Directional Adhesion of Monodomain Liquid Crystalline Elastomers

Pressure-sensitive adhesives (PSAs) are widely employed in consumer goods, health care, and commercial industry. Anisotropic adhesion of PSAs is often desirable to enable high force capacity coupled with facile release and has typically been realized through the introduction of complex surface and/or bulk microstructures while also maintaining high surface conformability. Although effective, microstructure fabrication can add cost and complexity to adhesive fabrication. Here, we explore aligned liquid crystalline elastomers (LCEs) as directional adhesives. Aligned LCEs exhibit direction-dependent stiffness, dissipation, and nonlinear deformation under load. By varying the cross-link content, we study how the bulk mechanical properties of LCEs correlate to their peel strength and peel anisotropy. We demonstrate up to a 9-fold difference in peel force measured when the LCE is peeled parallel vs perpendicular to the alignment axis. Opportunities to spatially localize adhesion are presented in a monolithic LCE patterned with different director orientations.

Understanding and learning from rural drug service adaptations to opioid substitution therapy during the COVID-19 pandemic: the What C-OST? study

Introduction

In April 2020, in response to government COVID-19 advice, changes were made to the way English drug services operated. Methadone and buprenorphine were typically dispensed in 1- to 2-week supplies, and key working was conducted by phone/online. Previous studies have examined the impact of these changes on people from urban settings. This study adds the experiences and perspectives of people receiving care from drug services in rural areas and makes suggestions for future emergency planning.

Methods

Telephone semi-structured interviews were conducted with 15 people receiving care in Somerset, Wiltshire, and Suffolk, rural counties in England. Reflexive thematic analysis was used.

Results

Three overarching themes were found. "Challenges of rural lockdown" (theme 1) describes how rural community challenges, especially reduced or no rural public transport, were experienced. This hampered some OST collections, with consequential drug use. It also impeded connections to loved ones, worsening isolation. For participants who were struggling pre-pandemic, the intersection between this and their experience of revised drug service operations is embodied in "Amplification of Social Disconnection: Cut off and unheard" (theme 2). They felt a lack of support, particularly from remote provision key working. Participants who had supportive relationships and time in the pandemic occupied in ways they found meaningful, and others who struggled with anxiety or depression, found pandemic changes "Fits better with my life" (theme 3). They experienced more freedom for other things, gained support by other means, such as family, or felt more comfortable with remote engagement. A cross-cutting sub-theme "Understandable Interruptions" showed acceptance of pandemic disruptions.

Conclusion

National guidance and organizational policy impacted participants in different ways. Those who had supportive relationships and occupied time were better able to make positive use of newfound freedoms and engage with community-level support. In contrast, those who had less stability, including mental health struggles and social isolation, felt cut off and unheard, particularly from key workers. Reduced rural transport was a significant community-level issue, which impeded OST collection and social support. We suggest emergency response plans be created for individuals taking account of their pre-existing personal situations.

High potency cannabis use, mental health symptoms and cannabis dependence: Triangulating the evidence

BACKGROUND

Cannabis potency (concentration of Δ-9-Tetrahydrocannabinol) has been associated with risks of adverse mental health outcomes and addiction but no studies have triangulated evidence from self-report and objective measures of cannabis potency. We hypothesised that users of high potency cannabis would have higher levels of (a) anxiety, (b) depression and (c) psychosis-like symptoms (d) cannabis dependence than users of lower potency cannabis.

METHODS

A cross-sectional study of 410 participants donated a sample of cannabis for analysis of THC concentration and reported their cannabis potency preference. These two exposure measures were investigated for their association with cannabis dependence, depression, anxiety, and psychosis-like symptoms in separate linear/logistic regression models.

RESULTS

High potency cannabis preference was associated with a slight increased risk of cannabis dependence after adjusting for confounding, with the exception of cannabis use frequency (OR = 1.16, 95% CI 1.04-1.28). No association was found between THC concentration in cannabis and cannabis dependence. There was weak evidence of a small association between cannabis potency and depression and anxiety. There was no association between high potency cannabis preference or THC concentration in cannabis and psychosis-like symptoms.

CONCLUSIONS

Users of cannabis who preferred high potency types might be at increased risk of problematic cannabis use. This should be considered with caution as we were not able to triangulate these results with an objective measure of cannabis potency. More research is needed to understand the association between high potency cannabis use and depression and anxiety.

