Apoptosis cascade proteins are regulated in vivo by high intracolonic butyrate concentration: correlation with colon cancer inhibition

The present study was aimed at evaluating the effect of high intracolonic butyrate concentrations, either through fermentation of a soluble fiber-enriched diet or via intracolonic butyrate instillation, on colon cancer in a chemically induced (dimethylhydrazine) rat model. The effects were tested in four groups of dimethylhydrazine-treated rats: (i) rats fed a standard diet, (ii) rats fed a diet enriched with 15% citrus pectin, a soluble fiber that ferments and produces a high concentration of intracolonic butyrate, (iii) rats fed a standard diet and intrarectally instilled with a sodium butyrate solution (50 mM), (iv) rats fed a standard diet and intrarectally instilled with sodium butyrate vehicle solution (100 mM NaCl). The apoptotic index in the distal colon of rats fed pectin was higher than in colonic tissue from rats fed a standard diet. The expression of caspase-1, a cysteine protease implicated in the regulation of programmed cell death, as detected by both Northern and Western analysis, showed the highest mRNA and protein levels in colonic tissue from rats intrarectally instilled with butyrate. Immunohistology confirmed the Western blot findings. Expression of the cleaved poly(ADP-ribose) polymerase product, a downstream nuclear substrate for caspase-3 in the apoptotic pathway, was elevated in both the pectin-fed and butyrate-instilled groups. Expression of the antiapoptotic protein Bcl-2 was significantly reduced following pectin feeding as well as butyrate instillation. The highest expression of Bcl-2 was observed in tumor tissue. A marked reduction in aberrant crypt number was observed in colonic tissue obtained from both the pectin-fed and butyrate-instilled groups relative to rats from the standard diet group. The average tumor volume per rat in both the pectin-fed and butyrate-instilled groups was significantly lower than in rats from the standard diet and the sodium butyrate vehicle-instilled groups. We conclude that high butyrate levels, either instilled or obtained following fermentation of soluble dietary fibers, inhibit early and late events in colon tumorigenesis by controlling the transcription expression and activity of key proteins involved in the apoptotic cascade.

The role of copper in topa quinone biogenesis and catalysis, as probed by azide inhibition of a copper amine oxidase from yeast

All known copper amine oxidases (CAOs) contain 2,4,5-trihydroxyphenylalanine quinone (TPQ) as a redox cofactor. TPQ is derived posttranslationally from a specific tyrosine residue within the protein itself, and is utilized by the enzyme to oxidize amines to aldehydes. Several oxidative mechanisms for both turnover and the biogenesis of the cofactor have been proposed in recent years, which differ mainly in the nature of the interaction of oxygen with the enzyme. In this study, azide is used to probe the role of copper in catalysis and biogenesis, especially with respect to potential interactions between the metal and oxygen. During turnover, it is found that azide is a noncompetitive inhibitor with respect to O(2), most consistent mechanistically with oxygen binding off the metal prior to reaction. During biogenesis, it is found that azide likely prohibits ligation of the precursor tyrosine to the copper, thus preventing the formation of this key intermediate. This result is consistent with previous proposals, where the copper-tyrosine unit is the species that undergoes reaction with O(2). In addition, it is found that oxygen consumption is kinetically uncoupled from TPQ formation; this leads to an expanded kinetic model for biogenesis, with important implications for previous results.

Evaluation of a medium (STGG) for transport and optimal recovery of Streptococcus pneumoniae from nasopharyngeal secretions collected during field studies

Field studies of Streptococcus pneumoniae (pneumococci) nasopharyngeal (NP) colonization are hampered by the need to directly plate specimens in order to ensure isolate viability. A medium containing skim milk, tryptone, glucose, and glycerin (STGG) has been used to transport and store NP material, but its ability to preserve pneumococci has not been evaluated. Our objective was to qualitatively and semiquantitatively evaluate the ability of STGG to preserve pneumococci in NP secretions. Entwined duplicate calcium alginate NP swab samples were obtained from children. One swab was plated directly onto a gentamicin blood agar plate; the other was placed in STGG. Growth from the directly plated specimen was compared with growth from an STGG aliquot immediately cultured or stored at -70 degrees C for 9 weeks, -20 degrees C for 9 weeks, or 4 degrees C for 5 days. Of 186 specimens, 96 (52%) were positive for pneumococci from the direct plating; 94 (98%) of these were positive from the fresh STGG specimen. Pneumococci were recovered from all 38 positive specimens frozen at -70 degrees C, all 18 positive specimens frozen at -20 degrees C, and 18 of 20 positive specimens stored at 4 degrees C. Recovery of pneumococci after storage of NP material in STGG medium at -70 degrees C is at least as good as that from direct plating. Storage at -20 degrees C is also acceptable. Storage at 4 degrees C for 5 days is not ideal.

Electrospray ionization mass spectrometry analysis of lysophospholipids in human ascitic fluids: comparison of the lysophospholipid contents in malignant vs nonmalignant ascitic fluids

Lysophospholipids (lyso-PLs), including various glycerol-based and sphingosine-based lysophospholipids, play important roles in many biochemical, physiological, and pathological processes. The classical methods to analyze these lipids involve gas chromatography and/or high-performance liquid chromatography, which are time-consuming, cumbersome, and sometimes inaccurate due to the incomplete separation of closely related lipid species. We now describe the quantitative analysis of lyso-PLs in ascites samples from patients with ovarian cancer using electrospray ionization spectrometry. Three new classes of lyso-PL molecules are detected: alkyl-LPA, alkenyl-LPA, and methylated lysophosphatidylethanolamine. Importantly, the following lysophospholipid species are significantly increased in ascites from patients with ovarian cancer, compared to patients with nonmalignant diseases (e.g., liver failure): LPA (including acyl-, alkyl-, and alkenyl-LPA species), lysophosphatidylinositol, and sphingosylphosphorylcholine. Lysophosphorylcholine contents are also significantly different among ascitic fluids from the two groups of patients. However, the total phosphate content in ascites samples from patients with ovarian cancer is not significantly different compared to that from patients with nonmalignant disease.

Apoptosis (programmed cell death) in colonic cells: from normal to transformed stage

We determined apoptosis in whole rat colonic tissue and in isolated colonocytes from the various rat crypt regions in preneoplastic stages up to frank neoplasia following administration of the procarcinogen, dimethylhydrazine (DMH). Apoptotic cells were determined by the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL)-method, by evaluating sections stained with hematoxylin and eosin, and caspase-1 immunostaining. Apoptotic cells in whole colonic tissue from untreated rats were confined to the upper crypt while, in DMH-treated rats apoptotic and caspase-1 positive cells were located in the crypt proliferative regions. Numerous apoptotic and caspase-1-positive cells were found in sections from early tumors while in the delayed tumors, apoptotic-positive cells were absent and number of caspase-1-positive cells was negligible. A marked reduction in the apoptotic index along the crypt was observed in isolated transformed colonic cells, this was not the case for caspase-1-positive cells. We conclude that: (i) in colorectal tumors at progressive stage apoptosis is altered, (ii) the mechanistic alteration in apoptosis may be located between caspase-1-protease activity and the fragmentation process of DNA.

