Oral Administration Of Chloroquine Research Articles

Potential Effect of Chloroquine in Modulating Hyperglycemia and PTEN Receptor Linked Dyslipidemia on Alloxan-induced Diabetic Mice

Background: Diabetes mellitus is a life-threatening disease associated with worsening of glycemic control, progressive metabolic dysfunctions and disruption of the Phosphatase and Tensin Homolog (PTEN) receptor. Purpose: To evaluate the effect of chloroquine on blood glucose level and lipid profile of alloxan-induced diabetic mice and to observe its interaction with PTEN, a negative regulator of insulin signaling pathway. Methodology: Thirty mice were used for the experiment. A group (n = 5) was kept as healthy control while the others were pre-treated with 140 mg/kg of alloxan monohydrate in distilled water. The alloxan-induced diabetic mice were randomly divided into four groups: diabetic model control group, 60 mg/kg chloroquine, 120 mg/kg chloroquine, and 10 mg/kg glibenclamide treatment groups respectively. Treatment was done once daily for seven days and the blood glucose level was investigated acutely and then daily throughout the experimental period. A molecular docking study was also conducted to evaluate the interaction of chloroquine with PTEN using PYRX software, while an automated COBAS C 311 machine was used to analyze the lipid profile after the treatment period. Results: Oral administration of chloroquine gradually and significantly lowered the raised blood glucose level in a time- and dose-dependent manner. A repeated study with 120 mg/kg of chloroquine revealed a decline in blood sugar from 221.5 ± 3.6 on day 1 to 85.5 ± 2.4 on day 7 in comparison to glibenclamide, whose sugar level was reduced to 75.5 ± 3.7 at the end of day 7. The docking study revealed a non-competitive inhibition with an inhibition score of -6.1 in comparison to metformin, which had a score of -4.4, and glibenclamide, which had a score of -9.0. This interaction resulted in a conformational change of the receptor, hence, enhancing glucose uptake and reducing the raised hyperglycemia. Treatment with chloroquine was also observed to reduce the total cholesterol and triglyceride levels from 162 in the model group to 144 and 141 to 116 mmol/L, respectively. The levels of low-density lipoprotein cholesterol (LDL-C) and very low-density lipoprotein (VLDL) following treatment with chloroquine were not statistically different from the non-diabetic healthy mice. These values were very similar to those obtained with glibenclamide-treated diabetic mice. Conclusion: From the results, chloroquine possesses potent antidiabetic properties and can improve dyslipidemia imposed by hyperglycemia probably owing to its inhibition of PTEN, a negative regulator of insulin resistance.

DOES ORAL CHLOROQUINE AFFECT THE HIPPOCAMPUS IN RATS? A CLUE TO CHLOROQUINE INDUCED NEUROPSYCHIATRIC ADVERSE EFFECTS

Background: Chloroquine is widely used in medicine. The main indication for its usage is treatment of malaria. Reportsabout psychiatric side effects of chloroquine are rare. However, the list of recorded chloroquine induced neuropsychiatricdisorders shows wide range of symptoms. Aim of the work: In this study, the effect of oral chloroquine on the hippocampus of rats was assessed. Material and methods: Twenty seven male adult albino rats were randomly divided into four groups. Group I (control group): nine rats were divided into I-a and I-b subgroups. Group II (chloroquine for two weeks): six rats received 4ml of distilled water solution/day containing chloroquine in a dose of 80 mg/kg bwvia oral gavage for two weeks. Group III (chloroquine for three weeks): six rats received chloroquine as in group II for three weeks. Group IV (chloroquine for four weeks): six rats received chloroquine as in group II for four weeks. After sacrifice, the hippocampi were retrieved, fixed, and processed for paraffin sections. H&E and Bielschowsky silver stains were applied and immunehistochemical staining for GFAP was performed to examine the distribution of astrocytes. Results: Examination of different regions of the hippocampal formation revealed dark, shrunken cells, with pyknotic nuclei and pericellular spaces in all treated groups. Neurofibrillary tangles were also seen in some stained sections. Moreover, an increase in the density of astrocytes was also observed. Morphometrically, there was a decrease in the thickness of both pyramidal and granular layers of cornu ammonis and dentate gyrus respectively in all treated groups as compared with control group. All these changes appeared in group II, and were clearer in both groups III and IV. Conclusion: It was concluded that oral administration of chloroquine caused duration dependent neuronal damage in the hippocampus of rats giving a possible explanation for chloroquine induced neuropsychiatric adverse effects.

