In vitro effect of indomethacin on polymorphonuclear leukocyte function in preterm infants

Random motility and chemotaxis of polymorphonuclear leukocytes (PMN) was evaluated after in vitro exposure to 0, 300, 600, and 900 ng/mL (0.84, 1.68, and 2.52 mumol/L) of indomethacin. PMN were obtained from cord blood of 22 preterm infants of less than 37 wk gestation. For comparison, PMN were obtained from cord blood of seven healthy full-term infants and from venous blood of 10 normal adults. In preterm infants, a significant decrease of random motility and chemotaxis of PMN was noted at all three drug concentrations; impairment of PMN function was dose dependent in the three groups (p < 0.0001), with the greatest effect seen at 900 ng/mL (2.52 mumol/L). Significant impairment of random motility was noted in full-term infants when compared with adults at all indomethacin concentrations and in chemotaxis at 300 and 600 ng/mL (0.84 and 1.68 mumol/L). The study indicates that indomethacin has an adverse effect on PMN random motility and chemotaxis, which is more pronounced in preterm infants.

Gait in relation to ageing and idiopathic parkinsonism

Distance/time measures of gait in 105 sufferers from idiopathic Parkinsonism, who were able to walk unaided, and 144 healthy controls were examined systematically. Those sufferers with overt fluctuations in control were assessed during their "therapeutic window". Free walking speed was lower for a given cadence in the sufferers, but reached a plateau whilst cadence could still be increased. Age, cognitive function and the range of passive hip flexion were important determinants of gait in them. Even minor degrees of cognitive impairment were associated with reduced free walking speed in sufferers: it appears unwise that they were prescribed more sedatives than the controls. The potential benefit of physiotherapy in maintaining joint flexibility was noted. The deficits in speed of individual sufferers, and hence the estimated potential for prophylaxis and treatment, were unrelated to age at presentation. There was no evidence for a limited period of responsiveness to levodopa therapy in this cross-sectional study.

Thermogenesis after surgery: effect of perioperative heat conservation and epidural anesthesia

Body temperature, respiratory gas exchange, and plasma catecholamines were determined before and after surgery in three groups [control (C), warmed (W), and epidural (E) who received local anesthetic at T4-S5 dermatomes during and for 24 h after surgery] of patients undergoing colonic surgery under general anesthesia. At the end of surgery, group W were nursed in an ambient temperature of 28-30 degrees C, whereas the others were at 20-23 degrees C for a period of 24 h. Core (Tc) and dorsal hand temperature decreased during surgery in both C and E (P less than 0.05) but not in W. After surgery, Tc increased similarly in C and E and by a smaller amount in W. Plasma catecholamine concentrations increased significantly in C and W but not in E (P less than 0.001), with the greatest response occurring in C. Postoperative oxygen consumption and carbon dioxide production exceeded preoperative values (P less than 0.01) in C but not in W or E. After surgery, plasma albumin fell and C-reactive protein increased similarly in all three groups. Thus body heat conservation or epidural blockade attenuates or abolishes the rise in plasma catecholamines and oxygen consumption postoperatively but does not prevent the increase in Tc or the acute phase protein response.

Portal-systemic shunting and the disruption of circadian locomotor activity in the rat

To determine if the extent of portal-systemic shunting (PSS) influences the disruption of circadian function in chronic liver disease, locomotor activity was examined in two rat models with varying degrees of PSS, i.e., portal vein ligation (PVL) and end-to-side portacaval anastomosis (PCA). Animals were housed in individual activity cages under conditions of 12 hour light/12 hour darkness (weeks 0-3), then under conditions of constant dim light (weeks 4-7). Cages were equipped with running wheels connected to a continuous recorder, and daily tracings of running activity were recorded for 7 weeks. Computer analysis of wheel revolutions per hour with a chi 2 periodogram was used to calculate Qp, a measure of the amplitude of a circadian rhythm. The degree of PSS was measured by means of radioactive microspheres injected into the ileocolic vein and spleen. PVL rats were found to have PSS from the splenic and mesenteric territories of 88% and 27%, respectively; circadian periodicity was maintained in all PVL rats. PCA rats had complete shunting (greater than 99%) and showed a range of disrupted circadian rhythms from blunting of the amplitude to complete absence of the locomotor activity rhythm. This spectrum of disorganization occurred in spite of similar degrees of liver atrophy and weight gain. Whereas PCA in rats markedly disturbs the circadian rhythm of locomotor activity, animals with considerably less PSS from PVL exhibit normal behavior. The extent of PSS could be a variable affecting the expression of circadian rhythms in liver disease.

