Overview of the Langmuir probe system on the Mega Ampere Spherical Tokamak (MAST) Upgrade

A detailed description of the Langmuir probe system on Mega Ampere Spherical Tokamak Upgrade is presented. The system features 850 tile-embedded probes and 40 bespoke electronic modules that each have the capability to drive and acquire data from up to 16 probes in a time-multiplexed manner. The system provides spatiotemporal-resolved measurements (1 cm and ∼1 ms, respectively) in the divertor region of ion saturation current, electron temperature, and floating potential. The standard interpretation of current-voltage (IV) characteristics is to apply a four-parameter fit, based on unmagnetized probe theory, which includes a linear model for the ion saturation region. To mitigate the effect of the magnetic field, analysis is restricted to the region of the IV characteristic, which is sensitive to only the tail of the electron energy distribution function.

Fission chamber data acquisition system for neutron flux measurements on the Mega-Amp Spherical Tokamak Upgrade

Neutron flux measurements are important in fusion devices for both safety requirements and physics studies. A new system has been built for the Mega-Amp Spherical Tokamak Upgrade (MAST Upgrade) that provides neutron count, DC, and Campbell mode measurements for a 1 µs period at 1 MHz. The acquisition system uses a Red Pitaya board to sample current from two fission chambers mounted on the side of the MAST-U vessel. The system-on-chip design of the Zynq-7020 on the Red Pitaya also allows a web server implementation using Flask for data retrieval and diagnostic configuration over the MAST Upgrade network.

Disruption of CCR5 signaling to treat COVID-19-associated cytokine storm: Case series of four critically ill patients treated with leronlimab

Coronavirus disease 2019 (COVID-19) is associated with considerable morbidity and mortality. The number of confirmed cases of infection with SARS-CoV-2, the virus causing COVID-19 continues to escalate with over 70 million confirmed cases and over 1.6 million confirmed deaths. Severe-to-critical COVID-19 is associated with a dysregulated host immune response to the virus, which is thought to lead to pathogenic immune dysregulation and end-organ damage. Presently few effective treatment options are available to treat COVID-19. Leronlimab is a humanized IgG4, kappa monoclonal antibody that blocks C–C chemokine receptor type 5 (CCR5). It has been shown that in patients with severe COVID-19 treatment with leronlimab reduces elevated plasma IL-6 and chemokine ligand 5 (CCL5), and normalized CD4/CD8 ratios. We administered leronlimab to 4 critically ill COVID-19 patients in intensive care. All 4 of these patients improved clinically as measured by vasopressor support, and discontinuation of hemodialysis and mechanical ventilation. Following administration of leronlimab there was a statistically significant decrease in IL-6 observed in patient A (p=0.034) from day 0–7 and patient D (p=0.027) from day 0–14. This corresponds to restoration of the immune function as measured by CD4+/CD8+ T cell ratio. Although two of the patients went on to survive the other two subsequently died of surgical complications after an initial recovery from SARS-CoV-2 infection.

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Leronlimab is a monoclonal antibody in clinical trials to treat the cytokine storm.

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Critically ill patients received leronlimab through compassionate use and had remarkable recoveries measured objectively.

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The CCR5 receptor is important in recruiting inflammatory cells mainly T cells and macrophages.

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Leronlimab disrupted this signal and may have been responsible for restoration of the immune system, improved survival and decrease in IL-6.

Albuminuria: when urine predicts kidney and cardiovascular disease

Albuminuria is common. Traditionally considered a precursor to diabetic nephropathy, it has now been directly linked to adverse cardiovascular outcomes and death, independent of other risk factors. In this review, we compare the measures of albuminuria, examine the evidence linking it to renal failure, cardiovascular disease, and death, and provide recommendations for its testing and management.

Persistence and adherence to disease modifying drugs among patients with multiple sclerosis

OBJECTIVE

This retrospective database study aimed to evaluate the adherence of multiple sclerosis (MS) patients on immunomodulatory treatments using claims data, and to identify differences between compliance and persistency measurements in the context of this disease.

