Is the natural UV zone important for successful captive propagation of the Panther Chameleon (
            Furcifer pardalis
            ); are different UVB irradiance exposures that generate a similar dose equally successful?

ABSTRACT An extract of human urine, which was previously shown to stimulate aldosterone production by rat adrenal sections, was further purified. Evidence was obtained that its aldosterone-stimulating effect was due to the presence of ammonium ions. Addition of ammonium chloride and of urine extract to the incubation medium caused identical increases in aldosterone production in vitro. In addition to ammonium ions, rubidium and caesium ions also stimulated aldosterone production up to 250% that of control values without a significant effect on corticosterone production. Similar dose-response curves were obtained when increasing concentrations of potassium, ammonium, rubidium and caesium ions were tested. Aldosterone production was maximal at concentrations of 7 mval/1 and was significantly lower at higher concentrations. When ammonium chloride and ACTH were simultaneously added to the incubation medium, the production of aldosterone and of corticosterone was lower than with ACTH alone. On the other hand, the stimulating activity on aldosterone and corticosterone production by »TPN« (NADP) and glucose-6-phosphate was enhanced by the simultaneous addition of ammonium chloride.

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Polymeric Micelles for the Enhanced Deposition of Hydrophobic Drugs into Ocular Tissues, without Plasma Exposure

Pharmaceutics ◽

10.3390/pharmaceutics13050744 ◽

2021 ◽

Vol 13 (5) ◽

pp. 744

Author(s):

Ijeoma F. Uchegbu ◽

Jan Breznikar ◽

Alessandra Zaffalon ◽

Uche Odunze ◽

Andreas G. Schätzlein

Keyword(s):

Polymeric Micelles ◽

Rabbit Model ◽

Penetration Enhancer ◽

Hydrophobic Drugs ◽

Ocular Tissues ◽

Ocular Penetration ◽

Self Assembling ◽

Similar Dose ◽

Oil In Water ◽

The Stability

Commercial topical ocular formulations for hydrophobic actives rely on the use of suspensions or oil in water emulsions and neither of these formulation modalities adequately promote drug penetration into ocular tissues. Using the ocular relevant hydrophobic drug, cyclosporine A (CsA), a non-irritant ocular penetration enhancer is showcased, which may be used for the formulation of hydrophobic actives. The activity of this penetration enhancer is demonstrated in a healthy rabbit model. The Molecular Envelope Technology (MET) polymer (N-palmitoyl-N-monomethyl-N,N-dimethyl-N,N,N-trimethyl-6-O-glycolchitosan), a self-assembling, micelle-forming polymer, was used to formulate CsA into sterile filtered nanoparticulate eye drop formulations and the stability of the formulation tested. Healthy rabbits were dosed with a single dose of a MET–CsA (NM133) 0.05% formulation and ocular tissues analyzed. Optically clear NM133 formulations were prepared containing between 0.01–0.1% w/v CsA and 0.375–0.75% w/v MET polymer. NM133 0.01%, NM133 0.02% and NM133 0.05% were stable for 28 days when stored at refrigeration temperature (5–6 °C) and room temperature (16–23 °C), but there was evidence of evaporation of the formulation at 40 °C. There was no change in drug content when NM133 0.05% was stored for 387 days at 4 °C. On topical dosing to rabbits, corneal, conjunctival and scleral AUC0–24 levels were 25,780 ng.h g−1, 12,046 ng.h g−1 and 5879 ng.h g−1, respectively, with NM133 0.05%. Meanwhile, a similar dose of Restasis 0.05% yielded lower values of 4726 ng.h/g, 4813 ng.h/g and 1729 ng.h/g for the drug corneal, conjunctival and scleral levels, respectively. NM133 thus delivered up to five times more CsA to the ocular surface tissues when compared to Restasis. The MET polymer was non-irritant up to a concentration of 4% w/v. The MET polymer is a non-irritant ocular penetration enhancer that may be used to deliver hydrophobic drugs in optically clear topical ocular formulations.

