Impaired clearance of ceftizoxime and cefotaxime after orthotopic liver transplantation

The pharmacokinetics of ceftizoxime (CZX) and of cefotaxime (CTX) were studied in five children and five adults after orthotopic liver transplantation (OLT). Delayed clearance of CZX (clearance of 0.21 to 1.26 ml/min per kg [body weight]) and CTX (clearance of 0.40 to 1.49 ml/min per kg) occurred in 7 of the 10 OLT patients. We conclude that abnormal CZX and CTX clearance is common after OLT and may be associated with minimal change in serum creatinine.

Pulmonary complications following methotrexate therapy

Methotrexate is frequently used in the treatment of severe psoriasis, and its hepatotoxicity has long been recognized by dermatologists. Pulmonary complications resulting from use of the drug are uncommon but should be considered in any patient on methotrexate who develops pulmonary symptoms in the absence of infection. We describe two patients, one who developed an acute pneumonitis and one with progressive pulmonary fibrosis following long-term, low-dose methotrexate for psoriasis. Early recognition of these complications by lung function testing and withdrawal of the drug, when necessary, may arrest or reverse methotrexate-induced lung disease.

Diagnosis and therapy of neuroectodermally associated tumours using targeted radiation

Monoclonal antibodies have been proposed as targeting agents for cytotoxic compounds in vivo. We have undertaken a phase 1 study of 131I UJ13A in patients with neuroblastoma as well as a pilot study for the intrathecal use of radiolabelled conjugates for diffuse malignant meningitis. Access to solid tumour deposits appears to be a major problem in targeting sufficient isotope to elicit a therapeutic response. This, however, is overcome in the intrathecal use of antibodies for diffuse disease. Problems have also been identified in changes in the pharmacokinetics of antibody handling that occur on repeated administration of conjugate to patient. This is presumably due to the generation of an anti-mouse Ig response. These studies indicate some of the limitations in using murine antibodies as targeting agents and point to areas where their use may be of maximal effect.

Pulmonary function in patients on long-term, low-dose methotrexate

We have made a detailed study of pulmonary function in patients receiving long-term, low-dose methotrexate for psoriasis. We were unable to detect any changes indicative of early pulmonary damage.

Radioimmunolocalization of human brain tumours: biodistribution of radiolabelled monoclonal antibody UJ13A

Monoclonal antibody UJ13A, radiolabelled with 131I, was intravenously administered to patients with primary brain tumours. The antigen recognised by UJ13A is present on most neuroectodermally derived tissue. The ratio of uptake in tumour to normal brain, assessed by scintigraphy, improved with time. Maximal tumour uptake occurred between 4 and 48 h. Dynamic and static scintigrams indicated some early sequestration of radiolabelled antibody by the liver. Tumours were surgically resected in seven patients at various intervals after antibody administration showing tissue to blood ratios increasing with time in all parts of the lesion (viable and necrotic tumour, cyst fluid), and in normal brain. The highest tissue to blood ratio in viable tumour was 5.1 at 16 days after injection. In tissues resected 2-3 days after injection there was relatively greater uptake in the viable tumour compared to necrotic tumour and cyst fluid. In contrast, tissues resected later (6-16 days) showed greater uptake in ischaemic tissue than viable tumour, suggesting diffusion was an important factor influencing tumour uptake. The amount of radioactivity per gram of tumour tissue was less than 0.005% of the injected dose. Future studies are needed using different antibodies, antibody fragments and additional methods of optimising delivery.

Trochanteric fractures of the femur. A randomised prospective trial comparing the Jewett nail-plate with the dynamic hip screw

In a randomised prospective trial 98 elderly women with trochanteric fractures of the femur were treated with either a 135 degrees Jewett nail-plate or a 135 degrees Dynamic hip screw. The results at six weeks, three months and six months were statistically analysed. There were no significant differences in the two groups with regard to pain, length of hospital stay, morbidity or mortality. Although operative difficulties and open reduction were more common with the Dynamic hip screw, at the end of six months more patients in this group were mobile and there was significant radiological evidence of better compression without loss of fixation.

