Pharyngeal Constrictor Dose-Volume Histogram Metrics and Patient-Reported Dysphagia in Head and Neck Radiotherapy

AIMS

Head and neck radiotherapy long-term survival continues to improve and the management of long-term side-effects is moving to the forefront of patient care. Dysphagia is associated with dose to the pharyngeal constrictors and can be measured using patient-reported outcomes to evaluate its effect on quality of life. The aim of the present study was to relate pharyngeal constrictor dose-volume parameters with patient-reported outcomes to identify prognostic dose constraints.

MATERIALS AND METHODS

A 64-patient training cohort and a 24-patient testing cohort of oropharynx and nasopharynx cancer patients treated with curative-intent chemoradiotherapy were retrospectively examined. These patients completed the MD Anderson Dysphagia Inventory outcome survey at 12 months post-radiotherapy to evaluate late dysphagia: a composite score lower than 60 indicated dysphagia. The pharyngeal constrictor muscles were subdivided into four substructures: superior, middle, inferior and cricopharyngeal. Dose-volume histogram (DVH) metrics for each of the structure combinations were extracted. A decision tree classifier was run for each DVH metric to identify dose constraints optimising the accuracy and sensitivity of the cohort. A 60% accuracy threshold and feature selection method were used to ensure statistically significant DVH metrics were identified. These dose constraints were then validated on the 24-patient testing cohort.

RESULTS

Existing literature dose constraints only had two dose constraints performing above 60% accuracy and sensitivity when evaluated on our training cohort. We identified two well-performing dose constraints: the pharyngeal constrictor muscle D63% < 55 Gy and the superior-middle pharyngeal constrictor combination structure V31Gy < 100%. Both dose constraints resulted in ≥73% mean accuracy and ≥80% mean sensitivity on the training and testing patient cohorts. In addition, a pharyngeal constrictor muscle mean dose <57 Gy resulted in a mean accuracy ≥74% and mean sensitivity ≥60%.

CONCLUSION

Mid-dose pharyngeal constrictor muscle and substructure combination dose constraints should be used in the treatment planning process to reduce late patient-reported dysphagia.

Pre-Transplant Marital Status and Hematopoietic Cell Transplantation Outcomes

Background

Evidence about the impact of marital status before hematopoietic cell transplantation (hct) on outcomes after hct is conflicting.

Methods

We identified patients 40 years of age and older within the Center for International Blood and Marrow Transplant Research registry who underwent hct between January 2008 and December 2015. Marital status before hct was declared as one of: married or living with a partner, single (never married), separated or divorced, and widowed. We performed a multivariable analysis to determine the association of marital status with outcomes after hct.

Results

We identified 10,226 allogeneic and 5714 autologous hct cases with, respectively, a median follow-up of 37 months (range: 1-102 months) and 40 months (range: 1-106 months). No association between marital status and overall survival was observed in either the allogeneic (p = 0.58) or autologous (p = 0.17) setting. However, marital status was associated with grades 2-4 acute graft-versus-host disease (gvhd), p < 0.001, and chronic gvhd, p = 0.04. The risk of grades 2-4 acute gvhd was increased in separated compared with married patients [hazard ratio (hr): 1.13; 95% confidence interval (ci): 1.03 to 1.24], and single patients had a reduced risk of grades 2-4 acute gvhd (hr: 0.87; 95% ci: 0.77 to 0.98). The risk of chronic gvhd was lower in widowed compared with married patients (hr: 0.82; 95% ci: 0.67 to 0.99).

Conclusions

Overall survival after hct is not influenced by marital status, but associations were evident between marital status and grades 2-4 acute and chronic gvhd. To better appreciate the effects of marital status and social support, future research should consider using validated scales to measure social support and patient and caregiver reports of caregiver commitment, and to assess health-related quality of life together with health care utilization.

