Cytogenetic studies in non-African Burkitt lymphoma

A particular translocation between chromosomes 8 and 14 has been found repeatedly in cytogenetic studies of Burkitt lymphoma, both of African and non-African origin. We report here our findings in cytogenetic studies of direct tumor preparations from 18 non-African Burkitt lymphoma patients, 9 of whom also had cell lines available for study. A t(8;14) was found in direct tumor material in 10 of the 18 patients. Seven of the 9 cell lines had a t(8;14). A total of 15 patients had either a t(8;14) or a 14q+ present in tumor material and/or cell lines. In addition, 8 patients had a peculiar marker chromosome 1. The t(8;14) was not found in every malignant cell and, where present, it was rarely the sole karyotypic abnormality. The relationship of the t(8;14) to the evolution of the tumor is discussed.     

Remote school gardens: exploring a cost‐effective and novel way to engage Australian Indigenous students in nutrition and health

Objective : This pilot study aimed to determine the feasibility of a novel, low‐cost program to get remote schools started in gardening and nutrition activities, for a lower cost than existing models, and without on‐the‐ground horticultural support. Methods : A multi‐site, mixed methods case study was undertaken, in which four remote schools were shipped gardening materials and a nutrition and cooking resource, and provided with horticultural support by phone and email. A support register and teacher surveys were used for four months of evaluation. Results : The study demonstrated that the program is feasible, and may be associated with an increase from baseline in student's time spent cooking, gardening and on related classroom activities. Conclusions : The program was delivered economically without the need for on‐the‐ground staff, in a manner that was acceptable to teachers. Implications : This model may have application in remote schools throughout Australia, where there is a need to alter health impacting behaviours in high‐risk populations. Lengthier program evaluation times and further resource development may be worth investigating in the future.     

Neural connectivity between the hypothalamic supramammillary nucleus and appetite‐ and motivation‐related regions of the rat brain

The supramammillary nucleus (SuM) has an emerging role in appetite control. We have shown that the rat SuM is activated during hunger or food anticipation, or by ghrelin administration. In the present study, we characterised the connectivity between the SuM and key appetite‐ and motivation‐related nuclei in the rat. In adult wild‐type rats, or rats expressing Cre recombinase under the control of the tyrosine hydroxylase (TH) promoter (TH‐Cre rats), we used c‐Fos immunohistochemistry to visualise and correlate the activation of medial SuM (SuMM) with activation in the lateral hypothalamic area (LH), the dorsomedial hypothalamus (DMH) or the ventral tegmental area (VTA) after voluntary consumption of a high‐sugar, high‐fat food. To determine neuroanatomical connectivity, we used retrograde and anterograde tracing methods to specifically investigate the neuronal inputs and outputs of the SuMM. After consumption of the food there were positive correlations between c‐Fos expression in the SuMM and the LH, DMH and VTA (P = 0.0001, 0.01 and 0.004). Using Fluoro‐Ruby as a retrograde tracer, we demonstrate the existence of inputs from the LH, DMH, VTA and ventromedial hypothalamus (VMH) to the SuMM. The SuMM showed reciprocal inputs to the LH and DMH, and we identified a TH‐positive output from SuMM to DMH. We co‐labelled retrogradely‐labelled sections for TH in the VMH, or for TH, orexin and melanin‐concentrating hormone in the LH and DMH. However, we did not observe any colocalisation of immunoreactivity with any retrogradely‐labelled cells. Viral mapping in TH‐Cre rats confirms the existence of a reciprocal SuMM‐DMH connection and shows that TH‐positive cells project from the SuMM and VTA to the lateral septal area and cingulate cortex, respectively. These data provide evidence for the connectivity of the SuMM to brain regions involved in appetite control, and form the foundation for functional and behavioural studies aiming to further characterise the brain circuitry controlling eating behaviours.     

The use of 7-amino actinomycin D in identifying apoptosis: simplicity of use and broad spectrum of application compared with other techniques

The detection and quantitation of apoptotic cells is becoming increasingly important in the investigation of the role of apoptosis in cellular proliferation and differentiation. The pathogenesis of hematologic disorders such as aplastic anemia and the development of neoplasia are believed to involve dysregulation of apoptosis. To quantitate accurately the proportion of apoptosis cells within different cell types of a heterogeneous cell population such as blood or bone marrow, a method is required that combines the analysis of large numbers of cells with concurrent immunophenotyping of cell surface antigens. In this study, we have evaluated such a method using the fluorescent DNA binding agent, 7-amino actinomycin D (7AAD), to stain three diverse human cell lines, induced to undergo apoptosis by three different stimuli. Flow cytometric analysis defines three populations on the basis of 7AAD fluorescence and forward light scatter. We have shown by cell sorting and subsequent morphological assessment and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling that the populations defined by 7AAD represent live, apoptotic, and late-apoptotic/dead cells. This method is quick, simple, reproducible, and cheap and will be a valuable tool in the investigation of the role of apoptosis in normal physiology and in disease states.     

The Radiosensitivity of Cultured Human and Mouse Keratinocytes

Summary

Clonogenic survival assays after γ-radiation in vitro were performed on freshly isolated and subcultured keratinocytes from mouse skin, mouse tongue and human skin.

Survival curves were constructed by fitting the data to a multi-target model of cell survival.

