Prototype systems for rechargeable magnesium batteries

The thermodynamic properties of magnesium make it a natural choice for use as an anode material in rechargeable batteries, because it may provide a considerably higher energy density than the commonly used lead-acid and nickel-cadmium systems. Moreover, in contrast to lead and cadmium, magnesium is inexpensive, environmentally friendly and safe to handle. But the development of Mg batteries has been hindered by two problems. First, owing to the chemical activity of Mg, only solutions that neither donate nor accept protons are suitable as electrolytes; but most of these solutions allow the growth of passivating surface films, which inhibit any electrochemical reaction. Second, the choice of cathode materials has been limited by the difficulty of intercalating Mg ions in many hosts. Following previous studies of the electrochemistry of Mg electrodes in various non-aqueous solutions, and of a variety of intercalation electrodes, we have now developed rechargeable Mg battery systems that show promise for applications. The systems comprise electrolyte solutions based on Mg organohaloaluminate salts, and Mg(x)Mo3S4 cathodes, into which Mg ions can be intercalated reversibly, and with relatively fast kinetics. We expect that further improvements in the energy density will make these batteries a viable alternative to existing systems.

The neu oncogene: an erb-B-related gene encoding a 185,000-Mr tumour antigen

A series of rat neuro/glioblastomas all contain the same transforming gene (neu) which induces synthesis of a tumour antigen of relative molecular mass (Mr) 185,000 (p185). The neu oncogene bears homology to erb-B and the tumour antigen, p185, is serologically related to the epidermal growth factor (EGF) receptor. The two proteins, EGF receptor and p185 appear to be distinct, as they coexist in nontransformed Rat-1 cells.

The neu gene: an erbB-homologous gene distinct from and unlinked to the gene encoding the EGF receptor

The neu oncogene, identified in ethylnitrosourea-induced rat neuroglioblastomas, had strong homology with the erbB gene that encodes the epidermal growth factor receptor. This homology was limited to the region of erbB encoding the tyrosine kinase domain. It was concluded that the neu gene is a distinct novel gene, as it is not coamplified with sequences encoding the EGF receptor in the genome of the A431 tumor line and it maps to human chromosome 17.

Synergistic effects of cyclic AMP and nerve growth factor on neurite outgrowth and microtubule stability of PC12 cells

The outgrowth of neurites from rat PC12 cells stimulated by combined treatment of nerve growth factor (NGF) with cAMP is significantly more rapid and extensive than the outgrowth induced by either factor alone. We have compared the responses of PC12 cells under three different growth conditions, NGF alone, cAMP alone, and combined treatment, with respect to surface morphology, rapidity of neurite outgrowth, and stability of neurite microtubules, to understand the synergistic action of NGF and cAMP on PC12. Surface events at early times in these growth conditions varied, suggesting divergent pathways of action of NGF and cAMP. This suggestion is strongly supported by the finding that cells exposed to saturating levels of dibutyryl cAMP without substantial neurite outgrowth initiated neurites within 5 min of NGF. This response has been adopted as a convenient assay for NGF. Neurites that regenerated in the three growth conditions showed marked differences in stability to treatments that depolymerize microtubules. The results indicate that microtubules in cells treated with both NGF and cAMP are significantly more stable than in either growth factor alone. We suggest that a shift of the assembly equilibrium favoring tubulin assembly is a necessary prerequisite for the initiation of neurites by PC12.

Molecular cloning of the neu gene: absence of gross structural alteration in oncogenic alleles

The neu gene is distantly related to the erbB gene and encodes a cell surface protein that appears to function as a growth factor receptor. To study the mechanisms that caused the conversion of the normal neu gene to an oncogenic allele, we have isolated molecular clones of the neu oncogene as well as a clone of the corresponding protooncogene. The transforming neu oncogene and the proto-neu gene clones exhibit identical restriction enzyme patterns. Amplification of the proto-neu gene in NIH 3T3 cells by means of cotransfection with a dihydrofolate reductase gene resulted in methotrexate-resistant colonies that produce high levels of normal neu-encoded p185 protein. In contrast to cells carrying low levels of the oncogene-encoded protein, these cells appeared normal. The results suggest that the lesion that led to activation of the neu gene is a minor change in DNA sequence and is apparently located in the protein-encoding region of the gene.

