Adverse health outcomes and health concerns among survivors of various childhood cancers: Perspectives from mothers.

Advanced therapies have improved outcomes and also resulted in a growing risk of long-term adverse health events. This study intends to estimate incidences of adverse health events and examine differences in adverse health events among childhood cancer survivors, and to understand the concerns of mothers after their child has completed cancer treatment. An explanatory sequential mixed-method was used. A total of 201 paediatric cancer survivors' mothers with mean age 43.6 years were recruited. Of the survivors, 12.4% experienced five or more adverse health events. The incidence of adverse health events of altered body image, fatigue and neurocognitive problems were 31.54%, 14.77% and 12.53% respectively. Among survivors, significant differences in adverse health events of pain, endocrine problems and altered body image issues were identified. Survivors receiving radiotherapy, bone marrow transplants or completing treatment after 6-10 years experienced significantly more adverse health events. Maintaining health was the greatest concern for mothers, and the qualitative reports of their concerns could be categorised: living in uncertainty, and keeping forward-looking. Childhood brain tumour survivors were identified as experiencing more adverse health events than other survivors. The need for healthcare teams to consider mothers' health concerns was highlighted.

Relationships between the integrity and function of lumbar nerve roots as assessed by diffusion tensor imaging and neurophysiology.

PURPOSE: Diffusion tensor imaging (DTI) has shown promise in the measurement of peripheral nerve integrity, although the optimal way to apply the technique for the study of lumbar spinal nerves is unclear. The aims of this study are to use an improved DTI acquisition to investigate lumbar nerve root integrity and correlate this with functional measures using neurophysiology. METHODS: Twenty healthy volunteers underwent 3 T DTI of the L5/S1 area. Regions of interest were applied to L5 and S1 nerve roots, and DTI metrics (fractional anisotropy, mean, axial and radial diffusivity) were derived. Neurophysiological measures were obtained from muscles innervated by L5/S1 nerves; these included the slope of motor-evoked potential input-output curves, F-wave latency, maximal motor response, and central and peripheral motor conduction times. RESULTS: DTI metrics were similar between the left and right sides and between vertebral levels. Conversely, significant differences in DTI measures were seen along the course of the nerves. Regression analyses revealed that DTI metrics of the L5 nerve correlated with neurophysiological measures from the muscle innervated by it. CONCLUSION: The current findings suggest that DTI has the potential to be used for assessing lumbar spinal nerve integrity and that parameters derived from DTI provide quantitative information which reflects their function.

Body mass index and breast cancer: analysis of a nation-wide population-based prospective cohort study on 1 393 985 Taiwanese women.

BACKGROUND: Asian women have a younger age at onset of breast cancer and a lower body mass index (BMI) than Western women. The link between obesity and risk of breast cancer in Asian women is still elusive. We aimed to investigate the effect of BMI on the risk of incident breast cancer in Taiwanese women. METHODS: A total of 1,393,985 women who had been cancer-free before recruitment and attended a nation-wide Taiwanese breast cancer-screening program between 1999 and 2009 were enrolled using a prospective cohort study. Obesity and other relevant variables (such as menopause status and other biochemical markers) were collected through in-person interviews, anthropometric measurements and blood samples at first screen. Incident breast cancers during follow-up were ascertained through the linkage of the cohort with the National Cancer Registry and the National Death Certification System. RESULTS: A total of 6969 and 7039 incident breast cancer cases were identified among women enrolled before and after menopause, respectively. Compared with a BMI range of 18.5-23.9 kg m(-)(2), the incremental level of BMI in the enrolled women before menopause revealed a lack of statistically significant association with the risk of incident breast cancer (adjusted hazard ratio=0.94, 0.98, 1.02, 1.01 and 0.82 for BMI <18.5, 24-26.9, 27-29.9, 30-34.9 and ⩾35, respectively), but the incremental level of BMI in the enrolled women after menopause led to a statistically significant incremental increase in the risk of breast cancer (adjusted hazard ratio=0.78, 1.19, 1.31, 1.53 and 1.65 for BMI <18.5, 24-26.9, 27-29.9, 30-34.9 and ⩾35, respectively) after adjusting for other explanatory risk factors. CONCLUSION: Obesity acts mainly as an influential promoter of the development of late-onset breast cancer after menopause in Taiwanese women.

Rank-based estimating equations with general weight for accelerated failure time models: an induced smoothing approach.

