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The phase behavior of a new psedoternary system of clove oil/Tween 20 has been studied. Several compositions from the single-phase region were selected and their stability toward time, temperature, and electrolytes has been examined. A particular composition(clove oil/Tween 20/water as 5/30/65) was chosen as the drug delivery system from the clear oil-in-water zone of the pseudoternary system. The droplet dimension and the polydispersity state of the particular composition was determined by dynamic light scattering. A bioactive compound quarcetin was encapsulated in the vehicle. The efficacy of the drug in the vehicle was examined against leishmaniasis in hamster models. The hepatotoxicity of the vehicle (o/w microemulsion) with and without the drug quarcetin was examined by estimating serum alkaline phosphatase, glutamate pyruvate transaminase, urea, and creatinine.

An antileishmanial compound, 14-deoxy-11-oxo-andrographolide, a derivative of andrographlide, isolated from the Indian medicinal plant Andrographis paniculata was evaluated for efficacy in free form and in different vesicular delivery modes on hamster model of Leishmaniasis. The subcutaneous injection of free drug reduced the spleen parasite load by 39%, whereas for drug incorporated in liposomes, niosomes and microspheres, reductions in the parasite load were 78%, 91% and 59%, respectively. Moreover, the drug in various delivery modes, particularly in liposomal and niosomal forms, showed no apparent immediate toxicity. Although an inverse linear relationship between the size of carriers and per cent efficacy in reduction of spleen parasite load was established, involvement of other factors such as drug release profiles or rates remains an open question. Because of greater efficacy and lesser toxicity, liposomal, niosomal and possibly microsphere-incorporated 14-deoxy-11-oxo-andrographolide might have clinical application to combat visceral Leishmaniasis.

Novel phospholipid microspheres were prepared from polylactic-co-glycolic acid (PLGA) and phosphatidyl ethanol amine in the molar ratio 1:71, to deliver drugs to macrophages in experimental leishmaniasis. Liposomes, well known as drug carrier systems, made from phosphatidylethanolamine, cholesterol and dicetyl phosphate in the molar ratio 7:2:1, were used as control, in order to compare the efficacies of the two carriers. As such, the membrane fluidity of the two carriers was kept at comparable levels by adjusting chemical composition. Moreover, because of the presence of mannosyl fucosyl receptors on macrophages, attempts were made to target an optically active synthetic compound dihydroindolo [2,3-a] indolizine, an antileishmanial agent, intercalated in both mannose-grafted liposomes and mannose-grafted microspheres. When tested for efficacy in lowering parasite load in the spleen, as well as in reducing the hepatic and renal changes associated with infection, the drug intercalated mannose-grafted microspheres were found to be the most active in comparison to drug intercalated liposomes or to the free drug. Thus, mannose-grafted microspheres may have possible application in the clinics not only in visceral leishmaniasis, but also in other macrophage-associated disorders.

Chemotherapy is still a major challenge for in vivo drug targeting to macrophages. Toxicity remains the major obstacle for the most potent drugs already known in the therapy of leishmaniasis. Thus, new drugs and new delivery systems are sought. By using different vesicular delivery modes e.g. liposomes, niosomes, microspheres and nanoparticles, attempts have been made to deliver an indigenous antileishmanial compound, quercetin, to treat experimental leishmaniasis in the hamster model so as to increase its efficacy as well as to reduce the toxicity. At equivalent quercetin concentration, the nanocapsulated quercetin was found to be the most potent in reducing the parasite burden in the spleen as well as in reducing hepatotoxcity and renaltoxicity compared to free drug or drug in other vesicular forms. An inverse relationship between the efficacy and the size of the vesicles was established. Such a drug vehicle formulation especially in the nanocapsulated form may be considered for clinical trials.

Bacopasaponin C, an indigenous glycoside, was isolated from Indian medicinal plant Bacopa monniera (b. brahmi) and was tested for antileishmanial properties both in free and in various delivery modes, e.g., niosomes, microspheres, and nanoparticles that are used now as alternatives to more commonly used liposomes. The different vesicles were prepared by published protocols. The percent intercalation of Bacopasaponin C in liposomes, niosomes, and micropspheres determined at its absorption maximal (lambda(max) = 238 nm, epsilon = 8.6 x 10(3) M(-1) x cm(-1)) was found to be 30; for nanoparticles it was 50. At equivalent dose of 1.75 mg/kg body weight, every third day for a total of 6 doses in 15 days, Bacopasaponin C in all the vesicular forms was found to be very active. An inverse linear relationship between the efficacy and the size of the vesicles was established. As analyzed from tissue histology, blood pathology, and specific tests related to normal liver and kidney functions, Bacopasaponin C in each of the four vesicular forms was found to be without any side effects. Thus, because of its indigenous origin and non-toxic nature, Bacopasaponin C could very well be considered for application in the clinic through these alternative delivery modes.

