Low-tube-voltage whole-body CT angiography with extremely low iodine dose: a comparison between hybrid-iterative reconstruction and deep-learning image-reconstruction algorithms

AIM

To evaluate arterial enhancement, its depiction, and image quality in low-tube potential whole-body computed tomography (CT) angiography (CTA) with extremely low iodine dose and compare the results with those obtained by hybrid-iterative reconstruction (IR) and deep-learning image-reconstruction (DLIR) methods.

MATERIALS AND METHODS

This prospective study included 34 consecutive participants (27 men; mean age, 74.2 years) who underwent whole-body CTA at 80 kVp for evaluating aortic diseases between January and July 2020. Contrast material (240 mg iodine/ml) with simultaneous administration of its quarter volume of saline, which corresponded to 192 mg iodine/ml, was administered. CT raw data were reconstructed using adaptive statistical IR-Veo of 40% (hybrid-IR), DLIR with medium- (DLIR-M), and high-strength level (DLIR-H). A radiologist measured CT attenuation of the arteries and background noise, and the signal-to-noise ratio (SNR) was then calculated. Two reviewers qualitatively evaluated the arterial depictions and diagnostic acceptability on axial, multiplanar-reformatted (MPR), and volume-rendered (VR) images.

RESULTS

Mean contrast material volume and iodine weight administered were 64.1 ml and 15.4 g, respectively. The SNRs of the arteries were significantly higher in the following order of the DLIR-H, DLIR-M, and hybrid-IR (p<0.001). Depictions of six arteries on axial, three arteries on MPR, and four arteries on VR images were significantly superior in the DLIR-M or hybrid-IR than in the DLIR-H (p≤0.009 for each). Diagnostic acceptability was significantly better in the DLIR-M and DLIR-H than in the hybrid-IR (p<0.001-0.005).

CONCLUSION

DLIR-M showed well-balanced arterial depictions and image quality compared with the hybrid-IR and DLIR-H.

Effect of X-ray tube on image quality and pancreatic ductal adenocarcinoma conspicuity in pancreatic protocol dual-energy CT

AIM

To compare the radiation dose, image quality, and conspicuity of pancreatic ductal adenocarcinoma (PDAC) in pancreatic protocol dual-energy computed tomography (CT) between two X-ray tubes mounted in the same CT machine.

MATERIAL AND METHODS

This retrospective study comprised 80 patients (median age, 73 years; 45 men) who underwent pancreatic protocol dual-energy CT from January 2019 to March 2022 using either old (Group A, n=41) or new (Group B, n=39) X-ray tubes mounted in the same CT machine. The imaging parameters were completely matched between the two groups, and CT data were reconstructed at 70 and 40 keV. The CT dose-index volume (CTDIvol); CT attenuation of the abdominal aorta, pancreas, and PDAC; background noise; and qualitative scores for the image noise, overall image quality, and PDAC conspicuity were compared between the two groups.

RESULTS

The CTDIvol was lower in Group B than Group A (7.9 versus 9.2 mGy; p<0.001). The CT attenuation of all anatomical structures at 70 and 40 keV was comparable between the two groups (p=0.06-0.78). The background noise was lower in Group B than Group A (12 versus 14 HU at 70 keV, p=0.046; and 26 versus 30 HU at 40 keV, p<0.001). Qualitative scores for image noise and overall image quality at 70 and 40 keV and PDAC conspicuity at 40 keV were higher in Group B than Group A (p<0.001-0.045).

CONCLUSION

The latest X-ray tube could reduce the radiation dose and improve image quality in pancreatic protocol dual-energy CT.

A case of functional visual loss diagnosed through bilateral randomized visual field testing with a trick method

Purpose

To report a case of functional visual loss (FVL) diagnosed through bilateral randomized visual field testing using Imo vifa with a trick method.

Observations

A 27-year-old man complained of visual field abnormality in his left eye after falling from a height of 4 m. The left eye had a best-corrected visual acuity (BCVA) of 20/16 and a critical flicker frequency (CFF) of 44.5 Hz at the first visit. Commotio retinae was observed in the inferior retina of the left eye, and the pupillary light reflex was normal. Computed tomography and magnetic resonance imaging of the head revealed no abnormalities. However, the Goldmann perimeter (GP) showed constriction of visual field in the left eye. Since traumatic optic neuropathy was suspected initially; therefore, two courses of methylprednisolone pulse therapy were administered. However, the BCVA and CFF gradually worsened to 20/200 and 14 Hz, respectively. Nevertheless, his pupillary light reflex was still normal, and GP showed a spiral visual field. Thus, we suspected that this was a case of FVL and performed bilateral randomized visual field testing using Imo vifa in three steps as a trick method. In the first step, we performed the normal method for bilateral randomized visual field testing. In the second and third steps, we explained to the patient that only the right or left eye would be examined on purpose; bilateral randomized visual field testing was then performed. The results of examinations revealed left homonymous hemianopsias and normal and concentric contraction of the visual field in both eyes. These results could not be explained by organic disease, and the patient was diagnosed with FVL.

Conclusions and Importance

Bilateral randomized visual field testing using Imo vifa with a trick method was useful for diagnosing FVL.

SUBRETINAL ENDOSCOPIC SURGERY FOR METASTATIC CHOROIDAL TUMOR

PURPOSE

To report a case of a metastatic choroidal tumor treated with subretinal endoscopic surgery.

METHODS

A single case report.

RESULTS

A 68-year-old woman presented with a metastatic choroidal tumor in the right eye and an intraocular pressure of 54 mmHg. Chemotherapy and radiotherapy were ineffective in eliminating her eye pain. Subretinal endoscopic surgery was performed to remove the metastatic choroidal tumor with the complex retinal detachment attached to the posterior surface of the lens. The day after subretinal endoscopic surgery, the patient's intraocular pressure decreased to 7 mmHg and her pain subsided. The chemotherapeutic strategy was modified according to the pathological findings. Survival prognosis improved from 3 to 18 months. Twenty-one months after the surgery, the retinal detachment was reattached under silicone oil with a best-corrected visual acuity of 20/1,000 and an intraocular pressure of 15 mmHg.