Enhanced ocular hypotensive response to timolol in rabbits with prior dexamethasone treatment

The purpose of this study was to determine glucocorticoid modulation of ocular pressure to timolol applied topically to rabbit eyes that were pretreated with dexamethasone. Rabbits were pretreated with five applications of topical 0.007% of dexamethasone (0.01% dexamethasone phosphate) or saline drops, administered at ten min intervals. The eyes were then treated with timolol maleate drops at concentrations of free base of 0.00007%, 0.0007%, 0.007% and 0.07%. An additional group of rabbits received dexamethasone pre-treatment only. Intraocular pressure was measured for the next four hr. Enhanced lowering of intraocular pressure was observed with dexamethasone pretreatment. Rabbits receiving the smaller dose of timolol had the least decrease in pressure. The most significant decreases in pressures occurred at 45 min after the administration of timolol with an average difference of 4.8 mm Hg between the timolol- and dexamethasone/timolol-treated eyes for the three largest concentrations of timolol. This synergism between glucocorticoids and beta-adrenergic blockers in lowering IOP may be potentially useful in the therapy of ocular hypertension and glaucoma.

The effect of a community intervention trial on parental knowledge and awareness of antibiotic resistance and appropriate antibiotic use in children

BACKGROUND

Overuse of antibiotics for children's upper respiratory infections is widespread and contributes to the emergence of antibiotic-resistant bacteria.

OBJECTIVE

To assess changes in knowledge and awareness regarding antibiotic resistance and appropriate antibiotic use after community-wide educational interventions to reduce inappropriate antibiotic use.

DESIGN

Baseline survey conducted during June through July 1997 and postintervention survey of baseline participants during June through August 1998.

SETTING

Communities in northern Wisconsin.

PARTICIPANTS

Parents of 729 randomly selected children <4 years of age were called until 215 in each of the intervention and control areas were reached. Of the 430 baseline participants, 365 (85%) participated in the postintervention survey.

INTERVENTION

Parent-oriented activities included distribution of materials and presentations. Physician-oriented activities included formal presentations and small group meetings.

OUTCOME MEASURE

Change in awareness about antibiotic resistance and knowledge about antibiotic indications.

RESULTS

A higher proportion of parents in the intervention area (53%) were exposed to 2 or more local educational messages, compared with the control area (23%). From the baseline to the postintervention survey, the percentage of parents with a high degree of antibiotic resistance awareness increased more in the intervention area (58% to 73%) than in the control area (60% to 65%). In the intervention area, there was also a larger increase in knowledge regarding appropriate indications for antibiotic use, compared with the control area. The proportion of parents who expected an antibiotic for their child and did not receive one declined in the intervention area (14% to 9%), while it increased in the control area (7% to 10%). In addition, the percentage of parents in the intervention area who brought their child to another physician because they did not receive an antibiotic decreased (5% to 2%), while it increased in the control area (2% to 4%).

CONCLUSION

Parental knowledge and awareness about antibiotic indications and antibiotic resistance can be changed with educational interventions directed at parents and clinicians.

Diagnosis and management of febrile children using the WHO/UNICEF guidelines for IMCI in Dhaka, Bangladesh

OBJECTIVE

To determine whether the fever module in the WHO/UNICEF guidelines for the integrated management of childhood illness (IMCI) identifies children with bacterial infections in an area of low malaria prevalence.

METHODS

Physicians assessed a systematic sample of 669 sick children aged 2-59 months who presented to the outpatient department of Dhaka Shishu Hospital, Bangladesh.

FINDINGS

Had IMCI guidelines been used to evaluate the children, 78% of those with bacterial infections would have received antibiotics: the majority of children with meningitis (100%), pneumonia (95%), otitis media (95%) and urinary tract infection (83%); and 50% or less of children with bacteraemia (50%), dysentery (48%), and skin infections (30%). The current fever module identified only one additional case of meningitis. Children with bacteraemia were more likely to be febrile, feel hot, and have a history of fever than those with dysentery and skin infections. Fever combined with parental perception of fast breathing provided a more sensitive fever module for the detection of bacteraemia than the current IMCI module.

CONCLUSIONS

In an area of low malaria prevalence, the IMCI guidelines provide antibiotics to the majority of children with bacterial infections, but improvements in the fever module are possible.

Pectin-enriched diet affects distribution and expression of apoptosis-cascade proteins in colonic crypts of dimethylhydrazine-treated rats

The colonic crypt contains highly proliferative cells in its base and differentiated cells on its luminal surface. Carcinogenesis significantly affects this orderly cellular distribution. The aims of this study were: i) to examine the expression of apoptosis-related proteins along the crypt-lumen axis during 1, 2-dimethylhydrazine (DMH)-induced carcinogenesis, ii) to assess whether a diet supplemented with the soluble fiber pectin affects those parameters, in comparison to non-carcinogen-treated rats and in relation to rats fed a standard diet and treated with DMH. The pectin-enriched diet induced upregulation of active caspase-1 subunit (20 kDa) and of caspase-3 precursor in DMH-treated rats. Pectin enhanced caspase-3 activity in all colonocyte populations, in both non-DMH and DMH-treated rats. The luminal colonocytes exhibited higher caspase-3 activity than proliferative colonocytes of rats fed a standard diet in non-DMH and DMH-treated rats, whereas in pectin-fed non-DMH-treated rats, equal activity was measured among all colonocyte populations. In the DMH-treated rats, the cleaved poly(ADP-ribose) polymerase subunit (89 kDa) was detected in luminal colonocytes of rats fed pectin and was higher than in rats fed the standard diet. Bak was equally expressed in isolated colonocytes from rats of both dietary groups treated with DMH and in the normal rats fed pectin, whereas in the non-DMH-treated rats fed a standard diet, higher expression was obtained in differentiated colonocytes. In the DMH-treated rats, Bcl-2 expression was lower in all colonocytes harvested from rats fed pectin, relative to rats fed the standard diet. Apoptotic index in the DMH-treated groups was higher in rats receiving the pectin diet compared with the standard diet in both the differentiated cell populations and the proliferating colonocytes. Average tumor number and volume per rat were lower in rats fed pectin. These findings indicate that dietary fibers regulate expression, function and distribution of apoptotic-related proteins in the crypt during colon carcinogenesis, changes that probably induce a reduction in tumor volume. We assume that butyrate, produced following fermentation of pectin, may play a key role in these effects.

Catheter-based plasmid-mediated transfer of genes into ischemic myocardium using the pCOR plasmid

BACKGROUND

Direct transfer of genes holds promise for the sustained delivery of therapeutic proteins to treat cardiovascular diseases. This can be accomplished by several approaches, including use of adenoviral vectors and naked plasmid DNA vectors. We previously demonstrated achieval of effective delivery of genes into the myocardium with a left ventricular-guided catheter-based approach using an adenoviral vector.

OBJECTIVE

To evaluate the levels and duration of expression of genes induced after injection of a specific plasmid vector, using the same delivery platform as that in our previous work.