The effect of oxidants and the anti-inflammatory steroid dexamethasone on the attachment and internalization of virulent and avirulent Leishmania donovani promastigotes by the macrophage mannosyl fucosyl receptor was examined. Oxidants and dexamethasone are known to down- and upregulate the expression of the mannose receptor. Macrophages, when treated with 500 microM H2O2 at 37 C for 30 min, stimulate about 45% inhibition in uptake of an avirulent strain (UR6), and 30 and 25% inhibition for virulent strains AG-83 and GE-I, respectively. Treatment of macrophages with dexamethasone for 20 hr resulted in a stimulation in uptake of the parasite. When UR6 was used, a 3-fold increase in uptake was observed compared with the controls. Parasite uptake was also inhibited by the H2O2-generating system, glucose/glucose oxidase; inhibition was blocked by catalase. Treatment of macrophages either with H2O2 or dexamethasone did not affect the binding of the advanced glycosylation end product-bovine serum albumin (AGE-BSA), the ligand for AGE receptor of macrophages. Similarly, indirect evidence also shows that both types 1 and 3 complement receptors (CR1, CR3) are not affected by these treatments, indicating that, besides the mannosyl fucosyl receptor, other receptors are minimally altered in the identified condition. These results suggest that the up- and downregulation of the mannose receptor of macrophages may play a role in affecting L. donovani infection.

Summary: Sequence analysis using Web Resources (SeWeR) is an integrated, Dynamic HTML (DHTML) interface to commonly used bioinformatics services available on the World Wide Web. It is highly customizable, extendable, platform neutral, completely server-independent and can be hosted as a web page as well as being used as stand-alone software running within a web browser.

Liposome-encapsulated antioxidants have been tested in vivo to prevent oxidative attack during cerebral ischemia and reperfusion. Oxidative stress is a causal factor in the neuropathogenesis of ischemic-reperfusion injury. From the therapeutic point of view free chemical antioxidants were almost ineffective to protect cerebral tissues from those oxidative attacks. Thus an attempt has been made to prevent the oxidative damage due to the cerebral ischemic insult by the introduction of chemical antioxidants, ascorbic acid and alpha-tocopherol either encapsulated or intercalated in small unilamellar liposomes. The effectiveness of antioxidant-loaded liposomes was tested against an experimental in vivo rat model of global cerebral ischemia. Oxidative free radical attack on cerebral tissues by the ischemic insult and brief reperfusion was accounted for by the amount of diene production per unit of tissue protein. Diene production in ischemic reperfused rat brain increases almost twofold over that of the normal rats. Prevention of excess diene production has been attributed to rats when they were treated either with L-ascorbic acid-encapsulated liposomes or alpha-tocopherol intercalated liposomes 2 hours prior to the cerebral ischemic insult. Complete restriction of excess diene generation has also been achieved when a mixture of alpha-tocopherol and L-ascorbic acid-encapsulated liposomes were injected 3 hours before the ischemic infraction.

The fMLP receptor of peritoneal macrophages stimulated by fMLP grafted liposomes as ligand, was analysed and compared with respective controls for its ability to promote killing of intracellular Leishmania parasites. fMLP grafted liposomes show greater efficacy in killing intracellular L. donovani (MHOM/IN/1983/AG83) parasites in a time dependent manner than free fMLP. fMLP grafted liposomes also release more active oxygen intermediates and reactive nitrogen intermediates (O2-, H2O2, NO) than free fMLP. The key enzymes PKC and PTK for the respiratory burst and nitric oxide generation were found to be important in this fMLP receptor mediated signaling process as the enzyme specific inhibitors viz. staurosporine, genistein and AG126 suppressed the leishmanicidal effect of fMLP grafted liposomes. The above findings suggest that the fMLP receptor of macrophages activates PKC and PTK mediated signalling that is responsible for the intracellular parasite killing.

Despite the rapid development in medicinal and pharmaceutical technology, the targeting of drugs to phagocytic cells in macrophage-related diseases still remains a major unsolved problem. By using the mannosyl-fucosyl receptors on macrophages, attempts were made to target antileishmanial drugs encapsulated in mannosylated or fucosylated liposomes to treat experimental leishmaniasis in the hamster model. Mannosylated liposomes were found to be more potent in delivering antileishmanial drugs to phagocytic cells. Liposomes loaded with an indigenous drug, andrographolide, a labdane diterpenoid isolated from Indian medicinal plant Andrographis paniculata, were prepared and tested against experimental leishmaniasis in a hamster model. Mannosylated liposomes loaded with the drug were found to be most potent in reducing the parasitic burden in the spleen as well as in reducing the hepatic and renal toxicity. In addition, mannosylated drug-loaded liposome-treated animals showed a normal blood picture and splenic tissue histoarchitecture when compared with those treated with free drug or regular liposomal drug. Such a drug-vehicle formulation may be considered for clinical trials.

