Systematic Implementation of Effective Quality Assurance Processes for the Assessment of Radiation Target Volumes in Head and Neck Cancer

PURPOSE

Significant heterogeneity exists in clinical quality assurance (QA) practices within radiation oncology departments, with most chart rounds lacking prospective peer-reviewed contour evaluation. This has the potential to significantly affect patient outcomes, particularly for head and neck cancers (HNC) given the large variance in target volume delineation. With this understanding, we incorporated a prospective systematic peer contour-review process into our workflow for all patients with HNC. This study aims to assess the effectiveness of implementing prospective peer review into practice for our National Cancer Institute Designated Cancer Center and to report factors associated with contour modifications.

METHODS AND MATERIALS

Starting in November 2020, our department adopted a systematic QA process with real-time metrics, in which contours for all patients with HNC treated with radiation therapy were prospectively peer reviewed and graded. Contours were graded with green (unnecessary), yellow (minor), or red (major) colors based on the degree of peer-recommended modifications. Contours from November 2020 through September 2021 were included for analysis.

RESULTS

Three hundred sixty contours were included. Contour grades were made up of 89.7% green, 8.9% yellow, and 1.4% red grades. Physicians with >12 months of clinical experience were less likely to have contour changes requested than those with <12 months (8.3% vs 40.9%; P < .001). Contour grades were significantly associated with physician case load, with physicians presenting more than the median number of 50 cases having significantly less modifications requested than those presenting <50 (6.7% vs 13.3%; P = .013). Physicians working with a resident or fellow were less likely to have contour changes requested than those without a trainee (5.2% vs 12.6%; P = .039). Frequency of major modification requests significantly decreased over time after adoption of prospective peer contour review, with no red grades occurring >6 months after adoption.

CONCLUSIONS

This study highlights the importance of prospective peer contour-review implementation into systematic clinical QA processes for HNC. Physician experience proved to be the highest predictor of approved contours. A growth curve was demonstrated, with major modifications declining after prospective contour review implementation. Even within a high-volume academic practice with subspecialist attendings, >10% of patients had contour changes made as a direct result of prospective peer review.

Efficacy of incisional negative pressure therapy in preventing post-sternotomy wound complications

BACKGROUND

Sternal wound infections represent a source of significant morbidity and mortality following median sternotomy. The use of incisional negative pressure wound therapy in prevention has yet to be elucidated.

METHODS

A retrospective study was conducted before and after a universal wound care protocol was implemented including the prophylactic use of negative pressure wound therapy (NPWT). The primary endpoint was sternal infections within 90 days of the index operation.

RESULTS

In the control period, there was a 3.0% rate of sternal infection within 90 days compared to 0.8% in the intervention period (p < 0.001). An odds ratio of 0.25 (95% confidence interval 0.11, 0.57; p < 0.001) in the intervention period as compared to the control period was demonstrated.

CONCLUSIONS

The use of a standardized wound care protocol including the universal application of NPWT for patients undergoing cardiac surgery with median sternotomy was an independent predictor of decreased rates of sternal infection.

Volumetric Modulated Arc Therapy Craniospinal Irradiation Utilizing a Vertebral Body Sparing Approach: A Toxicity Analysis

PURPOSE/OBJECTIVE(S)

Craniospinal irradiation (CSI) is indicated for adult patients diagnosed with leptomeningeal disease (LMD). Proton-based vertebral-body-sparing (VBS) CSI has been explored with pediatric patients to minimize hematologic toxicity; however, utilization of VBS in an adult population is limited. A recent phase II trial (Yang et al, JCO 2022) has shown efficacy of proton-based CSI to treat non-small cell lung and breast cancer with LMD. We hypothesize that VBS-CSI utilizing volumetric modulated arc therapy (VMAT) could also effectively reduce dose to vertebral bodies and surrounding organs-at-risk (OARs), minimizing toxicity for adult patients with LMD and comparing favorably to proton-based CSI.