METHODS

The pCOR plasmids are narrow-host-range plasmid vectors designed for nonviral gene therapy. We tested the ability of the pCOR plasmid vector to express its transgene after injection into the myocardium of pigs with chronic experimental ischemia using a catheter-based transendocardial delivery system. Four animals were subjected to transendocardial injections of the luciferase reporter pCOR gene into ischemic and nonischemic zones using the Biosense intramyocardial injection catheter. Injections (1 mg per animal, 50 micrograms per injection site) were performed at 20 sites in ischemic and nonischemic zones. Measurements of luciferase activity were performed 3 and 7 days thereafter.

RESULTS

We observed high levels of expression of luciferase gene in ischemic and nonischemic regions (on days 3 and 7, respectively, in ischemic zone 58,237 and 33,709 pg; in nonischemic zone 39,928 and 46,036 pg). Control noninjected samples from the left and right ventricles contained no detectable luciferase activity.

CONCLUSIONS

With a catheter-based approach, the pCOR plasmid was successfully used to deliver genes into designated myocardial regions, and provides sustained expression of protein for at least 7 days, of roughly similar magnitudes in ischemic and nonischemic myocardium.

Regional differences in optic disc and retinal circulation

PURPOSE

To determine regional differences in the circulation of the optic disc, the peripapillary choroid and the retinal vessels using the techniques of computerized image analysis and fluorescein angiography.

METHODS

Ten young normal subjects were studied. Fluorescein angiography was performed with a scanning laser ophthalmoscope. The rate of filling of fluorescein or slope was measured in the four quadrants of the optic disc, the peripapillary choroid and the major retinal arteries and veins. A total of 125 points was measured from each image of the fluorescein angiograms for a total of 20 to 30 images. Retinal vessel width was measured using computerized image analysis.

RESULTS

Comparison of the rates of filling of fluorescein or slopes showed significant differences from zero among the four quadrants of the optic disc (p= 0.01 to <0.02), of the peripapillary choroid (p=0.01 to <0.05) and among the major retinal arteries (p=0.01 to <0.02) and retinal veins (p=0.02 to <0.05). No significant differences were noted between the quadrants for retinal arterial width with the retinal veins only showing a significant difference between the inferior nasal and inferior temporal vein (p=0.02 to <0.05).

CONCLUSION

Evaluation of the circulation of the optic disc, retina, and peripapillary choroid should take into account regional differences among these structures.

Portal hypertension induces sodium channel expression in colonocytes from the distal colon of the rat

Cellular mechanisms for Na(+) retention in portal hypertension are undefined, but epithelial Na(+) channels (ENaC) may be involved. Under high-salt diet, ENaC are absent from distal colon of rat but can be induced by mineralocorticoids such as aldosterone. Presence of rat ENaC was determined by amiloride inhibition of (22)Na(+) uptake in surface colonocytes 7 and 14 days after partial portal vein ligation (PVL) or sham surgery. At both times, uptake inhibition was significantly increased in PVL rats. Presence of mRNA transcripts, determined by RT-PCR, demonstrated that channel alpha- and gamma-subunits were similarly expressed in both groups but that beta-subunit mRNA was increased in PVL rats. This confirms that there was induction of rat ENaC and indicates that beta-subunit has a regulatory role. Urinary Na(+) was decreased for 3 days after PVL but was not different at other times, and serum aldosterone levels were elevated at 7 days, at a time when urinary Na(+) output was similar to that of sham-operated rats. We conclude that PVL leads to induction of ENaC in rat distal colon. An increase in aldosterone levels may prevent natiuresis and is probably one of several control mechanisms involved in Na(+) retention in portal hypertension.

Association of ocular pressure and optic disc cup volume with red blood cell sodium-potassium ATPase inhibition

PURPOSE

To determine if there were significant differences between the number of red blood cell ouabain binding sites in normals and untreated ocular hypertensives plus one open-angle glaucoma patient.

METHODS

We measured the binding of (3)H ouabain to erythrocyte membranes of 23 normals, 25 ocular hypertensives and one open-angle glaucoma. We also measured the levels of plasma cortisol and digoxin in these subjects. Characteristics of cupping of the optic disc and thickness of the retinal nerve fiber layer, as well as area of optic disc pallor of these subjects were measured by stereophotogrammetry and by computerized image analysis from single and stereo photographs.

RESULTS

The number of (3)H ouabain binding sites was observed to be significantly less in the ocular hypertensives and one glaucoma compared to the normals (p = 0.0009). In multi-variate analyses, to determine what other factors affected this difference, there was a significant negative association with mean intraocular pressure (p = 0.003) (average of both eyes) and total cup volume (average of both eyes) (p = 0.005), diagnosis of ocular hypertension and glaucoma (p = 0.0005) and male gender (p = 0.019). There was a significant positive association with plasma cortisol levels (p = 0.048), and diastolic blood pressure (p = 0.037).

CONCLUSIONS

The number of (3)H ouabain binding sites in red blood cells decreases significantly with increasing ocular pressure and increasing cup volume indicating the possible presence of an increased systemic endogenous digoxin-like inhibitor and/or difference in the isozymes of Na(+), K(+)-ATPase which may be associated with increased levels of plasma cortisol in ocular hypertensives and glaucomas.

Crystal structure at 2.5 A resolution of zinc-substituted copper amine oxidase of Hansenula polymorpha expressed in Escherichia coli

Copper amine oxidases (CAOs) catalyze the two-electron oxidation of primary amines to aldehydes, utilizing molecular oxygen as a terminal electron acceptor. To accomplish this transformation, CAOs utilize two cofactors: a mononuclear copper, and a unique redox cofactor, 2,4,5-trihydroxyphenylalanine quinone (TPQ or TOPA quinone). TPQ is derived via posttranslational modification of a specific tyrosine residue within the protein itself. In this study, the structure of an amine oxidase from Hansenula polymorpha has been solved to 2.5 A resolution, in which the precursor tyrosine is unprocessed to TPQ, and the copper site is occupied by zinc. Significantly, the precursor tyrosine directly ligands the metal, thus providing the closest analogue to date of an intermediate in TPQ production. Besides this result, the rearrangement of other active site residues (relative to the mature enzyme) proposed to be involved in the binding of molecular oxygen may shed light on how CAOs efficiently use their active site to carry out both cofactor formation and catalysis.

Preparing for elimination of congenital Rubella syndrome (CRS): summary of a workshop on CRS elimination in the United States

The goal of eliminating indigenous rubella and congenital rubella syndrome (CRS) in the United States in the near future is now within reach, because rubella incidence has been sustained at record-low levels since the mid-1990s. Effective prevention strategies to eliminate CRS and rubella require improvement in the surveillance of CRS and congenital rubella infection (CRI). The purpose of the workshop was to review rubella and CRS epidemiology, as well as current clinical, diagnostic, and laboratory practices, to determine whether new strategies are needed to achieve and document CRS elimination. Workshop participants agreed that surveillance for CRS must be strengthened, particularly through augmented laboratory capabilities, and the case definition for CRS must be revised to reflect the current scientific information available. Further studies of methods are needed to identify high-risk populations and geographic areas for rubella and CRS and to enhance identification of infants with CRS.

