Infection of tomato by the tomato yellow leaf curl virus: susceptibility to infection, symptom development, and accumulation of viral DNA

Symptom development in tomato plants following whitefly-mediated inoculation with tomato yellow leaf curl virus (TYLCV) was related to the occurrence of viral DNA using a specific DNA probe. Although disease symptoms were first observed 15 days post-inoculation, viral DNA could be detected 7 days earlier. TYLCV-DNA concentrations reached an optimum 4 days before symptoms appeared. The highest concentrations of TYLCV-DNA were found in rapidly growing tissues (shoot apex, young leaves, roots) and in the stems; the lowest concentrations were found in the older leaves and cotyledons. Plants were also inoculated on specific sites. Young leaves and apices were the best targets for virus inoculation. In these tissues, the viral DNA replicated at the site of inoculation and was transported first to the roots, then to the shoot apex and to the neighboring leaves and the flowers. Inoculation through the oldest leaves was inefficient.

Binding of porphyrin to human serum albumin. Structure-activity relationships

The equilibrium binding of hydroxyethyl vinyl deuteroporphyrin (HVD) and of irreversible porphyrin aggregates to human serum albumin was studied at the molecular level. This protein may function as an endogenous drug carrier for porphyrins in photodynamic therapy of tumours. HVD-protein binding studies revealed two types of binding sites, which are attributed to the two HVD isomers. The binding constant for the high-affinity isomer, 2.1 (+/- 0.3) x 10(8) M-1, is similar to that previously determined for protoporphyrin. At the same time the binding constant for the lower-affinity HVD isomer, 1.8(+/- 0.3) x 10(6) M-1, is similar to that previously determined for haematoporphyrin. Irreversible porphyrin aggregates were purified from the haematoporphyrin derivative and from Photofrin and are defined by spectral and chromatographic data. Gel-exclusion studies indicate that the dominant size of these aggregates is ten porphyrin monomeric units. The protein-binding constant of these aggregates is 1.7(+/- 0.2) x 10(5) M-1, with four binding sites per protein molecule. The distinction between the HVD isomers along the porphyrin-protein affinity sequence gives insight into the relationship of porphyrin structure to porphyrin-albumin binding. On the basis of this study an evaluation of human serum albumin as an endogenous carrier for porphyrins (at various aggregation states) in photodynamic therapy of tumours is presented.

Expression of the envelope antigen of dengue virus in vaccine strains of Salmonella

The envelope gene of dengue 4 virus (DEN) was cloned in a plasmid under the control of Escherichia coli expression signals. A clone that expressed 93% of the gene was found to be detrimental to the bacterial host. Another clone which carried only 76% of the E gene was found to be quite stable in vitro as well as in vivo. The killed recombinant bacteria induced antibodies in mice which recognized native DEN virus. Attenuated Salmonella typhimurium (SAL) strains carrying the DEN-E plasmid were tested for their efficacy as orally administered live vaccines. Protective immunization was assessed in a mouse model by immunizing three-week old BALB/c mice followed by challenge with DEN virus. It was found that these young mice were highly susceptible to the carrier SAL strains (M206 and aroA SL3261). Moreover, the SAL-infected mice were more susceptible to DEN virus challenge than control mice, suggesting that the SAL infection caused immunosuppression in these young mice.

Vasopressinergic innervation of the mouse suprachiasmatic nucleus: an immuno-electron microscopic analysis

