Effects of oxygen on nodule physiology and expression of nodulins in alfalfa

Early nodulin 2 (ENOD2) transcripts and protein are specifically found in the inner cortex of legume nodules, a location that coincides with the site of a barrier to O2 diffusion. The extracellular glycoprotein that binds the monoclonal antibody MAC236 has also been localized to this site. Thus, it has been proposed that these proteins function in the regulation of nodule permeability to O2 diffusion. It would then be expected that the levels of ENOD2 mRNA/protein and MAC236 antigen would differ in nodules with different permeabilities to O2. We examined the expression of ENOD2 and other nodule-expressed genes in Rhizobium meliloti-induced alfalfa nodules grown under 8, 20, or 50% O2. Although there was a change in the amount of MAC236 glycoprotein, the levels of ENOD2 mRNA and protein did not differ significantly among nodules grown at the different [O2], suggesting that neither ENOD2 transcription nor synthesis is involved in the long-term regulation of nodule permeability. Moreover, although nodules from all treatments reduced their permeability to O2 as the partial pressure of O2 (pO2) was increased to 100%, the levels of extractable ENOD2 and MAC236 proteins did not differ from those measured at the growth pO2, further suggesting that if these proteins are involved in a short-term regulation of the diffusion barrier, they must be involved in a way that does not require increased transcription or protein synthesis.

Effects of allopurinol on free-radical-induced reduction of the proliferation of retinal pigment epithelial cells

PURPOSE

To investigate the effects of allopurinol on free-radical-induced reduction of growth of retinal pigment epithelial (RPE) cells.

METHODS

Bovine RPE cells were seeded at a density of 1 x 10(5) cells/Petri dish (60 x 15 mm) containing 4 ml MEM-Earle plus 15% FCS plus antibiotics. Twenty-four hours after seeding, cultures were exposed to a free radical generating system hypoxanthine(HX)/xanthine oxidase (XO) (HX: 0.1 micromol/l; XO: 700 microU/ml) for 10 or 60 min. Thereafter, the cells were washed. After washing the cells, allopurinol was added at 500 or 1000 micromol. To evaluate the effect of the radical generating system one group was not washed after treatment ('no wash'). The cultures were divided into eight groups: (1) no treatment (control); (2) HX/XO, no wash; (3,4) HX/XO, washed after 10 or 60 min; (5,6) HX/XO, washed after 10 or 60 min, application of 500 micromol of allopurinol; (7,8) HX/XO, washed after 10 or 60 min, application of 1000 micromol of allopurinol. Cell counts were carried out 96 h post-seeding. The values are expressed as means +/- SE.

RESULTS

After 72 h (HX/XO, no wash), the radical generating system resulted in a significant decrease in cell growth as compared to controls. When being eliminated after 10 or 60 min, the radical generating system also led to significant decrease in the values as compared to controls. Allopurinol treatment: All therapy (scavenger) groups (4,5) were significantly different from the respective control group; following exposition to the radical generating system for 60 min, allopurinol showed significantly higher values when given at 1000 micromol as compared to 500 micromol.

CONCLUSIONS

The results demonstrate that allopurinol, when given at a scavenger dose (500-1000 micromol), can prevent free-radical-induced cell damage and stop chain reactions. Thus, the possible beneficial value of allopurinol on diseases with involvement of oxidative tissue damage, such as age-related macular degeneration, should be investigated further.

The simultaneous measurement of low rates of CO2 and O2 exchange in biological systems

An instrument for measuring low rates of biological O2 exchange using an open-flow gas analysis system is described. A novel differential O2 sensor that is capable of measuring as little as 0.4 Pa O2 against a back-ground of ambient air (20,900 Pa O2), yet has a dynamic range of +/- 2000 Pa O2 (i.e., +/- ca. 2% O2) is described. Baseline drift was typically less than 0.025 Pa min-1. The differential O2 sensor was incorporated into a respiratory quotient/photosynthetic quotient analyzer that contained other environmental sensors for atmospheric pressure, absolute O2 and CO2 concentration, temperature of the differential O2 sensor block, and differential pressure between reference and sample streams. Protocols for how these sensors can be used to calibrate the differential O2 sensor and to improve its stability with time are described. Together, the differential O2 sensor, the environmental sensors, and the simple calibration techniques allow for simultaneous, noninvasive, and accurate measurements of O2 and CO2 exchange in tissues with metabolic rates as low as about 0.1 mumol O2 or CO2 h-1. Example data are provided in which O2 differentials of 3 to 41 Pa O2 were measured in an open-flow system.

Importance of decreased heart rate in predicting transplant coronary artery disease