Fc receptors are known to express on the surface of mature monocytes, macrophages and lymphocytes. In this study a ligand e.g. liposomal IgG (human IgG coupled to PE-liposome via carbodimide reaction) was developed to ligate the Fc receptor of macrophages. When liposomal IgG was incubated with macrophages at 37 degrees C for 5 min, it induced the macrophage activation which suppress the parasite burden approximately to an extent of 60%, 50% and 45%, when macrophages were infected with UR6, AG83 and GE1 strains of L-donovani respectively. Superior efficacy of liposomal IgG were achieved compared to the treatment with free IgG and free liposomes. The activity of protein kinase C (PKC) has been found to be higher in the Fc receptor targeted macrophage membrane fraction, suggesting its translocation from the cytosol. Staurosporine, a potent inhibitor of the enzyme protein kinase C (PKC) has been found to protect the parasite inside the macrophage indicating the role of PKC in the signaling process. The liposomal IgG treatment has been found to induce the generation of significant amount of superoxide and hydrogen peroxide which helped to suppress the parasite burden. Further when liposomal IgG were incubated with IFN-gamma primed, LPS activated macrophages, a significant amount of NO release was also noticed, indicating its role in parasite killing. The above results suggest that Fc receptor mediated activation by liposomal IgG may be used as an alternative approach to kill parasites intracellularly.

Pretreatment of macrophages with, an agonist of PKC, showed diverse effects on degradation and survival of two virulent strains of Leishmania donovani promastigotes. Treatment of macrophages with PMA for 45 min at 37 degrees C generated significant amounts of superoxide anions and reduced the parasite burden of macrophages by up to 48 and 43% when AG83 and GE-1 strains were used for infection. Staurosporine, an inhibitor of PKC, inhibited PMA-dependent killing of the parasites, while tyrphostin AG 126, an inhibitor of protein tyrosine kinase, showed very little effect. Depletion of PKC by prolonged incubation with PMA drastically reduced the superoxide anion generation and increased the uptake and multiplication of the parasites. Finally, to understand the mechanism of higher uptake of the parasites by PKC-depleted macrophages, membrane microviscosity was measured by fluorescence depolarization. Membrane microviscosity was found to be approximately 40% lower in PKC-depleted macrophages than in normal macrophages, indicating the role of membrane fluidity in the infection process. Together, these data suggest PKC activation, superoxide generation, and membrane fluidity are essential factors in the efficient regulation of leishmanial infection.

The alternate pathway of signal transduction via hydrolysis of phosphatidylcholine, the major cellular phospholipid, has been investigated in murine peritoneal macrophages. A sustained formation of diacylglycerol, is preceded by an enhanced production of phosphatidic acid, when the macrophages were given a stimulus with 12-O-tetradecanoyl phorbol-13-acetate for sixty minutes. Production of choline and choline metabolites are significantly increased too. Propranolol, which inhibits phosphatidate phosphohydrolase, the enzyme responsible for conversion of phosphatidic acid to diacylglycerol, can effectively block the formation of diacylglycerol. Inhibition of protein kinase C either by its inhibitors, staurosporine and H-7 or by depletion, apparently affect the generation of the lipid products. Moreover, based on the results of transphosphatidylation reaction, involvement of a phospholipase D in the phosphatidylcholine-hydrolytic pathway in macrophages is predicted. These observations support the view that probably the phorbol ester acting directly on protein kinase C of the macrophages activate their phosphatidylcholine-specific phospholipase D to allow a steady generation of second messengers, to enable them to participate in the cell signalling process in a more efficient manner than those generated in the phosphoinositide pathway of signal transduction.

The antileishmanial property of amarogentin, a secoiridoid glycoside isolated from the Indian medicinal plant Swertia chirata, was examined in a hamster model of experimental leishmaniasis. The therapeutic efficacy of amarogentin was evaluated in free and two different vesicular forms, liposomes and niosomes. The amarogentin in both liposomal and niosomal forms was found to be a more active leishmanicidal agent than the free amarogentin; and the niosomal form was found to be more efficacious than the liposomal form at the same membrane microviscosity level. Toxicity studies involving blood pathology, histological staining of tissues and specific enzyme levels related to normal liver function showed no toxicity. Hence, amarogentin incorporated in liposomes or niosomes may have clinical application in the treatment of leishmaniasis.