The induced smoothing technique overcomes the difficulties caused by the non-smoothness in rank-based estimating functions for accelerated failure time models, but it is only natural when the estimating function has Gehan's weight. For a general weight, the induced smoothing method does not provide smooth estimating functions that can be easily evaluated. We propose an iterative-induced smoothing procedure for general weights with the estimator from Gehan's weight initial value. The resulting estimators have the same asymptotic properties as those from the non-smooth estimating equations with the same weight. Their variances are estimated with an efficient resampling approach that avoids solving estimating equations repeatedly. The methodology is generalized to incorporate an additional weight to accommodate missing data and various sampling schemes. In a numerical study, the proposed estimators were obtained much faster without losing accuracy in comparison to those from non-smooth estimating equations, and the variance estimators provided good approximation of the variation in estimation. The methodology was applied to two real datasets, the first one from an adolescent depression study and the second one from a cancer study with missing covariates by design. The implementation is available in an R package aftgee.

Risk factors influencing the outcome of peptic ulcer bleeding in end stage renal diseases after initial endoscopic haemostasis.

Background and Aims: Patients suffering from peptic ulcer (PU) bleeding who have end-stage renal disease (ESRD) may encounter more adverse outcomes. The primary objective is to investigate the risk factors that influence the outcomes of ESRD and chronic kidney disease (CKD) patients with PU bleeding after successful initial endoscopic haemostasis. Methods: A total of 540 patients with PU bleeding after initial endoscopic haemostasis in a tertiary hospital were investigated retrospectively. They were sorted into three groups after randomised age-matched adjustment: ESRD group (n = 90), CKD group (n = 90) and control group (n = 360). Main outcome measurements were rebleeding, requirement for blood transfusion and surgery, length of hospital stay and mortality. Results: The rebleeding rates were 43% for the ESRD group vs. 21% for the CKD group vs. 12% for the control group (overall p = < 0.001). Multivariate analysis showed the predictors of rebleeding were ESRD, time to endoscope, and non-high-dose proton-pump inhibitors (PPI) users. The risk factors for bleeding-related mortality were presence of moderate degree of CKD and ESRD group, time to endoscope, and Rockall score. All-cause mortality was related to presence of moderate degree of CKD and ESRD group, platelet count, time to endoscope, Rockall score and length of hospital stay. Conclusions: ESRD patients who suffered from PU bleeding were at risk of excessive rebleeding and mortality with frequent occurrence of delayed rebleeding. This study suggests that early endoscopy for initial haemostasis and high-dose intravenous PPI are associated with the reduction of rebleeding risk especially in patients with high Rockall scores.

Reliability of high-density surface electromyography for assessing characteristics of the thoracic erector spinae during static and dynamic tasks.

PURPOSE: To establish intra- and inter-session reliability of high-density surface electromyography (HDEMG)-derived parameters from the thoracic erector spinae (ES) during static and dynamic goal-directed voluntary movements of the trunk, and during functional reaching tasks. METHODS: Twenty participants performed: 1) static trunk extension, 2) dynamic trunk forward and lateral flexion, and 3) multidirectional functional reaching tasks on two occasions separated by 7.5 ± 1.2 days. Muscle activity was recorded bilaterally from the thoracic ES. Root mean square (RMS), coordinates of the barycentre, mean frequency (MNF), and entropy were derived from the HDEMG signals. Reliability was determined with intraclass correlation coefficient (ICC), coefficient of variation, and standard error of measurement. RESULTS: Good-to-excellent intra-session reliability was found for all parameters and tasks (ICC: 0.79-0.99), whereas inter-session reliability varied across tasks. Static tasks demonstrated higher reliability in most parameters compared to functional and dynamic tasks. Absolute RMS and MNF showed the highest overall reliability across tasks (ICC: 0.66-0.98), while reliability of the barycentre was influenced by the direction of the movements. CONCLUSION: RMS and MNF derived from HDEMG show consistent inter-session reliability in goal-directed voluntary movements of the trunk and reaching tasks, whereas the measures of the barycentre and entropy demonstrate task-dependent reliability.

Efflux transporters in rat placenta and developing brain: transcriptomic and functional response to paracetamol.

