Alternative fecal indicators and their empirical relationships with enteric viruses, Salmonella enterica, and Pseudomonas aeruginosa in surface waters of a tropical urban catchment.

The suitability of traditional microbial indicators (i.e., Escherichia coli and enterococci) has been challenged due to the lack of correlation with pathogens and evidence of possible regrowth in the natural environment. In this study, the relationships between alternative microbial indicators of potential human fecal contamination (Bacteroides thetaiotaomicron, Methanobrevibacter smithii, human polyomaviruses [HPyVs], and F+ and somatic coliphages) and pathogens (Salmonella spp., Pseudomonas aeruginosa, rotavirus, astrovirus, norovirus GI, norovirus GII, and adenovirus) were compared with those of traditional microbial indicators, as well as environmental parameters (temperature, conductivity, salinity, pH, dissolved oxygen, total organic carbon, total suspended solids, turbidity, total nitrogen, and total phosphorus). Water samples were collected from surface waters of urban catchments in Singapore. Salmonella and P. aeruginosa had significant positive correlations with most of the microbial indicators, especially E. coli and enterococci. Norovirus GII showed moderately strong positive correlations with most of the microbial indicators, except for HPyVs and coliphages. In general, high geometric means and significant correlations between human-specific markers and pathogens suggest the possibility of sewage contamination in some areas. The simultaneous detection of human-specific markers (i.e., B. thetaiotaomicron, M. smithii, and HPyVs) with E. coli and enterococcus supports the likelihood of recent fecal contamination, since the human-specific markers are unable to regrow in natural surface waters. Multiple-linear-regression results further confirm that the inclusion of M. smithii and HPyVs, together with traditional indicators, would better predict the occurrence of pathogens. Further study is needed to determine the applicability of such models to different geographical locations and environmental conditions.

Endovascular treatment of ruptured thoracic aortic aneurysm in patients older than 75 years.

OBJECTIVES: To investigate the outcomes of thoracic endovascular aortic repair (TEVAR) for ruptured descending thoracic aortic aneurysm (rDTAA) in patients older than 75 years. METHODS: We retrospectively identified all patients treated with TEVAR for rDTAA at seven referral centres between 2002 and 2009. The cohort was stratified according to age ≤75 and >75 years, and the outcomes after TEVAR were compared between both groups. RESULTS: Ninety-two patients were identified of which 73% (n = 67) were ≤75 years, and 27% (n = 25) were older than 75 years. The 30-day mortality was 32.0% in patients older than 75 years, and 13.4% in the remaining patients (p = 0.041). Patients older than 75 years suffered more frequently from postoperative stroke (24.0% vs. 1.5%, p = 0.001) and pulmonary complications (40.0% vs. 9.0%, p = 0.001). The aneurysm-related survival after 2 years was 52.1% for patients >75 years, and 83.9% for patients ≤75 years (p = 0.006). CONCLUSIONS: Endovascular treatment of rDTAA in patients older than 75 years is associated with an inferior outcome compared with patients younger than 75 years. However, the mortality and morbidity rates in patients above 75 years are still acceptable. These results may indicate that endovascular treatment for patients older than 75 years with rDTAA is worthwhile.

Alteration of thromboxane and prostacyclin levels in experimental spinal cord injury.

We measured levels of thromboxane B2 and 6-keto-PGF1 alpha in rabbit spinal cord and cat CSF after impact injury to spinal cord. Rabbit tissue thromboxane B2 levels increased more than 6-keto-PGF1 alpha. In cat, CSF thromboxane B2 was higher the first hour postinjury; CSF 6-keto-PGF1 alpha also increased, but less so. These results imply activation of arachidonic acid metabolism. The relatively greater increase of thromboxane B2 suggests that thromboxane-prostacyclin imbalance may contribute to post-traumatic ischemia.

Cluster analysis of the metastatic patterns of human immunodeficiency virus-associated Kaposi's sarcoma.