CONCLUSION

In this case, subretinal endoscopic surgery preserved visual function, eliminating the need for enucleation.

Treatment of old submacular hemorrhage by subretinal endoscopic surgery and intraoperative subretinal endoscopic findings

Purpose

We report a case of old submacular hemorrhage (SMH) due to polypoidal choroidal vasculopathy (PCV). Subretinal endoscopic surgery (SES) was performed, which improved visual function. In addition, we show the intraoperative findings of subretinal aberrant PCV vessels as seen under endoscopic observation, which cannot be observed by microscopic surgery.

Observations

A 71-year-old Japanese man presented with an old dehemoglobinized SMH due to PCV in his left eye. At the time of presentation, three weeks had already passed after the onset of the patient's symptoms, and the best-corrected visual acuity (BCVA) was 20/200. SES was performed to remove the SMH and treat the subretinal PCV lesions. After creating retinal detachment using a 38-gauge cannula, three subretinal 25-gauge trocars were inserted from the sclera to the subretinal space. Then, SES was performed under ophthalmic endoscopic observation with continued subretinal irrigation for maintaining the retinal detachment. After removal of the SMH, subretinal polyp-shaped nodular vascular lesions (polyps) and a branching vascular network, which is located inside the retinal pigmented epithelium, were identified. The sites that presumably originated from the aberrant vessels of the PCV and the associated polyps were coagulated using endodiathermy. After the subretinal procedure, the retina was flattened with fluid/air exchange, and silicone oil (SO) was injected into the vitreous cavity. The SMH completely disappeared after surgery. Although at one-month follow-up BCVA (20/250) was slightly worse than that before surgery, there was an improvement in postoperative retinal sensitivity in the macula compared to that before surgery. At the three-month follow-up, the SO was removed. The BCVA was 20/200 one month after SO removal. No postoperative complications occurred. Additional treatment was not required, including anti-vascular endothelial growth factor therapy, for PCV progression or SMH recurrence in the left eye till the final visit two years after surgery.

Conclusion and importance

SES could effectively remove the old SMH, and the activity of PCV was suppressed by intraoperative subretinal coagulation. The retinal sensitivity of the macula improved after the SES. In addition, we observed subretinal polyps and a branching vascular network located internal to the retinal pigmented epithelium under intraoperative subretinal endoscopic observation. SES is a good surgical option for the removal of old SMH or treatment of subretinal lesions.

Deep-learning image-reconstruction algorithm for dual-energy CT angiography with reduced iodine dose: preliminary results

AIM

To evaluate the computed tomography (CT) attenuation values, background noise, arterial depiction, and image quality in whole-body dual-energy CT angiography (DECTA) at 40 keV with a reduced iodine dose using deep-learning image reconstruction (DLIR) and compare them with hybrid iterative reconstruction (IR).

MATERIAL AND METHODS

Whole-body DECTA with a reduced iodine dose (200 mg iodine/kg) was performed in 22 patients, and DECTA data at 1.25-mm section thickness with 50% overlap were reconstructed at 40 keV using 40% adaptive statistical iterative reconstruction with Veo (hybrid-IR group), and DLIR at medium and high levels (DLIR-M and DLIR-H groups). The CT attenuation values of the thoracic and abdominal aortas and iliac artery and background noise were measured. Arterial depiction and image quality on axial, multiplanar reformatted (MPR), and volume-rendered (VR) images were assessed by two readers. Quantitative and qualitative parameters were compared between the hybrid-IR, DLIR-M, and DLIR-H groups.

RESULTS

The vascular CT attenuation values were almost comparable between the three groups (p=0.013-0.97), but the background noise was significantly lower in the DLIR-H group than in the hybrid-IR and DLIR-M groups (p<0.001). The arterial depictions on axial and MPR images and in almost all arteries on VR images were comparable (p=0.14-1). The image quality of axial, MPR, and VR images was significantly better in the DLIR-H group (p<0.001-0.015).

CONCLUSION

DLIR significantly reduced background noise and improved image quality in DECTA at 40 keV compared with hybrid-IR, while maintaining the arterial depiction in almost all arteries.

Deep-learning-based image reconstruction in dynamic contrast-enhanced abdominal CT: image quality and lesion detection among reconstruction strength levels

AIM

To evaluate the use of deep-learning-based image reconstruction (DLIR) algorithms in dynamic contrast-enhanced computed tomography (CT) of the abdomen, and to compare the image quality and lesion conspicuity among the reconstruction strength levels.

MATERIALS AND METHODS

This prospective study included 59 patients with 373 hepatic lesions who underwent dynamic contrast-enhanced CT of the abdomen. All images were reconstructed using four reconstruction algorithms, including 40% adaptive statistical iterative reconstruction-Veo (ASiR-V) and DLIR at low, medium, and high-strength levels (DLIR-L, DLIR-M, and DLIR-H, respectively). The signal-to-noise ratio (SNR) of the abdominal aorta, portal vein, liver, pancreas, and spleen and the lesion-to-liver contrast-to-noise ratio (CNR) were calculated and compared among the four reconstruction algorithms. The diagnostic acceptability was qualitatively assessed and compared among the four reconstruction algorithms and the conspicuity of hepatic lesions was compared between <5 and ≥5 mm lesions.

RESULTS

The SNR of each anatomical structure (p<0.0001) and CNR (p<0.0001) were significantly higher in DLIR-H than the other reconstruction algorithms. Diagnostic acceptability was significantly better in DLIR-M than the other reconstruction algorithms (p<0.0001). The conspicuity of hepatic lesions was highest when using 40% ASiR-V and tended to lessen as the reconstruction strength level was getting higher in DLIR, especially in <5 mm lesions; however, all hepatic lesions could be detected.