Attempts are being made to unravel the local circuitry of the suprachiasmatic nucleus, with a view toward eventually correlating specific neuronal systems with circadian events. Hence, the vasopressinergic innervation of this nucleus in the laboratory mouse has been analyzed immunocytochemically at the light and electron microscopical levels. Monoclonal antineurophysin and polyclonal antivasopressin were used on aldehyde-fixed brains. Serial vibratome sections of the appropriate forebrain region were prepared for pre-embedding immunoperoxidase staining and/or postembedding immunogold labeling. Immunoreactive somata, processes, varicosities, and synaptic terminals were found throughout the suprachiasmatic nucleus, their ratio and density varying at different locations. The predominant type of vasopressinergic soma was ovoid to rounded (7-10 microns), containing secretory granules (85-120 nm), a large proportion of which were immunoreactive. Axon terminals, both nonimmunoreactive and immunoreactive, impinged upon vasopressinergic somata and processes, often displaying synaptic specializations. Vasopressinergic terminals, containing secretory granules and microvesicles, were found throughout the nucleus, particularly within the dorsomedial neuropil. These labeled terminals varied in size (0.4-3.4 microns 2) and shape, ranging from compact boutons to pleomorphic profiles, some deeply indented by postsynaptic spines, either dendritic or somatic. Approximately 65% of the vasopressin-containing terminals were axodendritic and 30% axosomatic; about 5% appeared to be axoaxonic. At least a quarter of all vasopressinergic synaptic terminals were axospinous. Other forms of interneuronal contact involving vasopressinergic elements (somata, dendrites) included extensive membrane to membrane appositional sites, and multiple puncta adhaerentia. The versatility of interconnections between vasopressin-containing neurons in the mouse suprachiasmatic nucleus suggests a highly active and coordinated network, which contributes substantially to local intranuclear circuitry. In addition, a dense efferent vasopressinergic output is directed dorsally towards the periventricular hypothalamus, where direct associations may be established with diverse hypothalamic neuroendocrine systems.

Distinct muscarinic receptor subtypes differentially modulate acetylcholine release from corticocerebral synaptosomes

The effect of McN-A-343 and oxotremorine on acetylcholine (ACh) release and choline (Ch) transport was studied in corticocerebral synaptosomes of the guinea pig. The synaptosomes were preloaded with [3H]Ch after treatment with the irreversible cholinesterase inhibitor, diisopropyl fluorophosphate, and then tested for their ability to release isotope-labeled ACh and Ch in the presence and absence of these agents. The kinetics of release were determined at the resting state (basal release) and in the presence of 50 mM K+. Under either condition, McN-A-343 enhanced the release of isotope-labeled ACh, whereas oxotremorine inhibited the K(+)-evoked release but had no effect on the basal release. The enhancing effect of McN-A-343 on basal ACh release was fully blocked by the selective M1 muscarinic antagonist, pirenzepine (100 nM). In contrast to its enhancing effect on ACh release, McN-A-343 potently inhibited Ch efflux as well as Ch influx. These effects were not blocked by atropine, a nonselective muscarinic antagonist. Oxotremorine had no effect on Ch transport. Binding studies showed that McN-A-343 was 3.6-fold more potent in displacing radiolabeled quinuclidinyl benzilate from cerebral cortex muscarinic receptors (mostly M1 subtype) than from cerebellar receptors (mostly M2 subtype), whereas oxotremorine was 2.6-fold more potent in the cerebellum. The displacements of radio-labeled pirenzepine and cis-dioxolane confirmed the M1 subtype preference of McN-A-343 and the M2 subtype preference of oxotremorine.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous absorption of physostigmine: optimization of delivery from a binary solvent by thermodynamic control

A series of binary vehicles was used to deliver physostigmine across dermatomed human skin. The vehicles consisted of isopropyl myristate (IPM) and isopropyl alcohol (IPA) mixed in various volume fractions. The kinetics of penetration is conveniently considered as the sum total of two contributing effects: a "push" process resulting from the excess free energy (delta EG) of the penetrant in the donor vehicle, and a "pull" process resulting from the effect of IPA and IPM on the skin barrier. The inverse ratio of the solubility of the drug in a given vehicle to that in pure IPA was used to estimate the relative delta EG, hence the relative "push" effect. The solubility of physostigmine was highest in pure IPA (delta = 11.5), lowest in pure IPM (delta = 8.5), and intermediate in their various mixtures. But the permeability coefficient (Kp) of physostigmine was highest when delivered from a 1:9 (v/v) solution of IPA:IPM and a calculated delta y = 8.8. A further increase in the volume fraction of IPA caused an opposite decrease in the Kp values of physostigmine. The "steady-state" flux (Jss) of IPA from the same vehicle was lowest at a volume fraction of 1:9 and highest at one of 1:1 IPA:IPM. Thus, the maximal physostigmine penetration enhancing effect of IPA occurs at the lowest flux of IPA found in the present series. This indicates that the "pull" process ascribed to the presence of IPA in the barrier membrane is not important enough to outweigh the decrease in delta EG of physostigmine following an increase in the volume fraction of IPA in the donor vehicle, or that an excess of IPA in the barrier is not conducive to further enhancement of physostigmine diffusivity across the barrier. Optimized percutaneous delivery of physostigmine is possible by thermodynamic control of the penetration process.

