Connective tissue of rat lung. II: Ultrastructural localization of collagen types III, IV, and VI

We localized collagen types III, IV, and VI in normal rat lung by light and electron immunohistochemistry. Type IV collagen was present in every basement membrane examined and was absent from all other structures. Although types III and VI had a similar distribution, being present in the interstitium of major airways, blood vessels, and alveolar septa, as in other organs, they had different morphologies. Type III collagen formed beaded fibers, 15-20 nm in diameter, whereas type VI collagen formed fine filaments, 5-10 nm in diameter. Both collagen types were found exclusively in the interstitium, often associated with thick (30-35 nm) cross-banded type I collagen fibers. Occasionally, type III fibers and type VI filaments could be found bridging from the interstitium to the adventitial aspect of some basement membranes. Furthermore, the association of collagen type VI with types I and III and basement membranes suggests that type VI may contribute to integration of the various components of the pulmonary extracellular matrix into a functional unit.

Comparative ultrastructural localization of collagen types III, IV, VI and laminin in rat uterus and kidney

Antibodies against collagen types III and VI have been localized by electron immunohistochemistry with two different techniques in normal rat uterus and kidney. Antibodies directed against two components of the extracellular matrix with known localization, laminin and type IV collagen, were used as controls for the specificity of the localization. The results demonstrate that types III and VI are found in the interstitium as fine (10- to 15-nm), beaded fibrils and filaments (6- to 10-nm), respectively. Both are often found associated with thick, crossbanded type I collagen fibers (30- to 35-nm) and occasionally associated with some basement membranes adjacent to the interstitium. Further, the findings suggest that collagens III and VI may connect the various components of the extracellular matrix, such as type I fibers with basement membranes and other structures, thus forming an integrated functional unit.

Properties and purification of a colony-stimulating factor of granulocytes and macrophages produced by mouse spleen cells

Mouse splenocytes are induced by pokeweed mitogen to secrete a factor that stimulates mouse hemopoetic (spelling per Nomina Histologica in the Nomina Anatomica, 5th edition, 1983, Williams and Wilkins, Baltimore) progenitor cells to undergo proliferation and differentiation into granulocytes and macrophages in a semi-solid culture system. The granulocyte and macrophage colony-stimulating factor (GM-CSF) was purified with a four-step procedure that includes ultrafiltration, chromatography on DEAE-agarose, Sephacryl S-200, and chromatofocusing gel. The isoelectric point (pI) of 4.2 of the GM-CSF was determined by analytical isoelectrofocusing gel electrophoresis. The sensitivity of the biological activity of GM-CSF to digestion by trypsin and neuraminidase suggests that GM-CSF is a glycoprotein with its sugar moieties at the active site. The GM-CSF is also sensitive to heat denaturation at 60 degrees C or higher suggesting that a three-dimensional conformation is required for its biological activity. The molecular weight of GM-CSF is approximately 57,000 Daltons as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate.

The extracellular matrix is an integrated unit: ultrastructural localization of collagen types I, III, IV, V, VI, fibronectin, and laminin in human term placenta

The human term placenta is used extensively as a source of extracellular matrix components. To elucidate the tissue distribution and interrelationships of seven of these components, monospecific antibodies directed against collagen types I, III, IV, V, VI, fibronectin, and laminin were reacted with human term placenta and studied by light and electron immunohistochemistry. Type I collagen was the basic structural unit of human term placenta, present as 30-35 nm, cross-banded fibers, often in the form of large fiber bundles. Type III collagen was present as thin 10-15 nm, beaded fibers often forming a meshwork which encased type I collagen fibers. Types V and VI collagen were present as 6-10 nm filaments, often closely associated with types I and III collagen. Type VI collagen also coated collagen fibers of all diameters, enhancing their periodicity, providing a staining pattern often similar to that observed with anti-fibronectin antibodies. Fibronectin was present in both maternal and fetal plasma and throughout the stroma of the chorionic villus, as both free filaments and coating collagen fibers. Basement membranes contained laminin and type IV collagen, but no fibronectin. In summary, the non-basement membrane proteins studied often codistributed with type I collagen, between and apparently attached to fibers, suggesting that they may act as binding proteins, linking type I fibers and bundles, to themselves and to other structures.

Transformation of an AFP-positive yolk sac carcinoma into an AFP-negative neoplasm. Evidence for in vivo cloning of the human parietal yolk sac carcinoma

An alpha-fetoprotein (AFP)-positive ovarian yolk sac carcinoma of typical histologic appearance was surgically removed from a 19-year-old woman. The AFP-positive tumor recurred and was treated with x-rays and cytotoxic drugs to full remission, i.e., until no clinical or biochemical signs of tumor were evident. The second recurrence, which proved to be fatal, was noticed approximately 1 year after the initial diagnosis, but was not associated with elevated levels of serum AFP. At autopsy, the widespread tumor had the histologic appearance reminiscent of murine parietal yolk sac (PYS) carcinoma. The tumor cells did not form the characteristic histologic features of the classical human yolk sac carcinoma, did not secrete AFP, and were surrounded by extensive hyalinous extracellular matrix rich in laminin and collagen. It is thus shown that recurrent human yolk sac carcinomas could change their histologic morphology due to selective outgrowth and cloning of the parietal yolk sac component. Clinical recognition of this cloning is important because the PYS carcinoma cells do not secrete AFP, and the tumor growth cannot be biochemically monitored with this classical tumor marker.

