Vacancy island creation and coalescence using automated scanning tunneling microscopy

We demonstrate that scanning tunneling microscope tip-surface crash events can be utilized as an efficient means for the creation of predefined island configurations for diffusion studies. Using this method, islands of varying size can be created and placed in close proximity, increasing the probability of initiating and observing coalescence events. Data obtained from crash initiated events on a Ag(111) surface are presented. Relaxation time exponents extracted from these data confirm that our method gives results consistent with previous, sputter-obtained island coalescence studies. We also describe an instrument-control routine developed for these measurements that utilizes commercial imaging and off-the-shelf automation software to automate the tracking of islands or other features by the microscope.

Compact sources as the origin of the soft γ-ray emission of the Milky Way

The Milky Way is known to be an abundant source of gamma-ray photons, now determined to be mainly diffuse in nature and resulting from interstellar processes. In the soft gamma-ray domain, point sources are expected to dominate, but the lack of sensitive high-resolution observations did not allow for a clear estimate of the contribution from such sources. Even the best imaging experiment revealed only a few point sources, accounting for about 50% of the total Galactic flux. Theoretical studies were unable to explain the remaining intense diffuse emission. Investigating the origin of the soft gamma-rays is therefore necessary to determine the dominant particle acceleration processes and to gain insights into the physical and chemical equilibrium of the interstellar medium. Here we report observations in the soft gamma-ray domain that reveal numerous compact sources. We show that these sources account for the entirety of the Milky Way's emission in soft gamma-rays, leaving at most a minor role for diffuse processes.

Differential expression and induction of two Drosophila cytochrome P450 genes near the Rst(2)DDT locus

Previous studies have shown that the major metabolic resistance locus in the insecticide-resistant Drosophila line Rst(2)DDT(Wisconsin) maps between the markers cn and vg on chromosome 2. Six cytochrome P450 genes exist in this region. We investigated the expression levels of these P450 genes in DDT-resistant and -susceptible fly lines. We report: (i) DDT resistance is significant (> 30-fold) and dominant, (ii) resistance is reduced by the cytochrome P450 inhibitor PBO, (iii) there is constitutive over-expression relative to susceptible flies of two genes encoding cytochrome P450 enzymes within the cn-vg region (CYP6G1 = 4.3-fold; CYP12D1 = 6.0-fold), and (iv) exposure to DDT results in an increased expression of only one of these two P450 genes (CYP12D1 > or = 6-fold above constitutive resistant fly baselines).

Extracorporeal photopheresis in Sézary syndrome: hematologic parameters as predictors of response

Data were analyzed from 23 patients with Sézary syndrome (defined by erythroderma, more than 10% circulating atypical mononuclear cells, and peripheral blood T-cell clone) undergoing monthly extracorporeal photopheresis as the sole therapy for up to 1 year. The cohort showed a significant reduction of skin scores during treatment (P =.001). Thirteen patients (57%) achieved a reduction in skin score greater than 25% from baseline at 3, 6, 9, or 12 months (responders). Reduction in skin score correlated with reduction in the Sézary cell count as a percentage of total white cell count (P =.03). Responders and nonresponders were compared. None of the measured parameters was significantly different between the 2 groups. It was assessed whether any of the baseline parameters predicted outcome. A higher baseline lymphocyte count was significantly associated with a decrease in skin score at 6 months (P <.05). A higher baseline Sézary cell count as a percentage of total white cell count predicted a subject was more likely to be a responder after 6 months of treatment (P =.021). No other parameters predicted responder status. These data show that the modest falls in CD4, CD8, and Sézary cell counts were seen in all patients and might have resulted from lymphocyte apoptosis. This mechanism could explain the more favorable response seen in patients with higher percentages of Sézary cells in the peripheral blood. Alternatively, minimum tumor burden might be required for the induction of a cytotoxic response. Analysis of tumor-specific cytotoxic T cells is needed to investigate these possibilities further.

Otitis externa in UK general practice: a survey using the UK General Practice Research Database

BACKGROUND

Otitis externa is a common clinical problem in general practice and yet there are remarkably few data available on the demographic characteristics of patients with this condition and the approaches used by general practitioners (GPs) in the United Kingdom (UK) to manage it.

AIM

To define the descriptive epidemiology of otitis externa in the general population, to describe the first-line drug treatment used by UK GPs, and to determine factors related to second disease episodes.

DESIGN OF STUDY

Epidemiological data survey.

SETTING

All cases of otitis externa occurring in 1997 in practices contributing data to the UK General Practice Research Database.

METHOD

Data were extracted on age, sex, date of episode of otitis externa, treatment prescribed, co-existing diagnoses of eczema and diabetes, referral to ear, nose, and throat departments and occurrence of subsequent episodes of disease. Arbitrarily a second episode of disease was defined as persistence if it occurred at 28 days or fewer after the first episode and recurrence if it occurred at more than 28 days after the first episode.

RESULTS

A diagnosis of otitis externa was common in all age groups and, except in the elderly, was more common in females than males. There was an increase in disease episodes at the end of the summer in all age groups except the 60 years and over group. In the majority of cases GPs prescribed ear drops (85%), but a significant proportion of patients were also prescribed oral antibiotics (21%). Referral to secondary care was uncommon (3%). Among patients prescribed ear-drop formulations, those containing both steroid and antibiotic or steroid alone were used most commonly and were associated with the lower rates of disease persistence but not recurrence. Among patients prescribed antibiotics, penicillins were prescribed most commonly. Disease persistence rates, and to a lesser extent disease recurrence rates, were higher in patients prescribed oral antibiotics.

CONCLUSION

Otitis externa is a common condition and GPs can expect to see an excess of cases at the end of the summer. Topical ear drops are the most common treatment used in the UK. Patients prescribed steroid or steroid/antibiotic combination ear drops have fewer subsequent consultations for otitis externa over the following 28 days.

The palliative effects of octreotide in cancer patients

Octreotide is an extremely useful compound for palliative care physicians. It appears to be active in a number of different pain states and may be given by the spinal and intraventricular route. Its actions in reducing gut motility and secretions make it a valuable adjunct in the management of inoperable bowel obstruction. The same actions make it a potent antidiarrheal agent. Octreotide will often succeed where other antidiarrheal agents fail. Its ability to reduce gut secretions has led to its use in the treatment of fistulae. It has also been proposed as a useful drug in the management of cachexia and ascites. Most of the existing evidence is based on small numbers of case reports and further larger trials are necessary.

The buccal fat pad flap in oral reconstruction

BACKGROUND

The aim of this study is to describe the surgical technique, indications, advantages, and possible complications of the buccal fat pad flap and to report our clinical experience with this flap for intraoral reconstruction after tumor removal.

METHODS

The flap has been used to reconstruct oral defects after tumor resection in 32 patients, who have been retrospectively analyzed.

RESULTS

Adequate closure of the defect was achieved during surgery in all cases. In one case, there was partial loss of the flap; this was treated conservatively. In five cases there was some retraction in the reconstructed area.

CONCLUSIONS

Buccal fat pad as a flap offers an adequate reconstructive option to be born in mind when reconstructing small to medium defects in the oral cavity. It is a simple and quick surgical technique with a low incidence of complications.