Synthetic Megavoltage Cone Beam Computed Tomography Image Generation for Improved Contouring Accuracy of Cardiac Pacemakers

In this study, we aimed to enhance the contouring accuracy of cardiac pacemakers by improving their visualization using deep learning models to predict MV CBCT images based on kV CT or CBCT images. Ten pacemakers and four thorax phantoms were included, creating a total of 35 combinations. Each combination was imaged on a Varian Halcyon (kV/MV CBCT images) and Siemens SOMATOM CT scanner (kV CT images). Two generative adversarial network (GAN)-based models, cycleGAN and conditional GAN (cGAN), were trained to generate synthetic MV (sMV) CBCT images from kV CT/CBCT images using twenty-eight datasets (80%). The pacemakers in the sMV CBCT images and original MV CBCT images were manually delineated and reviewed by three users. The Dice similarity coefficient (DSC), 95% Hausdorff distance (HD95), and mean surface distance (MSD) were used to compare contour accuracy. Visual inspection showed the improved visualization of pacemakers on sMV CBCT images compared to original kV CT/CBCT images. Moreover, cGAN demonstrated superior performance in enhancing pacemaker visualization compared to cycleGAN. The mean DSC, HD95, and MSD for contours on sMV CBCT images generated from kV CT/CBCT images were 0.91 ± 0.02/0.92 ± 0.01, 1.38 ± 0.31 mm/1.18 ± 0.20 mm, and 0.42 ± 0.07 mm/0.36 ± 0.06 mm using the cGAN model. Deep learning-based methods, specifically cycleGAN and cGAN, can effectively enhance the visualization of pacemakers in thorax kV CT/CBCT images, therefore improving the contouring precision of these devices.

Trigger related outcomes of takotsubo syndrome in a cancer population

Background

Takotsubo syndrome (TTS) occurs more frequently in cancer patients than in the general population, but the effect of specific TTS triggers on outcomes in cancer patients is not well studied.

Objectives

The study sought to determine whether triggering event (chemotherapy, immune-modulators vs. procedural or emotional stress) modifies outcomes in a cancer patient population with TTS.

Methods

All cancer patients presenting with acute coronary syndrome (ACS) between December 2008 and December 2020 at our institution were enrolled in the catheterization laboratory registry. Demographic and clinical data of the identified patients with TTS were retrospective collected and further classified according to the TTS trigger. The groups were compared with regards to major adverse cardiac events, overall survival and recovery of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) after TTS presentation.

Results

Eighty one of the 373 cancer patients who presented with ACS met the Mayo criteria for TTS. The triggering event was determined to be "cancer specific triggers" (use of chemotherapy in 23, immunomodulators use in 7, and radiation in 4), and "traditional triggers" (medical triggers 22, and procedural 18 and emotional stress in 7). Of the 81 patients, 47 died, all from cancer-related causes (no cardiovascular mortality). Median survival was 11.9 months. Immunomodulator (IM) related TTS and radiation related TTS were associated with higher mortality during the follow-up. Patients with medical triggers showed the least recovery in LVEF and GLS while patients with emotional and chemotherapy triggers, showed the most improvement in LVEF and GLS, respectively.

Conclusion

Cancer patients presenting with ACS picture have a high prevalence of TTS due to presence of traditional and cancer specific triggers. Survival and improvement in left ventricular systolic function seem to be related to the initial trigger for TTS.

Survey of Anesthesia, Sedation, and Non-sedation Practices for Children Undergoing Repetitive Cranial or Craniospinal Radiotherapy

Background

Children undergoing cranial or craniospinal radiotherapy may require over 30 treatments within a six-week period. Facilitating these many treatments with the patient under anesthesia presents a significant challenge, and the most preferred anesthetic methods remain unknown. The primary goal of this study was to determine the most preferred anesthetic methods and agents for children undergoing daily cranial or craniospinal radiotherapy.

Methods

An 83-item web-based survey was developed. An introductory email was sent to 505 physicians and child-life specialists with expertise in pediatric anesthesia and/or affiliated with pediatric radiation oncology departments.

Results

The response rate was 128/505 (25%) and included specialists from Africa (5, 4%), Asia (18, 14%), Australia/Oceania (5, 4%), Europe (45, 35%), North America (50, 39%), and South America (5, 4%). The 128 respondents included 91 anesthesiologists (71%), 20 physicians who were not anesthesiologists (16%), 14 child life/social education specialists (11%), one radiotherapist, one pediatric radiation nurse, and one non-specified medical professional (all = 2%). Of the 128 respondents, 95 (74%) used anesthesia or sedation to facilitate repetitive cranial or craniospinal radiotherapy. Overall, total intravenous anesthesia without intubation was preferred by 67 of 95 (71%) specialists during one or more forms of radiotherapy. During photon-based radiotherapy, total intravenous anesthesia without intubation was the preferred anesthetic method with the patient in the supine (57/84, 68%) and prone positions (25/40, 63%). Propofol was the most used anesthetic agent for both supine (73/84, 87%) and prone positions (38/40, 95%). For proton radiotherapy, total intravenous anesthesia without intubation was the most preferred anesthetic method for the supine (32/42, 76%) and prone treatment positions (11/18, 61%), and propofol was the most used anesthetic (supine: 40/43, 93%; prone: 16/18, 89%).