Kaposi's sarcoma (KS) is a pleomorphic spindle cell lesion whose incidence has markedly increased among patients infected with the human immunodeficiency virus (HIV), especially among those whose primary risk factor is homo/bisexual transmission. The question as to whether KS is even a true neoplasm still remains largely unsettled due to the body of epidemiologic and histologic evidence suggesting an infectious etiology of the lesion. Accordingly, very few studies have been published regarding systemic distribution or patterns of metastatic progression of the lesion. In the past, such studies have been primarily hampered by inadequate sampling of different tissue specimens and by the lack of a method whereby the data could be rationally interpreted. In the present study we have reviewed the clinical and pathologic features of 169 autopsied patients with either documented HIV infection or the acquired immunodeficiency syndrome, among whom 28 patients were found to have KS. Using cluster analysis, we constructed a novel data structure, called a "dendrogram," whereby patterns of metastasis could be examined. Our results show at least three patterns of metastasis of the lesions, predominantly involving the skin, upper gastrointestinal tract, or midgastrointestinal tract, within this cohort of autopsied patients. These three patterns suggest that there is no single pathogenetic mechanism in the acquisition and dissemination of HIV-associated KS.

Bioavailability and metabolism of cidofovir following topical administration to rabbits.

The bioavailability and metabolism of the antiviral nucleotide analog cidofovir (HPMPC) were examined in New Zealand white rabbits following topical administration to normal and abraded skin. Male rabbits (four per group) received 14C-cidofovir (100 microCi/kg) intravenously (1 mg/kg) as a solution or topically (2 mg/animal) as a 1% w/w gel containing hydroxyethylcellulose (HEC) with or without propylene glycol (PG). The same PG/HEC formulation was applied topically to an abraded skin site in a fourth group of animals. All radioactivity detected in plasma and skin was accounted for by cidofovir. Plasma concentrations of radioactivity declined multiexponentially following intravenous administration, with a terminal half-life of 5.4 h. For intact skin, the absolute bioavailabilities of the HEC and PG/HEC formulations were 0.2 and 2.1%, respectively. For abraded skin, the bioavailability for the PG/HEC gel was 41%. Radioactivity in kidneys was attributed to cidofovir ( > 95%) and cyclic HPMPC. Concentrations in kidney following topical administration of cidofovir to normal skin were < 4% of those following intravenous dosing. Topical application of cidofovir to intact skin led to negligible systemic exposure to the drug. The topical bioavailability and hence the flux of cidofovir through intact skin was enhanced by the presence of PG in the formulation. Abrasion of the skin removed the principal barrier to absorption and led to significant systemic exposure to cidofovir.

Effect of oral probenecid coadministration on the chronic toxicity and pharmacokinetics of intravenous cidofovir in cynomolgus monkeys.

In animals and humans, intravenous administration of the antiviral nucleotide analogue cidofovir results in a dose-limiting nephrotoxicity characterized by damage to the proximal tubular epithelial cells. Probenecid, a competitive inhibitor of organic anion transport in the proximal tubular epithelial cells, was evaluated for its effect on the chronic toxicity and pharmacokinetics of cidofovir. Cynomolgus monkeys (5/sex/group) received cidofovir for 52 consecutive weeks as a once weekly intravenous bolus injection at 0 (saline), 0.1, 0.5, or 2.5 mg/kg/dose alone or at 2.5 mg/kg/dose in combination with probenecid (30 mg/kg/dose via oral gavage 1 h prior to cidofovir administration). Cidofovir-associated histopathological changes were seen only in the kidneys, testes, and epididymides. Nephrotoxicity (mild to moderate cortical tubular epithelial cell karyomegaly, tubular dilation, basement membrane thickening) was present only in monkeys receiving 2.5 mg/kg/dose cidofovir without probenecid. The incidence and severity of testicular (hypo- and aspermatogenesis) and epididymal (severe oligo- and aspermia) changes were increased in monkeys administered cidofovir at 2.5 mg/kg/dose, either alone or in combination with oral probenecid. Renal drug clearance was decreased between Weeks 1 and 52 in the 2.5 mg/kg/dose groups and resulted in an increased systemic exposure to cidofovir (as measured by AUC) that was significantly greater in monkeys administered cidofovir alone (312% increase in males, 98% in females) than in those coadministered probenecid (32% increase in males, 3% in females). These results demonstrate that oral probenecid coadministration protects against the morphological evidence of nephrotoxicity and the accompanying decrease in renal clearance in monkeys receiving chronic intravenous cidofovir treatment.