A series of potential 9-anilinoacridine antitumor agents, 3-(9-acridinylamino)-5-hydroxymethylaniline (AHMA) derivatives with monosubstituent at C4' and disubstituents at C4' and C5' of the acridine ring and their alkylcarbamates, were synthesized for evaluation of their antitumor activity. A structure-activity relationship (SAR) study showed that the AHMA-alkylcarbamates were more potent than their corresponding parent AHMA compounds. In addition, the cytotoxicity of the AHMA-alkylcarbamate decreased with increasing length and size of the alkyl function. Among these compounds, AHMA-ethylcarbamate (18) and 4'-methyl-5'-dimethylaminoethylcarboxamido-AHMA-ethylcarb amate (34) possess potent cytotoxicity on the inhibition of human leukemic HL-60 cell growth in culture. Further in vivo studies of these compounds displayed significant anticancer therapeutic effects in mice bearing sarcoma 180, Lewis lung carcinoma, and P388 leukemia.

Studies have been performed to assess the possibility of using small unilamellar liposomes as therapeutic carriers to the brain of hypertensive rats. Rats were made temporal hypertensive by the infusion of angiotensin II (AII; 15 micrograms in 1 ml) through their right common carotid artery. Another control group was infused with physiological saline. Free 125iodine-BSA (125I-BSA) and 125I-BSA encapsulated liposomes (average diameter approximately equal to 100 nm) were injected in the tail vein 2 min after the infusion of AII or saline. Plasma radioactivity was monitored at different times up to 15 min when the cerebral uptake of 125I-BSA was determined. While a little variation in plasma clearance pattern of liposomes in hypertensive and control group was noticed, the uptake by cerebral tissues was markedly higher in hypertensive group. Analysis of pharmacokinetic parameters in relation to cerebral uptake indicated AII induced a short term opening of the blood-brain barrier (BBB) resulting in an increased cerebral uptake. Positively charged liposomes was found to be most effective in hypertensive state.

The leishmanicidal property of piperine intercalated in liposomes and in mannose-coated liposomes was tested in experimental visceral leishmaniasis in hamsters. Mannose-coated liposomal piperine eliminated intracellular amastigotes of Leishmania donovani in splenic macrophages much more efficiently than did the liposomal piperine or free piperine. At a dose equivalent to 6 mg/kg body wt every 4th day for a total of 4 doses in 12 days, the mannose-coated liposomal piperine was found to reduce spleen parasite load to the extent of 90% in comparison to that achieved by liposomal piperine (77%) or free piperine (29%). Histological examination of spleen and liver function tests showed that the toxicity of piperine was reduced when mannosylated liposomal piperine was administered.

Antisense oligonucleotides have been considered as inhibitors of growth of intracellular parasites such as Leishmania, but only limited inhibition has been observed in vitro. We have encapsulated an antisense oligonucleotide, complementary to the Leishmania universal miniexon sequence, in cationic liposomes. Low concentrations (4 microM) of encapsulated oligonucleotides specifically reduced the amastigote burden within cultured macrophages by 80%. This result illustrates the importance of effective delivery for efficient antiparasitic activity of antisense oligonucleotides.

The interaction of leishmania parasites with macrophages is known to be receptor mediated. Previous study from this laboratory (J. Parasitol. 82:632, 1996) showed the significant involvement of LPG and gp63 receptors in the recognition of virulent strains onto the macrophages. The role of carbohydrate receptors the other major receptors besides LPG and gp63 receptors, in the recognition of both virulent (strains AG83 and GE1) and avirulent (strain UR6) leishmania onto the host macrophages has been the major focus of the present investigation. Various neoglycoproteins were used as efficient ligands to preblock the carbohydrate receptors on the macrophage surface. Similarly, various sugar specific lectins were used to preblock the corresponding carbohydrate ligands on the parasite surface. When these preblocked macrophages or parasites were used to study their mode of recognition, it was obvious from the findings that avirulent leishmania promastigotes possibly use the mannosyl fucosyl receptors (MFR) more avidly for their initial attachment and subsequent internalization into the macrophages whereas the virulent leishmania exhibits limited use of this receptor. When a macrophage-like cell line (J774), lacking in MFR, was purposely selected to test the previous findings, as expected, the attachment of avirulent promastigotes (UR6) onto the cell line was found to be negligible when compared to the peritoneal macrophages. Thus, it appears that avirulent leishmania promastigotes probably utilize MFR significantly for their initial recognition and subsequent internalization by macrophages.

