Intermolecular electron-transfer catalyzed on nanoparticle surfaces

Surface-functionalized nanoparticles enhance the rate of electron transfer (ET) between Cyt c(Fe(2+)) and Co(phen)(3)(3+) by a factor of 10(5) through simultaneous electrostatic binding of an ET donor and acceptor.

Nickel-ion-mediated control of the stoichiometry of his-tagged protein/nanoparticle interactions

The interaction between synthetic materials and biomolecules plays an important role in biomedical and pathological sciences. An important issue in these interactions is control of stoichiometry. The interaction between NTA ligands and proteins with six consecutive His residues has been widely used for protein purification. Control of stoichiometry is an important issue in applying this recognition strategy to the creation of defined nanoparticle-protein conjugates. In this communication we report the direct control of particle-protein stoichiometry through variation of nickel chloride concentration, as demonstrated through fluorescence and gel electrophoresis.

Dendron-based model systems for flavoenzyme activity: towards a new class of synthetic flavoenzyme

Three generations of water-soluble flavin dendrons have been synthesized and the role dendrimer generation has on the physical and catalytic properties of these assemblies has been investigated.

Pulmonary hypertension in children and adolescents with sickle cell disease

The prevalence of pulmonary hypertension (PHTN) in the pediatric sickle cell disease (SCD) population is not known despite its high prevalence in adult patients. Our hypothesis was that increased pulmonary artery pressures (PAPs) would be found in SCD children and adolescents, especially those with a history of pulmonary complications: acute chest syndrome, obstructive sleep apnea, asthma, and reactive airway disease. Fifty-two SCD children, 23 of whom had underlying pulmonary disease, were screened for PHTN, which was defined as a tricuspid regurgitant jet velocity (TRV) of at least 2.5 m/s. Twenty-four (46.15%) SCD patients had increased PAP (i.e., TRV > or =2.5 m/s), and 6 (11.5%) had significant PHTN (i.e., TRV > or =3.0 m/s). Pulmonary disease was marginally associated with PHTN (odds ratio 2.80 and confidence interval 0.88 to 8.86; p = 0.0795). As in adult SCD patients with PHTN, this complication was correlated with the degree of hemolysis as manifested by significantly higher lactate dehydrogenase and bilirubin, lower hemoglobin and hematocrit levels, and a strong association with Hb-SS phenotype. However, after statistical adjustment for age and sex, increased serum LDH was not associated with the development of PHTN. Further studies are needed to clarify the prevalence and mechanisms of PHTN in pediatric and adolescent patients with SCD.

On the chemical synthesis and drug delivery response of folate receptor-activated, polyethylene glycol-functionalized magnetite nanoparticles

We describe here the chemical synthesis and in vitro drug delivery response of polyethylene glycol (PEG)-functionalized magnetite (Fe(3)O(4)) nanoparticles, which were activated with a stable ligand, folic acid, and conjugated with an anticancer drug, doxorubicin. The functionalization and conjugation steps in the chemical synthesis were confirmed using Fourier transform infrared spectroscopy. The drug-release behavior of PEG-functionalized and folic acid-doxorubicin-conjugated magnetic nanoparticles was characterized by two stages involving an initial rapid release, followed by a controlled release.

On the suitability of nanocrystalline ferrites as a magnetic carrier for drug delivery: functionalization, conjugation and drug release kinetics

Superparamagnetic nickel ferrite nanoparticles functionalized with polyvinyl alcohol, polyethylene oxide and polymethacrylic acid (PMAA) polymers and subsequently conjugated with doxorubicin anti-cancer drug are studied for their use as a magnetic carrier for drug delivery. Fourier transform infrared spectroscopy enabled examination of the ability of the nanoparticles to be functionalized with polymers and conjugated with doxorubicin drug. The functionalized polymer-coated nanocrystalline nickel ferrites retain the magnetic characteristics of non-functionalized nanocrystalline nickel ferrites (superparamagnetism, absence of hysteresis, remanence and coercivity at room temperature), encouraging their application as a magnetic carrier for drug delivery. The PMAA-coated nanoferrites are demonstrated as being a potentially superior magnetically targeted drug carrier based on FTIR results and drug release kinetics in the absence and presence of an external magnetic field.

Antimicrobial function of Nd3+-doped anatase titania-coated nickel ferrite composite nanoparticles: a biomaterial system

The present study describes and makes a relative comparison of the antimicrobial function of undoped and neodymium-doped titania coated-nickel ferrite composite nanoparticles processed by uniquely combining the reverse micelle and chemical hydrolysis approaches. This methodology facilitates the formation of undoped and doped photocatalytic titania shells and a magnetic ferrite core. The ferrite core is needed to help in the removal of particles from the sprayed surface using a small magnetic field. Doping of the titania shell with neodymium significantly enhances the photocatalytic and anti-microbial function of the core-shell composite nanoparticles without influencing the magnetic characteristics of the nickel ferrite core. The increased performance is believed to be related to the inhibition of electron-hole recombination and a decrease in the band gap energy of titania. The retention of magnetic strength ensures controlled movement of the composite nanoparticles by the magnetic field, facilitating their application as removable anti-microbial photocatalyst nanoparticles. The consistent behavior of the composite nanoparticles points to the viability of the synthesis process adopted.

