Aphid species--vectors of plum pox virus.

Plum pox virus (PPV) is widely spread by natural vectors present in plum orchards. The efficiency of transmission is dependent on the frequency of the occurrence of vectors and the cultivar susceptibility to this pathogen. Having in view that PPV has a wide range of annual and multiannual host plants and vectors, there is great concern for obtaining PPV-resistant cultivars. This report deals with the following vectors: Hyalopterus pruni, Brachycaudus cardui, Brachycaudus helichrysi. Myzus persicae and Phorodon humuli aphids, and Aculus fockeni mite. Seven different cultivars of Prunus domestica were utilized. To assess the virus transmission rate, 50-100 individual vectors per tree were used. The treatment of the trees was performed every four weeks and then the disease symptoms were observed. PPV was transmitted by all vectors studied, the rate ranging in dependence on the susceptibility of cultivars used. Thus, in cvs. Centenar, Pescarus, d'Agen, Stanley and Tuleu Gras, the transmission rate ranged from 20% to 60%, while in susceptible cvs. Vanat romanesc and Vanat de Italia--from 40% to 80%.

Detection of plum pox virus by enzyme-linked immunosorbent assay in some apricot and peach varieties and hybrids in Romania.

Plum pox virus (PPV) is a potyvirus widely spread in many species of the Prunus genus such as plum, apricot, peach, sweet cherry and others. This potyvirus causes great damage to stone fruit trees in Romania and other European countries as Hungary, Italy, Czech Republic, France, Spain, Greece, Turkey, and Slovak Republic. The Research Station for Fruit Tree Growing Baneasa in Bucharest has realized many studies on the epidemiology and spread of PPV and also on the disease symptomatology and detection possibilities. The control of sharka disease by sanitary selection measures requires corresponding detection techniques. The aim of this study was to determine the presence or absence of PPV in some apricot and peach varieties and hybrids in 1995-1997 by the enzyme-linked immunosorbent assay (ELISA) and to verify if some of our biological materials evaluated as symptom-free under field conditions for many years are also virus-free and can be considered healthy.

Selective interaction model and photoreceptor cell membrane.

A mathematical model is proposed in order to describe, from the thermodynamic point of view, the changes in the photoreceptorcell membrane induced by light stimuli. The phenomenologicalbackground is the increase of the fly microvillar membrane ionicconductivity as a consequence of Ca(++-)Na(+) affinity modification under light action. On the basis of the analogywith the model of protein interaction in mixed solvents, themodel is focused on the selective interaction between ionchannels gates and two ionic ligands. Three possible theoretical cases are examined.

A comparative study of nutrient digestibility, kinetics of digestion and passage and rumen fermentation pattern in goats and sheep offered medium quality forages at the maintenance level of feeding.

The in vivo digestibility and the rates of degradation and passage of alfalfa hay (AH) and vetch straw (VS) were compared in three Granadina goats and three Segureña wethers fed at approximately maintenance level, using a change over design. The nylon bag technique was used to estimate the fractional rate of degradation of the feeds in the rumen. The fractional outflow rate of hay and straw particles was determined with chromium as a marker. No significant differences in the digestibility coefficients of nutrients between animal species were found. Nitrogen retention expressed as coefficients of both nitrogen intake and digested nitrogen was lower (P < 0.01) in goats than in sheep when VS was offered. There was no significant difference between goats and sheep in the effective degradability (measured at outflow rates in the range of 0.027 to 0.032 h-1) of dry matter (DM) for either forage. However, the effective degradabilities of the neutral detergent fibre (NDF) and crude protein (CP) of VS were lower (P < 0.01 and P < 0.001, respectively), in goats than in sheep. The degradation rates of DM, NDF and CP were not significantly different (P > 0.05) between goats and sheep. Also, the fractional rate of passage of particles from the rumen was not different (P = 0.056) between species, although there was a tendency for an increased outflow rate in goats. In a second experiment the effects of animal species, type of diet and frequency of feeding on rumen fermentation pattern were studied following a factorial design. Four goats and four wethers were used. They were randomly allocated to three dietary treatments: AH, VS or a 50:50 mixture of AH and VS (AH/VS). Rations were offered in two or three meals daily and samples of rumen content were obtained at 09.00, 11.00, 13.00, 15.00, 17.00 and 19.00 h. No difference in rumen pH was found between goats and sheep. Total volatile fatty acids and ammonia concentrations were higher (P < 0.001) in sheep than in goats. The molar proportions of acetate and isovalerate were higher (P < 0.01 and P < 0.001, respectively) in goats than in sheep, whereas the opposite was true for the molar proportion of n-butyrate. Feeding frequency had a slight effect on the rumen parameters measured. It is concluded that only minor differences in the digestive capacity and rumen activity of sheep and goats can be expected when they are fed on medium quality forages.

Some psychological reactions of rape victims.

This article delineates the psychological reactions of rape victims from a psychodynamic vantage point. Rape, an act of violence, results in psychic trauma. The authors attempt an understanding of the psychological sequelae of rape.

[Psychological preparation for surgery].

