High throughput detection of capillary stalling events with Bessel beam two-photon microscopy

Significance

Brief disruptions in capillary flow, commonly referred to as capillary "stalling," have gained interest recently for their potential role in disrupting cerebral blood flow and oxygen delivery. Approaches to studying this phenomenon have been hindered by limited volumetric imaging rates and cumbersome manual analysis. The ability to precisely and efficiently quantify the dynamics of these events will be key in understanding their potential role in stroke and neurodegenerative diseases, such as Alzheimer's disease.

Aim

Our study aimed to demonstrate that the fast volumetric imaging rates offered by Bessel beam two-photon microscopy combined with improved data analysis throughput allows for faster and more precise measurement of capillary stall dynamics.

Results

We found that while our analysis approach was unable to achieve full automation, we were able to cut analysis time in half while also finding stalling events that were missed in traditional blind manual analysis. The resulting data showed that our Bessel beam system was captured more stalling events compared to optical coherence tomography, particularly shorter stalling events. We then compare differences in stall dynamics between a young and old group of mice as well as a demonstrate changes in stalling before and after photothrombotic model of stroke. Finally, we also demonstrate the ability to monitor arteriole dynamics alongside stall dynamics.

Conclusions

Bessel beam two-photon microscopy combined with high throughput analysis is a powerful tool for studying capillary stalling due to its ability to monitor hundreds of capillaries simultaneously at high frame rates.

TrueNTH sexual recovery study protocol: a multi-institutional collaborative approach to developing and testing a web-based intervention for couples coping with the side-effects of prostate cancer treatment in a randomized controlled trial

BACKGROUND

Over half of men who receive treatment for prostate suffer from a range of sexual problems that affect negatively their sexual health, sexual intimacy with their partners and their quality of life. In clinical practice, however, care for the sexual side effects of treatment is often suboptimal or unavailable. The goal of the current study is to test a web-based intervention to support the recovery of sexual intimacy of prostate cancer survivors and their partners after treatment.

METHODS

The study team developed an interactive, web-based intervention, tailored to type of treatment received, relationship status (partnered/non-partnered) and sexual orientation. It consists of 10 modules, six follow the trajectory of the illness and four are theme based. They address sexual side effects, rehabilitation, psychological impacts and coaching for self-efficacy. Each includes a video to engage participants, psychoeducation and activities completed by participants on the web. Tailored strategies for identified concerns are sent by email after each module. Six of these modules will be tested in a randomized controlled trial and compared to usual care. Men with localized prostate cancer with partners will be recruited from five academic medical centers. These couples (N = 140) will be assessed prior to treatment, then 3 months and 6 months after treatment. The primary outcome will be the survivors' and partners' Global Satisfaction with Sex Life, assessed by a Patient Reported Outcome Measure Information Systems (PROMIS) measure. Secondary outcomes will include interest in sex, sexual activity, use of sexual aids, dyadic coping, knowledge about sexual recovery, grief about the loss of sexual function, and quality of life. The impact of the intervention on the couple will be assessed using the Actor-Partner Interaction Model, a mixed-effects linear regression model able to estimate both the association of partner characteristics with partner and patient outcomes and the association of patient characteristics with both outcomes.

DISCUSSION

The web-based tool represents a novel approach to addressing the sexual health needs of prostate cancer survivors and their partners that-if found efficacious-will improve access to much needed specialty care in prostate cancer survivorship.

TRIAL REGISTRATION

Clinicaltrials.gov registration # NCT02702453 , registered on March 3, 2016.

Effects of open-label lisdexamfetamine dimesylate on self-reported quality of life in adults with ADHD

OBJECTIVE

To assess improvements in quality of life measurements during the open-label portion of a trial examining duration of efficacy of lisdexamfetamine dimesylate in a simulated adult workplace environment.

METHODS

A 4-week, open-label, dose-optimization phase followed by a randomized, double-blind, multicenter, placebo-controlled, 2-way crossover phase to evaluate safety and efficacy of lisdexamfetamine dimesylate in the adult workplace environment was conducted. Clinical assessments included the ADHD Impact Module for Adults (AIM-A) to assess the effect of lisdexamfetamine dimesylate on perception of quality of life and the Clinical Global Impressions-Severity/Improvement to assess symptom severity at baseline and improvement over time. Safety assessments included physical examination, treatment-emergent adverse events, vital signs, and electrocardiogram measurements.

