Inner ear tissue preservation by rapid freezing: improving fixation by high-pressure freezing and hybrid methods.

In the preservation of tissues in as 'close to life' state as possible, rapid freeze fixation has many benefits over conventional chemical fixation. One technique by which rapid freeze-fixation can be achieved, high pressure freezing (HPF), has been shown to enable ice crystal artefact-free freezing and tissue preservation to greater depths (more than 40 µm) than other quick-freezing methods. Despite increasingly becoming routine in electron microscopy, the use of HPF for the fixation of inner ear tissue has been limited. Assessment of the quality of preservation showed routine HPF techniques were suitable for preparation of inner ear tissues in a variety of species. Good preservation throughout the depth of sensory epithelia was achievable. Comparison to chemically fixed tissue indicated that fresh frozen preparations exhibited overall superior structural preservation of cells. However, HPF fixation caused characteristic artefacts in stereocilia that suggested poor quality freezing of the actin bundles. The hybrid technique of pre-fixation and high pressure freezing was shown to produce cellular preservation throughout the tissue, similar to that seen in HPF alone. Pre-fixation HPF produced consistent high quality preservation of stereociliary actin bundles. Optimising the preparation of samples with minimal artefact formation allows analysis of the links between ultrastructure and function in inner ear tissues.

Cochlear implantation in the mouse via the round window: effects of array insertion.

Animal models are the only means of assessing the effects of cochlear implantation (CI) at a cellular and molecular level. The range of naturally occurring and genetically-modified mouse strains which mimic human deafness provide excellent opportunities for auditory research. To date, there are very few studies of CI in mice. The main aims of this study were to develop a reproducible and viable technique to enable long term CI in the mouse and to assess the response of the mouse cochlea to implantation as a means of evaluating the success of the procedure. Electrode array implantation via the round window was performed in C57Bl/6 mice aged 3 and 6 months. The contralateral cochlea acted as a control. Auditory brainstem responses (ABR) were recorded prior to and following CI. Analysis showed greater threshold shifts in the implanted ear compared to the control ear post-implantation, but substantial preservation of hearing. There were no cases in which implantation caused a profound hearing loss across all frequencies. Cone beam computerised tomography and light microscopy confirmed correct placement of the electrode array within the scala tympani. Cochleae were prepared for histological examination. Initial analysis revealed encapsulation of the implant in tissue with morphological characteristics suggestive of fibrosis. Our results show that mouse CI via the round window offers a model for exploring tissue responses to implantation.

Costs and outcomes over 36 years of patients with phenylketonuria who do and do not remain on a phenylalanine-restricted diet.

BACKGROUND: To quantify the costs and consequences of managing phenylketonuria (PKU) in the UK and to estimate the potential implications to the UK's National Health Service (NHS) of keeping patients on a phenylalanine-restricted diet for life. METHOD: A computer-based model was constructed depicting the management of PKU patients over the first 36 years of their life, derived from patients suffering from this metabolic disorder in The Health Improvement Network database (a nationally representative database of patients registered with general practitioners in the UK). The model was used to estimate the incidence of co-morbidities and the levels of healthcare resource use and corresponding costs over the 36 years. RESULTS: Patients who remained on a phenylalanine-restricted diet accounted for 38% of the cohort. Forty-seven per cent of patients discontinued their phenylalanine-restricted diet between 15 and 25 years of age. Of these, 73% remained off diet and 27% restarted a restricted diet at a mean 30 years of age. Fifteen per cent of the cohort had untreated PKU. Eleven per cent of patients who remained on a phenylalanine-restricted diet for 36 years received the optimum amount of prescribed amino acid supplements. Patients had a mean 12 general practitioner visits per year and one hospital outpatient visit annually, but phenylalanine levels were only measured once every 18 to 24 months. The mean NHS cost (at 2007/08 prices) of managing a PKU sufferer over the first 36 years of their life was estimated to range between £21 000 and £149 000, depending on the amount of prescribed nutrition they received. CONCLUSION: The findings suggest that the majority of patients with PKU were under-treated. The NHS cost of patient management should not be an obstacle to encouraging patients to remain on a restricted diet until further information becomes available about the long-term clinical impact of stopping such a diet. Nevertheless, patients require counselling and managed follow up regardless of the choices they make about their diet.