Studies in animals and humans have demonstrated that an increased heart rate is a predictor for the development of coronary atherosclerosis and overall cardiovascular mortality. In contrast, we have previously reported that the need for pacemaker implantation because of bradycardia in heart transplant recipients is associated with an increased prevalence of transplant coronary artery disease (TxCAD). Hence, the relevance of changes in heart rate to the development of TxCAD remains unclear. Intra-coronary ultrasound examinations (ICUS) were therefore analyzed in 130 heart transplant recipients (age 50 +/- 11 yr) studied at annual evaluations (3.7 +/- 3.0 yr after transplantation). Quantitative ultrasound measurements were obtained by calculating mean coronary artery intimal thickness (MIT) obtained by examination of the left anterior descending artery. The presence of TxCAD was defined as MIT > 0.3 mm. Resting heart rates (HR) were recorded with the patients in the supine position during routine echocardiography. Based on HR recordings, two groups were defined: group 1, HR below; or group 2, HR above the median. TxCAD was detected in 40% of the ICUS studies overall. The prevalence of TxCAD was higher in group 1 (49%) compared with group 2 (33%), p < 0.05. There was no significant difference in donor ischemic time or donor gender, recipient age, gender, body weight, CMV status, creatinine, total cholesterol, use of lipid lowering drugs or diltiazem. Donor age and use of beta-blockers were higher in group 1 compared with group 2 (29 +/- 10 vs. 25 +/- 9 yr, and 15% vs. 5%, for donor age and beta-blocker use, respectively). By multivariate regression analysis only donor age and years after transplantation were independently correlated with TxCAD. After excluding patients taking beta-blockers and diltiazem, the prevalence of CAD was still higher in group 1 (50%) vs. group 2 (34%). In conclusion, transplant coronary artery disease is more prevalent in patients with lower, rather than higher, heart rates. The reason for this is unclear, but may reflect impaired blood flow to the sinoatrial node.

Ultraviolet vision and band-colour preferences in female zebra finches, Taeniopygia guttata

Zebra finches have previously been found to have preferences for particular colours of both natural and artificial traits among opposite sex conspecifics. For example, in some studies female zebra finches preferred males wearing red leg bands to orange-banded and unbanded birds and rejected light green-banded males. In other studies, females also preferred males with red beaks to orange-beaked males. However, several authors have failed to replicate these results. We show that females may fail to show a colour preference because of the absence or removal of ultraviolet light under experimental conditions. In mate-choice trials, females observing males through filters that transmitted ultraviolet preferred red-banded males but where females viewed males through ultraviolet-blocking filters, no such preference was observed. Further investigation revealed that the lack of a colour preference when ultraviolet was absent was probably due to the change in overall appearance of the bird, rather than the change in appearance of the rings themselves. This work highlights the importance of proper consider-ation of the sensory capabilities of animals in experimental design, particularly with regard to the role of ultraviolet light in avian colour perception.Copyright 1997 The Association for the Study of Animal BehaviourCopyright 1997The Association for the Study of Animal Behaviour.

Familial history of stroke and stroke risk. The Family Heart Study

BACKGROUND AND PURPOSE

Although familial history of stroke is generally perceived to be an important marker of stroke risk, very few epidemiological studies have been published to address this hypothesis. We sought to examine whether familial history of stroke is associated with the prevalence of stroke in the Family Heart Study, a National Heart, Lung, and Blood Institute-supported multicenter study of the familial, genetic, and nongenetic determinants of cardiovascular disease in populations.

METHODS

The personal and familial histories of stroke were assessed in 3168 individuals (probands) who were at least 45 years old and 29,325 of their first-degree relatives with the use of a standardized questionnaire.

RESULTS

The age-, ethnicity-, and sex-adjusted stroke prevalences were 4.8%, 4.9%, and 3.9% in probands with a positive familial, paternal, and maternal history of stroke, respectively, in comparison with 2.0% in probands without any positive familial history (P < .01). The age-, ethnicity-, and sex-adjusted odds ratios (95% confidence interval) of stroke were 2.00 (1.13, 3.54) for a positive paternal and 1.41 (0.80, 2.50) for a positive maternal history of stroke. Additional statistical adjustment for the proband's history of elevated cholesterol level, cigarette smoking status, history of coronary heart disease, hypertension, and diabetes did not alter the associations. A similar pattern was seen for African Americans and European Americans.

CONCLUSIONS

The increased risk of stroke among persons with a positive familial history of stroke compared with those without a familial history of stroke is consistent with the expression of genetic susceptibility, a shared environment, or both in the etiology of stroke.

Daily activity level buffers stress-glycemia associations in older sedentary NIDDM patients

Examined glycemic associations with medical variables, activity, daily stress, and mood state in 72 older patients with non-insulin-dependent diabetes mellitus (NIDDM). On three occasions over a 2-week observation period, subjects provided measures of everyday life stress, negative mood state, and daily activities. At the end of this period, fructosamine was assayed to measure glycemic control throughout the assessment period. After controlling for medical variables (age, illness duration, body mass index, caloric intake, and activity) and the main effects of psychological factors (stress; anxious, angry, and depressed mood states), stress interacted with activity such that glycemic elevation was positively associated with stress for subjects below the activity median but not for those above the median. This was unattributable to any overall activity-related differences in fructosamine, stress, or mood. None of the mood states interacted with activity. The findings suggest that extremely low levels of activity may strengthen life stress-glycemia associations in NIDDM.

The problem of quality of life in medicine

The use of the term "quality of life" to encompass the values and perceptions of patients has created doubt, confusion, and misunderstanding among practitioners, researchers, policymakers, and patients. The principal reason for this state of affairs is that a clear conceptual basis for quality-of-life measures is lacking. In this article, the current rationale for quality-of-life measurement in the health field is examined, and the drawbacks of the various models being used are outlined. Our suggestion is that quality of life as an outcome could be explored more clearly (ie, defined) if quality of life were replaced with a more easily handled notion such as that of "subjective health status." However, the idea that the patient's perspective is as valid as that of the clinician when it comes to evaluating outcomes has a great deal of legitimacy and should certainly not be abandoned.