Liver DNA adducts in methyl-deficient rats administered a single dose of aflatoxin B1

Using an 8 week Solt-Farber protocol with selection pressure (2-acetylaminofluorene/partial hepatectomy) applied during weeks 6 and 7, we have observed that a single oral administration of aflatoxin B1 (AFB1) to Fischer 344 rats on day 1 of the study, followed by a 3 week feeding regimen of either a methyl-deficient (CMD) or a basal (CMS) diet, results in a relative increase in hepatic preneoplastic lesions in CMD diet fed rats. It has previously been shown that a multiple dosing regimen with AFB1, started after 3 weeks of CMD diet, enhances tumor incidence. In the present study, the role of metabolic activation in the induction of preneoplastic lesions, and liver DNA adduct levels after the first dose of AFB1 in the tumorigenesis model have been investigated. AFB1-DNA adducts were determined at 2-168 h following a single non-necrogenic (100 micrograms/kg body wt) or necrogenic (600 micrograms/kg body wt) dose of AFB1 on day 1 or day 21 of a 3 week treatment with a complete basal or CMD diet. In all rats irrespective of dose, dietary treatment or time of AFB1 dosing, the patterns of adduct formation and repair did not change. In rats receiving AFB1 on day 1, total DNA adduct levels between the diet or dose groups were not significantly different, and quantitatively did not correlate with the observed increase in preneoplastic lesions, suggesting a contribution by additional factors in the initiation of these lesions. Administration of AFB1 on day 21, however, resulted in significantly reduced levels of total adducts at both dose levels in CMD diet fed rats compared to controls. Serum biochemistry data suggest that a prolonged exposure to CMD diet may cause pathological and/or biochemical alterations in hepatocytes with a resultant decrease in metabolic activation of AFB1, thus making it difficult to evaluate whether DNA damage is directly related to tumorigenesis.

Level of DNA double-strand break rejoining in Chinese hamster xrs-5 cells is dose-dependent: implications for the mechanism of radiosensitivity

Rejoining of DNA double-strand breaks (dsb) was measured in a dsb repair-deficient mutant of CHO cells, xrs-5, after exposure to various doses of X-rays in the range between 15 and 50 Gy. For the experiments plateau-phase cultures were employed and dsb assayed by a pulsed field gel electrophoresis assay, the asymmetric field inversion gel electrophoresis (AFIGE). The half-times of dsb rejoining were larger in xrs-5 than in parental CHO cells and increased in both cell lines with increasing dose of radiation. The fraction of dsb remaining unrejoined after 240 min incubation at 37 degrees C was also higher in xrs-5 than in CHO cells, but decreased with decreasing dose of radiation. Although a decrease in the fraction of unrepaired dsb with decreasing dose has also been reported for repair-proficient cell lines, the extent of the phenomenon and its dependence on dose are entirely different in xrs-5 cells. We propose that this decrease in the fraction of unrejoined dsb with decreasing dose of radiation derives from the genetic alterations underlying the increased sensitivity to radiation of xrs-5 cells, and should be considered whenever results at the DNA level are correlated to results at the cell level. It is likely that similar responses will also be observed in other radiation-sensitive mutant cell lines deficient in dsb repair. There was no difference in the induction of dsb per Gy and dalton, as measured with AFIGE, between CHO and xrs-5 cells tested either in the exponential or in the plateau phase of growth.

Localization and detection of ovarian follicular fluid protein in follicles of human ovaries

Human ovarian follicular fluid protein has been partially purified and the active fraction designated as hGF2. Using specific polyclonal antiserum to hGF2, it was observed to be localized immunohistochemically in the granulosa cells of medium but not large follicles of human ovary. The hGF2 levels were estimated by ELISA in serum and follicular fluid of 10 gonadotropin-stimulated women recruited for IVF-ET programme. The results revealed a 3-fold increase in the concentration of hGF2 in follicular fluid compared to that in serum of these patients. These data indicate that the protein is secreted by granulosa cells and plays an important role in the regulation of follicular maturation and ovulation.

Comparison of four different ovarian stimulation protocols in an in vitro fertilisation & embryo transfer programme

Four different ovarian stimulation protocols were evaluated in an in vitro fertilisation and embryo transfer programme in 208 women (228 treatment cycles). In the rigid protocol (RP), 100 mg of clomiphene citrate (CC) was given from day 3 to day 7 of the menstrual cycle and 300 IU of human menopausal gonadotropin (hMG) was given from day 5 of the menstrual cycle. In the individualised protocol (IP) the same drugs and doses were used as in RP, but the day of initiation of CC depended on the length of the individual's menstrual cycle and hMG was administered from the last day of CC. In the programmed protocol (PP), ovarian function was suppressed with oral contraceptive pills (ethinyl estradiol 30 micrograms and norethisterone 1 mg) started on day 5 of the menstrual cycle for 45 to 70 days. Considering the last day of pill intake as day 0, CC was given for 5 days from day 5 and hMG (300 IU) from day 7. In the alternate day protocol (ADP), 100 mg of CC was administered from day 2 to day 6 and hMG (300 IU) was given on alternate days from day 2 to day 8 or day 10 of the cycle. In all the women, hCG (5000 IU) was administered when the diameter of at least 2 follicles was greater than or equal to 16 mm and estradiol levels were 300 pg/ml/dominant follicle. Patients not showing such a response were not treated further. The cardinal events of IVF-ET such as number of good responders, incidence of oocytes harvested, fertilised and embryos transferred per cycle were compared and it was concluded that the pregnancy rates were highest in women treated by the PP.

