Preclinical Development of the Islet Sheet
Bibliographic record
Abstract
The Islet Sheet is a thin planar bioartificial endocrine pancreas fabricated by gelling highly purified alginate and islets of Langerhans. Acellular alginate layers form a uniform immunoprotective barrier to host rejection of the encapsulated cells, with the tissue nourished by passive diffusion from adjacent host tissue. The overall thickness of the Islet Sheet, 250 microm, is chosen to maximize nutrient diffusion. In this paper we describe the early development of the Islet Sheet, including purification and fractionation of the alginates used, difficulties in maintaining sheet planarity, and preliminary metabolic studies in pancreatectomized dogs. In a key experiment, approximately 75,000 allogeneic islet equivalents in six Islet Sheets were sutured to the omentum of a 7-kg female beagle dog at the time of pancreatectomy. Fasting euglycemia was maintained for 84 days. Fed blood sugars were usually below 150 mg/dL. A single injection of 2 U insulin was administered on day 9, and antibiotics were administered for two weeks. No other drugs were used. IVGTT post implant was not normal, but seemed to improve between 30 and 60 days. Upon omentectomy and sheet removal the metabolic parameters deteriorated to a frankly diabetic state within seven days. The sheets did not remain flat, but fragments were recovered within hard, mostly acellular capsules. Dithizone staining showed islets within alginate sheets recovered from the interior of these capsules, suggesting that allogeneic islet tissue survived 84 days and was responsible for maintaining fasting euglycemia.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".