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Biomedical subjects

C C Daugherty

Publications and source records attributed to C C Daugherty.

At least 19 recordsLinked to original sources
PubMed2001

Wound-healing defects in mice lacking fibrinogen.

In addition to its key role in the control of blood loss following injury, fibrin(ogen) has been proposed to play an important role in tissue repair by providing an initial matrix that can stabilize wound fields and support local cell proliferation and migration. To test directly these concepts, the effect of fibrinogen deficiency on cutaneous tissue repair in mice was investigated using incisional and excisional wounds. The time required to overtly heal wounds was similar in fibrinogen-deficient and control mice, but histologic evaluation revealed distinct differences in the repair process, including an altered pattern of epithelial cell migration and increased epithelial hyperplasia. Furthermore, granulation tissue in fibrinogen-deficient mice failed to adequately close the wound gap, resulting in persistent open wounds or partially covered sinus tracts. The tensile strength of these wounds was also reduced compared with control mice. The most profound defect in wound tissue organization was observed in fibrinogen-deficient mice following the subcutaneous implantation of a porous tubing chamber. Cells migrated into the wall of the implants at a similar rate as control mice, but cells from fibrinogen-deficient animals were unable to efficiently organize and migrate into wound fluid-filled dead space within the center of the implants. These studies show that re-epithelialization, granulation tissue formation, including the establishment of neovasculature, and the formation of fibrotic scar tissue can proceed in the absence of fibrin(ogen) and all of its proteolytic derivatives. However, fibrin (ogen) is important for appropriate cellular migration and organization within wound fields and in initially establishing wound strength and stability. (Blood. 2001;97:3691-3698)

Animals↗
PubMed1998

Ligneous conjunctivitis in plasminogen-deficient mice.

Ligneous conjunctivitis is a rare form of chronic pseudomembranous conjunctivitis that is associated with systemic membranous pathological changes. A probable link between plasminogen and ligneous conjunctivitis has been indicated by the recent diagnoses of plasminogen deficiency in five patients suffering from ligneous conjunctivitis. The current study reports that plasminogen-deficient mice develop conjunctival lesions indistinguishable from human ligneous conjunctivitis in both appearance and histology. Both human and mouse lesions contain acellular material rich in fibrin, and aberrant or disrupted epithelium. The incidence of lesion development in mice increases with age and is strongly influenced by genetic background. Interestingly, ligneous conjunctivitis was not observed in plasminogen-deficient mice simultaneously lacking fibrinogen. This study provides direct evidence that plasminogen deficiency is one cause of ligneous conjunctivitis and suggests that plasminogen-deficient mice may be an excellent model for the development of therapeutic strategies for the treatment of this debilitating disease.

Aging↗
PubMed1997

Growth and dissemination of Lewis lung carcinoma in plasminogen-deficient mice.

Plasminogen activation has been proposed to play a critical role in cancer invasion and metastasis. The effects of complete ablation of plasminogen activation in cancer was studied by inoculation of a metastatic Lewis lung carcinoma expressing high levels of plasminogen activator into plasminogen-deficient (Plg-/-) mice and matched control mice. Primary tumors developed in all mice with no difference in the rate of appearance between Plg-/- and control mice. However, the primary tumors in Plg-/- mice were smaller and less hemorrhagic and displayed reduced skin ulceration. In addition, dissemination of the tumor to regional lymph nodes was delayed in Plg-/- mice. Surprisingly, no quantitative differences were observed in lung metastasis between Plg-/- and control mice. In addition, Plg deficiency was compatible with metastasis of the primary tumor to a variety of other organs. Nevertheless, Plg-/- mice displayed a moderately increased survival after primary tumor resection. These findings suggest that plasmin-mediated proteolysis contributes to the morbidity and mortality of Lewis lung carcinoma in mice, but sufficient proteolytic activity is generated in Plg-/- mice for efficient tumor development and metastasis.

Animals↗
PubMed1996

Loss of fibrinogen rescues mice from the pleiotropic effects of plasminogen deficiency.

Plasmin(ogen) is an extracellular serine protease implicated in the activation of latent growth factors and procollagenase, degradation of extracellular matrix components, and fibrin clearance. Plasminogen (Plg) deficiency in mice results in high mortality, wasting, spontaneous gastrointestinal ulceration, rectal prolapse, and severe thrombosis. Furthermore, Plg-deficient mice display delayed wound healing following skin injury, a defect partly related to impaired keratinocyte migration. We generated mice deficient in Plg and fibrinogen (Fib) and show that removal of fibrin(ogen) from the extracellular environment alleviates the diverse spontaneous pathologies previously associated with Plg deficiency and corrects healing times. Mice deficient in Plg and Fib are phenotypically indistinguishable from Fib-deficient mice. These data suggest that the fundamental and possibly only essential physiological role of Plg is fibrinolysis.

