Killing of the Yeast and Hyphal Forms of Candida albicans Using a Light-Activated Antimicrobial Agent

Oral infections due to Candida albicans are a common occurrence in patients with acquired immunodeficiency syndrome (AIDS). The purpose of this investigation was to determine whether the yeast and hyphal forms of the organism could be killed using the light-activated antimicrobial agent toluidine blue O (TBO). Three variables were investigated: TBO concentration, laser light dose and pre-irradiation time (PIT). Irradiation with light from a helium neon (HeNe) gas laser used in conjunction with the photosensitiser TBO resulted in substantial kills of both the yeast and hyphal forms. Killing was light dose-dependent with 42 J being the most effective dose. The optimum PIT for the yeast form was 5 min, whereas killing of the hyphal form was not affected by PIT. The results of this study have shown that both forms of C. albicans are susceptible to lethal photosensitisation using TBO in conjunction with HeNe laser light, suggesting the possibility that this approach could be useful for eliminating the organism from diseased lesions in vivo. Paper received 14 July 1997; accepted after revision 26 November 1998.     

Endogenous Porphyrin Production in Bacteria by δ-Aminolaevulinic Acid and Subsequent Bacterial Photoeradication

. In the present study we examined the effects of the accumulation of endogenous porphyrins on the microorganisms Staphylococcus aureus and Escherichia coli. δ-Aminolaevulinic acid (δ-ALA) 50 μg/ml can induce production of large amounts of porphyrins when incubated with the bacteria in the dark. This porphyrin production within the cells was examined directly by a fluorescence activated cell sorter (FACS) instrument and a significant increase in red fluorescence was observed. Incubation of δ-ALA with these microorganisms did not slow down their growth. δ-ALA or δ-ALA methyl ester induced accumulation of uroporphyrin in S. aureus cells and excretion of coproporphyrin into the growth medium. In E. coli, these inducers resulted in the accumulation of uroporphyrin and protoporphyrin within the cells and excretion of coproporphyrin and protoporphyrin from the cells. Photoinactivation of the porphyrin-loaded bacteria can be achieved by various light sources, depending on the dose. The most effective photokilling of S. aureus and of E. coli by its endogenic porphyrins was achieved by blue light (400–450 nm) at approximately 50 J/cm². With red light (600–700 nm), a 10-fold higher light dose was required to get a similar result for S. aureus killing. With a laser beam (632.8 nm), 50 J/cm² was necessary for 3 orders of decrease in the viability of S. aureus. With white light, 75 J/cm² was needed for 2–3 orders of decrease of S. aureus viability. With the last two light sources eradication of E. coli required at least 10 times higher doses of light. It seems that S. aureus is more susceptible than E. coli to photosensitisation when it is loaded with endogenous porphyrins. Ultrastructural alterations were observed in the bacteria incubated with δ-ALA in the dark and photosensitised by blue light (400–450 nm). Filamentous chromosomes were observed in E. coli, whereas honeycomb mesosomes were observed in S. aureus, with a destruction of the area around these mesosomes in the chromosomal area. The method described here is an additional approach to the photoinactivation of bacteria by porphyrins, with photoinactivation being accomplished by endogenous porphyrins. Paper received 6 October 1998; accepted after revision 12 April 1999.     

Bactericidal effects of different laser wavelengths on periodontopathic germs in photodynamic therapy

 This study was an attempt to clarify whether the bactericidal effects of photodynamic therapy (PDT) are wavelength or dose-dependent. We also attempted to create an optimised protocol for a light-based bactericidal modality to eliminate periodontal pathogens. Cultures of Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Porphromonas gingivalis, Prevotella intermedia, and Streptococcus sanguis, were exposed to a He-Ne laser (632.8 nm) with a 30 mW power output, a 100 mW diode laser at 665 nm, or a 100 mW diode laser at 830 nm, in the presence or absence of methylene blue (MB) as a photosensitiser. A control group was also used with exposure to MB alone without laser exposure. The cultures were analysed by viable counts. The results indicated that exposure to the 100 mW laser light could eliminate up to 40% of bacteria on average. In particular, the most effective killing occurred with exposure to laser light in combination with the MB photosensitiser. The results of kinetic studies indicated that the best PDT response rate was achieved with a 60 s (energy density 21.2 J/cm²) exposure to the 665 nm wavelength diode laser in the presence photosensitiser. In this condition, approximately 95% of A. actinomycetemcomitans and F. nucleatum, and 99–100% of the black-pigmented bacteria (P. gingivalis and P. intermedia) and S. sanguis were eliminated. These results showed that both wavelength and energy density are important factors, and that a low power laser of optimal wavelength and dosage, in combination with an appropriate photosensitiser, is a practical bactericidal modality. We concluded that using a diode laser of proper power and wavelength to deliver 60 s of irradiation could be a useful adjunct with mechanical debridement in the prevention of the re-colonisation of subgingival lesions by pathogenic microorganisms. Received: 29 November 2001 / Accepted: 18 June 2002     

