[Chemistry of the cyclic tautomer of tryptophans]

A historical development of the chemistry of cyclic tautomer of tryptophan is reviewed. The cyclic tautomer of tryptophan, pyrrolo [2,3-b]indole-2-carboxylic acid, was prepared by dissolving N-methoxycarbonyltryptophan ester derivatives in 85% phosphoric acid or trifluoroacetic acid. The cyclic tautomer can be reverted to the indolic form with a dilute acid. The cyclic tautomer is an aniline derivative and the enamine reactivity of the indole ring in tryptophan is protected. The electrophilic substitution and oxidation of these cyclic tautomers opened a new method to prepare 5-substituted and/or 6-substituted tryptophan derivatives such as 5-bromo-, 5-hydroxy, and 6-methoxy-tryptophans. The formation and reactions of cyclic tautomers of diketopiperazines containing tryptophan and 3-indoleacetamide are also discussed. Some indole alkaloids having substituents at the benzene ring such as fumitremorgins, flustramine B, and eudistomines were synthesized by the use of these reactions. Furthermore, enantioselective alkylations of the carbanion at the 2-position of the cyclic tautomer established a new route to optically pure alpha-substituted tryptophans. The 2,3-dehydro derivative of the cyclic tautomer is an alpha, beta-unsaturated ester and was found to be a good precursor of optically pure beta-substituted tryptophans. The 3a-position of the cyclic tautomer is a benzylic position and subjected to radical reactions to give 3a-substituted-pyrroloindoles.

Enteral absorption of insulin in rats from mucoadhesive chitosan-coated liposomes

PURPOSE

The mucoadhesiveness of polymer-coated liposomes was evaluated to develop a novel drug carrier system for oral administration of poorly absorbed drugs such as peptide drugs.

METHODS

Multilamellar liposomes consisting of dipalmitoylphosphati-dylcholine (DPPC)and dicetyl phosphate (DCP) (DPPC: DCP = 8:2 in molar ratio) were coated with chitosan (CS), polyvinyl alcohol having a long alkyl chain (PVA-R) and poly (acrylic acid) bearing a cholesteryl group. The adhesiveness of the resultant polymer-coated liposomes to the rat intestine was measured in vitro by a particle counting method with a Coulter counter. The CS-coated liposomes containing insulin were administered to normal rats and the blood glucose level was monitored.

RESULTS

The existence of polymer layers on the surface of liposomes was confirmed by measuring the zeta potential of liposomes. The CS-coated liposomes showed the highest mucoadhesiveness and the degree of adhesion was dependent on the amount of CS on the surface of the liposomes. The blood glucose level of rats was found to be significantly decreased after administration of the CS-coated liposomes containing insulin. The lowered glucose level was maintained for more than 12h after administration of the liposomal insulin, which suggested mucoadhesion of the CS-coated liposomes in the intestinal tract of the rats.

[Aerosolization of lactide/glycolide copolymer (PLGA) nanospheres for pulmonary delivery of peptide-drugs]

Lactide/glycolide copolymer (PLGA) nanospheres with nafarelin acetate (NA) used as a model peptide-drug have been developed by the emulsion-phase separation method in an oil phase as reported previously. In the present study, the aerosolization of nanospheres in dry and wet dispersion methods was investigated in vitro to evaluate their applications to pulmonary delivery of peptide-drug. The size distribution of aerosolized nanosphere dispersions and pulmonary deposition behaviors of inhaled particles were investigated using a lazer diffraction light-scattering particle sizer and an artificial model lung (Cascade Impactor: CI), respectively. It was found that the freeze-drying of nanospheres with a hydrophilic surface active agent effectively improved the inhalation behavior. Further, the mixing of nanospheres with lactose led to the reduction of their adhesion to an inhalation device (Spinhaler). It was supposed that the mists of nanosphere-suspension generated from a jet nebulizer might be inhaled into the lower bronchus and alveolus, because their respirable fraction (RF) value, i.e., the deposition percentage on stage 2 to 6 of CI, defined as a pulmonary inhalation index, reached a maximum of over 50%.