Relative cost-effectiveness of a skin protectant in managing venous leg ulcers in the UK.

OBJECTIVE: To estimate the clinical and cost-effectiveness of using a skin protectant (Cavilon No Sting Barrier Film [NSBF] or Cavilon Durable Barrier Cream [DBC]; 3M) compared with not using a skin protectant in the management of venous leg ulcers (VLUs), in the UK. METHOD: A decision model was constructed depicting the patient pathways and associated management of a cohort of patients with and without a Cavilon formulation, plus dressings and compression. The model was based on the case records of a cohort of matched patients from The Health Improvement Network (THIN) database, who were first diagnosed with a VLU between 1 Jan 2008 and 31 Dec 2009. The model estimated the costs and outcomes of patient management over 6 months and the cost-effectiveness of using a Cavilon formulation relative to not using a skin protectant. RESULTS: Patients' mean age was 80.2 years and 61% were female. Sixty-five per cent (n=166) of Cavilon patients received NSBF, and 35% received DBC. Between 6% and 9% of VLUs were healed at 6 months and 53-66% became infected. Healing was affected by a patient's age (OR: 0.944 for each additional year), but not by gender, level of exudate or wound size. There was a significantly greater reduction in wound size among patients in the NSBF group than in the other two groups (p<0.001). Additionally, there was no significant difference in the initial wound size of those VLUs that did and did not heal in the two Cavilon groups; however, initial size of the VLUs that healed in the control group was significantly smaller than those that did not (p<0.001). Resource use was similar between the three groups. Patients were predominantly managed by practice nurses, with a mean 37-38 nurse visits over the study period. Patients' dressings were changed, on average, every 4-5 days, with a mean of 3 dressings under a compression bandage. The total 6-monthly NHS cost of managing a VLU was ~£2200. Practice nurse visits were the primary cost driver, accounting for up to 58% of the 6-monthly NHS cost, whereas dressings accounted for <10% of the cost. CONCLUSION: Use of NSBF leads to significantly greater wound size reduction than that observed in the other two groups and may facilitate the healing of larger wounds without increasing costs. Hence, use of NSBF for peri-wound skin protection in patients with exuding VLUs is the preferred treatment strategy. DECLARATION OF INTEREST: This study was sponsored by 3M Health Care, manufacturers of Cavillon NSBF and Cavillon DBC. However, the authors have no other conflicts of interest that are directly relevant to the content of this manuscript, which remains their sole responsibility.

Modelling the cost-effectiveness of electric stimulation therapy in non-healing venous leg ulcers.

OBJECTIVE: To estimate the cost-effectiveness of using electric stimulation (ES) therapy (Accel-Heal) plus dressings and compression bandaging compared with dressings and compression bandaging alone in treating chronic, non-healing venous leg ulcers (VLUs) of >6 months' duration from the perspective of the National Health Service (NHS) in the UK. METHOD: A 5-month Markov model was constructed, depicting the management of a chronic, non-healing VLU of >6 months' duration. The model considers the decision by a clinician to continue with a patient's previous care plan (comprising dressings and compression bandaging) or treating with ES therapy plus dressings and compression bandaging. The model was used to estimate the relative cost-effectiveness of ES therapy at 2008-2009 prices. RESULTS: According to the model, 38% of VLUs are expected to heal within 5 months after starting ES therapy, with a further 57% expected to improve. This improvement in clinical outcome is expected to lead to a 6% health gain of 0.017 QALYs (from 0.299 to 0.316 QALYs) over 5 months. The model also showed that using ES therapy instead of continuing with a patient's previous care plan is expected to reduce the NHS cost of managing them by 15%, from £880 to £749, due in part to a 27% reduction in the requirement for nurse visits (from mean 49.0 to 35.9 visits per patient) over the first 5 months after the start of treatment. Hence, use of ES therapy was found to be a dominant treatment (improved outcome for less cost). CONCLUSION: Within the model's limitations, use of ES therapy potentially affords the NHS a cost-effective treatment, compared with patients remaining on their previous care plan in managing chronic, non-healing VLUs of >6 months' duration. However, this is dependant on the number of ES therapy units per treatment, the unit cost of the device, and the number of nurse visits required to manage patients in clinical practice. DECLARATION OF INTEREST: This study was sponsored by Synapse Microcurrent Ltd., manufacturers of Accel-Heal. The authors have no other conflicts of interest that are directly relevant to the content of this manuscript. In particular, Synapse Microcurrent Ltd. had no role in the study design, in the collection, analysis and interpretation of data, or in writing the manuscript.

