Outcomes and Complications of Limbal Stem Cell Allograft Transplantation: A Report by the American Academy of Ophthalmology

PURPOSE

To review the published literature on the safety and outcomes of keratolimbal allograft (KLAL) transplantation and living-related conjunctival limbal allograft (lr-CLAL) transplantation for bilateral severe/total limbal stem cell deficiency (LSCD).

METHODS

Literature searches were last conducted in the PubMed database in February 2023 and were limited to the English language. They yielded 523 citations; 76 were reviewed in full text, and 21 met the inclusion criteria. Two studies were rated level II, and the remaining 19 studies were rated level III. There were no level I studies.

RESULTS

After KLAL surgery, best-corrected visual acuity (BCVA) improved in 42% to 92% of eyes at final follow-up (range, 12-95 months). The BCVA was unchanged in 17% to 39% of eyes and decreased in 8% to 29% of eyes. Two of 14 studies that evaluated the results of KLAL reported a notable decline in visual acuity over time postoperatively. Survival of KLAL was variable, ranging from 21% to 90% at last follow-up (range, 12-95 months) and decreased over time. For patients undergoing lr-CLAL surgery, BCVA improved in 31% to 100% of eyes at final follow-up (range, 16-49 months). Of the 9 studies evaluating lr-CLAL, 4 reported BCVA unchanged in 30% to 39% of patients, and 3 reported a decline in BCVA in 8% to 10% of patients. The survival rate of lr-CLAL ranged from 50% to 100% at final follow-up (range, 16-49 months). The most common complications were postoperative elevation of intraocular pressure, persistent epithelial defects, and acute allograft immune rejections.

CONCLUSIONS

Given limited options for patients with bilateral LSCD, both KLAL and lr-CLAL are viable choices that may provide improvement of vision and ocular surface findings. The studies trend toward a lower rejection rate and graft failure with lr-CLAL. However, the level and duration of immunosuppression vary widely between the studies and may impact allograft rejections and long-term graft survival. Complications related to immunosuppression are minimal. Repeat surgery may be needed to maintain a viable ocular surface. Reasonable long-term success can be achieved with both KLAL and lr-CLAL with appropriate systemic immunosuppression.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Insights Into Eye Care Accessibility: Geospatial Distribution of Eye Care Providers and Socioeconomic Factors by ZIP Code

Purpose

In the United States, the ZIP Code has long been used to collect geospatial data revealing disparities in social determinants of health. This cross-sectional study examines the distribution of eye care access in association with local socioeconomic factors at a ZIP Code level.

Methods

Data from the 2020 Centers of Medicare and Medicaid Services and American Community Survey were used to examine locations of 47,949 providers (17,631 ophthalmologists and 30,318 optometrists) and corresponding local socioeconomic variables (education, employment, and income). Multivariable zero-inflated negative binomial regression was used to model eye care provider count per capita in each ZIP Code area with socioeconomic factors as independent covariates.

Results

For every 1% increase in percentage of population over 25 years with a bachelor's degree or higher, the expected number of providers increases by 4.4% (incidence rate ratio [IRR] = 1.044; 95% confidence interval [CI], 1.041-1.046; P < 0.001). For every 1% increase in percentage unemployment, the expected number of providers decreases by 2.7% (IRR = 0.973; 95% CI, 0.964-0.983; P < 0.001). However, for every $1000 increase in median household income, the expected number of providers decreases by 1.6% (IRR = 0.984; 95% CI, 0.983-0.986; P < 0.001).

Conclusions

Disparities in access exist in areas of lower employment and educational attainment, as both have positive correlations with eye care provider access. Conversely, areas of greater median household income have lower access to providers.

Translational Relevance

This research contributes to a greater field studying social determinants of health and may inform public health strategies on allocation of providers to improve equitable access to vision care.

Advanced Corneal Imaging in Keratoconus: A Report by the American Academy of Ophthalmology

PURPOSE

To review the published literature on the diagnostic capabilities of the newest generation of corneal imaging devices for the identification of keratoconus.