Protein engineering of homodimeric tyrosyl-tRNA synthetase to produce active heterodimers

Heterodimers of tyrosyl-tRNA synthetase from Bacillus stearothermophilus have been produced by mutagenesis at the subunit interface. Oppositely charged groups have been engineered into the subunits so that they can form a complementary pair. Wild-type tyrosyl-tRNA synthetase is a symmetrical dimer in which the side chains of the 2 Phe-164 residues interact at the subunit interface. Phe-164 was mutated to Asp in tyrosyl-tRNA synthetase and to Lys in a truncated enzyme (des-(321-419)tyrosyl-tRNA synthetase) which lacks the two tRNA-binding sites, but which can catalyze pyrophosphate exchange. The size difference allows subunit association to be studied by gel filtration chromatography. These changes induce reversible dissociation from active dimers into inactive monomers at pH values which favor ionization at position 164. A mixture of the two mutants near neutral pH is apparently fully active in pyrophosphate exchange and consists of a heterodimer of [Asp164]tyrosyl-tRNA synthetase and [Lys164]des-(321-419)tyrosyl-tRNA synthetase. Despite having only one binding site for tRNA, heterodimer has full aminoacylation activity at high concentrations of tyrosine. We have therefore produced a family of dimers that differ in stability near neutral pH. This novel approach using protein engineering allows specific dimerization of subunits of the same size that have different defined mutations, each subunit being tagged by the charge. Such hybrid proteins can be used to study subunit interaction.

Carotid endarterectomy in the octogenarian: is it appropriate?

To evaluate the role of carotid endarterectomy (CE) in patients 80 years and older an 8-year study of 172 nonrandomized cases of octogenarians with cerebrovascular disease was done. Ninety octogenarians underwent CE whereas 82 octogenarians, with arteriographically established carotid artery disease, were not operated on and served as a control series. The stroke rate after CE was 6%. In follow-up extending to 8 years the late stroke rate was only 2%, whereas the cumulative long-term stroke rate in the nonoperated group was 16%. These late strokes were appropriate to the side of the arteriographically demonstrated disease. In 1008 nonoctogenarians who underwent CE during this same time interval, the stroke rate after CE was 2% and the mortality rate was 0.6%. In the octogenarian population, however, the mortality rate after stroke was an alarming 40% in the operated group and 62% in the nonoperated control group. Arteriographic flow-limiting (greater than 75% stenosis) intracranial occlusive disease was identified in 53% of the octogenarians undergoing operation and in all patients who suffered a postoperative neurologic deficit. This incidence of severe intracranial disease was nearly five times that of the nonoctogenarian patients undergoing CE. Although the stroke rate after CE in the octogenarian patient was 6%, the late stroke rate was only 2% compared with the cumulative stroke rate of 16% in the nonoperated octogenarian patients. Severe intracranial occlusive disease and, therefore, flow deprivation may play a more significant role as a cause of postoperative deficits than in younger patients, but CE is appropriate for selected octogenarians on the basis of physiologic rather than chronologic age.

The bacterial mutagenicity of nitropolychlorinated dibenzo-p-dioxins

The bacterial mutagenicity of 2-nitrodibenzo-p-dioxin, a mixture of 2-nitro-7-chloro- and 2-nitro-8-chlorodibenzo-p-dioxin, 7-nitro-2,3-dichloro-, 8-nitro-2,3,7-trichloro-, 2-nitro-1,3,7,8-tetrachloro- and 3-nitro-1,2,4,7,8-pentachlorodibenzo-p-dioxin was determined using Salmonella typhimurium tester strains TA98 and TA100 with and without rat hepatic S9 for metabolic activation. All the nitro-PCDDs exhibited some direct-acting mutagenicity with both tester strains, however, the activity was significantly lowered in the presence of exogenous S9 and the compounds were more mutagenic to tester strain TA98. The mutagenicity of the nitro-PCDDs was also dependent on structure because there was a marked decrease in activity with increasing chlorine content. Because nitro-PCDDs have recently been identified as incomplete combustion products of municipal waste, this study confirms that this new class of compounds contains some bacterial mutagens.

131-I coupled to monoclonal antibodies as therapeutic agents for neuroectodermally derived tumors: fact or fiction?

It has been suggested that monoclonal antibodies may be useful in targeting cytotoxic compounds to tumor cells. We have explored their use in targeting 131-I to highly radiosensitive primitive neural tumors such as neuroblastoma and pineoblastomas. Two routes of administration have been employed, intravenous and intrathecal. Our current experience in using radiolabelled antibodies is described, indicating toxicities seen and any therapeutic benefit observed. The results of the study suggest that if targeted radiation has a role in the treatment of these malignancies, it will be restricted to the eradication of small tumor masses from the body.