Improved static compression behaviors and tablettabilities of spherically agglomerated crystals produced by the spherical crystallization technique with a two-solvent system

PURPOSE

Poorly compressible crystals of acebutolol hydrochloride were agglomerated by the spherical crystallization technique with a two-solvent system to improve the compressibility for direct tabletting. The mechanism of improvements in static compression behaviors and tablettabilities of the spherically agglomerated crystals were investigated.

METHODS

The improvement of static compression behaviors of the agglomerated crystals was determined by measuring the stress relaxations and elastic recoveries of compressed powder of original and agglomerated crystals. The improved tablettability of agglomerated crystals was evaluated by the pressure transmission ratio upon compression, the ejection pressure for releasing the tablet from the die and the tablet strength, i.e., tensile strength required for breaking.

RESULTS

The higher relaxation pressure and the lower elastic recovery of the agglomerated crystals than of the original crystals were found. The pressure transmission ratio data showed that the friction pressures of the two crystals were similar during the compression period. The ejection pressure of the agglomerated crystals was lower than that of the original crystals. The tensile strength of the tablet of agglomerated crystals was greater than that of the original crystals.

CONCLUSIONS

The compressibility and tablettability of the spherically agglomerated crystals prepared by the spherical crystallization technique were much improved due to their increased plastic property and reduced adhesive property compared to the original crystals.

Characteristics of multimodal co-aggregation between Fusobacterium nucleatum and streptococci

The co-aggregation characteristics between Fusobacterium nucleatum and streptococci were examined to clarify the adherence factors participating in the co-aggregation. Nineteen strains of F. nucleatum were classified into 8 groups according to co-aggregation titer and inhibition by L-arginine, L-lysine and N-acetyl-D-galactosamine (or lactose). The inhibition activity was, however, very different from strain to strain. With two fusobacterial strains, two inhibitors, which were both inhibition negative on their own, completely inhibited the co-aggregation when used together in a mixture. In some co-aggregation pairs, the protease treatment of F. nucleatum inactivated one of the adherence factors, and resulted in the change of inhibition characteristics. These results indicate the multimodal co-aggregation of F. nucleatum with streptococci mediated by L-arginine-sensitive, L-lysine-sensitive, N-acetyl-D-galactosamine-sensitive and in some resistant factors, and that the adherence factor or factors participating the co-aggregation change according to the co-aggregation partners.

Desensitization of vascular tissue to parathyroid hormone and parathyroid hormone-related protein

Although PTH and PTH-related protein (PTHrP) are vasodilators, prolonged exposure to elevated levels of PTH is often associated with hypertension. We investigated the effects of prolonged incubation with PTH or PTHrP on arterial segments and cultured vascular smooth muscle cells (VSMC). PTH or PTHrP transiently relaxed precontracted arterial segments within 10 min. Additional PTH or PTHrP added after 40-min exposure to these peptides had little effect on vascular tone, whereas forskolin, isoproterenol, isobutylmethyl-xanthine, or acetylcholine were still potent. In fura 2-loaded VSMC, 5-min incubation with PTH or PTHrP attenuated angiotensin II (Ang II)-induced calcium mobilization, an effect that was reduced by preincubation of VSMC with PTH for 1.5 h. Similarly, 1.5-h preincubation with PTH or PTHrP decreased the cAMP response to these peptides but not to forskolin or NaF. Ang II potentiated the cAMP response to PTH and PTHrP but was also subject to desensitization. Nle8, 18Tyr34 bovine PTH(3-34) amide did not desensitize vascular tissue to PTH or PTHrP. Our results suggest that homologous desensitization to PTH or PTHrP in vascular tissue requires receptor stimulation, occurs proximal to G stimulatory protein, and impairs attenuation of calcium mobilization by PTH or PTHrP. This may be a mechanism by which vasodilator effects of these peptides are decreased with prolonged elevation of PTH levels.

