Growth differentiation factor 15 (GDF15) and semaglutide inhibit food intake and body weight through largely distinct, additive mechanisms.

AIMS: To evaluate whether the potent hypophagic and weight-suppressive effects of growth differentiation factor-15 (GDF15) and semaglutide combined would be a more efficacious antiobesity treatment than either treatment alone by examining whether the neural and behavioural mechanisms contributing to their anorectic effects were common or disparate. MATERIALS/METHODS: Three mechanisms were investigated to determine how GDF15 and semaglutide induce anorexia: the potentiation of the intake suppression by gastrointestinal satiation signals; the reduction in motivation to feed; and the induction of visceral malaise. We then compared the effects of short-term, combined GDF15 and semaglutide treatment on weight loss to the individual treatments. Rat pharmaco-behavioural experiments assessed whether GDF15 or semaglutide added to the satiating effects of orally gavaged food and exogenous cholecystokinin (CCK). A progressive ratio operant paradigm was used to examine whether GDF15 or semaglutide reduced feeding motivation. Pica behaviour (ie, kaolin intake) and conditioned affective food aversion testing were used to evaluate visceral malaise. Additionally, fibre photometry studies were conducted in agouti-related protein (AgRP)-Cre mice to examine whether GDF15 or semaglutide, alone or in combination with CCK, modulate calcium signalling in hypothalamic AgRP neurons. RESULTS: Semaglutide reduced food intake by amplifying the feeding-inhibitory effect of CCK or ingested food, inhibited the activity of AgRP neurons when combined with CCK, reduced feeding motivation and induced malaise. GDF15 induced visceral malaise but, strikingly, did not affect feeding motivation, the satiating effect of ingested food or CCK signal processing. Combined GDF15 and semaglutide treatment produced greater food intake and body weight suppression than did either treatment alone, without enhancing malaise. CONCLUSIONS: GDF15 and semaglutide reduce food intake and body weight through largely distinct processes that produce greater weight loss and feeding suppression when combined.

The CXCR4 inhibitor BL-8040 induces the apoptosis of AML blasts by downregulating ERK, BCL-2, MCL-1 and cyclin-D1 via altered miR-15a/16-1 expression.

CXCR4 is a key player in the retention and survival of human acute myeloid leukemia (AML) blasts in the bone marrow (BM) microenvironment. We studied the effects of the CXCR4 antagonist BL-8040 on the survival of AML blasts, and investigated the molecular mechanisms by which CXCR4 signaling inhibition leads to leukemic cell death. Treatment with BL-8040 induced the robust mobilization of AML blasts from the BM. In addition, AML cells exposed to BL-8040 underwent differentiation. Furthermore, BL-8040 induced the apoptosis of AML cells in vitro and in vivo. This apoptosis was mediated by the upregulation of miR-15a/miR-16-1, resulting in downregulation of the target genes BCL-2, MCL-1 and cyclin-D1. Overexpression of miR-15a/miR-16-1 directly induced leukemic cell death. BL-8040-induced apoptosis was also mediated by the inhibition of survival signals via the AKT/ERK pathways. Importantly, treatment with a BCL-2 inhibitor induced apoptosis and act together with BL-8040 to enhance cell death. BL-8040 also synergized with FLT3 inhibitors to induce AML cell death. Importantly, this combined treatment prolonged the survival of tumor-bearing mice and reduced minimal residual disease in vivo. Our results provide a rationale to test combination therapies employing BL-8040 and BCL-2 or FLT3 inhibitors to achieve increased efficacy of these agents.

Amino acid uptake by isolated renal brush border membrane vesicles in various buffers.

The uptake of amino acids by isolated rat renal brush border membrane vesicles in a modified Krebs-Ringer bicarbonate buffer and a phosphate buffer was compared to the uptake in the standard membrane vesicle buffer, Tris-Hepes-mannitol. The uptake in the modified Krebs-Ringer bicarbonate buffer was similar to that in the Tris-Hepes-mannitol buffer. Removal of the ionic constituents other than NaCl and NaHCO3 in the modified Krebs-Ringer bicarbonate buffer (KCl, CaCl2, KH2PO4 and MgSO4) did not affect the amino acid uptake by the isolated membrane vesicles. The timed uptake of proline under sodium gradient conditions in a phosphate buffer had a markedly dampened overshoot. Kinetic analysis of the initial rate of proline uptake in a phosphate buffer compared to a Tris-Herpes-mannitol buffer showed two entry systems for proline in each buffer with similar Km values, but the maximal rate of transport (V) for each system in the phosphate buffer was much lower than that in the Tris-Hepes-mannitol buffer. From these data, phosphate buffer does not appear to be a suitable medium for the study of amino acid uptake by isolated brush border membrane vesicles.