CONCLUSIONS

DLIR improved the SNR, CNR, and image quality compared with 40% ASiR-V, while making it possible to decrease lesion conspicuity using higher reconstruction strength.

Evaluation of Axial Length Measurement Using Enhanced Retina Visualization Mode of the Swept-Source Optical Coherence Tomography Biometer in Dense Cataract

INTRODUCTION

It has been reported that even using the swept-source (SS) optical coherence biometer, it is challenging to measure the axial length (AL) in cases with advanced cataracts. The enhanced retina visualization (ERV) mode, which is equipped with OCTB1 (ARGOS), shifts the peak of measurement sensitivity to the retinal side so that the AL can be measured even if the light energy is attenuated. The aim of the present study was to evaluate the accuracy and efficacy of the ERV mode in measuring the AL of dense cataracts.

METHODS

This was a single-center retrospective observational case series conducted in Japan. We included 213 eyes of 213 consecutive patients with advanced cataracts who underwent preoperative evaluation. The AL was measured before and after surgery using two SS optical coherence tomography biometers (OCTB1 and OCTB2; IOLMaster 700). Cases in which OCTB1 the standard mode failed to measure AL, OCTB1 with the ERV mode was used instead. Primary outcome measures were the acquisition rate and the AL measurement accuracy using the ERV mode. The χ2 test, the Kruskal-Wallis test, and the Wilcoxon signed-rank test were used to compare the acquisition rate and differences between pre- and postoperative AL values, respectively. In the ERV subgroup, Bland-Altman plots were used to compare the pre- and postoperative AL values measured using OCTB1-ERV mode. A p-value of less than 5% was considered statistically significant.

RESULTS

The AL acquisition rate was not significantly different between OCTB1 with the standard mode and OCTB2. The AL of 65 eyes (30.5%) could not be measured using OCTB1 with the standard mode. Conversely, the AL of 51 of these eyes (78.5%) was successfully measured using OCTB1 with the ERV mode. In these 51 eyes, a difference of ≤0.2 mm and of ≤0.1 mm between pre- and postoperative AL measurements was observed in 40 (78.4%) and 30 eyes (58.8%), respectively. The Bland-Altman plot found no systematic error between pre- and postoperative AL values measured using the ERV mode.

CONCLUSION

In patients with dense cataracts, AL measurement using the standard mode of an SS-OCT biometer is challenging. Furthermore, the ERV mode could be promising for AL measurement in such cases.

Comparison of Clinical Outcomes Between Intracapsular Implantation and Intrascleral Fixation Using the Same Model of Intraocular Lens

Purpose

To compare the clinical outcomes of intrascleral intraocular lens (IOL) fixation surgery with those of intracapsular IOL implantation in conventional cataract surgery.

Patients and Methods

Twenty-one eyes of 21 consecutive patients who underwent intrascleral IOL fixation (SF group) and 21 eyes of 21 patients who underwent IOL intracapsular implantation during cataract surgery (IN group) were retrospectively enrolled. For both groups, the same model of IOL was used in all cases. For all cases in the SF group, Yamane’s double-needle technique was performed.

Results

The mean corrected visual acuity (logMAR) after surgery was significantly better in the IN than in the SF group (−0.063 ± 0.12 vs 0.05 ± 0.14; p = 0.0083). The mean anterior chamber depth after surgery was significantly smaller in the IN than in the SF group (4.65 ± 0.23 mm vs 4.98 ± 0.61 mm; p = 0.0231). The amounts of tilt and decentration were also significantly smaller in the IN group (5.21°± 1.47° and 0.22 ± 0.13 mm, respectively, vs 8.8° ± 3.9° and 0.52 ± 0.35 mm, respectively; p = 0.0003 and p = 0.0007). The mean absolute refractive prediction error was significantly smaller in the IN than in the SF group (0.22 ± 0.17 D vs 0.86 ± 0.59 D; p = 0.0002).

Conclusion

The intrascleral IOL fixation surgery proved to be highly effective. However, its clinical outcomes were slightly inferior to those of IOL intracapsular implantation, and further improvement of this surgical technique may be needed.

A case of severe choroidal detachment in both eyes due to systemic lupus erythematosus

Purpose

We report a case of severe choroidal detachments (CDs) in both eyes caused by systemic lupus erythematosus (SLE).

Observations

The patient was a 50-year-old woman who presented with conjunctival edema in both eyes, visual dysfunction, and generalized fatigue. At the first visit, the best corrected visual acuity (BCVA) was 20/70 OD and 20/70 OS, and the intraocular pressure (IOP) was 22 mmHg OD and 27 mmHg OS. She had serous retinal detachments (SRDs), CDs, ciliary dissections, and a shallow anterior chamber with partial angle closure in both eyes. Systemic findings included hypoalbuminemia, pleural fluid, generalized fatigue, and brown papules on the back and both legs. First, we suspected Vogt-Koyanagi-Harada disease and administered two courses of methylprednisolone pulse therapy, but the CDs in both eyes gradually deteriorated and worsened to the extent that the optic nerve in both eyes could not be observed, and the BCVA deteriorated to 20/200 OD and 6/200 OS. Further multidisciplinary evaluations for diagnosing collagen diseases revealed vasculitis in the skin histopathology examination, positive results for anti-double stranded DNA antibody and anti-SS-A antibody, and hypocomplementemia in the blood examination, and she was diagnosed with severe SLE in the dermatology department. After administration of high dose intravenous γ-globulin therapy, albumin infusion, and intravenous cyclophosphamide pulse therapy, the SRDs and severe CDs improved along with improvement in hypoalbuminemia, pleural fluid, and generalized fatigue. Moreover, the shallow anterior chamber and high IOP improved to normal in both eyes. The CDs and SRDs completely disappeared, and the BCVA improved to 20/13 OU 6 months after the SLE therapy.