Afibrinogenemia↗
PubMed1996

Impaired platelet aggregation and sustained bleeding in mice lacking the fibrinogen motif bound by integrin alpha IIb beta 3.

Blood loss at sites of vascular rupture is controlled by the adhesion and aggregation of platelets and the formation of an insoluble fibrin matrix. Fibrinogen is considered to be critical in these processes by both providing an abundant dimeric ligand for alpha IIb beta 3-mediated platelet aggregation, and serving as the fundamental building block of the fibrin polymer. To establish an in vivo model system to examine in detail the importance of alpha IIb beta 3-fibrinogen interactions in platelet function, hemostasis, response to injury and vasoocclusive disease, and to test the prevailing hypothesis that the C-terminal segment of the fibrinogen gamma chain is essential for alpha IIb beta 3 binding, we have used gene-targeting technology in mice to eliminate the last five residues (QAGDV) from the gamma chain. Mice homozygous for the modified gamma chain gene (gamma delta 5/gamma delta 5) displayed a generally normal hematological profile, including normal platelet count, plasma fibrinogen level, clotting time and fibrin crosslinking. However, both gamma delta 5-fibrinogen binding to alpha IIb beta 3 and platelet aggregation were highly defective. Remarkably, another alpha IIb beta 3-dependent process, clot retraction, was unaffected by the gamma delta 5 mutation. Despite the preservation of clotting function, gamma delta 5/gamma delta 5 mice were unable to control blood loss following a surgical challenge and occasionally developed fatal neonatal bleeding events.

Amino Acid Sequence↗
PubMed1996

Urokinase-type plasminogen activator is effective in fibrin clearance in the absence of its receptor or tissue-type plasminogen activator.

The availability of gene-targeted mice deficient in the urokinase-type plasminogen activator (uPA), urokinase receptor (uPAR), tissue-type plasminogen activator (tPA), and plasminogen permits a critical, genetic-based analysis of the physiological and pathological roles of the two mammalian plasminogen activators. We report a comparative study of animals with individual and combined deficits in uPAR and tPA and show that these proteins are complementary fibrinolytic factors in mice. Sinusoidal fibrin deposits are found within the livers of nearly all adult mice examined with a dual deficiency in uPAR and tPA, whereas fibrin deposits are never found in livers collected from animals lacking uPAR and rarely detected in animals lacking tPA alone. This is the first demonstration that uPAR has a physiological role in fibrinolysis. However, uPAR-/-/tPA-/- mice do not develop the pervasive, multi-organ fibrin deposits, severe tissue damage, reduced fertility, and high morbidity and mortality observed in mice with a combined deficiency in tPA and the uPAR ligand, uPA. Furthermore, uPAR-/-/tPA-/- mice do not exhibit the profound impairment in wound repair seen in uPA-/-/tPA-/- mice when they are challenged with a full-thickness skin incision. These results indicate that plasminogen activation focused at the cell surface by uPAR is important in fibrin surveillance in the liver, but that uPA supplies sufficient fibrinolytic potential to clear fibrin deposits from most tissues and support wound healing without the benefit of either uPAR or tPA.

Animals↗
PubMed1995

Resolution of spontaneous bleeding events but failure of pregnancy in fibrinogen-deficient mice.

To explore the role of the key coagulation factor, fibrinogen, in development, hemostasis, wound repair, and disease pathogenesis, we disrupted the fibrinogen A alpha chain gene in mice. Homozygous, A alpha chain-deficient (A alpha-/-) mice are born normal in appearance, and there is no evidence of fetal loss of these animals based on the Mendelian pattern of transmission of the mutant A alpha chain allele. All of the component chains of fibrinogen (A alpha, B beta, and gamma) are immunologically undetectable in the circulation of both neonatal and adult A alpha-/- mice, and blood samples fail to either clot or support platelet aggregation in vitro. Overt bleeding events develop shortly after birth in approximately 30% of A alpha-/- mice, most frequently in the peritoneal cavity, skin, and soft tissues around joints. Remarkably, most newborns displaying signs of bleeding ultimately control the loss of blood, clear the affected tissues, and survive the neonatal period. Juveniles and young adult A alpha-/- mice are predisposed to spontaneous fatal abdominal hemorrhage, but long-term survival is variable and highly dependent on genetic background. The periodic rupture of ovarian follicles in breeding-age A alpha-/- females does not appear to significantly diminish life expectancy relative to males; however, pregnancy uniformly results in fatal uterine bleeding around the tenth day of gestation. Microscopic analysis of spontaneous lesions found in A alpha-/- mice suggests that fibrin(ogen) plays a fundamental role in the organization of cells at sites of injury.