Association of cannabis potency with mental ill health and addiction: a systematic review

Cannabis potency, defined as the concentration of Δ⁹-tetrahydrocannabinol (THC), has increased internationally, which could increase the risk of adverse health outcomes for cannabis users. We present, to our knowledge, the first systematic review of the association of cannabis potency with mental health and addiction (PROSPERO, CRD42021226447). We searched Embase, PsycINFO, and MEDLINE (from database inception to Jan 14, 2021). Included studies were observational studies of human participants comparing the association of high-potency cannabis (products with a higher concentration of THC) and low-potency cannabis (products with a lower concentration of THC), as defined by the studies included, with depression, anxiety, psychosis, or cannabis use disorder (CUD). Of 4171 articles screened, 20 met the eligibility criteria: eight studies focused on psychosis, eight on anxiety, seven on depression, and six on CUD. Overall, use of higher potency cannabis, relative to lower potency cannabis, was associated with an increased risk of psychosis and CUD. Evidence varied for depression and anxiety. The association of cannabis potency with CUD and psychosis highlights its relevance in health-care settings, and for public health guidelines and policies on cannabis sales. Standardisation of exposure measures and longitudinal designs are needed to strengthen the evidence of this association.

Testing the validity of national drug surveys: comparison between a general population cohort and household surveys

BACKGROUND AND AIMS

There are concerns that national population-based estimates of illicit drug use are underestimated. We investigated this by comparing estimates of illicit substance use at age 24 from the Crime Survey for England and Wales (CSEW) with a birth cohort (Avon Longitudinal Study of Parents and Children, ALSPAC) and by comparing the Smoking and Alcohol Toolkit Studies (STS/ATS) to ALSPAC.

DESIGN

Cross-sectional household survey and cross-sectional data from one wave of a longitudinal birth cohort.

SETTING

England and Wales.

PARTICIPANTS

Young adults aged 23-25 reporting on substance use in 2017 to CSEW (n = 1165), ALSPAC (n = 3389) and STS/ATS (n = 950).

MEASUREMENTS

Lifetime and past-year illicit drug use, smoking status and hazardous drinking at age 24.

FINDINGS

The 2017 CSEW estimate of lifetime illicit drug use was 40.6%, compared with 62.8% in ALSPAC (risk difference % [RD%] = 22.2%; 95% CI = 18.9-25.5%; P ≤ 0.001). The RD in lifetime use between ALSPAC and the CSEW was 23.2% (95% CI = 20.0-26.4%) for cannabis, 16.9% (95% CI = 14.4-19.4%) for powder cocaine and 24.8% (95% CI = 22.6-27.0%) for amphetamine. Past-year drug use was 16.4% in CSEW, compared with 36.7% in ALSPAC (RD% = 20.3%; 95% CI = 17.6-23.0%; P ≤ 0.001). For past-year substance use, the RD between ALSPAC and the CSEW was 15.4% (95% CI = 12.9-17.9%) for cannabis, 14.8% (95% CI = 13.0%-16.6%) for powder cocaine and 15.9% (95% CI = 14.5-17.4%) for amphetamine. Levels of current smoking were similar between STS (27.4%) and ALSPAC (29.4%). Hazardous drinking was substantially higher in ALSPAC (60.3%) than the ATS (32.1%; RD% = 28.2%; 95% CI = 24.8-31.6%; P ≤ 0.001).

CONCLUSIONS

The Avon Longitudinal Study of Parents and Children provides one source of validation for measurements of drug use in government household surveys and indicates that illicit drug use may be underestimated in the Crime Survey for England and Wales.

Young-adult compared to adolescent onset of regular cannabis use: A 20-year prospective cohort study of later consequences

INTRODUCTION

This paper compares consequences of cannabis use initiated after high school with those of cannabis initiation in adolescence, with estimates of the proportion of adverse consequences accounted for by adult-onset and adolescent-onset cannabis users.

METHODS

A state-representative sample in Victoria, Australia (n = 1792) participated in a 10-wave longitudinal study and was followed from age 15 to 35 years. Exposure variable: Patterns of cannabis use across 20 years. Outcomes at age 35: Alcohol use, smoking, illicit drug use, relationship status, financial hardship, depression, anxiety and employment status.

RESULTS

Substantially more participants (13.6%) initiated regular use after high school (young-adult onset) than in adolescence (7.7%, adolescent onset). By the mid-30s, both young-adult and adolescent-onset regular users were more likely than minimal/non-users (63.5%) to have used other illicit drugs (odds ratio [OR] > 20.4), be a high-risk alcohol drinker (OR > 3.7), smoked daily (OR > 7.2) and less likely to be in relationships (OR < 0.4). As the prevalence of the young-adult-onset group was nearly double of the adolescent-onset group, it accounted for a higher proportion of adverse consequences than the adolescent-onset group.