Haemagglutinin production by enterotoxigenic strains of Clostridium perfringens type A

Thirty-nine enterotoxigenic cultures of Clostridium perfringens type A were studied for enterotoxin and haemagglutinin production. Enterotoxin was quantitated by sandwich ELISA and DOT-ELISA techniques and haemagglutinin titres were determined using sheep and human erythrocytes. Haemagglutinins from only six cultures reacted against both sheep and human erythrocytes; a further 13 reacted only against human erythrocytes, and another five only against sheep cells.

Antifungal activity of HWA-138 and amphotericin B in experimental systemic candidiasis

HWA-138, a pentoxifylline analog, has been shown to increase yeast urinary clearance and to reduce yeast counts in the kidneys of rats infected with Candida albicans. Furthermore, HWA-138 has also been shown to prevent amphotericin B-induced acute renal failure in rats. We report here on the effects of HWA-138 alone and in combination with amphotericin B in the treatment of systemic candidiasis in mice. When single doses of HWA-138 were administered intravenously (10, 25, or 50 mg/kg of body weight) into infected mice, no significant improvement in survival was observed. In infected mice treated intravenously with multiple doses of HWA-138 (10, 25, or 50 mg/kg once daily for 5 consecutive days), a significant increase in survival time was seen only in animals also receiving 25 mg of HWA-138 per kg (14 +/- 3 days test versus 9 +/- 1 days control; P less than 0.05). The coadministration of subtherapeutic doses of amphotericin B and HWA-138 resulted in increased survival time. Combination therapy with amphotericin B (0.1-mg/kg single dose) and HWA-138 (10-, 25-, or 50-mg/kg multiple doses) resulted in a significant increase in survival time over controls (19 +/- 4, 19 +/- 5, and 21 +/- 9 days, respectively, versus 9 +/- 3 days; P less than 0.05). Combination therapy with amphotericin B (0.2-mg/kg single dose) and HWA-138 (10-, 25-, or 50-mg/kg multiple doses) also resulted in a significant increase in survival time over controls (24 +/- 6, 24 +/- 6, and 24 +/- 6, respectively, versus 9 +/- 3 days; P less than 0.05). Combination therapy with amphotericin B (0.2-mg/kg single dose) and HWA-138 (10-, 25-, or 50-mg/kg multiple doses) also resulted in a significant increase in survival time over controls (24 +/- 6, 24 +/- 6, and 24 +/- 6, respectively, versus 9 +/- 3 days; P < 0.05). Variance analysis of these findings indicate synergistic activity between amphotericin B and HWA-138 in the treatment of experimental candidiasis in mice.

Portacaval anastomosis disrupts circadian locomotor activity and pineal melatonin rhythms in rats

To determine whether hepatic encephalopathy may be associated with a disruption of circadian function, the circadian rhythms of locomotor activity and pineal melatonin content were examined in an animal model of complete portal-systemic shunting, rats with a portacaval anastomosis (PCA). The locomotor activity rhythm of all sham-operated animals entrained normally to a light/dark cycle and exhibited a normal free-running period during exposure to constant light. In contrast, PCA led to a dampening of the locomotor activity rhythm in all animals and the abolishment of a circadian periodicity in the activity rhythm of approximately 50% of rats during exposure to either a light/dark cycle or constant light. While normal diurnal variations of pineal melatonin content were seen in sham-operated rats, the amplitude of this variation appeared to be decreased in PCA animals. The similar effects of PCA on both a behavioral and an endocrine circadian rhythm, known to be regulated by a common neural pacemaker, coupled with studies indicating that a variety of other circadian rhythms may be disrupted in both animals and humans with hepatic dysfunction, suggests that this circadian disturbance originates within the pacemaker or on one of its afferent/efferent pathways.