The nucleotide sequence of Saccharomyces cerevisiae chromosome XIII

Systematic sequencing of the genome of Saccharomyces cerevisiae has revealed thousands of new predicted genes and allowed analysis of long-range features of chromosomal organization. Generally, genes and predicted genes seem to be distributed evenly throughout the genome, having no overall preference for DNA strand. Apart from the smaller chromosomes, which can have substantially lower gene density in their telomeric regions, there is a consistent average of one open reading frame (ORF) approximately every two kilobases. However, one of the most surprising findings for a eukaryote with approximately 6,000 genes was the amount of apparent redundancy in its genome. This redundancy occurs both between individual ORFs and over more extensive chromosome regions, which have been duplicated preserving gene order and orientation. Here we report the entire nucleotide sequence of chromosome XIII, the sixth-largest S. cerevisiae chromosome, and demonstrate that its features and organization are consistent with those observed for other S. cerevisiae chromosomes. Analysis revealed 459 ORFs, 284 have not been identified previously. Both intra- and interchromosomal duplications of regions of this chromosome have occurred.

The nucleotide sequence of Saccharomyces cerevisiae chromosome IX

Large-scale systematic sequencing has generally depended on the availability of an ordered library of large-insert bacterial or viral genomic clones for the organism under study. The generation of these large insert libraries, and the location of each clone on a genome map, is a laborious and time-consuming process. In an effort to overcome these problems, several groups have successfully demonstrated the viability of the whole-genome random 'shotgun' method in large-scale sequencing of both viruses and prokaryotes. Here we report the sequence of Saccharomyces cerevisiae chromosome IX, determined in part by a whole-chromosome 'shotgun', and describe the particular difficulties encountered in the random 'shotgun' sequencing of an entire eukaryotic chromosome. Analysis of this sequence shows that chromosome IX contains 221 open reading frames (ORFs), of which approximately 30% have been sequenced previously. This chromosome shows features typical of a small Saccharomyces cerevisiae chromosome.

The concept of outcome

The Enuresis Resource and Information Centre in the UK has recently launched a second edition of Guidelines on Minimum Standards of Practice in the Treatment of Enuresis. The purpose of the Guidelines is to provide a blueprint for service delivery in the UK, leading to enuresis services that offer effective, accessible and dependable treatment. In particular, these Guidelines propose minimum and target standards that enuresis services should aim to achieve, relating to referral, assessment and treatment, as well as catchment area appointments, research and referral. In addition, the Guidelines may be used to provide a framework within which enuresis services can be audited and evaluated. Successive cycles of observation, appraisal and action should encourage a continual improvement process in each clinic, resulting in a progressive development of the service offered.

Repeated administration of escalating high doses of dexfenfluramine does not produce morphological evidence for neurotoxicity in the cortex of rats

Rats were treated for 28 days with increasing doses of dexfenfluramine (0.5, 1, 1.5, 2, 3, 4 and 5 mg/kg bid ip, each dose given for 4 days before being increased) and subsequently studied at intervals between 1 and 60 days following the cessation of treatment. Control rats received vehicle and were allowed food ad libitum or were pair fed with dexfenfluramine-treated animals. Immediately following drug treatment 5-HT immunoreactivity was increased in cortical areas compared to control animals. Subsequently, there was a persistent decrease in fine fibre density and the appearance of coarse truncated fibres. 5-HT levels in cortex were decreased 1 day following dexfenfluramine treatment but recovered to control values by 15 days. GFAP and GAP 43 immunoreactivity was unaffected by dexfenfluramine treatment compared to control animals, indicating a lack of evidence for neuronal degeneration and regeneration. Dexfenfluramine treatment decreased the density of 5-HT uptake sites in the cortex, labelled with [3H]-citalopram, but this partially recovered towards control values at 60 days. These alterations in 5-HT terminal networks conflict with the return of 5-HT levels to normal and the lack of evidence for degenerative changes or neuronal regrowth. On the basis of these results, it cannot be concluded that dexfenfluramine is neurotoxic.

Organ culture of human main and accessory lacrimal glands and their secretory behaviour

The purpose of this study was to investigate the in vitro viability and secretory behaviour of human main and accessory lacrimal glands using an organ culture technique. We evaluated the influence of the second messengers cAMP and cGMP on secretion. Fragments less than 1 mm3 of main and accessory lacrimal glands as well as conjunctiva were cultured for 2-72 hr at 37 degrees C in an atmosphere consisting of 50% O2, 45% N2 and 5% CO2, using a specially devised culture medium (+/- cAMP or cGMP). The conjunctival tissue served as negative control. Supernatants were assayed for secretory-component-bound IgA, lactoferrin and lysozyme using ELISA. Cultured tissue pieces were embedded in paraffin, serially sectioned, stained and their volumes calculated using an image-analysis system. This enabled us to differentiate between secretory, connective and fatty tissue. Secreted exudate was correlated to the volume of secretory tissue. Viability of cultured organ pieces was determined by electron microscopic examination. Suitable organ culture conditions for human lacrimal glands were successfully established. Electron microscopic examinations proved that the structural characteristics of the organ and the polarity of the individual cells were well preserved up to 22 days of culture. Culture supernatants were assayed for secretory-component-bound IgA, lactoferrin, and lysozyme and showed that the amount of protein secreted increased with time. Upon addition of cAMP (1 x 10(-3) M) and cGMP (4 x 10(-3) M), secretion was elevated in both main and accessory lacrimal glands. An organ culture system for lacrimal glands was developed that maintains their structural and cellular characteristics as well as their secretory function for up to 22 days. We believe that this system mimics the in vitro state of the organ better than monolayer cultures and thus proves to be a valuable tool when examining lacrimal function in vitro. The fact that both cAMP and cGMP enhance secretion may help to shed some light on the cellular pathways human main and accessory lacrimal glands use for signal transduction.