Anesthesia influences the outcome from experimental spinal cord injury.

The effect of anesthesia upon the functional outcome after experimental spinal cord injury (SCI) was studied in 221 rats subjected to graded weight drop contusion in the thoracic cord. Neurologic function was assessed in a blinded fashion for one week after injury using a modification of the method of Tarlov. The post-mortem concentrations of serotonin and its metabolite were measured in injured and surrounding spinal tissues in a subset of animals in order to estimate the survival of descending long-tract axons. In initial studies using non-ventilated animals where body temperature was not controlled (n = 130), halothane anesthesia was associated with significantly better neurologic scores at all levels of injury (50, 100 and 250 g.cm) in comparison to pentobarbital. In a second experiment under these conditions (n = 53) the effect of halothane was observed after a 50 g.cm injury in comparison to both pentobarbital and nitrous oxide. Improved neurologic recovery was accompanied by the preservation of normal serotonin and metabolite concentrations in spinal tissue caudal to the site of injury. These values did not differ from those measured in sham-operated animals. Separate experiments (n = 12) revealed halothane's preservation of somatosensory-evoked responses during the early postinjury period in animals showing improved neurologic recovery. Subsequent experiments (n = 12) were performed to assess the effect of oxygen supplementation and the control of rectal temperature and a separate series of acute experiments (n = 14) examined arterial blood pressure responses to injury in halothane- and pentobarbital-anesthetized animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of vision on head stability and torques during voluntary pulls made by standing humans.

This study tested the hypothesis that vision would improve pitch-plane stabilization of the head by increasing how well neck muscle torque compensates for torques associated with body motion, in a task where standing human subjects made rapid voluntary pulls. Ten subjects performed abrupt horizontal pulls on a handle to two peak force targets, with the eyes open and closed. We evaluated head angular velocity with respect to space. Inverse dynamics were used to subdivide the torque acting on the head into gravito-interactive and muscle components. A torque compensation ratio was computed from those two components. Head angular velocity was lower and the compensation ratio was higher during pulls made with the eyes open, for both force targets. The data suggest that vision enhances head stability by increasing the effectiveness with which muscle torques oppose gravito-interactive torques during voluntary pulls made while standing.

Spinal cord glucose utilization after experimental spinal cord injury.

Metabolic alterations after experimental contusion injury of the spinal cord were evaluated by determining qualitative spinal cord glucose utilization (SCGU), SCGU was determined by the 2-deoxy-D-[14C] glucose technique. An increase in SCGU occurred at the site of maximal impact in the white matter after an injury causing paraparesis and in near trauma regions after an injury causing either paraparesis or paraplegia. These findings are most likely due to anaerobic glycolysis resulting from a reduction in blood flow that still allows delivery of substrate to tissue. Although an initial increase was observed at the site of maximal impact after a paraplegia-causing injury, SCGU in the white matter demonstrated a progressive deterioration by 4 and 8 hours after injury. A failure of substrate delivery resulting from ischemia is the most likely cause for this reduction in SCGU. The somatosensory evoked potential was found to be a very sensitive indicator of the remaining functional axons at the injury site.

The histopathology of experimental spinal cord trauma. The effect of systemic blood pressure.

The early sequential histopathological alterations following a concussive paraplegic injury to the posterior thoracic spinal cord in cats were studied. The lack of significant progression of hemorrhages over a 4-hour period after injury indicates that most hemorrhages probably occur within the first hour. The marked enhancement or retardation of hemorrhages in the post-injury period, when the blood pressure was increased or decreased, respectively, demonstrates the loss of autoregulation of spinal cord vasculature at the trauma site after a concussive paraplegic injury. Progressive edema formation was evident over a 4-hour period following injury, and it could be enhanced or retarded by elevation or reduction of the systemic blood pressure.

Intranasal bioavailability of insulin powder formulations: effect of permeation enhancer-to-protein ratio.