The effect of noncoherent red light irradiation on proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells

Mesenchymal stem cells (MSCs) are promising for use in regenerative medicine. Low-level light irradiation (LLLI) has been shown to modulate various processes in different biological systems. The aim of our study was to investigate the effect of red light emitted from a light-emitting diode (LED) on bone marrow MSCs with or without osteogenic supplements. MSCs both with and without osteogenic supplements were divided into four groups, and each group was irradiated at doses of 0, 1, 2 and 4 J/cm². Cellular proliferation was evaluated using WST-8 and 5-ethynyl-2′-deoxyuridine (EdU) fluorescence staining. The alkaline phosphatase activity, mineralization, and expression of osteoblast master genes (Col1α1, Alpl, Bglap and Runx2) were monitored as indicators of MSC differentiation towards osteoblasts. In groups without osteogenic supplements, red light at all doses significantly stimulated cellular proliferation, whereas the osteogenic phenotype of the MSCs was not enhanced. In groups with osteogenic supplements, red light increased alkaline phosphatase activity and mineralized nodule formation, and stimulated the expression of Bglap and Runx2, but decreased cellular proliferation. In conclusion, nonconherent red light can promote proliferation but cannot induce osteogenic differentiation of MSCs in normal media, while it enhances osteogenic differentiation and decreases proliferation of MSCs in media with osteogenic supplements.     

Outcome of accidental peritoneal dialysis catheter holes or tip exposure

Pediatric peritoneal dialysis (PD) patients are at risk for acute peritonitis. One risk factor is accidental exposure of the catheter to a non-sterile surface. We studied catheter exposures in 17 pediatric patients receiving PD who developed 16 holes and 12 other accidental exposures. The rate of exposures was 3.7 events/100 patient-months. After exposure, the mean counts (± standard error) of white blood cells (WBC), red blood cells, and neutrophils were 39.8 ± 19.3, 9.5 ± 7.1, and 24.2 ± 5.3/mm³, respectively. There was a trend towards higher peritoneal fluid WBC in patients with holes than in those with exposures (60.1 ± 34.8 vs. 15.4 ± 5.1/mm³, respectively; p = 0.2). The initial peritoneal fluid WBC count was significantly higher if there was a positive culture than a negative culture (165.0 ± 132.6 vs. 20.3 ± 6.4/mm³, respectively; p = 0.01). The percentage of neutrophils was higher in patients with a positive culture than in those with a negative culture (54.7 ± 14.1 vs. 19.1 ± 4.9%, respectively; p = 0.01). Of the 28 patients, 27 received a single dose of intravenous antibiotics, as per the protocol at that time. Among those treated, 7% developed a positive culture (all staphylococcal species) while 93% had a negative culture. We conclude that following accidental exposure of the peritoneal dialysis catheter: (1) the prevalence of peritonitis is low; (2) measuring peritoneal fluid WBC provides treatment guidance; (3) if treatment is initiated, it should be applied intraperitoneally and include activity against Gram-positive organisms.     

