Clinical effectiveness and cost-impact after 2 years of a ketogenic diet and virtual coaching intervention for patients with diabetes

AIM

We previously evaluated the impacts at 5 months of a digitally delivered coaching intervention in which participants are instructed to adhere to a very low carbohydrate, ketogenic diet. With extended follow-up (24 months), we assessed the longer-term effects of this intervention on changes in clinical outcomes, health care utilization and costs associated with outpatient, inpatient and emergency department use in the Veterans Health Administration.

MATERIALS AND METHODS

We employed a difference-in-differences model with a waiting list control group to estimate the 24-month change in glycated haemoglobin, body mass index, blood pressure, prescription medication use, health care utilization rates and associated costs. The analysis included 550 people with type 2 diabetes who were overweight or obese and enrolled in the Veterans Health Administration for health care. Data were obtained from electronic health records from 2018 to 2021.

RESULTS

The virtual coaching and ketogenic diet intervention was associated with significant reductions in body mass index [-1.56 (SE 0.390)] and total monthly diabetes medication usage [-0.35 (SE 0.054)]. No statistically significant differences in glycated haemoglobin, blood pressure, outpatient visits, inpatient visits, or emergency department visits were observed. The intervention was associated with reductions in per-patient, per-month outpatient spending [-USD286.80 (SE 97.175)] and prescription drug costs (-USD105.40 (SE 30.332)].

CONCLUSIONS

A virtual coaching intervention with a ketogenic diet component offered modest effects on clinical and cost parameters in people with type 2 diabetes and with obesity or overweight. Health care systems should develop methods to assess participant progress and engagement over time if they adopt such interventions, to ensure continued patient engagement and goal achievement.

The changing landscape of infections in the lung transplant recipient

PURPOSE OF REVIEW

Infections in lung transplant recipients remain a major challenge and can affect lung allograft function and cause significant morbidity and mortality. New strategies for the prevention and treatment of infection in lung transplantation have emerged and are reviewed.

RECENT FINDINGS

For important vaccine preventable infections (VPIs), guidance has been updated for at risk solid organ transplant (SOT) recipients. However, data on the efficacy of newer vaccines in lung transplant, including the respiratory syncytial virus (RSV) vaccine, are limited. Studies demonstrate improved vaccination rate with Infectious Diseases consultation during pretransplant evaluation. Two new antiviral agents for the treatment and prevention of cytomegalovirus (CMV) in SOT, letermovir and maribavir, are bein incorporated into clinical care. CMV-specific cell-mediated immune function assays are more widely available. Antibiotics for the management of multidrug resistant pathogens and Burkholderia cepacia complex have been described in case series and case reports in lung transplant.

SUMMARY

Although new vaccines and novel therapies for preventing and treating infections are available, larger studies evaluating efficacy in lung transplant recipients are needed.

Telehealth Access and Substitution in the VHA

BACKGROUND

In response to COVID-19, the Veterans Health Administration (VHA) expanded telehealth availability, allowing veterans to receive care at home. We explore the extent of substitution of telehealth for in-person care among medical centers (facilities), providers, and patients. We explore the extent to which patient preferences drive telehealth utilization, and compare access to care (as measured by waiting times) for telehealth and in-person visits.

METHODS

We use VHA electronic health records to identify scheduled outpatient mental health (MH) appointments from January 2019 through February 2023 focusing on care delivered by social workers, psychologists, and psychiatrists. For each quarter, we compute the proportion of completed appointments that were delivered via phone or video by each facility, provider, and patient and show the changes in these proportions before, during, and after the onset of COVID-19. To explore patient preferences, we match providers of patients with high rates of telehealth utilization and examine the extent to which those providers deliver in-person care. To examine access to care, we compute waiting times for in-person, video, and phone new patient appointments. We investigate differences between urban and rural patients, and patients of different ages.