The interaction of chemotactic peptide (e.g., fMet-Leu-Phe)-grafted liposomes with macrophages is noted to be rapid and specific. At a grafted peptide concentration of 100 nmol, internalization of the peptide-grafted liposomes by the macrophages is found to reach equilibrium in 30 min. The peptide alone and the peptide-grafted empty liposomes are found to show moderate antileishmanial activity in vitro. Primaquine, which is known to generate O2- in phagocytic cells, showed leishmanicidal properties when it was tested in vitro against parasite-infected macrophages over a certain range of concentrations. It showed much better efficacy against experimental leishmaniasis when it was used in the fMet-Leu-Phe-grafted liposomal form in comparison with its efficacy when it was either in the free form or encapsulated in ungrafted liposomes. The conventional toxicity parameters (e.g., blood pathology and tissue histology-specific enzyme levels related to normal liver function) are found to be very close to normal when fMet-Leu-Phe-grafted liposomal primaquine is used. The biodegradabilities of both the drug and the delivery systems are also found to be very satisfactory. Thus, this delivery system may have possible applications for the treatment of leishmaniasis as well as other macrophage-associated disorders.

Objectives: Dental instruments such as the right angle or straight handpiece, air turbine, and ultrasonic scaler have the ability to produce dental aerosols containing water, saliva, microorganisms, blood, tooth particles, lubricating oil, and restorative materials. The purpose of this study was to find out whether personal protective equipment (mask, glasses) was used by dental personnel, and to investigate possible work related disease in the dental profession., Methods: Cross sectional data were collected with a self administered questionnaire sent to 69 randomly chosen general dental practices in the West Midlands Region. All members of the dental team completed questionnaires (dentists (n = 122); nurses (n = 115); hygienists (n = 86); and receptionists (n = 74) and answered questions on use of personal protective equipment and the prevalence of upper and lower respiratory tract, eye, and skin symptoms (reported and work related). Reception staff were included as a low exposure, control group. Also, a longitudinal study of dental hygienists was carried out on 31 people who had taken part in a similar study five years earlier., Results: Use of a face mask and glasses differed between clinical groups with hygienists and nurses being the most and least prevalent users respectively. Although several reported symptoms were significantly more prevalent among clinical staff, only one work related symptom (skin rashes or itchy or dry skin) was reported by the clinical staff more than by the non-clinical receptionists. Among female clinical staff, age < 35 years and atopy were the factors that predisposed to work related symptoms. Also, reported symptoms were related to duration of use of instruments that generated aerosols., Conclusions: This study shows a low level of work related symptoms in dentistry, but highlights a group vulnerable to prolonged exposures to dental aerosols. It also supports the need for enforcement of the use of personal protective equipment among dental nurses.

Survival or destruction of intramacrophage pathogen Leishmania depends in part on modulation of their host cell phagosome, capabilities of the infected macrophages to present parasite antigen to the host's immune system. Macrophages house these parasites as amastigotes in the acidic phagolysosomal compartment. Leishmania phagolysosome is the potential site for processing and presentation of its antigen as well as being the target site for chemotherapy in leishmaniasis. It is thought that the parasites are killed from macrophage activation by lymphokines secreted from either helper T1 cells or CD8+ T cells. Characterization of both the host and parasite molecules in the compartment in the context of biogenesis of Leishmania-phagolysosome and processing of the parasite antigen by this compartment are discussed. Trafficking of different drugs and new agents through this compartment and their role in chemotherapy and necessity of developing new drug carrier are also stressed.

Specific receptors may be involved in the process of attachment of Leishmania donovani promastigotes to macrophage surfaces and their subsequent internalization. Two virulent strains of Indian L. donovani (AG83 and GE-I) were found to enter into macrophages much faster than the avirulent ones (UR6). These virulent promastigotes express surface glycoprotein (gp63) and lipophosphoglycan (LPG) to a greater extent than avirulent strains. We examined their interaction with macrophages as a function of time by preblocking the macrophage receptors with the exogenous addition of gp33 or LPG. In experiments where gp63 was used as the blocking agent, the entry of one virulent strain (GE-I) was affected. In other experiments where LPG was used, the entry of another virulent strain (AG83) was affected. Entry of the avirulent strain (UR6) was unaffected by either of these treatments. Exposed LPG or gp63 on the surface of promastigotes thus appear to expedite their recognition and entry into the host cell. To assess the role of gp63 further in the entry of Leishmania into the macrophages, an avirulent UR6 strain was transfected with the gp63 gene cloned from L. amazonensis. The transfected UR6 as expected expressed more GP63 at a faster rate and entered into the macrophages like the virulent strain when compared to the nontransfected UR6 or UR6 transfected with vector alone. Thus, the expression of the gp63 gene is involved in the recognition and intracellular entry of visceral Leishmania into the macrophages in addition to the cutaneous species demonstrated previously.

