Cosolvency of Dimethyl Isosorbide for Steroid Solubility

Dimethyl isosorbide (DMI), which is currently under investigation for its potential use as a pharmaceutical vehicle and drug permeation enhancer, is a water-miscible liquid with relatively low viscosity. The solubilization behavior of DMI as a cosolvent for nonpolar drugs was characterized via dielectric constant measurements of binary solvent systems containing DMI and either water, propylene glycol (PG), or polyethylene glycol (PEG). Evidence from the dielectric constant profiles and NMR studies suggest that DMI undergoes complexation with water and PG, but not with PEG, through hydrogen bonding interactions. The solvent complexation exhibited a major effect on the solubilities of prednisone, dexamethasone, and prednisolone in the mixed solvent systems. Maximum solubility of each drug was found to occur near a DMI/water or DMI/PG concentration ratio of 1:2. In the DMI–PEG mixed system, while there is no apparent interaction between DMI and PEG molecules, the solubility of prednisone was found to increase with decreasing dielectric constant.     

Preparation of controlled release anticancer agents. I: 5-Fluorouracil-ethyl cellulose microspheres

Microspheres of 5-fluorouracil have been prepared, using three grades of ethyl cellulose as wall forming materials, and utilizing a solvent evaporation technique under ambient conditions. An alcoholic solution of 5-fluorouracil and polymer was dispersed in liquid paraffin containing 33.3 per cent n-heptane. The effect of stirring rate, time of stirring, drug loading, and polymer grade on drug release in two different media were evaluated. The drug loaded particles were spherical in shape and had a diameter range of 25-200 mm and were suitable for incorporating into a gel base. Drug release studies in aqueous media, showed that acidic media provide a faster release rate than neutral media. The drug release study from an aqueous gel base preparation at pH 7.0 through a synthetic membrane was found to be promising for formulation of a gel-microsphere product for the treatment of skin lesions.     

Oxygenator exhaust capnography: a method of estimating arterial carbon dioxide tension during cardiopulmonary bypass.

An in vivo study was undertaken during hypothermic (28 degrees C) cardiopulmonary bypass to compare oxygenator exhaust capnography as a means of estimating arterial carbon dioxide tension (PaCO2) with bench blood gas analysis. A total of 123 pairs of measurements were made in 40 patients. Oxygenator exhaust capnographic measurements systematically underestimated PaCO2 measured by a bench blood gas analyzer. During the cooling and stable hypothermic phases of cardiopulmonary bypass, the relationship was reasonably accurate, but became far more variable during rewarming. Oxygenator exhaust capnography could be used as an inexpensive means of continuously monitoring PaCO2 during the cooling and stable hypothermic phases of cardiopulmonary bypass but should not be used during rewarming.     

Resistance to recombinant human erythropoietin due to aluminium overload and its reversal by low dose desferrioxamine therapy.

Seventeen severely anaemic and transfusion-dependent haemodialysis patients with a haemoglobin less than 7 g/dl were treated with recombinant human erythropoietin (r-Hu-EPO). Aluminium toxicity was diagnosed by a positive desferrioxamine (DFO) test and bone biopsy. Seven out of eight patients without aluminium toxicity responded to r-Hu-EPO therapy. Similarly all patients with aluminium toxicity (n = 4) but pre-treated with standard dose of DFO prior to r-Hu-EPO therapy responded but none of the patients with untreated aluminium toxicity (n = 5) responded to r-Hu-EPO therapy. In order to achieve adequate response in these patients, r-Hu-EPO and DFO had to be given in combination. The dose of desferrioxamine used to reverse r-Hu-EPO resistance was less and also used for a short time. We therefore confirm r-Hu-EPO resistance owing to aluminium overload and report its successful and safe reversal with low dose DFO therapy.     