DISCUSSION AND CONCLUSIONS

Cannabis users who began regular use in their teens had poorer later life outcomes than non-using peers. The larger group who began regular cannabis use after leaving high school accounted for most cannabis-related harms in adulthood. Given the legalisation of cannabis use in an increasing number of jurisdictions, we should increasingly expect harms from cannabis use to lie in those commencing use in young adulthood.

Rapid evidence review of harm reduction interventions and messaging for people who inject drugs during pandemic events: implications for the ongoing COVID-19 response

BACKGROUND

People who inject drugs are at increased health risk in a pandemic due to their greater susceptibility to severe disease and as a consequence of the restrictions put in place to halt the spread of infection. Harm reduction (HR) services, which aim to reduce the negative effects of drug use on health, are likely to be diminished in a pandemic. However, innovative HR interventions and messaging may also develop in response to such a crisis. It is vital to understand the most effective ways to deliver HR in pandemic situations so that guidance can be provided for current and future disruptions to service provision.

METHODS

A rapid evidence review was conducted with the aim of exploring what HR interventions and messaging are most effective during a pandemic-type situation. Ten health databases were systematically searched using terms relevant to the research aim. A search was also made of grey literature, including a targeted search of HR messaging from key national and service provider websites.

RESULTS

In the initial search, 121 pieces of evidence were identified which, after screening and de-duplication, resulted in 60 for inclusion. The included evidence consists mainly of non-peer reviewed, pre-publication or expert opinion pieces. The rapid findings suggest that HR services should be deemed essential during a pandemic, with staff supported to work safely and social distancing adaptations implemented. Services should be encouraged to operate more flexibly; for instance, in deciding the amounts of take-home supplies of injecting equipment and medications. The evidence on HR communication was very limited but key messages on infection control, uncertain drug supply and accessing services were identified.

CONCLUSIONS

This rapid evidence review identifies implications for national policy makers, commissioners and HR service providers. A person-centred rather than disease-centred approach to HR delivered by collaborating partners, as well as prioritizing tailored HR messaging, is recommended. Further research evaluating the delivery of HR services and messaging, particularly focusing on health inequalities, is urgently needed.

A Global Meta-analysis of the Prevalence of HIV, Hepatitis C Virus, and Hepatitis B Virus Among People Who Inject Drugs-Do Gender-Based Differences Vary by Country-Level Indicators?

BACKGROUND

Women-specific factors exist that increases vulnerability to drug-related harms from injection drug use, including blood-borne viruses (BBVs), but gender-based differences in BBV prevalence have not been systematically examined.

METHODS

We conducted meta-analyses to estimate country, regional, and global prevalence of serologically confirmed human immunodeficiency virus (HIV), hepatitis C virus (HCV; based on detection of anti-HCV antibody), and hepatitis B virus (HBV; based on detection of HBV surface antigen) in people who inject drugs (PWID), by gender. Gender-based differences in the BBV prevalence (calculated as the risk among women relative to the risk among men) were regressed on country-level prevalence and inequality measures (Gender inequality index, Human development index, Gini coefficient, and high, low or middle income of the country).

RESULTS

Gender-based differences varied by countries and regions. HIV prevalence was higher among women than men in sub-Saharan Africa (relative risk [RR], 2.8; 95% confidence interval [CI], 1.8-4.4) and South Asia (RR, 1.7; 95% CI, 1.1-2.7); anti-HCV was lower among women in the Middle East and North Africa (RR, 0.6; 95% CI, .5-.7) and East and Southeast Asia (RR, 0.8; 95% CI, .7-.9). Gender-based differences varied with country-levels of the BBV prevalence in the general population, human development, and income distribution.

CONCLUSION

HIV was more prevalent in women who inject drugs as compared to their male counterparts in some countries, but there is variation between and within regions. In countries where women are at higher risks, there is a need to develop gender-sensitive harm-reduction services for the particularly marginalized population of women who inject drugs.