Different sugar-grafted liposomes were prepared and tested against experimental leishmaniasis in vivo using the classical drug pentamidine isethionate and its methoxy derivative. Both the drugs, when encapsulated in sugar-grafted liposomes were found to be more potent in comparison to normal liposome-encapsulated drug or to the free drug. Moreover, the mannose-grafted liposomes were adjudged to be the best in lowering of spleen parasite load in comparison with those bearing glucose or galactose. When encapsulated in mannose-grafted liposomes the therapeutic efficacy of pentamidine isethionate was found to be better than that of its methoxy derivative, although the latter seemed to be less toxic than the pentamidine isethionate itself.

Peritoneal macrophages pretreated with different stimulants were analysed and compared with their respective controls for their ability to kill intracellular pathogenic L. donovani, (MHOM/IN/1983/AG83) an isolate from Indian subcontinent. Stimulation of macrophages by zymosan showed a higher microbicidal activity as compared to that by PMA. A correlation between microbicidal activity of the macrophages and the parameters related to respiratory burst activity such as liberation of O2-, production of H2O2 and consumption of O2 was sought. All the parameters showed a decrease in case of infected macrophages in comparison to those of the non-infected ones. Thus, it is possible that the impairment of macrophage activation by intracellular Leishmania contributes to their survival in the toxic environment of the host.

Asiaticoside, a plant glycoside with rhamnose as end sugar and having microbicidal properties was tested against Mycobacterium leprae and Mycobacterium tuberculosis both in vivo and in vitro. As rhamnose is reported to have no tissue specificity, corchorusin D having glucose as end sugar was used for targeting with an equimolar proportion of asiaticoside in liposomal form for testing the drug value. Results showed that liposomal asiaticoside had better microbicidal property against M. leprae and M. tuberculosis when compared to that of free asiaticoside whereas liposomes containing asiaticoside and corchorusin D were found to be equally or more active in comparison to liposomal asiaticoside alone. It is inferred that appropriate glycosides, if used in liposomal form (incorporated or covalently grafted) have enhanced drug efficacy and such glycoside bearing liposomes as targeted delivery systems could be used for chemotherapeutic control of several other diseases.

Liposomal hamycin was found to elicit enhanced microbicidal activity and reduced toxicity in experimental leishmaniasis in a hamster model under in vivo conditions. Mannose-coated liposomal hamycin was seen to produce increased therapeutic efficacy as judged from the lowering of spleen parasite load. At an equivalent dose of 0.5 mg/kg, every 3 days for a total of three doses in 7 days, the mannose-coated liposomal hamycin was found to be most effective compared to either of the liposomal hamycin or the free hamycin. Because of the reduced toxicity as judged from the blood pathology, tissue histology, and specific enzyme level related to normal liver function, mannose-coated liposomal hamycin resulted in 80 to 100% survival for a period of 15-18 days. Hamycin intercalated in sterol-rich liposomes showed reduced hemolytic activity but comparable therapeutic efficacy as was found with ordinary liposomes.

Receptors interacting with terminal sugars as ligands are involved in the binding of Leishmania donovani promastigotes to the macrophage surface and their subsequent internalization. Mannose and glucose are specifically involved in the binding process. Decreased binding occurs to macrophages already infected with L. donovani either in vivo or in vitro. When mannose- or glucose-bearing liposomes are used as ligands the binding shows similar trends and the percentage inhibition of binding with mannose-bearing liposomes increases when compared to that for the glucose-bearing ones. The decreased binding of the ligand seems to be due to a decrease in the number of receptors after infection. The affinity of the ligands for the binding sites either on the normal macrophages or on the infected macrophages apparently remains the same. The results based on the incorporation of [3H]phenyl alanine and supported by the binding of glycosylated liposomes to both infected and non-infected macrophages suggest that protein synthesis, in general, is suppressed in L. donovani-infected macrophages thus affecting also mannose/glucose receptor protein synthesis, resulting in fewer receptors on the macrophage surface.

Normal hepatic microsomal membranes when exposed in vitro to different free radicals, cause membrane damage by lipid peroxidation which could be monitored by the analysis of malonaldehyde formation and measurement of membrane microviscosity. Lipid peroxidation in vivo, when examined in hepatic microsomal membranes in experimental Leishmaniasis, reveals a direct relationship between membrane microviscosity and the extent of lipid peroxidation. Scavengers of free radicals and peroxides such as superoxide dismutase (SOD) for O2.-, mannitol for (OH.) and catalase for H2O2 in modest amounts were used for preventing the membrane damage caused by lipid peroxidation.

