The use of covariance functions and random regressions for genetic evaluation of milk production based on test day records

In the analysis of test day records for dairy cattle, covariance functions allow a continuous change of variances and covariances of test day yields on different lactation days. The equivalence between covariance functions as an infinite dimensional extension of multivariate models and random regression models is shown in this paper. A canonical transformation procedure is proposed for random regression models in large-scale genetic evaluations. Two methods were used to estimate covariance function coefficients for first parity test day yields of Holsteins: 1) a two-step procedure fitting covariance functions to matrices with estimated genetic and residual covariances between predetermined periods of lactation and 2) REML directly from data with a random regression model. The first method gave more reliable estimates, particularly for the periphery of the trajectory. The goodness of fit of a random regression model based on covariables describing the shape of the lactation curve was nearly the same as random regression on Legendre polynomials. In the latter model, two and three regression coefficients were sufficient to fit the covariance structure for additive genetic and permanent environment, respectively. The eigenfunction pattern revealed the possibility of selection for persistency. Covariance functions can be usefully implemented in large-scale test day models by means of random regressions.

Sorting human beta-cells consequent to targeted expression of green fluorescent protein

Pancreatic islets of Langerhans are composed of four major endocrine cell types with a smaller number of nonendocrine cells. To study the molecular constituents and function of just one subpopulation of islet cells, it is necessary to sort them from the other cell types. While rat beta-cells can be sorted by autofluorescence-activated flow cytometry, this has not proved possible on a routine and reproducible basis for human beta-cells. In the present study, we have selectively labeled human beta-cells with green fluorescent protein (GFP), allowing for their sorting by flow cytometry. Human islet cells were infected with replication-defective (attenuated) recombinant adenovirus expressing GFP driven by the rat insulin I promoter (Ad-RIP-GFP) for targeted expression in beta-cells, or beta-galactosidase driven by the promiscuous cytomegalovirus (CMV) promoter (Ad-CMV-beta-gal) as control. Whereas the majority of islet cells can be infected by adenovirus, as shown by control infection with Ad-CMV-beta-gal, increased fluorescence after infection with Ad-RIP-GFP was limited to insulin-containing beta-cells. Infection of islet cells with Ad-RIP-GFP resulted reproducibly in the appearance of a population of intensely fluorescent cells, when analyzed by flow cytometry. These cells were sorted using a fluorescence-activated cell sorter (FACS) and shown by immunofluorescence to consist of >95% beta-cells. The targeted expression of GFP thus allows for preparation of human beta-cells purified close to homogeneity. This method should be readily applicable in any laboratory with FACS capability.

Comparison of left ventricular function during interval versus steady-state exercise training in patients with chronic congestive heart failure

This study sought to assess the safety of interval exercise training in patients with chronic congestive heart failure (CHF) with respect to left ventricular (LV) function. For effective rehabilitation in CHF, both aerobic capacity and muscle strength need to be improved. We have previously demonstrated in both coronary artery bypass surgery and patients with CHF that interval exercise training (IET) offers advantages over steady-state exercise training (SSET). However, because LV function during IET has not yet been studied, the safety of this method in CHF remains unclear. To assess LV function during IET and SSET, at the same average power output, 11 patients with stable CHF were compared with 9 stable coronary patients with minimal LV dysfunction (control group). Using first-pass radionuclide ventriculography, changes in LV function were assessed during work versus recovery phases, at temporally matched times between the fifth and sixteenth minute of IET and SSET. In CHF during IET, there were no significant variations in the parameters measured during work and/or recovery phases. During the course of both IET and SSET, there was a significant increase in LV ejection fraction (5 vs 4 U; p <0.05 each), accompanied by increased heart rate (6 vs 8 beats/min; p <0.05 each) and cardiac output (2.4 vs 1.8 L/min; p <0.01 and p <0.05). In CHF, the magnitude of change in LV ejection fraction during IET was similar to that seen in controls. Both LV ejection fraction and the clinical status in patients with CHF remained stable during IET. Because IET appears to be as safe as SSET with respect to LV function, IET can be recommended for exercise training in CHF to apply higher peripheral exercise stimuli and with no greater LV stress than during SSET.