The Antimalarial Chloroquine Reduces the Burden of Persistent Atrial Fibrillation.

In clinical practice, reducing the burden of persistent atrial fibrillation by pharmacological means is challenging. We explored if blocking the background and the acetylcholine-activated inward rectifier potassium currents (IK1 and IKACh) could be antiarrhythmic in persistent atrial fibrillation. We thus tested the hypothesis that blocking IK1 and IKACh with chloroquine decreases the burden of persistent atrial fibrillation. We used patch clamp to determine the IC50 of IK1 and IKACh block by chloroquine and molecular modeling to simulate the interaction between chloroquine and Kir2.1 and Kir3.1, the molecular correlates of IK1 and IKACh. We then tested, as a proof of concept, if oral chloroquine administration to a patient with persistent atrial fibrillation can decrease the arrhythmia burden. We also simulated the effects of chloroquine in a 3D model of human atria with persistent atrial fibrillation. In patch clamp the IC50 of IK1 block by chloroquine was similar to that of IKACh. A 14-day regimen of oral chloroquine significantly decreased the burden of persistent atrial fibrillation in a patient. Mathematical simulations of persistent atrial fibrillation in a 3D model of human atria suggested that chloroquine prolonged the action potential duration, leading to failure of reentrant excitation, and the subsequent termination of the arrhythmia. The combined block of IK1 and IKACh can be a targeted therapeutic strategy for persistent atrial fibrillation.

Autophagy in the Central Nervous System and Effects of Chloroquine in Mucopolysaccharidosis Type II Mice.

Mucopolysaccharidosis type II (MPS II) is a rare lysosomal storage disease (LSD) involving a genetic error in iduronic acid-2-sulfatase (IDS) metabolism that leads to accumulation of glycosaminoglycans within intracellular lysosomes. The primary treatment for MPS II, enzyme replacement therapy, is not effective for central nervous system (CNS) symptoms, such as intellectual disability, because the drugs do not cross the blood–brain barrier. Recently, autophagy has been associated with LSDs. In this study, we examined the morphologic relationship between neuronal damage and autophagy in IDS knockout mice using antibodies against subunit c of mitochondrial adenosine triphosphate (ATP) synthetase and p62. Immunohistological changes suggesting autophagy, such as vacuolation, were observed in neurons, microglia, and pericytes throughout the CNS, and the numbers increased over postnatal development. Oral administration of chloroquine, which inhibits autophagy, did not suppress damage to microglia and pericytes, but greatly reduced neuronal vacuolation and eliminated neuronal cells with abnormal inclusions. Thus, decreasing autophagy appears to prevent neuronal degeneration. These results suggest that an autophagy modulator could be used in addition to conventional enzyme replacement therapy to preserve the CNS in patients with MPS II.

Abstract 3538: Effects of oral chloroquine administration on a preclinical mouse model of PTEN/p53-deficient prostate cancer

Abstract Autophagy is cellular process that can promote tumor survival during periods of metabolic and therapeutic stress. Inhibition of autophagy can promote senescence resulting in decreased tumor growth. Genetic alterations of PTEN and p53 are frequently present in advanced human prostate cancer and are associated with poor prognosis. In mouse models, the inactivation of PTEN leads to the development of prostate tumors that progress slowly, in part due to the induction of PTEN-(loss)-induced cellular senescence. Concomitant inactivation of both PTEN and P53 in prostate leads to the development of an aggressive cancer phenotype that can overcome PTEN-(loss)-induced cellular senescence and is characterized with accelerated growth, metastatic development and decreased survival. Published findings show that in some cancer models, the effects of autophagy inhibition are dependent on p53 status. In this study we assessed the effects of pharmacological inhibition of autophagy with chloroquine (CQ) on the growth and progression of mouse prostate tumors driven by the concomitant inactivation of PTEN and p53. CQ is a lysosomotropic agent that has widely used to impede autophagy and inhibit the growth of human tumor cells in vitro and in vivo. Genetically engineered mice with the conditional inactivation of PTEN and p53 were used to evaluate the antitumor effects and therapeutic benefit of CQ in a drug intervention model of prostate cancer. Twenty-seven-week-old PTEN/p53 double knockout mice bearing prostate tumors were randomized to control and oral CQ (100 mg/kg in drinking water) treatment groups. Progression-free survival was 145 days versus 161 days (P = 0.703) for control and CQ treated mice, respectively. Median overall survival was 170 days versus 147 days (P = 0.523) for control and CQ treated mice, respectively. Tumor burden assed by the median genitourinary tract weight was 2.42 grams versus 2.19 grams (P = 0.645) for control and CQ treated mice, respectively. Our molecular assays revealed that CQ failed to consistently inhibit autophagy in tumors at the present dose. Overall, our findings show that CQ alone did not provide treatment benefit in mouse prostate cancer with loss of p53. Citation Format: Marco A. De Velasco, Koichi Sugimoto, Yurie Kura, Yuji Hatanaka, Yutaka Yamamoto, Takashi Oki, Kazuhiro Yoshimura, Masahiro Nozawa, Kazuhiro Yoshikawa, Kazuto Nishio, Hirotsugu Uemura. Effects of oral chloroquine administration on a preclinical mouse model of PTEN/p53-deficient prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3538.