The uptake of glycoside-bearing liposomes by macrophages has been studied in vitro. Since the uptake was found to be specific for the end sugar attached to the glycoside, the possibility is raised that glycoside-bearing liposomes might be used in vivo as systems to deliver drugs to macrophages. Using the antileishmanial drug urea stibamine, these delivery systems have been tested in vivo against model leishmaniasis. The results indicate that the drug encapsulated in sugar-coated liposomes is much more potent in comparison with normal liposome-encapsulated drug or to the free drug. Mannose-grafted liposomes are more efficient in transportation of drugs compared with those bearing glucose. Toxicity studies involving blood parameters, histological staining of tissues and specific enzyme activities related to liver function, show no apparent toxicity with the drugs. Hence, drug encapsulated sugar-coated liposomes may have possible applications to humans.

The effect of erythropoietin (Ep), a glycoprotein hormone, has been studied on lipid peroxidation induced by Cu2+ and ascorbate in vitro, Mg2+ ATPase activity and spectrin of RBC membrane. Our present investigation reveals that Cu2+ and ascorbic acid increases lipid peroxidation of RBC membrane significantly. It has further been observed that under the same experimental condition spectrin, a major cytoskeleton membrane protein, and Mg(2+)-ATPase activity of RBC membrane decrease significantly. However, exogenous administration of Ep completely restores lipid peroxidation and Mg(2+)-ATPase activity and partially recovers spectrin of RBC membrane.

This article presents a case of gingival Kaposi's sarcoma that initially mimicked an acute periodontal infection, but was the first clinical sign of HIV infection in a 38-year-old male homosexual patient. The clinical features and treatment of oral Kaposi's sarcoma are discussed and the variable histopathology of the lesion is demonstrated.

Two cases with exuberant papillary and nodular hyperplasia of the hard and soft palates are described. Both were elderly edentulous men with bilateral angular stomatitis. The papillary hyperplasia extended as far as the epiglottis and was associated with swelling and fissuring of the upper lip in patient 1. In patient 2, the palatal change extended to the maxillary gingiva and was associated with smooth plaques and fissuring of the dorsal tongue. Histology of both cases showed a dense polyclonal plasma-cell infiltrate with overlying epithelial hyperplasia, parakeratinization and neutrophil micro-abscesses suggesting Candida infection but fungal elements could not be demonstrated. Patient 1 also showed defective cellular immunity to Candida antigen which was reversed by treatment with ketoconazole and levamisole, antedating clinical improvement.

The possibility of using liposomes as an effective drug delivery system has been studied by incorporation of two plant glycosides of varying terminal sugar residues onto the surface of liposomes and examination of their distribution in different tissues. The two glycosides, corchorusin D and asiaticoside having glucose and rhamnose respectively at the terminal ends wee selected for the purpose. The hepatic uptake of liposomes made from egg lecithin, cholesterol and dicetyl phosphate and either of the two glycosides was compared. The hepatic uptake of asiaticoside bearing liposomes was reduced, whereas that of corchorusin D bearing liposomes was enhanced and was specific for glucose. Liver perfusion followed by cell separation showed that the uptake is mostly into the non-parenchymal cells of liver. The distribution of corchorusin D bearing liposomes was maximal in the lysosomal fraction of the non-parenchymal cells. Ways of using corchorusin D bearing liposomes as delivery systems for drugs or enzymes to lysosomes have been sought.

Three cases of multiple idiopathic external resorption are presented. The condition is characterised by the absence of any widespread inflammatory response both in the gingival tissues and within the dental pulp. The only curative treatment is exodontia.

The antileishmanial antimonial drug urea stibamine was encapsulated in mannosylated and nonmannosylated liposomes and was tested against experimental leishmanial infection in hamsters. The study demonstrated that liposome encapsulation of urea stibamine enhanced its effectiveness, an effect which was greater when mannosylated liposomes were used.

The state of the lipid phase of the membrane plays a key role in the exposure of various receptors, antigens and enzymes on the membrane surface. The fluidity of membranes of Leishmania donovani promastigotes was monitored by two independent methods, i.e. influx of sterol from liposomes and removal of phospholipids by treatment with phospholipase C. The altered sterol/phospholipid ratio, in both cases, provided evidence that the activity of the functionally important membrane-bound enzyme Mg2(+)-ATPase is modulated by the state of the lipid phase of the membrane.

A characteristic electrophoretic pattern of glycosaminoglycans from fluid aspirates of the postoperative maxillary cyst has been observed. This pattern, in which hyaluronic acid and heparan sulfate are the predominant glycosaminoglycans (with lesser amounts of chondroitin-4-sulfate) may faciliate preoperative diagnosis of this lesion.

