Injectability of silicone oil-based tamponade agents.

BACKGROUND/AIMS: High viscosity silicone oils are used as tamponade agents to increase the resistance to emulsification; however, this makes the oils more difficult to inject. Increasing the extensional viscosity is one way to reduce emulsification. This study aimed to evaluate how silicone oils with increased extensional viscosity behave in terms of their ease of injection. METHODS: The shear viscosity and the length of time taken to inject 9 ml of Siluron 1000, Siluron 2000, Siluron 5000, SiliconMate, a 56/44 w/w blend of Siluron 1000/Siluron 5000 (Blend A) and a 90/10 w/w blend of Siluron 1000/PDMS 423kDa molecular weight (Blend B) were examined. RESULTS: The shear viscosity of Siluron 1000, Siluron 2000 and Siluron 5000 were within the expected ranges. The shear viscosity of Blend A was 2283 mPa s, Blend B was 4710 mPa s and SiliconMate was 995.3 mPa s. Siluron 1000 and SiliconMate had the shortest injection times as expected due to their lower shear viscosities. Comparison of Siluron 2000 and Blend A demonstrated that Siluron 2000 was easier to inject. Similarly, Blend B was easier to inject than Siluron 5000. CONCLUSION: Silicone oil blends containing small percentages of a high molecular weight additive are easier to inject than single grade oils of the equivalent shear viscosity.

Effects of a nanoparticulate silica substrate on cell attachment of Candida albicans.

AIMS: To investigate the influence of silica nanoparticles on the attachment and growth of Candida albicans cells. METHODS AND RESULTS: Spherical silica nanoparticles with diameters of 4, 7, 14 or 21 nm were attached to tissue culture polystyrene by a polycationic binding layer using a simple deposition procedure. The modified surfaces were shown to reduce the attachment and growth of C. albicans cells by a range of different measurements including microscopy, staining cells and measuring the amount of dye taken up and total cell activity measured using a dye reduction assay. For those cells that did attach and grow, the nanoparticle-coated surface inhibited the yeast to hyphal transition that is induced in the presence of serum. The greatest effect was observed for 7 and 14 nm diameter silica particles and we propose that the mechanism for these effects are related to either the topography of the surface or the slow dissolution of the bound silica. CONCLUSIONS: The attachment and growth of C. albicans is reduced by surface modification with silica nanoparticles. SIGNIFICANCE AND IMPACT OF THE STUDY: The modification of surfaces by nanoparticulate coatings is a simple process that may have applications in reducing the prevalence of Candida sp. cells on medical devices thus, limiting the incidence of this pathogenic yeast in clinical environments.

The effect of silica nanoparticulate coatings on cellular response.

The current techniques used to create patterned materials at the nanometer scale such as electron beam lithography are restricted to patterning small areas, which can be expensive and time consuming. A simple, cost-effective approach has been developed to create a reproducible surface topography to influence the cellular response. In this study, the cellular response of murine fibroblasts to 7, 14 and 21 nm colloidal silica particles were investigated over one, three and seven days and up to seven weeks. The surface topography and wettability of the surfaces were also studied. The results confirmed that silica particles create a nanoscale topography, which initiates a distinctive cellular response affecting the morphology, adhesion and proliferation of the fibroblasts. The effect was evident up to seven weeks with no adverse effects on cell viability.

Relationship of N-acetyl-beta- glucosaminidase levels to seriousness of suicide attempts.

We hypothesized that levels of N-acetyl-beta-glucosaminidase (NAG) would differ between patients making serious versus nonserious suicide attempts. The levels of NAG from 11 patients hospitalized for serious suicide attempts were compared to 5 patients whose suicide attempts were not rated serious. There was a significant difference in the mean NAG levels of the serious suicide attempters and the nonserious attempters (23 versus 52; p = 0.01). NAG may be a marker for a biological variable that is associated with the seriousness of a suicide attempt.

How to select counsel and participate in your own defense. The defendant's perspective.

The successful defense of a medical malpractice case is a team effort between the defendant doctor and his or her attorney. However, the most common complaint voiced by physicians is the failure, real or perceived, of the selected attorney to keep them involved in the preparation of the case and its progress. To ameliorate this situation, the author explains how to participate in one's defense in a helpful and meaningful fashion.

An association of NAG levels and a mutation of the CCK gene in panic disorder patients.

Levels of the enzyme N-acetyl-beta-glucosaminidase (NAG) and a mutation of cholecystokinin (CCK) gene appear to be independently associated with panic disorder. We explored whether there was an association of NAG levels and a CCK mutation identified in a group of panic disorder patients. NAG was measured in 12 panic disorder patients who had a mutation of the CCK gene and 17 who did not. Urine for NAG was collected at baseline and after 3 and 6 weeks of treatment. NAG levels were lower at all three times in the patients that did not have the CCK mutation. The difference between the two groups was significant at week 6 (P < 0.02), and showed a trend toward a difference at baseline (P < 0.15).

