Printing body part using 3D bio-printer sounds like sci-fi coming to reality. It can print tissues now, but sooner or later, they can print a whole limb with bones and tissue. Maybe we can even print a complete human and use the 3D bio-printer as a cloning machine.

Feb 18th 2010, The Economist
A machine that prints organs is coming to market

THE great hope of transplant surgeons is that they will, one day, be able to order replacement body parts on demand. At the moment, a patient may wait months, sometimes years, for an organ from a suitable donor. During that time his condition may worsen. He may even die. The ability to make organs as they are needed would not only relieve suffering but also save lives. And that possibility may be closer with the arrival of the first commercial 3D bio-printer for manufacturing human tissue and organs.

The new machine, which costs around $200,000, has been developed by Organovo, a company in San Diego that specialises in regenerative medicine, and Invetech, an engineering and automation firm in Melbourne, Australia. One of Organovo’s founders, Gabor Forgacs of the University of Missouri, developed the prototype on which the new 3D bio-printer is based. The first production models will soon be delivered to research groups which, like Dr Forgacs’s, are studying ways to produce tissue and organs for repair and replacement. At present much of this work is done by hand or by adapting existing instruments and devices.

To start with, only simple tissues, such as skin, muscle and short stretches of blood vessels, will be made, says Keith Murphy, Organovo’s chief executive, and these will be for research purposes. Mr Murphy says, however, that the company expects that within five years, once clinical trials are complete, the printers will produce blood vessels for use as grafts in bypass surgery. With more research it should be possible to produce bigger, more complex body parts. Because the machines have the ability to make branched tubes, the technology could, for example, be used to create the networks of blood vessels needed to sustain larger printed organs, like kidneys, livers and hearts.
Printing history

Organovo’s 3D bio-printer works in a similar way to some rapid-prototyping machines used in industry to make parts and mechanically functioning models. These work like inkjet printers, but with a third dimension. Such printers deposit droplets of polymer which fuse together to form a structure. With each pass of the printing heads, the base on which the object is being made moves down a notch. In this way, little by little, the object takes shape. Voids in the structure and complex shapes are supported by printing a “scaffold” of water-soluble material. Once the object is complete, the scaffold is washed away.

Researchers have found that something similar can be done with biological materials. When small clusters of cells are placed next to each other they flow together, fuse and organise themselves. Various techniques are being explored to condition the cells to mature into functioning body parts—for example, “exercising” incipient muscles using small machines.

Though printing organs is new, growing them from scratch on scaffolds has already been done successfully. In 2006 Anthony Atala and his colleagues at the Wake Forest Institute for Regenerative Medicine in North Carolina made new bladders for seven patients. These are still working.

Dr Atala’s process starts by taking a tiny sample of tissue from the patient’s own bladder (so that the organ that is grown from it will not be rejected by his immune system). From this he extracts precursor cells that can go on to form the muscle on the outside of the bladder and the specialised cells within it. When more of these cells have been cultured in the laboratory, they are painted onto a biodegradable bladder-shaped scaffold which is warmed to body temperature. The cells then mature and multiply. Six to eight weeks later, the bladder is ready to be put into the patient.

The advantage of using a bioprinter is that it eliminates the need for a scaffold, so Dr Atala, too, is experimenting with inkjet technology. The Organovo machine uses stem cells extracted from adult bone marrow and fat as the precursors. These cells can be coaxed into differentiating into many other types of cells by the application of appropriate growth factors. The cells are formed into droplets 100-500 microns in diameter and containing 10,000-30,000 cells each. The droplets retain their shape well and pass easily through the inkjet printing process.

A second printing head is used to deposit scaffolding—a sugar-based hydrogel. This does not interfere with the cells or stick to them. Once the printing is complete, the structure is left for a day or two, to allow the droplets to fuse together. For tubular structures, such as blood vessels, the hydrogel is printed in the centre and around the outside of the ring of each cross-section before the cells are added. When the part has matured, the hydrogel is peeled away from the outside and pulled from the centre like a piece of string.

