Local Contrastive Learning for Medical Image Recognition

The proliferation of Deep Learning (DL)-based methods for radiographic image analysis has created a great demand for expert-labeled radiology data. Recent self-supervised frameworks have alleviated the need for expert labeling by obtaining supervision from associated radiology reports. These frameworks, however, struggle to distinguish the subtle differences between different pathologies in medical images. Additionally, many of them do not provide interpretation between image regions and text, making it difficult for radiologists to assess model predictions. In this work, we propose Local Region Contrastive Learning (LRCLR), a flexible fine-tuning framework that adds layers for significant image region selection as well as cross-modality interaction. Our results on an external validation set of chest x-rays suggest that LRCLR identifies significant local image regions and provides meaningful interpretation against radiology text while improving zero-shot performance on several chest x-ray medical findings.

Varicella Zoster Associated Vasculopathy and Retinitis with Natalizumab Use in Multiple Sclerosis

Natalizumab (Tysabri®, NTZ) is a monoclonal autoantibody approved for treatment of relapsing-remitting multiple sclerosis. NTZ inhibits leukocyte migration across the blood-brain barrier, preventing autoreactive cells from inciting an inflammatory immune response. This immunosuppression is highly efficacious in attenuating the risk of relapse of disease, but has been associated with opportunistic central nervous system (CNS) infections, most notably progressive multifocal leukoencephalopathy. Varicella-zoster and herpes simplex viruses have also been associated with NTZ, inciting a spectrum of disease, including encephalitis, meningitis, and acute retinal necrosis. While rare, these infections can result in devastating outcomes even when promptly identified and treated.   We present a case of combined CNS varicella zoster vasculitis and acute retinal necrosis in a 57-year-old woman maintained on monthly Natalizumab therapy, who presented with headache and visual field deficits.

MO078DEEP LEARNING DIAGNOSIS OF ANTIBODY-MEDIATED REJECTION (AMR) ON GLOMERULAR TRANSECTIONS

Background and Aims

Antibody-mediated rejection (AMR) is among the most common causes for kidney transplant loss. The histological diagnosis is hampered by significant intra- and interobserver variability. Training a deep learning classifier for the recognition of AMR on glomerular transections as the most decisive compartment could establish a reliable and perfectly reproducible diagnostic method.

Method

We identified 48 biopsies with AMR (all positive for donor-specific antibody) and 38 biopsies without AMR according to Banff 2017 from our archive. Photographs were taken from all non-globally sclerosed glomeruli on two PAS-stained level sections, yielding a total of 1,655 images as a training set. 1,503 images could be labeled by three experienced nephropathologists conclusively as AMR or non-AMR in a blinded fashion. We trained a DenseNet-121 classifier (pre-trained on ImageNet) with basic online augmentation. In addition, we implemented StyPath++, a data augmentation algorithm that leverages a style transfer mechanism, addressing significant domain shifts in histopathology. Each sample was assigned a consensus label generated by the pathologists.

Results

Five-fold cross validation schemes produced a weighted glomerular level performance of 88.1%, exceeding the baseline performance by 5%. The improved generalization ability of the StyPath++ augmented model shows that it is possible to construct reliable glomerular classification algorithms with scarce datasets.

Conclusion

We created a deep learning classifier with excellent performance and reproducibility for the diagnosis of AMR on glomerular transections. We plan to expand the training set, including challenging cases of differential diagnoses like glomerulonephritis or other glomerulopathies. We are also interested in external clinicopathological datasets to further validate our results.

