Injury Pattern Analysis to Optimize Burn Injury Prevention in the Unhoused Community.

Unhoused patients are an overrepresented group in burn injury, and are a uniquely vulnerable population. Current research focuses on the consequences of homelessness on burn outcomes, with little known about the specific circumstances and behaviors leading to burn injury that may represent specific targets for injury prevention efforts. The burn registry at an urban regional burn center was queried for burn admissions in unhoused adults from 2019 to 2022. Registry data pulled included demographics, urine toxicology, mechanism of injury, and injury subjective history. Subjective injury history was reviewed to determine more specific injury circumstances and activities during which accidental burns occurred. Demographic and mechanistic trends in burn admissions were explored via descriptive statistics. Among 254 admissions for burns from the unhoused community, 58.1% of patients were positive for stimulants on admission. Among accidental injuries (69.7%), common circumstances included preparing food or beverages, cooking or using methamphetamine, smoking cannabis or tobacco, bonfires, and candles. A specific common circumstance was lighting a cigarette while handling accelerants (6.7%). Interventions for stimulant abuse, as well as outreach efforts to educate unhoused patients about situational awareness, safe handling of accelerants, safe smoking practices, and safe cooking practices, may be effective tools in reducing burn admissions in this vulnerable population.

Healthcare Worker Characteristics Associated with SARS-CoV-2 Vaccine Uptake in Ireland; a Multicentre Cross-Sectional Study.

The prevention of SARS-CoV-2 acquisition and transmission among healthcare workers is an ongoing challenge. Vaccination has been introduced to mitigate these risks. Vaccine uptake varies among healthcare workers in the absence of vaccine mandates. We investigated engagement with SARS-CoV-2 vaccination among healthcare workers and identified characteristics associated with lower vaccine uptake. This multi-site cross-sectional study recruited n = 1260 healthcare workers in both clinical and non-clinical roles over a three-month period from November 2022. Participants reported their engagement with the primary SARS-CoV-2 vaccination programme and subsequent booster programmes, as well as providing demographic, occupational and personal medical history information. Multivariable linear regression identified characteristics associated with vaccine uptake. Engagement with vaccination programmes was high, with 88% of participants receiving at least one booster dose after primary vaccination course. Younger age and female sex were associated with reduced vaccine uptake. Healthcare workers in non-clinical roles also had reduced vaccine uptake. These findings should inform vaccination strategies across healthcare settings and target populations with reduced vaccine uptake directly, in particular young, female, and non-clinical healthcare workers, both for SARS-CoV-2 and other healthcare-associated vaccine-preventable infections.

Predictors of Clinical Outcomes Following Laparoscopic Colectomy for Traumatic Injury.

BACKGROUND: Laparoscopic colectomy following traumatic injury has been increasingly utilized, but open resection remains the standard of care. Therefore, identifying appropriate candidates for laparoscopy is critically important. This study's purpose was to identify predictors of clinical outcomes in patients undergoing laparoscopic colectomy following traumatic injury. METHODS: The National Trauma Databank was queried for patients undergoing laparoscopic colectomy within 48 hours of admission between 2007 and 2015. Patient, injury, and management characteristics were abstracted. Multivariable regression analyses adjusted for baseline characteristics and identified significant predictors of clinical outcomes. RESULTS: A total of 581 patients satisfied inclusion criteria. The median age was 31 years, 465 (80%) were male, and 321 (55%) sustained penetrating injuries. An ostomy was created in 143 (25%) cases. Multivariable logistic regression showed that significant predictors of mortality included a falling mechanism (odds ratio [OR] 104.917, P = .002), admission tachycardia (OR 5.823, P = .001), admission hypotension (OR 26.089, P < .001), and multi-system injuries like head (OR 1.587, P = .008) and thoracic (OR 1.627, P = .001) injuries. Significant predictors of unplanned reoperation included transverse (OR 7.657, P = .033) and left (OR 17.155, P = .014) colon resections, obesity (OR 24.407, P = .016), and chronic respiratory disease (OR 32.963, P = .018). Ostomy creation was significantly associated with neither mortality nor unplanned reoperation. CONCLUSION: These data suggest that readily identifiable preoperative characteristics are significantly associated with differences in clinical outcomes. Additional research is required to determine if varying treatment based on these qualities can improve outcomes.

Laparoscopy is associated with decreased all-cause mortality in patients undergoing emergency general surgery procedures in a regional health system.