Conclusions

In this survey of 95 specialists responsible for anesthesia or sedation of children undergoing repetitive cranial or craniospinal radiotherapy, propofol-based total intravenous anesthesia without intubation was the preferred anesthetic technique.

A retrospective evaluation of the impact of patient ethnicity on the use of epidural analgesia or blood transfusions in children undergoing major oncologic surgery

Background

The impact of patient ethnicity on healthcare delivery is well documented. In this study of children who had undergone open abdominal or pelvic surgery for tumor resection, we sought to compare the use of epidural analgesia or intraoperative blood transfusions between Caucasian and non-Caucasian children.

Methods

A retrospective study of 139 children was performed. Logistic regression models were used to evaluate the association between the specified perioperative factors and patient ethnicity.

Results

The average age (standard deviation) was 11 years (± 5), 50% were female, and 58% were Caucasian. Compared to Caucasian children, non-Caucasian children were younger (difference in mean, − 2.6 years; 95% confidence interval [− 4.3, − 0.9], p = 0.003), underwent shorter procedures (difference in mean anesthesia minutes, − 134; 95% confidence interval [−  230, − 39], p = 0.006), and had a lower proportion of patients who received epidural analgesia (66% versus 81%, p = 0.042) or blood transfusions (48% versus 65%, p = 0.039). In the adjusted model, patient ethnicity was not associated with the receipt of epidural analgesia (odds ratio 0.53, 95% confidence interval [0.23, 1.21], p = 0.132) or blood transfusions (odds ratio 0.77, 95% confidence interval [0.29, 2.04], p = 0.600). The use of epidural analgesia or blood transfusions was associated with abnormal coagulation factors (odds ratio 0.32, 95% confidence interval [0.14, 0.71], p = 0.005) and the duration of surgery (odds ratio 1.007, 95% confidence interval [1.005, 1.009], p < 0.001), respectively.

Conclusion

In this study of children who had undergone major oncologic surgery, the use of epidural analgesia or blood transfusions was not associated with patient ethnicity.

An analysis of the survival impact of dexmedetomidine in children undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy

OBJECTIVE

Recent evidence suggests the α2-adrenoreceptor agonist dexmedetomidine may promote metastasis of cancer cells. In this study we sought to evaluate the impact of dexmedetomidine administration on the survival of children and adolescents with cancer.

DESIGN

Retrospective chart review.

SETTING

Comprehensive cancer center.

PATIENTS

Children and adolescents who had undergone cytoreductive surgery with hyperthermic intraperitoneal chemotherapy for peritoneal carcinomatosis.

INTERVENTION

Intraoperative and/or early postoperative (within 24 hours of surgery) administration of dexmedetomidine.

MEASUREMENTS

Multivariable cox proportional hazard models were used to assess the association between dexmedetomidine administration and progression free survival (PFS) or overall survival (OS).

MAIN RESULTS

Ninety-three patients were identified. The median age was 12 years, 42% were female, and 35% received dexmedetomidine. There were no significant differences between the baseline and perioperative characteristics of patients who received dexmedetomidine and those who did not. In the multivariable analysis, the administration of dexmedetomidine was not associated with PFS (HR = 1.20, 95% CI [0.60-2.41], p = .606) or OS (HR = 0.81, 95% CI [0.35-1.85], p = .611).

CONCLUSION

In this retrospective study of children and adolescents who had undergone a major oncologic surgery, the intraoperative and/or early postoperative administration of dexmedetomidine was not associated with survival.

Metastatic Testicular Cancer to Left Atrium via the Left Inferior Pulmonary Vein: A Case Report

Testicular cancer is one of the most common cancers diagnosed in young men. Frequent sites of metastasis include the retroperitoneum, lungs, liver, brain, and bone. Intra-cardiac metastasis has also been described. An 18-year-old boy with a history of mixed testicular germ cell tumor presented to our institution for surgical resection of his metastatic disease. Intraoperative transesophageal echocardiography during his surgery confirmed a tumor thrombus into the left atrium coming from the left pulmonary vein. We report a case of metastatic testicular cancer with rare tumor extension from the left inferior pulmonary vein into the left atrium. Perioperative transesophageal echocardiography was necessary to aid intraoperative diagnosis and confirmation of the intracardiac tumor, providing data to guide surgical strategy.