The intranasal administration of powder formulations containing insulin and the permeation enhancer sodium tauro-24,25-dihydrofusidate (STDHF) were investigated in the sheep model. Both the hypoglycemic response and the serum insulin levels increased as the mole ratio of STDHF to insulin was increased from 0 to 16.8. In vitro dissolution rates of the powders and the rapid tmax (approximately 5 min) observed after intranasal administration suggest that the absorption of insulin is not dissolution limited. The bioavailabilities (F) of the powder formulations ranged from 2.9 to 37.8%. In comparison, the F values for a solution formulation with a STDHF:insulin ratio of 8.4 administered as either drops or spray were 15.7 and 37.4%, respectively. The permeation enhancer STDHF increases mucosal permeability and reduces the average molecular weight of the insulin species.

Optimization of in vitro flux through hairless mouse skin of cidofovir, a potent nucleotide analog.

The in vitro flux (4-8 h) of cidofovir (1-[(S)-3-hydroxy-2-(phosphonomethoxy)propyl]cytosine) was measured across full-thickness hairless mouse skin to evaluate potential formulations for local treatment of herpes virus infections. The effects of propylene glycol, isopropyl alcohol, oleic acid, pH, and cidofovir concentration were examined. In addition, several prototype aqueous gel formulations were studied. Flux values (4-8 h) increased linearly with cidofovir concentration in both solution and gel formulations. Removal of the stratum comeum by tape stripping increased the flux by approximately 400-fold, whereas pH (4.5 versus 7) had little effect on flux. The presence of propylene glycol, isopropyl alcohol, or their combination did not significantly increase mean flux (p > or = 0.05). Pretreatment of the skin with oleic acid resulted in a significant enhancement of cidofovir flux (p < or = 0.01). From the measured flux values, the calculated concentration of cidofovir achievable in the viable epidemis from a 1% cidofovir gel formulation was approximately 14 micrograms/mL, which is comparable to the in vitro 50% inhibitory dose (ID50) values for herpes simplex viruses HSV-1 and HSV-2.

Oral formulations of adefovir dipivoxil: in vitro dissolution and in vivo bioavailability in dogs.

The effect of formulation on oral bioavailability of the antiviral nucleotide analogue adefovir from the prodrug adefovir dipivoxil was examined in beagle dogs. A suspension formulation of adefovir dipivoxil granules was administered to five fasted male beagle dogs (250 mg prodrug per dog; 135.7 mg-equiv of adefovir per dog). Tablets prepared from the same granulation (batch B94) were administered at 2 x 125 mg prodrug per dog. In addition, the same tablets were administered to dogs in the fed state or following pentagastrin pretreatment. Two further tablet batches (H94 and D501) with slight formulation changes were also evaluated in pentagastrin pretreated dogs (n = 5). Concentrations of adefovir in plasma were determined by HPLC following fluorescence derivatization. Tablet dissolution was examined at pH 2.0. One batch of adefovir dipivoxil tablets showed a 5-fold slower dissolution rate in vitro (B94 = H94 >> D501). Adefovir dipivoxil was completely converted to adefovir following oral absorption in dogs. The oral bioavailability of adefovir from the suspension was 35.0 +/- 8.9%. The oral bioavailability of adefovir from the tablet formulation was 34.7 +/- 10.3%, 37.2 +/- 4.5%, and 44.9 +/- 5.9% in fasted dogs, fed dogs and fasted dogs pretreated with pentagastrin, respectively. All three tablet batches had equivalent bioavailability in dogs. Oral bioavailability of adefovir from the prodrug in dogs (35-46%) was unaffected by formulation, food, or the acidic pH of the gastrointestinal tract. In vitro dissolution of adefovir dipivoxil tablets did not correlate with oral bioavailability. Oral bioavailability of adefovir dipivoxil appears to be limited by low permeability and biological conversion of the prodrug to adefovir.

p53, p16 and RB expression in adenosquamous and squamous cell carcinomas of the stomach.