The bio-printers are also capable of using other types of cells and support materials. They could be employed, Mr Murphy suggests, to place liver cells on a pre-built, liver-shaped scaffold or to form layers of lining and connective tissue that would grow into a tooth. The printer fits inside a standard laboratory biosafety cabinet, for sterile operation. Invetech has developed a laser-based calibration system to ensure that both print heads deposit their materials accurately, and a computer-graphics system allows cross-sections of body parts to be designed.

Some researchers think machines like this may one day be capable of printing tissues and organs directly into the body. Indeed, Dr Atala is working on one that would scan the contours of the part of a body where a skin graft was needed and then print skin onto it. As for bigger body parts, Dr Forgacs thinks they may take many different forms, at least initially. A man-made biological substitute for a kidney, for instance, need not look like a real one or contain all its features in order to clean waste products from the bloodstream. Those waiting for transplants are unlikely to worry too much about what replacement body parts look like, so long as they work and make them better.

Should I swallow some hookworms to cure my allergies and asthma?

26 September 2009 – BBC News
Hookworms have infected humans for thousands of years

Parasitic gut worms, such as hookworm, might aid the development of new treatments for asthma and other allergies, a study in Vietnam suggests.

Infection with hookworm and other parasitic worms is endemic in Vietnam, but rates of asthma and other allergies are low.

British and Vietnamese scientists gave local children treatment to clear their body of worms.

They found this led to an increase in dust mite allergy among the children.

The next step is to understand exactly how and when gut parasites programme the human immune system
Dr Carsten Flohr
University of Nottingham

Thanks to improved hygiene, practices parasitic worms have been mostly eradicated among human populations living in developed countries.

However, experts believe that over millions of years of co-evolution worms have found methods to dampen down host immune responses to prolong their own survival inside humans.

This relationship seems to have become so intertwined that without gut worms or other parasites, our immune system can become unbalanced, which, in turn, could contribute to the development of asthma and other allergies.

The latest study was conducted in a rural area of central Vietnam where two in every three children have hookworm and other gut parasite infections, and where allergies are extremely rare.

More than 1,500 schoolchildren aged six to 17 took part.

Some of the children were given repeated tablet treatments to clear their body of gut worms.

The treatment did not produce any conclusive effect on rates of asthma or eczema.

However, those children who received the tablets did have a significantly increased risk of developing allergies to the house-dust mite.

Up to 80% of people with asthma also have allergies to house-dust mites and other environmental allergens.

The researchers said this strongly suggests that gut worms have the potential to tone down human immune responses.

Researcher Dr Carsten Flohr, of the University of Nottingham, said: “The next step is to understand exactly how and when gut parasites programme the human immune system in a way that protects against allergies, and for such studies, follow-up from birth will be essential.”

The hope is that the work could aid the development of new treatments which work in the same way as gut parasites, by dampening down or rebalancing the immune system so that the body does not respond to allergens and trigger asthma attacks.

Dr Elaine Vickers, Research Relations Manager at the charity Asthma UK, which funded the research, said: “The prospects of further studies in this area are very exciting as we could see groundbreaking treatments for asthma and other allergies developed as a result.”

I suffers from both eczema and asthma. It would be a good news if the scientists find a cure to both of them.

Breathe easy

May 21st 2009
From The Economist print edition
Researchers discover how a skin disease may trigger a lung complaint

ONE of the prices humanity seems to pay for getting richer is the rise of asthma. This life-threatening, allergy-driven lung disease is common in wealthy countries, absent from poor ones and on the rise in those making the transition. But exactly what causes it is unknown.

A number of explanations have been proposed. These range from the idea that clean modern living makes the immune system over-reactive to random allergens to the thought that chemicals in swimming pools are responsible. What these ideas have in common is the suggestion that some environmental change which accompanies economic development is the cause. A group of researchers led by Shadmehr Demehri of Washington University, in St Louis, believe these explanations are looking in the wrong place. Asthma is not, they think, caused directly by environmental factors. Rather, the link is indirect. The direct cause is a chemical distress signal produced in skin that is damaged by another hazard of modern life: eczema.

