Illicit drug injectors in three Texas cities

In three Texas cities illicit drug injectors not in treatment were located by outreach and interviewed with a standard questionnaire. In all the cities the drug injectors were predominantly undereducated and unemployed young men from minority groups. In Dallas and Houston most were Black, while in San Antonio most were Hispanic. The most frequently reported primary drug in Houston was cocaine, but in Dallas and San Antonio it was heroin. The high needle risk for AIDS and the low rates of positive HIV antibody tests in these samples present a special window of opportunity for prevention of AIDS.

Visualizing the distribution of elements within barley leaves by energy dispersive X-ray image maps (EDX maps)

X-ray image maps of transverse sections of barley leaf blades were compared with individual X-ray emission spectra from vacuoles of barley leaf mesophyll, epidermis and parenchymatous bundle sheath cells. Both forms of X-ray analysis revealed distinct patterns in element distribution within the leaf blade. Calcium and Cl predominated within the epidermal cell vacuoles whilst P appeared mainly in the mesophyll cell layer. Apparent accumulation of S and Mg within the bundle sheath cell vacuoles is discussed in relation to xylem unloading and sulphur assimilation.

A preliminary ethnographic decision tree model of injection drug users' (IDUs) needle sharing

This article presents a preliminary ethnographic decision tree model of the needle sharing and HIV risk decision-making processes common to injection drug users (IDUs) in Houston, Texas. Ethnographic tree decision modeling is a rigorous qualitative method used to understand and predict how and why people in certain groups do things the way they do. The model was developed from data collected from focus group and individual interviews and naturalistic observations. The research participants were White, African-American and Latino male and female IDUs. The model presents IDUs' needle-sharing routines or scripts based on several prioritized criteria. The model supports other researchers' findings that social roles play an important part in shaping IDUs' needle sharing. Yet, the model attempts to specify the different kinds of roles and relationships. The model suggests that social roles IDUs play and the status hierarchy between roles are the translation mechanisms that organize IDUs' social relationships into drug and HIV risky activities.

Lipid supplemented medium induces lamellar bodies and precursors of barrier lipids in cultured analogues of human skin

Barrier function of cultured skin substitutes (CSS) is required for their effective use in clinical treatment of skin wounds, and for percutaneous absorption in vitro. Arachidonic, palmitic, oleic, and linoleic free fatty acids, in conjunction with the antioxidant alpha-tocopherol acetate (lipid supplements, "LS"), were added to nutrient media of CSS to provide precursors of epidermal barrier lipids. CSS were composed of human keratinocytes (HK), fibroblasts (HF), and collagen-glycosaminoglycan substrates, and were incubated for 14 d submerged or lifted to the air-liquid interface in media based on MCDB 153 +/- LS. Duplicate samples (30 cm2) were harvested and the epidermal analogue was analyzed for total protein, total DNA, total lipid, lipid fractions including acylglucosylceramide (AGC), and presence of lamellar bodies. Significant increases (p < 0.05) were detected between CSS incubated in +LS medium for total lipid, total DNA, ceramide, glucosylceramide, triglycerides, and diglycerides. AGC and lamellar bodies were detected only in epithelia of CSS incubated in +LS medium. These data show that free fatty acids, vitamin E, and lifting of CSS promote increased epithelial morphogenesis compared to CSS cultured submerged without lipid supplements. Presence of lamellar bodies and AGC suggests enhanced production in vitro of barrier-associated epidermal lipids.