A Randomized Controlled Pilot Trial to Test the Efficacy of Intranasal Chlorpheniramine Maleate With Xylitol for the Treatment of Allergic Rhinitis

The prevalence of allergic rhinitis (AR), including symptoms of sneezing, nasal itching, airflow obstruction, and nasal discharge caused by histamine and immunoglobulin E (IgE)-mediated reactions, is ~30% in the U.S. Recent studies seem to suggest that the allergic inflammatory processes in AR may be induced by the interaction between an allergen (trigger) and the nasal microbiome (substrate). In this study, we have identified two agents with antihistaminic and microbiome-modulating characteristics that can be administered intranasally, namely, chlorpheniramine maleate (CPM) and xylitol (X). This study aimed to test the efficacy of intranasal CPM plus xylitol (CPM+X) nasal for the treatment of AR in an outpatient setting. A multicenter, randomized, double-blind, 30-day pilot study was conducted during the spring of 2019. After starting five days of placebo therapy (run-in period), patients with moderate-to-severe AR nasal symptoms were randomized to treatment with CPM+X (n=16) spray and nasal saline placebo (PLB; n=13). Both treatments were administered in the form of one spray dose (~100 µL of the solution containing 1.25 mg CPM) per nostril twice a day. Outcome variables were the changes in visual analog scale (VAS) and daily symptoms score (DSS) at days 1, 5, 10, 15, 25, and 30 after the initiation of the treatment. ANOVA (analysis of variance) with repeated revealed a significant treatment-by-time interaction such that the CPM+X group had a significant decrease (p < 0.05) in both DSS (∆-3.0 ± 2.7) and VAS (∆-3.8 ± 2.0) scores compared to PLB after 30 days. The difference in DSS and VAS scores between the groups was evident just after five days (day 10) of using CPM+X. The CPM+X scores were significantly lower (p < 0.008) starting from day 10 compared with day 1, whereas there were no statistically significant (p > 0.008) changes in the PLB during the 30-day treatment window. The present data suggest that nasal CPM+X use effectively improves AR symptoms. A large-scale study of the long-term effects of CPM+X for the treatment of other chronic respiratory disorders and the potential microbiome-modulating effects warrants further investigation.

Multiple sclerosis relapse presenting as an acute cardiomyopathy

Multiple sclerosis is increasingly being recognized in association with cardiovascular dysfunction, which can manifest with cardiomyopathy, pulmonary edema (Kaplan et al., 2015), orthostasis (Kaplan et al., 2015) and other complications. Takotsubo cardiomyopathy is a syndrome of acute-onset ventricular dysfunction in the absence of obstructive coronary artery disease, which on rare occasion has been observed in the setting of demyelinated plaques in the brainstem. We report on two cases of Takotsubo cardiomyopathy with medullary demyelination secondary to multiple sclerosis.

Protective effect of metoclopramide against organophosphate-induced apoptosis in the murine skin fibroblast L929

This study was performed to evaluate the protective efficacy of metoclopramide (MCP) against the organophosphates paraoxon (POX)- and malathion (MLT)-induced apoptosis in the murine L929 skin fibroblasts. L929 cells were exposed to either POX (10 nm) or 1.0 μm MLT in the absence and presence of increased concentrations of MCP. The protective effect of MCP on these organophosphate-stimulated apoptotic events was evaluated by flow cytometry analysis after staining with annexin-V/propidium iodide, processing and activation of the executioner caspase-3, cleavage of the poly-ADP ribose polymerase, fragmentation of the nucleosomal DNA and disruption of the mitochondrial membrane potential (Δψ). Our results showed that increased doses of MCP alone (≥10 μm) did not induce apoptosis or activation of caspase-3. Pretreatment of the cells with MCP attenuated all the apoptotic events triggered by the organophosphate compounds in a dose-dependent manner reaching ~70-80% protection when they were preincubated at 1 and 5 μm of the drug before the addition of POX and MLT, respectively. Interestingly, MCP did not offer a significant protective effect against the cytotoxicity of tumor necrosis factor-α, cisplatinum, etoposide or paclitaxel, which stimulate apoptosis by various mechanisms, suggesting that the anti-apoptotic effect of the drug is specific to organophosphates. The strong and specific anti-apoptotic activity of subclinical doses of MCP against the cytotoxicity of organophosphate compounds suggests its potential clinical application in treating their poisoning.

