End-stage renal disease in African Americans with lupus nephritis is associated with APOL1

OBJECTIVE

Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus (SLE) that exhibits familial aggregation and may progress to end-stage renal disease (ESRD). LN is more prevalent among African Americans than among European Americans. This study was undertaken to investigate the hypothesis that the apolipoprotein L1 gene (APOL1) nephropathy risk alleles G1/G2, common in African Americans and rare in European Americans, contribute to the ethnic disparity in risk.

METHODS

APOL1 G1 and G2 nephropathy alleles were genotyped in 855 African American SLE patients with LN-ESRD (cases) and 534 African American SLE patients without nephropathy (controls) and tested for association under a recessive genetic model, by logistic regression.

RESULTS

Ninety percent of the SLE patients were female. The mean ± SD age at SLE diagnosis was significantly lower in LN-ESRD cases than in SLE non-nephropathy controls (27.3 ± 10.9 years versus 39.5 ± 12.2 years). The mean ± SD time from SLE diagnosis to development of LN-ESRD in cases was 7.3 ± 7.2 years. The G1/G2 risk alleles were strongly associated with SLE-ESRD, with 25% of cases and 12% of controls having 2 nephropathy alleles (odds ratio [OR] 2.57, recessive model P = 1.49 × 10(-9)), and after adjustment for age, sex, and ancestry admixture (OR 2.72, P = 6.23 × 10(-6)). The age-, sex-, and admixture-adjusted population attributable risk for ESRD among patients with G1/G2 polymorphisms was 0.26, compared to 0.003 among European American patients. The mean time from SLE diagnosis to ESRD development was ∼2 years earlier among individuals with APOL1 risk genotypes (P = 0.01).

CONCLUSION

APOL1 G1/G2 alleles strongly impact the risk of LN-ESRD in African Americans, as well as the time to progression to ESRD. The high frequency of these alleles in African Americans with near absence in European Americans explains an important proportion of the increased risk of LN-ESRD in African Americans.

Identification of sex pheromones of two sibling species in dingy cutworm complex,Feltia jaculifera (GN.) (Lepidoptera: Noctuidae)

The sex pheromone components of the two sibling species of the dingy cutworm that occur on the prairies of western Canada were identified in abdomen-tip extracts from calling female moths. Three monounsaturated acetates, (Z)-7-dodecenyl acetate, (Z)-9-tetradecenyl acetate, and (Z)-11-hexadecenyl acetate, are common to both species in ratios of 100∶13∶3 for species A and 0.3∶0.5∶100 for species B. The most effective synthetic blends for the attraction of male moths in the field consisted of these three components in ratios of 10∶1∶0 at 8.8Μg/lure for species A and 1∶1∶2000 at 500Μg/lure for species B. The addition of Z5-12∶Ac to either blend reduced the catches and the addition of Z7-12∶OH orZ11-16∶OH to the three-component blend reduced the catches of species B males. The species are morphologically indistinguishable, but the identity of the males attracted to the synthetic blends could be confirmed by their antennal responses to a test blend of the three components using a GC-EAD system. Both synthetic attractant blends are competitive with females and will be useful for studying the distribution, biology, and relative abundances of the two species.

Glycated albumin, not hemoglobin A1c, predicts cardiovascular hospitalization and length of stay in diabetic patients on dialysis

BACKGROUND

The utility of glycated hemoglobin (HbA1c) and glycated albumin (GA) in diabetic dialysis patients remains unknown. GA was previously associated with all-cause hospitalization and patient survival. Relationships between GA, HbA1c, and casual plasma glucose (PG) with cause-specific cardiovascular (CV) disease, infectious disease (ID), and vascular access- (VA) related hospitalization rates and length of stay (LOS) were assessed.

