Preliminary evidence for neural responsiveness to infants in mothers with schizophrenia and the implications for healthy parenting

Schizophrenia is a severe mental illness that may significantly affect maternal sensitive behaviour. Neural correlates of maternal behaviour represent a potentially valuable means of differentiating objectively between healthy mothers expressing variations in maternal sensitivity. As mothers with schizophrenia (MWS) show deficits in behavioural responses to infants compared to healthy mothers, we explored whether maternal brain responses to infant stimuli would be significantly reduced in MWS. We also examined whether differences in maternal behaviour between healthy and ill mothers (during play interactions with own infant) were associated with differences in brain activation to infant stimuli. We found no evidence of differential 'maternal brain' responses or 'maternal behavioural' responses in 11 new MWS compared to 20 healthy new mums; neither were neural responses to infants linked to behavioural or cognitive aspects of the mother's relationship with her infant in MWS. These preliminary findings suggest maternal sensitivity differences between MWS and healthy mothers, suggested in previous studies, may be reversible in stable treated MWS.

State-dependent changes in hippocampal grey matter in depression

Reduced hippocampal volume has been reported in depression and may be involved in the aetiology of depressive symptoms and vulnerability to depressive relapse. Neuroplasticity following antidepressant drug treatment in the hippocampus has been demonstrated in animal models but adaptive changes after such treatment have not been shown in humans. In this study, we determined whether grey matter loss in the hippocampus in depression (1) is present in medication-free depressed (2) changes in response to antidepressant treatment and (3) is present as a stable trait in medication-free remitted patients. Sixty-four medication-free unipolar depressed patients: 39 currently depressed and 25 in remission, and 66 healthy controls (HC) underwent structural magnetic resonance imaging in a cross-sectional and longitudinal design. Thirty-two currently depressed participants were then treated with the antidepressant citalopram for 8 weeks. Adherence to treatment was evaluated by measuring plasma citalopram concentration. We measured regional variation in grey matter concentration by using voxel-based morphometry-Diffeomorphic Anatomical Registration Through Exponentiated Lie algebra. Patients with current depression had bilaterally reduced grey matter in the hippocampus compared with HC and untreated patients in stable remission with the latter groups not differing. An increase in grey matter was observed in the hippocampus following treatment with citalopram in currently depressed patients. Grey matter reduction in the hippocampus appears specific to the depressed state and is a potential biomarker for a depressive episode.

Non-inferiority trial between two dry-powder inhalers containing fluticasone/salmeterol in asthmatic patients

Asthma is an increasing pathology with poor compliance. Achievement of control is possible but under intensive treatment. In this setting, fluticasone/salmeterol association delivered by dry powder inhalers is a valuable and proved option. A prospective, parallel, open-label, phase IV, multicentre non-inferiority study was conducted to determine therapeutic similarity between 2 different inhalers: Generic DPI and Diskus®, which both deliver a fluticasone/salmeterol association (CAS 80474-14-2/CAS 89365-50-4). A 103 uncontrolled asthmatic patients were randomly assigned in 2 groups, Generic (G) and Diskus® (D), and received the association for 18 weeks through the appropriate device. They were evaluated according to Asthma Quality of Life Questionnaire and GINA/NIH guidelines. To demonstrate non-inferiority, the estimation of the Relative Risk between the Global Score Rate per group with its 95% confidence interval was calculated and compared against a non-inferiority margin obtained from a previous study. The Global Score Rate was 82% for G Group and 83% for D Group. The RR was 1.0124 (95% CI: 0.847-1.210). The margin set at 0.832 was not reached by the lower 95% CI (z=-2.097; p=0.018) pointing out non-inferiority. The results have demonstrated non-inferiority between groups. Thus, the 2 products are therapeutically similar.

Interaction between a history of depression and rumination on neural response to emotional faces

BACKGROUND

Both past depressive episodes and the personality trait of depressive rumination are strong risk factors for future depression. Depression is associated with abnormal emotional processing, which may be a neurobiological marker for vulnerability to depression. A consistent picture has yet to emerge as to how a history of depression and the tendency to ruminate influence emotional processing. The aim of this study was to investigate the relationship between rumination, past depression and neural responses when processing face emotions.