BACKGROUND: The aim of this study was to evaluate the use of laparoscopic surgery for common emergency general surgery (EGS) procedures within an integrated Acute Care Surgery (ACS) network. We hypothesized that laparoscopy would be associated with improved outcomes. METHODS: Our integrated health care system's EGS registry created from AAST EGS ICD-9 codes was queried from January 2013 to October 2015. Procedures were grouped as laparoscopic or open. Standard descriptive and univariate tests were performed, and a multivariable logistic regression controlling for open status, age, BMI, Charlson Comorbidity Index (CCI), trauma tier, and resuscitation diagnosis was performed. Laparoscopic procedures converted to open were identified and analyzed using concurrent procedure billing codes across episodes of care. RESULTS: Of 60,604 EGS patients identified over the 33-month period, 7280 (12.0%) had an operation and 6914 (11.4%) included AAST-defined EGS procedures. There were 4813 (69.6%) surgeries performed laparoscopically. Patients undergoing a laparoscopic procedure tended to be younger (45.7 ± 18.0 years vs. 57.2 ± 17.6, p < 0.001) with similar BMI (29.7 ± 9.0 kg/m2 vs. 28.8 ± 8.3, p < 0.001). Patients in the laparoscopic group had lower mean CCI score (1.6 ± 2.3 vs. 3.4 ± 3.2, p ≤ 0.0001). On multivariable analysis, open surgery had the highest association with inpatient mortality (OR 8.67, 4.23-17.75, p < 0.0001) and at all time points (30-, 90-day, 1-, 3-year). At all time points, conversion to open was found to be a statistically significant protective factor. CONCLUSION: Use of laparoscopy in EGS is common and associated with a decreased risk of all-cause mortality at all time points compared to open procedures. Conversion to open was protective at all time points compared to open procedures.

Direct Comparison of In-Person Versus Virtual Interviews for Complex General Surgical Oncology Fellowship in the COVID-19 Era.

BACKGROUND: In the era of coronavirus disease 2019 (COVID-19), many Complex General Surgical Oncology (CGSO) fellowship programs implemented virtual interviews (VI) during the 2020 interview season. At our institution, we had the unique opportunity to conduct an in-person interview (IPI) prior to the pandemic-related travel restrictions, and a VI after the restrictions were in place. OBJECTIVE: The goal of this study was to understand how the VI model compares with the traditional IPI approach. METHODS: Online surveys were distributed to both groups, collecting feedback on their interview experience. Responses were evaluated using a two-sample t test assuming equal variances. RESULTS: Twenty-three of 26 (88%) applicants completed the survey. Most applicants reported that the interview gave them a satisfactory understanding of the CGSO fellowship (100% IPI, 92% VI) and the majority in both groups felt that the interview experience allowed them to accurately represent themselves (92% and 82%, respectively). All participants in the IPI group felt they were able to get an adequate understanding of the culture of the program, while only 64% in the VI group agreed with that statement (p = 0.02). IPI applicants were more likely to agree that the interview experience was sufficient to allow them to make a ranking decision (92% vs. 54%; p = 0.04). CONCLUSIONS: While the VI modality offers several advantages over the IPI, it still falls short in conveying some of the more subjective aspects of the programs, including program culture. Strategies to provide applicants with better insight into these areas during the VI will be important moving forward.

Allyship in Surgical Residents: Evidence for LGBTQ Competency Training in Surgical Education.

BACKGROUND: Studies have shown poorer health outcomes for people who identify as sexual and/or gender minority (LGBTQ+) compared to heterosexual peers. Our goal was to establish baseline levels of LGBTQ Ally Identity Measure (AIM) scores: (1) Knowledge and Skills, (2) Openness and Support, and (3) Awareness of Oppression of the LGBTQ+ in surgical trainees, and implement a pilot training in LGBTQ + cultural competency. MATERIALS AND METHODS: General surgery residents from a single academic medical center participated in a 2-h educational training developed from the existing Health Care Safe Zone training at our institution. Utilizing the previously validated LGBTQ Ally Identity Measure (AIM), residents responded to 19 items on Likert-type scales from 1 to 5 pretraining and 6 wk posttraining. The residents' perceptions of the utility of the training were also assessed. Data were analyzed by MANOVA, repeated measures MANOVA, and subsequent univariate analysis. RESULTS: 27 residents responded to the pretraining survey (52%), 22 residents participated in the training, and 10 responded at 6 wk posttraining (19%). The average baseline scores were Knowledge and Skills 19.38 ± 4.64, Openness and Support 25.96 ± 4.31, and Awareness of Oppression 17.15 ± 2.20. Participants who identified as women scored 4.46 (95% CI 0.77-8.15) points higher in Openness and Support compared to males. Of those respondents who completed pretraining and posttraining surveys (n = 10), training had a significant effect on AIM scores with an improvement in Knowledge and Skills (P = 0.024) and Openness and Support (P = 0.042). Residents found the training relevant to surgery patient care (71%), increased their competency in LGBTQ + patient care (86%), and all participants indicated they were better LGBTQ allies following the training. CONCLUSIONS: Assessing LGBTQ + allyship in surgical residents, we found that training improved AIM scores over time with significant improvement in the Knowledge and Skills, and Openness and Support scales, suggesting a viable and valuable curriculum focused on sexual and gender identity-related competencies within the graduate medical education for surgical trainees.

