Simulation as a set-up for technical proficiency: can a virtual warm-up improve live fibre-optic intubation?

BACKGROUND

Fibre-optic intubation (FOI) is an advanced technical skill, which anaesthesia residents must frequently perform under pressure. In surgical subspecialties, a virtual 'warm-up' has been used to prime a practitioner's skill set immediately before performance of challenging procedures. This study examined whether a virtual warm-up improved the performance of elective live patient FOI by anaesthesia residents.

METHODS

Clinical anaesthesia yr 1 and 2 (CA1 and CA2) residents were recruited to perform elective asleep oral FOI. Residents either underwent a 5 min, guided warm-up (using a bronchoscopy simulator) immediately before live FOI on patients with predicted normal airways or performed live FOI on similar patients without the warm-up. Subjects were timed performing FOI (from scope passing teeth to viewing the carina) and were graded on a 45-point skill scale by attending anaesthetists. After a washout period, all subjects were resampled as members of the opposite cohort. Multivariate analysis was performed to control for variations in previous FOI experience of the residents.

RESULTS

Thirty-three anaesthesia residents were recruited, of whom 22 were CA1 and 11 were CA2. Virtual warm-up conferred a 37% reduction in time for CA1s (mean 35.8 (SD 3.2) s vs. 57 (SD 3.2) s, P<0.0002) and a 26% decrease for CA2s (mean 23 (SD 1.7) s vs. 31 (SD 1.7) s, P=0.0118). Global skill score increased with warm-up by 4.8 points for CA1s (mean 32.8 (SD 1.2) vs. 37.6 (SD 1.2), P=0.0079) and 5.1 points for CA2s (37.7 (SD 1.1) vs. 42.8 (SD 1.1), P=0.0125). Crossover period and sequence did not show a statistically significant association with performance.

CONCLUSIONS

Virtual warm-up significantly improved performance by residents of FOI in live patients with normal airway anatomy, as measured both by speed and by a scaled evaluation of skills.

Abstract P5-01-13: The Clinical Role and Cost Effectiveness of Breast-Specific Gamma Imaging (BSGI) in the Management of Patients with Negative or Indeterminate Mammographic and Sonographic Findings and an Unresolved Diagnostic Concern

Background: BSGI is a molecular imaging technique increasingly used to aid in the management of patients with negative or indeterminate mammograms and an unresolved clinical concern such as indeterminate densities, new vague calcifications, bloody nipple discharge, focal breast pain or palpable masses; especially in those of elevated risk and patients with dense breast tissue.

Purpose: This study examines the role and cost effectiveness of BSGI in providing additional information when conventional imaging is indeterminate and greater confidence is required to improve diagnostic accuracy.

Methods: This is a retrospective analysis of patients in our practice for whom BSGI was recommended due to an unresolved clinical concern following negative (BI-RADS 1 or2), indeterminate (BI-RADS 0 or 3), or discordant findings on mammography (MMG) or ultrasound (US). For all modalities, the radiologist had the patient's history and imaging studies available to them at the time of interpretation. BSGI studies were classified as negative (BI-RADS 0-3) or positive (BI-RADS 4-5). Biopsy or follow up imaging was performed as recommended by the radiologist. Pathology or 6 month follow up imaging was used as the gold standard and were classified as negative (benign pathology or no evidence of malignancy on follow up imaging) or positive (biopsy proven cancer).

Results: There were 95 patients with 102 regions of concern, yielding 15 biopsy proven malignant lesions and 87 benign findings on pathology or follow up imaging. BSGI was positive in 12 malignant and 33 benign lesions and negative in 54 benign lesions, yielding a sensitivity of 80% and a specificity of 62%. The negative predictive value of BSGI in this population was 95%.

Conclusion: BSGI contributed significantly to patient management by detecting cancer in 12 of the 95 patients (12.6%). The Medicare reimbursement rate for BSGI in our area is $203.26. Therefore the cost per cancer diagnosis in this population was approximately $1,608.35. If these patients had been sent for breast MRI, $1,026.38 Medicare locally, the cost per diagnosis would rise to $8,129.07. BSGI is a useful, cost effective, complimentary tool in the diagnostic work up of patients when a diagnostic concern remains after negative or indeterminate conventional imaging.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-01-13.

Repeated-batch production of kojic acid in a cell-retention fermenter using Aspergillus oryzae M3B9

A cell-retention fermenter was used for the pilot-scale production of kojic acid using an improved strain of Aspergillus oryzae in repeated-batch fermentations. Among the various carbon and nitrogen sources used, sucrose and yeast extract promoted pellet morphology of fungi and higher kojic acid production. Repeated-batch culture using a medium replacement ratio of 75% gave a productivity of 5.3 gL(-1)day(-1) after 11.5 days of cultivation. While batch culture in shake-flasks resulted in a productivity of 5.1 gL(-1)day(-1), a productivity of 5 gL(-1)day(-1) was obtained in a pilot-scale fermenter. By converting the batch culture into repeated batches, the non-productive downtime of cleaning, filling and sterilizing the fermenter between each batch were eliminated, thereby increasing the kojic acid productivity.

Soft-copy mammographic readings with different computer-assisted detection cuing environments: preliminary findings

PURPOSE

To assess the performance of radiologists in the detection of masses and microcalcification clusters on digitized mammograms by using different computer-assisted detection (CAD) cuing environments.

MATERIALS AND METHODS

Two hundred nine digitized mammograms depicting 57 verified masses and 38 microcalcification clusters in 85 positive and 35 negative cases were interpreted independently by seven radiologists using five display modes. Except for the first mode, for which no CAD results were provided, suspicious regions identified with a CAD scheme were cued in all the other modes by using a combination of two cuing sensitivities (90% and 50%) and two false-positive rates (0.5 and 2.0 per image). A receiver operating characteristic study was performed by using soft-copy images.

RESULTS

CAD cuing at 90% sensitivity and a rate of 0.5 false-positive region per image improved observer performance levels significantly (P < .01). As accuracy of CAD cuing decreased so did observer performances (P < .01). Cuing specificity affected mass detection more significantly, while cuing sensitivity affected detection of microcalcification clusters more significantly (P < .01). Reduction of cuing sensitivity and specificity significantly increased false-negative rates in noncued areas (P < .05). Trends were consistent for all observers.

CONCLUSION

CAD systems have the potential to significantly improve diagnostic performance in mammography. However, poorly performing schemes could adversely affect observer performance in both cued and noncued areas.