Intralesional Versus Oral Chloroquine in Cutaneous Leishmaniasis: Comparison of Outcome, Duration of Treatment and Total Dose of Drug.

To compare intralesional versus oral chloroquine in cutaneous leishmaniasis and determine the cure rate, duration of treatment, and total dose of drug. Randomized controlled study. Department of Dermatology, Sheikh Zayed Medical College/Hospital, Rahim Yar Khan, from November 2013 to June 2014. Consecutive 86 patients of cutaneous leishmaniasis, with single to multiple lesions of various sizes were enrolled and divided randomly into group Aand B for the purpose of intralesional and oral chloroquine administration, respectively to compare the effect of the two routes on duration of treatment and total dose of the drug. SPSS version 16 was used for data analysis after data entry into it. Quantitative variables like, duration, cost and total dose of treatment were calculated as mean and standard deviation and compared by using T-test. P-value of less than 0.05 was taken as significant. Cure rate was 100% in both groups towards the end of treatment. Mean duration of treatment was 9.17 ±3 weeks in intralesional (A) group as against 11.37 ±3 weeks in oral (B) group (p = 0.0028). Mean total dose of the drug given to each patient in group Awas 5.8 ±0.5 gm and in group B, it was 19.2 ±1.5 gm, which is significantly higher (p < 0.001). The total cost of treatment in group Awas Rs. 90 ±8 and in group B it was Rs. 91 ±1 (p=0.446). Duration of treatment is significantly shorter and total dose is lesser with intralesional compared to oral chloroquine in treatment of cutaneous leishmaniasis.

Anti-rheumatic activity of chloroquine-SLN gel on wistar rats using complete freund's adjuvant (CFA) model

AimWe tested the utility of topical application of Chloroquine-Solid Lipid Nanoparticle loaded gel against rheumatoid arthritis using Complete Freund's adjuvant (CFA) induced arthritic model. MethodsChloroquine loaded solid lipid nanoparticle (SLN) was prepared using probe sonication method. Briefly, the drug was solubilized into melted compritol which was further emulsified using aqueous medium followed by subjection to ultra-sonication to reduce the globule size. Further cooling the nano sized emulsion rendered SLN which was incorporated into a gel matrix. Ex vivo permeability study of the same was also performed using Franz diffusion cell, taking chloroquine phosphate gel as standard. Pharmacodynamics study (Radiographic & histopathology analysis) was performed to evaluate the efficacy of the formulation in arthritis induced rats. ResultsSLN with a particle size of 113.75 nm and entrapment efficiency of 97.23% were obtained. It was found from ex-vivo permeation study that chloroquine-SLN loaded gel shows maximum retention in skin as compared to chloroquine phosphate gel. Radiographic and histopathology studies of the arthritic rats treated with Chloroquine SLN gel revealed lesser extent of bone and cartilage degradation as compared to those treated with chloroquine phosphate gel. ConclusionThe chloroquine-SLN loaded gel had greater protective potential over chloroquine phosphate gel. It may be possible to target the affected site locally and overcome the problems of gastrointestinal as well as dose dependent systemic side effects associated with oral administration of chloroquine.

Is Chloroquine Making a Comeback?

Is Chloroquine Making a Comeback?