Effects of bone and mineral metabolism on arterial elasticity in chronic renal failure

Arterial stiffness (Ast) individually predicts cardiovascular (CV) mortality. Ast increases via vascular calcification and can be characterized by pulse wave velocity (PWV). We assessed the influence of mineral and bone metabolism on Ast in dialyzed (D) and renal transplanted (Tx) children by measuring fetuin-A and bone markers [bone-specific alkaline phosphatase (BALP); beta-CrossLaps (β)]. Normalized PWV/height (PWV/h) of 11 D and 17 Tx patients was measured by applanation tonometry. Levels of calcium (Ca), phosphate (P), fetuin-A, and bone markers were analyzed. Ca × P/fetuin-A ratio was calculated to characterize the balance of calcification and inhibition. Cumulative dose of calcitriol was also assessed. Fetuin-A was lower in D and Tx compared with healthy controls. Bone markers and Ca × P/fetuin-A of D were significantly higher than those of Tx and controls. In D PWV/h correlated with Ca × P/fetuin-A and BALP (r = 0.8; p = 0.005, r = 0.6, p = 0.05, respectively); BALP correlated with Ca × P/fetuin-A (r = 0.7, p = 0.01). In Tx, there was a correlation between calcitriol administered before transplantation and PWV/h (r = 0.5, p = 0.04). Increased bone turnover was coupled with an increased potential of calcium-phosphate precipitation, as shown by the increased Ca × P/fetuin-A. It might explain the connection between disturbed mineral and bone metabolism and Ast. Tx might be beneficial on Ast, though follow-up studies are needed.     

Antibacterial Effect of Yellow He-Ne Laser Irradiation with Crystal Violet Solution on Porphyromonas gingivalis: An Evaluation Using Experimental Rat Model Involving Subcutaneous Abscess

. A study was conducted to evaluate the antibacterial effect of yellow He-Ne laser irradiation with crystal violet solution (CV) on Porphyromonas gingivalis (P.g.). Paper points were soaked with a P.g. suspension (10⁹ ml) with 0.8 mg/l CV added, laser-irradiated for 60 s (laser group), and implanted subcutaneously on the back of rats. Three additional groups were studied: CV group: the paper point was soaked with the P.g. suspension plus 0.8 mg/l CV, but laser irradiation was not performed; P.g. group: the paper point was soaked with the P.g. suspension only and laser irradiation was not performed; control group: the paper point was soaked with sterilised isotonic sodium chloride solution and laser irradiation was not performed. Seven days after implantation, block sections of all implanted sites were examined histologically. The abscess area in the laser group was smaller than in the P.g. group or CV group, but larger than in the control group. The number of inflammatory cells was greatest in the P.g. and CV groups, with fewer in the laser group and still fewer in the control group. The results indicate that a yellow He-Ne laser with 0.8 mg/l CV solution exerts an antibacterial effect in vivo. Paper received 12 July 1999; accepted after revision 24 March 2000.     

Optimal conditions for successful ablation of high-grade dysplasia in Barrett’s oesophagus using aminolaevulinic acid photodynamic therapy

Photodynamic therapy (PDT) using 5-aminolaevulinic acid (ALA-PDT) is an attractive alternative to PDT with porfimer sodium for the treatment of high-grade dysplasia (HGD) in Barrett’s oesophagus (BO) because of the shorter duration of light photosensitivity and low risk of oesophageal stricture formation. Published results, however, show marked variation in its efficacy, and optimum treatment parameters have not been defined. This study investigated how the dose of ALA and the colour of the illuminating light influenced the biological effect. Twenty-seven patients were enrolled into a randomised controlled trial of red versus green (635 nm or 512 nm) laser light activation for the eradication of HGD with ALA-PDT in Barrett’s oesophagus. A further 21 patients were subsequently treated with the most effective regimen. Regular endoscopic follow-up with quadrantic biopsies every 2 cm was performed. The primary outcome measure was eradication of HGD. Patient’s receiving ALA at 30 mg/kg relapsed to HGD more than those receiving 60 mg/kg (P = 0.03). Additionally, for those treated with ALA 60 mg/kg, red laser light was more effective than green laser light (P = 0.008). Kaplan–Meier analysis of the 21 patients who were subsequently treated with this optimal regimen demonstrated an eradication rate of 89% for HGD and a cancer-free proportion of 96% at 36 months’ follow-up. Using an ALA dose of 60 mg/kg activated by 1,000J/cm red laser light, we found that ALA-PDT was a highly effective treatment for high-grade dysplasia in Barrett’s oesophagus.     