Carotenoid synthesis in Streptomyces setonii ISP5395 is induced by the gene crtS, whose product is similar to a sigma factor

In many species of actinomycetes, carotenogenesis can be photoinduced. The capacity to respond to photoinduction is, however unstable and, in various strains of Streptomyces, is lost at a relatively high frequency. In Streptomyces setonii ISP5395, which normally produces no carotenoids, carotenoid-producing mutants can be obtained following protoplast regeneration. We report here the characterization of a gene, crtS, which was isolated from one such mutant and can confer on wild-type S. setonii ISP5395 cells the capacity to synthesize carotenoids. Sequence analysis of crtS reveals an open reading frame, which shows homology to genes that encode alternative sigma factors in Bacillus subtilis. We propose that crtS encodes a sigma factor which is necessary for the expression of a cryptic gene(s) for carotenoid biosynthesis in S. setonii ISP5395.

Single photon emission computed tomography in systemic lupus erythematosus with psychiatric symptoms

Single photon emission computed tomography (SPECT) with n-isopropyl-p-[123I]iodoamphetamine (IMP) was performed on 20 patients with systemic lupus erythematosus (SLE). Fifteen of the patients showed areas of hypoperfusion. All nine patients who had florid psychiatric manifestations at the time the SPECT was performed had hypoperfusion areas. Four patients who had abnormal SPECT findings during psychiatric remission had psychiatric exacerbation one to six months after the SPECT. Four patients who had no hypoperfusion during psychiatric remission had good psychiatric prognoses. Two patients who had no history of psychiatric abnormality but showed hypoperfusion had psychiatric manifestations one month after the SPECT. The IMP-SPECT may be useful as a biological marker that represents the activity of cerebral involvement underlying psychiatric manifestations and the presence of subclinical CNS involvement.

Nuclear magnetic resonance study and secondary structure determination of the antibiotic peptide, aibellin

Aibellin is a 20-residue peptide antibiotic that has been isolated from the fungus Verticimonosporium ellipticum. Sequence-specific assignment of the 1H- and 13C-NMR signals of aibellin in a methanol solution was achieved by using the two-dimensional NMR technique. Furthermore, its secondary structure was characterized by circular dichroism (CD) and NOESY spectra. The observed NOEs, 3JNHC alpha H coupling constants and amide hydrogen-deuterium (H-D) exchange rates show that the peptide consisted of two alpha-helices and a bent structure around a Pro-14 residue.

Effect of aibellin, a peptide antibiotic, on propionate production in the rumen of goats

Aibellin was administered in feed to goats (16 to 18 kg of BW) for 12 d. At 80 mg/d, the molar percentage of propionate in rumen fluid increased significantly in 8 d, and the effect lasted for as long as 10 d after administration ceased. Total VFA concentration, protozoa numbers, and NDF digestibility were not depressed significantly at this dosage but were reduced at 100 mg/d with little further increase in the molar percentage of propionate. Therefore, the optimal dosage of aibellin was 80 mg/d under our experimental conditions. In contrast, monensin (30 mg/d) and gramicidin D (60 mg/d) decreased total VFA concentration and protozoa numbers when supplemented to obtain molar percentages of propionate comparable to 80 mg/d of aibellin. From these results, aibellin may be easier and safer to use than monensin and gramicidin D to modify rumen fermentation.

Mucoadhesion of polymer-coated liposomes to rat intestine in vitro

Multilamellar liposomes consisting of dipalmitoyl phosphatidylcholine (DPPC) and dicetyl phosphate (DCP) in a molar ratio of 8:2 (DPPC:DCP = 8:2) were coated with three different types of polymers: chitosan, polyvinyl alcohol having a long alkyl chain, and poly(acrylic acid) bearing cholesterols. The existence of polymer layers on the liposome surface was confirmed by measuring the zeta potential of the liposomal particles. The mucoadhesive function of the polymer-coated liposomes was evaluated in vitro using rat intestine. A particle counting method using the Coulter counter was adopted to evaluate the adhesive % of liposomes. Chitosan coated liposomes showed the highest adhesive % among the polymer-coated liposomes tested. No adhesive % was observed for the non-coated liposomes. The adhesion of chitosan-coated liposomes to the intestine wall was confirmed by fluorescence microscopy using pyrene loaded liposomes.

