[Radiologic aspects of infarction of the appendix epiploica]

Clinical, US, CT and MR findings were reviewed in 5 patients with primary epiploic appendagitis (3 men, 2 women, mean age 38 years, age range 29-62 years) seen between December 1994 and December 1997. Diagnosis was reached in all cases with CT, with US in 3 and with MR in 1. Follow-up CT was performed in 2 cases and clinical follow-up in 4. One patient underwent surgery. Initial US, CT or MR examinations revealed a fatty oval-shaped nodule located anteriorly or anterolaterally to the left colon. The greater diameter ranged from 20 to 30 mm. Perinodular lesions with strands of periappendicular fat and thickened parietal peritoneum were visualized in all cases without any other inflammatory process in the abdomen. Symptoms resolved within 4 days in all patients. Signs of fatty inflammatory processes resolved in the 2 patients who had follow-up CTs. Primary epiploic appendagitis has characteristic US, CT and MR features which help guide medical treatment.

[Diagnostic imaging of idiopathic segmental infarct of the greater omentum. Diagnostic and physiopathologic considerations]

Primary infarction of the greater omentum is a rare cause of acute abdominal syndrome. Rate of occurrence may nevertheless be underestimated. We report a series of six cases observed over a 30-month period with US and CT imaging. We assessed early signs and their course. CT-scans depicted fatty oval-shaped masses below the right anterior or anterolateral parietal wall, associated with a thickening of the anterior parietal peritoneum, explaining symptom pathogenesis. Torsion can be identified, but has no specific impact on prognosis. Follow-up CT scan may evidence spontaneous, but sometimes slow, resolution.

Localization of two insulin-dependent diabetes (Idd) genes to the Idd10 region on mouse chromosome 3

Multiple genes control the development of autoimmune diabetes both in humans and in the nonobese diabetic (NOD) strain of mouse. Previously, three insulin-dependent diabetes (Idd) genes, Idd3, Idd10, and Idd17, were localized to mouse Chromosome (Chr) 3. The B10- or B6-derived resistance alleles at Idd10 and Idd3 together provide the NOD mouse with nearly complete protection from diabetes. In the present study, the 10.2-cM region encoding Idd10 was defined further with newly developed congenic strains. A locus, located in the centromeric 2.1 cM of the 10.2 cM region, contributed to the Idd10 trait. However, this locus did not account for the full effect of Idd10, suggesting the presence of a second gene in the distal portion of the 10.2-cM region. This second gene is designated as Idd18 and is localized to a 5.1-cM region. The resolution of the originally defined Idd3 locus into at least four separate loci, Idd3, Idd10, Idd17, and Idd18, illustrates the complex polygenic nature of diabetes.

[MRI aspect of hepatic adenomatosis]

We report a case of hepatic adenomatosis demonstrated with MR imaging. The diagnosis can be suspected when this technique shows multiple hepatic lesions which present an iso-signal intensity on T1-wi, a hyperintense signal on T2-wi and rapid wash-in and wash-out of gadolinium. Injection of superparamagnetic iron oxide mag be useful in the characterization of the lesion: a decreased signal intensity after injection rules out the diagnosis of metastasis. Because of the unknown course of hepatic adenomatosis, histological proof and radiological follow-up are recommended.

Congenic mapping of the insulin-dependent diabetes (Idd) gene, Idd10, localizes two genes mediating the Idd10 effect and eliminates the candidate Fcgr1

The development of autoimmune diabetes in the nonobese diabetic (NOD) mouse is under the control of multiple insulin-dependent diabetes (Idd) genes. The Idd3 gene, originally defined as a broad peak of linkage on mouse chromosome 3, was subsequently identified as two genes, Idd3 and Idd10, separated by at least 20 cM. The resistance alleles of Idd3 and Idd10 individually confer only partial protection from diabetes but, in combination, result in profound resistance to disease due to an epistatic genetic interaction. In this study, we used newly developed congenic strains to further localize Idd10. Surprisingly, we found that Idd10 itself comprises at least two linked loci: Idd10 and the newly designated Idd17. Idd17 was localized to a 1.1-cM region between D3Mit26 and D3Mit40, proximal to Fcgr1, a candidate gene encoding the high affinity Fc receptor for IgG. Idd10 was localized to a 10-cM region between D3Mit213 and D3Mit106, distal to Fcgr1. Thus, Fcgr1 was excluded as a candidate for either Idd10 or Idd17, despite the fact that the NOD strain expresses a mutant form of the receptor. Interestingly, although Idd10 and Idd17 participate in a genetic interaction with each other, Idd10 but not Idd17 participates in the genetic interaction with Idd3. Our study on chromosome 3 begins to reveal the extent of the polygenic nature of autoimmune diabetes, and demonstrates that the use of congenic strains is an effective mapping strategy, even in the dissection of multiple, linked genes with subtle effects.

