Quantitative cone contrast threshold testing in patients with differing pathophysiological mechanisms causing retinal diseases

BACKGROUND

Cone contrast threshold testing (CCT) provides quantitative measurements of color and contrast function to reveal changes in vision quality that are not standard endpoints in clinical trials. We utilize CCT to measure visual function in patients with multiple sclerosis (MS), age-related macular degeneration (AMD), epiretinal membrane (ERM), and retinal vein occlusion (RVO).

METHODS

Retrospective data was gathered from 237 patients of the Gavin Herbert Eye Institute. Subjects included 17 patients with MS, 45 patients with AMD, 41 patients with ERM, 11 patients with RVO, and 123 healthy controls. Patients underwent the primary measurement outcome, CCT testing, as well as Sloan visual acuity test and spectral domain optical coherence tomography during normal care.

RESULTS

Color and contrast deficits were present in MS patients regardless of history of optic neuritis. AMD with intermediate or worse disease demonstrated reduced CCT scores. All 3 stages of ERM demonstrated cone contrast deficits. Despite restoration of visual acuity, RVO-affected eyes demonstrated poorer CCT performance than unaffected fellow eyes.

CONCLUSIONS

CCT demonstrates color and contrast deficits for multiple retinal diseases with differing pathophysiology. Further prospective studies of CCT in other disease states and with larger samples sizes is warranted.

Preclinical assessment of [68Ga]Ga-Cell Death Indicator (CDI): a novel hsp90 ligand for positron emission tomography of cell death

BACKGROUND

4-(N-(S-glutathionylacetyl)amino) phenylarsonous acid (GSAO) when conjugated with a bifunctional chelator 2,2'-(7-(1-carboxy-4-((2,5-dioxopyrrolidin-1-yl)oxy)-4-oxobutyl)-1,4,7-triazonane-1,4-diyl)diacetic acid (NODAGA) (hereafter referred to as Cell Death Indicator [CDI]), enters dead and dying cells and binds to 90kDa heat shock proteins (hsp90).

OBJECTIVE

This study assesses stability, biodistribution, imaging, and radiation dosimetry of [68Ga]Ga-CDI for positron emission tomography (PET).

METHODS

Preparation of [68Ga]Ga-CDI was performed as previously described. Product stability and stability in plasma were assessed using high-performance liquid chromatography. Biodistribution and imaging were conducted in ten healthy male Lewis rats at 1 and 2 h following intravenous [68Ga]Ga-CDI injection. Human radiation dosimetry was estimated by extrapolation for a standard reference man and calculated with OLINDA/EXM 1.1.

RESULTS

Radiochemical purity of [68Ga]Ga-CDI averaged 93.8% in the product and 86.7% in plasma at 4 h post-synthesis. The highest concentration of [68Ga]Ga-CDI is observed in the kidneys; [68Ga]Ga-CDI is excreted in the urine, and mean retained activity was 32.4% and 21.4% at 1 and 2 h post-injection. Lower concentrations of [68Ga]Ga-CDI were present in the small bowel and liver. PET CT was concordant and additionally demonstrated focal growth plate uptake. The effective dose for [68Ga]Ga-CDI is 2.16E-02 mSv/MBq, and the urinary bladder wall received the highest dose (1.65E-02mSv/Mbq).

CONCLUSIONS

[68Ga]Ga-CDI is stable and has favourable biodistribution, imaging, and radiation dosimetry for imaging of dead and dying cells. Human studies are underway.

Quantifying Color Vision Changes Associated With Cataracts Using Cone Contrast Thresholds

Purpose

To evaluate effects of age and simulated and real cataractous changes on color vision as measured by the high-definition cone contrast test (CCT).

Methods

Twenty-four healthy volunteers from two cohort studies performed CCT using best-corrected visual acuity, filters, mydriasis, and pinhole correction. Retrospective cross-sectional study of patients seen in eye clinics evaluated the relationship between age and color vision, and age and lens status in 355 eyes. Last, 25 subjects underwent CCT before and after cataract surgery.

