Haplotype-based analysis resolves missing heritability in oculocutaneous albinism type 1B

Oculocutaneous albinism (OCA) is a rare disorder of pigment production. Affected individuals have variably decreased global pigmentation and visual-developmental changes that lead to low vision. OCA is notable for significant missing heritability, particularly among individuals with residual pigmentation. Tyrosinase (TYR) is the rate-limiting enzyme in melanin pigment biosynthesis and mutations that decrease enzyme function are one of the most common causes of OCA. We present the analysis of high-depth short-read TYR sequencing data for a cohort of 352 OCA probands, ∼50% of whom were previously sequenced without yielding a definitive diagnostic result. Our analysis identified 66 TYR single-nucleotide variants (SNVs) and small insertion/deletions (indels), 3 structural variants, and a rare haplotype comprised of two common frequency variants (p.Ser192Tyr and p.Arg402Gln) in cis-orientation, present in 149/352 OCA probands. We further describe a detailed analysis of the disease-causing haplotype, p.[Ser192Tyr; Arg402Gln] ("cis-YQ"). Haplotype analysis suggests that the cis-YQ allele arose by recombination and that multiple cis-YQ haplotypes are segregating in OCA-affected individuals and control populations. The cis-YQ allele is the most common disease-causing allele in our cohort, representing 19.1% (57/298) of TYR pathogenic alleles in individuals with type 1 (TYR-associated) OCA. Finally, among the 66 TYR variants, we found several additional alleles defined by a cis-oriented combination of minor, potentially hypomorph-producing alleles at common variant sites plus a second, rare pathogenic variant. Together, these results suggest that identification of phased variants for the full TYR locus are required for an exhaustive assessment for potentially disease-causing alleles.

General properties of the interaction between animals and ELF electric fields

An analysis is given of the interaction between extremely low-frequency (ELF) electric fields and animals of arbitrary body shape. This analysis is based on three approximations which are valid in the ELF range: In living tissues, capacitive (displacement) currents are negligible compared to conduction currents; effects resulting from the finite velocity of propagation of electromagnetic fields are negligible; skin effect in living tissues is negligible. Major conclusions of the analysis are: (a) The electric field outside the body, the induced charge on the surface of the body, and the total current crossing any section through the body (eg, through the neck or limbs) are completely determined by the characteristics of the applied ELF electric field, the shape of the body, its location relative to ground and other conductors, and any conduction currents from the body to ground or other conductors. (b) All of the quantities in (a) can be measured using conducting animal models. (c) The magnitudes of the electric field outside the body and the induced charge density on the surface of the body are independent of frequency, in the ELF range, when the body is either insulated from or shorted to ground (and any other conductors in the system). (d) The only quantities affected by the electrical properties of the tissues comprising the body are the current density and electric field inside the body. (e) The electric field outside and inside a body will be unchanged by a scaled change in its size.

The use of 22Na as a tracer for long-term bone mineral turnover studies

Sodium-22 has been studied as a tracer for bone mineral metabolism in rats and dogs. When incorporated into bone during growth from birth to adulthood, the bone becomes uniformly tagged with 22Na, which is released through the metabolic turnover of the bone. The 22Na not incorporated in the bone matrix is rapidly excreted within a few days when animals are fed high, but nontoxic levels of NaCl. The 22Na tracer can be used to measure bone mineral loss in animals during space flight and in research on bone disease.

Restraint, venipuncture, endotracheal intubation, and anesthesia of miniature swine

Miniature swine are useful as experimental animals for investigations involving major surgical procedures, provided that proper restraint and anesthetic methods are employed. The methods and drugs described herein are not intended to be all-inclusive but rather those found most applicable to a wide variety of studies with miniature swine at this laboratory. This report is intended primarily to guide those unfamiliar in handling miniature swine during initiation of studies with that species. For chemical restraint during minor procedures, diazepam, at a dose of 5.5-8.5 mg/kg im, has become the drug of choice. For surgical anesthesia, optimal results have been obtained using thiamylal sodium iv for induction of anesthesia and maintained by 0.5-1.5% halothane administered via an endotracheal cannula. Pentobarbital sodium may be used to produce surgical anesthesia but is generally unsatisfactory except for terminal procedures. Electroanesthesia, even with concomitant use of tranquilizing drugs, is difficult to control and results in very poor muscle relaxation.

Bends: detection of circulating gas emboli with external sensor

Circulating gas emboli associated with rapid decompression are detectable in superficial vessels of animals by the use of an ultrasonic Doppler flowmeter transducer which is applied externally.