Retinoid-binding proteins in human oral mucosa

Vitamin A affects epithelial differentiation and growth via at least 3 different binding proteins. The specific delivery of extracellular retinol to target cells is performed by plasma retinol-binding protein (RBP) while cellular retinol- and retinoic acid-binding proteins (CRBP and CRABP) are implicated in the cellular action of the 2 natural retinoids. We have studied the levels of these 3 binding proteins by gel filtration and polyacrylamide electrophoresis in human oral mucosa, epithelium and chorion and compared it to those found in keratinizing human epidermis. The levels of CRABP in oral epithelium were markedly higher (about 4 times) than that of epidermis whereas CRBP was in a similar amount in epithelium chorion, dermis and epidermis. RBP with preserved affinity for retinol, was present in the epithelium of oral mucosa whereas only degraded RBP was detected in epidermis. These results suggest (i) a higher specific retinol delivery and (ii) a distinct cellular metabolism of retinoic acid in the oral epithelium as compared with epidermis. Since cornification occurs when keratinocytes are deprived of retinol, it might be that our observations are linked to the absence of cornification in the human oral mucosa. Further, high levels of CRABP in mucosal epithelium might have therapeutical implications because the synthetic retinoids used in human therapy bind to CRABP.

Static perimetry in canthaxanthin maculopathy

We performed threshold static perimetry on 19 patients who had ingested canthaxanthin; 11 had maculopathy and eight did not. Patients with no history of canthaxanthin ingestion served as controls. All patients had visual acuity of 6/9 or better. Threshold static perimetry was reevaluated two to three years after cessation of canthaxanthin ingestion. For both testing sessions, patients with maculopathy presented lower retinal sensitivity than controls, while patients without maculopathy did not differ significantly from the control group. These results suggest that canthaxanthin retinopathy can adversely affect the neurosensory retina.

Experimental infections of free-ranging Rocky Mountain bighorn sheep with lungworms (Protostrongylus spp.; Nematoda: Protostrongylidae)

Twelve free-ranging Rocky Mountain bighorn lambs (Ovis canadensis canadensis), each exposed experimentally to 125-1,000 infective third-stage larvae of Protostrongylus stilesi and P. rushi, shed significantly more first-stage larvae in their feces than did control lambs, but showed no clinical signs of illness and had equivalent summer and overwinter survival as control lambs. Two adult ewes, each exposed to 925 infective larvae, showed no increase in numbers of first-stage larvae in their feces; both survived at least 14 mo postexposure. Experimentally exposed lambs did not differ from control lambs in numbers of larvae in their feces in the following summer. Three experimental lambs had 313-402 adult P. stilesi and 0-97 adult P. rushi on necropsy; two control lambs had 255 and 270 P. stilesi and no P. rushi. The presence of these numbers of lungworms did not appear to be sufficient to precipitate lungworm pneumonia in bighorn lambs under the conditions of this study.

Modes of entry of first stage larvae of Protostrongylus stilesi and P. rushi (Nematoda: Metastrongyloidea) in the snail intermediate host Vallonia pulchella

First-stage larvae of Protostrongylus stilesi and P. rushi were able to infect the snail Vallonia pulchella both by penetrating the epithelium of the foot, the mantle, and probably the proboscis, and by penetrating the gut mucosa after being ingested by the snail.

The effect of temperature on rates of development of larval Protostrongylus spp. (Nematoda: Metastrongyloidea) from bighorn sheep, Ovis canadensis canadensis, in the snail Vallonia pulchella

The rate of development of Protostrongylus stilesi and (or) Protostrongylus rushi in the intermediate host Vallonia pulchella was related linearly to temperature between 10 and 30 °C. The temperature threshold was 8 °C and the thermal constant was 305 degree-days. Infected snails kept at 10 °C for several days and then transferred to 25 °C produced third-stage larvae faster than expected. Rates of development of Protostrongylus spp. applied to field conditions indicated that most of the first- to third-stage development occurs during the summer, very slow development takes place in the autumn or the spring, and none occurs over the winter. These data reinforce the hypothesis formulated by D. A. Boag and W. D. Wishart that snails on the bighorn sheep wintering grounds are responsible for transmission of the lungworms to sheep in autumn.

Induction of differentiation and inhibition of DNA methylation in HL-60 myeloid leukemic cells by 5-AZA-2'-deoxycytidine

The effects of 5-AZA-2'-deoxycytidine (5-AZA-CdR) on the induction of morphological and biochemical differentiation and inhibition of DNA methylation of human HL-60 myeloid leukemic cells were investigated. 5-AZA-CdR at concentrations of 0.1-1 microgram ml-1 for 48-h exposure produced significant morphological differentiation of HL-60 leukemic cells to a more mature phenotype, augmented the cell surface marker (OKMI) for mature granulocytes/monocytes and also increased the superoxide anion production. Under these same conditions 5-AZA-CdR inhibited the synthesis of 5-methylcytosine in DNA suggesting that there is a correlation between the induction of differentiation and inhibition of DNA methylation. At concentrations of 5-AZA-CdR that inhibit DNA methylation there was a marked decrease in colony-formation suggesting that the antileukemic action of this analog is related to the methylation of DNA.

