Reduced Sliding Friction of Lubricant-Impregnated Catheters.

During urethral catheterization, sliding friction can cause discomfort and even hemorrhaging. In this report, we use a lubricant-impregnated polydimethylsiloxane coating to reduce the sliding friction of a catheter. Using a pig urethra attached to a microforce testing system, we found that a lubricant-impregnated catheter reduces the sliding friction during insertion by more than a factor of two. This suggests that slippery, lubricant-impregnated surfaces have the potential to enhance patient comfort and safety during catheterization.

Point-of-care rapid immunoassay performed on voided urine, refrigerated up to 24 hours, accurately detects bacteriuria.

OBJECTIVE: To collect voided urine from dogs with clinical signs of lower UTI and determine the diagnostic performance of a commercially available rapid immunoassay (RIA) immediately after urine collection and after refrigeration at 4 and 24 hours. ANIMALS: 40 client-owned dogs. METHODS: Aerobic urine culture was performed on urine collected by cystocentesis. Urine samples were collected by voiding, and the RIA performed in triplicate within 30 minutes (time 0) and again in triplicate after 4 and 24 hours of refrigeration. Test precision and agreement between culture results and RIA results at each time point were determined, and factors possibly associated with false results investigated. RESULTS: 14 of 40 dogs (35%) had UTI verified by aerobic urine culture, and all had positive RIA. Three dogs had false positive RIA results. Sensitivity, specificity, positive predictive value, and negative predictive value of the RIA were 100, 88%, 82%, and 100%, respectively, and results were not different after 4 and 24 hours of refrigeration. Precision was excellent. CLINICAL RELEVANCE: This point-of-care RIA, performed on voided urine refrigerated up to 24 hours, rapidly and accurately identifies bacteriuria in dogs with lower urinary tract clinical signs, inexpensively.

Cardiovascular function, pulmonary gas exchange and tissue oxygenation in isoflurane-anesthetized, mechanically ventilated Beagle dogs with four levels of positive end-expiratory pressure.

OBJECTIVES: To compare pulmonary gas exchange, tissue oxygenation and cardiovascular effects of four levels of end-expiratory pressure: no positive end-expiratory pressure (ZEEP), positive end-expiratory pressure (PEEP) of maximal respiratory system compliance (PEEPmaxCrs), PEEPmaxCrs + 2 cmH2O (PEEPmaxCrs+2), PEEPmaxCrs + 4 cmH2O (PEEPmaxCrs+4), in isoflurane-anesthetized dogs. STUDY DESIGN: Prospective randomized crossover study. ANIMALS: A total of seven healthy male Beagle dogs, aged 1 year and weighing 10.2 ± 0.7 kg (mean ± standard deviation). METHODS: The dogs were administered acepromazine and anesthesia was induced with propofol and maintained with isoflurane. Ventilation was controlled for 4 hours with ZEEP, PEEPmaxCrs, PEEPmaxCrs+2 or PEEPmaxCrs+4. Cardiovascular, pulmonary gas exchange and tissue oxygenation data were evaluated at 5, 60, 120, 180 and 240 minutes of ventilation and compared using a mixed-model anova followed by Bonferroni test. p < 0.05 was considered significant. RESULTS: Cardiac index (CI) and mean arterial pressure (MAP) were lower in all PEEP treatments at 5 minutes when compared with ZEEP. CI persisted lower throughout the 4 hours only in PEEPmaxCrs+4 with the lowest CI at 5 minutes (2.15 ± 0.70 versus 3.45 ± 0.94 L minute-1 m-2). At 180 and 240 minutes, MAP was lower in PEEPmaxCrs+4 than in PEEPmaxCrs, with the lowest value at 180 minutes (58 ± 7 versus 67 ± 7 mmHg). Oxygen delivery index (DO2I) was lower in PEEPmaxCrs+4 than in ZEEP at 5, 60, 120 and 180 minutes. Venous admixture was not different among treatments. CONCLUSION AND CLINICAL RELEVANCE: The use of PEEP caused a transient decrease in MAP and CI in lung-healthy dogs anesthetized with isoflurane, which improved after 60 minutes of ventilation in all levels of PEEP except PEEPmaxCrs+4. A clinically significant improvement in arterial oxygenation and DO2I was not observed with PEEPmaxCrs and PEEPmaxCrs+2 in comparison with ZEEP, whereas PEEPmaxCrs+4 decreased DO2I.