Eczema is also on the rise in the industrialised world, in the same sorts of countries where asthma is a problem. Unlike asthma it is not dangerous, so people rarely worry about it. Nevertheless, 17% of children in America have it, and similarly high figures are found in Australia, Britain and New Zealand. What is particularly intriguing is that many people with eczema go on to develop asthma (in America the figure is 70%). That compares with an asthma prevalence of 4-8% in the general population. As they describe in Public Library of Science Biology, Dr Demehri and his colleagues now believe they know what causes this link.

The culprit is thymic stromal lymphopoietin (TSLP), a signalling molecule secreted by damaged skin cells which elicits a strong immune response from the body to fight off invaders. Dr Demehri and his team hypothesised that eczema-induced TSLP enters the bloodstream and, when it arrives at the lungs, sensitises them so that they react to allergens that would not previously have bothered them. In other words, they become asthmatic.

They tested their hypothesis in a series of experiments on mice. First, using genetic engineering, they created mice prone to the kind of skin defects found in eczema. These mice were, as they hoped, susceptible to asthma. Then they used additional engineering to delete the gene for the receptor molecule which picks up TSLP in the lungs. These mice no longer developed asthma. Thirdly, they engineered mice to produce high levels of TSLP in their skin in the absence of other skin problems. These mice also developed asthma.

Taken together these experiments indicate—at least in mice—that skin damage creates susceptibility to asthma by releasing TSLP. If that proves true in people, too, it suggests several ways asthma might be prevented. One is to take eczema seriously, and treat it early. The usual treatment is to apply steroids to the damaged skin, but there is evidence that some parents reject this treatment for their children. If a link between eczema and asthma were properly established, that reluctance would probably diminish. In the longer term, it might be possible to devise drugs that inhibit the production of TSLP or interfere with TSLP-receptor molecules in the lungs. Better still, though, would be to work out what aspect of modern life causes eczema.

One possible culprit related both to cleanliness and bathing is the widespread use of detergents. By degreasing the skin, modern detergents might lead to infection and inflammation. At the moment, that idea is just speculation. But the question is an itch that certainly needs a scratch.

The information in the talk is very general, probably less than what is in the Wiki. But the information sinks in much better from a live presentation than reading dry text. Let alone that I probably won’t read the information on my own. Today I learned that mental problem is partly genetic and partly environmental. Mental problem can not be cured, it can only be controlled or maintained. The treatment always begins with the psychiatrist, get some pills to stabilize the problem, then consult with psychologist to work on mental therapy. The hardest part is to get the patient aware of the problem and willing to accept treatment. Many audiences asked questions relate to how to treatment the problem in the Q&A session. Too bad that I forgot to ask the speaker whether smoking will make schizophrenia worse.

In addition to the content of the talk, I have some inspiration about volunteer works. It is the first time I have first hand experience about grass root charity organization. Unlike the big volunteer program, like the Red Cross or charity run by churches, the CMWAC has a total different aura. It is more like a support group for Chinese families with mental problem. The founder and chair person also acted as the translator for the talk. Juxtaposing her side by side with the psychology professor, I can see two difference kind of volunteers. The professor is the technical expert and gives credibility to the talk. The chair person knows a lot about hands on knowledge and very enthusiastic in her volunteer work. It is not that one is better than another, but rather the kinds of two volunteers make a good complement to each other. It is like scientists and research assistants, engineers and technicians, doctor and nurses, it takes two to get the job done.

