Beliefs about inevitable decline among home-living older adults at risk of malnutrition: a qualitative study

BACKGROUND

Approximately 14% of free-living adults aged ≥65 years are at risk of malnutrition. Malnutrition screen and treat interventions in primary care are few, show mixed results, and the advice given is not always accepted and followed. We need to better understand the experiences and contexts of older adults when aiming to develop interventions that are engaging, optimally persuasive and relevant.

METHODS

Using the Person-based Approach, we carried out 23 semi-structured interviews with purposively selected adults ≥65 years with chronic health or social conditions associated with malnutrition risk. Thematic analysis informed the development of key principles to guide planned intervention development.

RESULTS

We found that individuals' beliefs about an inevitable decline in appetite and eating in older age compound the many and varied physical and physiological barriers that they experience. Also, we found that expectations of decline in appetite and physical ability may encourage resignation, reduce self-efficacy to overcome barriers, and reduce motivation to address weight loss and/or recognise it as an issue that needs to be addressed. Fear of loss of independence may also reduce the likelihood of asking general practitioners for advice.

CONCLUSIONS

The key findings identified include a sense of resignation, multiple different barriers to eating and a need for independence, each underpinned by the expectation of a decline in older adulthood. Interventions need to address misperceptions about the inevitability of decline, highlight how and why diet recommendations are somewhat different from recommendations for the general population, and suggest easy ways to increase food intake that address common barriers.

Random variation in rectal position during radiotherapy for prostate cancer is two to three times greater than that predicted from prostate motion

Objective:

Radiotherapy for prostate cancer does not explicitly take into account daily variation in the position of the rectum. It is important to accurately assess accumulated dose (D_A) to the rectum in order to understand the relationship between dose and toxicity. The primary objective of this work was to quantify systematic (Σ) and random (σ) variation in the position of the rectum during a course of prostate radiotherapy.

Methods:

The rectum was manually outlined on the kilo-voltage planning scan and 37 daily mega-voltage image guidance scans for 10 participants recruited to the VoxTox study. The femoral heads were used to produce a fixed point to which all rectal contours were referenced.

Results:

Σ [standard deviation (SD) of means] between planning and treatment was 4.2 mm in the anteroposterior (AP) direction and 1.3 mm left–right (LR). σ (root mean square of SDs) was 5.2 mm AP and 2.7 mm LR. Superior–inferior variation was less than one slice above and below the planning position.

Conclusion:

Our results for Σ are in line with published data for prostate motion. σ, however, was approximately twice as great as that seen for prostate motion. This suggests that D_A may differ from planned dose in some patients treated with radiotherapy for prostate cancer.

Advances in knowledge:

This work is the first to use daily imaging to quantify Σ and σ of the rectum in prostate cancer. σ was found to be greater than published data, providing strong rationale for further investigation of individual D_A.

The tension band principle and angular testing of extensor tendon repairs

Extensor tendons in the finger are flat and not amenable to repair by core and epitendinous sutures. Mattress sutures and Kessler repairs without epitendinous stitching are often used for extensor tendon divisions in the fingers. Except when in full extension, the finger presents a series of curved surfaces (at each joint) to the tendon. It was hypothesized that extensor tendons are subject to the 'tension band' principle and that they might be amenable to repair by dorsal-only epitendinous sutures. A Silfverskiöld dorsal-only repair was compared with mattress and Kessler repairs in vitro on a curvilinear testing apparatus. The epitendinous technique was found to be significantly more resistant to gapping and rupture, as well as more resistant to deformation (i.e. stiffer) than the conventional techniques.

Kinetic isotope effects and ligand binding in PQQ-dependent methanol dehydrogenase