A study of human neutrophil antigen genotype frequencies in Hong Kong

BACKGROUND

Alloantibodies against human neutrophil antigens (HNA) are associated with a variety of clinical conditions. Over the past decade, the allelic and genotypic frequencies of the five HNA systems have been evaluated. Although the HNA system is less polymorphic than human leukocyte antigens (HLA), significant differences in the genotypic and allele frequencies still exist in different populations, even those living in close proximity.

OBJECTIVES

To delineate HNA genotypic and allele frequencies to provide vital information on estimating the risk of HNA-associated diseases for our local population.

METHODS

Using a validated, in-house-developed assay, genotyping for HNA-1, HNA-3, HLA-4 and HNA-5 was performed on 300 samples from Chinese blood donors from Hong Kong. In addition, the frequency of the HNA-2 c.843A > T allele was also determined.

RESULTS

The allele frequencies of HNA-1a, -1b and -1c alleles were 67·8, 31·5 and 0%, respectively, whereas the frequencies of HNA-3a and HNA-3b were 71·0 and 29·0%, respectively. The frequencies of HNA-4a and -4b alleles were 99·5 and 0·5%, respectively, and for HNA-5a and -5b, alleles were 85·2 and 14·8%, respectively. Homozygotes for the HNA-2 c.843 TT variant were absent in our population, whereas only <4% of the population were c.843AT heterozygote carriers.

CONCLUSIONS

This is the first study to define HNA genotype and allele frequencies using a validated modified in-house PCR-SSP method in the Hong Kong Chinese blood donor population. Our approach provides a cost-effective assay for conducting routine HNA typing and facilitates the incorporation of these assays into routine clinical service. Our results are comparable with those reported in the Guangzhou Chinese population, but the allele frequencies in our Hong Kong Chinese population are significantly different from the reported European frequencies, confirming that a geographical difference exists for HNA allele frequencies.

Identification of the novel HLA-B*39:01:01:04 allele in a Chinese individual by sequence-based typing

The new HLA-B*39:01:01:04 allele differs from HLA-B*39:01:01 by a C → T substitution in intron 1.

Identification of a novel HLA-A*02:06:01:02 allele in a Chinese individual by sequence-based typing

The new HLA-A*02:06:01:02 allele differs from HLA-A*02:06:01 by a C→G substitution in Intron 1.

Detection of HLA-B*58:01, the susceptible allele for allopurinol-induced hypersensitivity, by loop-mediated isothermal amplification

BACKGROUND

Allopurinol, a common medication for gout treatment, can cause rare but life-threatening severe cutaneous adverse reactions. A strong pharmacogenetic association of human leucocyte antigen (HLA)-B*58:01 with allopurinol-induced drug hypersensitivity has been reported, especially in the Han Chinese population.

OBJECTIVES

To develop a rapid and simple loop-mediated isothermal amplification (LAMP) assay of HLA-B*58:01 and evaluate its feasibility in predicting allopurinol-induced drug hypersensitivity.

METHODS

Two sets of LAMP primers targeting exons 2 and 3 of HLA-B*58:01 were designed. DNA extracted from 20 clinical blood samples of patients with gout was used to evaluate the effectiveness of the two LAMP primer sets for the detection of HLA-B*58:01.

RESULTS

The results were compared with routine clinical genotyping methods. All extracted DNA samples tested with the HLA-B*58:01 LAMP assay showed agreement with the routine genotyping results. No amplifications were observed when unextracted blood samples were tested.

CONCLUSIONS

The HLA-B*58:01 LAMP assay was confirmed to be simple, rapid and specific for the detection of HLA-B*58:01, and therefore of potential value in the diagnosis of allopurinol-induced hypersensitivity.

