New antifungal therapy for children.
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Biomedical subjects
Publications and source records attributed to S Suarez.
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PURPOSE: To explore the use of triamcinolone acetonide phosphate liposomes as a pulmonary targeted drug delivery system. METHODS: Triamcinolone acetonide phosphate liposomes composed of 1,2-distearoyl phosphatidylcholine and 1,2-distearoyl phosphatidyl glycerol and triamcinolone acetonide 21-phosphate dipotassium salt were prepared by dispersion and extruded through polycarbonate membranes. Encapsulation efficiency and in vitro stability at 37 degrees C were assessed after size exclusion chromatography. TAP liposomes (TAP-lip) or TAP in solution (TAP-sol) were delivered to rats either by intratracheal instillation (IT) or intravenous (IV) administration. Pulmonary targeting was assessed by simultaneous monitoring of glucocorticoid receptor occupancy over time in lung (local organ) and liver (systemic organ) using an ex vivo receptor binding assay as a pharmacodynamic measure of glucocorticoid action. RESULTS: In vitro studies in different fluids over 24 hours, showed that more than 75% of the TAP remained encapsulated in liposomes. Cumulative pulmonary effects after IT administration of TAP-lip were 1.6 times higher than liver receptor occupancy. In contrast, there was no difference in the pulmonary and hepatic receptor occupancy time profiles when TAP was administered intratracheally as a solution. No preferential lung targeting was observed when TAP-lip was administered IV. As indicated by the mean effect times, lung receptor occupancy was sustained only when TAP-lip was administered IT. CONCLUSIONS: Intratracheal administration of TAP-lip provided sustained receptor occupancy, and increased pulmonary targeting which was superior to IT administration of TAP-sol or IV administration of TAP-lip. The use of liposomes may represent a valuable approach to optimize sustained delivery of glucocorticoids to the lungs via topical administration.
A DNA probe specific for genes coding for the heat-labile toxin type II (LT-II), heat-stable toxin type Ib (ST-Ib) and Shiga-like toxin type II (SLT-II), were used to examine 118 fecal Escherichia coli strains isolated from healthy pigs. Fifty-six (47.4%) of the isolated were hybridized with the LT-II probe. Thirty-nine strains (33%) possessed ST-Ib genes and five of the 118 isolates (4.2%) showed homology with the SLT-II DNA probe. E. coli that possessed unusual toxin genes for pigs were isolated with a high frequency, which indicates the importance of toxigenic clones found in nature. Uncommon virulence factors should be examined in order to improve the efficiency of diagnosis and control procedures.
Like interleukin-1, recombinant human tumor necrosis factor alpha (TNF alpha) has been found to decrease social exploration and induce weight loss in mice in a dose and time-dependent manner. The present study was carried out to study the interaction between these two cytokines. Mice were injected IP with subthreshold doses of TNF alpha (2.5 micrograms/mouse) and IL-1 beta (50 ng/mouse). Social exploration was decreased 2 and 4 h after injection of TNF and IL-1, but body weight was not affected. Subthreshold doses of TNF alpha (90 ng/mouse) and IL-1 beta (100 pg/mouse) were also injected intracerebroventricularly (ICV). Social exploration was decreased 1.5 and 3 h after injections of the two cytokines and body weight was decreased for 6 h. To test the possibility of central induction of IL-1 by TNF alpha, mice pretreated with IL-1 receptor antagonist (IL-1ra, 1.8 micrograms/mouse, ICV) were injected with 90 ng TNF alpha. Pretreatment with IL-1ra antagonized the depressive effect of TNF alpha on behavior, but had no effect on weight loss induced by this cytokine. These results suggest that TNF alpha-induced behavioral alterations are mediated by endogenously released IL-1, whereas metabolic changes are dependent on the release of other cytokines.