Congenic mapping of the insulin-dependent diabetes (Idd) gene, Idd10, localizes two genes mediating the Idd10 effect and eliminates the candidate Fcgr1

The development of autoimmune diabetes in the nonobese diabetic (NOD) mouse is under the control of multiple insulin-dependent diabetes (Idd) genes. The Idd3 gene, originally defined as a broad peak of linkage on mouse chromosome 3, was subsequently identified as two genes, Idd3 and Idd10, separated by at least 20 cM. The resistance alleles of Idd3 and Idd10 individually confer only partial protection from diabetes but, in combination, result in profound resistance to disease due to an epistatic genetic interaction. In this study, we used newly developed congenic strains to further localize Idd10. Surprisingly, we found that Idd10 itself comprises at least two linked loci: Idd10 and the newly designated Idd17. Idd17 was localized to a 1.1-cM region between D3Mit26 and D3Mit40, proximal to Fcgr1, a candidate gene encoding the high affinity Fc receptor for IgG. Idd10 was localized to a 10-cM region between D3Mit213 and D3Mit106, distal to Fcgr1. Thus, Fcgr1 was excluded as a candidate for either Idd10 or Idd17, despite the fact that the NOD strain expresses a mutant form of the receptor. Interestingly, although Idd10 and Idd17 participate in a genetic interaction with each other, Idd10 but not Idd17 participates in the genetic interaction with Idd3. Our study on chromosome 3 begins to reveal the extent of the polygenic nature of autoimmune diabetes, and demonstrates that the use of congenic strains is an effective mapping strategy, even in the dissection of multiple, linked genes with subtle effects.

HOSEpipe--a WWW-hosted data management and analysis system for STS content mapping projects

We have developed a data management system, 'HOSEpipe' (High Output STS Evaluation pipeline) to aid sample tracking and data analysis in STS content mapping projects. The system is based around a World Wide Web (WWW) server that provides a number of pages including forms for sample processing and data entry accessible via a standard WWW browser application. The system is split into two main modules: firstly, a sequence evaluation and annotation module that takes de novo sequence for a potential STS, screens it against existing STSs and DNA sequence databases, followed by appropriate primer sequence design; secondly, a module that handles YAC library STS screening and includes facilities for both sample tracking and experimental data analysis. We present the design and rationale of the HOSEpipe system and its development to support a whole chromosomal physical mapping project. This software and design approach is potentially applicable to physical mapping projects of varying sizes and resolution and to similar projects, such as sample sequencing and the construction of sequence-ready maps.

Thiostrepton binds to malarial plastid rRNA

Binding of the thiazolyl peptide antibiotic thiostrepton to the GTPase domain of 23S rRNA involves a few crucial nucleotides, notably A1067 (E. coli). Small RNA transcripts were prepared corresponding to the GTPase domain of the plastid 23S rRNA and the two forms of cytosolic 28S rRNAs found in the human malaria parasite Plasmodium falciparum, as well as the plastid form of rRNA of the AIDS-related pathogen Toxoplasma gondii. Binding affinities of the wild type and mutated RNA sequences were as predicted; the malarial plastid sequence had by far the highest affinity, whereas that from toxoplasma did not bind thiostrepton.