Severe pneumococcal pneumonia in previously healthy children: the role of preceding influenza infection

An outbreak of severe pneumococcal pneumonia among children occurred in Iowa from November 1995 through January 1996. An associated outbreak of influenza disease was predominantly caused by influenza A (H1N1) for the first time since 1989. We conducted a case-control study to determine whether preceding influenza infection was directly associated with pneumococcal illness. We identified 13 children with severe pneumococcal pneumonia. Patients were more likely than control subjects to report experiencing an influenza-like illness in the 7-28 days preceding admission (matched odds ratio [OR], 12.4; 95% confidence interval [CI], 1.7-306). Likewise, family members of patients were more likely than those of control subjects to report experiencing an influenza-like illness in the 28 days preceding their admission date (OR, 2.6; 95% CI, 1.0-6. 3). Patients were more likely than control subjects to have a positive influenza A (H1N1) convalescent serology (matched OR, 3.7; 95% CI, 1.0-18.1). This study provides direct and indirect evidence that influenza infection led to severe pneumococcal pneumonia among these children. Prevention of pneumococcal disease should be included among the potential benefits of influenza vaccination.

Invasive group A streptococcal disease in children and association with varicella-zoster virus infection. Ontario Group A Streptococcal Study Group

OBJECTIVES

To describe the incidence and clinical features of invasive group A streptococcal (GAS) disease in children in Ontario and determine the risk of invasive GAS infection following chickenpox.

METHODS

During 1992-1996, we conducted prospective, active, population-based surveillance for pediatric invasive GAS disease in Ontario, Canada (population: 11 million; 2.5 million children) and reviewed clinical and laboratory records.

RESULTS

There were 1.9 cases of invasive GAS disease per 100,000 children per year. Streptococcal toxic shock syndrome (STSS) occurred in 7% of cases and necrotizing fasciitis (NF) in 4% for incidences of.08 and.13 per 100,000 per year, respectively. Case-fatality rates were 56% for STSS, 10% for NF, and 4% overall. The presence of chronic underlying illness other than asthma was associated with death (relative risk [RR]: 11; 95% confidence interval [CI]: 2.4-45). Fifteen percent of children identified had preceding chickenpox infection, which significantly increased the risk for acquisition of invasive GAS disease (RR: 58; 95% CI: 40-85). Children with invasive GAS and recent chickenpox were more likely to have NF (RR: 6.3; 95% CI: 1.8-22.3).

CONCLUSIONS

Childhood invasive GAS disease occurs at an incidence similar to the adult population but has a lower rate of STSS and case-fatality. Chickenpox dramatically increases the risk for acquiring invasive GAS disease, and universal chickenpox vaccination could potentially prevent up to 15% of all pediatric invasive GAS disease.

Antimicrobial resistance of nasopharyngeal isolates of Streptococcus pneumoniae and Haemophilus influenzae from children in the Central African Republic

BACKGROUND

To assist the Central African Republic (CAR) develop national guidelines for treating children with pneumonia, a survey was conducted to determine antimicrobial resistance rates of nasopharyngeal isolates of Streptococcus pneumoniae (SP) and Haemophilus influenzae (HI). Secondary purposes of the survey were to identify risk factors associated with carriage of a resistant isolate and to compare the survey methods of including only children with pneumonia vs. including all ill children.

METHODS

A cross-sectional survey of 371 ill children was conducted at 2 outpatient clinics in Bangui, CAR.

RESULTS

In all 272 SP isolates and 73 HI isolates were cultured. SP resistance rates to penicillin, trimethoprim-sulfamethoxazole (TMP-SMX), tetracycline and chloramphenicol were 8.8, 6.3, 42.3 and 9.2%, respectively. All penicillin-resistant SP isolates were intermediately resistant. HI resistance rates to ampicillin, TMP-SMX and chloramphenicol were 1.4, 12.3 and 0%, respectively. The most common SP serotypes/groups were 19, 14, 6 and 1; 49% of HI isolates were type b. History of antimicrobial use in the previous 7 days was the only factor associated with carriage of a resistant isolate. Resistance rates were similar among ill children regardless of whether they had pneumonia.

CONCLUSIONS

Resistance rates were low for antimicrobials recommended by the World Health Organization for children with pneumonia. We recommended TMP-SMX as the first line treatment for pneumonia in CAR because of its low cost, ease of dosing and activity against malaria.

Kinetic analysis of oxygen utilization during cofactor biogenesis in a copper-containing amine oxidase from yeast

A detailed kinetic analysis of oxygen consumption during TPQ biogenesis has been carried out on a yeast copper amine oxidase. O(2) is consumed in a single, exponential phase, the rate of which responds linearly to dissolved oxygen concentration. This behavior is observed up to conditions of maximally obtainable oxygen concentrations. In contrast, no viscosity effect is observed on rate, implicating a high K(m) for O(2). Binding of oxygen appears to occur faster than its consumption and to result in displacement of the precursor tyrosine onto copper to form a charge-transfer species, described in the the preceding paper of this issue [Dove, J. E., Schwartz, B., Williams, N. K., and Klinman, J. P. (2000) Biochemistry 39, 3690-3698). Reaction between this intermediate and O(2) is proposed to occur in a rate-limiting step, and to proceed more rapidly when the tyrosine is deprotonated. This rate-limiting step in cofactor biogenesis does not display a solvent isotope effect and is, thus, uncoupled from proton transfer. Comparisons are drawn between the proposed biogenesis mechanism and that for the oxidation of reduced cofactor during catalytic turnover in the mature enzyme.

Investigation of spectroscopic intermediates during copper-binding and TPQ formation in wild-type and active-site mutants of a copper-containing amine oxidase from yeast

Copper amine oxidases possess the unusual ability to generate autocatalytically their organic cofactor, which is subsequently utilized in turnover. This cofactor, 2,4,5-trihydroxyphenylalanine quinone (TPQ), is formed within the active site of these enzymes by the oxidation of a single tyrosine residue. In vitro, copper(II) and oxygen are both necessary and sufficient for the conversion of tyrosine to TPQ. In this study, the biogenesis of TPQ has been characterized in an amine oxidase from Hansenula polymorpha expressed as the apo-enzyme in Escherichia coli. With the WT enzyme, optical absorbances which are copper or oxygen dependent are observed and characterized. Active-site mutants are used to investigate further the nature of these spectral species. Evidence is presented which suggests that tyrosine is activated for reaction with oxygen by liganding to Cu(II). In the following paper in this issue [Schwartz, B., Dove, J. E., and Klinman, J. P. (2000) Biochemistry 39, 3699-3707], the initial reaction of precursor protein with oxygen is characterized kinetically. Taken together, the available data suggest a mechanism for the oxidation of tyrosine to TPQ where the role of the copper is to activate substrate.

