Antitumour activity of S-p-bromobenzylglutathione cyclopentyl diester in vitro and in vivo. Inhibition of glyoxalase I and induction of apoptosis

The glyoxalase I inhibitor diester, S-p-bromobenzyl-glutathione cyclopentyl diester (BrBzGSHCp2), inhibited the growth of human leukaemia 60 (HL60) cells in vitro. The median growth inhibitory concentration GC50 value of BrBzGSHCp2 was 4.23 +/- 0.001 microM (n = 21), and the median toxic concentration TC50 value was 8.86 +/- 0.01 microM (n = 21). BrBzGSHCp2 inhibited DNA synthesis in the third hr of incubation: the median inhibitory concentration IC50 value was 6.11 +/- 0.02 microM (n = 8). Incubation of HL60 cells with 10 microM BrBzGSHCp2 delivered the diester into cells: de-esterification of the diester there in lead to formation of the S-p-bromobenzylglutathione, inhibition of glyoxalase I activity in situ, increase in the methylglyoxal concentration after 1 hr, and induction of apoptosis after 6 hr. BrBzGSHCp2 (50-200 mg/kg) also inhibited the growth of murine adenocarcinoma 15A in vivo. Glyoxalase I inhibitor diesters may, therefore, inhibit tumour growth by inducing the accumulation of methylglyoxal in tumour cells, and induction of apoptosis.

High titers of antibodies inhibiting the binding of envelope to human cells correlate with natural resolution of chronic hepatitis C

Most cases of hepatitis C virus (HCV) infection result in chronic disease; however, a very small fraction of patients naturally clear the virus and resolve chronic hepatitis. In an attempt to correlate immune response with chronic disease resolution, we compared the antibody response in patients with different outcomes of the infection. Antibody responses to HCV structural proteins were assessed in 34 patients originally diagnosed with acute hepatitis. Five cases resolved acute infection, 22 developed chronic hepatitis, and 7 naturally resolved chronic hepatitis C. To estimate HCV neutralizing antibodies we used the neutralization of binding (NOB) assay, which evaluates inhibition of the envelope-2 protein binding to human cells. Enzyme-linked immunosorbent assay was used for the quantitative assessment of serum antibodies. The presence of HCV RNA was ascertained by reverse transcription-polymerase chain reaction. In 6 of 7 patients naturally recovered from chronic hepatitis C, the emergence and the persistence (for more than 3 months) of high serum titers (>1/600) of NOB antibodies coincided with virus clearance and clinical resolution of hepatitis. NOB antibody activity was observed in only 2 of 5 patients recovered from acute hepatitis C. Chronic patients who did not show any resolution during the course of the study developed low or no NOB antibodies. Because of the correlation between prolonged high NOB titers and natural resolution of chronic hepatitis C, vaccination or passive immunization aimed at high titers of NOB antibodies may be valuable new therapeutic approaches for chronic hepatitis C.

Single-Cell Characterization of the Immune Microenvironment of Melanoma Brain and Leptomeningeal Metastases

PURPOSE

Melanoma brain metastases (MBM) and leptomeningeal melanoma metastases (LMM) are two different manifestations of melanoma CNS metastasis. Here, we used single-cell RNA sequencing (scRNA-seq) to define the immune landscape of MBM, LMM, and melanoma skin metastases.

EXPERIMENTAL DESIGN

scRNA-seq was undertaken on 43 patient specimens, including 8 skin metastases, 14 MBM, and 19 serial LMM specimens. Detailed cell type curation was performed, the immune landscapes were mapped, and key results were validated by IHC and flow cytometry. Association analyses were undertaken to identify immune cell subsets correlated with overall survival.

