Renal ammoniagenic response to chronic acid loading: role of glucocorticoids

1988 ◽  
Vol 254 (1) ◽  
pp. F134-F138 ◽  
Author(s):  
T. C. Welbourne ◽  
G. Givens ◽  
S. Joshi
Keyword(s):  
Production Rate ◽  
Low Dose ◽  
High Dose ◽  
Ammonium Excretion ◽  
Ammonia Production ◽  
Total Ammonia ◽  
High Doses ◽  
Reduced Rate ◽  
Acid Loading

Adrenalectomized (ADX) animals exhibit a blunted renal response to chronic acid loading. To determine whether this response truly reflects impaired renal ammoniagenesis from glutamine, urinary ammonium excretion was compared with acid intake in ADX, intact, and ADX rats supplemented with either a low dose (4 micrograms.100 g-1.day-1) or a high dose (40 micrograms.100 g-1.day-1) of triamcinolone. ADX rats consumed similar amounts of acid as did intact controls yet excreted only 37% of the load as ammonium; in contrast intact controls returned 86% and triamcinolone-supplemented animals returned 98 and 88% for low and high doses, respectively. Nor could the reduced ammonium excretion be attributed to increased renal venous release, since total ammonia production, the sum of renal venous and urine ammonium, was reduced to 49% of the intact controls; low- and high-dose triamcinolone restored and markedly increased the production rate. Underlying the impaired ammonia production rate in ADX rats was a reduced rate of glutamine extraction, 350 +/- 49 vs. 896 +/- 102 and 1,260 +/- 247 and 1,448 +/- 112 nmol.min-1.100 g-1 for intact and low and high doses, respectively. Unlike intact acidotic and glucocorticoid-supplemented ADX acidotic rats, glutamine extraction was disassociated from the delivered glutamine load consonant with the role of glucocorticoid in coupling cellular glutamine transport to its metabolic utilization.

scholarly journals Evaluation of the BDNF, NGF, NT3 and NT4 Genes Expressions in the Brains of Neonatal Mice with Hypothyroidism

2017 ◽  
Vol 7 (1) ◽  
pp. 171
Author(s):  
Hamid Reza Adeli Bhroz ◽  
Kazem Parivar ◽  
Iraj Amiri ◽  
Nasim Hayati Roodbari
Keyword(s):  
Dose Group ◽  
Low Dose ◽  
Pure Water ◽  
Intervention Group ◽  
Control Group ◽  
High Dose ◽  
Endocrine Glands ◽  
Blood Samples ◽  
High Doses ◽  
The Brain

Background and Aim: Thyroid is one of the endocrine glands, (T3 and T4) play a significant role in the development of prenatal brain and the following stages. The study aimed to evaluate the effect of hypothyroidism on the amount of expression of NT4, NT3, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in brain of one-day rat neonates with hypothyroidism.Materials and Methods: In total, 25 mature mice of Albino NMRI race were selected after mating, divided into three group, control, as well as low-dose and high-dose intervention groups. Samples of the control group received pure water during pregnancy, whereas subjects of the intervention group with low and high doses of the medication were administered with 20 mg and 100 mg methimazole powder (dissolved in 100 cc water), respectively. After child delivery, blood samples were obtained from mother mice to determine the level of T3 and T4 in blood serum. Following that, the brain of one-day mice were removed by surgery and assessed to determine the amount of expression of NT4, NT3, NGF and BDNF using the complete kit of RT-PCR.Results: Levels of T4 and T3 in the control group were 28 ug/dl and 1.59 ug/dl, respectively. In the low-dose intervention group, the amounts of the mentioned hormones were 8 ug/dl and 0.85 ug/dl, significantly, indicating a significant reduction in the expression of NT4, NT3, NGF and BDNF genes, compared to the control group. Moreover, T4 and T3 were 6 ug/dl and 0.79 ug/dl in the high-dose group, respectively, conveying a significant decrease in the expression of NT4, NT3, NGF and BDNF genes, compared to the control group (P<0.05).