Therapeutic responses ofPlasmodium vivaxandP. falciparumto chloroquine, in an area of western India whereP. vivaxpredominates

In 2003-2005, following an increase in the local incidence of human malaria, the therapeutic efficacy of chloroquine (CQ) in the treatment of Plasmodium vivax and P. falciparum malaria was evaluated in the Anand district of Gujarat state, in western India. After oral administration of CQ, clinical and parasitological responses were measured over a follow-up period of 28 days, following the standard protocol of the World Health Organization. Most of the recurrent infections were checked, by genotyping, to see whether they were the result of treatment failure or re-infection during the follow-up. At the primary health centre (PHC) in Deva, all 57 P. vivax cases included in the study responded to CQ within 3 days. At the Pansora PHC, however, only 59 [90.8%, with a 95% confidence interval (CI) of 83.7%-97.8%] of the 65 P. vivax cases appeared to respond completely, recurrent infections being observed in the other six cases (9.2%; CI=2.2%-16.3%). Of the four recurrent infections checked by genotyping, however, only two appeared to be the result of true treatment failure. Twenty-seven (81.8%; CI=67.2%-94.4%) of the 33 P. falciparum cases who were enrolled in the study, all from Pansora PHC also showed apparent treatment failure, with one early failure, 17 late clinical failures and nine late parasitological failures. All 23 P. falciparum cases that showed apparent treatment failure and were investigated by genotyping appeared to be true cases of failure, none showing any evidence of re-infection during follow-up. The mean parasite-clearance times for those infected with P. falciparum, both those considered CQ-sensitive and the treatment failures, exceeded 2 days. These results indicate the presence of CQ-resistant P. vivax and P. falciparum in Anand district. The high frequency of CQ failure against P. falciparum observed in this study led to a change in the drug policy at the Pansora PHC, with artemisinin-based combination therapy now being used for the first-line treatment of P. falciparum malaria. Chloroquine remains the recommended first-line treatment for P. vivax infections in the area but the treatment failure seen in at least two P. vivax cases indicates a need for further monitoring of the therapeutic efficacy of CQ against such infections, in central Gujarat and elsewhere.

Human Crimean-Congo Hemorrhagic Fever, Sénégal

To the Editor: Crimean-Congo hemorrhagic fever (CCHF) virus, genus Nairovirus, family Bunyviridae, is transmitted to mammals and birds by ticks. Hyalomma ticks, the primary vectors in CCHF transmission, are widespread throughout Europe, Asia, the Middle East, and Africa; evidence of CCHF virus has been found in all these regions. CCHF in humans is an acute viral disease that is transmitted by the bite of infected ticks, direct contact with blood or infected tissues from viremic animals, and direct contact with the blood or secretions of an infected person (1). On January 26, 2003, a 22-year-old shepherd was treated at a health post in the Popenguine District, 60 km south of Dakar, Senegal; he reported fever, epistaxis, arthralgia, myalgia of the lower limbs, and dark urine for the past 2 days. Without biologic confirmation of the infection, he was treated for malaria with two intravenous injections of quinine, followed by oral administration of chloroquine. On January 31, the patient had a temperature of 39°C, conjunctival jaundice, bleeding gums, and was vomiting blood. He was seen again at the health post and was given antimicrobial drugs, intravenous quinine, and vitamin K; the next day, the bleeding stopped and the fever subsided. A serum sample was sent to the World Health Organization Collaborative Centre for Arboviruses and Viral Hemorrhagic Fevers at the Institut Pasteur, Dakar. Tests for anti-CCHF specific immunoglobulin (Ig) M antibody by enzyme-linked immunosorbent assay (ELISA) were positive, and CCHF virus by isolation on cell cultures (AP61 and Vero cells) and reverse transcriptase-polymerase chain reaction (RT-PCR) were negative. From January 31 to February 10, the IgM titer increased from 1/3,200 to >1/12,800 and IgG titer increased from 1/200 to 1/6,400. Examination of the patient on February 10 showed he had recovered without sequelae, and no trace of tick bites was found. The patient stated that he had not traveled, noticed any tick bites, slaughtered any animals, or been in contact with people with fever for several weeks before his illness. He lived in close proximity to goats and cattle, but no blood samples were taken from these animals. Although no ticks were found on nearby goats, 10 Amblyomma and Hyalomma ticks were collected from three cattle. Ticks were negative for CCHF virus isolation on suckling mice and RT-PCR amplification. No other case of fever accompanied by hemorrhage was reported in the area, and none of the patient's 14 close contacts became ill. Of the four close contacts from whom blood samples were taken, analyses for IgM and IgG antibodies against CCHF virus were negative by ELISA. While no clinical case of CCHF has ever been reported in Senegal, studies dating from 1969 indicate that CCHF virus had been found in various locations in the country (2,3). In the village of Bandia, in the same district where the reported case was observed, a study conducted from 1986 to 1988 showed a prevalence of anti-CCHF IgG of 3.2% in the human population (4). Another study, conducted in the same area from 1989 to 1992, showed seroconversions for several ruminants and isolated the virus from ticks (5). During CCHF outbreaks, an average of 30% of people who had the disease died (case-fatality ratio). It is often discovered during nosocomial outbreaks, as was the case in Mauritania, a country on Senegal's northern border, in 2003 (P. Nabeth, unpub. data). To prevent outbreaks of CCHF, public awareness campaigns aimed at the populations most at risk—livestock farmers, butchers, and health personnel—must be conducted, and the epidemiologic alert systems must be strengthened. In addition, conditions that enhance maintenance of the virus in nature and its transmission to humans must be better understood so adequate control measures can be developed.

