Reconstitution of interactions between the Src tyrosine kinases and Ras GTPase-activating protein using a baculovirus expression system

Ras GTPase-activating protein (GAP) has been implicated in mitogenic signal transduction downstream of oncogenic and receptor tyrosine kinases. Previous studies have suggested that GAP is phosphorylated by oncogenic viral Src (v-Src) and that GAP is associated with a complex containing normal cellular Src (c-Src) in vertebrate fibroblasts. To investigate molecular interactions between the Src kinases and GAP, we developed an in vitro system for reconstituting Src-GAP complexes. For this purpose, we constructed recombinant baculovirus vectors that direct expression of Rous sarcoma virus v-Src, chicken c-Src, and bovine GAP in infected Sf9 insect cells. In vitro reconstitution experiments using baculovirus-expressed proteins demonstrate that both v-Src and c-Src associate in complexes with GAP. In addition, in vitro and in vivo phosphorylation analyses indicate that GAP serves as a substrate for both the v-Src and c-Src tyrosine kinases. To determine which structural features of GAP are involved in interactions with the Src kinases, we constructed recombinant baculoviruses that encode deletion mutants of bovine GAP. Deletion of the GAP amino-terminal portion containing Src homology 2 regions, which are highly conserved structural motifs postulated to mediate interactions among proteins, diminishes GAP phosphorylation and association with Src. This reconstitution system should facilitate further studies of molecular interactions between the Src kinases and GAP.

A monoclonal antibody to common acute lymphoblastic leukemia antigen (CALLA) and its expression on several human tumor cell lines

We describe a newly-made murine monoclonal antibody to the common acute lymphoblastic leukemia antigen (CALLA), named SHB-10. The antigen detected by SHB-10 has a molecular weight of about 105 kDa. This antibody is very similar to that of conventional anti-CD10 Ab on indirect flowcytometric analysis using lymphoid malignant cell lines and peripheral lymphocytes of acute lymphoblastic leukemia (ALL) patients. The binding of anti-CD10 to Daudi cell and peripheral lymphocytes of ALL patients is blocked by SHB-10. Thus this monoclonal antibody is thought to detect the CALLA. The distribution of antigen detected by SHB-10 on several cell lines of neuroectodermal tumor and lymphoid malignancy was analysed and a slight difference in their cell surface expression is observed when compared with that by conventional anti-CD10. Further biochemical analysis is now under way for a better characterization of this antigen.

Impact of clinical history on film interpretation

We performed a study to determine whether clinical history gives a positive or negative influence on X-ray film interpretation. One hundred and nine patient's radiograms, consisting of 55 normal and 54 abnormal cases (136 abnormalities), were interpreted twice by three pairs of residents in radiology and a pair of qualified radiologists, without clinical history first and with clinical history next. The interpreters recorded diagnosis and confidence level of normal or abnormal findings on a six-point scale. Analysis of receiver operating characteristic (ROC) curves showed that knowledge of clinical history improved diagnostic accuracy. Residents, especially beginners, should be advised to obtain clinical history whenever they read radiograms.

Chromogranin-a expression in gastric and colon cancer tissues

We studied the expression of chromogranin A (CgA) in human gastric (n = 17) and colorectal (n = 18) adenocarcinomas by nucleic acid hybridization and immunohistochemical analyses using a specific monoclonal antibody (MAb) to human chromogranin A (CgA). Some corresponding adjacent non-malignant mucosal tissues were also examined.

RESULTS

(1) Northern blotting: of 3 normal gastric mucosas examined, 2 (67%) had an easily detected signal for expression of CgA. Only one of 14 gastric carcinomas (7%) and one of 18 colorectal carcinomas (6%) had easily detected RNA signals. (2) Immunohistochemical staining: all non-malignant samples of gastric and colonic mucosa contained CgA-positive neuroendocrine (NE) cells. Two of 17 (12%) gastric adenocarcinomas, and 3 of 18 (17%) of colorectal adenocarcinomas contained CgA-positive tumor cells. Interestingly, the positive cases detected by immunohistochemistry included both cases detected by Northern blotting. Of the 5 cases detected by immunohistochemistry, 2 gastric cancers and 1 rectal carcinoma contained many diffusely scattered positive cells, occurring singly or in small clusters, while 2 colorectal carcinomas contained only occasional single CgA-positive tumor cells. In one of the positive gastric cases, a well-differentiated adenocarcinoma arising in a tubular adenoma, both the adenomatous and the carcinomatous elements contained positively staining cells. Our specific assays for CgA indicate that (1) a NE cell component, either diffusely scattered or occasional, occurs in about 15% of gastric and colorectal tumors; (2) there is no correlation between the presence of NE cells and degree of tumor differentiation; and (3) because only a minority of the tumor cells in positive cases stain for CgA, immunohistochemistry is a more sensitive method than Northern blotting.

