Nutritional considerations in intravenous drug misusers: a review of the literature and current issues for dietitians

Poor nutritional status and inadequate dietary intake in intravenous drug misusers (IVDMs) is a well-recognized problem among those involved in their care. However, there are very few published studies to substantiate these observations. This paper provides a review of the current literature and outlines the aims of dietary advice for IVDMs.     

Promotion of mouthguards among amateur football players in Victoria

Abstract: Wearing mouthguards while playing contact sports reduces the prevalence and severity of orofacial injuries. We report on a 1991–92 promotion of mouthguard use among amateur football players in Melbourne. Four questionnaires were completed by players (1991 season: middle: n =638, 49 per cent response; late: n =770, 51 per cent; 1992: early: n =505, 26 per cent; late: n =698, 54 per cent), in four age groups (16–19, 20–23, 24–29, 30–44 years), about perceived mouthguard value and usage, injury experience, and awareness of a promotional message. Over the two seasons, mouthguard ownership and consistent wear increased and dental injuries decreased. Ownership of mouthguards increased among: 20–23 year olds and 30–44 year olds (13 and 16 per cent); managers, tradespersons, salespersons, labourers and the unemployed (14–19 per cent); residents of northern and western regions (12 and 13 per cent); those with 6 to 10 years of education (29 per cent); players in old boys' networks (13 per cent); and those with English as a first language (8 per cent). Consistent wear was high at matches (89 per cent) but low at training (13 per cent), owing to perceived lack of physical contact. Of dental injuries reported by 25–31 per cent, fractures predominated over luxations and avulsions. Fractures and avulsions were more common at matches than training; luxations predominated at training. When a mouthguard was not worn, the likelihood of a fractured or avulsed tooth was at least twice that when a mouthguard was worn. Some injuries occurred despite the wearing of mouthguards. The promotional message appeared effective in increasing mouthguard use; newspapers and football journals provided effective message locations for players, and ground signs and the electronic scoreboard for spectators.     

Insights from latent partition analysis into categories inherent in wellness-illness

How health–disease is perceived or conceptualized is important for nursing research There is increasing evidence that individual representations are important in constructing the experience of health–disease What is the personal saliency of health–disease for the individual? To explore the patterns of meaning inherent in health–disease, a card sort was undertaken among 15 healthy individuals and 15 individuals with chronic renal disease Both groups were given 28 cards to sort twice once for when they felt ‘well’ and again for when they felt ‘ill’ The theoretical basis underlying the items of the card sort was a model of wellness-illness being developed Latent partition analysis was used to cluster the concepts from each data set followed by multi-dimensional scaling to analyse the structure of the intercategory probability estimates A possible unidimensional pattern of meaning (harmony) emerged for the ‘well’ data and a two-dimensional pattern (disharmony and optimism) for the ‘ill’ data This represents a preliminary step in the development of a theoretical model that would permit assessment of the meaning of health–disease for the individual     

Chemotherapy of L1210 and L1210/ARA-C leukemia with 5-aza-2′-deoxycytidine and 3-deazauridine

Summary The in vitro and in vivo antineoplastic activity of 5-aza-2-deoxycytidine (5-AZA-dCyd) and 3-deazauridine (3-DU) against L1210 and L1210/ARA-C (resistant to cytosine arabinoside) leukemic cells were investigated. L1210/ARA-C cells were more sensitive to the inhibitory effects of 3-DU than L1210 cells. Deoxycytidine completely reversed the in vitro cytotoxic effects produced by 3-DU on L1210 cells, but not those produced in L1210/ARA-C cells. L1210/ARA-C cells, which are deficient in deoxycytidine kinase, were completely resistant to the antileukemic effects of 5-AZA-dCyd, whereas this analogue produced a very potent antileukemic effect against L1210 cells. To study the in vivo interaction of 5-AZA-dCyd and 3-DU with respect to drug resistance, mice were simultaneously injected i. v. with 10⁴ L1210 cells plus 10² L1210/ARA-C cells. A 9-h i. v. infusion of 5-AZA-dCyd (12.8 mg/kg) or 3-DU (186 mg/kg) produced an increase in life span of 56% and 26%, respectively. However, the sequential administration of 5-AZA-dCyd followed by 3-DU produced a 265% increase in life span and 7/10 longterm survivor, a very potent antileukemic effect. These results suggest that 3-DU is an excellent agent for use in combination chemotherapy to overcome drug resistance to the deoxycytidine analogue, 5-AZA-dCyd.This investigation was supported by grant MA-6356 from the Medical Research Council of Canada and by LEUCAN     

Hyper-recombination and mutator effects of the mms9-1, mms13-1, and mms21-1 mutations in Saccharomyces cerevisiae

Summary Spontaneous mitotic intragenic and intergenic recombination at various sites is enhanced 10 to 100 fold in the methyl methanesulfonate (MMS)-sensitive mutants mms9-1, mms13-1, and mms21-1 of Saccharomyces cerevisiae. All three mutants show elevated rates of spontaneous mutation. Sporulation is reduced in diploids homozygous for any of the three mutations, and a deficiency in meiotic recombination and meiotic chromosome segregation is observed. Pleiotropic effects on cell viability, growth rate, and radiation sensitivity, in combination with the alterations in recombination and mutagenesis displayed by mutant strains, suggest that the MMS9, MMS13, and MMS21 genes play important roles in DNA replication and/or genetic recombination.     