Adenosine triphosphate binding cassette (ABC) transporters transfer lipid-soluble molecules across cellular interfaces either directly or after enzymatic metabolism. RNAseq analysis identified transcripts for ABC transporters and enzymes in rat E19, P5 and adult brain and choroid plexus and E19 placenta. Their functional capacity to efflux small molecules was studied by quantitative analysis of paracetamol (acetaminophen) and its metabolites using liquid scintillation counting, autoradiography and ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). Animals were treated acutely (30 min) and chronically (5 days, twice daily) with paracetamol (15 mg/kg) to investigate ability of brain and placenta barriers to regulate ABC transport functionality during extended treatment. Results indicated that transcripts of many efflux-associated ABC transporters were higher in adult brain and choroid plexus than at earlier ages. Chronic treatment upregulated certain transcripts only in adult brain and altered concentrations of paracetamol metabolites in circulation of pregnant dams. Combination of changes to metabolites and transport system transcripts may explain observed changes in paracetamol entry into adult and fetal brains. Analysis of lower paracetamol dosing (3.75 mg/kg) indicated dose-dependent changes in paracetamol metabolism. Transcripts of ABC transporters and enzymes at key barriers responsible for molecular transport into the developing brain showed alterations in paracetamol pharmacokinetics in pregnancy following different treatment regimens.

The reproducibility of the virtual organ computer-aided analysis program for evaluating 3-dimensional power Doppler ultrasonography of diffuse thyroid disorders.

AIM: The aim of this study was to evaluate the intra- observer and inter-observer reproducibility of 3-dimensional (3D) power Doppler ultrasonography with the virtual organ computer-aided analysis (VOCAL) program for measuring thyroid volume and vascular indices in patients with diffuse thyroid disorders. MATERIALS AND METHODS: Patients with diffuse goiters were examined by 3D ultrasonography from August 2005 to July 2006. The parameters for vascular assessment included the vascularization index (VI), flow index (FI), vascularization-flow index (VFI), and thyroid size, and were obtained using the VOCAL program. This program used plane A and a 30 degrees rotational step. Intra-observer and inter-observer repeatability are presented as intra-class correlation coefficient (intra-CC) and inter-class correlation coefficient (inter-CC), with values >0.70 being acceptable. RESULTS: Sixty-three patients in total were enrolled for this study, including 19 patients with simple goiter and 44 patients with autoimmune thyroid disease (AITD) (23 Graves' disease, 21 Hashimoto's thyroiditis). Thyroid volume and 3 vascular indices showed excellent reproducibility in the AITD group (intra- CC>0.9373 and inter-CC>0.8763) and its subgroups. The VI had excellent consistent reproducibility in the simple goiter group (intra-CC>0.8987 and inter-CC>0.8881), but the other parameters did not. CONCLUSIONS: Based on this study, 3D power Doppler ultrasonography with the VOCAL program is a reliable tool for evaluating diffuse thyroid disorders due to an autoimmune process. The VI is the most reliable parameter.

Nonidentifiability in the presence of factorization for truncated data.

A time to event, [Formula: see text], is left-truncated by [Formula: see text] if [Formula: see text] can be observed only if [Formula: see text]. This often results in oversampling of large values of [Formula: see text], and necessitates adjustment of estimation procedures to avoid bias. Simple risk-set adjustments can be made to standard risk-set-based estimators to accommodate left truncation when [Formula: see text] and [Formula: see text] are quasi-independent. We derive a weaker factorization condition for the conditional distribution of [Formula: see text] given [Formula: see text] in the observable region that permits risk-set adjustment for estimation of the distribution of [Formula: see text], but not of the distribution of [Formula: see text]. Quasi-independence results when the analogous factorization condition for [Formula: see text] given [Formula: see text] holds also, in which case the distributions of [Formula: see text] and [Formula: see text] are easily estimated. While we can test for factorization, if the test does not reject, we cannot identify which factorization condition holds, or whether quasi-independence holds. Hence we require an unverifiable assumption in order to estimate the distribution of [Formula: see text] or [Formula: see text] based on truncated data. This contrasts with the common understanding that truncation is different from censoring in requiring no unverifiable assumptions for estimation. We illustrate these concepts through a simulation of left-truncated and right-censored data.

Overexpression of NBS1 induces epithelial-mesenchymal transition and co-expression of NBS1 and Snail predicts metastasis of head and neck cancer.