The expression of p53, p16 and RB proteins and their clinicopathologic correlation were investigated in 15 cases of primary gastric adenosquamous carcinoma and 2 cases of squamous cell carcinoma of the stomach. The male to female ratio of the patients was 13:4 and the average age was 55.7 years. None of the cases was early gastric carcinoma, and none of the adenocarcinoma components were of the diffuse or signet ring cell types. Fourteen cases showed metastasis to regional lymph nodes and/or other organs at the time of surgery. The adenocarcinoma component was metastasized to lymph nodes in 12 cases, and both adenocarcinoma and squamous cell carcinoma components were metastasized in three cases. The altered expression of p53 correlated with the advanced stage, but did not correlate with the depth of invasion, lymph node metastasis or recurrence. The altered expression of p16 and RB proteins did not correlate with any of the above clinico-pathologic factors. Both the adenocarcinoma and squamous cell carcinoma components revealed an inverse correlation between the expression pattern of p16 and RB proteins (p < 0.05). This suggests that the two proteins share a role in the carcinogenesis of these tumors. The expression pattern of p53 proteins in the adenocarcinoma and squamous cell carcinoma components was exactly the same in all of the cases. The expression patterns of p16 and RB protein were also identical in most of the cases. The expression patterns of all three proteins in the metastatic lesions were also identical to those in the primary lesions. The fact that the alteration of the three tumor suppressor gene products shares the same pattern suggests that squamous and adenocarcinoma components in the stomach originate from the same or a genetically related clone.

Overexpression of the 67 kD laminin receptor correlates with the progression of gastric carcinoma.

This retrospective study was designed to investigate the relationship between overexpression of the 67 kD laminin receptor (67LR) using immunohistochemistry, and several clinicopathological parameters including overall survival in human gastric adenocarcinoma. We stained paraffin-embedded sections of 93 resected primary gastric adenocarcinomas using a polyclonal antibody specific for the 67LR as well as monoclonal antibodies for p53 protein, epidermal growth factor receptor, proliferating cell nuclear antigen, carcinoembryonic antigen and chromagranin. The results showed statistically significant correlations between overexpression of the 67LR and types of early or advanced gastric carcinoma (p < 0.001), depth of invasion (p < 0.001), WHO histopathologic classification (p < 0.001), stage (p = 0.001), expression of p53 protein (p = 0.019), expression of epidermal growth factor receptor (p < 0.001) and proliferating cell nuclear antigen labeling index (p = 0.002). A lower proportion of signet ring cells revealed a higher percentage of overexpression of 67LR in both early (p < 0.002) and advanced (p < 0.001) gastric carcinomas. Intestinal type adenocarcinoma (according to Lauren's classification) revealed a higher percentage of overexpression of the 67LR than the diffuse type in both early (p = 0.057) and advanced (p < 0.001) gastric carcinomas. The correlations between overexpression of the 67LR and lymph node metastasis were statistically significant (p < 0.07). Although the overexpression of the 67LR tended to correlate with lower survival rates, the correlation was not statistically significant due to the limited sample size. Our data revealed that overexpression of the 67LR is correlated with the progression of gastric carcinoma. The expression of the 67LR may be important as one of the steps which determines invasiveness during the progression of cancer.

Enhanced chemical stability of the intracellular prodrug, 1-[((S)-2-hydroxy-2-oxo-1,4,2-dioxaphosphorinan-5-yl)methyl]cytosine, relative to its parent compound, cidofovir.

Degradation kinetics of cyclic HPMPC (cHPMPC), 1-[((S)-2-hydroxy-2-oxo-1,4,2-dioxaphosphorinan-5-yl)methyl]cytosi ne, and its parent compound cidofovir (also known as HPMPC) were conducted in the pH range of 2-11 at 70 degrees C. cHPMPC manifested greater chemical stability than cidofovir, except under alkaline conditions (pH?9). Three degradation products-cidofovir, cyclic HPMPU and HPMPU-were identified for cHPMPC, and the product distribution was characterized via a stability-indicating HPLC assay. Cyclic HPMPU and HPMPU are the uracil analogs of cHPMPC and cidofovir, respectively, formed through a hydrolytic deamination pathway. The deamination and hydrolysis rate constants for cHPMPC under acidic conditions were derived from the degradation product curves. The deamination rate constants for cHPMPC were about 8-fold slower compared to that for cidofovir. The enhanced chemical stability for cHPMPC relative to cidofovir is attributed to the absence of intramolecular catalysis with cHPMPC.

Evaluation of a model that determines the stability limits of dynamic balance.