KEY RESULTS

Telehealth for MH grew dramatically in the VHA after the onset of COVID-19. While some facilities provided more telehealth than others, all facilities (as of early 2023) provided some telehealth MH services. Approximately 86% of individual providers provided telehealth, with 27% scheduling MH appointments almost exclusively as telehealth appointments and 59% providing a mix. Patients exhibited more polarization, with 36% scheduling only in-person visits for almost all their MH visits and 56% of them scheduling exclusively telehealth, and only 8% of them utilizing a mix of modalities. Of those who exclusively received telehealth care, a majority of them utilized video (80%) over phone (20%). Take-up of MH among younger patients was higher relative to older patients. Urban patients used telehealth more than rural patients. Patient preferences rather than provider preferences drove utilization of patients who almost exclusively utilized telehealth. Between April 2021 and February 2023, the average difference in waiting time for in-person and video appointments was less than 1 day, with comparable appointment volumes, suggesting that the supply of and demand for in-person and video were not different enough to merit waiting longer. Telehealth was chosen over in-person more among urban and younger patients, as older and rural patients exhibited higher willingness to wait for in-person over video appointments. By contrast, appointment volumes and waiting times for phone appointments were lower across all groups, suggesting that phone may not be as substitutable for in-person visits in MH.

CONCLUSIONS

We find that the VHA has made telehealth widely available, providing access to many veterans. While telehealth utilization has increased, face-to-face care persists for MH services, suggesting that one modality may not serve all purposes and preferences for care. Patient preferences drive the modality decision among those who exclusively use MH care via telehealth. For those who persist in mostly utilizing in-person care, there may be various factors influencing those preferences such as issues with limited internet connectivity, language barriers, and digital literacy, especially for older and rural patients who utilize in-person care more than those who are younger and more urban. Further investigation is required to investigate the optimal mix of modalities which may allow for potential increases in patient satisfaction, quality of care, and clinic efficiency.

Effect of Mycetoma in Lung Transplant Patients - a Single Center Experience

BACKGROUND

Mycetomas are uncommon in lung transplant recipients. Prior studies have shown increased mortality associated with mycetoma in lung transplant recipients (LTR). We reviewed our center's experience in outcome of LTRs with pre -or post-transplant mycetoma.

METHODS

We retrospectively reviewed electronic health records of LTRs performed at our institute between January 1, 2013 to December 31, 2020.

RESULTS

Mycetoma was present in less than 1 percent of LTR patients (7/1086). Mean age at the time of the transplant was 65 years. Idiopathic pulmonary fibrosis (5/7), interstitial lung disease (1/7), and sarcoidosis (1/7) were underlying pulmonary diagnoses. Seventy-one percent (5/7) received single lung transplant and 29% received double lung transplant. Seventy-one percent had negative serum galactomannan vs 29% (2/7) of patients who had positive serum galactomannan (one post and one pre). Fifty-seven percent had positive bronchoalveolar aspergillus galactomannan (23% had negative). A total of 42% (3/7) were found to have mycetoma before transplant and 58% (4/7) had mycetoma post transplant. Chest computed tomography findings in all patients were consistent with mycetoma.

CONCLUSIONS

In our cohort of patients, mycetoma was not found to be the primary cause of death if diagnosed pre transplant. Transplant recipients with mycetoma pre transplant did not develop invasive fungal infection or mycetoma post transplant. Careful evaluation of lung transplant candidates with mycetoma is critical. Further studies are needed to determine optimal duration of antifungal therapy and to determine if surgical resection may be needed to manage post-lung transplant mycetoma.

First Case of Cupravidus paculus Infection in a Lung Transplant Recipient: A Case Report

Cupravidus paculus is a rare Gram-negative bacterium that can cause a wide range of severe infections, largely in immunocompromised patients. It is a ubiquitous organism found in natural and man-made environments and in the hospital. Herein, we present the first case of C. paculus infection in a lung transplant recipient, which required prolonged antibiotic therapy to achieve complete clearance. Additionally, we review the existing literature on the clinical and microbiological profile of C. paculus, along with previously documented cases of clinical infections. Our case highlights the potential sources of C. paculus infections, the importance of appropriate disinfection protocols for medical devices, and the need for antibiotic sensitivities to guide treatment.

Effectiveness of a ketogenic diet and virtual coaching intervention for patients with diabetes: A difference-in-differences analysis

AIM

To test the effectiveness of a ketogenic diet and virtual coaching intervention in controlling markers of diabetes care and healthcare utilization.