Composition, Antioxidant, and Cytotoxic Activities of the Essential Oils from Fresh and Air-Dried Aerial Parts of Pallenis spinosa

This study was performed to determine the chemical composition, antioxidant and cytotoxic effects of essential oils extracted from the aerial parts of fresh (F-PSEO) and air-dried (D-PSEO) Pallenis spinosa. The composition of the oils was analyzed by gas chromatography (GC) and GC/mass spectrometry, the antioxidant activity by free radical scavenging and metal chelating assays, and their cytotoxicity by a flow cytometry analysis. The primary components in both oils were sesquiterpene hydrocarbons and oxygentated sesquiterpenes. F-PSEO contained 36 different compounds; α-cadinol (16.48%), germacra-1(10),5-diene-3,4-diol (14.45%), γ-cadinene (12.03%), and α-muurolol (9.89%) were the principal components. D-PSEO contained 53 molecules; α-cadinol (19.26%), δ-cadinene (13.93%), α-muurolol (12.88%), and germacra-1(10),5-diene-3,4-diol (8.41%) constituted the highest percentages. Although both oils exhibited a weak radical scavenging and chelating activity, compared to α-tocopherol and ascorbic acid, D-PSEO showed a 2-fold greater antioxidant activity than F-PSEO. Furthermore, low doses of F-PSEO were able to inhibit the growth of leukemic (HL-60, K562, and Jurkat) and solid tumor cells (MCF-7, HepG2, HT-1080, and Caco-2) with an IC₅₀ range of 0.25 - 0.66 μg/ml and 0.50 - 2.35 μg/ml, respectively. F-PSEO showed a ca. 2 - 3-fold stronger cytotoxicity against the tested cells than D-PSEO. The potent growth inhibitory effect of the plant essential oil encourages further studies to characterize the molecular mechanisms of its cytotoxicity.

Plasma Osteopontin Levels and Adverse Cardiovascular Outcomes in the PEACE Trial

Osteopontin (OPN) is a secreted glycophosphoprotein that has a role in inflammation, immune response and calcification. We hypothesized that plasma OPN levels are associated with adverse cardiovascular outcomes in patients with stable coronary artery disease (CAD) and preserved ejection fraction (EF) enrolled in the PEACE trial. We measured plasma OPN levels at baseline in 3567 CAD patients (mean age 64.5 ± 8.1 years, 81% men) by a sandwich chemiluminescent assay (coefficient of variation = 4.1%). OPN levels were natural log (Ln) transformed prior to analyses. We assessed whether Ln OPN levels were associated with the composite primary endpoint of cardiovascular death, non-fatal myocardial infarction and hospitalization for heart failure using multiple event multivariable Cox proportional hazards regression. Adjustment was performed for: (a) age and sex; (b) additional potential confounders; and (c) a parsimonious set of statistically significant 10 variates. During a median follow-up of 4.8 years, 416 adverse cardiovascular outcomes occurred in 366 patients. Ln OPN was significantly associated with the primary endpoint; HR (95% CI) = 1.56 (1.27, 1.92); P <0.001, and remained significant after adjustment for age and sex [1.31 (1.06, 1.61); P = 0.01] and after adjustment for relevant covariates [1.24 (1.01, 1.52); P = 0.04]. In a secondary analysis of the individual event types, Ln OPN was significantly associated with incident hospitalization for heart failure: HR (95% CI) = 2.04 (1.44, 2.89); P <0.001, even after adjustment for age, sex and additional relevant covariates. In conclusion, in patients with stable CAD and preserved EF on optimal medical therapy, plasma OPN levels were independently associated with the composite incident endpoint of adverse cardiovascular outcomes as well as incident hospitalization for heart failure.