Diagnostic accuracy of a point-of-care test using voided urine samples for detection of bacteriuria in dogs with signs of lower urinary tract disease.

BACKGROUND: Bacterial urine culture is recommended in dogs suspected of having urinary tract infection (UTI), but there is expense and delay in obtaining such results. HYPOTHESIS/OBJECTIVE: To determine the diagnostic performance of a rapid immunoassay (RIA) dipstick for detection of bacteriuria using voided urine from dogs with clinical signs of lower UTI. ANIMALS: Twenty-four client-owned dogs. METHODS: Voided urine was collected and the RIA performed within 30 minutes. Urine collected by cystocentesis was submitted for aerobic urine culture. McNemar's test and kappa coefficient were calculated to determine agreement between the 2 tests. RESULTS: Nine of 21 dogs (43%) had UTI verified by aerobic urine culture. There was 1 false-negative and no false-positive RIA results. Sensitivity, specificity, positive predictive value, and negative predictive value of the RIA were 89%, 100%, 100%, and 92%, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: This RIA is promising for correctly identifying whether or not voided urine samples from dogs with lower urinary tract clinical signs have true bacteriuria in a rapid, inexpensive manner. Additional patients should be enrolled in a similar study to determine if diagnostic performance is robust in a large population.

Prevalence of, and factors associated with, positive urine cultures in hyperthyroid cats presenting for radioiodine therapy.

OBJECTIVES: Urinary tract infections (UTIs) are reported to be relatively common in hyperthyroid cats, with prevalence rates ranging from 12% to 22%. Factors that are associated with UTIs include age, decreasing body weight and active urine sediments. The purpose of this study was to investigate the prevalence of positive urine cultures (PUCs) in hyperthyroid cats and associated risk factors for PUC. METHODS: In total, 197 hyperthyroid cats presenting for radioiodine therapy had urine cultures prospectively performed on cystocentesis samples. Data pertaining to clinical signs, drug history, age, weight, blood urea nitrogen, creatinine, serum thyroxine and urinalysis were also evaluated. RESULTS: The prevalence of PUCs in this population of hyperthyroid cats was 5.1% and all cats were subclinical. Microscopic bacteriuria was significantly associated with a PUC (60%) compared with a negative urine culture (1.6%) status. Age, weight, urine specific gravity <1.020, urine pH, hematuria, pyuria, thyroxine concentration, breed and sex were not associated with PUC status. CONCLUSIONS AND RELEVANCE: The prevalence of PUCs in this population of cats was lower than previous reports of cats with hyperthyroidism. Cats with a PUC were subclinical at the time of culture, regardless of urine sediment abnormalities. Further studies are necessary to determine the clinical significance of subclinical bacteriuria in hyperthyroid cats.

Subclinical bacteriuria and surgical site infections in dogs with cranial cruciate ligament disease.

OBJECTIVE: To determine the prevalence of subclinical bacteriuria (SBU) in dogs with cranial cruciate ligament (CCL) disease, the clinical variables and clinicopathologic data associated with SBU, and the incidence of surgical site infections (SSI) in dogs with and without SBU. STUDY DESIGN: Prospective, clinical cohort study. ANIMALS: One hundred fifty-five dogs with CCL disease. METHODS: Dogs had a urinalysis, sediment examination, and aerobic urine culture performed. Age, breed, sex, body weight, body condition score, clinical history, and physical examination findings were recorded. Dogs with SBU were not treated for bacteriuria or with postoperative antibiotics. Standard perioperative antimicrobials were provided for all dogs. Dogs that received nonsteroidal anti-inflammatory drugs were not excluded. Dogs that underwent an osteotomy were followed for at least 1 year to determine incidence of SSI. Outcomes and variables associated with SBU were assessed. RESULTS: In 155 dogs with CCL disease, the prevalence of SBU was 6.5%, and SBU occurred exclusively in female dogs (11.4%). The incidence of SSI was 22.3% (25/112). Two of six dogs with SBU and 23/106 dogs without SBU developed SSI. Organisms isolated from SSI were different from those isolated from urine. CONCLUSION: The prevalence of SBU in dogs with CCL disease was similar to that in other studies in which SBU was evaluated in various populations of dogs. CLINICAL SIGNIFICANCE: Screening for and treatment of SBU may not be beneficial prior to tibial osteotomy for CCL disease. Additional studies are required to determine whether dogs with SBU have a greater risk of SSI.