The cost-effectiveness of macrogol 3350 compared to lactulose in the treatment of adults suffering from chronic constipation in the UK.

BACKGROUND: It is unknown whether macrogol 3350 (Movicol) affords the UK's National Health Service (NHS) a cost-effective addition to the current range of laxatives. AIM: To estimate the cost-effectiveness of macrogol 3350 compared with lactulose in the treatment of chronic constipation, from the perspective of the UK's NHS. METHODS: A decision model depicting the management of chronic constipation was constructed using clinical outcomes and resource use values derived from patients suffering from chronic constipation in The Health Independent Network (THIN) database. The model was used to estimate the cost-effectiveness of a GP prescribing macrogol 3350 instead of lactulose to treat adults > or =18 years of age suffering from chronic constipation. RESULTS: Sixty-eight percent of patients given macrogol 3350 were successfully treated within 6 months after starting treatment compared to 60% of patients given lactulose.Patients' health status at 6 months was estimated to be 0.458 and 0.454 quality-adjusted life years (QALYs) in the macrogol 3350 and lactulose groups respectively. The total 6-monthly NHS cost of initially treating patients with macrogol 3350 or lactulose was estimated to be pound420 (US $688) and pound419 (US $686) respectively. Hence, the cost per QALY gained with macrogol 3350 was estimated to be pound250 (US $410). CONCLUSION: Macrogol 3350 affords the NHS a cost-effective addition to the range of laxatives available for this potentially resource-intensive condition.

Developmental analysis and computer modelling of bioengineered teeth.

Here we present the developmental progression of bioengineered pig teeth from 1 to 25 weeks of development. We demonstrate that 2-25 week implants contained embryonic tooth bud- and cap-stage tooth structures consisting of dental epithelium expressing the sonic hedgehog gene and condensed dental mesenchyme. Implants harvested at 18-25 weeks also contained tooth bud-like structures, as well as mature tooth structures containing enamel, dentin and pulp tissues. Immunohistochemical analyses confirmed the expression of dentin- and enamel-specific proteins in differentiated bioengineered tooth tissues. Three-dimensional computer modelling further demonstrated a spatial organization of enamel, dentin and pulp tissues resembling that of natural teeth. We conclude that bioengineered teeth commonly exhibit morphological stages characteristic of naturally forming teeth. Furthermore, the presence of immature tooth buds at all times assayed and increased numbers of bioengineered tooth structures over time suggests that porcine dental progenitor cells maintain the ability to form teeth for at least 25 weeks.

Efficacy of the latest fluoroquinolones against experimental Yersinia pestis.

The efficacies of prophylactic and therapeutic gatifloxacin and moxifloxacin were assessed in a BALB/c mouse model of systemic and pneumonic plague and compared with ciprofloxacin. Mice were given 100 mg/kg of the antibiotic by oral administration twice daily for 7 days starting 1h prior to infection or following infection. All antibiotics offered full protection for up to 6h following systemic challenge, and for up to 30 h following an aerosol challenge. The efficacy of each of the antibiotics decreased when antibiotics were started 18 h following systemic challenge and 48 h following aerosol challenge. Fluoroquinolones may therefore be considered useful candidates for the treatment of bubonic and pneumonic plague.