RESULTS

The LMM microenvironment was characterized by an immune-suppressed T-cell landscape distinct from that of brain and skin metastases. An LMM patient with long-term survival demonstrated an immune repertoire distinct from that of poor survivors and more similar to normal cerebrospinal fluid (CSF). Upon response to PD-1 therapy, this extreme responder showed increased levels of T cells and dendritic cells in their CSF, whereas poor survivors showed little improvement in their T-cell responses. In MBM patients, therapy led to increased immune infiltrate, with similar T-cell transcriptional diversity noted between skin metastases and MBM. A correlation analysis across the entire immune landscape identified the presence of a rare population of dendritic cells (DC3) that was associated with increased overall survival and positively regulated the immune environment through modulation of activated T cells and MHC expression.

CONCLUSIONS

Our study provides the first atlas of two distinct sites of melanoma CNS metastases and defines the immune cell landscape that underlies the biology of this devastating disease.

Safety of low-dose radiocontrast for interventional AV fistula salvage in stage 4 chronic kidney disease patients

The Dialysis Outcomes Quality Initiative emphasizes increasing arteriovenous fistula prevalence, by promoting referral for fistula creation in patients with stage 4 chronic kidney disease (CKD). The aim is to provide an optimal access for initiation of dialysis, thus avoiding central venous catheter use. The endovascular management of nonmaturing fistulas is more complicated in these patients, where the expected benefit of catheter avoidance must be weighed against the risk of contrast induced nephropathy (CIN). This study reports on the safety of a low-dose radiocontrast regimen, used in performing endovascular fistula salvage procedures in patients with stage 4 CKD. All consecutive endovascular procedures performed over a 2-year period in patients with stage 4 CKD and nonmaturing access were identified. Data collected included the type of procedure, contrast volume per procedure, pre, 2- and 7-day creatinine, need for acute dialysis, and the type of access used to initiate dialysis. Total of 65 procedures were performed in 34 patients. The mean contrast volume was 7.8 ml per procedure. The incidence of CIN (25% increase in serum creatinine) was 4% at 2 days and 4.6% at 1 week. All values returned to baseline within 2 weeks, and no patient required acute dialysis. Among the 33 patients with nonmaturing fistulas, 20 initiated dialysis during the follow-up period, 15 (75%) using their fistula, and five (25%) using a catheter. This study demonstrates that in patients with advanced CKD, fistulas can be successfully salvaged using small contrast volumes with a low incidence of CIN.

Proteomic Analysis of CSF from Patients with Leptomeningeal Melanoma Metastases Identifies Signatures Associated with Disease Progression and Therapeutic Resistance

PURPOSE

The development of leptomeningeal melanoma metastases (LMM) is a rare and devastating complication of the late-stage disease, for which no effective treatments exist. Here, we performed a multi-omics analysis of the cerebrospinal fluid (CSF) from patients with LMM to determine how the leptomeningeal microenvironment shapes the biology and therapeutic responses of melanoma cells.

EXPERIMENTAL DESIGN

A total of 45 serial CSF samples were collected from 16 patients, 8 of these with confirmed LMM. Of those with LMM, 7 had poor survival (<4 months) and one was an extraordinary responder (still alive with survival >35 months). CSF samples were analyzed by mass spectrometry and incubated with melanoma cells that were subjected to RNA sequencing (RNA-seq) analysis. Functional assays were performed to validate the pathways identified.

RESULTS

Mass spectrometry analyses showed the CSF of most patients with LMM to be enriched for pathways involved in innate immunity, protease-mediated damage, and IGF-related signaling. All of these were anticorrelated in the extraordinary responder. RNA-seq analysis showed CSF to induce PI3K/AKT, integrin, B-cell activation, S-phase entry, TNFR2, TGFβ, and oxidative stress responses in the melanoma cells. ELISA assays confirmed that TGFβ expression increased in the CSF of patients progressing with LMM. CSF from poorly responding patients conferred tolerance to BRAF inhibitor therapy in apoptosis assays.

CONCLUSIONS

These analyses identified proteomic/transcriptional signatures in the CSF of patients who succumbed to LMM. We further showed that the CSF from patients with LMM has the potential to modulate BRAF inhibitor responses and may contribute to drug resistance.See related commentary by Glitza Oliva and Tawbi, p. 2083.