Mapping of the IDDM locus Idd3 to a 0.35-cM interval containing the interleukin-2 gene

Currently, 16 loci that contribute to the development of IDDM in the NOD mouse have been mapped by linkage analysis. To fine map these loci, we used congenic mapping. Using this approach, we localized the Idd3 locus to a 0.35-cM interval on chromosome 3 containing the Il2 gene. Segregation analysis of the known variations within this interval indicated that only one variant, a serine-to-proline substitution at position 6 of the mature interleukin-2 (IL-2) protein, consistently segregates with IDDM in crosses between NOD and a series of nondiabetic mouse strains. These data, taken together with the immunomodulatory role of IL-2, provide circumstantial evidence in support of the hypothesis that Idd3 is an allelic variation of the Il2 gene, or a variant in strong linkage disequilibrium.

The Sry-related HMG box-containing gene Sox6 is expressed in the adult testis and developing nervous system of the mouse

We have cloned and sequenced a full-length cDNA for the HMG box-containing, SRY-related gene Sox6 from mouse. The deduced protein sequence of Sox6 has considerable homology with that of the previously determined Sox5 sequence. It seems likely that these genes have diverged more recently than other members of the SOX gene family, although the two genes map to different chromosomes in the mouse. In common with Sox5, Sox6 is highly expressed in the adult mouse testis and the HMG domains of both proteins bind to the sequence 5'-AACAAT-3'. This suggests that the two genes may have overlapping functions in the regulation of gene expression during spermatogenesis in the adult mouse. However, Sox6 may have an additional role in the mouse embryo, where it is specifically expressed in the developing nervous system.

DNA binding and bending properties of the post-meiotically expressed Sry-related protein Sox-5

Sox-5 is one of a family of genes which show homology to the HMG box region of the testis determining gene SRY. We have used indirect immunofluorescence to show that Sox-5 protein is localized to the nucleus of post-meiotic round spermatids in the mouse testis. In vitro footprinting and gel retardation assays demonstrate that Sox-5 binds specifically to the sequence AACAAT with moderately high affinity (Kd of approximately 10(-9) M). Moreover, interaction of Sox-5 with its target DNA induces a significant bend in the DNA, characteristic of HMG box proteins. Circular dichroism spectroscopy of the Sox-5 HMG box and its specific complex with DNA shows an alteration in the DNA spectrum, perhaps as a consequence of DNA bending, but none in the protein spectrum on complex formation. The dependence of the change in the CD spectrum with protein to DNA ratio demonstrates the formation of a 1:1 complex. Analysis of the structure of the Sox-5 HMG box by 2D NMR suggests that both the location of helical secondary structure as well as the tertiary structure is similar to that of HMG1 box 2.

An SRY-related gene expressed during spermatogenesis in the mouse encodes a sequence-specific DNA-binding protein

SRY, the testis determining gene, encodes a member of a family of DNA binding proteins characterized by an amino acid sequence motif known as the HMG box. Using degenerate primers and the polymerase chain reaction, we have isolated SRY-related cDNAs from adult murine testis RNA. One of these, Sox-5, encodes a 43 kDa HMG-box protein with similarities to transcription activating proteins. Anti-Sox-5 antibody was used to analyse expression of Sox-5 in pre-pubertal testis and in fractionated spermatogenic cells. Sox-5 is restricted to post-meiotic germ cells, being found at highest levels in round spermatids. Sox-5 is a DNA binding protein and binding site selection assays suggest that it can bind specifically to oligonucleotides containing the consensus motif AACAAT. Sry can also bind to this motif, indicating that the Sry family may have overlapping sequence specificities.

A zinc finger protein-encoding gene expressed in the post-meiotic phase of spermatogenesis

Spermatogenesis is the complex series of physiological and morphological changes that occur when spermatogonial stem cells differentiate into mature spermatozoa. Some of these changes are likely to be regulated at the level of transcription. To approach this problem, we have cloned a cDNA from mouse testis, encoding a protein (Zfp-29) with 14 copies of the zinc finger (Zf) motif commonly found in transcriptional regulatory proteins. The expression of this gene, Zfp-29, is restricted to the testis in adult mice, but also occurs during embryonic development. Within the testis, Zfp-29 mRNA is enriched in round spermatids, the earliest post-meiotic cells. Thus, the putative Zfp-29-encoded protein may have a role in regulating the class of genes that are expressed in post-meiotic germ cells.

