The optic nerve lamina region is a neural progenitor cell niche.

Retinal ganglion cell axons forming the optic nerve (ON) emerge unmyelinated from the eye and become myelinated after passage through the optic nerve lamina region (ONLR), a transitional area containing a vascular plexus. The ONLR has a number of unusual characteristics: it inhibits intraocular myelination, enables postnatal ON myelination of growing axons, modulates the fluid pressure differences between eye and brain, and is the primary lesion site in the age-related disease open angle glaucoma (OAG). We demonstrate that the human and rodent ONLR possesses a mitotically active, age-depletable neural progenitor cell (NPC) niche, with unique characteristics and culture requirements. These NPCs generate both forms of macroglia: astrocytes and oligodendrocytes, and can form neurospheres in culture. Using reporter mice with SOX2-driven, inducible gene expression, we show that ONLR-NPCs generate macroglial cells for the anterior ON. Early ONLR-NPC loss results in regional dysfunction and hypomyelination. In adulthood, ONLR-NPCs may enable glial replacement and remyelination. ONLR-NPC depletion may help explain why ON diseases such as OAG progress in severity during aging.

A phase II multicenter trial of hyperCVAD MTX/Ara-C and rituximab in patients with previously untreated mantle cell lymphoma; SWOG 0213.

BACKGROUND: Rituximab-hyper-CVAD alternating with rituximab-high-dose methotrexate and cytarabine is a commonly utilized regimen in the United States for mantle cell lymphoma (MCL) based on phase II single institutional data. To confirm the clinical efficacy of this regimen and determine its feasibility in a multicenter study that includes both academic and community-based practices, a phase II study of this regimen was conducted by SWOG. PATIENTS AND METHODS: Forty-nine patients with advanced stage, previously untreated MCL were eligible. The median age was 57.4 years (35-69.8 years). RESULTS: Nineteen patients (39%) did not complete the full scheduled course of treatment due to toxicity. There was one treatment-related death and two cases of secondary myelodysplastic syndrome (MDS). There were 10 episodes of grade 3 febrile neutropenia, 19 episodes of grade 3 and 1 episode of grade 4 infection. With a median follow-up of 4.8 years, the median progression-free survival was 4.8 years (5.5 years for those ≤ 65 years) and the median overall survival (OS) was 6.8 years. CONCLUSIONS: Although this regimen is toxic, it is active for patients ≤ 65 years of age and can be given both at academic centers and in experienced community centers.

[Practical aspects for minimizing errors in the cross-cultural adaptation and validation of quality of life questionnaires]. / Cómo minimizar errores al realizar la adaptación transcultural y la validación de los cuestionarios sobre calidad de vida: aspectos prácticos.

BACKGROUND: The development and validation of questionnaires for evaluating quality of life (QoL) has become an important area of research. However, there is a proliferation of non-validated measuring instruments in the health setting that do not contribute to advances in scientific knowledge. AIMS: To present, through the analysis of available validated questionnaires, a checklist of the practical aspects of how to carry out the cross-cultural adaptation of QoL questionnaires (generic, or disease-specific) so that no step is overlooked in the evaluation process, and thus help prevent the elaboration of insufficient or incomplete validations. METHODS: We have consulted basic textbooks and Pubmed databases using the following keywords quality of life, questionnaires, and gastroenterology, confined to «validation studies¼ in English, Spanish, and Portuguese, and with no time limit, for the purpose of analyzing the translation and validation of the questionnaires available through the Mapi Institute and PROQOLID websites. RESULTS: A checklist is presented to aid in the planning and carrying out of the cross-cultural adaptation of QoL questionnaires, in conjunction with a glossary of key terms in the area of knowledge. The acronym DSTAC was used, which refers to each of the 5 stages involved in the recommended procedure. In addition, we provide a table of the QoL instruments that have been validated into Spanish. CONCLUSIONS: This article provides information on how to adapt QoL questionnaires from a cross-cultural perspective, as well as to minimize common errors.

Long-term administration of massive doses of Sn-protoporphyrin in anemic mutant mice (sphha/sphha).