RESULTS

Questions 1 and 4 of the AIM-A suggest improvement from baseline in overall quality of life at week 4 with lisdexamfetamine dimesylate treatment. Post-hoc analysis revealed no significant differences attributable to either age or sex. Overall responses to questions 2 and 3, which related to overall life goals, did not change in a majority of participants during the 4-week open-label phase of this study. For all lisdexamfetamine dimesylate doses combined, treatment-emergent adverse events occurring in ≥ 5% of participants during the dose-optimization phase were decreased appetite (36.6%), dry mouth (30.3%), headache (19.7%), insomnia (18.3%), upper respiratory tract infection (9.9%), irritability (8.5%), nausea (7.7%), anxiety (5.6%), and feeling jittery (5.6%).

CONCLUSIONS

At the end of the dose-optimization phase, lisdexamfetamine dimesylate treatment suggested quality of life improvements in adults with ADHD, with a safety profile consistent with long-acting stimulant use.

Effect size of lisdexamfetamine dimesylate in adults with attention-deficit/hyperactivity disorder

OBJECTIVE

To examine duration of efficacy of lisdexamfetamine dimesylate (LDX) in adults with attention-deficit/hyperactivity disorder (ADHD) by effect size in performance and symptom improvement in a simulated adult workplace environment (AWE).

METHODS

Adults (aged 18-55 years) with ADHD enrolled in the AWE study of LDX with open-label dose-optimization and randomized, placebo-controlled, double-blind, 2-way crossover phases. Efficacy measures included the Permanent Product Measure of Performance (PERMP)-Attempted (-A) and PERMP-Correct (-C) scores assessed throughout the day and the ADHD Rating Scale IV (ADHD-RS-IV) with adult prompts. Model-based least-squares (LS) mean effect size was assessed for PERMP and post-hoc ADHD-RS-IV with adult prompts. Remission was defined as an ADHD-RS-IV total scores ≤ 18. Safety assessments included treatment-emergent adverse events (TEAEs) and vital signs.

RESULTS

Least-squares mean (standard error [SE]) effect sizes were 0.9 (0.17) for PERMP-A and 0.8 (0.16) for PERMP-C for all postdose sessions. For PERMP-A, postdose LS mean (SE) effect sizes were 0.5 (0.15), 0.8 (0.16), 0.7 (0.16), 0.7 (0.16), 0.7 (0.16), and 0.6 (0.16) at 2, 4, 8, 10, 12, and 14 hours, respectively. Medium-to-large effect sizes (0.5-0.8) were generally maintained from 2 to 14 hours for all PERMP assessments. Overall LS mean (SE) ADHD-RS-IV total and subscale effect sizes were -1.2 (0.19), -1.2 (0.19), and -1.0 (0.17), respectively. Remission was achieved in 67.6% of participants receiving LDX. Treatment-emergent adverse events (≥ 5% with LDX) during the 4-week dose-optimization phase were decreased appetite, dry mouth, headache, insomnia, upper respiratory tract infection, irritability, nausea, anxiety, and feeling jittery. During the crossover week on LDX, there were no TEAEs ≥ 5%.

CONCLUSIONS

In adults studied in the AWE, medium-to-large model-based effect sizes were maintained from 2 to 14 hours postdose, on a performance-based measure of productivity, suggesting participants experienced improvement in sustained attention throughout the day and into the evening hours. Lisdexamfetamine dimesylate demonstrated a safety profile consistent with long-acting stimulants.

Effects of OROS methylphenidate on academic, behavioral, and cognitive tasks in children 9 to 12 years of age with attention-deficit/hyperactivity disorder

OBJECTIVE

To assess effects of OROS methylphenidate on cognitive and academic tasks in 9 to 12 year olds with attention-deficit/hyperactivity disorder (ADHD).

METHODS

A double-blind, within-subject, crossover design was used to compare OROS methylphenidate with placebo in a laboratory classroom setting on several cognitive and academic tasks for 68 children who met randomization criteria.

RESULTS

Performance on the following measures was significantly better when children received individually optimized OROS methylphenidate than placebo: math fluency and accuracy measured by the Permanent Product Math Test, ADHD symptoms observed in the laboratory setting, computerized indices of attention and impulsivity as measured by the Test of Variables of Attention (TOVA), and visual-spatial working memory (Finger Windows Backwards). Study medication was well tolerated; adverse events were generally consistent with previous reports.

CONCLUSIONS

OROS methylphenidate improves performance on measures of attention and vigilance, behavior, and working memory in a laboratory school setting in 9 to 12 year olds with ADHD.

