Innovative Aqueous Nanoemulsion Prepared by Phase Inversion Emulsification with Exceptional Homogeneity

Formulating low-solubility or low-permeability drugs is a challenge, particularly with the low administration volumes required in intranasal drug delivery. Nanoemulsions (NE) can solve both issues, but their production and physical stability can be challenging, particularly when a high proportion of lipids is necessary. Hence, the aim of the present work was to develop a NE with good solubilization capacity for lipophilic drugs like simvastatin and able to promote the absorption of drugs with low permeability like fosphenytoin. Compositions with high proportion of two lipids were screened and characterized. Surprisingly, one of the compositions did not require high energy methods for high droplet size homogeneity. To better understand formulation factors important for this feature, several related compositions were evaluated, and their relative cytotoxicity was screened. Optimized compositions contained a high proportion of propylene glycol monocaprylate NF, formed very homogenous NE using a low-energy phase inversion method, solubilized simvastatin at high drug strength, and promoted a faster intranasal absorption of the hydrophilic prodrug fosphenytoin. Hence, a new highly homogeneous NE obtained by a simple low-energy method was successfully developed, which is a potential alternative for industrial application for the solubilization and protection of lipophilic actives, as well as (co-)administration of hydrophilic molecules.

Role of lysosomes on human ulcerogenic gastropathies. Effect of zinc ion on the lysosomal stability

Numerous conditions are involved in the equilibrium between protective and aggressive factors for gastric mucosa injuring. Among them the lysosomal membrane stability plays a very important role in the inflammatory process. Zinc ion is a well-known lysosomal membrane stabilizer. When given orally to animals or even to humans it protects gastric mucosa against erosive lesions induced by a variety of experimental conditions. Compared with the control group (8.45 +/- 1.49 mU/mg) the lysosomes isolated from samples of gastric mucosa obtained from patients suffering of erosive gastropathies, showed a great liability on their membranes (18.37 +/- 4.52 mU/mg). When these patients were treated orally with zinc sulfate (100 mg of zinc element, twice a day, for two weeks) the lysosomes isolated from their gastric mucosa showed a strong reduction on enzymatic activity (5.49 +/- 1.02 mU/mg), probably due to increasing on the membrane stability. Based on these experimental findings we propose the use of zinc ion as an important adjuvant in treatment of erosive gastropathies.

The effect of magnesium supplementation in increasing doses on the control of type 2 diabetes

OBJECTIVE

Hypomagnesemia occurs in 25-38% of patients with type 2 diabetes. Several studies have suggested an association between magnesium (Mg) depletion and insulin resistance and/or reduction of insulin secretion in these cases. Our purpose was to evaluate if Mg supplementation (as magnesium oxide [MgO]) would improve metabolic control in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We studied 128 patients with type 2 diabetes (32 men, 96 women, aged 30-69 years), treated by diet or diet plus oral antidiabetic drugs, in the Bahia Federal University Hospital, Brazil. Patients at risk for hypomagnesemia or with reduced renal function were excluded. This study was a clinical randomized double-blind placebo-controlled trial. Patients received either placebo, 20.7 mmol MgO, or 41.4 mmol MgO daily (elementary Mg) for 30 days. Mg concentrations were measured in plasma, in mononuclear cells, and in 24-h urine samples. Fasting blood glucose, HbA1, and fructosamine were used as parameters of metabolic control.

RESULTS

Of the patients, 47.7% had low plasma Mg, and 31.1% had low intramononuclear Mg levels. Intracellular Mg in patients with diabetes was significantly lower than in the normal population (62 blood donors; 1.4 +/- 0.6 vs. 1.7 +/- 0.6 micrograms/mg of total proteins). No correlation was found between plasma and intracellular Mg concentrations (r = -0.179; P = 0.15) or between Mg concentrations and glycemic control (r = -0.165; P = 0.12). Intracellular Mg levels were lower in patients with peripheral neuropathy than in those without (1.2 +/- 0.5 vs. 1.5 +/- 0.6 micrograms/mg). Similar findings were observed in patients with coronary disease (1.0 +/- 0.5 vs. 1.5 +/- 0.6 micrograms/mg). In the placebo and in the 20.7 mmol Mg groups, neither a change in plasma and intracellular levels nor an improvement in glycemic control were observed. Replacement with 41.4 mmol Mg tended to increase plasma, cellular, and urine Mg and caused a significant fall (4.1 +/- 0.8 to 3.8 +/- 0.7 mmol/l) in fructosamine (normal, 1.87-2.87 mmol/l).