scholarly journals CD8+ T Cells Mediate Recovery andImmunopathology in West Nile VirusEncephalitis

2003 ◽  
Vol 77 (24) ◽  
pp. 13323-13334 ◽  
Author(s):  
Yang Wang ◽  
Mario Lobigs ◽  
Eva Lee ◽  
Arno Müllbacher
Keyword(s):  
T Cells ◽  
Dose Group ◽  
Low Dose ◽  
Neuronal Degeneration ◽  
High Dose ◽  
West Nile ◽  
Activation Markers ◽  
High Doses ◽  
The Brain ◽  
Deficient Mice

ABSTRACT C57BL/6J mice infected intravenously with the Sarafend strain of West Nile virus (WNV) develop a characteristic central nervous system (CNS) disease, including an acute inflammatory reaction. Dose response studies indicate two distinct kinetics of mortality. At high doses of infection (108 PFU), direct infection of the brain occurred within 24 h, resulting in 100% mortality with a 6-day mean survival time (MST), and there was minimal destruction of neural tissue. A low dose (103 PFU) of infection resulted in 27% mortality (MST, 11 days), and virus could be detected in the CNS 7 days postinfection (p.i.). Virus was present in the hypogastric lymph nodes and spleens at days 4 to 7 p.i. Histology of the brains revealed neuronal degeneration and inflammation within leptomeninges and brain parenchyma. Inflammatory cell infiltration was detectable in brains from day 4 p.i. onward in the high-dose group and from day 7 p.i. in the low-dose group, with the severity of infiltration increasing over time. The cellular infiltrates in brain consisted predominantly of CD8+, but not CD4+, T cells. CD8+ T cells in the brain and the spleen expressed the activation markers CD69 early and expressed CD25 at later time points. CD8+ T-cell-deficient mice infected with 103 PFU of WNV showed increased mortalities but prolonged MST and early infection of the CNS compared to wild-type mice. Using high doses of virus in CD8-deficient mice leads to increased survival. These results provide evidence that CD8+ T cells are involved in both recovery and immunopathology in WNV infection.

scholarly journals Toll-Like Receptor Signaling in Airborne Burkholderia thailandensis Infection

2009 ◽  
Vol 77 (12) ◽  
pp. 5612-5622 ◽  
Author(s):  
T. Eoin West ◽  
Thomas R. Hawn ◽  
Shawn J. Skerrett
Keyword(s):  
Low Dose ◽  
Inflammatory Responses ◽  
High Dose ◽  
Tlr Signaling ◽  
Necrosis Factor Alpha ◽  
Airborne Infection ◽  
Essential Components ◽  
High Doses

ABSTRACT Melioidosis is a tropical disease endemic in southeast Asia and northern Australia caused by the gram-negative soil saprophyte Burkholderia pseudomallei. Although infection is often systemic, the lung is frequently involved. B. thailandensis is a closely related organism that at high doses causes lethal pneumonia in mice. We examined the role of Toll-like receptors (TLRs), essential components of innate immunity, in vitro and in vivo during murine B. thailandensis pneumonia. TLR2, TLR4, and TLR5 mediate NF-κB activation by B. thailandensis in transfected HEK293 or CHO cells. In macrophages, TLR4 and the adaptor molecule MyD88, but not TLR2 or TLR5, are required for tumor necrosis factor alpha production induced by B. thailandensis. In low-dose airborne infection, TLR4 is needed for early, but not late, bacterial containment, and MyD88 is essential for control of infection and host survival. TLR2 and TLR5 are not necessary to contain low-dose infection. In high-dose airborne infection, TLR2 deficiency confers a slight survival advantage. Lung and systemic inflammatory responses are induced by low-dose inhaled B. thailandensis independently of individual TLRs or MyD88. These findings suggest that redundancy in TLR signaling or other MyD88-dependent pathways may be important in pneumonic B. thailandensis infection but that MyD88-independent mechanisms of inflammation are also activated. TLR signaling in B. thailandensis infection is substantially comparable to signaling induced by virulent B. pseudomallei. These studies provide additional insights into the host-pathogen interaction in pneumonic Burkholderia infection.