Symptom occurrence in persons with chronic fatigue syndrome.

This investigation compared differences in the occurrence of symptoms in participants with CFS, melancholic depression, and no fatigue (controls). The following Fukuda et al. [Ann. Intern. Med. 121 (1994) 953] criteria symptoms differentiated the CFS group from controls, but did not differentiate the melancholic depression group from controls: headaches, lymph node pain, sore throat, joint pain, and muscle pain. In addition, participants with CFS uniquely differed from controls in the occurrence of muscle weakness at multiple sites as well as in the occurrence of various cardiopulmonary, neurological, and other symptoms not currently included in the current case definition. Implications of these findings are discussed.

Sexual abuse, physical abuse, chronic fatigue, and chronic fatigue syndrome: a community-based study.

Using a randomly selected community-based sample, this investigation examined whether histories of childhood sexual, physical, and death threat abuse predicted adulthood outcomes of specific medical and psychiatric conditions involving chronic fatigue. This study also tested prior suggestions that most individuals with chronic fatigue syndrome report a past history of interpersonal abuse. Multinomial logistic regression was used to examine the relationship between abuse history and chronic fatigue group outcomes while controlling for the effects of sociodemographics. Compared with healthy controls, childhood sexual abuse was significantly more likely to be associated with outcomes of idiopathic chronic fatigue, chronic fatigue explained by a psychiatric condition, and chronic fatigue explained by a medical condition. None of the abuse history types were significant predictors of chronic fatigue syndrome. A closer examination of individuals in the chronic fatigue syndrome group revealed that significantly fewer individuals with CFS reported abuse as compared with those who did not. The implications of these findings are discussed.

Lack of evidence for association between endothelial nitric oxide synthase gene polymorphisms and coronary artery disease in the Australian Caucasian population.

BACKGROUND: Genetic polymorphism in the gene for endothelial nitric oxide synthase (eNOS) has been identified as a potential risk factor for the development of premature coronary artery disease (CAD). We determined whether the eNOS 4ab, G894T, and T-786C polymorphisms are associated with premature coronary artery disease. DESIGN: A case-control study. METHODS: PCR-based assays were used to compare the frequency of eNOS gene polymorphisms in 573 Caucasian subjects aged under 50 years presenting with symptomatic CAD and documented by coronary angiography, with or without myocardial infarction, to that of 624 similarly aged community controls without a history of symptomatic CAD. RESULTS: We found no difference in the frequency of 4ab genotypes between cases and controls: in the CAD subjects, the 4aa, 4ab, and 4bb genotype frequencies were 1.9%, 24.3% and 73.8% respectively, compared to 2.2%, 25.5% and 72.3% respectively for the controls. There was also no significant difference between cases and controls in the frequency of any allele (4a/4b, 894G/894T, -786C/-786T), or genotype for any of the polymorphisms. Similarly, logistic regression analysis showed no evidence for an association of the polymorphisms with premature CAD or myocardial infarction or any indication of an interaction between the polymorphisms and other CAD risk factors, including smoking. CONCLUSIONS: In a large case-control study, and in contrast to some earlier positive findings by others, we have found no evidence for an association between several eNOS gene polymorphisms and premature CAD in an Australian Caucasian population.

Improved analysis of brachial artery ultrasound using a novel edge-detection software system.

Brachial artery ultrasound is commonly employed for noninvasive assessment of endothelial function. However, analysis is observer dependent and susceptible to errors. We describe studies on a computerized edge-detection and wall-tracking software program to allow more accurate and reproducible measurement. In study 1, three purpose-built Perspex phantom arteries, 3.00, 4.00, and 6.00 mm in diameter, were measured with the software. There was a mean bias of 11 microm (P < 0.001 at each level) between known and measured values; the mean resolving power of the software was estimated as 8.3 microm. In study 2, the mean intraobserver coefficient of variation of repeated measures of flow-mediated dilation (FMD) using the software (6.7%) was significantly lower than that for traditional manual measurements using the intima-lumen interfaces (24.8%, P < 0.05) and intima-media interfaces (32.5%, P < 0.05). In study 3, 24 healthy volunteers underwent repeat testing twice within 1 wk; the coefficients of variation for between-visit reproducibility of FMD and response to glyceryl trinitrate using the software were 14.7 and 17.6%, respectively. Assuming 80% power and an alpha of 0.05, eight subjects with matched controls would be required, in a parallel designed study, to detect an absolute 2.5% change in FMD. In summary, we have developed a semiautomated computerized vascular ultrasound analysis system that will improve the power of clinical intervention studies to detect small changes in arterial diameter.