Glucocorticoids accelerate fetal maturation of the epidermal permeability barrier in the rat

The cutaneous permeability barrier to systemic water loss is mediated by hydrophobic lipids forming membrane bilayers within the intercellular domains of the stratum corneum (SC). The barrier emerges during day 20 of gestation in the fetal rat and is correlated with increasing SC thickness and increasing SC lipid content, the appearance of well-formed lamellar bodies in the epidermis, and the presence of lamellar unit structures throughout the SC. Because glucocorticoids accelerate lung lamellar body and surfactant maturation in man and experimental animals, these studies were undertaken to determine whether maternal glucocorticoid treatment accelerates maturation of the epidermal lamellar body secretory system. Maternal rats were injected with betamethasone or saline (control) on days 16-18, and pups were delivered prematurely on day 19. Whereas control pups exhibited immature barriers to transepidermal water loss (8.16 +/- 0.52 mg/cm2 per h), glucocorticoid-treated pups exhibited competent barriers (0.74 +/- 0.14 mg/cm2 per h; P < 0.001). Glucocorticoid treatment also: (a) accelerated maturation of lamellar body and SC membrane ultrastructure; (b) increased SC total lipid content twofold; and (c) increased cholesterol and polar ceramide content three- to sixfold. Thus, glucocorticoids accelerate the functional, morphological, and lipid biochemical maturation of the permeability barrier in the fetal rat.

Preservation of permeability barrier ontogenesis in the intrauterine growth-retarded fetal rat

The epidermal permeability barrier is provided by intercellular lipids forming multiple membrane bilayers in the stratum corneum. In the fetal rat, the barrier to transepidermal water loss forms during the 20th d of gestation and is accompanied by 1) increasing stratum corneum thickness; 2) increasing stratum corneum lipid content, particularly nonpolar ceramide and cholesterol content; and 3) the formation of lamellar unit structures throughout the stratum corneum interstices. In this report, we demonstrate that among pups of 20 d gestational age increasing barrier competence is correlated with increasing fetal weight. It has been previously demonstrated that fetal rats subjected to intrauterine growth retardation (IUGR) exhibit a thinner stratum corneum and decreased content of differentiation-specific epidermal structural proteins. To determine whether IUGR fetal rats also exhibit immaturity of barrier function and the barrier membrane system, maternal rats underwent unilateral uterine vessel ligation on d 17 or 18 of gestation and IUGR and control littermates were harvested on d 20, 21, or 22 of gestation for determination of transepidermal water loss. Despite significant somatic growth retardation and a thinner stratum corneum, barrier function in IUGR fetal rats did not significantly differ from that in control littermates at any gestational age. In both IUGR and control fetal rat epidermis at 21 d gestational age, lipids were deposited in a membrane pattern as visualized by nile red fluorescence microscopy and formed lamellar unit membrane structures throughout the stratum corneum intercellular domains as observed by electron microscopy.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathobiology of the stratum corneum

The epidermis is a dynamic system whose metabolic activity is regulated in large part by the integrity of the permeability barrier. This barrier resides in the stratum corneum and comprises a unique 2-compartment system of structural protein-enriched corneocytes embedded in a lipid-enriched intercellular matrix. Lipid extraction or metabolic imbalances, such as essential fatty acid deficiency, produce barrier abnormalities that in turn result in epidermal hyperproliferation, scaling, and inflammation. When the barrier remains intact, lipid imbalances, such as an abnormal cholesterol sulfate:cholesterol ratio in recessive X-linked ichthyosis, can lead to abnormal corneocyte adhesion (visible scale). Both cellular and intercellular proteins also participate in normal desquamation, and protein abnormalities may provoke abnormal scaling (such as filaggrin in ichthyosis vulgaris). Thus, perturbations of the stratum corneum may be the catalyst for a number of skin diseases, rather than the end result of processes that are initiated in subjacent skin layers.

Dermatitis in treated maple syrup urine disease

Two children who had classic maple syrup urine disease developed an eruptive dermatitis when plasma isoleucine levels, leucine levels, or both fell below normal during periods of protein restriction. The dermatitis was resistant to topical corticosteroid therapy. Rapid resolution occurred after treatment with isoleucine and leucine dietary supplements.