METHODS

Continuously enrolled MS patients treated with subcutaneous IFNbeta-1b (Betaseron * ), subcutaneous IFNbeta-1a (Rebif dagger ), intramuscular IFNbeta-1a (Avonex double dagger ), and subcutaneous glatiramer acetate (Copaxone section sign ).) were identified from the PharMetrics patient-centric database, and all information related to patient demographics and pharmacy claims for the drugs of interest were extracted.

OUTCOME MEASURES

The main outcomes were treatment switches and discontinuations for patients initiated on the drugs of interest. Various compliance and persistency metrics including the proportion of days covered, treatment prevalence at 6-monthly time points after initiation, and the continuous time on drug were also examined.

RESULTS

A total of 6134 MS patients were started on one of the four drugs of interest. The number of patients switching or discontinuing therapy rose over the study period. The proportion of patients switching was similar between study drugs, by the different metrics, with the highest switch rates for subcutaneous IFNbeta-1b and the lowest for subcutaneous glatiramer acetate. Discontinuation rates were highest for subcutaneous IFNbeta-1b and lowest for intramuscular IFNbeta-1a. Regression models showed that intramuscular IFNbeta-1a and subcutaneous IFNbeta-1a had similar and higher persistency compared to subcutaneous IFNbeta-1b and subcutaneous glatiramer acetate.

CONCLUSIONS

Although treatment switching and discontinuation is common in MS patients, there is some noticeable variability between drugs and across measures of persistency and adherence. Also, claims data do not allow distinguishing between clinical patterns of MS, direct estimation of disease severity and observation of care that occurs outside of insurance coverage, and results need to be cautiously interpreted. The compliance to the various MS drugs was 80% or higher at all times for all four drugs. The highest rate of treatment persistency existed in the intramuscular IFNbeta-1a initiator group, while subcutaneous IFNbeta-1b was associated with a significantly lower persistence (p < 0.0001).

Healthcare resource utilization following switch or discontinuation in multiple sclerosis patients on disease modifying drugs

OBJECTIVE

The objective of this study was to explore the cost and utilization in the period following discontinuations or switches of disease modifying drugs (DMDs) for patients with multiple sclerosis (MS). Secondary objectives included an assessment of the time to switch or discontinuation from index DMD treatment.

METHODS

Cases were defined as a billed MS diagnosis in continuously enrolled patients initiated with interferon-beta1a IM, interferon-beta1b SC, glatiramer acetate, and interferon-beta1a SC found in the PharMetrics Patient-Centric Database. Information on patient demographics, diagnoses, procedures, pharmacy-dispensed drugs, and costs was extracted; reasons for discontinuation and expenses outside of the healthcare system were not available. Treatment discontinuations and switches between study drugs were defined using pharmacy prescription patterns and analyzed by descriptive and regression methods. The non-pharmacy medical costs in the 18 months following switching or discontinuation were compared to the costs in a randomly selected similar period for those patients who did not switch or discontinue these agents.

RESULTS

A total of 5,772 MS patients were continuously enrolled and were treated with one or more of the four drugs of interest, and about half of these patients switched drugs or discontinued treatment for at least 90 days. Patients initiated with interferon-beta1b SC were more likely to discontinue treatment compared to interferon-beta1a IM users. Non-pharmaceutical medical costs were highest for those switching treatments followed by those discontinuing DMDs in the 18 months following a switch or discontinuation, compared to persistent users of these drugs. Interferon beta1b SC initiators had higher costs following changes or discontinuations, while glatiramer acetate and interferon-beta1a SC users had lower subsequent costs compared to interferon-beta1a IM users.

LIMITATIONS

Unfortunately, the reasons for stopping the initial treatment cannot be determined from analysis of an administrative claims database. Also, the MS cases followed in this analysis are billing diagnostic events unconfirmed through a review of medical records or other data sources. The results are unstratified in terms of severity and thus while treatment patterns may vary for patients with different types of MS (e.g., progressive vs. relapsing-remitting), this cannot be examined in this analysis.