Transjugular intrahepatic cavoportal shunt for Budd–Chiari syndrome

Budd–Chiari syndrome (BCS) is characterized by obstruction of the hepatic venous outflow tract. Therapeutic options for BCS are limited. We report a case of a 21-year-old woman with protein S and C deficiency with gross ascites. Treatment with transjugular intrahepatic portosystemic shunt (TIPS) was attempted, which revealed occluded hepatic veins, so transcaval TIPS was performed. No serious procedure-related complication occurred. After successful shunt creation, the patient's symptoms subsided and she was discharged and followed up for 6 months.     

Integrin alpha2beta1 affects mechano-transduction in slowly and rapidly adapting cutaneous mechanoreceptors in rat hairy skin

The role of a transmembrane protein, integrin alpha2beta1, to modulate the neural responses of cutaneous mechanoreceptors to mechanical indentation was examined using an isolated skin-nerve preparation in a rat model. Skin and its intact innervation were harvested from the medial thigh of the hindlimb and placed in a dish containing synthetic interstitial fluid. Using a standard teased nerve preparation, the neural responses of single slowly or rapidly adapting mechanoreceptors (SA or RA, respectively) were identified and the afferents categorized according to standard protocols (i.e. response to constant stimuli). The most sensitive spot of a mechanoreceptor's receptive field was identified and then stimulated using controlled compressive stress (constant or dynamic loads between threshold and saturation load for SAs and RAs, respectively). Loads were applied before, during, and after passive diffusion into the skin of a function-blocking anti-integrin alpha2 monoclonal antibody (FBmAb) or one of two types of control antibodies (immunoglobulin G or a FBmAb conjugated with a secondary antibody). The sensitivities of both SA and RA mechanoreceptors were profoundly reduced in the presence of the FBmAb, while not changing the waveforms of their action potentials or their adaptation properties. Both control antibodies had no significant effect on mechanoreceptors' sensitivities. Following removal of the FBmAb, the effects in some neurons were partially reversible. Taken together, the data from this study support the hypothesis that integrin alpha2beta1 plays a significant role in modulating mechanoreceptive response to compressive indentation.     

VIABLE LEISHMANIA DONOVANI IN NASAL AND ORAL SECRETIONS OF PATIENTS WITH KALA-AZAR AND THE BEARING OF THIS FINDING ON THE TRANSMISSION OF THE DISEASE

1. Smears from the nasal cavities of fifteen patients suffering from kala-azar have been examined and in nine of these typical Leishman-Donovan bodies have been found. 2. Smears from the surface of the tonsil and from the saliva in one of the above nine cases showed the presence of leishmania. The tonsils of this patient, who died as the result of kala-azar and secondary infection, at autopsy were shown to be massively infected with Leishman-Donovan bodies. 3. Leishmania in the nasal discharge of two patients were shown by inoculation into susceptible animals to be viable and capable of producing infection. Sufficient time has not elapsed to determine the viability of the organisms from the remaining cases. 4. These experiments show for the first time that a rich source of infective material from a large proportion of patients with kala-azar is available for direct transmission of the disease. 5. Strong evidence is presented as a basis for the concept that one of the natural modes, perhaps the most important natural mode, of transmission of kala-azar is from person to person by way of the upper respiratory and alimentary tracts. 6. Two normal human volunteers and numerous normal experimental animals have been inoculated into the nasal and oral cavities with the nasal discharge, known to contain leishmania, from patients with kala-azar. The results of these experiments will be reported at a subsequent date.     

THE ANTIGENIC RELATIONSHIP BETWEEN PROTEUS X-19 AND TYPHUS RICKETTSIAE : A STUDY OF THE WEIL-FELIX REACTION

1. The absorption of typhus sera (human or antityphus horse serum) with Proteus X-19 removes only the Proteus agglutinins, leaving the Rickettsia agglutinins intact. 2. The absorption of typhus sera with Mexican Rickettsiae removes the agglutinins for both the Rickettsia and Proteus X-19. 3. While normal or formalinized Rickettsiae are not agglutinated by anti-Proteus serum, these organisms—when formalinized and heated at 75°C.—become agglutinable by such serum. 4. The absorption of anti-Proteus serum with Mexican Rickettsiae removes agglutinins for formalinized and heated Rickettsiae but does not affect those for Proteus X-19.