NQ-Y15 inhibits the calcium mobilization by elevation of cyclic AMP in rat platelets

2-1(4-Cyanophenyl)aminol-3-chloro-1,4-naphthalenedione (NQ-Y15) is a dual action drug which acts as a thromboxane A2 (TXA2) synthase inhibitor and TXA2/PGH2 receptor antagonist. In the present study, we examined the effects of NQ-Y15 on Ca2+ mobilization, which is the common event in various types of platelet activation, in arachidonic acid (AA)-stimulated rat platelets. The elevation of cytosolic Ca2+ concentration ([Ca2+]i) induced by AA was inhibited by NQ-Y15 in a concentration-dependent manner. This inhibition-effect of NQ-Y15 was found to be based on the suppression of the rise in [Ca2+]i by the inhibition of both Ca2+ release from internal stores and Ca2+ influx from the extracellular space. Our successive trial was focused on the role of cyclic AMP (cAMP) in the action of NQ-Y15, because cAMP was reported to be increased by dual action drugs such as picotamide and to inhibit the increase in [Ca2+]i. NQ-Y15 was confirmed to increase cAMP in AA-stimulated rat platelets. These results suggested that NQ-Y15 might inhibit the rise in [Ca2+]i in AA-treated rat platelets by increasing cAMP, which is involved in the inhibition of platelet activation.

Glutathione S-transferase mu modulates the stress-activated signals by suppressing apoptosis signal-regulating kinase 1

Apoptosis signal-regulating kinase 1 (ASK1) is a mitogen-activated protein kinase kinase kinase that can activate the c-Jun N-terminal kinase and the p38 signaling pathways. It plays a critical role in cytokine- and stress-induced apoptosis. To further characterize the mechanism of the regulation of the ASK1 signal, we searched for ASK1-interacting proteins employing the yeast two-hybrid method. The yeast two-hybrid assay indicated that mouse glutathione S-transferase Mu 1-1 (mGSTM1-1), an enzyme involved in the metabolism of drugs and xenobiotics, interacted with ASK1. We subsequently confirmed that mGSTM1-1 physically associated with ASK1 both in vivo and in vitro. The in vitro binding assay indicated that the C-terminal portion of mGSTM1-1 and the N-terminal region of ASK1 were crucial for binding one another. Furthermore, mGSTM1-1 suppressed stress-stimulated ASK1 activity in cultured cells. mGSTM1-1 also blocked ASK1 oligomerization. The ASK1 inhibition by mGSTM1-1 occurred independently of the glutathione-conjugating activity of mGSTM1-1. Moreover, mGSTM1-1 repressed ASK1-dependent apoptotic cell death. Taken together, our findings suggest that mGSTM1-1 functions as an endogenous inhibitor of ASK1. This highlights a novel function for mGSTM1-1 insofar as mGSTM1-1 may modulate stress-mediated signals by repressing ASK1, and this activity occurs independently of its well-known catalytic activity in intracellular glutathione metabolism.

Knowledge-based computer-aided detection of masses on digitized mammograms: a preliminary assessment

The purpose of this work was to develop and evaluate a computer-aided detection (CAD) scheme for the improvement of mass identification on digitized mammograms using a knowledge-based approach. Three hundred pathologically verified masses and 300 negative, but suspicious, regions, as initially identified by a rule-based CAD scheme, were randomly selected from a large clinical database for development purposes. In addition, 500 different positive and 500 negative regions were used to test the scheme. This suspicious region pruning scheme includes a learning process to establish a knowledge base that is then used to determine whether a previously identified suspicious region is likely to depict a true mass. This is accomplished by quantitatively characterizing the set of known masses, measuring "similarity" between a suspicious region and a "known" mass, then deriving a composite "likelihood" measure based on all "known" masses to determine the state of the suspicious region. To assess the performance of this method, receiver-operating characteristic (ROC) analyses were employed. Using a leave-one-out validation method with the development set of 600 regions, the knowledge-based CAD scheme achieved an area under the ROC curve of 0.83. Fifty-one percent of the previously identified false-positive regions were eliminated, while maintaining 90% sensitivity. During testing of the 1,000 independent regions, an area under the ROC curve as high as 0.80 was achieved. Knowledge-based approaches can yield a significant reduction in false-positive detections while maintaining reasonable sensitivity. This approach has the potential of improving the performance of other rule-based CAD schemes.

Vaginal fluid creatinine, human chorionic gonadotropin and alpha-fetoprotein levels for detecting premature rupture of membranes

BACKGROUND

Diagnosis of premature rupture of membranes (PROM) is difficult in equivocal cases. The concentrations of human chorionic gonadotropin (hCG), alpha-fetoprotein (AFP) and creatinine are high in amniotic fluid. The purpose of this study was to determine the usefulness of vaginal fluid hCG, AFP and creatinine measurements in the detection of PROM.

METHODS

About 3 ml of normal saline was used to irrigate the posterior vaginal fornix and was collected for the measurement of hCG, AFP and creatinine. The control group included 10 normal pregnant women in the third trimester (> 28 weeks of gestational age). Levels of hCG, AFP and creatinine were compared with those of 10 women with confirmed PROM.

RESULTS

The median levels of vaginal fluid hCG of normal pregnant women and pregnant women with confirmed PROM were 35.0 mIU/ml and 478.0 mIU/ml (p = 0.0046), respectively. For AFP, the corresponding values were 0.80 ng/ml and 54.24 ng/ml (p < 0.0001), respectively, and for creatinine, the values were 0.05 mg/dl and 0.95 mg/dl (p < 0.0001), respectively. All three markers were significantly higher in the experimental group than in the control group. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy for hCG were 80%, 70%, 72.7%, 77.8% and 75%, respectively. For AFP, these values were 90%, 100%, 100%, 90.9%, and 95.0%, respectively, and for creatinine, they were 90%, 100%, 100%, 90.9%, and 95%, respectively. The diagnostic value of AFP or creatinine level in vaginal washing may be better than that of hCG, though the difference was not statistically significant, probably due to the limited case number.

CONCLUSIONS

Creatinine in vaginal fluid washings is a useful marker for PROM. It was less expensive and easier to measure than hCG and AFP, and appears to be more accurate than hCG.

Improvement in macular function after retinal translocation surgery in a patient with age-related macular degeneration

PURPOSE

To assess focal electroretinographic findings before and after retinal translocation surgery in a patient with age-related macular degeneration.

METHOD

Case report. A 79-year-old man with a well-defined subfoveal choroidal neovascular membrane from age-related macular degeneration underwent preoperative and postoperative focal electroretinography.

RESULTS

After retinal translocation surgery, best-corrected Snellen visual acuity improved from 9/200 to 20/60. A significant increase in mean foveal amplitude, from 0.08 microV to 0.16 microV (P = 0.008) was recorded.

CONCLUSION

Age-related macular degenerative changes in visual acuity and foveal electroretinogram amplitude may be reversible after retinal translocation surgery.

Use of preoperative MR imaging in the management of endometrial carcinoma: cost analysis

PURPOSE

To compare the cost of magnetic resonance (MR) imaging and its ability to direct the use of lymph node dissection with the cost and ability of conventional surgery for the staging of endometrial carcinoma.

MATERIALS AND METHODS

Preoperative MR images of 25 patients who underwent hysterectomy for endometrial carcinoma were retrospectively evaluated. MR imaging results were compared with those of intraoperative gross dissection of the uterus and final histopathologic examination. Medicare reimbursements for two scenarios were compared in each patient. In the MR imaging scenario, the necessity for lymph node dissection was based on MR imaging results and histologic findings at biopsy. In the actual scenario, lymph node dissection was performed at the surgeon's discretion on the basis of findings at gross dissection of the uterus and histologic examination at biopsy.