Intraventricular neurocytoma: clinicopathological analysis of seven cases

A retrospective analysis of seven patients with intraventricular neurocytoma is presented. Patient age at diagnosis ranged from 15 to 38 years (mean 24.6 years) and the male:female ratio was 6:1. Raised intracranial pressure due to hydrocephalus was the main cause of the clinical manifestations. An isodense mass with multiple intratumoral cysts and homogeneous contrast enhancement was the characteristic computerized tomography finding. The lesions commonly involved the lateral ventricle with or without extension to the third ventricle. Cerebral angiography showed homogeneous vascular staining in five patients. Magnetic resonance images revealed a mass isointense with the cerebral cortex on both T1- and T2-weighted images. Gadolinium-diethylenetriaminepenta-acetic acid-enhanced images showed homogeneous enhancement. Total removal of the tumor was possible in four patients. Pathologically, six cases were initially diagnosed as oligodendroglioma and the remaining case as ependymoma. However, immunohistochemical studies demonstrated strong positivity for neuron-specific enolase in all seven cases and for synaptophysin in five cases. On electron microscopy, three cases showed well-defined neurosecretory granules and 10-nm microtubules in their cytoplasm and cytoplasmic processes. One patient developed a recurrent tumor 18 months after surgery. The remaining six patients are free of recurrent tumors at 2 to 62 months after surgery. It is suggested that neurocytoma must be included in the differential diagnosis of intraventricular lesions, and that electron microscopic and immunohistochemical studies should be undertaken.

Malignant triton tumor of the acoustic nerve. Case report

The authors present the clinical, radiological, pathological features, and autopsy findings of a patient with malignant triton tumor of the acoustic nerve, which probably arose from a pre-existing acoustic schwannoma. The term "malignant triton tumor" is applied to malignant schwannomas with rhabdomyoblastic differentiation. A cerebellopontine angle tumor with spinal drop metastasis occurred in this patient 10 months after near-total removal of the original tumor.

HLA-DR expression in human fetal thymocytes

We analyzed the expression of MHC class I (W6/32) and class II (HLA-DR) antigens on human fetal and postnatal thymocytes by fluorescence-activated cell sorting. Less than 5% of prenatal thymocytes expressed HLA-DR before week 12 of gestation. However, the number of HLA-DR-positive cells significantly increased during the late second and third trimester of gestation, when greater than 50% of prenatal thymocytes expressed HLA-DR. Such high-level expressions of HLA-DR in fetal thymocytes were also demonstrated by Northern-blot analysis and immunohistochemistry. After birth, the percentage of HLA-DR-positive cells in thymocytes decreased gradually. A high-level expression of class I antigen was also observed in thymocytes from the early stages of gestation, but, in contrast to MHC class II, a majority of postnatal thymocytes maintained high levels of class I antigen after birth.

Thrombotic thrombocytopenic purpura-like syndrome associated with systemic lupus erythematosus--combined treatment with plasmapheresis and fresh frozen plasma infusion

We report on a patient with systemic lupus erythematosus, who, during the course of the illness, developed thrombotic thrombocytopenic purpura. In this case, the coexistence of these two conditions was confirmed by laboratory and pathologic findings. The infusion of fresh frozen plasma with plasmapheresis reversed the course of thrombotic thrombocytopenic purpura.

Osmotic and growth-phase dependent regulation of the eta gene of Staphylococcus aureus: a role for DNA supercoiling

Transcriptional fusions were constructed between the promoter for the epidermolytic toxin A (eta) gene of Staphylococcus aureus and the luxAB and xylE reporter gene systems. The expression of the fusion products was found to be dependent upon the accessory gene regulator (agr) locus and was observed to increase significantly during the transition from the exponential to the stationary phase of growth. Furthermore the expression of the eta gene promoter was found to be osmotically regulated, with the expression levels of the eta fusions being inversely related to the osmolyte levels. The ability of environmental factors to influence DNA topology (and thence gene expression) was investigated. High osmolarity (0.7 M NaCl) resulted in an increase in the degree of negative supercoiling of plasmid DNA in the S. aureus strain 8325-4 (Agr+) but not in strain ISP546 (Agr-). Furthermore the eta promoter was strongly induced in S. aureus cultures grown in the presence of sub-inhibitory concentrations of novobiocin, a DNA gyrase inhibitor. However this induction was independent of agr, suggesting that the eta promoter is subject to both agr-dependent (osmolarity, growth phase) and-independent (DNA topology) regulatory processes.