MATERIALS AND METHODS

Using a difference-in-differences analysis with a waiting list control group-a quasi-experimental methodology-we estimated the 5-month change in HbA1c, body mass index, blood pressure, prescription medication use and costs, as well as healthcare utilization. The analysis included 590 patients with diabetes who were also overweight or obese, and who regularly utilize the Veterans Health Administration (VA) for healthcare. We used data from VA electronic health records from 2018 to 2020.

RESULTS

The ketogenic diet and virtual coaching intervention was associated with significant reductions in HbA1c (-0.69 [95% CI -1.02, -0.36]), diabetes medication fills (-0.38, [-0.49, -0.26]), body mass index (-1.07, [-1.95, -0.19]), diastolic blood pressure levels (-1.43, [-2.72, -0.14]), outpatient visits (-0.36, [-0.70, -0.02]) and prescription drug costs (-34.54 [-48.56, -20.53]). We found no significant change in emergency department visits (-0.02 [-0.05, 0.01]) or inpatient admissions (-0.01 [-0.02, 0.01]).

CONCLUSIONS

This real-world assessment of a virtual coaching and diet programme shows that such an intervention offers short-term benefits on markers of diabetes care and healthcare utilization in patients with diabetes.

Early post-transplant cutaneous bacillary angiomatosis in a kidney recipient: Case report and review of the literature

Bacillary angiomatosis (BA) is an uncommon systemic disease caused by Bartonella henselae (BH) or Bartonella quintana (BQ) that occurs primarily in immunocompromised hosts. Few cases of BA recipients have been reported in adult solid transplant recipients over the years, with most cases presenting years after transplant. We describe a case of a kidney transplant recipient who developed cutaneous BA very early in the post-transplant period despite not having any exposures. Retrospective testing of donor and recipient's serum was performed and raised the concern for possible donor-derived infection. A literature review encompassing 1990 to present was also performed in order to better understand the clinical presentation, diagnostics and therapeutic approach of this unusual disease. Combined serology, histopathology and molecular testing (polymerase chain reaction [PCR]) were useful in diagnosing BA in our patient as serology alone might be unreliable. Macrolides or doxycycline for at least 3 months is the recommended therapeutic strategy; however, the optimal duration of treatment is not well established in transplant recipients. In our patient, we decided to use doxycycline for 1 year due to gradual resolution of lesions and ongoing immunosuppression. Patient responded successfully without any documented relapse.

582. Safety and Efficacy of High-Dose Ganciclovir versus Standard Dosing for Cytomegalovirus Viremia in Solid Organ Transplant (SOT) Recipients

Background

Standard dose ganciclovir (SD-GCV) for treatment of CMV infection/disease is 5 mg/kg every 12 hours, although higher doses (7.5–10 mg/kg every 12 hours) may be considered for resistant CMV. Literature on safety/efficacy of high dose GCV (HD-GCV) is limited. We sought to evaluate safety and clinical outcomes of SD-GCV vs HD-GCV strategies.

Methods

Retrospective single center study of adult SOT recipients with CMV viremia from 1/1/2017-1/31/2019 who received IV GCV therapy. Primary objective was to compare incidence of cytopenias between SD-GCV and HD-GCV. Secondary outcomes compared CMV viremia clearance, incidence of CMV disease and recurrent viremia within 30 days, granulocyte colony stimulating factor (G-CSF) use, and antiviral resistance testing rates.

Results

We evaluated 121 patients: 74 received SD-GCV, 47 received HD-GCV. Baseline characteristics were similar between groups. Most patients received a liver transplant (46% SD vs 36% HD) and had D+/R- CMV serostatus (55.4% SD vs 68% HD). Induction immunosuppression occurred in 75%, mostly with anti-thymocyte globulin. Median baseline CMV viral loads were similar (4620 IU/mL SD vs 7770 IU/mL HD, p=0.25).

Incidence of cytopenias was similar between groups: leukopenia (43% SD vs 43% HD, p=0.96), neutropenia (15% SD vs 13% HD, p= 0.75), thrombocytopenia (24% SD vs 31% HD, p=0.62). HD-GCV did not significantly impact CMV clearance (HR: 0.79 [95% CI 0.52–1.21], p=0.27). There was no difference in incidence of CMV disease (35% SD vs 38% HD, p=0.72) or incidence of recurrent CMV viremia (15% SD vs 28% HD, p=0.098).