Antipsychotic effect of milieu in the acute treatment of schizophrenia

We studied 35 patients meeting DSM-III criteria for schizophrenia, paranoid or undifferentiated type, chronic with acute exacerbation. All were treated in hospital, 13 on a psychiatric intensive care unit, and 22 on an open ward. The former unit is a more structured and less stimulating one. We found those patients treated on that ward to show greater improvement in BPRS ratings during the first 2 days of hospitalization compared to the open-ward group, despite similar doses of medication being utilized. Additionally, this improvement was noted to occur among BPRS items comprising a psychotic subscale.

Desensitization of delayed-type hypersensitivity in mice: possible involvement of interleukin 2-dependent regulatory mechanisms in desensitized mice

The systemic injection of high doses of antigen into a previously immunized animal results in a state of transient anergy with respect to cell-mediated immune responses. This phenomenon is known as desensitization. The results presented here demonstrated that serum interleukin 2 (IL-2) activity was found transiently in desensitized mice at early stage (3 hr after the challenge). Subsequently, these mice could not develop in vivo (footpad swelling) and in vitro (lymphocyte proliferation) manifestations of cell-mediated immune responses 1 day after the challenge. Antigen-nonspecific and specific suppression of IL-2 production was observed in desensitized mice. The serum from 3 hr-desensitized mice containing endogenous IL-2 activity showed a marked suppressive effect on IL-2 production. Exposure of lymph node cells to IL-2 was capable of inhibiting IL-2 production in vitro. Additionally, in vivo administration of exogenous IL-2 into preimmunized mice led to the failure of development of footpad responses to antigen. These results suggest that IL-2-dependent regulatory mechanisms of T cell-mediated immune responses play an important role in the immunosuppression of desensitized mice.

A cytoplasmic activator of DNA replication is involved in signal transduction in antigen-specific T cell lines

Cytoplasmic extracts prepared from T cell lines undergoing antigen-specific, interleukin-2 (IL-2)-dependent proliferation were tested for their ability to induce DNA synthesis in isolated, quiescent nuclei. A tetanus toxoid (TET)-specific T cell line, established from peripheral blood of a normal human volunteer, was stimulated in the presence of relevant antigen and 1 unit/ml IL-2. Cytoplasmic extracts prepared from these cells were capable of inducing DNA synthesis in isolated, quiescent nuclei. The ability of cytoplasmic extracts to induce DNA synthesis in isolated, quiescent nuclei. The ability of cytoplasmic extracts to induce DNA synthesis in isolated nuclei correlated positively with the degree of proliferation induced in these cells. In contrast, incubation of this T cell line in the absence of antigen failed to induce proliferation and cytoplasmic extracts prepared from these cells induced little to no DNA synthesis in isolated, quiescent nuclei. The factor present in the cytoplasm of T cells stimulated with relevant antigen in the presence of IL-2 is similar, if not identical, to a factor which we have previously demonstrated in cytoplasmic extracts prepared from transformed lymphoblastoid cell lines and from mitogenically stimulated normal human peripheral blood mononuclear cells. This factor, which we have called activator of DNA replication (ADR) is a heat-labile protein, and is inactivated by treatment with protease inhibitors, including aprotinin. The ability of cytoplasmic extracts from T cells undergoing antigen-specific, IL-2-dependent proliferation to induce DNA synthesis in isolated, quiescent nuclei was markedly inhibited in the presence of aprotinin, providing strong evidence that a cytoplasmic activator of DNA replication, ADR, is involved in the signal transduction process for antigen-specific, IL-2-dependent T cell proliferation. ADR may represent a common intracellular mediator of DNA synthesis in activated and transformed lymphocytes.