Increased carriage of trimethoprim/sulfamethoxazole-resistant Streptococcus pneumoniae in Malawian children after treatment for malaria with sulfadoxine/pyrimethamine

Treatment of malaria with sulfadoxine/pyrimethamine and of presumed bacterial infections with trimethoprim/sulfamethoxazole (cotrimoxazole) was assessed to see if either increases the carriage of cotrimoxazole-resistant Streptococcus pneumoniae in Malawian children. Children <5 years old treated with sulfadoxine/pyrimethamine, cotrimoxazole, or no antimicrobial agent were enrolled in a prospective observational study. Nasopharyngeal swabs were taken before treatment and 1 and 4 weeks later. Pneumococci were tested for antibiotic susceptibility by broth microdilution. In sulfadoxine/pyrimethamine-treated children, the proportion colonized with cotrimoxazole-nonsusceptible pneumococci increased from 38.1% at the initial visit to 44.1% at the 4-week follow-up visit (P=.048). For cotrimoxazole-treated children, the proportion colonized with cotrimoxazole-nonsusceptible pneumococci increased from 41.5% at the initial visit to 52% at the 1-week follow-up visit (P=.0017) and returned to 41.7% at the 4-week follow-up. Expanding use of sulfadoxine/pyrimethamine to treat chloroquine-resistant malaria may have implications for national pneumonia programs in developing countries where cotrimoxazole is widely used.

Fungal keratitis after laser in situ keratomileusis: a case report

PURPOSE

To report a case of fungal keratitis resulting after laser in situ keratomileusis (LASIK).

METHODS

A 38-year-old white man in good health developed a corneal infiltrate with laboratory confirmation of fungal keratitis after LASIK. Corneal scrapings were taken. Silver stain was positive for hyphae. Culture was positive for Curvularia sp. The patient was started on intensive natamycin 5% and amphotericin 0.15% topical therapy.

RESULTS

The patient's keratitis was successfully treated with intensive antifungal therapy.

CONCLUSIONS

Infectious keratitis is a rare but a serious potential complication after LASIK. To our knowledge, no previous case of fungal keratitis after LASIK has been reported. This case emphasizes the importance of surveillance for infection after LASIK.

Evaluation of the circulation in the retina, peripapillary choroid and optic disk in normal-tension glaucoma

Computerized image analysis, including fluorescein angiography, was used to evaluate the retinal, choroidal and optic disk blood flow in 16 patients with normal-tension glaucoma (NTG) and to correlate this measurement with visual fields, retinal vessel width, optic disk pallor and blood pressure (BP). The angle of the ascending slope of the fluorescein dye curve was measured as an index of blood flow from the densitometric and time curves of the fluorescein angiograms in the optic disk, peripapillary choroid, retinal artery and vein for each quadrant. While the ascending slope as well as the retinal vessel width were most reduced in the inferior and nasal regions, the mean threshold was lowest in the superior and nasal quadrants. There were positive significant correlations between artery width and threshold value, between angles of slopes and pallor. In addition, systolic BP had a negative correlation with pallor, and diastolic BP had a positive one with slope in the choroid. These results indicated the probable association of a decrease in retinal, choroidal and optic disk blood flow in the inferior and nasal quadrants as well as vessel width in the inferior nasal quadrant with visual field loss in the superior quadrant, and also demonstrated an increasing blood flow for enlargement of pallor. A decrease in BP was found to be related to reduced blood flow in choroid and optic disk impairment.

The protective effect of estrogen against chemically induced murine colon carcinogenesis is associated with decreased CpG island methylation and increased mRNA and protein expression of the colonic vitamin D receptor

Epidemiological studies suggest that estrogen prevents neoplastic transformation in the intestinal mucosa. Estrogen was shown to increase the expression of vitamin D receptors (VDR) in a variety of tissues. 1,25-Dihydroxyvitamin D [1,25-(OH)2D] and several of its analogues are known as potent antineoplastic and prodifferentiative in many cell types, including colon-derived cells. The present study was designed to examine the effect of estradiol (E2) on dimethylhydrazine (DMH)-induced colon cancer in rats, and the possibility that E2 may exert its protective effect on the colon through modulation of the vitamin D-endocrine system. The in vivo effect of E2 on DMH-induced colorectal cancer was studied in four groups of ovariectomized female rats: (I) untreated control, (II) E2 treated, (III) DMH treated, and (IV) combined E2 and DMH treated. Significantly higher uterine weights and higher colonic estrogen receptor content confirmed the effectiveness of ovariectomy and E2 replacement. The number of malignant tumors in group IV was 2.3+/-1.1 (mean +/- SE) per rat, compared with 8.1+/-1.9 in group III (P < 0.001). Exposure to estrogen was associated with a marked increase in VDR mRNA content and VDR protein expression in the normal colonic mucosa. In tumor extracts VDR protein expression was considerably lower compared with normal mucosa. Estrogen treatment did not affect serum levels of 25(OH)D, 1,25(OH)2D, and PTH. Significant CpG island methylation in the VDR gene was observed in colonic tissue DNA harvested from rats treated with DMH, but not in colonic mucosae from rats treated with DMH + E2. The highest frequency of CpG methylation in the VDR gene was detected in DNA extracted from cancer tissue rims. In summary, the protective effect of estrogen against chemically induced colonic carcinogenesis is associated with reduced methylation of the VDR gene and with upregulation of both VDR gene transcription and protein expression. We suggest that estrogen may interfere with the process of CpG DNA methylation in the colonic mucosa to prevent silencing of the VDR gene. Increased VDR activity could be one of the mechanisms by which estrogen protects against neoplastic transformation in the colon.

Dietary regulation and localization of apoptosis cascade proteins in the colonic crypt

This study was designed primarily to assess the localization of apoptosis cascade proteins along the rat colonic crypt and secondarily to test whether the activity and/or localization of these proteins are affected by the enrichment of the diet with the soluble fiber pectin. Expression of apoptosis cascade proteins was assessed in isolated colonocytes harvested from the luminal and basal crypt colonocyte populations. Two different dietary regimens were tested: a standard diet (diet A), and a diet enriched in pectin (diet B), a soluble fiber that undergoes fermentation in the cecum and produces high concentrations of intracolonic short-chain fatty acids. Caspase-1 expression was maximal in luminal colonocytes of rats fed diet B, as evidenced by Western blot and immunohistological analyses. Expression of the cleaved poly(ADP-ribose) polymerase product was elevated in both the luminal and basal colonocytes of the pectin-fed group, whereas in rats fed diet A, the expression was lower, especially in basal crypt colonocytes. The highest expression of the antiapoptotic protein Bcl-2 was observed in the lower compartments of the colonic crypt tissue and was maximal in the rat group fed a standard diet. The apoptotic index in colonocytes of rats fed diet B was higher than that measured in rats fed diet A. Cumulatively, our results indicate that apoptosis cascade proteins are differentially localized along the lumen-crypt axis, and their expression and activity may be controlled by dietary components. These results may, at least partially, account for the documented protective effect of butyrogenic fibers on colorectal cancer.

Impact of azithromycin on oropharyngeal carriage of group A Streptococcus and nasopharyngeal carriage of macrolide-resistant Streptococcus pneumoniae

BACKGROUND

Invasive group A streptococcal (GAS) infections are a cause of serious morbidity and high mortality. There is a need for a simple, effective antimicrobial regimen that could be used to prevent invasive GAS disease in high risk situations. To assess azithromycin as a chemoprophylactic agent, we evaluated its efficacy for eradication of oropharyngeal (OP) GAS and its impact on the nasopharyngeal (NP) colonization rate of macrolide-resistant Streptococcus pneumoniae.

