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Biomedical subjects

M Owen

Publications and source records attributed to M Owen.

At least 127 records · Page 7Linked to original sources

Hepatitis B in obstetric patients in the community hospital: the need for screening.

A prospective survey was conducted in a 200-bed community hospital that averages approximately 250 deliveries per month. One hundred consenting obstetric patients were screened for hepatitis B surface antigen (HBsAg). Additionally, hospital physicians were encouraged to order an entire hepatitis serological profile on high-risk obstetric patients, as defined by the Centers for Disease Control; six additional patients were screened by these physicians. Of the 106 patients screened, two (1.9%) were found to have HBsAg. Both were among the six high-risk patients, indicating a 33% prevalence of HBsAg among high-risk obstetric patients and a zero prevalence among low-risk patients. The results appear to support the need for screening of high-risk obstetric patients for hepatitis B. Moreover, vaccination against hepatitis B is advisable for obstetric health-care personnel, who are frequently exposed to blood and extravascular fluids.

Female↗

[Bone formation in bone marrow organ cultures].

Bone tissue composed of typical bone trabeculae containing ground substance with incorporated osteogenic cells and osteoblast layer was formed in organ cultures of bone marrow obtained from adult mice. Electron microscopic properties of the bone formed in vitro were identical to those of the bone tissue in vivo. The mineralization of the bone took place only in the presence of Na-beta-glycerophosphate in the culture medium.

Animals↗

Isolation and properties of recombinant DNA produced variants of human alpha 1-proteinase inhibitor.

Using the glyceraldehyde-3-phosphate dehydrogenase promoter, nonglycosylated human alpha 1-proteinase inhibitor, representing 10% of the soluble cell protein, has been synthesized in yeast. Two forms of this protein were isolated with one being analogous to the human plasma protein and the other having the amino acid valine replacing methionine at position 358 (the P1 position). Both proteins were more sensitive to heat inactivation than the plasma form, and both had shorter half-lives in rabbits. These differences were presumably due to the absence of carbohydrate. Each protein could bind neutrophil elastase at a rate only slightly slower than that of human plasma alpha 1-proteinase inhibitor. However, the valine variant was stable to oxidation, while the P1 methionine-containing protein was readily inactivated. The specificity of alpha 1-proteinase inhibitor (methionine) was identical to that of the plasma form; however, the valine form could only effectively bind to neutrophil or pancreatic elastase, "trypsin-like" serine proteinases not being inactivated at all. These data indicate the potential importance of mutant forms of proteinase inhibitors, produced by recombinant DNA technology, as therapeutic agents for the inactivation of excess proteinases of a specific type in tissues.

Blood Proteins↗

Middle meningeal artery trauma.

We present the case of a patient who had the symptoms of a subarachnoid hemorrhage but was subsequently found to have an unusual combination of a separate traumatic pseudoaneurysm and a traumatic arteriovenous fistula of the middle meningeal artery. A review of the literature revealed a difference in the clinical course of patients with traumatic pseudoaneurysms compared to that of patients with arteriovenous fistulas. Patients who were found to have traumatic pseudoaneurysms of the middle meningeal artery frequently manifested signs of delayed hemorrhage. This mechanism may account for the prolonged lucid intervals exhibited in some patients subsequently found to have epidural hematomas.

Arteriovenous Fistula↗

Parents as partners.

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Child Health Services↗

Giant liposarcoma of the spermatic cord.

Liposarcoma of the spermatic cord is rare and easily masquerades as a more common benign neoplasm of the spermatic cord. If neglected, these malignancies may grow to tremendous size and become formidable management problems. The treatment of this malignancy is orchiectomy and en bloc removal of the tumor. More radical operative therapy has not generally proved beneficial. Adjunctive therapy may be helpful in selected cases.

Genital Neoplasms, Male↗

Studies on the concentration and intracellular localization of iron proteins in liver biopsy specimens from patients with iron overload with special reference to their role in lysosomal disruption.

Liver biopsies were collected from control subjects and patients with iron overload due to either primary or secondary haemochromatosis. They were analysed for iron proteins by cation exchange chromatography and flameless atomic absorption spectrophotometry. In control tissue the transferrin fraction contains 25%, ferritin 50% and haemprotein and haemosiderin 10--15% each, of the total iron. In iron overloaded tissue the ferritin and haemosiderin iron increases approximately 10- and 100-fold, respectively, compared with control tissue. There was a close positive correlation between enhanced lysosomal fragility as determined by measurements of latent N-acetyl-beta-glucosaminidase and haemosiderin content of the tissue; it is suggested that the haemosiderin is responsible for the lysosomal disruption and hence the tissue damage in iron overload. Studies were performed on the intracellular localization of ferritin and of total iron in biopsy extracts from control subjects and from patients with iron overload. In control tissue, ferritin contains most of the iron and is apparently free in the cytosol. In iron overload, ferritin is the major iron protein in the post-nuclear supernatant sedimenting into the gradient as the free protein. There are, however, significant amounts of immunoreactive ferritin deeper in the gradients but this cannot be assigned to any particular subcellular organelle. The extreme fragility of lysosomes in iron overloaded human tissue makes isolation of these organelles for detailed biochemical analysis extremely difficult.

Acetylglucosaminidase↗

Formation of bone and cartilage by marrow stromal cells in diffusion chambers in vivo.

When freshly isolated rabbit marrow cells were cultured either in vitro or in diffusion chambers in vivo, the hemopoietic cells disappeared and there was a proliferation of the stromal cell population. The colonies formed in vitro were mainly fibroblastic, and this cell type predominated in confluent cultures. Staining for alkaline phosphatase activity and for the Von Kossa reaction was negative in in vitro cultures. However, marrow cell suspensions or fibroblasts harvested from in vitro culture of marrow cells, gave rise to a mixture of bone, cartilage and fibrous tissue in diffusion chambers implanted into the peritoneal cavity. In contrast, only a soft fibrous tissue developed from spleen fibroblasts in diffusion chambers. Differentiation of osteogenic tissue within diffusion chambers fell into two categories: (1) Formation of bone in a fibrous layer surrounding cartilage; (2) intramembranous bone formed directly within fibrous tissue unassociated with cartilage. In both cases alkaline phosphatase activity appeared before the onset of mineralization, and decreased as the first signs of mineral became apparent. The present results suggest that postnatal marrow contains osteogenic precursors with the potential to differentiate via either of the two major paths followed during skeletal development in the embryo. Clonal analysis of the marrow stromal cell population will be required to clarify whether osteo-, chondro-, and fibrogenic cells are the products of one stromal cell line modulated by the microenvironment, or whether there are distinct cell lines for each type.

Alkaline Phosphatase↗