Wednesday, February 20, 2008

`glucose-monitoring watch



Cover Story
Sensors keep watch on Diabetes
Clever sensor design turned a 100-year-old medical observation into a new kind of glucose monitor

Joseph Ogando, Materials Editor -- Design News, June 4, 2001


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Redwood City, CA —If Dick Tracy had diabetes, he'd probably wear the GlucoWatch® Biographer, a new glucose monitor from Cygnus Corp. Rather than sitting on a table somewhere, this monitor straps to the patient's wrist and uses a patented electrochemical sensor to measure glucose levels through the skin. More than just a gizmo, the device could revolutionize the way diabetics manage their disease. "It's a godsend," says Dr. Steven Edelman, director of diabetes research at the University of California San Diego and founder of Taking Control of Your Diabetes, a patient-education organization.

Unlike home glucose monitors, which provide a snap shot of blood sugar levels only as often as patients choose to prick their fingers and draw blood for analysis, the GlucoWatch works both continuously and non-invasively. The device displays a new glucose reading every 20 minutes and sounds an alarm if blood sugar gets too high or low. It also stores up to 4,000 readings worth of historical information, revealing blood sugar fluctuations that intermittent monitoring could easily miss. "We've never been able to collect this kind of continuous trend information before," Edelman says. And for diabetics, reliable blood sugar information can matter almost as much as insulin itself. According to Edelman, a sketchy picture of overall blood sugar levels makes it difficult to control diabetes by maintaining blood sugar levels within a healthy range. Left uncontrolled, diabetes can bring on blindness, amputation, heart disease, or worse. "I've seen people die when they don't have a handle on their blood sugar," he says.

The GlucoWatch is a blood sugar monitor that patients wear.
Though it just won FDA approval at the end of March and only recently went on sale in the United Kingdom, the GlucoWatch actually got its start almost 100 years ago with the observation that an electric current can selectively transport chemicals through human skin. This transport phenomenon, called "iontophoresis," has historically been seen as a one-way street, a way to get chemicals into the body. Cygnus scientists and engineers took the opposite tack, creating a device that reverses iontophoresis to get the glucose out. "A lot of substances can be measured through reverse iontophoresis, but we felt there was a great unmet need for glucose monitoring," says Dr. Russell Potts, a biochemist and Cygnus' vice president of research.

With a boxy appearance best described as "early digital," the 2 × 1 × 0.5-inch GlucoWatch won't soon be mistaken for a Rolex—or even a Timex. But the underside of the watch houses an innovative biosensor that handles the important business of collecting glucose, breaking it down to produce an electrochemical signal, and measuring that signal before calculating a blood sugar reading. This disposable sensor, which snaps in place and lasts for 12 hours of continuous monitoring, handles these three tasks with two sets of screen-printed electrodes and enzyme-packed hydrogel collection discs.

Sugaring time. Each 20-minute analysis cycle starts as the sensor's silver-silverchloride iontophoresis electrode applies a 300-microamp current to the skin. For the next three minutes, positive and negative ions travel through the patient's skin to GlucoWatch's side-by-side collection discs, which serve as an anode and cathode during glucose extraction. This ion migration brings glucose along for the ride, depositing it at the cathode. "We ignore what happens at the anode," Potts notes.

Next, enzymes in a cathode disc chemically break down the glucose, producing a nanoamp-sized electrochemical signal that the device's platinum biosensing electrode measures over a seven-minute period. "This signal correlates extremely well to the glucose levels in the blood," Potts says. The GlucoWatch then applies proprietary algorithms to transform the raw signal—which the device integrates over the seven-minute sensing period—into a glucose measurement. For the next ten minutes of the cycle, the GlucoWatch repeats the same steps but with the sensor's polarity reversed. This way, the disc that acted as the anode in the first half of the cycle becomes the cathode in the second, in order to prevent the plating that would otherwise shorten sensor life.

The final glucose reading displayed by the GlucoWatch averages the two ten-minute cycles. Clinical studies conducted by Edelman show these readings to be about 15 to 20% accurate, inclusive of human calibration errors. "That's comparable with what most people get from home glucose monitors," he says.

In designing the biosensor, Cygnus engineers took pains to minimize complexity. One stroke of integration genius enabled them to reduce the number of electrodes that operate at any given point in the cycle from four down to three. They devised an iontophoresis electrode that does double duty as a counter electrode for the platinum "working" electrode as soon as the glucose extraction stops. A third reference electrode completes the three-electrode set. Each sensor has an identical pair of these electrode sets—one behind each hydrogel—in order to accommodate the polarity reversal.

