Combined effect of gamma radiation and heating on the destruction of Listeria monocytogenes and Salmonella typhimurium in cook-chill roast beef and gravy

The effect of heating alone (60, 65 or 70 degrees C), heating after irradiation (0.8 kGy) and heating after irradiation and storage for 14 days at 2-3 degrees C on the destruction of Listeria monocytogenes and Salmonella typhimurium in artifically inoculated minced cook-chill roast beef and gravy was investigated. Inoculated minced roast beef samples (5 g) were heated in Stomacher bags completely immersed in a water bath at each of the test temperatures. Survivors were enumerated and D and z values were determined for each of the pathogens. Observed thermal D values for two strains of L. monocytogenes at 60, 65 and 70 degrees C in the absence of pre-irradiation were 90.0-97.5 s, 34.0-53.0 s and 22.4-28.0 s, respectively, whereas thermal D values after pre-irradiation were 44.0-46.4 s, 15.3-16.8 s and 5.5-7.8 s at 60, 65 and 70 degrees C, respectively. This reduction in D values provides evidence for radiation-induced heat-sensitisation in L. monocytogenes. There was some evidence of heat-sensitisation of S. typhimurium at 60 degrees C, but not at either 65 or 70 degrees C. The z value also decreased as a consequence of pre-irradiation to a dose of 0.8 kGy (11.0-12.7 degrees C). The radiation-induced heat-sensitivity in L. monocytogenes was found to persist for up to 2 weeks storage at 2-3 degrees C prior to heating. As cook-chill products are intended to be reheated prior to consumption the results of the present study suggest that any L. monocytogenes present in a cook-chill product would be more easily killed during reheating if it were to be treated with a low dose of gamma radiation during manufacture.     

Self-reported illness from chemical odors in young adults without clinical syndromes or occupational exposures

The present survey of young adult college students investigated the prevalence of self-reported illness from the smell of the five following common environmental chemicals (cacosmia): (1) pesticide, (2) automobile exhaust, (3) paint, (4) new carpet, and (5) perfume. Sixty-six percent of 643 students reported feeling ill from one or more of the five chemicals; 15% identified the smell of at least four chemicals as making them ill. Ratings of illness from pesticide correlated weakly but significantly with ratings for the largest number of individual symptoms (9 of 11); daytime tiredness and daytime grogginess both correlated at high levels of significance with illness ratings (on a 5-point scale) for four of the five chemicals. The most cacosmic group (CS) included significantly more women (79%) than the noncacosmic group (NS) (49%); women overall were more cacosmic than men (p < .001), even with the significant covariate of depression. Ratings of cacosmia correlated only weakly with scores for depression (r = 0.16), anxiety (r = 0.08), and trait shyness (r = 0.18) in the total sample. On stepwise multiple regression with cacosmia score as the dependent measure, shyness accounted for 5.8% of the variance, while depression, anxiety, sense of mastery, and repression did not enter the equation. Histories of physician-diagnosed hay fever, but not asthma, were more frequent in the CS (16%) than in the NS group (5%). Without the confounds of chronic illness or specific treatment programs, these data are similar to patterns described clinically for a subset of patients with multiple chemical sensitivities (MCS), including previous data on increased nasal resistance in MCS.(ABSTRACT TRUNCATED AT 250 WORDS)     

Activation status and function of the VLA-4 (alpha4beta1) integrin expressed on human melanoma cell lines

A highly sensitive microspectrophotometer was developed to measure spectral changes of oxyhemoglobin (oxy Hb) in single red blood cells (RBC) incubated with stimulated macrophages as a model of nitric oxide (NO) dependent cytotoxicity. Our microspectrophotometer, using a modified acousto-optic tunable filter (AOTF) and a 2-dimensional CCD array, allows fast spectrophotometric data acquisition. Human RBC treated with various concentrations of NO showed spectral changes due to the conversion of oxy Hb to methemoglobin (met Hb), in which the change in absorption differences at alpha (557 590 nm) and beta (542-525 nm) bands showed a linear relationship with the concentration of NO up to 100 microM. In contrast to highly diffusible NO, nitrite ions (NO2-) seem to enter RBC very slowly, resulting in negligible formation of met Hb in the presence of 5 mM glucose even during a prolonged incubation period. RBC were incubated with murine macrophages with and without lipopolysaccharide (LPS) in the presence of glucose for 24 and 40 h and subjected to the microspectrophotometric assay. The RBC incubated with LPS-stimulated macrophages showed significant changes in the spectrum due to NO-dependent conversion of oxy Hb to met Hb, which corresponded to the spectral changes of RBC treated with a several times higher concentration of NO than that in the culture medium. The trapping efficiency was calculated from the amounts of the NO released from macrophages and of the met Hb formed in the RBC, which gave a high efficiency (43%). The results suggest that RBC trap NO directly by cell cell interaction with macrophages. This spectrophotometric system is available for use with just a few drops of samples to study NO-specific cytotoxicity as a model of RBC without the use of any chemical reagent, in parallel with microscopic observations on changes of the cellular morphology under physiological conditions, such as membrane damage leading to hemolysis, adherence, and phagocytosis.     