A community-based study of seasonal variation in the onset of chronic fatigue syndrome and idiopathic chronic fatigue.

One proposed hypothesis regarding the etiology of chronic fatigue syndrome (CFS) is that there is a subgroup of patients in which symptom onset is precipitated by a viral infection. If this is indeed true, then one would anticipate a greater incidence of the emergence of CFS symptoms during months when viral infections occur with the greatest frequency. The current community-based epidemiology study examined the month of symptom onset for 31 patients with CFS and 44 others with idiopathic chronic fatigue (ICF). It was determined that the distribution of the month of illness onset for the CFS and ICF groups was nonrandom, with greater numbers of participants than expected reporting an onset of CFS and ICF during January.

Equal care ensures equal survival for African-American women with cervical carcinoma.

BACKGROUND: [corrected] It was the purpose of this study to investigate whether race is an independent prognostic factor in the survival of patients with cervical carcinoma in a health care system with minimal racial bias, and few barriers to access to care. METHODS: Records for patients with a diagnosis of invasive cervical carcinoma from 1988 to 1999 were obtained from the Automated Central Tumor Registry for the United States Military Health Care System. Clinical data including race, age at diagnosis, histology, grade, stage, socioeconomic status, treatment modality, and survival also were obtained. Survival analysis was performed with Kaplan-Meier survival curves. RESULTS: One thousand five hundred fifty-three patients were obtained for review. Sixty-five percent of patients were Caucasian, and 35% were minorities. Of the minorities, 29% were African Americans (AAs). Mean age of diagnosis was similar among AAs and Caucasians, 44 and 42 years, respectively. There was no statistically significant difference between the distribution of age, stage, grade, or histology between Caucasians and AAs. Forty-six percent of patients were treated with surgery and 56% with radiation therapy, with no difference in type of treatment between the Caucasian and AA groups. Five- and 10-year survival rates for Caucasians and AAs were 75%, and 76%, and 64% 65% (P = 0.59), respectively. CONCLUSIONS: In an equal access, unbiased, nonracial environment, race is not an independent predictor of survival for patients with cervical carcinoma. This study has shown, for the first time to the authors' knowledge, that when they receive equal treatment for cervical carcinoma, AA women's survival can approach that of their nonminority counterparts (75% at 10 years).

Assessing attitudes toward new names for chronic fatigue syndrome.

A questionnaire was distributed at the American Association of Chronic Fatigue Syndrome's biannual convention in Washington in January 2001 as well as through various Internet Web sites and listserves during early February and March of 2001. The sample consisted of 432 respondents. Most respondents (86%) indicated they wanted a name change, although more patients than scientists were in favor of this change. It was also apparent that the patients and physicians were clearly split between adopting a name such as myalgic encephalopathy versus one such as neuro-endocrine immune disorder. Also, among those respondents who selected either of these two choices for a new name, less than 30% of them supported the other name. Although the majority of respondents feel the name should be changed at this time, this survey suggests there are different stakeholders involved in the name-change process, each with strong and sometimes disparate feelings about changing the name.

Attitudes regarding chronic fatigue syndrome: the importance of a name.

