Mutation of the receptor tyrosine kinase gene Mertk in the retinal dystrophic RCS rat

Vertebrate photoreceptor cells are the basic sensory apparatus of the retina, capable of converting the energy of absorbed photons into neuronal signals. The proximal portions of mammalian photoreceptor outer segments are synthesized daily by cell bodies, and outer segment tips are shed with a circadian rhythm, resulting in a complete turnover of outer segments about every 9 days. The shed outer segments are phagocytosed by adjacent retinal pigment epithelial (RPE) cells, and metabolites are recycled to photoreceptors. The Royal College of Surgeons (RCS) rat is a widely studied, classic model of recessively inherited retinal degeneration in which the RPE fails to phagocytose shed outer segments, and photoreceptor cells subsequently die. We have used a positional cloning approach to study the rdy (retinal dystrophy) locus of the RCS rat. Within a 0.3 cM genetic inclusion interval, we have discovered a small deletion of RCS DNA that disrupts the gene encoding the receptor tyrosine kinase Mertk. The deletion includes the splice acceptor site upstream of the second coding exon of Mertk and results in a shortened transcript that lacks this exon. The aberrant transcript joins the first and third coding exons, leading to a frameshift and a translation termination signal 20 codons after the AUG. The concordance of these and other data indicate that Mertk is probably the gene for rdy. Our results provide genetic evidence for an essential role of a receptor tyrosine kinase in a specialized form of phagocytosis and suggest a molecular model for ingestion of outer segments by RPE cells.

Strength and cross-sectional area of human skeletal muscle

The maximum voluntary force (strength) which could be produced by the knee-extensor muscles, with the knee held at a right angle, was measured in a group of healthy young subjects comprising twenty-five males and twenty-five females. Both legs were tested: data from the stronger leg only for each subject were used in the present study. Computed tomography was used to obtain a cross-sectional image of the subjects' legs at mid-thigh level, measured as the mid-point between the greater trochanter and upper border of the patella. The cross-sectional area of the knee-extensor muscles was determined from the image obtained by computer-based planimetry. The subjects' height and weight were measured. An estimate of body fat content was obtained from measurements of skinfold thicknesses and used to calculate lean body mass. Male subjects were taller (P less than 0.001), heavier (P less than 0.001), leaner (P less than 0.001) and stronger (P less than 0.001) than the female subjects. No significant correlation was found to exist between strength of the knee-extensor muscles and body weight in the male or in the female subjects. In the male subjects, but not in the female group, there was a positive correlation (r = 0.50; P less than 0.01) between strength and lean body mass. Muscle cross-sectional area of the male subjects was greater than that of the female subjects (P less than 0.001). The ratio of strength to cross-sectional area for the male was 9.49 +/- 1.34 (mean +/- S.D.). This is greater but not significantly so, than that for females (8.92 +/- 1.11). In both male and female groups, there was a significant (P less than 0.01) positive correlation between muscle strength and cross-sectional area. A wide variation in the ratio of strength to muscle cross-sectional area was observed. This variability may be a result of anatomical differences between subjects or may result from differences in the proportions of different fibre types in the muscles. The variation between subjects is such that strength is not a useful predictive index of muscle cross-sectional area.

Mutations in MERTK, the human orthologue of the RCS rat retinal dystrophy gene, cause retinitis pigmentosa

Mutation of a receptor tyrosine kinase gene, Mertk, in the Royal College of Surgeons (RCS) rat results in defective phagocytosis of photoreceptor outer segments by the retinal pigment epithelium (RPE) and retinal degeneration. We screened the human orthologue, MERTK, located at 2q14.1 (ref. 10), in 328 DNA samples from individuals with various retinal dystrophies and found three mutations in three individuals with retinitis pigmentosa (RP). Our findings are the first conclusive evidence implicating the RPE phagocytosis pathway in human retinal disease.

Histopathological findings and viral tropism in UK patients with severe fatal COVID-19: a post-mortem study

Background

Severe COVID-19 has a high mortality rate. Comprehensive pathological descriptions of COVID-19 are scarce and limited in scope. We aimed to describe the histopathological findings and viral tropism in patients who died of severe COVID-19.