OBJECTIVE--To determine the prevalence of incipient and overt nephropathy in African-American subjects with non-insulin-dependent diabetes mellitus (NIDDM) attending a hospital clinic. Contributory factors, such as blood pressure (BP), duration and age at onset of diabetes, hyperglycemia, hyperlipidemia, and body mass index (BMI) also were evaluated. RESEARCH DESIGN AND METHODS--We recruited 116 African-American subjects with NIDDM for this cross-sectional, descriptive, and analytical study. BP, BMI, 24-h urine albumin excretion, creatinine clearance, serum creatinine, lipids, and GHb levels were measured. Albumin excretion rate (AER) was calculated, and subjects were divided into three groups: no nephropathy (AER < 20 micrograms/min), incipient nephropathy (AER 20-200 micrograms/min), and overt nephropathy (AER > 200 micrograms/min). Frequency of hypertension and nephropathy was analyzed by chi 2 testing, group means were compared using analysis of variance, and linear correlations were performed between AER and other variables. Multiple regression analysis was used to examine the association of these variables while controlling for the effects of other variables. RESULTS--Increased AER was present in 50% of our subjects; 31% had incipient and 19% had overt nephropathy. Hypertension was present in 72.4%; nephropathy, particularly overt nephropathy, was significantly more prevalent in the hypertensive group. Mean BP and diastolic blood pressure (dBP) were higher in the groups with incipient and overt nephropathy, and systolic blood pressure (sBP) was increased in overt nephropathy. Men with either form of nephropathy had higher sBP, dBP, and mean BP, whereas only women with overt nephropathy had increased sBP and mean BP. Subjects with incipient or overt nephropathy had a longer duration of diabetes, and those with overt nephropathy had a younger age at onset of diabetes. By multiple regression analysis, AER correlated with younger age at diabetes onset, but not with diabetes duration. No correlation with age, lipid levels, or GHb was noted. BMI correlated with AER. CONCLUSIONS--Incipient and overt nephropathy were observed frequently in these African-American subjects with NIDDM. Albuminuria correlated with BP, younger age at diabetes onset, and BMI. Association of albuminuria and increased cardiovascular mortality may place 50% of inner-city African-American patients with NIDDM at risk for developing cardiovascular complications.
Ejaculated boar sperm were incubated with explants of porcine oviductal mucosa that had been dissected from the isthmic and ampullar regions of gilts. Sperm bound within minutes to the epithelial surfaces of the explants. Binding was not affected by region (isthmus or ampulla) nor day of estrous cycle (Day 0 or Day 10), but was increased by addition of 70 pg/ml 17 beta-estradiol to the medium. Scanning electron micrographs indicated that sperm bound, via the acrosomal region, to ciliated cells. After 24 h, the numbers of bound sperm dropped significantly, but the motility of the bound sperm did not. A mucous material that entrapped sperm was observed on the epithelial surfaces of 23/32 isthmic and only 4/32 ampullar explants. These results indicate that sperm sticking to ciliated cells and mucus can create a sperm reservoir in the isthmus, but the means by which sperm are released remain unknown.
Escherichia coli strains of porcine origin express K88 and 987P pilus-antigens in vitro. This study reports their enterotoxin producing ability, serological features and plasmid content. The bipiliated strains were enterotoxigenic and all contained a large plasmid of uniform size.
Two-fold specificity in drug delivery obtained through the localized activation of drugs by physical means and the attachment of drugs to proteins that bind to target cells might be used for highly selective cancer chemotherapy or for immunosuppression. Toward this end, a monoclonal antibody against an antigen on the surface of T lymphocytes was covalently attached to liposomes containing a phototoxic drug, pyrene, bound to the lipid bilayer. When unfractionated peripheral blood lymphocytes, or B- and T-cell lines, were irradiated after treatment with these liposomes, T cells were killed while B cells were spared, demonstrating the validity of the approach in a simple in vitro assay.
