19 July, 2008
15 July, 2008
Study at Bonn University Clinic suggests delaying operations till the next day
Kidney transplants should be carried out during the day if possible. At least this is the conclusion suggested by a survey just published by urologists and internists at the University of Bonn (Transplantation Proceedings, vol. 40, p. 1341 ff.). Hence operations carried out at night require a further operation more than twice as often as other operations. Moreover, the risk of premature failure of the transplant is higher with operations taking place at night. The reason is probably that the surgeon is more alert and focused during the day. Particularly with a complicated procedure such as a transplant, surgical skill is a critical factor for success. Still, currently every third kidney transplant is performed at night, as donor organs should be as fresh as possible.
The medics from Dr. Guido Fechner and Professor Stefan Müller's Bonn team scrutinised a total of 260 kidney transplants. Over 60 per cent had been carried out during the day, the remainder between eight in the evening and eight o'clock in the morning. More than 16 per cent of all the 'night kidneys' had to be operated on a second time in the month following the transplant due to surgical complications. With the 'day kidneys', the complications rate was significantly less, being over six per cent.
On average transplanted kidneys last nine years, but there are also transplants that still work well after more than 20 years. The time when the operation took place here too seems to be a critical factor. 'For "day kidneys" there is a higher than 90 per cent chance that they will function flawlessly even five years after the transplant,' Dr. Guido Fechner explains. 'With "night kidneys" the figure is only 80 per cent.'
The reason presumed for this is that kidney transplants are comparatively complicated procedures. Accordingly, they require a brain that is alert. However, the donated organs are often transplanted during the night shift. 'It was long believed that kidneys had to be as fresh as possible, at all cost, for the transplant to be successful,' Guido Fechner says. It is currently perceived as ideal if the organ is reinserted 18 hours after its removal at the latest. 'Rescheduling a kidney transplant within this time frame, say from 5 a.m. to 8 a.m., without the transplant suffering, is definitely feasible,' he emphasises. 'Instead operations are performed as early as possible, even if that means the urologist has to work at night.'An alternative is a living kidney donation during which the kidney is taken from a living donor and is immediately inserted into the recipicent. This always happens during the day
06 July, 2008
The emotional well-being of families where children lack a genetic or gestational link to one or both of their parents � where the children have been conceived through surrogacy, egg donation or donor insemination � has long been a subject of debate. Now, in the first worldwide study of this issue, British scientists have shown that relationships within such families appear to be functioning well, and that there are few differences between them and families in whom children were conceived naturally.
Miss Polly Casey, from the Centre for Family Research, Cambridge University, UK, will tell the 24th annual conference of the European Society of Human Reproduction and Embryology this week that the study found that the egg donation, surrogacy, and donor insemination families showed more similarities than differences in the psychological well-being of the parents, the quality of parent-child relationships, and the psychological adjustment of the child. The potential negative consequences for such children have long been the subject of debate, with concern that parents may behave less positively towards them, and that the child may not feel fully accepted as part of the family.
The researchers have been following up 39 surrogacy families, 43 donor insemination families, 46 egg donation families, and 70 families where children had been conceived naturally. So far the data have been collected up to the time that the children are seven years old, but the researchers hope to continue following up these families for as long as possible. The findings to be presented are from approximately half of the families where the child has reached seven years old.
"We asked questions in a number of different areas to both parents and children," said Miss Casey. "We looked at such things as parental psychological wellbeing and parent-child relationships, and also questioned the mothers on any emotional and behavioural problems they felt that the child might have." In addition, researchers used the standardised Strengths and Difficulties Questionnaire, which produces an overall score of the child's adjustment along with individual scores for such things as conduct problems and emotional difficulties. Teachers completed the same questionnaire providing an independent assessment of children's adjustment.
The children's perception of the emotional closeness to their parents was also assessed. "We gave them a blank 'map' with concentric circles and told them that they were at the centre," said Miss Casey. "We then asked them to complete the map by placing family members and friends in the circle that represented the emotional closeness of each relationship."
A pictorial scale of perceived competence and social acceptance was also administered to the children. Pictures of children in different situations were presented by the researcher, against which the children were asked to evaluate themselves. This provided a measure of their cognitive competence, physical competence, maternal acceptance, and acceptance by their peers, all of which have been shown to be associated with the development of self-esteem in later childhood.
"We found that the family types did not differ in the overall quality of the relationship between mothers and their children and fathers and their children," said Miss Casey. "But the analysis did show some differences in the mother-child relationship between family types. For example, we found a minor trend towards greater sensitivity to their child's anxieties and worries among the egg donation and surrogacy mothers compared with the donor insemination mothers, and there was a minor trend towards greater emotional over-involvement with their children, and towards greater disciplinary indulgence, by assisted reproduction mothers as opposed to natural conception mothers."