Measurement of preprandial and postprandial urine calcium to creatinine ratios in male Miniature Schnauzers with and without urolithiasis.

BACKGROUND: We aimed to identify a simple test for excessive calciuresis and predict calcium oxalate (CaOx) disease in Miniature Schnauzers. We investigated the impact of postprandial time on the urine calcium to creatinine ratio (UCa/Cr) in male dogs of this breed, with the goal of improving the utility of the UCa/Cr. HYPOTHESES: (1) Significant differences will exist in preprandial and postprandial UCa/Cr between CaOx urolith-forming and control Schnauzers. (2) The UCa/Cr will increase significantly from the first morning baseline at ≥1 postprandial time point(s) in both control and CaOx urolith-forming dogs. (3) Biochemical abnormalities and other variables may be associated with urolith status. ANIMALS: Twenty-four male Miniature Schnauzer dogs, consisting of 9 with (urolith formers) and 15 without (controls) CaOx uroliths. METHODS: Urine was collected before and 1, 2, 4, and 8 hours after feeding a standardized diet. Receiver operator characteristic curve analysis was performed to identify the UCa/Cr cutoff that most accurately differentiates dogs based on urolith status. RESULTS: Urolith formers had significantly higher mean UCa/Cr over the course of 8 hours. The postprandial change in UCa/Cr was not significant at any time point between or within groups. The cutoff UCa/Cr value of 0.06 had a specificity of 93% (95% confidence interval [CI], 80%-100%) and a sensitivity of 56% (95% CI, 21%-86%) for identifying CaOx urolithiasis. CONCLUSIONS AND CLINICAL IMPORTANCE: Urolith-forming male Miniature Schnauzers have excessive calciuresis, and the postprandial sampling time up to 8 hours is not critical. This simple urine measurement has potential as a marker of CaOx disease.

Pathogenesis of calcium oxalate urinary stone disease: species comparison of humans, dogs, and cats.

Idiopathic calcium oxalate nephrolithiasis is a highly recurrent disease that is increasing in prevalence. Decades of research have not identified effective methods to consistently prevent the formation of nephroliths or induce medical dissolution. Idiopathic calcium oxalate nephroliths form in association with renal papillary subepithelial calcium phosphate deposits called Randall's plaques (RPs). Rodent models are commonly used to experimentally induce calcium oxalate crystal and stone formation, but a rodent model that conclusively forms RPs has not been identified. Both dogs and cats form calcium oxalate uroliths that can be recurrent, but the etiopathologic mechanisms of stone formation, especially renal pathologic findings, are a relatively unexploited area of study. A large animal model that shares a similar environment to humans, along with a shorter lifespan and thus shorter time to recurrence, might provide an excellent means to study preventative and therapeutic measures, along with enhancing the concepts of the one health initiative. This review article summarizes and compares important known features of idiopathic calcium oxalate stone disease in humans, dogs, and cats, and emphasizes important knowledge gaps and areas for future study in the quest to discover a naturally occurring animal model of idiopathic calcium oxalate stone disease.

Recurrent urethral fibroepithelial polyps in a golden retriever.