Urine and serum S100A8/A9 and S100A12 associate with active lupus nephritis and may predict response to rituximab treatment.

BACKGROUND: Approximately 30% of patients with the systemic autoimmune/inflammatory disorder systemic lupus erythematosus (SLE) develop lupus nephritis (LN) that affects treatment and prognosis. Easily accessible biomarkers do not exist to reliably predict renal disease. The Maximizing SLE Therapeutic Potential by Application of Novel and Systemic Approaches and the Engineering Consortium aims to identify indicators of treatment responses in SLE. This study tested the applicability of calcium-binding S100 proteins in serum and urine as biomarkers for disease activity and response to treatment with rituximab (RTX) in LN. METHODS: S100A8/A9 and S100A12 proteins were quantified in the serum and urine of 243 patients with SLE from the British Isles Lupus Assessment Group Biologics Register (BILAG-BR) study and 48 controls matched for age using Meso Scale Discovery's technology to determine whether they perform as biomarkers for active LN and/or may be used to predict response to treatment with RTX. Renal disease activity and response to treatment was based on BILAG-BR scores and changes in response to treatment. RESULTS: Serum S100A12 (p<0.001), and serum and urine S100A8/A9 (p<0.001) levels are elevated in patients with SLE. While serum and urine S100 levels do not correlate with global disease activity (SLE Disease Activity Index), levels in urine and urine/serum ratios are elevated in patients with active LN. S100 proteins perform better as biomarkers for active LN involvement in patients with SLE who tested positive for anti-double-stranded DNA antibodies. Binary logistic regression and area under the curve analyses suggest the combination of serum S100A8/A9 and S100A12 can predict response to RTX treatment in LN after 6 months. CONCLUSIONS: Findings from this study show promise for clinical application of S100 proteins to predict active renal disease in SLE and response to treatment with RTX.

A PET study comparing receptor occupancy by five selective cannabinoid 1 receptor antagonists in non-human primates.

There is a medical need for safe and efficacious anti-obesity drugs with acceptable side effect profiles. To mitigate the challenge posed by translating target interaction across species and balancing beneficial vs. adverse effects, a positron emission tomography (PET) approach could help guide clinical dose optimization. Thus, as part of a compound differentiation effort, three novel selective CB1 receptor (CB1R) antagonists, developed by AstraZeneca (AZ) for the treatment of obesity, were compared with two clinically tested reference compounds, rimonabant and taranabant, with regard to receptor occupancy relative to dose and exposure. A total of 42 PET measurements were performed in 6 non-human primates using the novel CB1R antagonist radioligand [(11)C]SD5024. The AZ CB1R antagonists bound in a saturable manner to brain CB1R with in vivo affinities similar to that of rimonabant and taranabant, compounds with proven weight loss efficacy in clinical trials. Interestingly, it was found that exposures corresponding to those needed for optimal clinical efficacy of rimonabant and taranabant resulted in a CB1R occupancy typically around ∼20-30%, thus much lower than what would be expected for classical G-protein coupled receptor (GPCR) antagonists in other therapeutic contexts. These findings are also discussed in relation to emerging literature on the potential usefulness of 'neutral' vs. 'classical' CB1R (inverse agonist) antagonists. The study additionally highlighted the usefulness of the radioligand [(11)C]SD5024 as a specific tracer for CB1R in the primate brain, though an arterial input function would ideally be required in future studies to further assure accurate quantitative analysis of specific binding.