Effects of joint distention in shoulder diseases

From 1982 to 1992 arthrography was performed in 3707 patients with painful shoulders to determine the role of the subscapular bursal obliteration in the pathogenesis of painful, stiff shoulders and to evaluate the effects of distention on the subscapular bursa. Three hundred thirty-nine patients were excluded from the study because of incomplete data, leaving 3368. There were 2391 male and 977 female patients; their average age was 39.2 years (range, 8-86 years). Obliteration was noted in 1156 patients (34.3%), and filling of the bursa was seen in 2212 patients (67.7%). Function was regained in 178 patients (5%) by fluid distention alone, and in 308 (8%) patients by additional forced motion. Thus, 486 shoulders (14%) underwent distention and mobilization successfully. The most effective motion was forced abduction and internal rotation. Four hundred fifteen subjects were evaluated clinically; immediate pain relief after distention and/or bursting of the subscapular bursa was noted in all. There was also a remarkable improvement in the range of motion in all subjects who underwent distention alone, or in combination with forced mobilization.

In vitro drug release behavior of D,L-lactide/glycolide copolymer (PLGA) nanospheres with nafarelin acetate prepared by a novel spontaneous emulsification solvent diffusion method

Nanospheres with D,L-lactide/glycolide copolymer (PLGA) were prepared as a biodegradable and biocompatible polymeric carrier for peptide drugs by a novel spontaneous emulsification solvent diffusion method. Nafarelin acetate (NA), a luteinizing hormone-releasing hormone analogue, was employed as a model peptide drug to investigate the encapsulation efficiency. The drug and PLGA, dissolved in an acetone-dichloromethane-water mixture, were poured into an aqueous solution of polyvinyl alcohol under moderate stirring at room temperature. Spontaneous emulsification arising from a rapid diffusion of acetone from the organic to the aqueous phase enables preparation of PLGA submicron spheres 200-300 nm in size. The entrapment of NA in nanospheres was improved by blending low molecular weight (Mw = 4500) PLGA with higher molecular weight PLGA due to the synergistic effect of the rapid deposition of PLGA and the ionic interaction between NA and PLGA. By coadmixing a small amount of negatively charged phospholipids such as dipalmitoyl phosphatidylglycerol or dicetyl phosphate, the leakage of water-soluble NA was further prevented. The NA encapsulated in PLGA nanospheres was more stable than native NA in acidic medium (pH = 1.2). The drug-release behavior from nanospheres suspended in the disintegration test solution no. 1 (Japanese Pharmacopeia XII) exhibited a biphasic pattern. It was found tht the initial burst of release might be due to the degradation of the PLGA chain, as monitored by gel permeation chromatography. At a later stage, the drug was released more slowly, the rate of which was determined by the diffusion of the drug in the porous matrix structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Kinins contribute to the improvement of insulin sensitivity during treatment with angiotensin converting enzyme inhibitor

Although angiotensin converting enzyme inhibitors and alpha 1-blockers have been reported to improve insulin sensitivity, their mechanisms of action have not been elucidated. To investigate the role of kinins in insulin sensitivity, we treated 4-week-old spontaneously hypertensive rats with either an angiotensin converting enzyme inhibitor (enalapril), an alpha 1-blocker (doxazosin), or an angiotensin II antagonist (losartan) for 3 weeks. A control group received no drugs. In addition, 18 rats treated with enalapril or doxazosin received a simultaneous administration of a kinin antagonist (Hoe 140). Glucose clamp testing was performed in each group. Enalapril (128 +/- 1 mmHg) and doxazosin (132 +/- 2 mmHg) decreased mean blood pressure compared with control levels (148 +/- 1 mmHg) (P < .01). The glucose requirement for the clamp test during the administration of enalapril (25.8 +/- 0.5 mg/kg per minute) or doxazosin (28.6 +/- 0.7 mg/kg per minute) was higher than that of the control group (19.8 +/- 0.5 mg/kg per minute) (P < .05). Although Hoe 140 did not alter the glucose requirement of doxazosin (27.8 +/- 0.5 mg/kg per minute), it decreased that of enalapril (22.6 +/- 0.9 mg/kg per minute) (P < .05) without affecting the changes in mean blood pressure induced by enalapril. In addition, losartan decreased mean blood pressure but did not affect the glucose requirement. Thus, the improvement in insulin sensitivity produced by an angiotensin converting enzyme inhibitor is mostly dependent on kinins but not on angiotensin II antagonism, and an alpha 1-blocker improves insulin sensitivity irrespective of kinins.

