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Biomedical subjects

R Martinez

Publications and source records attributed to R Martinez.

At least 271 records · Page 15Linked to original sources
PubMed1985

Bilateral subluxation of the base of the thumb secondary to an unusual abductor pollicis longus insertion: a case report.

Bilateral subluxation of the trapeziometacarpal joint was related to abnormal insertion of the abductor pollicis longus (APL) tendon and an atrophic extensor pollicis brevis tendon. The APL tendon had four slips, all of which inserted into the fascia of the abductor pollicis brevis muscle distal and palmar to the trapeziometacarpal joint. Active pinch of the thumb resulted in subluxation of the trapeziometacarpal joint. To prevent reciprocal distal deformity, the proximal thumb was held in dynamic balance by attaching two slips of the APL tendon to the radiodorsal base of the first metacarpal. One tendon slip supplemented the tendon of the extensor pollicis brevis muscle. The lax capsule of the trapeziometacarpal joint was reinforced with the remaining tendon slip. The patient retains excellent bilateral function without subjective weakness after surgery.

Adolescent↗
PubMed1985

Protein phosphorylation in a tetradecanoyl phorbol acetate-nonproliferative variant of 3T3 cells.

The 3T3-TNR9 cell line is a variant of Swiss 3T3 cells which does not respond mitogenically to tumor promoters, but does respond mitogenically to epidermal growth factor, fibroblast growth factor, and serum. To elucidate differences between tumor promoters and polypeptide mitogens in the pathway(s) of mitogenesis which might be responsible for the nonresponsiveness of the 3T3-TNR9 cells, we have examined in these cells the early protein phosphorylation events known to be associated with mitogenesis in the parental 3T3 cells. We find that the 3T3-TNR9 cells display levels of tetradecanoyl phorbol acetate binding and of a calcium- and phospholipid-dependent protein kinase activity which are at least the equal of those seen in the parental 3T3 cells, implicating some postreceptor event in the nonmitogenic phenotype. In addition, we find that phosphorylation of the epidermal growth factor receptor and of 80-kDa and 22-kDa proteins, as well as the tyrosine phosphorylation of a 42-kDa protein, all proceed normally in the nonmitogenic variant, even though these phosphorylations must depend on the activation of different kinases. Thus, all these early phosphorylation reactions are intact in the 3T3-TNR9 cells. Although these phosphorylations may be necessary, they clearly are insufficient to trigger mitogenesis.

Animals↗
PubMed1985

[Severe early-onset thrombopenia induced by non-fractionated heparin: therapeutic trial with low molecular weight heparin].

A case of severe thrombocytopenia (27 x 10(3)/mm3) of early onset during unfractionated heparin (Héparine sodique Rovi) treatment is reported in a 75 year-old man suffering from a deep vein thrombosis of the right calf. It was not associated with thromboembolic or haemorrhagic complications. A serum heparin-dependent aggregating factor was not detected. Substitution of low molecular weight heparin (Choay Laboratory, CY 222, PM 4 500, 25 000 U anti-Xa/ml) for unfractionated heparin resulted in a progressive normalisation of the platelet count and improvement of the venous thrombosis.

Aged↗
PubMed1984

Estrogen and progesterone receptors in intracranial tumors.

Cytoplasmic estrogen receptor (ER) and progesterone receptor (PR) proteins were measured by a dextran-coated charcoal absorption technique in 19 intracranial tumors (10 meningiomas, two acoustic neurinomas, two glioblastomas, one primary tumor of neuroectodermal origin, one hemangioblastoma, one metastasis of carcinoma, one chordoma, and one pituitary adenoma). Positive PR values (greater than or equal to 10 fmol/mg of protein) were found in nine meningiomas (90% of these tumors), in the chordoma, in one glioblastoma, and in the hemangioblastoma, whereas positive ER values were recorded only in the pituitary adenoma and in one glioblastoma. Evidence of PR in meningiomas might explain their predominance in women. A possible pharmacological therapy, based on these findings, is discussed.

Adult↗
PubMed1984

Transient idiopathic periosteal reaction associated with dysproteinemia.

Periosteal reaction with new bone formation in a child is a radiographic finding with an extensive differential diagnosis. The present case is that of a child who presented with a clinical syndrome of fever, bone pain in the forearm and leg, bony tenderness in these areas, radiographic evidence of a periosteal reaction in both tibiae and ulnae, and an abnormality of serum proteins. It was a self-limited disease process requiring no specific treatment, with eventual return to normal of both the radiographic and serum protein abnormalities. Its relationship to Caffey's disease remains to be defined.

Child↗
PubMed1984

Natural transovarial transmission of dengue 4 virus in Aedes aegypti in Trinidad.