METHODS

444 prevalent diabetic dialysis patients had monthly PG, quarterly GA, and all HbA1c values recorded for 2.33 years; hospitalizations within 17 and 30 days of testing were evaluated. Best-fit, time-dependent Cox models were constructed in unadjusted, case-mix-adjusted (age, sex, race, BMI, diabetes duration, dialysis vintage), and case-mix- plus lab-adjusted (hemoglobin, albumin, phosphorus) models.

RESULTS

Mean ± SD diabetes duration was 18.5 ± 10.8 years and dialysis vintage 2.9 ± 2.6 years. In fully adjusted models, CV hospitalization rates were associated with increasing GA (HR 1.32; 95% CI 1.11-1.57; p = 0.002 at 17 days; HR 1.21; p = 0.02 at 30 days) and PG (HR 1.10; 95% CI 1.02-1.17; p = 0.01 at 17 days; HR 1.07; p = 0.03 at 30 days), not HbA1c (HR 1.24; 95% CI 0.89-1.73; p = 0.21 at 17 days; HR 1.26; p = 0.10 at 30 days). LOS for CV admissions was positively associated with GA (HR 1.18; 95% CI 1.01-1.39; p = 0.03), not PG (HR 1.04; 95% CI 0.99-1.10; p = 0.15) or HbA1c (HR 1.03; 95% CI 0.92-1.15; p = 0.21). Admissions due to ID and VA complications (and LOS) did not correlate with these assays.

CONCLUSIONS

Improved glycemic control based on GA and PG predicted CV-related hospitalizations; GA also predicted CV hospitalization LOS. HbA1c did not predict cause-specific hospitalizations in dialysis populations.

Glycated albumin and risk of death and hospitalizations in diabetic dialysis patients

BACKGROUND AND OBJECTIVES

Relative to hemoglobin (Hb) A(₁c), glycated albumin (GA) more accurately reflects glycemic control in patients with diabetes mellitus and ESRD. We determined the association between GA, HbA(₁c), and glucose levels with survival and hospitalizations in diabetic dialysis patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Quarterly GA levels were measured for up to 2.33 years in 444 prevalent patients with diabetes and ESRD. Proportional hazard time-dependent covariate models were computed with adjustment for demographic characteristics, comorbidities, and laboratory variables. Similar analyses were performed for available HbA(₁c) and monthly random serum glucose determinations.

RESULTS

The participants were 53% male, 54% African American, 43% Caucasian, 90% on hemodialysis, with a mean (SD) age of 62 (12) years and median follow-up duration of 2.25 years. GA and HbA(₁c) mean ± SD 21.5% ± 6.0%, median 20.4% and mean ± SD 6.9% ± 6.6%, median 1.6%, respectively. There were 156 deaths during the observation period. In best-fit models, predictors of death included increasing GA, increasing age, presence of peripheral vascular disease, decreasing serum albumin, and decreasing hemoglobin concentrations. HbA(1c) and random serum glucose concentrations were not predictive of survival. Increasing GA levels were associated with hospitalization in the 17 days after measurement, whereas HbA(₁c) was not.

CONCLUSIONS

In contrast to the HbA(₁c) and random serum glucose values, GA accurately predicts the risk of death and hospitalizations in patients with diabetes mellitus and ESRD. The GA assay should be considered by clinicians who care for patients with diabetes on dialysis.

Comparison of glycated albumin and hemoglobin A1c concentrations in diabetic subjects on peritoneal and hemodialysis

BACKGROUND

Relative to hemoglobin A(1c) (HbA(1c)), percentage of glycated albumin (GA%) more accurately reflects recent glycemic control in diabetic hemodialysis (HD) patients.

METHODS

To determine the accuracy of glycemic assays in a larger sample including patients on peritoneal dialysis (PD), HbA(1c) and GA% were measured in 519 diabetic subjects: 55 on PD, 415 on HD, and 49 non-nephropathy controls.