The effect of dietary wheat middlings and enzyme supplementation. 1. Late egg production efficiency, egg yields, and egg composition in two strains of Leghorn hens

A study was conducted to test the effects of wheat middlings (WM) with and without enzyme (xylanase and protease) supplementation on late egg production (EP), egg yields, and egg composition in two strains of Leghorn hens (DeKalb Delta and Hisex White). Six diets were randomly assigned to 300 birds (150 birds per strain) from 42 to 60 wk of age. Diet 1 was a corn-soybean meal control, Diets 2 and 3 had 8 and 16% WM, respectively, Diet 4 had 8% WM with 0.1% enzyme, and Diets 5 and 6 had 16% WM with 0.1 and 0.2% enzyme, respectively. Each dietary treatment was replicated five times per strain. Egg production, feed consumption (FC), feed efficiency (FE), percentage dirty eggs, specific gravity (SP), egg weight (EW), and egg mass (EM) were measured on a weekly basis. Egg components (EC) were measured biweekly and birds were weighed every 4 wk. Egg production was not significantly affected by diet, with averages of 83.7, 85.7, 84.1, 84.2, 82.3, and 84.0% for Diets, 1, 2, 3, 4, 5, and 6, respectively. Strain had a marked effect on FC, with Hisex having higher FC than DeKalb hens. Feed consumption also showed a significant diet by strain effect, being lower for Hisex hens fed diets with enzyme compared to diets without enzyme. DeKalb hens had better FE than Hisex hens, and addition of enzyme to 16% WM improved it further. Strain and diet had a significant effect on EC with higher percentages of albumen and yolk for diets with enzyme and for DeKalb hens. Percentage shell was lower for DeKalb hens than for Hisex hens but was not affected by diet. There was also a significant increase in EW for Diets 4 (63.1 g), 5 (63.8 g), and 6 (63.2 g) compared to Diets 1 (62.1 g), 2 (62.4 g), and 3 (63.0 g), with DeKalb hens showing an increase with Diet 5 compared to Hisex hens. Egg mass improved with the higher rate of enzyme in 16% WM diet compared to the lower enzyme level. Specific gravity declined with enzyme supplementation in WM diets. Eggs from DeKalb hens had lower SP than those from Hisex hens for all diets. Percentage dirty eggs did not differ significantly among treatments but was higher for the Hisex strain than for the DeKalb strain. There were no differences in BW between the two strains of hens or among diets. Adding protease and xylanase to diets rich in fiber can improve the egg output without affecting production parameters.

Methionine and cystine requirements of slow- and fast-feathering male broilers from zero to three weeks of age

Two experiments were conducted with fast- (Ross x 3F8) and slow- (Ross x 308) feathering broiler males from 0 to 3 wk of age to determine Met and Cys requirements. A corn-soybean meal basal diet was formulated to be deficient in Met and Cys but was adequate in all other nutrients (22.0% CP; 3,050 kcal ME/kg). In experiment 1, diets contained 0.50% dietary Cys with 0.35, 0.40, 0.45, and 0.50% total Met. Feed conversion (FC) of slow- and fast-feathering males improved in a similar manner to 0.50% Met (linear, P < 0.05). Nitrogen retention measured from 20 to 21 d of age optimized at 0.46% Met (quadratic, P < 0.01), regardless of feathering rate. Experiment 2 examined the response to feeding 0.35, 0.40, 0.45, and 0.50% total Cys in diets having total Met at 0.45%. Increasing Cys improved FC that optimized at 0.40% with fast-feathering birds (quadratic, P < 0.01), whereas slow-feathering broilers were not responsive. Nitrogen retention measured from d 20 to 21 did not indicate a difference attributable to feathering but a Cys optimization at 0.43% with both broiler sources. Present experimentation indicates a Met requirement approximating 0.50% is appropriate for broilers 0 to 3 wk of age, regardless of feather rate; however, the estimated Cys requirement for slow-feathering males (0.39%) was less than for fast-feathering (0.44%) males.