Monolithic shape-programmable dielectric liquid crystal elastomer actuators

Soft robotics may enable many new technologies in which humans and robots physically interact, yet the necessary high-performance soft actuators still do not exist. The optimal soft actuators need to be fast and forceful and have programmable shape changes. Furthermore, they should be energy efficient for untethered applications and easy to fabricate. Here, we combine desirable characteristics from two distinct active material systems: fast and highly efficient actuation from dielectric elastomers and directed shape programmability from liquid crystal elastomers. Via a top-down photoalignment method, we program molecular alignment and localized giant elastic anisotropy into the liquid crystal elastomers. The linearly actuated liquid crystal elastomer monoliths achieve strain rates over 120% per second with an energy conversion efficiency of 20% while moving loads over 700 times the elastomer weight. The electric actuation mechanism offers unprecedented opportunities toward miniaturization with shape programmability, efficiency, and more degrees of freedom for applications in soft robotics and beyond.

Global, regional, and country-level coverage of interventions to prevent and manage HIV and hepatitis C among people who inject drugs: a systematic review

BACKGROUND

People who inject drugs (PWID) are a key population affected by the global HIV and hepatitis C virus (HCV) epidemics. HIV and HCV prevention interventions for PWID include needle and syringe programmes (NSP), opioid substitution therapy (OST), HIV counselling and testing, HIV antiretroviral therapy (ART), and condom distribution programmes. We aimed to produce country-level, regional, and global estimates of coverage of NSP, OST, HIV testing, ART, and condom programmes for PWID.

METHODS

We completed searches of peer-reviewed (MEDLINE, Embase, and PsycINFO), internet, and grey literature databases, and disseminated data requests via social media and targeted emails to international experts. Programme and survey data on each of the named interventions were collected. Programme data were used to derive country-level estimates of the coverage of interventions in accordance with indicators defined by WHO, UNAIDS, and the UN Office on Drugs and Crime. Regional and global estimates of NSP, OST, and HIV testing coverage were also calculated. The protocol was registered on PROSPERO, number CRD42017056558.

FINDINGS

In 2017, of 179 countries with evidence of injecting drug use, some level of NSP services were available in 93 countries, and there were 86 countries with evidence of OST implementation. Data to estimate NSP coverage were available for 57 countries, and for 60 countries to estimate OST coverage. Coverage varied widely between countries, but was most often low according to WHO indicators (<100 needle-syringes distributed per PWID per year; <20 OST recipients per PWID per year). Data on HIV testing were sparser than for NSP and OST, and very few data were available to estimate ART access among PWID living with HIV. Globally, we estimate that there are 33 (uncertainty interval [UI] 21-50) needle-syringes distributed via NSP per PWID annually, and 16 (10-24) OST recipients per 100 PWID. Less than 1% of PWID live in countries with high coverage of both NSP and OST (>200 needle-syringes distributed per PWID and >40 OST recipients per 100 PWID).

INTERPRETATION

Coverage of HIV and HCV prevention interventions for PWID remains poor and is likely to be insufficient to effectively prevent HIV and HCV transmission. Scaling up of interventions for PWID remains a crucial priority for halting the HIV and HCV epidemics.

FUNDING

Open Society Foundations, The Global Fund, WHO, UNAIDS, United Nations Office on Drugs and Crime, Australian National Drug and Alcohol Research Centre, University of New South Wales Sydney.

Soft Actuators for Small-Scale Robotics

This review comprises a detailed survey of ongoing methodologies for soft actuators, highlighting approaches suitable for nanometer- to centimeter-scale robotic applications. Soft robots present a special design challenge in that their actuation and sensing mechanisms are often highly integrated with the robot body and overall functionality. When less than a centimeter, they belong to an even more special subcategory of robots or devices, in that they often lack on-board power, sensing, computation, and control. Soft, active materials are particularly well suited for this task, with a wide range of stimulants and a number of impressive examples, demonstrating large deformations, high motion complexities, and varied multifunctionality. Recent research includes both the development of new materials and composites, as well as novel implementations leveraging the unique properties of soft materials.

Inflated Soft Actuators with Reversible Stable Deformations

Most soft robotic systems are currently dependent on bulky compressors or pumps. A soft actuation method is presented combining hyperelastic membranes and dielectric elastomer actuators to switch between stable deformations of sealed chambers. This method is capable of large repeatable deformations, and has a number of stable states proportional to the number of actuatable membranes in the chamber.

The role of single nucleotide polymorphisms of the ERCC1 and MMS19 genes in predicting platinum-sensitivity, progression-free and overall survival in advanced epithelial ovarian cancer

OBJECTIVE

This study aims to assess the role of polymorphisms in DNA repair genes, excision repair cross-complementation group 1 (ERCC1) and methyl-methanesulfonate sensitivity 19 (MMS19), in tumor response to platinum-based chemotherapy and survival in advanced epithelial ovarian cancer (EOC).

