Lysine demethylases KDM6A and UTY: the X and Y of histone demethylation

Histone demethylases remove transcriptional repressive marks from histones in the nucleus. KDM6A (also known as UTX) is a lysine demethylase which acts on the trimethylated lysine at position 27 in histone 3. The KDM6A gene is located on the X chromosome but escapes X inactivation even though it is not located in the pseudoautosomal region. There is a homologue of KDM6A on the Y chromosome, known as UTY. UTY was thought to have lost its demethylase activity and to represent a non-functional remnant of the ancestral KDM6A gene. However, results with knockout mice suggest that the gene is expressed and the protein performs some function within the cell. Female mice with homozygous deletion of Kdm6a do not survive, but hemizygous males are viable, attributed to the presence of the Uty gene. KDM6A is mutated in the human condition Kabuki syndrome type 2 (OMIM 300867) and in many cases of cancer. The amino acid sequence of KDM6A has been conserved across animal phyla, although it is only found on the X chromosome in eutherian mammals. In this review, we reanalyse existing data from various sources (protein sequence comparison, evolutionary genetics, transcription factor binding and gene expression analysis) to determine the function, expression and evolution of KDM6A and UTY and show that UTY has a functional role similar to KDM6A in metabolism and development

Observations by a statistical watchdog

During more than five decades, the author has kept a critical eye on how statistical methods are (mis-) used in medical research. Some areas are presented where serious statistical mistakes are prevalent. Two investigations with erroneous conclusions are described in detail. Situations where outside authorities have tried to mute medical researchers are also commented upon. The authors own efforts to improve the use of statistical methods and the current situation with easily accessible statistical program packages are described. Finally, the importance of continued 'statistical cleansing' is stressed

Self-reported symptom distress in cancer patients: Reflections of disease, illness or sickness?

This article examines the relationships between symptom distress in a heterogeneous group of cancer patients and a number of possible explanatory variables, categorized as demographic, medical/clinical, individual/psychosocial and variables related to patients' views of care provided by the health care system. A series of explorative multiple regression analyses were undertaken to this end. The data are derived from a cross-sectional study of cancer patients diagnosed in 1987 at one general hospital in the greater Stockholm area, using semi-structured interviews in conjunction with McCorkle and Young's Symptom Distress Scale, Antonovsky's Sense of Coherence Questionnaire, Cutrona and Russell's Social Provisions Scale and Smilkstein's Family APGAR. Symptom distress is studied as a cumulative index, as well as in terms of the sub-indexes of pain, appetite/nausea, functional aspects, psychological aspects and social aspects. When the four categories of explanatory variables are combined, considerably higher levels of variance are explained for all 6 indexes of the Symptom Distress Scale, than when the regression analyses are performed separately with each distinct category of explanatory variables. This provides a statistical illustration of the multifaceted and complex nature of symptom distress. The data are presented in the context of a conceptual discussion about the meaning of symptoms. Symptom distress, in this study, appears to reflect both personal and cultural experiences, that is 'illness' and 'sickness' processes, rather than primarily medical/clinical variables, or 'disease'. Antonovsky's salutogenic model is suggested as a fruitful framework for further analysis.symptom distress psychosocial oncology cancer nursing salutogenic model sense of coherence medical anthropology

Symptoms and signs possibly indicating segmental, discogenic pain : A fusion study with 18 years of follow-up