scholarly journals Validation of Pharmacological Protocols for Targeted Inhibition of Canalicular MRP2 Activity in Hepatocytes Using [99mTc]mebrofenin Imaging in Rats

Pharmaceutics ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 486
Author(s):  
Solène Marie ◽  
Irene Hernández-Lozano ◽  
Louise Breuil ◽  
Wadad Saba ◽  
Anthony Novell ◽  
...  
Keyword(s):  
Blood Flow ◽  
Biliary Excretion ◽  
Low Dose ◽  
Organic Anion ◽  
Liver Blood Flow ◽  
High Dose ◽  
Liver Uptake ◽  
Targeted Inhibition ◽  
Substrate Inhibitor

The multidrug resistance-associated protein 2 (MRP2) mediates the biliary excretion of drugs and metabolites. [99mTc]mebrofenin may be employed as a probe for hepatic MRP2 activity because its biliary excretion is predominantly mediated by this transporter. As the liver uptake of [99mTc]mebrofenin depends on organic anion-transporting polypeptide (OATP) activity, a safe protocol for targeted inhibition of hepatic MRP2 is needed to study the intrinsic role of each transporter system. Diltiazem (DTZ) and cyclosporin A (CsA) were first confirmed to be potent MRP2 inhibitors in vitro. Dynamic acquisitions were performed in rats (n = 5–6 per group) to assess the kinetics of [99mTc]mebrofenin in the liver, intestine and heart-blood pool after increasing doses of inhibitors. Their impact on hepatic blood flow was assessed using Doppler ultrasound (n = 4). DTZ (s.c., 10 mg/kg) and low-dose CsA (i.v., 0.01 mg/kg) selectively decreased the transfer of [99mTc]mebrofenin from the liver to the bile (k3). Higher doses of DTZ and CsA did not further decrease k3 but dose-dependently decreased the uptake (k1) and backflux (k2) rate constants between blood and liver. High dose of DTZ (i.v., 3 mg/kg) but not CsA (i.v., 5 mg/kg) significantly decreased the blood flow in the portal vein and hepatic artery. Targeted pharmacological inhibition of hepatic MRP2 activity can be achieved in vivo without impacting OATP activity and liver blood flow. Clinical studies are warranted to validate [99mTc]mebrofenin in combination with low-dose CsA as a novel substrate/inhibitor pair to untangle the role of OATP and MRP2 activity in liver diseases.

scholarly journals M211. NEUROPROTECTIVE EFFECT OF SHI-ZHEN-AN-SHEN-TANG, A CHINESE HERB FORMULA ON MICE EXPOSED TO CUPRIZONE

2020 ◽  
Vol 46 (Supplement_1) ◽  
pp. S216-S217
Author(s):  
Chao Ma ◽  
Yan Wu ◽  
Pei Chen ◽  
Yuan Jia ◽  
Dongqing Yin ◽  
...  
Keyword(s):  
Low Dose ◽  
Neuroprotective Effect ◽  
Chinese Herb ◽  
Large Body ◽  
High Dose ◽  
Neuregulin 1 ◽  
The Brain ◽  
Different Doses ◽  
Medium Dose