Amsacrine is safe and effective therapy for patients with myocardial dysfunction and acute leukemia

The role of amsacrine in inducing remission in patients with cardiac disease and acute leukemia was evaluated. There were 17 patients with acute myelogenous leukemia (AML), six with acute lymphocytic leukemia (ALL), and one with biphenotypic leukemia. In this series of 24 patients whose disease had relapsed and who had reduced left ventricular ejection fraction, nine had a complete remission, seven with AML and two with ALL. In addition, four of six with newly diagnosed acute leukemia and reduced left ventricular ejection fraction also responded. Among nine patients who underwent endomyocardial biopsy, none had morphologic changes of sufficient degree to account for drug-induced heart failure. Patients with preexisting arrhythmias received amsacrine without incident if their serum potassium level was higher than 4.0 mEq/l at the time of drug administration. Amsacrine is safe and effective therapy for patients with acute leukemia and cardiac disease.

Vitamin K therapy in severe liver disease

A middle-aged man with parenchymatous liver disease and a decrease in vitamin K-dependent factors was given large doses of intravenous phylloquinone (10 mg/d for 20 days) without improvement in the synthesis of vitamin K-dependent factors. During subsequent liver transplantation, he exsanguinated. Although the exact role of over treatment with phylloquinone in this case is unclear, plasma levels of phylloquinone 300 times normal were attained after 5 days of treatment without effect on factors II, VII, IX, and X. Further therapy with vitamin K was unnecessary.

Age-related effects of chronic ethanol intake on vitamin A status in Fisher 344 rats

The present study was designed to investigate the interaction of age and ethanol on vitamin A status in rats. Rats aged 2 and 19 mo were fed a liquid diet containing 36% of total energy as ethanol or pair-fed a diet containing isoenergetic carbohydrate in place of ethanol. After 3 wk older rats had lower serum retinol (P = 0.04) and higher vitamin A concentrations in liver (P = 0.0001), esophagus (P = 0.0001) and the proximal (P = 0.03) and distal (P = 0.0001) colon than younger animals. Hepatic microsomal cytochrome P-450, retinyl ester hydrolase (REH) and cellular retinol-binding protein (cRBP) were significantly reduced; acyl coenzyme A: retinol acyltransferase (ARAT) was increased; and alcohol (retinol) dehydrogenase (ADH) activity was unchanged with age. Ethanol ingestion increased serum retinol as well as esophageal and colonic vitamin A levels in both age groups. Hepatic cRBP decreased further in the older rats with ethanol feeding, but no change was noted in the percentage of hepatic vitamin A as retinol or retinyl esters. Ethanol ingestion decreased REH (P = 0.0001) and ARAT activities (P = 0.02) and increased cytochrome P-450 (P = 0.04) but had no effect on the activity of ADH in either age group. These data indicate that, regardless of age, chronic ethanol ingestion significantly alters the tissue distribution of vitamin A; however, ethanol reduced cRBP levels only in older rats.

Sucking on the 'emptied' breast: non-nutritive sucking with a difference

A simple method to promote the use of human milk and subsequent breast feeding in low birthweight infants was evaluated in 32 babies. In the 'intervention' group (n = 16; mean (SD) weight 1559 (228) g and length of gestation 33.2 (1.8) weeks), infants were allowed to suckle at the breast when their general condition permitted after as much milk as possible had been expressed, and were then given the full required feeds by tube. Full breast feeding was started as soon as the infant could suck adequately. Sixteen control infants (mean (SD) weight 1605 (198) g and length of gestation 34.1 (2.4) weeks), were breast fed in the conventional manner only after it had been established that they could suck well; until then they received all their feeds by tube. After discharge the mean (SD) periods of exclusive and total breast feeding were longer in the group that had received the intervention (3.7 (1.3) and 5.1 (2.2) months, respectively) than among the controls (1.9 (0.6) and 3.3 (1.9) months, respectively). This 'intervention' method helps to promote milk formation, provides sucking experience for low birthweight infants without interfering with their nutritional intake and consequent weight gain, and encourages subsequent breast feeding with its well recognised advantages.

Endotoxin and the hyperdynamic circulation of portal vein-ligated rats

Humoral factors may be responsible for the hyperdynamic circulation seen in portal hypertension. Endotoxin, a peripheral arteriolar vasodilator, has been proposed to mediate this hemodynamic picture. We examined the pathogenic role of endotoxin in portal vein-ligated rats, a prehepatic portal hypertensive model with a well-developed hyperdynamic circulation. To this end, we (a) administered oral neomycin, a poorly absorbable antibiotic, at doses of 50 and 100 mg/day for 7 days and found no evident splanchnic hemodynamic effects of a 2-log-fold reduction of cecal aerobic bacterial flora as assessed by the radioactive microsphere technique in portal vein-ligated rats studied in the postanesthesia awake state; (b) assayed endotoxin in arterial samples using a quantitative limulus assay and found no evidence of endotoxinemia in PVL rats; (c) induced a state of endotoxin tolerance by repeated daily intraperitoneal injections of low-dose endotoxin and found no amelioration of the hyperdynamic state in portal vein-ligated rats. Our results do not support the hypothesis that endotoxin plays a major pathogenic role in the hyperdynamic circulation of this experimental model.