CONCLUSION

Changing or discontinuing DMDs is common among MS patients and is associated with higher non-pharmaceutical medical costs that vary based on the initiating drug and other demographics characteristics.

Comparison of morphine concentration-time profiles following intravenous and intranasal diamorphine in children

BACKGROUND

Current best practice for treating acute severe pain in children is to administer intravenous or intranasal opioid. Intranasal diamorphine offers less traumatic analgesia than the potentially difficult and distressing intravenous route. However, there has been no direct comparison of intranasal and intravenous diamorphine nor are there pharmacokinetic data for intranasal diamorphine in children.

OBJECTIVE

To compare plasma morphine concentration-time profiles following intranasal and intravenous diamorphine administration.

DESIGN

Observational.

SETTING

A&E department in a city-centre paediatric teaching hospital.

PATIENTS

Children, aged 3-13 years, with isolated limb fracture.

INTERVENTIONS

An intravenous catheter was sited and baseline blood taken. The first 12 children received intravenous diamorphine (0.1 mg/kg), and the subsequent 12 intranasal diamorphine (0.1 mg/kg) in 0.2 ml sterile water drops. Subsequent samples were taken at 2, 5, 10, 20, 30 and 60 min.

MEASUREMENTS

Plasma morphine radioimmunoassay.

RESULTS

Peak plasma morphine concentrations were higher (median 109 vs 36 nmol/l), and occurred earlier (median 2 vs 10 min), with greater area under the curve (3761 vs 1794 nmol/l/h) following intravenous compared to intranasal diamorphine (all p<0.001, Mann-Whitney U test). Higher plasma concentrations at 60 min (47 vs 32 nmol/l) were also observed following intravenous diamorphine (p = 0.01, Mann-Whitney U test).

CONCLUSIONS

Our evidence supports the wider use of diamorphine administration by nasal drops in children, as it shows that adequate plasma levels of morphine are usually achieved. However, we demonstrated significantly attenuated and delayed peak plasma morphine levels with lower levels at 1 h with intranasal compared with intravenous diamorphine.

Neonatal blood pressure waves are associated with surges of systemic noradrenaline

Neonatal blood pressure (BP) waves have been linked to neonatal illness. We investigated plasma levels of vasoactive hormones when BP waves were observed. Peak and trough noradrenaline levels correlated with mean BP (p = 0.028). There was no relationship to adrenaline, dopamine or endothelin levels.

Feasibility of using a large Clinical Data Warehouse to automate the selection of diagnostic cohorts

Data from Clinical Data Warehouses (CDWs) can be used for retrospective studies and for benchmarking. However, automated identification of cases from large datasets containing data items in free text fields is challenging. We developed an algorithm for categorizing pediatric patients presenting with respiratory distress into Bronchiolitis, Bacterial pneumonia and Asthma using clinical variables from a CDW. A feasibility study of this approach indicates that case selection may be automated.

Scurvy identified in the emergency department: a case report

Scurvy, caused by a lack of Vitamin C in the diet, is thought to occur only sporadically in developed countries. The signs and symptoms are diverse but generally follow a predictable progression most striking for their hemorrhagic component, particularly of the skin, gums, and joints. We report a case of scurvy in an elderly, alcoholic woman. The diagnosis was contemplated based on dermatologic findings and a dietary history. All symptoms resolved within 10 days of oral ascorbic acid supplementation. Patients most at risk for developing scurvy include food faddists, the isolated elderly, and the mentally ill.