The reaction of PQQ (2,7,9-tricarboxypyrroloquinoline quinone)-dependent MDH (methanol dehydrogenase) from Methylophilus methylotrophus has been studied under steady-state conditions in the presence of an alternative activator [GEE (glycine ethyl ester)] and compared with similar reactions performed with ammonium (used more generally as an activator in steady-state analysis of MDH). Studies of initial velocity with methanol (protiated methanol, C1H3O1H) and [2H]methanol (deuteriated methanol, C2H3O2H) as substrate, performed with different concentrations of GEE and PES (phenazine ethosulphate), indicate competitive binding effects for substrate and PES on the stimulation and inhibition of enzyme activity by GEE. GEE is more effective at stimulating activity than ammonium at low concentrations, suggesting tighter binding of GEE to the active site. Inhibition of activity at high GEE concentration is less pronounced than at high ammonium concentration. This suggests a close spatial relationship between the stimulatory (KS) and inhibitory (KI) binding sites in that binding of GEE to the KS site sterically impairs the binding of GEE to the KI site. The binding of GEE is also competitive with the binding of PES, and GEE is more effective than ammonium in competing with PES. This competitive binding of GEE and PES lowers the effective concentration of PES at the site competent for electron transfer. Accordingly, the oxidative half-reaction, which is second-order with respect to PES concentration, is more rate-limiting in steady-state turnover with GEE than with ammonium. The smaller methanol C-1H/C-2H kinetic isotope effects observed with GEE are consistent with a larger contribution made by the oxidative half-reaction to rate limitation. Cyanide is much less effective at suppressing 'endogenous' activity in the presence of GEE than with ammonium, which is attributed to impaired binding of cyanide to the catalytic site through steric interaction with GEE bound at the KS site. The kinetic model developed previously for reactions of MDH with ammonium [Hothi, Basran, Sutcliffe and Scrutton (2003) Biochemistry 42, 3966-3978] is consistent with data obtained with GEE, although a more detailed structural interpretation is given here. Molecular-modelling studies rationalize the kinetic observations in terms of a complex binding scenario at the molecular level involving two spatially distinct inhibitory sites (KI and KI'). The KI' site caps the entrance to the active site and is interpreted as the PES binding site. The KI site is adjacent to, and, for GEE, overlaps with, the KS site, and is located in the active-site cavity close to the PQQ cofactor and the catalytic site for methanol oxidation.

Transcriptome-wide mutation discovery in patients in a phase II clinical trial of first-line erlotinib for clinically selected patients with advanced non-small cell lung cancer

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Background: The purpose of this study was to clinically select a population of patients (pts) likely to benefit from erlotinib and to perform extensive genetic profiling of fresh tissue tumour to identify predictive biomarkers. Methods: Treatment was erlotinib 150 mg p.o. daily until disease progression. Eligibility criteria included: stage IIIB/IV NSCLC; no prior chemo; ECOG ≤2; at least 2 of the following 4 criteria: women, never-smokers, Southeast Asian origin, adenocarcinoma and/or BAC. All pts had baseline serum samples and a fresh frozen tumour biopsy. EGFR and KRAS were sequenced using traditional methods to identify known mutations of erlotinib. Transcribed coding regions of all other expressed genes were sequenced to uncover novel mutations and other genetic features. Results: From Sept-06 to Oct-08, 65 pts have been enrolled. Of these 60 have completed at least 8 wks of erlotinib (or progressed before 8 wks). 49F and 11M; 45 never smokers. PS 0/1/2: 10/39/11. 18 Caucasian and 42 Asian. Pathology: 44 ACA; 3 BAC;1 squamous carcinoma; 13 NSCLC NOS. Responses: PR - 21 (35%); SD - 24 (DCR 75%); PD - 10; NE - 5. 85% did not progress at 8 weeks. 19 of 51 (37%) pre-treatment samples had an EGFR mutation. 10 of the 28 pts with response data (24pts still on drug) had a PR and 7 of these had either an LREA deletion or L858R point mutation. 1 of 3 post-treatment samples developed a T790M mutation on erlotinib. 3 of 51 pts have KRAS mutations. Analysis of over 21 Giga basepairs of aligned transcriptome sequencing data from 20 tumour samples has uncovered 1089 putative non-conservative gene mutations of which 15 are seen in multiple tumours: TUBA1C, EPS8L1, ARID4B, RPL22, C20orf52, CCT8, HLA-DRB5, TRIP6, and PLP2 in 4 tumours, C20orf52 and CTSL1 in 5 tumours, and SERF2, TMEM173, and an uncharacterized gene in 6 tumours. Conclusions: Clinical selection of pts enriches the EGFR mutation positive and KRAS mutation negative population and leads to high rates of non-progression. Full tumour RNA analysis identified several recurrent mutations that may describe mechanisms of erlotinib response and resistance. The discovery of novel mutations in multiple pts suggests patterns that may shed light on lung cancer specific behaviour.