RESULTS

Mean +/- SD serum glucose levels were higher in HD and PD patients relative to non-nephropathy controls (HD 169.7 +/- 62 mg/dL, PD 168.6 +/- 66 mg/dL, controls 146.1 +/- 66 mg/dL; p = 0.03 HD vs controls, p = 0.13 PD vs controls). GA% was also higher in HD and PD patients (HD 20.6% +/- 8.0%, PD 19.0% +/- 5.7%, controls 15.7% +/- 7.7%; p < 0.02 HD vs controls and PD vs controls). HbA(1c) was paradoxically lower in dialysis patients (HD 6.78% +/- 1.6%, PD 6.87% +/- 1.4%, controls 7.3% +/- 1.4%; p = 0.03 HD vs controls, p = 0.12 PD vs controls). The serum glucose/HbA(1c) ratio differed significantly between dialysis patients and controls (p < 0.0001 HD vs controls, p = 0.002 PD vs controls), while serum glucose/GA% ratio was similar across groups (p = 0.96 HD vs controls, p = 0.64 PD vs controls). In best-fit multivariate models with HbA(1c) or GA% as outcome variable, dialysis status was a significant predictor of HbA(1c) but not GA%.

CONCLUSIONS

The relationship between HbA(1c) and GA% differs in diabetic patients with end-stage renal disease who perform either PD or HD compared to those without nephropathy. HbA(1c) significantly underestimates glycemic control in peritoneal and hemodialysis patients relative to GA%.

Relationship between assays of glycemia in diabetic subjects with advanced chronic kidney disease

BACKGROUND

Relative to hemoglobin A(1c) (HbA(1c)), glycated albumin (GA) more accurately reflects recent glycemic control in diabetic patients on hemodialysis and peritoneal dialysis. These assays have yet to be compared in patients with advanced chronic kidney disease (CKD).

METHODS

HbA(1c) and GA were simultaneously measured in 303 diabetic subjects: 70 with CKD prior to dialysis (CKD-stage 4), 184 with CKD after transplantation (TXP-stage 3) and 49 non-nephropathy controls.

RESULTS

Mean estimated GFR was 76, 46 and 26 ml/min in controls, TXP-3 and CKD-4 cases, respectively. Mean (SD) HbA(1c) (%) and GA (%) concentrations were 7.30 (1.40) and 16.8 (4.9) in controls, 7.28 (1.66) and 21.5 (6.4) in CKD-4 cases, and 7.21 (1.62) and 21.2 (5.5) in TXP-3 cases, respectively. The GA:HbA(1c) ratio differed significantly between non-nephropathy controls and both groups of CKD patients (both p < 0.001), but not between CKD-4 and TXP-3 cases (p = 0.92). The glucose:HbA(1c) ratio was inversely associated with GFR in all 254 nephropathy cases (r = -0.13; p = 0.04), while glucose:GA did not vary significantly based upon GFR (r = -0.08; p = 0.24).

CONCLUSIONS

The relationship between glycated albumin and HbA(1c) is influenced by the presence of reduced GFR in diabetic patients with CKD. The accuracy of the HbA(1c) assay in diabetic subjects with severe nephropathy requires further investigation, although HbA(1c) performs relatively well with milder CKD.

Comparison of glycated albumin and hemoglobin A(1c) levels in diabetic subjects on hemodialysis

Glycated albumin is thought to more accurately reflect glycemic control in diabetic hemodialysis patients than hemoglobin A(1c) because of shortened red cell survival. To test this, glycated hemoglobin and albumin levels were measured in blood samples collected from 307 diabetic subjects of whom 258 were on hemodialysis and 49 were without overt renal disease. In diabetic subjects with renal disease, relative to those without, the mean serum glucose and glycated albumin concentrations were significantly higher while hemoglobin A(1c) tended to be lower. The glycated albumin to hemoglobin A(1c) ratio was significantly increased in dialysis patients compared with the controls. Hemoglobin A(1c) was positively associated with hemoglobin and negatively associated with the erythropoietin dose in hemodialysis patients, whereas these factors and serum albumin did not significantly impact glycated albumin levels. Using best-fit multivariate models, dialysis status significantly impacted hemoglobin A(1c) levels without a significant effect on glycated albumin. Our results show that in diabetic hemodialysis patients, hemoglobin A(1c) levels significantly underestimate glycemic control while those of glycated albumin more accurately reflect this control.