Conclusion and importance

In patients with observed SRDs and CDs accompanying hypoalbuminemia, it is necessary to consider collagen diseases such as SLE.

[Clinical Outcomes of Endoscope-Assisted 30-Gauge Single-Needle Technique for Intrascleral Intraocular Lens Fixation]

INTRODUCTION

We have developed an endoscope-assisted single-needle technique, which is an improvement of Yamane's double-needle technique of the intrascleral intraocular lens (IOL) fixation techniques. In this surgical procedure, the IOL is manipulated in the vitreous cavity, and the IOL haptic is externalized from the eye one by one with the aid of an ophthalmic endoscope. The purpose of this study was to report the postoperative visual function and safety of this new technique.

METHODS

Overall, 19 consecutive eyes (16 patients; mean age, 75.1 ± 9.6 years; mean follow-up period, 5.7 months) that underwent intrascleral IOL fixation surgery with our new technique were included in the study. Manifest refraction, uncorrected/corrected visual acuity, and corneal endothelial cell density were measured before and after surgery. Tilt and decentration of IOL were analyzed using anterior segment optical coherence tomography.

RESULTS

The mean absolute prediction error (spherical equivalent) was 0.82 ± 0.52. The mean postoperative best-corrected visual acuity had significantly improved at the final visits (p = 0.02). No significant differences in the mean corneal endothelial cell density were observed between the first (2,232 ± 751 cells/mm2) and final (2,099 ± 649 cells/mm2) visits (p = 0.35). The mean IOL tilt was 8.1 ± 3.2°. There were no vision-threatening complications, such as retinal detachment, endophthalmitis, or IOL dislocation, during or after surgery.

CONCLUSIONS

The endoscope-assisted single-needle technique is a safe and effective method of intrascleral IOL fixation surgery.

Prediction of Effective Lens Position Using Multiobjective Evolutionary Algorithm

Purpose

The purpose of this study was to evaluate the prediction accuracy of effective lens position (ELP) after cataract surgery using a multiobjective evolutionary algorithm (MOEA).

Methods

Ninety-six eyes of 96 consecutive patients (aged 73.9 ± 8.6 years) who underwent cataract surgery were retrospectively studied; the eyes were randomly distributed to a prediction group (55 eyes) and a verification group (41 eyes). The procedure was repeated randomly 30 times to create 30 data sets for both groups. In the prediction group, based on the parameters of preoperative optical coherence tomography (OCT), biometry, and anterior segment (AS)-OCT, the prediction equation of ELP was created using MOEA and stepwise multiple regression analysis (SMR). Subsequently, the prediction accuracy of ELPs was evaluated and compared with conventional formulas, including SRK/T and the Haigis formula.

Results

The rate of mean absolute prediction error of 0.3 mm or higher was significantly lower in MOEA (mean 4.9% ± 3.2%, maximum 9.8%) than SMR (mean 7.3% ± 4.8%, maximum 24.4%) (P = 0.0323). The median of the correlation coefficient (R² = 0.771) between the MOEA predicted and measured ELP was higher than the SRK/T (R² = 0.412) and Haigis (R² = 0.438) formulas.

Conclusions

The study demonstrated that ELP prediction by MOEA was more accurate and was a method of less fluctuation than that of SMR and conventional formulas.

Translational Relevance

MOEA is a promising method for solving clinical problems such as prediction of ocular biometry values by simultaneously optimizing several conditions for subjects affected by various complex factors.

Clinical outcomes of endoscope-assisted vitrectomy for treatment of rhegmatogenous retinal detachment

Summary

We evaluated the clinical outcomes for ophthalmic endoscope-assisted vitrectomy in consecutive patients with uncomplicated rhegmatogenous retinal detachment (RRD). The primary success rate was 98.4% (125/127) without performing a posterior drainage retinotomy or using perfluorocarbon liquids (PFCL) for subretinal fluid drainage.

Purpose

To investigate the clinical outcomes of endoscope-assisted vitrectomy in patients with uncomplicated RRD.

Methods

We examined 127 eyes from consecutive patients who underwent repair of RRD by 23- or 25-gauge endoscope-assisted vitrectomy, with a minimum follow-up of 3 months. Eyes with the following criteria were excluded: Giant retinal tears, grade C proliferative vitreoretinopathy, dense vitreous hemorrhage, retinal detachment secondary to other ocular diseases, and prior retinal or vitreous surgery. All cases underwent subretinal fluid drainage, endolaser photocoagulation and fundus inspection were performed under ophthalmic endoscopic observation. Success rate, visual acuity, surgery time and complications were evaluated.

Results

Primary and final success rate was 98.4% (125/127) and 100% (127/127), respectively, Surgery time was 59.6±26.3 minutes. The best-corrected visual acuity significantly improved from 20/100 to 20/20 (P<0.0001). There were 2 cases (1.6%) of creation of a peripheral drainage retinotomy and 4 cases (3.1%) of using PFCL to suppress movement of the detached retina, but there were no cases of creation of a posterior drainage retinotomy or using PFCL for subretinal fluid drainage. There was 1 case of presumed endophthalmitis after surgery. There were 12 hypotonous cases at postoperative day 1 and one of them needed additional scleral sutures at postoperative day 4 for prolonged hypotony.

Conclusion

The present study demonstrated the efficacy of endoscope-assisted vitrectomy for patients with uncomplicated RRD. To perform endoscope-assisted vitrectomy safely, sufficient closure of sclerotomies is necessary at the end of surgery.