Randomized, double-blind, placebo-controlled, crossover study of the efficacy and safety of lisdexamfetamine dimesylate in adults with attention-deficit/hyperactivity disorder: novel findings using a simulated adult workplace environment design

BACKGROUND

Duration of efficacy and safety of lisdexamfetamine dimesylate (LDX) was assessed in adults (18-55 years) with attention-deficit/hyperactivity disorder (ADHD) using the simulated adult workplace environment.

METHODS

After open-label dose optimization (4-week) with LDX, 30-70 mg/d, subjects entered a 2-week randomized, double-blind, placebo-controlled crossover phase. Efficacy assessments included the Permanent Product Measure of Performance (PERMP) total score (attempted+correct) measured predose and from 2 to 14 hours postdose, averaged across postdose sessions (primary) and at each time point vs placebo (secondary), and ADHD Rating Scale IV (ADHD-RS-IV) with adult prompts at baseline and crossover visits. Safety assessments included treatment-emergent adverse events (TEAEs), vital signs, and electrocardiograms.

RESULTS

Of 127 randomized subjects, 105 were in the intention-to-treat population and 103 completed the study. While receiving LDX vs placebo, adults had greater improvement (P < .0001) in average PERMP total scores as measured by difference in least squares (LS) mean (95% CI): 23.4 (15.6, 31.2). Absolute (P <or= .0017 for each time point) and change from predose (P < .001 for each time point) PERMP total scores were greater at all postdose time points from 2 to 14 h for adults while receiving LDX vs placebo. LDX demonstrated efficacy vs placebo (P < .0001) by the difference in LS mean (95% CI) for ADHD-RS-IV total scores: -11.5 (-14.2, -8.9). TEAEs (>or=10%) during dose optimization were decreased appetite, dry mouth, headache, and insomnia; no TEAEs >or=5% were reported during crossover phase for adults receiving LDX.

CONCLUSIONS

LDX significantly improved PERMP scores vs placebo and maintained improvement throughout the day from the first (2 hours) to last (14 hours) postdose time point vs placebo in adults with ADHD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00697515. Safety and Efficacy Workplace Environment Study of Lisdexamfetamine Dimesylate (LDX) in Adults With Attention-Deficit Hyperactivity Disorder (ADHD) http://www.clinicaltrials.gov/ct2/show/NCT00697515?term=NCT00697515&rank=1.

A randomized, double-blind, crossover study of once-daily dexmethylphenidate in children with attention-deficit hyperactivity disorder: rapid onset of effect

BACKGROUND

Long-acting methylphenidate formulations provide control of attention-deficit hyperactivity disorder (ADHD) symptoms for up to 12 hours; however, not all formulations have rapid onset of therapeutic effect, which is essential for providing symptom control during morning hours. The primary objective of this randomized, double-blind, crossover study was to assess the efficacy of dexmethylphenidate extended release (ER) versus placebo by measuring the change from pre-dose to 0.5 hours post-dose on the Swanson, Kotkin, Agler, M-Flynn and Pelham (SKAMP) rating scale.

METHODS

Eighty-six children (6-12 years) with ADHD diagnosed using the DSM-IV criteria were randomized to receive dexmethylphenidate ER 20 mg/day or placebo, sequentially, for 7 days, with the final dose administered in a laboratory classroom setting on day 7 of each treatment period. The primary efficacy comparison was change in the SKAMP-Combined score from pre-dose to 0.5 hours post-dose, with additional secondary assessments at 1, 2, 4, 6 and 8 hours post-dose. Secondary efficacy measures included change from pre-dose at all timepoints in the SKAMP-Attention and SKAMP-Deportment, Math Test-Attempted and Math Test-Correct scores, and change from baseline on the Conners' ADHD/DSM-IV Scale for Parents (CADS-P). In an exploratory analysis, a daily diary card was completed by parents on the children's in-home behaviour before school. Safety was assessed by occurrence of adverse events, monitoring of vital signs and interpretation of ECGs.