METHOD

The Ruminative Responses Scale (RRS) was completed by 30 remitted depressives and 37 controls who underwent functional magnetic resonance imaging (fMRI) scanning while viewing happy, sad, fearful and neutral faces.

RESULTS

The remitted depressives showed overall reductions in neural responses to negative emotions relative to the controls. However, in the remitted depressives, but not the controls, RRS scores were correlated with increased neural responses to negative emotions and decreased responses to happiness in limbic regions.

CONCLUSIONS

Automatic emotion processing biases and rumination seem to be correlated to aspects of vulnerability to depression. However, remission from depression may be maintained by a general suppression of limbic responsiveness to negative emotion.

Heme oxygenase in the retina in diabetes

INTRODUCTION

Heme oxygenase (HO) isoforms, HO-1, and HO-2, are responsible for heme breakdown to iron and carbon monoxide (CO). HO may respond to oxidative stress and may modulate the expression of vasoactive factors like nitric oxide (NO). Since diabetes induced oxidative stress may change HO, the present study examined whether diabetes is associated with HO alterations, its relationship with NO, endothelin-1(ET-1) and the functional significance.

MATERIALS AND METHODS

Male SD rats with Streptozotocin induced diabetes were investigated after six-weeks. Poorly controlled diabetic animals were randomized to one of three treatment groups (n = 6 each group); a) untreated, b) HO-1 inhibitor SnPP-IX (50 micromol/kgIP/day), c) NO donor molsidomine (120 mg/L PO/day) and were compared with age and sex matched non diabetic control animals with or without SnPP-IX treatment. Color Doppler ultrasound analysis was used to determine retinal resistivity index (RI). mRNA for HO-1, HO-2, ET-1, eNOS and iNOS were analyzed with competitive RT-PCR. HO distribution in the retina was investigated by immunocytochemistry.

RESULTS

Diabetic animals expressed lower body weight, higher blood glucose and increased glycated hemoglobin levels. HO-1 and HO-2 immuno-reactivity were identified in the retina. Diabetes induced increased RI was associated with up-regulation of both ET-1 and HO-1 mRNA expression but not eNOS or iNOS mRNA. Both SnPP-IX and molsidomine treatments prevented a diabetes increase of RI, in spite of increased ET-1 expression and were associated with increased iNOS mRNA.

CONCLUSIONS

The present data suggests that the HO system is up-regulated in short term diabetes leading to HO and NO interactions which may modulate vascular function in the retina.

Self-reported Rumination as Trait Marker for Depression: Evidence from Functional Neuroimaging

Background:

Research using fMRI indicates that sustained limbic activity is linked to processing negative words and self-reported rumination in currently depressed individuals. It is unknown whether this is also present in remitted depressed individuals. We tested the hypothesis that a tendency to ruminate constitutes a trait for depression by using a standard covert fMRI emotional task face in previously and never depressed volunteers and postulated that high rumination scores would correlate with activity in brain areas previously associated with depression.

Methods:

37 controls (25 female) and 30 remitted depressed (RD, 22 female) were enrolled. Volunteers completed the Ruminative Responses Scale (RRS) and underwent fMRI scanning using a standard covert fMRI emotional task faces. Significance level was set at p < 0.05 (FWE).

Results:

With RRS score controlled for RD showed reduced subcortical and limbic activity to sad and fearful faces compared to controls. Correlations between RRS scores and neural activity in all participants and control participants alone were very limited. However, in RD, RRS score was negatively correlated with neural response to happy faces and positively correlated with neural response to sad and fearful faces, in cortical and limbic regions associated with depression (hippocampus, thalamus, caudate, insula and cingulate gyrus).

