A growing bacterial colony in two dimensions as an active nematic.

How a single bacterium becomes a colony of many thousand cells is important in biomedicine and food safety. Much is known about the molecular and genetic bases of this process, but less about the underlying physical mechanisms. Here we study the growth of single-layer micro-colonies of rod-shaped Escherichia coli bacteria confined to just under the surface of soft agarose by a glass slide. Analysing this system as a liquid crystal, we find that growth-induced activity fragments the colony into microdomains of well-defined size, whilst the associated flow orients it tangentially at the boundary. Topological defect pairs with charges [Formula: see text] are produced at a constant rate, with the [Formula: see text] defects being propelled to the periphery. Theoretical modelling suggests that these phenomena have different physical origins from similar observations in other extensile active nematics, and a growing bacterial colony belongs to a new universality class, with features reminiscent of the expanding universe.

Particle-size effects in the formation of bicontinuous Pickering emulsions.

We demonstrate that the formation of bicontinuous emulsions stabilized by interfacial particles (bijels) is more robust when nanoparticles rather than microparticles are used. Emulsification via spinodal demixing in the presence of nearly neutrally wetting particles is induced by rapid heating. Using confocal microscopy, we show that nanospheres allow successful bijel formation at heating rates two orders of magnitude slower than is possible with microspheres. In order to explain our results, we introduce the concept of mechanical leeway, i.e., nanoparticles benefit from a smaller driving force towards disruptive curvature. Finally, we suggest that leeway mechanisms may benefit any formulation in which challenges arise due to tight restrictions on a pivotal parameter, but where the restrictions can be relaxed by rationally changing the value of a more accessible parameter.

Dodecafluoropentane Emulsion Extends Window for tPA Therapy in a Rabbit Stroke Model.

Dodecafluoropentane emulsion (DDFPe) nanodroplets are exceptional oxygen transporters and can protect ischemic brain in stroke models 24 h without reperfusion. Current stroke therapy usually fails to reach patients because of delays following stroke onset. We tested using DDFPe to extend the time window for tissue plasminogen activator (tPA). Longer treatment windows will allow more patients more complete stroke recovery. We test DDFPe to safely extend the time window for tPA thrombolysis to 9 h after stroke. With IACUC approval, randomized New Zealand white rabbits (3.4-4.7 kg, n = 30) received angiography and 4-mm blood clot in the internal carotid artery for flow-directed middle cerebral artery occlusion. Seven failed and were discarded. Groups were IV tPA (n = 11), DDFPe + tPA (n = 7), and no therapy controls (n = 5). DDFPe (0.3 ml/kg, 2 % emulsion) IV dosing began at 1 h and continued at 90 min intervals for 6 doses in one test group; the other received saline injections. Both got standard IV tPA (0.9 mg/kg) therapy starting 9 h post stroke. At 24 h, neurological assessment scores (NAS, 0-18) were determined. Following brain removal percent stroke volume (%SV) was measured. Outcomes were compared with Kruskal-Wallis analysis. For NAS, DDFPe + tPA was improved overall, p = 0.0015, and vs. tPA alone, p = 0.0052. For %SV, DDFPe + tPA was improved overall, p = 0.0003 and vs. tPA alone, p = 0.0018. NAS controls and tPA alone were not different but %SV was, p = 0.0078. With delayed reperfusion, DDFPe + tPA was more effective than tPA alone in preserving functioning brain after stroke. DDFPe significantly extends the time window for tPA therapy.

Dodecafluoropentane emulsion delays and reduces MRI markers of infarction in a rat stroke model: a preliminary report.