Flow cytometric identification of myeloid disorders by asynchronous expression of the CD14 and CD66 antigens

Using a multiparameter flow cytometry assay enumerating cells positive for CD13, CD14 and CD66 antigens, we determined the asynchronous CD14/CD66 co-expression in unselected bone marrow and peripheral blood samples with suspected malignant blood disorders. CD14/CD66 co-expression > or = 5% were found in 131/691 bone marrow samples. Only 55 of these exhibited an identifiable population in 2-parameter flow cytometry histograms. Of the 55 samples 43 (78%) came from patients with myeloid disorders; e.g. 11 with myelodysplastic syndromes, 15 with chronic myeloproliferative disorders and 17 with acute myeloid leukaemia. Only one of these 17 cases was a de novo case, while 8 were secondary to another malignant haematological disease and 8 were from the period after cytoreductive therapy. Notably, CD14/CD66 co-expression patterns were related to disease categories; e.g. in chronic myelomonocytic leukaemia and acute myeloid leukaemia following a dysplastic phase the co-expression displayed two subsets in peripheral blood, low-avidity CD14 and low-avidity CD66, respectively. The latter disease category also exhibited these 2 subsets in bone marrow. In all other cases, the CD14/CD66 co-expression in bone marrow was heterogeneous. In conclusion, abnormal CD14/CD66 co-expression might be a valuable parameter in defining asynchronous myelopoiesis in malignant myeloid disorders, especially myeloproliferative disorders and secondary acute myeloid leukemias.

Practical aspects of managing preschool children with type 1 diabetes

Day-to-day variations in diet and physical exercise, large variations in the glucose response to small changes in insulin doses, and high insulin sensitivity are characteristic of preschool children with diabetes. Hence, difficulties in achieving adequate metabolic control and stable glycaemia in preschool children are common. In addition, hypoglycaemic episodes tend to be frequent and severe in this age group. Problems identifying and treating hypoglycaemia present an additional challenge for the diabetes team and for the family caring for the young child with diabetes. Specific glucose targets are provided for this age group: premeal levels of 6-12 mmoll(-1)(110-220 mg dl(-1)) with bedtime levels above 8 mmoll(-1)(140 mg dl(-1)). It is important to note that children who suffer severe hypoglycaemic events at a young age show evidence of subtle cognitive deficits when tested during adolescence. The question of whether or not the years before pubertal onset contribute less towards the development of diabetes-related microvascular complications than do the years starting with the onset of puberty remains controversial. Twice-daily or multiple insulin injections, dietary adjustments and considerations, home blood-glucose monitoring, family education, support groups and 24-h hotline information facilities can help to achieve good metabolic control without severe hypoglycaemia in the preschool child. In general, good metabolic control without severe hypoglycaemia can be achieved using frequent counselling and a caring team approach.

Physiological and pathological aspects of exercise left ventricular function

Measures of left ventricular function during exercise provide information that is more accurate than the exercise ECG in the diagnosis of coronary artery disease, supportive of the data provided by myocardial perfusion studies, and of great prognostic significance. We review basic methods for evaluating left ventricular function during exercise and responses to various types of exercise, including incremental exercise and exercise training conditions. Additionally, we review changes in both incremental exercise test responses and responses to training in various pathological conditions. Case reports are included to illustrate the utility of measuring left ventricular function during exercise.

Total knee and hip arthroplasty in haemophilic patients

We evaluated the long-term results of three total hip and nine total knee arthroplasties in nine haemophilic patients with disabling pain and end-stage arthropathy. These patients have been followed over a period of 2-12 years (mean 6.9). One patient had a post-operative haematoma, which was evacuated; two patients required manipulation of the knee because of a limited range of motion. There were no infections. At follow-up, all but two patients were completely free of pain; two patients had occasional pain. The functional improvement was impressive with an average increase in the knee score from 37 to 80 points post-operatively. The hip score increased from 36 to 85 points. The range of motion was increased in seven joints, unchanged in two joints and decreased in three. One total hip arthroplasty was revised after 9 years for aseptic loosening. One total knee demonstrated nonprogressive radiographic evidence of aseptic loosening. Median consumption of coagulation factor concentrate in severe haemophiliacs decreased from 47.00 U yr-1 (range 16.000-144.000) before surgery, to 25.000 U yr-1 (range 18.000-132.000) at 2 years after surgery.

CONCLUSION

Hip and knee arthroplasty is a valuable option in symptomatic haemophilic patients with disabling arthropathy, in order to obtain pain relief and functional improvement. It is associated with a low rate of complications and may reduce the need for substitution of factor VIII and IX.