1,25-Dihydroxyvitamin D3-induced calcium efflux from calvaria is mediated by protein kinase C.

1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is an important regulator of bone metabolism involved in both formation and resorption. Traditionally it was assumed that vitamin D receptors are intracellular. Recent data indicate that vitamin D may also act through a membrane receptor, specifically raising intracellular calcium and inositol 1,4,5 triphosphate. The present study was undertaken to explore further the mechanism(s) of vitamin D-induced bone resorption in cultured bone. 1,25(OH)2D3 induced a dose-dependent increase of calcium efflux from cultured bone. This increase was completely obliterated by inhibition of protein kinase C (PKC) with either staurosporine or calphostin C. In cultured rat calvariae, 1,25(OH)2D3 also induced a dose-dependent translocation of PKC from cytosol to membrane. The activation of PKC by 1, 25(OH)2D3 occurred following a 30-s incubation, peaked at 1 minute, and disappeared by 5 minutes. 1,25(OH)2D3 did not increase cAMP production in similarly cultured calvaria. These results suggest that the action of 1,25(OH)2D3 on calcium flux from cultured bone is mediated, in part, via activation of PKC.

22-Oxacalcitriol does not interfere with parathyroid hormone-induced phosphaturia or cyclic-AMP excretion.

The vitamin D analogue, 22-oxacalcitriol [22-oxa-1,25(OH)2 vitamin D3], has pleiotropic effects similar to or greater than calcitriol but has markedly fewer calcemic and phosphatemic effects. To test the hypothesis that the lesser phosphatemic effect of 22-oxacalcitriol is due, at least in part, to a lack of interference with the phosphaturic effect of parathyroid hormone, acute clearance experiments were performed in parathyroidectomized rats receiving continuous 1-34 parathyroid hormone (PTH) infusion together with 22-oxacalcitriol (200 pmol.100 g body weight-1.min-1) or vehicle. In contrast to the previously reported inhibitory effect of calcitriol on PTH-induced phosphaturia, fractional excretion of phosphorus increased similarly in both groups, from 0.05 +/- 0.01 to 0.26 +/- 0.02 (p < 0.01) in the vehicle-infused animals and from 0.04 +/- 0.01 to 0.24 +/- 0.02 (p < 0.01) in the 22-oxacalcitriol-treated rats (p between groups not significant [n.s.]). Urinary cyclic AMP excretion also increased similarly, from 45.5 +/- 5.2 to 101.6 +/- 21.6 (p < 0.01) and from 45.4 +/- 5.6 to 102.6 +/- 16.7 pmol/min (p < 0.01), respectively (p between groups n.s.). In search for a nongenomic mechanism that might account for the disparate effects of 22-oxacalcitriol and calcitriol, OK cells, which are reminiscent of the mammalian proximal tubule cell, were stimulated with calcitriol and 22-oxacalcitriol and free intracellular calcium concentration was determined. At high concentrations, calcitriol caused a dose-dependent increase in [Ca2+]i; 22-oxacalcitriol had no effect on [Ca2+]i at any concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of down-regulated CHIF mRNA in the pathophysiology of hyperkalemia of acute tubular necrosis.

Acute tubular necrosis (ATN) is associated with hyperkalemia. We have shown that the medulla is the main site of impaired sodium (Na+)/potassium (K+) pump activity in ATN. CHIF, a gene that evokes K+ conductance in oocytes, is regulated in the colon by aldosterone and in the kidney by K+ intake. It is assumed that CHIF has a role in K+ homeostasis. To characterize the impaired K+ handling in ATN, the effect of impaired renal function on CHIF mRNA expression in the kidney and colon was studied. Three groups of rats with glycerol-induced ATN were studied: (1) control group, (2) moderate-ATN group, and (3) severe-ATN group. Serum creatinine levels in the control group were 45+/-2.1 micromol/L; in the moderate-ATN group, 224.8+/-16.9 micromol/L; and in the severe-ATN group, 376.5+/-15.9 micromol/L. In the group with severe ATN, significant hyperkalemia (P < 0.001 v control group) was noted. The expression of CHIF mRNA in relative units (percentage of control) in the moderate-ATN group, in the medulla, papilla, and colon, was 16.3%+/-5.6% (P < 0.001), 94.2%+/-9.3% (P=not significant ), and 165.9%+/-11.1% (P < 0.001); and in the severe-ATN group was 11.1%+/-6.4% (P < 0.001), 73.7%+/-4% (P < 0.001), and 310.8%+/-27.3% (P < 0.001), respectively. These results show that (1) in both moderate and severe ATN, CHIF mRNA is dramatically reduced in the medulla, (2) in severe ATN, CHIF mRNA expression decreases in the papilla, and (3) CHIF mRNA is upregulated in direct relationship to the severity of ATN and to the levels of aldosterone in the colon. These results suggest that the hyperkalemia that occurs in severe ATN stems at least in part from the downregulation of CHIF mRNA in the kidney medulla and papilla. The compensatory increase in colonic CHIF mRNA is not sufficient to maintain normal serum K+ levels.