Stability of Delta(9)-tetrahydrocannabinol (THC) in oral fluid using the Quantisal collection device

This article details the stability of Delta(9)-tetrahydrocannabinol (THC) in oral fluid during collection, extraction and storage. Oral fluid is being increasingly used as the specimen of choice for the detection of drug use in various applications. Studies to determine the extraction efficiency of THC from the collection buffer and stability under various laboratory storage conditions were carried out. THC was extracted from the collection pad and buffer with an average efficiency over 80% and was stable in Quantisal oral fluid extraction buffer when stored at refrigerated temperatures. Fluorescent lighting caused THC losses of over 50%, however the presence of the pad reduced the loss. In the dark, the loss of THC at room temperature was approximately 20% over 14 days. When stored with the serum separators in place, THC losses were significant. After 3 days, THC concentration was reduced by almost 30%, and after 14 days, 60% of the drug was lost and the losses were not concentration dependent.

Anti-microbial active composite nanoparticles with magnetic core and photocatalytic shell: TiO2-NiFe2O4 biomaterial system

Reverse micelle and chemical hydrolysis techniques have been successfully combined to synthesize composite nanoparticles consisting of a photocatalytic shell of titania and a magnetic core of nickel ferrite. The nature of titania shell, i.e. anatase or brookite, depends on the TiO2 and NiFe2O4 molar ratio. The work presented here describes the photocatalytic and anti-microbial activity of the composite nanoparticles together with the magnetic characteristics of the nickel ferrite core. The TiO2-coated NiFe2O4 nanoparticles retain the magnetic characteristics of uncoated nanocrystalline nickel ferrites (superparamagnetism; absence of hysteresis, remanence and coercivity at 300 K) encouraging their application as removable anti-microbial photocatalyst nanoparticles that can be extracted from the sprayed surface (human body or environment) after exposure.

Ketamine anaesthesia for paediatric ophthalmology surgery

AIMS

Children with treatable, vision impairing conditions may not have access to surgical care when they live in regions where anaesthesia is unavailable. The use of ketamine anaesthesia in a developing region was studied to determine its safety and effectiveness.

METHODS

This is a consecutive series of 679 children who had a variety of paediatric eye disorders necessitating a short general anaesthesia. Ketamine was administered intravenously by a paediatrician with training in paediatric resuscitation procedures. Both intraocular and extraocular procedures were performed. The location of treatment was the Tilganga Eye Hospital in Kathmandu, Nepal, a developing region of the world. The study took place over a 5 year period.

RESULTS

All procedures were performed without any anaesthetic complications. No child required unanticipated resuscitation or laryngeal intubation. Postoperative dysphoria occurred occasionally and was difficult to measure quantitatively. This side effect of ketamine resolved by the first postoperative day.

CONCLUSION

Ketamine is an effective agent for both intraocular and extraocular surgery in the paediatric age group. None of the children in this series needed resuscitation or intubations, and the ophthalmic surgery was carried out safely. Ketamine can be used safely in any ophthalmic procedure of short duration by a person having some training in anaesthetic resuscitation procedures. Because of its simplicity and safety, ketamine may be useful in a simple ophthalmic setup in the developing word.

Sero-prevalence and mother-to-infant transmission of hepatitis E virus among pregnant women in the United Arab Emirates

OBJECTIVES

(1) To study the prevalence of HEV infection in a cohort of pregnant women in the United Arab Emirates (UAE). (2) The rate of mother-to-infant transmission.

METHOD

Sera of 469 pregnant women residing in the UAE was tested for anti-HEV with ELISA and for HEV-RNA by polymerase chain reaction (PCR). Neonatal cord-blood and infant blood was similarly tested for anti-HEV and HEV-RNA. Out of these 469 women, 33% were UAE nationals (Group A) and Egyptians (Group B), respectively, and 34% were from the Indian sub-continent (Group C).

RESULTS

Out of 469 mothers 93 (20%) were anti-HEV positive and 28 (30%) of these 93 were HEV-RNA positive and symptomatic with on-going infection. The prevalence of anti-HEV was significantly increased amongst Groups B and C (Group A:B, P<0.001; Group A:C, P<0.001). Twelve of these 28 symptomatic women developed acute hepatic disease and two died undelivered, thus, were excluded from further study. Six of the remaining 10 women had non-fulminant acute viral hepatitis and four developed fulminant hepatic failure, of which one died in the early post-partum period. The remaining 16 women had mild symptomatic disease with complete recovery as did the remaining nine women with acute illness. Of the 10 babies born to mothers with acute disease, two were pre-term, three had anicteric hepatitis and two babies were born with hypothermia and hypoglycaemia and died within 48h. Noteworthy is the fact that, the 26 infants born to the 26 HEV-RNA positive mothers developed acute/on-going clinical infection and were HEV-RNA positive. Apart from the two early neonatal deaths, the remaining 24 infants had full recovery. No infant of the other mothers were symptomatic or had HEV-RNA. Thus, the mother-to-infant transmission was 100%. The remaining 65 sero-positive women remained asymptomatic with no evidence of clinical infection, continued to be HEV-RNA negative and delivered at term. Their infants had no evidence of infection and were sero-negative by 9 months of age, suggesting transplacental transmission of IgG antibodies.

