Suc-Phe-Leu-Phe-SBzl--a new substrate for functional study of Escherichia coli ATP-dependent Lon-proteinase and its modified forms

A new efficient substrate, Suc-Phe-Leu-Phe-SBzl, was proposed for studying the function of the Escherichia coli ATP-dependent Lon protease and its modified forms. The kinetic parameters of hydrolysis of the substrate were determined. The esterase activity of protease Lon was found to be nucleotide-regulated.     

Reaction of different cell populations in mouse thymus to a single gamma-irradiation

Acute care facilities are no longer viewed as the center of the health care network. Efforts to reduce hospital length of stay will continue to spur the growth of care delivered in homes. With the downsizing of many hospitals, the need for nurses in acute care settings will decline. Many acute care nurses are finding themselves seeking employment opportunities in home health care settings. The purpose of this study was to examine nurses' experiences when they change from hospital-based practice to home health care nursing. The qualitative mode of inquiry was used to conduct taped-recorded interviews of 25 baccalaureate-prepared nurses in a large metropolitan area. Stressors experienced by the nurses were identified as well as adaptations required to minimize role stress. Continuing education programs can provide information and skills needed to improve nurses' competencies to function in a health care system projected to be more community-based, which includes home health care.     

Use of tests for acidification of methyl-alpha-D-glucopyranoside and susceptibility to efrotomycin for differentiation of strains of Enterococcus and some related genera

A total of 107 Enterococcus strains, 10 Vagococcus fluvialis strains, and 8 Lactococcus garvieae strains were tested for acidification of methyl-alpha-D-glucopyranoside (MGP) and susceptibility to 100-microg efrotomycin (EFRO) disks. All 26 strains of Enterococcus casseliflavus, including 3 nonmotile and 2 nonpigmented strains, acidified MGP and were resistant to EFRO. All 22 strains of Enterococcus gallinarum, including 5 nonmotile strains, also acidified MGP and were resistant to EFRO. None of the 26 strains of Enterococcus faecium acidified MGP, and all were susceptible to EFRO. Although all 12 Enterococcus faecalis strains were also negative in the MGP test, they were resistant to EFRO. Other enterococcal strains gave variable results. All 10 strains of V. fluvialis and all 8 strains of L. garvieae gave positive and negative results, respectively, in the MGP test and were, respectively, resistant and susceptible to EFRO. These results indicate that tests of the production of acid from MGP and susceptibility to EFRO can be used as adjunct tests in the identification of typical and atypical strains of enterococci in the clinical microbiology laboratory.     

Parenting children with anorectal malformations: implications and experiences

Parents play a crucial role in the life of a child suffering from an anorectal malformation (ARM), since their guidance contributes to the degree to which the child learns to cope with his or her disability. We investigated whether they experience stress in parenting such a child and also attempted to identify somatic or behavioral characteristics in the child that influence the stress of parenting. The parents of 109 children (69 males, 40 females; median age 5.9 years, range 1-18 years) with an ARM (58 low, 10 intermediate, 41 high) were studied. The Nijmegen Questionnaire on Child-rearing Situations (NQCS) was used to investigate the existing parenting situation. Behavioral characteristics of the children were studied by means of the Child Behaviour Checklist (CBCL) and the Teacher Report Form (TRF). In a semi-structured interview, we investigated how parents experienced the implications of the disability in everyday life with their child. Our study showed that as far as the perception of parenting stress is concerned, parents of children with an ARM do not differ from those with healthy primary-school children. Within the group of parents with ARM-afflicted children, the parents of older, incontinent children experienced relatively more stress, especially when the child concerned was male. With regard to the children's behavior, the parents and teachers under investigation did not report a higher than normal incidence of deviant behavior. However, when individual parents observed difficult behavior in their child, they found it harder to deal with than the incontinence for feces. Regarding the implications of the disorder for their everyday lives, parents were concerned and indicated a need for specific counselling. We conclude that having a child with a somatic affliction, in this case an ARM, does not automatically imply that the parents experience child-rearing problems. However, certain groups of parents are more at risk, i.e., parents with older, incontinent sons and parents with children exhibiting behavioral problems. In addition, our study shows that parents do have difficulties in coping with the implications of the disorder and express a need for support. We feel that patient care can be improved if aid is tailored to these specific problems.     