Renal replacement therapy in the ICU: the role of continuous arteriovenous haemodialysis

Conventional haemodialysis is not available on all intensive care units (ICUs) and there are relatively few renally trained nurses able to run haemodialysis machines. Continuous arteriovenous haemodialysis provides effective renal replacement therapy for critically ill patients in the ICU. Unlike continuous arteriovenous haemofiltration it provides sufficient control over electrolyte, solute and water balance to obviate the need for additional treatment with intermittent conventional haemodialysis.

Weight gain associated with clozapine

Six of seven patients treated with clozapine gained 6-69 lb. Because of clozapine's anticipated availability in the United States, clinicians should be aware of this possible side effect, which, to the authors' knowledge, has not been reported previously.

Praziquantel treatment of porcine brain and muscle Taenia solium cysticercosis. 1. Radiological, physiological and histopathological studies

Porcine Taenia solium cysticercosis, recognized as a model of the human disease, was used to analyze the effect of the anthelminthic drug praziquantel on hosts and parasites. The drug (50 mg/kg daily) was given over 15 days in the feed of 13 cysticercotic and 9 control pigs. Changes in the number, size and appearance of brain parasites were seen by computerized tomography immediately after the last dose of praziquantel, although not all cysticerci had disappeared by day 47 following the end of the treatment. Muscle parasites became small and hyperdense shortly after treatment and disappeared from tomographic images afterwards. No alterations were found in EEGs or in brain-stem auditory and somatosensory evoked potentials. Muscle cysticerci showed increasing degrees of degeneration with time after treatment, and an augmented inflammatory reaction was concomitantly observed. In contrast, more heterogeneous results were obtained in parasites lodged in the brain, since viable cysts and less intense inflammatory reactions were found in the brain at different times after treatment. Physiological evaluation of the parasites showed that evagination was inhibited immediately after treatment and that oxygen consumption decreased with time. The results of this investigation suggest that praziquantel damages cysticerci and that the inflammatory reaction destroys and eliminates them.

Patients' satisfaction with care received in teaching settings

Voluntary psychiatric patients (N=118) on a teaching ward were asked to identify their medical personnel and rate their satisfaction with the care they received. The patients were proficient in distinguishing between psychiatrists, psychiatric residents, and medical students and were highly satisfied with the care they received. Patients over 35 were better at identifying residents than younger patients and also rated the quality of care pro-vided by psychiatrists more highly. Patients with adjustment reaction with depressed mood rated the quality of care provided by psychiatrists lower than did patients with major depression, bipolar affective disorder, or psychosis. Female patients rated their psychiatrists more highly than did male patients.

Morphologic changes in human carcinoma cells (A-431) stimulated by epidermal growth factor: effect of cholesterol and low-density lipoproteins on the ruffling response

Stimulation of A-431 carcinoma cells with epidermal growth factor (EGF) causes dramatic morphologic responses including ruffling, rounding, and bulk-phase pinocytosis. In attempts to explore the mechanisms responsible for changes in plasmalemma topography, we have investigated the effects of exogenous sterols thought to alter membrane fluidity. Light and scanning electron microscopy revealed a time- and concentration-dependent inhibition of ruffling (greater than 90%) by cholesterol. This effect could be duplicated by preincubation of the cells with comparable levels of low-density lipoproteins (LDL). EGF-stimulated bulk-phase endocytosis also is inhibited by treatment with cholesterol. No alteration of EGF binding, kinase stimulation, or internalization was detected in cells incubated in cholesterol-enriched medium (175 micrograms/ml in 0.5% ethanol), nor did cholesterol or LDL have any effect on EGF-stimulated rounding. Morphometry of electron micrographs from cholesterol-treated cells revealed a selective depletion of interdigitating lateral surface membrane that normally appears to be recruited to generate apical ruffles. Thus, the sterol inhibition of ruffling may be due to redistribution of plasmalemma rather than to changes in membrane viscosity. Together with previous observations, these data suggest that EGF-stimulated ruffling and bulk-phase pinocytosis are related phenomena, whereas EGF-stimulated cell rounding is an independent process.