Short contact 70% glycolic acid peels as a treatment for photodamaged skin. A pilot study

BACKGROUND

Glycolic acid has been one of the more commonly used alpha hydroxy acids for the treatment of photodamaged skin. Its value as a quick "skin refreshing" peeling agent has been widely touted. This type of peel differs from a conventional therapeutic peel (eg, phenol, trichloroacetic acid, or a longer time exposure alpha hydroxy acid peel) in that there is little skin reaction and patients can go about their daily routine without concern.

OBJECTIVE

To assess the potential value of glycolic acid-based refresher peels as a cosmetic procedure.

METHODS

Twelve healthy subjects with at least a moderate degree of photodamage were treated with monthly serial 70% glycolic acid peels over a period of 4 months. In addition to the "peels," six subjects were randomized to a 10% glycolic acid-based moisturizer twice daily. Patients were evaluated monthly and graded on a clinical scale using objective measures.

RESULTS

No conclusive differences were noted on histologic evaluation. Ninety percent (9/10) of patients felt that overall they noticed significant improvement, however, there was no distinction between the two treatment options. The improvement in fine wrinkling and pigmentation was primarily seen in the patients who additionally received 10% glycolic emollient twice daily.

CONCLUSION

In this limited pilot study, no specific benefit could be assigned to the concomitant use of monthly glycolic acid refresher "peels" in the treatment of photodamaged skin.

The 8.5-kb PstI allele of the stress protein gene, Hsp70-2: an independent risk factor for systemic lupus erythematosus in African Americans?

SLE is dramatically more prevalent in persons of African descent than in other populations. Several genes in the class III region of the MHC have been considered as potential susceptibility loci for this disorder, but the primary association(s) remains unknown. The stress protein gene, hsp70-2, is of special interest in this regard because it encodes a protein functionally relevant to antigen processing and presentation and has itself been identified as a putative susceptibility locus in organ-specific autoimmune diseases in Caucasians. To clarify the relationship of the hsp70-2 gene to SLE in African Americans, genomic DNA from 46 patients and 42 appropriately matched control subjects was analyzed for an RFLP of the hsp70-2 gene using the probe pH2.3 and the restriction endonuclease PstI, which identifies alleles of 8.5 and 9.0 kb. The 8.5-kb hsp70-2 allele was associated with SLE in this population (X2 = 8.2473, p = 0.0044). This association was not due to linkage disequilibrium with the C4A deletion or with HLA-DR3, as has been reported in Caucasians with IDDM. These data suggest that the 8.5-kb hsp70-2 allele may be an independent susceptibility marker for SLE in African Americans.

Risk adjustment: the missing piece of market competition

This DataWatch describes the process adopted by The Health Insurance Plan of California (The HIPC) for assessing and adjusting for health risk differences among participating health plans. We also report on the results of the 1996 risk assessment/adjustment calculations. A risk assessment value is calculated for each health plan based on the plan's enrollee mix as compared with the mix of enrollees in The HIPC as a whole. The results indicated that approximately 1 percent of total premium dollars needs to be transferred to bring all health plan scores within the acceptable level (+/- 5 percent) of risk distribution.

Influence of oxygen free radicals and free radical scavengers on the growth behaviour and oxidative tissue damage of bovine retinal pigment epithelium cells in vitro

PURPOSE

This investigation was carried out to ascertain whether oxygen free radicals can influence the growth behaviour and consecutive lipid peroxidation of retinal pigment epithelium (RPE) cells in vitro and whether scavengers can counteract these effects.

METHODS

The experimental model was based on calf RPE cells. Hypoxanthine/xanthine oxidase (HX/XO) and superoxide dismutase/ catalase (SOD/CAT) served as the radical generating system and scavengers, respectively. The components were tested alone and in combination. Lipid peroxides were determined in culture supernatants by a thiobarbituric acid assay.

RESULTS

Concentrations of up to 100 mumol/l of HX alone and 500/ 1000 microU of XO alone, as well as the application of the scavengers without the radical generating system (HX/XO), had no effect. Dose-related reduction of cell growth and increase of lipid peroxidation were found with HX/XO treatment (single dose of 500 and 1000 microU/ml 24 h after seeding). After application of 500 or 1000 microU/ml of XO, CAT, when given alone (1200 U/ ml), counteracted the effect of the radicals on cell growth and lipid peroxidation; SOD (300 U/ml) had no effect. A combination of SOD and CAT was no better than the effect of CAT alone.

CONCLUSION

The prevention of radical-induced reduction of cell growth and lipid peroxidation by scavengers supports trials of therapy using antioxidants and/or free radical scavengers for various ocular syndromes with RPE involvement.