The effect of dietary wheat middlings and enzyme supplementation II: apparent nutrient digestibility, digestive tract size, gut viscosity, and gut morphology in two strains of leghorn hens

An experiment was conducted with two strains of Leghorn hens, DeKalb Delta (D) and Hisex White (H), to investigate the effect of a commercial poultry enzyme preparation (EZ; xylanase plus protease) on the digestibility of protein, fat, Ca, and P and to determine any changes in the relative size of the digestive tract, gut morphology, and gut viscosity (GV) of birds fed wheat middlings (WM) over an 18-wk period. Three hundred birds (150 birds per strain) were randomly assigned to six diets: Diet 1, control (corn-soybean); Diets 2 and 3, 8% and 16% WM, respectively; Diet 4, 8% WM and 0.1% enzyme (EZ); and Diets 5 and 6, 16% WM and 0.1% and 0.2% EZ, respectively. There were five replicates per diet per strain. At 50 wk, protein digestibility increased significantly with supplementation of EZ, but, at 60 wk, all responses were similar. Protein digestibility was greater in DeKalb Deltas for WM with EZ compared with Hisex on the same treatment. Fat digestibility was greater for Diet 1 than the other diets at 50 wk but showed a similar response at 60 wk. The H strain showed a reduction in fat digestibility with WM diets with EZ. The control diet showed greater Ca digestibility than the other diets at 50 wk but did not differ at 60 wk. Phosphorus digestibility increased significantly for WM diets with or without EZ at 60 wk. Intestinal weight was significantly higher for WM with or without EZ at 50 wk, but was equal to the control diet at 60 wk. At 60 wk, gizzard weights (GW) were also lower in birds fed WM and WM with EZ compared with birds fed the control, but GV was not affected by dietary treatments. Histological observations on jejunum of birds fed WM without EZ showed shortening, thickening, and atrophy of the villi, all of which improved when EZ was included in the diet. Availability of some nutrients in WM diets was improved with supplementation of enzyme. Gastrointestinal (GI) tract and organ size were increased, and gut morphology appeared to be improved.

Clinical Utility of Magnetic Resonance Thermal Imaging (MRTI) For Realtime Guidance of Deep Hyperthermia

A critical need has emerged for volumetric thermometry to visualize 3D temperature distributions in real time during deep hyperthermia treatments used as an adjuvant to radiation or chemotherapy for cancer. For the current effort, magnetic resonance thermal imaging (MRTI) is used to measure 2D temperature rise distributions in four cross sections of large extremity soft tissue sarcomas during hyperthermia treatments. Novel hardware and software techniques are described which improve the signal to noise ratio of MR images, minimize motion artifact from circulating coupling fluids, and provide accurate high resolution volumetric thermal dosimetry. For the first 10 extremity sarcoma patients, the mean difference between MRTI region of interest and adjacent interstitial point measurements during the period of steady state temperature was 0.85°C. With 1min temporal resolution of measurements in four image planes, this non-invasive MRTI approach has demonstrated its utility for accurate monitoring and realtime steering of heat into tumors at depth in the body.

Directionally selective motion detection in the sustaining fibers of the crayfish optic nerve: linear and nonlinear mechanisms

1. Directional selectivity of crayfish sustaining fibers was examined with drifting sine wave gratings and with intracellular and extracellular recordings. Directionality was measured for variations in stimulus contrast, spatial frequency, and temporal frequency. 2. Sustaining fibers exhibit directional selectivity in the magnitude of the compound postsynaptic potential (PSP), the impulse frequency modulation response, and the mean firing rate. The mean synaptic potential is insensitive to direction. The directionality of the mean impulse rate appears to arise by rectification in the voltage-to-impulse transduction. 3. The preferred directions of three identified sustaining fibers are similar to those of head-down optomotor neurons to which these sustaining fibers project. 4. The modulatory response, elicited by gratings drifting in the preferred direction, increased linearly with contrast until saturation (typically at a contrast of 0.5), where maximum directional selectivity obtains. 5. The magnitude of the directional response is a band-pass function of spatial and temporal frequency and exhibits reversal of directionality (i.e., aliasing) at high spatial and temporal frequencies. The results imply a spatial sampling interval of 4.5 degrees and a temperature-dependent inhibitory delay of 40-90 ms. The PSP modulation response shares several features with that of neighboring tangential (Tan1) neurons. 6. A qualitative model is proposed for the transformation of a phase-sensitive, linear directional response to a phase-insensitive and nonlinear time-averaged response, based on the functional connections from Tan1 neurons to sustaining fibers to optomotor neurons. The model includes a threshold rectification, a synaptic band-pass filter, and differences in temporal phase among converging modulatory signals.