METHODS

Corneal imaging devices studied included tomographic platforms (Scheimpflug photography, OCT) and functional biomechanical devices (imaging an air impulse on the cornea). A literature search in the PubMed database for English language studies was last conducted in February 2023. The search yielded 469 citations, which were reviewed in abstract form. Of these, 147 were relevant to the assessment objectives and underwent full-text review. Forty-five articles met the criteria for inclusion and were assigned a level of evidence rating by the panel methodologist. Twenty-six articles were rated level II, and 19 articles were rated level III. There were no level I evidence studies of corneal imaging for the diagnosis of keratoconus found in the literature. To provide a common cross-study outcome measure, diagnostic sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were extracted. (A perfect diagnostic test that identifies all cases properly has an AUC of 1.0.) RESULTS: For the detection of keratoconus, sensitivities for all devices and parameters (e.g., anterior or posterior corneal curvature, corneal thickness) ranged from 65% to 100%. The majority of studies and parameters had sensitivities greater than 90%. The AUCs ranged from 0.82 to 1.00, with the majority greater than 0.90. Combined indices that integrated multiple parameters had an AUC in the mid-0.90 range. Keratoconus suspect detection performance was lower with AUCs ranging from 0.66 to 0.99, but most devices and parameters had sensitivities less than 90%.

CONCLUSIONS

Modern corneal imaging devices provide improved characterization of the cornea and are accurate in detecting keratoconus with high AUCs ranging from 0.82 to 1.00. The detection of keratoconus suspects is less accurate with AUCs ranging from 0.66 to 0.99. Parameters based on single anatomic locations had a wide range of AUCs. Studies with combined indices using more data and parameters consistently reported high AUCs.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Thermal Pulsation in the Management of Meibomian Gland Dysfunction and Dry Eye: A Report by the American Academy of Ophthalmology

PURPOSE

To review the literature to determine the efficacy and safety of thermal pulsation technologies in improving signs or symptoms of meibomian gland dysfunction (MGD) and dry eye compared with no therapy or with conventional warm compress therapy or eyelid hygiene.

METHODS

A literature search was conducted in the PubMed database in June 2022 and again in March 2023 to identify all studies in the English language on the use of thermal pulsation to treat MGD or dry eye. The search yielded 59 citations, and 11 articles met all of the inclusion criteria. The panel methodologist then assigned a level of evidence rating for each study; 8 studies were rated level I evidence and 3 studies were rated level II evidence.

RESULTS

All included studies evaluated a single 12-minute session using the LipiFlow automated thermal pulsation system (TearScience, Inc, or Johnson & Johnson). Improvements were detected in subjective and objective metrics of MGD or dry eye in patients within 1 to 12 months of thermal pulsation treatment compared with nontreatment. Most of the studies (9/11) reported greater efficacy with thermal pulsation than with standard warm compress therapy and eyelid hygiene. Four of these studies showed relevant industry conflicts of interest. Two of the 4 level I studies without direct industry participation concluded that thermal pulsation treatment was not significantly different from conventional hygiene or warm compress therapy control treatments (in symptoms in one of the studies and in objective findings in the second study). No serious adverse events were reported in any of the 11 studies.

CONCLUSIONS

According to the current literature, a single thermal pulsation session may improve subjective or objective parameters of MGD and dry eye safely. However, industry support and participation were present in 4 of the 8 level I studies. The durability beyond several months and cost efficacy remain uncertain. Because the inclusion parameters of this assessment captured only the LipiFlow system, the conclusions are limited to that product. High-quality independent studies are needed to assess the long-term benefits of this intervention.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Seven Common Allergen Groups Causing Eyelid Dermatitis: Education and Avoidance Strategies

Objective

Eyelid dermatitis is most commonly attributed to allergic response. This retrospective clinical study identifies common allergens with eyelid involvement and addresses a literary gap by providing a clear approach for effective management of periorbital allergic contact dermatitis (ACD) recurrence.

Methods

Charts of 215 patients diagnosed with periorbital dermatitis who were patch tested with Mayo Clinic Standard Series, Extended Standard Series, and personal products from 2013 to 2017 were examined. Positive reaction rates for patients with eyelid involvement were compared to those without. Findings were also compared to North American Contact Dermatitis Group (NACDG) 2013–2014 and Mayo Clinic Contact Dermatitis Group (MCCDG) 2011–2015 general patch test populations.

Results

The 215 patients showed more common allergy to shellac, benzalkonium chloride, acrylates, and surfactants than the NACDG and MCCDG study populations. Periorbital ACD allergen groups eliciting the highest positive reaction rates were, in descending order: metals, shellac, preservatives, topical antibiotics, fragrances, acrylates, and surfactants. Of the corticosteroids, only tixocortol pivalate (the screening agent for prednisolone and fluorometholone) and budesonide elicited positive reactions.