A 2 yr old castrated male golden retriever was referred multiple times over a period of 7.5 yr for stranguria, pollakiuria, urinary incontinence and urinary outflow obstructions due to urethral polyps. Diagnostic imaging modalities used to identify polyps included abdominal ultrasound, excretory urography, double-contrast retrograde urethrocystograms, and urethrocystoscopy, which revealed multiple filling defects within the proximal and prostatic urethra. Multiple cystotomies and endourologic procedures were performed to remove the multiple fibroepithelial polyps within the proximal and prostatic urethra. Urinary incontinence resulted from treatments, but did respond to phenylpropanolamine. Medical treatment consisted of a nonsteroidal anti-inflammatory drug, which appeared to decrease the recurrence of the polyps over time. Urethral polyps are an uncommon cause of urinary outflow obstruction and do not usually recur after removal. This case illustrates an uncommon clinical presentation and the difficulties encountered in treatment over an expanded time frame.

Effects of oral prednisone administration with or without ultralow-dose acetylsalicylic acid on coagulation parameters in healthy dogs.

OBJECTIVE: To determine the effects of oral prednisone administration with or without ultralow-dose acetylsalicylic acid on coagulation parameters in healthy dogs and to assess intraindividual variation in thromboelastography results. ANIMALS: 14 healthy research dogs and 10 healthy client-owned dogs. PROCEDURES: In a randomized controlled trial, research dogs underwent thromboelastography twice (3 days apart), and intraindividual variation in test results was calculated. Dogs were given prednisone (2 mg/kg/d, PO) plus acetylsalicylic acid (0.5 mg/kg/d, PO) or prednisone (2 mg/kg/d, PO) plus a placebo for 14 days, after which thromboelastography and other tests were repeated. Differences from preadministration (baseline) test results between and within groups were compared. In a separate trial, client-owned dogs also underwent thromboelastography twice 2 days apart to assess intraindividual variation in untreated dogs. RESULTS: Intraindividual variation in thromboelastography results for research dogs was ≤ 10% for maximum amplitude (MA) and α angle. In the research dogs, MA and fibrinogen values significantly increased from baseline, whereas percentage lysis 30 minutes after attainment of the MA as well as antithrombin activity significantly decreased within each group. In the dogs that received prednisone plus a placebo, percentage lysis 60 minutes after attainment of the MA was significantly lower than at baseline. For all parameters for research dogs, there was no difference between groups for change from baseline. Intraindividual variation in findings for client-owned dogs was similar to the variation for research dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Prednisone administration resulted in hypercoagulability in healthy dogs as indicated by an increase in MA and plasma fibrinogen concentration and a decrease in antithrombin activity. Concurrent ultralow-dose acetylsalicylic acid use had no effect on measured thromboelastography values. The high intraindividual variation in some thromboelastography parameters may preclude routine use of this technique in clinical practice.

Survival of a feline isolate of Tritrichomonas foetus in water, cat urine, cat food and cat litter.

Feline intestinal trichomoniasis caused by Tritrichomonas foetus is associated with large bowel diarrhea in cats from many parts of the world. It has long been recognized as an economically important sexually transmitted disease that causes early abortion in cattle. Isolates of T. foetus from cattle are infectious for the large intestine of cats and isolates of T. foetus from cats are infectious for the reproductive system of cattle. The parasite is maintained by fecal-oral transmission in cats. The present study was conducted to examine the survival of a feline isolate of T. foetus, AUTf-12, under various conditions that are relevant to fecal-oral transmission in cats. Trophozoites were grown in TYM medium and then exposed to water, cat urine, dry cat food, canned cat food, clumping cat litter, or filter paper for various lengths of time and then re-cultured in TYM medium. Trophozoites survived exposure to distilled or tap water for 30 but not 60 min, while they survived for at least 180 min in urine. Trophozoites survived for 30 min on dry cat food but survived for 120-180 min in canned cat food. No survival of trophozoites was observed on cat litter but trophozoites survived for 15 min when placed on filter paper. Our results indicate that T. foetus can survive and be potentially infectious in water, urine, dry cat food and canned cat food.

Fiberoptic microneedles: novel optical diffusers for interstitial delivery of therapeutic light.