Methods

In this case series, patients were considered eligible if they were older than 18 years, with premortem diagnosis of severe acute respiratory syndrome coronavirus 2 infection and COVID-19 listed clinically as the direct cause of death. Between March 1 and April 30, 2020, full post-mortem examinations were done on nine patients with confirmed COVID-19, including sampling of all major organs. A limited autopsy was done on one additional patient. Histochemical and immunohistochemical analyses were done, and histopathological findings were reported by subspecialist pathologists. Viral quantitative RT-PCR analysis was done on tissue samples from a subset of patients.

Findings

The median age at death of our cohort of ten patients was 73 years (IQR 52–79). Thrombotic features were observed in at least one major organ in all full autopsies, predominantly in the lung (eight [89%] of nine patients), heart (five [56%]), and kidney (four [44%]). Diffuse alveolar damage was the most consistent lung finding (all ten patients); however, organisation was noted in patients with a longer clinical course. We documented lymphocyte depletion (particularly CD8-positive T cells) in haematological organs and haemophagocytosis. Evidence of acute tubular injury was noted in all nine patients examined. Major unexpected findings were acute pancreatitis (two [22%] of nine patients), adrenal micro-infarction (three [33%]), pericarditis (two [22%]), disseminated mucormycosis (one [10%] of ten patients), aortic dissection (one [11%] of nine patients), and marantic endocarditis (one [11%]). Viral genomes were detected outside of the respiratory tract in four of five patients. The presence of subgenomic viral RNA transcripts provided evidence of active viral replication outside the respiratory tract in three of five patients.

Interpretation

Our series supports clinical data showing that the four dominant interrelated pathological processes in severe COVID-19 are diffuse alveolar damage, thrombosis, haemophagocytosis, and immune cell depletion. Additionally, we report here several novel autopsy findings including pancreatitis, pericarditis, adrenal micro-infarction, secondary disseminated mucormycosis, and brain microglial activation, which require additional investigation to understand their role in COVID-19.

Funding

Imperial Biomedical Research Centre, Wellcome Trust, Biotechnology and Biological Sciences Research Council.

Quantitative characterization of the hemodynamic environment in ruptured and unruptured brain aneurysms

BACKGROUND AND PURPOSE

Hemodynamics are thought to play an important role in the mechanisms of aneurysm pathogenesis, progression, and rupture. The purpose of this study was to define quantitative measures related to qualitative flow characteristics previously analyzed and to investigate their relationship to aneurysm rupture.

MATERIALS AND METHODS

The hemodynamic environments in 210 cerebral aneurysms were analyzed by using image-based CFD under different flow conditions. Quantitative hemodynamic variables were defined and extracted from the simulation results. A statistical analysis of the relationship to the previous history of aneurysm rupture was performed, and the variability with flow conditions was assessed.

RESULTS

Ruptured aneurysms were more likely to have larger inflow concentrations, larger MWSS, larger shear concentrations, and lower viscous dissipation ratios than unruptured aneurysms. Areas under low WSS and measures of abnormally low shear force distributions of ruptured and unruptured aneurysms were not statistically different. Although the values of hemodynamic quantities changed with different flow conditions, the statistical differences or ratios between their mean values over the ruptured and unruptured groups were maintained, for both pulsatile and steady flows.

CONCLUSIONS

Concentrated inflow streams and WSS distributions with elevated levels of MWSS and low aneurysmal viscous dissipation are statistically associated with a clinical history of prior aneurysm rupture. In contrast, the area and total viscous shear force applied in the aneurysm region subjected to abnormally low WSS levels are not. This study highlights the potential for image-based CFD for investigating aneurysm-evolution mechanisms and for clinical assessment of aneurysm risks.

Association of hemodynamic characteristics and cerebral aneurysm rupture

BACKGROUND AND PURPOSE

Hemodynamic factors are thought to play an important role in the initiation, growth, and rupture of cerebral aneurysms. This report describes a study of the associations between qualitative intra-aneurysmal hemodynamics and the rupture of cerebral aneurysms.