The Use of Intraoperative Dexmedetomidine Is Not Associated With a Reduction in Acute Kidney Injury After Lung Cancer Surgery

OBJECTIVE

To evaluate whether the use of intraoperative dexmedetomidine (DEX) during lung cancer surgery may reduce the incidence of acute kidney injury (AKI).

DESIGN

A retrospective study.

SETTING

An academic hospital.

PARTICIPANTS

Data were collected from 1,207 adult patients who underwent resection for non-small-cell lung cancer between January 2004 and December 2012.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

All patients had a general balanced anesthetic technique, and dexmedetomidine use was at the discretion of the anesthesiologist. Data analysis was done utilizing the Wilcoxon rank sum tests and Chi-square tests to compare continuous variables and categoric variables between the 2 groups, respectively. Multivariate logistic analysis with backward selection was fitted to find out factors for AKI incidence. Overall, 8.1% of the patients developed AKI during their hospital stay. There were no statistically significant differences in demographic, perioperative variables, and the incidence of AKI between patients who did and did not receive DEX. A logistic regression model was fitted to determine factors independently associated with AKI. Factors that were independently associated with AKI included body mass index, American Society of Anesthesiologists 3-4, hypertension, smoking status, and thoracotomy procedure.

DISCUSSION

The authors hypothesized that DEX use would be associated with a decreased incidence of AKI in thoracic surgery; however, they were unable to prove this hypothesis. Their results did demonstrate that there are 5 factors independently associated with AKI.

Effect of phenethyl isothiocyanate on Ca2+ movement and viability in MDCK canine renal tubular cells

The effect of the natural compound phenethyl isothiocyanate (PEITC) on cytosolic Ca2+ concentrations ([Ca2+]i) and viability in MDCK renal cells is unknown. This study explored whether PEITC changed [Ca2+]i in MDCK cells using the Ca2+-sensitive fluorescent dye fura-2. PEITC at 200–700 μM increased [Ca2+]i in a concentration-dependent manner. The signal was reduced by removing extracellular Ca2+. PEITC-induced Ca2+ influx was inhibited by nifedipine, econazole, SK&F 96365 and protein kinase C modulators. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin (TG) or 2,5-di- tert-butylhydroquinone (BHQ) inhibited PEITC-induced rise in [Ca2+]i. Incubation with PEITC also inhibited TG or BHQ-induced rise in [Ca2+]i. Inhibition of phospholipase C with U73122 abolished PEITC-induced rise in [Ca2+]i. At 15–75 μM, PEITC decreased viability. The cytotoxic effect of PEITC was enhanced by chelating cytosolic Ca2+ with 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid/acetoxymethyl ester. Annexin V-FITC data suggest that 20 and 50 μM PEITC induced apoptosis. At 10 and 15 μM, PEITC did not increase reactive oxygen species (ROS) production. Together, in renal tubular cells, PEITC-induced rise in [Ca2+]i by inducing phospholipase C-dependent Ca2+ release from endoplasmic reticulum and Ca2+ entry via store-operated Ca2+ channels. PEITC induced apoptosis in a concentration-dependent, ROS/Ca2+-independent manner.

Effect of thimerosal on Ca2+ movement and viability in human oral cancer cells

The effect of thimerosal on cytosolic free Ca2+ concentrations ([Ca2+]i ) in human oral cancer cells (OC2) is unclear. This study explored whether thimerosal changed basal [Ca2+]i levels in suspended OC2 cells using fura-2. Thimerosal at concentrations between 1and 50 μM increased [Ca2+]i in a concentration-dependent manner. The Ca2+ signal was reduced partly by removing extracellular Ca 2+. Thimerosal-induced Ca2+ influx was not blocked by L-type Ca2+ entry inhibitors and protein kinase C modulators (phorbol 12-myristate 13-acetate [PMA] and GF109203X). In Ca2+-free medium, 50 μM thimerosal failed to induce a [Ca2+]i rise after pretreatment with thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor). Inhibition of phospholipase C with U73122 did not change thimerosal-induced [Ca2+]i rises. At concentrations between 5 and 10 μM, thimerosal killed cells in a concentration-dependent manner. The cytotoxic effect of 8 μM thimerosal was potentiated by prechelating cytosolic Ca2+ with the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetate/acetomethyl (BAPTA/ AM). Flow cytometry data suggested that 1—7 μM thimerosal-induced apoptosis in a concentration-dependent manner. Collectively, in OC2 cells, thimerosal-induced [Ca2+]i rises by causing phospholipase C-independent Ca2+ release from the endoplasmic reticulum and Ca2+ influx through non—L-type Ca2+ channels. Thimerosal killed cells in a concentration-dependent manner through apoptosis.