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Effect of acetylcholine infusion on adrenal vasculature and catecholamine secretion

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1993.265.3.h966 ◽

1993 ◽

Vol 265 (3) ◽

pp. H966-H972 ◽

Cited By ~ 1

Author(s):

J. R. Tobin ◽

M. J. Breslow ◽

R. J. Traystman

Keyword(s):

Blood Flow ◽

Muscarinic Receptor ◽

Cholinergic Receptor ◽

Catecholamine Secretion ◽

Receptor Stimulation ◽

Similar Dose ◽

Adrenal Vasculature ◽

Higher Doses

To evaluate effects of cholinergic receptor stimulation on regional adrenal blood flow (Q, radiolabeled microspheres) and catecholamine secretion, acetylcholine (ACh) was infused into pentobarbital-anesthetized, ventilated dogs. Unilateral adrenal denervation and placement of lumboadrenal catheters preceded intra-aortic infusion of 1) ACh alone (n = 6), 2) ACh plus hexamethonium (Hex) 20 mg/kg (n = 6), or 3) ACh plus atropine (Atr) (0.5 mg/kg) and Hex. ACh alone and in combination with Hex elicited similar dose-related (2, 20, and 100 mumol/min) increases in catecholamine secretion (181 +/- 61 to 1,055 +/- 229, 31,644 +/- 9,411, and 179,181 +/- 69,659 ng.min-1 x g medulla-1), whereas Hex and Atr together inhibited ACh-induced secretion by 95%. ACh caused marked medullary vasodilation (0.71 +/- 0.05 to 0.14 +/- 0.03 mmHg.ml-1 x min.100 g) in all three groups. To determine whether medullary vasodilation was due to incomplete muscarinic blockade, Hex-pretreated animals (n = 4) received ACh (100 mumol/min) and three increasing doses of Atr (0.5, 5, and 25 mg/kg). Catecholamine secretion was inhibited by all doses of Atr; however, vasodilation was blocked only by the two higher doses of Atr. These data suggest possible different mechanisms of muscarinic receptor-mediated catecholamine secretion and vasodilation.

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Restoration of Susceptibility of Intracellular Methicillin-Resistant Staphylococcus aureus to β-Lactams: Comparison of Strains, Cells, and Antibiotics

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00123-08 ◽

2008 ◽

Vol 52 (8) ◽

pp. 2797-2805 ◽

Cited By ~ 17

Author(s):

Sandrine Lemaire ◽

Aurélie Olivier ◽

Françoise Van Bambeke ◽

Paul M. Tulkens ◽

Peter C. Appelbaum ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Dose Response ◽