The Early vs Late Infantile Strabismus Surgery Study: do sources for bias exist in this non-randomised trial? Early vs Late Infantile Strabismus Surgery Study Group

BACKGROUND

The Early vs Late Infantile Strabismus Surgery Study Group investigates whether early or late surgery is preferable in infantile convergent strabismus, in a non-randomised, prospective, multicentre clinical trial. The current state of the study after end of recruitment is reported here, focusing on the question of possible sources for bias in this non-randomised trial.

METHOD

The prognostic factors were analysed at baseline in order to check for imbalances between the two treatment groups. Reasons for possible differences are discussed.

RESULTS

There is no evidence for clinically relevant inhomogeneities between the two groups concerning the distribution of the three prognostic factors spherical equivalent, degree of amblyopia, and limitation of abduction. The fourth prognostic factor, horizontal angle of squint, differs significantly between the two groups.

CONCLUSION

In the analysis of the final results we may have to account for differences in angle of squint at baseline by its inclusion as a covariate or by stratification.

Leptin as a metabolic regulator during fetal and neonatal life and in childhood and adolescence

Body weight is regulated by a feedback loop in which peripheral signals report nutritional information to an integratory center in the brain. The cloning of the ob gene is consistent with this concept and suggests that body fat content in adult rodents is regulated by a negative feedback loop centered in the hypothalamus/1-8/. In a recent report, two severely obese children with congenital leptin deficiency due to a homozygous frame-shift mutation involving the deletion of a single guanine nucleotide in codon 133 of the ob gene have been described. This discovery provides the first genetic evidence that leptin is an important regulator of energy balance in humans. However, it has become increasingly clear that apart from leptin's function in the central nervous system and in regulation of energy balance, leptin also acts in the periphery and might be important as a hormone modulating processes in regard to reproduction, glucose metabolism and insulin resistance, as well as growth and development of many tissues and organs either directly or indirectly. This report reviews some of the topics of leptin research that are of particular importance and relevance for pediatric and adolescent medicine and for pediatric endocrinology in particular.

Lignin monomer composition is determined by the expression of a cytochrome P450-dependent monooxygenase in Arabidopsis

The phenylpropanoid pathway provides precursors for the biosynthesis of soluble secondary metabolites and lignin in plants. Ferulate-5-hydroxylase (F5H) catalyzes an irreversible hydroxylation step in this pathway that diverts ferulic acid away from guaiacyl lignin biosynthesis and toward sinapic acid and syringyl lignin. This fact led us to postulate that F5H was a potential regulatory step in the determination of lignin monomer composition. To test this hypothesis, we have used Arabidopsis to examine the impact of F5H overexpression. Arabidopsis is a useful model system in which to study lignification because in wild-type plants, guaiacyl and syringyl lignins are deposited in a tissue-specific fashion, while the F5H-deficient fah1 mutant accumulates only guaiacyl lignin. Here we show that ectopic overexpression of F5H in Arabidopsis abolishes tissue-specific lignin monomer accumulation. Surprisingly, overexpression of F5H under the control of the lignification-associated cinnamate-4-hydroxylase promoter, but not the commonly employed cauliflower mosaic virus 35S promoter, generates a lignin that is almost entirely comprised of syringylpropane units. These experiments demonstrate that modification of F5H expression may enable engineering of lignin monomer composition in agronomically important plant species.

Performance of the SE-9000 automated haematology analyser in a laboratory serving a haematological oncology unit

The performance of the SE-9000 automated haematology analyser in a laboratory receiving a high number of abnormal specimens from haematological oncology patients was assessed according to formal protocols for the evaluation of blood cell counters. Linearity over a useful working range, precision in clinically important ranges and negligible carry-over were demonstrated in this group of patient samples confirming the results of previous investigators. The comparability of instrument derived differential leucocyte counts from both normal and distributionally abnormal samples with those obtained by visual microscopy using the NCCLS H-20 A protocol was very good. The sensitivity of flags for the detection of immature granulocytes and myeloid blast cells was high and this can be attributed to the incorporation of a new measuring channel (Immature Myeloid Information or IMI channel). The number of unrecognized abnormalities was low and when compared with the poor sensitivity of the routine 100-cell visual differential leucocyte count, the analyser was judged suitable for monitoring patients with haematological malignancies. The performance of flags such as 'left shift' and 'atypical lymphocytes' can be improved by taking into consideration distributional abnormalities such as neutrophilia and lymphocytosis. The trigger level for these flags should be adapted to the clinical need particularly in cases of neutropenia following chemotherapy, and in lymphoproliferative disorders and infection.

