Identification and biochemical characterization of p70TRK, product of the human TRK oncogene.

TRK is a human transforming gene generated in a colon carcinoma by a somatic rearrangement that fused a nonmuscle tropomyosin gene to sequences that shared extensive homology with members of the tyrosine-protein kinase supergene family. These sequences are likely to be derived from a transmembrane receptor gene whose putative ligand binding domain has been replaced by tropomyosin. In the present studies, we have expressed the entire coding sequences of the TRK oncogene as well as its protein kinase-related carboxyl-terminal domain in Escherichia coli. Antisera raised against these bacteria-synthesized TRK polypeptides has allowed us to identify the gene product of the TRK oncogene as a 70-kDa protein. Immunoprecipitates containing p70TRK have an associated protein kinase activity specific for tyrosine residues. Moreover, p70TRK is phosphorylated in vivo in serine (75%), threonine (20%), and tyrosine (5%) residues. Finally, immunofluorescence and cellular fractionation studies indicate that p70TRK is preferentially located in the cytoplasmic fraction.     

Genetic Characterization of Echinococcus granulosus from a Large Number of Formalin-Fixed,Paraffin-Embedded Tissue Samples of Human Isolates in Iran

Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, presents an important medical and veterinary problem globally, including that in Iran. Different genotypes of E. granulosus have been reported from human isolates worldwide. This study identifies the genotype of the parasite responsible for human hydatidosis in three provinces of Iran using formalin-fixed paraffin-embedded tissue samples. In this study, 200 formalin-fixed paraffin-embedded tissue samples from human CE cases were collected from Alborz, Tehran, and Kerman provinces. Polymerase chain reaction amplification and sequencing of the partial mitochondrial cytochrome c oxidase subunit 1 gene were performed for genetic characterization of the samples. Phylogenetic analysis of the isolates from this study and reference sequences of different genotypes was done using a maximum likelihood method. In total, 54.4%, 0.8%, 1%, and 40.8% of the samples were identified as the G1, G2, G3, and G6 genotypes, respectively. The findings of the current study confirm the G1 genotype (sheep strain) to be the most prevalent genotype involved in human CE cases in Iran and indicates the high prevalence of the G6 genotype with a high infectivity for humans. Furthermore, this study illustrates the first documented human CE case in Iran infected with the G2 genotype.     

Corneal Confocal Microscopy Identifies Small-Fiber Neuropathy in Subjects With Impaired Glucose Tolerance Who Develop Type 2 Diabetes

OBJECTIVEImpaired glucose tolerance (IGT) through to type 2 diabetes is thought to confer a continuum of risk for neuropathy. Identification of subjects at high risk of developing type 2 diabetes and, hence, worsening neuropathy would allow identification and risk stratification for more aggressive management.RESULTSTen subjects who developed type 2 diabetes had a significantly lower CNFD (P = 0.003), CNBD (P = 0.04), and CNFL (P = 0.04) compared with control subjects at baseline and a further reduction in CNFL (P = 0.006), intraepidermal nerve fiber density (IENFD) (P = 0.02), and mean dendritic length (MDL) (P = 0.02) over 3 years. Fifteen subjects who remained IGT and 5 subjects who returned to normal glucose tolerance had no significant baseline abnormality on CCM or IENFD but had a lower MDL (P < 0.0001) compared with control subjects. The IGT subjects showed a significant decrease in IENFD (P = 0.02) but no change in MDL or CCM over 3 years. Those who returned to NGT showed an increase in CNFD (P = 0.05), CNBD (P = 0.04), and CNFL (P = 0.05), but a decrease in IENFD (P = 0.02), over 3 years.CONCLUSIONSCCM and skin biopsy detect a small-fiber neuropathy in subjects with IGT who develop type 2 diabetes and also show a dynamic worsening or improvement in corneal and intraepidermal nerve morphology in relation to change in glucose tolerance status.     

Small Nerve Fiber Quantification in the Diagnosis of Diabetic Sensorimotor Polyneuropathy: Comparing Corneal Confocal Microscopy With Intraepidermal Nerve Fiber Density

OBJECTIVE

Quantitative assessment of small fiber damage is key to the early diagnosis and assessment of progression or regression of diabetic sensorimotor polyneuropathy (DSPN). Intraepidermal nerve fiber density (IENFD) is the current gold standard, but corneal confocal microscopy (CCM), an in vivo ophthalmic imaging modality, has the potential to be a noninvasive and objective image biomarker for identifying small fiber damage. The purpose of this study was to determine the diagnostic performance of CCM and IENFD by using the current guidelines as the reference standard.

RESEARCH DESIGN AND METHODS

Eighty-nine subjects (26 control subjects and 63 patients with type 1 diabetes), with and without DSPN, underwent a detailed assessment of neuropathy, including CCM and skin biopsy.

RESULTS

Manual and automated corneal nerve fiber density (CNFD) (P < 0.0001), branch density (CNBD) (P < 0.0001) and length (CNFL) (P < 0.0001), and IENFD (P < 0.001) were significantly reduced in patients with diabetes with DSPN compared with control subjects. The area under the receiver operating characteristic curve for identifying DSPN was 0.82 for manual CNFD, 0.80 for automated CNFD, and 0.66 for IENFD, which did not differ significantly (P = 0.14).

CONCLUSIONS

This study shows comparable diagnostic efficiency between CCM and IENFD, providing further support for the clinical utility of CCM as a surrogate end point for DSPN.     

The CD47-signal regulatory protein alpha (SIRPa) interaction is a therapeutic target for human solid tumors

CD47, a "don't eat me" signal for phagocytic cells, is expressed on the surface of all human solid tumor cells. Analysis of patient tumor and matched adjacent normal (nontumor) tissue revealed that CD47 is overexpressed on cancer cells. CD47 mRNA expression levels correlated with a decreased probability of survival for multiple types of cancer. CD47 is a ligand for SIRPα, a protein expressed on macrophages and dendritic cells. In vitro, blockade of CD47 signaling using targeted monoclonal antibodies enabled macrophage phagocytosis of tumor cells that were otherwise protected. Administration of anti-CD47 antibodies inhibited tumor growth in orthotopic immunodeficient mouse xenotransplantation models established with patient tumor cells and increased the survival of the mice over time. Anti-CD47 antibody therapy initiated on larger tumors inhibited tumor growth and prevented or treated metastasis, but initiation of the therapy on smaller tumors was potentially curative. The safety and efficacy of targeting CD47 was further tested and validated in immune competent hosts using an orthotopic mouse breast cancer model. These results suggest all human solid tumor cells require CD47 expression to suppress phagocytic innate immune surveillance and elimination. These data, taken together with similar findings with other human neoplasms, show that CD47 is a commonly expressed molecule on all cancers, its function to block phagocytosis is known, and blockade of its function leads to tumor cell phagocytosis and elimination. CD47 is therefore a validated target for cancer therapies.