Conclusion

The top seven eyelid ACD allergen groups were identified. Avoidance of these allergens can be straightforward, with initial empiric counseling and free, online allergen avoidance programs. Patients who are unresponsive to avoidance should undergo patch testing.

Nuclear Medicine and Molecular Imaging in Nodal Staging and Surveillance of Ocular Melanoma: Case Reports and Review of the Literature

Ocular melanoma (OM) is a rare noncutaneous malignancy and consists of 2 different subtypes based on the anatomic location in the eye: uveal melanoma and conjunctival melanoma. Like cutaneous melanoma, OM benefits from nuclear medicine and molecular imaging in nodal staging and clinical management. Through the illustration of 2 distinctive cases, we aim to demonstrate the complementary roles of standard lymphoscintigraphy, advanced SPECT/CT, ¹⁸F-FDG PET/CT, and ¹⁸F-FDG PET/MRI in accurate nodal staging and surveillance of OM. We also review the epidemiology, existing staging guidelines, and management of uveal melanoma and conjunctival melanoma.

Effects of Intense Pulsed Light on Tear Film TGF-β and Microbiome in Ocular Rosacea with Dry Eye

Purpose

To assess tear film transforming growth factor-beta (TGF-β) and ocular microbiome changes after intense pulsed light with meibomian gland expression (IPL-MGX) vs only MGX in treating ocular rosacea with dry eye symptoms.

Methods

Twenty patients were randomly assigned to IPL-MGX or MGX. Patients were examined, treated, and administered the ocular surface disease index (OSDI) survey every 4-6 weeks for four total treatments. Tear film and conjunctival samples were collected at first and last visits, and analyzed for TGF-β concentration and 16s rRNA amplicon sequencing of ocular microbiome. Wilcoxon Rank Sum and Sign-Rank were used to examine changes from baseline.

Results

OSDI revealed significantly greater improvement in symptoms after IPL-MGX (p=0.030) compared to MGX. There was no significant difference in mean TGF-β1, 2, or 3 concentration after IPL-MGX (p=0.385, 0.709, 0.948, respectively). Quantities of Clostridium, Klebsiella, Brevibacterium, Lactobacillus, Neisseria, Streptococcus, Corynebacterium, Butyricicoccus, and Actinomyces were significantly reduced from baseline in both groups but without a significant difference between the two treatment groups.

Conclusion

IPL-MGX improved dry eye symptoms more than MGX alone. IPL treatment offered no additional benefit to MGX in decreasing virulent bacteria present on the ocular surface and did not influence TGF-β levels in tears. Prospective studies on IPL-MGX with larger sample sizes are needed to further investigate cytokines and IPL in patients suffering from ocular rosacea with dry eye symptoms.

ClinicalTrialsgov Identifier

NCT03194698.

[Recurrence and influencing factors of diabetic foot ulcer in patients with type 2 diabetes mellitus]