Results

CCT scores were most reliable in the nonmydriatic condition without pinhole correction. Progressively dense brown filters produced small decreases in S-cone sensitivity. Linear regression analysis of phakic subjects showed a decline for all cone classes with age. Rate of decline was greater for S-cones (slope = −1.09; 95% confidence interval [CI], −1.30 to 0.86) than M-cones (slope = −0.80; 95% CI, −1.03 to −0.58) and L-cones (slope = −0.66; 95% CI, −0.88 to −0.44). CCT scores increased for S-cones but reduced for L- and M-cones in pseudophakic subjects compared with phakic patients. CCT scores after cataract surgery increased for S-cones, M-cones, and L-cones by 33.0 (95% CI, 8.6 to 57.4), 24.9 (95% CI, 3.8 to 46.0), and 22.0 (95% CI, −3.2 to 47.3), respectively.

Conclusions

CCT assessment allows for clinically practical quantitation of color and contrast vision improvement after cataract surgery and aging patients who note poor vision despite good visual acuity.

Translational Relevance

CCT testing, which quantifies hereditary and acquired color deficiency, can also quantify the degree of cataract severity and, combined with other parameters, can provide more precise guidance for cataract extraction to optimize patient care.

Granulomatous and lymphocytic interstitial lung disease diagnosed by transbronchial lung cryobiopsy

Granulomatous and lymphocytic interstitial lung disease is a pulmonary complication of common variable immune deficiency with significant morbidity and increased mortality. Diagnosis has historically been obtained by surgical lung biopsy as transbronchial biopsy typically yields insufficient tissue for definitive diagnosis from a disease process with a patchy distribution. However, the potential for significant morbidity and mortality with surgical lung biopsy exists, necessitating the development of alternative diagnostic approaches. We present a case of granulomatous and lymphocytic interstitial lung disease confirmed through minimally invasive transbronchial lung cryobiopsy and discuss the role of this modality in diagnosing interstitial lung disease.

Neonatal alloimmune neutropaenia: Experience from an Australian paediatric health service

AIM

To describe the presenting features and investigation findings in infants diagnosed with neonatal alloimmune neutropaenia (NAIN) within an Australian paediatric health network. The secondary aim was to describe the management and resolution of neutropaenia in infants with NAIN.

METHODS

A retrospective cohort study was conducted at Monash Children's Hospital, Melbourne, Australia. Infants referred to the Victorian Transplantation and Immunogenetics Service for evaluation of NAIN were identified and medical records were reviewed. Descriptive statistical analysis of infants' clinical outcomes, investigation findings and management was performed.

RESULTS

Nine infants were diagnosed with NAIN between December 2004 and June 2017. Overall incidence of NAIN was around 1 per 10 000 births. Median gestational age was 38 (range 35-40) weeks and birthweight was 2920 (2300-4445) g. Median age at NAIN work-up was 7 (2-33) days. Prior to investigation for NAIN, median absolute neutrophil count was 0.2 (0.01-0.6) × 10⁹ cells/L. The post-natal ward was the source of presentation in most infants (78%). All except one infant were admitted to a neonatal unit and commenced on intravenous antibiotics (89%). Six infants were asymptomatic but received antibiotics for risk of infection (75%). Granulocyte-colony stimulating factor was administered to 44% of infants due to neutropaenia with presumed or confirmed infection. NAIN resolved at median age of 32 (6-200) days.

CONCLUSIONS

Infants with NAIN frequently presented with severe, unexpected neutropaenia without major infection. Intravenous antibiotic therapy and granulocyte-colony stimulating factor use was common in this cohort.

Outcomes of standardised approach to metabolic bone disease of prematurity

AIM

To assess the current protocol of metabolic bone disease (MBD) at three Monash Health neonatal units (Melbourne, Australia).

METHODS

Retrospective audit of 171 infants born at <32 weeks' gestation over 18 months. Mean gestational age was 28.6 ± 2.1 weeks, and birthweight was 1190 ± 374 g. Risk factors of MBD include intra-uterine growth retardation (n = 33, 19.3%), maternal pre-eclampsia (n = 17, 9.9%), necrotising enterocolitis (n = 9, 5.4%) and medications like methylxanthines (94.2%; mean 54.8 days), diuretics (38.6%; mean 49.2 days) and glucocorticoids (5.3%; mean 35 days).