Central catecholaminergic dysfunction and behavioural disorders following hypoxia in adult rats

Wistar male rats, 3-4 months old, were made to breathe for 6 h a sub-lethal hypoxic atmosphere consisting of 8% oxygen and 92% nitrogen. Following this treatment, these rats were subjected to a series of behavioral and biochemical tests starting 30 days and ending at about 180 days after the hypoxic insult. an age-matched control group was subjected to the same series of tests. The following findings were made at the time interval indicated, relative to controls: (1) At 30-35 days, diurnal (3 h) and nocturnal (12 h) locomotor activities decreased by about 25%. (2) At 40-45 days, amphetamine in the dose range of 0.25-1 mg/kg proved less effective in eliciting an increase in motor activity and stereotypic behavior. (3) At about 50 days, apomorphine in the dose range 0.25-0.5 mg/kg caused an increase in stereotypic behavior. (4) At 60-65 days, alpha-methyl-p-tyrosine at the dose of 50 mg/kg caused a more pronounced hypoactive syndrome and a slower rate of recovery of motor activity. (5) At 75-90 days, performance in the active avoidance test was inferior to that of controls. (6) At 180 days, and one hour after a dose of 200 mg/kg alpha-methyl-p-tyrosine, the turnover rates of hippocampal norepinephrine and caudate-putamen dopamine were much below control. One may tentatively conclude that one of the effects of hypoxia in adult rats is a lesion producing long-term behavioral disorders which are partly ascribed to dopaminergic and, possibly noradrenergic, dysfunction.

Does the acetyl group of aspirin contribute to the antiinflammatory efficacy of salicylic acid in the treatment of rheumatoid arthritis?

In a multicenter, double-blind, parallel-group study, 233 patients with classical or definite RA who demonstrated disease flare during a prestudy washout period were randomized to 12 weeks of treatment with either the nonacetylated salicylate, salsalate (salicylsalicylic acid), or aspirin. Of the 150 patients who completed the study, 83 received salsalate and 67 were treated with aspirin. Doses of the two drugs were calculated to provide equal amounts of bioavailable salicylic acid. The efficacy of salsalate and aspirin, as measured by all the usual variables, was equivalent but aspirin-treated patients had a higher incidence of severe gastrointestinal problems. Thus, this study demonstrated that the acetyl group of aspirin does not enhance the anti-inflammatory efficacy of salicylic acid in RA.

Health effects of long-term solvent exposure among women in blue-collar occupations

The relationship of solvent exposure to self-reported neurologic and somatic symptoms as well as neuropsychological performance was examined in a sample of 567 female blue collar workers who were members of the International Brotherhood of Electrical Workers (IBEW). Structured interviews were conducted at IBEW offices. Five solvent exposure categories were derived--never exposed, exposed prior to but not during the past year, exposed during the past year but not currently, currently exposed less than 50% of the time, and currently exposed more than 50% of the time. No differences among the groups on neuropsychological performance were found. On the other hand, heightened exposure was significantly related to depression, severe headaches, light-headedness, room spinning, appetite difficulties, funny taste in mouth, weakness/fatigue, rashes, and abdominal pain after controlling for the effects of seven risk factors (age, smoking, moderate-heavy alcohol consumption, severe obesity, history of physician-diagnosed chronic illness, working in a clean room, and exposure to other chemicals). These findings are consistent with Scandinavian studies of solvent-exposed male workers and point to the need for careful prospective research.