G-CSF requirement was not different (23.7% SD vs 14.3% HD, p=0.295), however, patients on HD-GCV received more doses of G-CSF (median 2 SD vs 5 HD, p=0.001). More patients in HD-GCV group were tested for antiviral resistance: 15 (21%) SD vs 20 (43%) HD, p=0.01. Of these, there was no difference in rate of resistance detection (7/15 (47%) SD vs 11/20 (55%) HD, p=0.95).

Conclusion

Therapy with HD-GCV did not demonstrate increased incidence of cytopenias compared to SD-GCV, nor did we observe improved time to CMV clearance or incidence of CMV disease between groups. Opportunities exist for improving stewardship of antiviral resistance testing and use of G-CSF when considering HD-GCV therapy.

Disclosures

All Authors: No reported disclosures

Vector-based kernel weighting: A simple estimator for improving precision and bias of average treatment effects in multiple treatment settings

Treatment effect estimation must account for observed confounding, in which factors affect treatment assignment and outcomes simultaneously. Ignoring observed confounding risks concluding that a helpful treatment is not beneficial or that a treatment is safe when actually harmful. Propensity score matching or weighting adjusts for observed confounding, but the best way to use propensity scores for multiple treatments is unknown. It is unclear when choice of a different weighting or matching strategy leads to divergent inferences. We used Monte Carlo simulations (1000 replications) to examine sensitivity of multivalued treatment inferences to propensity score weighting or matching strategies. We consider five variants of propensity score adjustment: inverse probability of treatment weights, generalized propensity score matching, kernel weights (KW), vector matching, and a new hybrid that is easily implemented-vector-based kernel weighting (VBKW). VBKW matches observations with similar propensity score vectors, assigning greater KW to observations with similar probabilities within a given bandwidth. We varied degree of propensity score model misspecification, sample size, treatment effect heterogeneity, initial covariate imbalance, and sample distribution across treatment groups. We evaluated sensitivity of results to propensity score estimation technique (multinomial logit or multinomial probit). Across simulations, VBKW performed equally or better than the other methods in terms of bias, efficiency, and covariate balance measured via prognostic scores. Our simulations suggest that VBKW is amenable to full automation and is less sensitive to PS model misspecification than other methods used to account for observed confounding in multivalued treatment analyses.

Alternative pneumocystis prophylaxis in solid organ transplant recipients at two large transplant centers

BACKGROUND

Trimethoprim-sulfamethoxazole (TMP-SMX) is the drug of choice for Pneumocystis jirovecii pneumonia (PJP) prophylaxis and has activity against other opportunistic infections (OIs) after solid organ transplant (SOT). We aimed to describe the incidence, reasons for and outcomes of use of alternative prophylactic agents (APAs) across SOT programs in our high volume centers.

METHODS

Solid organ transplant recipients (SOTRs) at our centers from 1/2015-12/2016 were identified. Pharmacy records identified APA (pentamidine, atovaquone, or dapsone) use within 1 year. Records were reviewed for allergies, laboratory values at APA initiation, diagnostic tests for TMP-SMX-preventable OIs, and APA side effects.

RESULTS

An APA was initiated in 105/1173 (8.9%) SOTRs. Of these, 51 (48.6%) were because of sulfonamide allergy recorded pre-SOT, mostly rash/hives (58.8%). The remaining 54 (51.4%) had TMP-SMX discontinued post-SOT, mostly for neutropenia (48%) and renal effects (34%). Differences occurred across programs, with kidney transplant never stopping TMP-SMX for renal issues. Of those changed to APAs post-transplant, 19 (35%) were later successfully re-challenged with TMP-SMX. With thresholds in mind, 67 (64%) received an APA unnecessarily, accounting for up to $100 000/y excess cost. Potential TMP-SMX-preventable OIs occurred in 7 (5 Nocardia; 2 PJP). APA side effects occurred in 14/105 (13.3%).