MATERIALS/METHODS

Consecutive patients with leptomeningeal disease received VMAT VBS-CSI, 30 Gy in 10 fractions, as a part of a prospective registry. Full VMAT arcs for the brain fields matched to two spine isocenters for the upper and lower spine were created utilizing limited posterior arcs. The PTV was created with margins of 3mm uniformly around the brain contour and 7mm around the spinal canal. To further decrease the vertebral body dose, an avoid entry and exit contour was created. This structure was a margin on the PTV anteriorly designed to carve dose out of the vertebral bodies while still maintaining coverage to the PTV. Acute toxicity data were collected using Common Terminology Criteria for Adverse Events (CTCAE) v5 and was defined as toxicity occurring within 30 days of treatment conclusion.

RESULTS

Ten adult patients were treated in this cohort. All patients completed radiation treatment. One patient experienced Grade 2 neutropenia with the remaining nine experiencing Grade 1 hematologic toxicity (three Grade 1 pancytopenia, six Grade 1 thrombocytopenia). Three patients experienced Grade 2 gastrointestinal toxicity (Grade 2 nausea, Grade 2 esophagitis, Grade 2 esophagitis/Grade 2 diverticulitis) with the remaining seven experiencing Grade 1 nausea. No patient experienced Grade 3+ toxicities in this cohort. One patient experienced a 5-day delay in systemic therapy initiation due to neutropenia; otherwise, all patients planned for systemic therapy started without delay.

CONCLUSION

VMAT VBS-CSI is an effective technique to reduce dose to surrounding OARs and vertebral bodies. In this study, VMAT VBS-CSI led to acceptable toxicity compared to patients treated with proton CSI on a phase 2 clinical trial. An NRG phase 3 clinical trial may be developed to evaluate the efficacy of proton-based CSI for patients with LMD. However, these data show how VMAT VBS-CSI may be an acceptable alternative for centers without proton therapy capabilities. Given its promising early results, future prospective evaluation of the technique is warranted.

A feasibility study of perioperative vitamin D supplementation in patients undergoing colorectal cancer resection

Background

Vitamin D supplementation improves colorectal cancer (CRC) survival outcomes in randomized trials. The aim of this study was to test the feasibility, safety and efficacy of vitamin D supplementation in the pre- and perioperative period in patients undergoing CRC surgery.

Methods

Patients were given 3200IU oral cholecalciferol (D3) per day perioperatively. Serial serum 25-hydroxyvitamin (25OHD) was measured by liquid chromatography tandem mass spectrometry and compared to untreated CRC controls. 25OHD and C-reactive protein (CRP) levels were compared using adjusted generalized linear mixed-effects models.

Results

A total of 122 patients underwent serial perioperative sampling, including 41 patients given high-dose perioperative supplementation. Supplementation was well-tolerated with no adverse or serious adverse events related to supplementation reported. Pre-operative supplementation increased 25OHD levels on the day of surgery (103.9 vs. 42.5 nmol/l, P = 8.2E-12). Supplementation increased 25OHD levels at all post-operative timepoints (P < 0.001) and attenuated the post-operative drop in 25OHD (46 vs. 24% drop, P = 3.0E-4). Rate of vitamin D peri-operative insufficiency was significantly less in those on supplementation (e.g., day 3-5, 14 vs. 84%, P = 1.41E-08), with multivariate modeling across all timepoints indicating a ∼59 nmol/l higher 25OHD compared to control patients (P = 3.7E-21). Post-operative CRP was lower in patients taking supplementation (e.g., day 3-5 timepoint; 129 vs. 81 mg/l, P = 0.04).

Conclusion

High dose pre-operative vitamin D supplementation is associated with higher perioperative 25OHD levels, lower rates of vitamin D insufficiency and reduced early post-operative CRP. Alongside published evidence for a beneficial effect of vitamin D on CRC survival outcomes, these novel findings provide strong rationale for early initiation of vitamin D supplementation after a diagnosis of CRC.