Tear hyperosmolarity in renal dialysis patients asymptomatic for dry eye

Plasma levels of IGF-I, IGFBP-I and IGFBP-3 were measured before and during treatment with tamoxifen up to 19+ months in 34 post-menopausal patients with advanced breast cancer. In 28 patients, pro-IGF-IIE (IGF-IIE) levels were determined and IGFBP-3 was evaluated by immunoblot in 27 patients. Tamoxifen suppressed plasma levels of IGF-I by a mean value of 25.5%-37.7% at different times. This effect was fully developed after 1-2 months of treatment. IGF-IIE was decreased by a mean value of 7.7-23.2% at different time intervals during treatment with tamoxifen, but this effect was significant after long-term treatment (19 months +) only. Plasma IGFBP-I increased by a mean value varying between 48.6% and 190.1%. Tamoxifen had no significant effect on total IGFBP-3 levels. However, patients responding to treatment had a 28% reduction in fragmentation of IGFBP-3, while patients with progressive disease had a 36% increase in fragmentation. The difference between responders and non-responders was highly significant. These findings confirm and extend previous observations regarding the effects of treatment with tamoxifen on IGF-I and IGFBP-I. The finding that patients responding to tamoxifen achieve a reduction in the ratio of fragmented to intact IGFBP-3, while patients progressing on therapy experience an increase in the IGFBP-3 fragmentation ratio, suggest that the tumor burden influences IGFBP-3 protease activity in breast- cancer patients.     

The parallel process in clinical supervision with a schizophrenic client

The authors analyze a male nurse's account of how he experienced his interaction with a female schizophrenic client during sessions of systematic clinical supervision. Notes taken during 15 sessions were analyzed by means of open coding. The analysis revealed the importance of being aware of the parallel process that occurs among the client, the primary nurse, and the unit staff.     

Designing flexibility into memory systems

This paper describes two techniques which can be used to improve the flexibility of modern microcomputer systems. The first is the idea of a ‘processor-configured’ system, whereby the memory and peripheral interfaces may have their structure logically altered by a single from the processor card, so that they match the wordlength of the processor used. The technique may be applied to existing bus standards with a minimum of modification, and then allows 8-bit and 16-bit processor cards to be exchanged on the system with a minimum of inconvenience, and without compromising performance. The second technique, of ‘shadow-ROM’, is not new, but is not yet widely used in personal computer systems. The system described, using most significant address page switching, is a particularly flexible one.     

Iodine-131-anti-B1 radioimmunotherapy for B-cell lymphoma

PURPOSE: The CD20 B-lymphocyte surface antigen expressed by B-cell lymphomas is an attractive target for radioimmunotherapy, treatment using radiolabeled antibodies. We conducted a phase I dose-escalation trial to assess the toxicity, tumor targeting, and efficacy of nonmyeloablative doses of an anti-CD20 monoclonal antibody (anti-B1) labeled with iodine-131 (131I) in 34 patients with B-cell lymphoma who had failed chemotherapy. PATIENTS AND METHODS: Patients were first given tracelabeled doses of 131I-labeled anti-B1 (15 to 20 mg, 5 mCi) to assess radiolabeled antibody biodistribution, and then a radioimmunotherapeutic dose (15 to 20 mg) labeled with a quantity of 131I that would deliver a specified centigray dose of whole-body radiation predicted by the tracer dose. Whole-body radiation doses were escalated from 25 to 85 cGy in sequential groups of patients in 10-cGy increments. To evaluate if radiolabeled antibody biodistribution could be optimized, initial patients were given one or two additional tracer doses on successive weeks, each dose preceded by an infusion of 135 mg of unlabeled anti-B1 one week and 685 mg the next. The unlabeled antibody dose resulting in the most optimal tracer biodistribution was also given before the radioimmunotherapeutic dose. Later patients were given a single tracer dose and radioimmunotherapeutic dose preceded by infusion of 685 mg of unlabeled anti-B1. RESULTS: Treatment was well tolerated. Hematologic toxicity was dose-limiting, and 75 cGy was established as the maximally tolerated whole-body radiation dose. Twenty-eight patients received radioimmunotherapeutic doses of 34 to 161 mCi, resulting in complete remission in 14 patients and a partial response in eight. All 13 patients with low-grade lymphoma responded, and 10 achieved a complete remission. Six of eight patients with transformed lymphoma responded. Thirteen of 19 patients whose disease was resistant to their last course of chemotherapy and all patients with chemotherapy-sensitive disease responded. The median duration of complete remission exceeds 16.5 months. Six patients remain in complete remission 16 to 31 months after treatment. CONCLUSION: Nonmyeloablative radioimmunotherapy with 131I-anti-B1 is associated with a high rate of durable remissions in patients with B-cell lymphoma refractory to chemotherapy.