Recognition of the importance of psychological intervention for surgical patients is a relatively recent development. A range of diverse intervention techniques is now being used to relieve the distress of invasive procedures. We report results of a study in which surgical patients underwent psychological preparation. Intervention was based on a cognitive-behavioral program ("stress inoculation") built on the assumption that it is possible to "immunize" against stress just as it is possible to immunize by inoculation against measles or any other disease. This is done by exposing the individual to the agent (stress) in small doses in order to develop natural resistance. Coping mechanisms then develop so that when a real stressful situation is faced, its demands can be met satisfactorily. The experimental group of 20 patients had a 30-minute conversation with a psychologist in which they were taught various coping devices, including cognitive reappraisal of events surrounding the operation, calming self-talk and cognitive control through selective attention. The 20 in the control group met with the psychologist for the same length of time, but the content of the conversation was completely unrelated to the operation (attention-placebo group). The experimental group needed less post-surgical analgesia than the control group and coped better with the surgical situation in the opinion of the surgeons.

The influence of PTH, calcium gluconate and EDTA on the parotid saliva in the goat.

1. The role of exogenous parathyroid hormone (PTH) and stimulation or inhibition of endogenous hormone release, on the parotid gland of normal and thyroparathyroidectomized (t.x.p.t.x.) goats was studied. 2. The intravenous infusion of PTH and EDTA produced a transitory rise in saliva flow rate in intact animals. In t.x.p.t.x. goats the flow of saliva decreased transiently throughout the infusion. 3. The calcium levels in parotid saliva was unchanged throughout the infusion of PTH, EDTA, calcium gluconate both alone or with propranolol, in either intact or t.x.p.t.x. animals. 4. The parathyroid hormone infusion caused an increase in salivary phosphate concentration in both intact and operated goats. The effects of PTH upon the salivary flow and concentration of P are discussed.

Perhexiline increases calcium-activated force in skinned psoas fibres by raising calcium affinity of troponin-C.

We investigated the influence of the calcium-/calmodulin antagonist perhexiline on the calcium sensitivity of skinned muscle fibres from rabbit psoas muscle suspended in MgATP salt solution (pH 7.0; 20 degrees C). Perhexiline strongly sensitized the skinned fibres for calcium; thus the relationship between isometric force development and calcium ion concentration was shifted to the left in the presence of perhexiline. Similar results have been achieved with skinned fibres from pig cardiac (ventricular) muscle fibres. In skinned psoas we also determined the binding of Ca2+ to troponin-C by using the method developed by Güth and Potter (1987). Troponin-C labelled with DANZ (5-dimethyl-aminonaphthalene-2-sulfonyl aziridine) was incorporated into skinned fibres after previous extraction of troponin-C. The fluorescence signal (at 460 nm) as well as force increased when the calcium ion concentration rose to pCa 5.7. Addition of perhexiline increased this force and the fluorescence signal indicating that the increase in calcium responsiveness of the contractile apparatus was, at least partly, due to an increase in calcium occupancy of troponin-C.

Alteration of calcium sensitivity of skinned frog skeletal muscle fibres by inositol triphosphate and calmodulin antagonists.

We investigated the influence of inositol triphosphate (IP3), trifluoperazine (TFP), and perhexiline on the calcium sensitivity of freeze-dried frog semitendinosus muscle fibres. Further, the effect of IP3 on calcium release from the sarcoplasmic reticulum (SR) of frog semitendinosus fibres skinned by saponin was studied. IP3 decreased the calcium sensitivity of freeze-dried frog skeletal muscle fibres and failed to induce a calcium release from SR of saponin-skinned fibres. Freeze-dried frog skeletal muscle fibres were strongly sensitized for calcium by TFP and perhexiline.

The influence of sympathomimetic and sympatholytic agents on the salivary flow rate and concentration of Ca, P and protein in the parotid gland of the goat.

1. The role of the sympathetic autonomic division on the parotid gland of normal and thyroparathyroidectomized (t.x.p.t.x.) goats was studied. 2. The salivary flow rate and concentration of Ca, P and protein was tested during the intravenous infusions of sympathomimetic and sympatholytic agents. 3. The intravenous infusion of isoprenaline modified the salivary flow rate and the concentration of total protein. 4. None of the tested drugs modified significantly the concentration of Ca and P in the parotid saliva. 5. The results obtained in normal and t.x.p.t.x animals were similar; it seems that PTH is not involved in the observed changes.

Prognostically significant protein components of human breast cancer tissues.

Cryostat sections of clinicopathologically characterized breast cancer tissues were eluted with phosphate-buffered 0.9% sodium chloride solution, pH 7.2. The proteins were then characterized by polyacrylamide gel electrophoresis with and without prior treatment with sodium dodecyl sulfate. Approximately 65% of the brease cancer tissue eluates contained a prominent protein fraction with a molecular weight of 47,000 to 55,000 (p50). No such component was found in 15 of 17 eluates of benign breast tissue. Charge density studies disclosed that the p50 component included three populations of proteins that could be characterized according to the migration relative to gp55 derived from RIII murine mammary tumor virus, namely, fast (F-p50), intermediate (I-p50), and slow (S-p50). Prognostically favorable pathological characteristics, i.e., stage, nuclear grade, and lymphoreticuloendothelial responses, were proportionately most frequently found among S-p50 bbreast cancers and were least frequently found among F-p50 breast cancers. It appears that the S-p50 component acts in vivo as a prognostically significant immunogen. Further knowledge of the relationship between protein characteristics and clinicopathological features of human breast cancers would contribute to our understanding of mammary carcinogenesis and biological behavior.