BACKGROUND: Dodecafluoropentane emulsion (DDFPe), an oxygen transport agent, has been shown to reduce infarct volume in animal models of acute ischemic stroke (AIS). Our study assesses the effect of DDFPe on MRI markers of infarct evolution in the early hours after vascular occlusion in a rat AIS model. We hypothesized that DDFPe will delay the development of MRI markers of AIS and/or reduce the extent of infarction. METHODS: Permanent, unilateral surgical occlusion of the middle cerebral and common carotid arteries was performed in control (n=4) and treatment (n = 10) rats. The treatment group received 1 IV dose of 2% w/v DDFPe at 0.6 mL/kg at 1 hour post-occlusion versus none. Diffusion-weighted (DWI) and inversion recovery (IR) MRI sequences were obtained over the 4 hours following occlusion. Infarct extent was quantified by number of abnormal MRI slices per sequence for each group and time point. Student's T-test was applied. RESULTS: DDFPe-treated rats demonstrated reduced infarct extent versus controls over combined time points on IR at 5.43 ± 0.40 (mean ± standard error) abnormal slices vs. 7.38 ± 0.58 (P = 0.01) and on DWI at 5.21 ± 0.54 vs. 9.00 ± 0.95 (P < 0.01). Development of abnormal MRI signal was delayed in the treatment group. CONCLUSIONS: DDFPe delays and reduces MRI markers of AIS in the early hours following vascular occlusion in a rat stroke model. Further investigation of DDFPe as a neuroprotectant is warranted.

Dodecafluoropentane Emulsion (DDFPe) Decreases Stroke Size and Improves Neurological Scores in a Permanent Occlusion Rat Stroke Model.

BACKGROUND: Dodecafluoropentane emulsion (DDFPe), given IV one hour after stroke, has been shown to greatly reduce the percent stroke volume (%SV) in rabbits. With repeated doses its effect continued for 24 hours. PURPOSE: Test DDFPe as neuroprotective agent in permanent occlusion rat stroke models in Sprague Dawley (SD) and Spontaneously Hypertensive Rats (SHR) measuring both %SV and neurological assessment scores (NAS). METHODS: The male rats received either saline (control), or one or four doses (1x or 4x) of DDFPe (0.6ml/kg IV) one hour post stroke. Treatment groups were SD (n=26) (control, 1x and 4x; n=12, 7 and 7) and SHR (n=14) (control, 1x and 4x; n=7, 3 and 4). The 4x doses were given at 1.5 hour intervals. At six hours post stroke, the rats received a NAS using standard tests for balance, reflexes, and motor performance. Then rats were euthanized and brains removed for TTC evaluation of %SV. RESULTS: For %SV analysis strain differences were not significant therefore strains were combined. DDFPe significantly decreased %SV in 1x and 4xDDFPe groups compared to control groups (2.59±1.81 and 0.98±0.88 vs. 9.24±6.06, p≤0.001 each; p≤0.0001 for the overall test for treatment effect). The 1x versus 4xDDFPe groups were not significantly different (p=0.40). In NAS analysis both strains showed significant improvement with 4xDDFPe therapy vs. controls, (SD: 5.00+2.45 vs. 9.36+3.56, p=0.01; SHR: 7.75+4.43 vs. 12.14+3.08, p=0.05). Differences between the 1x DDFPe group and controls were not significant (SD: 8.43+3.69; SHR: 9. 33+3.51). CONCLUSION: DDFPe treatment provides significant neuroprotection when assessed six hours post stroke.

Progress in dodecafluoropentane emulsion as a neuroprotective agent in a rabbit stroke model.

Dodecafluoropentane emulsion (DDFPe) in 250 nm nanodroplets seems to swell modestly to accept and carry large amounts of oxygen in the body at >29 °C. Small particle size allows oxygen delivery even into hypoxic tissue unreachable by erythrocytes. Using permanent cerebral embolic occlusion in rabbits, we assessed DDFPe dose response as a neuroprotectant at 7 and 24 h post-embolization without lysis of arterial obstructions and investigated blood pharmacokinetics. New Zealand White rabbits (N = 56) received cerebral angiography and embolic spheres (diameter = 700-900 µm) occluded middle and/or anterior cerebral arteries. Intravenous DDFPe dosing (2 % w/v emulsion) began at 60 min and repeated every 90 min until sacrifice at 7 or 24 h post-embolization. Seven-hour groups: (1) control (embolized without treatment, N = 6), and DDFPe treatment: (2) 0.1 ml/kg (N = 7), (3) 0.3 ml/kg (N = 9), (4) 0.6 ml/kg (N = 8). Twenty-four-hour groups: (5) control (N = 16), and DDFPe treatment: (6) 0.1 ml/kg (N = 10). Infarcts as percent of total brain volume were determined using vital stains on brain sections. Other alert normal rabbits (N = 8) received IV doses followed by rapid arterial blood sampling and GC-MS analysis. Percent infarct volume means significantly decreased for all DDFPe-treated groups compared with controls, p = <0.004 to <0.03. Blood DDFP (gas) half-life was 1.45 ± 0.17 min with R = 0.958. Mean blood clearance was 78.5 ± 24.9 ml/min/kg (mean ± SE). Intravenous DDFPe decreases ischemic stroke infarct volumes. Blood half-life values are very short. The much longer therapeutic effect, >90 min, suggests multiple compartments. Lowest effective dose and maximum effective therapy duration are not yet defined. Rapid development is warranted.

