Pharmacological characterization of the inwardly-rectifying current in the smooth muscle cells of the rat bladder

1. In freshly-isolated single cells of the rat bladder detrusor, outwardly-rectifying and inwardly-rectifying membrane currents were identified by the whole-cell voltage-clamp technique. 2. The inwardly-rectifying current (IIR) exhibited features of a cation current permeable to both K+ and Na+ but it was unaffected by changes in extracellular Ca2+. It had an activation threshold close to -60 mV and an estimated reversal potential of -29 mV. 3. IIR activated slowly with a voltage-sensitive time-constant of 69 ms at -140 mV and 209 ms at -100 mV but did not exhibit time-dependent inactivation. 4. IIR was unaffected by tetraethylammonium (up to 20 mM) but it was reduced by extracellular Ba2+ (1 mM) and by extracellular Cs+ (1 mM). 5. IIR was reduced by terikalant (100 microM) and markedly inhibited by ciclazindol (100 microM) although at these concentrations, both agents also reduced outward currents. 6. IIR was inhibited by ZD7288 (10-100 microM) in a concentration-dependent manner. At concentrations up to 30 microM, ZD7288 did not reduce the magnitude of outward currents but these were inhibited by 100 microM ZD7288. 7. In strips of bladder detrusor, spontaneous mechanical activity was increased by ZD7288 (0.3-100 microM) and by ciclazindol (0.3-100 microM) but was unaffected by glibenclamide (1-10 microM). 8. It is concluded that IIR closely resembles the hyperpolarization-activated current Ih, previously described in the smooth muscle of rabbit jejunum and in a variety of other cell types. This current may play an important role in modulating detrusor excitability but this could not be confirmed using the inhibitors ZD7288 and ciclazindol.

Fluoro-Green and Fluoro-Red: two new fluorescent retrograde tracers with a number of unique properties

As a means of improving nerve tract-tracing in the peripheral and central nervous systems we experimented with two (retrograde) fluorescent emulsions, which we have tentatively named Fluoro-Green (FGr) and Fluoro-Red (FRe), and which we believe possess the following seven advantages: (1) they show little diffusion beyond the injection site; (2) their excitation/emission characteristics allow their use in double-tracing experiments; (3) they do not 'leak' from labeled cells; (4) their fluorescence is presented as large granules in the cytoplasm and its processes; (5) the fluorescence lasts for a sufficiently long time to permit repeated observation; (6) they may be used in combination with a wide variety of other neuroanatomical tracing methods; (7) they are economical, non-toxic and easy to utilize.

Retroviral transduction of hematopoietic progenitor cells with mutant p53 promotes survival and proliferation, modifies differentiation potential and inhibits apoptosis

Mutations in the p53 tumor suppressor gene have been shown to be associated with many human tumors and various leukemias and lymphomas. To examine whether constitutive overexpression of mutant p53 can effect transformation of normal hematopoietic cells, a mutant p53 gene was introduced into normal murine bone marrow hematopoietic cells by retroviral gene transfer. Compared to vector alone-infected cells, hematopoietic progenitor cells transduced with mutant p53 showed increased proliferative potential, enhanced cloning efficiencies and a modified differentiation pattern in vitro. In addition, mutant p53-transduced hematopoietic cells were more resistant to loss of viability and/or induction of apoptosis when cultured in a low concentration of serum or in the absence of both growth factors and serum. These effects occurred rapidly with no apparent contributory secondary events. No permanent cell lines or growth factor-independent cell strains were obtained. The results indicate that introduction of mutant p53 into normal hematopoietic cells in vitro contributes to transformation, including enhanced proliferative potential, modified differentiation and the suppression of apoptosis in these cells.

Energy transfer from carotenoid and FMO-protein in subcellular preparations from green sulfur bacteria. Spectroscopic characterization of an FMO-reaction center core complex at low temperature

The Fenna-Matthews-Olson (FMO)-protein and the FMO-reaction center (RC) core complex from the green sulfur bacterium Chlorobium tepidum were examined at 6 K by absorption and fluorescence spectroscopy. The absorption spectrum of the RC core complex was obtained by a subtraction method and found to have fiye peaks in the QY region, at 797, 808, 818, 834 and 837 nm. The efficiency of energy transfer from carotenoid to bacteriochlorophyll a in the RC core complex was 23% at 6 K, and from the FMO-protein to the core it was 35%. Energy transfer from the FMO-protein to the core complex was also measured in isolated membranes of Prosthecochloris aestuarii from the action spectra of charge separation. Again, a low efficiency of energy transfer was obtained, both at 6 K and at room temperature.