CONCLUSIONS

Mg depletion is common in poorly controlled patients with type 2 diabetes, especially in those with neuropathy or coronary disease. More prolonged use of Mg in doses that are higher than usual is needed to establish its routine or selective administration in patients with type 2 diabetes to improve control or prevent chronic complications.

[Biochemistry of schistosomiasis mansoni: involvement of siderosomes in hepatic inflammatory processes]

The inflammatory processes that develop during the advanced stages of hepatic schistosomiasis mansoni have been related in this study to: (a) accumulation of siderosomes; (b) capacity of the ferrous/ferric ions to unleash the formation of free radicals; (c) peroxidation of membrane lipids and; (d) reduction of stability of the membranes of several components of the hepatic lysosomal compartment. The lysosomes isolated from the livers of infected mice by 100 cercariae, with 80 and 100 days of infection, were respectively 2.5 and almost 4 times weaker than the control ones isolated from livers of non-infected mice. The presence of a great quantity of siderosomes has been demonstrated by transmission electronic microscopy and X-ray spectrometry microanalysis.

[Biochemistry of schistosomiasis mansoni. VII. Lipid changes of lysosomal membranes during the initial phase of liver injury]

Aiming at investigating the changes on the lipidic constitution of hepatic lysosomal membranes at the initial phase of schistosomatic damage, mice have been infected with 30 cercarias and employed for essais in the 30th day of infection. The triacylglycerois decreased from 220 +/- 48 micrograms/mg of total proteins in the control mice, to 165 +/- 22 micrograms/mg in the infected ones. Similarly, the free cholesterol, also decreased from 539 +/- 80 to 396 +/- 54 micrograms/mg; the cholesterol esters from 270 +/- 35 to 216 +/- 36 micrograms/mg and the phosphatidylcholines from 44 +/- 5.7 to 31 +/- 4.9 micrograms/mg. The phosphatidylserines the phosphatidylethanolamines and the sphingomyelins increased, respectively from 58 +/- 9.7 to 60 +/- 8.5, from 72 +/- 7.8 to 111 +/- 15.7 and from 36 +/- 4.9 to 63 +/- 7.1 micrograms/mg. The free fatty acids showed no statistical significance on their variations. They varied from 1.7 +/- 0.25 microEq/g in the controls to 1.8 +/- 0.39 microEq/g in the infected animals. These results indicated that in the initial phase of hepatic schistosomiasis, before the formation of granulomas, important changes on the lipidic constitution of lysosomal membranes can be detected. It seems that they are provoked by the catabolic excreted by immature or adult worms of Schistosoma mansoni present in the portal vein system.

[Biochemistry of schistosomiasis mansoni. IV. Changes in the hepatic lysosome compartment in relation to the time of infection]

O Schistosoma mansoni e/ou seus ovos causam uma hepatopatia muito importante e com aspectos anátomo-clínicos bem característicos. Uma vez carregados pela corrente circulatória, os vermes podem ocluir ramos dicotômicos de maior calibre do sistema portal e, quando mortos produzem lesões às vezes extensas, primeiro necróticas, depois inflamatórias e, posteriormente cicatriciais, sempre circunscritas e não sistematizadas. Os ovos, além de penetrarem no's ramúsculos não dicotômicos da rede periductal, alcançam os ramos de distribuição ou até mesmo as vênulas aferentes, ocluin- do muitas delas e, como conseqüência, formam os granulomas intravasculares que podem levar a uma interrupção da corrente sangüínea portal a esse nível e alterações da circulação intralobular. A diminuição da taxa de oxigênio disponível e conseqüentemente o decréscimo do pH intra e extracelular são potentes labilizadores das membranas dos diversos componentes do compartimento lisossômico. A saída de hidrolases ácidas, proteínas catiônicas e hidrolases neutras, a partir desses orgãnulos, acarreta agressões tissulares muito importantes, com o desencadeamento e/ou manutenção dos processos inflamatórios típicos desta parasitose. Neste trabalho estudou-se as atividades lisossômicas ligadas às diversas fases da esquistossomose mansônica hepática. Os resultados indicaram que a integridade funcional dos complexos membranosos do compartimento lisossômico foi significativamente alterada, já a partir do segundo mês da infecção e que parece haver um estreito relacionamento entre o agravamento das lesões inflamatórias hepáticas com uma maior labilidade lisossômica.