Prophylactic ganciclovir treatment reduces fungal as well as cytomegalovirus infections after heart transplantation

Cytomegalovirus (CMV) infection is associated with an increased incidence of other opportunistic infections in organ transplant recipients. Whether this is related to immunomodulating effects of CMV or independent of CMV but associated with a host risk factor common to both infections is unclear. The purpose of this study was to determine whether the reduction in CMV infections seen with prophylactic ganciclovir treatment after heart transplantation is associated with a reduced incidence of other opportunistic infections. Of 149 patients prospectively enrolled in a multicenter, randomized, double-blind, placebo-controlled trial of ganciclovir to prevent CMV disease, 74 patients enrolled at this center (33 control and 41 ganciclovir-treated) were retrospectively identified. All received prophylactic OKT-3 and standard 3 drug maintenance immunosuppressive therapy. Actuarial survival and rejection rates and incidence of opportunistic infections (bacterial, fungal, and protozoal) for the 2 treatment groups were determined and compared using Cox-Mantel analysis. CMV disease occurred 2.5 times more frequently in the control group. There were no significant differences in survival or rejection rates nor in bacterial or protozoal infection incidence between the 2 groups. Bacterial infections occurred in 54% of control and 39% of ganciclovir-treated patients (P = 0.18). There were significantly fewer fungal infections in the ganciclovir-treated group (7% vs. 27%, P = 0.0071). CMV and fungal infections were both significantly reduced in patients who received ganciclovir prophylaxis. This suggests that active CMV disease may be causally associated with the development of opportunistic fungal infections.

Characteristics of patients surviving more than ten years after cardiac transplantation

The clinical status and quality of life of 40 patients who lived or are still alive more than 10 years after transplantation at our institution were reviewed with the use of our transplant database, prospective patient examinations, cardiac catheterization, and exercise testing. Patient-perceived health status was determined with use of the Nottingham Health Profile and General Well Being examinations. Factors associated with longevity were determined by a Cox proportional hazards model. Twenty-six patients are alive and 14 have died. The mean age at transplant was 32.4 +/- 12 years and the current age (or age at death) is 46.1 +/- 12.8 years. Actuarial freedom from rejection was similar to that of patients surviving less than 10 years (p = 0.8), but freedom from all types of infection was less (p = 0.005). Immunosuppressive drugs include cyclosporine (11/26 patients), azathioprine (24/26), and prednisone (26/26, mean dose 12.7 mg/day). Catheterization hemodynamic data show well-preserved graft function at a mean follow-up of 11.7 +/- 3.3 years. Graft coronary artery disease prevalence is 51.0% +/- 8%. Exercise test results are as follows: duration 8.7 +/- 3.5 minutes (range 2 to 16 minutes), maximum heart rate/expected rate 77.3% +/- 11% (50% to 92%), maximum systolic blood pressure 171 +/- 23 mm Hg (140 to 208 mm Hg), and metabolic equivalents 9.2 +/- 2.3 units (5.5 to 12.9 units), or about 84% of predicted. Mean score on the General Well Being examination was 75.3 +/- 21.6 (normal). Nottingham Health Profile scores were nearly normal, except for in the 50- to 64-year-old age group in categories of mobility, pain, sleep quality, and energy level. Causes of death were coronary artery disease in 7 of 14, infection in 4 of 14, lymphoma in 1 of 14, and nonlymphoid cancer in 2 of 14. In the Cox regression, variables most associated with survival (t > 2.0, multivariate p = 0.0005) were age at transplantation (t = 3.26), preoperative duration of illness (t = 3.57), postoperative cytomegalovirus infection (t = 2.16), and ejection fraction at 12 months after operation (t = -2.62). We conclude that cardiac transplantation can provide patients with end-stage cardiac failure an acceptable general medical condition, functional status, and perceived quality of life well into the second decade after operation.

Morphological and molecular response of the MOCH-1 oligodendrocyte cell line to serum and interferon-gamma: possible implications for demyelinating disorders

The regional loss of oligodendrocytes is thought to be an important pathological event in a variety of demyelinating diseases of the central nervous system (CNS). Various components of serum, which are normally excluded from the CNS by the blood-brain barrier, have been implicated as mediators of demyelinating disorders. We have examined the effects of high concentrations of serum (10% fetal bovine serum, FBS), as well as the cytokine interferon-gamma (IFN-gamma), on an oligodendrocyte cell line, MOCH-1 cells. These cells changed from phase-bright, small round cells with multiple thin, branched processes in 1% FBS medium to flat, fibroblast-like cells with large cell bodies when cultured in 10% FBS medium or 1% FBS medium containing IFN-gamma. These morphological changes were accompanied by a large increase in expression of the astrocyte marker, glial fibrillary acidic protein (GFAP), as detected by Northern and Western blot analyses. In addition, Northern blot and fluorescence-activated cell sorting analyses revealed that IFN-gamma induced a very large increase in major histocompatibility complex (MHC) class I expression in MOCH-1 cells. MHC class II mRNA induction by IFN-gamma was also seen. In contrast, 10% FBS did not elevate either MHC class I or class II mRNA levels in MOCH-1 cells. The morphological and molecular effects of 10% FBS and IFN-gamma were reversible. We suggest that the response of MOCH-1 cells to high concentrations of serum and IFN-gamma may reflect an important in vivo response to oligodendrocytes to perturbations that occur in demyelinating disorders.