Successful intravascular ultrasound thrombolysis of dural sinus thrombosis with pre-existing subarachnoid and intraparenchymal hemorrhages.

A case of cerebral venous thrombosis with intraparenchymal and subarachnoid hemorrhages was initially treated unsuccessfully with mechanical and pharmacologic thrombolysis using intrathrombus tissue plasminogen activator (tPA) and angioplasty, and later successfully treated with an intravascular ultrasound tPA infusion catheter. This new microcatheter allowed direct infusion of tPA while using local therapeutic intravascular ultrasound to increase the thrombolytic effect. Flow was quickly restored. Our patient recovered from coma to discharge home without worsening of existing hemorrhages.

Measuring apathy after traumatic brain injury: Psychometric properties of the Apathy Evaluation Scale and the Frontal Systems Behavior Scale.

OBJECTIVES: To evaluate the reliability and validity of the Apathy Evaluation Scale (AES) and Apathy sub-scale of the Frontal Systems Behavior Scale (FrSBe-A) for people with traumatic brain injury (TBI). To identify an optimal cut-off score indicating presence of apathy according to the AES. METHODS AND PROCEDURES: A sample of 34 participants with severe TBI currently residing in the community underwent neuropsychological and psychosocial assessment to evaluate reliability, discriminant, convergent and divergent validity. Receiver Operating Characteristic (ROC) curve analysis was undertaken to identify an optimal cut-off score on the AES. RESULTS: AES and FrSBe-A correlated moderately with each other (r = 0.71). Both AES and FrSBe-A have good internal consistency and discriminant validity with measures of depression and fatigue. Support for hypothesized correlations with similar and dissimilar constructs was not shown. ROC analysis identified a cut-off score of 37 or higher on AES indicated presence of apathy. CONCLUSIONS: AES and FrSBe-A are reliable and valid measures of apathy following TBI. It is suggested that the two scales measure slightly differing aspects of the apathy construct, with AES addressing emotional-affective aspects of apathy more than FrSBe-A, which focuses more heavily on cognitive and behavioral elements of goal-directed behavior.

Apathy after acquired brain impairment: a systematic review of non-pharmacological interventions.

Apathy commonly occurs after acquired brain impairment. It is characterised by impaired initiative, diminished activity, and lack of concern; formally delineated as a decrease in cognitive, behavioural and emotional components of goal-directed activity. The impact is widespread, hampering rehabilitation and outcome. This systematic review identifies and assesses the efficacy of non-pharmacological treatments for apathy following four types of acquired brain impairment (traumatic brain injury, dementia, cerebrovascular accident, encephalitis). Nine databases were searched. Studies were reviewed according to the following criteria: age over 16 years, acquired brain impairment, non-pharmacological intervention for apathy, and data reported on treatment efficacy. The methodological quality of the studies was assessed. Searches yielded 1754 articles, with 28 meeting criteria. Methodological quality ranged greatly. The majority of trials involved the dementia population. Cognitive interventions were the most frequent mode of treatment. For those with severe impairments, the strongest evidence suggested music therapy and for milder impairment, the strongest evidence was for cognitive rehabilitation. This review reveals a need for more high quality, methodologically rigorous treatment studies for apathy, particularly within the milder ranges of impairment. Initially, however, a uniform operational definition needs to be utilised in all research studies to minimise variability. Additionally, employing a standardised outcome measure specific to apathy would greatly enhance comparison among treatments.