When subcultured, keratinocytes from all sites produced survival curves which showed a reduced shoulder region and an increased D₀ when compared with their freshly isolated counterparts.

Freshly isolated human skin keratinocytes were more radiosensitive than mouse keratinocytes from either skin or tongue.     

Efficacy of contact lens multipurpose solutions against serratia marcescens.

PURPOSE: To compare the susceptibilities of clinical isolates of Serratia marcescens and the standard ISO ATCC 13880 strain to five contact lens multipurpose disinfection solutions (MPDSs). METHODS: Five commercially available MPDSs, containing either a polymeric biguanide or polyquaternium, were tested using ISO/CD 14729 stand-alone test for contact lens care products against four ocular isolates of S. marcescens and the strain ATCC 13880. An average log reduction in bacterial numbers at the manufacturer's minimum recommended disinfection time was determined and compared with the criteria for stand-alone disinfection products for each MPDS against each bacterial strain. RESULTS: All the MPDSs tested met the stand-alone criteria of 3-log reduction of viable bacteria against the ATCC strain of S. marcescens. However, there was more variability in their ability to meet disinfection criteria when tested against the clinical isolates. Two of the clinical isolates were significantly more resistant to disinfection than was the recommended ISO strain (p < or = 0.034). Two of the polyquaternium-1-based disinfection solutions (solutions D and E, p < or = 0.005) were less effective overall than the other MPDSs against S. marcescens. CONCLUSIONS: The importance of strain selection for the testing of MPDSs is indicated, and the use of a single laboratory strain may be insufficient to provide assurance that the disinfection solution will be effective against clinical isolates. Furthermore, clinical isolates of S. marcescens may show increased resistance to disinfection with polyquaternium.     

Lysostaphin treatment of methicillin-resistant Staphylococcus aureus keratitis in the rabbit

PURPOSE: To determine the efficacy of lysostaphin treatment of methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MRSA) keratitis in a rabbit model. METHODS: The sensitivity to lysostaphin and vancomycin were compared for 34 MRSA and 12 methicillin-sensitive strains. Methicillin-resistant S. aureus strain 301 (MRSA 301) or a methicillin-sensitive strain of low virulence, ISP546, was intrastromally injected into rabbit corneas. Rabbit eyes were treated topically every 30 minutes from 4 to 9 or 10 to 15 hours postinfection with 0.28% lysostaphin or 5.0% vancomycin. Rabbits were killed and corneas were excised and cultured to determine the number of colony forming units (CFU) per cornea. RESULTS: Ninety percent minimal inhibitory concentrations were at least 19-fold lower for lysostaphin than for vancomycin. With early therapy (4 -9 hours postinfection) lysostaphin sterilized all MRSA 301-infected corneas, whereas untreated corneas contained 6.52 log CFU/cornea (P < or = 0.0001). Corneas infected with MRSA 301 and treated similarly with vancomycin retained 2.3 +/-0.85 log CFU/cornea, and none were sterile. When therapy was begun later (10-15 hours postinfection) the residual bacteria in lysostaphin-treated eyes were significantly less numerous than in vancomycin-treated eyes (0.58 +/- 0.34 vs. 5.83 +/- 0.16 log CFU/cornea, respectively; P < or = 0.0001). Three experiments were performed to demonstrate that lysostaphin penetrated the cornea to kill bacteria in vivo; lysostaphin-treated eyes were found to recover from infection, bacteria that did not cause epithelial defects (ISP546) were susceptible to lysostaphin, and inhibition of lysostaphin when harvesting corneas did not alter the observed therapeutic values of lysostaphin. CONCLUSIONS: Lysostaphin is very effective in treating keratitis mediated by methicillin-sensitive or methicillin-resistant S. aureus.     

Prevention of subglottic stenosis in neonatal ventilation

Mechanical ventilation of the newborn is now widely used in neonatal intensive care. The oro-tracheal route of intubation is simpler, but for long-term ventilation has been considered unstable. A method of fixation of oro-tracheal tubes is described which overcomes this instability. Five hundred consecutive ventilated infants were intubated by the oro-tracheal route and the tube was fixed by the method described. Of the 500 ventilated infants, 213 died without being extubated. Of the 287 survivors, 44 developed a degree of post-extubation stridor. No surviving infant developed clinical evidence of subglottic stenosis and in almost 200 postmortem examinations laryngeal narrowing was not identified. The method of oro-tracheal fixation described is stable and may reduce the incidence of subglottic stenosis.     

Dedicated small animal scanners: a new tool for drug development?

Nuclear imaging techniques can provide information about the time course of uptake, the spatial distribution, and the functional effects of a drug in the human body. Recently, PET has also acquired the potential to affect the drug development process during a very early stage, when a drug is undergoing animal testing. The development of dedicated small animal scanners with high resolution has made it possible to assess the time course of uptake of a drug within a single animal, providing that the drug is labelled with a positron-emitting isotope. Dedicated small animal scanners may therefore prove to be very useful, especially in those parts of the drug development process that require a longitudinal study design. However, in the case of receptor and enzyme studies, there may be pharmacological constraints and specific radioactivity of the radiopharmaceuticals may become an important issue. This paper will assess the potential and also the limitations of high-resolution PET in animal testing of therapeutic drugs.