Conclusion:

The results suggest that reduced limbic activity is associated with remission, possibly as a maintenance mechanism. However, within the remitted group the more ruminative participants show greater response in these areas to negative stimuli, and less to positive stimuli. This could be a neurobiological marker for risk of relapse

Self-reported Rumination as Trait Marker for Depression: Evidence from Functional Neuroimaging

Background:

Research using fMRI indicates that sustained limbic activity is linked to processing negative words and self-reported rumination in currently depressed individuals. It is unknown whether this is also present in remitted depressed individuals. We tested the hypothesis that a tendency to ruminate constitutes a trait for depression by using a standard covert fMRI emotional task face in previously and never depressed volunteers and postulated that high rumination scores would correlate with activity in brain areas previously associated with depression.

Methods:

37 controls (25 female) and 30 remitted depressed (RD, 22 female) were enrolled. Volunteers completed the Ruminative Responses Scale (RRS) and underwent fMRI scanning using a standard covert fMRI emotional task faces. Significance level was set at p < 0.05 (FWE).

Results:

With RRS score controlled for RD showed reduced subcortical and limbic activity to sad and fearful faces compared to controls. Correlations between RRS scores and neural activity in all participants and control participants alone were very limited. However, in RD, RRS score was negatively correlated with neural response to happy faces and positively correlated with neural response to sad and fearful faces, in cortical and limbic regions associated with depression (hippocampus, thalamus, caudate, insula and cingulate gyrus).

Conclusion:

The results suggest that reduced limbic activity is associated with remission, possibly as a maintenance mechanism. However, within the remitted group the more ruminative participants show greater response in these areas to negative stimuli, and less to positive stimuli. This could be a neurobiological marker for risk of relapse.

In situ transmissiometer measurements for real-time monitoring of dust discharge during orchard nut harvesting

Rapid assessments of operating conditions and field preparation on dust discharge from nut harvesters are needed to guide improved equipment design and grower practices for dust reduction. An industrial opacity sensor, typically used for industrial stack monitoring, was adapted for use on a nut harvester to measure relative dust intensity during nut pick-up operations in almond orchards. Due to the high volume of discharge air and the presence of large debris such as leaves, additional components were coupled with the sensor to enable subsampling of the air. Pre-harvest windrow preparation conditions were evaluated. Results indicated that relative dust intensity decreased by 32% during harvest activities after windrow preparation with proper nut sweeper adjustment. Conventional harvesting results indicated that under typical operating conditions, reducing the separation fan speed could reduce relative dust intensity by 54%. Ground speed also had a strong effect; reducing speed from 4.8 to 2.4 km h(-1) reduced opacity of discharged air by 50%. The measurement system was also mounted on a separate vehicle and used as a tool for comparing modifications in harvest machine designs where direct measurement of discharge may not be feasible due to mechanical constraints. A comparison between a conventional harvester and one modification in the harvester design found that the machine modification decreased relative dust intensity by 73%. The measurement tools described in this work can be used to provide rapid feedback on harvester operating conditions, orchard cultural practices, and machine design modifications.

Slice-Based Prostate Segmentation in 3D US Images Using Continuity Constraint

In the diagnosis and therapy of prostate cancer, it is critical to measure the volume of the prostate and locate its boundary. Three-dimensional transrectal ultrasound (3D TRUS) imaging has been demonstrated to be a useful technique to perform such a task. Due to image speckle as well as low contrast in ultrasound images, segmentation of the prostate in 3D US images is challenging. In this paper, we report on the development of an improved slice-based 3D prostate segmentation method. First, we imposed a continuity constraint for the end points of the prostate boundaries in a cross-sectional plane so that a smooth prostate boundary in 2D is obtained. Then, in each 2D slice, we inserted the end points into the vertex list of the initial contour to obtain a new contour, which forces the evolving contour to be driven to the boundary of the prostate. Evaluation demonstrated that our method could segment the prostate in 3D TRUS images more quickly and accurately.