Different strains of Mycobacterium tuberculosis cause various spectrums of disease in the rabbit model of tuberculosis

The rabbit model of tuberculosis has been used historically to differentiate between Mycobacterium tuberculosis and Mycobacterium bovis based on their relative virulence in this animal host. M. tuberculosis infection in market rabbits is cleared over time, whereas infection with M. bovis results in chronic, progressive, cavitary disease leading to death. Because of the innate resistance of commercial rabbits to M. tuberculosis, 320 to 1,890 log-phase, actively growing inhaled bacilli were required to form one grossly visible pulmonary tubercle at 5 weeks. The range of inhaled doses required to make one tubercle allows us to determine the relative pathogenicities of different strains. Fewer inhaled organisms of the M. tuberculosis Erdman strain were required than of M. tuberculosis H37Rv to produce a visible lesion at 5 weeks. Furthermore, with the Erdman strain, only 7 of 15 rabbits had healed lesions at 16 to 18 weeks; among the other animals, two had chronic, progressive cavitary disease, a phenotype usually seen only with M. bovis infection. Genotypic investigation of the Erdman strain with an H37Rv-based microarray identified gene differences in the RD6 region. Southern blot and PCR structural genetic analysis showed significant differences between M. tuberculosis strains in this region. Correlation of the relative pathogenicity, including disease severity, in the rabbit model with the strain genotype may help identify stage-specific M. tuberculosis genes important in human disease.     

Thymus Ontogeny in Frogs: T-Cell Renewal at Metamorphosis

Metamorphosis in amphibians presents a unique problem for the developing immune system. Because tadpoles are free-living, they need an immune system to protect against potential pathogens. However, at metamorphosis, they acquire a variety of new adultspecific molecules to which the tadpole immune system must become tolerant. We hypothesized that Xenopus laevis tadpoles may avoid potentially destructive antiself responses by largely discarding the larval immune system at metamorphosis and acquiring a new one. By implanting triploid (3N) thymuses into diploid (2N) hosts, we examined the influx and expansion of host T-cell precursors in the donor thymus of normally metamorphosing and metamorphosis-inhibited frogs. We observed that donor thymocytes are replaced by host-derived cells during metamorphosis, but inhibition of metamorphosis does not prevent this exchange of cells. The implanted thymuses export T cells to the spleen. This donor-derived pool of cells declines after metamorphosis in normally developing frogs but is retained to a greater extent if metamorphosis is inhibited. These studies confirm previous observations of a metamorphosis-associated wave of expansion of T cells and demonstrate that it is not dependent on the relatively high concentrations of thyroid hormones required for metamorphosis. Although some larval T cells persist through metamorphosis, others may be destroyed or the larval population is significantly diluted by the expanding adult population.     

The magnitude and encephalogenic potential of autoimmune response to MOG is enhanced in MOG deficient mice

Myelin oligodendrocyte glycoprotein (MOG) is a minor component of central nervous system myelin presumably implicated in the pathogenesis of Multiple Sclerosis (MS). Immunization with MOG leads to the development of Experimental Autoimmune Encephalomyelitis (EAE), the experimental model of MS. It has been suggested that its encephalitogenic potential may be due to the lack of MOG self-immune tolerance. To clarify this, we have generated a MOG deficient mouse (MOG(-/-)) strain. Surprisingly, MOG(35-55)specific proliferation and Th1-type cytokine production were markedly enhanced in MOG(-/-)mice compared to wild type control. Furthermore, adoptive transfer of MOG(35-55)specific T cells, isolated from MOG deficient mice, into wild-type recipients resulted in the development of a more severe disease, indicating a high capacity of MOG(-/-)T cells to initiate effector responses. Interestingly, T cell reactivity to overlapping MOG peptides in MOG(-/-)mice did not reveal new potential immunodominant epitopes in H-2(b)mice. Taken together, our data suggests that MOG self-tolerance modulates the encephalitogenic potential of autoreactive MOG T cells in the periphery.     

Monoclonal anti-(T,G)-A—L antibodies: Characterization of fine specificity and idiotype expression

The technique of polyethylene glycol mediated cell fusion was used to establish 22 monoclonal cell lines secreting anti-(T,G)-A—L antibody. Cell lines were derived from C3H.SW and B10 mice and produced antibody with light chains and predominantly γ₁, heavy chains. Fine-specificity analysis demonstrated that 15 cell lines made antibodies that also recognize a determinant present on GAT, GT (9:1) and GT (1:1), whereas little, if any, serum antibody demonstrates this cross-reaction. Fourteen antibodies, derived from both B10 and C3H.SW mice, bear idiotypic determinants defined by Lewis anti-[B10 anti-(T,G)-A—L], but only two, both from C3H.SW mice, react with Lewis anti-[C3H.SW anti-(T,G)-A—L]. Adsorption studies indicate that no hybridoma tested bore the complete set of idiotypic determinants defined by either serum.