CONCLUSIONS

There is a high prevalence of anti-HEV among pregnant women residing in the UAE. Twelve of infected women developed fulminant/acute hepatitis resulting in three fatalities. Evidence suggests significant vertical transmission of HEV among HEV-RNA positive mothers with appreciable perinatal morbidity and mortality. Excluding mothers with acute hepatic disease, Breast-feeding appears to be safe in HEV sero-positive mothers.

Plasma S-adenosylhomocysteine is a more sensitive indicator of cardiovascular disease than plasma homocysteine

BACKGROUND

Although plasma total homocysteine has been identified as an independent risk factor for vascular disease in a multitude of studies, there is a considerable overlap in values between patients at risk and control subjects. The difference in values can be used to distinguish statistically between the 2 groups, provided each group is large enough; however, discriminating between individual patients at risk and control subjects is difficult.

OBJECTIVE

We investigated whether the precursor of homocysteine, S-adenosylhomocysteine, is a more sensitive indicator of risk.

DESIGN

We measured plasma total homocysteine, S-adenosylhomocysteine, S-adenosylmethionine, creatinine, folate, and vitamin B-12 in 30 patients with proven cardiovascular disease and 29 age- and sex-matched control subjects.

RESULTS

The homocysteine values (+/-SD) were 12.8 +/- 4.9 (95% CI: 11.0, 14.7) micromol/L for patients and 11.0 +/- 3.2 (9.8, 12.2) micromol/L for control subjects. The S-adenosylhomocysteine values were 40.0 +/- 20.6 (32.3, 47.7) nmol/L for patients and 27.0 +/- 6.7 (24.5, 30.0) nmol/L for control subjects (P = 0.0021). The S-adenosylmethionine values were 121.8 +/- 42.9 (105.8, 137.8) nmol/L for patients and 103.9 +/- 21.8 (95.6, 112.2) nmol/L for control subjects (P = 0.0493). The creatinine values were 110 +/- 27 (97, 120) micromol/L for patients and 97 +/- 9 (80, 100) micromol/L for control subjects (P = 0.0025). Values for folate and vitamin B-12 did not differ significantly between groups.

CONCLUSIONS

Plasma S-adenosylhomocysteine appears to be a much more sensitive indicator of the difference between patients with cardiovascular disease and control subjects than is homocysteine. Both plasma total homocysteine and S-adenosylhomocysteine are significantly correlated with plasma creatinine in patients.

Prevalence of obstructive sleep apnea syndrome in a cohort of 1,207 children of southern Italy

STUDY OBJECTIVE

To determine the prevalence of sleep-related breathing disturbances in a large cohort of school-aged and preschool-aged children of Southern Italy.

DESIGN AND SETTING

This cross-sectional prevalence study was designed in two phases: a screening phase aimed to identify symptomatic children from a cohort of 1,207 by a self-administered questionnaire, and an instrumental phase for the definition of sleep-related disorders.

PATIENTS AND METHODS

One thousand two hundred seven children were screened by a self-administered questionnaire. There were 612 female children (51%) and 595 male children (mean age, 7.3 years; range, 3 to 11 years). According to answers, children were classified in three groups: nonsnorers, occasional snorers, and habitual snorers. All habitual snoring children underwent a polysomnographic home evaluation, and those with an oxygen desaturation index > 2 were considered for nocturnal polygraphic monitoring (NPM). Children with an apnea/hypopnea index > 3 received a diagnosis of obstructive sleep apnea syndrome (OSAS).

RESULTS

A total of 895 questionnaires (74.2%) were returned and scored; 710 children (79.3%) were identified as nonsnorers, 141 children (15.8%) were identified as occasional snorers, and 44 children (4.9%) were identified as habitual snorers. The percentage of male children who were habitual snorers was higher than the percentage of female children who were habitual snorers (6.1% vs 3.7%, respectively; p < 0.09). OSAS was diagnosed in nine children by NPM.

CONCLUSION

The lower limit of prevalence of OSAS in childhood is 1% (95% confidence interval [CI], 0.8 to 1.2). If we add the five children who underwent adenoidectomy and/or tonsillectomy because of worsening clinical condition and the two children who were shown to have evidence of OSAS on domiciliary oximetry, then the prevalence is 1.8% (higher limit of prevalence; 95% CI, 1.6 to 2.0).

Retroperitoneal endometriosis causing unilateral hip pain

BACKGROUND

The usual symptoms of endometriosis are secondary dysmenorrhea, dyspareunia, and infertility, but when located in the retroperitoneal space, it might have atypical symptoms that delay diagnosis and postpone therapy.

CASE

A young nulligravida presented with secondary dysmenorrhea and concurrent cyclic hip pain. Recent laparoscopy was reportedly normal. Computed tomography (CT)-directed percutaneous needle biopsy of a retroperitoneal mass showed endometriosis. Laparotomy with retroperitoneal dissection removed the endometriosis, and operative arthroscopy released strictured hip tendons improving her hip pain and limp.

CONCLUSION

Retroperitoneal endometriosis presenting as hip pain was diagnosed by CT-guided percutaneous needle biopsy permitting removal by a multidisciplinary surgical approach.