Fertilization and early development in the horse were studied by recovering oviductal ova at various times after postovulatory mating. Ova collected between 7 and 22 h post coitum (pc) were examined for evidence of fertilizing sperm, cellular changes accompanying fertilization, and pronuclear development. Five ova collected between 7 and 9 h pc contained a marginal metaphase plate, but had no indication of sperm components; three of these, however, showed reduced numbers of cortical granules. Two activated ova (10 and 14 h pc) were in telophase of the second meiotic division, following incorporation of the fertilizing sperm. The fertilizing sperm was situated in a slight elevation; the nucleus was expanding but lacked a nuclear envelope. The pronuclear stage in the horse began as early as 12 h pc, and lasted at least until 21 h pc. Sperm tail remnants were seen in 5 of 7 pronuclear-stage ova, although the crowding of the cytoplasm with clusters of lipid and vacuoles made discerning sperm tail remnants difficult. The spindles of the metaphase stage of the second meiotic division were oriented radially, that is, at right angles to the cell surface, in all but one ovum, so this orientation is not a response to fertilization.
The ability of red blood cells (RBCs) to undergo an adaptation in shape that permits passage through the smallest vessels is reportedly impaired in diabetes. Several hypotheses have been proposed to explain decreased erythrocyte deformability, which has been implicated in the pathogenesis of microvascular complications, but the mechanisms responsible for this change have not been clearly delineated. In view of the fact that sorbitol accumulates in RBCs in diabetes and the postulate that increased sorbitol could alter deformability properties, we examined the influence of the aldose reductase inhibitor sorbinil on erythrocyte deformability. Erythrocyte deformability, determined as the volume of RBCs (VRBC) filtered per minute through 4.7-micron pore size filters, was significantly reduced in samples from diabetic rats compared with samples from controls (0.76 +/- 0.03 vs. 0.97 +/- .02 ml RBC/min; P less than .001). In contrast, deformability of RBCs from diabetic animals treated with sorbinil was significantly greater than in untreated diabetes, although not completely normalized (0.88 +/- 0.02; P less than .01 vs. diabetic, and P less than .02 vs. control). The reduced deformability characterizing cells from diabetic rats and its partial prevention by sorbinil persisted even when RBCs were washed to eliminate hyperglycemia and hyperviscous plasma. Thus, hyperviscosity per se is not responsible for the decreased deformability, and sorbinil can partially prevent this change despite persistent hyperglycemia. This effect may derive from sorbinil's action as an aldose reductase inhibitor and/or its ability to influence physicochemical properties of the erythrocyte membrane.
ADA is a key enzyme in the mammalian purine salvage pathway. The lack of ADA activity has been linked to a lack of cellular immunity in various immune and myeloproliferative disorders. Data on its role in patients with solid tumors are scant and inconclusive. In this report, we have evaluated the activity of this enzyme in the peripheral lymphocytes of patients with head and neck squamous cell cancer (HNC). The mean ADA activity in Stage IV patients (0.57 +/- 0.08 SEM, n = 12) was significantly lower than that of controls (1.55 +/- 0.25 SEM, P less than 0.05, n = 14) and also significantly lower that the mean ADA activity in patients with Stages I, II, and III (1.14 +/- 0.10 SEM, P less than 0.05, n = 17). Fourteen out of 19 controls, Stage I, II, and III patients had positive skin tests compared to 7 out of 10 Stage IV patients. These differences were not statistically significant. There was also no correlation between ADA activity and the absolute lymphocyte counts. Our results indicate that ADA activity in lymphocytes of patients with advanced HNC is lower than that of controls or patients with earlier stages of the disease. ADA may be a more sensitive indicator of suppressed cellular immunity than delayed cutaneous hypersensitivity reactions, or monitoring absolute lymphocyte counts.
We report a 2-month-old girl who developed bullous pemphigoid on her hands and feet shortly after receiving her routine immunizations. Infantile bullous pemphigoid has a clinical presentation distinct from bullous pemphigoid seen in older children and should be included in the differential diagnosis of blisters involving the hands and feet. Our patient responded well to topical corticosteroid therapy.