Loss of growth inhibitory effects of retinoic acid in human breast cancer cells following long-term exposure to retinoic acid

Although retinoids are known to be inhibitory to breast cancer cell growth, a key remaining question is whether they would remain effective if administered long-term. We describe here the long-term effects of all- trans retinoic acid on two oestrogen-dependent human breast cancer cell lines MCF7 and ZR-75-1. Although both cell lines were growth inhibited by retinoic acid in the short-term in either the absence or the presence of oestradiol, prolonged culture with 1 microM all- trans retinoic acid resulted in the cells acquiring resistance to the growth inhibitory effects of retinoic acid. Time courses showed that oestrogen deprivation of the cell lines resulted in upregulation of the basal non-oestrogen stimulated growth rate such that cells learned to grow at the same rate without as with oestradiol, but the cells remained growth inhibited by retinoic acid throughout. Addition of 1 microM all- trans retinoic acid to steroid deprivation conditions resulted in reproducible loss of growth response to both retinoic acid and oestradiol, although the time courses were separable in that loss of growth response to retinoic acid preceded that of oestradiol. Loss of growth response to retinoic acid did not involve loss of receptors, ER as measured by steroid binding assay or RARalpha as measured by Northern blotting. Function of the receptors was retained in terms of the ability of both oestradiol and retinoic acid to upregulate pS2 gene expression, but there was reduced ability to upregulate transiently transfected ERE- and RRE-linked reporter genes. Despite the accepted role of IGFBP3 in retinoic acid-mediated growth inhibition, progression to retinoic acid resistance occurred irrespective of level of IGFBP3, which remained high in the resistant MCF7 cells. Measurement of AP1 activity showed that the two cell lines had markedly different basal AP1 activities, but that progression to resistance was accompanied in both cases by a lost ability of retinoic acid to reduce AP1 activity. These results warn of potential resistance which could arise on long-term treatment with retinoic acid in a clinical situation and echo the problems of progression to endocrine resistance. It seems that whatever the constraints imposed on growth, these cells have a remarkable ability to escape from growth inhibition. However, the ability of retinoic acid to delay progression to oestrogen resistance is encouraging for endocrine therapy, and the concentration-dependence of retinoic acid resistance suggests that progression is not absolute but could be manipulated by dose.

Dissociation of osmoregulation from plasma arginine vasopressin levels following thermal injury in childhood

Although the syndrome of inappropriate anti-diuretic hormone secretion has been recognised as a complication associated with burn and other trauma in adults, relatively little is known about its incidence in children. The objective of this study was to investigate whether it is a complication associated with burn injury in children. Plasma and urine levels of arginine vasopressin (anti-diuretic hormone), sodium and osmolality were measured in samples collected from 16 burn-injured children admitted to the burns unit of the regional children's hospital. No significant correlations were found between plasma vasopressin and plasma sodium or osmolality levels, but there were significant correlations between plasma vasopressin and urine osmolality, 36 (r=0.74, p=0. 009), 60 (r=0.92, p=0.000) and 84 h (r=0.84, p=0.001) after admission, respectively. There were also significant correlations between plasma sodium and plasma osmolality, 24 (r=0.7, p=0.005), 36 (r=0.57, p=0.04) and 84 h (r=0.84, p=0.004) after admission. The data suggest dissociation between the osmolar control of vasopressin secretion and vasopressin levels after burn injury in children, but do not support the incidence of inappropriate secretion of antidiuretic hormone.

Effects of dexamethasone treatment on bone and collagen turnover in preterm infants with chronic lung disease