Preparation of agglomerated crystals for direct tabletting and microencapsulation by the spherical crystallization technique with a continuous system

Adhesive and cohesive properties of chlorpromazine hydrochloride (CP) crystals were modified to improve their powder processing, e.g., direct tabletting and microencapsulation, by agglomeration. Moreover, sustained-released gelling microcapsules of CP were devised to prolong the pharmacological effect. The spherical crystallization technique was applied to prepare agglomerates for direct tabletting and microencapsulation to use them as core materials. The ethanolic solution dissolving CP was poured into a stirred cyclohexane, yielding spherically agglomerated crystals. The resultant agglomerates were free-flowing and easily packable spheres with average diameters of 200 to 1000 microns. The agglomerates reserved the high compressibility of the original powder having a small particle size (14 microns). The compression behavior represented by Heckel's equation suggested that the agglomerates were disintegrated to individual primary crystals at low compression pressures, and then they were closely repacked and plastically deformed at higher pressures. After agglomeration, microencapsulation was continuously performed in the same batch by a phase separation method. Coacervate droplets produced by pouring cyclohexane into a dichloromethane solution, dissolving polyvinyl acetate as a coating polymer, were added to the crystallization system under stirring, to prepare the microcapsules. By filling the microcapsules in gelatin hard capsules or tabletting them, their drug release rates became retarded compared with the physical mixture treated in the same way, having the same formulation as the microcapsules. This phenomenon was due to the gelation of polyvinyl acetate of the microcapsules in the dissolution medium, whose glass transition temperature is very low. This novel sustained-release dosage form is termed "gelled microcapsules."

Parathyroid hormone analogues inhibit calcium mobilization in cultured vascular cells

Parathyroid hormone and parathyroid hormone-related protein lower blood pressure and relax contracted arteries. Parathyroid hormone also attenuates angiotensin II-induced vasoconstriction. To determine the cellular mechanism or mechanisms by which parathyroid hormone analogues antagonize pressor effects, we examined the effect of these peptides on angiotensin II-induced calcium mobilization in fura 2-AM-loaded cultured rat vascular smooth muscle cells. Either 100 nmol/L parathyroid hormone or parathyroid hormone-related protein significantly reduced the amount of calcium mobilized by 100 nmol/L angiotensin II. The attenuating effect of these peptides was mimicked by 10 mmol/L forskolin and 10 mmol/L isobutylmethylxanthine and was not dependent on the presence of extracellular calcium. This effect of the parathyroid hormone analogues was reduced when cells were pretreated with 100 mmol/L 2',5'-dideoxyadenosine, an adenylate cyclase inhibitor. Combined inhibition of cyclic nucleotide-dependent protein kinases eliminated the inhibitory effect of parathyroid hormone, whereas protein kinase C inhibition had no effect. Parathyroid hormone analogues decreased the amount of calcium released by inositol 1,4,5-trisphosphate in digitonin-permeabilized vascular smooth muscle cells. This effect was inhibited by treatment with 2',5'-dideoxyadenosine. These results suggest that these peptides attenuate inositol 1,4,5-trisphosphate-sensitive calcium mobilized by angiotensin II via an adenylate cyclase-dependent mechanism. This may be a mechanism by which acute administration of parathyroid hormone or parathyroid hormone-related peptide antagonizes vasoconstriction.