Objective: To investigate the recurrence and influencing factors of diabetic foot ulcer in patients with type 2 diabetes mellitus. Methods: Totally 185 type 2 diabetes patients with new-onset of diabetic foot ulcers admitted to Fuyang People's Hospital of Anhui Province from January 2011 to December 2015 were enrolled in this study, including 120 males and 65 females, aged 40-79 years. All the patients were followed up for 3 years, and their clinical data were retrospectively analyzed by the case-control study. The Kaplan-Meier cumulative recurrence curve was drawn according to the 3-year cumulative recurrence rate of diabetic foot ulcers. The time to visit, toe involvement, and amputation of involved toes in patients with recurrent diabetic foot ulcer were counted at the initial onset and the recurrence of the ulcers, respectively, and the data were statistically analyzed with t test and chi-square test. According to the recurrence of diabetic foot ulcers, the patients were divided into foot ulcer recurrence group and foot ulcer non-recurrence group. The gender, age, course of diabetes mellitus, length of hospital stay, visit time, body mass index, glycosylated hemoglobin HbA1c, total bilirubin, albumin, creatinine, cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL), triglycerides, hemoglobin, white blood cell count, toe involvement, toe amputation, ankle-brachial index, diabetic retinopathy (DR), diabetic peripheral neuropathy (DPN), diabetic nephropathy (DN), history of hypertension, cardio-cerebrovascular disease, smoking, residence, solitary life, and walking disorder of patients between the two groups were compared, and the data were statistically analyzed with t test and chi-square test. Log-rank test was performed on the indexes with P<0.1 in comparison between two groups, and the indexes with statistically significant differences in Log-rank test were analyzed by multivariate Cox regression analysis to screen the influencing factors of recurrence of diabetic foot ulcer. Results: (1) The 3-year cumulative recurrence rate of diabetic foot ulcers in 185 patients with type 2 diabetes mellitus was 47.0% (87/185). (2) For 87 patients with diabetic foot ulcer recurrence, compared with that at the initial onset of the ulcers, the visit time was significantly shorter (t=10.593, P<0.01), the toe amputation rate was significantly increased (χ(2)=5.118, P<0.05), but there was no obvious change in toe involvement at the recurrence of the ulcers. (3) There were statistically significant differences in age, course of diabetes mellitus, length of hospital stay, body mass index, glycosylated hemoglobin HbA1c, total bilirubin, albumin, creatinine, cholesterol, LDL, HDL, hemoglobin, white blood cell count, gender, toe amputation, ankle-brachial index, DR, history of cardio-cerebrovascular disease, solitary life, and walking disorder of patients between foot ulcer recurrence group (87 patients) and foot ulcer non-recurrence group (98 patients) (t=5.123, 4.242, 5.324, -24.572, 6.102, -1.984, -9.747, 3.226, 3.076, 3.646, -4.683, -7.502, 8.095, χ(2)=5.621, 18.433, 4.546, 5.785, 9.655, 7.625, 7.886, P<0.05 or P<0.01), while the rest of the indexes of patients between the two groups were similar. Log-rank test showed that the two groups had statistically significant differences in age, course of diabetes mellitus, length of hospital stay, glycosylated hemoglobin HbA1c, total bilirubin, albumin, creatinine, ankle-brachial index, DPN, and walking disorder (χ(2)=210.046, 44.837, 34.107, 98.685, 66.532, 294.451, 260.554, 5.012, 6.818, 11.160, P<0.05 or P<0.01). Age, total bilirubin, albumin, DPN, and walking disorder were the influencing factors for the recurrence of diabetic foot ulcers in patients with type 2 diabetes mellitus (hazard ratio=1.024, 0.678, 0.849, 2.335, 4.099, 95% confidence interval=1.001-1.047, 0.558-0.823, 0.797-0.904, 1.280-4.258, 2.044-8.223, P<0.05 or P<0.01). Conclusions: The 3-year cumulative recurrence rate of diabetic foot ulcers in patients with type 2 diabetes mellitus is relatively high, with the influencing factors being age, total bilirubin, albumin, DPN, and walking disorder.

Climatic and Environmental Correlates of Dry Eye Disease Severity: A Report From the Dry Eye Assessment and Management (DREAM) Study

Purpose

Correlate climate, weather parameters, and environmental exposures with the severity of symptoms and signs of dry eye disease (DED) in Dry Eye Assessment and Management (DREAM) study participants.

Methods

Participants from five distinct climates completed the Ocular Surface Disease Index (OSDI) and were examined for corneal and conjunctival staining, tear breakup time (TBUT), and Schirmer's testing at baseline, 3, 6, and 12 months. Climate, weather parameters, and pollutants including ozone (O₃), carbon monoxide (CO), nitrous oxides (NO₂, NO_x, NO_y), sulfur dioxide (SO₂), particulate matter, and optical depth were obtained from governmental databases. Multivariate analysis and partial correlation coefficients (ρ) were used to assess associations, adjusted for age, sex, and the presence of Sjögren disease.

Results

Among 535 participants, 81% were female and mean age was 58 years. Participants from the Mediterranean climate demonstrated better corneal fluorescein staining, better TBUT, and higher Schirmer's test scores throughout the calendar year (each P < 0.0001). Greater corneal fluorescein staining was associated with lower humidity (P < 0.0038). TBUT measurements positively correlated with temperature, humidity, and dewpoint and inversely correlated with NO₂ levels (P < 0.0038). Paradoxically, some airborne pollutants were associated with less severe signs of dry eye (P < 0.0038). Windspeed was not correlated with signs of DED, and OSDI scores did not correlate with individual environmental exposures.