A multicentre, randomised trial examining the effect of test procedures measuring emergence from post-traumatic amnesia.

BACKGROUND: Post-traumatic amnesia (PTA) tests that record different PTA durations in the same patient, thereby raising measurement accuracy issues, have been reported previously. A major problem lies in determining the end point of PTA. AIMS: To delineate areas of discrepancy in PTA tests and to provide independent verification for a criterion signalling emergence from PTA. METHODS: In a randomised design, two related PTA procedures were compared, one purportedly more difficult (Westmead PTA Scale, WPTAS) than the other (Modified Oxford PTA Scale, MOPTAS). Eighty two patients in the early stages of PTA were examined daily until emergence, by using the Galveston Orientation and Amnesia Test (GOAT) and the WPTAS/MOPTAS. A short battery of cognitive and behavioural measurements was made on three occasions: at the early stage of PTA (time 1), towards the end of PTA when the maximum score (12/12) was first obtained (time 2) and at the traditional criterion for emergence (scoring 12/12 for 3 consecutive days; time 3). RESULTS: No significant difference was recorded in PTA duration between the MOPTAS and WPTAS. Both scales recorded longer PTA durations than the GOAT. By using Kaplan-Meier survival analyses, the WPTAS was found to show a more protracted pattern of emergence at the end stage of PTA than the MOPTAS. A time lag of > or = 1 week in the resolution of disorientation as compared with amnesia was observed in 59% cases. Significant improvements occurred on all independent measurements between time 1 and time 2, but on only 2 of 5 cognitive measurements between time 2 and time 3. CONCLUSIONS: Although no significant differences in the duration of PTA on the MOPTAS/WPTAS were recorded, emergence from the late stages of PTA occurred more promptly with the MOPTAS. The need for inclusion of both orientation and memory items in PTA tests is highlighted by the frequency of disorientation-amnesia dissociations. The patterns of results on the independent measures suggest that patients who are in PTA for > 4 weeks have probably emerged from PTA when they first score 12/12 on the MOPTAS/WPTAS, and this criterion can replace the traditional criterion.

Saratin, an inhibitor of von Willebrand factor-dependent platelet adhesion, decreases platelet aggregation and intimal hyperplasia in a rat carotid endarterectomy model.

PURPOSE: Post-carotid endarterectomy, thrombosis, and intimal hyperplasia may be decreased by the inhibition of platelet adhesion and activation. In this study, a novel agent, saratin, was used to inhibit platelet-to-collagen adhesion in a rat carotid endarterectomy model. Saratin is a recombinant protein isolated from the saliva of the medicinal leech Hirudo medicinalis, which is thought to act by binding to collagen, and inhibits von Willebrand factor-collagen interaction under conditions of increased shear and therefore, the adherence and activation of platelets at the vessel wall. Saratin has the advantage of being a nonsystemic, site-specific topical application. METHODS: A rat carotid endarterectomy model was used in which an open technique with arteriotomy and intimectomy was used. Saratin was applied to the endarterectomized surface of the carotid artery before arterial closure. End point measurements included platelet adhesion, thrombosis rate, intimal hyperplasia development, bleeding times, and platelet counts. Electron micrographs of carotid arteries were used for quantitative analysis of platelet aggregation and platelet counts. Intimal hyperplasia and thrombosis were assessed with computer-assisted morphometric analysis of elastin-stained carotid artery sections with direct measurement of the intimal hyperplasia area. RESULTS: The topical application of saratin significantly decreased platelet adhesion compared with controls at 3 hours after carotid endarterectomy (64 +/- 17 vs 155 +/- 33 platelets per grid, P = .05), and 24 hours after carotid endarterectomy (35 +/- 11 vs 149 +/- 37 platelets per grid, P = .0110), respectively. A percent luminal stenosis, as a measure of intimal hyperplasia, was significantly decreased with saratin application compared with controls (10.9% +/- 1.8% vs 29.8% +/- 6.8%, P = .0042). This decrease in intimal hyperplasia formation correlated with the inhibition of platelet adhesion. Thirty-three percent of control arteries were found to be thrombosed 2 weeks after carotid endarterectomy compared with a 0% thrombosis rate in the saratin-treated group (P = .0156). No increased bleeding was encountered along the arterial suture line in the saratin group. Bleeding times and systemic platelet counts were not found to change significantly in the saratin-treated rats compared with control rats at 3 and 24 hours after endarterectomy. CONCLUSION: Saratin significantly decreased platelet adhesion, intimal hyperplasia, luminal stenosis, and thrombosis after carotid endarterectomy in rats. Saratin did not increase suture line bleeding or bleeding times, and did not decrease platelet counts. Saratin may serve as a topical agent to be used for the site-specific inhibition of thrombosis and intimal hyperplasia after vascular manipulation.