Hemodynamic changes in the head and neck after ligation of the unilateral carotid arteries: a study using color Doppler imaging

For evaluation of the hemodynamics of the collateral circulation to the ligated external carotid artery (ECA) region, we measured the blood flow direction and volume in branches of the ECA in patients with unilateral carotid artery ligation before and during digital suppression of the common carotid artery (CCA) on the ligated and nonligated sides with color Doppler imaging and angiography. The main collateral pathway to the ligated ECA region was the ipsilateral occipital artery through Richter's anastomosis from the vertebral artery in the case of unilateral ECA ligation, and was the contralateral carotid artery in the case of unilateral CCA, ECA, and internal carotid artery resection. The superior and inferior labial arteries were important as the collateral pathway from the contralateral ECA.

Erythropoietin production in hepatocellular carcinoma cells associated with polycythemia: immunohistochemical evidence

Patients with hepatocellular carcinoma sometimes have erythrocytosis and high plasma erythropoietin levels. However, previous studies have not revealed direct evidence that the carcinoma cells produce the erythropoietin. To address this question, we carried out light and electron microscopic immunohistochemical studies, using a human erythropoietin antibody to the liver in three male patients with hepatocellular carcinoma and erythrocytosis. alpha-Feto-protein localization was also examined in serial liver sections by light microscopic immunohistochemistry with an antibody to alpha-fetoprotein. All three patients demonstrated high hemoglobin levels (16.7, 17.6 and 18.1 gm/dl) and high plasma erythropoietin levels (227, 266 and 280 mU/ml). In one patient the plasma erythropoietin level in the hepatic vein was significantly higher than that in the hepatic artery. The levels of plasma erythropoietin, as well as such tumor markers for hepatocellular carcinoma as serum alpha-fetoprotein and plasma des-gamma-carboxyprothrombin, were significantly reduced after treatment with an anticancer drug, cisplatin. Light microscopic immunohistochemistry showed that erythropoietin was definitely present in the cytoplasm of the hepatocellular carcinoma cells, but not in normal hepatocytes around the carcinoma lesion or in other nonparenchymal cells such as vascular endothelial cells and Kupffer cells. In electron microscopic immunohistochemistry, reaction products for erythropoietin were revealed in the cisternae of the endoplasmic reticulum in the carcinoma cells, suggesting the production of erythropoietin by these cells. Light microscopic immunohistochemistry showed that alpha-fetoprotein was localized in the hepatocellular carcinoma cells that were erythropoietin positive in the serial sections. These findings indicated that hepatocellular carcinoma cells produced erythropoietin as well as alpha-fetoprotein in these cases, leading to the complication of erythrocytosis.

Insulin attenuates agonist-mediated calcium mobilization in cultured rat vascular smooth muscle cells

Insulin has been shown to attenuate pressor-induced vascular contraction, but the mechanism for this vasodilatory action is unknown. This study examines the effect of insulin on angiotensin II (ANG II)-induced increments in cytosolic calcium in cultured rat vascular smooth muscle cells (VSMC). 20-min incubations with insulin (10 microU/ml to 100 mU/ml) did not alter basal intracellular calcium concentration ([Ca2+]i), but inhibited the response to 100 nM ANG II in a dose-dependent manner (ANG II alone, 721 +/- 54 vs. ANG II + 100 mU/ml insulin, 315 +/- 35 nM, P < 0.01). A similar effect of insulin on ANG II action was observed in calcium poor buffer. Moreover, insulin did not effect calcium influx. ANG II receptor density and affinity were not affected by 24-h incubation with insulin. To further clarify the mechanisms of these observations, we measured ANG II-induced production of inositol 1,4,5-triphosphate (IP3), and IP3-releasable 45Ca. Insulin treatment did not alter ANG II-stimulated IP3 production. However, IP3-stimulated release of 45Ca in digitonin permeabilized cells was significantly reduced after 5-min incubations with 100 mU/ml insulin. Thapsigargin induced release of calcium stores was also blocked by insulin. Thus, insulin attenuates ANG II-stimulated [Ca2+]i primarily by altering IP3-releasable calcium stores. Insulin effects on ANG II-induced [Ca2+]i were mimicked by preincubation of VSMC with either sodium nitroprusside or 8-bromo-cGMP. As elevations in cGMP in vascular tissue lower [Ca2+]i, it is possible that insulin affects IP3 release of calcium by a cGMP-dependent mechanism that would contribute to its vasodilatory effects.