Conclusions

Dry eye signs differed between climates and local humidity levels. With the exception of NO₂, airborne pollutants were not associated with detrimental dry eye features.

Translational Relevance

These results support limiting dry air exposure for patients with DED.

Climatic and Environmental Correlates of Dry Eye Disease Severity: A Report From the Dry Eye Assessment and Management (DREAM) Study

PURPOSE

Correlate climate, weather parameters, and environmental exposures with the severity of symptoms and signs of dry eye disease (DED) in Dry Eye Assessment and Management (DREAM) study participants.

METHODS

Participants from five distinct climates completed the Ocular Surface Disease Index (OSDI) and were examined for corneal and conjunctival staining, tear breakup time (TBUT), and Schirmer's testing at baseline, 3, 6, and 12 months. Climate, weather parameters, and pollutants including ozone (O₃), carbon monoxide (CO), nitrous oxides (NO₂, NO_x, NO_y), sulfur dioxide (SO₂), particulate matter, and optical depth were obtained from governmental databases. Multivariate analysis and partial correlation coefficients (ρ) were used to assess associations, adjusted for age, sex, and the presence of Sjögren disease.

RESULTS

Among 535 participants, 81% were female and mean age was 58 years. Participants from the Mediterranean climate demonstrated better corneal fluorescein staining, better TBUT, and higher Schirmer's test scores throughout the calendar year (each P < 0.0001). Greater corneal fluorescein staining was associated with lower humidity (P < 0.0038). TBUT measurements positively correlated with temperature, humidity, and dewpoint and inversely correlated with NO₂ levels (P < 0.0038). Paradoxically, some airborne pollutants were associated with less severe signs of dry eye (P < 0.0038). Windspeed was not correlated with signs of DED, and OSDI scores did not correlate with individual environmental exposures.

CONCLUSIONS

Dry eye signs differed between climates and local humidity levels. With the exception of NO₂, airborne pollutants were not associated with detrimental dry eye features.

TRANSLATIONAL RELEVANCE

These results support limiting dry air exposure for patients with DED.

[Expression and distribution of programmed death receptor 1 and T cell immunoglobulin mucin 3 in breast cancer microenvironment and its relationship with clinicopathological features]

Objective: To explore the expression and distribution of programmed death receptor 1 (PD-1) and T-cell immunoglobulin mucin 3 (TIM-3) in breast cancer microenvironment and analyze the their correlation with the clinicopathological features. Methods: The specimens of tumor tissue and adjacent tissues from 30 patients with infiltrative breast cancer who were diagnosed as breast cancer from June 2016 to May 2017 in The First Hospital of Jiaxing were collected, and the specimen were divided into two parts along the center. After embedding and cryosectioning, the expression and distribution of PD-1 and TIM-3 protein in tumor tissues were observed by immunofluorescence staining. Another part of the specimen was cut and digested, and non-continuous density gradient centrifugation was used to extract tumor-infiltrating lymphocytes (TILs), real-time quantitative PCR (qRT-PCR) was used to detect the mRNA expression of PD-1 and TIM-3 in TILs. Meanwhile, the protein expression was determined by Western blotting. The relationship between the expression of PD-1 and TIM-3 and pathological parameters of breast cancer was analyzed with correlation analysis. Results: Immunofluorescence results showed that more PD-1 and TIM-3 positive cells were observed in the tumor tissues compared with the tumor-adjacent tissues. The qRT-PCR showed that the expression of PD-1 and TIM-3 mRNA in TILs were both significantly higher than those in paracancerous tissues (3.09±0.38 vs 1.26±0.23, 3.42±0.31 vs 1.57±0.29, t=4.16, 4.37, both P<0.05). At the protein level, the expression of PD-1 and TIM-3 in tumor tissue lymphocytes(0.66±0.08, 0.80±0.11) was significantly higher than those in cancerous tissues(0.10±0.01, 0.26±0.02) (t=6.79, 4.57, both P<0.05). There were significant differences in the expression of PD-1, TIM-3 mRNA in the TILs between the different tumor histological grades, tumor sizes, lymph node metastasis (t=2.22-2.99, all P<0.05). Correlation analysis showed that there was a significant positive correlation between the expression of PD-1 and TIM-3 in tumor tissues (r=0.616, P<0.01). Conclusions: In the breast cancer microenvironment, PD-1, TIM-3-mediated signaling pathway plays an important role in the occurrence and development of breast cancer, it provides a new basis for the combination therapy of breast cancer.