Virtual research visits and direct-to-consumer genetic testing in Parkinson's disease.

OBJECTIVE: The purpose of this study was to conduct a proof-of-concept study to evaluate remote recruitment and assessment of individuals ("virtual research visits") with Parkinson's disease who have pursued direct-to-consumer genetic testing. METHODS: Participants in 23andMe's "Parkinson's Research Community" were contacted by 23andMe. Fifty willing participants living in 23 states underwent a remote, standardized assessment including cognitive and motor tests by a neurologist via video conferencing and then completed a survey. Primary outcomes assessed were (a) proportion of participants who completed the remote assessments; (b) level of agreement (using Cohen's kappa coefficient) of patient-reported data with that of a neurologist; and (c) interest in future virtual research visits. RESULTS: The self-reported diagnosis of Parkinson's disease was confirmed in all cases (k = 1.00). The level of agreement for age of symptom onset (k = 0.97) and family history (k = 0.85) was very good but worse for falling (k = 0.59), tremor (k = 0.56), light-headedness (k = 0.31), and urine control (k = 0.15). Thirty-eight (76%) of the 50 participants completed a post-assessment survey, and 87% of respondents said they would be more or much more willing to participate in future clinical trials if they could do research visits remotely. CONCLUSION: Remote clinical assessments of individuals with known genotypes were conducted nationally and rapidly from a single site, confirmed self-reported diagnosis, and were received favorably. Direct-to-consumer genetic testing and virtual research visits together may enable characterization of genotype and phenotype for geographically diverse populations.

Virtual visits for Parkinson disease: A case series.

We sought to characterize recommendations and feedback of patients with Parkinson disease, each offered a free telemedicine consultation with a specialist. Visits consisted of history, neurologic examination, and recommendations. Midway through the program, patients were asked to complete an online satisfaction survey. From August 2012 to May 2013, 55 patients in 5 states (mean age 67.8 years) participated, with 80% of visits conducted from their home. Patients with Parkinson disease were recommended to exercise (86%), change current medication (63%), and add new medication (53%). Thirty-three of 35 consecutive patients completed a survey. Patient satisfaction exceeded 90% for virtually all aspects of the visit measured. Providing care to patients in their homes via telemedicine is feasible, results in changes to care, and is well-received.

In vitro and in vivo evaluation of (11)C-SD5024, a novel PET radioligand for human brain imaging of cannabinoid CB1 receptors.

We recently developed a novel cannabinoid subtype-1 (CB1) receptor radioligand (11)C-SD5024 for brain imaging. This study aimed to evaluate (11)C-SD5024 both in vitro and in vivo and compare it with the other CB1 receptor ligands previously used in humans, i.e., (11)C-MePPEP, (11)C-OMAR, (18)F-MK-9470, and (18)F-FMPEP-d2. In vitro experiments were performed to measure dissociation constant (Ki) in the human brain and to measure the lipophilicity of the five CB1 receptor ligands listed above. In vivo specific binding in monkeys was measured by comparing total distribution volume (VT) at baseline and after full receptor blockade. The kinetics of (11)C-SD5024 in humans were evaluated in seven healthy subjects with compartmental modeling. SD5024 showed Ki=0.47nM, which was at an intermediate level among the five CB1 receptor ligands. Lipophilicity (LogD7.4) was 3.79, which is appropriate for brain imaging. Monkey scans showed high proportion of specific binding: ~80% of VT. In humans, (11)C-SD5024 showed peak brain uptake of 1.5-3 standardized uptake value, which was slightly higher than that of (11)C-OMAR and (18)F-MK-9470. One-compartment model showed good fitting, consistent with the vast majority of brain uptake being specific binding found in the monkey. Regional VT values were consistent with known distribution of CB1 receptors. VT calculated from 80 and 120min of scan data was strongly correlated (R(2)=0.97), indicating that 80min provided adequate information for quantitation and that the influence of radiometabolites was low. Intersubject variability for VT of (11)C-SD5024 was 22%, which was low among the five radioligands and indicated precise measurement. In conclusion, (11)C-SD5024 has appropriate affinity and lipophilicity, high specific binding, moderate brain uptake, and provides good precision to measure the binding. The results suggest that (11)C-SD5024 is slightly better than or equivalent to (11)C-OMAR and that both are suitable for clinical studies, especially those that involve two scans in one day.

