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Biomedical subjects

I D Young

Publications and source records attributed to I D Young.

At least 73 records · Page 4Linked to original sources
PubMed1993

Synthesis of digoxigenin-labeled cRNA probes for nonisotopic in situ hybridization using reverse transcription polymerase chain reaction.

Nonisotopic methods of mRNA in situ hybridization have distinct advantages over isotopic techniques. Nonisotopically labeled probes are stable and nontoxic, have short detection times, demonstrate excellent spatial resolution of their signals and have sensitivities comparable to radiolabeled probes. We developed a simple method of generating nonisotopically labeled cRNA probes which is based on the reverse transcription polymerase chain reaction (RT-PCR) and used it to synthesize a panel of probes for various murine extracellular matrix genes. Engelbreth-Holm-Swarm (EHS) tumor RNA was reverse transcribed and PCR was used to amplify defined regions of multiple extracellular matrix protein genes from the resulting first strand cDNAs. Bacteriophage promoters which had been incorporated into the PCR products were then used to generate digoxigenin-conjugated antisense and sense cRNAs. The antisense probes were employed to detect the specific extracellular matrix protein mRNAs in the EHS tumor by in situ hybridization. This technique provides a rapid and efficient alternative to conventional transcription systems which use plasmid vectors for the synthesis of digoxigenin-labeled cRNA probes.

Animals↗
PubMed1993

Immunohistochemical analysis of type IV collagenase expression in prostatic hyperplasia and adenocarcinoma.

The 72-kDa Type IV collagenase (T4C) is a matrix metalloproteinase, the expression of which may be important in normal basement membrane metabolism. The production of T4C by malignant cells has been linked to their invasive and metastatic potential in several tumor systems. The pattern of T4C immunoreactivity was assessed in formalin-fixed, paraffin-embedded prostatic tissue using polyclonal, monospecific antibodies. Basal cells in normal and hyperplastic epithelium demonstrated slight to moderate cytoplasmic immunoreactivity, while secretory epithelial cells showed generally weaker immunostaining. In 35 of 35 cases of primary adenocarcinoma and five of five cases of metastatic adenocarcinoma in lymph nodes, the majority of malignant cells showed strong immunoreactivity. Similar strong immunostaining was also seen in foci of prostatic intraepithelial neoplasia. The high level of expression of T4C in prostatic adenocarcinoma and its metastases suggests this metalloproteinase may play a role in determining the invasive and metastatic properties of this tumor. The enhanced immunoreactivity in prostatic intraepithelial neoplasia suggests the induction of T4C may be an early event in the development of the invasive phenotype. The expression of T4C in benign epithelial cells may be a manifestation of its putative physiological role in basement membrane metabolism.

Adenocarcinoma↗
PubMed1993

Induction of perlecan gene expression precedes amyloid formation during experimental murine AA amyloidogenesis.

BACKGROUND: In a murine model of AA amyloidosis, it has been demonstrated that perlecan, the basement membrane heparan sulfate proteoglycan, is co-deposited with AA amyloid as it forms in various tissues. The objectives of this study were to determine whether the accumulation of perlecan during amyloidogenesis is associated with induction of perlecan gene expression and, if so, to define the temporal relationship of this induction to the onset of amyloid formation. EXPERIMENTAL DESIGN: Accelerated splenic AA amyloidosis was stimulated in mice by concomitant administration of subcutaneous silver nitrate as an inflammatory stimulus and amyloid-enhancing factor. A kinetic analysis of splenic perlecan mRNA levels during amyloid formation in the spleen was conducted using a reverse transcription-polymerase chain reaction assay. Amyloid deposits were detected histochemically with the Congo red stain and by immunohistochemistry using anti-AA antisera. RESULTS: Perlecan mRNA levels increased significantly during amyloidogenesis, increasing 4.1-fold within 72 hours of the amyloidogenic stimulus and subsequently falling to steady-state levels. A 2.0-fold induction of perlecan mRNA occurred by 24 hours post-stimulation, a time at which amyloid was not detectable by either histochemistry or immunohistochemistry. In contrast, control animals administered either the inflammatory stimulus or AEF alone showed no significant change in perlecan mRNA levels. CONCLUSIONS: Increased perlecan mRNA levels account, at least in part, for the accumulation of perlecan in murine splenic AA amyloid deposits. This induction of perlecan gene expression occurs before the onset of amyloid formation, supporting a role for perlecan in the earliest stages of amyloid fibrillogenesis.