Descemet Membrane Endothelial Keratoplasty: Safety and Outcomes: A Report by the American Academy of Ophthalmology

PURPOSE

To review the published literature on the safety and outcomes of Descemet membrane endothelial keratoplasty (DMEK) for the surgical treatment of corneal endothelial dysfunction.

METHODS

Literature searches were last conducted in the PubMed and the Cochrane Library databases most recently in May 2017. The searches, which were limited to English-language abstracts, yielded 1085 articles. The panel reviewed the abstracts, and 47 were determined to be relevant to this assessment.

RESULTS

After DMEK surgery, the mean best-corrected visual acuity (BCVA) ranged from 20/21 to 20/31, with follow-up ranging from 5.7 to 68 months. At 6 months, 37.6% to 85% of eyes achieved BCVA of 20/25 or better and 17% to 67% achieved BCVA of 20/20 or better. Mean endothelial cell (EC) loss was 33% (range, 25%-47%) at 6 months. Overall change in spherical equivalent was +0.43 diopters (D; range, -1.17 to +1.2 D), with minimal induced astigmatism of +0.03 D (range, -0.03 to +1.11 D). The most common complication was partial graft detachment requiring air injection (mean, 28.8%; range, 0.2%-76%). Intraocular pressure elevation was the second most common complication (range, 0%-22%) after DMEK, followed by primary graft failure (mean, 1.7%; range, 0%-12.5%), secondary graft failure (mean, 2.2%; range, 0%-6.3%), and immune rejection (mean, 1.9%; range, 0%-5.9%). Overall graft survival rates after DMEK ranged from 92% to 100% at last follow-up. Best-corrected visual acuity after Descemet's stripping endothelial keratoplasty (DSEK) ranged from 20/34 to 20/66 at 9 months. The most common complications after DSEK were graft detachment (mean, 14%; range, 0%-82%), endothelial rejection (mean, 10%; range, 0%-45%), and primary graft failure (mean, 5%; range, 0%-29%). Mean EC loss after DSEK was 37% at 6 months.

CONCLUSIONS

The evidence reviewed supports DMEK as a safe and effective treatment for endothelial failure. With respect to visual recovery time, visual outcomes, and rejection rates, DMEK seems to be superior to DSEK and to induce less refractive error with similar surgical risks and EC loss compared with DSEK. The rate of air injection and repeat keratoplasty were similar in DMEK and DSEK after the learning curve for DMEK.

Lysosomal hydrolase staining of conjunctival impression cytology specimens in keratoconus

PURPOSE

This study sought to assess the feasibility of impression cytology for the determination of conjunctival intracellular lysosomal hydrolase (acid esterase) levels in patients with keratoconus.

METHODS

Twenty-two patients with keratoconus currently enrolled in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study and 22 age-and sex-similar controls underwent impression cytology. Samples were collected from each subject and control pair on the same day. The cells of the respective specimens were fixed immediately and were stained for acid esterase with use of identical batches of fixatives and stains. After staining, the specimens were cleared in xylene for mounting in synthetic resin on glass slides. The acid esterase staining intensity of each specimen was quantified as the percentage of light transmitted with use of an image analysis system (Zeiss). Multiple cells from each specimen were analyzed for each sample collected.

RESULTS

Mixed model analysis was used to account for the subject-control pairings and for the multiple cells from each sample. With this method, the mean light transmission for normal controls (mean = 63.0; standard error [SE] = 3.0) was highly statistically significantly different from that for the keratoconus subjects (mean = 52.4; SE = 3.0) (two-tailed p= 0.0032).

CONCLUSIONS

This study establishes the feasibility of adapting an acid esterase staining technique to conjunctival cells collected via impression cytology. Higher levels of lysosomal enzyme staining in patients with keratoconus have been previously reported by other investigators using full-thickness conjunctival specimens. We also demonstrate the value of using objective microspectrophotometry in measuring lysosomal enzyme staining with impression cytology specimens.

