IV pyelograms, four voiding cystourethrograms, and two nephrostograms. The radiographs were digitized and transferred over an Ethernet network to a remote personal computer-based viewing station. The digitized images were viewed by urologists and graded according to confidence in making a diagnosis, image quality, diagnostic difficulty, clinical management based on the image itself, and brief patient history. The hard-copy radiographs were then interpreted immediately afterward, and diagnostic decisions were reassessed. All analog radiographs were reviewed by an attending radiologist.

RESULTS

Ninety-seven percent of the decisions made from the digitized radiographs did not change after reviewing conventional radiographs of the same case. When comparing the variables of clinical confidence, quality of the film on the teleradiology system versus analog films, and diagnostic difficulty, we found no statistical difference (p > .05) between the two techniques. Overall accuracy in interpreting the digitized images on the teleradiology system was 88% by urologists compared with that of the attending radiologist's interpretation of the analog radiographs. However, urologists detected findings on five (5%) analog radiographs that had been previously unreported by the radiologist.

CONCLUSION

Viewing radiographs transmitted to a personal computer-based viewing station is an appropriate means of reviewing films with sufficient quality on which to base clinical decisions. Our focus was whether decisions made after viewing the transmitted radiographs would change after viewing the hard-copy images of the same case. In 97% of the cases, the decision did not change. In those cases in which management was altered, recommendation of further imaging studies was the most common factor.