Afibrinogenemia↗
PubMed1995

The receptor for urokinase-type plasminogen activator is not essential for mouse development or fertility.

The urokinase-type plasminogen activator receptor (uPAR) gene was disrupted in mice in order to explore the role of cell surface-associated plasminogen activation in development and hemostasis. Homozygous, uPAR-/- mice were born and survived to adulthood with no overt phenotypic abnormalities. There was no indication of loss of fetal animals based on the Mendelian pattern of transmission of the mutant uPAR gene. uPAR-/- mice carried no detectable uPAR in lung, spleen, and other tissues when measured both immunologically by Western blot analysis and functionally by ligand cross-linking analyses. In addition, activated peritoneal macrophages collected from uPAR-/- mice failed to promote plasminogen activation in vitro. The loss of the receptor also resulted in a redistribution of uPA in some tissues but had no impact on pro-uPA activation in the urogenital tract. Thus, in the absence of other challenging factors such as infection, injury, or other functional deficits, uPAR deficiency does not compromise fertility, development, or hemostasis. These mice provide a means to test the proposed function of uPA/uPAR in wound repair, atherogenesis, and tumor cell invasion in vivo.

Animals↗
PubMed1995

Plasminogen deficiency causes severe thrombosis but is compatible with development and reproduction.

Plasminogen (Plg)-deficient mice were generated to define the physiological roles of this key fibrinolytic protein and its proteolytic derivatives, plasmin and angiostatin, in development, hemostasis, and reproduction. Plg-/- mice complete embryonic development, survive to adulthood, and are fertile. There is no evidence of fetal loss of Plg-/- mice based on the Mendelian pattern of transmission of the mutant Plg allele. Furthermore, embryonic development continues to term in the absence of endogenous, sibling-derived, or maternal Plg. However, Plg-/- mice are predisposed to severe thrombosis, and young animals developed multiple spontaneous thrombotic lesions in liver, stomach, colon, rectum, lung, pancreas, and other tissues. Fibrin deposition in the liver was a uniform finding in 5- to 21-week-old mice, and ulcerated lesions in the gastrointestinal tract and rectal tissue were common. A remarkable finding, considering the well-established linkage between plasmin and the proteolytic activation of plasminogen activators, was that the level of active urokinase-type plasminogen activator in urine was unaffected in Plg-/- mice. Therefore, Plg plays a pivotal role in fibrinolysis and hemostasis but is not essential for urokinase proenzyme activation, development, or growth to sexual maturity.

Angiostatins↗
PubMed1994

MR imaging of biliary cysts in children with biliary atresia: clinical associations and pathologic correlation.

OBJECTIVE: We used MR imaging to determine the prevalence of biliary cysts in children with end-stage biliary atresia and evaluated the association of cysts with cholangitis, choleretic therapy, portoenterostomy, biochemical abnormalities, and MR findings of end-stage liver disease. The MR features of these cysts were correlated with their gross and histopathologic appearances. MATERIALS AND METHODS: We retrospectively reviewed 48 MR studies, clinical history, and laboratory data of 44 consecutive children with biliary atresia. RESULTS: MR images showed cysts in eight patients (18%). Cysts were statistically (p < .04) more common in patients who had a history of cholangitis, but were not associated with choleretic therapy or portoenterostomy surgery. Cysts were not statistically correlated with abnormalities in hepatic biochemical function or MR features of end-stage liver disease. Four livers with cysts were available for histopathologic study. Cysts were filled with bile, and most had an epithelial lining, consistent with a biliary origin. The epithelium was frequently ulcerated, accompanied by periportal extravasation of bile and inflammation. These findings suggest chronic obstruction with microscopic perforation. CONCLUSION: Biliary cysts are common in biliary atresia and may be related to previous episodes of cholangitis with attendant obstruction of biliary radicles. The presence of these cysts did not correlate with hepatic function, portoenterostomy surgery, or the extent of liver disease.