RESULTS

The cost of the MR imaging scenario, as defined by Medicare reimbursements, was 1% ($1, 265/$148,500) less than that of the actual scenario. In the MR imaging scenario, all patients who required lymph node dissection received it, and 86% of the lymph node dissections performed were necessary. In the actual scenario, one necessary lymph node dissection was not performed, and only 31% of the lymph node dissections performed were necessary.

CONCLUSION

Staging with MR imaging has costs and accuracy similar to those of the current method of staging with intraoperative gross dissection of the uterus. In addition, MR imaging decreases the number of unnecessary lymph node dissections.

Effects of brazilin on GLUT4 recruitment in isolated rat epididymal adipocytes

The effects of brazilin on glucose transport into isolated rat epididymal adipocytes were investigated. Brazilin increased [3H]2-deoxy-D-glucose uptake, which was characterized by an increase in Vmax with no effect on the Km value. Phenylarsine oxide, which inhibits the translocation of glucose transporters, decreased brazilin-stimulated glucose transport to the basal level. The inhibition of phosphatidylinositol 3-kinase (PI3-kinase) with wortmannin also blocked brazilin-stimulated glucose transport. Western blot analysis with an anti-GLUT4 antibody revealed that brazilin increased the translocation of GLUT4 from intracellular pools to the plasma membrane. Brazilin, in combination with phorbol ester, showed an additive effect on glucose transport. The stimulating effect of phorbol ester on glucose transport was inhibited by staurosporine, but the effect of brazilin remained unchanged. Protein kinase C activity was not influenced by brazilin treatment. The inhibition of protein synthesis showed no effect on brazilin-stimulated glucose transport, and GLUT4 content in the total membrane fraction was not altered as a result of treatment with brazilin for 4 hr. Metabolic labeling of GLUT4 with [35S]methionine showed that de novo synthesis of GLUT4 was not induced by brazilin. These data suggest that brazilin may increase glucose transport by recruitment of GLUT4 from intracellular pools to the plasma membrane of adipocytes via the activation of PI3-kinase. However, the effect of brazilin may not be mediated by GLUT4 synthesis and protein kinase C activation.

Validity of the visual function index (VF-14) in patients with retinal disease

OBJECTIVE

To test the validity of the Visual Function Index (VF-14) in patients with retinal disease.

DESIGN

A self-administered questionnaire package in association with clinical examination findings.

PARTICIPANTS

Consecutive patients attending the Vancouver General Hospital Eye Care Centre, Vancouver, British Columbia, retina clinic between May 1 and August 15, 1998.

MAIN OUTCOME MEASURES

Responses to the questionnaire package as they relate to global self-assessment scales and visual acuity. In addition, correlations were calculated between the VF-14, the 36-Item Short-Form Health Survey, a Weighted Comorbidity Scale, and visual acuity scores.

RESULT

Five hundred forty-seven patients were given the questionnaire package to complete. The VF-14 demonstrated a moderately strong positive association with patient self-rating of amount of trouble, satisfaction, and overall quality of vision. Correlations between the 36-Item Short-Form Health Survey, visual acuity, and the global scales were mild to moderate. The VF-14 was moderately correlated with visual acuity in the better and the worse eyes.

CONCLUSIONS

This study provides support for the validity of the VF-14 as a measure of functional impairment in patients with retinal disease. Once responsiveness has been measured and an analysis of disease subtypes has been carried out, the VF-14 will be ready for inclusion in clinical trials to evaluate patients' functional ability. Further implementation and development of this outcome measure will better our understanding of the utility of the functional assessment format for patients with retinal disease.

Prophylactic scleral buckle for prevention of retinal detachment following vitrectomy for macular hole

AIM

To review the rate of retinal detachment after macular hole surgery in patients who received vitrectomy and scleral buckle versus those who had vitrectomy alone.

METHODS

All patient charts and hospital records were examined for patients who underwent vitrectomy surgery for macular hole between September 1993 and June 1997. A total of 326 patients were identified and all were followed for a minimum of 6 months. Clinical records were examined for details of the surgical procedure, visual acuity, hole closure status, adjuvant therapies used, and postoperative retinal attachment status. Relative risks (the ratio of the incidence rate in the exposed to that in the unexposed) with 95% confidence intervals and chi(2) tests were calculated to determine which variables were associated with retinal detachment. The primary outcome measure in this review was retinal attachment status.

RESULTS

Of 326 eyes which underwent surgery for macular hole during the study period, scleral buckles were utilised in 152 (46.6%) patients. Analysis revealed a detachment rate of 13.2% in patients who did not receive a scleral buckle compared with 5.9% detachment rate in those who did. Analysis of these results indicated a 2.42 times greater risk of developing a retinal detachment in patients without a scleral buckle. Complications related to the use of scleral buckles occurred in two of 152 cases (1.3%)

CONCLUSIONS

A reduction in the rate of retinal detachment was noted in patients receiving prophylactic scleral buckles. Those finding suggest a possible beneficial effect of this adjunctive procedure in preventing postoperative retinal detachments. The authors are currently preparing a multicentred, prospective, clinical trial to further study this hypothesis

Age-related macular degeneration in Chinese-Canadians

BACKGROUND

Ethnicity has long been suspected to play a role in the risk of macular degeneration as well as its neovascular complications. We carried out a study to determine the prevalence of retinal diseases in Chinese-Canadians presenting for fluorescein angiography compared to a matched group of Canadians of European origin.

METHODS

We reviewed 20,000 consecutive fluorescein angiograms obtained between December 1987 and November 1993 at a tertiary referral centre for ophthalmic care in Vancouver. All patients identified by name as being of Chinese ancestry were identified and matched to a patient of European ancestry. The two groups were compared in regard to the prevalence of specific retinal diseases, including age-related macular degeneration (AMD).

RESULTS

Among the first 10,000 fluorescein angiograms, 417 patients of Chinese ancestry were identified, of whom 61 (14.6%) had the primary diagnosis of AMD. The rate among the patients of European ancestry was 30.4% (127/417) (odds ratio [OR] 2.12, 95% confidence interval [CI] 1.79 to 2.56) (p < 0.001). A total of 88 ethnic Chinese patients were identified among the subsequent 10,000 angiograms. Pigment epithelial detachments were more than twice as common in the overall group of ethnic Chinese patients as in their counterparts of European ancestry (OR 2.6, 95% CI 0.7 to 10.1). Choroidal neovascularization was 1.6 times more common in the latter group (95% CI 0.98 to 2.8).

INTERPRETATION

The findings support the growing clinical observations of a lower prevalence of AMD in nonwhite populations in addition to an increased prevalence of pigment epithelial detachments in ethnic Chinese patients.