Influence of soybean trypsin inhibitor on small bowel enzyme activities during rotavirus infection in malnourished infant mice

Rotavirus (RV) is considered to be one of the major causes of acute episodic diarrhoea throughout the world. This study was undertaken to investigate the effect of soybean trypsin inhibitor (TI) on brush-border enzymes during rotavirus infection in protein energy malnourished (PEM) infant mice. Animals were divided into 4 groups, namely controls, PEM, PEM+RV and PEM+RV+TI (n = 36 each). Group 1 and 2 animals were orally inoculated with 50 microl of normal saline each. Group 3 animals were orally inoculated with 50 microl of 100 ID50 dose of RV stock each. Group 4 animals were similarly inoculated with 0.6 mg TI/g body weight along with 50 microl of RV stock each. Animals were examined daily for diarrhoea and their body weight was recorded on alternate days postinoculation (dpi). Animals were killed by cervical dislocation after being given light chloroform anesthesia on 0, 1, 3, 5, 7 and 10 dpi. Small intestines were excised and homogenized in normal saline. Proteins, gammaglutamyl transpeptidase, alkaline phosphatase and disaccharidases were estimated in jejunum and ileum. Body weight was significantly reduced in PEM animals and with RV infection. Histologically, focal areas of vacuolar degeneration of lining epithelium were seen in RV-infected animals. Disaccharidases and other enzyme activities were decreased significantly in the PEM group compared to healthy controls and further depressed with RV infection in malnourished animals as compared to non-infected PEM. The enzyme activities were restored in animals receiving TI along with RV compared to the group receiving RV without TI. With the administration of soybean TI, the activities of disaccharidases, alkaline phosphatase, gammaglutamyl transpeptidase and intestinal architecture were restored showing a protective effect in PEM during RV infection.

Protection against rotavirus diarrhoea in mice by trypsin inhibitor

To investigate the role of soyabean trypsin inhibitor (TI) during rotavirus (RV) diarrhoea, changes in enzyme activities of six relevant mucosal enzymes (lactase, sucrase, maltase, trehalase, glucoamylase and alkaline phosphatase) were assayed following inoculation of suckling mice with EB rotavirus (serotype 3) along with the TI and compared with the age-matched healthy control mice. The animals were divided into three groups i.e. group 1 (controls), group 2 (RV inoculated) and group 3 (RV + TI inoculated and sacrificed under light anaesthesia on 0, 1, 3, 5, 7 and 10 day post inoculation (dpi). Then intestines were excised and divided into two parts (jejunum and ileum). They were separately homogenized in 0.9% cold normal saline and activities of mucosal enzyme were measured. Alkaline phosphatase and disaccharidases were found to be decreased significantly in RV inoculated animals in both the anatomical portions of small intestine of mice. These enzyme levels were restored with the administration of TI i.e. in group 3 and became comparable to the controls in both intestinal portions. These studies suggest that activity of intestinal enzymes which are important in digestive absorptive functions of small intestine were restored with the addition of TI whengiven to infant mice showing its protective efficacy during rotavirus infection.

Effect of rotavirus infection on lipid composition and glucose uptake in infant mouse intestine

OBJECTIVE

To study the effect of rotavirus infection on lipid composition and glucose uptake in small intestine of infant mice.

METHODS

Thirty six 7-day old balb/c mice were given 50 mL (100 ID50) rotavirus suspension orally; 36 control animals received only normal saline. Body weight of animals was recorded. Six animals in each group were sacrificed on days 0, 1, 3, 5, 7 and 10 post-inoculation (pi). Intestines were removed, everted and homogenized in ice-cold saline. Cholesterol and phospholipid content, glucose uptake and alkaline phosphatase in the jejunum and ileum were determined.

RESULTS

Rotavirus infection led to a significant decrease in body weight with on days 3 and 5 pi as compared to controls, and to an increase in cholesterol and phospholipid content of the intestine. Uptake of glucose also increased significantly. Alkaline phosphatase activity was significantly reduced on days 3 and 5 pi as compared to controls.

CONCLUSION

This study provides characterization of the lipid composition and uptake of glucose in infant mice small intestinal segments during rotavirus infection.

Influence of resin cross-linking on solid-phase chemistry

A range of PS-DVB resins were prepared by suspension polymerization with styrene, p-chloromethyl styrene, and DVB. Yields of polymerization increased (from 40% to almost 80%) with increasing cross-linking. The beads exhibited the expected swelling characteristics, with the 0.3% resin swelling to almost 9 times its dry volume in CHCl3. Kinetics of cleavage of the dye Methyl Red from the range of Rink linked resins showed rate enhancements of up to 500% between the 6.0 and the 0.3% cross-linked resins. Total synthesis of Kawaguchipeptin B was carried out on the resins, and their performance during the syntheses was investigated. Contrary to expectations, the purities of the cyclic peptide product increased with increasing resin cross-linking doubling from the 0.3-6.0% resin. A Suzuki reaction showed the half-lives of reaction increased with increasing resin cross-linking with an 11-fold increase in half-life between the 0.3-2.7% resin. Surprisingly, we observed very little reaction in the case of the 3.0 and 6.0% cross-linked resins.