CONCLUSIONS

Use of APAs for PJP prophylaxis after SOT is less than previously reported but often unwarranted. Such decisions require scrutiny to avoid TMP-SMX-preventable OIs, cost and important APA side effects. Use of reasonable thresholds for cessation of TMP-SMX and data-driven approaches to re-challenge would substantially reduce APA use.

398. Review of Mucormycosis Cases at the University of Colorado Hospital From 2012 to 2018 and Evaluation of Risk Factors and Appropriateness of Antifungal Prophylaxis

Background

Healthcare associated outbreaks of mucormycosis have been described in the literature. In 2017, the University of Colorado Hospital (UCH) had an increased number of cases of mucormycosis. The objective of this study was to evaluate possible risk factors and weather patterns associated with cases of mucormycosis diagnosed at UCH from 2012 to 2018 in order determine whether the current antifungal prophylaxis used at UCH should be modified.

Methods

A retrospective cohort was conducted involving patients >18 years old who were admitted to UCH between 2012 and 2018 and were diagnosed with proven or probable mucormycosis as defined by the European Organization for Research and Treatment of Cancer/Mycosis Study Group (EORTC/MSG) criteria. Medical records were reviewed, and data were collected on risk factors, antifungal prophylaxis, and mortality outcome. Weather data were collected from the National Centers for Environmental Information (NCEI).

Results

Twenty-five cases of proven or probable mucormycosis were identified. On average patients had at least two risk factors associated with mucormycosis. The most common risk factors included diabetes mellitus (DM) (13 patients), hematologic malignancy or hematopoietic stem cell transplant (HSCT) (11 patients), use of immunosuppressing medications (11 patients), and invasive procedures. (9 patients). At the time of diagnosis, only six patients were on an antifungal with mold activity. Eight patients died during hospitalization. The distribution of cases over time was compared with weather data for Colorado. A cluster of cases occurred in 2013 (6 cases) and in 2017 (8 cases). A majority of cases were diagnosed during the summer and fall months with July being the month with the most number of cases. There were higher levels of precipitation that occurred prior to or during the cluster of cases.

Conclusion

Cases of mucormycosis at UCH were associated with DM, hematologic malignancy/HSCT, use of immunosuppressive therapy, and invasive procedures. The increase of cases seen 2013 and 2017 occurred in the summer and fall months after higher levels of precipitation were observed in Colorado. Providers at UCH may consider modifying antifungal prophylaxis to include mold coverage in patients with >2 risk factors for mucormycosis who are admitted during the summer and fall.

Disclosures

M. Barron, Astellas Pharma: Investigator, Research support.

Changes in verbal and visuospatial working memory from Grade 1 to Grade 3 of primary school: Population longitudinal study

BACKGROUND

Adaptive working memory training is being implemented without an adequate understanding of developmental trajectories of working memory. We aimed to quantify from Grade 1 to Grade 3 of primary school (1) changes in verbal and visuospatial working memory and (2) whether low verbal and visuospatial working memory in Grade 1 predicts low working memory in Grade 3.

METHOD

The study design includes a population-based longitudinal study of 1,802 children (66% uptake from all 2,747 Grade 1 students) at 44 randomly selected primary schools in Melbourne, Australia. Backwards Digit Recall (verbal working memory) and Mister X (visuospatial working memory) screening measures from the Automated Working Memory Assessment (M = 100; SD = 15) were used to assess Grades 1 and 3 (ages 6-7 and 8-9 years) students. Low working memory was defined as ≥1 standard deviation below the standard score mean. Descriptive statistics addressed Aim 1, and predictive parameters addressed Aim 2.

RESULTS

One thousand seventy (59%) of 1802 Grade 1 participants were reassessed in Grade 3. As expected for typically developing children, group mean standard scores were similar in Grades 1 and 3 for verbal, visuospatial, and overall working memory, but group mean raw scores increased markedly. Compared to "not low" children, those classified as having low working memory in Grade 1 showed much larger increases in both standard and raw scores across verbal, visuospatial, and overall working memory. Sensitivity was very low for Grade 1 low working memory predicting Grade 3 low classifications.