Pneumocystis carinii infection in the middle ear

Pneumocystis carinii is the opportunistic pathogen frequently causing pneumonitis in the acquired immunodeficiency syndrome. Extrapulmonic manifestation of P carinii is unusual and is commonly associated with severe systemic illness, other immune deficiency status, malignancy, or immune suppression. We describe a case of acquired immunodeficiency syndrome with manifestations of P carinii otitis media with severe otalgia and conductive hearing loss.

A novel mitogen-inducible gene product related to p50/p105-NF-kappa B participates in transactivation through a kappa B site

A Rel-related, mitogen-inducible, kappa B-binding protein has been cloned as an immediate-early activation gene of human peripheral blood T cells. The cDNA has an open reading frame of 900 amino acids capable of encoding a 97-kDa protein. This protein is most similar to the 105-kDa precursor polypeptide of p50-NF-kappa B. Like the 105-kDa precursor, it contains an amino-terminal Rel-related domain of about 300 amino acids and a carboxy-terminal domain containing six full cell cycle or ankyrin repeats. In vitro-translated proteins, truncated downstream of the Rel domain and excluding the repeats, bind kappa B sites. We refer to the kappa B-binding, truncated protein as p50B by analogy with p50-NF-kappa B and to the full-length protein as p97. p50B is able to form heteromeric kappa B-binding complexes with RelB, as well as with p65 and p50, the two subunits of NF-kappa B. Transient-transfection experiments in embryonal carcinoma cells demonstrate a functional cooperation between p50B and RelB or p65 in transactivation of a reporter plasmid dependent on a kappa B site. The data imply the existence of a complex family of NF-kappa B-like transcription factors.

Transforming growth factor beta 1 as a biomarker for prostate cancer

Using the mouse prostate reconstitution (MPR) model system, under conditions where the ras and myc oncogenes are introduced via a recombinant retrovirus into both the mesenchymal and epithelial compartments of the urogenital sinus, poorly differentiated prostate cancer is produced with high frequency (> 90%) using inbred C57BL/6 mice. Northern blotting and immunohistochemical analysis showed that the transition from benign prostatic hyperplasia (BPH) to prostate cancer is invariably associated with the induction of elevated transforming growth factor-beta 1 (TGF-beta 1) expression. Similar analysis of TGF-beta 1 in human BPH and prostate cancer is consistent with our MPR results and indicates that the accumulation of extracellular TGF-beta 1 is significantly more intense in prostate cancer compared to normal or benign prostate tissues. Interestingly, where benign pathologies are observed in the prostatic stroma in the presence of benign prostatic epithelium, extracellular TGF-beta 1 is seen predominantly in the stromal compartment. Experimental studies clearly demonstrate that mRNA levels of TGF-beta 1 and other growth related genes are regulated by androgens in prostate cancer cells. Overall, our results suggest that elevated TGF-beta 1 is involved in the development of prostate cancer. Direct determination of TGF-beta 1 levels and distribution as well as analysis of localized and systemic effects produced by TGF-beta 1 may serve as useful biomarkers for prostate cancer.

Marchiafava-Bignami disease: serial changes in corpus callosum on MRI

Serial MRI findings of changes in corpus callosum lesions in two cases of Marchiafava-Bignami disease are presented. In both, MRI displayed diffuse swelling of the corpus callosum in the acute stage, thought to represent oedema and demyelination. In the chronic stage, in addition to atrophy of the corpus callosum with presumed focal necrosis, previously undescribed focal hypointensity on T2-weighted images, of unknown cause, was observed in the corpus callosum.

Congenital arteriovenous malformation associated with progressive hydrocephalus in a newborn

Intracranial arteriovenous malformation is rarely presented in newborns or infants. We describe an unusual case of congenital arteriovenous malformation of the brain with multiple sequestered grape-like venous sacs presented with congenital hydrocephalus. This 4-month-old girl born with a large head, presented with progressive hydrocephalus over a period of 4 months. The brain CT showed multiloculated cysts with a high-density mural nodule and thin cerebral mantle. The right lateral ventricle was collapsed by the cystic lesion, and the contralateral ventricle was markedly dilated, which was thought to be due to aqueductal obstruction by the conglomerated nidus of the arteriovenous malformation. Surgical removal of both hemispheric masses, including the overlying thin mantle. The lesion was pathologically confirmed as the arteriovenous malformation which was composed of markedly dilated veins and multiple sequestered aneurysmal sacs. The overlying cerebral tissue was dysplastic and partly infarcted. This case shows that intracerebral arteriovenous malformation is indeed a congenital anomaly and suggests that intrauterine vascular compromise can result in focal or wide maldevelopment of the brain.

