Showing papers by "Central Drug Research Institute published in 1974"

Absorption and Excretion of 2,4-Dichlorophenoxyacetic Acid in Man

Abstract: 1. Absorption and urinary excretion of 2,4-dichlorophenoxyacetic acid (2,4-D) have been studied in six subjects following oral ingestion (5 mg/kg).2. 2,4-D is quickly absorbed; significant quantities were detected in plasma 1 h after ingestion.3. 75% of the administered dose of 2,4-D is excreted unchanged in the urine in 96 h after administration.4. Lack of metabolic transformation and rapid excretion suggest that cumulative toxicity by 2,4-D is unlikely.

Preliminary experience with cell culture of human articular chondrocytes.

Abstract: Articular Chondrocytes from 14 human amputation specimens were grown in monolayer culture. The joint cartilages appeared normal grossly. The ages of the patients ranged from 13 to 62 years. The cells grew slowly and did not thrive in subculture. Vitamin C increased DNA synthesis by the Chondrocytes but decreased incorporation of radiosulfate into mucopolysaccharides. Whole articular cartilage from a 30 year old man showed a great heterogeneity of mucopolysaccharides. In addition to the expected chondroitin sulfates 4 and 6 and keratan sulfate, appreciable quantities of hyaluronate, chondroitin, disulfated chondroitin and dermatan sulfate were found (4.0%, 1.5%, 25.5% and 1.3% of the total mucopolysaccharides respectively). The same compounds were secreted into the medium by the cultured Chondrocytes but in distorted proportions. These and other findings differ greatly from those obtained with rabbit Chondrocytes which grow readily under the same conditions and recapitulate quite faithfully the mucopolysaccharide synthesis occurring in whole cartilage.

Role of human skin in the photodecomposition of bilirubin.

Abstract: 1. Human skin epithelium and human skin were found to absorb both free bilirubin and serum-bound bilirubin from an aqueous buffered medium. The serum-bound bilirubin thus absorbed was readily released when human skin epithelium or human skin were transferred to media containing no bilirubin. 2. The Km values for serum-bound bilirubin were 1.8×10−3m and 2.2×10−3m respectively for human skin epithelium and human skin; corresponding Km values for free bilirubin were 3.0×10−4m and 5×10−4m. The Vmax. for bound and free bilirubin was of the same magnitude, the apparent Vmax. being 1.0 and 1.66μmol/g of tissue for human skin epithelium and human skin respectively. 3. When human skin that had acquired a yellow tinge by absorbing bilirubin was incubated in a buffered medium and exposed to a mercury-vapour light, the yellow colour disappeared and decomposition products of bilirubin accumulated in the medium. 4. Experiments with [3H]bilirubin indicated that the pigment absorbed by skin was photo-oxidized to products that were soluble in water and the quantity and number of such products increased with the time of exposure of human skin to the light-source. Under similar conditions [3H]bilirubin alone in buffered medium was also oxidized and gave products which by paper chromatography appeared to be different from those released by human skin that had absorbed bilirubin. 5. The results suggest that by virtue of its large surface area human skin can act as a matrix for the degradative action of light on bilirubin.

Study of Naegleria aerobia by electron microscopy.

Abstract: Ultrastructural differences in N. aerobic grown in culture and from infected mouse brain have been studied. 1. 1. The amoebae in culture were more irregular in outline. The cytoplasm contained dark stained mitochondria and free-ribosomes along with other cytoplasmic organelles. The cytoplasm of some of the amoebae contained membrane bound black bodies. 2. 2. The cytoplasm of the amoebae in brain tissue contained predominantly lightly stained mitochondria, polydribosomes and lightly stained membrane bound reserve food vacuoles. 3. 3. The clear space around the amoebae in the host tissues and the myelinated structure in the food vacuoles suggest both extracellular digestion and phagocytic activity of the pathogen respectively.

Ultrastructural changes during encystment of Schizopyrenus russelli.