Functional role of hepatitis C virus chimeric glycoproteins in the infectivity of pseudotyped virus

The putative envelope glycoproteins of hepatitis C virus (HCV) likely play an important role in the initiation of viral infection. Available information suggests that the genomic regions encoding the putative envelope glycoproteins, when expressed as recombinant proteins in mammalian cells, largely accumulate in the endoplasmic reticulum. In this study, genomic regions which include the putative ectodomain of the E1 (amino acids 174 to 359) and E2 (amino acids 371 to 742) glycoproteins were appended to the transmembrane domain and cytoplasmic tail of vesicular stomatitis virus (VSV) G protein. This provided a membrane anchor signal and the VSV incorporation signal at the carboxy termini of the E1 and E2 glycoproteins. The chimeric gene constructs exhibited expression of the recombinant proteins on the cell surface in a transient expression assay. When infected with a temperature-sensitive VSV mutant (ts045) and grown at the nonpermissive temperature (40.5 degrees C), cells transiently expressing the E1 or E2 chimeric glycoprotein generated VSV/HCV pseudotyped virus. The resulting pseudotyped virus generated from E1 or E2 surprisingly exhibited the ability to infect mammalian cells and sera derived from chimpanzees immunized with the homologous HCV envelope glycoproteins neutralized pseudotyped virus infectivity. Results from this study suggested a potential functional role for both the E1 and E2 glycoproteins in the infectivity of VSV/HCV pseudotyped virus in mammalian cells. These observations further suggest the importance of using both viral glycoproteins in a candidate subunit vaccine and the potential for using a VSV/HCV pseudotyped virus to determine HCV neutralizing antibodies.

Delayed VO2 kinetics during ramp exercise: a criterion for cardiopulmonary exercise capacity in chronic heart failure

PURPOSE

Kinetics of VO2 at onset of constant work rate exercise was previously shown to be slowed in patients with chronic heart failure (CHF) compared with that in healthy normals. Because bicycle ergometry with ramp protocol is usually used for exercise testing with CHF patients, it would be of practical importance if it can be shown that a delay in the time interval of linear increase of VO2 (TILIV) to work rate occurs after beginning ramp exercise. Data of central hemodynamics (CHF) and noninvasive cardiopulmonary parameters (CHF, normals) should also correlate with VO2 delay time if this parameter is related to cardiopulmonary exercise capacity.

METHODS

Fifteen males with CHF (mean +/- SEM: age 52 +/- 2 yr; ejection fraction 32 +/- 4%; peak cardiac index 3.9 +/- 0.3 L x m(-2) x min(-1)) and 28 healthy males (50 +/- 1 yr) were assessed. During ramp bicycle ergometry (3 min unloaded, work rate increments of 12.5 W x min(-1)), VO2 was measured breath by breath.

RESULTS

After the onset of ramp exercise, there was a difference in the TILIV between patients and normals (83.7 +/- 3.6 vs 66.8 +/- 2.9 s; P < 0.001). Significant differences between both groups were also found for VO2 at ventilatory threshold (VT) (10.1 +/- 0.1 vs 15.2 +/- 0.7 mL x kg(-1) x min(-1); P < 0.0001), VO2 at VT relative to predicted VT (58 +/- 4 vs 97 +/- 4%; P < 0.0001), peak VO2 (13.2 +/- 1.0 vs 34 +/- 1.4 mL x kg(-1) x min(-1), P < 0.001), and increase of systolic blood pressure (36 +/- 7 vs 71 +/- 5 mm Hg; P < 0.0001). In CHF, the TILIV correlated significantly with peak cardiac index and VO2 at VT (r = -0.71; P < 0.005 each), relative value of VO2/kg at VT (r = -0.61; P < 0.03), peak VO2/kg (r = -0.63; P < 0.01), and increase of systolic blood pressure (r = -0.52; P < 0.02). In the normals only VO2/kg at VT correlated significantly with TILIV (r = -0.41; P < 0.03). In patients, stepwise regression analysis identified three predictors which could explain 79% of the variance of TILIV: VO2/kg at VT (r2 = 0.51), peak cardiac index (r2 = 0.20), and peak VO2/kg (r2 = 0.08).