Protective effect of alpha-lipoic acid against chloroquine-induced hepatotoxicity in rats.

Oral administration of a-lipoic acid, a metavitamin, was investigated for its possible hepatoprotective effect in Wistar rats against chloroquine-induced toxicity. Rats were treated orally with alpha-lipoic acid (10, 30 and 100 mg x kg(-1) day(-1)) for 7 days before a single oral administration of chloroquine (970 mg x kg(-1) day(-1)) and alpha-lipoic acid treatment was continued for three more days. The increased level of serum enzymes (aspartate transaminase, alanine transaminase and alkaline phosphatase), bilirubin, lipids and plasma thiobarbituric acid-reactive substances (TBARS) and hydroperoxides observed in rats treated with chloroquine were very much reduced in rats treated with alpha-lipoic acid plus chloroquine. A significant decrease in plasma antioxidants such as reduced glutathione (GSH), vitamin C and vitamin E were observed in chloroquine-treated rats when compared with control rats. Administration of alpha-lipoic acid significantly improved the levels of plasma antioxidants GSH, vitamin C and vitamin E in chloroquine-treated rats. In the case of 100 mg x kg(-1) day(-1) the effect was highly significant compared with the other doses (10 and 30 mg x kg(-1) day(-1)). The results of the study revealed that alpha-lipoic acid could offer protection against chloroquine-induced hepatotoxicity. alpha-Lipoic acid had a better protective effect when compared with silymarin, a reference drug.

Attenuation of Chloroquine‐Induced Renal Damage by α‐Lipoic Acid: Possible Antioxidant Mechanism

The toxic effect of chloroquine (CQ) has been attributed to oxidative stress with the consequences of lipid peroxidation. This study investigates the effects of α‐lipoic acid (LA) on CQ‐induced nephrotoxicity in rats. A single oral administration of CQ (970 mg/kg)‐induced nephrotoxicity, manifested biochemically by a significant increase in serum creatinine and blood urea nitrogen concentrations. In addition, renal tissue from CQ‐treated rats showed a significant increase in lipid peroxides measured as thiobarbituric acid reactive substances and hydroperoxides, along with significant decrease in nonenzymic antioxidants (vitamin C, vitamin E, and reduced glutathione) and enzymic antioxidants (superoxide dismutase, catalase, glutathione peroxidase, and glutathione‐S‐transferase) levels. Oral administration of LA (10, 30, or 100 mg/kg) in different doses for 10 days produced a significant protection against nephrotoxicity induced by CQ. Treatment with LA markedly reduced the elevated lipid peroxidation, restored the depleted renal antioxidant defense system. LA at 100 mg /kg was effective when compared with other doses (10 and 30 mg/kg). This was accompanied by the histopathological observations in kidney tissue. The results suggest that LA ameliorate the lipid peroxidation and the loss of cellular antioxidants, thereby protecting the CQ‐induced oxidative damage in kidney.

Effect of grapefruit juice on plasma chloroquine kinetics in mice.