In vitro fertilization is associated with an increased risk of hypospadias

PURPOSE

The purpose of this study was to determine if there is an increased incidence of hypospadias in male offspring conceived by in vitro fertilization (IVF).

MATERIALS AND METHODS

A retrospective institutional chart review from 1988 to 1992 and data from the Maryland Birth Defects Registry were statistically analyzed to assess the risk of hypospadias with IVF.

RESULTS

The data for the 5-year period indicated a 5-fold increased risk of hypospadias after IVF, with an incidence of approximately 1.5% in the IVF group and 0.3% in the control group. The only recognized difference between the groups was maternal progesterone administration in the IVF group but the cause of the increased risk of hypospadias was unknown. The distribution of hypospadias severity was similar in both groups.

CONCLUSIONS

Male newborns conceived by IVF have a 5-fold increased risk of hypospadias, which may be related to maternal progesterone administration, or other maternal or fetal endocrine abnormalities that may or may not be related to infertility. Health care providers should be aware of this risk so that they can properly counsel infertile couples seeking assisted reproduction by IVF technology.

Molecular cloning of multiple splicing variants of JIP-1 preferentially expressed in brain

Stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) is activated by a variety of cellular or environmental stresses. Proper regulation of the SAPK/JNK pathway may be critical for cell survival or death under various conditions. In this study, we report the molecular cloning of novel isoforms of JIP-1, which harbor a putative phosphotyrosine interaction domain and a helix-loop-helix domain, as well as an SH3 homologous region in the C terminus. Northern analysis indicates that transcription variant jip-1 is expressed in brain and kidney and transcription variants jip-2 and jip-3 are specifically expressed in brain. In situ hybridization data showed that the hybridized jip messages were heavily concentrated in adult brain, and were particularly enriched in the cerebral cortex and hippocampus, the brain regions vulnerable to pathological states such as hypoxia-ischemia, epilepsy, and Alzheimer's disease. All the deduced protein products of the jip transcription variants appear to have a similar property in that they inhibit the SAPK/JNK stimulation when overexpressed. Inhibition of SAPK activation by overexpression of the novel isoform JIP-2a resulted in suppression of etoposide-induced cell death in a neuroglioma cell line, N18TG. These findings suggest that JIP may play an important role in regulation of the SAPK pathway that is involved in stress-induced cellular responses.

Effects of Brazilin on the phospholipase A2 activity and changes of intracellular free calcium concentration in rat platelets

Brazilin (7,11b-dihydrobenz[b]indeno[1,2-d]pyran-3,6a,9,10 (6 H)-tetrol) inhibited thrombin-,collagen- and ADP-induced aggregation of washed rat platelets. Thrombin- and collagen-induced ATP release were also inhibited by brazilin in a concentration-dependent manner. Brazilin inhibited the formation of platelet thromboxane A2 caused by thrombin, whereas it had no effect on the prostaglandin D2 formation. Brazilin inhibited [3H]-arachidonic acid liberation from membrane phospholipids of thrombin-stimulated platelets. Brazilin inhibited the rise of intracellular free calcium caused by thrombin. These results indicate that the inhibition of phospholipase (PLA2) activity and [Ca2+]i elevation might be at least a part of antiplatelet mechanism of brazilin.

An acidic glutaryl-7-aminocephalosporanic acid acylase from Pseudomonas nitroreducens

A glutaryl-7-aminocephalosporanic acid (GL-7-ACA) acylase was purified 58-fold from Pseudomonas nitroreducens in a two-step procedure involving osmotic shock and carboxymethyl-Sepharose chromatography with a yield of 26%. The molecular mass of the native enzyme was 58 kDa. SDS/PAGE revealed that it consisted of two non-identical subunits with molecular masses of 35 and 21 kDa. The isoelectric point of the purified enzyme was 5.3. The enzyme had an optimal pH of 5.5 and an optimal temperature of 43 degrees C. The purified enzyme exhibited not only GL-7-ACA acylase activity but also gamma-glutamyltranspeptidase activity. The Km values of the enzyme for GL-7-ACA and L-gamma-glutamyl p-nitroanilide were 10.41 mM and 5.92 microM respectively.

A long-term follow-up of choroidal osteoma

OBJECTIVE

To provide long-term follow-up information on a large series of patients with choroidal osteoma.

METHODS

Review of patients with a diagnosis of choroidal osteoma who had been examined at the Bascom Palmer Eye Institute, Miami, Fla, or known to one of us (J.D.M.G.). Information was obtained from hospital medical records or by a questionnaire sent to referring ophthalmologists. Life-table analysis was used to study the loss of vision and development of choroidal neovascularization.

RESULTS

We followed up 36 patients, 31 (89%) were female, mean age, 21 years (range, 5-54 years) for a mean of 10 years (range, 2-22 years). Growth was observed for 9 (41%) of 22 well-documented osteomas. The probability of loss of visual acuity to 20/200 or worse was 58% by 10 years and 62% by 20 years. The probability of developing choroidal neovascularization was 47% by 10 years and 56% by 20 years. Successful treatment of the choroidal neovascularization with laser photocoagulation was performed for 5 (25%) of 20 patients.

CONCLUSIONS

Most patients with choroidal osteomas maintain good vision in at least 1 eye, but they have a high risk of developing choroidal neovascularization. When this occurs, only a minority can be successfully treated with laser photocoagulation.

Neuronal nitric oxide synthase in the canine prostate: aging, sex steroid, and pathology correlations

Nitric oxide synthase (NOS) is expressed in the prostate of various species, including humans. NOS catalyzes the production of nitric oxide (NO), which may function in prostatic smooth-muscle relaxation. To investigate further the role of NO in the prostate, we examined neuronal NOS expression in the aging canine prostate, after hormonal perturbation, and correlated these results with histopathologic findings. The study comprised the following treatment groups: intact dogs (treatment group 1, n = 6); dogs who were castrated at 7 days of age and received testosterone and estrogen replacement at 2 years of age (treatment group 2, n = 10); and dogs who were castrated at 2 years of age and received testosterone and estrogen replacement at 2 years of age (treatment group 3, n = 9). Studies were done on prostates removed from dogs after euthanasia at 6 years of age. In treatment group 1, complex benign prostatic hyperplasia (BPH) was observed in all specimens. In treatment group 2, atrophy was observed in 70%, normal prostate with small areas of hyperplasia in 20%, and BPH in 10% of specimens. In treatment group 3, atrophy was observed in 78%, normal histology with small areas of hyperplasia in 11%, and BPH in 11% of specimens. Neuronal NOS localizations were confirmed by western blot analysis and by immunohistochemistry in 0% and 17%, respectively, of specimens in treatment group 1, in 60% and 70%, respectively, of specimens in treatment group 2, and in 67% and 71%, respectively, of specimens in treatment group 3. Neuronal NOS immunoreactivity was localized in histologically normal prostates of four intact, young-adult control dogs (2 years of age). For all treatment groups, neuronal NOS immunoreactivity was confirmed by western blot in 86% of atrophic prostates but in no prostates with BPH (P < 0.001), and it was confirmed by immunohistochemistry in 75% of atrophic prostates but in only 13% of prostates with BPH (P < 0.02). These data suggest that, in the canine prostate, NO release relates to growth and pathology. Low levels of neuronal NOS expression in BPH tissue, compared with higher levels in atrophic tissue, suggest that neuronal NOS expression is down-regulated in the prostate with benign cellular proliferation whereas it is maintained or possibly up-regulated in the prostate with prostatic involution. Whether altered neuronal NOS expression contributes to the pathogeneses of BPH and prostatic involution or whether it occurs as a consequence of these processes requires further investigation.