Synergistic interaction of adrenaline and histamine in human platelet aggregation is mediated through activation of phospholipase, map kinase and cyclo-oxygenase pathways

This study was conducted to examine the mechanism(s) of synergistic interaction of histamine- and adrenaline-mediated human platelet aggregation. We found that platelet aggregation mediated by subthreshold concentrations of histamine (1-4 microm) plus adrenaline (0.5-2 microm) is inhibited by both an alpha(2)-adrenoceptor blocker (yohimbine) and a histamine (H1) receptor antagonist (diphenhydramine). In examining the role of the downstream signalling pathway, we found that such an interaction is inhibited by the calcium channel blockers verapamil and diltiazem. However, platelet aggregation by adrenaline plus histamine was inhibited by very low concentrations of the phospholipase C (PLC) inhibitor, U73122 (IC(50)= 1.2 microm), the MEK inhibitor, PD98059 (IC(50)= 1.1 microm) and the cyclo-oxygenase (COX) inhibitor, indomethacin (IC(50)= 7 microm). However the inhibition of receptor tyrosine kinase, protein kinase C and phosphatidylinositol 3-kinase by genistien, chelerythrine and wortmannin, respectively, had no significant effect on aggregation. Similarly the nitric oxide donor (SNAP) had no effect on this synergism. These data suggest that the synergistic effect of histamine and adrenaline during human platelet aggregation is receptor mediated and involves activation of PLC, COX and MAP kinase signalling pathways.

Combination nucleoside analog reverse transcriptase inhibitor(s) plus nevirapine, nelfinavir, or ritonavir in stable antiretroviral therapy-experienced HIV-infected children: week 24 results of a randomized controlled trial--PACTG 377. Pediatric AIDS Clinical Trials Group 377 Study Team

One hundred eighty-one antiretroviral-experienced, protease inhibitor-naive, clinically stable HIV-infected children between 4 months and 17 years of age were randomly assigned to receive one of four combination regimens to evaluate the change in plasma HIV RNA, safety, and tolerance when changing antiretroviral therapy to a protease inhibitor-containing combination regimen. All four regimens contained stavudine; in addition children received nevirapine plus ritonavir, lamivudine plus nelfinavir, nevirapine plus nelfinavir, or lamivudine plus nevirapine plus nelfinavir. Twelve additional children chose to receive stavudine plus lamivudine plus nelfinavir, with nelfinavir given bid, rather than tid as for the main regimens. Overall, 51% (89/176; 95% CI 43-58%) of the children on the randomized portion of the study had an HIV RNA response (< or =400 copies/ml) on at least two of the three HIV RNA determinations taken at Weeks 8, 12, and 16. At Week 24 the proportion of children with an HIV RNA response still on initial therapy was 47% (83/176; 95% CI 40-55%) and ranged from 41 to 61% for the four randomized treatment arms. Rash was frequently seen (27%) on the treatment arms containing nevirapine. At Week 24 64% (7/11, 95% CI 31-89%) of the children on the bid nelfinavir combination regimen were still on initial therapy with an HIV RNA response as compared with 46% (23/50; 95% CI 32-61%) on the corresponding tid nelfinavir combination regimen. A change in antiretroviral therapy to a protease inhibitor-containing regimen was associated with a virological response rate of approximately 50% for this patient population.

Intestinal pseudo-obstruction due to neurofibromatosis responding to cisapride

Gastrointestinal involvement in neurofibromatosis presenting with mechanical obstruction, hemorrhage or intussusception is known. Small bowel dysmotility and intestinal pseudo-obstruction due to neurofibromatosis is rare. A 23-year-old man with classical neurofibromatosis presented with intermittent episodes of intestinal pseudo-obstruction, small bowel bacterial overgrowth and steatorrhea. The patient had good symptomatic improvement with cisapride.

Synergistic activation of yeast-expressed rat androgen receptor by modulators of protein kinase-A

We have employed a yeast (Saccharomyces cerevisiae) based rat androgen receptor expression system to examine the cross-talk between different signalling pathways. We report here the synergistic modulation of androgen regulated transcriptional activation of beta-galactosidase reporter activity by the activators of protein kinase-A, like forskolin and 8-bromo-cyclic AMP. A similar ligand-dependent enhancement of reporter activity compared to a DHT treated control has been noticed with okadaic acid, which is a potent inhibitor of protein phosphatase. The activation could be blocked by protein kinase-A/C inhibitor, H7. Forskolin treatment neither altered levels of receptor mRNA nor [3H]R1881 binding to the receptor. Although it promotes binding of receptor to an androgen response element, forskolin was unable to activate subsequent interaction with the transcription machinery in the absence of androgen. Additionally, the synergistic actions of these activators were independent of the degree of androgen response element occupancy. Anti-androgens, cyproterone acetate and flutamide, which failed to exhibit antagonistic behaviour with yeast expressed receptor, were able to antagonize only the forskolin mediated augmentation of reporter activity. Finally, analyses of mutants established the role of DNA and steroid binding domains of receptor for this synergism.