Renal involvement in visceral leishmaniasis

In a prospective study of 50 patients with visceral leishmaniasis, laboratory abnormalities suggestive of renal involvement were not infrequent. Proteinuria and/or microscopic hematuria or pyuria were observed in 51% of such cases. Twenty-four hour urinary protein excretion was elevated in 57% of patients in all cases below 1g/24 hours. An abnormal acid-load test was demonstrated in 12 of 18 patients studied before therapy of the parasitic infection with N-methyl-glucamine. Of interest was the demonstration of tubulo-interstitial involvement in the renal histology of all seven patients studied; also, in five of seven patients there was a proliferative glomerulonephritis, usually mild, on histologic examination. In general, there was a tendency to subsidence of abnormal laboratory findings within one month after specific therapy. Renal involvement in visceral leishmaniasis was mild and seemed to revert with the cure of the leishmanial infection.

[Lysosomotropism and anti-inflammatory action of gold salts]

Gold salts have been widely used in the past 70 years in the treatment of various connective tissue diseases and more particularly in rheumatoid arthritis. However their mechanism of action remains poorly understood. Gold salts are transported in the blood linked with several serum proteins including immunoglobulins. Methods of analytical electron microscopy (Castaing probe) have shown that gold is actively concentrated in the lysosomes of various cell types, including the proximal tubular cells of the kidney and certain bone marrow cells. These data, together with those provided by biochemical techniques, suggest that sodium aurothiopropanol sulfonate modifies the stability of lysosome membranes. In the present study it is shown that the stability of kidney lysosomes of treated rats was increased by 42.4 per cent after treatment for 3 days. This protective action was also seen when lysosomes were subjected to lysis by digitonin. The protective effect of gold salts on the lysosomal membrane may be explained by the formation of chemical complexes between gold and sulfhydryl groups present in the membrane, resulting in stable mercaptic bonds. These findings suggest that the increase in stability of lysosomal membranes plays a significant role in the anti-inflammatory action of gold salts.

[Biochemistry of schistosomiasis mansoni. V. - Mitochondrial activity in the livers and the kidneys of marmosets (Callithrix penicillata) infested with Schistosoma mansoni]

Foram estudadas mitocôndrias isoladas de fígados e rins de sagüis (Callitrix penicillata) infestados pela inoculação de 200 cercárias e entre 80 e 100 dias de infecção, nos aspectos relativos às suas atividades respiratórias endógenas, bem como frente ao succinato e ao alfa ceto glutarato de sódio. Cada experiência foi acompanhada de controle, usando-se mitocôndrias isoladas de fígados e rins de animais não infectados. As medidas das atividades respiratórias foram efetuadas polarograficamente e expressas em microlitros de oxigênio consumidos por miligrama de proteínas totais por minuto. Os resultados mostraram que as respirações endógenas das mitocôndrias isoladas dos animais infectados foram sempre maiores do que aquelas observadas nos controles. Detectou-se um estímulo para o fígado de 217% e para o rim de 84%. O succinato de sódio estimulou em 85% a respiração das mitocôndrias dos fígados dos animais controles, enquanto a inibiu de 39% nos infectados. Com referência aos rins, este mesmo substrato estimulou a referida respiração tanto nos controles quanto nos infectados, em 89% e 94% respectivamente. O alfa ceto glutarato estimulou as mitocôndrias hepáticas isoladas dos controles em 48% e as renais em 84%. Nos animais esquistossomóticos ou ele não modificou a capacidade respiratória mitocondrial como se observou para o rim, ou a inibiu de 58%, no caso do fígado. Os dados obtidos sugerem que o fígado sofre muito mais, em termos bioquímicos, com a esquistossomose mansônica do que os rins, pelo menos em nossas condições experimentais. As atividades do sistema enzimático succinato desidrogenase e do complexo alfa ceto glutarato desidrogenase permitiram identificar bioquimicamente, em nossos animais esquistossomóticos, vários graus de lesão celular, principalmente hepáticos, que vão desde os mais simples, decorrentes de modificações da físico-química dos sistemas de membranas, até os mais graves, tipo necrose.

[Stabilizing action of verapamil "in vivo" upon the membrane of heart lysosomes (author's transl)]

The effect of the verapamil upon the stability of the membranes of lysosomes isolated from rabbit hearts was studied by means of the acid phosphatase activity, the mapping enzyme of the cytoplasmic organelles. A dose of 2.5 mg of verapamil was injected endovenously in each animal. After homogenization of a sample taken from the lower end of the heart, the lysosomes were isolated by fractionated centrifugation and refrigerated at 2 degrees C. The lysosomal activity of non treated animals was 43.1 +/- 8.9x10(-1)mU/mg. The activity of lysosomes isolated from verapamil treated animals without previous treatment "in vitro" with digitonin was 8.7 +/- 1.6x10(-1)mU/mg and the activity of those with previous treatment of digitonin was 9.1 +/- 2.1x10(-1)mU/mg. The activity of lysosomes isolated from the control group and treated "in vitro" by digitonin was 193.9 +/- 40.5x10(-10)mU/mg. Consequently, the verapamil proved to have a strong capacity of protection of the lysosome membranes when "in vivo".