Computed radiography versus screen-film mammography in detection of simulated microcalcifications: a receiver operating characteristic study based on phantom images

RATIONALE AND OBJECTIVES

The authors compare a 43-micron computed radiographic system with a mammographic screen-film system for detection of simulated microcalcifications in an observer-performance study.

MATERIALS AND METHODS

The task of detecting microcalcifications was simulated by imaging aluminum wire segments (200-500 microns in length; 100, 125, or 150 microns in diameter) that overlapped with tissue background structures produced by beef brisket. A total of 288 such simulations were generated and examined with both computed radiography and conventional screen-film mammography techniques. Computed radiography was performed with high-resolution plates, a 43-micron image reader, and a 43-micron laser film printer. Computed radiographic images were printed with simple contrast enhancement and compared with screen-film images in a receiver operating characteristic study in which experienced readers detected and scored the simulated microcalcifications. Observer performance was quantitated and compared by computing the area under the receiver operating characteristic curve.

RESULTS

Although the resolution of the computed radiography system was better than that of commercial systems, it fell short of that of screen-film systems. For the 100-micron microcalcifications, the difference in the average area under the curve was not statistically significant, but it was significant for the larger simulated microcalcifications: the average area under the curve was 0.58 for computed radiography versus 0.76 for screen-film imaging for the 125-micron microcalcifications and 0.83 versus 1.00, respectively, for the 150-micron microcalcifications.

CONCLUSION

Observer performance in the detection of small simulated microcalcifications (100-150 microns in diameter) is better with screen-film images than with high-resolution computed radiographic images.

Brazilin modulates immune function mainly by augmenting T cell activity in halothane administered mice

Previously we reported that brazilin, the main principle of Caesalpinia sappan, was able to improve the altered immune functions caused by halothane administration in mice. To elucidate the mechanisms of its immunomodulating activities, the effects of brazilin on the functions of T cells and splenic cellularity were investigated. Brazilin decreased splenic cellularity and IL-2 production which had been augmented in mice treated with halothane (21.5% in olive oil, 10 mmol/kg) for 4 consecutive days whereas the reduced expression of IL-2 receptors by ConA or standard IL-2 was increased by brazilin treatment. These data indicate that halothane induced a dysfunction of T cells resulting in abnormal immune responses and these altered immune functions might be improved mainly by affecting the function of T cells.

Central cloudy corneal dystrophy of Francois. A clinicopathologic study

Central cloudy corneal dystrophy of Francois was first described in 1955 by J. Francois; its pathophysiology remains unknown. An 80-year-old woman with bilateral central cloudy corneal dystrophy of Francois was examined after having undergone a combined penetrating keratoplasty and cataract extraction. The corneal button was obtained. Light microscopy revealed stromal staining for acid mucopolysaccharide. Transmission electron microscopy revealed extracellular vacuoles, some of which had fibrillogranular material and electron-dense deposits. Fibrillogranular material was present in and around some keratocytes. Numerous endothelial vacuoles contained light-staining fibrillogranular material and round electron-dense granules. Our findings suggest that the opacities in patients with central cloudy corneal dystrophy of Francois are due to the extracellular accumulation of mucopolysaccharide and lipidlike material. Further studies are needed to elucidate the nature of these deposits.

Thromboxane A2 synthase inhibition and thromboxane A2 receptor blockade by 2-[(4-cyanophenyl)amino]-3-chloro-1,4-naphthalenedione (NQ-Y15) in rat platelets

The effects of 2-[(4-acetylphenyl)amino]-3-chloro-1,4-naphthalenedione (NQ-Y15), a synthetic 1,4-naphthoquinone derivative, on platelet activity and its mechanism of action were investigated. NQ-Y15 caused a concentration-dependent inhibition of the aggregation induced by thrombin, collagen, arachidonic acid (AA), and A23187. The IC50 values of NQ-Y15 on thrombin (0.1 U/mL)-, collagen (10 microg/mL)-, AA (50 microM)-, and A23187 (2 microM)-induced aggregation were 36.2 +/- 1.5, 6.7 +/- 0.7, 35.4 +/- 1.7, and 93.1 +/- 1.4 microM, respectively. NQ-Y15 also inhibited thrombin-, collagen-, AA-, and A23187-stimulated serotonin secretion in a concentration-dependent manner. However, a high concentration (100 microM) of NQ-Y15 showed no significant inhibitory effect on ADP-induced primary aggregation, which is independent of thromboxane A2 (TXA2) production in rat platelets. In fura-2-loaded platelets, the elevation of intracellular free calcium concentration stimulated by AA, thrombin, and 4-bromo-A23187 was inhibited by NQ-Y15 in a concentration-dependent manner. The formation of TXA2 caused by AA, thrombin, and collagen was inhibited significantly by NQ-Y15. NQ-Y15 inhibited TXA2 synthase in intact rat platelets, since this agent reduced the conversion of prostaglandin (PG) H2 to TXA2. Similarly, NQ-Y15 selectively inhibited the TXA2 synthase activity in human platelet microsomes, whereas it had no effect on activity of phospholipase A2, cyclooxygenase, and PGI2 synthase in vitro. NQ-Y15 inhibited platelet aggregation induced by the endoperoxide analogue U46619 in human platelets, indicating TXA2 receptor antagonism, possibly of a competitive nature. These results suggest that the antiplatelet effect of NQ-Y15 is due to a combination of TXA2 synthase inhibition with TXA2 receptor blockade, and that it may be useful as an antithrombotic agent.

Effects of calcium on brazilin-induced glucose transport in isolated rat epididymal adipocytes

Brazilin increased [3H]2-deoxyglucose uptake in isolated rat epididymal adipocytes. The fact that calcium may be required for the stimulatory effects of insulin on glucose transport suggests that brazilin might also require calcium for its glucose transport-stimulating action. Changes in the concentration of extracellular calcium had no significant effect on brazilin-induced glucose transport. Nifedipine and verapamil decreased brazilin-induced glucose transport, and quin2-AM abolished the effect of brazilin on glucose transport. A23187, however, showed no effect on brazilin action. 45Ca2+ uptake into adipocytes was not influenced by brazilin treatment, and trifluoperazine significantly inhibited the effect of brazilin on glucose transport. These data suggest that calmodulin and the maintenance of the intracellular calcium concentration, rather than an increase in it, may be essential for the stimulatory action of brazilin on glucose transport.