CONCLUSION

Although mean changes in working memory standard scores between Grades 1 and 3 were minimal, we found that individual development varied widely, with marked natural resolution by Grade 3 in children who initially had low working memory. This may render brain-training interventions ineffective in the early school year ages, particularly if (as population-based programmes usually mandate) selection occurs within a screening paradigm.

Profiles of language development in pre-school children: a longitudinal latent class analysis of data from the Early Language in Victoria Study

BACKGROUND

Pre-school language impairment is common and greatly reduces educational performance. Population attempts to identify children who would benefit from appropriately timed intervention might be improved by greater knowledge about the typical profiles of language development. Specifically, this could be used to help with the early identification of children who will be impaired on school entry.

METHODS

  This study applied longitudinal latent class analysis to assessments at 8, 12, 24, 36 and 48 months on 1113 children from a population-based study, in order to identify classes exhibiting distinct communicative developmental profiles.

RESULTS

Five substantive classes were identified: Typical, i.e. development in the typical range at each age; Precocious (late), i.e. typical development in infancy followed by high probabilities of precocity from 24 months onwards; Impaired (early), i.e. high probabilities of impairment up to 12 months followed by typical language development thereafter; Impaired (late), i.e. typical development in infancy but impairment from 24 months onwards; Precocious (early), i.e. high probabilities of precocity in early life followed by typical language by 48 months. The entropy statistic (0.84) suggested classes were fairly well defined, although there was a non-trivial degree of uncertainty in classification of children. That half of the Impaired (late) class was expected to have typical language at 4 years and 6% of the numerically large Typical class was expected to be impaired at 4 years illustrates this. Characteristics indicative of social advantage were more commonly found in the classes with improving profiles.

CONCLUSIONS

Developmental profiles show that some pre-schoolers' language is characterized by periods of accelerated development, slow development and catch-up growth. Given the uncertainty in classifying children into these profiles, use of this knowledge for identifying children who will be impaired on school entry is not straightforward. The findings do, however, indicate greater need for language enrichment programmes among disadvantaged children.

Internal representation of movement in children with developmental coordination disorder: a mental rotation task

Recent studies show that children with developmental coordination disorder (DCD) have difficulties in generating an accurate visuospatial representation of an intended action, which are shown by deficits in motor imagery. This study sought to test this hypothesis further using a mental rotation paradigm. It was predicted that children with DCD would not conform to the typical pattern of responding when required to imagine movement of their limbs. Participants included 16 children with DCD and 18 control children; mean age for the DCD group was 10 years 4 months, and for controls 10 years. The task required children to judge the handedness of single-hand images that were presented at angles between 0 degrees and 180 degrees at 45 degrees intervals in either direction. Results were broadly consistent with the hypothesis above. Responses of the control children conformed to the typical pattern of mental rotation: a moderate trade-off between response time and angle of rotation. The response pattern for the DCD group was less typical, with a small trade-off function. Response accuracy did not differ between groups. It was suggested that children with DCD, unlike controls, do not automatically enlist motor imagery when performing mental rotation, but rely on an alternative object-based strategy that preserves speed and accuracy. This occurs because these children manifest a reduced ability to make imagined transformations from an egocentric or first-person perspective.

Effect of Tamoxifen on Transforming Growth Factor β1Production by Keloid and Fetal Fibroblasts

BACKGROUND

Evidence suggests that keloid scar formation may be mediated, in part, by deranged growth factor activity, including that of transforming growth factor (TGF) beta1. Tamoxifen citrate has shown promise in the treatment of keloids.

OBJECTIVE

To evaluate the effect of tamoxifen on autocrine growth factor expression in keloid and fetal dermal fibroblasts, which exhibit scar-free healing.

DESIGN

Serum-free cell lines of keloid and fetal dermal fibroblasts were established. Cell cultures were exposed to different concentrations of tamoxifen solution (8 and 12 or 16 micromol/L). Cell counts were performed and supernatants collected at 24, 48, and 96 hours. Cell-free supernatants were quantitatively assayed for TGF-beta1 expression.

RESULTS

Keloid fibroblasts show increased per-cell TGF-beta1 production compared with fetal fibroblasts. Tamoxifen appeared to decrease per-cell TGF-beta1 production at each of the time points evaluated.