Highly ordered two-dimensional crystals of photosystem I reaction center from Synechococcus sp.: functional and structural analyses

The photosystem 1 reaction center complex from the thermophilic cyanobacterium Synechococcus sp. was isolated by Triton X-100 solubilization and fractional precipitation with polyethylene glycol. As shown by gel electrophoresis, the isolated complex was composed of the 83 kDa subunits A and B, and at least six other subunits with molecular mass below 20 kDa. Electron transfer from the primary electron donor P700 to the FA/FB centers was demonstrated by flash-induced absorption change of the isolated complex, while electron paramagnetic resonance (EPR) spectroscopy showed that the complex contained a full set of Fe-S clusters. Isolated complexes were reconstituted into two-dimensional crystals in the presence of phospholipids and different cations. The crystals were found to be active by flash-induced separation and EPR spectroscopy. Electron microscopy and digital image processing of negatively stained and frozen-hydrated specimens revealed orthorhombic crystals with unit cell dimensions a = 138 A, b = 145 A and p12(1) symmetry. A three-dimensional map was calculated for negatively stained crystals to 19 A resolution, whereas the projection map of frozen-hydrated crystals exhibited 8 A resolution.

Making information accessible: developing plain English discharge instructions

Discharge education has always been an important role for nurses working in acute care contexts. With the advent of case mix funding and subsequent trends towards early discharge from hospital, this educational role is assuming increasing importance. This paper addresses one aspect of a participatory action research study where a group of nurses, working in a paediatric orthopaedic ward, explored their discharge education practices and resources. The seemingly large number of post-discharge telephone queries received from parents of children treated on the ward prompted these nurses to question whether their discharge teaching practices were effective. Data collected on these telephone queries identified parental concerns regarding the care of their child at home in a plaster. This finding prompted group members to explore the ways that written information relating to care of the plaster at home might be implicated in the situation. An analysis of an existing 'home cast care' discharge instruction sheet raised issues concerning the content and language used in such resources. The paper describes the subsequent development of a plain English 'plaster care' discharge instruction sheet and argues the importance of using plain English in such resources.

Defining Home Health Care Nursing: Implications for Continuing Nursing Education

The purpose of this qualitative interpretivist study was to analyze and articulate the characteristics of nursing practice in the home health care context. Researchers sought to describe expert home health care nursing practice and how it developed. Twenty-one nurses, at various stages of practice development, were asked to write three clinical narratives describing their home health care practice. Data were analyzed to elicit themes and characteristics of nursing practice in the home health care context. Findings indicate that in the context of home health care, expert nursing practice develops along a continuum, until nurses can integrate physiological data with environmental and family data to provide seamless, intuitive, and highly complex nursing care. The results of this research can assist continuing education and staff development providers as they develop educational programs designed to facilitate professional development of new graduates and newly employed nurses in home health care.

Exposures and health effects: an evaluation of workers at a sodium azide production plant

Sodium azide is the principal gas-generating agent used to inflate automobile supplemental restraint systems, more commonly called airbags. Although sodium azide is known to affect the cardiovascular system by causing peripheral vasodilation, there is no published literature describing occupational exposures to sodium azide in the rapidly growing automobile airbag industry. In 1994-1995, the National Institute for Occupational Safety and Health (NIOSH) conducted a cross-sectional study of health complaints reported by sodium azide production workers at the only continuous sodium azide production facility in the United States. The NIOSH evaluation consisted of a plant industrial hygiene survey, a symptom questionnaire, ambulatory blood pressure monitoring, and blood azide analysis. Personal breathing zone air monitoring revealed exposures to sodium azide and hydrazoic acid (a reactant product) at levels greater than the NIOSH Recommended Exposure Limits (RELs). In some cases, exposures exceeded the REL despite the use of air-supplied respirators. The questionnaire revealed that most workers reported headache (10 of 11 [91%]), episodes of low blood pressure (9 of 11 [82%]), and palpitations (8 of 11 [73%]) occurring in the production areas within the 6 months preceding the study. Mild headache (4 of 11 [36%]) was the only symptom reported during our 24-hr medical survey. Ambulatory blood pressure monitoring revealed one asymptomatic employee with a drop in blood pressure (defined as a drop in systolic [at least 20 mm Hg] and diastolic [at least 10 mm Hg] blood pressure) during a period of exposure to sodium azide at a level five times the NIOSH REL. Improvements in plant engineering controls, increased attention to employee hygiene practices, and a more comprehensive respiratory protection program were recommendations made by NIOSH to reduce exposures at the plant. All facilities handling sodium azide should be aware of the potential toxicity of sodium azide and hydrazoic acid.