The general solution to the Bloch equation with constant rf and relaxation terms: application to saturation and slice selection

The general solution to the Bloch equation in the rotating frame which includes the effects of relaxation during a constant amplitude, off-resonance rf field has been developed. The solution is used to monitor the transient approach to steady-state saturation levels during off-resonance irradiation applied continuously or in pulses to systems with arbitrary relaxation rates. The time course of the magnetization during amplitude modulated rf pulses is followed with the general solution and the transverse relaxation time dependence of typical slice profiles is examined. The calculations serve to illustrate the generality of the solution. A thorough discussion of various computational concerns is provided.

High-affinity fatty acid-binding activity in epidermis and cultured keratinocytes is attributable to high-molecular-weight and not low-molecular-weight fatty acid-binding proteins

Fatty acid-binding proteins (FABPs) are abundant low-molecular-weight cytosolic proteins in tissues involved in fatty acid (FA) metabolism. Because epidermis is also an active lipogenic tissue, we examined cytosols from murine and porcine epidermis and cultured human keratinocytes and fibroblasts for FABPs. High-affinity FA-binding activity was present in both epidermis and differentiated keratinocytes, whereas no high-affinity FA-binding activity was found in cultured human fibroblasts or undifferentiated keratinocytes. By column chromatography, a single binding peak was identified in the high (90-100 kDa)-molecular-weight range and no binding activity was evident in the low (14-15 kDa)-molecular-weight range, where conventional FABPs elute. Moreover, rabbit anti-rat heart FABP, anti-rat intestine FABP, and anti-rat liver FABP antisera did not identify proteins in the 14-15-kDa range in murine epidermal cytosol by Western immunoblots, whereas the anti-rat-heart antibody recognized a protein of approximately 32 kDa. Isoelectric focusing of differentiated keratinocyte cytosol demonstrated a single FA-binding peak having a pI of approximately 4.0. Analysis of this binding peak by SDS-PAGE revealed peptides of approximately 66 and 38 kDa. These findings suggest the possibility that the FA-binding protein in keratinocyte cytosol normally exists as a heterodimer. Western immunoblots of both differentiated keratinocyte cytosol and keratinocyte-conditional media stained with a rabbit anti-human serum albumin antibody identified a protein of approximately 67 kDa, but the electrofocused fraction did not react with this antibody. Thus, epidermis and differentiated keratinocytes possess high-affinity cytosolic FA-binding activity that cannot be ascribed either to conventional low-molecular-weight FABPs or to albumin.

Synthesis and Properties of 6A-Amino-6A-deoxy-α and β-cyclodextrin

The monotosylates obtained by treatment of α- and β- cyclodextrin with p- methylbenzenesulfonyl chloride reacted with ammonia to give the title compounds. These amines are of unusually low basicity , with pKa values of 8.70 and 8.72, respectively. In water at 25°, the hydrochloride salt of the amine derived from β- cyclodextrin is approximately 40 times more soluble than β-cyclodextrin and, through complexation, the salt increases the solubility of Nabumetone over 800 times.

Membrane structural abnormalities in the stratum corneum of the autosomal recessive ichthyoses

Congenital ichthyosiform erythroderma (CIE) and classic lamellar ichthyosis (LI) are autosomal recessive disorders of cornification (DOC), distinguished previously by clinical, histologic, ultrastructural, and cell kinetic criteria. Whether there is further heterogeneity within the CIE group is uncertain. To address the issue of genetic heterogeneity, and to study the pathogenesis of these DOC, skin biopsies from eight CIE, three LI, and six normal subjects were assessed by electron microscopy, including ruthenium tetroxide postfixation with optical diffraction, to visualize and quantitate intercellular membrane domains. We found abnormal lamellar bodies in CIE and distinctive alterations in intercellular lamellar bilayer architecture among patients with CIE and three patients with LI. Two biopsies from two patients at different sites demonstrated the consistency of these findings. Moreover, in both CIE and the three LI patients, desmosomes persisted throughout the outer layers of the SC, indicative of impaired degradation. Our ultrastructural observations support the previously reported phenotypic distinction between CIE and LI, and the further likelihood of genetic heterogeneity within CIE. However, these studies do not support the division of the autosomal recessive ichthyoses into three subgroups based upon cytosolic structural abnormalities. Finally, these studies provide new insights into the pathogenesis of the autosomal recessive DOC.