Experimental Study on Self-organized and Error Resistant Control of Distributed Autonomous Robotic Systems

The assignment of distributed mobile autonomous robots to targets, which occurs for instance as an important task in flexible manufacturing environments, is solved by using a self-organization approach motivated by pattern formation principles in biological, chemical, and physical systems. Similar to observations in many natural systems, such as ant tribes, the pattern formation of colored shells or convection patterns in the Rayleigh-Bénard problem of fluid dynamics, the self-organization principles lead to a robust and fault tolerant behavior where the patterns or structures recover from disturbances. The considered problem is the dynamic assignment of a number of robots to given targets where the mobile robots have to move to the targets in order to perform some tasks there. Hereby, each robot uses only local information (i.e., no world coordinate system is necessary). The underlying mathematical problem of the robot-target assignment is the so-called two-index assignment problem from combinatorial optimization. The approach used guarantees always feasible solutions in the assignment of robotic units to targets. As a consequence, for scenarios with only convex obstacles with large enough distances to each other, no spurious states cause the assignment process to fail. The error resistant control method for distributed autonomous robotic systems is demonstrated by several experiments with mobile robots. These results are compared and supplemented with computer simulations.

Increased internal higher-order aberrations as a useful parameter for indication of vitrectomy in three asteroid hyalosis cases

We report three asteroid hyalosis cases in which internal higher-order aberrations (HOAs) were improved concomitant with improved visual symptoms after vitrectomy. Cases 1 and 2 reported severe floaters and glare disability, although their visual acuities were fairly good. Case 3 showed poor visual acuity since this patient also suffered from mild macular degeneration. For these three asteroid hyalosis cases, we were unsure if treatment with vitrectomy could improve visual symptoms. Therefore, we measured internal HOAs with an aberrometer, and found that the internal HOA values in these cases were high. We suspected that internal high HOAs values were associated with visual disturbance, and performed vitrectomy. After the vitrectomy, the internal HOA values in these three asteroid hyalosis cases markedly decreased, and visual symptoms improved. These observations suggested that measurement of internal HOAs may be useful to determine the indication for vitrectomy.

[Comparison of central visual field visualization while using a combination of spherical intraocular lenses with vitreous contact lenses]

OBJECTIVE

To investigate intraocular lens (IOL) and vitreous contact lens (VCL) combinations that provide good central visual field visualization in vitreous surgery.

METHOD

ZEMAX optical design software was used to perform optical simulations using the ray tracing method on a Gullstrand eye model. The implanted IOL was assumed to consist of material with a refractive index of 1.550 (high refractive index acrylic IOL), 1.470 (low refractive index acrylic IOL) and 1.413 (silicon IOL), and was set as a biconvex spherical lens (optical diameter 6 mm, 23.5 D). The VCL was assumed to have a refractive index of 1.900 (HEMA VCL), 1.490 (PMMA VCL) and 1.413 (silicon VCL), and was set as a concave lens (optical diameter 10 mm) with a flat anterior surface and a posterior surface with a radius of curvature of 7.70 mm. The spherical aberration of the overall optical system, including the IOL-implanted eyeball and the VCL, was calculated.

RESULTS

Spherical aberration was lowest with the silicon VCL for the high refractive index acrylic IOL and with the PMMA VCL for the low refractive index acrylic and silicon IOLs.

CONCLUSION

The combinations providing the best central visual field visualization in vitreous surgery are a silicon VCL for implantation of a high refractive index acrylic IOL and a PMMA VCL for implantation of a low refractive index acrylic or silicon IOL.

The role of transient receptor potential vanilloid-1 on neural responses to acids by the chorda tympani, glossopharyngeal and superior laryngeal nerves in mice

The transient receptor potential vanilloid-1 (TRPV1) receptor acts as a polymodal nociceptor activated by capsaicin, heat, and acid. TRPV1, which is expressed in sensory neurons innervating the oral cavity, is associated with an oral burning sensation in response to spicy food containing capsaicin. However, little is known about the involvement of TRPV1 in responses to acid stimuli in either the gustatory system or the general somatosensory innervation of the oropharynx. To test this possibility, we recorded electrophysiological responses to several acids (acetic acid, citric acid and HCl) and other taste stimuli from the mouse chorda tympani, glossopharyngeal and superior laryngeal nerves, and compared potential effects of iodo-resiniferatoxin (I-RTX), a potent TRPV1 antagonist, on chemical responses of the three nerves. The results indicated that in the chorda tympani nerve, I-RTX (1-100 nM) did not affect responses to acids, sucrose and quinine HCl, but reduced responses to NaCl (I-RTX at concentrations of 10 and 100 nM) and KCl and NH(4)Cl (100 nM). In contrast, in the glossopharyngeal nerve, I-RTX significantly suppressed responses to all acids and salts, but not to sucrose and quinine HCl. Responses to acetic acid were suppressed by I-RTX even at 0.1 nM concentration. The superior laryngeal nerve responded in a concentration-dependent manner to acetic acid, citric acid, HCl, KCl, NH(4)Cl and monosodium l-glutamate. The responses to acetic acid, but not to the other stimuli, were significantly inhibited by I-RTX. These results suggested that TRPV1 may be involved in the mechanism for responses to acids presented to the posterior oral cavity and larynx. This high degree of responsiveness to acetic acid may account for the oral burning sensation, known as a flavor characteristic of vinegar.

Clinical evaluation of the arched blade for cataract surgery

PURPOSE

To evaluate the efficacy of the arched blade for making clear corneal incisions in cataract surgery.

METHODS

This prospective study comprised 112 eyes of 74 patients scheduled for cataract surgery. Temporal clear corneal incisions were made with either a 3.2-mm conventional flat blade or the arched blade. The choice of knife was randomly assigned. Two surgeons, one with substantial cataract surgery experience and the other with less experience, performed the surgery. Corneal topography and aberration were examined pre- and postoperatively. The degree of surgically induced astigmatism (SIA) and high order aberration was analysed. The self-sealing ability of the wound was also compared between both blades.