Duplicated proteasome subunit genes in Drosophila melanogaster encoding testes-specific isoforms

Using the previously cloned proteasome alpha-type subunit gene Pros28.1, we screened a Drosophila melanogaster genomic library using reduced stringency conditions to identify closely related genes. Two new genes, Pros28.1A (map position 92F) and Pros28.1B (map position 60D7), showing high sequence similarity to Pros28.1, were identified and characterized. Pros28.1A encodes a protein with 74% amino acid identity to PROS28.1, while the Pros28.1B gene product is 58% identical. The Pros28.1B gene has two introns, located in exactly analogous positions as the two introns in Pros28.1, while the Pros28.1A gene lacks introns. Northern blot analysis reveals that the two new genes are expressed only in males, during the pupal and adult stages. Tissue-specific patterns of expression were examined using transgenic flies carrying lacz-fusion reporter genes. This analysis revealed that both genes are expressed in germline cells during spermatogenesis, although their expression patterns differed. Pros28.1A expression is first detected at the primary spermatocyte stage and persists into the spermatid elongation phase of spermiogenesis, while Pros28.1B expression is prominent only during spermatid elongation. These genes represent the most striking example of cell-type-specific proteasome gene expression reported to date in any system and support the notion that there is structural and functional heterogeneity among proteasomes in metazoans.

Diet and psychological health

This article reviews research that suggests a relationship between diet and psychological symptoms. Mind-body dualism (as it relates to clinical practice) and the limited role of nutrition in mainstream biomedical training and treatment are discussed as background issues. Two areas of inquiry that have generated relevant research findings in this area are reviewed: (1) orthomolecular theory and vitamin deficiencies, and (2) clinical ecology/environmental medicine theory and the impact of "food allergies." Although clinical case reports and promising research findings have been reported, the impact of diet on psychological health is neither widely accepted nor integrated into mental health treatment methods. Ongoing research findings in brain biochemistry and psychoneuroimmunology point to communication pathways that can provide a clearer understanding of the links between nutritional intake, central nervous system and immune function, and psychological health status. These findings may lead to greater acceptance of dietary treatment approaches among health practitioners addressing psychological disorders.

8-Arylguanine adducts from arenediazonium ions and DNA

Arenediazonium ions (ArN2+) are genotoxic though the source of their genotoxicity is unknown. The present studies were undertaken to determine if reductive decomposition of ArN2+ to aryl radicals (Ar) in the presence of calf thymus DNA (ctDNA) or in cells results in the formation of DNA adducts. We found that when arenediazonium ions of the general structure p-X-ArN2+ (X = CH3, CH2OCH3, CH2OH) are allowed to react with ctDNA or incubated with cells under conditions that produce p-X-Ar, DNA adducts are formed with guanine. The structure of the adduct is the C8-substitution product derived from guanine and p-X-Ar. Formation of p-X-Ar was determined by ESR spin-trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO). The extent of C8-arylguanine adduction was measured by high performance liquid chromatography (HPLC) analysis of the DNA hydrosylate and comparison with authentic synthetic standards. The C8-arylguanine adducts observed to form may be important in regard to the genotoxicity of ArN2+, though other DNA adducts such as the N6-triazene of adenine or C8-aryladenine adducts can form. Finally, though the formation of C8-arylguanine adducts from arenediazonium ions has been proposed, this is the first report demonstrating their formation in DNA.

Type II diabetes: a treatment approach for the older patient

Noninsulin-dependent (type II) diabetes mellitus occurs most commonly with advancing age. The disease is accompanied by significant risk for morbidity of many organ systems and by risk for premature death. Morbidity and mortality are linked to persistent elevation of blood glucose concentration of even moderate degree. Through diet, weight reduction, exercise, and drug therapies, it is possible to bring blood glucose concentrations to close to normal levels and to reduce the likelihood of development or progression of diabetic complications.

Large outbreak of pertussis among young children in Chicago, 1993: investigation of potential contributing factors and estimation of vaccine effectiveness

BACKGROUND

An outbreak of pertussis from July, 1993, to April, 1994, in Chicago was investigated to identify potential contributing factors.

METHODS

Surveillance was enhanced to identify cases. Information from a vaccination coverage survey was used to define a retrospective cohort to estimate vaccine effectiveness of three or more doses of pertussis vaccine.