Loop-mediated isothermal amplification for detection of HLA-B*58:01 allele

Strong association of human leukocyte antigen (HLA)-B*58:01 allele with allopurinol-induced hypersensitivity was found worldwide, especially in the Han Chinese populations. This study aims to develop and evaluate a loop-mediated isothermal amplification (LAMP) assay for rapid detection of HLA-B*58:01. Two sets of LAMP primers targeting exons 2 and 3 of HLA-B*58:01 allele were designed and their annealing temperatures were optimized accordingly. The heating devices for LAMP assay were tested. The analytical sensitivities of the two sets of LAMP primers were determined by 1:10 serial dilution of a positive control with homozygous HLA-B*58:01 allele from 100 ng down to 1 fg. The analytical specificities of the LAMP primers were evaluated by 30 selected University of California, Los Angeles (UCLA) DNA Exchange Program samples with known HLA-B loci typings previously typed by sequencing. Both sets of LAMP primers targeting exons 2 and 3 amplified optimally at 67°C. Thermal cycler is essential in achieving a more precise and specific LAMP result. The sensitivity of the exon 2 LAMP primer set was found to be 1 pg, whereas it was 10 ng for the exon 3 primer set in a 60-min amplification. The LAMP primers were highly specific because LAMP results were perfectly concordant to the sequencing results. The HLA-B*58:01 LAMP assay has compatible sensitivity and specificity to routine genotyping assays, and it is potentially an alternative screening test for the detection of HLA-B*58:01 and ultimately allopurinol-induced hypersensitivity.

Effectiveness of multifaceted fall-prevention programs for the elderly in residential care

BACKGROUND

Unintentional falls are particularly prevalent among older people and constitute a public health concern. Not much is known about the implications of multifaceted intervention programs implemented in residential care settings.

OBJECTIVES

To evaluate the effectiveness of multifaceted intervention programs in reducing the number of falls, fallers, recurrent fallers, and injurious falls among older people living in residential care facilities.

SEARCH STRATEGY

Comprehensive searches of Medline, PubMed, and EMBASE up to July 2007, the cited literature lists of each included study, and the internet engines Google Scholar, Yahoo, and Dogpile were performed to identify eligible studies.

SELECTION CRITERIA

Eligible studies for this review were those that had randomized, controlled trials with adequate follow-up study components in their design. Studies that included elderly people in residential care who participated in multifaceted falls-prevention programs were included.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the necessary data. Studies were assessed for quality by the criteria of Downs and Black. The results of the included studies have been reviewed narratively.

MAIN RESULTS

From 21 articles potentially relevant to the topic, five studies met the inclusion criteria and all were reasonably well conducted. Three reported significant reductions in the number of recurrent fallers, two reported significant reductions in the number of falls, and one reported significant reductions in the number of fallers. One other reported a reduction in the number of injurious falls in those who received the multifaceted prevention program compared with the control group. However, the analyses of this specific study were not based on intent-to-treat, so the effect of intervention on the number of injurious falls remains inconclusive. No study reported on adverse events, costs, or sustainability of the interventions.

CONCLUSIONS

Multifaceted programs that encompass a wide range of intervention strategies have shown some evidence of efficacy. However, more well-designed research is required that assesses effects on injurious falls, quality of life, cost-effectiveness, and sustainability.

Unnecessary repeat requesting of tests: an audit in a government hospital immunology laboratory

Unnecessary repeat requesting of tests can make up a large proportion of a laboratory's workload. This audit set out to establish the size of this problem and to identify the circumstances under which these repeat requests were made in a government tertiary hospital immunology laboratory. The numbers of tests for immunoglobulin measurement, common autoantibodies, and tumour markers that were repeated over a 12 month period were analysed by interrogating the Delphic laboratory computer system using a management information system for raw data enquiry protocol. Repeat requests within 12 weeks of a previous request made up 16.78% of the total workload. The total cost of the tests was estimated at 132 151 US dollars. The waste of technician time and reagents as a result of unnecessary repeat testing is excessive. Many of these tests might be eliminated with the use of interventions such as computerised reminders.