Treatment of capillary vascular malformation (port-wine stains) with photochemotherapy

One-hundred and thirty patients (85 female, 45 male) with port-wine stains were treated with photodynamic therapy, also called photochemotherapy, which recently has become acknowledged as effective for a variety of malignant tumors. Probably based on the photochemical reaction with the generation of toxic species, photochemotherapy results in endothelial cell injury and death of abnormal capillaries under overlying epidermis. A retrospective review of 118 available patients with port-wine stains reveals that 98.3 percent responded to photochemotherapy with varying degrees of success after one-time treatment. Results were reported under a simple classification system ranging from ordinary to dilated to posttreatment type. In the ordinary group, the results evaluated as excellent, good, fair, and poor were 37.8, 53.7, 8.5, and 0 percent, respectively, before a second treatment; the treated area was an average of 9.8 (range 7 to 13) cm in diameter. In addition, hypertrophic scars, permanent hyperpigmentation, and hypopigmentation were not seen based on proper parameters. Photochemotherapy offers a potentially efficient and promising choice based on a completely different mechanism from that of selected photothermal therapy with the pulsed-dye laser.

Preliminary clinical evaluation of a high-resolution telemammography system

RATIONALE AND OBJECTIVES

The authors designed, assembled, tested, and clinically evaluated a high-quality, fast, and relatively inexpensive telemammography system.

METHODS

The authors designed a telemammography system that uses a high-resolution film digitizer and high data compression (> or = 40:1) to send images over regular telephone lines to a high-resolution laser printer that produces images with the look and feel of the original image and can operate in a hub and spokes mode. The authors then evaluated the system's performance. In a preliminary clinical study, interpretations of the laser-printed system's output of 119 cases were compared with the original interpretations, followed by a review of any clinically significant differences.

RESULTS

With the exception of the laser printer, which is a modified off-the-shelf product, all hardware components of the system are commercially available products. The system digitizes (50 microns pixel size), compresses, transmits, receives, decompresses, and prints a 30 MB mammography file in less than 4 minutes. In the clinical study, there were 13 differences (in 13 cases) in the level of concern or recommendations. Seven were found to be clinically insignificant by a third-party review. The remaining six were reviewed by the original interpreter, and three were determined to be significant enough for further action. All were found to result from intra-reader variability rather than differences in visualization of possible abnormalities.

CONCLUSIONS

Almost real-time, high-quality telemammography without geographic boundaries is possible with the use of high-level data compression. Telemammography with laser-printed film as the display may make it possible to offer mammographic services in remote locations while using commercially available technology.

Nitric oxide modulates human chorionic gonadotropin-induced ovulation in the rabbit

OBJECTIVE

To examine the potential role of the L-arginine:nitric oxide pathway in hCG-induced ovulation in the rabbit.

DESIGN

Randomized, controlled animal study.

SETTING

University research laboratory.

INTERVENTION(S)

Nitric oxide synthase, the enzyme that produces nitric oxide (NO), was immunohistochemically localized in the ovary. NG-nitro-L-arginine methyl ester (L-NAME), an analogue of L-arginine, which inhibits the enzyme NO synthase, and the inactive D-enantiomer were administered in vivo and/or in vitro via an isolated, perfused ovary preparation during the periovulatory period.

MAIN OUTCOME MEASURE(S)

Rate of follicular rupture (ovulatory efficiency).

RESULT(S)

Immunohistochemical staining for NO synthase was localized specifically to the granulosa cell layer of the follicle and the endothelium and adventitia of ovarian blood vessels. In vivo administration of L-NAME significantly reduced the percentage of large follicles that ovulated in response to hCG (treated 24.6%, control 68.1%). Similarly, exposure of the in vitro-perfused ovary to L-NAME significantly reduced follicular rupture (treated 32.8%, control 64.2%). In contrast, addition of an equimolar concentration of D-NAME to the perfusion medium had no significant effect on the rate of ovulation (treated 83.3%, control 61.3%).

CONCLUSION(S)

The stereospecific inhibition of follicular rupture by the arginine analogue suggests that NO production by the ovary is an important feature of the normal physiologic processes of the periovulatory period.

Partial sympathetic denervation of the rat epididymis permits fertilization but inhibits embryo development

The rat cauda epididymidis receives sympathetic innervation from the inferior mesenteric ganglion (IMG). We have previously demonstrated that surgical removal of the IMG and proximal hypogastric nerves (IMG denervation) results in significant and cauda-specific changes in epididymal sperm transport, sperm motility, luminal fluid protein composition, and tissue histology. In the present study we used natural mating trials and intrauterine insemination (IUI) techniques to determine whether or not IMG denervation affects male fertility and reproductive capacity. For the initial studies, adult male Sprague Dawley rats were mated with estrous females 1 and 4 weeks following IMG denervation. Nine days after mating, uterine implantation sites and corpora lutea (CL) were counted. In females mated with sham-operated control males, 85.8% of ovulated oocytes were fertilized and subsequently implanted. In contrast, females mated with IMG-denervated males 1 or 4 weeks following surgery had 0% and 3.5%, respectively, of ovulated oocytes fertilized and implanted. For rats maintained 21 days after mating, an average of 13 +/- 1 pups were delivered by each of nine females mated with sham-operated control male rats; whereas, only seven morphologically normal pups were delivered by one of 14 females mated with IMG-denervated male rats. Additional experiments demonstrated that the decrement in offspring was, in part, due to a significant decrease in the number of spermatozoa in the female uterus following mating with IMG-denervated males. To determine whether IMG denervation exerted an additional effect directly on the fertilizing ability of spermatozoa, IUI experiments were performed. Six million cauda epididymal spermatozoa from 1- or 4-week IMG-denervated males were inseminated into the uterine horns of luteinzing hormone-releasing hormone (LHRH)-synchronized females and 9 days later implantation sites and CL were counted. Implantations were observed for 78%, 28%, and 25% of ovulated oocytes following IUI with spermatozoa from sham-operated controls and from 1- and 4-week IMG-denervated rats, respectively. To determine whether the reduction in implantation sites following IUI with spermatozoa from IMG-denervated rats resulted from impaired oocyte fertilization, studies were performed in which oocytes were retrieved and stained 24 hours after IUI. Comparable fertilization rates of 76.5% and 89.0% were observed using cauda epididymal spermatozoa from IMG-denervated and sham-operated control males, respectively, indicating that oocyte fertilization was not affected by the loss of innervation. These studies establish the importance of innervation from the IMG for ejaculatory competence and sperm reproductive capacity in the male rat. These data further suggest that sympathetic innervation in the epididymis critically influences paternal factors associated with embryonic development.