Influence of the CCR2-V64I polymorphism on human immunodeficiency virus type 1 coreceptor activity and on chemokine receptor function of CCR2b, CCR3, CCR5, and CXCR4

The chemokine receptors CCR5 and CXCR4 are used by human immunodeficiency virus type 1 (HIV-1) in conjunction with CD4 to infect cells. In addition, some virus strains can use alternative chemokine receptors, including CCR2b and CCR3, for infection. A polymorphism in CCR2 (CCR2-V64I) is associated with a 2- to 4-year delay in the progression to AIDS. To investigate the mechanism of this protective effect, we studied the expression of CCR2b and CCR2b-V64I, their chemokine and HIV-1 coreceptor activities, and their effects on the expression and receptor activities of the major HIV-1 coreceptors. CCR2b and CCR2b-V64I were expressed at similar levels, and neither molecule affected the expression or coreceptor activity of CCR3, CCR5, or CXCR4 in cotransfected cell lines. Peripheral blood mononuclear cells (PBMCs) from CCR2-V64I heterozygotes had normal levels of CCR2b and CCR5 but slightly reduced levels of CXCR4. CCR2b and CCR2b-V64I functioned equally well as HIV-1 coreceptors, and CCR2-V64I PBMCs were permissive for HIV-1 infection regardless of viral tropism. The MCP-1-induced calcium mobilization mediated by CCR2b signaling was unaffected by the polymorphism, but MCP-1 signaling mediated by either CCR2b- or CCR2-V64I-encoded receptors resulted in heterologous desensitization (i.e., limiting the signal response of other receptors) of both CCR5 and CXCR4. The heterologous desensitization of CCR5 and CXCR4 signaling by both CCR2 allele receptor types provides a mechanistic link that might help explain the in vivo effects of CCR2 gene variants on progression to AIDS as well as the reported antiviral activity of natural CCR2 ligands.

HIV prevention among injecting drug users: responses in developing and transitional countries

OBJECTIVE

Human immunodeficiency virus (HIV) infection associated with injecting drug use has been reported in at least 98 countries and territories worldwide. There is evidence that new epidemics are emerging in different regions, including Eastern Europe, Latin American, and the eastern Mediterranean. The authors provide a global overview of the situation of HIV infection associated with injecting drug use and responses that have been implemented in various developing and transitional countries.

METHODS

Although there has been extensive documentation of the extent and nature of of HIV infection associated with injecting drug use in many developed countries and the various interventions implemented in those countries, there is very limited information on the situation in developing and transitional countries. This chapter brings together information from a broad range of sources, including published literature; "gray" or "fugitive" literature; data collected by the World Health Organization (WHO), the Joint United Nations Programme on HIV/AIDS (UNAIDS) and the United Nations International Drug Control Programme (UNDCP); personal communications; and direct observation by the authors. The authors have traveled extensively to a wide range of developing and transitional countries and have accessed information not readily available to the international research community.

RESULTS

A wide range of HIV prevention strategies targeting injecting drug users (IDUs) has been implemented in developing countries and countries in transition. Interventions include opioid substitution pharmacotherapy, needle syringe exchange and distribution, condom and bleach distribution, outreach to IDUs, peer education programs, and social network interventions. In some communities, completely new models of intervention and service delivery have developed in response to specific local needs and limitations.

CONCLUSIONS

Although empirical data may currently be lacking to demonstrate the effectiveness of may HIV prevention programs targeting IDUs in developing and transitional countries, there is evidence that innovative HIV prevention initiatives are being implemented and sustained in a wide range of sociocultural settings.

Activation of rat androgen receptor by androgenic ligands is unaffected by antiandrogens in Saccharomyces cerevisiae

The E. coli lacZ has been utilized as a reporter to evaluate ligand-mediated activation of the rat androgen receptor (AR) in Saccharomyces cerevisiae strain YCR1. beta-galactosidase activity was androgen-specific and was found to be inducible approximately 260-fold by dihydrotestosterone (DHT), testosterone and R1881. None of the antiandrogens tested was able to antagonize the DHT-dependent induction of beta-galactosidase activity. In the gel retardation assay, exposure of the receptor to DHT in vitro led to the formation of a protein-DNA complex that was not detected in yeast extracts unexposed to hormone. However, activation of AR by a steroidal (cyproterone acetate) and a non-steroidal antiandrogen (flutamide) either alone or in combination with DHT also results in a similar migration pattern. Additionally, LEM1, the ABC transporter that selectively modulates the biological potency of steroids in yeast, although operative in YCR1, was not responsible for antiandrogen resistance. These results thus indicate the involvement of other non-receptor factor(s) in mediating the effect of antiandrogens in yeast.

CXCR-4 is expressed by primary macrophages and supports CCR5-independent infection by dual-tropic but not T-tropic isolates of human immunodeficiency virus type 1