RESULTS

For the less experienced surgeon, the degree of SIA was significantly higher with the 3.2-mm flat blade than with the 3.2-mm arched blade as measured at any time during postoperative follow-up. For the more experienced surgeon, the degree of high order aberration increased significantly with the 3.2-mm flat blade. The incision's self-sealing ability was significantly better when the wound was made with the arched blade rather than with the flat blade.

CONCLUSION

The arched blade proved to be effective in reducing surgically induced astigmatism and high order aberration in cataract surgery, particularly when used by the less experienced surgeon. Using the arched blade should lead to better wound self-sealing and, therefore, safer surgical results.

Antagonism of ghrelin receptor reduces food intake and body weight gain in mice

BACKGROUND AND AIMS

Ghrelin, an endogenous ligand for growth hormone secretagogue receptor (GHS-R), is an appetite stimulatory signal from the stomach with structural resemblance to motilin. We examined the effects of the gastric peptide ghrelin and GHS-R antagonists on energy balance and glycaemic control in mice.

MATERIALS AND METHODS

Body weight, fat mass, glucose, insulin, and gene expression of leptin, adiponectin, and resistin in white adipose tissue (WAT) were measured after repeated administrations of ghrelin under a high fat diet. Gastric ghrelin gene expression was assessed by northern blot analysis. Energy intake and gastric emptying were measured after administration of GHS-R antagonists. Repeated administration of GHS-R antagonist was continued for six days in ob/ob obese mice.

RESULTS

Ghrelin induced remarkable adiposity and worsened glycaemic control under a high fat diet. Pair feeding inhibited this effect. Ghrelin elevated leptin mRNA expression and reduced resistin mRNA expression. Gastric ghrelin mRNA expression during fasting was increased by a high fat diet. GHS-R antagonists decreased energy intake in lean mice, in mice with diet induced obesity, and in ob/ob obese mice; it also reduced the rate of gastric emptying. Repeated administration of GHS-R antagonist decreased body weight gain and improved glycaemic control in ob/ob obese mice.

CONCLUSIONS

Ghrelin appears to be closely related to excess weight gain, adiposity, and insulin resistance, particularly under a high fat diet and in the dynamic stage. Gastric peptide ghrelin and GHS-R may be promising therapeutic targets not only for anorexia-cachexia but also for obesity and type 2 diabetes, which are becoming increasingly prevalent worldwide.

Photodynamic therapy with verteporfin in mallatia leventinese

OBJECTIVE

To describe a case of a patient with documented genetic mallatia leventinese who developed a classic choroidal neovascular membrane and underwent photodynamic therapy (PDT) with verteporfin (Visudyne; CIBA Vision Corp., Duluth, GA).

DESIGN

Interventional case report.

INTERVENTION

The patient underwent a complete ophthalmologic evaluation and fluorescein angiography. Photodynamic therapy with verteporfin was performed.

MAIN OUTCOME MEASURES

Clinical and angiographic records were analyzed for evidence of changes in visual acuity, clinically evident subretinal fluid and the extent of fluorescein leakage from choroidal neovascularization (CNV).

RESULTS

Three weeks after treatment, a fluorescein angiogram showed closure of the neovascular membrane, no evident subretinal fluid was seen, and visual acuity had improved from 20/60- to 20/40. Nine weeks after the application, fluorescein angiography demonstrated a microscopic hyperfluorescent spot at the site of the previously active CNV at which a small area of shallow subretinal fluid was observed, and visual acuity was 20/50. Thirty-four weeks after PDT, visual acuity was 20/60, subretinal fluid resolved, and fluorescein angiography did not show any further changes.

CONCLUSIONS

Photodynamic therapy with verteporfin may be considered as a possible treatment in patients with mallatia leventinese who develop classic CNV.

[A role of visiting nurses in providing the terminal patients with their desirable life-discussion regarding the place of death of the patients who were registered for visiting nurse system]

AIM

To evaluate the prognosis of the patients who had visiting nurse service and discuss the place of death (life at the terminal stage). To determine the roles of visiting nurses in providing the patients at a terminal stage with their desirable life till death.

METHODS

A total of 180 patients, who were registered for their home healthcare service in our Shonan Kamakura General Hospital and died between January 2000 and February 2001, were subjected to the study. All the subjects were classified into 3 groups according to the places of their death, 1) death at home, 2) death in the hospital and 3) death upon arrival after the admission to the hospital. Moreover, the following items were also surveyed and analyzed: 1) diagnosis (name of diseases), 2) cause of death, 3) age, 4) family structure, 5) whether their primary care physicians explained the prognosis and possible expected conditions to the patients and their family before hand, and 6) how the visiting nurses interact with the patients and their family members.

RESULTS

Sixty-six patients died at home, 105 in the hospital and 9 upon arrival at the hospital. During this survey period, there were a total of 5,274 and 5,574 visits by primary care physicians and visiting nurses, respectively. The patients who died at home were more often observed in the patients whose primary care physicians explained their conditions to them and whose visiting nurses closely related to them. Moreover, the patients with malignant tumor also more often died at home. On the contrary, there were very few patients with chronic diseases, with whom death at home was accepted and agreed before hand, and there were some cases with chronic diseases who died inside of the ambulance transported on the way to the hospital after a sudden change in their conditions.

DISCUSSION AND CONCLUSION

In order to have the patients live their desirable life till their death, it is required for the caretakers to prepare their mind for the day of the patient's death in addition to the patient's own wishes. For the patients with malignant tumor, it is easy to predict their prognosis, thus the caretakers can get prepared for the day of the patient's death. On the contrary, in case of the patients with chronic diseases, it is more difficult for the caretakers to experience an indefinite time with the patients since their prognosis is generally longer but the sudden change in their conditions may give the caretakers a high anxiety. Thus, it is essential for the visiting nurses to play a role as a mediator to interact between the patients and their family members, and their primary care physicians, and to establish a trustful relationship with the patients while their conditions are still stable. Moreover, similar to the malignant patients, the visiting nurses should explain the situations to the patients with chronic diseases, that they can choose the place of their own death and specific medical treatment at emergency and can decide the detail for their terminal stage with their family members. Thus, it was considered to be very important that the visiting nurses should frequently confirm these issues with the patients and their family according to their conditions.