Nutritional support after liver transplantation: a randomized prospective study

Nutritional support in patients with advanced cirrhosis is difficult due to protein, fluid and salt restrictions. Successful liver transplantation should improve nutrient tolerance. We randomly assigned 28 hypoalbuminemic cirrhotic patients to receive, immediately after liver transplantation, one of three regimens: group 1, no nutritional support (n = 10); group 2, total parenteral nutrition (TPN) (35 kcal/kg/day) with standard amino acids (1.5 g/kg/day) (n = 8); or group 3, isocaloric isonitrogenous TPN with added branched-chain amino acids (n = 10). Therapy was continued for 7 days posttransplant. Jaundice resolution was unaffected by nutritional support. Nitrogen balance favored both TPN groups. Branched-chain amino acid (BCAA) aromatic amino acid ratios were highest in group 3. Coma scores and serum ammonia levels were similar in all groups. Both TPN groups achieved respirator independence earlier; this difference was not statistically significant. Group 1 patients stayed longest in ICU; the difference was statistically significant. TPN with either standard or BCAA- enriched amino acids is tolerated well immediately after successful liver transplant. Positive nitrogen balance is achieved; large protein loads do not worsen encephalopathy. Nutritional support may improve respiratory muscle function, allowing earlier weaning from ventilatory support. A shortened length of ICU stay justifies the expense of TPN.

Manganese levels in a jaundiced long-term total parenteral nutrition patient: potentiation of haloperidol toxicity? Case report and literature review

Manganese is vital in human nutrition. When oral intake is precluded, the recommended parenteral supplementation is 0.15 to 0.8 mg/day. Manganese is excreted primarily in the bile; during cholestasis, serum manganese levels may rise, and manganese toxicity ensue. Neuropsychiatric symptoms are prominent. Phenothiazine-derivative drugs may potentiate manganese toxicity. Serum or whole blood manganese levels should guide manganese therapy in jaundiced patients.

Screening tests for intrauterine growth retardation: a comparison of umbilical artery Doppler to real-time ultrasound

In a study designed to compare Doppler umbilical artery velocimetry to ultrasound morphometric measurements in the prediction of intrauterine growth retardation, 636 paired ultrasound and Doppler umbilical artery examinations were performed between 24 and 40 weeks gestational age. Intrauterine growth retardation was defined as birth weight less than the tenth percentile per gestational age and 25 (9.2%) of the infants born in our study met this criteria. In general, when the gestational age was limited to less than 30 weeks, none of the tests were highly predictive of intrauterine growth retardation. Doppler umbilical artery systolic-to-diastolic ratios of greater than 3 had the highest sensitivity. However, due to inclusion of a large number of false-positives, it was considered a poor test. After 30 weeks, fetal abdominal circumference less than the tenth percentile had a greater sensitivity (45%) and positive predictive value (28%) than Doppler systolic-to-diastolic ratios greater than 3 (36% and 18%, respectively). Doppler ultrasound umbilical artery systolic-to-diastolic ratios are not more predictive of intrauterine growth retardation than ultrasound morphometric measurements.

A simple method of evaluation of jaundice in the newborn

This paper evaluates a simple tool, the icterometer, in assessing jaundice in the newborn. The instrument consists of a perspex scale with yellow stripes of increasing intensity, numbered 1-5, alternating with transparent areas through which the infant's blanched skin colour can be seen and compared with the coloured stripes. The scale was found to be useful for more objective screening of neonatal jaundice, particularly in decreasing the number of blood samples to be taken for serum bilirubin. The present study suggests that serum bilirubin estimation can be avoided when the icterometer readings on the face are 3 or less, unless there is a rapid rise in jaundice within 24-36 h. However, a reading on the sole of even 1 is significant and requires assessment by trained staff for blood sampling and/or phototherapy. The instrument may also be useful to peripheral staff in developing countries when deciding on referral to specialist centres and to staff in specialist centres for screening cases of neonatal jaundice and decreasing the number of blood samples.