Platelets in renal scleroderma

Electron microscopic findings in a case of suspected scleroderma (progressive systemic sclerosis) showed platelet aggregates within numerous capillary lumens of the kidney. Evidence suggests that platelets may be a factor in the pathogenesis of renal scleroderma.

A small animal model study of perlite and fir bark dust on guinea pig lungs

Fir bark (Abies) and perlite (noncrystalline silicate) dusts have been reported to cause pulmonary disease in humans. Guinea pigs were exposed to either fir bark or perlite dust in a special chamber. Severe pathologic changes occurred in the lungs, consisting of lymphoid aggregated and a perivascular inflammatory response. Both dusts caused similar changes although one was vegetable (fir bark) and the other mineral (perlite). Fir bark and perlite dust appeared to be more than just nuisance dusts.

Deposition of fibronectin and laminin in the basement membrane of the rat parietal yolk sac: immunohistochemical and biosynthetic studies

Rat parietal yolk sacs (PYS) at gestational ages 7.5, 9.5, 11.5, 13.5, 14.5, and 16.5 d were reacted with antibodies against laminin or plasma fibronectin. At all times studied, laminin consistently gave a positive reaction with Reichert's membrane and with the cytoplasm of PYS cells. In contrast, fibronectin gave a negative reaction with Reichert's membrane at day 7.5, was weakly positive at day 9.5, and from then on was increasingly positive with maximum reactivity at 14.5 d. By electron microscopic immunohistochemistry, antilaminin reacted strongly with 14.5-d Reichert's membrane and with the contents of the rough endoplasmic reticulum RER cisternae of the PYS cells. Antifibronectin had some spotty reactivity with Reichert's membrane, but the cytoplasm of the PYS cells was negative. The contents of the vitelline vessels and the interface between trophoblast and Reichert's membrane were strongly positive. Metabolic labeling of PYS cells in organ culture clearly demonstrated the presence of laminin, type IV procollagen, and entactin both in the medium and in tissues, but fibronectin was absent. No component in the medium bound to gelatin-Sepharose columns. These studies demonstrate that PYS cells, which actively synthesize and secrete basement membrane components, do not synthesize any detectable fibronectin. Furthermore, the anti-fibronectin staining pattern in the vitelline vessels and trophoblast-Reichert's membrane interface strongly suggests that the fibronectin present in Reichert's membrane is derived from the maternal circulation and is merely "trapped" in the membrane.

Undifferentiated carcinoma of the colon containing exocrine, neuroendocrine and squamous cells

The light microscopic, electron microscopic and histochemical features of a highly malignant colonic tumor resected from a 39 year old man are presented. The tumor was composed predominantly of undifferentiated cells with focally admixed neuroendocrine, exocrine and squamous cells, occasionally arranged in an organoid manner. Histochemically the tumor contained argyrophilic cells as well as cells that reacted positively with the antibodies to alpha-1-antitrypsin, alpha-1-antichymotrypsin, carcinoembryonic antigen and lysozyme. The term "stem cell carcinoma of the intestine" is proposed for this highly malignant tumor composed of undifferentiated cells exhibiting only focally their multidirectional developmental capacity.

An interferometric analysis of nucleoli in cultured mesothelial cells

Previous studies have indicated that total nucleolar area and volume remain constant regardless of the number of nucleoli. The question remains whether this relationship is valid for mass. To answer this, total nucleolar mass values were obtained from nuclei of living mesothelial cells in culture possessing one to four nucleoli. The nucleolar mass was calculated using interferometry. The mean total nucleolar dry mass for cells with one, two, three, and four nucleoli was 40 x 10(-12)gm, 38.4 x 10(-12)gm, 39.1 x 10(-12)gm, and 41.4 x 10(-12)gm, respectively. These data suggest that on the average, each cell had approximately the same total nucleolar dry mass regardless of the number of nucleoli. In an additional study, interferometry was employed to reveal changes in nucleolar mass and concentration during a seven-hour period. It was concluded that the nucleolus is a dynamic organelle, with its total mass varying in time from an average 40 x 10(-12)gm with a mean concentration of 22.2gm/100cm3.

The soleal line: a cause of tibial pseudoperiostitis

An unusually prominent soleal line (a normal anatomic variant) may mimic periosteal reaction along the posterior margin of the proximal tibial shaft. This area of pseudoperiostitis is differentiated from hyperostoses arising from the anterior tibial tubercle and the interosseous membrane. It is always associated with normal, undisturbed architecture of the underlying bone.