In vivo SPECT and ex vivo autoradiographic brain imaging of the novel selective CB1 receptor antagonist radioligand [125I]SD7015 in CB1 knock-out and wildtype mouse.

We aimed to evaluate the novel high-affinity and relatively lipophilic CB(1) receptor (CB(1)R) antagonist radioligand [(125)I]SD7015 for SPECT imaging of CB(1)Rs in vivo using the multiplexed multipinhole dedicated small animal SPECT/CT system, NanoSPECT/CT(PLUS) (Mediso, Budapest, Hungary), in knock-out CB(1) receptor knock-out (CB(1)R-/-) and wildtype mice. In order to exclude possible differences in cerebral blood flow between the two types of animals, HMPAO SPECT scans were performed, whereas in order to confirm the brain uptake differences of the radioligand between knock-out mice and wildtype mice, in vivo scans were complemented with ex vivo autoradiographic measurements using the brains of the same animals. With SPECT/CT imaging, we measured the brain uptake of radioactivity, using %SUV (% standardised uptake values) in CB(1)R-/- mice (n=3) and C57BL6 wildtype mice (n=7) under urethane anaesthesia after injecting [(125)I]SD7015 intravenously or intraperitoneally. The Brookhaven Laboratory mouse MRI atlas was fused to the SPECT/CT images by using a combination of rigid and non-rigid algorithms in the Mediso Fusion™ (Mediso, Budapest, Hungary) and VivoQuant (inviCRO, Boston, MA, USA) softwares. Phosphor imager plate autoradiography (ARG) was performed on 4 µm-thin cryostat sections of the excised brains. %SUV was 8.6±3.6 (average±SD) in CB(1)R-/- mice and 22.1±12.4 in wildtype mice between 2 and 4 h after injection (p<0.05). ARG of identically taken sections from wildtype mouse brain showed moderate radioactivity uptake when compared with the in vivo images, with a clear difference between grey matter and white matter, whereas ARG in CB(1)R(-/-) mice showed practically no radioactivity uptake. [(125)I]SD7015 enters the mouse brain in sufficient amount to enable SPECT imaging. Brain radioactivity distribution largely coincides with that of the known CB(1)R expression pattern in rodent brain. We conclude that [(125)I]SD7015 should be a useful SPECT radioligand for studying brain CB(1)R in mouse and rat disease models.

[¹²5I]SD-7015 reveals fine modalities of CB1 cannabinoid receptor density in the prefrontal cortex during progression of Alzheimer's disease.

The cannabinoid type-1 receptor (CB1R) is one of the most abundant members of the G protein-coupled receptor family in the central nervous system. Once activated by their cognate ligands, endocannabinoids, CB1Rs generally limit the timing of neurotransmitter release at many cortical synapses. Prior studies have indicated the involvement of CB1R in neurodegeneration and in various neuronal insults, with an emphasis on their neuroprotective role. In the present study we used a novel selective CB1R radioligand to investigate regional variations in CB1R ligand binding as a factor of progressive Braak tau pathology in the frontal cortex of Alzheimer's disease (AD) patients. The frontal cortex was chosen for this study due to the high density of CB1Rs and their well-characterized involvement in the progression of AD. Post-mortem prefrontal cortex samples from AD patients from Braak stages I to VI and controls were subjected to CB1R autoradiography with [¹²5I]SD-7015 as radioligand. Regional concentration of [¹²5I]SD-7015, corresponding to, and thereby representing, regional CB1R densities, were expressed in fM/g_tissue. The results show that CB1R density inversely correlates with Braak tau pathology with the following tendency: controls

Nasal changes after presurgical nasoalveolar molding (PNAM) in the unilateral cleft lip nose.

PURPOSE: Nasal reconstruction for patients with unilateral cleft lip and palate (UCLP) is a challenge for the reconstructive surgeon. Presurgical nasoalveolar molding (PNAM) was introduced to reshape the cleft nasal structures prior to lip repair. This study analyzed two-dimensional nasal changes before and after PNAM in patients with complete UCLP. METHODS: Thirty UCLP patients (19 males; 11 females) who received PNAM before lip repair were included in this study. PNAM was applied for 100 days. Nasal casts were obtained before and after PNAM. Frontal and 45° standardized digital photographs were taken from all casts, and a photogrammetric analysis (16 linear, six angular, and two area measurements) was performed. Paired Student's t tests were used to search for differences by time, and time versus side (cleft versus noncleft). RESULTS: Significant reduction of cleft columella deviation with an increase in columella length, nostril height, and axial inclination on the cleft side were recorded. This resulted in an increase in the projection of the nasal tip. The noncleft measurements remained without significant changes. The cleft nostril area increased significantly more than the noncleft side by 90% with PNAM treatment. Significant normal growth changes were observed in nasal width and nasal height. CONCLUSION: A favorable reshaping of the nose after PNAM was achieved, resulting in an improvement in form before lip surgery. These changes lead to improved nasal symmetry before primary lip and nasal reconstruction in UCLP patients.