RESULTS

The median age of 218 reported cases was 8 months, 46% had Hispanic surnames and cases were clustered geographically. Vaccination status was known for 173 of 191 (91%) children younger than 6 years of age. Of these 173, 90 (52%) were younger than 7 months, and 35 (20%) children at least 7 months of age had received fewer than 3 doses of pertussis vaccine. Pertussis vaccine effectiveness was 76% (95% confidence interval, 29 to 92).

CONCLUSIONS

The limited ability of the current pertussis vaccination schedule to protect young infants accounted for 52% of cases, primary vaccine failure accounted for 28% of cases and failure to vaccinate children on time accounted for 20% of cases in young children. Low vaccine effectiveness did not appear to be a contributing factor.

X-linked mental retardation with thin habitus, osteoporosis, and kyphoscoliosis: linkage to Xp21.3-p22.12

We reevaluated a family previously described as having nonspecific X-linked mental retardation (XLMR) by Snyder and Robinson [1969: Clin Pediatr 8:669-674] (MIM 309583). Clinical and DNA studies were conducted on 17 relatives, including 6 males with mild-to-moderate mental retardation, 3 carrier females, and 8 normal males. In contrast to the normal appearance and minimal clinical findings reported 22 years ago, affected males were found to have a characteristic set of clinical findings. These developed gradually over the first 2 decades, and included thin body build with diminished muscle mass, osteoporosis and kyphoscoliosis, slight facial asymmetry with a prominent lower lip, nasal speech, high narrow or cleft plate, and long great toes. Carrier females were clinically normal. Multipoint linkage analysis indicated linkage to markers distal to the 3' end of DMD (DXS41 and DXS989), with a maximal lod score of 4.7. On the basis of these findings, this entity is redefined as XLMR syndrome.

Children's performance on "animal tests" of oddity: implications for cognitive processes required for tests of oddity and delayed nonmatch to sample

To investigate the ontogenesis of oddity learning, children (16 to 102 months of age) and adults were tested on two versions of the oddity task using non-verbal procedures originally developed for monkeys. On the standard, "one-part" or "simultaneous" oddity task (Experiment 1), young children (16 to 74 months of age) performed more poorly than older children (81-102 months of age) who were as proficient as adults. The delayed mastery of one-part oddity contrasts to mastery, at much younger ages (3 to 4 years of age) of a similar, but two-part task, delayed non-match to sample (DNMS) (Overman, 1990). In Experiment 2, those children from the first experiment who had difficulty in learning the one-part oddity task were tested on a two-part oddity task, and a subset of the subjects was retested on the one-part oddity task, and, finally, given verbal instructions for the one-part oddity task. The two-part oddity task was mastered significantly more rapidly than the previous one-part task; however, children's performance dropped significantly when tested on the one-part oddity task, and finally, children rapidly mastered the one-part oddity task when given verbal instructions. The data suggested that (a) children used different strategies to solve the different versions of the oddity task, (b) the solution for the two-part-task appeared earlier in life than the solution for the one-part task and did not involve the use of the concept of "oddity relations", and (c) in tasks in which stimuli are shown twice, behavior may come under control of the absolute properties of the exemplar stimulus via a simple "win-shift" pattern of behavior. In contrast, in tasks in which all stimuli are presented simultaneously, behavior may be controlled by stimulus relations, the analysis of which has a protracted ontogenetic development.

End stage liver disease in a 13-year old secondary to hepatitis C and hemochromatosis

Hepatic parenchymal iron deposition is a well-known complication of chronic hepatic inflammatory states. This can make the differential between chronic hepatitis and hereditary hemochromatosis difficult, however. The case of a 13-yr-old male with chronic hepatitis C and hereditary hemochromatosis resulting in end stage liver disease and the need for orthotopic liver transplantation is described. There has been no previously described case of the coexistence of these two diseases in a pediatric patient, resulting in end stage liver disease. The progression to cirrhosis in a patient of this age suggests a more rapid progression of the combined diseases than with either disease alone.