RESULTS

Significant improvements were noted at 0.5 hours and at all timepoints post-dose throughout the 8-hour laboratory classroom day for dexmethylphenidate ER vs placebo in the primary outcome measure of the SKAMP-Combined scores (p < 0.001), as well as SKAMP-Attention, SKAMP-Deportment, Math Test-Attempted and Math Test-Correct scores (p < 0.05). The changes from baseline in CADS-P scores were significantly greater with dexmethylphenidate ER than placebo (-16.382 vs -4.622; p < 0.001). Responses to all diary questions indicated significant improvement with dexmethylphenidate ER treatment versus placebo (all p < 0.001). The most common adverse events were abdominal pain (dexmethylphenidate ER 3.5%; placebo 4.7%), headache (dexmethylphenidate ER 3.5%; placebo 2.3%) and increased appetite (dexmethylphenidate ER 0%; placebo 3.5%).

CONCLUSION

Compared with placebo, once-daily dexmethylphenidate ER 20 mg provided rapid and significant improvement at 0.5 hours post-dose in attention, deportment and academic performance, which was sustained for 8 hours post-dose. Overall, once-daily dexmethylphenidate ER 20 mg was well tolerated. In an analysis of parental assessment of diary responses, children appeared more organized, and morning preparation for school was smoother and less frustrating with once-daily dexmethylphenidate ER compared with placebo.

Clear cell carcinoma of the ovary: a remarkable case

Clear cell carcinoma of the ovary is uncommon, and there are few reports of successful long-term therapy. In this case report, a previously healthy preadolescent presented with clear cell carcinoma of the ovary. After progressing through two regimens of chemotherapy, she was given topotecan, which arrested the disease. Nearly 3 years later, she continues to lead a near-normal life as a high school student. Our treatment plan is to continue to administer this therapy at monthly intervals until relapse. Although the achievement of stable disease with topotecan is frequently observed in patients relapsing with epithelial ovarian cancer, durable stable disease in clear cell carcinoma of the ovary is unusual. Treatment--and long-term maintenance therapy--with topotecan may be an option in such patients. In this case, the lack of cumulative toxicities allows the patient to maintain her usual daily activities.

Dimensional stability of impression materials immersed in an iodophor disinfectant

The potential for disease transmission has increased the importance of infection control in the dental laboratory. Impressions must be disinfected without altering their accuracy. The purpose of this study was to determine the dimensional stability of three impression materials: irreversible hydrocolloid, reversible hydrocolloid, and poly(vinyl siloxane). Thirty-six impressions were made with each material and divided into control, 10-minute, and 30-minute immersion groups using an iodophor as the disinfectant. A microscope was used to measure dimensional changes in the stone casts made from each group of impressions, and the percent change was analyzed using a two-way ANOVA. All dimensional changes after iodophor disinfection were small and within established limits.

Isolation and partial purification of growth factors with TGF-like activity from human malignant gliomas

The effect of concentrated conditioned medium from each of eight human malignant glioma cell lines on the growth of indicator cells (normal rat kidney fibroblasts (NRK), clone 14) was determined in monolayer and in soft agar assay systems. The conditioned medium from all cell lines was mitogenic in the monolayer assay, but only SF-210, U-343 MG-A, and U-251 MG produced soluble factors that caused NRK cells to grow in soft agar. The soluble growth-promoting factors from these three cell lines were acid- and heat-stable (60 degrees C for 30 minutes) but were inactivated by trypsin (100 microns/ml) and dithiothreitol (50 microM). The growth factors from SF-210 and U-343 MG-A were further purified by molecular-sieve chromatography. The partially purified growth factor from U-343 MG-A retained transforming growth factor (TGF)-like activity, had a molecular weight of 9 kD, was potentiated by TGF-beta in the soft agar assay, competed effectively with 125I-epidermal growth factor (EGF) radiolabeled for the EGF receptor on A 431 epidermoid carcinoma cells, and was completely inhibited by monoclonal antibodies to TGF-alpha. The partially purified growth factor from SF-210 had a molecular weight of 17 kD, was not inhibited by monoclonal antibodies to platelet-derived growth factor (PDGF) or TGF-alpha, and did not bind to a heparin-Sepharose column. These results imply that U-343 MG-A secretes a growth factor with TGF-alpha-like activity, and SF-210 secretes a TGF with neither TGF-alpha nor TGF-beta activity.