Clonal variants of PC12 pheochromocytoma cells with altered response to nerve growth factor

We describe the isolation and characterization of clonal variants of PC12 pheochromocytoma cells which have been selected for loss of response to nerve growth factor (NGF). PC12 cells mutagenized with ethyl methanesulfonate were cultured in the presence of NGF, causing normal cells to cease proliferation and allowing the isolation of cell clones which do not show growth inhibition by NGF. Some but not all of these clones also failed to respond morphologically to NGF. Forty clones were isolated and characterized. Many exhibited altered morphologies of a variety of types, including clones with an NGF-independent formation of neurites and clones with various types of flattened epithelial morphology. Variant clones appeared to be mutants since their frequency of occurrence was increased by mutagen, the clones were generally phenotypically stable and no alteration in chromosomal composition was observed. Three clones lacked NGF receptor. Some clones responded morphologically to NGF (by forming neurites) without inhibition of proliferation. Several clones which did not otherwise respond to NGF nevertheless responded with transient membrane ruffling. Thus transient changes in cell surface morphology caused by NGF binding do not necessarily lead to subsequent responses. Several alternative hypotheses concerning the nature of the mutations induced are discussed.

Skin fibroblasts are the only source of nidogen during early basal lamina formation in vitro

The purpose of this study was to determine whether nidogen, the linkage protein of the basal lamina, is of epidermal or dermal origin. The development of the basal lamina was studied in an in vitro skin model. Preputial fibroblasts seeded onto a nylon mesh attached, proliferated, and developed a rich extracellular matrix (dermal model). Preputial keratinocytes were added to the dermal model to form a keratinocyte dermal model that ultrastructurally resembled in many respects human skin. Ultrastructural analysis revealed early stages of dermal development, including an incomplete basal lamina, aggregates of dermal filamentous material connecting to the lamina densa, bundles of 10-nm microfibrils, formation of premature hemidesmosomes, anchoring filaments, and anchoring fibrils. The cell origin of nidogen was determined in the dermal model and in the epidermal and dermal components of the keratinocyte dermal model. Specific antibodies and a cDNA probe for nidogen were used for immunofluorescence microscopy, Western and Northern blots, and for in situ hybridization studies. Our data show that fibroblasts are the only source of nidogen during early basal lamina formation. Although fibroblasts can synthesize nidogen and deposit it in the dermal matrix, no basal lamina will form unless they are recombined with keratinocytes. This suggests that the epidermis plays a major regulatory role in the production and assembly of nidogen into the basal lamina.

There is binding of collagen IV to beta 1 integrin during early skin basement membrane assembly

This study is concerned with the mechanism of basement membrane assembly in an in vitro 3-dimensional skin-culture system. Dermal fibroblasts alone can synthesize collagen IV, perlecan, and nidogen, but cannot assemble them into a basement membrane. When keratinocytes are added to the culture, however, linear assembly of collagen IV, perlecan, and nidogen is noted at the epidermo-dermal interface. Northern blots and in situ hybridization showed that perlecan and nidogen mRNAs derive exclusively from fibroblasts, while the alpha 2 (IV) collagen chain is expressed by both keratinocytes and fibroblasts, although the major source is in the mesenchyma (80%). Prior to the development of the lamina densa, collagen IV colocalizes with beta 1 integrins, most likely alpha 1 beta 1 and alpha 2 beta 1, which are known receptors for this collagen. Blocking experiments with the AIIB2 mAb (anti-beta 1 integrin subunit) and by peptide inhibition with the CB3(IV) collagen fragment disrupted the assembly of collagen IV. This study suggests that the initiation of basement-membrane formation involves binding of collagen IV molecules to keratinocyte cell-matrix integrins. These complexes act as nucleation sites for further polymerization of collagen IV molecules mostly derived from fibroblasts, by a process of self-assembly.

Antimicrobial stewardship and automated pharmacy technology improve antibiotic appropriateness for community-acquired pneumonia

BACKGROUND

 The Centers for Medicare and Medicaid Services' (CMS's) Hospital Inpatient Quality Reporting program includes the initial selection of antibiotics for adult community-acquired pneumonia (CAP) patients as a performance measure. A multidisciplinary team defined opportunities for improving performance in appropriate antibiotic use among CAP patients. The team consisted of personnel from the emergency department (ED), the antimicrobial stewardship program (infectious disease, pharmacy), and performance improvement.

DESIGN

 Quasi-experimental before-after study.

SETTING

 A large, urban, multicampus academic medical center. Interventions. Interventions included an algorithm for ED providers identifying appropriate antibiotic selections, development of a CAP kit consisting of appropriate antibiotics and dosing regimens bundled with the treatment algorithm, and preloading an automated ED medication dispensing and management system. A quality improvement methodology ("plan, do, check, act") was used to pilot stewardship interventions at one ED campus and later at a second ED campus.