Outpatient ambulatory EEG as an option for epilepsy surgery evaluation instead of inpatient EEG telemetry

Outpatient ambulatory EEG is more cost-effective than inpatient EEG telemetry and may provide adequate seizure localization in a presurgical evaluation. A 51-year-old right-handed male had been unable to work or drive since the age of 35 due to intractable partial onset epilepsy. A 72-hour outpatient ambulatory EEG recorded 18 seizures from the right temporal region. No epileptiform activity was seen in the left hemisphere. Magnetic resonance imaging showed right mesial temporal sclerosis as well as an area of encephalomalacia at the medial inferior right temporal lobe. Neuropsychological assessment found that the patient was a good neurosurgery candidate. At this point, the patient was considered to be a candidate for a right temporal lobectomy. A standard right temporal lobectomy was performed. The patient has been seizure-free for 10 months after the surgery. Follow-up EEGs show no epileptiform activity. The patient is preparing to go back to work, and his driver's license was reinstated 9 months postsurgery. Neuropsychological reassessment is pending, but no apparent change in cognition has been noticed by the patient or his family. Cases with a high congruence between diagnostic imaging and the EEG abnormalities identified in the portable EEG may provide enough information regarding seizure frequency and localization to eliminate the need for inpatient EEG telemetry in the evaluation of patients for epilepsy surgery. We believe that the use of aEEG in preoperative planning should be restricted to cases of TLE and to patients with a high frequency of seizures.

Open surgical management of pediatric urolithiasis: A developing country perspective

Objectives

To describe decision factors and outcome of open surgical procedures in the management of children with stone.

Materials and Methods

Between January 2004 and December 2008, 3969 surgical procedures were performed in 3053 children with stone disease. Procedures employed included minimally invasive techniques shockwave lithotripsy (SWL), percutaneous nephrolithotomy (PCNL), ureterorenoscopy (URS), perurethral cystolithotripsy (PUCL), percutaneous cystolithotripsy (PCCL), and open surgery. From sociomedical records demographics, clinical history, operative procedures, complications, and outcome were recorded for all patients.

Results

Of 3969 surgeries, 2794 (70%) were minimally invasive surgery (MIS) techniques to include SWL 19%, PCNL 16%, URS 18.9%, and PUCL+PCCL 16% and 1175 (30%) were open surgeries. The main factors necessitating open surgery were large stone burden 37%, anatomical abnormalities 16%, stones with renal failure 34%, gross hydronephrosis with thin cortex 58%, urinary tract infection (UTI) 25%, and failed MIS 18%. Nearly 50% of the surgeries were necessitated by economic constraints and long distance from center where one-time treatment was preferred by the patient. Stone-free rates by open surgeries were pyelolithotomy 91%, ureterolithotomy 100%, and cystolithotomy 100% with complication rate of upto 3%.

Conclusions

In developing countries, large stone burden, neglected stones with renal failure, paucity of urological facilities, residence of poor patients away from tertiary centers necessitate open surgical procedures as the therapy of choice in about 1/3rd of the patients. Open surgery provides comparable success rates to MIS although the burden and nature of disease is more complex. The scope of open surgery will remain much wide for a large population for considered time in developing countries.

Identification and characterization of a small molecule inhibitor of formin-mediated actin assembly

Formins stimulate actin filament assembly for fundamental cellular processes including division, adhesion, establishing polarity, and motility. A formin inhibitor would be useful because most cells express multiple formins whose functions are not known and because metastatic tumor formation depends on the deregulation of formin-dependent processes. We identified a general small molecule inhibitor of formin homology 2 domains (SMIFH2) by screening compounds for the ability to prevent formin-mediated actin assembly in vitro. SMIFH2 targets formins from evolutionarily diverse organisms including yeast, nematode worm, and mice, with a half-maximal inhibitor concentration of approximately 5 to 15 microM. SMIFH2 prevents both formin nucleation and processive barbed end elongation and decreases formin's affinity for the barbed end. Furthermore, low micromolar concentrations of SMIFH2 disrupt formin-dependent, but not Arp2/3 complex-dependent, actin cytoskeletal structures in fission yeast and mammalian NIH 3T3 fibroblasts.