Abstract Background Our previous study indicated a therapeutic effect of Shi-Zhen-An-Shen-Tang (SZAST), a Chinese herb formula, on schizophrenia, but the related mechanism is unknown(citation). A large body of evidence suggests the important role of white matter of the brain in the pathophysiology of schizophrenia. This study was designed to evaluate the effect of SZAST on schizophrenia with demyelinated mice. Methods Male C57BL/6 mice were given mixed cuprizone (CPZ, a copper chelator, 0.2 %, w/w) rodent chow for six successive weeks to induce demyelination. During the last two weeks, mice were given an oral gavage of saline, or SZAST of three different doses (a low dose of 5.5g·kg-1·d-1, a medium dose of 8.24g·kg-1·d-1, or a high dose of 10.98 g·kg-1·d-1), or quetiapine, respectively. Behavioral tests were conducted after the last treatment. Meanwhile, the expression of myelin basic protein (MBP) and neuregulin-1(NRG1) in the brain was tested by immunohistochemistry staining or Western Blot. Results Mice exposed to CPZ for six weeks showed obvious schizophrenia-like behaviors, including lower nest-building activity, sensory gating activity, and higher locomotor activity. CPZ-fed mice also displayed a lower myelin density in the corpus callosum, hippocampus, and cerebral cortex and a reduction of MBP and NRG1 protein in the hippocampus compared with controls. Both quetiapine and SZAST significantly alleviated the abnormal schizophrenia-like behaviors and the impairment of myelin sheath in CPZ-fed mice, however, SZAST with medium dose showed better neuroprotective effect than the low dose or the high dose of SZAST. Furthermore, the expression of NRG1protein in the hippocampus was slightly, but not significantly increased in all SZAST-treated and quetiapine-treated groups. Discussion These results indicate that the neuroprotective effect of SZAST in demyelinated mice might partially relate to remyelination in the hippocampus in CPZ-fed mice.

Role of High-Dose Intravenous Frusemide Therapy in the Management of Chronic Renal Failure

1975 ◽  
Vol 3 (4) ◽  
pp. 245-250
Author(s):  
Mam Chandra ◽  
M K Mitra ◽  
N N Gupta
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Side Effects ◽  
Treated Group ◽  
Fixed Dose ◽  
High Dose ◽  
Dose Regime ◽  
Diuretic Response ◽  
High Doses

The results of using high doses of intravenous frusemide in the management of 28 patients suffering from chronic renal failure are presented. The results are compared with those obtained from 14 patients also suffering from chronic renal failure, who received identical ‘conservative management’ but were not treated with diuretics. Large doses of intravenous frusemide produced a satisfactory diuretic response in a higher percentage of treated patients (71%) compared with controls (36%). It was also observed that in the treated group of patients a significant diuretic response could be obtained in patients with a creatinine clearance below 4 ml per minute. The study also demonstrated that in the group of patients receiving frusemide the response was better in those who were given a progressive-dose regime; 88% of patients improved with this regime compared with 68% of patients who were treated with a fixed dose of frusemide. Transient deafness with tinnitus and vertigo were the only side-effects observed. However these effects were only seen in patients who received 1000 mg or more frusemide in one day, administered over a period of one to two hours. It is concluded that all patients suffering from chronic renal failure should be given a trial of large doses of intravenous frusemide therapy, along with other conventional measures, particularly where facilities for dialysis are not immediately available.

Effects of long-term continuous GnRH administration on the pituitary–gonadal axis in Eld's deer stags (Cervus eldi thamin)

1995 ◽  
Vol 73 (9) ◽  
pp. 1609-1619 ◽  
Author(s):  
S. L. Monfort ◽  
J. L. Brown ◽  
T. C. Wood ◽  
M. Bush ◽  
L. R. Williamson ◽  
...  
Keyword(s):  
Dose Group ◽  
Low Dose ◽  
High Dose ◽  
Fertile Period ◽  
Nonbreeding Season ◽  
Testosterone Secretion ◽  
High Doses ◽  
Seasonal Decline ◽  
Seasonally Breeding