Effects of aibellin, a novel peptide antibiotic, on rumen fermentation in vitro

A new icosapeptide, aibellin, markedly modified rumen fermentation in vitro. Batch culture experiments with mixed rumen microorganisms showed that 12.5 to 25 mg/L of aibellin enhanced propionate production and reduced methanogenesis without significantly affecting production of total VFA, protozoal survival, or cellulose digestion. Aibellin had essentially the same effects in continuous culture with hay powder and concentrate. Monensin (5 mg/L) had similar effects on propionate production and methanogenesis, but total VFA, protozoa, and cellulolysis were decreased even by this low concentration of monensin. Commercially available peptide antibiotics also were compared with aibellin. Of the antibiotics examined, only graminicidin D (7.5 to 15 mg/L) enhanced propionate production and reduced methanogenesis. However, gramicidin D decreased total VFA, protozoa, and cellulolysis even at 7.5 mg/L. Alamethicin (7.5 to 15 mg/L), which resembles aibellin in its structure, did not increase propionate production but raised the percentage of propionate because of reduced production of total VFA. Alamethicin depressed methanogenesis but also decreased protozoal survival and cellulose digestion. These in vitro experiments indicate that aibellin could be a useful and potent modifier of rumen fermentation.

Role of the solvent-diffusion-rate modifier in a new emulsion solvent diffusion method for preparation of ketoprofen microspheres

A new emulsion solvent diffusion method to prepare the microspheres of ketoprofen with an acrylic polymer was developed by utilizing sugar esters as solvent diffusion modifiers. The microspheres were produced via transient o/w emulsion droplets of the polymer, which was formed by the interaction of drug and water-miscible organic solvent, e.g. ethanol. The solvent consisting in oil droplets diffused into the outer aqueous medium. In the droplets, ethanol interacted with ketoprofen via hydrogen bonding between -OH group of ethanol and both -COOH and = CO groups of ketoprofen. These hydrogen bonds made ethanol solution strongly hydrophobic. The sugar ester added in the ethanol could inhibit such intermolecular interaction between ethanol and the = CO group of ketoprofen. Modulation in the binding force of ketoprofen-ethanol by the sugar ester contributed to achieving a desirable initial ethanol diffusion rate from the oil droplets for the formation of ketoprofen microspheres with high yield (> 85 per cent) and drug entrapment ratio (> 90 per cent).

Fatal acute hepatitis B virus infection while receiving immunosuppressants after renal transplantation

A 47-year-old man with acute hepatitis B virus (HBV) infection who had been receiving immunosuppressants after renal transplantation developed progressive liver failure. During the clinical course (approximately 7 months), anti-HBc IgM antibody and HBV-DNA polymerase levels remained high, but the serum alanine aminotransferase (ALT) level was consistently less than 150 K.U. Histopathologic examination of the liver showed submassive hepatic necrosis without significant inflammation accompanied by marked fibrosis. Most hepatocytes showed strong nuclear expression of HBc antigen by immunohistochemical staining and electron microscopy revealed numerous intranuclear core-like particles. Hepatitis B virus infection in immunosuppressed individuals occasionally insidiously progresses, resulting in liver failure. The clinical course of such patients thus merits close scrutiny.

A study of erythrocyte C3b receptors (E-CR1) in patients with acute viral hepatitis

Erythrocyte C3b receptors (E-CR1) were assayed by ELISA in 16 patients with acute viral hepatitis. In 13 patients with hepatitis type A, type B, or type non-A non-B, the E-CR1 level was significantly lower in the acute phase than in healthy controls, and recovered in the convalescent phase. The E-CR1 levels in 3 patients with non-A, non-B hepatitis remained below the mean level of the healthy controls. These findings suggest that the E-CR1 level fluctuates in acute viral hepatitis, and that it continues to be reduced in some patients with non-A non-B acute hepatitis.