Corneal endothelium damage with intraocular lenses: contact adhesion between surgical materials and tissue.

Intraocular lenses destroy corneal endothelial cells by contact adhesion between the acrylic lens and endothelial surfaces during cataract surgery. Glass and rubber surgical glove surfaces produce similar cell damage. This phenomenon may be important in many surgical procedures and appears to be preventable if a hydrophilic polymer interface is interposed between contacting tissue and the surfaces of materials used.

Peritoneal adhesions: prevention with the use of hydrophilic polymer coatings.

Postoperative adhesions, especially peritoneal adhesions, pose an increasingly serious surgical problem. Modern surgical studies have generally attempted to deal with the problem after extensive surgical tissue damage has already occurred. This report focuses on our preliminary findings from exploratory laparotomies with canine and rat animal models, which suggest (1) that inadvertent and generally unappreciated serosal trauma may occur by contact adhesion as well as abrasion and drying mechanisms and (2) that hydrophilic polymer coatings, such as providone (polyvinylpyrrolidone), may be effective in protecting the peritoneal surface from damage. This opens up an important new approach to dealing with the problem: application of adhesive and lubricating tissue and surgical material coatings prior to surgical manipulations to limit tissue damage and thereby minimize postoperative complications. The implications of this study to many other surgical procedures may also be of considerable consequence.

Polycarbonate intraocular lenses.

Bisphenol-A polycarbonate has been investigated as an improved polymer for ocular implants, especially for intraocular lenses (IOLs). Polycarbonate properties afford special opportunities for development of tougher, stronger, one-piece IOLs. Autoclave or gamma sterilizability and a higher refractive index may provide additional IOL advantages over polymethylmethacrylate. Implant studies in rabbits have shown polycarbonate IOLs to be well tolerated in the anterior chamber for 2.5 years. Polycarbonate appears promising for new IOLs and other ocular implant applications.

Dr Roger McNeill and public health in the Highlands and islands of Scotland.

Roger McNeill was born in 1853 on Colonsay in the Inner Hebrides, the son of a cattle herder. He graduated with a degree in medicine from Edinburgh University, where he studied with Joseph Lister, among others. After working in London during a smallpox epidemic, he received a gold medal and honours for his M.D. thesis in 1881. McNeill returned to Scotland as the Resident Medical Officer at Gesto Hospital on the Isle of Skye. From there, he launched and published the first statistical research about the health of Highland crofters. His was an illustrious yet understated career in public health: he was the first president of the Caledonian Medical Society (1881-82), he earned a Diploma in Public Health from Cambridge University (1889), he was the first Medical Officer of Health for Argyll (1890-1924), wrote The Prevention of Epidemics and the Construction and Management of Isolation Hospitals (1894), and was the first witness before Parliament's Dewar Committee in Oban in 1912. McNeill and other members of the Caledonian Medical Society testified about medical services in remote Scotland, encouraging a revolution in healthcare throughout the Highlands and Islands. The committee's report led to the foundation of the Highlands and Islands Medical Service, a forerunner of the National Health Service established in 1948.

Excessive twinning in a rural American genealogy: the demographic pedigree.

Excessive twinning in an extended family of rural Missouri concentrates in the isolated generations of 1874-1930s. Moderate inbreeding, larger sibships to older mothers, and access to local doctors may have combined to enhance this familial twinning. These biosocial factors are similar to an isolated case of excessive twinning in Scotland.

Excessive twinning in a rural American genealogy.

A family record of 1693 descendants in rural Missouri exhibits a twinning rate of 2 X 2%. Weinberg's Differential Rule estimates the level of monozygosity in this twin sample at 61-83%, unlike previous results dominated by dizygosity . These historical data cannot directly support a genetic basis for monozygosity though. Clinical studies seem the best solution to the genetics of twinning.

A triplet maternity in a reduced population with excessive twinning.

In 1991 a triplet maternity of same-sex (FFF) occurred in a depopulated community of Argyll, Scotland, with a history of excessive, same-sex twinning. Due to a stillbirth and its confidentiality, the maternity was recorded as a twin birth. Using public registers may result in underestimation of rates for higher multiple conceptions and births in local districts.

Prevention of endothelial damage from intraocular lens insertion.

Previous studies have indicated that approximately half the corneal endothelial cells can be lost at the time of IOL insertion. Momentary contact between the methacrylate surface and the endothelial cell appears to cause an adhesion between these surfaces which damages the cells even without prolonged contact. Although other factors may also damage the endothelium, this endothelial damage which seems clinically important can be prevented by simply dipping IOL in simple solutions of PVP.

Intraocular-lens-endothelial interface: adhesive force measurements.

An instrument for measuring the force of adhesion between intraocular lens materials and the endothelium of excised rabbit corneas was constructed. The adhesion force was measured for polymethylmethacrylate (PMMA), polyhydroxyethylmethacrylate (PHEMA), Duragel (amino-polyamide hydrogel), PMMA surface grafted with polyvinylpyrrolidone, and PMMA surface treated with sodium hyaluronate (Healon). The force of adhesion was reduced considerably when the PMMA surface was modified with a hydrophilic polymer coating. This is consistent with previous studies showing reduced endothelium cell damage for hydrophilic polymer coated intraocular lenses. Adhesive forces were also decreased by addition of polyvinyl alcohol or gelatin to the saline solution in which the corneas were immersed. Extension of this type of measurement to pericardium, vascular endothelium, and peritoneum surfaces may also be important to understand tissue damage problems in general surgery.