Not so noisy. A lot of work, and several patents, went into maximizing the sensor's signal to noise ratio. Sensor efficiency counts for a lot because the GlucoWatch has to overcome the inefficiency of the glucose extraction through the skin. Potts notes that iontophoresis only summons up a tiny bit of glucose—about 1/10,000th the amount in a drop of blood. And that tiny sample produces a barely noticeable signal. "It's a formidable detection problem," he says, explaining that glucose breakdown produces a current of only a few hundred nanoamps. "At first we had a lot more noise than signal."

To come up with a sensor capable of working at nanoamp resolution, the company's engineers fought the noise with a patented electrode design that minimizes signal loss by distributing electrode surface area into discrete, electrically insulated pockets. Another efficiency boost for the sensor comes from physical "masks" that control how the glucose meets the sensor face. Located between the hydrogel discs and the electrodes, these barriers ensure that the glucose enters the biosensor normal to its face rather than radially. "The masks let the biosensor obtain accurate readings more quickly by reducing the distance glucose has to travel," Potts says.

The GlucoWatch's disposable sensor consists of ring-shaped electrode and hydrogel collection disc layers.
Other sources of noise turned up in the materials used to make the sensor, forcing Cygnus to wage a war on contamination. "We had found that some of the noise was chemical in nature," Potts says. Antioxidants and other additives used in early formulations of the hydrogel, for example, had their own electrochemical signatures, which skewed glucose readings. So did some of the solvents used in the screen-printing process for the electrodes. A big push toward purity in both materials sourcing and manufacturing steps dramatically reduced noise.

Ordinary innards. As for the GlucoWatch hardware, it consists almost entirely of common electrical components. "Our strategy was to miniaturize using off-the-shelf components," Potts says. Early on, the design team even considered and rejected optical methods for measuring glucose because it would have required more custom components than an electrochemical system. Yet rather than designing solely for miniaturization, the GlucoWatch engineers also had to balance size against affordability and ease-of-use.

In this case, smaller would not have been better because vision loss often accompanies uncontrolled diabetes. "We could have made the watch smaller, but too many diabetics would have trouble using it," Potts says. Cygnus engineers determined the right size of the buttons and screen by putting prototypes in front of focus groups.

The need to make the monitor and disposable sensor affordable further tempered any desire to create a svelte device. To keep costs low, the watch uses off-the shelf ASICs rather than a custom design that could deliver the same functionality in less real estate. And a standard AAA battery powers it even though more costly batteries would have taken up less space. "We wanted to use a battery that's both cheap and readily available," Potts says.

The GlucoWatch does have some ease-of-use limitations. The device needs a three-hour warm up period. It shouldn't be immersed. Too much sweat can change skin conductivity, triggering a temporary disruption of readings. And finally, the FDA approved the prescription-only GlucoWatch as an adjunct to home glucose monitoring systems, which must be used to provide an initial calibration reading.

But Edelman stresses that the GlucoWatch really represents the first, not the final, step in the evolution of continuous blood sugar monitoring. "Someday people will look back at this device and think of it as the Model T of glucose monitoring," says Edelman. "But for now, it's a Porsche."

Sunday, February 17, 2008

a good video about diabetic foot care

Authentic Aloo Matar

Authentic Aloo Matar


Submitted by ignayshus

Makes 4 servings


Found this at http://masalamagic.blogspot.com/ and enjoyed it thoroughly.

Ingredients
4 Potatoes - Peeled and Washed
1 cup Green Peas (Fresh or Frozen is good)
2 tsp Red Chili Powder
1/2 tsp Turmeric Powder
1 tsp Coriander Powder
1 tsp Cumin Seeds
2 tbsp Clarified Butter
1 Salt to taste
Directions
  1. Peel, Wash and Chop the Potatoes into cubes.

  2. Recipe calls for a pressure cooker, but I just cooked the potatoes in a pyrex bowl covered with syran wrap in the microwave.