The children in the different family types did not differ with respect to the Strengths and Difficulties Questionnaire as completed by their mothers. However, when the teachers completed the same exercise, a significant difference emerged. "The teachers reported a higher level of emotional difficulties among the assisted reproduction as opposed to the naturally conceived children, although these were not abnormally high," said Miss Casey.
The children's own assessments showed no significant difference between family types for self-esteem. In assessments of family relationships, there was no significant difference between the assisted reproduction children and the naturally conceived children in the location of their mother or father in the family maps, with 85% of assisted reproduction children and 88% of those naturally conceived placing their mother in the closest circle, and 73% of assisted reproduction and 76% of naturally conceived children placing their father in the closest circle.
"However," said Miss Casey "at the time of the child's seventh birthday, only 39% of egg donation parents, 29% of donor insemination parents, and 89% of surrogacy parents had told their children about the nature of their conception. This is markedly less than the proportion of parents who, when their child was one year old, reported that they planned to disclose this information � 56%, 46% and 100% of egg donation, donor insemination and surrogacy parents respectively," she said.
There are numerous and complex reasons for parents deciding not to inform children, the researchers say, including a desire to protect the father, since the mother may not want others to know about his infertility, and the fear that a child may feel less love for the non-genetic parent. "Previous studies have shown that parents want to protect their child, fearing that disclosure may upset them and have an adverse effect on parent-child relationships," said Miss Casey.
Analysis of the differences in the quality of parent-child relationships and the psychological adjustment of the child found significant disparities between those families who had disclosed information regarding conception, and those who had not. "Those mothers who had told their children about their conception showed higher levels of sensitivity to the child and, although there was no statistical difference, we also found that fathers in disclosing families tended to show greater warmth towards their children," said Miss Casey.
Mothers who had been open with children also reported greater marital satisfaction. The researchers also reported a non-significant trend towards lower levels of emotional difficulties among the children who had been told, as assessed by teachers.
"This study shows that families with children without a genetic or gestational link between the parents continue to function well as the child reaches early school years," said Miss Casey. "Where differences in mother-child relationship were found between the different family types, these were reflected in more involved parenting by the assisted reproduction mothers. Those who lacked a genetic or gestational relationship with their child � the egg donation and surrogacy mothers � tended towards greater involvement, as opposed to the donor insemination mothers. These findings are not surprising given the difficulties that the women underwent in achieving motherhood.
"The children themselves showed positive psychological adjustment and did not differ as to family type. We were particularly interested to find that, according to teachers, those children who had been told of their origins tended to do slightly better emotionally than those who had not, though of course this may simply be due to better communication within the family generally. We believe that our findings will benefit clinicians who counsel prospective parents about the implications of disclosing the means of conception to their child, as well as to parents, and, indeed, children, who will be able to learn from the experience of others in similar situations. It is essential that all developments in assisted reproduction are accompanied by studies of the wellbeing of the parents and children involved," said Miss Casey.
01 July, 2008
Researchers have discovered a molecular mechanism in a strain of rats that explains why metabolic disorders like hypertension and diabetes often arise together in mammals. The University of California, San Diego’s Jacobs School of Engineering also showed that a common antibiotic reversed the animals’ symptoms of high blood pressure, insulin resistance, and immune suppression.
These studies indicate that hypertension and cell dysfunctions associated with metabolic syndrome may be part of an enzymatic auto-digestion process in which proteases in our body become uncontrolled and break down proteins, reports Geert Schmid-Schnbein, a professor of bioengineering.
Spontaneously hypertensive rats (SHR), a strain predisposed to develop high blood pressure, were used in the study. These rodents, like many people, develop other metabolic complications when high blood pressure arises.
The investigators found significant levels of proteases in the animals’ circulation. Natural enzyme inhibitors found in normal healthy rats did not lower the level of protease activity in the SHR strain to normal levels.
In these hypertensive rat, enzymes cleaved extracellular portions of several protein receptors such as the insulin receptor. Insulin could thus no longer bind and facilitate normal metabolism of glucose, the scientists report. The CD18 receptor, a binding receptor on the surface of infection-fighting leukocytes, was also cleaved. With the loss of CD18 receptors, leukocytes of the SHR animals were unable to bind to the wall of blood vessels, resulting in a compromised immune system, according to the researchers.
The team went on to test whether a protease-blocking drug doxycycline could reverse the multiple metabolic complications. They found that the compound halted the activity of certain proteases in the SHR rat strain.
The scientists had observed that protein receptors on the surface of SHR cells become clipped off as the animals develop hypertension. They found that after several weeks of ingesting doxycycline, however, the SHR rats developed cells that had normal CD18 and insulin receptors. The animals’ metabolic conditions simultaneously improved, blood pressure normalized, and symptoms of immune suppression disappeared, they report.
The study is published on June 30 in the online version of Hypertension.