BACKGROUND AND OBJECTIVES: Photothermal therapies have limited efficacy and application due to the poor penetration depth of light inside tissue. In earlier work, we described the development of novel fiberoptic microneedles to provide a means to mechanically penetrate dermal tissue and deliver light directly into a localized target area.This paper presents an alternate fiberoptic microneedle design with the capability of delivering more diffuse, but therapeutically useful photothermal energy. Laser lipolysis is envisioned as a future clinical application for this design. MATERIALS AND METHODS: A novel fiberoptic microneedle was developed using hydrofluoric acid etching of optical fiber to permit diffuse optical delivery. Microneedles etched for 10, 30, and 50 minutes, and an optical fiber control were compared with three techniques. First, red light delivery from the microneedles was evaluated by imaging the reflectance of the light from a white paper.Second, spatial temperature distribution of the paper in response to near-IR light (1,064 nm, 1 W CW) was recorded using infrared thermography. Third, ex vivo adipose tissue response during 1,064 nm, (5 W CW)irradiation was recorded with bright field microscopy. RESULTS: Acid etching exposed a 3 mm length of the fiber core, allowing circumferential delivery of light along this length. Increasing etching time decreased microneedle diameter, resulting in increased uniformity of red and 1,064 nm light delivery along the microneedle axis. For equivalent total energy delivery, thinner microneedles reduced carbonization in the adipose tissue experiments. CONCLUSIONS: We developed novel microscale optical diffusers that provided a more homogeneous light distribution from their surfaces, and compared performance to a flat-cleaved fiber, a device currently utilized in clinical practice. These fiberoptic microneedles can potentially enhance clinical laser procedures by providing direct delivery of diffuse light to target chromophores, while minimizing undesirable photothermal damage in adjacent, non-target tissue.

Serological response of cats to experimental Besnoitia darlingi and Besnoitia neotomofelis infections and prevalence of antibodies to these parasites in cats from Virginia and Pennsylvania.

Besnoitia darlingi and Besnoitia neotomofelis are cyst-forming tissue apicomplexan parasites that use domestic cats (Felis domesticus) as definitive hosts and opossums (Didelphis virginiana ) and Southern Plains woodrats (Neotoma micropus) as intermediate hosts, respectively. Nothing is known about the prevalence of B. darlingi or B. neotomofelis in cats from the United States. Besnoitia darlingi infections have been reported in naturally infected opossums from many states in the United States, and B. neotomofelis infections have been reported from Southern Plains woodrats from Texas, but naturally infected cats have not been identified. The present study examined the IgG antibody response of cats to experimental infection (B. darlingi n  =  1 cat; B. neotomofelis n  =  3 cats). Samples from these cats were used to develop an indirect immunofluorescent antibody test (IFAT), which was then used to examine seroprevalence of IgG antibodies to tachyzoites of B. darlingi and B. neotomofelis in a population of domestic cats from Virginia (N  =  232 cats) and Pennsylvania (N  =  209). The serum from cats inoculated with B. darlingi or B. neotomofelis cross-reacted with each other's tachyzoites. The titers to heterologous tachyzoites were 1 to 3 dilutions lower than to homologous tachyzoites. Sera from B. darlingi- or B. neotomofelis-infected cats did not react with tachyzoites of Toxoplasma gondii or Neospora caninum or merozoites of Sarcocystis neurona using the IFAT. Antibodies to B. darlingi were found in 14% and 2% of cats from Virginia and Pennsylvania, respectively. Antibodies to B. neotomofelis were found in 5% and 4% of cats from Virginia and Pennsylvania, respectively. Nine cats from Virginia and 1 cat from Pennsylvania were positive for both.

Prevalence of IgG antibodies to Encephalitozoon cuniculi and Toxoplasma gondii in cats with and without chronic kidney disease from Virginia.