Shear-induced platelet activation and adhesion on human pulmonary artery endothelial cells seeded onto hydrophilic polymers

We evaluated platelet activation and adhesion on two plasma polymerized surfaces, N-vinyl pyrrolidone (NVP) and gamma-butyro lactone (GBL), which have been shown previously to promote endothelial cell growth and adhesion as well as fibronectin-coated glass (1 microg/cm(2)) coverslips. Human pulmonary artery endothelial cells were seeded onto coverslips at a low density ( approximately 20,000 cells/cm(2)) and grown to confluence (3-5 days). The materials, both with and without ECs, were then exposed to a shear rate of 400 s(-1) in a closed loop recirculating flow system containing human platelet-rich plasma. Plasma samples were taken at 0, 5, 15, 30, and 60 min and analyzed for platelet and coagulation activation. The coverslips were examined for EC coverage and platelet adherence. EC retention over a 1-h period was approximately 75% for all three materials. All three materials without ECs were highly platelet activating having similar P-selectin expression, platelet factor 4 (PF4) release, mepacrine uptake, and microparticle production. Both microparticle production and platelet adhesion were significantly lower in EC-seeded materials. Dense granule and PF4 release were both slightly diminished in all three materials seeded with ECs. P-selectin expression was reduced slightly for GBL, but remained the same for the other two materials. The EC-seeded materials displayed favorable characteristics with respect to platelet activation and adhesion; however, they still demonstrated some thrombogenic tendencies due to EC loss and exposure of the underlying substrate. Therefore, both EC coverage and EC hemostatic function are important factors in determining the thromboresistance of an EC-seeded surface.

In vitro dedifferentiation of fetal porcine pancreatic tissue prior to transplantation as islet-like cell clusters

The fetal porcine pancreas under experimental conditions can be transplanted in the form of explants or islet-like cell clusters (ICCs) to normalize blood glucose levels in diabetic recipients. ICCs are released from the collagenase-digested pancreas and require a 4- to 5-day culture period for their complete formation. In order to maximize insulin producing beta cell differentiation following transplantation, an understanding of ICC development is essential to utilize this alternative treatment for type 1 diabetes. In this study a role is proposed for exocrine cells in the generation of the multipotent pancreatic precursor cells during the culture period. Acinar cells undergo dedifferentiation during the initial stages of the culture period into multipotent pancreatic precursor cells, previously called protodifferentiated cells. The progressive loss of exocrine differentiation appears to involve rapid degranulation of zymogen granules by exocytosis and loss of the prominent secretory apparatus. These processes occur in parallel with a significant reduction in the expression of lipase in the period from day 0 to day 5 and simultaneously there is an increase in the epithelioid/ductal cell marker, cytokeratin 20. Using proliferating cell nuclear antigen, cell proliferation during the culture period does not appear to account for the increase in epithelioid/ductal cells. Further the rates of apoptosis and necrosis which were identified using the TUNEL technique and propidium iodide, respectively, do not appear to account for the reduction in exocrine cell numbers. Exocrine cell dedifferentiation appears to increase the pool of protodifferentiated cells which have the potential to develop into the insulin-producing beta-cell population following transplantation into the diabetic recipient

Helper T-lymphocyte precursor frequency predicts the occurrence of graft-versus-host disease and disease relapse after allogeneic bone marrow transplantation from HLA-identical siblings

BACKGROUND AND OBJECTIVES

Donor helper T-lymphocytes may be involved in graft-versus-host disease (GVHD) and a graft-versus-leukemia effect after bone marrow transplantation (BMT). We assayed donor helper T-lymphocyte precursor frequencies (HTLP(f)) to see whether they could predict the severity of GVHD and disease relapse after transplantation, thereby facilitating donor selection, pre-transplant counselling and modification of GVHD prophylaxis after BMT.

DESIGN AND METHODS

Thirty-six consecutive adult BMT recipients and their HLA-identical sibling donors were recruited. HTLP((f)) was measured as a function of interleukin-2 secretion by alloreactive donor T-cells using a limiting dilution assay. Patients were followed prospectively to assess the severity of GVHD and the status of the primary disease after BMT.