Maternal risk factors associated with low birth weight in Karachi: a case-control study

To evaluate maternal risk factors associated with low birth weight (LBW) among women aged 15-35 years, we carried out a hospital-based, case-control study on 262 cases (mothers of neonates weighing < or = 2.5 kg) and 262 controls (mothers of neonates weighing > 2.5 kg). Odds of delivering a low-birth-weight baby decreased with increase in maternal haemoglobin [odds ratio (OR): 0.701; 95% confidence interval (CI): 0.62-0.79]. Odds were greater among mothers not using iron supplements during pregnancy (OR: 2.88; 95% CI: 1.83-4.54). Mothers of LBW babies had lower haemoglobin levels before delivery.

Glatiramer in the treatment of multiple sclerosis

Multiple sclerosis (MS) is a disease of the central nervous system with both an inflammatory and degenerative component. The disease primarily affects young adults and results in significant physical and cognitive disability. Several disease-modifying agents are currently used in the management of multiple sclerosis. Glatiramer acetate (GA, Copaxone, co-polymer 1) is a disease-modifying agent approved for the treatment of relapsing remitting multiple sclerosis. Apart from its unique mode of action, there is evidence pointing toward a possible neuroprotective role. This review will critically discuss GA's potential mechanisms of action, the results of clinical trials, safety profile, and future directions of treatment.

Thirty-one years of clinical experience with "nuclear-powered" pacemakers

From 1973 through 1987, 164 radioisotope powered ("nuclear") pacemakers were implanted in 139 patients at the Newark Beth Israel Medical Center. Patient survival was much as might be expected from an age group as selected for this program. At 31 years (January 2005), 12 of the 139 patients (9%) were still alive. The experience reported here encompassed a span of 16 years of implantation with a follow-up of slightly more than 31 years. The problems encountered along the way were not remarkably different from those encountered in general clinical experience with pacemakers, except that the number of reoperations was fewer. In fact, most patients died with the initial implant in place. Deaths most commonly were due to cardiac causes (54%). The frequency of malignancies was similar to that of the age-matched population; primary tumor sites were randomly distributed. These results show that nuclear pacemakers were safe and reliable. Their longevity and the resulting decrease in reoperations offset their greater initial cost.

Cryoetch and Cryo-planing for Low Temperature HRSEM SE-I Imaging of Hydrated Multicellular Microbial and Bioorganic Systems

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

Mitoxantrone for multiple sclerosis in clinical practice

Patients with worsening relapsing-remitting multiple sclerosis (MS), secondary progressive MS, and progressive relapsing MS are potential candidates for treatment with mitoxantrone. Early identification of these patients is essential because there is emerging evidence that early and aggressive treatment might delay or limit long-term disability. Treatment with mitoxantrone is associated with certain adverse events, such as cardiotoxicity. However, the possible benefits of treatment (e.g., reduction in disease progression) outweigh the risks for patients with aggressive or worsening disease. With the selection of appropriate patients and careful monitoring for adverse events, mitoxantrone can be safely administered.

Other therapy options and future strategies for treating patients with multiple sclerosis

Research into therapy for multiple sclerosis (MS) is occurring at a rapid pace, and current treatment options approved by the FDA specifically target the inflammatory phase of MS. However, drugs that are not FDA-approved are routinely used to treat MS. One example is corticosteroids, which are commonly used to treat acute relapses. Other drugs that are commonly used to treat patients who do not respond to the FDA-approved agents include the following: methotrexate, azathioprine, cyclophosphamide, and pulse steroids. Drugs being studied as possible therapeutic agents include the statins, mycophenolate mofetil, various monoclonal antibodies (e.g., alemtuzumab, daclzumab, natalizumab, and rituximab), antibiotics and antivirals, and the pregnancy hormone estriol. Disease modifying agents (DMAs) that promote remyelination would be beneficial for preventing long-term disability, and such agents are also under active investigation (e.g., IV immunoglobulin G and stem cell transplantation). Combination therapy with DMAs with different mechanisms of action may be advantageous in the future for providing optimal treatment that both delays the progression of disability and promotes repair and remyelination.