HDAC11 activity contributes to MEK inhibitor escape in uveal melanoma

We previously demonstrated that pan-HDAC inhibitors could limit escape from MEK inhibitor (MEKi) therapy in uveal melanoma (UM) through suppression of AKT and YAP/TAZ signaling. Here, we focused on the role of specific HDACs in therapy adaptation. Class 2 UM displayed higher expression of HDACs 1, 2, and 3 than Class 1, whereas HDACs 6, 8, and 11 were uniformly expressed. Treatment of UM cells with MEKi led to modulation of multiple HDACs, with the strongest increases observed in HDAC11. RNA-seq analysis showed MEKi to decrease the expression of multiple HDAC11 target genes. Silencing of HDAC11 significantly reduced protein deacetylation, enhanced the apoptotic response to MEKi and reduced growth in long-term colony formation assays across multiple UM cell lines. Knockdown of HDAC11 led to decreased expression of TAZ in some UM cell lines, accompanied by decreased YAP/TAZ transcriptional activity and reduced expression of multiple YAP/TAZ target genes. Further studies showed this decrease in TAZ expression to be associated with increased LKB1 activation and modulation of glycolysis. In an in vivo model of uveal melanoma, silencing of HDAC11 limited the escape to MEKi therapy, an effect associated with reduced levels of Ki67 staining and increased cleaved caspase-3. We have demonstrated a novel role for adaptive HDAC11 activity in UM cells, that in some cases modulates YAP/TAZ signaling leading to MEKi escape.

The effect of insulin intensification in children and young persons with Type 1 diabetes differs in relation to ethnic group; a prospective observational study

AIMS

We prospectively evaluated the effect of insulin intensification on glycaemic control and lipid levels in children and young persons with Type 1 diabetes in relation to ethnicity.

METHODS

In the first 2 years of a 3-year observation period, as part of routine clinical care, 231 children and young persons (40% white, 28% South Asian, 32% black) from a single clinic were offered intensive insulin therapy. After 2 years, 222 were on intensive therapy and their data were compared between ethnic groups at the end of year 3.

RESULTS

We observed ethnic differences in HbA(1c) levels during the study [study beginning and end: white children and young persons 77 and 70 mmol/mol (9.2 and 8.6%) vs. South Asian 72 and 68 mmol/mol (8.7 and 8.4%) vs. black 83 and 79 mmol/mol (9.7 and 9.4%), P-value for ANCOVA = 0.007]. By study end, South Asians had the lowest HDL cholesterol (2.0 vs. 1.4 vs. 1.6 mmol/l, P-value = 0.03) and highest triglyceride levels (0.9 vs. 1.8 vs. 1.0 mmol/l, P-value = 0.001). In linear mixed modelling, after adjustment for socio-economic deprivation and other covariates: (1) black ethnicity was associated with poorer glycaemic control (P < 0.001) and (2) South Asian ethnicity was associated with higher triglyceride levels (P < 0.001), independent of HbA(1c).

CONCLUSIONS

The effect of insulin intensification on glycaemic control and lipid profile in children and young persons with Type 1 diabetes differs in relation to ethnic group.