METHODS

We obtained OP and NP swabs for GAS and pneumococcus culture, respectively, from 300 schoolmates of a child with an invasive GAS infection. GAS culture-positive students were treated with daily azithromycin (12 mg/kg/day) for 5 days. We obtained follow-up OP and NP swabs at 9 (Day 17) and 24 (Day 32) days post-treatment from those students identified as GAS carriers on Day 0 and determined macrolide susceptibility of GAS and pneumococcal isolates.

RESULTS

Of the 300 students swabbed 152 (50%) carried GAS in their oropharynx. On Day 17, efficacy of azithromycin for GAS eradication was 95% (140 of 147) for all students. NP colonization rates for pneumococci decreased from 46% (67 of 146) to 12% (17 of 144; P < 0.001) by Day 17 and to 20% (27 of 137; P < 0.001) by Day 32. The prevalence of erythromycin-resistant pneumococcal isolates increased from 2% (3 of 146) to 4% (6 of 144) by Day 17 and to 8% (11 of 137; P = 0.04) by Day 32.

CONCLUSIONS

Azithromycin is an effective short course regimen for eradication of oropharyngeal GAS. However, azithromycin selected for macrolide-resistant strains of pneumococci. These findings highlight the importance of determining the appropriate circumstances for antimicrobial prophylaxis to prevent invasive GAS infections.

Estrogen controls expression and bioresponse of 1,25-dihydroxyvitamin D receptors in the rat colon

Estrogen receptors are extensively expressed in the gastrointestinal tract, however their physiological role is not clear yet. Estrogen and 1,25-dihydroxyvitamin D [1,25(OH)2D3] apparently share common activities in the intestine such as growth-suppressing effects on the colonic mucosa and positively influence intestinal calcium absorption. In view of our previous studies showing up-regulation of vitamin D receptors (VDR) in the duodenal mucosa and in osteoblasts, the present study was designed to address a possible interaction between estrogen and the vitamin D endocrine system in the colonic mucosa. Three groups of female rats were studied: sham operated ('Sham'), ovariectomized ('OVX'), and ovariectomized estrogen-treated ('OVX+E'). VDR gene expression was assessed by Northern blot analysis, VDR protein expression was assessed by ligand-binding assays, and Western-blotting. Endogenous 1,25(OH)2D3 bioactivity in colonic mucosal extracts was assessed by alkaline phosphatase activity and calbindin-9kD mRNA expression. Northern blots revealed marked increase in band intensity corresponding with the VDR mRNA product in 'Sham' or 'OVX+E' vs. 'OVX'. In ligand-binding experiments, 1,25(OH)2D3 was shown to bind specifically to a single class of receptors in extracts obtained from each of the groups (Kd--0.03 nM). The maximal VDR binding capacity of colonic mucosal extracts was 203 +/- 23 fmol/mg protein in 'Sham', 362 +/- 41 in 'OVX+E' and 102 +/- 15 in 'OVX' ('Sham' or 'OVX+E' vs. 'OVX', p < 0.001). Western-blot analysis also revealed higher VDR protein expression in the estrogen-exposed animals. Alkaline phosphatase activity and calbindin-9kD mRNA expression were significantly higher in colonic mucosal extracts from estrogen-exposed rats. Estrogen increases VDR gene transcript level, protein expression and endogenous 1,25(OH)2D3 bioactivity in colonic mucosa, which may suggest that some of the estrogen activities in the colonic mucosa, such as its growth-suppressing effect, could be mediated, at least in part, by an increase in colonic mucosa responsiveness to endogenous 1,25(OH)2D3.

Butyrate regulates E-cadherin transcription, isoform expression and intracellular position in colon cancer cells

Cell-to-cell adhesion, an important event in differentiation, is impaired during advanced stages of tumorigenesis. In this study, we examined the possible regulation of cell-adhesion proteins by the differentiation agent butyrate in LS174T and HM7 cells, two types of human colon cancer cells that differ in their ability to produce mucin and colonize the liver of experimental animals. The more aggressive, high-mucin-producing cell line (HM7), a clone selected from LS174T cells, showed a scattered and undifferentiated ultramorphological appearance and low basal alkaline phosphatase activity; the proteins beta-catenin and E-cadherin, as detected by immunostaining, were expressed in the cells' nuclei. All of these properties were significantly less pronounced in the less aggressive, low-mucin-producing LS174T cells. In both cell lines, butyrate treatment enhanced cell-to-cell interaction, alkaline phosphate activity, translocation of beta-catenin and E-cadherin from the nuclei to the membrane junctions, and transcription and translation of the 120-kDa E-cadherin isoform, but not of its 100-kDa isoform. Analysis of possible mechanisms of E-cadherin up-regulation revealed that butyrate induces the release of nuclear proteins from the E-cadherin promoter sequence, reducing transcription repression. We suggest that butyrate activates E-cadherin transcription through translocation of nuclear transcription factors bearing specific repressor activity. We surmise that abrogation of nuclear 100-kDa E-cadherin and beta-catenin expression following butyrate treatment is related to the control of E-cadherin gene transcription.

Self-determination. The tyranny of freedom

Americans now live in a time and a place in which freedom and autonomy are valued above all else and in which expanded opportunities for self-determination are regarded as a sign of the psychological well-being of individuals and the moral well-being of the culture. This article argues that freedom, autonomy, and self-determination can become excessive, and that when that happens, freedom can be experienced as a kind of tyranny. The article further argues that unduly influenced by the ideology of economics and rational-choice theory, modern American society has created an excess of freedom, with resulting increases in people's dissatisfaction with their lives and in clinical depression. One significant task for a future psychology of optimal functioning is to deemphasize individual freedom and to determine which cultural constraints are necessary for people to live meaningful and satisfying lives.

Antimicrobial use for pediatric upper respiratory infections: reported practice, actual practice, and parent beliefs

BACKGROUND

In response to the dramatic emergence of resistant pneumococci, more judicious use of antibiotics has been advocated. Physician beliefs, their prescribing practices, and the attitudes of patients have been evaluated previously in separate studies.

METHODS

This 3-part study included a statewide mailed survey, office chart reviews, and parent telephone interviews. We compared survey responses of 366 licensed pediatricians and family physicians in Georgia to recently published recommendations on diagnosis and treatment of upper respiratory infections (URIs). We further evaluated 25 randomly selected pediatricians from 119 surveyed in the Atlanta metropolitan area. For each, charts from the first 30 patients between the ages of 12 and 72 months seen on a randomly selected date were reviewed for encounters during the preceding year. A sample of parents from each practice were interviewed by telephone.