Current approved options for treating patients with multiple sclerosis

Multiple sclerosis (MS), a neurologic disorder that affects 400,000 persons in the United States, consists of an inflammatory and a neurodegenerative phase. Treatment options now approved by the FDA specifically target the inflammatory phase of MS and include immunomodulators (i.e., interferon betas and glatiramer acetate) and an immunosuppressant, mitoxantrone. This article discusses the methods of monitoring disease progression using disability scales and MRI and reviews the clinical efficacy and tolerability of the FDA-approved therapies. All of the immunomodulators are approved for the treatment of relapsing forms of MS. Only mitoxantrone is approved for the treatment of worsening relapsing-remitting MS, secondary progressive MS, and progressive-relapsing MS. Early treatment with these disease-modifying agents is desirable to reduce the progression of the disease and to limit long-term disability.

Identifying and treating patients with suboptimal responses

Multiple sclerosis (MS) is an immune-mediated neurologic disease in which acute inflammatory events early in the disease course contribute to subsequent neurologic disability. The early relapsing inflammatory phase is followed by a progressive degenerative phase in which the frequency of acute inflammatory attacks diminishes but progressive loss of neurologic function continues. Current immune therapies are most effective in suppressing the acute inflammatory events that characterize the earlier stages of disease. Optimal suppression of these inflammatory events is likely to have the best potential for delaying or preventing loss of axons and decline in neurologic function. In view of these considerations, and because MS is a heterogeneous disease and response to disease-modifying agents (DMA) varies across individuals, it is important to identify suboptimal responders as early as possible to allow therapeutic modification while the opportunity to avert future loss of function remains. At present, no criteria for identifying suboptimal responders have been validated. In January 2004, a group of neurologists from 16 MS centers in the United States met to develop a consensus on criteria for defining suboptimal response for use in compelling clinical situations and to prompt clinical studies to validate the efficacy of these criteria. Consensus criteria included relapse rates of either 1/year or unchanged from pretreatment rates, incomplete recovery from multiple attacks, evolution of polyregional neurologic involvement, recurrent brainstem or spinal cord lesions, and cumulative loss of neurologic function sufficient to disrupt daily activities. The panel then considered the use of mitoxantrone for patients with worsening MS and a suboptimal response to DMA therapy.

Management of pediatric urolithiasis in Pakistan: experience with 1,440 children

PURPOSE

We evaluated the efficacy and safety of different modalities for pediatric urolithiasis in a developing country in 2 eras, namely before and after the advent of minimally invasive surgery.

MATERIALS AND METHODS

We retrospectively reviewed the records of 1,440 children younger than 14 years treated with various modalities during a 14-year period. From 1987 to 1995, 486 and 50 patients were treated with open surgery, and extracorporeal shock wave lithotripsy (ESWL, Dornier Medical Systems, Inc., Marietta, Georgia) and minimally invasive methods, respectively. Between 1996 and 2000, 518 and 386 children were treated with surgery and minimally invasive methods, respectively.

RESULTS

Of the 1,440 children 795 (55.2%) had renal, 198 (13.8%) had ureteral and 447 (31%) had bladder calculi. Of the renal stones 556 (70%), 177 (22%) and 62 (7.8%) were treated with open surgery, ESWL and percutaneous nephrolithotomy, respectively. Of the ureteral calculi 85 (43%), 37 (18.6%) and 76 (38%) were managed by ESWL, ureterorenoscopy and open surgery, respectively. Of the bladder calculi 307 (68%), 77 (17.2%) and 63 (14%) were treated with open vesicolithotomy, transurethral pneumatic cystolithotripsy and ESWL, respectively. The renal stone clearance rate was 98% after open surgery, 84% after ESWL and 68% after percutaneous nephrolithotomy monotherapy at 3 months of followup. Similarly the ureteral stone-free rate was 54% after ESWL and 86.9% after ureterorenoscopy. Of the patients with bladder calculi 48% and 93% become stone-free after ESWL and transurethral pneumatic cystolithotripsy, respectively.