N-(4-cyanotetrahydro-2H-pyran-4-yl) and N-(1-cyanocyclohexyl) derivatives of 1,5-diarylpyrazole-3-carboxamides showing high affinity for 18 kDa translocator protein and/or cannabinoid receptors.

In order to develop improved radioligands for imaging brain CB(1) receptors with positron emission tomography (PET) based on rimonabant (5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-N-(piperidin-1-yl)-1H-pyrazole-3-carboxamide, 1), we synthesized compounds 9a-s in which the N-piperidinyl ring was replaced with a 4-(4-cyanotetrahydro-2H-pyranyl) or 1-cyanocyclohexyl ring. Such changes were expected to be almost isosteric with 1, confer greater metabolic resistance, and in the case of the 4-(4-cyanotetrahydro-2H-pyranyl) compounds, substantially reduce lipophilicity. One derivative, 1-(2-bromophenyl)-N-(1-cyanocyclohexyl)-5-(4-methoxyphenyl)-4-methylpyrazole-3-carboxamide (9n), showed high affinity (K(i) = 15.7 nM) and selectivity for binding to CB(1) receptors. The corresponding 4-(4-cyanotetrahydro-2H-pyranyl) derivative (9m) also showed quite high affinity for CB(1) receptors (K(i) = 62 nM) but was found to have even higher affinity (K(i) = 29 nM) for the structurally unrelated 18 kDa translocator protein (TSPO). Some other minor structural changes among 9a-s were also found to switch binding selectivity from CB(1) receptors to TSPO or vice versa. These unexpected findings and their implications for the development of selective ligands or PET radioligands for CB(1) receptors or TSPO are discussed in relation to current pharmacophore models of CB(1) receptor and TSPO binding sites.

A novel terminal web-like structure in cortical lens fibers: architecture and functional assessment.

This study describes a novel cytoskeletal array in fiber cells of the ocular lens of the rat and shows its relationship to the classical terminal web of other epithelial tissues. Naive adult Sprague-Dawley rats (n = 28) were utilized. F-actin, fodrin, myosin IIA, and CP49 distribution was assessed in anterior and posterior polar sections. For functional analysis, lenses were cultured with or without cytochalasin-D for 3 hr, then processed for confocal microscopy or assessed by laser scan analysis along sutures. Phalloidin labeling demonstrated a dense mesh of F-actin adjacent to posterior sutural domains to a subcapsular depth of 400 µm. Anterior polar sections revealed a comparable actin structure adjacent to anterior suture branches however, it was not developed in superficial fibers. Fodrin and myosin were localized within the web-like actin apparatus. The data was used to construct a model showing that the cytoskeletal array is located within the blunt, variable-width fiber ends that abut at sutures such that the "terminal web" flanks the suture on either side. Treatment with cytochalasin-D resulted in partial disassembly of the "terminal web" and perturbed cellular organization. Laser scan analysis revealed that cytochalasin-D treated lenses had significantly greater focal variability than control lenses (P = 0.020). We conclude that cortical fibers of rat lenses contain a bipolar structure that is structurally and compositionally analogous to classical terminal webs. The results indicate that the lens "terminal web" functions to stabilize lens fiber ends at sutures thus minimizing structural disorder, which in turn, promotes the establishment and maintenance of lens transparency.

Imaging and quantitation of cannabinoid CB1 receptors in human and monkey brains using (18)F-labeled inverse agonist radioligands.