A multilevel, low literacy dual language intervention to promote colorectal cancer screening in community clinics in Florida: A randomized controlled trial

One of the largest disparities in cancer mortality in the United States occurs with colorectal cancer (CRC). The objectives of this multilevel two-arm intervention trial were to compare the efficacy of two interventions to promote CRC screening (CRCS) with fecal immunochemical test (FIT) and examine sociodemographic and psychosocial predictors of FIT screening. Individuals ages 50-75 (n = 326) who were not up-to-date with CRCS, could understand English or Spanish, and were at average CRC risk were recruited from two federally qualified health centers (FQHCs) in Florida. Prior to intervention, CRCS rates in the FQHCs were 27.1% and 32.9%, respectively. Study enrollment occurred April 2018-November 2019. System-level intervention components included leveraging electronic medical record (EMR) systems and delivering patient reminders. Participants were randomized to C-CARES (education+FIT) or C-CARES Plus (C-CARES+personalized coaching [for those not completing FIT within 90 days]). Primary outcome was completed FIT returned <1 year. Primary outcome analyses were performed using logistic regression. 225 participants completed FIT (69.0% [95% CI: 64.0-74.0%]), with no significant difference in FIT uptake by intervention arm (67.3% C-CARES Plus vs. 70.8% C-CARES; p = .49). FIT uptake was significantly higher among patients who received intervention materials in Spanish (77.2%) compared to those who received materials in English (63.2%, p < .01). The personalized coaching in the C-CARES Plus arm did not appear to provide added benefit beyond the C-CARES intervention. Multilevel approaches that include EMR prompts, reminders, FIT access, and provision of low-literacy, language-concordant education can support efforts to improved community clinics' CRCS rates. Future efforts should focus on repeat FIT screening. Trial registration: The trial was registered at ClinicalTrials.gov (NCT03906110).

290 ‘Save Blood' - Strategies to Reduce Inappropriate Routine Bloods Tests in a Surgical Department

Aim

To quantify the number of inappropriate blood tests in our 72-bed Surgical Department and identify strategies that reduce the number of unnecessary electronic blood test requests. This should reduce patient harm, demands on staff time, laboratory processing burden and financial expenditure.

Method

Each audit involved logging all blood tests for every surgical inpatient over two consecutive days. Upon reviewing the clinical records, it was decided whether tests were clinically indicated or ‘inappropriate’.

Following a baseline audit, three interventions were sequentially introduced over a one-year period, and the department re-audited after each: (1) educational sessions with junior medical staff and creation of ordering guidelines, (2) poster presentations, and (3) policing of requests by middle-grade doctors and removal of electronic blood test ordering bundles.

Results

Across the baseline audit to interventions 1–3, numbers of patients with at least one inappropriate test were recorded as 45/73 (62%), 51/63 (81%), 41/57 (72%), and 27/32 (84%), accruing totals of 363, 289, 303, and 149 inappropriate tests respectively. This gave an overall reduction in the rate of inappropriate blood tests per patient per day from a baseline of 0.9, to 0.9 then 0.8 to 0.5 with successive interventions.

Conclusions

Despite the innovation of electronic ordering systems enabling close audit of test schedules, inappropriate tests remain common. Educational sessions for junior doctors, written guidelines, and poster presentations had little influence on this.

However, rationalising electronic order bundles and involving senior doctors in decision-making, almost halved the rate of inappropriate tests. These more effective strategies will be disseminated throughout our hospital.

Preventative Cancer Screening Rates Among Uninsured Patients in Free Clinics: A Retrospective Cohort Study of Cancer Survivors and Non-cancer Survivors

Background

There is limited research on screening rates among uninsured cancer survivors. Uninsured cancer survivors are at higher risk of poorer health outcomes than the insured due to limited access to preventative screening for secondary cancers. This study examines the rates of surveillance and screening of uninsured cancer survivors and compares to uninsured patients without a cancer history seen in free clinics.