殺一警百是嗜血的中國人獨有的觀念﹐這有違西方公義原則中的公平慨念。根據公義原則﹐任何賞罰必需要有規則可尋。這個規則必需要事前公開﹐不能事後因應民情去追加。若果對賞罰規則作出改動﹐加重某些行為的刑罰﹐也只適用於改動後的犯錯﹐不能追逆至已經犯了的錯誤。最重要是對每一個人也相同處理﹐不能因為是第一宗案件便罰重些﹐又或者只高調針對某些犯事者﹐必需要給所有犯事的人相同懲罰。今次事件很不幸有病人失救﹐但是根據醫管局的內部指引規條﹐又可以用什麼條例去重罰高層呢﹖

嚴格來說高層並沒有見死不救﹐犯下見死不救大錯是那個不知變通的前線員工。誠如醫管局報告所言﹐高層犯的錯誤是處理緊急事件的表現及管理手法有問題。說白了便是他們久缺傳媒公關常識﹐堅稱醫院按指引辨事沒有錯誤﹐出事後胡亂說話才會引起公憤。其實高層當日只要把矛頭指向指引﹐承諾會檢討和改善指引彊化的問題﹐便可以避過這一場公關災難。把犯錯的責任全推在指引身上﹐把所有曾經參與指引的人拖下水﹐於是所有人也有份犯錯。不過人人犯錯等於沒有一個人犯錯﹐於是沒有一個人要負上責任﹐把問題歸咎制度是最好的辨法。改革指引的善後工作﹐其實與醫管局報告的要求差不多。倒不如一開始便自己提出來做了﹐不用現在給醫管局責罰才做。

其實群眾要求重罰﹐恐怕最後會弄巧反拙。若果動不動犯錯便要革職﹐醫院員工為求自保﹐只會少做少錯不做不錯﹐更加抱著指引當護身符。

I drove all the way to VGH to pick up my father-in-law without know he can’t be discharged today. It is a total waste of my time. Maybe the hospital should learn from the airport, setup a website for the family of patients to check discharge status. Like the arrival information in the airport, you can see whether the discharge is delayed or not. Then my friend, Chris, hear my idea and joke about this idea, maybe they should add the canceled status like a flight. If the patient is canceled, you don’t have to pick him up anymore, because he is already dead. Pat said it is cruel and suggested the cancel status change to the departure gate to Heaven.

I remember I had a friend in university with similar problem. Half of his face is much darker than the rest of his skin. When I know him, I am old enough not to make fun of his appearance. He is a nice guy and reasonably good in school and sports. Actually, after we get to know him, we quickly overlook the mark on the face, and treat him just like any other one of us. I think he even manage to get a girlfriend in school. Ok, he is a bit ugly, but so what? Guys should not worry too much about his appearance. For guys, it’s what underneath the face hide inside the skull counts. I am not too worry about my friend’s boy. Maybe he will have a few harsh years in kindergarten or elementary school. But once he survived that stage and develop a healthy personality, he will be on equal foot with another for the rest of his life. On the other hand, if a baby girl got this “Nevus of Ota” disease I can’t image how miserable her life will be.

Our family dog, Charlie, is 13 years old. Pat grew up with it since a little girl. Charlie is a very adorable golden retriever. Now, it is getting old and it can’t even get up on its own due hip problem. We have to help it getting up by giving it support on the stomach. Pat took it to visit a vet yesterday and did its annual lab test. The results come back today and reveal that it has cancer. We will see whether the insurance cover for the surgery fee. If not, we will just let it live its remaining days peaceful. It is simply cheaper to buy a new dog than fixing the old one. I guess 13 years of life is long enough for a dog. It does not do much everyday, spent most of time sleeping and gets up only for food and its daily walk. To Charlie, everyday is just the repeat of the previous day. Life of a dog seems so meaningless, all it does is eat, sleep, walk, pee and shit. The function of a pet is to give joy and pleasure to its owner. When owning a pet brings more trouble than pleasure, maybe it is time send it to SPCA to end its suffering.

There is a parsimonious manager in my company.  He is so cheap that when he book air ticket, he will take a transfer instead of direct flight to save $100 for the company.  I wonder when he travel to India, which Malaria vaccine did he get.  I bet he would take the cheap one over the expensive one.  If he suffer from the side effects, like nausea, vomiting, abdominal discomfort, diarrhea, headache, dizziness, insomnia, would he regret not spending the company’s money?