RESULTS

In the survey, physicians agreed that overuse of antibiotics is a major factor contributing to the development of antibiotic resistance (97%), and that they should consider selective pressure for resistance in their decisions on providing antibiotic treatment for URIs in children in their practices (83%). However, many reported practices do not conform to the recently published principles for judicious antibiotic use. For example, 69% of physicians considered purulent rhinitis a diagnostic finding for sinusitis; 86% prescribed antibiotics for bronchitis regardless of the duration of cough; and 42% prescribed antibiotics for the common cold. Reported practices by family physicians were more often at odds with the published principles: they were significantly more likely than pediatricians to omit pneumatic otoscopy (46% vs 25%); to omit the requirement for prolonged symptoms to diagnose sinusitis (median 4 vs 10 days); and to omit laboratory testing for pharyngitis (27% vs 14%). Of the 7531 encounters analyzed in the chart review, 43% resulted in an antibiotic prescription, including 11% of checkups, 18% of telephone calls, and 72% of visits for URIs. There was wide variability in the overall antibiotic use rates among the 25 physicians (1-10 courses per child per year). There was an even wider variability in some diagnosis-specific rates; bronchitis and sinusitis in particular. Those with the highest antibiotic prescribing rates had up to 30% more return office visits. Physicians who prescribed antibiotics for purulent rhinitis were more likely to see parents who believed that their children should be evaluated for cold symptoms.

CONCLUSIONS

Physicians recognize the problem of antibiotic resistance but their reported practices are not in line with recently published recommendations for most pediatric URIs. The actual prescribing practices of pediatricians are often considerably different from their close colleagues. Patient beliefs are correlated with their own physician's practices.

Rapid selection of complement-inhibiting protein variants in group A Streptococcus epidemic waves

Serotype M1 group A Streptococcus strains cause epidemic waves of human infections long thought to be mono- or pauciclonal. The gene encoding an extracellular group A Streptococcus protein (streptococcal inhibitor of complement) that inhibits human complement was sequenced in 1,132 M1 strains recovered from population-based surveillance of infections in Canada, Finland and the United States. Epidemic waves are composed of strains expressing a remarkably heterogeneous array of variants of streptococcal inhibitor of complement that arise very rapidly by natural selection on mucosal surfaces. Thus, our results enhance the understanding of pathogen population dynamics in epidemic waves and infectious disease reemergence.

In colorectal carcinoma patients, serum vitamin D levels vary according to stage of the carcinoma

BACKGROUND

Epidemiologic studies have demonstrated an inverse correlation between dietary calcium and vitamin D intake and the incidence of colorectal carcinoma. Elevated serum levels of 25-hydroxyvitamin D3 (25-OH-D3) are associated with a major reduction in the incidence of this neoplasm. The reduction in tumor size and number induced by calcium supplements in an experimental carcinogenesis model was neutralized by vitamin D3 deficiency. To the authors' knowledge, vitamin D serum levels have never been determined previously in colorectal carcinoma patients. They compared serum 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), 25-OH-D3, and parathyroid hormone (PTH) levels of colorectal carcinoma patients with those of healthy controls.

METHODS

Serum 1,25(OH)2D3, 25-OH-D3, and PTH levels were determined in 84 colorectal carcinoma patients (10 with Stage I, 29 with Stage II, 25 with Stage III, and 20 with Stage IV) and 30 healthy controls, all of whom were normocalcemic and not taking calcium or vitamin D supplements.

RESULTS

25-OH-D3 serum levels were higher in cancer patients than controls, irrespective of stage. Serum 1,25(OH)2D3 decreased with advancing stage: 73 +/- 18, 48 +/- 16, 39 +/- 12, 34 +/- 13, and 75 +/- 20 pg/mL in Stages I, II, III, IV, and controls, respectively. There was a corresponding increase in serum PTH levels: 58.0 +/- 9.4, 73.7 +/- 14.4, 79.0 +/- 21.3, 100.4 +/- 30.9, and 51.2 +/- 3.9 pg/mL in Stages I, II, III, IV, and controls, respectively. Serum vitamin D metabolite levels did not correlate with gender, age, tumor localization, or histologic grade.

CONCLUSIONS

An inverse correlation between serum levels of the active metabolite of vitamin D and colorectal carcinoma stage has been demonstrated for the first time, to the authors' knowledge, in colorectal carcinoma patients. Because 1,25(OH)2D3 has been shown to inhibit proliferation of colonic epithelial cells, decreased serum levels may facilitate the growth of colorectal carcinoma and influence its biologic behavior.

Reduced plasma cortisol binding to albumin in ocular hypertension and primary open-angle glaucoma

PURPOSE

To compare plasma cortisol binding as well as total plasma cortisol, free cortisol and percent free cortisol in normals, ocular hypertensives and primary high pressure open-angle glaucomas.

METHODS

Blood samples were obtained on outpatient visits of 18 normals, 19 ocular hypertensives and 18 primary open-angle glaucomas. Plasma cortisol binding was determined after the endogenous steroids were removed by charcoal absorption. Scatchard analysis was used to determine both the affinity of binding and the cortisol binding capacity of corticosteroid binding globulin and albumin. Plasma total and free cortisol were measured by radioimmunoassay.

RESULTS

Both the ocular hypertensive and the open-angle glaucomas in comparison to normals were found to have a highly significant reduced cortisol binding capacity to albumin (p = 0.006) with a borderline significantly increased binding affinity to plasma corticosteroid binding globulin (p = 0.0495) and no significant difference in binding affinity to albumin or cortisol binding capacity to plasma globulin. Both the ocular hypertensives and the open-angle glaucomas in comparison to normals were found to have significantly elevated levels of free cortisol (p = 0.012) and percent free cortisol (p = 0.003). Multivariate analyses showed that the reduced cortisol binding capacity to albumin was significantly associated with an increased percent free cortisol, with ocular hypertension and open-angle glaucoma and with male gender.

CONCLUSION

Both ocular hypertension and primary open-angle glaucoma are associated with elevated levels of plasma free cortisol which are related to a reduced cortisol binding capacity to albumin.

Diversity of response of optic nerve head circulation to timolol maleate in gel-forming solution

PURPOSE

This randomized, double-masked, placebo-controlled, two-period crossover study was conducted to investigate the effects of 0.5% timolol maleate in gel-forming solution on intraocular pressure (IOP) and blood circulation in the optic nerve head in patients with untreated ocular hypertension.

METHODS

The effects of 0.5% timolol in gel-forming solution on IOP and optic nerve head capillary blood speed were studied in 12 patients with untreated ocular hypertension. Optic nerve capillary blood speed was measured using the laser Doppler technique before and at the end of each treatment period.

RESULTS

In each patient, IOP decreased after treatment with timolol (mean decrease 16.8% versus placebo). Systemic blood pressure and pulse rate did not differ significantly after treatment with topical timolol from values after placebo. The mean change from baseline in Doppler broadening was 10.6% greater after treatment with timolol than after placebo. There was no significant change in mean Doppler broadening from baseline after treatment with either timolol or placebo. However, optic nerve head capillary blood speed increased in six patients, and was within the range of placebo response in six patients after treatment with timolol. Spearman correlation analysis of the baseline with Doppler broadening measurements after treatment showed a correlation for placebo but not for timolol. The percent change in Doppler broadening after timolol treatment was correlated with iris color.

CONCLUSION

These results indicate that administration of timolol for 4 weeks reduces IOP in patients with ocular hypertension and generally does not change the blood circulation in the optic nerve head. Individual patients, however, showed variable changes in optic nerve head circulation after topical administration of timolol. Although the sample size was small, these changes in optic nerve head circulation were correlated with iris color.

