First clinical experiences with the new intracardial electrode "Helifix"

A new pervenous non-traumatic screw-in electrode has been developed and tested in 61 patients. Dislocation of this electrode occurred in 2 instances (3.3%) and an increase in threshold (exit-block) in 3 cases (5%) necessitated repositioning of the electrode.     

Measuring first ray mobility with a new device

First ray hypermobility has been linked to many abnormal conditions in the foot. First metatarsal vertical displacement is proportional to the measurement of first ray dorsiflexion. A new device that measures first ray mobility has been built and tested. The device applies a dorsiflexing force to the head of the first metatarsal and measures the amount of vertical displacement that results. The design and instrumentation of the device is described. A safe and reliable testing procedure for measuring maximal first ray displacement is discussed. Clinicians could use this measure when selecting treatment options for patients who suffer foot pathologies resulting from faulty mechanics of the first ray.     

Identification of lactoferrin complexes in bovine mammary secretions during mammary gland involution

Part of the antimicrobial activity of lactoferrin resides in its ability to bind to bacteria. The complexing of lactoferrin with other proteins could alter its activity. This study identified the presence of lactoferrin complexes in mammary secretions during mammary gland involution and determined the proportion of free and complexed lactoferrin in mammary secretions. Mammary secretions were collected from Holstein cows on d 7, 14, and 21 of involution. Proteins were fractionated from defatted, filtered mammary secretions by sucrose density gradient ultracentrifugation and by gel filtration chromatography. Proteins contained in separated fractions were identified by SDS-PAGE. The presence of lactoferrin was confirmed by immunoblot analysis. Lactoferrin was present as complexed forms of high molecular mass in mammary secretions at each day of involution. The majority of lactoferrin was present in complexes of higher molecular mass rather than as monomers. A majority of lactoferrin existed in fractions of approximately 250 kDa, although peaks of lactoferrin at 150, 300, and 800 kDa were also found. The presence of lactoferrin complexes may result from interactions with casein or immunoglobulins or from the formation of lactoferrin multimers in the secretions. The interaction of lactoferrin with other proteins in mammary secretions during involution may affect the antimicrobial properties of lactoferrin.     

Osteopontin expression in mammary gland development and tumorigenesis

Osteopontin (OPN) is a secreted phosphoprotein that binds to cells via an Arg-Gly-Asp sequence and to mineralized surfaces. The protein can mediate cell adhesion and is strongly implicated in transformation and tumorigenesis. We have examined the expression pattern of OPN in mouse mammary glands at different stages of postnatal development. Whereas OPN is expressed at low-to-moderate levels in mammary glands from virgin and pregnant mice, the levels of OPN mRNA are extremely high in the lactating gland, consistent with the presence of the protein in milk. Expression is highest at 2 days of lactation and declines thereafter, but it remains high through involution. OPN expression is restricted to small nests or groups of cells at 9 days of involution. These results suggest that OPN may play a specific role in the process of involution that may be distinct from its role during lactation. In mammary tumors arising spontaneously in transgenic mice expressing the oncogenes c-myc and/or v-Ha-ras under the control of the mouse mammary tumor virus promoter, the level of OPN expression is increased dramatically over that in the normal gland in these same animals. Numerous cells expressing OPN mRNA are widespread throughout the tumors. OPN protein is detectable by Western blotting in extracts from the mammary gland at 2 days of lactation and from the tumors, but not in mammary glands at other stages of development. We hypothesize that OPN is exported from most tissues and that the protein is only detectable in tissues elaborating fluids, such as the lactating mammary gland, or in pathological situations when expression of OPN is abnormally high, such as in tumors.     

Kinetics of a micelle specific palmitoyltransferase isoenzyme of rabbit mammary gland

Palmityl-CoA: monopalmityl-sn-glycerol 3-phosphate palmitoyltransferase [EC 2.3.1. -] in rabbit mammary gland microsomes is composed of two isoenzymic species. The alpha form (LPAT-alpha) is active with monomeric substrates and inhibited by micelles while the beta form (LPAT-beta) is active only with micelles. By combining the effects of time, temperature, and Tween 80 which selectively inhibited LPAT-alpha, the substrate saturation curve for the LPAT-beta isoenzyme has been successfully determined. Both theoretical and experimental curves are in good agreement.     