Primary macrophages are infected by macrophage (M)-tropic but not T-cell line (T)-tropic human immunodeficiency virus type 1 (HIV-1) strains, and CCR5 and CXCR-4 are the principal cofactors utilized for CD4-mediated entry by M-tropic and T-tropic isolates, respectively. Macrophages from individuals homozygous for an inactivating mutation of CCR5 are resistant to prototype M-tropic strains that depend on CCR5 but are permissive for a dual-tropic isolate, 89.6, that can use both CCR5 and CXCR-4, as well as CCR2b, CCR3, and CCR8. Here we show that 89.6 entry into CCR5-deficient macrophages is blocked by an anti-CXCR-4 antibody and by the CXCR-4-specific chemokine SDF but not by the ligands to CCR2b or CCR3. Reverse transcription-PCR demonstrated expression of CXCR-4 but not CCR3 or CCR8 in macrophages, while CCR2b was variable. Macrophage surface expression of CXCR-4 was confirmed by immunofluorescence staining and flow cytometry. Thus, CXCR-4 is expressed by primary macrophages and functions as a cofactor for entry by dual-tropic but not T-tropic HIV-1 isolates, and macrophage resistance to T-tropic strains does not result from a lack of the T-tropic entry cofactor CXCR-4. Since CXCR-4 on macrophages can be used by some but not other isolates, these results indicate that HIV-1 strains differ in how they utilize chemokine receptors as cofactors for entry and that the ability of a chemokine receptor to mediate HIV-1 entry differs, depending on the cell type in which it is expressed.

Classical light scattering quantitation of protein aggregates: off-line spectroscopy versus HPLC detection

This paper describes the development and validation of a new off-line approach to quantitate both covalent and noncovalent, in-solution aggregates present in protein formulations and compares the new assay to established HPLC methods. This off-line analysis is well suited for use in QC release testing, formulation development and stability indicating applications. An inexpensive, continuous source HPLC fluorometer has been adapted with the addition of second order filters for use as a sensitive right-angle scatterometer which can determine the molecular weight of protein aggregates in solution. When used as an HPLC detector, right-angle light scattering is a sensitive method which can determine the molecular weight of peaks separable by HPLC, thus discriminating between monomers of different conformations and aggregates. The weight-averaged molecular weight of aggregate peaks can be calculated with system calibration, yielding the average number of monomers per aggregate. If the protein concentration is high enough for an adequate signal, the off-line technique of right-angle light scattering of protein formulations has advantages of convenience and speed over the HPLC approach. Samples are placed in standard fluorometer cuvettes and toluene is used as a calibrator. Data are presented which show the off-line (static) method to be extremely rapid, rugged and precise. The accuracy of this approach is demonstrated through cross-validation to traditional GPC analysis of protein aggregate distributions. This non-invasive light scattering approach is particularly useful when non-covalent protein aggregation is reversible and readily altered by chromatographic separations typically used for characterizing aggregates.

Discontinuation of long-term transfusion therapy in patients with sickle cell disease and stroke

Long-term transfusion therapy in patients with sickle cell disease and stroke markedly decreases the risk of stroke recurrence. However, it is not known how long the transfusions should be continued. Published reports have documented a high risk of stroke recurrence after stopping transfusion. We report on nine consecutive patients with sickle cell disease and stroke whose long-term transfusion therapy was discontinued and in whom no ischemic strokes developed during 80.75 patient years of follow-up.

Homocysteine in sickle cell disease: relationship to stroke

PURPOSE

The risk factors and pathophysiology of stroke and other serious complications of sickle cell disease (SCD) are poorly defined. Hyperhomocysteinemia has recently been identified as a risk factor for stroke and other vascular diseases in the general population, however its role in SCD has not been investigated.

PATIENTS AND METHODS

We measured serum homocysteine and red cell folate levels in 100 patients with SCD, including 16 patients with stroke. A disease severity score was determined for all patients and those without stroke were classified into mild (44 patients) or severe (40 patients) disease groups.

RESULTS

Homocysteine levels for the stroke group (median 13.3 mumol/L, mean 13.1 +/- 4.3 mumol/L) were significantly higher than those in patients without stroke (median 9.7 mumol/L, mean 10.7 mumol/L) (P < 0.02), and on multiple regression analysis homocysteine level was independently correlated with stroke (P < 0.026). Homocysteine and folate levels were inversely correlated (r = -0.41, P < 0.00005). Using logistic regression, the odds ratio for stroke in patients with homocysteine levels above the median (10.1 mumol/L) was 3.5 in this group of patients (95% confidence interval 1.1 to 11.9).

CONCLUSION

High homocysteine levels may be a risk factor for development of stroke in SCD patients. The role of homocysteine in the pathogenesis of stroke in SCD needs to be examined in a longitudinal, prospective study.

Study of oxidative-stress in rifampicin-induced hepatic injury in growing rats with and without protein-energy malnutrition

1. Rifampicin (RMP) induced hepatic injury was investigated in growing rats. The interaction of moderate and severe protein-energy malnutrition (PEM) was also investigated. 2. Status of oxidative/antioxidative profile was studied by the mechanistic approach, to enumerate the nature of injury. 3. Successful hepatic injury in rats was produced by giving intraperitoneal injection of RMP (50 mg/kg/day). 4. Hepatic lipid peroxidation was significantly increased in all the RMP treated rats. 5. Superoxide dismutase, catalase and glutathione peroxidase activities in the hepatic tissue decreased with RMP treatment. 6. Hepatic thiols represented as total and protein-bound thiols, showed significant elevation, whereas the non protein thiols remain unchanged with RMP treatment. 7. Glutathione-S-transferases also showed significant elevation against 1,2-dichloro-4 nitrobenzene (DCNB) and ethacrynic acid (EA) as substrates. 8. The oxidative/antioxidative profile was observed to be more severely affected with coexistence of malnutrition. 9. Histopathological correlation showed an additional fatty infiltration of hepatocytes with coexistence of malnutrition. 10. Thus, in conclusion, it can be speculated that an altered oxidative/antioxidative profile is the closely associated with production of RMP induced hepatic injury.