The effects of long-term administration of very large doses of Sn-protoporphyrin on hematological indices, histological changes, plasma bilirubin levels, tissue heme oxygenase activity, and activities of heme biosynthetic enzymes, were examined in genetically anemic mutant mice with hemolytic anemia (sphha/sphha). Long-term weekly treatment with Sn-protoporphyrin (100 mumol/kg body weight for 32 wk) did not alter hematological indices, histological findings, or enzyme activities related to heme biosynthesis, even though it resulted in sustained decreases in microsomal heme oxygenase activity in the liver, kidney, and spleen, and a prolonged decrease in plasma bilirubin concentration. Inhibition of heme oxygenase did not alter the level of cytochrome P-450 in the liver and the kidney. The results indicate that long-term treatment with massive doses of Sn-protoporphyrin suppresses bilirubin formation but does not produce significant histopathological changes or appreciably interfere with heme synthesis, in this strain of genetically anemic mice. These findings provide further support for the idea that suppression of heme degradation to bile pigment by the inhibition of heme oxygenase may prove useful to the prevention of severe hyperbilirubinemia in humans.

Protocol-Driven Intensive Outpatient Management of Pregnant Patients With Symptomatic Coronavirus Disease 2019.

BACKGROUND: Reports of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have focused on pregnant women hospitalized due to moderate to severe coronavirus disease 2019 (COVID-19) or asymptomatic women diagnosed through universal screening at the time of obstetric admission. Many pregnant women who have symptomatic SARS-CoV-2 infection may not meet criteria for hospitalization; however, whether and how these women can be managed safely in outpatient setting is not well described. METHODS: We sought to describe the time to symptom and viral clearance and to identify predictors of hospitalization to better understand the safety of monitoring pregnant patients with symptomatic COVID-19 in the outpatient setting. We performed a retrospective cohort study of pregnant patients with symptomatic, confirmed COVID-19 illness at a large, academic medical center. Patients had systematic telehealth follow up by a clinician team to assess for symptoms, provide virtual prenatal care, and arrange in-person visits when appropriate in a dedicated outpatient center. Data were collected via chart abstraction. RESULTS: Of 180 pregnant patients presenting with symptoms and undergoing reverse-transcription polymerase chain reaction (RT-PCR) testing, 67 patients with confirmed COVID-19 infection were identified during the study period. Nineteen (28%) required acute care given worsening of COVID-19 symptoms, and 95% of these were directed to this acute care setting due to symptom severity telehealth evaluation. Nine women (13%) were admitted to the hospital given worsening symptoms, 3 required intensive care unit care, 2 required ventilatory support, and 2 required delivery. Women with the presenting symptoms of fever, cough, shortness of breath, chest pain, or nausea and vomiting were more likely to require admission. The median duration from initial positive test to RT-PCR viral clearance was 26 days. Disease progression, time to viral clearance, and duration of symptoms did not vary significantly by trimester of infection. CONCLUSIONS: Management of the majority of pregnant women with symptomatic COVID-19 illness can be accomplished in the outpatient setting with intensive and protocol-driven monitoring for symptom progression.

Bortezomib in patients with relapsed or refractory mantle cell lymphoma: updated time-to-event analyses of the multicenter phase 2 PINNACLE study.

BACKGROUND: We previously reported results of the phase 2, multicenter PINNACLE study, which confirmed the substantial single-agent activity of bortezomib in patients with relapsed or refractory mantle cell lymphoma (MCL). MATERIALS AND METHODS: We report updated time-to-event data, in all patients and by response to treatment, after extended follow-up (median 26.4 months). RESULTS: Median time to progression (TTP) was 6.7 months. Median time to next therapy (TTNT) was 7.4 months. Median overall survival (OS) was 23.5 months. In responding patients, median TTP was 12.4 months, median duration of response (DOR) was 9.2 months, median TTNT was 14.3 months, and median OS was 35.4 months. Patients achieving complete response had heterogeneous disease characteristics; among these patients, median TTP and DOR were not reached, and median OS was 36.0 months. One-year survival rate was 69% overall and 91% in responding patients. Median OS from diagnosis was 61.1 months, after median follow-up of 63.7 months. Activity was seen in patients with refractory disease and patients relapsing following high-intensity treatment. Toxicity was generally manageable. CONCLUSIONS: Single-agent bortezomib is associated with lengthy responses and notable survival in patients with relapsed or refractory MCL, with considerable TTP and TTNT in responding patients, suggesting substantial clinical benefit.