RESULTS

In total, 84.8% infants had an initial MBD screen (mean age 36.3 days), with 45% having repeated monitoring (mean age 71.9 days), and 14.2% had initial alkaline phosphatase levels >500 U/L, decreasing to 10.1% on follow-up. All infants received additional vitamin D supplementation of 400 IU/day, phosphate of 25.1% (n = 43) and calcium of 19.9% (n = 34). Fractures were identified from clinical documentation in 2.9% (n = 5) of infants. Stratifying into phosphate-treated and untreated groups revealed significant differences (P < 0.001) for gestational age and birthweight: 26.7 ± 1.7 weeks/918 ± 272 g for treated versus 29.2 ± 1.9 weeks/1283 ± 359 g for untreated. In the phosphate-treated group, improvement was seen in mean alkaline phosphatase (pre-treatment 467 ± 204 U/L and post-treatment 342 ± 221 U/L, P < 0.01) and mean phosphate levels (1.8 ± 0.4 vs. 2.2 ± 1.0 mmol/L, P < 0.01). Linear growth difference between phosphate-treated (n = 10) and untreated groups (n = 24) was insignificant at >6 months of age (P = 0.13), although this may reflect limited data.

CONCLUSION

Adequate first-line supplementation with vitamin D and phosphate appeared to improve biochemical markers of MBD, but given the observational nature of this study, further longitudinal/prospective studies are required to confirm these findings.

BDNF rescues BAF53b-dependent synaptic plasticity and cocaine-associated memory in the nucleus accumbens

Recent evidence implicates epigenetic mechanisms in drug-associated memory processes. However, a possible role for one major epigenetic mechanism, nucleosome remodelling, in drug-associated memories remains largely unexplored. Here we examine mice with genetic manipulations targeting a neuron-specific nucleosome remodelling complex subunit, BAF53b. These mice display deficits in cocaine-associated memory that are more severe in BAF53b transgenic mice compared with BAF53b heterozygous mice. Similar to the memory deficits, theta-induced long-term potentiation (theta-LTP) in the nucleus accumbens (NAc) is significantly impaired in slices taken from BAF53b transgenic mice but not heterozygous mice. Further experiments indicate that theta-LTP in the NAc is dependent on TrkB receptor activation, and that BDNF rescues theta-LTP and cocaine-associated memory deficits in BAF53b transgenic mice. Together, these results suggest a role for BAF53b in NAc neuronal function required for cocaine-associated memories, and also that BDNF/TrkB activation in the NAc may overcome memory and plasticity deficits linked to BAF53b mutations.

Radiosynthesis and 'click' conjugation of ethynyl-4-[(18)F]fluorobenzene--an improved [(18)F]synthon for indirect radiolabeling

Reproducible methods for [(18)F]radiolabeling of biological vectors are essential for the development of new [(18)F]radiopharmaceuticals. Molecules such as carbohydrates, peptides and proteins are challenging substrates that often require multi-step indirect radiolabeling methods. With the goal of developing more robust, time saving, and less expensive procedures for indirect [(18)F]radiolabeling of such molecules, our group has synthesized ethynyl-4-[(18)F]fluorobenzene ([(18)F]2, [(18)F]EYFB) in a single step (14 ± 2% non-decay corrected radiochemical yield (ndc RCY)) from a readily synthesized, shelf stable, inexpensive precursor. The alkyne-functionalized synthon [(18)F]2 was then conjugated to two azido-functionalized vector molecules via CuAAC reactions. The first 'proof of principle' conjugation of [(18)F]2 to 1-azido-1-deoxy-β-D-glucopyranoside (3) gave the desired radiolabeled product [(18)F]4 in excellent radiochemical yield (76 ± 4% ndc RCY (11% overall)). As a second example, the conjugation of [(18)F]2 to matrix-metalloproteinase inhibitor (5), which has potential in tumor imaging, gave the radiolabeled product [(18)F]6 in very good radiochemical yield (56 ± 12% ndc RCY (8% overall)). Total preparation time for [(18)F]4 and [(18)F]6 including [(18)F]F(-) drying, two-step reaction (nucleophilic substitution and CuAAC conjugation), two HPLC purifications, and two solid phase extractions did not exceed 70 min. The radiochemical purity of synthon [(18)F]2 and the conjugated products, [(18)F]4 and [(18)F]6, were all greater than 98%. The specific activities of [(18)F]2 and [(18)F]6 were low, 5.97 and 0.17 MBq nmol(-1), respectively.