Increased intimal hyperplasia after carotid endarterectomy in spontaneously hypertensive rats.

This study evaluated the effects of hypertension on postoperative intimal hyperplasia using a rat carotid endarterectomy (CEA) model with spontaneously hypertensive rats (SHR) and normotensive Sprague-Dawley rats (SD). SHR and SD rats underwent left carotid exposure and CEA via an arteriotomy, scoring and removal of the intima, followed by arteriotomy closure. The rats were then sacrificed two weeks postoperatively. The left carotid artery was harvested and underwent elastin and double immunohistochemical staining. The percent of lumenal stenosis was calculated using morphometric measurements, and stained cells within the intimal hyperplasia were counted. The means and standard deviation of the means were calculated, and the two groups were compared using a 2-sample t test. The systolic blood pressure was 228 +/-35 mm Hg in the SHR group and 108 +/-8 mm Hg in the SD group (p<0.00001). The percent of lumenal stenosis was 82.6 +/-17.1% in the SHR group and 21.2 +/-13.7% in the SD rats (p value <0.0001). The percentage of cells staining for a-SM actin was equal in the SHR group and the SD group (> 91%) but the percentage of these cells staining for BrdU was 38.2 +/-8.4% in the SHR group and 10.7 +/-5.8% in the SD group (p< 0.00001). Hypertension in the SHR rats was associated with an increased lumenal stenosis due to increased intimal hyperplasia. The increased intimal hyperplasia was due to enhanced and accelerated replication of smooth muscle cells. Hypertension may be associated with increased restenosis rates after CEA.

Blood S-adenosylmethionine concentrations and lymphocyte methylenetetrahydrofolate reductase activity in diabetes mellitus and diabetic nephropathy.

The erythrocyte concentrations of the body's chief physiologic methyl donor S-adenosylmethionine (SAM) and of its metabolite and inhibitor S-adenosylhomocysteine (SAH), the plasma concentrations of total homocysteine (tHcy), and the activity of N(5,10) methylenetetrahydrofolate reductase (MTHFR) in lymphocytes were determined in healthy subjects and patients with diabetes mellitus without complications and at various stages of diabetic nephropathy, categorized according to the degree of progression of the disease. These groups were as follows: 1, control; 2, diabetics with no complications; 3, patients with albuminuria; 4, patients with an elevated plasma creatinine; and 5, patients on dialysis. No parameter studied exhibited significant differences between the type 1 and the type 2 diabetics. In control subjects, the blood concentrations of SAM were proportional to the activity of MTHFR; in diabetics, it was not. Consistent with previous observations, progression of nephropathy was accompanied by increased concentrations of tHcy. Increased erythrocyte concentrations of SAH, decreased erythrocyte concentrations of SAM, SAM/SAH ratios, and lymphocyte MTHFR activity also accompanied disease progression. The blood concentrations of SAH paralleled those of tHcy, while the concentrations of SAM showed a bimodal relationship with those of tHcy. These results provide further evidence that alterations in the blood concentrations of SAM and related compounds are abnormal in patients with diabetes, particularly in those with nephropathy. The deficiency of SAM may lead to methyl deficiencies, which may contribute to the high morbidity and mortality in patients with diabetic nephropathy. We have also demonstrated a decrease in lymphocyte MTHFR activity in patients with advanced nephropathy, suggesting that hyperhomocysteinemia in these patients may be due to a generalized metabolic abnormality. Further studies are needed to determine the pathogenesis of these abnormalities and whether they are present in renal failure due to causes other than diabetes or whether they are specific to diabetic nephropathy.