Major causes of head and neck squamous cell carcinoma (HNSCC)-related deaths are cervical node and distant metastasis. We previously demonstrated that overexpression of the DNA double-strand break repair protein Nijmegen breakage syndrome 1 (NBS1) is a prognostic marker of advanced HNSCCs. Epithelial-mesenchymal transition (EMT) was demonstrated to be the major mechanism responsible for mediating invasiveness and metastasis of late-stage cancers. We therefore investigated the role of NBS1 overexpression in mediating EMT and metastasis. NBS1 overexpression was associated with metastasis of HNSCC patients using tissue microarray-immunohistochemistry approach. Induction of EMT was observed in an NBS1-overexpressing HNSCC cell line (FADUNBS), whereas short-interference RNA (siRNA)-mediated repression of endogenous NBS1 reversed the shift of EMT markers. Increased migration/invasiveness of FADUNBS was shown by in vitro and in vivo assays. NBS1 overexpression upregulated the expression of an EMT regulator Snail and its downstream target matrix metalloproteinase-2. EMT phenotypes and increased migration/invasiveness of FADUNBS cells were reversed by siRNA-mediated repression of Snail expression or a phosphatidylinositol 3-kinase-specific inhibitor. In HNSCC samples, co-expression of NBS1/Snail in primary tumors correlated with metastasis and the worst prognosis. These results indicate that NBS1 overexpression induces EMT through the upregulation of Snail expression, and co-expression of NBS1/Snail predicts metastasis in HNSCCs.

Overexpression of beta2-microglobulin is associated with poor survival in patients with oral cavity squamous cell carcinoma and contributes to oral cancer cell migration and invasion.

beta2-Microglobulin (beta2M), a component of MHC class I molecules, is believed to be associated with tumour status in various cancers. In this study, we examined the expression of beta2M at different malignant stages of oral cavity squamous cell carcinoma (OCSCC). To determine the possible correlation between beta2M expression and various clinical characteristics, 256 samples from patients with OCSCC were evaluated by immunohistochemical staining. Strong beta2M expression was significantly correlated with a relatively advanced tumour stage (P<0.001), positive nodal status (P<0.001), and TNM stage (P<0.001). The cumulative 5-year survival rate was significantly correlated with a relatively advanced tumour stage (P<0.001), positive nodal status (P<0.001), TNM stage (P<0.001), and strong expression of beta2M (P<0.001). Thus, elevated beta2M expression is an indicator of poor survival (P<0.001). In addition, we extended our analysis of beta2M expression to the FaDu and SCC25 oral cancer cell lines. beta2-Microglobulin expression was positively correlated with cell migration and invasion in beta2M-overexpressing transfectants in Transwell chambers. The suppression of beta2M expression using small interfering RNA (siRNA) was sufficient to decrease cell migration and invasion in vitro. Taken together, our results suggest that beta2M expression in the tissues is associated with survival and may be involved in tumour progression and metastasis in OCSCC.

Isolation and characterization of mesenchymal stromal cells from human anterior cruciate ligament.

BACKGROUND: The anterior cruciate ligament (ACL) is one of the most commonly injured ligaments of the knee. Because the torn ACL is always discarded during ACL reconstruction, it may be a potential source for isolating mesenchymal stromal cells (MSC). METHODS: To characterize MSC from human ACL, cells were enzymatically released from the ACL of adult human donors and seeded in plastic dishes with serial passages at confluence. At different passages, ACL-derived cells were subjected to in vitro assays to investigate their multilineage potential. Upon treatment, the phenotypes of the cell cultures were analyzed by histo- and immunohistochemistry and semi-quantitative reverse transcription-polymerase chain reaction for the expression of lineage-specific genes. RESULTS: Six independent cell lines from individual donors showed diversity in multilineage potential. Interestingly, five of the six lines displayed adipogenic potential, four had osteogenic and adipogenic potential, and only one cell line was tripotent. Both bone marrow (BM)- and ACL-derived MSC expressed marker genes for ligament fibroblasts, whereas the mRNA levels of collagen I and III were more abundant in ACL-derived MSC. DISCUSSION: Our study demonstrates that human MSC can be isolated from ACL with diversity in the potential to form bone, fat and cartilage and an increase as compared to BM MSC, in the potential to form ligament fibroblasts.

Effect of chewing a single betel-quid on autonomic nervous modulation in healthy young adults.

Betel-quid is widely used around the world as a stimulant for the autonomic nervous system. The aim of this study was to assess the effect of betel-quid chewing on autonomic nervous modulation by using spectral heart rate variability (HRV) analysis. Twenty healthy young adults were included in this study. Each subject chewed a single betel-quid containing one betel nut or a piece of chewing-gum for 60 min on different days in random order. Spectral HRV measures were obtained before, and 5, 30 and 60 min after starting to chew betel-quid or gum. Sequential changes in HRV measures were compared between chewing gum and betel-quid. Heart rate was significantly elevated after 5 min chewing betel-quid, but not after chewing gum. The normalized low-frequency power and low-/high-frequency power ratio were elevated after 5 min chewing gum or betel-quid; however, the normalized high-frequency power was reduced after 5 min chewing gum or betel-quid. The percentage changes in total power after 5, 30 and 60 min chewing betel-quid were significantly lower than those after chewing gum. This study confirms that novice chewing of betel-quid modulates autonomic nervous system activity; transiently enhancing sympathetic activity and gradually suppressing vagal activity in healthy young adults.