Molecular and ultrastructural defects in a Drosophila myosin heavy chain mutant: differential effects on muscle function produced by similar thick filament abnormalities.

We have determined the molecular defect of the Drosophila melanogaster myosin heavy chain (MHC) mutation Mhc and the mutation's effect on indirect flight muscle, jump muscle, and larval intersegmental muscle. We show that the Mhc1 mutation is essentially a null allele which results in the dominant-flightless and recessive-lethal phenotypes associated with this mutant (Mogami, K., P. T. O'Donnell, S. I. Bernstein, T. R. F. Wright, C. P. Emerson, Jr. 1986. Proc. Natl. Acad. Sci. USA. 83:1393-1397). The mutation is a 101-bp deletion in the MHC gene which removes most of exon 5 and the intron that precedes it. S1 nuclease mapping indicates that mutant transcripts follow two alternative processing pathways. Both pathways result in the production of mature transcripts with altered reading frames, apparently yielding unstable, truncated MHC proteins. Interestingly, the preferred splicing pathway uses the more distal of two available splice donor sites. We present the first ultrastrutural characterization of a completely MHC-null muscle and show that it lacks any discernable thick filaments. Sarcomeres in these muscles are completely disorganized suggesting that thick filaments play a critical role in sarcomere assembly. To understand why the Mhc1 mutation severely disrupts indirect flight muscle and jump muscle function in heterozygotes, but does not seriously affect the function of other muscle types, we examined the muscle ultrastructure of Mhc1/+ heterozygotes. We find that these organisms have a nearly 50% reduction in the number of thick filaments in indirect flight muscle, jump muscle, and larval intersegmental muscle. In addition, aberrantly shaped thick filaments are common in the jump muscle and larval intersegmental muscle. We suggest that the differential sensitivity of muscle function to the Mhc1 mutation is a consequence of the unique myofilament arrays in each of these muscles. The highly variable myofilament array of larval intersegmental muscle makes its function relatively insensitive to changes in thick filament number and morphology. Conversely, the rigid double hexagonal lattice of the indirect flight muscle, and the organized lattice of the jump muscle cannot be perturbed without interfering with the specialized and evolutionarily more complex functions they perform.

Isolation and partial characterization of Drosophila myoblasts from primary cultures of embryonic cells.

We describe a method for preparing highly enriched cultures of Drosophila myoblasts from a heterogeneous cell population derived from gastrulating embryos. Enriched cultures are prepared by plating this heterogeneous population of cells in medium from which much of the free calcium is chelated by ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetraacetate (EGTA). Adhesion of myoblasts to tissue culture plastic is better than that of other cell types when plated in this medium. Data concerning cell identity, timing of S phase, and fusion kinetics document the degree of enrichment for myogenic cells and illustrate their synchronous differentiation in vitro.

Specific myosin heavy chain mutations suppress troponin I defects in Drosophila muscles.

We show that specific mutations in the head of the thick filament molecule myosin heavy chain prevent a degenerative muscle syndrome resulting from the hdp2 mutation in the thin filament protein troponin I. One mutation deletes eight residues from the actin binding loop of myosin, while a second affects a residue at the base of this loop. Two other mutations affect amino acids near the site of nucleotide entry and exit in the motor domain. We document the degree of phenotypic rescue each suppressor permits and show that other point mutations in myosin, as well as null mutations, fail to suppress the hdp2 phenotype. We discuss mechanisms by which the hdp2 phenotypes are suppressed and conclude that the specific residues we identified in myosin are important in regulating thick and thin filament interactions. This in vivo approach to dissecting the contractile cycle defines novel molecular processes that may be difficult to uncover by biochemical and structural analysis. Our study illustrates how expression of genetic defects are dependent upon genetic background, and therefore could have implications for understanding gene interactions in human disease.

The influence of light on cone disk shedding in the lizard, Sceloporus occidentalis.