Methods

Data were collected retrospectively from electronic medical records and paper charts of patients from 10 free clinics between January 2016 and December 2018 in the Tampa Bay area. The prevalence of socioeconomic characteristics, cancer diagnoses, and screening practices were compared for cancer survivors and free clinic patients without a history of cancer. Study participants were determined to be eligible for cancer screenings based on the United States Preventive Services Task Force guidelines.

Results

Out of 13 982 uninsured patients frequenting free clinics between 2016 and 2018, 402 (2.9%) had a documented history of cancer. Out of the 285 eligible cancer survivors, 44 (15.4%) had completed age-appropriate colon cancer screening. Among the 170 female cancer survivors, 75 (44.1%) had completed breast cancer screenings, and only 5.9% (59/246) had completed cervical cancer screenings. After adjusting for age, gender, race, salary, employment status, and household size, cancer survivors were more likely to undergo colorectal cancer screening (OR: 3.59, 95% CI: 2.10–6.15) and breast cancer screening (OR: 2.13, 95% CI: 1.30–3.84) than patients without a cancer history. This difference was not seen for cervical cancer screening (OR: 0.99, 95% CI: .62–1.58).

Conclusions

Uninsured cancer survivors frequenting free clinics represent a unique population that is underrepresented in the medical literature. Our results suggest that uninsured survivors use screening services at higher rates when compared to uninsured patients without a reported cancer diagnosis. However, these rates are suboptimal when compared to national screening rates of insured cancer survivors.

425 The Impact Of COVID-19 On Hernia Surgery in The Lothian Region Of Scotland

Aim

The COVID-19 pandemic resulted in a lockdown in South East Scotland on the 23 March 2020. This had an impact on the volume of benign elective surgery able to be undertaken. The degree to which this reduced hernia surgery was unknown.

The aim of this study was to review the hernia surgery workload in the Lothian region of Scotland and assess the impact of COVID-19 on hernia surgery.

Method

The Lothian Surgical Audit database was used to identify all elective and emergency hernia operations over a six-month period from 23 March 2020, and for the same time period in 2019. Data was collected on age, gender, location of the hernia, type of hernia repair and whether elective or emergency operation.

Results

The number of hernia repairs reduced dramatically between 2019 and 2020 (570 versus 149). The majority of this can be explained by a reduction in elective operating (488 versus 87). There was, however, also a reduction in the numbers of hernias repaired as an emergency over the same study periods (82 to 62). Lockdown in 2020 had the biggest effect on elective incisional hernia repair (74 versus 2).

Conclusions

The COVID-19 pandemic has reduced both the number of elective and emergency hernia operations in 2020 compared to 2019. While the reduction in elective surgery has not resulted in an associated increase in emergency surgery over the study period, it is possible that if continuing reduced availability to elective hernia surgery continues in Lothian, the emergency hernia workload may increase.

Reported rationales for HPV vaccination vs. Non-vaccination among undergraduate and medical students in South Carolina

Objective: We sought to identify factors that influence Human Papillomavirus (HPV) vaccination rates in individuals at two higher education institutions in South Carolina (SC).Participants: We surveyed 1007 students with a mean age and standard deviation of 20.3 ± 3.3 from September 2018 to December 2018.Methods: Participants answered 13 questions, assessing HPV vaccination rates, demographics, and rationales for vaccination vs. non-vaccination.Results: Of 1007 respondents, 700 received HPV vaccination, 165 were unvaccinated, 75 received partial vaccination and 138 were uncertain. Commonalities in HPV vaccination existed between females (p = 0.037), individuals who received standard childhood vaccinations (p = 0.04), and those not native-born in SC (p < 0.001). Of non-vaccinated individuals, 37% "never thought about vaccination," 32% did not perceive a need for vaccination, and 31% reported vaccine safety as reasons for not receiving the vaccine.Conclusions: Promotion of HPV vaccination may benefit from targeting SC natives, males, and individuals who are under-vaccinated or unvaccinated.

Low plasma vitamin D is associated with adverse colorectal cancer survival after surgical resection, independent of systemic inflammatory response

OBJECTIVE

We assessed the effect of surgical resection of colorectal cancer (CRC) on perioperative plasma vitamin D (25OHD) and C-reactive protein (CRP) level. We investigated the relationship between circulating vitamin D level and CRC survival.