An interleaved T1-T2* imaging sequence for assessing myocardial injury

We developed a sequence by which T1- and T2*-weighted images can be acquired simultaneously and demonstrated its validity for assessing myocardial injury. The interleaved T1-T2* imaging sequence consisted of one preparatory pulse (a 90 degrees pulse) and a gradient-echo imaging sequence with a dynamically variable echo time varying between 4.2 msec for T1-weighted imaging and 15 msec for T2*-weighted imaging. The sequence was tested and validated on isolated blood-perfused pig hearts (n = 4). We found that contrast agent-induced T1 and T2* effects were clearly delineated during the first-pass and steady-state periods of a contrast agent (gadolinium diethylenetriaminopentaacetic acid). With a bolus injection of contrast agent, the maximum changes in T2* signal intensity occur significantly earlier than the changes in T1 signal. We also found that the maximum change in T1 signal intensity during the first pass of contrast agent was significantly greater in a reperfused-infarcted region than in normal regions. The suppression of T2* signal was similar in both regions. At steady state of contrast agent, T2* signal intensities gradually recovered to a significantly higher level in the reperfused-infarcted region than in normal regions. This suggests that the contrast agent diffused into the intracellular space, indicating the loss of cell membrane integrity. As a result, T1 signal intensity was also higher in the reperfused-infarcted myocardium than in normal myocardium. T1- and T2*-weighted images can be acquired simultaneously. The interleaved T1-T2* sequence is useful in assessing myocardial injury.

[Effects of morphine, pethidine and fentanyl on isolated rabbit trachea]

Effects of morphine, pethidine and fentanyl on tension of isolated rabbit trachea were measured by electric field stimulation. Findings obtained were: 1) Morphine 53 mumol.L-1 increased markedly the trachea contraction (P < 0.01); 2) Fentanyl 1.9 mumol.L-1 decreased the trachea contraction (P < 0.05); 3) Pethidine 705 mumol.L-1 not only decreased markedly the trachea contraction (P < 0.01), but also relaxed the trachea; 4) Naloxone 2.2 mumol.L-1 had no influence on the trachea directly (P > 0.05), but reversed the effect of morphine on the trachea. The results indicated that the excitation of morphine receptor in trachea may be one of the mechanisms of the contraction of the trachea.

Variability of laser-evoked potentials: attention, arousal and lateralized differences

We recorded laser-evoked potentials (LEPs) from 20 normal subjects by stimulating the skin with pulses from an infrared CO2 laser. The conduction velocity of the peripheral afferent fibers mediating the LEPs averaged 14.9 m/sec. The amplitude of the LEP components correlated significantly with perceived stimulus intensity. During repetitive constant intensity stimulation, the peak-to-peak LEP amplitude decreased 38% during a distraction task and 42% during drowsiness and was absent during stage 2 sleep, indicating a modulation of responsiveness to laser stimulation during distraction and decreased states of arousal. Normative data revealed considerable intersubject variability in LEP latencies and amplitudes. Analysis of intrasubject lateralized (side-to-side) differences revealed that the relative peak-to-peak amplitude was less variable than that of the N or P components. For clinical applications using 3 S.D.s to define the normal range, a lateral interpeak amplitude difference greater than 28% would suggest focal or lateralized sensory abnormality in an individual patient. Vigilance and attentiveness to the stimuli should be monitored during the acquisition of LEPs.

Double inversion recovery improves water suppression in vivo

It is shown that double inversion recovery used for water suppression can be made much less sensitive to pulse imperfections and to the variations in the relaxation times than a single inversion recovery. This insensitivity results in up to 10-fold improvement in the water suppression in vivo. The excellent water suppression by double inversion recovery is demonstrated experimentally by the in vivo proton spectra obtained from a rat brain.

Case report: primary systemic amyloidosis presenting as breast masses, mammographically simulating carcinoma

A case of primary systemic amyloidosis presenting as bilateral breast masses is described. The mammographic appearance was of multiple ill-defined masses associated with clustered microcalcifications simulating carcinoma. This is the first case of amyloid of breast reported in the radiological literature. Other available literature of breast involvement in systemic amyloidosis is reviewed.

On the use of double-quantum coherence from an AX3 system (protons in lactate) for spectral editing

The suppression of water signals in in vivo proton spectra by means of multiple-quantum filtering can be brought about in several ways. This communication exposes the shortcomings of using purely subtractive filtering techniques to observe signals from metabolites that contain proton couplings of the form AX3.