CONCLUSION

TILIV, determined at the onset of ramp exercise, is prolonged in CHF patients compared with that in normals and reflects severity of functional impairment because of reduced cardiac index and aerobic capacity. TILIV can provide information about changes in cardiopulmonary exercise capacity and thus can be used for follow-up and treatment studies in CHF.

Hepatitis C virus core protein represses p21WAF1/Cip1/Sid1 promoter activity

Hepatitis C virus (HCV) often causes a prolonged and persistent infection, and an association between hepatocellular carcinoma (HCC) and HCV infection has been noted. Recent experimental evidence using a cloned genomic region suggests that the putative core protein of HCV has numerous biological properties and is implicated as a viral factor for HCV mediated pathogenesis. WAF1/Cip1/Sid1 (p21) is the prototype of a family of proteins that inhibit cyclin-dependent kinases (CDK) and regulate cell cycle progression in eukaryotic cells. In this study, we have observed that the HCV core protein represses the transcriptional activity of the p21 promoter when tested separately by an in-vitro transient expression assay using murine fibroblasts (NIH3T3), human hepatocellular carcinoma (HepG2), and human cervical carcinoma (HeLa) cells. A deletion analysis of the p21 promoter suggested that the HCV core responsive region is located downstream of the p53 binding site. A gel mobility shift analysis showed that the HCV core protein does not bind directly to p21 regulatory sequences. Thus, the HCV core protein appears to act as an effector in the promotion of cell growth by repressing p21 transcription through unknown cellular factor(s).

ICAM-1 upregulation in distant tissues after hepatic ischemia/reperfusion: a clue to the mechanism of multiple organ failure

BACKGROUND/PURPOSE

Endothelial cell adhesion molecules (ECAMs) are felt to play an important role in ischemia/reperfusion (I/R) injury by causing adhesion of leukocytes to endothelial cells. It is possible that ECAMs play a role in multiple organ system failure. ICAM-1 is one of the adhesion molecules that has been shown to be upregulated in response to cytokines. This upregulation leads to leukocyte endothelial cell interaction (adhesion) and to neutrophil infiltration of the affected tissue. The purpose of our study was to measure ICAM-1 expression in the liver and other organs after hepatic ischemia/reperfusion (I/R).

METHODS

A laparotomy was performed on 14 Sprague-Dawley rats; 45 minutes of occlusive ischemia to the left lateral lobe was followed by 5 hours of reperfusion. The rat was injected with I125-labeled ICAM-1 MAb and I131-labeled nonbinding MAb (to control for nonspecific accumulation of ICAM-1 MAb). Entire organs were harvested and accumulated activity was measured in each organ. ICAM-1 levels were expressed as percent injected dose per gram of tissue. Control animals underwent sham laparotomy.

RESULTS

ICAM-1 was upregulated in the ischemic lobe of the liver, nonischemic lobe of the liver, heart, kidney, intestine, and pancreas. Up-regulation in the lung was not significant. Both the lung and liver had high constitutive levels of ICAM-1.

CONCLUSIONS

These data show that (1) significant hepatic upregulation of ICAM-1 after hepatic ischemia/reperfusion and (2) significant ICAM-1 upregulation in other tissues (heart, kidney, and intestine) after hepatic ischemia/reperfusion. The ICAM-1 upregulation in distant organs is likely mediated by cytokines such as tumor necrosis factor (TNF). These data show that leukocyte endothelial cell interactions in distant organs may be mediated by hepatic ischemia/reperfusion. This is a possible explanation for how failure of one organ can lead to failure of others in multiple organ system failure.

Inhibition of tumor necrosis factor (TNF-alpha)-mediated apoptosis by hepatitis C virus core protein

Hepatitis C virus (HCV) putative core protein has displayed many intriguing biological properties. Since tumor necrosis factor (TNF) plays an important role in controlling viral infection, in this study the effect of the core protein was investigated on the TNF-alpha induced apoptosis of human breast carcinoma cells (MCF7). HCV core protein when expressed inhibited TNF-alpha-induced apoptotic cell death unlike the control MCF7 cells, as determined by cell viability and DNA fragmentation analysis. Additionally, HCV core protein blocked the TNF-induced proteolytic cleavage of the death substrate poly(ADP-ribose) polymerase from its native 116-kDa protein to the characteristic 85-kDa polypeptide. Results from this study suggest that the HCV core protein plays a role in the inhibition of TNF-alpha-mediated cell death. Thus, the ability of core protein to inhibit the TNF-mediated apoptotic signaling pathway may provide a selective advantage for HCV replication, allowing for evasion of host antiviral defense mechanisms.