Cocaine-amphetamine-regulated transcript influences energy metabolism, anxiety and gastric emptying in mice

This study was designed to investigate the effects of cocaine-amphetamine-regulated transcript (CART), a recently discovered hypothalamic neuropeptide, on food intake, anxiety, oxygen consumption and gastric emptying in mice. Intracerebroventricular (i. c. v.) injection of CART (1 - 100 pmol) markedly reduced food intake in a dose-related manner. A significant decrease was observed 20 min after i. c. v. injection of CART and continued for four hours. In the elevated plus maze test, i. c. v. CART injection significantly raised the normal preference for the closed arms. Furthermore, the i. c. v. injection of CART significantly reduced oxygen consumption and gastric emptying rate. These results suggest that CART modulates feeding, emotion, and autonomic functions in mice.

A role of ghrelin in neuroendocrine and behavioral responses to stress in mice

Ghrelin, an endogenous ligand of the growth hormone secretagogue receptor, was recently identified in the rat stomach. Previous studies have shown that ghrelin potently increases growth hormone release and food intake. We examined the effects of the gastric peptide ghrelin on anxiety-like behavior in association with the hypothalamic-pituitary-adrenal axis in mice. Both intra-third cerebroventricular and intraperitoneal administration of ghrelin potently and significantly induced anxiogenic activities in the elevated plus maze test. Ghrelin gene expression in the stomach was increased by tail pinch stress as well as by starvation stress. Administration of a corticotropin-releasing hormone (CRH) receptor antagonist significantly inhibited ghrelin-induced anxiogenic effects. Peripherally administered ghrelin significantly increased CRH mRNA, but not urocortin mRNA expression in the hypothalamus. Furthermore, intraperitoneal injection of ghrelin produced a significant dose- dependent increase in serum corticosterone levels. These findings suggest that ghrelin may have a role in mediating neuroendocrine and behavioral responses to stressors and that the stomach could play an important role, not only in the regulation of appetite, but also in the regulation of anxiety.

Combined hamartoma of the retina and retinal pigment epithelium associated with juvenile nasopharyngeal angiofibroma

PURPOSE

To report a patient who had concomitant combined hamartoma of the retinal pigment epithelium and retina and juvenile nasopharyngeal angiofibroma.

METHOD

Case report.

RESULTS

An 18-year-old man presented with a juvenile nasopharyngeal angiofibroma and a combined hamartoma of the retina and retinal pigment epithelium in the ipsilateral eye. The diagnosis of juvenile nasopharyngeal angiofibroma was confirmed by histopathology, and the diagnosis of combined hamartoma was established by typical ophthalmoscopic and fluorescein angiographic findings.

CONCLUSION

Juvenile nasopharyngeal angiofibroma may be associated with combined hamartoma of the retina and retinal pigment epithelium.

Optical coherence tomography of bleb-like subretinal lesions after retinal reattachment surgery

PURPOSE

To report the optical coherence tomographic characteristics of persistent bleb-like subretinal lesions after retinal reattachment surgery, including scleral buckling and cryopexy.

METHODS

Case reports.

RESULTS

In two eyes of two patients yellow to yellowish-orange bleb-like lesions were found in the posterior pole after retinal reattachment surgery. The common aspects of the surgery were scleral buckling procedures and cryopexy. There were subretinal precipitates in some of the lesions. The lesions showed no associated leakage during fluorescein or indocyanine green angiography. Optical coherence tomography demonstrated that the bleb-like lesions were tiny retinal detachments.

CONCLUSION

Optical coherence tomography examination of bleb-like subretinal lesions showed that they were actually retinal detachments. Our patients and previously reported patients developed these lesions after scleral buckling and cryopexy. These lesions may represent persistent retinal detachment because of the presence of protein in the subretinal fluid.

Modest overexpression of neuropeptide Y in the brain leads to obesity after high-sucrose feeding

Neuropeptide Y (NPY), one of the most abundant peptide transmitters in the mammalian brain, is assumed to play an important role in feeding and body weight regulation. However, there is little genetic evidence that overexpression or knockout of the NPY gene leads to altered body weight regulation. Previously, we developed NPY-overexpressing mice by using the Thy-1 promoter, which restricts NPY expression strictly within neurons in the central nervous system, but we failed to observe the obese phenotype in the heterozygote. Here we report that in the homozygous mice, overexpression of NPY leads to an obese phenotype, but only after appropriate dietary exposure. NPY-overexpressing mice exhibited significantly increased body weight gain with transiently increased food intake after 50% sucrose--loaded diet, and later they developed hyperglycemia and hyperinsulinemia without altered glucose excursion during 1 year of our observation period.

Emerging functions of neuropeptide Y Y(2) receptors in the brain

The Y(2) receptor is the predominant neuropeptide Y (NPY) receptor subtype in the brain. Y(2) receptor mRNA is discretely distributed in the brain, including specific subregions of the hippocampus and the hypothalamus, and is largely consistent with the distribution of Y(2) receptor protein demonstrated by radioligand-binding methods. Y(2) receptor-mediated effects have been reported principally based on the observations using the C-terminal fragments of NPY. Recent studies indicate an involvement of the receptor in food intake, gastrointestinal motility, cardiovascular regulation, and neuronal excitability. Very recently, Y(2) receptor selective antagonist has been developed and Y(2) receptor-deficient animals have been created. These new pharmacological tools will help to clarify the roles of this receptor in brain functions.