Removing nonessential central venous catheters: evaluation of a quality improvement intervention

INTRODUCTION

Nonessential central venous catheters (CVCs) should be removed promptly to prevent adverse events. Little is known about effective strategies to achieve this goal. The present study evaluates the effectiveness of a quality improvement (QI) initiative to remove nonessential CVCs in the intensive care unit (ICU).

METHODS

A prospective observational study was performed in two ICUs following a QI intervention that included a daily checklist, education, and reminders. During 28 consecutive days, all CVCs were identified and the presence of ongoing indications for CVC placement was recorded. The proportions of nonessential CVCs and CVC days were compared with pre-intervention proportions and between the participating units. Rates of central line-associated bloodstream infections (CLABSI) were measured separately through Ontario's Critical Care Information System.

RESULTS

One hundred and ten patients and 159 CVCs were reviewed. Eighty-eight (11%) of 820 catheter days showed no apparent indication for CVC placement, and compared with the pre-intervention period, the proportion of patients with any number of nonessential CVC days decreased from 51% to 26% (relative risk 0.51; 95% confidence interval 0.34 to 0.74; P < 0.001). There was no significant difference in the proportion of nonessential catheter days between participating units. Reported rates of CLABSI decreased substantially during the intervention.

DISCUSSION

A checklist tool supported by a multifaceted QI intervention effectively ensured prompt removal of nonessential CVCs in two ICUs.

Trastuzumab use and CNS metastasis in Medicare patients diagnosed with metastatic breast cancer (MBC)

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Background: While trastuzumab was approved in 1998 for treating patients with HER-2-positive MBC, there is little information on its use in the Medicare setting. Methods: We used SEER-Medicare data to examine patterns of trastuzumab use in women diagnosed with MBC . An index date was defined as either the date of diagnosis (stage IV) or of first distant recurrence (stage 0-III). Included patients were diagnosed in 2000–2002, and had their first claim for trastuzumab between their index date and December 31, 2005, the end of the observation period. Patients were divided into those who received trastuzumab as part of their first treatment following their index date (Group A), and those who began trastuzumab after at least one course of chemotherapy (Group B). Chemotherapy agents were grouped into antimicrotubule (vinorelbine, docetaxel, paclitaxel, vincristine), anthracycline (doxorubicin, epirubicin), cyclophosphamide, other, and unknown. Results: 281 patients met the inclusion criteria. Overall, the median (mean) time from the index date to initial chemotherapy and/or trastuzumab treatment was 35 (94) days (range 1–1,587 days). The average duration of trastuzumab use (first to last administration) was 371 days (median 239), during which patients averaged 2.3 trastuzumab claims per month. There were 192 (68%) patients in Group A. The median (mean) time from diagnosis to initial treatment in Group A was 34 (94) days. 64 (33%) received trastuzumab alone, and 121 (63%) received trastuzumab with an antimicrotubule. In Group B (89 patients), the median (mean) time to initial chemotherapy was 41 (92) days. 36 (40%) received anthracycline and/or cyclophosphamide based therapy, 22 (25%) received an antimicrotubule without either an anthracycline or cyclophosphamide. The median (mean) time from initial chemotherapy to initial trastuzumab therapy was 233 (368) days. At that time, 29 (33%) received trastuzumab alone, and 54 (61%) received trastuzumab plus an antimicrotubule. Conclusions: To our knowledge, this is the first study to describe patterns of trastuzumab use in Medicare. When used for metastatic breast cancer, trastuzumab was most often provided soon after diagnosis as part of initial treatment, and usually with an antimicrotubule agent.

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