[Improvement of aerobic capacity in chronic congestive heart failure. Which training method is appropriate?]

Standardized guidelines for exercise training for patients with chronic congestive heart failure (CHF) have not been established. In the past, CHF patients involved in exercise training studies demonstrated a wide range of cardiac and functional impairment, with an ejection fraction between 18 and 35% and a peak VO2 between 12.2 and 25.4 ml/kg/min on average. For determination of training intensity, a VO2 between 40 and 70% of peak VO2 and/or training heart rate between 60 and 80% of peak heart rate was used. There was also a wide range for frequency (between 3 and 7 times per week) and duration of training (between 20 and 60 min per session). For aerobic exercise training only continuous training methods were applied. We have developed a new interval training method which allows intense exercise stimuli on peripheral muscles with minimal cardiac strain. After only three weeks of training, the improvement in aerobic capacity was similar to that reported after longer training periods using continuous methods. To determine work rate for work phases of interval training, a special steep ramp test was developed. By analysis of acute physical responses to this testing procedure and to the interval training, both were proven to be tolerable in CHF patients, even if their ejection fraction is as low as 13%, or peak cardiac index not greater than 1.61/m2/min, and peak VO2 less than 8.5 ml/kg/min.

Seasonal variation of biochemical indexes of bone turnover: results of a population-based study

Biochemical markers of bone turnover have been shown to provide valuable information for the diagnosis and monitoring of metabolic bone disease. However, these dynamic indexes are influenced by a number of factors that need to be clearly identified to improve their clinical usefulness. To evaluate the contributions of anthropometric, life style, and environmental variables on bone turnover, biochemical markers of bone metabolism were determined in a population-based sample of 580 adults, aged 50-81 yr (297 men and 283 women). Subjects were recruited during 14 consecutive months within the framework of the European Vertebral Osteoporosis Study. Serum total and bone-specific alkaline phosphatase (S-BAP), serum C-terminal propeptide of type I collagen, and serum osteocalcin (S-OC) were measured as bone formation markers. Urinary total pyridinoline and deoxypyridinoline were included as bone resorption indexes. In females, serum levels of 25-hydroxyvitamin D3 were significantly higher (P < 0.01) in summer (May-September) than in winter (October-April), whereas no significant differences were found in males. In both sexes, no seasonal changes were seen in serum PTH. In males, serum total alkaline phosphatase (P < 0.01), S-BAP (P < 0.001), and S-OC (P < 0.05) were significantly higher in winter than in summer. During the same period, females had higher values of S-BAP (P < 0.05), S-OC (P < 0.01), and urinary pyridinoline and deoxypyridinoline (P < 0.001, respectively). Univariate analyses of the effects of life style habits on markers of bone metabolism revealed that in females, regular alcohol consumption and current smoking led to a suppression of markers of bone turnover, whereas in males, only alcohol intake was associated with such changes. In contrast, physical activity was associated with higher levels of bone formation markers and reduced levels of bone resorption indexes in both sexes. As shown by multivariate regression analyses, seasonal variations accounted for more of the variability in most biomarkers (up to 12%) than any of the other anthropometric or life style factors except age. This effect may be attributed to subclinical vitamin D deficiency during the winter period, which is common in countries of the northern hemisphere. We conclude that seasonal variation contributes significantly to the biological variability of bone turnover and needs consideration when interpreting the results of bone marker measurements.