DESIGN

We sequentially sampled 92 patients undergoing CRC resection, and measured plasma 25OHD and CRP. For survival analyses, we assayed 25OHD and CRP in two temporally distinct CRC patient cohorts (n=2006, n=2100) and investigated the association between survival outcome, circulating vitamin D and systemic inflammatory response.

RESULTS

Serial sampling revealed a postoperative fall (mean 17.3 nmol/L; p=3.6e-9) in plasma 25OHD (nadir days 1-2). CRP peaked 3-5 days postoperatively (143.1 mg/L; p=1.4e-12), yet the postoperative fall in 25OHD was independent of CRP. In cohort analyses, 25OHD was lower in the 12 months following operation (mean=48.8 nmol/L) than preoperatively (54.8 nmol/L; p=1.2e-5) recovering after 24 months (52.2 nmol/L; p=0.002). Survival analysis in American Joint Committee on Cancer stages I-III demonstrated associations between 25OHD tertile and CRC mortality (HR=0.69; 95% CI 0.46 to 0.91) and all-cause mortality (HR=0.68; 95% CI 0.50 to 0.85), and was independent of CRP. We observed interaction effects between plasma 25OHD and rs11568820 genotype (functional VDR polymorphism) with a strong protective effect of higher 25OHD only in patients with GG genotype (HR=0.51; 95% CI 0.21 to 0.81). We developed an online tool for predicted survival (https://apps.igmm.ed.ac.uk/mortalityCalculator/) that incorporates 25OHD with clinically useful predictive performance (area under the curve 0.77).

CONCLUSIONS

CRC surgery induces a fall in circulating 25OHD. Plasma 25OHD level is a prognostic biomarker with low 25OHD associated with poorer survival, particularly in those with rs11568820 GG genotype. A randomised trial of vitamin D supplementation after CRC surgery has compelling rationale.

A Systematic Review of U.S.-Based Colorectal Cancer Screening Uptake Intervention Systematic Reviews: Available Evidence and Lessons Learned for Research and Practice

Background: We examined colorectal cancer screening (CRCS) intervention effectiveness, through the effect sizes associated with: (1) screening modality, (2) intervention level (e.g., client-directed), and (3) intervention component (e.g. client reminders) within published CRCS intervention systematic reviews (SRs).

Methods: A search of peer-reviewed CRCS SRs that were written in English was employed utilizing five databases: CINAHL, Cochrane Library, rTIPS, PubMed, and PsycINFO EBSCOHOST. SRs that included CRCS interventions with a randomized controlled trial, quasi-experimental, or single arm design were eligible. Data on effect sizes by screening modality, intervention level, and intervention component were extracted and synthesized.

Results: There were 16 eligible CRCS intervention SRs that included 116 studies published between 1986 and 2013. Reviews organized data by CRCS screening modality, or intervention component. Effect size reporting varied by format (i.e., ranges, medians of multiple studies, or effect size per study), and groupings of modalities and components. Overall, the largest effect sizes were for studies that utilized a combination of colonoscopy, fecal occult blood test (FOBT), and sigmoidoscopy as screening options (16–45 percentage point difference).

Conclusions: Evidence suggests that CRCS interventions which include a combination of screening modalities may be most effective. This is the first SR to examine effect sizes of published CRCS SRs. However, because some SRs did not report effect sizes and there were tremendous variability reporting formats among those that did, a standard reporting format is warranted. Synthesizing findings can contribute to improved knowledge of evidence-based best-practices, direct translation of findings into policy and practice, and guide further research in CRCS.