Eld's deer stags (Cervus eldi thamin) (in groups of three) were continuously administered gonadotropin-releasing hormone (GnRH) in control, low, medium, or high doses (0, 20.1 ± 0.7, 83.3 ± 2.6, and 292.9 ± 4.9 ng∙kg−1∙d−1, respectively) via osmotic minipumps for ~80 d to investigate the potential for precociously reactivating the pituitary–testicular axis during the nonbreeding season. Secretory patterns of LH, FSH, and testosterone concentrations were qualitatively similar among treatments. However, in the low-dose group, basal LH and FSH concentrations were both increased (p < 0.05) and pituitary responsiveness to a superimposed GnRH challenge was augmented (p < 0.05) after 12 weeks of treatment compared with all other groups. Despite these endocrine changes, continuous low-dose GnRH administration was not effective for precociously inducing testicular activity in this seasonally breeding species. High-dose GnRH administration initially induced a transient increase in LH, FSH, and testosterone secretion and delayed, but did not prevent, the seasonal decline in spermatogenesis. After 6–12 weeks of high-dose GnRH administration, however, attenuated pituitary responsiveness appeared to delay the normal seasonal reactivation of the pituitary–gonadal axis. In conclusion, prolonged, continuous low-dose GnRH administration did not effectively translate into a precocious onset of testicular activity; therefore, this specific approach is unlikely to be useful for prolonging the fertile period in this seasonally breeding species.

Pooling of Laying Hen Environmental Swabs and Efficacy of Salmonella Detection

2020 ◽  
Vol 83 (6) ◽  
pp. 943-950
Author(s):  
DEANA R. JONES ◽  
RICHARD K. GAST ◽  
PRAFULLA REGMI ◽  
GARRETT E. WARD ◽  
KENNETH E. ANDERSON ◽  
...  
Keyword(s):  
Salmonella Typhimurium ◽  
Salmonella Enteritidis ◽  
Low Dose ◽  
High Dose ◽  
Environmental Testing ◽  
Naturally Occurring ◽  
Rate Of Recovery ◽  
High Doses ◽  
The U.S ◽  
Salmonella Heidelberg

ABSTRACT Environmental testing for Salmonella Enteritidis is required for U.S. shell egg producers with ≥3,000 hens on a farm. The egg producer assumes all costs for the mandatory testing. According to the U.S. Food and Drug Administration (FDA) Egg Rule, either manure scraper or drag swabs can be collected according to published guidelines and requirements. The present study was undertaken to determine the efficacy of Salmonella detection with one-, two-, and four-swab pools of either manure scraper or drag swabs. Resistant isolates of Salmonella serovars Enteritidis (1,000 ppm of streptomycin), Heidelberg (200 ppm of nalidixic acid [NA]), Typhimurium (200 ppm of NA), and Kentucky (200 ppm of NA) were utilized. Low (approximately 8.4 CFU) and high (approximately 84 CFU) levels of inocula were introduced onto a single swab within a pool. Single flocks from each conventional cage (manure scraper swabs) and cage-free barn (drag swabs) were monitored throughout the study at the ages required under the FDA Egg Rule. The highest and most consistent recovery of inoculum was found in single swab samples. For low dose inocula, recovery of isolates was low from single manure scraper swabs (57.9 to 29.2%) and decreased as more swabs were added to the pool. Recovery of isolates from manure scraper swabs was higher for high dose inocula, although Salmonella Heidelberg was outcompeted by the naturally occurring flora and had the lowest rate of recovery among the isolates tested. One- and two-swab pools of drag swabs had similar rates of recovery at both low and high doses for Salmonella Enteritidis, Salmonella Heidelberg, and Salmonella Typhimurium. When Salmonella Enteritidis and Salmonella Kentucky were combined in an inoculum, Salmonella Enteritidis was recovered at a much higher rate than was Salmonella Kentucky for all types of swabs and doses of inocula. Pooling of two drag swabs allowed for similar detection of low and high dose Salmonella, but the pooling of manure scraper swabs decreased detection of low dose Salmonella. HIGHLIGHTS

Extravasation Injury Associated with Low-Dose Dopamine

1998 ◽  
Vol 32 (5) ◽  
pp. 545-548 ◽  
Author(s):  
Julie L Chen ◽  
Marianne O'Shea
Keyword(s):  
Low Dose ◽  
Tissue Injury ◽  
Case Reports ◽  
Blood Perfusion ◽  
High Dose ◽  
Dopamine Infusion ◽  
Tissue Ischemia ◽  
Large Vein ◽  
High Concentrations ◽  
High Doses

