Determination of N-nitrosamines in food products intended for long term storage

The content of carcinogenous N-nitrosoamines (N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosopiperidine) was determined fluorimetrically (as NBD-amines) in preserved products, food concentrates, dried fruit and mushrooms. No N-nitrosoamines were found in the concentrates and dried products. The content of N-nitrosamines did not exceed 3 g/kg. In some samples its content reached 19 microgram/kg.     

Effects of film modeling on the reduction of anxiety-related behaviors in individuals varying in level of previous experience in the stress situation.

Evaluated the influence of film preparation on 80 4–11 yr old children undergoing 3 dental sessions (prophylaxis, examination, and restorative treatment) with respect to (a) peer modeling vs demonstration of procedures and (b) amount of information. It was found that, by evaluating self-report (Children's Fear Survey Schedule), and behavioral (Behavior Profile Rating Scale), and visceral-arousal indices in a factorial design, Ss exposed to a peer-model videotape presentation immediately preceding their own restorative treatment exhibited fewer disruptive behaviors and reported less apprehension than those watching a videotaped demonstration without a peer model. The modeling film elicited less heart rate activity in the Ss than the demonstration. 4–6 yr old Ss had lower self-reports of fear after viewing a more complete synopsis of what to expect, whereas the 8–21 yr old Ss had the lowest report of fears after viewing the peer model receiving a local anesthetic and brief intraoral examination. Ss with previous treatment experience benefitted most from viewing the peer model undergoing the entire restorative procedure or a demonstration of the administration of local anesthetic in the absence of a peer model. Ss with no prior experience were sensitized by being shown the demonstration. It is concluded that the age and previous experience of the viewer are important factors in determining childrens' fear-related behaviors after exposure to preparatory stimuli. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Negative association between reported life events and cardiovascular disease risk factors in employed men: the CORDIS Study. Cardiovascular Occupational Risk Factors Determination in Israel

This article reviews the literature data concerning the immunologic monitoring of animals and cell cultures exposed to mercury compounds. Mercury is present in nature as metallic mercury, mono- and bivalent inorganic compounds, and organic alkyl, aryl and alloxy-alkyl compounds. Methylmercury is most important in terms of environmental exposure while metallic mercury is the most common form to which workers are exposed. The database on immune function disturbances in human induced by mercury compounds is limited. Immunotoxicity assessment in animals, mainly in rodents, with subsequent extrapolation to man, is the basis of human risk assessment. The strength of in vitro immunotoxicity testing lies in studies aimed at unravelling mechanisms of immunotoxicity. These experimental investigations show clearly that mercury compounds can have immunomodulating activity. Mercuric chloride and methylmercury inhibit most of animal and human lymphocyte functions including proliferation, expression of cell activation markers on cell surface and cytokine production. These cells exhibit a greater sensitivity to the immunotoxic effects of methylmercury than to mercuric chloride. Repeated administration of mercuric chloride to rats, mice and rabbits can induce autoimmune response and a membranous nephropathy. In contrast, Lewis rats injected with mercuric chloride do not develop autoimmunity but exhibit immunosuppression. The immunosuppressive effects associated with exposure to chemical substances are often accompanied by increased susceptibility to challenge with infectious agents or tumour cells. Only few reports are available on animal studies of increased mortality connected with exposure to mercury compounds and challenge with infectious agents. It is difficult to establish a relationship between the observed immunomodulatory properties of mercury compounds and their possible carcinogenicity. In fact, the epidemiological studies performed so far failed to bring any conclusive evidence of carcinogenicity of mercury in animal experiments. The induction of renal tumours in male rodents by methylmercury was observed only.     

Direct evidence for anergy in T lymphocytes tolerized by oral administration of ovalbumin

The present study investigated bystander suppression, specific suppression and anergy as mechanisms for oral tolerance. Oral tolerance was induced in mice by a single gastric intubation of 20 mg ovalbumin (OVA) and was evaluated in vitro by the absence of T lymphocyte proliferative responses to OVA after priming by OVA-complete Freund's adjuvant (CFA). T lymphocyte unresponsiveness was antigen specific, systemic and was not affected by the vehicle used for immunization. T lymphocytes derived from tolerant popliteal lymph nodes (PLN) responded to an acetone precipitate (AP) of mycobacteria present in CFA; this response was not suppressed by co-culture with OVA, thereby arguing against a mechanism of bystander suppression in our system. Responses of PLN T lymphocytes derived from OVA-CFA primed, non-tolerant mice, or those of an OVA-specific T lymphocyte line, were not suppressed by PLN or spleen cells derived from OVA tolerant mice. These results excluded the possibility that oral tolerance was induced and maintained by a mechanism of specific suppression. At the cellular level, we found that OVA-tolerant T lymphocytes did not produce interleukin-2 (IL-2) nor express IL-2 receptor in response to OVA stimulation in vitro; both observations are indicative of a state of anergy. Incubation of OVA-tolerant PLN T lymphocytes together with murine recombinant IL-2 for 5 days, released anergic T lymphocytes and a concomitant OVA-specific proliferative response of CD4+ T cells was detected. Taken together, our experimental system excludes the involvement of bystander or specific suppression in the induction of oral tolerance to OVA, and provides direct evidence to show that oral tolerance results from specific T lymphocyte anergy.     