[Abnormality in feeding and body weight regulation in obesity]

Obesity is, with rare exceptions, a complex phenotype resulting from interactions between environmental and genetic risk factor. Obesity is associated with diabetes, hypertension, and hyperlipidemia, leading to arteriosclerosis. Dysregulation of food intake and energy expenditure, and thus energy homeostasis, is now recognized as playing a major role in development of obesity. A detailed understanding of the physiology and genetics of the regulatory systems is critical for the development of new approaches for treating obesity and its sequelae.

Ghrelin is an appetite-stimulatory signal from stomach with structural resemblance to motilin

BACKGROUND & AIMS

: Ghrelin, an endogenous ligand for growth hormone secretagogue receptor, was recently identified in the rat stomach. We examined the effects of the gastric peptide ghrelin on energy balance in association with leptin and vagal nerve activity.

METHODS

: Food intake, oxygen consumption, gastric emptying, and hypothalamic neuropeptide Y (NPY) messenger RNA expression were measured after intra-third cerebroventricular or intraperitoneal injections of ghrelin in mice. The gastric vagal nerve activity was recorded after intravenous administration in rats. Gastric ghrelin gene expression was assessed by Northern blot analysis. Repeated coadministration of ghrelin and interleukin (IL)-1 beta was continued for 5 days.

RESULTS

: Ghrelin exhibited gastroprokinetic activity with structural resemblance to motilin and potent orexigenic activity through action on the hypothalamic neuropeptide Y (NPY) and Y(1) receptor, which was lost after vagotomy. Ghrelin decreased gastric vagal afferent discharge in contrast to other anorexigenic peptides that increased the activity. Ghrelin gene expression in the stomach was increased by fasting and in ob/ob mice, and was decreased by administration of leptin and IL-1 beta. Peripherally administered ghrelin blocked IL-1 beta-induced anorexia and produced positive energy balance by promoting food intake and decreasing energy expenditure.

CONCLUSIONS

: Ghrelin, which is negatively regulated by leptin and IL-1 beta, is secreted by the stomach and increases arcuate NPY expression, which in turn acts through Y(1) receptors to increase food intake and decrease energy expenditure. Gastric peptide ghrelin may thus function as part of the orexigenic pathway downstream from leptin and is a potential therapeutic target not only for obesity but also for anorexia and cachexia.

Decreased food intake and body weight in pancreatic polypeptide-overexpressing mice

BACKGROUND & AIMS

Pancreatic polypeptide (PP) is a 36-amino acid hormone produced by F cells within the pancreatic islets and the exocrine pancreas. The definitive function of PP in mammalian physiology remains to be determined. This study examined the effects of chronic overexpression of PP through the development of PP transgenic mice.

METHODS

PP transgenic mice were created by using mouse PP complementary DNA under the control of the cytomegalovirus immediate early enhancer-chicken beta-actin hybrid promoter (pCAGGS expression vector).

RESULTS

A unique line of transgenic mice was created that overexpresses PP in the pancreatic islets with low levels of expression in other tissues including the brain. Plasma PP concentrations were more than 20 times higher than those of control littermates. However, PP overproduction led to postnatal lethality in half of the pups because of markedly decreased milk intake. The remaining PP transgenic mice gained less weight with specifically reduced food intake and fat mass compared with controls, a result that was more evident in male than in female mice. The transgenic mice exhibited a reduced rate of gastric emptying of a solid meal but had normal oxygen consumption and fasting leptin levels. Immunoneutralization with anti-PP antiserum reversed the phenotypic changes of transgenic animals.

CONCLUSIONS

PP could be involved in feeding and body weight regulation partly through regulation of gastric emptying.

Cloning and sequencing of beta-mannosidase gene from Aspergillus aculeatus no. F-50

The manB gene, coding for a unique beta-mannosidase (MANB) of Aspergillus aculeatus, was cloned from genomic and cDNA libraries, and sequenced. The gene consists of 2,811 bp encoding a polypeptide of 937 amino acid residues with a molecular mass of 104,214 Da. The A. aculeatus MANB shared amino acid sequence identity with MANB of human (24%), goat (24%), bovine (24%), and Caenorhabditis elegans (22%). When the A. aculeatus MANB was compared with other related enzymes, a Glu residue corresponding to the active site identified by the Escherichia coli beta-galactosidase and the human beta-guclonidase was conserved. This is the first fungal gene that encodes MANB.

[The outline of in-home medical care in Japan]

In-home medical care is an issue which has come to the forefront recently, but it is as yet an undeveloped and unorganized field in Japan. However, in-home medical care is an extremely vital aspect in community medical care and the needs of the population in this field are expected to gradually expand. The human resources which will be responsible for carrying out in-home medical care is the focus of this study. Recently, the young physicians who have begun their practice as family physicians are capable of using IVH and other medical techniques. They are self-assertive in visiting their patients at home and a revolution in medical care awareness has begun to evolve. Old people's home visit nursing stations are certain to increase and the range of nursing duties which can be carried out in the home will become an issue. In addition, the role of home helpers is essential, although they are not medical personnel. The focus of in-home medical care services which will be placed under the supervision of a physician, will be the patient; and it is important that nurses, certified care workers, home helpers, etc. cooperate mutually in the care of the patient. Implementing in-home medical care as efficiently as possible will enable medical care to meet the needs of the population. In the 21 st century "in-home medical care" is anticipated to function and inseparably with hospital medical care and fully it is expected to become a fixed institution among the Japanese people.

Giant air cell of the petrous apex: a possible cause of facial hypalgesia

A giant air cell of the left petrous apex was found in a 23-year-old man with ipsilateral facial hypalgesia. The size of the giant air cell depicted on computed tomography was 1.5 x 2.0 x 2.0 cm. A coronal T1-weighted magnetic resonance image showed that the trigeminal nerve was compressed superomedially by a large signal void area that was probably a result of excessive pneumatization of the petrous apex. It is suggested that the facial hypalgesia was caused by the compression by the giant air cell of the petrous apex on the trigeminal nerve.