Dynamic Intraoperative Prostate Brachytherapy Using 3D TRUS Guidance with Robot Assistance

This paper describes a system for dynamic intraoperative prostate brachytherapy using 3D ultrasound guidance with robotic assistance. The system consists of 3D TRUS imaging, a robot and software for prostate segmentation, intraoperative planning, oblique needle segmentation and tracking, seed segmentation, and 3D dose planning. The robot and 3D TRUS coordinate systems are unified through robot and image calibrations. In 3D ultrasound images, the prostate is segmented using the discrete dynamic contour method, and optimal implantation plan is performed using geometric optimization followed by simulated annealing. The inserted needles are segmented and tracked using grey-level change in near real-time, and seed segmentation is performed using 3D line segment patterns. Needle placement accuracy of the robot at the "patient" skin was 0.15mm&#177; 0.06mm, and needle angulation error was 0.07&#176;. Needle targeting accuracy was 0.79mm&#177;0.32mm.

3D prostate model formation from non-parallel 2D ultrasound biopsy images

Biopsy of the prostate using 2D transrectal ultrasound (TRUS) guidance is the current gold standard for diagnosis of prostate cancer; however, the current procedure is limited by using 2D biopsy tools to target 3D biopsy locations. We propose a technique for patient-specific 3D prostate model reconstruction from a sparse collection of non-parallel 2D TRUS biopsy images. Our method conforms to the restrictions of current TRUS biopsy equipment and could be efficiently incorporated into current clinical biopsy procedures for needle guidance without the need for expensive hardware additions. In this paper, the model reconstruction technique is evaluated using simulated biopsy images from 3D TRUS prostate images of 10 biopsy patients. All reconstructed models are compared to their corresponding 3D manually segmented prostate models for evaluation of prostate volume accuracy and surface errors (both regional and global). The number of 2D TRUS biopsy images used for prostate modeling was varied to determine the optimal number of images necessary for accurate prostate surface estimation.

Intraoperative laparoscopic renal ultrasonography: Use in advanced laparoscopic renal surgery

OBJECTIVES

To highlight the use of intraoperative laparoscopic ultrasonography (ILUS) in complex renal surgery, as well its impact on management. ILUS has been used to facilitate advanced laparoscopic surgery, but only limited descriptions of the indications for its use have been published.

METHODS

All patients undergoing laparoscopic renal procedures requiring ILUS from October 2001 to March 2005 were reviewed. A total of 50 cases, including 35 partial nephrectomies, cryoablation of 6 renal tumors, 6 radical nephrectomies, 2 perinephric explorations, and 1 resection of a renal artery aneurysm were assessed by ILUS.

RESULTS

The average tumor size in the patients undergoing laparoscopic partial nephrectomy was 3.1 cm (range 1.4 to 8.0), and all margins were negative. Also, a previously unidentified satellite lesion was found in 1 patient. ILUS was essential in assessing iceball formation during laparoscopic renal cryotherapy. ILUS also proved useful in defining the anatomy during laparoscopic perinephric exploration, assessing renal vein thrombi during laparoscopic nephrectomy, and evaluating renal perfusion during laparoscopic renal artery aneurysm repair.

CONCLUSIONS

ILUS can be extremely useful in advanced laparoscopic renal surgery. In a number of situations, it is an essential surgical tool. With expanding indications for laparoscopic surgery, the indications for ILUS continue to grow.

3D TRUS guided robot assisted prostate brachytherapy

This paper describes a system for dynamic intraoperative prostate brachytherapy using 3D ultrasound guidance with robot assistance. The system consists of 3D transrectal ultrasound (TRUS) imaging, a robot and software for prostate segmentation, 3D dose planning, oblique needle segmentation and tracking, seed segmentation, and dynamic re-planning and verification. The needle targeting accuracy of the system was 0.79 mm +/- 0.32 mm in a phantom study.

Assessing the Prognostic Significance of Transrectal Ultrasound Extracapsular Extension in Prostate Cancer

AIMS

To determine the prognostic value of transrectal ultrasound (TRUS)-detected extraprostatic disease for prostate cancer in patients receiving radical external-beam radiation therapy (EBRT).