Comorbidities, risk, and socioeconomic factors of uninsured cancer survivors

Cancer patients can be well-connected to resources during treatment but become lost to follow-up and subsequently may receive treatment in free clinics for chronic morbidities. Few studies have examined outcomes for uninsured patients with cancer histories in free clinics, but research examining socioeconomic determinants emphasizes poor cancer outcomes for patients with lower socioeconomic statuses (SES).Demographic data and chronic disease measures were extracted from medical charts of patients treated in 8 free clinics in 2016 in Tampa Bay. Descriptive statistics and Pearson correlation coefficients were used to demonstrate relationships between socioeconomic factors, cancer diagnoses, and comorbidities. Charlson Comorbidity Index (CCI) was used to assess mortality risk and severity of disease burden.The histories of 4804 uninsured patients were evaluated, identifying 86 (1.7%) as having had cancer. They were predominantly female (65.1%) and significantly older than those without cancer histories. Average duration from initial diagnosis was approximately 8.53 years (standard deviation [SD] 7.55). Overall, cancer patients had higher CCI scores (3.04 [1.928 SD] versus 0.90 [1.209 SD]; P <.001); thus reflecting more weighted comorbidities than patients without cancer (P <.001). Other factors of chronic disease including obesity and substance abuse correlated with cancer history.Among uninsured patients, those with cancer histories had greater mortality risk by CCI than those without. Chronic conditions such as diabetes, cerebrovascular disease, and chronic pulmonary disease existed in patients with cancer histories, affecting their mortality risk. Uninsured patients with a history of cancer are in greater need for chronic disease management and prevention.

Autologous breast reconstruction using the immediately lipofilled extended latissimus dorsi flap

BACKGROUND

The latissimus dorsi flap is a popular choice for autologous breast reconstruction. To dramatically improve volume, we report our experience of using the immediately lipofilled extended latissimus dorsi (ELD) flap and show it as a valid option for autologous breast reconstruction.

METHODS

Patients undergoing the procedure between December 2013 and June 2016 were included. Demographic, clinical and operative factors were analysed, together with in-hospital morbidity and duration of postoperative hospital stay.

RESULTS

A total of 71 ELD flaps with immediate lipofilling were performed. Forty-five reconstructions were immediate and the remaining 26 delayed. Median (range) volume of autologous fat injected immediately was 171 ml (40-630 ml). Contralateral reductions were performed in 25 patients with the median reduction volume 185 g (89-683 g). Median duration of admission was 6.5 (3-18) days and patients were followed up for 12 months (1-37). Three total flap failures occurred and had to be excised (4%). One haematoma occurred requiring drainage (1%). Signs of infection requiring intravenous antibiotics occurred in five patients (7%). In 5 patients wound dehiscence occurred, and only two of these required resuturing (3%). In total, 7 patients developed a seroma requiring repeated drainage (10%). Three reconstructions experienced mild mastectomy flap necrosis with no needing reoperation (4%).

CONCLUSIONS

Our experience represents the largest series to date and shows that in carefully selected patients the technique is safe, can avoid the requirement for implants, and has the potential to streamline the reconstructive journey.

In vivo evaluation of safety of nanoporous silicon carriers following single and multiple dose intravenous administrations in mice

Porous silicon (pSi) is being extensively studied as an emerging material for use in biomedical applications, including drug delivery, based on the biodegradability and versatile chemical and biophysical properties. We have recently introduced multistage nanoporous silicon microparticles (S1MP) designed as a cargo for nanocarrier drug delivery to enable the loaded therapeutics and diagnostics to sequentially overcome the biological barriers in order to reach their target. In this first report on biocompatibility of intravenously administered pSi structures, we examined the tolerability of negatively (-32.5±3.1mV) and positively (8.7±2.5mV) charged S1MP in acute single dose (10(7), 10(8), 5×10(8) S1MP/animal) and subchronic multiple dose (10(8) S1MP/animal/week for 4 weeks) administration schedules. Our data demonstrate that S1MP did not change plasma levels of renal (BUN and creatinine) and hepatic (LDH) biomarkers as well as 23 plasma cytokines. LDH plasma levels of 145.2±23.6, 115.4±29.1 vs. 127.0±10.4; and 155.8±38.4, 135.5±52.3 vs. 178.4±74.6 were detected in mice treated with 10(8) negatively charged S1MP, 10(8) positively charged S1MP vs. saline control in single and multiple dose schedules, respectively. The S1MPs did not alter LDH levels in liver and spleen, nor lead to infiltration of leukocytes into the liver, spleen, kidney, lung, brain, heart, and thyroid. Collectively, these data provide evidence of a safe intravenous administration of S1MPs as a drug delivery carrier.