1. It is known that grapefruit juice (GFJ) may interact with drugs concomitantly administered by inhibiting first-pass metabolism during the intestinal absorption phase. However, its interaction with chloroquine has not been studied previously. 2. Grapefruit juice (4 mL/kg) was given orally to mice 1 h prior to oral administration of chloroquine (100 mg/kg) and the concentration of the latter drug was measured fluorometrically in the plasma 0, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12, 18 and 24 h after its administration. 3. The mean (+/-SEM) of area under the curve values after administration of water +/- control) and GFJ were 5.34 +/- 0.38 and 7.01 +/- 0.66 mg.h/L, respectively. The corresponding mean C(max) values were 763.4 +/- 39.1 and 859.2 +/- 45.2 mg/L and the corresponding T(max) values (median) were 2.65 and 2.95 h. 4. The results suggest that GFJ coingestion increased the plasma concentration of chloroquine and altered some kinetic parameters of chloroquine. The clinical significance of this interaction in patients with malaria needs to be investigated.

Effect of Chloroquine on Rat Liver Microsomes.

Alterations in liver microsomal drug-metabolizing enzymes and phospholipids following oral administration of chloroquine to rats for 14 days were investigated. An increase in cytochrome P450 and cytochrome b5 contents and an increase in the activities of NADPH cytochrome c reductase and NADH microsomal cytochrome reductase were observed. A decrease in cholesterol and an increase in phospholipids were noted in the microsomal membranes, which altered the membrane fluidity, which may be of importance in controlling different membrane functions. The increase in different fractions of microsomal phospholipid is probably due to an increased incorporation of acetate into phospholipids.

The Effects of Oral Chloroquine Administration on Kidney Function

The effects of 3 consecutive days of oral chloroquine (1 mg/100 g body weight) on kidney function and blood pressure were studied in male Sprague-Dawley rats that were challenged with hypotonic saline infusion 24 h after the last chloroquine administration. The rats were anesthetized with Inactin [5 ethyl-5-(1'-methylpropyl)-2-thiobarbiturate, Byk Gulden] and continuously infused with 0.077 M NaCl for 8 h; urine flow and electrolyte excretion rates were monitored during the last 5 h. Blood pressure and glomerular filtration rates were also measured. Kidney function was compromised in chloroquine-treated rats, which retained significantly more of the infused Na+ and Cl- by comparison to control-vehicle-treated rats. Throughout the experimental period, chloroquine-treated rats exhibited low blood pressure (80 mm Hg vs. 127 mm Hg) which was associated with low glomerular filtration rate. The plasma aldosterone concentrations were significantly (p < 0.01) elevated in rats pretreated with chloroquine at the end of the 8-h infusion of hypotonic saline, but corticosterone levels were significantly (p < 0.01) lower in the treated rats. It is concluded that chloroquine administration impairs kidney function, resulting in inappropriate Na+ and Cl- retention. This effect is likely to be mediated via chloroquine-induced increases in plasma aldosterone concentration and lowering of GFR.

Status of oxidative stress and antioxidant defences during Plasmodivm knowlesi infection and chloroquine treatment in Macaca mulatta

Plasmodium knowlesi (a simian malarial parasite) infection resulted in elevation of hepatic oxidative stress in monkeys. Further, the antioxidant defence system of the host was also noticeably affected. The infected monkeys showed a marked increase in the levels of superoxide (O − 2), lipid peroxidation (LPO), glutathione (GSH) and xanthine oxidase (XO), and decreased levels of superoxide dismutase (SOD) and catalase. Oral administration of chloroquine (20 mg kg body wt −1 for 3 days) to infected monkeys caused recovery trends in oxidative stress and antioxidant defences to almost normal a week after cessation of drug treatment.

Status of hepatic heme and heme oxygenase during Plasmodium yoelii nigeriensis infection in mice

Plasmodium yoelii nigeriensis infection in albino mice caused a significant increase in hepatic heme level, the increase being concomitant with a rise in parasitemia. This elevated heme was found to be associated with all the subcellular fractions except the cytosol, where its content remained unaltered. Activity of heme oxygenase, the key enzyme responsible for catabolism of heme, also increased progressively with rise in parasitemia. Treatment of normal mice with cobalt chloride [60 mg (kg body wt) −1; subcutaneously] brought about a 150% increase in the level of heme oxygenase; similar treatment of infected mice at low parasitemia could induce the enzyme activity while at high parasitemia the enzymic activity remained unaltered as compared to untreated infected mice. In spite of an increased level of heme oxygenase in the cobalt-treated mice, the level of heme did not show any noticeable change. Oral administration of chloroquine [64 mg (kg body wt) −1 × 4 days] brought about a 56% reduction in the level of heme oxygenase of normal animals but there was no change in infected animals when compared with the corresponding untreated infected mice. However, the amount of chloroquine present in livers of normal and infected animals was not significantly different.