MATERIALS AND METHODS

Two hundred ten consecutive aneurysms were analyzed by using patient-specific CFD simulations under pulsatile flow conditions. The aneurysms were classified into categories by 2 blinded observers, depending on the complexity and stability of the flow pattern, size of the impingement region, and inflow concentration. A statistical analysis was then performed with respect to the history of previous rupture. Interobserver variability analysis was performed.

RESULTS

Ruptured aneurysms were more likely to have complex flow patterns (83%, P < .001), stable flow patterns (75%, P = .0018), concentrated inflow (66%, P = <.0001), and small impingement regions (76%, P = .0006) compared with unruptured aneurysms. Interobserver variability analyses indicated that all the classifications performed were in very good agreement-that is, well within the 95% CI.

CONCLUSIONS

A qualitative hemodynamic analysis of cerebral aneurysms by using image-based patient-specific geometries has shown that concentrated inflow jets, small impingement regions, complex flow patterns, and unstable flow patterns are correlated with a clinical history of prior aneurysm rupture. These qualitative measures provide a starting point for more sophisticated quantitative analysis aimed at assigning aneurysm risk of future rupture. These analyses highlight the potential for CFD to play an important role in the clinical determination of aneurysm risks.

Bacillus sporulation gene spo0H codes for sigma 30 (sigma H)

The DNA sequences of the spo0H genes from Bacillus licheniformis and B. subtilis are described, and the predicted open reading frames code for proteins of 26,097 and 25,447 daltons, respectively. The two spo0H gene products are 91% identical to one another and about 25% identical to most of the procaryotic sigma factors. The predicted proteins have a conserved 14-amino-acid sequence at their amino terminal end, typical of sigma factors. Antibodies raised against the spo0H gene product of B. licheniformis specifically react with RNA polymerase sigma factor protein, sigma 30, purified from B. subtilis. We conclude that the spo0H genes of B. licheniformis and B. subtilis code for sigma 30, now known as sigma H.

The RNA-binding protein LARP1 is a post-transcriptional regulator of survival and tumorigenesis in ovarian cancer

RNA-binding proteins (RBPs) are increasingly identified as post-transcriptional drivers of cancer progression. The RBP LARP1 is an mRNA stability regulator, and elevated expression of the protein in hepatocellular and lung cancers is correlated with adverse prognosis. LARP1 associates with an mRNA interactome that is enriched for oncogenic transcripts. Here we explore the role of LARP1 in epithelial ovarian cancer, a disease characterized by the rapid acquisition of resistance to chemotherapy through the induction of pro-survival signalling. We show, using ovarian cell lines and xenografts, that LARP1 is required for cancer cell survival and chemotherapy resistance. LARP1 promotes tumour formation in vivo and maintains cancer stem cell-like populations. Using transcriptomic analysis following LARP1 knockdown, cross-referenced against the LARP1 interactome, we identify BCL2 and BIK as LARP1 mRNA targets. We demonstrate that, through an interaction with the 3' untranslated regions (3' UTRs) of BCL2 and BIK, LARP1 stabilizes BCL2 but destabilizes BIK with the net effect of resisting apoptosis. Together, our data indicate that by differentially regulating the stability of a selection of mRNAs, LARP1 promotes ovarian cancer progression and chemotherapy resistance.

A urodynamic view of bladder outflow obstruction in the female: factors influencing the results of treatment

169 female patients with outlet obstruction have been studied urodynamically. The results of treatment of the outlet obstruction in 102 patients have been analysed and the reason for the failures discussed. Patients with stable detrusors and those with symptoms of recurrent urinary tract infection responded well to treatment, provided this relieved the obstruction adequately; symptomatic relief was less common in patients with unstable detrusors, despite adequate outflow readjustment.

