Sea urchin ovoperoxidase: oocyte-specific member of a heme-dependent peroxidase superfamily that functions in the block to polyspermy.

Ovoperoxidase is one of several oocyte-specific proteins that are stored within sea urchin cortical granules, released during the cortical reaction, and incorporated into the newly formed fertilization envelope. Ovoperoxidase plays a particularly important role in this process, crosslinking the envelope into a hardened matrix that is insensitive to biochemical and mechanical challenges and thus providing a permanent block to polyspermy. Here we present the primary structures of two ovoperoxidases as predicted from cDNAs cloned from the sea urchins Strongylocentrotus purpuratus (AF035380) and Lytechinus variegatus (AF035381). We also present a proposed scheme for the post-translational processing of ovoperoxidase based upon comparisons between the cDNA and protein structures and taking into account previously published reports. The sea urchin ovoperoxidase sequences conform to a profile shared by members of a heme-dependent animal peroxidase family, including the mammalian myelo-, lacto-, eosinophil, and thyroid peroxidases. Using in situ RNA hybridizations, we showed that the mRNA of S. purpuratus ovoperoxidase (4 kb) is present exclusively in oocytes, and is turned over rapidly following germinal vesicle breakdown. Taking into account our immunoblot and N-terminal sequencing data along with reports from similar peroxidases, we propose that ovoperoxidases are synthesized in a pre-pro form and proteolytically processed to result in the 70 and 50 kDa forms that are found in the fertilization envelope. The sequence and structural data presented here will facilitate our continuing studies of the biogenesis of cortical granules and the fertilization envelope. Additionally, since ovoperoxidase activities have been reported in a wide range of animals, these cDNAs will be useful in uncovering similar peroxidases used in the fertilization reactions of other metazoan eggs.

School-based health centers and school nurses: cementing the collaboration.

As school health personnel respond to the changing needs of children, new models are being developed and traditional models are being reexamined. The role of the school nurse is expanding at the same time as school-based health centers are increasing in number. Partnerships between school-based health centers and school nurses are critical for the success of school-based health centers, and partnerships will enhance and expand roles for school nurses. This paper clarifies the role of each in three areas: collaboration, communication, and cooperation. In addition, obstacles to partnerships are examined. The goal of this collaboration is a shared vision for the continuum of school health services in which school nurse and school health center serve integral roles. Elements for successful collaboration between nurse and health center are reviewed, including clarifying roles, shared leadership and program ownership, cooperative training and continuing education, negotiating conflict, and most importantly, maintaining mutual support and respect.

A diversity of enzymes involved in the regulation of reversible tyrosine phosphorylation in sea urchin eggs and embryos.

Reversible tyrosine phosphorylation is involved in the fertilization reaction and early embryogenesis of the sea urchin (Foltz and Shilling, 1993; Ramachandran et al., 1993). To determine the enzymes present that may be involved in this regulation, we used a PCR screen to identify sequences that encode protein tyrosine kinases (PTK) and protein tyrosine phosphatases (PTP). We identified five PTKs and eight PTPs using cDNA libraries from two sea urchin species at two different stages of development, and the similarities to known PTK and PTP amino acid sequences ranged from 70 to 95%. The cognate proteins represented both "receptor"-class and cytoplasmic enzymes. Using RNAse protection assays we found that the respective mRNAs showed many accumulation profiles that we have grouped into three basic patterns: (1) mRNA levels that do not vary by more than two to three times throughout development; (2) mRNA levels highest in eggs or ovaries; and (3) mRNA levels highest in gastrula or pluteus stages. mRNAs specific to adult somatic cells of the ovary were not found, nor were mRNAs that accumulated selectively at the blastula stage. The results show that a diversity of enzymes involved in the regulation of reversible tyrosine phosphorylation is present in eggs and embryos of the sea urchin and that the differential accumulation in development of each mRNA suggests specific functional responsibilities by members of these enzyme families.

[Psoriatic osteopathy--results of histomorphometric studies]. / Die psoriatische Osteopathie--Ergebnisse histomorphometrischer Untersuchungen.

In 23 patients with psoriatic arthritis and 9 patients with psoriasis without joint involvement, we took bone biopsies from the iliac crest. Histomorphometrical investigations showed that the volume density of the bone was not decreased in either group of patients, but we found a high rate of turnover remodelling. An elevated rate of bone turnover is regarded as the characteristic principle of "psoriatic osteopathy", which--more exactly--should be called "latent osteopathy". Deficiency of vitamin D is discussed as a possible etiological factor.

[Psoriatic osteopathy]. / Untersuchungen zur psoriatischen Osteopathie.

In order to make evident an up to now only postulated generalized osteopathy in psoriatics in 24 patients with psoriasis and 24 patients with psoriatic arthritis the serum-calcium levels, the alkaline phosphatase in the serum and the excretion of hydroxyprolin in the urine were determined. Moreover, the bone bioptates of 25 patients with psoriatic arthritis and 10 patients with psoriasis were histologically examined and morphometrically measured, respectively. The examinations give evidence for the presence of a generalized "latent" osteopathy in the sense of an increased bone turnover rate without loss of bone volume (high turnover remodeling) in patients with psoriatic arthritis as well as in those with psoriasis without arthritis. As a common pathogenetically significant factor for dermatosis and osteopathy a latent vitamin D deficiency and a D-hormone resistance is discussed.

[Vitamin A status of patients with chronic renal failure in relation to renal osteodystrophy]. / Untersuchungen über den Vitamin-A-Status von Patienten mit chronischer Niereninsuffizienz in Beziehung zur renalen Osteodystrophie.

In patients with chronic renal insufficiency and dialysis patients as well as in normal persons determinations of vitamin A in the serum and in the bone were performed and related to the parameters of the bone metabolism and to the histomorphometric investigation of the bone. The vitamin A serum levels were significantly increased in the two groups of patients, however, did not show any differences between the patients with an osteoidosis or the combination of osteoidosis and fibroosteoclasia. There were no correlations to calcium, phosphorus, PTH and to the alkaline phosphatase as well as to the individual histomorphometric data. The vitamin A content of the bone was low and did not show any differences to the normal persons. On the other hand, there were significant relations between the parathormone and the parameters of the regeneration and the absorption of the bones. An additional influence of vitamin A on the bone disturbance, eventually by the activation of the osteoclasts cannot be excluded.

[Nature and significance of osteopenia]. / Wesen und Bedeutung der Osteopenie.

New realisations on the regulation of bone and calcium metabolism by hormones and vitamins, modern methods of the radiologic and morphologico-morphometric diagnostics considerably increased our knowledge about the deminerlising diseases of the skeletal system. The possibilities for diagnostics and therapy resulting from this are restricted in practice by a non-adequate nomenclature. The introduction of the disease group notion "osteopenia" for all demineralising processes and its definition as well as the representation of the differential diagnostics of osteolamacia, fibrosteoclasia and syndrome of osteoporosis as clinical main representatives of osteopenia shall help to prevent diagnostic and therapeutic errors.