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Previously documented mutations in the epidermal growth factor receptor (EGFR) gene in a non-small cell lung cancer (NSCLC) population treated with gefitinib are not associated with response

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Background: Mutations in the tyrosine kinase domain of EGFR that may correlate with clinical features and response of NSCLC to EGFR tyrosine kinase inhibitors have been described. But, varying methodologies have contributed to an uncertain relationship between EGFR mutational status and response. This study sought to characterize EGFR mutations in microdissected tumour tissue from pts with advanced NSCLC treated with gefitinib and correlate their clinical data. Methods: Biopsy material from pts treated with gefitinib for advanced NSCLC at the British Columbia Cancer Agency was analyzed. Malignant cells (cytology specimens) or tissue (paraffin embedded biopsies) was reviewed and tumour cells isolated by laser- capture microdissection or manual scrape. Genomic DNA was extracted and exons coding for the EGFR tyrosine kinase domain (18 - 24) were amplified by PCR and sequenced. When insufficient, the priority was 18, 19, 21, followed by 20, 23, 22, and 24. EGFR mutational analyses were correlated with response to gefitinib and clinical features. Results: 61 pts were identified, 14 (23%) radiological responders (CR, PR): 10 Asian, 10 female, 8 non-smokers, 8 adenocarcinoma, 2 BAC. Of 51 tumour samples available, 39 had adequate tissue for sequencing analysis. EGFR copy number by FISH is pending. Laser-capture microdissection allowed for high quality DNA to be extracted almost exclusively from tumour. Exons 18, 19, 20, 21, 22, 23 and 24 have been sequenced in 37, 34, 30, 33, 12, 10, and 13 patients, respectively. 4 mutations were identified: 2 in 2 non-smoking Asian pts (exon 19; deletion or substitution of L747-T751) and 2 in Caucasians (exon 20 point mutation resulting in a L798F substitution). None of these pts had a response to gefitinib. Conclusions: As with other series, most responders were female, non-smokers of Asian origin. Our results support the relationship between Asian ethnicity and EGFR mutations but question the role of EGFR mutational status in predicting response. Prospective studies will need to focus the detection of additional genetic features using accurate and reproducible techniques before recommendations for selecting populations to be treated can be made.

No significant financial relationships to disclose.

Twin-twin transfusion syndrome in a dizygotic monochorionic-diamniotic twin pregnancy

We present a case of twin-twin transfusion syndrome with discordant gender. Monochorionicity was confirmed by surgical pathology. Cytogenetic analysis showed normal 46,XX and 46,XY karyotypes. Microsatellite analysis using reliable pericentromeric markers was consistent with dispermic fertilization of two separate ova. This suggests that monochorionicity, rather than zygosity, may be responsible for the development of placental vascular anastomoses.

Survey of methods of teaching and learning in undergraduate pharmacology within UK higher education

Many of the pharmacology teachers surveyed in a questionnaire on pharmacology teaching and learning are aware of nontraditional teaching and learning methods and believe they are both appropriate to the discipline and effective in producing learning gain in the students. The reasons that nontraditional teaching methods are not used extensively include a shortage of staff time together with a perception that nontraditional teaching methods are staff-time intensive, a lack of effective motivation and reward of staff by their institutions for implementing nontraditional teaching methods and a shortage of the appropriate facilities and resources required. The questionnaire and its results are discussed in this article.

Steady-state and picosecond-time-resolved fluorescence studies on the recombinant heme domain of Bacillus megaterium cytochrome P-450

The conformational changes associated with the interaction of sodium laurate with the recombinant heme domain for cytochrome P-450BM3 have been investigated by steady-state and picosecond-time-resolved fluorescence spectroscopy. The steady-state quenching experiments show that while all the five tryptophan residues are accessible to acrylamide in the free enzyme as well as the enzyme x substrate complex, the number of tryptophan residues accessible to ionic quenchers decreases on interaction of the substrate with the enzyme. This indicates that some of the tryptophan residues move towards the core of the protein on interaction with the substrate. The number of tryptophan residues accessible to the solvent as determined by the calculation of the solvent-accessible area for the free enzyme agrees with the values obtained by the quenching experiments. The time-resolved fluorescence studies carried out by means of the time-correlated single-photon-counting technique show that the fluorescence-decay curve is best fitted to a three-exponential model (0.2, 1.0 and 5.4 ns). Lifetime distributions, as recovered by the maximum-entropy method, agree with the discrete exponential model. The binding of the substrate does not lead to any significant change in the lifetime components of the enzyme, indicating that the tryptophan residues are possibly away from the substrate-binding domain. The decay-associated emission spectra and the magnitudes of amplitude of different lifetimes indicate that the shortest lifetime component (tau1) originates from the three tryptophan residues that are completely or partially accessible to the solvent, and tau2 originates from the tryptophan residues that are buried in the core of the enzyme and not accessible to the solvent. X-ray crystallographic data and solvent-acessible-area calculations have been used to identify these residues.