Regulation of spo0H, a gene coding for the Bacillus subtilis sigma H factor

The Bacillus spo0H gene codes for sigma H, which, as part of the RNA polymerase holoenzyme E sigma H, is responsible for the transcription of several genes which are expressed at the beginning of the sporulation process. In this communication, we examined the regulation of the spo0H gene of Bacillus subtilis by using lacZ reporter gene assays, quantitative RNA determinations, and Western immunoassay. The expression of the spo0H gene increases as the culture enters the mid-logarithmic stage of growth. This increased expression requires the genes spo0A, spo0B, spo0E, and spo0F, and the requirement for at least spo0A and spo0B can be bypassed when the abrB gene is mutated. The expression of the spo0H gene is constitutive in the presence of the abrB mutation, being expressed at higher levels during vegetative growth. In addition, the sof-1 mutation, in the spo0A structural gene, can bypass the need for spo0F in spo0H expression. The transcriptional start site of spo0H was determined by using RNA made in vivo as well as in vitro. These studies indicate that spo0H is transcribed by the major vegetative RNA polymerase, E sigma A. spo0H RNA and sigma H levels during growth are not identical to each other or to the pattern of expression of spoVG, a gene transcribed by E sigma H. This suggests that spo0H is regulated posttranscriptionally and also that factors in addition to sigma H levels are involved in the expression of genes of the E sigma H regulon.

LARP1 post-transcriptionally regulates mTOR and contributes to cancer progression

RNA-binding proteins (RBPs) bind to and post-transcriptionally regulate the stability of mRNAs. La-related protein 1 (LARP1) is a conserved RBP that interacts with poly-A-binding protein and is known to regulate 5'-terminal oligopyrimidine tract (TOP) mRNA translation. Here, we show that LARP1 is complexed to 3000 mRNAs enriched for cancer pathways. A prominent member of the LARP1 interactome is mTOR whose mRNA transcript is stabilized by LARP1. At a functional level, we show that LARP1 promotes cell migration, invasion, anchorage-independent growth and in vivo tumorigenesis. Furthermore, we show that LARP1 expression is elevated in epithelial cancers such as cervical and non-small cell lung cancers, where its expression correlates with disease progression and adverse prognosis, respectively. We therefore conclude that, through the post-transcriptional regulation of genes such as mTOR within cancer pathways, LARP1 contributes to cancer progression.

A double-blind, randomized controlled trial of the use of imiquimod cream for the treatment of anal canal high-grade anal intraepithelial neoplasia in HIV-positive MSM on HAART, with long-term follow-up data including the use of open-label imiquimod

OBJECTIVE

To determine whether imiquimod was more effective than placebo for the treatment of high-grade anal canal intraepithelial neoplasia (HG-ACIN).

DESIGN

Double-blind, randomized placebo-controlled clinical trial.

METHODS

Sixty-four HIV-positive patients were randomized to self-application of imiquimod cream or matched placebo into the anal canal three times a week for 4 months. Response was assessed by cytology, high-resolution anoscopy and biopsy 2 months after therapy. All patients who failed to resolve were offered treatment with open-label imiquimod for a further 4 months.

RESULTS

Fifty-three patients completed the study, of which 28 patients were on active drug and 25 patients on placebo. In the imiquimod group, four patients resolved and eight patients downgraded to low-grade squamous intraepithelial lesion (LSIL) with a median follow-up of 33 months. In the placebo group, one patient resolved. Imiquimod was significantly associated with a positive outcome (P = 0.003). Only one patient discontinued owing to side effects. Twenty-one patients entered a second open-label phase of treatment. Five of these patients cleared their anal canal intraepithelial neoplasia (ACIN) and four patients downgraded to LSIL. The overall mean duration of follow-up was 36 months. During this extended follow-up period, 61% have exhibited sustained absence of high-grade squamous intraepithelial lesion (HSIL).

CONCLUSION

This study demonstrates the effectiveness of imiquimod for the treatment of ACIN, and the benefit of prolonged or repeated treatments. This form of therapy is likely to be especially valuable for patients with widespread multifocal ACIN who are otherwise difficult to treat, and should be considered as an adjunct to ablative therapy.