Effect of wheat stem sawfly damage on yield and quality of selected Canadian spring wheat

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), has reached outbreak status at most locations in the southern Canadian prairies. Solid-stemmed wheat, Triticum aestivum L., cultivars, which are less susceptible to damage, remain the primary management option. This article quantifies the effect of wheat stem sawfly damage on grain yield and quality at harvest and determines how cultivar selection affects harvest losses. Solid-stemmed cultivars were compared with hollow-stemmed cultivars and with blends of a 1:1 ratio of each. The hollow-stemmed cultivars with the exception of'McKenzie', which had intermediate levels of stem cutting, were all significantly more susceptible to stem cutting than solid-stemmed cultivars. Cultivar blends had lower damage but were still significantly higher than the solid-stemmed cultivars. The solid-stemmed 'AC Eatonia' and 'AC Abbey' had the lowest levels of stem cutting and ranked second and third overall for yield in 2001 and 2002. McKenzie ranked first, which reflects its yield potential in combination with its partial resistance to stem cutting. Lower cutting in AC Eatonia, AC Abbey, McKenzie, and the blend of AC Abbey/ McKenzie was significantly correlated with lower grain losses. Grain lost at harvest has major economic implications if sawfly pressure is moderate to high and susceptible cultivars predominate.

Expression of a Bacillus thuringiensis delta-endotoxin gene by Bacillus pumilus

The delta-endotoxin genes from Bacillus thuringiensis were introduced into a rhizosphere-inhabiting Bacillus pumilus isolate to create a delta-endotoxin expression and delivery system for subterranean feeding insects such as the larvae of pale western cutworm (Agrotis orthogonia Morrison (Lepidoptera: Noctuidae)). Preliminary experiments indicated that Bacillus thuringiensis subsp. kurstaki cultures were toxic to pale western cutworm larvae. Three different cry genes from Bacillus thuringiensis subsp. kurstaki were cloned into high and low copy number vectors and mated into Bacillus pumilus RB8. When carried on high copy number vectors, cry genes appeared to inhibit sporulation and delta-endotoxin production in Bacillus pumilus RB8 cultures, since microscopic examination of these cultures revealed that < 0.1% of the cells of late stationary phase cultures had sporulated and produced parasporal inclusions. On low copy number vectors, the cry genes did not inhibit sporulation; however, production of delta-endotoxins was undetectable. Using a heat shock regime for enrichment of sporogenous crystalliferous variants, a Bacillus pumilus isolate, carrying cryIA(c) on a high copy number plasmid, was obtained in which high level delta-endotoxin production occurred concomitant with sporulation. Synthesis of functional delta-endotoxin by this strain was confirmed by Western blot analysis and bioassay with pale western cutworm larvae. These results show that rhizosphere-inhabiting bacilli are indeed a potential route for introduction of delta-endotoxins to the root environment for biocontrol purposes.

A new glandular organ in some toxic caterpillars

The nodes formed by the mid-ventral tracheal anastomoses in abdominal segments 3-6 are modified into conspicuous glandular organs in larvae of certain Lepidoptera. They comprise clusters of extremely large cells penetrated by an extensive lacunar system opening onto the tracheal wall. These cells appear to sequester substances from the haemolymph which may be conjugated with a lipoid synthesized within them and the product excreted into the lacunar system, ultimately passing into the tracheal lumen.