Role of CCR5 in infection of primary macrophages and lymphocytes by macrophage-tropic strains of human immunodeficiency virus: resistance to patient-derived and prototype isolates resulting from the delta ccr5 mutation

The alpha-chemokine receptor fusin (CXCR-4) and beta-chemokine receptor CCR5 serve as entry cofactors for T-cell (T)-tropic and macrophage (M)-tropic human immunodeficiency virus type 1 (HIV-1) strains, respectively, when expressed with CD4 in otherwise nonpermissive cells. Some M-tropic and dual-tropic strains can also utilize other beta-chemokine receptors, such as CCR2b and CCR3. A mutation of CCR5 (delta ccr5) was recently found to be common in certain populations and appears to confer protection against HIV-1 in vivo. Here, we show that this mutation results in a protein that is expressed intracellularly but not on the cell surface. Primary CD4 T cells from delta ccr5 homozygous individuals were highly resistant to infection with prototype M-tropic HIV-1 strains, including an isolate (YU-2) that uses CCR5 and CCR3, but were permissive for both a T-tropic strain (3B) and a dual-tropic variant (89.6) that uses CXCR-4, CCR5, CCR3, or CCR2b. These cells were also resistant to M-tropic patient isolates but were readily infected by T-tropic patient isolates. Primary macrophages from delta ccr5 homozygous individuals were also resistant to infection with M-tropic strains, including YU-2, but the dual-tropic strain 89.6 was able to replicate in them even though macrophages are highly resistant to CXCR-4-dependent T-tropic isolates. These data show that CCR5 is the essential cofactor for infection of both primary macrophages and T lymphocytes by most M-tropic strains of HIV-1. They also suggest that CCR3 does not function for HIV-1 entry in primary lymphocytes or macrophages, but that a molecule(s) other than CCR5 can support entry into macrophages by certain virus isolates. These studies further define the cellular basis for the resistance to HIV-1 infection of individuals lacking functional CCR5.

Thyroid dysfunction in HIV-infected children: is L-thyroxine therapy beneficial?

PURPOSE

To assess thyroid function in symptomatic HIV-infected infants and children with failure to thrive and to evaluate clinical response in patients with hyperthyrotropinemia to levothyroxine.

METHODS

We evaluated 11 children (mean age: 1.5 years; males = 5, females = 6) with HIV infection and failure to thrive (weight and height > 2 SD below the mean) for presence of hypothyroidism. Thyroid-stimulating hormone (TSH) and thyroxine (T4) were measured. Four children with high basal TSH and one child with a normal basal TSH underwent the Thyrotropin-releasing hormone (TRH) stimulation test as well. Four children received treatment with L-thyroxine.

RESULTS

Eight of the 11 children had high basal TSH levels. All patients had normal or increased T4 values. The TRH stimulation test showed an exaggerated response in all four patients with high basal TSH values and a normal response in one patient with normal basal THS values. All four patients who received treatment with L-thyroxine showed normalization of the TSH. Increased growth velocity was noted in 3 of 4 patients. The fourth patient died within two weeks following initiation of therapy for overwhelming candida sepsis. The autopsy of this patient showed atrophy of the thyroid gland. Two of the four patients with high TSH levels, who did not receive L-thyroxine, died; the other two did not show any improvement in their height z scores. Two patients with a high TSH also had high thyroid-binding hormone (TBG) levels. Both patients with the high TBG died within 2 to 3 months of the study.

CONCLUSIONS

Hypothyroidism as indicated by elevated basal TSH and abnormal TRH response was common in the HIV-infected children in this study and may have contributed to failure of growth in these children. Replacement therapy resulted in correction of abnormal TSH and improvement of height z scores during the period of observation. The significance of these findings needs to be confirmed in a larger prospective study.

Protein-energy malnutrition and oxidative injury in growing rats

1. Weaning rats were fed ad libitum isocaloric diets containing 5% and 20% casein based proteins. 5% protein diet was protein deficient diet. Pair fed rats with the 5% protein group were maintained simultaneously on 20% protein diet but the amount restricted to the amount taken up by PEM group. 2. Glutathione, antioxidative enzymes, lipid peroxidation and histopathological studies in liver and only glutathione and antioxidative enzymes in blood were carried out. 3. Rats fed the 5% protein diet developed a severe protein energy malnutrition (PEM) whereas those on pair-fed diet developed mild to moderate PEM. 4. Glutathione related thiols superoxide dismutase, glutathione peroxidase, catalase and glutathione-Stransferase with (1 Chloro 2,4-dinitro benzene (CDNB) substrate) were decreased in liver with concomitant increase of lipid peroxidation in severe PEM. In blood glutathione, glutathione peroxidase and catalase were decreased while superoxide dismutase was increased in severe PEM group. 5. Mild to moderate PEM (pair-fed group) also resulted in similar changes in liver except glutathione peroxidase, lipid peroxidation in liver and superoxide dismutase in blood. 6. Hepatic injury was detectable only in the severe PEM group. 7. Oxidative-stress and hepatic injury occurred in severe PEM and to a lesser degree in mild to moderate PEM.