The lizard, Sceloporus occidentalis has an all-cone retina. In lizards maintained on a 12-h light:12-h dark (12L:12D) cycle, a burst of cone outer segment (COS) shedding occurs 2 h after light offset (1400 h circadian time) (Young, R.W., 1977, J. Ultrastruct. Res. 61:172-72). In this investigation, we studied the effect of different lighting regimes on the pattern of cone disk shedding in this species. When lizards entrained to a 12L:12D cycle are kept in constant darkness (DD), the shedding peak is advanced approximately 2 h and the magnitude of shedding is reduced to 30% of control. COS increased in mean length from 12 micron in controls to 14 micron after one cycle in DD and maintained this length during a second cycle in DD. In constant light (LL), disk shedding was damped to approximately 10% of control values. Shedding synchrony in LL was also perturbed and therefore cyclic shedding bursts could not be distinguished. During LL there was a much larger increase in COS mean length than in DD. After one cycle of LL, COS length was 15 micron and after two cycles COS length exceeded 17 micron. When lizards entrained to 12L:12D are shifted to a 6L:18D regimen, the first shedding cycle is biphasic. The first peak of 5% shedding occurs 2 h after light offset whereas a second larger peak (13%) occurs according to the entrained schedule (1400 h). This manipulation separates out a dark-triggered and circadian shedding component, which is normally superimposed in lizards entrained to a 12L:12D cycle. When entrained lizards are placed in 36 h of LL followed by light offset, the peak shedding response after light offset is double the control response (53% vs. 27%). After 30 h of LL (lights off 90 degrees out of phase), there is a biphasic shedding response similar to the 6L:18D regimen although this time the dark-triggered shedding component is greater in magnitude then the circadian component. COS turnover is estimated by extrapolating from COS mean length increases during LL. From this method we obtained a 2.7-micron increase in COS length during each day in LL. If COS growth is not augmented during LL, this would yield a 4-5-d turnover time for the average 12.5-micron COS.

Transformation of Drosophila melanogaster with the wild-type myosin heavy-chain gene: rescue of mutant phenotypes and analysis of defects caused by overexpression.

We have transformed Drosophila melanogaster with a genomic construct containing the entire wild-type myosin heavy-chain gene, Mhc, together with approximately 9 kb of flanking DNA on each side. Three independent lines stably express myosin heavy-chain protein (MHC) at approximately wild-type levels. The MHC produced is functional since it rescues the mutant phenotypes of a number of different Mhc alleles: the amorphic allele Mhc1, the indirect flight muscle and jump muscle-specific amorphic allele Mhc10, and the hypomorphic allele Mhc2. We show that the Mhc2 mutation is due to the insertion of a transposable element in an intron of Mhc. Since a reduction in MHC in the indirect flight muscles alters the myosin/actin protein ratio and results in myofibrillar defects, we determined the effects of an increase in the effective copy number of Mhc. The presence of four copies of Mhc results in overabundance of the protein and a flightless phenotype. Electron microscopy reveals concomitant defects in the indirect flight muscles, with excess thick filaments at the periphery of the myofibrils. Further increases in copy number are lethal. These results demonstrate the usefulness and potential of the transgenic system to study myosin function in Drosophila. They also show that overexpression of wild-type protein in muscle may disrupt the function of not only the indirect flight but also other muscles of the organism.

Analysis of Drosophila paramyosin: identification of a novel isoform which is restricted to a subset of adult muscles.

In this report we show that Drosophila melanogaster muscles contain the standard form of the thick filament protein paramyosin, as well as a novel paramyosin isoform, which we call miniparamyosin. We have isolated Drosophila paramyosin using previously established methods. This protein is approximately 105 kD and cross-reacts with polyclonal antibodies made against Caenorhabditis elegans or Heliocopris dilloni paramyosin. The Heliocopris antibody also cross-reacts with a approximately 55-kD protein which may be miniparamyosin. We have cloned and sequenced cDNA's encoding both Drosophila isoforms. Standard paramyosin has short nonhelical regions at each terminus flanking the expected alpha-helical heptad repeat seen in other paramyosins and in myosin heavy chains. The COOH-terminal 363 amino acids are identical in standard and miniparamyosin. However, the smaller isoform has 114 residues at the NH2 terminus that are unique as compared to the current protein sequence data base. The paramyosin gene is located at chromosome position 66E1. It appears to use two promoters to generate mRNA's that have either of two different 5' coding sequences joined to common 3' exons. Each protein isoform is encoded by two transcripts that differ only in the usage of polyadenylation signals. This results in four size classes of paramyosin mRNA which are expressed in a developmentally regulated pattern consistent with that observed for other muscle-specific RNA's in Drosophila. In situ hybridization to Drosophila tissue sections shows that standard paramyosin is expressed in all larval and adult muscle tissues whereas miniparamyosin is restricted to a subset of the adult musculature. Thus miniparamyosin is a novel muscle-specific protein that likely plays a role in thick filament structure or function in some adult muscles of Drosophila.