Association of N-acetyl-beta-glucosaminidase levels with seriousness of suicide attempts.

We hypothesized that levels of N-acetyl-beta-glucosaminidase (NAG) would differ between patients making serious versus nonserious suicide attempts. The levels of NAG from 7 patients hospitalized for serious suicide attempts were compared to 3 patients whose suicide attempts were not rated serious. There was a significant difference in the mean NAG levels of the serious suicide attempters and the nonserious attempters, 25 versus 61; p = .036. Implications of this finding are discussed.

Closure of a bronchopleural fistula using decalcified human spongiosa and a fibrin sealant.

Bronchopleural fistulas associated with empyema can occur as a life-threatening sequelae after pulmonary resection, most frequently occurring after pneumonectomy. With the use of the flexible bronchoscope, the bronchopleural fistula of a 62-year-old critically ill woman was permanently sealed with a fibrin sealant and a small section of demineralized human spongiosa. Closure of bronchopleural fistulas with the application of fibrin sealant plus human spongiosa may offer a valuable addition to the armament of therapeutic alternatives.

Cognitive impairment in the euthymic phase of chronic unipolar depression.

Cognitive functioning in the nonsymptomatic phase and the long-term cognitive outcome of patients with mood disorders are both heuristic and important clinical issues in the study of mood disorders. Literature findings are inconsistent because of design confounds. We tried to address these issues while controlling for several confounds including age, education, gender differences in neurobehavioral functioning, and diagnosis. Nonsymptomatic patients with a history of chronic unipolar depression and bipolar affective disorder and healthy male individuals were administered neuropsychological tests to assess attention, visual-motor tracking, executive abilities, and immediate verbal memory. Subjects had comparable depression scores at the time of testing. Disease duration was 7.5 years (SD 5.1) for unipolar and 11 years (SD 7.3) for bipolar patients. Unipolar patients were more impaired than healthy normal comparison subjects on measures of visual-motor sequencing (Trail Making Test A, p < .05), executive function (Trail Making Test B, Stroop Test Color/Word Trial, p < .05), and immediate memory and attention (CERAD 1st trial, WAIS Digit Symbol subtest, p < .05). Differences between bipolar patients and normal comparison subjects did not reach significance in any of the selected measures. Male patients with a history of chronic unipolar disorder are at risk for cognitive impairment in the nonsymptomatic phase of their disease. Cognitive disturbance is the type seen with prefrontal dysfunction and may be assessed with standard neuropsychological assessments.

Preliminary confirmation of the proposed link between reward-dependence traits and norepinephrine.

The tridimensional theory of personality posits that traits belonging to a personality spectrum called 'reward dependence' are determined in part by the neurotransmitter norepinephrine (NE). We hypothesized that urinary levels of the NE metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) would be significantly correlated to the reward dependence score on the Tridimensional Personality Questionnaire (TPQ). Twenty-seven never psychiatrically ill subjects collected urine for MHPG measurements and completed the TPQ. There was a significant correlation between the reward dependence score and the level of MHPG. MHPG levels was not associated with the other two personality dimensions, novelty seeking and harm avoidance. This preliminary study supports the hypothesis that reward-dependence traits are in part determined by NE.

Diazepam versus alprazolam for the treatment of panic disorder.

BACKGROUND: Alprazolam has proven efficacy as a treatment for panic disorder, but the place of other benzodiazepines is less well established. METHOD: To compare the efficacy and tolerability of diazepam and alprazolam for the disorder, a placebo-controlled, double-blind trial was undertaken in two sites. Two hundred forty-one subjects with panic disorder or agoraphobia with panic attacks were randomly assigned to flexible doses of diazepam, alprazolam, or placebo for 8 weeks. RESULTS: At the end of the trial, over 60% of subjects taking either diazepam or alprazolam were at least moderately improved compared with less than 30% of those taking placebo. On all measures of efficacy, subjects taking diazepam and alprazolam showed an equally favorable response. Despite some sedation early in the trial, both drugs were tolerated well. More severely ill subjects responded less well to either benzodiazepine. CONCLUSION: The results indicate that diazepam is an effective alternative to alprazolam for the treatment of panic disorder.

Urinary levels of 3-methoxy-4-hydroxyphenylglycol predict symptom severity in selected patients with unipolar depression.