OBJECTIVE: To describe the occurrence of extravasation in two patients receiving low-dose dopamine infusions. CASE SUMMARY: Intravenous dopamine was infused peripherally (in the antecubital fossa) to two patients in the cardiac intensive care unit in an attempt to enhance renal blood perfusion and urine output. Dopamine extravasation occurred in both patients while the low dose (<3 μg/kg/min) was infused. Significant local tissue injury was observed in both patients. DISCUSSION: Dopamine infusion can cause tissue ischemia or necrosis secondary to vasospasm and extravasation. Most of the case reports in the literature have occurred when relatively high doses of dopamine were infused. Only one reported extravasation-induced injury with low-dose dopamine. Although low-dose dopamine has a vasodilatory effect in selected tissues, high concentrations achieved locally as a result of extravasation can still cause severe vasoconstriction and ischemic tissue injury. CONCLUSIONS: Low-dose dopamine therapy should be administered with similar precautions as high-dose dopamine. A central intravenous access should be placed for dopamine infusion whenever possible. If this approach is not feasible, dopamine should be infused only peripherally through a long intravenous catheter into a large vein. A 5-cm angiocatheter that is 20 gauge or larger is recommended for peripheral dopamine infusion in our institution. The infusion site should be inspected frequently for early detection of extravasation, and changed to a central or a peripherally inserted central catheter as soon as possible, especially in patients at high risk for extravasation.

Biochemical modulation of fluorouracil with leucovorin: confirmatory evidence of improved therapeutic efficacy in advanced colorectal cancer.

1991 ◽  
Vol 9 (11) ◽  
pp. 1967-1972 ◽  
Author(s):  
M A Poon ◽  
M J O'Connell ◽  
H S Wieand ◽  
J E Krook ◽  
J B Gerstner ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Survival Benefit ◽  
Low Dose ◽  
Advanced Colorectal Cancer ◽  
Single Agent ◽  
Biochemical Modulation ◽  
High Dose ◽  
Significant Survival ◽  
High Doses ◽  
Administration Schedules

In a previous study (J Clin Oncol 7:1407-1417, 1989), we identified two dosage administration schedules of fluorouracil (5FU) combined with leucovorin that were superior to single-agent 5FU for the treatment of advanced colorectal cancer. In this same study, a regimen of 5FU plus high-dose methotrexate (MTX) demonstrated a suggestive advantage over 5FU alone. To permit a more definitive comparison, we have extended our evaluation of these three regimens to involve an additional 259 patients. In all, 457 patients with advanced colorectal cancer were randomly assigned to one of the following regimens: 5FU plus low-dose leucovorin, 5FU plus high-dose leucovorin, or 5FU plus high-dose MTX with leucovorin rescue. We have found that each of the 5FU/leucovorin regimens demonstrates a significant (P less than or equal to .01) advantage over 5FU plus high-dose MTX for objective tumor response and interval to tumor progression. Moreover, 5FU plus low-dose leucovorin confers a significant survival benefit (P less than or equal to .01) compared with 5FU plus high-dose MTX. The 5FU plus high-dose leucovorin regimen shows a survival benefit only in unadjusted analyses (P = .04), but this difference is not significant when adjusted for imbalances in prognostic variables (P = .44). Evaluation of the two 5FU/leucovorin regimens rules out a 10% decrease in death rate for the high-dose leucovorin regimen compared with the low-dose leucovorin regimen (P less than .05). The regimen of 5FU plus low-dose leucovorin has now been shown to offer a statistically significant survival advantage versus 5FU alone and versus 5FU plus high-dose MTX, a regimen that had shown promise in earlier trials. These data confirm the efficacy of leucovorin combined with 5FU in patients with advanced colorectal cancer and establish that it is not necessary to use high doses of leucovorin to achieve these results.

Sign in / Sign up

Export Citation Format

Share Document