The Role of Oxygen in the Regulation of Nitrogenase Activity in Drought-Stressed Soybean Nodules

The aim of this study was to investigate the mechanism of nitrogenase inhibition in drought-stressed soybean (Glycine max L.) nodules to determine whether this stress was similar to other inhibitory treatments (e.g. detopping) known to cause an O2 limitation of nodule metabolism. Nodulated soybean plants were either detopped or subjected to mild, moderate, or severe drought stress by growth in different media and by withholding water for different periods. All treatments caused a decline in nitrogenase activity, and in the drought-stressed nodules, the decline was correlated with more negative nodule water potentials. Increases in rhizosphere O2 concentration stimulated nitrogenase activity much more in detopped plants than in drought-stressed plants, reflecting a greater degree of O2 limitation with the detopped treatment than with the drought-stressed treatment. These results indicated that drought stress differs from many other inhibitory treatments, such as detopping, in that its primary cause is not a decrease in nodule permeability and a greater O2 limitation of nodule metabolism. Rather, drought stress seems to cause a decrease in the maximum O2-sufficient rate of nodule respiration or nitrogenase activity, and the changes in nodule permeability reported to occur in drought-stressed nodules may be a response to elevated O2 concentrations in the infected cell that may occur as nodule respiration declines.

Information needs of health care professionals in an AIDS outpatient clinic as determined by chart review

OBJECTIVE

To examine the information needs of health care professionals in HIV-related clinical encounters, and to determine the suitability of existing information sources to address those needs.

SETTING

HIV outpatient clinic.

PARTICIPANTS

Seven health care professionals with diverse training and patient care involvement.

METHODS

Based on patient charts describing 120 patient encounters, participants generated 266 clinical questions. Printed and on-line information sources were used to answer questions in two phases: using commonly available sources and using all available medical library sources.

MEASUREMENTS

The questions were divided into 16 categories by subject. The number of questions answered, their categories, the information source(s) providing answers, and the time required to answer questions were recorded for each phase.

RESULTS

Each participant generated an average of 3.8 clinical questions per chart. Five categories accounted for almost 75% of all questions; the treatment protocols/regimens category was most frequent (24%). A total of 245 questions (92%) were answered, requiring an average of 15 minutes per question. Most (87%) of the questions were answered via electronic sources, even though paper sources were consulted first.

CONCLUSIONS

The participating professionals showed considerable information needs. A combination of on-line and paper sources was necessary to provide the answers. The study suggests that present-day information sources are not entirely satisfactory for answering clinical questions generated by examining charts of HIV-infected patients.

Behavioral Intensive Care Unit (BICU): a new concept in the management of acute agitated behavior in elderly demented patients

Intensive care units were developed in response to the perceived need for increased monitoring in critically ill medical patients. The same principle applies to elderly patients with severe agitated behaviors. These patients can be served by the Geriatric Behavioral Intensive Care Unit (BICU). The uniqueness of the program results from the application of a behavioral and environmental approach to the treatment of agitated behavior. The underlying strategy in the treatment process is to enhance the patient's ability to adapt to his or her home environment. Preliminary results have been encouraging, showing positive outcomes in diverse areas such as low level of institutional placement, patient quality of life, and caregiver symptoms of burden and depression.

Role of Oxygen in the Limitation and Inhibition of Nitrogenase Activity and Respiration Rate in Individual Soybean Nodules

Although infected cell O2 concentration (Oi) is known to limit respiration and nitrogenase activity in legume nodules, techniques have not been available to measure both processes simultaneously in an individual legume nodule. Consequently, details of the relationship between nitrogenase activity and Oi are not fully appreciated. For the present study, a probe was designed that allowed open circuit measurements of H2 evolution (nitrogenase activity) and CO2 evolution (respiration rate) in a single attached soybean nodule while simultaneously monitoring fractional oxygenation of leghemoglobin (and thereby Oi) with a nodule oximeter. Compared to measurements of whole nodulated roots, use of the probe led to inhibition of nitrogenase activity in the single nodules. During oximetry measurements, total nitrogenase activity (TNA; peak H2 evolution in Ar/O2) in the single nodules was 16% of that in whole nodulated roots and 48% of nodulated root activity when Oi was not being measured simultaneously. This inhibition did not affect the nodules' ability to regulate Oi, because exposure to Ar/O2 (80:20, v/v) caused nitrogenase activity and respiration rate to decline, and this decline was linearly correlated with a concurrent decrease in Oi. When the nodules were subsequently exposed to a linear increase in external pO2 from 20 to 100% O2 at 2.7% O2/min, fractional leghemoglobin oxygenation first increased gradually and then more rapidly, reaching saturation at a pO2 between 76 and 100% O2. Plots of nitrogenase activity and respiration rate against Oi showed that rates increased with Oi up to a value of 57 nM, with half-maximal rates being attained at Oi values between 10 and 14 nM O2. The maximum nitrogenase activity achieved during the increase in pO2 (potential nitrogenase activity) was 30 to 57% of that measured in intact nodulated roots, showing that O2 limitation of nitrogenase activity could account for a significant proportion of the inhibition of TNA associated with the use of the probe. However, some factor(s) in addition to O2 must have limited the activity of single nodules at both subsaturating and saturating Oi. At Oi values greater than about 57 nM, nitrogenase activity and nodule respiration were inhibited, but, because this inhibition has been shown previously to be readily reversible when the Oi was lowered, it was not attributed to direct O2 inactivation of the nitrogenase protein. These results indicate that maximum nitrogenase activity in legume nodules is supported by a narrow range of Oi values. Possible biochemical mechanisms are discussed for both O2 limitation of nitrogenase activity at low Oi and inhibition of nitrogenase activity at high Oi.