Morphology and Ultrastructure of the Intestine in a Plant-Parasitic Nematode, Tylenchorhynchus dubius

An unusual feature of the intestine in Tylenchorhynchus dubius is the presence, within the intestinal cytoplasm, of an extensive system of fibrillar bundles consisting of thin (14 nm diam) filaments and thick (70-90 nm diam), rod-like elements arranged in closely packed arrays. The larger of the fibrillar bundles, for which the term "intestinal fasciculi" is proposed, are evident in whole mounts and apparently correspond to the lateral or sinuous canals described in some other tylenchids. The nature and function of fasciculi are not known, but some possibilities are considered. Fasciculi were found in at least seven other species of Tylenchorhynchus. The intestinal cytoplasm also contains the usual sub cellular organelles and large amounts of reserve materials in the form of particulate glycogen and three types of globules. The surface of the cells bordering the lumen is elaborated into numerous microvilli which have central filaments and often bear regular external projections. Although terminal bars delimit the apical margins between cells, the frequent lack of complete lateral boundaries and extensive length of the fasciculi indicate that the intestinal epithelium is a multinucleate mosaic or syncytium.

Metamorphosis of the perirectal malpighian tubules in the mealworm Tenebrio molitor L. (Coleoptera, Tenebrionidae). II. Ultrastructure and role of autophagic vacuoles

The perirectal Malpighian tubules of T. molitor are highly specialized for ion and fluid transport. Although they survive metamorphosis, being similar in structure and function in both larva and adult, they undergo a sequence of dramatic alterations in subcellular organization. In the early stages of metamorphosis there is a phase of dedifferentiation during which the perirectal tubule cells undergo degenerative changes. The highly specialized brush border, which in the larva is formed of closely packed microvilli containing mitochondria, is partially broken down and a large number of mitochondria undergo autophagic isolation and digestion. A conspicuous result of the autophagic processes is the accumulation of membrane lipid within autophagic vacuoles which are eventually transformed into 'osmiophilic bodies.' During the later stages of metamorphosis the cells progressively redifferentiate and the brush border is reconstituted. The number of osmiophilic bodies declines markedly, concomitant with an apparent increase in the number of mitochondria.

Metamorphosis of the perirectal Malpighian tubules in the mealworm Tenebrio molitor L. (Coleoptera, Tenebrionidae). I. Histology and histochemistry

The perirectal Malpighian tubules of both larva and adult T. molitor are highly specialized for a fluid transport role. Related to this function are a number of structural specializations, including a thick brush border which lines the lumen of the tubules. The brush border consists of closely packed microvilli containing mitochondria. Although the perirectal tubules survive the transformation from larva to adult they undergo at the cellular level a sequence of dramatic changes. During the early stages of metamorphosis there is a phase of dedifferentiation and autolysis involving the partial breakdown of the brush border and the destruction of large numbers of mitochondria. A conspicuous cytological manifestation of these processes is the transfer of membrane lipids from the brush border into intracellular osmiophilic bodies (autolysosomes). During the later stages of metamorphosis, i.e. adult development, the cells progressively redifferentiate. As the brush border is rebuilt there is an increase in the number of mitochondria concomitant with a decline in the number of osmiophilic bodies, indicating that the membrane lipid is reutilized for mitochondrial genesis.The results show that the processes of isolation and digestion of mitochondria, the accumulation and retention of valuable breakdown products, and their subsequent reutilization are integral parts of the economy of the perirectal tubule cells during metamorphosis.

A rickettsialike microorganism in Dahlbominus fuscipennis (Zett.) (Hymenoptera, Eulophidae): observations on its occurrence and ultrastructure

An intracellular microorganism found in D. fuscipennis exhibits the basic morphology characteristic of rickettsiae. It is regularly present in the gonads and abdominal ganglia, less frequently in other tissues. The rickettsia has no overt cytopathic effect in host cells, does not noticeably affect the fitness of the host, and is likely transmitted transovarially. On the basis of arthropod association, morphology, and relationship to the host cell the rickettsia resembles members of the genus Wolbachia. Its relationship with the host and the significance of a host-provided membrane enclosing each rickettsia are discussed.