Intermediate Phenotype ◽

Maximal Effect ◽

Response Curves ◽

Methicillin Resistant ◽

Complete Restoration ◽

Similar Dose ◽

Dose Response Curves ◽

Mrsa Strains

ABSTRACT Staphylococcus aureus invades eukaryotic cells. When methicillin-resistant S. aureus (MRSA) ATCC 33591 is phagocytized by human THP-1 macrophages, complete restoration of susceptibility to cloxacillin and meropenem is shown and the strain becomes indistinguishable from MSSA ATCC 25923 due to the acid pH prevailing in phagolysosomes (S. Lemaire et al., Antimicrob. Agents Chemother. 51:1627-1632, 2007). We examined whether this observation can be extended to (i) strains of current clinical and epidemiological interest (three hospital-acquired MRSA [HA-MRSA] strains, two community-acquired MRSA [CA-MRSA] strains, two HA-MRSA strains with the vancomycin-intermediate phenotype, one HA-MRSA strain with the vancomycin-resistant phenotype, and one animal [porcine] MRSA strain), (ii) activated THP-1 cells and nonprofessional phagocytes (keratinocytes, Calu-3 bronchial epithelial cells), and (iii) other β-lactams (imipenem, oxacillin, cefuroxime, cefepime). All strains showed (i) a marked reduction in MICs in broth at pH 5.5 compared with the MIC at pH 7.4 and (ii) sigmoidal dose-response curves with cloxacillin (0.01× to 100× MIC, 24 h of incubation) after phagocytosis by THP-1 macrophages that were indistinguishable from each other and from the dose-response curve for methicillin-susceptible S. aureus (MSSA) ATCC 25923 (relative potency [50% effect], 6.09× MIC [95% confidence interval {CI}, 4.50 to 8.25]; relative efficacy [change in bacterial counts over the original inoculum for an infinitely large cloxacillin concentration, or maximal effect], −0.69 log CFU [95% CI, −0.79 to −0.58]). Similar dose-response curves for cloxacillin were also observed with MSSA ATCC 25923 and MRSA ATCC 33591 after phagocytosis by activated THP-1 macrophages, keratinocytes, and Calu-3 cells. By contrast, there was a lower level of restoration of susceptibility of MRSA ATCC 33591 to cefuroxime and cefepime after phagocytosis by THP-1 macrophages, even when the data were normalized for differences in MICs. We conclude that the restoration of MRSA susceptibility to β-lactams after phagocytosis is independent of the strain and the types of cells but varies between β-lactams.

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Volatile Anaesthetic Depression of the Carotid Body Chemoreflex-Mediated Ventilatory Response to Hypoxia: Directions for Future Research

Scientifica ◽

10.1155/2014/394270 ◽

2014 ◽

Vol 2014 ◽

pp. 1-15 ◽

Cited By ~ 2

Author(s):

J. J. Pandit

Keyword(s):

Quantitative Analysis ◽

Carotid Body ◽

Meta Analysis ◽

Future Research ◽

Inclusion Criteria ◽

Molecular Processes ◽

Similar Dose ◽

Hypercapnic Response ◽

Ventilatory Response To Hypoxia ◽

Body Response

In assessing whether volatile anaesthetics directly depress the carotid body response to hypoxia it is necessary to combine in meta-analysis studies of when it is “functionally isolated” (e.g., recordings are made from its afferent nerve). Key articles were retrieved (full papers in English) and subjected to quantitative analysis to yield an aggregate estimate of effect. Results from articles that did not use such methodology were assessed separately from this quantitative approach, to see what could be learned also from a nonquantitative overview. Just 7 articles met the inclusion criteria for hypoxia and just 6 articles for hypercapnia. Within these articles, the anaesthetic (mean dose 0.75, standard deviation (SD) 0.40 minimum alveolar concentration, MAC) statistically significantly depressed carotid body hypoxic response by 24% (P=0.041), but a similar dose (mean 0.81 (0.42) MAC) did not affect the hypercapnic response. The articles not included in the quantitative analysis (31 articles), assessed qualitatively, also indicated that anaesthetics depress carotid body function. This conclusion helps direct future research on the anaesthetic effects on putative cellular/molecular processes that underlie the transduction of hypoxia in the carotid body.

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The role of Ca2+ in the protoveratrine-induced release of γ-aminobutyrate from rat brain slices

Biochemical Journal ◽

10.1042/bj1900333 ◽

1980 ◽

Vol 190 (2) ◽

pp. 333-339 ◽

Cited By ~ 19

Author(s):

M C W Minchin

Keyword(s):