Ichthyosis: mechanisms of disease

The disorders of cornification (ichthyoses) comprise acquired and inherited disorders characterized clinically by generalized scaling and histologically by hyperkeratosis. They may arise through defects in the production or maintenance of a normal cornified cell compartment, or both. The stratum corneum is composed of protein-enriched and lipid-depleted corneocytes ("bricks") surrounded by an intercellular domain ("mortar") composed of hydrophobic, lipid-enriched membrane bilayers, and containing desmosomes and a limited array of hydrolytic enzymes. Mechanisms whereby a genetic defect involving either the bricks or the mortar may result in abnormal stratum corneum retention are discussed using ichthyosis vulgaris and recessive X-linked ichthyosis as examples. In addition, epidermal hyperproliferation, which floods the cornified cell compartment with incompletely formed units, results in hyperkeratosis. To date, no primary disorders of epidermal hyperproliferation have been defined. Recent work, however, demonstrates that stratum corneum barrier function regulates epidermal DNA synthesis. For example, in essential fatty acid deficiency, barrier dysfunction is responsible at least in part ror the epidermal hyperproliferation. Defective barrier function due to defective lamellar body secretion may also underlie the phenotypic changes after birth in harlequin ichthyosis; that is, from the massive, constrictive hyperkeratosis of the newborn to an exfoliative erythroderma in survivors. The mechanisms whereby specific defects in cornification result in generalized scaling disease are only beginning to be defined. Yet, even at this early stage, the view of the stratum corneum as a tightly organized structure whose function is highly regulated is emerging. Hence, the disorders of cornification should provide important insights into stratum corneum structure and function.

Peroxisomal abnormality in fibroblasts from involved skin of CHILD syndrome. Case study and review of peroxisomal disorders in relation to skin disease

BACKGROUND AND DESIGN

Peroxisomal deficiency has been described in a number of syndromes characterized by chondrodysplasia punctata, including the Conradi-Hünermann (C-H) syndrome. Because of overlapping clinical features of X-chromosome inheritance, ichthyosis, and limb-reduction defects in C-H and CHILD (congenital hemidysplasia with ichthyosiform erythroderma and limb defects) syndromes, we examined peroxisomal content using diaminobenzidine cytochemistry and peroxisomal functions in fibroblasts from involved vs uninvolved skin of CHILD syndrome.

RESULTS

Fibroblasts from involved skin of a patient with CHILD syndrome accumulated cytoplasmic lipid, visualized with the fluorescent probe, nile-red. Ultrastructurally, fibroblasts of involved skin of CHILD syndrome accumulated lamellated membrane and vacuolar structures. By diaminobenzidine ultracytochemistry, fewer peroxisomes were present. Moreover, the activities of two peroxisomal enzymes, catalase and dihydroxyacetone phosphate acyltransferase, were decreased (approximately 30% of normal). However, peroxisomal oxidation of very-long-chain and branched-chain fatty acids was preserved. Moreover, plasma very-long-chain fatty acids, plasma phytanic acid, and erythrocyte plasmalogen content were normal.

CONCLUSIONS

The CHILD, C-H, and rhizomelic chondrodysplasia punctata syndromes are all characterized by ichthyosis, chondrodysplasia punctata, and limb defects, as well as peroxisomal deficiency. Thus, these syndromes may be related pathogenically. Because peroxisomes are involved in prostaglandin metabolism, peroxisomal deficiency may directly contribute to the previously reported alterations in prostaglandin metabolism in fibroblasts of involved skin of fibroblasts.