Evidence that microtubules do not mediate opsin vesicle transport in photoreceptors.

The organization of the rod photoreceptor cytoskeleton suggests that microtubules (MTs) and F actin are important in outer segment (OS) membrane renewal. We studied the role of the cytoskeleton in this process by first quantifying OS membrane assembly in rods from explanted Xenopus eyecups with a video assay for disc morphogenesis and then determining if the rate of assembly was reduced after drug disassembly of either MTs or F actin. Membrane assembly was quantified by continuously labeling newly forming rod OS membranes with Lucifer Yellow VS (LY) and following the tagged membranes' distal displacement along the OS. LY band displacement displayed a linear increase over 16 h in culture. These cells possessed a longitudinally oriented network of ellipsoid MTs between the sites of OS protein synthesis and OS membrane assembly. Incubation of eyecups in nocodazole, colchicine, vinblastine, or podophyllotoxin disassembled the ellipsoid MTs. Despite their absence, photoreceptors maintained a normal rate of OS assembly. In contrast, photoreceptors displayed a reduced distal displacement of LY-labeled membranes in eyecups treated with cytochalasin D, showing that our technique can detect drug-induced changes in basal rod outer segment assembly. The reduction noted in the cytochalasin-treated cells was due to the abnormal lateral displacement of newly added OS disc membranes that occurs with this drug (Williams, D. S., K. A. Linberg, D. K. Vaughan, R. N. Fariss, and S. K. Fisher. 1988. J. Comp. Neurol. 272:161-176). Together, our results indicate that the vectorial transport of OS membrane constituents through the ellipsoid and their assembly into OS disc membranes are not dependent on elliposid MT integrity.

Gross motor skills of South African preschool-aged children across different income settings.

OBJECTIVES: No studies have investigated gross motor skill (GMS) proficiency of preschool-aged children across different income settings in South Africa. Research from high-income countries suggests that children from low-income settings display poorer GMS proficiency compared to higher-income peers. This study aimed to (1) describe GMS proficiency of preschool-aged children in urban high-income (UH), urban low-income (UL) and rural low-income (RL) settings; and (2) explore differences in proficiency between income settings and sex. DESIGN: Descriptive cross-sectional study. METHODS: The Test of Gross Motor Development-Edition 2 (TGMD-2) was used to assess GMS. The TGMD-2 gross motor quotient, standardised scores and raw scores were used to describe proficiency. RESULTS: GMS proficiency was assessed in n=259 3-6-year-old children (n=46 UH, n=91 UL, n=122 RL). Overall, 93% of the children were classified as having 'average' or better GMS. According to TGMD-2 standardised scores, the RL children performed significantly better than UH and UL children (p=0.028 and p=0.009, respectively). RL children were significantly more proficient than UH and UL children in the strike and horizontal jump when comparing raw scores. Overall, boys performed significantly better than girls in the strike, stationary dribble, kick and leap when comparing raw scores (all p<0.001). CONCLUSIONS: This study reports high GMS proficiency in preschool-aged children across income settings in South Africa. The factors associated with higher GMS in low-income settings are not immediately obvious. Thus, future research should explore potential factors and identify opportunities to ensure that GMS proficiency is capitalised on as preschool-aged children enter formal schooling.

Bortezomib and gemcitabine in relapsed or refractory Hodgkin's lymphoma.

BACKGROUND: Given the significant activity and tolerability of gemcitabine in patients with relapsed Hodgkin's lymphoma (HL), the critical role that nuclear factor kappa B (NF-kappaB) appears to play in the pathogenesis of this tumor, the ability of bortezomib to inhibit NF-kappaB activity, and laboratory studies suggesting synergistic antitumor effects of gemcitabine and bortezomib, we hypothesized that this combination would be efficacious in patients with relapsed or refractory HL. PATIENTS AND METHODS: A total of 18 patients participated. Patients received 3-week cycles of bortezomib 1 mg/m(2) on days 1, 4, 8, and 11 plus gemcitabine 800 mg/m(2) on days 1 and 8. RESULTS: The overall response rate for all patients was 22% (95% confidence interval 3% to 42%). Three patients developed grade III transaminase elevation: one was removed from the study and two had doses of gemcitabine held. Almost all patients exhibited inhibition of proteasome activity with treatment. CONCLUSIONS: The combination of gemcitabine and bortezomib is a less active and more toxic regimen in relapsed HL than other currently available treatments. It poses a risk of severe liver toxicity and should be pursued with caution in other types of cancer.