Inhibition of heterochromatin condensation of human Y chromosome by distamycin-A

Distamycin-A, an oligopeptide antibiotic with a N-methylpyrrole ring system and propionamide side chain, preferentially forms stable bonds with AT rich double stranded DNA. When introduced to cell cultures, it inhibits condensation of the heterochromatic region of the Y chromosome. The frequency of metaphases showing inhibition of heterochromatin condensation of the Y chromosome was found to be dependent on the treatment time and concentration of distamycin-A in the culture medium. When distamycin-A was added to a concentration of 100 micrograms/ml at the start of the culture (72 hours), the frequency of Y heterochromatin decondensation was found to be 48%, 30% and 6% in amniotic fluid, lymphocyte and fibroblast cultures respectively. The highest frequency of metaphases with decondensed Y heterochromatin were observed when distamycin-A treatment was carried out for the last 24 hours prior to harvest, the frequencies being 94%, 72% and 59% in amniotic fluid, lymphocyte and fibroblast cultures respectively. Increase in the concentration of distamycin-A from 25 micrograms/ml to 50 micrograms/ml during the last 24 hours of culture increased the incidence of metaphases with Y heterochromatin decondensation from 51% to 69% in amniotic fluid, 40 to 49% in lymphocyte and 29% to 31% in fibroblast cultures. Highest frequency of metaphases with Y heterochromatin decondensation were observed when the cultures were exposed to distamycin-A at a concentration of 100 micrograms/ml for the last 24 hours of culture.

Bone marrow transplantation for familial hemophagocytic lymphohistiocytosis

A one year old child diagnosed at two months as having familial hemophagocytic lymphohistiocytosis had a partial response to etoposide. He relapsed and underwent a bone marrow transplant after conditioning with etoposide 65 mg/kg, total body irradiation and cyclophosphamide 60 mg/kg X 2 doses. Post transplant sepsis ensued and the patient expired. At autopsy residual disease was noted. Familial hemophagocytic lymphohistiocytosis continues to be a fatal disorder and etoposide is the only agent known so far with any efficacy. Bone marrow transplantation probably should be attempted early in its course and may have a role in the treatment of this disease.

DOT-enzyme linked immunosorbent assay for detection of Clostridium perfringens type A enterotoxin

A procedure, which we have termed DOT-ELISA, to detect Clostridium perfringens type A enterotoxin on nitrocellulose paper is described. Seventy eight preparations from 39 cultures of C. perfringens type A were tested simultaneously by this and by Plate-ELISA methods. The results were comparable. DOT-ELISA detected as little as 0.02 micrograms of purified enterotoxin and 0.13 micrograms of enterotoxin in cell-free culture supernatant. As little as 0.02 micrograms purified enterotoxin mixed with human faeces could be detected specifically. The method is simple and does not require an ELISA reader.

Effect of Mycobacterium leprae-infected Schwann cells and their supernatant on lymphocyte neuroglia interaction

Since the resolution of neural lesions and subsequent nerve damage in leprosy must inevitably involve the participation of immune cells sensitized to Mycobacteria, we have used the dissociated Schwann cell culture model to study the relationship between M. leprae-infected Schwann cells and sensitized immune cells. Our earlier study on light and ultrastructural observations showed that on infection with M. leprae, the cytomorphology of Schwann cells remains unaffected, while degenerative changes suggestive of apoptosis are seen in extraneous lymphocytes which are subsequently phagocytosed by the Schwann cells. We now present additional evidence confirming that the phagocytosis of splenic cells by Schwann cells is indeed a two-step process. The first involves M. leprae-dependent cytotoxicity to splenic cells. This is followed by phagocytosis of these cells, which is a secondary and M. leprae-independent phenomenon. This finding has implications particularly on the weak inflammatory response observed in nerve lesions of a majority of lepromatous patients.

Cytotoxicity of N6-cycloalkylated adenine and adenosine analogs to mouse hepatoma cells

Cytotoxic effect(s) of N6-cycloalkylated adenine and adenosine derivatives, upon the viability of mouse hepatoma cells, were studied in vitro. N6-Cyclopropyl- and N6-cyclobutyladenine and adenosine derivatives (33 micrograms/ml; 24-48 h) exerted significant cytotoxic effects upon the cells. N6-Cyclopentyl- and N6-cyclohexyladenines exerted similar effects under different experimental conditions (133-166 micrograms/ml; 48-72 h), while no significant cytotoxic effect(s) were observed with the corresponding adenosine derivatives under these conditions. Observed physical changes in the treated cells included cell elongation, short stubby filaments, wide intracellular spaces and ruptured cell membranes. N6-Cycloalkylated nucleosides were usually more cytotoxic than the cycloalkylated bases.