Kidney disease is a common and serious condition in domestic cats. There are numerous causes of kidney disease including parasitic infection. Encephalitozoon cuniculi is a microsporidian parasite that develops in the kidneys of rabbits and causes chronic renal disease. Little has been reported concerning E. cuniculi in cats and no serological studies on this parasite in cats have been conducted in the United States to date. The present study explored the possibility that E. cuniculi is an unrecognized contributor to the high prevalence of kidney disease observed in cats. A serological survey was conducted to determine the prevalence of IgG antibodies to spores of E. cuniculi in cats with and without a diagnosis of chronic kidney disease (CKD) according to the International Renal Interest Society (IRIS) staging system. Likewise, samples were examined for IgG antibodies to Toxoplasma gondii, a common well studied protozoan of cats. Plasma and sera were obtained from 232 feline patients at the Virginia-Maryland Regional College of Veterinary Medicine teaching hospital. With the investigators blinded to the renal status of test subjects, samples were screened via indirect immunofluorescent antibody assay (IFA). Thirty-six of the 232 cats met the IRIS staging system criteria for CKD. Antibodies to E. cuniculi were found in 15 of the 232 samples, which included 4 of the 36 cats with CKD. Sera from cats serologically positive to E. cuniculi did not react to spores of E. intestinalis or E. hellem when examined in the IFA. Antibodies to T. gondii were found in 63 of the 232 samples, which included 10 of the 36 cats with CKD. The prevalence of antibodies in cats with CKD to either protozoan was not significantly different (P>0.05) from the cats without CKD in the study. Collectively the results do not support the hypothesis that either E. cuniculi or T. gondii play a significant etiologic role in the occurrence or progression of CKD in cats.

Prevalence of antibodies to Sarcocystis neurona in cats from Virginia and Pennsylvania.

Sarcocystis neurona is best known as the causative agent of equine protozoal myeloencephalitis of horses in the Americas. Domestic cats ( Felis domesticus ) were the first animals described as an intermediate host for S. neurona . However, S. neurona -associated encephalitis has also been reported in naturally infected cats in the United States. Thus, cats can be implicated in the life cycle of S. neurona as natural intermediate hosts. The present study examined the seroprevalence of IgG antibodies to merozoites of S. neurona in populations of domestic cats from Virginia and Pennsylvania. Overall, sera or plasma from 441 cats (Virginia = 232, Pennsylvania = 209) were tested by an indirect immunofluorescent assay at a 1ratio50 dilution. Antibodies to S. neurona were found in 32 (7%) of 441 cats. Of these, 22 (9%) of the 232 cats from Virginia and 10 (5%) of the 209 cats from Pennsylvania were seropositive for S. neurona .

Frequency of incomplete urolith removal, complications, and diagnostic imaging following cystotomy for removal of uroliths from the lower urinary tract in dogs: 128 cases (1994-2006).

OBJECTIVE: To determine the effectiveness of cystotomy for complete removal of urocystoliths and urethroliths in dogs, the types and frequency of diagnostic imaging performed to verify complete urolith removal, the complications that develop as a result of cystotomy, and predictors of each of these variables. DESIGN: Retrospective case series. ANIMALS: 128 dogs that underwent a cystotomy for removal of urocystoliths, urethroliths, or both from 1994 through 2006. PROCEDURES: The following data were obtained from medical records: sex, body weight, number and locations of lower urinary tract uroliths identified in preoperative and postoperative imaging reports, types of imaging used for urolith detection, number of uroliths recovered during cystotomy, quantitative urolith composition, and major complications attributable to cystotomy. Objective criteria were applied to determine whether a cystotomy failed or succeeded and whether appropriate imaging was performed. Associations between potential prognostic factors and outcomes were statistically assessed. RESULTS: Effectiveness of cystotomy could be determined in 44 (34%) dogs, of which 9 (20%) had incomplete removal of uroliths. Appropriate postoperative imaging was performed for only 19 (15%) dogs, of which 8 had incomplete removal. Dogs with both urethroliths and urocystoliths were more likely to have a failed cystotomy than dogs with only urethroliths or urocystoliths. Complications developed in 5 (4%) dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Cystotomy was a safe and effective surgical procedure for removal of lower urinary tract uroliths in most dogs. Failure to remove all uroliths occurred in a substantial percentage of patients.

Effect of water source on intake and urine concentration in healthy cats.