Folate supplementation inhibits intimal hyperplasia induced by a high-homocysteine diet in a rat carotid endarterectomy model.

OBJECTIVE: Hyperhomocysteinemia has been implicated as a causative factor in intimal hyperplasia development. The addition of dietary folate in a hyperhomocysteinemia, carotid endarterectomy rat model is postulated to decrease plasma homocysteine levels and, in turn, reduce post-carotid endarterectomy intimal hyperplasia. METHODS: Each rat was fed one of six diets: (1) lab chow with no folate (n = 7), (2) lab chow with 10 mg/kg folate added (n = 3), (3) lab chow with 25 mg/kg folate added (n = 3), (4) a homocysteine diet with no folate (n = 7), (5) a homocysteine diet with 10 mg/kg folate added (n = 5), or (6) homocysteine diet with 25 mg/kg folate added (n = 5). Each rat then underwent an open carotid endarterectomy. In 2 weeks, intimal hyperplasia in the carotid artery was measured. Plasma homocysteine and folate levels were measured. RESULTS: Plasma folate levels rose with folate administration. Plasma homocysteine in the lab chow group was 5.4 +/- 0.5 micromol/L and did not change with the addition of folate. In the homocysteine diet group, plasma homocysteine rose 10-fold over the lab chow group (51.9 +/- 6.5 vs 5.4 +/- 0.5, micromol/L, P <.0001). In the group fed a homocysteine diet with 10 mg/kg folate added, a significant decrease in plasma homocysteine was observed (17.5 +/- 8.5 vs 51.9 +/- 6.5, micromol/L, P =.0003). In the group fed a homocysteine diet with 25 mg/kg folate added, plasma homocysteine levels were further reduced to levels seen in the lab chow group (12.6 +/- 2.6 vs 5.4 +/- 0.5, micromol/L, P = not significant). The relationship between plasma folate and homocysteine was inverse (R = 0.39, P =.0036). Luminal stenosis due to intimal hyperplasia was minimal in lab chow groups and unaffected by folate. The homocysteine diet group demonstrated post-carotid endarterectomy luminal stenosis due to intimal hyperplasia (60.9% +/- 9.2%). In the group fed a homocysteine diet with 10 mg/kg folate added, intimal hyperplasia was reduced, compared with the homocysteine diet group (32.6% +/- 7.4% vs 60.9% +/- 9.2%, P =.009). In the group fed a homocysteine diet with 25 mg/kg folate added, intimal hyperplasia was reduced to lab chow group levels (10.8% +/- 0.8% vs 4.8% +/- 1.0%, P = not significant) and was reduced, compared with the group fed a homocysteine diet with 10 mg/kg folate added. CONCLUSION: The use of folate in this hyperhomocysteinemia carotid endarterectomy model and the resultant attenuation of plasma homocysteine elevation and intimal hyperplasia development lend strong support to homocysteine being an independent etiologic factor in post-carotid endarterectomy intimal hyperplasia.

Increasing levels of dietary homocystine with carotid endarterectomy produced proportionate increases in plasma homocysteine and intimal hyperplasia.

