Tyrosine 3-hydroxylase (TH, EC 1.14.16.2) catalyzes the first and rate-limiting step of the catecholamine biosynthetic pathway in the nervous and endocrine systems. The TH locus was disrupted in mouse embryonic stem cells by homologous recombination. Mice heterozygous for the TH mutation were apparently normal. In these mice, TH activity in the embryos and adult tissues was less than 50% of the wild-type values, but the catecholamine level was decreased only moderately in the developing animals and was maintained normally at adulthood, suggesting the presence of a regulatory mechanism for ensuring the proper catecholamine level during animal development. In contrast, the homozygous mutant mice died at a late stage of embryonic development or shortly after birth. Both TH mRNA and enzyme activity were lacking in the homozygous mutants, which thus explained the severe depletion of catecholamines. These changes, however, did not affect gross morphological development of the cells that normally express high catecholamine levels. Analysis of electrocardiograms of surviving newborn mutants showed bradycardia, suggesting an alteration of cardiac functions in the homozygous mice that may lead to the lethality of this mutation. In addition, transfer of a human TH transgene into the homozygous mice corrected the mutant phenotype, showing recovery of TH activity by expression of the human enzyme. These results indicate that TH is essential for survival of the animals during the late gestational development and after birth.Catecholaminergic neurons, which include dopaminergic, noradrenergic, and adrenergic neurons, are located in discrete regions in the central nervous system and have an important role in a wide range of brain functions, such as locomotion, behavior, sleep, memory, and learning. In the peripheral tissues, sympathetic neurons are noradrenergic, and adrenomedullary chromaffin cells produce noradrenaline and adrenaline as hormones. During vertebrate development, catecholaminergic phenotypes are generated from a given neuronal lineage. The primordial catecholaminergic neurons appear in the intermediate zone of the neural tube at the early embryonic stage (reviewed in Ref.

We have developed a transgenic approach, termed immunotoxin-mediated cell targeting (IMCT), to ablate conditionally selective neurons in the brain with the cytotoxic activity of immunotoxins. Transgenic mice were created that express the human interleukin 2 receptor ca subunit (IL-2Ra) under the control of the dopamine j3-hydroxylase (DBH) gene promoter. The animals were treated intracerebroventricularly with a recombinant immunotoxin, anti-Tac(Fv)-PE40, which selectively kills animal cells bearing human IL-2Ra. The immunotoxin caused a characteristic behavioral abnormality only in the transgenic mice. This was accompanied by a dramatic loss of DBH-containing neurons and a significant decrease in DBH activity and norepinephrine levels in various regions of the brain. IMCT should provide a general technique to create animal models of human neurodegenerative disorders by targeting neurons or other cell types.

Venipuncture is a routine procedure performed at medical institutions for blood collection and blood donation, as well as for health screening and testing. Venipuncture is invasive and usually mildly painful, but it occasionally causes internal bleeding and chronic persistent pain, which is referred to as complex regional pain syndrome. The most common site of venipuncture is the upper arm. The present study macroscopically and anatomically ascertained positional relationships between cutaneous nerves and veins in the cubital (aka antecubital) fossa in many cadaveric dissections to determine the risk of peripheral nerve injury during venipuncture. We identified the most suitable venipuncture site in the upper arm. The medial cutaneous nerve of the forearm (MCNF) passed above the median cubital vein (MCBV) in 27 of 128 cases (21.1%), and was located inferior to the MCBV in 37 of 128 cases (28.9%). The MCBV also passed above the lateral cutaneous nerve forearm (LCNF) in 8 of 128 cases (6.2%). The LCNF was located deeper than the MCBV in 56 of 128 cases (43.8%). The distribution of cutaneous veins and nerves widely varies, and while no single area suitable for all individuals was identified, puncture of the MCBV near the cephalic vein is the least likely to cause nerve damage.

Adriamycin (ADR) is effective against a wide range of human neoplasms. However, its clinical use is compromised by serious cardiac toxicity, possibly through induction of peroxidation in cardiac lipids. Ascorbic acid, a potent antioxidant, was examined for effect in reducing ADR toxicity in mice and guinea pigs. Ascorbic acid had no effect on the antitumor activity of ADR in mice inoculated with leukemia L1210 or Ehrlich ascites carcinoma, but it significantly prolonged the life of animals treated with ADR. ADR elevated lipid peroxide levels in mouse heart, and ascorbic acid prevented the elevation. The significant prevention of ADR-induced cardiomyopathy in guinea pigs by ascorbic acid was proved by electron microscopy. Ascorbic acid and the derivatives may delay general toxicity of ADR and also prevent the cardiac toxicity. The results also suggest the clinical efficacy of the combined treatment of ADR and ascorbic acid or the derivatives.

No abstract