Bile Duct Diseases↗
PubMed1993

John Caffey Award. Colonic perforation by air and liquid enemas: comparison study in young pigs.

OBJECTIVE: Hydrostatic enema reduction of intussusception in children has been replaced by pneumatic reduction in a number of institutions. Colonic perforation occurs in as many as 2.8% of enema reductions, and questions persist about the relative safety of enemas performed with air vs fluid. The objectives of this study were to investigate and compare the pathologic patterns of in vivo colonic perforation and fecal spillage in young pigs given air and hydrostatic enemas, with and without the Valsalva maneuver. MATERIALS AND METHODS: Colonic perforations were induced in 135 juvenile pigs. The pigs were divided into five groups, and enemas with air, barium, and water-soluble contrast material were given with and without the Valsalva maneuver to induce the perforations. During the enemas, the Valsalva maneuver was observed when the animals strained. In each animal, the enema was continued and pressure increased until a perforation was detected with fluoroscopy. Radiographic, gross, and histologic examinations of each animal were performed after perforations occurred. Differences in fecal spillage were noted, and the morphologic variations of the perforations and the surrounding tissue were determined. RESULTS: Perforations with hydrostatic (barium, water-soluble) enemas occurred at approximately 120 mm Hg of pressure (average bag height, 57 in. [143 cm]). No significant variations were found between the type of material used for contrast or the use of the Valsalva maneuver. With air enemas, perforations occurred at a mean pressure of 108 mm Hg without the Valsalva maneuver and at 145 mm Hg with the Valsalva maneuver. Perforations during air enemas did not occur during the Valsalva maneuver (pressures as high as 270 mm Hg), but rather between Valsalva maneuvers. Hydrostatic enemas produced full-thickness tears that were larger than those induced by air enemas in all cases. Air enemas with and without the Valsalva maneuver produced partial-thickness tears in 45% and 10%, respectively, of the pigs. Fecal spillage was diffuse in all hydrostatic perforations. In air enemas, spillage was focal in 55% and 90%, respectively, and absent in 45% and 10%, respectively, of perforations produced with and without the Valsalva maneuver. CONCLUSION: Our results suggest that air enemas are safer than liquid enemas. Perforations that occurred during air enemas were smaller and associated with less fecal spillage and peritoneal contamination. The Valsalva maneuver appears to prevent colonic perforation during air enemas.

Animals↗
PubMed1993

Resolution of liver biopsy alterations in three siblings with bile acid treatment of an inborn error of bile acid metabolism (delta 4-3-oxosteroid 5 beta-reductase deficiency).

Identical male twins and their brother, cholestatic from birth, with delta 4-3-oxosteroid 5 beta-reductase deficiency, were studied by serial liver biopsy. Spectrometry documented defective primary bile acid synthesis and markedly increased levels of atypical oxo and allo bile acids in urine and serum. Hepatocellular cholestasis and giant-cell transformation resolved in parallel with clinical and biochemical recovery during oral bile acid administration. In the twins, portal fibrosis stabilized at a mild level; they are well as 5-yr-olds at this writing. Follow-up biopsy in their brother at 8 mo was normal, and he is doing well at 3 yr of age. Hepatic ultrastructural alterations in all three were characterized by abnormalities of bile canaliculi including small bile plugs, diverticulae and latticelike elaborations of hepatocellular membranes adjacent to bile canaliculi that were shown to have resolved completely on subsequent biopsies. Eight additional cases have been detected on urine screening; only two of these patients have survived, on bile acid therapy. Early diagnosis and treatment improves the prognosis of this otherwise lethal inborn error of bile acid synthesis.

Bile Acids and Salts↗
PubMed1991

Complete hepatic regeneration after somatic deletion of an albumin-plasminogen activator transgene.

We previously demonstrated that expression of an albumin-urokinase-type plasminogen activator (Alb-uPA) fusion construct in transgenic mice resulted in elevated plasma uPA concentration, hypofibrinogenemia, and neonatal hemorrhaging. Two lines of Alb-uPA mice were established in which only one half of the transgenic pups died at birth; surprisingly, plasma uPA concentrations in survivors gradually returned to normal by 2 months of age. The basis for this phenomenon is DNA rearrangement within hepatocytes that affects the transgene tandem array and abolishes transgene expression. Transgene-deficient cells selectively proliferate relative to surrounding liver, and this process culminates in replacement of the entire liver by clonal hepatic nodules derived from transgene-deficient progenitor cells. In some cases as few as two nodules can reconstitute over 90% of liver mass, highlighting the remarkable regenerative capacity of individual liver cells.