Increasing water intake and decreasing urine concentration are recommended for cats with urolithiasis and with idiopathic cystitis. Fountains are advocated to encourage drinking; however, effects on drinking of fountains have not been reported in cats living in pet owners homes. Thirteen healthy cats were assigned to have 24-h water intake and urine osmolality and specific gravity measured when water was offered from a bowl or fountain. One cat developed excessive barbering, vomiting, and refusal to drink water offered from the fountain. For the remaining 12 cats, intake was slightly greater from the fountain. However, urine osmolality was not significantly different. In this study, a fountain failed to substantially increase water intake and dilute urine in cats. A similar study including a greater period of time and additional cats may clarify the results of this study.

Disseminated Geosmithia argillacea infection in a German shepherd dog.

We report a systemic mycosis in a German Shepherd dog caused by Geosmithia argillacea. Although this etiologic agent microscopically resembles a Penicillium species, and is histopathologically compatible with members of the genus Aspergillus, morphologic features and molecular characterization clearly separate it from these genera. This appears to be the first report of disseminated disease by this species in humans or animals. In vitro antifungal susceptibility testing suggests resistance to amphotericin B and voriconazole and susceptibility to caspofungin, itraconazole, and posaconazole.

Simultaneous analysis of vitamins and caffeine in energy drinks by surfactant-mediated matrix-assisted laser desorption/ionization.

As a new approach to rapid small-molecule analysis, surfactant-mediated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was successfully used in the analysis of caffeine and the vitamins riboflavin, nicotinamide, and pyridoxine in various energy drinks. Of five common MALDI matrices tested (alpha-cyano-4-hydroxycinnamic acid, sinapinic acid, 2,5-dihydroxybenzoic acid, dithranol, and 2',4',6'-trihydroxyacetophenone), alpha-cyano-4-hydroxycinnamic acid was found to be most suitable for analysis of high-sugar-containing energy drinks. Cetyltrimethylammonium bromide (CTAB) surfactant was used as a matrix-ion suppressor, at a matrix:surfactant mole ratio of approximately 500:1. The resulting mass spectra show very few matrix-related ions, while analyte signals were clearly observed. For comparative purposes the same analytes were identified and quantified in energy drinks by LC-ESI-MS with UV detection. Quantitatively the calibration curves of all four analytes showed a marked improvement when the surfactant-mediated method was used compared with traditional MALDI-TOF-MS; correlation coefficients of 0.989 (nicotinamide), 0.991 (pyridoxine), 0.983 (caffeine) and 0.987 (riboflavin) were obtained. It was found that in quantitation of the energy drink analytes the surfactant-mediated MALDI-TOF-MS results were comparable with those from LC analysis. In reproducibility experiments RSD values ranged from 9.7 to 18.1%. The work has demonstrated that this mass spectrometric approach can be used as a rapid screening technique for fortified drinks.

Rapid screening of anthocyanins in berry samples by surfactant-mediated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Surfactant-mediated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been used for the identification of flavonoids from three berry extracts: lowbush blueberry (Vaccinium angustifolium), lingonberry (Vaccinium vitis-idaea), and blackberry (Rubus armeniacus). The addition of the surfactant led to suppression of matrix ions from both alpha-cyano-4-hydroxycinnamic acid (CHCA) and 2',4',6'-trihydroxyacetophenone (THAP). This is the first case of this method being successfully employed with a matrix other than CHCA. It was observed that CHCA led to a great deal of fragmentation of the sugar moiety from glycosides, whereas THAP produced more intact glycoside molecules, and thus leads to better characterization of the flavonoids in a berry sample. The flavonoids were characterized and quantified by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) with UV detection. Although MALDI-TOF-MS did not lead to the identification of as many flavonoids, it did enable us to identify many anthocyanin glycosides. Quantification was achieved and demonstrated that use of the THAP matrix can enable quantification of the intact glycosides with relative standard deviation (RSD) values of less than 10% with surfactant addition. These results are comparable with LC results. MALDI-TOF-MS with THAP matrix thus provided a rapid method for the qualitative screening of these compounds. It took only a few minutes, greatly reducing the analysis time from that in traditional LC/MS methods.