Spinal nerve enhancement with Gd-DTPA: MR correlation with the postoperative lumbosacral spine

PURPOSE

To search for a probable source of the recurrent signs and symptoms associated with lumbosacral postsurgical syndrome on intravenous gadolinium-enhanced MR.

METHODS

A retrospective study of 120 patients with recurrent symptomatology following lumbar disk surgery was carried out with spin-echo MR pre- and postenhancement with gadopentetate dimeglumine (0.1 mmol/kg). In addition, 10 asymptomatic subjects were evaluated at least 6 months postoperatively using the same imaging protocol.

RESULTS

21.6% of the symptomatic subjects (N = 26) had enhancement of one or more spinal nerve root. This enhancement was focal or multisegmental, and involved single or multiple nerve roots. The abnormal neural enhancement was associated with otherwise isolated epidural fibrosis in 88.5%, and with herniated nucleus pulposus in the remaining 11.5%. The overall clinical correlation of single root enhancement with a monoradiculopathy and multiroot enhancement with a polyradiculopathy was 95.7%. However, 21.7% of these same cases also showed additional nerve root enhancement that did not have an overt clinical correlation. All of these latter patients were imaged relatively early in the postoperative period (5 days to 8 months). The 10 patients in the asymptomatic group all manifested degrees of postoperative epidural scarring on MR, but no abnormal radicular enhancement or other associated pathology.

CONCLUSION

In the chronic postoperative phase (more than 6 to 8 months), the presence of radicular enhancement on MR imaging in symptomatic individuals, and its absence in asymptomatic subjects, suggests that neural enhancement serves as a marker for active neural pathology that may in certain individuals be related temporally to the signs and symptoms associated with the lumbosacral postsurgical syndrome.

Predictors of survival after repeat heart transplantation. The Registry of the International Society for Heart and Lung Transplantation, and Contributing Investigators

To examine factors potentially predictive of outcome after repeat heart transplantation, data were analyzed for 449 recipients of second allografts reported to the registry of the International Society for Heart and Lung Transplantation and a matched group of 421 primary transplant recipients. Survival was markedly decreased in repeat transplantation patients (1 year actuarial survival rate, 48% vs 79%; p less than 0.001). Univariate analysis showed no impact on survival of recipient age or gender, ischemic time, or transplant center experience. Accelerated coronary artery disease as the cause of allograft failure, longer interval between transplants, lack of preoperative mechanical assistance, and second transplantation after 1985 were predictive of increased survival after repeat transplantation. An "ideal candidate" defined by these predictive variables had a 1-year survival rate of 64%. In addition to the International Society for Heart and Lung Transplantation registry, a multicenter data base was developed with data for 125 repeat transplant recipients and 1325 primary transplant recipients at 13 transplant centers in the United States. In this group of patients the 1-year survival rate was greater than that in the International Society for Heart and Lung Transplantation registry (60% vs 48%), and the impact of the predictive variables listed previously was decreased. The incidence of rejection, infection, and accelerated coronary artery disease was not different between secondary and primary allograft recipients. Nonskin malignancies occurred more frequently in repeat transplantation patients (8% vs 4%; p less than 0.05). Recipients of second allografts were more likely to have major surgical complications, had a higher level of sensitization to HLA antigens, and were more likely to have a positive donor-specific crossmatch (17% vs 2%). A trend toward improved survival was noted in patients with repetition in the second donor of mismatched HLA antigens present in the first donor (1-year survival rate of 68% vs 47%; p = 0.06). We conclude that longer interval between transplants, accelerated coronary artery disease as cause of allograft loss, and lack of preoperative mechanical assistance are predictive of longer survival after repeat transplantation. Nonetheless, the "ideal candidate" for repeat transplantation has an anticipated survival rate significantly less than that expected for primary transplant recipients.

Nitrogenase activity, nodule respiration, and o(2) permeability following detopping of alfalfa and birdsfoot trefoil

Gas exchange measurements and noninvasive leghemoglobin (Lb) spectrophotometry (nodule oximetry) were used to monitor nodule responses to shoot removal in alfalfa (Medicago sativa L. cv Weevlchek) and birdsfoot trefoil (Lotus corniculatus L. cv Fergus). In each species, total nitrogenase activity, measured as H(2) evolution in Ar:O(2) (80:20), decreased to <50% of the initial rate within 1 hour after detopping, and net CO(2) production decreased to about 65% of the initial value. In a separate experiment in which nodule oximetry was used, nodule O(2) permeability decreased 50% within 5 hours in each species. A similar decrease in the O(2)-saturated respiration rate (V(max)) for the nodule central zone occurred within 5 hours in birdsfoot trefoil, but only after 24 hours in alfalfa. Lb concentration, also measured by oximetry, decreased after 48 to 72 hours. The decrease in permeability preceded the decrease in V(max) in each species. V(max) may depend mainly on carbohydrate availability in the nodule. If so, then the decrease in permeability could not have been triggered by decreasing carbohydrate availability. Both oximetry and gas exchange data were consistent with the hypothesis that, for the cultivars tested, carbohydrate availability decreased more rapidly in birdsfoot trefoil than in alfalfa nodules. Fractional Lb oxygenation (initially about 0.15) decreased during the first 24 hours after detopping but subsequently increased to >0.65 for a majority of nodules of each species. This increase could lead to O(2) inactivation of nitrogenase.