Spironolactone causes a rapid down regulation of sigma recognition sites in guinea pig brain and liver

The effect of dosing guinea pigs with spironolactone (100 mg/kg twice daily for 3 days) upon the sigma recognition site labelled with [3H]-DTG was investigated. Animals were dosed with 100 mg/kg spironolactone twice a day for 3 days. Spironolactone treatment caused a decrease in sigma radioligand binding in membranes prepared from liver and brain but not in adrenals or testes. Saturation analysis of [3H]-DTG radioligand binding in the brain indicated that the decrease in specifically bound [3H]-DTG binding was due to a reduction in receptor number with no change in affinity. This method for the selective depletion of brain and liver sigma recognition sites will provide a useful tool for exploring the functional significance of this site.

Risk of chronic kidney disease in people living with HIV by tenofovir disoproxil fumarate (TDF) use and baseline D:A:D chronic kidney disease risk score

OBJECTIVES

To assess the risk of chronic kidney disease (CKD) associated with tenofovir disoproxil fumarate (TDF) use by baseline D:A:D CKD risk score.

METHODS

Adult antiretroviral therapy (ART)-naïve people living with HIV (PLWH) initiating treatment, with estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m2 , were identified in the OPERA cohort. CKD was defined as two or more consecutive eGFR < 60 mL/min/1.73 m2 , > 90 days apart. Associations between TDF use, baseline D:A:D CKD risk and incident CKD were assessed with incidence rates (IRs; Poisson regression) and adjusted pooled logistic regression. The impact of pharmacoenhancers on the observed association between TDF and CKD was also evaluated.

RESULTS

Of 9802 PLWH included, 6222 initiated TDF and 3580 did not (76% and 79% low D:A:D CKD risk, respectively). Overall, 125 CKD events occurred over 24 382 person-years of follow-up. Within strata of D:A:D CKD risk score, IRs were similar across TDF exposure, with high baseline CKD risk associated with highest incidence. Compared with the low-risk group without TDF, there was no statistical difference in odds of incident CKD in the low-risk group with TDF (adjusted odds ratio = 0.55, 95% confidence interval: 0.19-1.54). Odds of incident CKD did not differ statistically significantly by pharmacoenhancer exposure, with or without TDF.

CONCLUSIONS

In this large cohort of ART-naïve PLWH, incident CKD following ART initiation was infrequent and strongly associated with baseline CKD risk. TDF-containing regimens did not increase the odds of CKD in those with a low baseline D:A:D CKD risk, the largest group of ART-naïve PLWH, and may remain a viable treatment option in appropriate settings.

Patterns of blood supply to the gastric mucosa. A comparative study revealing an end-artery model

The form of the gastric arterial supply to the mucosa has been studied in dog, swine, ferret, cat, guinea-pig, rabbit and rhesus monkey. In all these species, the bore of vessels in the submucous plexus diminished from body to pylorus, though this was most marked in the guinea-pig and rabbit. The plexus was also continuous across the pylorus with duodenal vessels. Thus the well known poverty of vascularity in distal parts of the human stomach is shared by other species and is unlikely to be a contributory factor to the initiation of peptic ulcer, a disease limited to man. In dog, swine, ferret and cat, as in man, the primary (largest) and secondary (smaller) components of the plexus lay entirely in the submucosa. In the cat, there was a secondary plexus of much smaller vessels deep to the muscularis mucosae. In the guinea-pig, rat, rabbit and monkey, both plexuses were mostly embedded within the muscularis mucosae. As a result, mucosal arteries had two modes of origin: (a) the first, in which they did not pass through the muscularis mucosae as exemplified in the cat, and (b) the second, where they did pass through muscularis mucosae as exemplified by the dog, ferret and swine; in other species, they passed through part of the muscularis mucosae. Areas of mucosa supplied by a single mucosal artery were measured, and ranged widely from the smallest in the cat to the largest in the dog. These features do not seem to have been reported previously, and may be associated with as yet undiscovered functional mechanisms of the muscularis mucosae. Mucosal arteries of extramural origin were found to occur occasionally in the guinea-pig and rabbit, and hence these may provide an experimental model of the pattern existing in man.