MATERIALS AND METHODS

A chart review of 181 patients treated with radical EBRT for prostate cancer was conducted. All patients underwent TRUS assessment by one radiologist. The median radiation dose delivered to the prostate was 66 Gy (range 53-70 Gy) in 33 fractions (range 20-39 fractions). Median follow-up time for all patients was 6.5 years. Sixty-four (35%) out of 181 patients were found to have extracapsular disease on TRUS. Clinical relapse was defined as the first occurrence of either salvage hormonal therapy administration by the treating oncologist or clinical, radiological, and/or pathologic evidence of recurrent or progressive disease. In terms of biochemical failure, two prognostic variable analyses were carried out using both the American Society for Therapeutic Radiology and Oncology (ASTRO) consensus guidelines and the Houston definition of biochemical failure. The primary end point for the prognostic variable analyses was time to first clinical or biochemical failure (CBF).

RESULTS

For time to CBF using the ASTRO consensus guidelines for biochemical failure, univariable analysis revealed that the prostate-specific antigen (PSA) (P = 0.018), clinical T stage (P = 0.002), Gleason score (P = 0.021), adjuvant hormonal therapy (P = 0.032) and TRUS T staging (P = 0.0001) were statistically significant prognostic factors. On multivariable analysis, clinical T stage (P = 0.051) was of borderline statistical significance, whereas PSA (P = 0.036), TRUS T stage (P = 0.0002) and adjuvant hormonal therapy (P = 0.015) were found to be independent prognostic factors. For time to CBF using the Houston definition of biochemical failure, univariable analysis revealed that PSA (P = 0.001), Gleason score (P = 0.026) and prostate volume (P = 0.013) were statistically significant prognostic factors. On multivariable analysis, PSA (P = 0.002), Gleason score (P = 0.012), and adjuvant hormonal therapy (P = 0.041) were found to be independent prognostic factors. TRUS T staging was not found to be independently significant.

CONCLUSIONS

A clear role for TRUS staging as an independent prognostic factor, in the setting of other more established variables, such as Gleason grade, PSA, and digital rectal examination (DRE) T stage, was not confirmed in this study, population.

Do all patients with high-grade prostatic intraepithelial neoplasia on initial prostatic biopsy eventually progress to clinical prostate cancer?

OBJECTIVE

To assess the clinical outcome of patients with a diagnosis of high-grade prostatic intraepithelial neoplasia (PIN) on initial prostatic biopsy, with a minimum of 5 years of follow-up, as such patients are at greater risk of having prostate cancer on subsequent biopsy.

PATIENTS AND METHODS

Between November 1992 and October 1998, 21 patients were identified as having PIN on their initial transrectal ultrasonography-guided prostate biopsy. None of these patients had a focus of cancer on the initial biopsy. Their medical data were reviewed retrospectively to determine the natural history of PIN in these patients. Patients who were not identified as having cancer were followed every 6-12 months with prostate-specific antigen (PSA) testing and digital rectal examinations (DRE).

RESULTS

A mean (range) of 7 (2-8) cores were taken at initial biopsy; the mean age of the patients was 63 (53-77) years and mean PSA level 9.1 (4.9-17.6) ng/mL. Six patients had an abnormal DRE at presentation. A mean of 8 (7-10) cores were obtained on the second biopsy; six patients were diagnosed with cancer, with a mean Gleason score of 6 (5-7), while three were diagnosed with persistent PIN. These three patients had a third prostate biopsy which showed cancer of Gleason score 6 in one and benign prostatic hyperplasia in two. After a mean follow-up of 72.2 (60-84) months, none of the remaining 12 patients was diagnosed with clinically significant cancer. Five of these patients went on to a third prostate biopsy, with no evidence of cancer. One patient died from unrelated causes during this period.

CONCLUSION

This study affirms our current practice of following patients with PIN conservatively if a second or third subsequent prostate biopsy is negative. Whether PIN is a premalignant lesion or merely a lesion associated with cancer needs to be addressed in multicentre studies with a follow-up of > 10 years.