METHODS

Single nucleotide polymorphism (SNP) analysis was performed on the paraffin-embedded tumor tissue of women with advanced EOC, treated with platinum-based chemotherapy at the University of Oklahoma Health Sciences Center. Polymorphisms from two ERCC1 (codon-118 and C8092A) and three MMS19 (rs2211243, rs2236575 and rs872106) gene loci were evaluated by real time PCR Allelic Discrimination Assay.

RESULTS

Genotyping was performed in 107 patients, 45 platinum-sensitive and 62 platinum-resistant. ERCC1, codon-118 and C8092A genotyping was evaluable in 98 and 106 patients respectively and in all 107 patients for MMS19 polymorphisms. No differences were observed in genotype between platinum-sensitive and platinum-resistant patients. Polymorphisms in the ERCC1, codon-118 and MMS19 genes did not correlate with overall survival (OS), although a trend toward improved progression free survival (PFS) was observed in patients expressing the minor (GG) alleles of the rs872106 MMS19 gene. Women homozygous for the ERCC1-C8092A minor (AA) alleles had a significant increase in PFS compared to AC and CC patients and both AA and AC genotypes conferred improved survival over the major (CC) genotype.

CONCLUSIONS

Polymorphisms in ERCC1, codon-118 and MMS19 genes are not associated with clinical response to platinum or survival. The ERCC1-C8092A genotypes containing an "A" allele were associated with significant improvement in PFS and OS strengthening the value of this specific genotype in survival.

Design and manufacturing of a controllable miniature flapping wing robotic platform

In this work we present the design of a scalable, controllable, miniature flapping wing robot. The design effort comprises considerations of the number of driving actuators for controllability, body structure for both weight minimization and rigidity, and overall compactness of the robot design. This results in the development of the spherical four-bar transmission mechanism, with a single-wing prototype experimentally characterized. A dual-wing robot design manufactured via the smart composite microstructures technique is presented, featuring independent wing actuation. Finite-element analysis of the final airframe design is presented, ensuring vibration modes out of the operation range of the platform and high rigidity. A working prototype is manufactured and experiments are conducted characterizing the robot’s lift production capabilities and ensuring minimal wing coupling. A scaling law of the proposed design is presented based on momentum theory, predicting an increase of the lift/weight ratio with decreasing size. An optimization methodology for the parameters of a scaled down prototype is presented, based on a developed theoretical simulation and design tool. Finally, a 1/2 scaled down prototype using the optimized parameters is built and tested, featuring a lift/weight ratio of 3/8.

Bridging circuit for the resection of retroperitoneal sarcoma involving the aorta and the IVC- veno-venous to veno-arterial perfusion

A 50-year-old female underwent surgery for removal of a massive retroperitoneal sarcoma (RPS) involving the right hepatic lobe and the inferior vena cava (IVC), abdominal aorta, right lung, right hemi-diaphragm and pericardium. Resection of the RPS necessitated cross-clamping of the abdominal aorta, IVC and the hepatic artery. Cross-clamp time cannot be predicted prior to tumour resection and vascular re-construction. To prevent complications of prolonged cross-clamp time and distal hypo-perfusion, circulatory support was sought to facilitate the procedure. A perfusion circuit was designed to accommodate an easy and immediate redirection of blood flow from venovenous bypass (VVB) to veno-arterial bypass (VAB) without requiring a change of circuit and with minimum heparin administration. Furthermore, this circuit provides the added safety of an oxygenator and a heat-exchanger. Utilising the circuit enabled successful resection of the RPS. The patient was discharged from the intensive care unit (ICU) seven days later without any post-operative complications. This case report of a design of a perfusion circuit for the resection of RPS made use of a perfusion approach that had not previously been described and allowed for a reduction in the duration of ischaemic time and retroperitoneal bleeding.

Can low-fat/cholesterol nutrition counseling improve food intake habits and hyperlipidemia of renal transplant patients?

OBJECTIVE

To assess the impact of low-fat/cholesterol nutrition counseling on food intake habits and blood lipid levels of renal transplant patients.

DESIGN

Prospective practice-based outcome study.

SETTING

Acute care hospital post-renal transplant outpatient clinic.

PATIENTS

Forty-three renal transplant patients not on lipid-lowering medications referred to the renal dietitian for low-fat/cholesterol nutrition counseling between September 1994 and September 1997.