Undergraduates from diverse academic backgrounds and medical trainees were assessed regarding their attitudes about and familiarity with chronic fatigue syndrome (CFS). We explored whether different names given to chronic fatigue syndrome (CFS, myalgic encephalopathy, or Florence Nightingale disease) were associated with differences in attributions regarding its cause, nature, severity, contagion, prognosis, and treatment. Participants' attributions toward the illness varied with the names used to characterize it. Participants prompted with the myalgic encephalopathy name were more likely to attribute a biomedical cause to the illness, and less likely to consider patients as candidates for organ donation than those prompted with the CFS name. Although the medical trainees were less likely to consider the patient as malingering, and more likely to view the illness as leading to poorer quality of life and a poorer prognosis, they were also more likely to consider the illness a form of primary depression, more likely to think the patient would attempt suicide, and less likely to consider associated cognitive symptoms as severe. The implications are discussed.

Feminist perspectives on the social construction of chronic fatigue syndrome.

We contrast Western medical views of chronic fatigue syndrome (CFS) etiology, diagnosis, and treatment with views maintained by a predominantly female CFS population. We argue that the failure of Western medicine to demonstrate a viral etiology for CFS led to a paradigmatic shift in research perspectives, which then embraced psychiatric and sociocultural explanations for CFS. As a result, CFS was delegitimized as a biomedical phenomenon within medical, academic, governmental, and public arenas. We compare alternative social constructions of CFS with issues pertaining to multiple sclerosis (MS), an illness that similarly predominates among women. Patient perspectives suggest that the history of medical attitudes toward CFS may eventually parallel the transformations that occurred in relation to MS. In particular, the discovery of biological markers for CFS may lay to rest the categorization of CFS as largely within the psychiatric realm.

Chronic fatigue syndrome: sociodemographic subtypes in a community-based sample.

Most chronic fatigue syndrome (CFS) studies are based on information about patients from primary or tertiary care settings. These patients might not be typical of patients in the general population. This investigation involved examinations of individuals with CFS from a community-based study. A random sample of 18,675 in Chicago was interviewed by telephone. Individuals with chronic fatigue and at least four minor symptoms associated with CFS were given medical and psychiatric examinations. A group of physicians then diagnosed individuals with CFS, who were then subclassified based on three sociodemographic categories--gender, ethnicity, and work status. Sociodemographic subgroups were analyzed in terms of symptom severity, functional disability, coping, optimism, perceived stress, and psychiatric comorbidity. Women, minorities, and nonworking individuals with CFS reported greater levels of functional disability, symptom severity, and poorer psychosocial functioning than men, Caucasians, and working individuals, suggesting sociodemographic characteristics may be associated with poorer outcomes in urban, community-based samples of CFS individuals.

Chronic fatigue syndrome, fibromyalgia, and multiple chemical sensitivities in a community-based sample of persons with chronic fatigue syndrome-like symptoms.

OBJECTIVE: The aim of this study was to determine illness comorbidity rates for individuals with chronic fatigue syndrome (CFS), fibromyalgia (FM), and multiple chemical sensitivities (MCS). An additional objective was to identify characteristics related to the severity of fatigue, disability, and psychiatric comorbidity in each of these illness groups. METHODS: A random sample of 18,675 residents in Chicago, Illinois, was first interviewed by telephone. A control group and a group of individuals with chronic fatigue accompanied by at least four minor symptoms associated with CFS received medical and psychiatric examinations. RESULTS: Of the 32 individuals with CFS, 40.6% met criteria for MCS and 15.6% met criteria for FM. Individuals with MCS or more than one diagnosis reported more physical fatigue than those with no diagnosis. Individuals with more than one diagnosis also reported greater mental fatigue and were less likely to be working than those with no diagnosis. Individuals with CFS, MCS, FM, or more than one diagnosis reported greater disability than those with no diagnosis. CONCLUSIONS: Rates of coexisting disorders were lower than those reported in prior studies. Discrepancies may be in part attributable to differences in sampling procedures. People with CFS, MCS, or FM endure significant disability in terms of physical, occupational, and social functioning, and those with more than one of these diagnoses also report greater severity of physical and mental fatigue. The findings illustrate differences among the illness groups in the range of functional impairment experienced.