Exogenous origin of n-alkanes in pathologic scale

BACKGROUND

Although n-alkanes accumulate in some disorders of cornification, recent studies using radioactive carbon 14 content by accelerator mass spectrometry point to an exogenous origin for alkanes in normal stratum corneum, and their derivation in congenital ichthyosiform erythroderma remains controversial.

DESIGN AND RESULTS

Using 14C content to measure sample age, the n-alkane fractions from two patients with congenital ichthyosiform erythroderma contained no detectable contemporary materials. By electron microscopy, alkane-enriched emollients (petrolatum [Vaseline]) permeated to all levels of stratum corneum of hairless mice, expanding the intercellular domains and distorting membrane bilayers. Similar ultrastructural changes were also observed in the stratum corneum of patients with congenital ichthyosiform erythroderma. When alkanes were excluded, no differences in lipid content were evident between two forms of autosomal recessive ichthyosis.

CONCLUSIONS

These data demonstrate that scale n-alkanes in disorders of cornification derive from environmental sources and indicate the pervasiveness of petroleum-based emollients in skin. Therefore, epidermal lipid analyses must be interpreted with caution. However, these studies do not rule out an important therapeutic and/or pathogenic role for exogenous n-alkanes in skin.

An algorithm for selecting a communication technique with intubated patients

Communicating with intubated patients in the intensive care unit is a frequent and frustrating situation. In order to communicate effectively, nurses need to select from a variety of communication techniques. The author presents an algorithm which guides the nurse in choosing the most effective communication technique for each patient.

Epidermal lipids and scaling diseases of the skin

Alterations in epidermal lipid content or metabolism underlie several scaling diseases of the skin in man and experimental animals. The importance of cholesterol to epidermal homeostasis and normal desquamation is demonstrated by the scaling disorder produced by topical applications of lovastatin in experimental animals, and by the imbalance of the cholesterol sulfate:cholesterol ratio in stratum corneum in patients with recessive X-linked ichthyosis. The essential fatty acid-deficient rodent illustrates the importance of linoleic acid to epidermal function. Finally, a defect in lamellar body organellogenesis may underlie harlequin ichthyosis.

Ontogeny of the epidermal barrier to water loss in the rat: correlation of function with stratum corneum structure and lipid content

The mammalian epidermal permeability barrier is provided by highly hydrophobic lipids forming multiple membrane bilayers within the extracellular domains of the outer, cornified cell layers. To characterize the critical events associated with barrier maturation, we correlated the emergence of a competent barrier to transepidermal water loss with development of the lamellar body secretory system, the organization of stratum corneum membrane bilayers, and the lipid composition of these membranes in the perinatal rat. Whereas pups of 19 d estimated gestational age had no measurable barrier (transepidermal water loss greater than 10 mg/cm2/h), by 21 d the barrier was well established (mean transepidermal water loss 0.41 mg/cm2/h). Development of a functional barrier correlated with increasing thickness of the stratum corneum, as well as with development of a membrane pattern of lipid deposition, visualized with the hydrophobic fluorescent probe nile red. At 19 d estimated gestational age, the stratum corneum intercellular domains exhibited an abundance of secreted lamellar body contents, but they were not organized into basic bilayer unit structures. Lamellar unit structures became evident by 20 d and extended throughout the stratum corneum interstices by 22 d (term). The quantity of lipid in isolated stratum corneum increased significantly between 19 and 20 d (34.08 versus 50.08 mean micrograms lipid/cm2, respectively; p less than 0.02) and still further between 20 and 21 d estimated gestational age (74.49 micrograms lipid/cm2; p less than 0.001). This increase was due to progressive accumulation of neutral lipids, particularly cholesterol, as well as nonpolar ceramides, as shown by thin-layer chromatography/scanning densitometry. These studies imply that in the development of cutaneous barrier function in the fetal rat both the generation of sufficient quantities of hydrophobic lipids and the organization of these lipids into bilayer unit structures are required.