RESULTS

Eight donors had HTLP((f)) less than or equal to 10(-6); no recipients of these grafts developed severe GVHD after transplantation. Twenty-eight donors had HTLP(f) greater than 10(-6) and 18 recipients of these grafts developed severe GVHD (> or = grade 2) (chi(2) test, p<0.01). Seven donors had HTLP(f) greater than 10(-5) and no recipient had disease relapse. Twenty-nine donors had HTLP(f) less than or equal to 10(-5), 11 recipients of these grafts developed disease relapse (chi(2) test, p=0.08).

INTERPRETATION AND CONCLUSIONS

BMT recipients from HLA-identical sibling donors with low (<10(-6)) and high (>10(-5)) HTLP(f) may have a low risk of acute GVHD and disease relapse after transplantation.

Behavioral risk reduction in a declining HIV epidemic: injection drug users in New York City, 1990-1997

OBJECTIVES

This study assessed trends in HIV risk behaviors among injection drug users in New York City from 1990 to 1997.

METHODS

Injection drug users were recruited continuously from a large drug detoxification treatment program (N = 2588) and a research storefront located in a high-drug-use area (N = 2701). Informed consent was obtained, and a trained interviewer administered a structured interview covering sociodemographics, drug use history, HIV risk behavior, and participation in syringe exchange.

RESULTS

Trends were assessed for 5 risk behaviors in the 6-month period before the interview. The 3 injection risk behaviors declined significantly over time at each site (all P < .01). When data were pooled across sites, all 5 risk behaviors declined significantly over time (all P < .01). Participation in syringe exchange programs and in HIV counseling and testing increased greatly from 1990 to 1997.

CONCLUSIONS

The continuing risk reduction among injection drug users indicates a "declining phase" in the large HIV epidemic in New York City. HIV prevention programs appear to be making an important contribution to the declining phase.

Informal caring networks among Chinese elderly with disabilities in Hong Kong

Community care has been a major guiding policy in developing services for the elderly in Hong Kong. It has been assumed that Chinese families tend to have a large caring network to render care in the community. However, in a survey conducted in early 1991, it was found that such caring networks for disabled elderly people were very small and inconsequential. Quite a high proportion of Chinese disabled elderly are living alone in the community, and have a small network for emotional support. Effective measures to promote family care of disabled elderly people are discussed. Two pathways for integrating the formal and informal care sectors are examined in relation to promoting effective practice for the frail elderly living in the community.

Laboratory wear investigation of resin posterior denture teeth

This investigation compared the wear resistance of three "improved" resin posterior denture tooth formulations with two conventional products on a mechanical toothbrush abrasion machine. The ability of the teeth to resist this type of abrasion was evaluated by determination of the weight loss during 339 hours of brushing with firm nylon bristle toothbrushes. All brands exhibited negligible loss, with the conventional brands performing better than the "improved" formulations.

Inducible transformation of fibroblasts using a metallothionein-v-myc gene construct

An inducible oncogene construct has been engineered by coupling the MC29 v-myc oncogene to the sheep metallothionein promoter. Transfection of this plasmid, which also contains the neomycin resistance gene, into Rat-1 cells, has resulted in the isolation of independent clones resistant to G418. Certain of these clones were found to exhibit inducible transformation in response to ZnSO4. Transformation was graded with increasing ZnSO4 levels and was reversible when ZnSO4 was removed from the media. By analyzing v-myc mRNA levels, the inducible alterations in cellular morphology and growth were found to be associated with increased v-myc expression. The metallothionein promoter exhibited negligible constitutive expression of v-myc and none of the clones isolated exhibited spontaneous transformation. Our results show that the use of a metallothionein promoter v-myc construct facilitates the study of inducible fibroblast transformation.