Cost containment: coadministration of diltiazem with cyclosporine after heart transplantation

Coadministration of diltiazem with cyclosporine (CsA) has been reported to alter the metabolism of CsA, resulting in increased blood concentration with potential nephrotoxicity if dosage is not adjusted. This report analyzes the cost saving resulting from use of diltiazem and CsA together and examines the impact on renal function. Sixty-nine heart transplant recipients (59 men, 10 women) were randomized to diltiazem (n = 32) or to no calcium blocker (n = 37). Age range was 18 to 58 years. All patients received CsA (titrated to a 12-hour trough serum level of 100 to 200 ng/ml), azathioprine, and prednisone. Diltiazem was begun at 30 mg three times daily increasing to 60 mg three times daily at 1 month, as tolerated. Renal function was assessed by serial measurements of serum creatinine. Parameters before and after starting diltiazem were compared by paired t-tests, and differences between group means by analysis of variance. CsA doses and levels were comparable at baseline in both groups. At 12 months, CsA dose requirement was 2.5 +/- 1.0 versus 5.9 +/- 3.2 mg/kg/day (diltiazem group versus no calcium blocker group; p less than or equal to 0.001) to achieve similar serum levels (96 +/- 51 versus 123 +/- 96 ng/ml; p = NS). This represents a 48% reduction in dose cost of CsA. The average cost of CsA for 2 to 4 months of therapy in a patient weighing 70 kg was reduced from $12,122 in the no calcium blocker group to $6,356 in the diltiazem group.(ABSTRACT TRUNCATED AT 250 WORDS)

Recurring patterns of inflammatory sinonasal disease demonstrated on screening sinus CT

PURPOSE

In order to define specific features on screening sinus CT (SSCT) that will aid the endoscopic surgeon in his approach to patients with inflammatory sinonasal disease, we sought to answer four questions: 1) what recurring patterns of inflammatory sinonasal disease are evident on SSCT; 2) what is the relative frequency of these recurring patterns; 3) how do these CT patterns correlate with the known sinus mucociliary drainage routes; and 4) what are the characteristic radiologic features of each pattern?

METHODS

We reviewed the clinical and radiologic records of 500 consecutive patients who underwent SSCT as a prelude to possible functional endoscopic sinus surgery.

RESULTS

Five recurring radiologic patterns of sinonasal inflammatory disease were identified: 1) infundibular (129/500 or 26%), 2) ostiomeatal unit (126/500 or 25%) 3) sphenoethmoidal recess (32/500 or 6%), 4) sinonasal polyposis (49/500 or 10%), and 5) sporadic (unclassifiable) (121/500 or 24%) patterns. Normal SSCT was seen in 133/500 patients (27%).

CONCLUSION

Identification of specific patterns of sinonasal disease permits grouping of patients into nonsurgical (normal CT), routine (infundibular, ostiomeatal unit, and most sporadic patterns) and complex (sinonasal polyposis and sphenoethmoidal recess patterns) surgical groups. Assignment of patients to radiologic patterns allows a tailored surgical approach.

A comparison of the consistency of self-reported behavioural change within a study sample--postal versus home interviews

Much health promotion research is directed towards increasing our understanding of the process of health-related behavioural change. However, little is known about the validity of self-reported changes in behaviour. This study aimed to assess the validity of self-reported changes in five behaviours--diet, cigarette smoking, alcohol consumption, weight control and physical activity--by comparing reports obtained from the same people through postal questionnaires and face-to-face interviews. It was found that overall there was a consistency between self-reports with interviewers confirming that in most cases change had taken place. However, in a large number of cases changes were reported that had occurred before the period specified in the questionnaire. The nature of the change, whether discrete or incremental, as well as the behaviour in question, were found to be related to the accuracy of self-reporting. The possible reasons for the observed discrepancies are discussed.

The impact of screening sinus CT on the planning of functional endoscopic sinus surgery

The clinical and radiologic records of 500 sequential patients who underwent screening sinus CT as a prelude to possible functional endoscopic sinus surgery (FESS) were reviewed in order to answer three clinical-radiologic questions: (1) Can distinct radiologic patterns of inflammatory disease be identified on screening sinus CT (SSCT)? (2) If so, what are these radiologic patterns? (3) How do the findings seen on SSCT influence the endoscopic surgical plan? Five basic radiologic patterns of sinonasal inflammatory disease were identified among the 500-member patient population. These were based on known patterns of mucociliary drainage correlated with obstructive patterns observed on the CT scans. These radiologic patterns included: (1) infundibular (129 of 500 or 26%), (2) ostiomeatal unit (126 of 500 or 25%), (3) sphenoethmoidal recess (32 of 500 or 6%), (4) sinonasal polyposis (49 of 500 or 10%), and (5) sporadia (unclassifiable) (121 of 500 or 24%) patterns. Normal SSCT was seen in 133 of the 500 patients (27%). Although the ostiomeatal unit is the central feature in sinonasal inflammatory disease, obstruction of the infundibulum alone or of the sphenoethmoidal recess can cause unique inflammatory patterns of disease that require tailored FESS. The identification of sinonasal polyposis raises a different set of FESS considerations. The sporadic pattern of inflammatory disease, when identified, creates unique FESS challenges, depending on the specific sinus or sinuses involved. Assignment of these patterns to the individual case also assists in patient management by grouping patients into nonsurgical (normal CT), routine (infundibular, ostiomeatal unit, and most sporadic patterns) and complex (sinonasal polyposis and sphenoethmoidal recess) surgical groups.