High-efficiency gene transfer into skeletal muscle mediated by electric pulses

Gene delivery to skeletal muscle is a promising strategy for the treatment of muscle disorders and for the systemic secretion of therapeutic proteins. However, present DNA delivery technologies have to be improved with regard to both the level of expression and interindividual variability. We report very efficient plasmid DNA transfer in muscle fibers by using square-wave electric pulses of low field strength (less than 300 V/cm) and of long duration (more than 1 ms). Contrary to the electropermeabilization-induced uptake of small molecules into muscle fibers, plasmid DNA has to be present in the tissue during the electric pulses, suggesting a direct effect of the electric field on DNA during electrotransfer. This i.m. electrotransfer method increases reporter and therapeutic gene expression by several orders of magnitude in various muscles in mouse, rat, rabbit, and monkey. Moreover, i.m. electrotransfer strongly decreases variability. Stability of expression was observed for at least 9 months. With a pCMV-FGF1 plasmid coding for fibroblast growth factor 1, this protein was immunodetected in the majority of muscle fibers subjected to the electric pulses. DNA electrotransfer in muscle may have broad applications in gene therapy and in physiological, pharmacological, and developmental studies.

Intravenous immunoglobulin therapy for streptococcal toxic shock syndrome--a comparative observational study. The Canadian Streptococcal Study Group

Twenty-one consecutive patients with streptococcal toxic shock syndrome (TSS) between December 1994 and April 1995 were treated with a median dose of 2 g of intravenous immunoglobulin (IVIG)/kg (cases) and were compared with 32 patients with streptococcal TSS between 1992 and 1995 who did not receive IVIG therapy (controls). The outcome measure was 30-day survival. Patient plasma was tested for its ability to inhibit T cell activation induced by the infecting strain. The proportion of cases with 30-day survival was higher than that of the controls with 30-day survival (67% vs. 34%, respectively; P = .02). Multivariate analysis revealed that IVIG administration and a lower Acute Physiology and Chronic Health Evaluation II score were associated with survival; the odds ratio for survival associated with IVIG therapy was 8.1 (95% confidence interval, 1.6-45; P = .009). IVIG therapy enhanced the ability of patient plasma to neutralize bacterial mitogenicity and reduced T cell production of interleukin-6 and tumor necrosis factor alpha. IVIG may be an effective adjunctive therapy for streptococcal TSS, possibly because of its ability to neutralize bacterial exotoxins.

Risk factors in the pathogenesis of invasive group A streptococcal infections: role of protective humoral immunity

An impressive change in the epidemiology and severity of invasive group A streptococcal infections occurred in the 1980s, and the incidence of streptococcal toxic shock syndrome cases continues to rise. The reason for the resurgence of severe invasive cases remains a mystery-has there been a change in the pathogen or in host protective immunity? To address these questions, we have studied 33 patients with invasive infection caused by genotypically indistinguishable M1T1 strains of Streptococcus pyogenes who had different disease outcomes. Patients were classified as having severe (n = 21) and nonsevere (n = 12) invasive infections based on the presence or absence of shock and organ failure. Levels of anti-M1 bactericidal antibodies and of anti-streptococcal superantigen neutralizing antibodies in plasma were significantly lower in both groups than in age- and geographically matched healthy controls (P < 0.01). Importantly, the levels of these protective antibodies in plasma samples from severe and nonsevere invasive cases were not different. Together the data suggest that low levels of protective antibodies may contribute to host susceptibility to invasive streptococcal infection but do not modulate disease outcome. Other immunogenetic factors that regulate superantigen responses may influence the severity of systemic manifestations associated with invasive streptococcal infection.

Invasive group A streptococcal infections in children

Invasive group A streptococcal infections and STSS have increased as causes of morbidity and mortality among children and adults. In children, respiratory foci appear to be the most common, but skin and soft tissue infection, particularly associated with varicella, also are common. Early diagnosis requires awareness of the presenting features and a high index of suspicion. Antimicrobial therapy that includes clindamycin, therapy with IVIG for those with STSS, and surgical intervention for patients with necrotizing fasciitis may improve outcome. Chemoprophylaxis should be considered among household contacts of patients with severe group A streptococcal disease in high-risk settings. Further studies are ongoing to evaluate the hypothesized link of invasive group A streptococcal infection in children with varicella and NSAID use, to better clarify the pathogenesis of STSS and necrotizing fasciitis, and to better document the risk of secondary spread among close contacts of case patients.

Risk factors for invasive pneumococcal disease in children: a population-based case-control study in North America

OBJECTIVE

To identify risk factors for invasive pneumococcal disease, including penicillin-resistant infections, among children 2 to 59 months of age.

DESIGN

Case-control study.

PARTICIPANTS

Patients with invasive pneumococcal infections identified by population-based surveillance (n = 187) and controls identified through random-digit telephone dialing (n = 280).

OUTCOME MEASURES

Invasive pneumococcal disease was defined as isolation of Streptococcus pneumoniae from a normally sterile site. Patients 2 to 59 months of age who were residents of one of four active surveillance areas were included. S pneumoniae isolates were tested by broth microdilution. Isolates with a minimum inhibitory concentration to penicillin >/=2 microg/mL were considered resistant.

RESULTS

Invasive pneumococcal disease was strongly associated with underlying disease and with day care attendance in the previous 3 months. Among 2- to 11-month-olds, current breastfeeding was associated with a decreased likelihood of invasive pneumococcal disease (odds ratio, 0.27; 95% confidence interval: 0.08, 0.90). Penicillin-resistant infections were independently associated with day care attendance, at least one course of antibiotics, and at least one ear infection in the previous 3 months.

CONCLUSIONS

This study shows the association of underlying illnesses, day care attendance, and lack of breastfeeding with risk of invasive pneumococcal disease in children. The association of recent antibiotic use and infection with penicillin-resistant S pneumoniae highlights the need to avoid unnecessary antibiotic use in children.

Minicircle: an improved DNA molecule for in vitro and in vivo gene transfer

Minicircles are a new form of supercoiled DNA molecule for nonviral gene transfer which have neither bacterial origin of replication nor antibiotic resistance marker. They are thus smaller and potentially safer than the standard plasmids currently used in gene therapy. They were obtained in E. coli by att site-specific recombination mediated by the phage lambda integrase, which was used to excise the expression cassette from the unwanted plasmid sequences. We produced two minicircles containing the luciferase or beta-galactosidase gene under the control of the strong human cytomegalovirus immediate-early enhancer/promoter. Comparing maximal differences, these minicircles gave 2.5 to 5.5 times more reporter gene activity than the unrecombined plasmid in the NIH3T3 cell line and rabbit smooth muscle cells. Moreover, injection in vivo into mouse cranial tibial muscle, or human head and neck carcinoma grafted in nude mice resulted in 13 to 50 times more reporter gene expression with minicircles than with the unrecombined plasmid or larger plasmids. Histological analysis in muscle showed there were more transfected myofibers with minicircles than with unrecombined plasmid.