There are preliminary biological data that support the validity of subtyping depressed patients by family history into depressive spectrum disease (DSD) and non-DSD groups. We hypothesized that a relatively homogeneous group of depressed patients might show an association between symptom severity and the norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG). Twenty-four patients with non-DSD depression showed a relationship between urinary levels of MHPG and the severity of several depressive symptoms. There were no associations between MHPG and symptom severity for 38 DSD patients. This study provides additional support for the validity of family history approaches to subtyping depression. The data also suggest that norepinephrine may be involved in some way in the pathogenesis of symptoms in non-DSD depression.

Low levels of MHPG in depressive spectrum patients.

There is some preliminary laboratory support for the proposed classification of depressed patients into depressive spectrum disease (DSD) and non-DSD. This study explores whether there is a difference in the levels of the norepinephrine metabolite, MHPG, in DSD and non-DSD patients. MHPG levels from 38 DSD patients were compared with 24 non-DSD patients. After controlling for the influence of age and gender on MHPG, the DSD patients had MHPG levels that were lower than non-DSD patients; 1655 +/- 90 mg/day vs. 1965 +/- 174 mg/day, respectively; P = 0.05. This study provides additional laboratory support for the DSD subtype. Possible implications of this finding are discussed.

Association of levels of N-acetyl-beta-glucosaminidase with severity of psychiatric symptoms in panic disorder.

Urinary levels of N-acetyl-beta-glucosaminidase (NAG) were measured in 58 patients with panic disorder. NAG levels were found to be significantly related to the severity of 23 of 72 mood states, measured by the Profile of Mood States, which were grouped in three categories: hostility or irritability, sadness, and panic. A similar result was found in a previous study of bipolar patients. NAG levels were also related to scores on the Hamilton Rating Scale for Anxiety and the Sheehan Patient-Rated Anxiety Scale. It is speculated that NAG could be a marker for serotonin.

Do low levels of MHPG in depressive spectrum patients normalize after successful treatment?

Patients with depressive spectrum disorder (DSD) have low levels of the norepinephrine metabolite, MHPG. This study examines what happens to the low levels of MHPG following improvement of depressive symptoms. Sixteen depressed patients with a family history consistent with DSD showed no change in MHPG after 6 weeks of treatment. This was true for both treatment responders and nonresponders. The lack of change in low levels of MHPG suggests that reduced norepinephrine turnover is a biological trait of DSD patients. Implications of this finding are discussed.

Topical fumagillin in the treatment of microsporidial keratoconjunctivitis in AIDS.

OBJECTIVE: To report microsporidial keratoconjunctivitis in a patient infected with HIV who was treated with topical fumagillin. CASE SUMMARY: A 37-year-old white man who was experiencing redness, pain, irritation, decreased vision, and a foreign body sensation occurring in both eyes was referred to the ophthalmology clinic. The patient had a medical history significant for AIDS, Pneumocystis carinii pneumonia, and Cytomegalovirus retinitis. Conjunctival smears were taken and stained positive for the presence of Microsporidia. The patient was diagnosed with bilateral microsporidial keratoconjunctivitis and fumagillin therapy was initiated. After 5 days of therapy, the patient reported significant improvements characterized by a decrease in blurred vision with only slight blurring in the left eye, decrease in headache, and decreased foreign body sensation. The patient continued topical fumagillin therapy for more than 14 months, with only slight blurring in the left eye and no apparent ocular toxicity as a result of fumagillin therapy. DISCUSSION: Although rare in occurrence, increasing numbers of documented microsporidial infections are being reported in the medical literature, particularly in individuals who are seropositive for HIV. Clinicians need to be cognizant of microsporidial keratoconjunctivitis as another opportunistic infection in this patient population. CONCLUSIONS: Although a curative agent has yet to be discovered, fumagillin represents a safe, effective, low-cost, topical agent for the treatment of microsporidial keratoconjunctivitis.

Relationship of generalized anxiety symptoms to urinary 5-hydroxyindoleacetic acid and vanillylmandelic acid.

Urinary levels of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) and the norepinephrine metabolite vanillylmandelic acid (VMA) were measured in 45 patients with generalized anxiety disorder. Multiple regression analysis demonstrated that the severity of several anxiety symptoms was predicted by levels of 5-HIAA and VMA. These data are consistent with the proposal that serotonin and norepinephrine may be involved in the pathophysiology of anxiety.

Is carbamazepine associated with NAG elevations suggestive of renal disease?

Elevations of urinary N-acetyl-beta-glucosaminidase (NAG) were found in previous studies of epileptic patients using carbamazepine. Since NAG can be a sensitive indicator of urinary tract problems, it was postulated that carbamazepine could be causing urinary tract damage. To explore this issue further, 27 mood disorder patients who were taking carbamazepine were compared to 171 mood disorder patients who were not using carbamazepine. There were no significant differences in NAG levels between the two groups. A hypothesis is presented which states that the elevated NAG levels found in some seizure patients could be associated with abnormalities of serotonin metabolism.