Doxorubicin-induced chronic cardiotoxicity and its protection by liposomal administration

The chronic cardiotoxicity of doxorubicin as a free drug or entrapped in positive and negative liposomes was morphologically evaluated in mice treated seven times i.v. at a dose of 4 mg/kg. Liposomes were composed of phosphatidylcholine, cholesterol, and stearylamine (positive charge) or phosphatidylserine (negative charge). Administration of free doxorubicin caused a pattern of cardiac damage characterized by loss of myofiber elements, mitochondrial damage, nuclear abnormalities, swollen and distended sarcoplasmic reticulum leading to vacuolization, and increasing myeloid body accumulation. Cardiac tissues of mice treated with doxorubicin entrapped in negatively charged liposomes demonstrated pronounced loss of filaments, enlarged mitochondria, disruptive loss of crests, and expanded nuclear membrane. However, electron microscopic examination of the cardiac muscles of mice treated with positive liposomes demonstrated a significant protection from drug-induced toxicity, with only minor loss of parallel fibrillar arrangement and myofilaments in limited focal areas. The majority of the tissue demonstrated normal vasculature and intercalation of myocytes as compared to control groups. The mean qualitative and quantitative scores of toxic lesions for free doxorubicin and entrapped in negative liposomes are 2.7 and 2.23, respectively. However, the mean score for the group of mice treated with positive liposomes is only 1.12, showing a better than 2-fold scoring protection of both the extent and severity of cardiac lesions.

Phase I trial and clinical pharmacology of 1-(2-chloroethyl)-3-(2,6-dioxo-3-piperidyl)-1-nitrosourea

1-(2-Chloroethyl)-3-(2,6-dioxo-3-piperidyl)-1-nitrosourea (NSC 95466) is a lipid-soluble nitrosourea that is presently undergoing clinical evaluation. In this Phase I study, the toxicity of this drug was examined after administration of the drug to cancer patients on 3 successive days every 6 to 8 weeks. Clinical pharmacology was studied using 1-[chloroethyl-14C](2-chloroethyl)-3-(2,6-dioxo-3-piperidyl)-1-nitrosourea. The dose-limiting toxicity was myelosuppression. The maximal tolerated dose was 105 mg/sq m, which produced a median platelet nadir of 40,000/microliter on Day 32 and a median white blood cell count nadir of 2200/microliter on Day 42. Progressive anemia was also observed. There was no evidence of acute or chronic hepatic, renal, or pulmonary damage. One patient with a metastatic hypernephroma exhibited a partial clinical remission. Plasma disappearance of the drug following bolus administration was biphasic, with an initial half-life of 18 to 25 min and a second half-life of 9 hr. Clearance of intact drug coincided largely with the initial disappearance phase of total radioactivity. Entry of radioactivity into the cerebrospinal fluid was observed. Approximately 35% of plasma radioactivity was protein bound, the major binder being albumin. Drug excretion was predominantly renal, and biliary elimination was only minor.

Will hemoperfusion be useful for cancer chemotherapeutic drug removal?

One of the major problems in clinical cancer chemotherapy is the inability to safely administer full therapeutic doses of specific drugs in the face of dysfunction of an organ system controlling that drug's metabolism and excretion. Should efficient drug removal from blood be possible following full therapeutic doses and after tumor exposure, then theoretically, even in the presence of organ dysfunction, anticancer drug toxicity may be reduced or avoided. Preliminary experiments in our laboratory have shown that adriamycin may be efficiently removed by activated charcoal from aqueous and protein solutions and blood in vivo, and that daunorubicin is removed in vitro to the same extent. However, although methotrexate is removed efficiently in vitro and extracted 50% in vivo by charcoal hemoperfusion, its overall pharmacokinetics do not appear to be altered in comparison with the alteration in pharmacokinetics of adriamycin achieved with charcoal hemoperfusion. Computer modeling has suggested that efficient adriamycin removal is achievable, and that clinical studies are warranted. For methotrexate removal, however, previous clinical studies and our own data suggest that charcoal hemoperfusion has little utility unless a highly specific sorbent for methotrexate removal can be developed.

Acute uraemic encephalopathy in tropical countries

This is a prospective study on 24 patients with chronic renal failure. Thirteen of them had evidence of acute uraemic encephalopathy. Of those 9 patients were found to have dilutional hyponatraemia, two patients severe salt and water depletion and one patient septicaemia. Hyponatraemia was associated with pulmonary oedema in 3 patients. Correction of salt and water disturbances and treatment of heart failure improved cerebral functions in 10 (77%) patients. It is therefore concluded that dilutional hyponatraemia probably leading to cerebral oedema is a reversibe major factor in the development of acute uraemic encephalopathy. This, if left uncorrected, may prove fatal especially in tropical countries.

A follow-up of vasectomy clients in rural Bangladesh

A one-year follow-up of 585 vasectomy clients sterilized at vasectomy camps in Shibpur and Shalna in rural Bangladesh showed that almost half of the clients were dissatisfied with their vasectomies. The majority of dissatisfied clients stated that their primary reasons for dissatisfaction were: (a) their ability to work had decreased and (b) they had not received all of the incentives they had been promised. However, 58% of the matched nonvasectomized controls also felt that their ability to work had decreased in the last year. Only 2%--7% of the dissatisfied clients cited decreased sexual performance as their primary reason for dissatisfaction. Satisfied vasectomy clients most frequently cited: (a) the permanence of this method of birth control and (b) the incentives they received as their reasons for satisfaction.