Optically modulated internal strain in InGaN quantum dots grown on SiN(x) nano masks

Optically modulated internal strain has been observed in InGaN quantum dots (QDs) deposited on SiN(x) nano masks. The modulated internal strain can induce a number of intriguing effects, including the change of refractive index and the redshift of InGaN A(1)(LO) phonon. The underlying mechanism can be well accounted for in terms of the variation of internal strain through the converse piezoelectric effect arising from the screening of the internal electric field due to spatial separation of photoexcited electrons and holes. Our results point out a convenient way for the fine tuning of physical properties in nitride-based semiconductor nanostructures, which is very important for high quality optoelectronic devices.

Antioxidant activities of cultured Armillariella mellea

This study aimed to evaluate the antioxidant activities of a cultured medicinal fungus--Armillariella mellea (Vahl. ex Fr.) Karst. (AM). Three antioxidant assay systems, namely cytochrome c, xanthine oxidase inhibition and FeCl2-ascorbic acid stimulated lipid peroxidation in rat tissue homogenate tests, were used. Total flavonoid and phenol contents of AM extracts were also analyzed. Results showed that both aqueous (AM-H2O) and ethanolic (AM-EtOH) extracts of solid state cultured AM showed antioxidant activities in a concentration-dependent manner. At concentrations 1-100 microg/ml, the free radical scavenging activity was 73.7-92.1% for AM-H2O, and 60.0-90.8% for AM-EtOH. These extracts also showed an inhibitory effect on xanthine oxidase activity, but with a lesser potency (IC50 - 9.17 microg/ml for AM-H2O and 7.48 microg/ml for AM-EtOH). In general, AM-H2O showed a stronger anti-lipid peroxidation activity on different rat's tissues than AM-EtOH. However, both AM extracts displayed a weak inhibitory effect on lipid peroxidation in plasma. Interestingly, the anti-lipid peroxidation activity of AM-H2O (IC50 - 6.66 microg/ml) in brain homogenate was as good as alpha-tocopherol (IC50 - 5.42 microg/ml). AM-H2O (80.0 mg/g) possessed a significant higher concentration of total flavonoids than AM-EtOH (30.0 mg/g), whereas no difference was noted in the total phenol content between these two extracts. These results conclude that AM extracts possess potent free radical scavenging and anti-lipid peroxidation activities, especially the AM-H20 in the brain homogenate.

Supercritical carbon dioxide extract exhibits enhanced antioxidant and anti-inflammatory activities of Physalis peruviana

Physalis peruviana L. (PP) is a medicinal herb widely used in folk medicine. In this study, supercritical carbon dioxide (SFE-CO2) method was employed to obtain three different PP extracts, namely SCEPP-0, SCEPP-4 and SCEPP-5. The total flavonoid and phenol concentrations, as well as antioxidant and anti-inflammatory activities of these extracts were analyzed and compared with aqueous and ethanolic PP extracts. Among all the extracts tested, SCEPP-5 demonstrated the highest total flavonoid (234.63+/-9.61 mg/g) and phenol (90.80+/-2.21 mg/g) contents. At concentrations 0.1-30 microg/ml, SCEPP-5 also demonstrated the strongest superoxide anion scavenging activity and xanthine oxidase inhibitory effect. At 30 microg/ml, SCEPP-5 significantly prevented lipopolysaccharide (LPS; 1 microg/ml)-induced cell cytotoxicity in murine macrophage (Raw 264.7) cells. At 10-50 microg/ml, it also significantly inhibited LPS-induced NO release and PGE2 formation in a dose-dependent pattern. SCEPP-5 at 30 microg/ml remarkably blocked the LPS induction of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. Taken together, these results suggest that SCEPP-5, an extract of SFE-CO2, displayed the strongest antioxidant and anti-inflammatory activities as compared to other extracts. Its protection against LPS-induced inflammation could be through the inhibition of iNOS and COX-2 expression.

Crystallization and preliminary X-ray diffraction analysis of spermidine synthase fromHelicobacter pylori

Polyamines, such as putrescine, spermidine and spermine, are essential for the regulation of cell proliferation and differentiation in most organisms. Spermidine synthase catalyzes the transfer of the aminopropyl group from decarboxylated S-adenosylmethionine to putrescine in the biosynthesis of spermidine. In this study, spermidine synthase of Helicobacter pylori has been overexpressed in Escherichia coli and purified. Two kinds of spermidine synthase crystals were obtained. One belongs to the monoclinic P2(1) space group, with unit-cell parameters a = 62.78, b = 58.24, c = 74.28 A, beta = 90.9 degrees , and the other belongs to the orthorhombic C222(1) space group, with unit-cell parameters a = 100.43, b = 128.55, c = 143.60 A.

