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M Mina

Publications and source records attributed to M Mina.

34 records · Page 2Linked to original sources
PubMed1988

Assay of ATP-sulfurylase activity from rat liver by high-performance liquid chromatography.

Alteration of proteoglycan composition is known to accompany morphogenesis. In many tissues one such alteration is the removal of hyaluronate and its replacement with a sulfated proteoglycan. Several mechanisms that could regulate this alteration have been studied leading to a hypothesis that the increase in the sulfated proteoglycan is regulated by controlling the activity of those enzymes involved in the activation of the sulfate. To measure any variations in these activities usually begins with a purification of the enzyme. However, this procedure is difficult to perform where tissue samples are difficult to obtain in large enough quantities. Therefore, the examination of an enzymatic activity when tissue samples are in short supply requires the development of methods for the assay of the specific activity after a minimum of purification. In this paper we report on the development of just such an assay for ATP-sulfurylase, the enzyme that catalyses the first step in the activation of sulfate. This method uses anion-exchange high-performance liquid chromatography and differs from a previously published procedure [F. A. Hommes and L. Moss, Anal. Biochem., 154 (1986) 100] in that the compounds are detected spectrophotometrically instead of radiometrically and also in that the ATP, ADP, AMP and their sulfated analogues, adenosine 5'-phosphosulfate and 3'-phosphoadenosine 5'-phosphosulfate, are separated isocratically. Studies performed with 35SO4(2-) were used to validate this new method. The separation of all these compounds has allowed us to develop a one-step, on-line assay procedure which can be performed on small samples of partially purified preparations. We have used this procedure to measure the activity of the ATP sulfurylase in extracts of rat liver and tongue. Our results indicated that the ATP-sulfurylase activity from rat liver was soluble with a pH optimum of 8.0. The identity of the reaction product was verified using radiolabeled sulfate as the substrate and recovering the radiolabel in the product. Preliminary kinetic studies with this method showed the sulfurylase activity to have an apparent Michaelis constant of 3 microM and a maximal velocity of 0.56 pmol/min per mg protein.

Adenine Nucleotides↗
PubMed1987

The induction of odontogenesis in non-dental mesenchyme combined with early murine mandibular arch epithelium.

First and second branchial arches were dissected from mouse embryos of 9-13 days gestational age. The epithelial and mesenchymal components were separated after enzymic digestion. Scanning electron microscopy did not reveal a dental lamina along the dental arches before day 12, after which the lamina was formed locally in the incisor and molar regions. There was no epithelial down-growth in the diastema region. Heterotypic recombinations of mandibular arch and second branchial arch tissues showed that early mandibular arch epithelia, before day 12, have odontogenic potential and can elicit the formation of a dental papilla in non-odontogenic, neural-crest-derived mesenchymal cells of the second arch. However, the mandibular mesenchyme must interact with mandibular epithelium in order to have the competence to induce teeth in non-odontogenic epithelium.

Animals↗
PubMed1985

Sarcoidosis of the larynx in a child.

Sarcoidosis is a multisystem disease of unknown etiology characterized by non-caseating granulomatous inflammation of various organs, but most frequently involving the lungs of young adults. Sarcoidosis is rare in the pediatric age group, however numerous extensive reviews have been published. The most commonly seen initial manifestations in childhood are non-specific constitutional symptoms such as lethargy, fatigue and malaise, followed by cough, dyspnea, fever, weight loss, and lymphadenopathy in order of decreasing frequency. The diagnosis is one of exclusion and is established when clinical and radiological findings are supported by histological evidence of widespread non-caseating epithelial cell granulomas in more than one organ, or a positive Kveim test. Laryngeal involvement is usually part of the systemic disease, but isolated laryngeal sarcoidosis has been reported in adults. We report here a case of isolated laryngeal sarcoidosis in a 13 year old girl. The differential diagnosis and management are discussed.

Adolescent↗
PubMedDate not supplied

Using magnostrictive metal as a pump for biomedical application.

A new theory of pumping fluids, including blood, has been developed using magnetostrictive technology. This new pump uses the magnetostrictive material known as Terfenol-DTM. A magnetic field is imposed on the Terfenol in periodic pulses causing it to expand and then relax to its original state. The expansion and relaxation of the terfenol cause a smooth, continuous flow of fluid. This pump is currently being built and will be tested as a left ventricular assist device, totally implantable artificial heart, or both.

Electric Power Supplies↗
PubMedDate not supplied

Role of the early epithelium in the patterning of the teeth and Meckel's cartilage.

Embryonic epithelium from the mandibular branchial arch organizes the dentition and the deposition of Meckel's cartilage. During 9-11 days of gestation mandibular arch epithelium can induce teeth in nondental ectomesenchyme in both mice and birds. In addition, the deposition of Meckel's cartilage as a rod of cartilage in the middle of the first branchial arch is under the control of the epithelium. The epithelium inhibits chondrogenesis; if it is removed, large amorphous masses of cartilage are found instead of the narrow rod typical of Meckel's cartilage.

Animals↗