The isolation of dengue 4 virus from adult Aedes aegypti, reared from eggs collected in nature, is reported for the first time. From the locality where the isolate was made, 25 pools consisting of 1,848 Ae. aegypti reared from eggs were processed. In this study, 10 different localities were sampled and a total of 10,957 Ae. aegypti adults, collected as eggs or larvae in nature, were processed for virus isolation. From a total of 158 mosquito pools tested, one recovery of dengue 4 virus was made. The isolation of dengue 4 virus from this field-collected material gives further evidence that transovarial transmission of dengue viruses occurs in nature.

Aedes↗
PubMed1983

[Sarcoidosis].

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Adult↗
PubMed1983

A tumor promoter stimulates phosphorylation on tyrosine.

The tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate is mitogenic for normal chicken embryo fibroblasts and also causes these cells to express transiently many properties of cells transformed by Rous sarcoma virus. Since some mitogenic hormones stimulate a tyrosine-specific protein kinase activity, and since the transforming protein of RSV is a tyrosine-specific protein kinase, we have examined whether TPA also stimulates protein phosphorylation on tyrosine. We report here that TPA treatment of normal cells resulted in a very rapid phosphorylation on tyrosine of a protein peak of Mr 40 to 43 kilodaltons. Thus, a similar biochemical activity (tyrosine phosphorylation) is associated with the action of polypeptide mitogenic hormones, Rous sarcoma virus and a tumor promoter. In addition, TPA treatment resulted in rapid changes in phosphorylation of proteins on serine and threonine.

Animals↗
PubMed1983

Chordoma.

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Adult↗
PubMed1983

Tyrosine phosphorylation of specific proteins after mitogen stimulation of chicken embryo fibroblasts.

We found that stimulation of density-inhibited chicken embryo fibroblasts with serum, epidermal growth factor (EGF), platelet-derived growth factor, (PDGF), or multiplication-stimulating activity (MSA) leads to an increase in tyrosine phosphorylation of proteins in the region of Mr 40,000 (40K) to 42K. The increase in tyrosine phosphorylation after serum or EGF stimulation was transient, reaching a maximum at about 5 min and then declining. By fine-resolution analysis of proteins separated on sodium dodecyl sulfate-polyacrylamide gels, we found that after EGF stimulation, the major increase in phosphotyrosine content was in a 42K Mr protein, with a smaller increase in a 40K Mr protein. The increased phosphorylation in the 40K to 42K Mr region accounted for almost all of the increase in phosphotyrosine observed in these cells. These phosphotyrosine-containing proteins were different from the major phosphotyrosine-containing protein of Rous sarcoma virus-transformed chicken embryo fibroblasts, which migrates at an approximate Mr of 36K. Increased tyrosine phosphorylation of proteins of similar Mr was found in 3T3 cells treated with EGF, but not in NR-6 cells, which lack detectable EGF receptors. It is possible that the 40K to 42K Mr phosphotyrosine-containing proteins are involved in the integration of the biological response to a number of different growth factors.

Animals↗
PubMed1983

Cultured cells transformed by Rous sarcoma virus: a genetically defined model and its phenotype.

The mechanism by which Rous sarcoma virus transforms cells is better understood at the molecular level than that of any other oncogenic agent. The gene (src) responsible for transformation has been identified and its nucleotide sequence has been determined. The transforming protein (pp60src) has been identified and an enzymatic activity assigned to it. The unusual enzymatic activity of pp60src (phosphorylation of proteins on tyrosine) has allowed us to identify a large number of putative targets of this protein. And genetic evidence indicates that the phosphorylation of various targets is responsible for generating the various manifestations of the transformed phenotype. What can this model system contribute to understanding of hereditary large bowel cancer? First of all, it provides an intellectual paradigm for analyzing the mechanism by which a single autosomal dominant gene can alter the metabolism and regulatory behavior of a cell. A cellular homolog of src or of some other onc gene could be responsible for hereditary colon cancer. Second, it provides a model for understanding why some "markers" of malignancy are not invariably associated with cancer: since the oncogenic protein can interact with a variety of primary targets giving rise to the various parameters of transformation, not every sort of biological effect need be necessary for malignancy. Third, it points out that the various syndromes which constitute hereditary colon cancer may well be due to a single gene: since mutations in the src gene are capable of generating a variety of distinct phenotypic alterations in infected cells, different from that generated by the wild-type virus, it certainly is conceivable that different alleles of a single transforming gene could give rise to the different types of hereditary colon cancer. Whether this is the explanation for the various forms of hereditary colon cancer, or whether they result from the activities of several different onc genes can only be determined by identification of the gene(s) at the molecular level. Finally, this model system has provided information which may prove useful in improving the specificity of cancer chemotherapy. Since production of plasminogen activator seems to correlate well with growth in soft agar and tumorigenicity, an anti-cancer prodrug which is activated specifically by cells producing plasminogen activator might be selectively toxic to malignant cells. We have in fact synthesized such drugs and shown them to be selectively toxic in vitro to malignant cells (Carl et al 1980). In vivo tests of these agents are in progress.

Avian Sarcoma Viruses↗