Lymphocyte subpopulations in the mammary gland of the goat

Mammary glands of pregnant, lactating and resting goats were studied by immunohistochemistry for lymphocyte subpopulations using a panel of monoclonal antibodies. All T lymphocyte subpopulations that may have a role in the immune response, CD2+, CD4+, CD8+ and gamma delta T cells and subsets, were present in the mammary gland and were noted to increase in number progressively during pregnancy, decrease significantly during lactation, and then moderately increase during the resting period. CD4+ cells, the predominant cell type in the mammary gland, were located mainly in the connective tissue, whereas CD2+, CD8+ and TcR1-N24+ cells were predominant in the intraepithelial areas. TcR1-N6+ cells were detected almost exclusively during pregnancy, being localized mainly in the connective tissue. Their proportion decreased markedly following parturition. Very few WC1-N3+ and -N4+ cells were detected in the mammary gland. It is suggested that the majority of gamma delta T lymphocytes in the mammary gland of the goat are CD2+ CD8+ WCl-, a distinctive subset from that of the WCl+ subset in peripheral blood.     

Parathyroid hormone-related protein: a regulated calcium-mobilizing product of the mammary gland

Parathyroid hormone-related protein shares similarities in sequence and function with the endocrine hormone, parathyroid hormone. However, unlike parathyroid hormone, a product of the parathyroid glands, parathyroid hormone-related protein has a wide distribution in tissues, including the mammary gland. Although during pregnancy the expression of parathyroid hormone-related protein in the mammary gland is low, following birth, protein levels rise sharply in the gland in response to elevations in serum prolactin. Large amounts of parathyroid hormone-related protein are secreted into milk, suggesting a possible role in the neonate. Transient phosphaturia and elevations of parathyroid hormone-related protein in mammary vein plasma support a possible endocrine function for parathyroid hormone-related protein during lactation. Recent evidence suggests a local function for parathyroid hormone-related protein in the lactating mammary gland, and evidence exists that parathyroid hormone-related protein stimulates calcium secretion by the goat mammary gland. Parathyroid hormone-related protein, a putative vasodilator, is produced by the external nutrient vasculature of the mammary gland, and levels within this tissue are regulated during lactation. Infusion of parathyroid hormone-related protein into the ovine mammary artery increases gland blood flow, suggesting a role for the protein in modulation of mammary gland hemodynamics. Regulation of parathyroid hormone-related protein synthesis by the lactating gland, together with the protein's actions on regional blood flow and calcium secretion, support an important function in the mammary gland during lactogenesis.     

Human gamma-interferon expression in the mammary gland of transgenic mice

Transgenic mice carrying a hybrid gene consisting of ovine beta-lactoglobulin gene sequences and human gamma-interferon (hIFN-g) cDNA were produced. hIFN-g expression in the mammary gland of two lactating transgenic founder females was found. The concentration of active hIFN-g in the milk was estimated as being ca. 1800 IU/ml. The hIFN-g ability to express in the mammary gland was found in the progeny of transgenic founder male.     

Intracellular behaviour of samarium and europium in lactating mammary gland

The subcellular localization of samarium and europium, two rare-earths, increasingly used in both medical and industrial fields, has been studied in several organs such as liver and kidney but never in the mammary gland despite of its importance in the biology of lactation and nutrition domains. The intracellular behaviour of samarium and europium after their intra-peritoneal administration in the lactating mammary gland cells was investigated. The results showed the presence of very electron dense deposits in the glandular epithelial cell lysosomes. These particular lysosomes were never observed in the mammary cell lysosomes of control rats. These intralysosomal deposits were probably composed of insoluble samarium or europium phosphates by analogy with previous studies, the transmission electron microscopy, the ion mass microscopy and the electron probe microanalysis, and other techniques allowing the identification of the chemical structure of the intralysosomal deposits.     

Telomerase activity in the normal and neoplastic rat mammary gland

The 1-methyl-1-nitrosourea-induced rat mammary tumor model system is well studied, reproducible, and widely used. We have investigated whether these tumors possess higher telomerase activity than normal mammary tissue. Using the telomeric repeat amplification protocol assay, we found significantly higher telomerase activity in 36 mammary carcinomas than in 72 mammary glands of virgin rats. The level of telomerase activity in virgin rats was unaffected by strain, age, stage of the estrous cycle, or ovariectomy. However, mammary glands obtained from pregnant rats exhibited telomerase activity comparable to that found in the tumors, possibly reflecting the high epithelial content of these tissues. Indeed, isolated epithelial cells from virgin and pregnant mammary glands and from carcinomas had similar telomerase activities. Thus, telomerase activity is constitutive in the rat mammary epithelium and is not a unique characteristic of malignant transformation in this tissue. These results underscore the importance of attributing biochemical properties to specific cell types in a tissue, a situation not paralleled in the interpretation of data from in vitro models.     