Benzene-di-N-substituted carbamates as conformationally constrained substrate analogs of cholesterol esterase.

Benzene-1,2-, 1,3-, and 1,4-di-N-substituted carbamates (1-15) are synthesized as the constrained analogs of gauche, eclipsed, and anti conformations, respectively, for the glycerol backbones of triacylglycerol. Carbamates 1-15 are characterized as the pseudo substrate inhibitors of cholesterol esterase. Long chain carbamates are more potent inhibitors than short chain ones. Comparison of different geometries for benzene-di-substituted carbamates, such as benzene-1,2-di-N-octylcarbamate (3) (ortho-3), benzene-1,3-di-N-octylcarbamate (8) (meta-8), and benzene-1,4-di-N-octylcarbamates (13) (para-13), indicates that inhibitory potencies are as followed: meta-8 > para-13 > ortho-3. Therefore, we suggest that the preferable conformation for the C(sn-1)-O/C(sn-2)-O glycerol backbone in the enzyme-triacylgycerol complex is the eclipsed conformation. Meanwhile, kinetic data indicate that among ortho, meta, and para carbamates, meta carbamates most resemble the substrate cholesterol ester.

Characterization of a novel thermophilic, cellulose-degrading bacterium Paenibacillus sp. strain B39.

AIMS: The aims of this study were to identify and characterize the novel thermophilic, cellulose-degrading bacterium Paenibacillus sp. strain B39. METHODS AND RESULTS: Strain B39 was closely related to Paenibacillus cookii in 16S rRNA gene sequence. Nonetheless, this isolate can be identified as a novel Paenibacillus sp. with respect to its physiological characteristics, biochemical reactions, and profiles of fatty acid compositions. A cellulase with both CMCase and avicelase activities was secreted from strain B39 and purified by ion-exchange chromatography. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, the molecular weight of B39 cellulase was determined as 148 kDa, which was much higher than other cellulases currently reported from Paenibacillus species. The enzyme showed a maximum CMCase activity at 60 degrees C and pH 6.5. Addition of 1 mmol l(-1) of Ca(2+) markedly enhanced both CMCase and avicelase activities of the enzyme. CONCLUSIONS: We have identified and characterized a novel thermophilic Paenibacillus sp. strain B39 which produced a high-molecular weight cellulase with both CMCase and avicelase activities. SIGNIFICANCE AND IMPACT OF THE STUDY: Based on the ability to hydrolyse CMC and avicel, the cellulase produced by Paenibacillus sp. strain B39 would have potential applications in cellulose biodegradation.

Evaluation of cortical perfusion in renal transplants: application of quantified power Doppler ultrasonography.

Perfusion of renal transplants may be altered by various pathological conditions. This study assessed cortical perfusion of renal transplants during acute rejection episodes using power Doppler quantification. Forty-eight renal transplant patients with clinical indications for biopsy were included in this study. Power Doppler ultrasonography (US) of these renal transplants was performed prior to biopsy. Power Doppler image intensity in the proximal outer cortex of renal transplants was quantified by image analysis software. The results of power Doppler quantification were compared with the clinical data and histological findings. Biopsies were classified into three groups based on Banff diagnostic categories: group 1 (no acute rejection; 26 patients), group 2 (acute cell-mediated rejection alone; 12 patients), and group 3 (acute antibody-mediated rejection with/or without acute cell-mediated rejection; 10 patients). The power Doppler intensity of the outer renal cortex was 1.98 +/- 1.50 dB for group 1, 1.38 +/- 0.86 dB for group 2, and 0.81 +/- 0.66 dB for group 3. Statistically, there was a significant difference between group 1 and group 3 (1.98 vs 0.81 dB, P = .01) but not between group 1 and group 2 (1.98 vs 1.38 dB, P = .34). In conclusion, the status of cortical perfusion of renal transplants can be determined noninvasively by quantified power Doppler US. Accordingly, acute antibody-mediated rejection is associated with significantly decreased cortical perfusion, which, we propose, is due to this distinct pathological process.