Inhibitory effect of bikunin on calcium oxalate crystallization in vitro and urinary bikunin decrease in renal stone formers

Two proteins of 17 and 24 kDa, respectively, which were immunologically related to bikunin, were purified from urine of healthy men, using in the last step a trypsin CNBr-sepharose affinity column. These proteins strongly inhibited calcium oxalate (CaOx) crystallization in two in vitro models. In the first model, the presence of 8 μg/ml protein in a medium containing 0.76 mM CaCl₂ (with ⁴⁵Ca) and 0.76 mM ammonium oxalate inhibited the crystallization process by 80%, as estimated by supernatant radioactivity after 60 min of incubation. A similar inhibition was observed in the second turbidimetric model, where the CaOx crystallization kinetics were followed for 10 min at 620 nm in a medium containing 4 mM CaCl₂ and 0.5 mM Na₂Ox. These proteins were used as standard protein for the development of an enzyme-linked immunosorbent assay (ELISA) in urine. Mean (± SEM) urinary bikunin concentration in 18 healthy subjects was 5.01 ± 0.91 μg/ml. This was a concentration range of strong inhibitory activity in vitro. Bikunin values were nearly 50% lower (2.54 ± 0.42 μg/ml, P=0.007) in 31 CaOx renal stone formers (having weddelite crystals in their first morning urine) than in the healthy volunteers. A correlation was found between urinary bikunin and alpha-1 microglobulin concentrations in the control group (y=0.73x + 1.09, r ²=0.8) while no such correlation existed in the lithiasis group. In conclusion, bikunin exerts a strong inhibitory action of CaOx crystallization in vitro. Its involvement in urinary CaOx crystallization of stone formers is highly probable, based on the significant decrease in its urinary concentration in the majority of stone formers studied. Received: 16 December 1997 / Accepted: 23 June 1998     

Epithelial sodium channels expressed in <Emphasis Type="Italic">Xenopus</Emphasis> oocytes are activated by cyclic-AMP

Background. The regulation of the epithelial sodium channel (ENaC) is a key determinant of sodium homeostasis. The effect of cyclic AMP (cAMP) on ENaC activity is tissue-specific, and is controversial when ENaC is ex-pressed in Xenopus oocytes. Methods. The modulation of ENaC by cAMP in oocytes expressing human or rat ENaC was performed with two-electrode voltage clamping. Results. 250 μM 8-(4-chlorophenylthio)-adenosine 3′, 5′-cyclic monophosphate (8-CPT-cAMP) added to the bath significantly increased normalized amiloride-sensitive currents within 60 s in oocytes expressing human α, β, and γ subunits (5 ng cRNA each). The cAMP effect was dose-dependent and was partially inhibited by 200 μM Rp-CPT-cAMP, a competitive cAMP antagonist. A transient effect of 8-CPT-cAMP on rat ENaC activity was also observed. Oocytes expressing rat α subunits with γ subunits (which have a putative protein kinase A phosphorylation site) showed similar increases in amiloride-sensitive current with 250 μM 8-CPT-cAMP, while oocytes expressing rat α subunits with β subunits were not activated by 8-CPT-cAMP. Further, rat ENaC (but not human ENaC)-expressing oocytes were not activated by cAMP when oocytes were continuously superfused during electrophysiological recordings, suggesting that rat ENaC activation by cAMP is dependent upon the condition of oocytes during cAMP stimulation. Conclusion. The present results suggest that ENaC expressed in Xenopus oocytes can be activated by cAMP, and that the γ subunit confers sensitivity to cAMP modulation of rat ENaC activity. Received: February 21, 2002 / Accepted: June 26, 2002 Acknowledgments We thank Dr. M.J. Welsh for providing the human ENaC clones and Dr. B.C. Rossier for providing the rat ENaC clones. We sincerely appreciate the technical help of Dr. Sunil Saxena and Mr. Darryl Morin. We also thank Martha Yeager for her secretarial support. This work was supported in part by grants from the National Institute of Health, NS-34877 (YO), DK-19407, and DK-53161 (DGW); the Robert Wood Johnson Foundation MMFDP (JKT); and the WM Keck Foundation (MWQ). Correspondence to:K. Tamba     

Urinary excretion of tubular proteins and the technetium-99m dimercaptosuccinic acid (DMSA) absolute renal uptake in partial ureteral obstruction in rats: a functional evaluation of hydronephrotic kidneys

