Patients with retinitis pigmentosa (RP) typically develop night blindness early in life due to loss of rod photoreceptors. The remaining cone photoreceptors are the mainstay of their vision; however, over years or decades, these cones slowly degenerate, leading to blindness. We created transgenic pigs that express a mutated rhodopsin gene (Pro347Leu). Like RP patients with the same mutation, these pigs have early and severe rod loss; initially their cones are relatively spared, but these surviving cones slowly degenerate. By age 20 months, there is only a single layer of morphologically abnormal cones and the cone electroretinogram is markedly reduced. Given the strong similarities in phenotype to that of RP patients, these transgenic pigs will provide a large animal model for study of the protracted phase of cone degeneration found in RP and for preclinical treatment trials.

We report on a 27-year-old male Caucasian with severe haemophilia A who presented with acute onset of neck pain with cervical nerve root irritation, due to a spinal epidural haematoma. His past medical history revealed carrying of a moderate weight as a possible traumatic mechanism. Under immediate factor VIII replacement therapy complete remission of the symptoms was achieved within several days. The diagnosis of spinal epidural haematoma and complete resorption was revealed by initial and follow-up magnetic resonance imaging studies of the cervical spine. Having reviewed the literature on spinal epidural haematoma, we present an overview of the treatment and outcome as regards haemophilia.

Yeast chromatin, isolated by a rapid procedure contains in addition to histones H2A, H2B, H3 and H4 a fifth major basic protein. This fifth polypeptide is not an intrinsic component of the nucleosome structure. It has properties of both histone and nonhistone proteins and might represent an early form of histone H1 and of high mobility group nonhistone proteins of higher eukaryotes. Electron microscopic visualization of isolated yeast nucleosomes substaniates further the similarity of the chromatin structudre of this unicellular eukaryote to that of higher eukaryotes.

We report the second confirmed case of the haemophilia B 'Brandenberg' phenotype. At the time of testing, patient HB530 was a 17-year-old post-puberty male with a persistent, clinically severe bleeding disorder and markedly reduced plasma procoagulant factor IX activity (< 1%). Sequencing studies revealed a G-->A transition at bp - 26 within the promoter region of the factor IX gene. This case report confirms the observation that not all patients with promoter mutations improve after puberty and supports the hypothesis that bp - 26 is a critical binding site within the factor IX gene promoter region for both constitutive as well as androgen-inducible transcription factors.

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