Dissolution and absorption of the antineoplastic agent ellipticine

Ellipticine, a poorly water-soluble alkaloid, is active in several experimental tumor systems. Marked solubility increases were produced by polyvinylpyrrolidone of varying molecular weights (10,000--160,000) and were optimal (approximately 13 mg/ml at 25 degrees) with polyvinylpyrrolidone mol. wt 10,000. Dissolution of ellipticine--polyvinylpyrrlidone (1:22 w/w) tablets in simulated gastric juice was superior to that of ellipticine hydrochloride polymers without affecting maximum dissolution at 37 degrees. Physiological disposition of ellipticine--polyvinylpyrrolidone was compared with that of the hydrochloride salt and ellipticine in suspension following oral administration at 250 mg/kg in fasted mice. In comparison to the suspension, ellipticine tissue levels were about threefold higher with polyvinylpyrrolidone or hydrochloride preparations. Antitumor activity of the three preparations was evaluated intraperitonneally and orally versus L-1210 leukemia. The optimal dose of ellipticine--polyvinylpyrrolidone and ellipticine hydrochloride was lower than that of the suspension and suggested improved absorption.

Evaluation of some pharmaceutical aspects of intrathecal methotrexate sodium, cytarabine and hydrocortisone sodium succinate

Methotrexate sodium, cytarabine and hydrocortisone sodium succinate were evaluated in three vehicles, Sodium Chloride Injection, USP, Lactated Ringer's Injection, USP, and Elliott's B solution, an artificial cerebrospinal fluid (CSF). Osmolarity values of all drug solutions studied were within 10% of normal human. No vehicle-related alterations in the stability of methotrexate or cytarabine were detected under simulated use conditions. However, the degradation of hydrocortisone sodium succinate was faster in Elliott's B solution than in the other vehicles. Principal differences among the vehicles involved electrolyte content, pH and buffer capacity. Elliott's B solution is similar to CSF in electrolyte composition and buffer capacity, and was the only vehicle to maintain the pH of dilute methotrexate and cytarabine solutions between 7.2 and 7.8. The significance of these in vitro data await a careful clinical study.

Amoebic liver abscess and clinical experiences with tinidazole in Bangladesh

35 cases of amoebic liver abscess have been studied and their clinical diagnostic features analyzed. The diagnosis was based on WHO criteria of enlarged tender liver, leucocytosis and aspiration of typical anchovy sauce pus from the abscess. The authors have however, suggested major and minor diagnostic criteria for the condition. These cases were all treated with new nitroimidazole derivative Tinidazole in a single dose of 2 gm daily for consecutive 2 or 3 days. All the cases were followed up for at least 2 months. 100 per cent cure rate was observed. However, in 7 cases the dosage had to be repeated. Minor side effects were noted. The liver function tests and blood chemistry done pretreatment and post-treatment did not show any drug related toxicity.

Search for the presence of lectin-binding sites on Toxoplasma gondii

Evidence for the presence of carbohydrate on the surface membrane of Toxoplasma gondii trophozoites and on the cell wall of toxoplasma brain cysts was sought by fluorescent lectin staining. Using FITC-conjugated preparations of Concanavalin A (Con A), wheat germ agglutinin (WGA), or soy bean agglutinin (SBA), we have failed to obtain evidence for the binding of these lectins on the surface of T. gondii trophozoites. In contrast, the three test lectins bound effectively and specifically to the wall of toxoplasma brain cysts. Prefixation of cysts with glutaraldehyde or brief trypsinization of cysts did not affect the intensity of cyst wall fluorescence when stained with FITC-conjugated Con A, SBA, or WGA. The results are interpreted to indicate that whereas exposed Con A, SBA, and WGA binding sites are associated with the wall of toxoplasma brain cysts, such lectin-binding saccharide residues are not present on the surface of trophozoites in exposed or reactive form.

Iron-deficiency anaemia in pregnancy: (biochemical investigations of iron-deficiency and nutritional status)

Biochemical investigations on iron deficiency and nutritional status were carried out in a group of 130 women in the second or third trimesters of pregnancy and in 42 control non-pregnant women. The important findings were: 1. Anaemia was present in 46.1% of pregnant women in comparison with 19% in non-pregnant women. It was found to be more prevalent in the third trimester of pregnancy. 2. Iron deficiency with and without anaemia, as judged from serum transferrin saturation (%) was evident in 59.2% of pregnant women with an incidence of 70.3% in the third trimester of pregnancy. 3. Serum albumin, gamma globulin and A/G ratio were found to be decreased in pregnancy whereas serum levels of alpha-2 and beta globulins were elevated. The results have been discussed.

T cell deficiency in patients with autoimmune hemolytic anemia ('warm type')

19 patients with chronic 'warm type' autoimmune hemolytic anemia were studied for abnormalities of cellular immune reactions. Evidence was obtained for a reduction of rosette-forming cells (RFC). Lymphocytotoxic antibodies were present in only 8 patients and correlated, with only one exception, with a reduced number of RFC. No significant deviation from normal ranges of the three major immunoglobulin classes in the patients' sera were found. C3 and C4 complement components were also, with one exception, within normal limits. In 18 of 19 patients no apparent association existed between the type or the amount of autoantibodies and/or complement components fixed on red cells and the levels of the respective immunoglobulins or complement in the sera.