Two distinct classes of IgG Fc receptors on a human monocyte line (U937) defined by differences in binding of murine IgG subclasses at low ionic strength

We have defined two distinct classes of IgG Fc receptors (FcR) on cells of a human monocytic line (U937) by analyzing the direct binding of murine IgG subclasses in medium of low ionic strength. Four lines of evidence support this contention. The binding of aggregated murine IgG2b (AggmIgG2b) to U937 and Daudi cells was enhanced at low ionic strength, whereas monomeric murine IgG2a (mIgG2a) did not bind to Daudi cells and its high affinity binding to U937 cells was unaffected by changes in ionic strength. Double reciprocal inhibition experiments with U937 cells indicated that the binding of both ligands was inhibited 30 to 135 times more efficiently by the homologous ligand than by the heterologous one. That is, the binding of 125I-AggmIgG2b was inhibited 50% by 3.5 micrograms/ml of AggmIgG2b and 100 micrograms/ml of mIgG2a. Similarly, the binding of 125I-mIgG2a was inhibited 50% by 2.5 micrograms/ml of mIgG2a and only 44% by 243 micrograms/ml of AggmIgG2b. A monoclonal antibody of the IgG2b subclass raised against an IgG FcR on K562 cells inhibited binding to U937 cells of AggmIgG2b but not of mIgG2a. Trypsinization of U937 cells abrogated by 32% the binding of mIgG2a but did not affect the binding of AggmIgG2b. Human IgG inhibited binding of both AggmIgG2b and mIgG2a to U937 cells. We propose that the newly recognized FcR that binds AggmIgG2b is the human homologue of the murine macrophage IgG2b/1 FcR (FcRII), and that the previously described 72,000 dalton high-affinity FcR on U937 cells that binds mIgG2a is the human equivalent of the murine macrophage IgG2a FcR (FcRI).

Two distinct classes of IgG Fc receptors on a human monocyte line (U937) defined by differences in binding of murine IgG subclasses at low ionic strength

We have defined two distinct classes of IgG Fc receptors (FcR) on cells of a human monocytic line (U937) by analyzing the direct binding of murine IgG subclasses in medium of low ionic strength. Four lines of evidence support this contention. The binding of aggregated murine IgG2b (AggmIgG2b) to U937 and Daudi cells was enhanced at low ionic strength, whereas monomeric murine IgG2a (mIgG2a) did not bind to Daudi cells and its high affinity binding to U937 cells was unaffected by changes in ionic strength. Double reciprocal inhibition experiments with U937 cells indicated that the binding of both ligands was inhibited 30 to 135 times more efficiently by the homologous ligand than by the heterologous one. That is, the binding of 125I-AggmIgG2b was inhibited 50% by 3.5 micrograms/ml of AggmIgG2b and 100 micrograms/ml of mIgG2a. Similarly, the binding of 125I-mIgG2a was inhibited 50% by 2.5 micrograms/ml of mIgG2a and only 44% by 243 micrograms/ml of AggmIgG2b. A monoclonal antibody of the IgG2b subclass raised against an IgG FcR on K562 cells inhibited binding to U937 cells of AggmIgG2b but not of mIgG2a. Trypsinization of U937 cells abrogated by 32% the binding of mIgG2a but did not affect the binding of AggmIgG2b. Human IgG inhibited binding of both AggmIgG2b and mIgG2a to U937 cells. We propose that the newly recognized FcR that binds AggmIgG2b is the human homologue of the murine macrophage IgG2b/1 FcR (FcRII), and that the previously described 72,000 dalton high-affinity FcR on U937 cells that binds mIgG2a is the human equivalent of the murine macrophage IgG2a FcR (FcRI).

Reversible dissociation of dimeric tyrosyl-tRNA synthetase by mutagenesis at the subunit interface

Dimeric tyrosyl-tRNA synthetase from Bacillus stearothermophilus exhibits half-of-the-sites reactivity and negative cooperativity in binding of tyrosine. Protein engineering has been applied to the enzyme to determine whether it can be reversibly dissociated into monomers and if the monomers are active. The target for mutation is the residue Phe-164. The side chain of Phe-164 in one subunit interacts with its symmetry-related partner in the other. Mutation of Phe-164----Asp-164 gives a mutant [TyrTS(Asp-164)] that undergoes dissociation at high pH when the aspartate residues are ionized. The monomer is inactive and does not bind tyrosine. Dissociation is enhanced at low concentrations of enzyme by a mass action effect. Kinetic and binding measurements on TyrTS(Asp-164) with tyrosine and tyrosyl adenylate show that the monomer has very weak affinity for these ligands. Accordingly, dimerization is favored by high concentrations of tyrosine and ATP since the dimeric form has a high affinity for the ligands. The presence of tRNA does not encourage dimer formation, and so it must bind to the monomer. TyrTS(Asp-164) is fully active at pH 6 where dimerization is favored but has low activity at pH 7.8 where dissociation is favored. It should now prove possible to engineer heterodimers that may be used to investigate the subunit interactions further.