  3. Heat the clarified butter, then add the cumin seeds and the green peas.

  4. Add all the dry powders, mix well and saute for about a minute.

  5. Add the chopped potato cubes and salt, mix well.

  6. Close with the lid and cook the mixture on medium until heated thoroughly.

  7. Garnish with chopped Cilantro and serve hot.

Categories

Side Dish, Indian

Nutrition Facts
Serving Size 258.6g

Amount Per Serving
Calories
236
Calories from Fat
58
% Daily Value*
Total Fat
6.4g
10%
Saturated Fat
3.7g
19%
Cholesterol
15mg
5%
Sodium
68mg
3%
Total Carbohydrates
39.8g
13%
Dietary Fiber
7.5g
30%
Sugars
4.6g
Protein
5.8g

Vitamin A 17% Vitamin C 96%
Calcium 4% Iron 12%
* Based on a 2000 calorie diet

Nutritional details are an estimate and should only be used as a guide for approximation.
Legend



Calorie Breakdown (?)
Nutrition Breakdown
Daily Values (?)
Daily Values

Nutritional Analysis

Nutrition Grade
96% confidence
A-
Good points
  • Low in cholesterol
  • Low in sodium
  • High in dietary fiber
  • High in potassium
  • High in vitamin B6
  • Very high in vitamin C
  • Saturday, April 22, 2006

    File written by Adobe Photoshop 5.0

    Click the picture to see annotations
    File written by Adobe Photoshop 5.0 shan dancing drummer
    File written by Adobe Photoshop 5.0
    What is image annotation?

    an interesting shan dance from ?burma

    Friday, September 30, 2005

    Natural killer cells_islet cell transplants

    there are 2 big problems in islet cell transplants for curing (see the word CURE)diabetes .
    1) lack of sufficent donor islet cells .
    2)destruction of transplanted cells.
    may be we are finding ways and means of combating the second problem

    It is a proud moment for us to see an Indian (NAGENDRA SINGE) working with the japanese in USA

    The natural killer T-cell ligand -galactosylceramideprevents autoimmune diabetes in non-obese diabetic mice
    SEOKMANN HONG1, MICHAEL T. WILSON1, ISAO SERIZAWA2, LAN WU3, NAGENDRA SINGH1,
    OLGA V. NAIDENKO4, TORU MIURA2, TOMOKU HABA2, DAVID C. SCHERER1, JIE WEI1,
    MITCHELL KRONENBERG4, YASUHIKO KOEZUKA2 & LUC VAN KAER1
    1Howard Hughes Medical Institute, Department of Microbiology and Immunology,
    Vanderbilt University School of Medicine, Nashville, Tennessee, USA
    2Pharmaceutical Research Laboratory, Kirin Brewery Co, Ltd., Gunma, Japan
    3Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
    4La Jolla Institute for Allergy and Immunology, San Diego, California, USA
    S.H., M.T.W. and I.S. contributed equally to this study.
    Correspondence should be addressed to L.V.K.; e-mail: vankael@ctrvax.vanderbilt.edu

    base on this .
    the same chemical is found to help protect transplanted islet cells .
    Discovery Could Boost Type 1 Diabetes Care
    Researchers spot key player in success of transplanted insulin-producing cells
    TUESDAY, Sept. 27 (HealthDay News) -- The survival of transplanted insulin-producing cells is improved when activation of "natural killer T" immune cells is blocked, Japanese researchers report.
    They believe the finding could help boost the effectiveness of islet cell transplants for the treatment of insulin-dependent type 1 diabetes. This form of the disease (affecting about 5 percent of diabetics) is caused by the destruction of insulin-producing cells in the pancreas by the body's own immune T-cells.
    Transplantation of these "islet cells" requires patientto continue lifelong immunosuppression therapy.Even with immunosuppression treatment, up to half the transplanted islet cells are quickly destroyed by the patient's own T-cells, however.
    In their research with mice, the Japanese team showed that natural killer T (NTK) cells instigate this rapid destruction of transplanted islet cells. When the NKT cells become activated -- most likely in response to the stress of the transplant procedure -- they produce an inflammatory molecule called interferon (IFN)-gamma.
    It's this molecule that helps activate immune T-cells to destroy islet cells, the researchers report in the Oct. 3 issue of the Journal of Experimental Medicine.
    Transplanted islet cells survived in mice that lacked NKT cells or were unable to produce IFN-gamma, the researchers found. They also found that multiple doses of the drug alpha-galactosylceramide caused NKT cells to produce less IFN-gamma. Decreased production of IFN-gamma greatly improved the survival of transplanted islet cells, the study found.
    According to the Japanese team, multiple doses of the drug -- currently in human clinical trials -- may help prevent the early loss of transplanted islet cells in humans.


    In an extension of the same anology
    this same chemical may prove to be useful in preventing rejection of other transplanted organs .

    getting serious about telugu Diabetes educational site

    Ihave been collecting content for the last 1 year to stsart this web site but hasnt had enough spare time to up load articles

    it will be set up at daibetiisu.com
    unless we educate evry one about theses diseases and how to take care of them properly we are going to see a major portion of GDP of India being wasted on treating complications and in wasted man hours .