Uniparental isodisomy of chromosome 14 in two cases: an abnormal child and a normal adult

Uniparental disomy (UPD) of a number of different chromosomes has been found in associated with abnormal phenotypes. A growing body of evidence for an imprinting effect involving chromosome 14 has been accumulating. We report on a case of paternal UPD of chromosome 14 studied in late gestation due to polyhydramnios and a ventral wall hernia. A prenatal karyotype documented a balanced Robertsonian 14:14 translocation. The baby was born prematurely with hairy forehead, retrognathia, mild puckering of the lips and finger contractures. Hypotonia has persisted since birth and at age one year, a tracheostomy for laryngomalacia and gastrostomy for feeding remain necessary. Absence of maternal VNTR polymorphisms and homozygosity of paternal polymorphisms using chromosome 14 specific probes at D14S22 and D14S13 loci indicated paternal uniparental isodisomy (pUPID). Parental chromosomes were normal. We also report on a case of maternal UPD in a normal patient with a balanced Robertsonian 14:14 translocation and a history of multiple miscarriages. Five previous reports of chromosome 14 UPD suggest that an adverse developmental effect may be more severe whenever the UPD is paternal in origin. This is the second reported patient with paternal UPD and the fifth reported with maternal UPD, and only few phenotypic similarities are apparent. Examination of these chromosome 14 UPD cases of maternal and paternal origin suggests that there are syndromic imprinting effects.

Selective reovirus infection of murine hepatocarcinoma cells during cell division. A model of viral liver infection

Reovirus type 1, strain Lang (1/L), can infect hepatocytes in vivo only after hepatocellular damage is induced by hepatotoxins, surgical trauma, resection, or profound immunosuppression. To examine the role of cell cycle and cellular differentiation on liver cell susceptibility to reovirus infection, a murine hepatocarcinoma cell line, Hepa 1/A1, was infected with reovirus and assayed for the presence of infectious virus or reovirus antigen in cells. Despite a > 95% binding of reovirus to hepatocarcinoma cells as indicated by cytometric analysis; only 10% of hepatoma cells contained infectious virus by infectious center assay. In comparison, 100% of L cells were infected. Analysis of intracellular reovirus antigen revealed its presence in dividing but not in quiescent hepatocytes. This correlation of cellular division and cell capacity to support viral replication suggests that induction of hepatocyte proliferation may be a mechanism for liver susceptibility to reovirus infection.

18th Sir Hans Krebs lecture. Knowledge-based protein modelling and design

A systematic technique for protein modelling that is applicable to the design of drugs, peptide vaccines and novel proteins is described. Our approach is knowledge-based, depending on the structures of homologous or analogous proteins and more generally on a relational data base of protein three-dimensional structures. The procedure simultaneously aligns the known tertiary structures, selects fragments from the structurally conserved regions on the basis of sequence homology, aligns these with the 'average structure' or 'framework', builds on the loops selected from homologous proteins or a wider database, substitutes sidechains and energy minimises the resultant model. Applications to modelling an homologous structure, tissue plasminogen activator on the basis of another serine proteinase, and to modelling an analogous protein, HIV viral proteinase on the basis of aspartic proteinases, are described. The converse problem of ab initio design is also addressed: this involves the selection of an amino acid sequence to give a particular tertiary structure, in this case a symmetrical domain of two Greek-key motifs.

Cephalexin levels in human bile in presence of biliary tract disease

Cephalexin was given to 24 patients before and after operation on the bile ducts and gall bladder. Two patients had obstructive jaundice. Samples of the bile were taken either directly from the gall bladder at operation or via the T-tube. Cephalexin was excreted in the bile, peak levels being obtained after two to three hours. These levels could be raised if probenecid was given concurrently. Higher levels were found in patients with functioning gall-bladders. A trial of cephalexin seems justified for the treatment of typhoid carriers.