The aim of this longitudinal study was to evaluate tubular proteinuria in rats with unilateral (UPO) and bilateral (BPO) partial ureteral obstruction with the dimercaptosuccinic acid (DMSA) scan as the gold standard for measuring renal tubular damage. We studied 70 female Wistar rats: 28 animals with UPO, 28 animals with BPO, 7 sham-operated animals, and 7 controls. All animals with obstructed ureters showed renal dilatation on the diethylenetriaminepentaacetic acid DTPA images 1 and 5 weeks postoperatively. One week following UPO and BPO, tubular proteinuria and urinary N-acetyl-beta-d-glucosaminidase (NAG) activity increased (P < 0.01) and the absolute DMSA uptake decreased (P < 0.01). Persistently (week 6) high tubular proteinuria was found in 29% of the animals and was related to severe damage on the DMSA scan (P < 0.01) and to albuminuria (P < 0.05). Renal tubular damage was demonstrated by measuring renal enzymes, tubular proteins, and DMSA uptake after UPO and BPO. Persistent elevated tubular proteinuria was related to severely damaged kidneys. Received: 18 June 1998 / Accepted: 20 October 1998     

The effect of a single episode of antimicrobial photodynamic therapy in the treatment of experimental periodontitis. Microbiological profile and cytokine pattern in the dog mandible

The purpose of this study was to evaluate the effect of a single application of antimicrobial photodynamic therapy (aPDT) on microbiological profile and cytokine pattern in dogs. Periodontal disease was induced by placing 3.0 silk ligatures around the mandibular pre-molars bilaterally during 8 weeks. The dogs were randomly treated with aPDT using a dye/laser system, scaling and root planning (SRP), or with the association of treatments (SRP + aPDT). Plaque samples were collected at baseline, 1, 3, and 4 weeks, and the mean counts of 40 species were determined using DNA-DNA hybridization. Gingival biopsies were removed and the expression of tumor necrosis factor alpha (TNF-α), receptor activator of NF-kB ligand (RANKL), osteoprotegerin (OPG), matrix metalloproteinase (MMP-1), interleukin (IL) 6, IL-10 and total bacterial load by analysis of 16 S rRNA gene were evaluated through real-time PCR. The results shows that the levels of the majority of the species were reduced 1 week post-therapy for all treatments, however, an increase in counts of Prevotella intermedia (p = 0.00), Prevotella. nigrescens (p = 0.00) and Tannerella forsythia (p = 0.00) was observed for aPDT and SRP + aPDT. After 4 weeks, a regrowth of Porphyromonas gingivalis (p = 0.00) and Treponema denticola (p = 0.00), was observed for all treatments. Also, a strikingly reduction of counts on counts of Aggregatibacter actinomycetemcomitans was observed for the aPDT (p = 0.00). For the cytokine pattern, the results were similar for all treatments, and a reduction in the expression of cytokines and bacterial load was observed throughout the study. Our results suggest that SRP, aPDT in a single application, and SRP + aPDT affects different bacterial species and have similar effects on the expression of cytokines evaluated during the treatment of ligature-induced periodontitis.     

Quantification of fibrosis and mast cells in the tissue response of endodontic sealer irradiated by low-level laser therapy

Low-level laser therapy (LLLT) accelerates tissue repair. Mast cells induce the proliferation of fibroblasts and the development of local fibrosis. The objective of this study was to quantify fibrosis rate and mast cells in connective tissue after endodontic sealer zinc oxide and eugenol (ZOE) was implanted and submitted to LLLT, immediately after implant and again 24 h later. Sixty mice were distributed into three groups: GI, GII, and GIII (n = 20). In GI, the tubes filled with Endofill were implanted in the animals and were not irradiated with LLLT. In GII, the tubes containing Endofill were implanted in the animals and then irradiated with red LLLT (InGaAIP) 685-nm wavelength, D = 72 J/Cm², E = 2 J, T = 58 s, P = 35 mW, and in GIII, the tubes with Endofill were implanted and irradiated with infrared LLLT (AsGaAl) 830-nm wavelength, D = 70 J/Cm², E = 2 J, T = 40 s, P = 50 mW. After 7 days and 30 days, the animals were killed. A series of 6-μm-thick sections were obtained and stained with Toluidine Blue and Picrosirius and analyzed under a standard light microscope using a polarized light filter for the quantification of fibrosis. The statistics were qualitative and quantitative with a significance of 5%. The irradiation with LLLT did not offer improvement in the fibrosis rate, however, it provided a significant decrease in the concentration of independent mast cells for the period studied.     