Cerebral Cortex ◽

Rat Brain ◽

Dose Response ◽

Transmitter Release ◽

Response Curve ◽

Brain Slices ◽

Veratrum Alkaloids ◽

Similar Dose ◽

22Na Uptake

1. Protoveratrine A increased the release of gamma-amino[3H]butyrate from small slices of rat cerebral cortex. This effect increased with increasing protoveratrine concentration, reaching a maximum at 100 microM. 2. Removal of Ca2+ from the superfusing medium did not change the increase in release due to 10 microM-protoveratrine; however, the Ca2+ antagonists, compound D-600, La3+, Mn2+, Mg2+ and also high Ca2+ concentration inhibited the effect of the alkaloid, as did procaine. 3. Protoveratrine A increased the uptake of 22Na+ into the slices with a similar dose-response curve to that found for gamma-aminobutyrate release. For the most part, the substances that inhibited protoveratrine-stimulated gamma-aminobutyrate release also inhibited 22Na+ uptake, although the correlation was not perfect. 4. Although extracellular Ca2+ is not required for protoveratrine-induced gamma-aminobutyrate release, an increase in Na+ influx that is susceptible to inhibition by some Ca2+ antagonists does appear to be associated with this phenomenon. However, the possibility remains that changes in the free intracellular Ca2+ concentration may be important for transmitter release induced by depolarizing veratrum alkaloids.

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Letters to the Editor

PEDIATRICS ◽

10.1542/peds.67.3.445a ◽

1981 ◽

Vol 67 (3) ◽

pp. 445-445

Author(s):

Gilberto Pereira

Keyword(s):

Fatty Acids ◽

Free Fatty Acids ◽

Newborn Infants ◽

Letters To The Editor ◽

Similar Dose ◽

The One

I think it is important to stress that the dose of Intralipid used in the study in the amount of 1 gm/kg over a four-hour infusion was selected for two major reasons. The first reason was that the dose was the one used by Andrew and others in the initial studies of Intralipid clearance in newborn infants. We wanted to compare the peak levels of free fatty acids and triglycerides in our patients following a similar dose given over a similar period of time.

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Phasic Genioglossus and Palatoglossus Muscle Activity during Recovery from Sevoflurane Anesthesia

Anesthesiology ◽

10.1097/aln.0b013e318295a27b ◽

2013 ◽

Vol 119 (3) ◽

pp. 562-568 ◽

Cited By ~ 2

Author(s):

Ilavajady Srinivasan ◽

Samuel Strantzas ◽

Mark W. Crawford

Keyword(s):

Muscle Activity ◽

Upper Airway ◽

Dependent Manner ◽

Sevoflurane Anesthesia ◽

Phasic Activity ◽

Similar Dose ◽

Inhalational Anesthetic ◽

Recovery From Anesthesia ◽

End Tidal ◽

Dose Dependent

Abstract Background: Inhalational anesthetic effects on upper airway muscle activity in children are largely unknown. The authors tested the hypothesis that phasic inspiratory genioglossus and palatoglossus activity increases during recovery from sevoflurane anesthesia in a dose-dependent manner in children. Methods: Sixteen children, aged 2.0 to 6.9 yr, scheduled for elective urological surgery were studied. Electromyogram recordings were acquired using intramuscular needle electrodes during spontaneous ventilation. After a 15-min period of equilibration, electromyogram activity was recorded over 30 s at each of three end-tidal concentrations, 1.5, 1.0, and 0.5 minimum alveolar concentration (MAC), administered in sequence. Results: Phasic genioglossus activity was noted in four children at 1.5 MAC, five at 1.0 MAC, and six children at 0.5 MAC sevoflurane. Phasic palatoglossus activity was noted in 4 children at 1.5 MAC, 6 at 1.0 MAC, and 10 children at 0.5 MAC sevoflurane. Both the proportion of children exhibiting phasic activity, and the magnitude of phasic activity increased during recovery from anesthesia. For the genioglossus, decreasing the depth of sevoflurane anesthesia from 1.5 to 1.0 MAC increased phasic activity by approximately 35% and a further decrease to 0.5 MAC more than doubled activity (median [range] at 1.5 and 0.5 MAC: 2.7 μV [0 to 4.0 μV] and 8.6 μV [3.2 to 17.6], respectively; P = 0.029). A similar dose-related increase was recorded at the palatoglossus (P = 0.0002). Conclusions: Genioglossus and palatoglossus activity increases during recovery from sevoflurane anesthesia in a dose-dependent manner over the clinical range of sevoflurane concentrations in children.

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