Transcripts of enriched germ cells responding to heat shock as potential markers for porcine semen quality.

A cDNA microarray-assisted experiment was conducted to survey genes that respond early to heat shock in enriched immature porcine germ cells; the 5'-UTR flanking the highest upregulated gene, heat shock 105/110 kDa protein 1 (Hsph1 or Hsp105), in response to heat shock was also investigated. We established a porcine testis cDNA microarray with 9944 transcripts from two libraries constructed from the testes of mature boars, with or without heat shock. After a mild heat shock treatment (39 degrees C for 1h and recovered at 34 degrees C for 2h), 380 transcripts demonstrated significant gene expression in enriched immature germ cells; 326 were upregulated and 54 were downregulated. Ten transcripts of interest exhibiting significance analysis of microarrays (SAM) scores higher than the median were subjected to quantitative real-time PCR; three (Hsp105, Hspa4l and Thap4) were upregulated >1.5-fold. The sequence of the 5'-UTR of Hsp105, the highest upregulated transcript, was cloned and analyzed. A single nucleotide polymorphism (SNP) was found at position -762 (C or T) upstream of the translational start site (ATG codon). Only two genotypes (CC or TC) were found in the mature boars that were studied (n=31). A heterozygous genotype (TC) at this SNP site revealed an elevated percentage of morphologically normal sperm during hot and cold seasons; this SNP may be a useful marker for semen quality in boars. Furthermore, the cell-model established from enriched primitive germ cells has potential for the study of reproduction in mature animals.

Endothelin binding to cultured calf adrenal zona glomerulosa cells and stimulation of aldosterone secretion.

Endothelins are a group of potent vasoconstrictors whose structure was deduced from genomic DNA. ET-1 was first isolated from culture supernatants from porcine endothelial cells and ET-3 was identified from a rat DNA library. We report on the binding of 125I-ET-1 to zona glomerulosa cells in culture and on its ability to stimulate aldosterone secretion. Cultured calf adrenal zona glomerulosa cells have saturable, high affinity [Kd = 1.00 +/- 0.17 X 10(-10) M (SEM)] receptors which bind ET-1 in a temperature and time dependent manner. Binding was specific and angiotensin II, vasopressin, ANP, BNP, apamin, calcium channel agonists or antagonists did not interact with the receptor. ET-3 displaced 125I-ET-1 from the receptor with a relative potency of 0.39 +/- 0.1% (SEM) that of ET-1. ET-1 incubated with cultured glomerulosa cells stimulated aldosterone secretion in a dose dependent manner but it was less potent than angiotensin II. ET-3 had less than 1% the relative potency of ET-1 stimulating aldosterone secretion. This data suggest that ET-1 is an independent stimulator of aldosterone secretion and we are speculating that it might be important in those situations, like in malignant hypertension, where endothelial damage might result in increased ET-1 production.

Molecular basis of spectrin deficiency in beta spectrin Durham. A deletion within beta spectrin adjacent to the ankyrin-binding site precludes spectrin attachment to the membrane in hereditary spherocytosis.

We describe a spectrin variant characterized by a truncated beta chain and associated with hereditary spherocytosis. The clinical phenotype consists of a moderate hemolytic anemia with striking spherocytosis and mild spiculation of the red cells. We describe the biochemical characteristics of this truncated protein which constitutes only 10% of the total beta spectrin present on the membrane, resulting in spectrin deficiency. Analysis of reticulocyte cDNA revealed the deletion of exons 22 and 23. We show, using Southern blot analysis, that this truncation results from a 4.6-kb genomic deletion. To elucidate the basis for the decreased amount of the truncated protein on the membrane and the overall spectrin deficiency, we show that (a) the mutated gene is efficiently transcribed and its mRNA abundant in reticulocytes, (b) the mutant protein is normally synthesized in erythroid progenitor cells, (c) the stability of the mutant protein in the cytoplasm of erythroblasts parallels that of the normal beta spectrin, and (d) the abnormal protein is inefficiently incorporated into the membrane of erythroblasts. We conclude that the truncation within the beta spectrin leads to inefficient incorporation of the mutant protein into the skeleton despite its normal synthesis and stability. We postulate that this misincorporation results from conformational changes of the beta spectrin subunit affecting the binding of the abnormal heterodimer to ankyrin, and we provide evidence based on binding assays of recombinant synthetic peptides to inside-out-vesicles to support this model.