A recent model of balance control has revealed two types of boundaries describing stability limits for center of mass (CM) dynamics: torque boundaries and state boundaries. The purpose of this study was to determine if these boundaries correctly characterize empirical data. We analyzed 2367 trials from 10 subjects who recovered their balance after they voluntarily pulled on a handle. We hypothesized that if model predictions were valid, both types of boundaries should encompass the empirical trajectories. We also hypothesized that each trajectory's nearest distance to the torque boundaries (the torque safety margin) would be correlated with the center of pressure (COP) safety margin, defined as the COP's nearest distance to the edge of the feet. The results supported the accuracy of the model-derived boundaries, with torque boundaries encompassing 100% and state boundaries encompassing 99.8% of the trials. Moreover, torque safety margins were highly correlated with COP safety margins, supporting the use of COP safety margins for estimating relative stability in dynamic tasks where balance is maintained. The distributions of the trajectories also suggested that a safety margin-oriented control strategy might be a robust alternative to the hypothesis that the central nervous system strives to optimize motion. The distinctions among different safety margins are discussed.

Distribution and metabolism of intravitreal cidofovir and cyclic HPMPC in rabbits.

PURPOSE: This study was designed to evaluate the intraocular distribution and metabolism of the antiviral nucleotide analogs cidofovir and cyclic 1-[(S)-3-hydroxy-2-(phosphonomethoxy) propyl]cytosine (HPMPC) in New Zealand white rabbits following intravitreal administration. METHODS: Male rabbits received either 14C-cidofovir or 14C-cyclic HPMPC by intravitreal injection into both eyes (50 micrograms/eye, 11 microCi/eye). Two animals per group were sacrificed at 24, 48, 72 or 240 h post-dose. Ocular tissues, kidney and liver were oxidized to determine total radioactivity and metabolites were determined by HPLC. RESULTS: At 24 h post-dose, total radioactivity was 9.96 and 5.18 micrograms-equiv/g for cidofovir and cyclic HPMPC, respectively, in vitreous and 20.9 and 3.54 micrograms-equiv/g, respectively, in retina. Although the initial vitreal clearance was 2-fold faster for the cyclic analog, the estimated terminal elimination half-lives in vitreous (42 hr) and in retina (66-77 hr) were similar for both drugs. By 240 h post-dose, radioactivity in all ocular tissues was approximately ten-fold higher for cidofovir. Radioactivity in vitreous at 240 h after intravitreal dosing with either drug contained cidofovir, cyclic HPMPC and cidofovir-phosphocholine. CONCLUSIONS: The long retinal half-life observed presumably reflects formation of phosphorylated cidofovir within retinal cells. Cidofovir achieved a ten-fold higher level of phosphorylated drug in retina than cyclic HPMPC: Therefore, intravitreal cidofovir may be expected to suppress progression of retinitis for a longer period than an equivalent intravitreal dose of cyclic HPMPC: The intravitreal half-life of cidofovir was 20-fold longer than that of ganciclovir in the same animal model.

Quantitative and clinical measures of static standing balance in hemiparetic and normal subjects.

Static standing balance was compared in 10 subjects with hemiparesis resulting from a cerebrovascular accident (33-71 years of age), 10 young normal subjects (22-40 years of age), and 10 older normal subjects (48-78 years of age) using a quantitative maximal load test and a clinical evaluation. The maximal load test required subjects to maintain a standing position against static loads applied at the waist (sagittal and frontal planes). Maximal loads were recorded as a percentage of body weight at the point when subjects could no longer hold the initial standing position. Effects of mechanical and cognitive factors were minimized in the maximal load test. Hemiparetic subjects had significantly lower maximal loads and clinical balance scores than both normal subject groups. Maximal loads of the young and older normal subjects were comparable, but the older subjects had lower clinical scores than the young subjects. Low correlations between subjects' scores on the two tests imply that each test yielded different information about static balance. Implications of the study results for the evaluation and treatment of balance deficits in hemiparetic persons are discussed.

Gunshot wounds to the extremities in children and adolescents.

Thirty-seven patients from 8 months to 17 years of age were evaluated prospectively and retrospectively after sustaining gunshot wounds to the extremities. This review supports the belief that higher velocity weapons and shotgun-wound injuries cause greater morbidity, with increased length of hospital stay and increased cost of care. Late growth abnormalities were related to recognized initial physeal injury and not to unrecognized physeal injury. Immediate neurologic deficits usually resolved partially or fully, without surgical treatment.