Measurements of catecholamine-mediated apoptosis of immunocompetent cells by capillary electrophoresis

Single cell analysis with capillary electrophoresis, a technique capable of detecting zeptomole quantities (10(-21) mole) of neurochemical species, has been used to demonstrate that lymphocytes are capable of active synthesis of dopamine and norepinephrine. Exposure of lymphocytes to catecholamines at concentrations as low as 10 nM leads to decreased proliferation and differentiation, e.g. interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and immunoglobulin (Ig). In addition, both inhibition of dopamine uptake with nomifensine and inhibition of packing of catecholamines into vesicles with tetrabenazine, results in significantly lower levels of dopamine and norepinephrine (p < 0.01 and p < 0.05, respectively). The catecholamine-dependent inhibition of T- and B-lymphocyte activity is mediated via an induction of a Bcl-2/Bax and Fas/FasL involved apoptosis. These findings indicate a novel mechanism for regulation of lymphocyte activity in the central nervous system, whereby elevated regional levels of catecholamines might lead to the immunoprivilege of the brain.

Amphetamine redistributes dopamine from synaptic vesicles to the cytosol and promotes reverse transport

Whether amphetamine acts principally at the plasma membrane or at synaptic vesicles is controversial. We find that d-amphetamine injection into the Planorbis giant dopamine neuron causes robust dopamine release, demonstrating that specific amphetamine uptake is not required. Arguing for action at vesicles, whole-cell capillary electrophoresis of single Planorbis dopamine neurons shows that amphetamine reduces vesicular dopamine, while amphetamine reduces quantal dopamine release from PC12 cells by > 50% per vesicle. Intracellular injection of dopamine into the Planorbis dopamine neuron produces rapid nomifensine-sensitive release, showing that an increased substrate concentration gradient is sufficient to induce release. These experiments indicate that amphetamine acts at the vesicular level where it redistributes dopamine to the cytosol, promoting reverse transport, and dopamine release.

Discovery of endogenous catecholamines in lymphocytes and evidence for catecholamine regulation of lymphocyte function via an autocrine loop

Evidence has been obtained that catecholamines and their metabolites are present in single lymphocytes and extracts of T- and B-cell clones by use of capillary electrophoresis with electrochemical detection. Pharmacological inhibition of tyrosine hydroxylase reduces observed catecholamine levels, suggesting catecholamine synthesis by lymphocytes. Intracellular dopamine levels are shown to be increased by extra-cellular dopamine, suggesting a cellular-uptake mechanism. Furthermore, incubation with either dopamine or L-dihydroxyphenylalanine, a precursor of dopamine, results in a dose-dependent inhibition of lymphocyte proliferation and differentiation. Together, these results suggest the presence of an autocrine loop whereby lymphocytes down-regulate their own activity.

Hordenine: pharmacology, pharmacokinetics and behavioural effects in the horse

Hordenine is an alkaloid occurring naturally in grains, sprouting barley, and certain grasses. It is occasionally found in post race urine samples, and therefore we investigated its pharmacological actions in the horse. Hordenine (2.0 mg/kg bodyweight [bwt]) was administered by rapid intravenous (iv) injection to 10 horses. Typically, dosed horses showed a flehmen response and defecated within 60 secs. All horses showed substantial respiratory distress. Respiratory rates increased about 250 per cent and heart rates were approximately double that of resting values. All animals broke out in a sweat shortly after iv injection, but basal body temperature was not affected. These effects were transient, and the animals appeared normal within 30 mins of dosing. Treated horses were tested in a variable interval responding apparatus 30 mins after dosing and no residual stimulation or depressant effects of hordenine were apparent. Animals dosed orally with 2.0 mg/kg bwt of hordenine showed no changes in heart rate, respiratory rate, basal body temperature or behaviour. After iv injection of hordenine, (2.0 mg/kg bwt) plasma reached a maximum value of about 1.0 micrograms/ml, and declined thereafter in a biexponential fashion. Kinetics of plasma concentration satisfied the concept of a two compartment open system, with an alpha-phase half-life of about 3 mins, and a beta-phase half-life of about 35 mins. Total urinary concentrations of hordenine (free and conjugated) peaked at about 400 micrograms/ml, and then declined exponentially to background levels by 24 h after dosing.(ABSTRACT TRUNCATED AT 250 WORDS)