Diagnosis, pathology, staging, treatment, and outcome of epithelial ovarian neoplasia in patients age < 21 years

BACKGROUND

Epithelial ovarian neoplasms are rare in patients under the age of 21 years. This is a report of a series of such patients documenting their presentation, histologic type, stage of disease, treatment, and outcome.

METHODS

Clinical findings, histology, stage, treatment, and outcomes of 19 patients with epithelial ovarian neoplasia are reported. All histology was rereviewed.

RESULTS

The median age at the time of diagnosis was 19.7 years (range, 14.1-21.8 years), and the median follow-up was 5.6 years (range, 0.2-19.5 years). The most common presenting symptom was dysmenorrhea (100%) followed by abdominal pain (68%), and the initial diagnosis usually was made ultrasonographically. There were nine (47%) serous tumors, 7 (37%) mucinous tumors, 2 (11%) small cell carcinomas, and 1 (5%) endometrioid carcinoma. Seventy-nine percent of tumors were unilateral, and 84% were low malignant potential or well differentiated tumors. Surgical treatment included unilateral salpingo-oophorectomy in 12 patients (63%), total abdominal hysterectomy and bilateral salpingo-oophorectomy in 6 patients (32%), and ovarian cystectomy in 1 patient (5%). Fifteen patients (79%) had Stage I disease, and 4 patients (21%) had Stage III disease at the time of diagnosis. There were two deaths in this series, and both occurred in patients with small cell anaplastic carcinoma.

CONCLUSIONS

Epithelial ovarian neoplasias are rare in patients in this age group but must be included in the differential diagnosis of an ovarian mass. Most patients present with Stage I tumors of low malignant potential. In these patients, good survival is achieved with unilateral salpingo-oophorectomy and preservation of fertility. In contrast, small cell carcinomas are very aggressive, and patients with this variant require intensive therapy.

In vitro effect of hyperbaric oxygen on the chemolysis of infective stones

BACKGROUND

In order to extend the feasibility of hyperbaric oxygen therapy in the urological field, the present study aimed to investigate the dissolution activity of human infective stones in UROCITRA solution under hyperbaric oxygen condition.

METHODS

The dissolution activity of 7 struvite and 11 mixed struvite and carbonate apatite stones in UROCITRA solution were studied under 2.5 atmosphere (atm) hyperbaric oxygen (HBO) status in a Sigma I N-124 monoplace chamber. Another 7 struvite and 10 mixed struvite and carbonate apatite stones were also studied under normal condition. Chemolysis was performed in a drip device with a 150-ml/hour continuous flow rate.

RESULTS

Under 2.5 atm HBO status, the PO2 of UROCITRA solution was 365 +/- 44 mmHg, which was significantly higher than that of tap water (113 +/- 62 mmHg) and UROCITRA solution (125 +/- 12 mmHg) under normobaric condition (p < 0.001). The decreases in the stone weight of struvite under normobaric condition were 31 +/- 8.8% after 2 h and 48 +/- 15% after 4 h of treatment. The HBO-enriched UROCITRA solution did not increase the dissolution activity as reflected by comparable decreases in the dried stone weight (31.2 +/- 14.6% and 54 +/- 19% at the 2nd and 4th post-treatment hours, respectively, p > 0.05). Similarly, there was no significant difference in the percent stone weight decrease of the mixed struvite and carbonate apatite stones under either HBO or normobaric condition. The dissolution responsiveness of struvite was significantly greater than that of the mixed struvite and carbonate apatite stones.

CONCLUSIONS

The chemolysis of struvite in UROCITRA solution is significantly greater than that of the mixed struvite and carbonate apatite stones. However, the UROCITRA solution enriched with HBO does not enhance the dissolution of infective stones.

Transition-state analogue inhibitors of gamma-secretase bind directly to presenilin-1

The beta-amyloid precursor protein (beta-APP), which is involved in the pathogenesis of Alzheimer's disease, and the Notch receptor, which is responsible for critical signalling events during development, both undergo unusual proteolysis within their transmembrane domains by unknown gamma-secretases. Here we show that an affinity reagent designed to interact with the active site of gamma-secretase binds directly and specifically to heterodimeric forms of presenilins, polytopic proteins that are mutated in hereditary Alzheimer's and are known mediators of gamma-secretase cleavage of both beta-APP and Notch. These results provide evidence that heterodimeric presenilins contain the active site of gamma-secretase, and validate presenilins as principal targets for the design of drugs to treat and prevent Alzheimer's disease.