CONCLUSIONS

Keloids likely arise due to locally insufficient or excessive concentrations of specific growth factors. The higher level of TGF-beta1 produced by keloid cells compared with fetal fibroblasts could be related to the aberrant wound healing seen with keloids. The addition of tamoxifen may lead to improved wound healing in keloids by decreasing the expression of TGF-beta1.

Brain-derived neurotrophic factor-enriched collagen tubule as a substitute for autologous nerve grafts

BACKGROUND

Autologous nerve interposition grafts are frequently harvested by head and neck surgeons. The sacrifice of these donor nerves guarantees some degree of morbidity, including sensory loss, additional incision sites with associated potential complications, and prolonged operative time. An alternative to autologous nerve grafting is, therefore, desirable.

OBJECTIVE

To determine if a collagen tubule (CT) filled with either a plain collagen gel or a brain-derived neurotrophic factor (BDNF)-enriched collagen gel could be used to achieve functional and histologic outcomes equivalent to an autologous nerve graft in bridging a 15-mm nerve gap in the rabbit facial nerve.

DESIGN

A prospective, randomized, blinded animal study with a control group.

METHODS

Thirty rabbit facial nerves were resected (15-mm segments) to create nerve gaps. The gaps were bridged using 1 of 3 methods, assigned randomly: a reversed facial nerve (control), a collagen gel-filled CT, or a BDNF-enriched collagen gel-filled CT. The animals were evaluated after 6 weeks in a blinded fashion for functional nerve recovery, axon count, and axonal diameter.

RESULTS

There were no significant differences between the autologous nerve graft group, the collagen gel-filled CT group, or the BDNF-enriched collagen gel-filled CT group (n = 10 for each group) for functional nerve recovery (P =.94). The mean axon count and the mean axonal diameter were highest in the BDNF-enriched collagen gel-filled CT group, but these differences failed to reach statistical significance (P =.18 and.96, respectively).

CONCLUSIONS

Collagen tubules filled with BDNF-enriched collagen gel appear to be at least as good as autologous nerve grafts for bridging short facial nerve gaps. Larger experimental studies are warranted to determine if clinical trials are justified.

Delayed repair of transected nerves: effect of brain-derived neurotrophic factor

OBJECTIVE

To determine if administration of brain-derived neurotrophic factor (BDNF) after peripheral nerve transection can improve the functional outcome in situations where epineurial repair must be delayed.

DESIGN

Randomized, blinded, controlled trial.

SUBJECTS

Thirty-four Sprague-Dawley rats.

INTERVENTION

Sciatic nerves were transected and, after a 2-week delay, repaired with epineurial sutures. Animals were assigned to receive daily administration of lactated Ringer solution (LR [control] group); BDNF delivered at the time of nerve transection through 2 weeks after nerve repair, for a total of 4 weeks (BDNF-early group); or BDNF delivered at the time of nerve repair through 2 weeks after repair (BDNF-late group). Outcome was assessed using sciatic functional indices (SFIs) and histomorphometric analysis.

RESULTS

The SFI maximal recovery was superior in the BDNF groups, but this difference did not reach statistical significance (SFI, -90.1+/-9.6 [LR group], -85.7+/-7.6 [BDNF-early group], and -84.6+/-4.8 [BDNF-late group], where normal function is 0 and complete loss of function is -100; P = .27). The mean axon diameter tended to be greater in the BDNF groups compared with the LR group, i.e., 2.43+/-0.23 microm (LR group), 2.80+/-0.44 microm (BDNF-early group), and 2.83+/-0.38 microm (BDNF-late group) (P = .05).

CONCLUSIONS

The local administration of BDNF to nerves that underwent transection and then repair after a delay resulted in an increase in axonal diameters and maximal SFIs, a difference that did not reach statistical significance. The timing of BDNF administration after nerve transection did not affect neuronal regeneration.