Effect of retinoids on the proliferation, morphology and expression of glial fibrillary acidic protein of an anaplastic astrocytoma cell line

We studied the effect of retinoids on the growth and differentiation of a cell line (U 343 MG-A) derived from a human malignant astrocytoma. Cultures treated with all-trans or 13-cis retinoic acid showed a dose-dependent inhibition of proliferation and a marked reduction in the mean cell number at the plateau phase of growth (3.5 x 10(6) vs. 1 x 10(7) cells/25 cm2) compared with untreated cultures. At confluence, cells treated with all-trans or 13-cis retinoic acid were contact-inhibited, whereas control cultures showed crowding, piling, and overgrowth. All-trans retinol or retinyl acetate did not inhibit growth. Astrocytoma cultures treated with all-trans retinoic acid (10(-6) M) for 5 days were modestly growth-inhibited but by day 16 had the same numbers of cells as controls; cultures that received all-trans retinoic acid for 9 days were markedly growth-inhibited for 7 days after the drug was removed. All-trans and 13-cis retinoic acid (10(-6) M) prevented the EDTA-induced cell detachment seen in control cultures. Strongly adherent all-trans retinoic-acid-treated astrocytoma cells grew at a slower rate than did readily detached all-trans retinoic-acid-treated or control cells. Cell spreading, an increased cytoplasmic:nuclear ratio, and greater numbers of broadly bipolar cells, some bearing thin cytoplasmic processes, were seen in cultures treated with 10(-6) M all-trans or 13-cis retinoic acid. Small tightly packed cuboidal cells and large broadly bipolar cells were seen in astrocytoma cultures from which all-trans retinoic acid was removed on days 5 and 9. Indirect immunofluorescence revealed more intense staining with antiserum to glial fibrillary acidic protein in cultures treated with 10(-6) M all-trans retinoic acid than in control cultures; electron-microscope examination of similarly treated cultures revealed more abundant 8-10 nm intermediate filaments than in control cultures. An enzyme-linked immunosorbent assay showed that all-trans or 13-cis retinoic acid caused a dose-dependent increase in the quantity of glial fibrillary acidic protein in the astrocytoma cells.

Application of in vivo and in vitro pharmacokinetics for physiologically relevant drug exposure in a human tumor clonogenic cell assay

The biological half-lives and decay rate constants under the conditions of a human brain tumor clonogenic cell assay were determined for six clinically used anticancer agents. The agents studied were: 1,3-bis(2-chloroethyl)-1-nitrosourea; 3-(2-chloroethyl-3-nitrosoureido-2-deoxy-D-glucopyranose; cis-diaminedichloroplatinum(II); 2,5-diaziridinyl-3,6-bis-(carboethoxyamino)-1,4-benzoquinone; 4-demethylepipodophylotoxin-D-thylidene glucoside; and 9-hydroxy-2-N-methylellipticine. In vitro decay of all six drugs was found to be according to first order kinetics. The half-lives of two drugs, namely, 1,3-bis(2-chloroethyl-1-nitrosourea and 3-(2-chloroethyl-3-nitrosoureido-2-deoxy-D-glucopyranose under the human tumor clonogenic cell assay (HTCA) conditions were found to be similar to their terminal in vivo half-lives in humans. For the other drugs, however, there was a very large difference between their in vitro and in vivo pharmacokinetics. In the case of 2,5-diaziridinyl-3,6-bis(carboethoxyamine)-1,4-benzoquinone, we observed about an 80-fold difference between its in vitro half-life of 40.76 h and its in vivo terminal half-life of 0.52 h. We describe the principles upon which these data can be used to design clinically more relevant in vitro drug exposure protocols in HTCAs. Since, generally, tumor cells are exposed to drugs in the HTCA either continuously or for a specified duration, e.g., 1 or 2 h, we computed the initial in vitro drug concentrations to which tumor cells should be exposed such that the resulting in vitro (c X t) after a 2-h or a continuous exposure will be within clinically achievable levels. The application of these in vivo and in vitro pharmacokinetic principles will provide for more physiological testing of patient tumor cell sensitivity to anticancer drugs in the HTCA, and is likely to result in lower rates of false positive responses in clinical trials using clonogenic cell assays.

An ultrastructural and immunocytochemical analysis of leptomeningeal and meningioma cultures