Three-dimensional computer-simulated prostate models: lateral prostate biopsies increase the detection rate of prostate cancer

OBJECTIVES

Urologists routinely use the systematic sextant needle biopsy technique to detect prostate cancer. However, recent evidence suggests that this technique has a significant sampling error. We developed a novel three-dimensional (3D) computer-assisted prostate biopsy simulator based on whole-mounted step-sectioned radical prostatectomy specimens to compare the diagnostic accuracy of various prostate needle biopsy protocols.

METHODS

We obtained digital images of 201 step-sectioned whole-mounted radical prostatectomy specimens. 3D computer simulation software was developed to accurately depict the anatomy of the prostate and all individual tumor foci. Additional peripheral devices were incorporated into the system to perform interactive prostate biopsies. We obtained 18 biopsies of each prostate model to determine the detection rates of various biopsy protocols.

RESULTS

The 10- and 12-pattern biopsy protocols had a 99.0% detection rate; the traditional sextant biopsy protocol rate was only 72.6%. The 5-region biopsy protocol had a 90.5% detection rate and the 14-pattern, which includes all the biopsies used in the patterns above, only added 1 additional positive case (99.5%). Transitional zone and seminal vesicle biopsies did not result in a significantly increased detection rate when added to the patterns above. Only one positive model was obtained when the transitional zone biopsies were added. The lateral sextant pattern had a detection rate of 95.5%, and the 4-pattern lateral biopsy protocol had a 93.5% detection rate.

CONCLUSIONS

Our results suggest that all the biopsy protocols that use laterally placed biopsies based on the 5-region anatomic model are superior to the routinely used sextant prostate biopsy pattern. Lateral biopsies in the mid and apical zones of the gland are the most important.

Muscle strength and cross-sectional area in man: a comparison of strength-trained and untrained subjects

This study has examined muscle strength and cross-sectional area in a group of 35 healthy untrained male subjects and 8 subjects who had been engaged in a strenuous weight-training programme. The maximum voluntary knee extension force which could be produced by the untrained subjects was 742 +/- 100 N (mean +/- SD). The trained subjects could produce a significantly (p less than 0.001) greater force (992 +/- 162 N). Cross-sectional area of the knee-extensor muscle group was 81.6 +/- 11.8 cm2 in the untrained subjects and 104.1 +/- 12.3 cm2 in the trained subjects (p less than 0.001). In the untrained subjects, a significant correlation existed between strength and muscle cross-sectional area (r = 0.56, p less than 0.001). In the same group of subjects, there was a significant inverse relationship between muscle cross-sectional area and the ratio of strength to cross-sectional area (r = 0.55, p less than 0.001). The mean ratio of strength to cross-sectional area was 9.20 +/- 1.29 for the untrained group whereas for the trained group this ratio was 9.53 +/- 1.01. It is suggested that the inverse relationship between strength per unit cross-sectional area and cross-sectional area results in part from an increased angle of pennation in the larger muscles.

A quantitative study of cementum removal with hand curettes

An in vitro study was conducted to quantitatively measure the depth of root surface removal using curettes of standardized sharpness and with definite stroke number. Extracted periodontally healthy teeth from patients 10 to 15, 16 to 25, and 26 to 40 years old had periodontal ligament remnants removed with dry gauze before being secured in a vertical position during root planing. The force applied to the root surface was measured with a tension load cell. The "bright line" test was used to assess curette sharpness. After histologic processing, the thickness of cementum adjacent to the root defect, the cementum (if any) in the root defect, total amount of cementum removed, and depth of root defect were measured by a microscopic ocular grid. Teeth from each age range were evenly distributed into 6 groups of 10 teeth each. In the majority of teeth from the 20 stroke group through the 70 stroke group, complete cementum removal was observed at the site of planing. However, in some sections from each group, fragments of cementum remained on the root surface. A positive relationship (r/s = 1) was found between the number of strokes and the force applied to the root surface and the mean depth of defect (P less than 0.05). However, an inverse relationship existed between mean force per stroke and mean defect depth (r/s = -.99) such that as mean force per stroke increased, the mean defect depth decreased. As the root surface became smoother with an increasing number of strokes, the forces increased and were more consistent.(ABSTRACT TRUNCATED AT 250 WORDS)