Infant mortality increase despite high access to tertiary care: an evolving relationship among infant mortality, health care, and socioeconomic change

In this study, the determinants of an apparent increase in the infant mortality rate of an urban population with high access to tertiary neonatal care are reviewed. For a 4-year period (1980 to 1983), all infant deaths (n = 422) of the 32,329 births to residents of the City of Boston were analyzed through linked vital statistics data and a review of medical records. A significant increase in the infant mortality rate occurred in 1982 due to increases in three components of the infant mortality rate: the birth rate of very low birth weight infants (less than 1,500 g), the neonatal mortality rate of normal birth weight infants (greater than or equal to 2,500 g), and the mortality rate of infants dying during the postneonatal period (28 to 365 days). These increases were associated with inadequate levels of prenatal care. Although transient, the impact of the observed alterations in these infant mortality rate components was enhanced by a more long-standing phenomenon: the stabilization of mortality rates for low birth weight infants. This stabilization allowed the increases in other component rates to be expressed more fully than in previous years. In this report a mechanism is shown whereby fully regionalized neonatal care ultimately may confer to the infant mortality rate a heightened sensitivity to socioeconomic conditions and levels of adequate prenatal care.

Interactions of asbestos-activated macrophages with an experimental fibrosarcoma

Supernatants from in vivo asbestos-activated macrophages failed to show any cytostatic activity against a syngeneic fibrosarcoma cell line in vitro. UICC chrysotile-induced peritoneal exudate cells also failed to demonstrate any growth inhibitory effect on the same cells in Winn assays of tumor growth. Mixing UICC crocidolite with inoculated tumor cells resulted in a dose-dependent inhibition of tumor growth; this could, however, be explained by a direct cytostatic effect on the tumor cells of high doses of crocidolite, which was observed in vitro.

Neuronal Mechanisms Underlying Control of Sound Production in a Cricket: Acheta Domesticus

1. The singing of the cricket Acheta domesticus has been studied with a view to examining the neuronal control mechanisms underlying the sound production.

2. Electrical activity was recorded from the muscles responsible for wing opening and closing during singing in intact, freely-moving crickets.

3. Three kinds of song which are both structurally distinct and clearly different in behavioural context were studied in detail: calling, aggression and courtship.

4. Each song is composed of a group of pulses of sound and each pulse corresponds to a single wing-closing movement. The songs differ only in regard to either the number of pulses in a group, or the loudness of the pulses.

5. The opening is caused by the tergosternal muscles receiving a brief burst of excitatory nerve impulses. Extra impulses, leading to extra wide opening, occur before loud sounds.

6. The closing movement is initiated by the first and second basalar and subalar muscles acting synergistically. The force, but not the velocity, of the closing stroke is increased by a late burst of activity in the indirectly acting dorsal longitudinal muscles, leading to louder sound.

7. Weak pulses are the result of (probably) only S axons firing. When F axons fire in addition loud sounds result.

8. During courtship songs the sound pulses are mainly weak and a large number of pulses occur consecutively.

9. The kind of neuronal machinery required to produce the observed output is considered theoretically, and a tentative simple scheme proposed.

10. It is not necessary to postulate separate neuronal centres for each sound, and a small number of neurons could, in principle, provide the underlying control of the different kinds of cricket song.