Freqently Asked Questions

Package Sizes

Q: How many implants are there in each package?

Different packages contain different numbers of implants. Please see Pricing Information for details.
For example, a Linplant Research Pack contains 40 implants.

Sales Agents

Q: Do you have a sales agent in foreign countries?

We ship directly to clients without sales agents.

Analysis

Q: Why can't the serum insulin level be assayed by solid-phase RIA or the like?

The implants contain bovine, porcine, or rDNA human insulin which produces anti-insulin antibodies in the rodent. The solid-phase RIA or the like is a replacement assay, i.e., radio-active iodine labeled insulin is first bound to the anti-insulin antibodies coated on a solid surface. When the bound iodine-labeled insulin is displaced by serum insulin, the difference in the cpm gives the serum insulin level. If there are anti-insulin antibodies in the serum sample, it will also bind the bound iodine-labeled insulin. Therefore, there are 2 processes of removing the bound iodine-labeled insulin from the solid surface giving results up to 60× higher than expected.

Q: Can we use HPLC to assay serum insulin?

The ~7% albumin will clog up the HPLC column. Heat coagulation of albumin will remove the insulin with it.

Q: How can we get the serum insulin level then?

Use pig insulin on diabetic pigs, bovine insulin on cows, or athymic rodents.

Q: We cannot get urine samples from mice to test for glucose or ketone!

Take a small plastic container or 250-mL glass beaker. Lift the mouse by the tail and yo-yo to let its front paws touch the bottom. It will urinate.

Q: How can we obtain reproducible blood sugar readings?

We recommend using STZ-induced mice to obtain more predictable blood sugar readings. The use of naturally-diabetic mice is not recommended.

Dose

Q: We use sub-optimal dose as recommended to treat our mildly-diabetic rats and want to keep them mildly hyperglycemic. But, they become normoglycemic?

Mildly hyperglycemic rats on implant have a high incidence of reversion.

Q: We use recommended dose to treat our STZ-induced hyperglycemic rodents, but most have gone hypoglycemic and some die?

Unlike natural diabetes, STZ induction gives varying severity in hyperglycemia. The recommended dose is for severly diabetic (defined as off the meter scale, >400 mg/dL or > 20 mmol/L) animals.
Hyperglycemia less than as just defined, requires less than the recommended doses. To get reproducibly severe diabetes in mouse, the STZ must be prepared just before injection at pH 4 (up to 4 injections at 65 mg/kg may be required).
For rats, practise tail vein sampling of 0.2 mL of blood using a 30G needle with success rate of 7 out of 10 trials. Then use 50 mg/kg freshly prepared STZ at pH 4 (not 65 mg) IV into the tail vein.
All rats will become severly diabetic in 3 days. Implant after 7 days.

Potency

Q: We have been using your implants for many years, but we received a recent package containing implants that are inactive even above the recommended dosage?

The package must have been X-rayed during shipping. Contact us for replacement.

Q: We have some implants left beyond the expiration date. Are they still good?

Of course. We have some implants that have been left on the shelf at room temperature for many years, and they still retain the same potency.

Insertion

Q: What is Betadine, and where can we get it?

Betadine is a tradename of Purdue Federick Company in North America. It is a 10% aqueous solution of polyvinylpyrrolidone complexed with iodine, and is universally used in the surgical operating room for disinfecting the skin surface. Sigma chemicals in St. Louis, MO, sells the dry powder form or ask your local pharmacy who may stock the 10% solution. Otherwise, ask your University/Institute veterinarian, who may provide you with a small amount with charge.

Q: We tried to insert the implants through a small skin incision which was sutured for closure. All the sites were soon infected. Why?

If you prefer incision, then strictly observe the aseptic practice. Close the wound with metal clips (not sutures). We highly recommend the use of the 12G trocar/stylet for implantation.

NOTE: For any further technical questions, please contact us by email at linshincanada@hotmail.com.