UNLABELLED: We recently demonstrated that (11)C-MePPEP, a PET ligand for CB(1) receptors, has such high uptake in the human brain that it can be imaged for 210 min and that receptor density can be quantified as distribution volume (V(T)) using the gold standard of compartmental modeling. However, (11)C-MePPEP had relatively poor retest and intersubject variabilities, which were likely caused by errors in the measurements of radioligand in plasma at low concentrations by 120 min. We sought to find an analog of (11)C-MePPEP that would provide more accurate plasma measurements. We evaluated several promising analogs in the monkey brain and chose the (18)F-di-deutero fluoromethoxy analog ((18)F-FMPEP-d(2)) to evaluate further in the human brain. METHODS: (11)C-FMePPEP, (18)F-FEPEP, (18)F-FMPEP, and (18)F-FMPEP-d(2) were studied in 5 monkeys with 10 PET scans. We calculated V(T) using compartmental modeling with serial measurements of unchanged parent radioligand in arterial plasma and radioactivity in the brain. Nonspecific binding was determined by administering a receptor-saturating dose of rimonabant, an inverse agonist at the CB(1) receptor. Nine healthy human subjects participated in 17 PET scans using (18)F-FMPEP-d(2), with 8 subjects having 2 PET scans to assess retest variability. To identify sources of error, we compared intersubject and retest variability of brain uptake, arterial plasma measurements, and V(T). RESULTS: (18)F-FMPEP-d(2) had high uptake in the monkey brain, with greater than 80% specific binding, and yielded less radioactivity uptake in bone than did (18)F-FMPEP. High brain uptake with (18)F-FMPEP-d(2) was also observed in humans, in whom V(T) was well identified within approximately 60 min. Retest variability of plasma measurements was good (16%); consequently, V(T) had a good retest variability (14%), intersubject variability (26%), and intraclass correlation coefficient (0.89). V(T) increased after 120 min, suggesting an accumulation of radiometabolites in the brain. Radioactivity accumulated in the skull throughout the entire scan but was thought to be an insignificant source of data contamination. CONCLUSION: Studies in monkeys facilitated our development and selection of (18)F-FMPEP-d(2), compared with (18)F-FMPEP, as a radioligand demonstrating high brain uptake, high percentage of specific binding, and reduced uptake in bone. Retest analysis in human subjects showed that (18)F-FMPEP-d(2) has greater precision and accuracy than (11)C-MePPEP, allowing smaller sample sizes to detect a significant difference between groups.

Synthesis and in vitro autoradiographic evaluation of a novel high-affinity radioiodinated ligand for imaging brain cannabinoid subtype-1 receptors.

There is strong interest to study the involvement of brain cannabinoid subtype-1 (CB1) receptors in neuropsychiatric disorders with single photon emission computed tomography (SPECT) and a suitable radioligand. Here we report the synthesis of a novel high-affinity radioiodinated CB1 receptor ligand ([125I]8, [125I]1-(2-iodophenyl)-4-cyano-5-(4-methoxyphenyl)-N-(piperidin-1-yl)-1H-pyrazole-3-carboxylate, [125I]SD7015). By autoradiography in vitro, [125I]8 showed selective binding to CB1 receptors on human brain postmortem cryosections and now merits labeling with iodine-123 for further evaluation as a SPECT radioligand in non-human primate.

Aberrant basal fiber end migration underlies structural malformations in a streptozotocin-induced diabetic rat model.

This study characterized early structural changes at posterior fiber ends in the crystalline lens after diabetic induction. Wistar rats (n = 49), randomized into one naïve control group and four experimental groups, were rendered diabetic via streptozotocin injection. Animals were euthanized at 1 week intervals, blood glucose levels recorded and lenses were evaluated grossly, by SEM and by confocal microscopy. Scoring Indices were developed to assess structural alterations and for statistical correlations between the scores and the duration of hyperglycemic exposure as well as blood glucose levels. Average blood glucose levels increased progressively from 98.5 mg/dL (controls) to 331.4 mg/dL (4 weeks). Diabetic lenses displayed abnormal suture sub-branches and opacity formation beginning late in the first week post-injection and rapidly progressing in severity through four weeks. SEM analyses showed gradual elongation of fiber ends and filopodia which comprised a disorganized configuration and a loss of recognizable migration patterns. Structural alterations culminated in foci of fiber degeneration by the third to fourth weeks. The F-actin distribution at basal fiber ends was significantly altered as compared to naïve controls. Cadherin distribution was altered as compared to controls, but largely at later time points. The grading system clearly shows increased structural compromise with elevated blood glucose levels in streptozotocin-induced diabetes. Further, although the initial rise in blood glucose levels was associated with pathological changes, their progression depended to a larger extent on continued hyperglycemic exposure. The data suggests that hyperglycemia initially disrupts fiber end migration, resulting in structural alterations and eventual fiber degeneration.