The jugular vein as an interposition graft in the distal splenorenal shunt

The selective distal splenorenal shunt is the preferred portal decompression procedure for patients with refractory bleeding esophageal varices. An autogenous jugular vein interposition graft in the distal splenorenal position obviates the tedious struggle associated with mobilizing the splenic vein from the pancreatic substance, thereby lessening blood loss, avoiding postoperative pancreatitis and shortening operative time. An autogenous jugular vein interposition distal splenorenal shunt can, therefore, be performed with less morbidity while affording the same physiologic benefits as the standard distal splenorenal shunt.

Hexachlorophene as a topically applied chemical for prophylaxis against Schistosoma mansoni infections in mice

Treatment of mouse tail skins with hexachlorophene (1.25% w/v) in absolute methanol or 70% isopropanol suppressed Schistosoma mansoni infections by more than 95% even when the application was performed up to three days prior to exposure to cercarial suspensions by tail immersion. Treatment with concentrations of 0.313% or higher one day prior to exposure provided at least 98% protection when the treated surface was not subjected to water washes of greater duration than 1/2 hour. Tail immersion application of 1.25% hexachlorophene one day prior to exposure still provided 87-92% protection after 3 hours water wash. Wipe application of 1.25% hexachlorophene three days prior to exposure still provided 93% protection following 3 hours water wash. High cercarial recoveries from exposure tubes at the end of exposure periods indicated high antipenetrant activity for hexachlorophene. Sufficient hexachlorophene leached from treated tail skins into the surrounding water to affect subsequently added cercariae so that they were no longer infective to untreated mice.

Therapeutic application of a radiolabelled monoclonal antibody in nude mice xenografted with human neuroblastoma: tumoricidal effects and distribution studies

Monoclonal antibody UJ13A radiolabelled with isotopes of iodine has been shown to selectively localize to human neuroblastoma xenografts. When 131I-UJ13A conjugates were given to nude mice at high doses (100-150 microCi), tumours temporarily disappeared, only to regrow. No selection for neuroblastoma cells that were UJ13A - negative was observed. Distribution studies on mice receiving radiolabelled UJ13A demonstrated the antibody is rapidly lost from the blood of animals. This cannot be accounted for by selective uptake into xenografts or any other mouse organ examined. We concluded there is a rapid equilibration of isotope between intra- and extravascular spaces in the animal. The rapid, biphasic loss of UJ13A from the blood of mice may explain why so little injected antibody can target to the human tumour xenografts.

Conventional superficial X-ray versus Grenz ray therapy in the treatment of constitutional eczema of the hands

Twenty-five patients with symmetrical constitutional eczema of the hands, resistant to topical treatment, took part in a double-blind trial which showed that 300 rad (3 Gy) of conventional superficial X-ray therapy was superior to 900 rad (9 Gy) of Grenz ray therapy (both given in three divided doses at 21 day intervals).

Fc receptor-mediated binding and endocytosis by human mononuclear phagocytes: monomeric IgG is not endocytosed by U937 cells and monocytes

Fc receptor-mediated endocytosis of monomeric IgG1 by human mononuclear phagocytes was evaluated under conditions where aggregated IgG and insulin readily undergo receptor-mediated internalization. U937 cells or normal human peripheral blood monocytes were incubated at 37 degrees C in the absence of free radioligand after having first bound 125I-IgG1 at 0 degrees C. To determine the amount of cell-associated IgG1 internalized after varying periods of 37 degrees C incubation, surface-bound IgG1 was removed by sequential exposure of cells at 0 degrees C to a nonspecific proteinase for 1 h and to acetic acid at pH 3.2 for 3 min. The failure to develop a proteinase- and acid-resistant fraction, similar to that seen over time at 37 degrees C in parallel experiments with 125I-insulin and 125I-aggregated IgG, and the lack of degradation of the IgG1 released into the medium from the same cells over time show that these cells do not endocytose and degrade monomeric IgG by an Fc receptor-specific mechanism and suggest that constitutive recycling without degradation is unlikely to be occurring. These data fulfill one prediction of the hypothesis that receptor-receptor interaction triggers Fc receptor-mediated endocytosis.