Vascular endothelial growth factor in diabetes induced early retinal abnormalities

Increased vascular permeability and blood flow alterations are characteristic features of diabetic retinal microangiopathy. The present study investigated vascular endothelial growth factor (VEGF) and its interactions with endothelin (ET) 1 and 3, endothelial, and inducible nitric oxide synthase (eNOS, iNOS) in mediating diabetes induced retinal vascular dysfunction. Male Sprague Dawley rats with streptozotocin (STZ) induced diabetes, with or without VEGF receptor signal inhibitor SU5416 treatment (high or low dose) were investigated after 4 weeks of follow-up. Colour Doppler ultrasound of the ophthalmic/central retinal artery, retinal tissue analysis with competitive RT-PCR and microvascular permeability were studied. Diabetes caused increased microvascular permeability along with increased VEGF mRNA expression. Increased vascular permeability was prevented by SU5416 treatment. Diabetic animals showed higher resistivity index (RI), indicative of vasoconstriction with increased ET-1 and ET-3 mRNA expression, whereas eNOS and iNOS mRNA expressions were un-affected. SU5416 treatment corrected increased RI via increased iNOS in spite of increased ET-1, ET-3 and VEGF mRNA expression. Cell culture (HUVEC) studies indicate that in part, an SU5416 induced iNOS upregulation may be mediated though a MAP kinase signalling pathway. The present data suggest VEGF is important in mediating both vasoconstriction and permeability in the retina in early diabetes.

Prospective evaluation of the role of quantitative Doppler ultrasound surveillance in liver transplantation

Doppler ultrasound (DUS) is able to measure parameters of blood flow within vessels of transplanted organs, and vascular complications are associated with abnormal values. We analyzed the findings of 51 consecutive patients who underwent DUS on 2 occasions in the first postoperative week following liver transplantation for cirrhosis to determine the range of values in patients following liver transplantation. Three patients developed early vascular thromboses that were detected by the absence of a Doppler signal. In patients making an uneventful recovery, the arterial velocity tended to increase and the resistive index (RI) to decrease during the first postoperative week. All recipients were shown to have high-velocity segments within the hepatic artery, without an increase in flow resistance. Assessment of the portal vein revealed narrowing at the anastomosis, associated with a segmental doubling of flow velocity, and the mean portal venous flow decreased by approximately 20% in the first postoperative week. In conclusion, a wide range of abnormalities occurs in the vessels of liver transplant recipients, which were not associated with the development of vascular complications or affect patient management.

A novel follicle culture system markedly increases follicle volume, cell number and oestradiol secretion

This study reports a novel, simple method for culture of mouse follicles which results in follicles with cell numbers similar toin vivofully grown follicles. Using this method, follicles (180–240 μm in diameter) were cultured in a 100 μl inverted drop of medium without oil and compared with culture in upright drops with and without a mineral oil overlay. Follicles, isolated from C57BL/6 × CBA/ca crossbred and MF1 inbred mice, were cultured individually at 37 °C in 96-well round-bottomed suspension cell tissue culture plates for 6 days. Follicles grown in the inverted drop culture system reached a markedly higher final diameter (means±s.e.m.; 471 ± 6.0 μm) as compared with the upright with oil (363 ± 2.7 μm) and without oil (358 ± 4.0) systems. There was no significant effect of mouse strain on follicle diameter. Follicular secretion of oestradiol and lactate into the medium was measured on days 2, 4 and 6 of culture. Secretion of oestradiol per follicle on day 6 was 2.49 ± 0.45 ng in the inverted and 0.90 ± 0.17 ng in the upright without oil system (P< 0.001). Follicular secretion of lactate on a per unit of follicle volume basis remained constant in the inverted system over days 2, 4 and 6 and was less (P< 0.001) than secretion in both the upright with and without oil systems. Follicle cell proliferation was markedly increased in the inverted as compared with the upright with oil system; the increases in cell numbers were significant on day 3 (P< 0.01) and on all subsequent days (P< 0.001). These results are discussed in relation to the supply of oxygen to the follicle in culture.