Studies on the pathogenesis of pigment gallstones in hemolytic anemia: description and characteristics of a mouse model.

The pathogenesis of hemolysis-induced gallstones was studied in mice with a hereditary hemolytic disease called normoblastic anemia (genotype nb/nb) and in their normal controls (genotype +/+). Infrared spectroscopy demonstrated that spontaneously formed gallstones from nb/nb mice were nearly identical to stones from patients with chronic hemolysis as the result of sickle cell disease, and both mouse and human stones strikingly resembled synthetic calcium bilirubinate. 57% of 115 nb/nb mice, but none of 109 control mice, developed calcium bilirubinate pigment gallstones (P < 0.001). The incidence of luminal gallstones in nb/nb mice was both sex and age dependent. Female nb/nb mice formed stones twice as frequently as male nb/nb mice (P < 0.001). Before 6 mo of age neither sex developed stones, but thereafter the incidence of stones increased with age. Neither hematocrit, reticulocyte count, nor total plasma bilirubin values, were useful in distinguishing between nb/nb mice with or without gallstones. In gallbladder bile, nb/nb mice with gallstones had higher concentrations of hydrogen ion, total bilirubin, calcium, and bile acids than nb/nb mice without stones. Although total unconjugated bilirubin was similar in both nb/nb groups, the ionized fraction of unconjugated bilirubin was higher in bile from nb/nb mice without stones than those with stones. In nb/nb mice, neutral mucin plugs and pigment concentrations were observed histologically in the glandular crypts of the gallbladder in 33% of nb/nb mice without stones and in 80% of nb/nb mice with luminal stones. This suggested that luminal pigment stone disease in mice with hemolysis may be preceded by microscopic precipitation of calcium bilirubinate in the glandular crypts of the gallbladder. These precipitates may then migrate into the lumen and grow by accretion.

Expression of the early growth response 1 and 2 zinc finger genes during induction of monocytic differentiation.

Members of the early growth response (EGR) gene family are rapidly induced after mitogenic stimulation of diverse cell types. The present work has examined EGR gene expression during differentiation of myeloid leukemia cells along the monocytic lineage and in activated monocytes. Low levels of EGR-1 transcripts were detectable in untreated U-937 and HL-60 leukemia cells. In contrast, treatment of these cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) was associated with increases (within 1 h) in EGR-1 mRNA levels. The induction of monocytic differentiation by TPA and other agents was further associated with increases in EGR-2, but not EGR-3 or EGR-4, mRNA levels in these cells. Treatment of resting peripheral blood monocytes with the macrophage colony-stimulating factor (M-CSF) was also associated with rapid (within 15 min) increases in expression of the EGR-1 and EGR-2 genes. The results of nuclear run-on assays demonstrate that EGR-1 mRNA levels are increased in part by transcriptional activation of this gene in M-CSF-stimulated monocytes. The results also demonstrate that both EGR-1 and EGR-2 mRNA levels are regulated at the posttranscriptional level by a labile protein that destabilizes these transcripts. Finally, we demonstrate that dexamethasone, an inhibitor of monocytic differentiation, blocks the associated increases in EGR-1 and EGR-2 expression. Taken together, the results indicate that the EGR-1 and EGR-2 early response genes are involved in the induction of myeloid leukemia cell differentiation along the monocytic lineage and in the activation of human monocytes.

Alternative RNA splicing generates transcripts encoding a thorax-specific isoform of Drosophila melanogaster myosin heavy chain.