INTERVENTION

Individual assessment and counseling using the Healthy Heart Nutrition Guidelines Step 1 diet (<30% of total calories from fat, <300 mg cholesterol, and <10% of total calories from saturated fatty acids).

MAIN OUTCOME MEASURES

Three-day food records precounseling and 3-day food records (n = 13) or descriptive intake changes (n = 30) postcounseling (time interval: 2 to 8 months). Fasting/random serum total cholesterol, high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C), as available.

RESULTS

Total cholesterol (n = 43) and LDL-C (n = 22) decreased significantly (0. 54 mmol/L P <.000 and 0.53 mmol/L P <.000, respectively). There were no significant changes in HDL-C and triglycerides. Twenty percent of patients (n = 43) reached target levels of total cholesterol <5.2 mmol/L, and 35% of patients (n = 22) reached target levels of LDL-C <3.4 mmol/L. Percentage of total calories from fat decreased significantly (7.58% P <.03). Descriptive intake changes of lower fat choices were reported in the no post-food records group.

CONCLUSION

Patients can make changes in food intake habits after nutrition counseling. Serum lipid levels can improve after nutrition counseling, but many patients may still require lipid lowering medications to reach target levels. Nutrition counseling should be considered for the initial treatment of hyperlipidemia in renal transplant patients.

Effects of cardiopulmonary bypass on systemic vascular resistance

During cardiopulmonary bypass (CPB), complex neuroendocrine responses occur and result in haemodynamic changes. Systemic vascular resistance (SVR) before, during, and after CPB was documented in patients undergoing coronary artery bypass surgery. Whilst the overall effect was an increased SVR, transient profound decreases in SVR at the commencement of CPB, during the rewarming phase, and immediately on weaning off CPB were demonstrated.

Our professional responsibilities relative to human-animal interactions

An interesting area with great potential for benefiting and enriching the lives and conditions of people and animals is opening to us in research, service and teaching. By working with colleagues in other disciplines, we can develop new and creative ways to realize the great promise inherent in people-animal interactions properly studied and utilized.Veterinarians who understand that a strong human-companion animal bond can augment people's mental and physical states will help develop sound and effective companion animal programs for individuals who are lonely or handicapped and for persons in the school systems of the community, as well as its hospices, nursing and convalescent homes, prisons and other institutions. Children experiencing the deep satisfaction of interacting with animals while young will more likely become responsible pet owners and advocates as adults. The image of the profession is enhanced when children and adults see veterinarians as concerned teachers and compassionate health professionals.We as professionals will be required not only to update our knowledge and skills, but to acquire new knowledge in fields of animal and human behavior, psychology and sociology. We are needed on interdisciplinary research teams to study human-animal interactions. We will also be asked to commit time and personal energies in community programs, sometimes with no remuneration. But if skilled health professionals like veterinarians do not take the lead in establishing sound, long-term companion animal programs in their own communities, everyone will suffer including the animals. How we, as individual professionals, respond will be an important reflection of our compassion and our humanity.

The persistence of DNA damage in the pancreas of syrian golden hamsters treated with N-nitrosobis(2-oxopropyl)-amine

DNA damage was estimated in the liver, pancreas and salivary gland of Syrian hamsters given N-nitrosobis(2-oxopropyl)amine (BOP) by alkaline sucrose gradient centrifugation. A single BOP dose (10 mg/kg) produced in all 3 tissues extensive DNA damage that was largely repaired in the salivary gland by 4 weeks, while in the liver and pancreas, some DNA damage persisted until 4 weeks. When higher BOP doses (20 and 40 mg/kg) were used, considerable DNA damage was still evident in the pancreas, but not in the liver at 6 weeks. Greater damage persisted in hamsters given 40 mg/kg, compared with those administered 20 mg/kg.

Femoral tibial bypass grafts

The results of 53 femoral to tibial artery bypass grafts have been reviewed. All were carried out in an attempt to salvage severely ischemic extremities which resulted from arteriosclerotic occlusive disease involving the femoral, popliteal, and tibial arterial systems as demonstrated by arteriography. Most grafts were done with autogenous vein; however, composite grafts comprised of a Dacron prosthesis and an autogenous vein and homologous veins were used in several patients. The initial salvage rate in these pregangrenous extremities was 74%. Fifty-two percent of the grafts remain patent at this writing, a period of 56 months in some instances. This study indicates that most patients with a severely ischemic extremity are candidates for revascularization and should have angiographic studies before amputation is considered.