Muscarinic receptor subtypes in porcine detrusor: comparison with humans and regulation by bladder augmentation

The properties of muscarinic acetylcholine␣receptors of porcine and human bladder detrusor were␣compared in radioligand binding studies using [³H]quinuclidinylbenzylate as the radioligand. The receptor affinity for the radioligand and the density of␣muscarinic receptors was similar in male and female pigs and in humans (K _d = 35 ± 8 pM, B _max = 153 ± 30 fmol/mg protein). Atropine and subtype-selective antagonists had steep and monophasic competition curves in porcine and human detrusor with a rank order of potency of atropine ≫ hexahydro-sila-difenidol ≥ AF-DX 116 ≥ pirenzepine, indicating the presence of a␣homogeneous population of M₂ muscarinic receptors. In female pigs bladder outflow obstruction generated by partial urethral ligation or its surgical treatment by ileum augmentation or autoaugmentation did not significantly alter expression of muscarinic receptors or of α_2A-adrenoceptors, but the power was insufficient to exclude alterations of less than 60%. We conclude that porcine and human detrusor express muscarinic receptors of the M₂ subtype; despite these qualitative similarities the use of the porcine model may be limited by large biological variance with regard to quantitative receptor expression. Received: 9 June 1997 / Accepted: 27 October 1997     

Pneumatosis Intestinalis in Adults: Management,Surgical Indications,and Risk Factors for Mortality

Background Pneumatosis intestinalis (PI) is an unusual finding that can exist in a benign setting but can indicate ischemic bowel and the need for surgical intervention. We present a series of cases of PI in adults to illustrate factors associated with death and surgical intervention. Methods We reviewed the radiology database of the Mount Sinai Medical Center for cases of PI between 1996–2006 in adult patients. Chi-square and multivariable logistic regression analyses were used to identify factors significant for surgery and death. Results Forty patients developed PI over a 10-year span. The overall in-hospital mortality rate was 20%, and the surgical rate was 35%. Factors independently associated with surgical management on multivariable analysis were age ≥ 60 years (p = 0.03), the presence of emesis (p = 0.01), and a WBC > 12 c/mm³ (p = 0.03). Pre-existing sepsis was independently associated with mortality (p = 0.03) while controlling for surgery. Conclusion Patients with the concomitant presence of PI, a WBC > 12 c/mm³, and/or emesis in the >60-year-old age group were most likely to have surgical intervention, whereas PI patients with sepsis had the highest risk for death. A management algorithm is proposed, but further research will be needed to determine which patients with PI may benefit most from surgery.     

Investigation of arginine A-specific cysteine proteinase gene expression profiling in clinical <Emphasis Type="Italic">Porphyromonas gingivalis</Emphasis> isolates against photokilling action of the photo-activated disinfection

Porphyromonas gingivalis is a significant root canal pathogen capable of causing endodontic infections, which during their treatment may receive sub-lethal doses of photo-activated disinfection (sPAD). As sPAD can influence microbial virulence, this study was designed to evaluate the effect of sPAD on gene expression level of arginine A-specific cysteine proteinase (rgpA), as one of the underlying virulence factors involved in the development of endodontic infection via P. gingivalis strains. To find out the sPAD against 16 clinical isolates of PAD-resistant P. gingivalis that were isolated in vivo, we used toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) as the photosensitizers, which were excited with specific wavelength of light in vitro. Quantitative real-time PCR (qRT-PCR) was then applied to monitor gene expression of rgpA in P. gingivalis isolates to characterize its virulence agent and understand the effect of sPAD on its pathogenicity. Maximal sPAD that could not decrease the count of P. gingivalis isolates were 6.25, 15.6, and 25 μg/mL at fluencies of 171.87, 15.6, and 93.75 J/cm² for TBO, ICG, and MB, respectively. ICG-sPAD could suppress the rgpA gene expression about 14-fold, while MB and TBO-mediated sPAD could cause the attenuation of rgpA expression about 4.9- and 11.6-fold, respectively. ICG-sPAD with the maximum ability to reduce rgpA gene expression compared with other photosensitizers can be an appropriate candidate for the treatment of endodontic infections.     