Cell seeding in porous transplantation devices.

Porous laminated discs of 1.35 cm diameter and thickness of 0.5 cm fashioned from biodegradable polymers were used as scaffolds for the transplantation of isolated cell populations. The distribution of cells seeded in these devices via injection was modelled with a system of dyed polymeric microparticles. Optimization of parameters related to device design and surgical injection conditions was carried out to maximize the device volume effectively employed in cell transplantation. The area of distribution on the top surface of each device was determined by image analysis techniques and used as a measure of the spatial distribution of injected particles. For poly(L-lactic acid) devices of porosity of 0.83 and median pore diameter of 166 microns seeded with 6 microns beads under standard injection conditions, the average surface area of distribution was 44.45% (+/- 3.36%). The device pore size was found to be a crucial determinant of particle distribution, whilst particle size in the range of 1-10 microns was not found to be important for the devices tested. Application of these results to the seeding of hepatocyte suspensions was made.

Homocystine uptake in isolated rat renal cortical tubules.

Isolated rat renal cortical tubules were used to study the nature of homocystine entry into the tubule cell and its transport interactions with cystine and the dibasic amino acids. The uptake of homocystine with time was progressive, reaching a steady state after 60 min. of incubation. Analysis of the intracellular pool after 5 and 30 min. of incubation revealed that virtually all of the transported homocystine had been converted to other metabolites of the transsulfuration pathway. The major metabolite was cystathionine with a somewhat lesser, but still significant amount as S-adenosylhomocysteine. A kinetic analysis showed that two systems for cellular entry of homocysteine existed with a Km1 of 0.17 mM and a Km2 of 7.65 mM. Arginine and lysine inhibited homocystine uptake via the low Km, high affinity system, but appeared not to inhibit the high Km, low affinity system. Cystine inhibited the low Km, high affinity system, but had an indeterminate effect on the high Km, low affinity system. Homocystine inhibited the uptake of cystine, lysine and arginine by isolated rat renal cortical tubules. The inhibition of homocystine on cystine uptake appeared to occur on both the high and low Km system for tubule cell entry of cystine. The data suggest that the low Km system for homocystine transport is shared with cystine and the dibasic amino acids. These data extend the knowledge of homocystine metabolism and provide a rational basis for new approaches to the treatment of homocystinuria.

Early interactions between drug-involved mothers and infants. Within-group differences.

OBJECTIVE: To explore differences in maternal characteristics, mother-infant interaction, and infant development within a group of women who used cocaine, alcohol, and tobacco during pregnancy and their infants. DESIGN: Prospective survey. SETTING: Countywide, voluntary, home-based clinical intervention program. PARTICIPANTS: Thirty-two mother-infant pairs identified through a risk-assessment screen who participated in the program for 1 year. VARIABLES: Maternal characteristics, neonatal characteristics, interactional measures (Nursing Child Assessment Feeding Scale and Home Observation for Measurement of the Environment scale), and developmental assessment (Bayley Scales of Infant Development at 1 year). RESULTS: The majority of women were black, single, and unemployed. Fifteen (47%) of the infants were born prematurely; four (13%) were small for gestational age. Mean Bayley Scales of Infant Development scores were as follows: the mental development index was 99.8, and the psychomotor development index was 102.4. Older mothers (r = .41, P = .04), mothers of higher parity (r = .42, P = .02), and mothers who were more actively involved in the program (r = .41, P = .04) had higher scores on the Nursing Child Assessment Satellite Training Feeding Scale. Mothers who were better educated (r = .49, P = .009) and mothers who were more active in the program (r = .44, P = .02) had higher scores on the Home Observation for Measurement of the Environment scale. Several of the subscales of the Home Observation for Measurement of the Environment scale were significantly associated with scores on the Bayley Scales of Infant Development. CONCLUSIONS: For this group of substance-exposed infants whose mothers were receiving support services, developmental skills at 1 year were age appropriate. Despite drug abuse and poverty, there was some variability in the ability of mothers to provide a developmentally supportive environment for their infants. Those who were better organized to support infant development had infants who performed better on global developmental assessments.

An examination of the relationship between drinking status after treatment and the self-evaluation of the alcoholic.