Growth of keloid-producing fibroblasts in commercially available serum-free media

The purpose of this study was to update our in vitro serum-free keloid fibroblast (KF) model by use of commercially available media. Prior evaluations of fibroblast characteristics in vitro, especially that of growth factor measurement, have been confounded by the presence of serum-containing media. KFs were obtained from patients undergoing facial keloid removal. The 4 commercially available serum-free media evaluated were AIM-V (Gibco, Grand Island, NY), Fibroblast Growth Medium (FGM; Clonetics, San Diego, CA), HB GRO (Irvine Scientific, Santa Ana, CA), and UltraCULTURE (BioWhittaker Inc, Walkersville, MD). The main outcome measures were sustained KF growth and viability as compared with serum-based models. The KFs in UltraCULTURE had a higher viability but did not grow as well as in FGM. The KFs in HB GRO and AIM-V demonstrated significantly decreased viability. Because of FGM's satisfactory proliferative support and viability comparable with serum-based medium, it is recommended for the in vitro propagation of keloid-producing fibroblasts.

Iron, iron-binding proteins and immune system cells

In summary, the work reviewed in the present paper indicates that 1. Iron and the iron-binding proteins can act as regulators of immune function, and not only as a result of a nutritional dependence of lymphoid cells on transferrin and transferrin-iron. Subsets of cells of the immune system respond differently to increases in iron concentration in vitro and in vivo. 2. Macrophages and lymphocytes differ in the H and L subunit content of the ferritins synthesized in response to increases in iron concentration in vitro. 3. NK activity by adherent and nonadherent cells differ in their susceptibility to the enhancing effect of lactoferrin in vitro. 4. Responses to mitogen stimulation by PHA and Con A are diminished, while the PWM response remains unaffected by exposure to acidic ferritins or by increasing concentrations of iron in vitro and in vivo. 5. Pretreatment of effector but not target cells with iron results in diminished responses in the MLR, an effect that appears to be related to the HLA-A locus. 6. In situ hybridization studies indicate that transferrin is synthesized by a specific subset of the T lymphocytes. 7. Transient increases in serum iron concentration above the full saturation of transferrin, reproducing the clinical situation frequently seen in hereditary hemochromatosis, are followed by a series of cellular changes in the synovium that can be correlated to changes in the course of an experimental model of arthritis in the rat.

Ibuprofen and diflunisal in rheumatoid arthritis: a double-blind comparative trial

Both diflunisal (750 mg/day) and ibuprofen (1600 mg/day) were shown to be superior to placebo in the treatment of rheumatoid arthritis in a double-blind cross-over trial. Neither drug affected lymphocyte transformation to plant mitogens. Diflunisal scored better than ibuprofen at the dose levels chosen but the differences did not reach significance.

A single-blind crossover trial of the anti-inflammatory drug sodium meclofenamate and placebo, including an evaluation of hand grip and of lymphocyte responsiveness

A single-blind crossover trial was carried out in 21 patients with active rheumatoid arthritis to assess the effectiveness and tolerance of sodium meclofenamate (300 mg per day) compared with placebo. After a 1-week washout period patients had two periods of active medication, each of 2 weeks, separated by 1 week on placebo. Morning stiffness, walking speed, pain score, patient impression of response, joint tenderness and power, work and maximum grip strength achieved by hand grip were all improved by sodium meclofenamate and an anti-inflammatory effect of the drug was demonstrated, with some reduction in the swelling of PIP joints. There was no advantage in assessing pain on full movement of the small joints of the hands in addition to direct tenderness. Power, work and rate of grip release achieved during hand grip provided more information about hand function than maximum grip strength alone. Lymphocyte transformation to non-specific mitogens was enhanced by the drug. Twelve patients had some form of gastro intestinal complaint during the study and it is suggested that diarrhoea is likely to prove to be the major limiting factor of acceptance by some patients.

Mechanisms of shock blood induced tissue anoxia

An isolated limb perfusion system in pigs was used to assess and relate hemodynamic variables to oxygen consumption in shock. Perfusion with shock blood results in a significantly increased peripheral vascular resistance, which can be blocked by phentolamine. However, a significantly reduced oxygen consumption seen during perfuslion with shock blood is not eliminated with phentolamine despite normal peripheral vascular resistance. The cause of the reduced oxygen consumption is not known, but the results suggest that other factors apart from a decreased blood flow due to catecholamine release are important in contributing to end organ anoxia and failure in shock.