The L protein of vesicular stomatitis virus modulates the response of the polyadenylic acid polymerase to S-adenosylhomocysteine

TsG16(I) is a temperature-sensitive (ts) mutant of vesicular stomatitis virus, Indiana serotype, which overproduces polyadenylic acid [poly(A)] in an in vitro transcription system due to a mutation in the L protein. Others have reported that L-S-adenosylhomocysteine (S-Ado-Hcy) causes wild-type (wt) virus to overproduce poly(A) in vitro. The possibility that tsG16(I) constitutively expresses a property induced by S-Ado-Hcy in the case of wt virus was found not to be so since polyadenylation by the mutant was still sensitive to S-Ado-Hcy. Indeed, S-Ado-Hcy caused tsG16(I) to overproduce poly(A) in vitro to a greater extent than its parental wt virus. The increase in polyadenylation observed in response to saturating levels of S-Ado-Hcy differed for tsG16(I), for its parental wt virus and for another wt strain. To characterize which viral protein modulated the polyadenylation response to S-Ado-Hcy, purified virions were fractionated and their phenotypes in homologous and heterologous reconstitution assays were examined. The results indicated that the viral L protein modulated the response in all three stocks of virus. These data provide further evidence to suggest that the L protein of vesicular stomatitis virus plays a role in polyadenylation of the viral mRNA.

Isolation and structure determination of Pachybasium cerebrosides which potentiate the antifungal activity of aculeacin

A set of four cerebrosides was isolated from a Pachybasium species and purified by preparative reversed-phase HPLC. All four products displayed activity in a natural product screen aimed at detecting novel cell wall-active antifungal agents based on synergy with the known glucan synthetase inhibitor, aculeacin. Based on degradation studies, fast atom bombardment mass spectrometry and 13C and high field 1H NMR techniques, the structure of the major cerebroside was determined to be (4E,8E)-N-D-2'-hydroxy-(E)-3'- hexadecenoyl-1-O-beta-D-glucopyranosyl-9-methyl-4,8-sphingadiene. The other components were found to be the corresponding 2'-hydroxypalmitic acid analog with one less double bond and an analogous pair containing 2'-hydroxystearic acid with and without the 3' double bond.

In vitro interaction of M. leprae-infected Schwann cells and splenic cells

The interaction between M. leprae-infected cultured Schwann cells and sensitized splenic cells was noted both under light and electron microscopy. No evidence of cytomorphological changes in infected Schwann cells was obtained. However, sensitized splenic cells were noted to undergo degenerative changes suggestive of the phenomenon of apoptosis. Subsequently a large number of these degenerated cells were observed within the Schwann cell. Such a process has not been hitherto reported in the histopathology of leprous nerves. Nevertheless, these findings indicate an aberrant metabolic function in M. leprae-infected Schwann cells.

Synergistic antifungal activity and reduced toxicity of liposomal amphotericin B combined with gramicidin S or NF

Amphotericin B (AmpB) disrupts membrane integrity by binding to sterols in fungal and mammalian cell membranes. The gramicidins, which form pores in all membranes but exhibit poor antifungal activity, are too toxic to mammalian cells to be used systemically. This study demonstrated synergistic antifungal activity of free and liposomal forms of AmpB when combined with the free and liposomal forms of gramicidin S and gramicidin NF against five Candida strains. In vitro erythrocyte lysis was prevented by using the liposomal forms of all drugs tested alone or in combination. Presumably, AmpB increases accessibility of the fungal cell membrane to the gramicidins, while liposome encapsulation decreases the rate of transfer of the drugs to the mammalian cell membrane. Liposome encapsulation of inactive or toxic drugs, used in combination with liposomal AmpB, may give new life to drugs previously believed to be inactive or too toxic for therapeutic consideration.

Micronucleus formation induced in rat liver and esophagus by nitrosamines

The rat hepatocarcinogen nitrosodimethylamine and the esophageal carcinogens nitrosomethylbenzylamine and nitrosomethylamylamine were shown to produce chromosomal damage, as manifested by micronucleus formation, in their target tissues. There was cross-reactivity in the two tissues, however, at high dose levels. Nitrosodiethylamine, which produces tumors in both the liver and esophagus in the rat, also produced micronuclei in both tissues.

Amsacrine treatment of patients with supraventricular arrhythmias and acute leukemia

Three patients with a history of supraventricular arrhythmia presented with relapse of acute leukemia. Two of the three patients were in sinus rhythm, receiving digoxin and/or verapamil daily. The third patient was in atrial fibrillation, but her heart rate was controlled with daily digoxin. All three patients received amsacrine without the occurrence of cardiac events. Although amsacrine may cause ventricular arrhythmias in the setting of hypokalemia, correction of the electrolyte abnormality permits its use in patients with a history of supraventricular arrhythmias.

A new regimen of amsacrine with high-dose cytarabine is safe and effective therapy for acute leukemia

Amsacrine and high-dose cytarabine (HiDAc), when administered as single agents, are effective treatment of acute leukemia. When used in combination, a high remission rate is also possible. We treated 47 patients with acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL), and blastic phase of chronic myelogenous leukemia (CML) with a combination of amsacrine and HiDAc. The patients received amsacrine 200 mg/m2 daily for three days and, concurrently, HiDAc 3 g/m2 over three hours once daily for five days. Of 20 evaluable patients with AML in relapse, there were 12 remissions; of seven additional patients with primary refractory AML, there were two remissions, and of 12 patients with ALL in relapse, there were eight remissions. The three patients with blastic phase CML and the three patients with biphenotypic leukemia did not respond. Nausea, vomiting, stomatitis, hepatic dysfunction, and diarrhea were common, but cutaneous, conjunctival, and significant cerebellar and cerebral side effects were absent. We conclude that this regimen is highly effective therapy for AML and ALL and is also safe, eliminating the major toxicities encountered with HiDAc.