In this study we employed two approaches in attempts to explain the increased expression of I and i antigens on the membrane surface of SS erythrocytes: immunoelectron microscopy and measurements of antigen-antibody affinity. AA and SS erythrocytes were first reacted with anti-I or anti-i antisera, and then with ferritin-conjugated anti-human IgM. With both antibodies, proportions of cells labeled and ferritin-cluster density on labeled cells were greater for SS erythrocytes at a high level of significance. Studies on the temperature dependence of agglutination by anti-I provided the association constants of agglutination, which were uniformly greater for SS erythrocytes. I and i antigen determinants are carried principally on band 3, the major transmembrane protein of the erythrocyte membrane. Therefore, for SS erythrocytes, the increased I (and i) antigen density and the increased association constant of agglutination by anti-I very likely both reflect the same phenomenon: a relatively greater exposure of I (and i) antigen determinant sites at the membrane surface. Any deviation from normal at the exterior surface of the erythrocyte membrane deserves to be suspect for potential pathogenicity, because this is the cell's region of intimate contact with other elements of the circulation. In addition to enhancing susceptibility of SS erythrocytes to cold agglutinins, an altered exposure of band 3 at the membrane outer surface has the potential for accelerating recognition and removal of SS erythrocytes from the circulation by mononuclear phagocytes.

The membrane lipid fluidity of normal human erythrocytes was modified by enrichment and depletion in cholesterol, and the expression of I and SP1 antigens was assayed by quantitative hemagglutination from 4 degrees to 24 degrees C by use of a continuous flow system. Below 16 degrees--18 degrees C, cholesterol enrichment increased and cholesterol depletion decreased percent agglutination. As temperatures approached approximately 18 degrees--20 degrees C, differences in agglutination between modified and unmodified erythrocytes became insignificant despite marked differences in lipid fluidity at that temperature. Thus, fluidity changes alone cannot be responsible for the effect of membrane cholesterol on cold agglutination. In an additional study, the temperature dependence of a relative equilibrium association constant, estimated by probit analysis of percent agglutination at various antisera concentrations, was biphasic with a sharp break at 16 degrees C. Our studies are consistent with the hypothesis that I and Sp1 antigens preferentially partition into a lipid domain that forms during lateral phase separation of membrane lipid developing at low temperature. A resulting increase in antigen density would then become responsible for augmented agglutination by specific antibody.

Very low density and high density lipoproteins have been isolated from human plasma and their interaction with 1-anilin0-8-naphthalene sulfonate has been studied under different conditions of pH and added salt. Intrinsic fluorescence of bound 1-anilino-8-naphthalene sulfonate was higher for high density lipoproteins then for very low density lipoproteins, but was unaffected by salt in both systems. Binding of 1-anilino-8-naphthalene sulfonate by both these lipoproteins was saturable and was higher in the presence of added NaCl or CaCl2, Ca2+ having a greater effect than Na+ in enhancing fluorescence. The binding data were analyzed by Scatchard plots; the number of binding sites and the affinity of 1-anilino-8-naphthalene sulfonate for the site increased with increasing salt concentration. Fluorescence pH curves were similar to those published for phospholipids. From these and previous observations it is suggested that the phospholipids probably represent the major binding sites for 1-anilino-8-naphthalene sulfonate.

Cell lines derived from type II lung cells were used to study interplays of substances affecting incorporation of labeled precursors [1(-14)C]palmitate and [methyl-3H]choline into phosphatidyl choline. Ethanol stimulated markedly biosynthesis of dipalmitoyl phosphatidyl choline in cloned rabbit lung cells; the stimulating action of ethanol was reduced very much by cortisol and less by ritodrine. In the presence of 0.1 microM isoproterenol, two prostaglandins, E2 and F2alpha, caused marked depressions in the incorporation of both precursors by cell line A 549 derived from human lung adenocarcinoma. One concluded that among the agents studied, ethanol and cortisol are potent antagonists, and so were also the prostaglandins and isoproterenol.

23 cases, diagnosed as post-operative maxillary cyst, from outside Japan are described. Clinical, radiographic and histopathological features are not dissimilar to those cases reported from Japan, and various parameters have been found to be helpful in diagnosis. This lesion is more common outside Japan than previously suggested, and this is probably largely due to faulty diagnosis.

A case of malignant calcifying epithelial odontogenic tumour is reported in a 75-year-old man. Evidence of local tissue invasion and lymph-node metastasis is presented. Immunoperoxidase studies of the neoplastic cells and tumour amyloid were negative for a variety of antigens, including the epithelial markers CEA and keratin. The histological and clinical findings are discussed.