Immobilization of tyrosinase for use in nonaqueous media: Enzyme deactivation phenomena

Summary We have investigated features for minimizing the inactivation of tyrosinase (E.C. 1.14.18.1) that is caused by immobilization on glass beads and Celite^®. The degree of inactivation is dependent on the enzyme loading and the carrier's surface area. Addition of a sacrificial protein during the immobilization procedure offers a protective effect with increased residual activity on the basis of comparable enzyme loading.     

The H+/O ratio of proton translocation linked to the oxidation of succinate by mitochondria

In a recent communication Lehninger and co-workers (Costa, L.E., Reynaferje, B., and Lehninger, A.L. (1984) J. Biol. Chem. 259, 4802-4811) reported values approaching 8 for the H+/O ratio of vectorial proton ejection from rat liver mitochondria respiring with succinate. Here we present a rigorous analysis of these measurements which reveals that they may significantly overestimate the true H+/O stoicheiometry.     

Blood chemistry of the common marmoset (Callithrix jacchus) maintained in an indoor-outdoor environment: Primate comparisons

Blood chemistry values were collected over a three-year period from at least 10 colony-born and 24 wild-born apparently normal common marmosets. BUN, SGOT, creatinine, calcium, phosphorus, alkaline phosphatase, protein, albumin, cholesterol, triglycerides, uric and glucose values were determined. A statistical comparison of baseline values was made between wild-born, colony-born, male and female marmosets. Also the same comparison was made between common marmosets and cotton-top tamarins, white lipped tamarins and human subjects.     

ACTION DE L'ANHYDRIDE CARBONIQUE ET DE FACTEURS VISUELS SUR LES PERFORMANCES DE PIEGES «MANITOBA» MODIFIES EN MILIEU MONTAGNARD

Résumé Les performances de pièges à Tabanidae de type Manitoba ont été étudiées en milieu montagnard et subalpin. On a testé les influences respectives de la présence ou de l'absence d'une source de CO₂, de la nature de cette source (solide ou gazeuse), de la présence ou de l'absence d'un leurre visuel (sphère noir brillant), de la nature transparente ou opaque de la partie supérieure du piège (hotte conique). Plus de 8.000 Tabanidae et plus de 51.000 Muscidae ont été pris au cours de ces essais totalisant 660 heures-pièges.

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Summary Manitoba traps, traps without decoy or with black canopy, unbaited or baited with dry ice or compressed carbon dioxide, were compared for the numbers of horse flies and muscid flies caught in mountainous mixed wood and pasture land and in subalpine larch forest between 1500 m and 2200 m, in July. More muscid flies were captured in the compressed CO₂ baited traps than in dry ice baited traps. Haematopota pluvialis, Tabanus maculicornis and Tabanus quatuornotatus were more attracted by CO₂ than Tabanus bromius. T. bromius was more attracted by the decoy than other species. The genus Atylotus and T. bromius are more attracted to the black canopy than other species. The visual decoy is more necessary to the efficiency of the trap than the chemical bait. The CO₂ baited Manitoba trap caught the greatest number of horse flies (180 per trap and per hour). The unbaited Manitoba trap was efficient too, but other traps were inefficient. About 8000 horse flies and 51000 muscid flies were caught.

     

Incidence of caries and abscesses in archeological Eskimo skeletal samples from point hope and Kodiak Island,Alaska

The incidence of caries and abscesses in 246 archeologically derived skeletal specimens from the Ipiutak and Tigara levels at Point Hope, Alaska, and 79 specimens excavated from Jones Point, Kodiak Island, Alaska were investigated. All three collections span long periods of time. Only pre-white contact specimens were used. Each specimens was sexed and aged in five year groupings, using standard techniques. Caries and abscesses were recorded by type and degree of severity and correlated with age, sex, and site of origin. All samples displayed very low caries rates and few abscesses per tooth and per individual (both observed frequencies, and frequencies corrected for postmortem loss of teeth). DMF scores were tabulated using both observed and corrected frequencies. Very heavy occlusal wear in all three samples could account for the majority of abscesses and pulp exposures, while the low caries rates are attributable to traditional diets totally devoid of refined sugars, starches, and food additives.     

Hyperparathyroidism in pregnancy: case report and review of the literature.

The apparent incidence of hyperparathyroidism (HPT) is low in pregnancy but will likely increase now that more asymptomatic HPT is being diagnosed. However, since the serum calcium levels are decreased in pregnant women, mild primary HPT may go unrecognized. In untreated cases of HPT, complications during pregnancy or during the neonatal period have included spontaneous abortion, stillbirth, neonatal death, neonatal tetany and hypercalcemia. A review of the literature indicates a substantial improvement in fetal outcome when parathyroidectomy is done during pregnancy, as in the case reported here. Therefore, parathyroidectomy is the treatment of choice when the diagnosis is made during pregnancy, although oral phosphate therapy may be an alternative if surgery is contraindicated.     

Application of antimony microelectrodes to intracellular pH monitoring

Some novel studies of the properties of the antimony microelectrode used for intracellular pH measurements are described. First, it is shown that currents in the picoampere range, such as those encountered as leakage in some electrometers, induce important changes in pH sensitivity. The response time of the electrode has also been measured and indicates that the electrode exhibits a rapid time course which would be very useful for dynamic cytoplasmic pH investigations. An example of internal pH recording during cellular acidification in Xenopus laevis oocyte is also presented.