Stability of the complex formed between French bean (Phaseolus vulgaris) phenylalanine ammonia-lyase and its transition-state analog

Phenylalanine ammonia-lyase forms trans-cinnamate from L-phenylalanine, and thus stands at a gateway to secondary metabolism in higher plants. L-alpha-Amino-oxy-beta-phenylpropanoic acid (L-AOPP), a very effective competitive inhibitor of this enzyme, is most probably a transition-state analog for the elimination reaction. A preparation of phenylalanine ammonia-lyase (PAL), obtained from diluted suspension cultures of French bean cells, was used to investigate the binding of this compound in vitro. After extensive dialysis, the inhibitor remained tightly bound to the enzyme unless both an increased temperature and L-phenylalanine were provided, when the spectrophotometer trace of enzyme activity gradually approached linearity. Under such optimal catalytic conditions (37 degrees C; 25 mM L-phenylalanine; pH 8.8), dissociation of the enzyme-ligand complex took place with a half-time of approx 10 min. (This is much longer than reported for the enzyme from maize.) The consequences of these findings are discussed for investigations where L-AOPP is applied in vivo. These experiments have shown that the irreversible binding of the transition-state analog under appropriate conditions (0-4 degrees C, no L-phenylalanine) gave continued protection against attack on the enzyme by an excess of borohydride. By titrating the enzyme with increasing concentrations of analog and measuring the degree of protection afforded, the active-site concentration has been estimated. The turnover number (kcat = 0.8 s-1) given by this novel approach is of the same order of magnitude as previously reported from extensive purification of enzyme from other species.

Resolution and identification of the "subunits" of cytochrome C oxidase from mouse liver

Mouse liver cytochrome c oxidase was purified to a specific heme a content of 9.3 nmol/mg protein and the constituent polypeptides separated on SDS-polyacrylamide gel electrophoresis. Using this system, the enzyme was resolved into 12 to 14 polypeptide bands.

Is there a role for radioimmunolocalization in diagnosis of intracranial malignancies?: discussion paper

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A comparison of avian and rodent S-9 liver homogenates in the Ames test

Avian S-9 liver homogenates were obtained from phenobarbital, 3-methylcholanthrene (3-MC), polychlorinated biphenyl (Aroclor 1254) induced and control chickens. These homogenates were tested for their capacity to metabolically activate benzo[a]pyrene (B[a]P) and cyclo-phosphamide in the Salmonella typhimurium assay. Liver homogenates from 3-MC, Aroclor 1254 and phenobarbital induced chickens were more active in converting B[a]P to its ultimate mutagenic form than was S-9 obtained from Aroclor 1254 induced rats. However, Aroclor 1254 induced rat S-9 was superior to Aroclor 1254 induced avian S-9 in metabolically activating cyclophosphamide.

HLA DR typing of aspirin sensitive asthmatics

Previous studies have suggested associations of HLA, A, B and C loci antigens with specific subgroups of asthma. We applied DR antigen typing to the aspirin sensitive subgroup to look for similar correlations. Our results show no statistically significant increase in any known DR antigen nor any correlation with A or B locus typing. We did find a non-statistically significant increase in the number of subjects with blank typing at the DR locus, (i.e., a presently unidentified antigen), raising the question of whether a correlation may exist with an as yet undefined antigen.