Robot-assisted 3D-TRUS guided prostate brachytherapy: System integration and validation

Current transperineal prostate brachytherapy uses transrectal ultrasound (TRUS) guidance and a template at a fixed position to guide needles along parallel trajectories. However, pubic arch interference (PAI) with the implant path obstructs part of the prostate from being targeted by the brachytherapy needles along parallel trajectories. To solve the PAI problem, some investigators have explored other insertion trajectories than parallel, i.e., oblique. However, parallel trajectory constraints in current brachytherapy procedure do not allow oblique insertion. In this paper, we describe a robot-assisted, three-dimensional (3D) TRUS guided approach to solve this problem. Our prototype consists of a commercial robot, and a 3D TRUS imaging system including an ultrasound machine, image acquisition apparatus and 3D TRUS image reconstruction, and display software. In our approach, we use the robot as a movable needle guide, i.e., the robot positions the needle before insertion, but the physician inserts the needle into the patient's prostate. In a later phase of our work, we will include robot insertion. By unifying the robot, ultrasound transducer, and the 3D TRUS image coordinate systems, the position of the template hole can be accurately related to 3D TRUS image coordinate system, allowing accurate and consistent insertion of the needle via the template hole into the targeted position in the prostate. The unification of the various coordinate systems includes two steps, i.e., 3D image calibration and robot calibration. Our testing of the system showed that the needle placement accuracy of the robot system at the "patient's" skin position was 0.15 mm+/-0.06 mm, and the mean needle angulation error was 0.07 degrees. The fiducial localization error (FLE) in localizing the intersections of the nylon strings for image calibration was 0.13 mm, and the FLE in localizing the divots for robot calibration was 0.37 mm. The fiducial registration error for image calibration was 0.12 mm and 0.52 mm for robot calibration. The target registration error for image calibration was 0.23 mm, and 0.68 mm for robot calibration. Evaluation of the complete system showed that needles can be used to target positions in agar phantoms with a mean error of 0.79 mm+/-0.32 mm.

The role of the sodium hydrogen exchanger-1 in mediating diabetes-induced changes in the retina

BACKGROUND

The sodium hydrogen exchanger (NHE) is a transmembrane protein responsible for alkalinization and control of intracellular acidosis by the removal of hydrogen and the subsequent influx of sodium. Our investigation attempts to determine the role of NHE-1 in the pathogenesis of early retinal microangiopathy due to diabetes.

METHODS

Diabetes was induced in male Sprague-Dawley rats with a single intravenous streptozotocin injection (65 mg/kg). To examine the duration-dependent changes in NHE-1 expression, retinas from 1-, 6- and 12-week diabetic animals were analyzed. To examine the functional consequences of NHE-1 inhibition in comparison with good blood glucose control, diabetic rats were randomly assigned to poorly controlled diabetic, well-controlled diabetic, poorly controlled diabetic with cariporide groups and were compared with nondiabetic controls after six weeks. Cariporide is an orally active inhibitor of NHE-1 (6000 ppm in rat chow). At the end of the treatment period, color Doppler ultrasound was used to determine the resistivity index (RI) of the central retinal artery. The mRNA expression of endothelin (ET) isoforms 1 and 3, inducible and endothelial nitric oxide synthase (iNOS and eNOS respectively) and NHE-1 were examined. NHE-1 distribution was localized with immunohistochemistry.

RESULTS

All diabetic animals showed hyperglycemia, increased glycated hemoglobin and lower body weight gain compared to nondiabetic controls. Diabetes caused an increased RI, indicative of retinal vasoconstriction, which was corrected by both cariporide treatment and good glucose control. NHE-1 was localized in the endothelium of the retinal microvasculature and the neuronal and glial components. NHE-1 mRNA expression was unchanged after 1 week and increased after 6 and 12 weeks of diabetes. Furthermore, a diabetes-induced upregulation of ET-1 and ET-3 mRNA expression after six weeks was corrected with cariporide treatment. NHE-1 inhibition of diabetic animals upregulated iNOS mRNA levels, although expression of eNOS and iNOS mRNA were not altered in poorly controlled diabetes. Improved blood glucose control with higher doses of insulin also corrected diabetes-induced increased RI by upregulating eNOS and iNOS mRNA expression.

CONCLUSIONS

The results of the study suggest that NHE-1 may be involved in the regulation of several vasoactive modulators that contribute to functional alterations in diabetic retinal microangiopathy.