Increased expression of IL-1beta converting enzyme in hippocampus after ischemia: selective localization in microglia

Although the interleukin-1beta converting enzyme (ICE)/CED-3 family of proteases has been implicated recently in neuronal cell death in vitro and in ovo, the role of specific genes belonging to this family in cell death in the nervous system remains unknown. To address this question, we examined the in vivo expression of one of these genes, Ice, after global forebrain ischemia in gerbils. Using RT-PCR and Western immunoblot techniques, we detected an increase in the mRNA and protein expression of ICE in hippocampus during a period of 4 d after ischemia. Chromatin condensation was observed in CA1 neurons within 2 d after ischemia. Internucleosomal DNA fragmentation and apoptotic bodies were observed between 3 and 4 d after ischemia, a period during which CA1 neuronal death is maximal. In nonischemic brains, ICE-like immunoreactivity was relatively low in CA1 pyramidal neurons but high in scattered hippocampal interneurons. After ischemia, ICE-like immunoreactivity was not altered in these neurons. ICE-like immunoreactivity, however, was observed in microglial cells in the regions adjacent to the CA1 layer as early as 2 d after ischemic insult. The increase in ICE-like immunoreactivity was robust at 4 d after ischemia, a period that correlates with the DNA fragmentation observed in hippocampal homogenates of ischemic brains. These results provide the first evidence for the localization and induction of ICE expression in vivo after ischemia and suggest an indirect role for ICE in ischemic damage through mediation of an inflammatory response.

Pseudonyms for cancer registries

In order to conform to the rigid German legislation on data privacy and security we developed a new concept of data flow and data storage for population-based cancer registries. A special trusted office generates a pseudonym for each case by a cryptographic procedure. This office also handles the notification of cases and communicates with the reporting physicians. It passes pseudonymous records to the registration office for permanent storage. The registration office links the records according to the pseudonyms. Starting from a requirements analysis we show how to construct the pseudonyms; we then show that they meet the requirements. We discuss how the pseudonyms have to be protected by cryptographic and organizational means. A pilot study showed that the proposed procedure gives acceptable synonym and homonym error rates. The methods described are not restricted to cancer registration and may serve as a model for comparable applications in medical informatics.

Manipulation of the bacteriochlorophyll c homolog distribution in the green sulfur bacterium Chlorobium tepidum

We have shown that the green sulfur bacterium Chlorobium tepidum can be grown in batch culture supplemented with potentially toxic fatty alcohols without a major effect on the growth rate if the concentration of the alcohols is kept low either by programmed addition or by adding the alcohol as an inclusion complex with β-cyclodextrin. HPLC and GC analysis of pigment extracts from the supplemented cells showed that the fatty alcohols were incorporated into bacteriochlorophyll c as the esterifying alcohol. It was possible to change up to 43% of the naturally occurring farnesyl ester of bacteriochlorophyll c with the added alcohol. This change in the homolog composition had no effect on the spectral properties of the cells when farnesol was partially replaced by stearol, phytol or geranylgeraniol. However, with dodecanol we obtained a blue-shift of 6 nm of the Qy band of the bacteriochlorophyll c and a concomitant change in the fluorescence emission was observed. The possible significance of these findings is discussed in the light of current ideas about bacteriochlorophyll organization in the chlorosomes.

Injection drug use and risk of HIV transmission among homeless men with mental illness

OBJECTIVE

The high seroprevalence of HIV that has been reported among homeless individuals with mental illness indicates an urgent need to examine HIV risk behavior in this population.

METHOD

Injection drug use and sexual behavior were assessed in comprehensive interviews with 218 homeless mentally ill men in a New York City shelter. First, the proportion of men who had injected drugs was established. Then, among those who had injected drugs, the injection drug use behaviors associated with HIV transmission (i.e., whether they had ever engaged in high-risk behaviors and had ever engaged in risk-reduction behaviors) and their current sexual risk behaviors were examined.

RESULTS

Fifty (23%) of the 218 men had injected drugs. Among these 50, the great majority had engaged in high-risk behaviors, including sharing needles (66%) and using shooting galleries (64%). Few had engaged in risk-reduction behaviors, such as cleaning needles with bleach (22%) and using a needle exchange program (2%). In the past 6 months alone, the majority of the injection drug users had had unprotected sex with women (48%) or with men (10%).

CONCLUSIONS

This study documents a high lifetime prevalence of injection drug use in a group of homeless men with mental illness. The men who had injected drugs reported injection drug use and sexual behaviors with high risk of HIV transmission and gave scant evidence of risk-reduction behaviors. These individuals may fall between service systems and may be difficult to reach but, nonetheless, must be included in efforts to prevent transmission of HIV infection.

Treating leg ulcers: the latest techniques

Several advances in the care and treatment of leg ulcers are currently being developed, including laser therapy, ultrasound and the use of hyperbaric oxygen. In this article, the author describes the theory behind each therapy and the current level of research knowledge on the effectiveness and use of the methods.