CONCLUSIONS

The use of ESWL, percutaneous nephrolithotomy and ureterorenoscopy has resulted in treating a large number of children with a short hospital stay and early return to school. Open surgery is reserved only for complex stones.

Symptomatic therapy for underrecognized manifestations of multiple sclerosis

The symptoms that affect individuals with MS are diverse and change over time. Addressing symptoms in a multidisciplinary fashion and helping patients address problems as they occur are the major elements of symptom management. Successful management involves treating not only the more readily recognized manifestations of MS but also the less apparent MS features, including fatigue, cognitive loss, mood disturbance, and pain. Management of these symptoms is reviewed.

Laser extraction of entrapped leads

Removing entrapped pacing and defibrillator leads has been greatly simplified by making use of the excimer laser extractor. Sixty-two leads were successfully removed, although where appropriate, portions of the lead remained in place in 10 cases. There were two serious complications, one tear of the superior vena cava during an ICD extraction and one tear of the atrium during an atrial lead extraction. Both were controlled successfully through emergency sternotomy. Although extracting entrapped leads has been much simplified by making use of the laser extractor, the process is not free of serious complications. Those involved in explanting leads should be aware of the outcomes and be prepared for emergent management.

High-energy microwave thermotherapy in patients in urinary retention

PURPOSE

To study the outcome of high-energy transurethral microwave thermotherapy (TUMT) in patients with obstructive benign prostatic hyperplasia (BPH).

PATIENT AND METHODS

Between September 1995 and March 1998, patients presenting with urinary retention secondary to BPH were recruited into the study. Their mean age was 67.2 years (range 50-85 years). The mean catheterization time prior to treatment was 3 months (range 15 days-1 year). Among the 200 patients treated during this period, 30 were high anesthesia risk (American Society of Anesthesiologists Class III/IV). The patients were treated in a single 1-hour session using high-energy (Prostatron 2.5) software, the range of energy transmitted being 111.9 to 214.2 kJ (mean 196.3 kJ). Symptoms were scored according to the International Prostatic Symptom Score (IPSS). The mean prostate volume subjected to TUMT was 59 cc (range 40-149.7 cc). The patients were followed every 3 months with measurements of peak flow rate, postvoiding residual urine volume estimation, and IPSS.

RESULTS

Of the 200 patients, 33 were lost to follow-up, 155 were responsive (catheter free with physiologically acceptable peak flow rate), and 12 (7%) were nonresponsive. Only 4 patients (2%) experienced deterioration in their flow rates during the follow-up period of 2 years. They underwent transurethral resection. High-energy thermotherapy resulted in irritative voiding complaints in 80% of patients for 2 to 4 weeks.

CONCLUSION

The initial results were encouraging, and the 2-year follow-up has shown appreciable sustainability in the treatment outcome, particularly in patients at high anesthesia risk.

[The use of transpedicular system of stabilization in surgical treatment of vertebral column tumors]

The experience of application of the titanium transpedicular systems in 23 patients with the vertebral column (VC) tumor was summarized. In all the patients good VC stability was noted after the operation, what had permitted to conduct their early activization.

Outcome of machine-perfused non-heart-beating donor kidneys, not allocated within the Eurotransplant area

Eleven non-heart-beating (NHB) donor kidneys considered vital during machine perfusion (MP), could not be allocated inside Eurotransplant (ET). With the help of ET, five kidneys were transplanted in Karachi and six in Basel. Our goal was to prove that NHB kidneys successfully passing MP viability tests can be transplanted safely.