Polymerized phospholipid vesicles containing amphotericin B: evaluation of toxic and antifungal activities in vitro

We have prepared lipid vesicles (liposomes) composed of polymerized bis[12-(methacryloyloxy)dodecanoyl]-L-alpha-phosphatidylcholine (DPL) which contain the antifungal polyene antibiotic amphotericin B (AMB). It was necessary to devise a novel method for incorporating AMB into the liposomes subsequent to polymerization. The polymer liposome AMB was as effective as AMB in "conventional" liposomes in terms of inhibiting fungal growth in vitro. However, in contrast to "conventional" liposomes, the polymerized DPL vesicles did not protect mammalian cells against AMB induced toxicity.

Effects of sterols on the therapeutic efficacy of liposomal amphotericin B in murine candidiasis

Incorporation of amphotericin B (AMP-B) into phospholipid vesicles (liposomes) has been shown previously to decrease AMP-B toxicity while retaining the antifungal efficacy of the drug. In this report, the role of sterols in the formulation of liposomes as well as in their effectiveness in the treatment of murine candidiasis have been investigated. The presence of ergosterol or cholesterol at different lipid ratios did not augment the encapsulation efficiency of AMP-B as compared with vesicles containing phospholipids alone. There was no significant difference in the survival time of mice infected with Candida albicans treated with sterol-containing vesicles compared with those treated with sterol-free vesicles. These findings suggest that the sterol-free liposomes might be of advantage for delivering AMP-B because of its simple formulation, lack of toxicity, and ease of preparation.

Selective toxicity and enhanced therapeutic index of liposomal polyene antibiotics in systemic fungal infections

Incorporation of the polyene antibiotic amphotericin B (AMB) in liposomes results in a marked reduction in drug toxicity with no loss of antifungal potency. Nephrotoxicity, the dose-limiting side effect of AMB, is almost abolished when the drug is utilized in a liposomal carrier. Because of reduced toxicity, high doses of liposomal AMB can be used, resulting in superior therapy of systemic fungal infections in mice. The improved therapeutic index of liposomal AMB versus free AMB is also manifest in infected neutropenic animals. The reduced toxicity of liposomal AMB is due to a fundamental alteration in the interaction of the drug with mammalian cell membranes. AMB transfers effectively from donor liposomes to fungal cell walls and membranes and is thus toxic to fungi. By contrast, AMB does not transfer from liposomes to mammalian cells and thus is not toxic to these cells. Thus, the use of liposomal AMB may offer a marked improvement in the therapy of systemic fungal infection in cancer patients and other immunodebilitated individuals.

Liposomal amphotericin B for the treatment of systemic fungal infections in patients with cancer: a preliminary study

Twelve patients with hematologic malignancies complicated by fungal infections were treated with liposomal amphotericin B (L-AmpB). Nine patients were granulocytopenic; the three additional patients with normal granulocyte counts were immunosuppressed. All patients had biopsy findings or cultural evidence of the progression of their fungal infection while being treated with conventional amphotericin B. Doses of 0.8-1.0 mg/kg of L-AmpB were administered intravenously every 24-72 hr. Three patients had a complete remission, five had a partial remission, and four showed no improvements. A total of 161 doses of L-AmpB were administered. Fever and chills occurred on seven occasions. No hematologic or blood chemistry abnormalities related to L-AmpB treatment were observed.

Cortically evoked motor action potential in spinal cord injury research

Somatosensory evoked potentials (SEPs) have been used extensively in the neurophysiological assessment of spinal cord integrity. However, SEPs mainly reflect the function of the dorsal column. In an effort to find a reliable method of assessing the integrity of the motor tracts for experimental purposes, we studied cortically evoked motor action potentials (CEMAPs). Twenty white rats used were anesthetized with ketamine, and extradural cortical stimulation was carried out through a parasagittal craniectomy posterior to the coronal suture. A single stimulus of 325 mV for a duration of 0.1 to 0.5 ms was used to obtain a motor action potential from the contralateral lower extremity. Complete transsection of the spinal cord abolished the CEMAP. A progressive increase in pressure applied to the spinal cord with a progressive increase in duration produced loss of the CEMAP. The selective motor tract study made possible by cortical stimulation makes this a good technique for studying the motor tracts in experimental work.