Comparison of single photon emission computed tomography findings in cases of healthy adults and solvent-exposed adults

Single photon emission computed tomography (SPECT) is a useful tool in measuring dynamic brain functioning. Its potential to reveal the physiological mechanisms of neurotoxicity has not been fully explored. In the present study, the SPECT findings for 25 healthy control subjects were compared to the findings for 25 mixed organic solvent exposure subjects. Specific physiological abnormalities related to regional cerebral blood flow activity (rCBF) were revealed. In the early phase of uptake, significantly decreased uptake was found in the mixed organic solvent group; in the late phase of uptake, a significant increase in uptake was found in specific regions of interest. The discovery of this abnormality in brain functioning may be a significant step toward the creation of a biological marker of neurotoxicity. Early detection of neurotoxicity is important in occupational medicine to prevent neurotoxic illnesses in working populations.

Neuronal input from the inferior mesenteric ganglion (IMG) affects sperm transport within the rat cauda epididymis

Sympathetic nerves emanating from the inferior mesenteric ganglion (IMG) innervate the mammalian epididymis and vas deferens. We have reported previously that surgical removal of the rat IMG results in excessive accumulation of spermatozoa within the cauda epididymis. The objective of the present study was to determine whether sperm accumulation following IMG removal was due to a denervation-induced change in the rate of sperm transport within the cauda epididymis. In these studies epididymal sperm numbers were counted and used as a measure of sperm transport within the epididymis. In order to examine sperm transport within the cauda epididymis specifically, efferent duct ligation (EDL) was used to prevent further entry of testicular spermatozoa into the epididymis. Rats were divided into four treatment groups: sham-operated control, EDL alone for 7 days (EDL + 7), EDL alone for 14 days (EDL + 14), or EDL for 7 days at which time the IMG was removed and the rats were maintained for an additional 7 days (EDL + IMG). Epididymides were homogenized and the number of spermatozoa in the caput and cauda epididymis was counted. In EDL + 7 rats, the caput epididymis was devoid of spermatozoa. The rate of transit of spermatozoa through the cauda epididymis of EDL + 7 rats was approximately 3.43 million/day. The total number of cauda epididymal spermatozoa in EDL + 7 rats was reduced by 20% compared to sham-operated control rats. In EDL + 14 rats, spermatozoa transited the cauda epididymis at a rate of approximately 9.57 million/day, and the total number of spermatozoa in the cauda epididymis was reduced by 73% compared to sham-operated controls. If the IMG was removed 7 days following EDL, spermatozoa transited the cauda epididymis at a rate comparable to that observed in EDL + 7 rats (3.39 million/day). Following IMG denervation of EDL + 7 rats, cauda epididymal sperm numbers were maintained at levels observed in the EDL + 7 rats. These data demonstrate that the transport of spermatozoa through the cauda epididymis is influenced significantly by neuronal input from the IMG.

The use of 5,6 benzo-[alpha]-pyrone (coumarin) and heating by microwaves in the treatment of chronic lymphedema of the legs

Sixty patients with leg lymphedema from a variety of etiologies were divided into randomized two groups, matched by Grade, duration, age, sex, and cause of lymphedema. Using a double-blind format, one group received 5,6 benzo-[alpha]-pyrone (coumarin 1,2 benzopyrone, 400 mg/day) for six months; the other received a placebo. For the next six months, both groups received a standardized regimen of heat (using microwaves) coupled with compression garments. Benzopyrone produced approximately 20% reduction in the volume (p = 10(-4)) and improvement in circumferences and tonometry (p = 10(-5) and 10(-7)). Symptoms (feelings of swelling, pain, heaviness and loss of mobility) were also significantly improved (p = 0.03 to 10(-7)). During the second six months, when microwave heat therapy was added to drug therapy, the patients who had previously received the placebo showed significant improvement (p = 0.03 to 10(-9)) in signs and symptoms of lymphedema. Some, but not all, of the group that was receiving benzopyrones were also significantly improved by heat therapy (p = 0.8 to 0.002). Taking benzopyrones for 12 months plus heat treatment for six months was significantly better, for some criteria, than the placebo plus heat therapy (p = 0.7 to 0.04). On the other hand, heat plus either placebo or benzopyrone was often significantly better than either the active or inactive drug without heat (p = 0.8 to 10(-9)).

Echographic findings in benign reactive lymphoid hyperplasia of the choroid

BACKGROUND

Benign reactive lymphoid hyperplasia is an uncommon uveal tumor. Misdiagnosis may lead to unnecessary enucleations. Clinical evaluation alone is usually not sufficient to diagnose this tumor.

OBJECTIVE

To evaluate the utility of standardized echography in the recognition of this disease.

METHODS

Retrospective review of the medical and echographic records of 6 patients with choroidal involvement of benign reactive lymphoid hyperplasia.

RESULTS

Extraocular episcleral lymphoid nodules were present in 5 of the 6 patients and were usually seen as a late manifestation of the disease. Two patients had repeated echography after treatment of the tumor and showed marked regression of the episcleral nodules.

CONCLUSIONS

A combination of clinical and echographic findings can assist in the accurate diagnosis of this rare uveal tumor. The presence of episcleral nodules on standardized echography supports the diagnosis.

Microwave heating in the management of postmastectomy upper limb lymphedema

The results of treating chronic lymphedema using microwave heating are described in 45 patients with postmastectomy lymphedema of the upper extremity. Forty-five patients showed a significant (p < 0.01) reduction in the amount of peripheral edema after two courses of treatment. The incidence and severity of secondary acute inflammation (erysipelas) were also sharply reduced (p < 0.01). The elasticity of the soft tissue was restored.

Conjunctival intraepithelial neoplasia. A possible marker for human immunodeficiency virus infection?

BACKGROUND

Conjunctival intraepithelial neoplasia has traditionally been found at the limbus in elderly individuals. Recently, this ocular tumor has been observed in younger patients.

OBJECTIVE

To investigate the potential association of human immunodeficiency virus infection with the emergence of this atypical presentation of conjunctival intraepithelial neoplasia.

DESIGN, SETTING, AND PARTICIPANTS

Records of patients at the Bascom Palmer Eye Institute (Miami, Fla) in whom conjunctival intraepithelial neoplasia was diagnosed between January 1, 1991, and December 31, 1993, were reviewed. Attempts were made to contact those patients younger than 50 years for clinical evaluation and human immunodeficiency virus serologic testing.

RESULTS

Conjunctival intraepithelial neoplasia was diagnosed in 73 patients during the study period. Of the nine patients younger than 50 years, six were available for serologic testing. Three (50%) of these individuals were found to be positive for human immunodeficiency virus.

CONCLUSION

Human immunodeficiency virus testing and counseling should be considered in patients younger than 50 years in whom conjunctival intraepithelial neoplasia is diagnosed.