METHODS

Donor age, serum creatinine (some post-mortem) and warm ischaemic time were, respectively, (mean and range): 44 (14-70) years, 137 mumol/l, and 44 (9-80) min. Reasons for refusal were: bold ureter (one), suboptimal flush (one), relatively long hypotensive phase (seven), and donor age of 70 years (two). After 8 h of MP, mean lactate dehydrogenase, intrarenal resistance and alpha glutathione S-transferase were (including range): 556 U/l (range 366-819 U/l), 0.86 mmHg/ml per min (0.41-1.15 mmHg/ml per min) and 1188 micrograms/l (575-2677 micrograms/l), respectively. Mean cold ischaemic time was 45 (range 28-72) h.

RESULTS

Two kidneys showed immediate function, and nine showed delayed function. Mean creatinine levels after 1, 3 and 6 months were 295, 200 and 206 mumol/l, respectively. Four patients died for reasons not related to their kidney transplantation.

CONCLUSIONS

We claim that MP can successfully assess viability of NHB donor kidneys. The reluctance to accept MP, and judged vital, NHB donor kidneys is not longer justified.

A modular neural network vector predictor for predictive image coding

In this paper, we present a modular neural network vector predictor that improves the predictive component of a predictive vector quantization (PVQ) scheme. The proposed vector prediction technique consists of five dedicated predictors (experts), where each expert predictor is optimized for a particular class of input vectors. An input vector is classified into one of five classes, based on its directional variances. One expert predictor is optimized for stationary blocks, and each of the other four expert predictors are optimized to predict horizontal, vertical, 45 degrees , and 135 degrees diagonally oriented edge-blocks, respectively. An integrating unit is then used to select or combine the outputs of the experts in order to form the final output of the modular network. Therefore, no side information is transmitted to the receiver about the selected predictor or the integration of the predictors. Experimental results show that the proposed scheme gives an improvement of 1.7 dB over a single multilayer perceptron (MLP) predictor. Furthermore, if the information about the predictor selection is sent to the receiver, the improvement could be up to 3 dB over a single MLP predictor. The perceptual quality of the predicted images is also significantly improved.

Prediction of renal function recovery in obstructive renal failure due to stones

Two hundred and thirty-nine patients with renal and ureteric calculi associated with renal failure were evaluated for recovery potential before definitive surgery. Ultrasonography was carried out pre-operatively in all, followed by percutaneous nephrostomy (PCN) as an initial management before definitive surgery. Diethylene triamine penta acetic acid (DTPA) scan was done in 125 patients after percutaneous nephrostomy, findings of pre- operative DTPA scan were correlated with post-operative drop in serum creatinine. Urine pH, urine Na+, initial diuresis, creatinine clearance and serum creatinine were measured serially after 24 hours and then every week for 6 weeks. Patients were re-evaluated with serum creatinine after 3 months of surgery. Ultrasonography was found to be reliable in predicting future recovery of renal functions in 76.5% cases and true obstruction of shorter duration (F4-group) on DTPA scan in 81.9% cases. Urine pH of 6 or less, post-PCN diuresis and natriuresis were good prognostic indicators. PCN was found to be most reliable method of predicting future recovery of renal function after relief of obstruction with 97.8% accuracy.

Nonlinear vector prediction using feed-forward neural networks

The performance of a classical linear vector predictor is limited by its ability to exploit only the linear correlation between the blocks. However, a nonlinear predictor exploits the higher order correlations among the neighboring blocks, and can predict edge blocks with increased accuracy. We have investigated several neural network architectures that can be used to implement a nonlinear vector predictor, including the multilayer perceptron (MLP), the functional link (FL) network, and the radial basis function (RBF) network. Our experimental results show that a neural network predictor can predict the blocks containing edges with a higher accuracy than a linear predictor.