Resistance against broad-spectrum β-lactams among uropathogens in children

The aim of this study was to investigate the prevalence trends and risk factors for urinary tract infection (UTI) caused by Enterobacteriaceae resistant to broad-spectrum β-lactams in children. All Enterobacteriaceae uropathogens from children <15 years during the 11-year period 1997–2007 were included, and risk factors were evaluated. Of 523 Enterobacteriaceae isolated from 473 children, 30 (5.73%) were phenotypically resistant to broad-spectrum β-lactams (18 Escherichia coli, ten Klebsiella spp, one Enterobacter spp, and one Citrobacter spp). The prevalence of resistance increased during the study period (p = 0.031). Resistance to cefoxitin was common (26/30), pointing to AmpC enzyme expression, and 2/30 isolates were resistant to carbapenems. Resistant Enterobacteriaceae were often community acquired (22/30, 73.3%) and related to male gender (p < 0.05), urinary tract abnormalities (p < 0.05), prophylactic antibiotics (p < 0.0001), longer hospitalization (p < 0.001), and UTI recurrences (p < 0.001). Co-resistance was more likely for cotrimoxazole, gentamicin, and ciprofloxacin (p < 0.0001). In conclusion, our study points to increasing prevalence of Enterobacteriaceae uropathogens resistant to broad-spectrum β-lactams in the community setting, which limits the utility of first-line antibiotics and questions the validity of using prophylaxis after a first UTI episode.     

Intensive Insulin Therapy and Bone Mineral Density in Type 1 Diabetes Mellitus: A Prospective Study

To determine the effect of metabolic control on bone mineral density (BMD) in type 1 diabetes mellitus (type 1 DM), we studied BMD (by dual-energy X-ray energy absorptiometry) and bone remodeling parameters in 62 patients with type 1 DM both before and 7 years after commencement of intensive insulin therapy. Overall outcomes after the 7-year treatment included the stabilization of BMD at all sites, as well as a significant decrease in tartrate-resistant acid phosphatase (TRAP) (4.302 ± 2.62 vs 2.65 ± 0.97 IU/l; p = 0.0001) and increase in intact parathyroid hormone (PTHi) (28.05 ± 15.7 vs 39.78 ± 22.41 ng/l; p = 0.005). Presence of diabetic retinopathy (RTP) versus its absence (non-RTP) was associated with lower BMD in femoral neck (FN) (0.831 ± 0.142 vs 0.756 ± 0.153 mg/cm²; p = 0.03) and Ward’s triangle (WT) (0.736 ± 0.165 vs 0.632 ± 0.172 mg/cm²; p = 0.03), and with a lower T-score in FN (–0.93 ± 1.34 vs –1.70 ± 1.46; p = 0.04) and WT (–0.72 ± 1.42 vs –1.540 ± 1.55; p = 0.04) and Z-score in FN (–0.591 ± 1.23 vs –1.132 ± 1.46; p = 0.01). The percentage of patients with osteopenia or osteoporosis in the RTP group was significantly higher than in the non-RTP group (72% vs 53%, p = 0.05; RR= 3.2) and the glycosylated hemoglobin (HbA1c) levels of the RTP group were also higher (8.53 ± 1.6% vs 7.1 ± 1.1%; p = 0.05). The improvement in metabolic control, increase in body mass index and decrease in resorption parameters could contribute to the stabilization of bone mass in type 1 DM but the presence of retinopathy is a critical factor in the progression of diabetic osteopenia. Received: 4 June 1999 / Accepted: 16 November 1999     

Ca2+-ATPase in hard tissue forming cells

Conclusions We have shown that in active odontoblasts of the rat incisor tooth, used as a model system for hard tissue forming cells, two enzymes capable of degrading ATP exist. One can be inhibited by levamisole and R 8231 and is probably identical with non-specific alkaline phosphatase (APase). The activity of the other enzyme, tentatively named “Ca-ATPase”, is dependent on the presence of Ca²⁺ or Mg²⁺ and is activated by these ions. The “Ca-ATPase” is unaffected by ouabain and ruthenium red. It may be speculated that the “Ca-ATPase” is concerned with the transmembraneous transport of Ca²⁺ ions to be mineralization front.