Cued recall and early identification of dementia

The early detection of dementia carries implications for clinical management for patients and their families and is of utmost concern if an effective pharmacological treatment is to be found. The utility of an enhanced cued recall paradigm for predicting dementia in a group of elderly subjects was examined. Forty-five subjects referred for clinical evaluation who did not meet the criteria for dementia at initial assessment were reassessed 12-18 months later. Eighteen of these subjects were diagnosed as having possible or probable Alzheimer Disease at reassessment and the diagnostic status of 27 remained unchanged. At initial assessment the 'change' group performed more poorly than the 'no change' group on measures of retrieval, acquisition and retention derived from the cued recall procedure. As would be expected, the performance of the 'no change' group remained stable over time whereas the performance of the 'change' group deteriorated, resembling the performance of a group of subjects with mild possible or probable Alzheimer disease. When the sensitivity and specificity of the memory variables were examined, the retrieval measure (i.e., free recall) appeared most useful as an early predictor of dementia. Continued longitudinal evaluations of subjects with questionable dementia are needed to address more fully the natural history of early memory changes associated with dementia.

An examination of driving records in a dementia clinic

The driving records of 249 persons referred to an outpatient dementia clinic were examined retrospectively to assess the specificity of the association between diagnosed dementia and increased traffic accidents. The clinic patients were divided into two groups: those who met criteria for dementia and those who did not. For each group, control subjects matched on age, gender, and location of residence were randomly selected from the records of all drivers in the province. The dementia sample had approximately 2.5 times the traffic crash rate of their matched control sample. The not-demented sample had approximately 2.2 times the traffic crash rate of their matched control sample. These individuals exhibited a variety of psychiatric, neurological, and medical conditions which could have affected their driving, and multiple medical problems were often present. Further clarification of the characteristics of "high risk" drivers is required if effective strategies for maximizing independence while minimizing the risk of traffic crashes are to be realized.

Post-transcriptional control of a sporulation regulatory gene encoding transcription factor sigma H in Bacillus subtilis

The transcriptional regulatory gene spoOH encodes an RNA polymerase sigma factor called sigma H that directs gene expression at an early stage of sporulation in the Gram-positive bacterium Bacillus subtilis. We now report that conditions that induce sporulation cause a rapid increase in the cellular concentration of sigma H. This increase could account for the stimulated transcription of certain sigma H-controlled genes at the onset of sporulation. Experiments in which the expression of spoOH was monitored by use of a spoOH-lacZ fusion and in which expression of spoOH was artificially manipulated by use of an isopropyl-beta-D-thiogalacto-side-inducible promoter indicate that sporulation-induced increases in the amount of sigma H are not controlled at the level of the transcription of its structural gene. Rather, we infer the existence of post-transcriptional control mechanisms that govern sigma H levels, and we present evidence suggesting that increases in the amount of sigma H at the start of sporulation are due to increased translation or stability of the spoOH mRNA and, to a lesser extent, decreased turnover of spoOH protein.

Novel mutations in reverse transcriptase of human immunodeficiency virus type 1 reduce susceptibility to foscarnet in laboratory and clinical isolates