PURPOSE: The role that homocysteine may play in post-carotid endarterectomy (CEA) restenosis due to intimal hyperplasia is not well understood. This study was designed to investigate the effects of different levels of dietary homocystine on: (1) plasma homocysteine; (2) post-CEA intimal hyperplasia; and (3) levels of the methyl donor S-adenosylmethionine (SAM) and its counterpart S-adenosylhomocysteine (SAH) in the homocysteine pathway. METHODS: Male rats were fed specialized diets for 2 weeks pre- and post-CEA. Groups included control (0 homocystine added, n=9), 1.5 (1.5 g/kg homocystine added, n=10), 3.0 (3.0 g/kg homocystine added, n=9), and 4.5 (4.5 g/kg homocystine added, n=11). The rats underwent a surgical carotid endarterectomy. Endpoints included; plasma homocysteine, intimal hyperplasia, replicative index using with alpha-SM actin and BrdU, hepatic SAM levels, SAH levels, and the hepatic activities of methylenetetrahydrofolate reductase (MTHFR) and cystathionine beta-synthase (CBS). RESULTS: Increasing dietary homocystine produced a proportionate increase in plasma homocysteine and an increase in intimal hyperplasia. Regression analysis of plasma homocysteine levels and intimal hyperplasia showed a significant correlation (r=0.71,P=0.003). Plasma homocysteine levels above 15 microM were associated with significant increases in intimal hyperplasia above 6.5% (P=0.04). Elevation of plasma homocysteine levels to moderate levels (5-25 microM) resulted in significant post-CEA intimal hyperplasia. Cellular analysis of the area of intimal hyperplasia in all diet groups showed comparable amounts of cells positive for alpha-SM actin. However, with increasing levels of dietary homocystine and plasma homocysteine there was an increase in replicative index (P<0.001) as determined by BrdU staining. Increasing dietary homocystine increased plasma homocysteine and was followed by increases in the replicative index thus producing increased intimal hyperplasia and lumenal stenosis. In hepatic measurements the 1.5 and 3.0 g/kg homocystine diets caused: increased liver activity of MTHFR (P=0.03) and decreased hepatic levels of SAM, SAH and SAM/SAH ratios compared to controls. Homocystine treatment did not cause significant alterations in CBS levels (P=0.992). These studies also showed no correlation of the MTHFR and CBS enzymes with plasma homocysteine levels or intimal hyperplasia. However, hepatic levels of SAM showed significant negative correlations with plasma homocysteine (r=-0.58; P=0.006) and with BrdU percentages of cellular proliferation (r=-0.69; P=0.06). CONCLUSION: The degree of post-CEA intimal hyperplasia in a rat model is directly related to the plasma level of homocysteine. The hyperplastic effects of homocysteine may be mediated in part by a physiological insufficiency of methyl donors as shown by decreases in SAM. Thus, increasing levels of plasma homocysteine enhanced and accelerated the smooth muscle cell response after CEA which led to increased intimal hyperplasia and lumenal stenosis.

Comparative immunogenicity of two bivalent botulinum vaccines.

OBJECTIVE: To compare the ability of a new single-dose botulinum vaccine containing a non-mineral oil adjuvant with a single dose of a conventional botulinum vaccine product to produce antibody to Clostridium botulinum types C and D in cattle in Northern Australia. DESIGN AND PROCEDURE: One hundred and fifty Brahman steer weaners were randomly divided into two groups receiving either a single dose of CSL Bivalent Botulinum vaccine or Websters Singvac. Blood samples were collected at 0, 8 and 24 weeks and tested by antibody ELISA. The final samples were also tested by the toxin neutralisation test, to test titres of neutralising antibody. RESULTS: Six months after inoculation, cattle vaccinated with Websters Singvac had ELISA antibody response twice that of CSL conventional product. However, this difference was only evident for neutralising antibody to type C botulinum toxin. Both products produced similar titres of type D neutralising antibody after a single dose. CONCLUSION: Websters' Singvac produces a greater neutralising antibody response to type C botulism upon single inoculation than a conventional vaccine. The product produces an equivalent neutralising antibody response to type D.

Emergence of gram-negative bacilli in the mouths of bone marrow transplant recipients using chlorhexidine mouthrinse.

PURPOSE/OBJECTIVES: To examine whether use of chlorhexidine (CHX) in stomatitis-prevention regimens following bone marrow transplantation (BMT) enhances the emergence of gram-negative bacilli (GNB) to a degree that exceeds its benefits. DATA SOURCES: Articles, book chapters, and case studies. DATA SYNTHESIS: Despite rigorous topical and systemic antimicrobial therapy, oral opportunistic GNB infections occur following BMT. This is most likely because of low susceptibility of GNB to CHX and not that CHX predisposes patients to these infections or the development of CHX resistant strains. CONCLUSIONS: The benefits of CHX use (e.g. preservation of oral mucosa and broad-spectrum antibacterial and antifungal effects) outweight the risks of GNB infection. IMPLICATIONS FOR NURSING PRACTICE: Routine clinical and microbiologic monitoring of the oral cavity are essential with use of CHX. Stomatitis care standards and patient instructions following discharge are included.