Amyloid↗
PubMed1993

New syndrome with features overlapping the Baller-Gerold and Roberts syndromes.

A male fetus is described with multiple congenital abnormalities including craniosynostosis and bilateral radial aplasia. There are many similarities to the case recently reported by Imaizumi and Kuroki (Am J Med Genet 41: 162-163). These cases may represent a new syndrome with overlapping features of the Baller-Gerold and Roberts syndromes.

Abnormalities, Multiple↗
PubMed1993

Dominant inheritance of microcephaly, short stature and congenital dislocation of the hips.

A family showing dominant inheritance of microcephaly, short stature, congenital dislocation of the hips and dysmorphic features is described. Affected individuals have malar hypoplasia, prominent nasal root, beaked nose, short philtrum and simple ears. This facial appearance is very similar to that in the family reported by Bawle and Horton in 1989.

Abnormalities, Multiple↗
PubMed1992

The pathogenesis of nodular regenerative hyperplasia of the liver associated with rheumatoid vasculitis.

Nodular regenerative hyperplasia (NRH) is an uncommon liver disease that typically develops in the setting of a chronic illness such as Felty's syndrome. Although the pathogenesis of NRH has not been defined, vasculitis has been postulated to play an important pathogenetic role in some cases of NRH, even though the association of NRH and vasculitis has been reported rarely. We describe two unusual cases of NRH in patients with Felty's syndrome complicated by rheumatoid vasculitis. Morphometric analysis demonstrated evidence of injury to the hepatic vasculature in the form of loss of small intrahepatic arteries and portal spaces, findings that support the hypothesis that hepatic arteritis plays a role in the development of NRH in cases associated with systemic vasculitis.

Adult↗
PubMed1992

Lethal olivopontoneocerebellar hypoplasia with dysmorphic features in sibs.

This report describes the clinical and neuropathological features in male and female sibs who died shortly after birth as a result of frequent convulsions and lack of spontaneous respiratory effect. Both sibs had a prominent occiput with mild contractures and the female also had overlapping fingers and rockerbottom feet. The genetic and neuropathological findings were consistent with a diagnosis of an autosomal recessive form of olivopontoneocerebellar hypoplasia/atrophy.

Abnormalities, Multiple↗
PubMed1992

Campomelic dysplasia associated with a de novo 2q;17q reciprocal translocation.

A phenotypically female fetus with campomelic dysplasia and a de novo reciprocal translocation, 46,XY,t(2;17) (q35;q23-24), is presented. This is the second case of campomelic dysplasia in which a rearrangement involving the long arm of chromosome 17 has been identified, indicating that this is likely to be the site of the campomelic dysplasia locus.

Abnormalities, Multiple↗
PubMed1992

A critical analysis of postulated pathogenetic mechanisms in amyloidogenesis.

This review has examined several of the major thrusts in amyloid research, past and present. The data concerning amyloid precursor quantity, primary protein and gene structure, and precursor proteolysis have shown that there are contradictions that must be resolved before these elements can be reamalgamated into a unified view of amyloidogenesis. One possibility is presented in Figure 2. A general hypothesis of amyloid formation that accounts for the uniformity of fibril structure, amyloid staining properties, and the specific selection of precursors and their specific anatomic localization in each form of amyloid has yet to be proposed. Some of these questions may be answered by an analysis of common structural constituents in amyloid deposits. Analyzing amyloid generation in the context of these common elements separates amyloid research into several specific areas (Figure 2). The first area concerns factors that govern the expression of amyloid precursor protein genes, thus providing adequate quantities of the precursor, if such a precursor pool does not already exist. Without such a pool, amyloid deposition clearly cannot occur. The second area concerns information as to where these precursors usually bind and/or exert their normal function. Once determined, this information will likely indicate the site or sites where the particular precursor may give rise to amyloid deposits. The last area concerns factors at these local sites that govern the interaction of the precursor with basement membrane or related extracellular matrix elements that would define both the site and the final common pathway for amyloid deposition.

Amyloid↗
PubMed1992

Trisomy/partial monosomy 13 mosaicism associated with relatively mild clinical malformation.