A repeated measures design examined the relationship between post-treatment drinking status and the alcoholics' evaluation of themselves when sober and when drinking. The self-evaluation ratings of 78 alcoholics in a residential psychotherapeutic treatment program were measured at intake (time 1), and at follow-up, three to six months after treatment (time 2). Four hypotheses were tested which posited: (1) sober self-ratings would be higher at follow-up than at intake; (2) drinking self-ratings would be lower at follow-up than at intake; (3) sober/drinking differences would be greater at follow-up than at intake; and (4) the nondrinkers would evidence more significant differences (in the above) than the drinkers. The t-test yielded a marginally significant sober rating (t (46) = -1.93, p = 0.03). There was a significant time by sober/drinking interaction (F (1,44) = 5.57, = 0.03), but there was no significant group effect. The first three hypotheses were accepted, the fourth was rejected.

Glutamine uptake by rat renal basolateral membrane vesicles.

The presence of a sodium-dependent, saturable uptake process is described in basolateral membranes of rat renal cortex for L-glutamine. Concentration-dependence studies indicate the presence of multiple transport systems with Km1 of 0.032 mM and V1 of 0.028 nmol/mg of protein per min, and Km2 of 17.6 mM and V2 of 17.6 nmol/mg of protein per min. Lysine completely inhibits the high-affinity, low-capacity Km system and partially inhibits the low-affinity, high-capacity system. Cystine and other dibasic amino acids also affect glutamine uptake.

MMPI-2 interpretation and closed-head trauma: cross-validation of a correction factor.

A substantial body of research suggests that the MMPI-2 contains a number of items that are sensitive to closed-head trauma (CHT) and other neurologic conditions. A correction procedure was recommended by Gass (1991) using an index consisting of 14 neurologically sensitive items that were extracted from a predominantly male veteran sample of CHT patients. The generalizability of these correction items was assessed in the present study by investigating the MMPI-2 scoring characteristics of an outpatient referral sample of 54 CHT patients (28 male, 26 female) who had sustained recent and mild head trauma. Their frequency of endorsement of MMPI-2 was contrasted with that of the MMPI-2 normative sample (N = 2,600). Chi-square analyses identified the 15 MMPI-2 items that best differentiated this CHT sample from normal subjects. The results indicate that: (a) unlike those in an inpatient psychiatric sample (n = 524), the MMPI-2 items that best distinguished the CHT Ss from normals consisted of neurologic symptom content; (b) of these 15 items, 10 were included in the 14-item correction (Gass, 1991); and (c) 13 of the 14 correction items effectively discriminated the cross-validation sample of CHT Ss from normals. These findings offer empirical support for the application of the MMPI-2 correction with patients who have mild and recent head trauma.

Visuoconstructive deficit following infarction in the right basal ganglia: a case report and some experimental data.

Visuospatial disorders are typically described as a consequence of right hemisphere, cortical lesions. We report the case of a female with visuoconstructive deficits with an infarct in the right basal ganglia, with no evidence of visual field defect, hemi-inattention, or sensory or motor loss. Using a process approach to obtain additional quantitative data, we showed that her visuoconstructive disorder could not be attributed to a defect in visual perception, per se. All other aspects of her neuropsychologic skills were normal. These findings provide additional support for the role of subcortical structures in spatially-related motor function and for the utility of applying experimental techniques to clarify the nature of deficits.

Accuracy of electronic surveillance of catheter-associated urinary tract infection at an academic medical center.

OBJECTIVE: To develop and validate a methodology for electronic surveillance of catheter-associated urinary tract infections (CAUTIs). DESIGN: Diagnostic accuracy study. SETTING: A 425-bed university hospital. SUBJECTS: A total of 1,695 unique inpatient encounters from November 2009 through November 2010 with a high clinical suspicion of CAUTI. METHODS: An algorithm was developed to identify incident CAUTIs from electronic health records (EHRs) on the basis of the Centers for Disease Control and Prevention (CDC) surveillance definition. CAUTIs identified by electronic surveillance were compared with the reference standard of manual surveillance by infection preventionists. To determine diagnostic accuracy, we created 2 × 2 tables, one unadjusted and one adjusted for misclassification using chart review and case adjudication. Unadjusted and adjusted test statistics (percent agreement, sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV], and κ) were calculated. RESULTS: Electronic surveillance identified 64 CAUTIs compared with manual surveillance, which identified 19 CAUTIs for 97% agreement, 79% sensitivity, 97% sensitivity, 23% PPV, 100% NPV, and κ of .33. Compared with the reference standard adjusted for misclassification, which identified 55 CAUTIs, electronic surveillance had 98% agreement, 80% sensitivity, 99% specificity, 69% PPV, 99% NPV, and κ of .71. CONCLUSION: The electronic surveillance methodology had a high NPV and a low PPV compared with the reference standard, indicating a role of the electronic algorithm in screening data sets to exclude cases. However, the PPV markedly improved compared with the reference standard adjusted for misclassification, suggesting a future role in surveillance with improvements in EHRs.