Aldose reductase, a key enzyme in the oxidative deamination of norepinephrine in rats

The sympathoneural neurotransmitter norepinephrine (NE) is deaminated to 3,4-dihydroxymandelaldehyde (DHMAL) and subsequently converted to either 3,4-dihydroxymandelic acid (DHMA) or 3,4-dihydroxyphenylglycol (DHPG). In this study, we investigated the relative importance of aldose reductase versus aldehyde reductase in the formation of DHPG from DHMAL. The in vitro incubation of NE with aldose reductase in the presence of monoamine oxidase (MAO) resulted in the formation of DHPG, which was confirmed by mass spectrometry. Although aldehyde reductase also generated DHPG, its activity was much lower than that of aldose reductase. With northern blotting, the expression of both aldose reductase and aldehyde reductase was detected in rat superior cervical ganglia. However, with western blotting, only aldose reductase was immunologically detectable. Treatment of rats with aldose reductase inhibitors for 3 days increased the plasma level of DHMA. There was no correlation between the selectivity of inhibitors and effects on NE metabolite levels. A significant decrease in DHPG, however, was obtained only with an extremely high dose (9 mg/kg/day) of the nonselective inhibitor AL 1576. The present study confirmed that aldose reductase generates DHPG from NE in the presence of MAO. In rat sympathetic neurons, aldose reductase appears to be more important than aldehyde reductase for the formation of DHPG. However, when aldose reductase is inhibited, it appears that aldehyde reductase can compensate for the conversion of DHMAL to DHPG, indicating redundancy in the reduction pathway.

The efficacy of potassium citrate based medical prophylaxis for preventing upper urinary tract calculi: a midterm followup study

PURPOSE

We examined the efficacy of potassium citrate based medical prophylaxis for preventing upper urinary calculous recurrence, and compared it with the stone recurrence rate in patients who only received intermittent or no medical prophylaxis.

MATERIALS AND METHODS

We retrospectively reviewed the records of 493 patients with upper urinary calculi, of whom 237 men and 76 women with a mean age of 56.1 and 51.4 years, respectively, were enrolled in the study. Of the 313 participants 64 (group 1, 20.4%) received regular medical prophylaxis for 24 to 42 months (mean 27.8), 80 (group 2, 25.6%) received intermittent medical prophylaxis for 1.5 to 19 months (mean 7.9) and 169 (group 3, 54%) did not receive any medical prophylaxis.

RESULTS

At midterm followup of 24 to 60 months 107 patients (34.2%) had stone recurrence. In group 1 the stone recurrence rate was 7.8%, which was significantly less (p <0.001) than in groups 2 (30%) and 3 (46.2%). Similarly new calculous events in patients with a history of multiple stone recurrence were less frequent in group 1 than in groups 2 and 3 (9.7, 47.4 and 52.2%, respectively, p <0.001). Multiple stone recurrence history, hypercalciuria, hyperuricosuria and calcium oxalate dihydrate calculi were independent risk factors for stone recurrence.

CONCLUSIONS

Regular medical prophylaxis may effectively prevent stone recurrence regardless of previous treatment modalities, stone composition, metabolic abnormalities and stone-free status. Cost effectiveness, patient compliance and gastrointestinal upset may limit patient acceptability and clinical use of medical prophylaxis. However, patients with a history of multiple stone recurrence, calcium oxalate dihydrate stones, hypercalciuria and hyperuricosuria benefit from regular medical prophylaxis.

Neutrophils in galactose-fed dogs: suppressed apoptosis and increased adhesion to retinal capillary endothelial cells

Dogs fed a diet containing 30% galactose develop diabetes-like retinal capillary changes. As retinal capillary occlusion is commonly observed in diabetic retinopathy, neutrophil apoptosis and the interaction of neutrophils with retinal capillary endothelial cells were investigated. Neutrophils were isolated with Ficoll-Hypaque centrifugation from dogs fed a 30% galactose diet and dogs fed a normal, control diet containing 30% non-nutrient filler. Apoptosis of neutrophils was microscopically examined after incubation at 37 degrees C for 3 hours with either 100 U/mL tumor necrosis factor alpha (TNF-alpha), 2 microg/mL cycloheximide or 50 ng/mL phorbol 12-myristate 13-acetate (PMA). Neutrophil adhesion to dog retinal capillary endothelial cells was examined by counting the cells attached to the surface of endothelial cells after the incubation in the presence of either 100 U/mL TNF-alpha or 5 microg/mL lipopolysaccharides (LPS) at 37 degrees C for 3 hours. With all three stimulants TNF-alpha, cycloheximide and PMA, the rate of apoptosis was significantly lower for neutrophils isolated from galactose-fed dogs compared to control dogs fed a normal diet. Preincubation of neutrophils from control dogs in medium containing 30% galactose for 3 hours did not affect the rate of apoptosis. Neutrophil adhesion to retinal capillary endothelial cells induced by incubation in the presence of either 100 U/mL TNF-alpha or 5 microg/ml LPS was significantly higher with neutrophils isolated from galactose-fed dogs than those from control dogs. The data indicate that long-term galactose feeding is essential with development of various neutrophil dysfunctions. These neutrophil changes may contribute to the development of retinal microangiopathy associated with diabetes and galactosemia.