Changes in luminal fluid protein composition in the rat cauda epididymidis following partial sympathetic denervation

Sympathetic denervation of the rat cauda epididymidis by surgical removal of the inferior mesenteric ganglion (IMG) results in an excessive accumulation of sperm in the cauda epididymidis as well as significant changes in cauda sperm motility and cauda epididymal gross histology. The objective of the present study was to determine if the cauda-specific changes in sperm storage, sperm motility, and epididymal histology following the loss of sympathetic innervation were accompanied by changes in the protein composition of epididymal fluid. One and 4 weeks after surgical IMG removal or sham operations, luminal fluid obtained from the caput and cauda epididymidis and cauda epididymal sperm-associated proteins were subjected to two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and silver-stained proteins were quantitated. One week after IMG removal, two cauda epididymal fluid (CEF) proteins (2 and 13) had increased 43% and 49%, respectively, whereas four CEF proteins (5, 8, 9, and 19) had decreased between 30% and 73% compared to controls. Four weeks after IMG removal, changes in CEF proteins observed 1 week following surgery were no longer present, but the staining intensities of three additional CEF proteins (11, 12, and 18) were reduced an average of 70% compared to control CEF proteins. By obstructing the cauda epididymidis, we confirmed that the changes in CEF protein composition observed following IMG removal were not the result of sperm accumulation but were due directly to the loss of innervation; the staining intensity of CEF protein 2 increased as a result of excessive sperm accumulation in the cauda epididymidis both in the presence and absence of innervation from the IMG. No significant changes in caput epididymal fluid proteins or cauda epididymal sperm-associated proteins were detected following IMG removal. These data show that the protein composition of rat CEF is significantly affected by the loss of sympathetic innervation and suggest that neuronal input may play an important role in the maintenance of epididymal function.

Subjective quality assessment of computed radiography hand images

To evaluate the sensitivity of a non-receiver-operating characteristic (ROC) study in assessing small differences of perceived image quality of hand images acquired by computed radiography (CR) and conventional screen-film systems, hand images were acquired on 12 patients with both conventional screen-film and CR. Each CR image was then processed with three different edge-enhancement algorithms. One conventional film and four CR images were then viewed side by side by five radiologists. Observers rated perceived image quality of each radiograph using a 10-category discrete scale. The study was repeated after 6 weeks using a different block randomization scheme. Despite the small sample size, significant differences (P < .05) in assigned image quality were detected among CR images acquired at low, medium, and high resolutions. Image processing routines did not fully compensate for differences in quality between conventional film and CR-acquired images. The quality rating of the reference conventional image was found to be dependent on the quality of images with which it was compared. Small, highly sensitive study designs can be used to identify radiologists' perceived differences in image quality. "Reference" or "gold standard" quality are important in such studies. Edge-enhancement schemes cannot fully compensate for perceived image quality degradations because of reduced image resolution.

Idiopathic retinal vasculitis, aneurysms, and neuro-retinitis. Retinal Vasculitis Study

PURPOSE

The authors describe the clinical feature of ten patients with a new syndrome characterized by the presence of retinal vasculitis, multiple macroaneurysms, neuro-retinitis, and peripheral capillary nonperfusion.

METHODS

The authors evaluated ten patients identified to have clinical features compatible with the syndrome of idiopathic retinal vasculitis, aneurysms and neuroretinits (IRVAN). Clinical examination findings, sequential funds photographs (when available), fluorescein angiograms, systemic investigations, response to therapy, and visual outcomes were reviewed.

RESULTS

Seven eyes of four patients sustained a marked decrease in visual acuity of 20/200 or worse. Visual loss was due to a combination of an exudative maculopathy and sequelae of retinal ischemia. Capillary nonperfusion was seen in all ten patients and was severe enough to warrant panretinal laser photocoagulation in six patients. Systemic investigations were uniformly noncontributory. Oral prednisone appears to have little beneficial effects on patients with this disorder.

CONCLUSIONS

Patients with IRVAN have characteristic retinal features that readily identify this syndrome. An increased awareness of this rare syndrome may help to identify sight-threatening complications at an earlier stage. The authors caution against extensive medical investigations.

Asymmetric canthaxanthin retinopathy

PURPOSE/METHODS

We studied a case of crystalline retinopathy occurring after prolonged use of oral canthaxanthin. The patient was followed up for 38 months during which time she sustained a branch retinal vein occlusion in her left eye.

RESULTS/CONCLUSIONS

An asymmetric appearance to the crystalline deposition was noted with increased sedimentation seen in the left eye. Vascular alterations after a branch retinal vein occlusion may lead to local stasis that may exacerbate the development of canthaxanthin retinopathy.

The effect of androgen on nitric oxide synthase in the male reproductive tract of the rat

OBJECTIVE

To determine if nitric oxide synthase activity within the male reproductive tract is regulated by androgen.

DESIGN

Nitric oxide synthase activity was measured in the reproductive organs of three groups of mature rats: unoperated controls, 1-week castrates, and 1-week castrates given T capsules at the time of surgery. The presence of nitric oxide synthase activity was confirmed by using the nitric oxide synthase-specific inhibitor N-nitro-L-arginine methyl ester (L-NAME).

RESULTS

After castration, nitric oxide synthase activity was significantly reduced by 88%, 73%, and 54% in the caput, corpus, and cauda epididymidis, respectively. In the penis, nitric oxide synthase activity decreased 45% and nitric oxide synthase protein decreased 57% after castration. In the seminal vesicle and lateral prostate, nitric oxide synthase activity increased significantly after castration from nondetectable levels in controls. Nitric oxide synthase activity in the coagulating gland and ventral and dorsal prostate did not change after castration. The changes in nitric oxide synthase activity in all organs after castration were prevented by T replacement. Additionally, the activity measured in every organ in all three treatment groups was > 90% inhibited by L-NAME.

CONCLUSION

These data demonstrate that androgen differentially affects nitric oxide synthase activity in the male reproductive tract. To the best of our knowledge this is the first time that nitric oxide synthase activity has been shown to be influenced by androgen in any tissue.

Analysis of 136 cases of reconstructed penis using various methods

Our experience in reconstructive surgery of the penis in 136 cases is reported. The postoperative complication rate was 13.24 percent. Five methods were used: the radial forearm free flap, the superficial inferior epigastric artery flap, the superficial circumflex iliac artery flap, the anterolateral thigh flap, and the combined cutaneous flap. The choice of the method had to be made depending on the patient's condition and prediction of the operative results. The penis not only should have a good appearance with normal size but also should have good sensation and function. The keys to success of this operation are considered to be correct preoperative planning, careful manipulation, and excellent anastomoses.

Selection of processing algorithms for digital image compression: a rank-order study

RATIONALE AND OBJECTIVES

We investigated non-receiver operating characteristic (non-ROC) methods for the selection of processing algorithms for digital image compression.

METHODS

We performed a multipoint, rank-order study with 20 posteroanterior chest images, each processed using four different algorithms. Seven radiologists reviewed these alongside the digitized noncompressed image. Observers were forced to rank order the similarity and/or difference of the processed images to the nonprocessed image in each case.

RESULTS

A two-way analysis of variance of the rankings was statistically significant (p = .025), indicating that one processing scheme yielded images that were clearly perceived as the most similar to the nonprocessed images. The selected processing scheme was not the one that yielded the lowest quantitative difference from the nonprocessed images as measured by root mean square error.

CONCLUSION

Non-ROC study designs that are highly sensitive to small differences among similar images can be used to select processing algorithms.