Abstract: SYNOPSIS Ultrastructural changes associated with the encystment of Schizopyrenus russelli have been studied by electron microscopy. Before encystment small “black bodies” appear in the cytoplasm and later migrate toward the periphery. The outer cyst wall is secreted at this stage as a thin discontinuous layer which thickens and subsequently becomes continuous. Concomitant with this, the endoplasmic reticulum surrounds the mitochondria. The inner cyst wall later appears as a multilayered structure which presumably is cast off from the plasma membrane. Between the inner and outer layers of the cyst wall, there is a middle, less electron-dense layer wherein extruded cytoplasmic material is found embedded at certain places.

Recent advances in cytochemistry and ultrastructure of cytoplasmic inclusions in Ciliophora (Protozoa).

Abstract: Publisher Summary This chapter discusses the recent developments in the field of cytochemistry and ultrastructure of cytoplasmic inclusions in ciliates (subphylum Ciliophora) The available electron microscope evidence shows the presence of acid phosphatase-rich Golgi dictyosomes in ciliates The Golgi nature of these dictyosomes in Paramecium is confirmed by the presence of thiamine pyrophosphatase within the Golgi saccules Mitochondria show normal tubular cristae in most free-living ciliates In ciliates living under anaerobic conditions, the cristae undergo reduction In forms such as Ngctotherus and Balantidium, which live in the intestine under partial anaerobic conditions, the cristae are reduced to two to three per mitochondrion, while in ciliates belonging to Isotrichidae and Ophryoscolecidae, which live under complete anaerobic conditions in the intestine, the cristae are more or less lacking The mucocysts that occupy a cortical position beneath the pellicle of ciliates initially develop in the endoplasmic region They function as mucus-secreting organelles Mucus has been reported to help in gluing food particles together to facilitate their ingestion, provide sticky material for thigmotactism, play an important role in the development of cyst membranes, and concentrate nutrients from the surrounding medium prior to uptake Like the mucocysts and clathrocysts, the trichocysts of Frontonia vesiculosa and Paramecium caudatum also have an endoplasmic origin In flagellates, the trichocysts appear to develop from the Golgi complex In ciliates, however, no such relation with the Golgi complex has been found

Growth Inhibition of Enteric Bacteria by Vibrio cholerae in Nutrient Media Containing Lactate, Acetate, or Citrate

Abstract: In cross-streak tests on nutrient agar containing lactate, acetate, or citrate, the growth of certain enteric bacteria was inhibited by themselves or by Vibrio cholerae, or by both. This mimicked the activity of bacteriocins, but the phenomenon was attributable to the accumulation of carbonate and increased alkalinity of the media.

Ultrastructural differences of Hartmannella culbertsoni singh and DAS, 1970, in mouse brain and under different cultural conditions

Abstract: 1. 1. Outlines of the amoebae in mouse brain were more or less rounded, whereas the amoebae from axenic and monobacterial cultures were irregular in outline. 2. 2. Darkly stained membrane-bound globular reserve food materials were present only in the cytoplasm of amoebae in the brain tissue. 3. 3. Electron dense mitochondria were characteristic of amoebae in axenic culture. Mitochondria in amoebae in both mouse brain and in cultures associated with bacteria appeared lightly stained. 4. 4. Many Golgi zones were observed in amoebae from both monobacterial cultures and those from mouse brain while amoebae in axenic cultures showed these organelles less frequently. 5. 5. Spongiome was frequent in the cytoplasm of both axenically and monoxenically grown amoebae but was less frequent in the amoebae from mouse brain. 6. 6. Multivesicular organelles were commonly present in the cytoplasm of the amoebae associated with bacteria in cultures. These organelles were, however, absent in amoebae obtained from brain tissues and from axenic culture. 7. 7. Food vacuoles containing bacteria were present in the cytoplasm of the amoebae of monobacterial cultures whereas pinocytic food vacuoles were present in the cytoplasm of both the amoebae of axenic culture and in mouse brain. 8. 8. Ultrastructural characteristics for Acanthamoeba sp. by VICKERMAN (1962) and for A. castellanii by BOWERS and KORN (1968) were compared with ultrastructural details observed in H. culbertsoni.