Lamellar bodies as delivery systems of hydrolytic enzymes: implications for normal and abnormal desquamation

Lamellar body secretion results in the delivery of a selected array of hydrolytic enzymes to the extracellular domains of stratum corneum (SC). Deposition and activation of these enzymes in the interstices presumably is associated with the transformation of lamellar body-derived lipids from a relatively polar to a non-polar mixture, as well as the degradation of other non-lipid intercellular substrates. To determine whether abnormal desquamation might result from failure of hydrolytic enzyme delivery to the SC interstices, we localized one catabolic enzyme, acid lipase, previously shown to be a reproducible marker for the lamellar body secretory system, by cytochemical methods within the epidermis of selected human (congenital ichthyosiform erythroderma, CIE) and animal (essential fatty-acid deficient (EFAD) mouse epidermis and mouse tail epidermis) models associated with abnormal scaling or unusual SC retention. In addition, we compared the persistence of desmosomes within normal SC vs. the various models. Normal human and murine epidermis displayed abundant lipase activity both in lamellar bodies (LB) and in association with secreted lamellar body contents in the SC interstices. Despite normal quantities of LB in CIE, EFAD, and mouse tail epidermis, lipase activity was markedly deficient both in LB and in the SC intercellular domains. These studies support the hypothesis that normal desquamation is mediated by enzymatic modulations in lipid and/or protein content of the SC interstices, and that some forms of pathological or excessive scaling may be due to desmosomal persistence that results from defective or limited delivery of lamellar body-derived, hydrolytic enzymes to the SC intercellular domains.

HMG-CoA reductase inhibitors perturb fatty acid metabolism and induce peroxisomes in keratinocytes

Topical lovastatin stimulates epidermal fatty acid synthesis in vivo; therefore, studies were undertaken to examine the effects of HMG-CoA reductase inhibitors on fatty acid metabolism in cultured keratinocytes. When exposed to fluindostatin or lovastatin for greater than or equal to 24 h, keratinocytes in serum-free media accumulated nile red-fluorescent lipid droplets. By 72 h, the triacylglycerol and phospholipid content were increased 2.5- and 1.3-fold, respectively. Reductase inhibitors (1-10 microM) increased fatty acid synthesis approximately 1.5-fold; increased synthesis was noted only after greater than 15 h exposure and was distributed among phospholipids and triacylglycerols. Oxidation of [14C]palmitate to CO2 was decreased greater than 50% in inhibitor-treated cultures, and label accumulated in triacylglycerols. Inhibitor-treated keratinocytes exhibited increased numbers of peroxisomes, using diaminobenzidene ultracytochemistry. Peroxisomal hyperplasia was also demonstrated by increased catalase activity (1.5- to 2.5-fold), increased dihydroxyacetone phosphate acyltransferase activity (1.4-fold) and increased peroxisomal (KCN-insensitive) fatty acid oxidation (1.4-fold) in inhibitor-treated cultures. Thus HMG-CoA reductase inhibitors increase fatty acid synthesis, induce triacylglycol and phospholipid accumulation, and induce peroxisomes in cultured keratinocytes. Coincubations with either low density lipoproteins or 25-hydroxycholesterol prevented both the peroxisomal hyperplasia and increased fatty acid synthesis, suggesting that these effects of reductase inhibitors may be linked to their effects on the cholesterol biosynthetic pathway.

Intergenerational differences in i.v. drug use behaviors: implications for HIV prevention

The spread of the human immunodeficiency virus through the IV-drug-using population poses a serious public health threat. The tendency is to consider one IV drug user much the same as another. However, there are likely subtle differences in the behaviors of IV drug users depending on sexual, ethnic, and age differences. This study looks at the IV-drug-using behaviors of young adults 18 to 25 and adults over the age of 40. The drugs injected and rates of injection do differ for the two groups. This would suggest that HIV prevention should be tailored in response to the age differences of the targeted drug users.