BACKGROUND: Only two out of the five existing randomized studies have reported better results from fusion surgery for chronic low back pain (CLBP) compared to conservative treatment. In these studies the back symptoms of the patients were described simply as "chronic low back pain". One possible reason for the modest results of surgery is the lack of a description of specified symptoms that might be related to a painful segment/disc, and patient selection may therefore be more or less a matter of chance. Previous prospective studies including facet joint injections and discography and eventually MRI have failed to identify patients with a painful segment/disc that will benefit from fusion surgery. PURPOSE: Our purpose was to analyse in detail the pre-operative symptoms and signs presented by patients who showed substantial relief from their back pain following spinal fusion surgery with the aim of possibly finding a pain pattern indicating segmental, discogenic pain. METHODS: We analysed 40 consecutive patients, mean age 41 years, with a history of disabling low back pain for a mean of 7.7 years. Before surgery the patients completed a detailed questionnaire concerning various aspects of their back pain, and findings at clinical examination were thoroughly noted. Monosegmental posterior lumbar interbody fusion without internal fixation was performed using microsurgical technique. Outcome was assessed at 1, 2 and 4 years after surgery and finally at 18 years, using self-reporting measures and assessment by an independent examiner. Assessment at 18 years applied the Balanced Inventory for Spinal Disorders Questionnaire and the Roland-Morris Disability Questionnaire. RESULTS: According to the independent observer's assessment at two years 27 of the 40 patients were much improved. Analysis of the pre-operative depiction of the back symptoms of this group revealed a rather uniform pattern, the most important being: dominating back pain originating in the midline of the spine, with a dull, aching character and stabbing pain in the same area provoked by sudden movements. Most patients in this group also had diffuse pain radiation of various extension down one or both legs and often bladder dysfunction with frequency. At clinical examination, localized interspinal tenderness was observed within the spinal area in question and the patient's back pain was provoked by pressure in that area and by tapping a neighbouring spinous process. At 18 years after surgery 19 patients assessed themselves as much improved. At that time 5 of them had pension due to age, 7 early pension, one worked full time and six patients part time. Eleven patients were re-operated due to defect bony healing. CONCLUSIONS: The results may suggest that the use of a detailed symptom analysis and clinical examination may make it possible to select a subgroup of patients within the CLBP group likely to have better outcome following fusion surgery. IMPLICATIONS: The next step would be to execute prospective studies and if our findings concerning back pain details and signs among CLPB patients can be confirmed this can provide for more accurate selection of patients suitable for fusion surgery

A small group Whiplash-Associated-Disorders (WAD) patients with central neck pain and movement induced stabbing pain, the painful segment determined by mechanical provocation : Fusion surgery was superior to multimodal rehabilitation in a randomized trial

Background The majority of patients suffering from a whiplash injury will recover, but some will have symptoms (Whiplash Associated Disorders, WAD) for years despite conservative treatment. Some of these patients perceive neck pain that might come from a motion segment, possibly the disc. In comprehensive reviews no evidence has been found that fusion operations have a positive treatment effect on neck pain in WAD patients. Purpose Our aim was to evaluate the possibility of (a) selecting a subgroup of chronic WAD patients based on specified symptoms possibly indicating segmental pain, and (b) treating said segmental pain through fusion operation based on non-radiological segment localization. The hypothesis was that fusion operation in this selected subgroup of chronic WAD patients could alleviate perceived neck pain. Methods Eligible patients for the study had a traffic accident as the origin for their neck pain, and no previous neck symptoms. Neck pain should be the predominant symptom and the pain origin reported to be in the midline, being dull, aching in character and at sudden movements combined by a stabbing pain in the same area. Forty-nine patients with these specified symptoms were identified among a large number of chronic WAD patients. Those selected had pronounced symptoms for a median of around 50 months and had previously been investigated and fully treated within the ordinary healthcare system without success. No neurological abnormalities were to be found at clinical examination and no specific changes to be seen on X-ray and MRI. The patients were randomized to either cervical fusion operation or multimodal rehabilitation. By using a mechanical provocation test the level/s to be fused were identified. In all but one patient the surgery was performed anteriorly using microsurgical technique and a right-sided Smith-Pedersen approach and plate fixation. The multimodal rehabilitation at the Clinic of Medical Rehabilitation, Karolinska Hospital, Stockholm, included outpatient treatment for four days a week for six weeks and included treatment by physician, physiotherapists, occupational therapist, psychologists, social-service worker and nurses. Perceived change in neck pain was assessed using the Balanced Inventory for Spinal Disorders questionnaire at the 2-year-follow-up. Results Mean age of the patients was 38 and 40 years (surgery and rehabilitation groups, respectively), the most common type of accident being rear-end collision. At clinical examination muscle tenderness was not an outstanding sign. In most patients the mid-cervical region appeared to be the painful area but one patient localized the pain to C1. At follow-up 67% of the patients in the surgery group and 23% in the rehabilitation group assessed improvements in the ITT analysis. Corresponding proportions in the per protocol analysis were 83% and 12%, respectively. Conclusions The results support the supposition that among patients with central neck pain for long periods of time following a whiplash injury there are some in whom the neck pain emanates from a motion segment, probably the disc, a situation suitable for fusion surgery. Implications Thorough individual symptom evaluation in patients with chronic WAD may identify patients who will benefit from cervical fusion surgery