The effect of electrical stimulation upon the activity of brain glutamate decarboxilase "in vitro"

Using the cytoplasmic soluble fraction from rat brain as a source of glutamate decarboxilase, its enzymatic activity was induced by electrical stimulation and determined by gas release. Modified Warburg's flasks were used for such determination. The limits of frequency and the use of sinusoidal waves were based on normal cerebral rhythms. At low frequencies, GAD activity is markedly enhanced (1-10 Hz, 2v, 500 muA). Activation of the enzyme may be due to distortion of the tertiary structure promoting thus an increased coupling between the substrate and the enzyme complex.

Effect of acute experimental uremia on the stability of liver lysosomal membranes

Acute uremia was induced in male Swiss albino mice by complete urethral ligation and the animals were sacrificed 2, 4-6, 24, and 48 h after operation. Sham-opeated animals (without the urethral ligation) were similarly treated. The blood urea levels of animals with total urinary tract obstruction went up to 175 mg/100 ml at 4-6 h of urethral ligation and reached an average level of 827 mg/100 ml at 48 h, while the control group exhibited and average blood urea level of 37 mg/100 ml. Lysosomes obtained from livers of uremic mice sacrificed at different time intervals demonstrated a lability of the lysosomal membranes (as determined by the acid phosphatase activity in mU/mg) which was maximal at 4-6 h of urethral ligation, declining towards normal at 24 and 48 h, despite an increase in the animal's blood urea. In vitro studies exposing liver lysosomes to progressively higher urea concentrations (differences of as much as 100,000 times) did not reveal any effect of urea upon the stability of lysosomal membranes. The reason for the lability of lysosomal membranes in the uremic group was not apparent in the present study.

Modification of the Warburg's flask for the study of electric current effect upon the activity of enzymatic systems

Modifications of the Warburg's flask were suggested for the study of the electric current effect upon enzymatic systems under directly stimulation "in vitro" and "in vivo" conditions. The proposed modifications made on the Warburg's flask were basically constituted by the insertion of two platinum and mercury electrodes in the principal reservoir. In order to demonstrate the efficiency and viability of the suggested modification, one experience concerning the effect of the electric current upon the cerebral glutamate decarboxylase activity was shown. The apoenzyme substrate system was activated 1.81 times by the electrical stimulation in absence of the coenzyme. In a similar way the complete system, that is, the apoenzyme-coenzyme-substrate was also stimulated. The physical phenomena seem to be of importance for the understanding of the physiology and biochemistry of the nervous tissue.

The effect of acute uremia on liver mitochondrial activity

The effect of acute uremia on the liver mitochondrial activity was studied in Swiss albino mice subjected to complete urethral obstruction and sacrificed at different time intervals. The specific respiratory coefficient (measured as microliters of oxygen utilized per milligram of total proteins X 10(-1)) was similar in uremic and sham-operated control groups. The utilization of succinate as substrate was also similar in uremic and controls. There was a tendency for decreasing utilization of alpha-glutarate as substrate by the uremic group, particularly after 48 h of total urinary obstruction. There was no correlation between the retention of urea and the degree of mitochondrial respiratory inhibition.

[Topographic and intracellular distribution of monoamine and diamine oxydases in rat stomach]

Up to now, the activity of D.A.O. and M.A.O. in the gastric mucosa of rat stomach has not been yet detected. Employing a radioisotopic method, modified by us, it was possible to detect the activity of both enzymes in sufficient amount to study their topographic and intracellular localization. Topographically, the antral region showed the highest activity for the two enzymes, being the D.A.O. 20 times stronger than the M.A.O. The intracellular localization of M.A.O. seems to be in the lysosomes but the D.A.O. looks like to be homogeneously distributed, except in the mitochondrial fraction. The simple demonstration of gastric intracellular distribution of these enzymes in the rat stomach should stimulate further investigations to elucidate the metabolism of histamine and its enzymatic regulations.

[Lysosome-rich synaptosomal preparations from rat mesencephalus (author's transl)]

Subcellular fraction, enriched with synaptosomes, obtained from rat brain has been found contaminated by lysosomes, as evidenced by the high content of acid phosphatase, their biochemical marker.