More positive or less negative? Trends in research on adjustment of families rearing children with developmental disabilities

Breast cancer is one of the most common forms of cancer observed in women, and endogenous estrogen is thought to play a major role in its development. Because of this, any conditions or exposures which enhance estrogenic responses would result in an increased risk for breast cancer. The role of xenoestrogenic compounds, such as DDT, in the etiology of breast cancer is still very controversial. In the following paper we discuss recently-published observations by ourselves and others which indicate that xenoestrogens may play a significant role in the development of breast cancer. Specifically, we hypothesize that during periods of high growth rates and during breast development the sensitivity of breast cells to estrogenic compounds is sufficiently great for xenoestrogens to significantly enhance risk for breast cancer.     

Epstein-Barr virus uses different complexes of glycoproteins gH and gL to infect B lymphocytes and epithelial cells

The Epstein-Barr virus (EBV) gH-gL complex includes a third glycoprotein, gp42. gp42 binds to HLA class II on the surfaces of B lymphocytes, and this interaction is essential for infection of the B cell. We report here that, in contrast, gp42 is dispensable for infection of epithelial cell line SVKCR2. A soluble form of gp42, gp42.Fc, can, however, inhibit infection of both cell types. Soluble gp42 can interact with EBV gH and gL and can rescue the ability of virus lacking gp42 to transform B cells, suggesting that a gH-gL-gp42.Fc complex can be formed by extrinsic addition of the soluble protein. Truncated forms of gp42.Fc that retain the ability to bind HLA class II but that cannot interact with gH and gL still inhibit B-cell infection by wild-type virus but cannot inhibit infection of SVKCR2 cells or rescue the ability of recombinant gp42-negative virus to transform B cells. An analysis of wild-type virions indicates the presence of more gH and gL than gp42. To explain these results, we describe a model in which wild-type EBV virions are proposed to contain two types of gH-gL complexes, one that includes gp42 and one that does not. We further propose that these two forms of the complex have mutually exclusive abilities to mediate the infection of B cells and epithelial cells. Conversion of one to the other concurrently alters the ability of virus to infect each cell type. The model also suggests that epithelial cells may express a molecule that serves the same cofactor function for this cell type as HLA class II does for B cells and that the gH-gL complex interacts directly with this putative epithelial cofactor.     

BiP maintains the permeability barrier of the ER membrane by sealing the lumenal end of the translocon pore before and early in translocation

Secretory proteins are cotranslationally translocated across the mammalian ER membrane through an aqueous pore in the translocon while the permeability barrier is maintained by a tight ribosome-membrane junction. The lumenal end of the pore is also blocked early in translocation. Extraction of soluble lumenal proteins from microsomes and reconstitution with purified proteins demonstrate, by fluorescence collisional quenching, that BiP seals the lumenal end of this pore. BiP also seals translocons that are assembled but are not engaged in translocation. These ribosome-free translocons have smaller pores (9-15 A diameter versus 40-60 A in functioning translocons) and are generated when ribosomes dissociate from functioning translocons with large pores. BiP therefore maintains the permeability barrier by sealing both nontranslocating and newly targeted translocons.     

1,4-Cyclohexanecarboxylates: potent and selective inhibitors of phosophodiesterase 4 for the treatment of asthma

Evaluation of a variety of PDE4 inhibitors in a series of cellular and in vivo assays suggested a strategy to improve the therapeutic index of PDE4 inhibitors by increasing their selectivity for the ability to inhibit PDE4 catalytic activity versus the ability to compete for high affinity [3H]rolipram-binding sites in the central nervous system. Use of this strategy led ultimately to the identification of cis-4-cyano-4-[3-(cyclopentyloxy)-4-methoxyphenyl]cyclohexane-1-carboxyl ic acid (1, SB 207499, Ariflo), a potent second-generation inhibitor of PDE4 with a decreased potential for side effects versus the archetypic first generation inhibitor, (R)-rolipram.