Cell cycle effects and cellular pharmacology of 5-aza-2'-deoxycytidine

The cytotoxic action of 5-aza-2'-deoxycytidine (5-AZA-CdR) in synchronized cells and logarithmic- and plateau-phase cultures of EMT6 murine tumor cells was investigated. 5-AZA-CdR produced a greater cell kill of S phase cells than of cells in G1 phase. Cells in the logarithmic phase of growth were more sensitive to the cytotoxic effects of 5-AZA-CdR than cells in the plateau phase of growth. These results indicate that 5-AZA-CdR produces a preferential kill of cells in the S phase of the cell cycle. 5-AZA-CdR did not block the cell cycle progression of cells into S phase. The survival curve of EMT6 cells exposed to 5-AZA-CdR suggests that the cytotoxic action of this analogue is not self-limiting. The mutagenic activity of 5-AZA-CdR was investigated using induction of 6-thioguanine resistance in Chinese hamster ovary cells. 5-AZA-CdR was not a detectable mutagen in this assay system.

Comparison of the antileukemic activity of 5-AZA-2'-deoxycytidine, 1-beta-D-arabinofuranosylcytosine and 5-azacytidine against L1210 leukemia

The antineoplastic activity and effect on DNA synthesis and DNA methylation of 5-aza-2'-deoxycytidine (5-AZA-CdR), 1-beta-D-arabinofuranosylcytosine (ARA-C), and 5-azacytidine (5-AZA-CR) on L1210 leukemic cells were compared. At equimolar concentrations 5-AZA-CdR produced greater growth inhibition and more cytotoxicity against the L1210 cells than either ARA-C or 5-AZA-CR. ARA-C, but not 5-AZA-CdR or 5-AZA-CR, produced a potent inhibition of DNA synthesis in the L1210 cells. 5-AZA-CdR and 5-AZA-CR, but not ARA-C, inhibited DNA methylation with 5-AZA-CdR being a more effective inhibitor than 5-AZA-CR. At maximum tolerated dose, 5-AZA-CdR produced a much greater increase in life span of mice with L1210 leukemia than ARA-C or 5-AZA-CR. These in vitro and in vivo studies indicate that 5-AZA-CdR is a more potent antineoplastic agent against L1210 leukemic cells than either ARA-C or 5-AZA-CR.

Combinational chemotherapy of L1210 and L1210/ARA-C leukemia with 5-AZA-2'-deoxycytidine and beta-2'-deoxythioguanosine

The in vitro and in vivo antineoplastic activity of 5-AZA-2'-deoxycytidine (5-AZA-CdR) and beta-2'-deoxythioguanosine (TGdR) on L1210 and L1210/ARA-C (resistant to cytosine arabinoside) leukemic cells was investigated. 5-AZA-CdR was a very potent cytotoxic agent against the L1210 leukemia cells. This analogue was inactive against L1210/ARA-C leukemic cells because these cells lack deoxycytidine kinase, the enzyme that converts 5-AZA-CdR to its active nucleotide form. TGdR was a potent cytotoxic agent to both L1210 and L1210/ARA-C leukemic cells. In mice which were injected simultaneously with both L1210 and L1210/ARA-C leukemic cells, the drug combination of 5-AZA-CdR plus TGdR had a very potent antineoplastic activity and produced long-term survivors. Either agent alone did not produce any long-term survivors in the mice with L1210 and L1210/ARA-C leukemia. This experimental model indicates that 5-AZA-CdR plus TGdR is an interesting drug combination for the treatment of leukemia with drug-resistant cells.

The effect of early contact on maternal perception of infant behavior

The effect of extra maternal-infant contact during the first postpartum hour on maternal perception of infant behavior one month after delivery was measured by the Broussard Neonatal Perception Inventories and the attachment questions of Klaus and colleagues. All mothers were indigent primiparas who vaginally delivered normal, term infants. 60 mother-infant dyads were randomly assigned to either an extra contact or routine contact group. 49 mothers were available 1 month later for home visits. Scores on the Neonatal Perception Inventories were not significantly affected by either degree of contact or the sex of the child. There was also no difference between contact groups in the maternal response to the attachment questions. Infant behaviors recorded by 24 mothers during the 4 days following home visits were similar in the 2 contact groups. Mothers reported significantly more negative behaviors for female than for male infants. Any effects of extra contact during the first hour after birth on maternal-infant interaction are unlikely to result from changes in maternal perception of infant behavior.

Neutrophil function in Bartter's syndrome

Bartter's syndrome is a state associated with hyperprostaglandinemia and high urinary excretion of prostaglandin derivatives. Because of numerous reports on prostaglandins acting as local modulators of the immune system, we have studied parameters of phagocytic function and of cellular and humoral immunity in four patients with this disease. An augmentation in chemotaxis was identified in Bartter's syndrome neutrophils. Despite some minor deviations in other parameters measured, no other gross derangement in immune function could be identified.

[Early detection of pemphigus vulgaris: role of the dentist]

Means to detect pemphigus vulgaris at an early stage are described. Its grave evolution in absence of treatment makes an early diagnosis imperative. The first signs are frequently localized in the oral mucosa and sometimes the disease remains confined to this mucosa only. Efficient and early therapy may favourably influence the course of disease, and the dentist is in a prime position to detect the characteristic lesions.

[Chronic granulomatous disease (CGD): in vitro enhancement of bactericidal activity of CGD phagocytes by rifampicin]

In a series of 29 experiments on CGD patients, we have studied the in vitro bactericidal capacity of normal and CGD phagocytes against penicillin, streptomycin and rifampicin sensitive Staphylococcus aureus. The bactericidal activity of phagogyte preparations was tested at different intervals during a 21 hour incubation. The CGD-phagocyte bactericidy peaks after 90 min when penicillin is used; in contrast, a significant enhancement of the bactericidal activity is noted with rifampicin and best noted after 21 hours of incubation. To elucidate the mode of action of this antibiotic, a rifampicin resistant S. aureus was used in a series of experiments; The results point to a mixt type of action: antimicrobial and metabolic.