Genomic and cDNA sequencing studies show that transcripts from the muscle myosin heavy-chain (MHC) gene of Drosophila melanogaster are alternatively spliced, producing RNAs that encode at least two MHC isoforms with different C termini. Transcripts encoding an MHC isoform with 27 unique C-terminal amino acids accumulate during both larval and adult muscle differentiation. Transcripts for the second isoform encode one unique C-terminal amino acid and accumulate almost exclusively in pupal and adult thoracic segments, the location of the indirect flight muscles. The 3' splice acceptor site preceding the thorax-specific exon is unusually purine rich and thus may serve as a thorax-specific splicing signal. We suggest that the alternative C termini of these two MHC isoforms control myofilament assembly and may play a role in generating the distinctive myofilament organizations of flight muscle and other muscle types.

The Michigan Risk Score to predict peripherally inserted central catheter-associated thrombosis.

Essentials How best to quantify thrombosis risk with peripherally inserted central catheters (PICC) is unknown. Data from a registry were used to develop the Michigan Risk Score (MRS) for PICC thrombosis. Five risk factors were associated with PICC thrombosis and used to develop a risk score. MRS was predictive of the risk of PICC thrombosis and can be useful in clinical practice. SUMMARY: Background Peripherally inserted central catheters (PICCs) are associated with upper extremity deep vein thrombosis (DVT). We developed a score to predict risk of PICC-related thrombosis. Methods Using data from the Michigan Hospital Medicine Safety Consortium, image-confirmed upper-extremity DVT cases were identified. A logistic, mixed-effects model with hospital-specific random intercepts was used to identify factors associated with PICC-DVT. Points were assigned to each predictor, stratifying patients into four classes of risk. Internal validation was performed by bootstrapping with assessment of calibration and discrimination of the model. Results Of 23 010 patients who received PICCs, 475 (2.1%) developed symptomatic PICC-DVT. Risk factors associated with PICC-DVT included: history of DVT; multi-lumen PICC; active cancer; presence of another CVC when the PICC was placed; and white blood cell count greater than 12 000. Four risk classes were created based on thrombosis risk. Thrombosis rates were 0.9% for class I, 1.6% for class II, 2.7% for class III and 4.7% for class IV, with marginal predicted probabilities of 0.9% (0.7, 1.2), 1.5% (1.2, 1.9), 2.6% (2.2, 3.0) and 4.5% (3.7, 5.4) for classes I, II, III, and IV, respectively. The risk classification rule was strongly associated with PICC-DVT, with odds ratios of 1.68 (95% CI, 1.19, 2.37), 2.90 (95% CI, 2.09, 4.01) and 5.20 (95% CI, 3.65, 7.42) for risk classes II, III and IV vs. risk class I, respectively. Conclusion The Michigan PICC-DVT Risk Score offers a novel way to estimate risk of DVT associated with PICCs and can help inform appropriateness of PICC insertion.

Rituximab in combination with fludarabine chemotherapy in low-grade or follicular lymphoma.

PURPOSE: To evaluate the safety and efficacy of fludarabine plus rituximab in treatment-naive or relapsed patients with low-grade and/or follicular non-Hodgkin's lymphoma. PATIENTS AND METHODS: This was an open-label, single-arm, single-center phase II study enrolling 40 patients. During the first week of the study, patients received two infusions of rituximab 375 mg/m2 administered 4 days apart. Seventy-two hours after the second infusion of rituximab, patients received the first of six cycles of fludarabine chemotherapy (25 mg/m2/d for 5 days on a 28-day cycle). Single infusions of rituximab were administered 72 hours before the second, fourth, and sixth cycles of fludarabine, and two infusions of rituximab were given 4 weeks after the last cycle of fludarabine. Treatment duration was 26 weeks. RESULTS: An overall response rate of 90% (80% complete response rate) was achieved in the intent-to-treat population. Similar response rates were seen in treatment-naive and previously treated patients. The median duration of response has not been reached at 40+ months. The median follow-up time in this study is 44 months (range, 15 to 66 months). In patients positive for the 14;18 translocation in blood and/or marrow at enrollment, molecular remission was achieved in 88% of cases, with patients remaining negative for up to 4 years to date. Hematologic toxicity was manageable, and except for a 15% incidence of herpes simplex/zoster infections, infectious complications were rare. Nonhematologic toxicities were minimal. CONCLUSION: Rituximab plus fludarabine was well tolerated and associated with an excellent complete response rate, including molecular remissions, in patients with low-grade or follicular lymphoma.