Acute exposure to hymenoxon: electron microscopic study of the mouse liver

Young, male mice (25 to 30 g) were given oral doses of hymenoxon, a sesquiterpene lactone, for 5, 10, or 20 days. Hymenoxon, isolated from Hymenoxys odorata DC, was dissolved in dimethyl sulfoxide (DMSO) and water (1:1, v/v) and was administered daily at a dosage level of 100 mg/kg of body weight for 5, 10, or 20 days. Two control groups were maintained; 1 group was given DMSO and water, and 1 group was given water only. Twenty-four hours after the last dosing, the mice were euthanatized and their livers were processed for transmission electron microscopy. Hepatocyte organelles of hymenoxon-treated mice appeared normal although the bile canaliculi contained a fine granular material and membranous structures, including myelin figures. The canaliculi of hymenoxon-treated mice were also markedly dilated, compared with bile canaliculi in the control groups. The mean area of bile canaliculi of the 5-, 10-, and 20-day mice was 14.08 microns2, 15.65 microns2, and 17.56 microns2, respectively, compared with 7.73 microns2 for the canaliculi of DMSO + water-treated mice. The P values were less than 0.001, 0.02, and 0.05 for the 5-, 10-, and 20-day hymenoxon-treated mice, respectively. Seemingly, the mouse was not a good model for studying hepatic ultrastructural changes produced by hymenoxon, using dosages less than or equal to 100 mg/kg/day for 20 days.

An ELISA to detect monoclonal antibodies specific for lipid determinants of Mycoplasma pneumoniae

An enzyme-linked immunosorbent assay (ELISA) was developed for analysis of monoclonal antibodies directed towards lipid determinants of Mycoplasma pneumoniae. Chloroform-methanol lipid extracts as well as chromatographed lipid fractions of M. pneumoniae were bound to polyvinylchloride microtiter wells. Of 293 clones positive to M. pneumoniae as detected by a whole cell ELISA, a total of 78 clones produced antibodies which selectively bound to lipid extracts of M. pneumoniae. The simplicity and reproducibility of the assay permit rapid screening for detection of antibodies directed against non-protein cellular antigens.

The penetration of misonidazole and desmethylmisonidazole into brain tumours and other central nervous system tissues in man

The concentration of drug after oral administration of 1 g misonidazole to patients undergoing neurosurgery has been studied in samples taken from intracerebral tumours, normal brain, cerebrospinal fluid and brain tumour cyst fluid. A total of 31 patients yielded samples at various times 2-8 h after drug administration. Results show a considerable range of tumour/plasma percentages but from about 2-5 h after drug administration this averaged between 65-80%. Normal brain and CSF showed similar good penetration but drug entry into cyst fluid was lower (30-50%). A further study with desmethylmisonidazole given to 11 additional patients showed a similar range of tumour penetration but lower concentrations in CSF and cyst fluid (10-20%). Low values were also seen in some but not all of the normal brain tissue samples. Necrotic tumour also had much lower concentrations than macroscopically viable tissue. These results are discussed in terms of their clinical relevance to sensitiser studies on patients with brain tumours with drugs of different lipophilicities.

The role of microsomal enzyme inducers in the reduction of misonidazole neurotoxicity

In a series of studies, we have shown that phenytoin, 300 mg daily for one week, produces consistent hepatic microsomal enzyme induction, resulting in a decrease of 25% in misonidazole half-life, without causing any toxicity per se. A longer period of administration gives only a slightly greater induction. Phenobarbitone in a daily dose of 90 mg causes a reduction of 18% and 23% in misonidazole half-life after 1 and 2 weeks' pre-treatment respectively, but is less suitable clinically because of its sedative effect. A further series of studies using phenytoin as the inducing agent has shown that, despite adequate enzyme induction and increased misonidazole metabolism, it is impossible to increase the total dose of misonidazole beyond the usually accepted value of 12 g/m2 because of unacceptable neuropathy (a rate of 50% at a dose of 14 g/m2 over three weeks). In single doses of above 3.0-4.0 g of misonidazole, severe nausea and vomiting are prominent, so that this side effect is a determining factor in the treatment fractionation. Audiometric studies show no correlation between the incidence of peripheral neuropathy and abnormal audiograms, and have no value in the early prediction of neurotoxicity. It seems that despite causing increased metabolism, enzyme induction does not protect against neurotoxicity and thus will not permit the use of higher doses of misonidazole for increased radiosensitisation.

Amoscanate as a topically applied chemical for prophylaxis against Schistosoma mansoni infections in mice

Amoscanate (0.1% w/v) in methanol solution applied to skin by tail immersion 1 day prior to cercarial exposure provided mice with better than 90% protection against mature Schistosoma mansoni infections. Cercariae penetrated and schistosomula migrated from treated skins as readily as in control skins. Lung incubation assays, however, indicated that day 7 lung worm burdens were only about half those of control values. By day 20, worm burdens were reduced further to approximately 15% of those for control mice. The delayed prophylactic activity was apparently not due to percutaneously absorbed compound. Wipe application of amoscanate to the skin was nearly as effective as immersion.