Using immunocytochemical methods, we localized several glycoproteins of the extracellular matrix to leptomeningeal cells and meningiomas in vitro. Three cell lines derived from normal human leptomeninges and seven from meningiomas were studied by indirect immunofluorescence to evaluate the cellular production of fibronectin, laminin, collagen type IV, and procollagen type III. All leptomeningeal cell lines stained intensely and uniformly for all matrix proteins; all meningioma cell cultures stained uniformly, but the intensity of staining varied considerably. After removal of the cells in culture adherent to glass with 25 mM ammonium hydroxide, indirect immunofluorescence demonstrated an exuberant residual extracellular residue enriched with fibronectin, laminin, collagen type IV, and procollagen type III. Electron microscopic examination of all leptomeningeal and meningioma cultures revealed desmosomes and dense tonofilament formation; in addition, granular, filamentous basement membrane-like material was abundant in the extracellular spaces of all cultures. Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of the cell layer of two leptomeningeal and four meningioma cultures showed production of interstitial collagen types I and III; diethylaminoethyl (DEAE)-cellulose chromatography of the medium demonstrated preferential production of procollagen type I. Our findings show conclusively that normal arachnoid cells in vitro synthesize several of the collagen subtypes and may be responsible for the "fibrous response" of the leptomeninges to trauma, infection, or infiltration by tumor. The similarities between leptomeningeal cells and meningiomas demonstrated by electron microscopy and by indirect immunofluorescence support the notion that meningiomas are derived from arachnoid cells. The localization of various mesenchymal glycoproteins within the intra- and extracellular spaces and the ubiquity of specialized intercellular junctions suggest that leptomeningeal cells in culture have the potential to behave like both stromal and epithelial cells.

Chemical structure of carbamoylating groups and their relationship to bone marrow toxicity and antiglioma activity of bifunctionally alkylating and carbamoylating nitrosoureas

Although the antitumor effects of chloroethylnitrosoureas have been shown to be due primarily to DNA-DNA cross-linking by the alkylating moieties of these agents, the basis of the often accompanying bone marrow toxicity has been more controversial. We report on the relative bone marrow toxicity of four model nitrosoureas with different alkylating and carbamoylating activities: 1,3-bis(2-chloroethyl)-1-nitrosourea; 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea; chlorozotozin, (2-[3-(2-chloroethyl)-3 -nitrosoureido]-2-deoxy-D-glucopyranose); and -3-(beta-D-glucopyranosyl)-1-nitrosourea. Inhibitions of DNA, RNA, and protein synthesis in murine bone marrow cells and of colony growth of myeloid precursor cells (granulocyte-macrophage colony-forming units) were used as in vitro end points of myelotoxicity. Further, we determined the antiglioma activity of the four nitrosoureas on two human gliomas in a clonogenic tumor cell assay and studied the effect of the non-nitrosourea carbamoylators potassium cyanate, chloroethyl isocyanate, cyclohexyl isocyanate, ethyl isocyanate, and ethyl isothiocyanate on granulocyte-macrophage colony-forming units. The results show that, at equivalent drug exposures, clonogenic glioma cell kill was significant and comparative for 1,3-bis(2-chloroethyl)-1-nitrosourea, 1-(2-chloroethyl)-3-(beta-D-glucopyranosyl)-1-nitrosourea, and chlorozotocin; 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea showed little activity. In contrast, granulocyte-macrophage colony-forming unit toxicity was low with chlorozotocin and 1-(2-chloroethyl)-3-(beta-D-glucopyranosyl)-1-nitrosourea and very high with 1,3-bis(2-chloroethyl)-1-nitrosourea and 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea. Of the isocyanates, bone marrow toxicity was highest with chloroethyl isocyanate and cyclohexyl isocyanate, intermediate with ethyl isocyanate, and lowest with KOCN and ethyl isothiocyanate. Our results indicate that (a) bifunctional alkylation is essential for antiglioma activity of nitrosoureas and (b) myelosuppression is at least partly linked with carbamoylation but that structural entities in the carbamoylating isocyanate rather than a quantitative degree of carbamoylation determine the degree of potential myelotoxicity.

Appointment reminders to reduce no-show rates. A stratified analysis of their cost-effectiveness

To determine whether reminders are cost-effective for an adult primary care internal medicine center, we randomized 590 scheduled, follow-up appointments to no reminder, computer-generated letter reminders, and telephoned reminders. The no-show rate was reduced from 24% in the control group to 14% in the reminder groups, and letter and telephoned reminders were equally effective. An economic analysis showed that about two thirds of the savings realized from reminders was generated in 23% of the patients whose prior predicted probability of a no-show appointment was above 20%. However, in our primary care center, computer-generated letter reminders were estimated to be cost-effective whenever the probability of a no-show was above 5%, and telephoned or manual letter reminders were estimated to be cost-effective whenever the probability of a no-show was above about 11%. Based on our sensitivity analysis, telephoned or manual letter reminders should be cost-effective in many other ambulatory settings as well, although in some settings, reminders may be restricted to patients at high risk for no-show behavior.