Effect of Calcination Conditions on Crystalline Structure and Pore Size Distribution for a Mesoporous Alumina

In this article, a mesoporous commercial alumina was calcined in the temperature range of 600°C–1200°C. The effect of several parameters such as calcination temperature, calcination time, heating rate, and calcination steps on phase transformation and crystal size was experimentally investigated. The characterization of the commercial mesoporous alumina and samples calcined at 1000°C, 1040°C, 1070°C, 1100°C, and 1200°C by single-step and multi-step calcination was performed using XRD and N₂ adsorption/desorption techniques. For the commercial mesoporous alumina, TG/DTA analysis was also performed. Experimental results showed that mostly pure α-Al₂O₃ was obtained at 1100°C.     

Metabolic studies of guinea pig basophilic leukocytes in short-term tissue culture. I. Measurement of histaminesynthesizing capacity by using an isotopic-thin layer chromatographic assay

Mature circulating guinea pig basophils, purified to comprise 25% or more of leukocytes, have been successfully maintained in short-term tissue culture for up to 72 hr. These cells were found to retain the ability to synthesize histamine, as assayed by a new isotopic-thin layer chromatographic assay which can reliably detect as little as 0.5 pg of 3H-histamine. Cell-associated, newly synthesized histamine was detectable as early as 1 hr of culture, was substantially increased at 6 hr, and reached maximal levels at 24 hr, when it accounted for approximately 6.5% of total cell histamine. Newly synthesized histamine was still detectable at 48 and 72 hr of culture. Histamine synthesis was decreased by lwoering the concentration of histidine in the culture medium, and was markedly reduced by all the specific histidine dedarboxylase (HDC)3 inhibitors tested, but not by alpha-methyl-DOPA, pyrilamine maleate, or metiamide. Increasing the concentration of pyridoxal phosphate, the HDC coenzyme, above that normally present in culture medium resulted in only an equivocal increase in the amount of newly synthesized histamine, whereas aminoguanidine, an inhibitor of histaminase, had no detectable effect. Uptake of exogenous histamine by cultured basophils was trivial compared to histamine synthesis. Both newly synthesized and previously manufactured, nonisotopic, histamine seemed to be stored in the same pool, as the same proportion of both was released by concanavalin A (Con A). Cellular histamine was largely conserved, with little or no spontaneous release into the medium of detectable isotopic or nonisotopic histamine. These techniques provide a model for studying granulocyte metabolic processes in vitro, and should assist in the direct investigation of a variety of their physiologic functions.     

Sleep deprivation in the treatment of elderly depressed patients

Fifteen elderly depressed patients were treated by 36-hour sleep deprivation (SD). The depression was unipolar in 3 cases, bipolar in 3, and secondary in 4. Nine of the 15 patients responded to SD, and 6 had a remission (1 with SD alone and 5 with SD plus an antidepressant drug). Some of the remaining 6 patients might have responded if the treatment had not been interrupted for various reasons. These favorable results in elderly patients were better than anticipated. SD was well tolerated, although in one patient with bipolar depression a manic attack was precipitated. The effectiveness of SD poses interesting theoretic questions.     

Bone-marrow imaging in pure red blood cell aplasia

Bone-marrow scintigraphy with indium chloride in 111 was performed on a patient with pure red blood cell aplasia before and after successful treatment with immunosuppressive drugs. The return of erythroid precursors to the bone marrow was accompanied by a substantial increase in the marrow uptake of 111In. The distribution of 111In in the posttreatment scan was indistinguishable from that of 52Fe. These results indicate that indium chloride in 111 is a useful agent for the delineation of erythroid cellularity within bone marrow.     

The biosynthesis of human hemoglobin A1c. Slow glycosylation of hemoglobin in vivo

Hemoglobin A1c, the most abundant minor hemoglobin component in human erythrocytes, is formed by the condensation of glucose with the N-terminal amino groups of the beta-chains of Hb A. The biosynthesis of this glycosylated hemoglobin was studied in vitro by incubating suspensions of reticulocytes and bone marrow cells with [3H]leucine or 59Fe-bound transferrin. In all experiments, the specific activity of Hb A1c was significantly lower than that of Hb A, suggesting that the formation of Hb A1c is a posttranslational modification. The formation of Hb A1c in vivo was determined in two individuals who were given an infusion of 59Fe-labeled transferrin. As expected, the specific activity of Hb A rose promptly to a maximum during the 1st week and remained nearly constant thereafter. In contrast, the specific activity of Hb A1c and also of Hbs A1a and A1b rose slowly, reaching that of Hb A by about day 60. These results indicate that Hb A1c is slowly formed during the 120-day life-span of the erythrocyte, probably by a nonenzymatic process. Patients with shortened erythrocyte life-span due to hemolysis had markedly decreased levels of Hb A1c.     

Congenital musculoskeletal malformation in South African Blacks: a study of incidence

Ten thousand South African Black neonates were examined on the day after delivery for assessment of the frequency of congenital malformation of the musculoskeletal system. In 15 neonates it was found that the hip joints could be dislocated by the Ortolani or Barlow techniques. This instability persisted to 1 week of age in only 3 instances. This incidence figure is approximately 10% of the average reported for White's neonates. Talipes equinovarus deformity was found in 35 infants, an incidence of 3,5/1 000, or approximately three times the incidence cited for Whites. Calcaneovalgus deformity, however, was found in 3 infants only-- a much lower incidence than that found among Whites. There was a similar infrequency in the incidence of spina bifida aperta (cystica), which was noted in 7 infants. This figure correlates with reports from North America, but is substantially lower than the cited incidence in Wales and parts of England. Polydactyly, usually consisting of a postaxial pedunculated skin tag only, was the most common deformity found, the incidence being 8,8/1 000.     

Optical Absorption Glucose Measurements Using 2.3-$mu$m Vertical-Cavity Semiconductor Lasers

Continuous glucose monitoring has been shown to help diabetes mellitus patients stabilize their glucose levels, leading to improved patient health. One promising technique for monitoring blood glucose concentration is to use optical absorption spectroscopy. This letter proposes the use of thermally tunable 2.3-mum vertical-cavity surface-emitting lasers to obtain blood absorption spectra. The partial least squares technique is used to determine the glucose concentration from the spectra obtained in aqueous glucose solutions.