A female fetus with a rare de novo chromosome abnormality involving mosaicism with two cell lines with trisomy 13 and presumptive partial monosomy 13 due to a Robertsonian translocation and ring chromosome, respectively, was prenatally diagnosed. On termination this case, together with apparently the only other three reported cytogenetically similar cases, was found to have much less severe clinical abnormalities than might have been predicted. The possibility in these cases that the effects of the trisomy and monosomy for the common segment of chromosome 13 may have counterbalanced each other at the tissue level in embryogenesis thereby resulting in less disturbance of morphogenesis than would be expected for each type of imbalance acting in isolation is considered.

Abnormalities, Multiple↗
PubMed1992

Localization of the basement membrane heparan sulfate proteoglycan in islet amyloid deposits in type II diabetes mellitus.

Amyloid in the islets of Langerhans is the uniform pathologic feature in the pancreata of patients with type II diabetes mellitus. Although the mechanisms of islet amyloid fibrillogenesis are unknown, the presence of heparan sulfate proteoglycan in many other forms of amyloid suggests a role for this proteoglycan in amyloidogenesis in general. In this study, islet amyloid was evaluated for the presence of the basement membrane heparan sulfate proteoglycan using histochemical and immunohistochemical techniques. Staining with sodium sulfate-alcian blue identified highly sulfated glycosaminoglycans within all islet amyloid deposits, and anti-basement membrane heparan sulfate proteoglycan antisera localized this specific proteoglycan within the islet amyloid. The presence of the basement membrane heparan sulfate proteoglycan links islet amyloid to other disparate forms of amyloid and further supports the hypothesis that it has a role in a common pathway of amyloid fibrillogenesis.

Amyloid↗
PubMed1991

Desbuquois syndrome.

Three patients with short stature, joint laxity, and peculiar pelvic radiology are described. The first case is similar to those described by Desbuquois et al., with deviation of digitis and supernumerary metacarpal bones. The other two children are less severely affected and are compared with others reported in literature. The authors suggest the homogeneity of the Desbuquois syndrome in spite of the variability of expression.

Bone and Bones↗
PubMed1991

Transcription of cRNA for in situ hybridization from polymerase chain reaction-amplified DNA.

The synthesis of cRNA probes for in situ hybridization is usually accomplished with transcription systems using cloning vectors that contain bacteriophage RNA polymerase promoters. In this report we describe an alternative technique for generating cRNA probes that obviates the need for cDNA cloning by using the polymerase chain reaction. The segment of DNA corresponding to the desired RNA sequence was amplified from genomic DNA by the polymerase chain reaction. The bacteriophage SP6 and T7 RNA polymerase promoters were incorporated into the amplified DNA by including the promoter sequences in the 5' termini of the oligonucleotides used to prime the polymerase chain reaction. The promoters permitted the subsequent transcription of sense and antisense cRNA from the amplified DNA. The antisense cRNA was radiolabeled to high specific activity for use as a probe in Northern and mRNA in situ hybridization analyses. This technique offers the advantages of speed and simplicity over conventional transcription systems, which require cDNA cloning. Bypassing the need for cloning in the synthesis of cRNA probes may facilitate the use of these probes in research and diagnostic applications of mRNA in situ hybridization.

Animals↗
PubMed1991

Co-deposition of basement membrane components during the induction of murine splenic AA amyloid.

Past studies have demonstrated that during murine AA amyloid induction there is co-deposition of the AA amyloid peptide and the basement membrane form of heparan sulfate proteoglycan. The synthesis and accumulation of heparan sulfate proteoglycan does not usually occur in the absence of other basement membrane components, such as type IV collagen, laminin, and fibronectin. Using immunohistochemical techniques, the present experiments have demonstrated that in addition to the heparan sulfate proteoglycan, there are other basement membrane components present in splenic AA amyloid deposits and these are present as soon as AA amyloid deposits are detectable. The results indicate that within the time constraints imposed by the experiments, the basement membrane components, fibronectin, laminin, type IV collagen, and heparan sulfate proteoglycan are co-deposited 36 to 48 hours after the AgNO3 and amyloid enhancing factor induction of amyloid, the period when amyloid is first detected. These observations raise the possibility that an abnormality in basement membrane metabolism is a very early event, and potentially plays an integral part in the process of AA amyloidogenesis.

Animals↗