Foscarnet (phosphonoformic acid) is a pyrophosphate analog that inhibits the replication of human immunodeficiency virus type 1 (HIV-1) in vitro and in patients with AIDS. HIV-1 resistance to foscarnet has not been reported despite long-term foscarnet therapy of AIDS patients with cytomegalovirus disease. We therefore attempted to select foscarnet-resistant HIV-1 in vitro by serial endpoint passage of virus in 400 microM foscarnet. After 13 cycles of passage in MT-2 cells, virus exhibiting > or = 8.5-fold foscarnet resistance was isolated. The reverse transcriptase (RT) from resistant virions exhibited a similar level of foscarnet resistance in enzyme inhibition assays (approximately 10-fold resistance). Foscarnet-resistant virus showed increased susceptibility to 3'-azido-3'-deoxythymidine (90-fold) and to the HIV-1-specific RT inhibitors TIBO R82150 (30-fold) and nevirapine (20-fold). DNA sequence analysis of RT clones from resistant virus revealed the coexistence of two mutations in all clones: Gln-161 to Leu (CAA to CTA) and His-208 to Tyr (CAT to TAT). Sequence analysis of six clinical HIV-1 isolates showing reduced susceptibility to foscarnet revealed the Tyr-208 mutation in two, the Leu-161 mutation in one, and a Trp-88-to-Ser or -Gly mutation in four isolates. Site-specific mutagenesis and production of mutant recombinant viruses demonstrated that the Leu-161, Ser-88, and Tyr-208 mutations reduced HIV-1 susceptibility to foscarnet 10.5-, 4.3-, and 2.4-fold, respectively, in MT-2 cells. In the crystal structure of HIV-1 RT, the Gln-161 residue lies in the alpha E helix beneath the putative deoxynucleoside triphosphate (dNTP) binding site. The Gln-161-to-Leu mutation may affect the structure of the dNTP binding site and its affinity for foscarnet. The location of the Trp-88 residue in the Beta5a strand of HIV-1 RT suggest that the Ser-88 mutation affects template-primer binding, as do several mutations that affect RT susceptibility to nucleoside analogs.

Quantifying comorbidity in a disease-specific cohort: adaptation of the total illness burden index to prostate cancer

OBJECTIVES

Numerous studies have demonstrated the importance of comorbid illness when analyzing medical outcomes. The purpose of this study was to adapt a generic comorbidity index, the Total Illness Burden Index (TIBI), for use in men with prostate cancer, and to evaluate the usefulness of the new instrument in adjusting for the impact of comorbidity on functional outcomes in a prostate cancer cohort.

METHODS

The TIBI uses patients' self-report of symptoms and diagnoses to determine not only the presence but also the severity of comorbidities in each of 16 body system domains. To create the TIBI-P (prostate cancer modification), some domains were added and others were modified according to clinical criteria. The TIBI-P was completed by 1638 men with prostate cancer followed up longitudinally in 29 urology practices in the United States. TIBI-P scores were calculated for each patient and analyzed with scores on the SF-36 quality-of-life questionnaire and with patient report of days confined to bed.

RESULTS

After adjusting for age and income, lower SF-36 scale scores and increases in confinement to bed were associated with a greater burden of comorbid illness as measured by the TIBI-P, independent of the extent of prostate cancer. The TIBI-P explained 24% of the variance in the SF-36 physical functioning domain score.

CONCLUSIONS

The TIBI-P is a powerful measure of the impact of comorbid illness on the quality of life and functioning among patients with prostate cancer. This index may prove valuable in research on clinical and economic outcomes of prostate cancer.

Prevalence of protein-energy malnutrition at diagnosis in children with acute lymphoblastic leukemia

BACKGROUND

The purpose of the present study was to test the hypothesis that protein-energy undernutrition is common in patients with acute lymphoblastic leukemia at diagnosis. Previous studies have failed to establish whether undernutrition is a common feature at diagnosis.

METHODS

Body mass index (BMI, weight/height2), expressed as a standard deviation score (SDS) relative to contemporary United Kingdom reference data, was used as the index of nutritional status. The index was calculated in a national cohort of standard-risk patients (n = 1019) treated in the same protocol in the United Kingdom.

RESULTS

Prevalence of undernutrition (defined as BMI SDS <-2.0) exceeded expected frequencies in boys (7.6%) and girls (6.7%). These differences were statistically significant (p < 0.001), with a 95% confidence interval for the prevalence of undernutrition of 5.8% to 9.0%.

CONCLUSIONS

Undernutrition is relatively common in patients with newly diagnosed acute lymphoblastic leukemia, with a threefold excess of patients below the cutoff used to define undernutrition. Screening for undernutrition at diagnosis of acute lymphoblastic leukemia is indicated, and the BMI SDS is a simple index of nutritional status that could be readily calculated using measurements routinely made at diagnosis. The same simple screening technique could also be used clinically to detect and manage or prevent overnutrition (obesity), which is common in these patients after diagnosis.