Animals↗
PubMed1991

The internal carotid artery siphon in children and adolescents.

We observed significant lesions of the carotid artery siphon in two young subjects with fatal stroke. Because stroke in children and adolescents is uncommon and poorly understood, we examined the internal carotid artery in the 'siphon' of the skull in 24 unselected, but nearly consecutive autopsies. The age range was 10 days to 38 years, with 11 males and 13 females, six blacks, and 18 whites. In no case was stroke the cause of death. Intimal lesions of two types were found in the carotid siphon of all cases. (1) The first was focal splitting and/or duplication of the internal elastic lamina with variable proliferation of smooth muscle. The resulting 'fibrous' plaques or cushions, when severe, were usually found at natural bends in the artery. The number and severity of this type of lesion increased with age, but there were no differences in severity or distribution when compared by sex, race, or mode of death. (2) The second was internal elastic calcification which was found in all cases older than 9. This was increasingly severe with age. Although the frequency of the vascular lesions was surprisingly high, the relationship of either type to dissecting aneurysm or other stroke lesion remains unclear.

Adolescent↗
PubMed1990

Cis-acting sequences from a human surfactant protein gene confer pulmonary-specific gene expression in transgenic mice.

Pulmonary surfactant is produced in late gestation by developing type II epithelial cells lining the alveolar epithelium of the lung. Lack of surfactant at birth is associated with respiratory distress syndrome in premature infants. Surfactant protein C (SP-C) is a highly hydrophobic peptide isolated from pulmonary tissue that enhances the biophysical activity of surfactant phospholipids. Like surfactant phospholipid, SP-C is produced by epithelial cells in the distal respiratory epithelium, and its expression increases during the latter part of gestation. A chimeric gene containing 3.6 kilobases of the promoter and 5'-flanking sequences of the human SP-C gene was used to express diphtheria toxin A. The SP-C-diphtheria toxin A fusion gene was injected into fertilized mouse eggs to produce transgenic mice. Affected mice developed respiratory failure in the immediate postnatal period. Morphologic analysis of lungs from affected pups showed variable but severe cellular injury confined to pulmonary tissues. Ultrastructural changes consistent with cell death and injury were prominent in the distal respiratory epithelium. Proximal components of the tracheobronchial tree were not severely affected. Transgenic animals were of normal size at birth, and structural abnormalities were not detected in nonpulmonary tissues. Lung-specific diphtheria toxin A expression controlled by the human SP-C gene injured type II epithelial cells and caused extensive necrosis of the distal respiratory epithelium. The absence of type I epithelial cells in the most severely affected transgenic animals supports the concept that developing type II cells serve as precursors to type I epithelial cells.

Animals↗
PubMed1989

Electron microscopy in the diagnosis of pediatric disease.

Electron microscopy, although not able to solve all diagnostic dilemmas, is an essential adjunct to the analysis of pathologic processes. The importance of correct specimen handling for ultrastructural study is highlighted. Some diseases encountered in pediatrics, in which the ultrastructural findings are well established, are illustrated. New technologies that show promise for wider application to problems in pathology also are considered in this article.

Child↗
PubMed1987

A morphometric study of Reye's syndrome. Correlation of reduced mitochondrial numbers and increased mitochondrial size with clinical manifestations.

Morphometric analysis of liver ultrastructure in 14 children with Reye's syndrome (RS) of varying morphologic severity was compared with that of 6 children with normal livers. Results showed reduced numbers of enlarged mitochondria in RS. Multivariant analysis identified correlations between increased mitochondrial size, decreased mitochondrial number, and severity of neurologic disease (stage). A disproportionate increase in mitochondrial area and perimeter in the RS cases with the most depressed mitochondrial number distinguished the 4 children with residual neurologic damage or death. Serum salicylate concentrations were negatively correlated with severity of morphologic alteration. Two cases of non-RS salicylate toxicity showed normal or near-normal mitochondrial size and number. In fatty liver from an autopsy specimen from a child, a child with carnitine deficiency, and a child on therapy for dermatomyositis, mitochondrial numbers were also normal. Decreased mitochondrial numbers are characteristic of RS and imply a pathophysiologic mechanism, possibly related to impaired mitochondrial replication. Synergism with other forms of mitochondrial injury, such as salicylates, hypoglycemia, or shock may influence clinical severity, progression, and outcome.

Analysis of Variance↗