Reactive hyperglycaemia in patients with acute stroke

Initial and follow-up fasting serum glucose levels following acute stroke were evaluated retrospectively in 392 selected hospitalized patients. Transitory reactive hyperglycaemia was observed in a large number of patients (28% of the total series) without a history of diabetes prior to the acute cerebrovascular event. The data from this group suggest a possible relationship between the impairment of carbohydrate metabolism and the type and location of stroke since both the frequency and severity of the hyperglycaemic response were higher in patients with haemorrhagic stroke and brainstem infarction as compared with cerebral infarction. The incidence and degree of the reactive hyperglycaemia were also related to the severity of the acute stroke. There were more comatose patients in the group showing this phenomenon. Initial serum glucose levels in the latter group were higher in unconscious patients than in alert ones. In addition, hospital mortality was significantly higher in these patients. Transitory reactive increases of serum glucose levels were also observed in the majority of patients with a history of overt diabetes prior to the acute stroke. The hyperglycaemic reaction following acute stroke may be attributed to several underlying mechanisms. These include: a non-specific reaction to acute stress and tissue injury with the associated autonomic, hormonal and metabolic alterations; uncovering of underlying latent diabetes by the acute stroke; increased secretion of growth hormone due to stroke-induced hypothalamic dysfunction; and irritation of the glucose regulatory centres in the hypothalamus and brain stem by blood-laden cerebrospinal fluid or local ischaemia.     

Local spectrum analysis of field propagation in an anisotropic medium. Part I. Time-harmonic fields

The phase-space beam summation is a general analytical framework for local analysis and modeling of radiation from extended source distributions. In this formulation, the field is expressed as a superposition of beam propagators that emanate from all points in the source domain and in all directions. In this Part I of a two-part investigation, the theory is extended to include propagation in anisotropic medium characterized by a generic wave-number profile for time-harmonic fields; in a companion paper [J. Opt. Soc. Am. A 22, 1208 (2005)], the theory is extended to time-dependent fields. The propagation characteristics of the beam propagators in a homogeneous anisotropic medium are considered. With use of Gaussian windows for the local processing of either ordinary or extraordinary electromagnetic field distributions, the field is represented by a phase-space spectral distribution in which the propagating elements are Gaussian beams that are formulated by using Gaussian plane-wave spectral distributions over the extended source plane. By applying saddle-point asymptotics, we extract the Gaussian beam phenomenology in the anisotropic environment. The resulting field is parameterized in terms of the spatial evolution of the beam curvature, beam width, etc., which are mapped to local geometrical properties of the generic wave-number profile. The general results are applied to the special case of uniaxial crystal, and it is found that the asymptotics for the Gaussian beam propagators, as well as the physical phenomenology attached, perform remarkably well.     

Nasopharyngeal colonization in southern Israel with antibiotic-resistant pneumococci during the first 2 years of life: relation to serotypes likely to be included in pneumococcal conjugate vaccines

Nasopharyngeal carriage of Streptococcus pneumoniae was studied in 162 healthy infants at ages 2, 4, 6, 7, 12, and 13 months and in an additional 352 healthy children at ages 12, 15, 18, 21, and 24 months. Carriage was 26%, 39%, and 62% at 2, 12, and 24 months, respectively, and the respective resistance to > or = 1 antibiotic was 11%, 19%, and 27%. The presence of an older sibling or antibiotic treatment during the month preceding the culture was associated with carriage of resistant pneumococci in infants, whereas attendance at large day care centers was associated with carriage during the second year of life. Antibiotic resistance was detected in all 7 serotypes included in the candidate pediatric conjugate vaccines and was significantly more prevalent among vaccine-type pneumococci than among non-vaccine-type pneumococci. The use of conjugate vaccines may reduce the spread of resistant pneumococci.