Binding and uptake of concanavalin A into rat brain synaptosomes: evidence for synaptic vesicle recycling

The specific binding of radioiodinated concanavalin A (125I-con A) to rat brain synaptosomes was shown to be saturable. In the presence of excess on A binding was rapid and was completed within 5 min (t1/2 was 25 s) at 37 degrees C, and at saturation the amount bound did not change over time. Under the electron microscope, concanavalin A-ferritin (con A-ft) bound to synaptosomes in two regions: in the extra-junctional plasma membrane and within the synaptic cleft of Gray type 1 and 2 synapses. Synaptosomes incubated with con A-ft at 37 degrees C internalized bound lectin by endocytosis through coated pits. Endocytosis took place in the extra-junctional membrane, because it can occur before con A-ft has penetrated into the synaptic cleft, and continued for a considerable time (more than 30 min) after saturation of the receptor(s). Synaptic vesicles, which have at least two con A receptors on the internal aspect of their membranes, and cisternae, become labelled. When exocytosis was induced in synaptosomes by K+ depolarizations, synaptic vesicle con A receptors became incorporated into the plasma membrane and were labelled with 125I-con A causing a 2.5-fold increase in con A binding that was Ca2+ dependent. These experiments thus provide evidence for the transient incorporation of synaptic vesicle membrane glycoproteins into the plasma membrane during transmitter release.

The role of dexamethasone in the modification of misonidazole pharmacokinetics

A review of misonidazole pharmacokinetics in 83 consecutive patients treated for tumours other than glioma has shown that among patients not receiving enzyme-inducing agents the plasma elimination half life is lower in patients taking steroids. Such a difference is not seen if patients already taking enzyme inducers are given steroids. Five further patients with carcinoma of the lung, treated with radiation over a period of 3 weeks, have been studied in greater detail. Misonidazole, in oral dose of 1 gm-2, was given in conjunction with the first and last radiotherapy fractions, and dexamethasone, in a divided daily dose of 8 mg, was given throughout the radiation treatment, commencing after the first treatment. Misonidazole pharmacokinetics were studied at each administration. Following the dexamethasone treatment period there was a 25% reduction in misonidazole plasma elimination half life, a 24% reduction in plasma AUC0-00, and a 38% increase in 24 h urinary excretion (all changes being statistically significant--P less than 0.005). No changes were observed in the plasma AUC0-24 and urinary excretion of the major metabolite desmethylmisonidazole. Glomerular filtration rates in one patient, before and after treatment with dexamethasone, remained unchanged. These results suggest that the effect of dexamethasone on misonidazole kinetics is not related to an enhancement of demethylation.

Increased expression of human monocyte HLA-DR antigens and Fc gamma receptors in response to human interferon in vivo

The expression of class II MHC encoded antigens (HLA-DR) and Fc gamma receptors by peripheral blood monocytes from untreated patients with small cell carcinoma of the bronchus was compared with that of normal donors. Fc gamma receptor expression was found to be elevated in these patients in comparison with normal. In contrast HLA-DR antigen expression by patients' monocytes was somewhat depressed in comparison with normal. Continuous intravenous infusion of a total of 400 megaunits/m2 of human lymphoblastoid interferon-alpha (IFN-alpha) over a 5 day period markedly increased both monocyte HLA-DR antigen expression and Fc gamma receptor expression in comparison with that of untreated patients and normal donors. The initial increases declined somewhat but were still evident after 3 weeks of intermittent intramuscular IFN-alpha therapy.

Scheduled and unscheduled combination chemotherapy in the treatment of squamous cell lung cancer (cyclophosphamide, adriamycin, vincristine and bleomycin, with and without cis-platinum)

Fifty four patients with squamous cell lung cancer, treated with Cyclophosphamide (750 mg/m2), Adriamycin (50 mg/m2), Vincristine (1.5 mg/m2) and Bleomycin (30 mg) (CAVB) in a 2 day scheduled regime, showed an overall median survival time (MST) of 32 weeks (28 weeks for non-responders and 46.5 weeks for responders--a non-significant difference). The response rate was 24%, the median duration of response being 23 weeks. Bone marrow toxicity was not a major problem. A further 21 patients received the same drugs but in a single bolus (unscheduled regime). Comparison of their results with the 25 patients randomised to the scheduled regime showed no significant difference in MST or toxicity. The addition of Cis-platinum (50 mg/m2) to the unscheduled CAVB regime (CAVBP) in a further 22 patients did not result in an improvement either in survival or response, but added to the toxicity.