Histologic comparison of regeneration in human intrabony defects when osteogenin is combined with demineralized freeze-dried bone allograft and with purified bovine collagen

A bone-inductive protein, osteogenin, has been isolated from long bones of humans and offers promise as a grafting material. Studies, however, suggest that osteogenin must be combined with a bone-derived matrix in order to initiate bone differentiation. The purpose of this study was to determine if osteogenin combined with demineralized freeze dried bone allograft (DFDBA), a bone-derived matrix, and with a bovine tendon-derived matrix will enhanced regeneration of intrabony defects in humans. The tendon-derived matrix and DFDBA used alone served as controls. The ability of each material to form a new attachment apparatus was evaluated independently in submerged and nonsubmerged environments in 2 patient populations. Lymphocyte testing was performed to assess development of an immune reaction to osteogenin. The most apical level of calculus on the root served as the histologic reference point to measure regeneration. Biopsies were obtained at 6 months and regeneration was measured histomorphometrically by 2 blinded evaluators. Serial sections from 36 submerged defects in 8 patients and 50 nonsubmerged defects in 6 patients were submitted for statistical analysis. Mean results indicate that osteogenin combined with DFDBA significantly enhanced regeneration of a new attachment apparatus and component tissues in a submerged environment. DFDBA plus osteogenin and DFDBA alone formed significantly more new attachment apparatus and component tissues than either the tendon-derived matrix plus osteogenin or the tendon-derived matrix alone in both submerged and nonsubmerged environments. There were no significant differences between the tendon-derived matrix plus osteogenin and the tendon-derived matrix alone in either the submerged or nonsubmerged environment. Osteogenin does not impair normal lymphocyte blastogenesis at 6 months postsurgical challenge.

Peripheral upper lobe collapse simulating pleural effusion

Two cases of segmental collapse of the upper lobe simulating an apical pleural effusion in association with pneumothorax are reported. Our cases differ from previously reported ones in that the peripheral collapse occurred in association with a pneumothorax without pleural adhesions, it was segmental rather than lobar, and was observed in adults.

Prokinetic effect of AS-4370 on gastric emptying in healthy adults

The effect of AS-4370 on gastric emptying was investigated in healthy adults using 99mTc-DTPA. Single doses of AS-4370 2.5, 5 or 10 mg or placebo were administered to 12 subjects in a controlled, double-blind, cross-over study. Tests were performed twice weekly in each subject. Thirty min after administration of test drug or placebo, each subject swallowed a bun and orange juice containing 200 microCi nuclide. The radioactivity of the gastric content was measured for 40 min and the activity of the residue was expressed as a percentage of count at the initiation of measurements. The percentage radioactivity, AUC and gastric emptying time fitted by a power exponential curve, were analyzed. No significant difference was observed between the three dose levels of AS-4370 and placebo in half emptying time. However, decreases in the percentage of radioactivity with time were noted; 5 mg at 10 to 16 min and 10 mg at 8 to 24 min after the start of recording. Lower AUCs after 5 mg and 10 mg compared to placebo were also found. The half emptying time was also shorter after 5 mg and 10 mg than placebo. There was no difference in these parameters between 2.5 mg and placebo. The results indicate that AS-4370 5 and 10 mg but not 2.5 mg accelerates gastric emptying in healthy adults.

Congenital granular cell tumor with systemic involvement. Immunohistochemical and ultrastructural study

We present an autopsy case of a 29-week-old male fetus with a very unusual set of congenital granular cell tumors, including gingival epulis and granular cell lesions of the kidneys, lung, heart, esophagus, small and large intestine, thyroid, adrenals, spleen, urinary bladder, testis, pituitary, and leptomeninges. The granular cells were distributed mainly through the stroma of the organs, but they also involved the epithelial lining of the seminiferous and renal tubules. Ultrastructurally, the gingival, pulmonary, and renal tumors were basically the same in appearance as membrane-bound heterogeneous bodies. Immunohistochemical studies were negative for S100 protein, lysozyme, alpha 1-antitrypsin, cytokeratin, and vimentin in the gingival mass as well as in other systemic lesions. The immunohistochemical reaction pattern of the granular cells in our case was more like the cells of the congenital granular cell epulis rather than adult granular cell tumor because of its negative reaction to S100 protein. However, the involvement pattern was that of the adult form of granular cell tumor. Several developmentally different cells, such as renal tubular epithelial cells, seminiferous tubular cells, gingival stromal cells, and parenchymal cells of many organs, were involved in this granular cell process. The myofibroblastlike cells seen in the region of segmental dysplasia of the kidney showed the same cytoplasmic material as in typical granular cells. Based on these findings, it is suggested that a histogenesis of multiple cell origin of the granular cell tumor could be strongly supported.