Polyol formation and NADPH-dependent reductases in dog retinal capillary pericytes and endothelial cells

PURPOSE

Dogs fed a diet containing 30% galactose experience retinal vascular changes similar to those in human diabetic retinopathy, with selective pericyte loss as an initial lesion. In the present study the relationship among reduced nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reductases, polyol formation, and flux through the polyol pathway in cultured dog retinal capillary cells were investigated.

METHODS

Pericytes and endothelial cells were cultured from retina of beagle dogs. NADPH-dependent reductases were characterized by chromatofocusing after gel filtration. Sugars in cultured cells were analyzed by gas chromatography, and flux through the polyol pathway was investigated by 19F nuclear magnetic resonance (NMR) with 3-fluoro-3-deoxy-D-glucose (3FG) as a substrate. The presence of aldose reductase and sorbitol dehydrogenase in these cells was examined by northern blot analysis.

RESULTS

Two distinct peaks corresponding to aldose reductase and aldehyde reductase, the latter being dominant, were observed in pericytes by chromatofocusing. Culture in medium containing either 10 mM D-galactose or 30 mM D-glucose resulted in the accumulation of sugar alcohol in pericytes that was markedly reduced by aldose reductase inhibitors. 19F NMR spectra obtained from pericytes cultured for 5 days in medium containing 2 mM 3FG displayed the marked accumulation of 3-fluoro-deoxysorbitol but not 3-fluoro-deoxyfructose. No 3FG metabolism was observed in similarly cultured endothelial cells. With northern blot analysis, aldose reductase was detected in pericytes but not in endothelial cells. Sorbitol dehydrogenase was below the detectable limit in pericytes and endothelial cells.

CONCLUSIONS

Aldose, aldehyde, and glyceraldehyde reductases are present in dog retinal capillary pericytes, with aldehyde reductase being the major reductase present. Polyol accumulation easily occurs in pericytes but not in endothelial cells.

Esophageal atresia and tracheoesophageal fistula: surgical experience over two decades

BACKGROUND

Despite improvements in survival, for infants born with esophageal atresia tracheoesophageal fistula, or both, the morbidity associated with repair of these anomalies remains high.

METHODS

This report retrospectively analyzes 81 patients with esophageal atresia, tracheoesophageal fistula, or both presenting to our institution between 1975 and 1995, with a focus on anastomotic complications.

RESULTS

There were 46 male and 35 female patients with a mean gestational age of 37 weeks and mean birth weight of 2443 g. Forty-four patients underwent primary esophageal anastomoses, 7 underwent delayed primary anastomoses, 12 patients underwent staged repairs, and 5 underwent repair of H-type fistulas. Among 62 patients with anastomoses, complications included stricture in 25/62 patients (40%), leakage in 12/62 patients (19%), and recurrent tracheoesophageal fistulas in 6/62 patients (10%). Stricture rates for esophagoclonic anastomoses versus esophagoesophageal anastomoses were 4/8 cases (50%) versus 21/54 cases (39%). This difference was not statistically significant. All esophagoesophageal strictures were managed successfully with dilations; three of four esophagocolonic strictures required anastomotic revision. The leakage rate for esophagocolonic anastomoses versus esophagoesophageal anastomoses was 6/8 cases (75%) versus 6/54 cases (11%). This difference was statistically significant (p = 0.0003). Two patients required revision of their colon grafts secondary to necrosis. Eighteen of 81 patients (22%) died. Operative mortality was 9/74 (12%). Causes of death included associated anomalies (n = 15), recurrent aspiration and sepsis secondary to missed fistula (n = 1), and unknown (n = 2).

CONCLUSIONS

Although the morbidity associated with surgical repair of these anomalies is high, this does not affect the overall survival. The high complication rate associated with colonic interposition suggests that one should preserve the native esophagus as a primary conduit whenever feasible.