Cobalamin release from intrinsic factor and transfer to transcobalamin II within the rat enterocyte

To ascertain the mechanism of release of cobalamin (Cbl) from intrinsic factor (IF) and subsequent formation of transcobalamin II (TC-II)-Cbl complex, we studied the intracellular distribution of 57Co-labeled Cbl after its uptake in suckling and adult rats. The amount of Cbl bound to IF, to the IF-Cbl receptor via IF, and to TC-II was determined by immunoprecipitation with monospecific antisera raised to these proteins. IF-Cbl receptor activity was found to be very low in suckling rats up to 12 days after birth. Oral administration of leupeptin in amounts known to alter protein turnover had no effect on the release of Cbl from IF nor did it inhibit the formation of the TC-II-Cbl complex in either adult or suckling animals. However, oral administration of chloroquine resulted in a transient increase in the intestinal concentration of Cbl in both adult and suckling rats and in total inhibition of Cbl released from IF in adults rats. Chloroquine prevented completely the transfer of Cbl to TC-II in adult rats and inhibited the transfer by 50% in suckling rats. These data demonstrate that in adult mucosa utilizing receptor-mediated endocytosis, Cbl is transferred from IF to TC-II. This transfer does not require the IF-Cbl receptor, as it occurs in suckling rats. Finally, transfer of Cbl to TC-II is decreased by a drug that alters vesicular pH. Because Cbl can be released at acid pH from IF, it is proposed that release of Cbl from IF and its transfer to TC-II occurs in an acidic vesicle.

Spontaneous storage-like disease in a rabbit.

Inborn errors of metabolism in lysosomal function result in storage of substrate within cells.’ Naturally occurring storage diseases have not been reported in rabbits. Storage-like conditions, however, have been induced experimentally in rabbits through oral administration of chloroquine and intravenous administration of polyvinyl alcohol, polyvinyl acetate, or poly~tylol.~.~ A 22-week-old male New Zealand albino rabbit was necropsied after use as a control in a 28-day percutaneous toxicity study. No significant gross or clinicopathologic alterations were noted before or at the time of necropsy. Histologically, the liver, intestine, adrenal gland, lymph node, and pancreas contained large cells with expanded, foamy cytoplasm. These cells had distinct cytoplasmic borders and occurred singularly or as multicellular aggregates. They had oval, centrally located nuclei and large amounts of granular to vacuolated eosinophilic cytoplasm. In the liver, vacuolated cells were in aggregates in and around portal tracts within the margins of the limiting plate (Fig. 1). Dense aggregates of similar cells were in the lamina propria and submucosa of the small intestine (Fig. 2). In the exocrine pancreas, the vacuolated cells also were found in aggregates surrounding excretory ducts. Adrenal glands and lymph nodes contained vacuolated cells distributed singularly throughout the parenchyma. All other organs and tissues (including spleen, bone marrow, and brain) were unaffected. Histochemically, cytoplasm of the affected cells contained small amounts of carbohydrate, but no fat, or sphingomyelin as determined with periodic acid-Schiff, oil red 0, and Nile blue stains, respectively. Gomori’s methenamine-silver and Kinyoun’s acid fast stains revealed no organisms. Ultrastructurally, the vacuolated cells in the liver and intestine contained multiple, compartmentalized, empty vacuoles (Fig. 3). Based on the history of laboratory confinement, with no exposure to xenobiotics, it was concluded that these alterations were part of a rare, spontaneously-occurring disease. The presence of vacuolated cells in multiple organs without evidence of inflammation, necrosis, or infectious organisms suggested that we were dealing with a storage disease. Fur-

Adsorption, distribution and elimination of chloroquine in the presence of aspirin when administered into rabbits

1. 1. The absorption, distribution and elimination of chloroquine were studied in rabbits upon oral administration of chloroquine with aspirin. 2. 2. The time-lag, half-life of absorption and absorption rate constant obtained in both cases were significantly different ( P < 0.01) whereas the half-life of elimination and the elimination rate constant were not significantly different ( P > 0.01). 3. 3. The results showed that absorption was delayed when aspirin was simultaneously administered with chloroquine but the distribution and elimination of chloroquine were not affected by the presence of aspirin.