Role of venous sampling in locating a phaeochromocytoma

Selective venous sampling was performed in 31 patients in whom the diagnosis of phaeochromocytoma was suspected on clinical and biochemical grounds. Data from samples assayed for their adrenaline and noradrenaline content using a radioenzymatic technique were used to confirm or refute the suspected diagnosis. In 19 of the 31 patients a phaeochromocytoma was subsequently removed surgically, and the remaining 12 patients are now thought not to have tumours (mean follow up period: four years). Analysis of the assay data shows that selective venous sampling correctly identified the presence of a tumour in all 19 patients, and correctly excluded the diagnosis in 11 of the 12 remaining patients--an overall success rate of 97%. Success rates of 88% for arteriography and 84% for computed tomography were recorded, though these investigations were not performed in all patients. Ultrasound and intravenous urography were much less accurate. On the basis of this study a sequence of investigation is proposed for patients with a suspected phaeochromocytoma. Computed tomography occupies a central role in this sequence with venous sampling (and occasionally other techniques) being used only as complementary investigations when specific indications for their use exist.

Sporidesmin toxicity in rabbits: biochemical and morphological changes

The earliest lesion in rabbits dosed orally with 2 mg of sporidesmin per kg of body weight was necrosis of occasional hepatocytes 1 day after dosing. The most consistent lesion was a severe necrotizing cholangitis of medium and large-sized intrahepatic and extrahepatic bile ducts, first seen 2 days after dosing. Similar lesions were also present in the gall bladder of some rabbits. Expansion of portal triads with fibrous tissue and proliferating bile ductules progressed to pseudo-lobulation by 21 days. Other hepatic changes observed irregularly included large infarcts at the periphery of some lobes, and multiple small foci of coagulation necrosis in midzonal and periportal regions. Vascular necrosis and thrombosis, invariably adjacent to necrotic bile ducts, was presumably responsible for the hepatic necrosis. Serum cholesterol and total bilirubin concentrations and GGT activity reached peaks 15 days after dosing and were useful indicators of the severity of biliary lesions. Serum ID activity was the most useful indicator of hepatic necrosis following oral dosing with sporidesmin. The similarity between hepatobiliary lesions observed in sheep and rabbits with experimental sporidesmin toxicity suggests that the rabbit would be a useful model for studying methods of treatment and prevention of "facial eczema" in ruminants.

Human lymphoblastoid interferon in the treatment of small cell lung cancer

Ten patients with small cell lung cancer were treated with high dose human lymphoblastoid interferon (50-100 megaunits m-2) for 5 days, followed by low dose interferon (3 megaunits m-2) for 3 weeks. At the end of treatment, and one month later, there was no evidence of either complete or partial response. The treatment produced fever, anorexia and weight loss, with transient leucopenia and thrombocytopenia; there was evidence of a non-cholestatic elevation of serum alanine aminotransferase, with clinical deterioration in the condition of three patients presenting with hyponatraemia. A transient hypocalcaemia during high dose therapy was also noted. It seems that lymphoblastoid interferon as a single agent is unlikely to have a role in the treatment of small cell lung cancer, and that its administration as employed in this study is associated with considerable toxicity.

A dose-response study of I3-cis-retinoic acid in acne vulgaris

13-cis-retinoic acid has been used as a single agent in the treatment of seventy-six patients with previously unresponsive cystonodular acne. The study was carried out in a double-blind fashion using three doses of the drug. Ninety per cent of the patients responded with a 70% improvement in the acne severity. Sixty-six per cent of the patients experienced no further problems with their acne during follow-up. Side-effects were frequent. The 0.5 mg/kg b.w. dose is recommended for the initial course of treatment.

A double-blind study of the effects of 13-cis-retinoic acid on acne, sebum excretion rate and microbial population

Forty-eight acne patients were treated orally with 13-cis-retinoic acid in a double-blind dose response study. There was a marked clinical improvement with a concomitant reduction in sebum excretion rate (SER) and production rate of free fatty acids (FFA). Microbial numbers decreased significantly; the decrease in propionibacteria was greater than that of aerobic bacteria. The decline in micro-organisms occurred after the reduction in sebum and FFA production. This suggests that the effect of the drug upon micro-organisms is secondary to the change in sebum excretion but it is nevertheless an important factor in the resolution of the acne.