Complementary deoxyribonucleic acid cloning and characterization of mSP-10: the mouse homologue of human acrosomal protein SP-10

Complementary DNA encoding the putative mouse homologue for human acrosomal protein SP-10, a candidate contraceptive vaccinogen, was cloned and sequenced. The entire open reading frame (amino acids 18 to 261) of the mouse SP-10 (mSP-10), with the exception of the signal peptide (amino acids 1 to 17), was placed under the influence of inducible T7 RNA polymerase/promoter system to overproduce recombinant protein (re-mSP-10) in Escherichia coli. A six-histidine tag, which was coexpressed at the carboxyl terminus of re-mSP-10, provided the means for purification of re-mSP-10 by immobilized metal chelation affinity chromatography technique. The level of purity of re-mSP-10 thus obtained was determined by 2-dimensional gel electrophoresis to be 98%. Immunoblotting with monoclonal and polyclonal antibodies previously generated against human or baboon SP-10 showed that mSP-10 shared significant antigenic similarity with its primate counterparts. The position of mSP-10 in the mouse genome was next mapped through segregation analysis of an interspecific backcross panel of 96 animals. Acrv1 (assigned gene symbol for mSP-10) was localized in the proximal portion of mouse chromosome 9 in a region that exhibits synteny with human 11q23, the region to which ACRV1 (gene symbol for human SP-10) was previously mapped. These characterizations by combined immunological and gene mapping techniques established the cloned mSP-10 to be the mouse homologue of SP-10.

Localization of the Mas proto-oncogene to a densely marked region of mouse chromosome 17 associated with genomic imprinting

The mouse homolog of the human proto-oncogene MAS was mapped by two interspecific backcrosses to the proximal portion of MMU17. Higher resolution mapping was accomplished through the analysis of genotypes duplicated or deleted for a megabase-size subregion within MMU17. The results demonstrate a map position for Mas in the close vicinity of Igf2r, which encodes another membrane receptor known to undergo genomic imprinting. The data provide further evidence for the clustering of genes in a 1-Mb region of chromosome 17, with the absence of any identified genes in a nearby region likely to be six times larger.

Escape from genomic imprinting at the mouse T-associated maternal effect (Tme) locus

Genomic imprinting occurs at the paternally inherited allele of the mouse T-associated maternal effect (Tme) locus. As a consequence, maternal transmission of a functional Tme gene is normally required for viability and individuals that receive a Tme-deleted chromosome (Thp or tlub2) from their mother die late in gestation or shortly thereafter. Here we report that a rearranged paternally derived chromosome duplicated for the Tme locus can act to rescue animals that have not received a maternal copy of the Tme locus. Unexpectedly, all rescued animals display an abnormal short/kinky tail phenotype. Somatic transfer of genomic imprinting between homologs by means of a transvection-like process between paired Tme and T loci is proposed as a model to explain the results obtained.

Two-dimensional gel analysis of complex DNA families: methodology and apparatus

We describe a reproducible protocol for the analysis of individual members of complex mammalian gene families by gel fractionation in two dimensions within a specially designed, easily built electrophoretic apparatus. We have used this protocol to resolve the family of mouse H-2 class I genes, with approximately 30 members, as well as two different families of endogenous retroviral-like sequences, each of which has approximately 180 members dispersed throughout the genome. The results demonstrate the feasibility of using this protocol for rapid, whole genome analysis of individual animals and cell lines. Two-dimensional DNA analysis of highly repeated retroviral-like DNA families could be applied to genetic mapping and cloning experiments as well as to obtaining whole genome fingerprints in the analysis of somatic cell hybrid lines that contain a subset of chromosomes from the genome of interest.

Human homologs of two testes-expressed loci on mouse chromosome 17 map to opposite arms of chromosome 6

Our laboratory has recently cloned and characterized two testes-expressed loci--the Tcp-10 gene family cluster and the D17Si11 gene--that map to the proximal portion of mouse chromosome 17. Human homologs of both loci have been identified and cloned. Somatic cell hybrid lines have been used to map the human homolog of D17Si11 to the short arm of chromosome 6 (p11-p21.1) along with homologs of other genes from the (Pim-1)-(Pgk-2) region of the mouse chromosome. The human TCP 10 locus maps to the long arm of chromosome 6 (q21-qter) along with homologs of other genes from the mouse chromosome 17 region between the centromere and Pim-1. The mapping of large portions of the mouse t haplotype to unlinked regions on human chromosome 6 rules out the possibility that a t-haplotype-like chromosome could exist in humans.

A mouse chromosome 17 gene encodes a testes-specific transcript with unusual properties

We have characterized a novel mouse gene (D17Si11) on chromosome 17 that expresses a major transcript observed uniquely in the testes. The D17Si11 locus has been mapped to the central region of chromosome 17 between H-2 and C3. Sequence analysis demonstrates several unusual features of this locus and its transcript: first is the presence of complementary sets of alternating purine and pyrimidine residues within the 3' region of the transcript that could form double-stranded, hairpin-like secondary structures with properties similar to that of Z-DNA; second is the existence of a hypothetical, long open reading frame in the nucleotide strand that is complementary to the testes transcripts. This complementary strand open reading frame is three times the size of the longest potential open reading frame present in the transcript itself. Although a function for D17Si11 has yet to be determined, the gene is relatively nonpolymorphic in mice and appears conserved in mammals.