A new pacemaker has been built inside a heart by converting beating muscle into cells which can organise the organ’s rhythm, US researchers report. The heartbeat is controlled by electrical signals and if these go awry the consequences can be fatal.

Scientists injected a genetically-modified virus into guinea pigs to turn part of their heart into a new, working pacemaker.

A human heart is made up of billions of cells, but researchers say fewer than 10,000 are responsible for controlling the heartbeat. Age and disease can lead to problems such as the heart pumping too fast or too slow – and it can even stop completely, in what is known as a cardiac arrest.

The solution is an implanted battery-powered pacemaker which will jolt the heart to keep it in line.

Instead a team of researchers at the Cedars-Sinai Heart Institute tried to restore the heart’s own ability to dictate the beat by creating new pacemaker cells. They used a virus to infect heart muscle cells with a gene, called Tbx18, which is normally active when pacemaker cells are formed during normal development in an embryo.

When heart cells were infected with the virus they became smaller, thin and tapered as they acquired the ‘distinctive features of pacemaker cells’, the report said.

Pacemakers are implanted into the chest to regulate the heartbeat When the virus was injected into a region of the hearts of seven guinea pigs, five later had heartbeats which originated from their new pacemaker.

One of the researchers Dr Hee Cheol Cho, from Cedars-Sinai, told that he expected the same method to work in the human heart as they used a human gene, Tbx18, to generate the effect. However, far more animal testing would be needed before the technique would ever be considered in people.

Dr Cho added: ‘Electronic devices are limited to their finite battery life, requiring battery changes. Complications such as displacement, breakage, entanglement of the leads are not uncommon and could be catastrophic, the incidence of devices with bacterial infection keeps going up and, for paediatric patients, the device does not ‘grow’ with the patients. All these problems could be solved by a biological pacemaker.’

Why does training in mindfulness meditation help patients manage chronic pain and depression? In a newly published neurophysiological review, Brown University scientists propose that mindfulness practitioners gain enhanced control over sensory cortical alpha rhythms that help regulate how the brain processes and filters sensations, including pain, and memories such as depressive cognitions.
The proposal, based on published experimental results and a validated computer simulation of neural networks, derives its mechanistic framework from the intimate connection in mindfulness between mind and body, since standardised mindfulness meditation training begins with a highly localised focus on body and breath sensations. This repeated localised sensory focus, the scientists write, enhances control over localised alpha rhythms in the primary somatosensory cortex where sensations from different body are ‘mapped’ by the brain.
In effect, what the researchers propose in their paper, is that by learning to control their focus on the present somatic moment, mindfulness meditators develop a more sensitive ‘volume knob’ for controlling spatially specific, localised sensory cortical alpha rhythms. Efficient modulation of cortical alpha rhythms in turn enables optimal filtering of sensory information. Meditators learn not only to control what specific body sensations they pay attention to, but also how to regulate attention so that it does not become biased toward negative physical sensations such as chronic pain. The localised attentional control of somatosensory alpha rhythms becomes generalised to better regulate bias toward internally focused negative thoughts, as in depression.
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For women with abdominal pain or vaginal bleeding during early pregnancy, patient history and clinical examination alone are insufficient to indicate or eliminate the possibility of ectopic pregnancy, while transvaginal sonography appears to be the single best diagnostic method for evaluating suspected ectopic pregnancy, according to an analysis of previous studies.
The rapid identification and accurate diagnosis of women who may have an ectopic pregnancy is critically important for reducing the maternal illness and death associated with this condition. Ectopic pregnancy is the leading cause of first-trimester pregnancy-related death, responsible for up to 6 percent of maternal mortality during early gestation, according to background information in the article. ‘Fewer than half of the women with an ectopic pregnancy have the classically described symptoms of abdominal pain and vaginal bleeding. In fact, these symptoms are more likely to indicate miscarriage.’
John R. Crochet, M.D., of the Center of Reproductive Medicine, Webster, Texas and colleagues conducted a study to systematically review the accuracy and precision of the patient history, clinical examination, readily available laboratory values, and sonography in the diagnosis of ectopic pregnancy in women with abdominal pain or vaginal bleeding during early pregnancy. The researchers conducted a search of the medical literature and identified 14 studies with 12,101 patients the met the criteria for inclusion in the analysis.
The authors found that presence of an adnexal (structures near the uterus, such as the ovaries and the Fallopian tubes) mass in the absence of an intrauterine pregnancy on transvaginal sonography, and the physical examination findings of cervical motion tenderness, an adnexal mass, and adnexal tenderness all increase the likelihood of ectopic pregnancy. ‘A lack of adnexal abnormalities on transvaginal sonography decreases the likelihood of ectopic pregnancy. Existing studies do not establish a single serum human chorionic gonadotropin [hCG; a hormone] level that is diagnostic of ectopic pregnancy.’
‘Women with abdominal pain or vaginal bleeding during early pregnancy may have an ectopic pregnancy. This systematic review of the literature and meta-analysis confirms that the patient history and clinical examination alone are insufficient to indicate or eliminate the possibility of ectopic pregnancy. In a hemodynamically stable patient, the appropriate evaluation includes transvaginal sonography and quantitative (serial) serum hCG testing. Patients with signs and symptoms of excessive blood loss or hemodynamic collapse should immediately have gynecological evaluation.’ EurekAlert

Replacing the combination of brand-name, antiretroviral drugs currently recommended for control of HIV infection with soon-to-be-available generic medications could save the U.S. health care system almost $1 billion a year but may diminish the effectiveness of HIV treatment.  A study led by Massachusetts General Hospital (MGH) investigators examines the potential impact of such a change.

"The switch from branded to generic antiretrovirals would place us in the uncomfortable position of trading some losses of both quality and quantity of life for a large potential dollar savings," says Rochelle Walensky, MD, MPH, of the MGH Medical Practice Evaluation Center, lead author of the study.  "By estimating the likely magnitude of these offsetting effects now