RESULTS

 In the pilot ED, appropriate antibiotic selection for CAP improved from 54.9% before the intervention in 2008 to 93.4% after the intervention in 2011 (P = .001). Subsequently, in the second ED appropriate antibiotic regimens for CAP improved from 64.6% before the intervention in 2008 to 91.3% after the intervention in 2011 (P = .004)). The rates of another CMS measure, antibiotic administration within 6 hours, were not statistically different before and after the interventions. In an interrupted time series logistic regression analysis, the intervention was found to be significantly associated with the improved prescribing ([Formula: see text]).

DISCUSSION

 The combination of interdisciplinary teamwork, antibiotic stewardship, education, and information technology is associated with replicable and sustained prescribing improvements.

Antibodies to the ras gene product inhibit adenylate cyclase and accelerate progesterone-induced cell division in Xenopus laevis oocytes

Microinjection of monoclonal antibodies (lines 238, 172, and 259) directed against the ras gene product, p21, into Xenopus laevis oocytes accelerated progesterone-induced germinal vesicle breakdown. Antibody 238 had the greatest effect on the acceleration of progesterone-induced oocyte maturation, and this effect was correlated with in vitro inhibition of adenylate cyclase (EC 4.6.1.1) activity in a concentration-dependent manner. Inhibition of adenylate cyclase by antibody 238 was also measured in membranes prepared from oocytes pretreated with either cholera toxin or pertussis toxin. These results suggest a role for the ras gene product in the regulation of vertebrate cell adenylate cyclase activity.

Elderly patients discharged home from the emergency department with minor burns

OBJECTIVES

To describe the risk factors, etiology and referral patterns of elderly patients treated for minor burns in an urban emergency department (ED).

METHODS

A retrospective chart review was conducted of persons aged 65 years and older who were treated for a minor burn and discharged home from the ED. Medical records were reviewed for 77 burn patients that presented over a 6-year period.

RESULTS

Burn patients had significant co-morbid medical illness. The etiology of the burns was scalds (58%), contact (27%) and flame (12%). Sixty-eight percent of the burns were cooking related. Heating pads, curling irons or hot pipes accounted for the majority of contact burns. Three percent of burn patients were referred to a home care agency for a home safety evaluation at the time of discharge from the ED.

CONCLUSION

Cooking-related activities accounted for the majority of minor burns in this series. Common consumer items or environmental hazards were responsible for most contact burns. Elderly patients seen in the ED with minor burns were rarely referred to a home care agency.

Color vision defects in sickle cell anemia

The Farnsworth-Munsell 100-hue test was used to compare color vision in patients with sickle cell anemia, 20/20 visual acuity, and mild to severe peripheral retinopathy, but without posterior retinal vessel involvement, with matched normal controls. Patients with sickle cell anemia had significantly more blue-yellow and mixed color vision defects and significantly higher Farnsworth-Munsell 100-hue scores than did controls. There were no significant associations between color vision defects and the severity of peripheral retinal findings or the diameter of the foveal avascular zone. These results suggest that color vision defects may exist in patients with sickle cell anemia in the absence of ophthalmoscopic retinal changes in the posterior fundus.

Phototoxicity involving the ocular lens: in vivo and in vitro studies

Our laboratory has demonstrated the cataractogenic potential of UV radiation and several photosensitizing drugs in laboratory animals and in humans. We have utilized lens fluorescence measurements (which we have demonstrated to be a reliable marker for pre-cataractous and early cataractous changes), NMR pulse relaxation techniques, and our recently developed magnetic resonance imaging method to measure lens T2 values in the normal and UV exposed Degus lens (in vivo and in vitro) to detect pre-cataractous changes in the lens. These approaches will permit us to employ two parameters (increased non-tryptophan fluorescence and a decrease in T2 values) to monitor for such changes months before the lens opacities become manifest by conventional slit lamp examinations.

Severe periodic febrile myalgia in infancy due to carnitine palmitoyltransferase deficiency

A 7 1/2-yr-old girl suffered, since early infancy, severe recurrent myalgia during periodic attacks of fever, vomiting and pharyngitis. Neither myoglobinuria nor exercise-induced muscle pain was present. She was found to have carnitine palmitoyltransferase deficiency (CPTD) in leukocytes, fibroblasts and muscle. This case exemplifies the importance of looking for an associated metabolic etiology of recurrent febrile myalgia even in the absence of myoglobinuria.

In vivo non-invasive studies on the human lens

Progress in biophysical technology now permits us to monitor aging and precataractous changes in the human ocular lens in vivo as well as in vitro. We are employing two noninvasive techniques to measure changes in lens fluorescence and in one lens water compartment (T2) utilizing Scheimpflug lens fluorescence densitography and magnetic resonance imaging. These studies demonstrate age-related changes in the normal lens as reflected by enhanced fluorescence and longer T2 values. Precataractous changes can also be detected with this approach.