A placebo-controlled model to assay the onset of action of nonprescription-strength analgesic drugs.

The definition and detection of the onset of analgesic drug activity represent two of the more complicated methodologic challenges in clinical pharmacology. We addressed these issues by designing an analgesic assay with frequent posttreatment assessments to identify the first time when a subject experienced relief and when a nonprescription-strength analgesic could be distinguished from placebo. To test the feasibility of conducting this assay, 29 subjects with acute sore throat were randomized to receive 200 mg ibuprofen, 400 mg ibuprofen, or placebo under double-blind conditions. To identify the onset of analgesia, subjects used three rating scales at 5-minute intervals over the first hour. Subjects completed each series of assessments efficiently, most within 5 seconds. Each active agent was differentiated from placebo early after treatment (p < or = 0.05), and there was dose-separation. We conclude that the sore throat pain model can be used to evaluate the onset of action of nonprescription-strength analgesic agents.

Clinical and microbiological effects of a sanguinaria-containing mouthrinse and dentifrice with and without fluoride during 6 months of use.

The purpose of this study was to test the efficacy and safety of sanguinaria-containing regimens with and without fluoride using the American Dental Association guidelines for evaluating chemotherapeutic agents. The study was a 6-month, double-blind, 4-cell, placebo-controlled, parallel investigation involving 120 subjects. Following screening procedures, subjects were randomly assigned to 4 groups. Group 1 received a dentifrice containing 0.075% sanguinaria extract (SaE) and 2.0% zinc chloride (ZnCl2) in a dicalcium phosphate base, plus an oral rinse containing 0.03% SaE and 0.2% ZnCl2. Group 2 received identical products without SaE or ZnCl2. Group 3 received a dentifrice containing 0.8% sodium monofluorophosphate, 0.075% SaE, and 0.05% ZnCl2 in a silica base, plus an oral rinse containing 0.03% SaE and 0.2% ZnCl2. Group 4 products were identical to those of Group 3 but without SaE and ZnCl2. Supragingival plaque and gingival inflammation were scored at 0, 1, 2, 1.5, 3, 4.5, and 6 months; bleeding upon probing was measured at 1, 1.5, 3, and 6 months. Microbiological samples were taken from plaque, tongue, and cheek areas. The active products produced statistically significantly lower scores than the placebo agents for all indices (P less than .0001). Six-month plaque scores were 13.1% lower for Group 1 and 17.4% lower for Group 3 compared to placebo products. When the Plaque Severity Index was applied, the percentage reductions were 33% for Group 1 and 41% for Group 3 compared to placebos. Gingival inflammation scores were 16.7% lower for Group 1 and 18.1% lower for Group 3 at 6 months compared to placebo scores.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral Candida albicans in bone marrow transplant patients given chlorhexidine rinses: occurrence and susceptibilities to the agent.

The tongue and buccal mucosa of 26 bone marrow transplant recipients given three 0.12% chlorhexidine digluconate (CHX) oral rinses daily for 8 weeks were sampled weekly for oral Candida albicans. Putative C. albicans colony-forming units on selective bismuth sulfite glucose glycine yeast agar plates were identified with the API 20C system. The CHX minimum inhibitory concentrations (MICs) of oral C. albicans isolates obtained at all 8 sample weeks was determined with a microbroth dilution sensitivity assay. The CHX MIC range for yeast isolates selected randomly at all sample weeks was up to 2.5 to up to 20 micrograms/ml (mean MIC less than or equal to 8.5 micrograms/ml). The CHX MIC range for isolates at week 1 was less than or equal to 5 to less than or equal to 10 micrograms/ml (mean MIC less than or equal to 7.9 micrograms/ml) compared with less than or equal to 2.5 to less than or equal to 20 micrograms/ml at week 8 (mean MIC less than or equal to 8.8 micrograms/ml). Therefore the persistence of oral C. albicans in bone marrow transplant recipients using CHX rinses was due neither to low CHX susceptibilities nor to the development of resistance to the agent.