An entire functional mammary gland may comprise the progeny from a single cell

Any epithelial portion of a normal mouse mammary gland can reproduce an entire functional gland when transplanted into an epithelium-free mammary fat pad. Mouse mammary hyperplasias and tumors are clonal dominant populations and probably represent the progeny of a single transformed cell. Our study provides evidence that single multipotent stem cells positioned throughout the mature fully developed mammary gland have the capacity to produce sufficient differentiated progeny to recapitulate an entire functional gland. Our evidence also demonstrates that these stem cells are self-renewing and are found with undiminished capacities in the newly regenerated gland. We have taken advantage of an experimental model where mouse mammary tumor virus infects mammary epithelial cells and inserts a deoxyribonucleic acid copy(ies) of its genome during replication. The insertions occur randomly within the somatic genome. CzechII mice have no endogenous nucleic acid sequence homology with mouse mammary tumor virus; therefore all viral insertions may be detected by Southern analysis provided a sufficient number of cells contain a specific insertional event. Transplantation of random fragments of infected CzechII mammary gland produced clonal-dominant epithelial populations in epithelium-free mammary fat pads. Serial transplantation of pieces of the clonally derived outgrowths produced second generation glands possessing the same viral insertion sites providing evidence for self-renewal of the original stem cell. Limiting dilution studies with cell cultures derived from third generation clonal outgrowths demonstrated that three multipotent but distinct mammary epithelial progenitors were present in clonally derived mammary epithelial populations. Estimation of the potential number of multipotent epithelial cells that may be evolved from an individual mammary-specific stem cell by self-renewal is in the order of 10(12)-10(13). Therefore, one stem cell might easily account for the renewal of mammary epithelium over several transplant generations.     

Percutaneous bile duct drainage; experiences with a new type of endoprosthesis]

Self expandable stents were placed percutaneously in 105 patients with malignant biliary obstruction. Stent diameter was 1 cm; length, 3.5-10.5 cm. Of the 60 patients with common bile duct obstruction, 50 died 0.2-12 months (median 3 months) after stent insertion. Two patients developed recurrent jaundice and cholangitis after 6 and 12 months, respectively. One patient underwent reintervention. Ten patients, one after a successful reintervention, were alive without jaundice 1-8 months (median 5 months) after stent placement. Of the 45 patients with hilar lesions, 26 died 0.7-18 months (median 5 months) after stent placement, five of them with signs of cholangitis. Nineteen are alive 1-21 months (median 7 months) afterwards. Reinterventions were carried out in 13 patients (29%). The most common cause of stent malfunction was tumour overgrowth. Stent-related complications were seen in three patients.     

Estrogen receptor-negative epithelial cells in mouse mammary gland development and growth

Records of violent behaviour and its sequels gain increasing interest as a matter of quality assurance. The paper presents scales and instruments applied in psychiatric institutions until now. While problems of reliability are solved sufficiently, there are major problems of validity in the measurement of violence. To be usable for quality management, a documentation has to provide a clear cut-off for the severity of violent incidents that should be reported. Otherwise uncomparable data and underreporting will result.     

Morphological experiences with a new bovine carotis xenograft (Solcograft-P) in experimental vascular surgery

The implantation process of the Solcograft-P vascular prosthesis in infrarenal aortic and vena cava inferior positions was studied in dogs in the first 100 postoperative days to investigate its applicability in vascular surgery. The intimal lining was consistently smooth and homogeneous, the problems of aneurysma formation was not serious. Infection and early thrombosis were not more frequent than with other grafts. The impregnated Solcograft-P seemed to be superior to its previous version, the Solcograft. The morphological properties of Solcograft-P seem to make it suitable for venous replacement. The experiments suggested that in selected cases of reconstructive vascular surgery and particularly for patch plastics, Solcograft-P may prove useful.