Patient's view of dialysis care: development of a taxonomy and rating of importance of different aspects of care. CHOICE study. Choices for Healthy Outcomes in Caring for ESRD

Quality assessment efforts to enhance public accountability in dialysis care and to support provider efforts to improve care have lacked patient input. To develop brief patient evaluation or satisfaction surveys suitable for busy clinical settings, knowing patients' priorities can be helpful in deciding which aspects of care should be tracked. We conducted a study to identify salient attributes of dialysis care and to rank the importance of these attributes from the perspective of dialysis patients. We analyzed the content of patient focus group transcripts to characterize dialysis care from the patients' perspective. We then surveyed 86 patients to determine how patients would rank the importance of each aspect to quality of dialysis care. The 18 broad aspects of care identified in the focus group included: (1) care provided by nephrologists, (2) care provided by other physicians (nonnephrologists), (3) care provided by dialysis center nurses, (4) care provided by social workers and psychologists, (5) care provided by dieticians, (6) clergy, (7) care provided by technicians and physician assistants/nurse practitioners, (8) care provided by dialysis center staff in general, (9) supplies, (10) treatment choice and effectiveness, (11) patient education and training, (12) self-care, (13) dialysis machines, (14) unit environment and policies, (15) cost containment, (16) billing, (17) cost of care, and (18) health outcomes. Items ranked in the top 10 by both groups of patients included issues related to nephrologists, other doctors, nurses, and patient education and training. Compared with hemodialysis patients, peritoneal dialysis patients gave higher ratings to hospital doctors' and nurses' attention to cleanliness when working with access sites, how correct the nephrologist's instructions to patients are, whether emergency room doctors check with nephrologists, the amount of information patients get about their diet, and how well nurses answer patients' questions. Patients value certain aspects of dialysis care highly, and these aspects differed in some respects for the relatively small number of hemodialysis and peritoneal dialysis patients studied. Construction of brief questionnaires for quality assessment and assurance requires thoughtful consideration of what questions to include. Knowing patients' priorities regarding the most important aspects of care that have high potential for dissatisfaction may be helpful to continuous quality improvement of end-stage renal disease care.

Functional involvement of polypyrimidine tract-binding protein in translation initiation complexes with the internal ribosome entry site of foot-and-mouth disease virus

The synthesis of picornavirus polyproteins is initiated cap independently far downstream from the 5' end of the viral RNA at the internal ribosome entry site (IRES). The cellular polypyrimidine tract-binding protein (PTB) binds to the IRES of foot-and-mouth disease virus (FMDV). In this study, we demonstrate that PTB is a component of 48S and 80S ribosomal initiation complexes formed with FMDV IRES RNA. The incorporation of PTB into these initiation complexes is dependent on the entry of the IRES RNA, since PTB and IRES RNA can be enriched in parallel either in 48S or 80S ribosomal complexes by stage-specific inhibitors of translation initiation. The formation of the ribosomal initiation complexes with the IRES occurs slowly, is temperature dependent, and correlates with the incorporation of PTB into these complexes. In a first step, PTB binds to the IRES, and then the small ribosomal subunit encounters this PTB-IRES complex. Mutations in the major PTB-binding site interfere simultaneously with the formation of initiation complexes, translation efficiency, and PTB cross-linking. PTB stimulates translation directed by the FMDV IRES in a rabbit reticulocyte lysate depleted of internal PTB, and the efficiency of translation can be restored to the original level by the addition of PTB. These results indicate that PTB plays an important role in the formation of initiation complexes with FMDV IRES RNA and in stimulation of internal translation initiation with this picornavirus.

Antisense suppression of 4-coumarate:coenzyme A ligase activity in Arabidopsis leads to altered lignin subunit composition

The phenylpropanoid enzyme 4-coumarate:coenzyme A ligase (4CL) is considered necessary to activate the hydroxycinnamic acids for the biosynthesis of the coniferyl and sinapyl alcohols subsequently polymerized into lignin. To clarify the role played by 4CL in the biosynthesis of the guaiacyl (G) and syringyl (S) units characteristic of angiosperm lignin, we generated 4CL antisense Arabidopsis lines having as low as 8% residual 4CL activity. The plants had decreases in thioglycolic acid-extractable lignin correlating with decreases in 4CL activity. Nitrobenzene oxidation of cell walls from bolting stems revealed a significant decrease in G units in 4CL-suppressed plants; however, levels of S lignin units were unchanged in even the most severely 4CL-suppressed plants. These effects led to a large decrease in the G/S ratio in these plants. Our results suggest that an uncharacterized metabolic route to sinapyl alcohol, which is independent of 4CL, may exist in Arabidopsis. They also demonstrate that repression of 4CL activity may provide an avenue to manipulate angiosperm lignin subunit composition in a predictable manner.