Expression of tachykinins by ileal and lung carcinoid tumors assessed by combined in situ hybridization, immunocytochemistry, and radioimmunoassay

Mid-gut carcinoid tumors have been shown to produce substance P, a tachykinin. A recent addition to this family of peptides is neurokinin A which is cleaved from the same precursor as substance P; beta-pre-pro-tachykinin. The authors have examined mid-gut and pulmonary carcinoid tumors for the presence of the two tachykinins, using immunocytochemical study and radioimmunoassay, and have applied the techniques of in situ hybridization and Northern blot analysis to investigate the expression of mRNA for beta-pre-pro-tachykinin. All gut tumors (n = 8) and three of the six lung tumors examined were found by immunocytochemical study to contain both tachykinins or neurokinin A alone. Chromatographic analysis of tumor extracts suggests that this peptide is being detected as a separate molecule and/or as the C-terminal portion of a larger, uncleaved form. Three of the cases positive for tachykinins showed no detectable serotonin immunoreactivity. Strong hybridization signals for beta-pre-pro-tachykinin mRNA were seen in all but one of the cases studied which contained tachykinin immunoreactivity. Intact mRNA and positive hybridization was found by Northern blot analysis in two mid-gut tumors. Concentrations of tachykinins were found by radioimmunoassay to be higher in mid-gut tumors (substance P 27.2 +/- 19.7 pmol/g; neurokinin A 31.8 +/- 24.2 pmol/g; mean +/- SEM, n = 5) than in lung cases (substance P mean 0.8, range 0.5-1.0 pmol/g; neurokinin A mean 11.0, range 10.0-12.0 pmol/g; n = 3). These results show that mid-gut and pulmonary carcinoid tumors produce tachykinins, which are detected, in some cases, where no serotonin immunoreactivity can be found, possibly because of a high rate of amine secretion. Screening for tachykinins may prove to be a useful diagnostic adjunct for these tumors.

Detection of human probombesin mRNA in neuroendocrine (small cell) carcinoma of the lung. In situ hybridization with cRNA probe

The production of human bombesin (gastrin-releasing peptide), a peptide with mitogenic action, is a recognized feature of neuroendocrine (small cell) carcinoma of the lung. However, immunostaining of bombesin is not always possible in these tumors, probably because of poor storage mechanisms or rapid release of hormone. Molecular biological analysis of the gene encoding human bombesin has revealed the DNA sequence of human pro-bombesin. We have used in situ hybridization to study the expression of the human bombesin gene at the cellular level in small cell carcinoma of the lung. Probombesin cDNA was subcloned in pSP64 vector, linearized with Bam HI and transcribed in the presence of phosphorus 32(32P)-cytosine triphosphate (CTP) and SP6 polymerase. The cRNA probe was applied to tissue sections (from six cases of small cell carcinoma of the lung, freshly fixed in 4% paraformaldehyde), cell culture preparations (two different cell lines of small cell carcinoma), and cytologic specimens (smears of cells from three different cases of small cell carcinoma). Hybridization of probombesin mRNA was detected in tumor cells in all samples. Specificity of the signal was determined by control experiments, including the use of a probe which has a sequence identical to probombesin mRNA. Our results provide evidence for the expression of the bombesin gene in small cell carcinoma of the lung at a cellular level and show that probombesin mRNA is highly expressed in these tumors.

Generation of DNA probes for peptides with highly degenerate codons using mixed primer PCR

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Calcitonin gene-related peptide messenger RNA is expressed in sensory neurones of the dorsal root ganglia and also in spinal motoneurones in man and rat

Calcitonin gene-related peptide (CGRP) mRNA was localised to neurones of the dorsal root ganglia and motoneurones of the ventral horn in man and rat. Presence of alpha- and beta-CGRP mRNA was confirmed by Northern blot analysis of rat tissues which showed alpha-CGRP was the predominant gene. The distribution of CGRP gene transcripts corresponded with neurones displaying CGRP immunoreactivity in the ganglia of both species and in the rat ventral horn. In man few motoneurones were immunoreactive despite many expressing CGRP mRNA. In situ hybridisation revealed not only sensory but also motor neurones are sites of CGRP manufacture. Thus in conjunction with other evidence the present study reinforces the proposed muscle trophic role for this peptide.