Dexamethasone is used commonly in the treatment of chronic lung disease of prematurity, but there are concerns about possible deleterious effects on growth and bone. Our aim in this study was to examine the effects of dexamethasone treatment on bone and collagen turnover in preterm infants. Bone-specific alkaline phosphatase, the C-terminal propeptide of type I collagen (PICP, reflecting whole-body type I collagen synthesis), and the N-terminal propeptide of type III procollagen (P3NP, reflecting soft tissue collagen turnover), together with the C-terminal telopeptide of type I collagen (ICTP), urinary pyridinoline (Pyd), and deoxypyridinoline (all markers of collagen breakdown) were measured at weekly intervals over the first 12 wk of life in 14 preterm infants with chronic lung disease treated with dexamethasone. Results were expressed as SD scores relative to preterm control infants not treated with dexamethasone. PICP, P3NP, ICTP, and Pyd all showed marked decreases (-2.1 to -3.7 SD scores) during the first week of treatment (p < 0.001), returning to pretreatment levels after stopping dexamethasone. In the group as a whole, these collagen markers were negatively correlated with dexamethasone dose (p < 0.0001); negative correlations were also seen in most individual babies, although the slopes of individual regression lines varied by a factor of 2. Weight gain at 12 wk was correlated with PICP, expressed as the mean SD score over 12 wk for each baby, (r = 0.69, p < 0.01) but not with other markers or cumulative dose of dexamethasone. We conclude that dexamethasone markedly suppressed collagen turnover in preterm infants in a dose-dependent fashion, although some babies were more affected than others. The degree of suppression of type I collagen synthesis was a strong independent predictor of overall weight gain over the first 12 wk of life.

Bone and collagen markers in preterm infants: relationship with growth and bone mineral content over the first 10 weeks of life

In a longitudinal study of 25 preterm infants, we have examined the relationship of bone-specific alkaline phosphatase (ALP), C-terminal propeptide of type I collagen (PICP), N-terminal propeptide of type III procollagen (P3NP), C-terminal telopeptide of type I collagen, urinary pyridinoline (Pyd) and deoxypyridinoline (Dpd), with rates of gain in weight, length, and lower leg length and with bone mineral content (BMC), all measured at weekly intervals over the first 10 wk of life. Concentrations of all collagen markers were 10-fold higher than in older children. Each marker showed a distinctive pattern of postnatal change, with early increases in PICP and P3NP and decreases in ICTP reflecting postnatal growth. Once markers had reached a plateau during weeks 4-10, P3NP was positively correlated, whereas Pyd and Dpd were negatively correlated with rate of weight gain (r = +0.44, -0.46, and -0.40, respectively, p < 0.05). P3NP was also positively correlated with overall linear growth (r = +0.44, p < 0.05). PICP was strongly correlated with mean BMC (r = +0.63,p < 0.01) and with total BMC attained by the end of the study period (r = +0.81, p < 0.001). Bone ALP was positively correlated with the rate of bone mineral accretion (r = +0.55, p = 0.01). We conclude that the marker of soft-tissue collagen formation, P3NP, is a good marker for overall ponderal and linear growth in preterm infants, whereas the markers of collagen breakdown, Pyd and Dpd, have inverse relationships with weight gain. The osteoblast markers, PICP and bone ALP, seem to be good surrogate markers for bone mineralization in preterm infants. Markers may provide information on whole-body turnover of bone and collagen that is complementary to traditional physical measures of growth and bone mineralization.

Systemic hormonal, electrolyte, and substrate changes after non-thermal limb injury in children

Relatively little is known regarding the hormonal changes after injury in children. Adult protocols are often applied to children, although the latter often have different physiological responses to trauma. Twenty children with an angulated displaced fracture of the radius and/or ulna (injury severity score 9) were studied prospectively for changes in adrenaline, noradrenaline, cortisol, angiotensin II, arginine vasopressin, urea, electrolytes, and glucose. Two blood samples were taken: one an arrival at the accident and emergency department and one preoperatively several hours later. There were marked increases in adrenaline, noradrenaline, cortisol, and arginine vasopressin above the normal range. Five (25%) cases demonstrated greater early increases in adrenaline than those reported for adult injuries of similar severity. Early hypokalaemia in four cases had corrected towards normal within a few hours, without potassium supplementation.

A COMPARISON OF DIFFERENT METHODS OF MEASURING FAT MASS IN HEALTHY INDIANS WITH A WIDE BMI RANGE

The prediction of fat mass from the measurement of bioelectricai impedance has gained popularity because of the ease of performing the measurement. However, the prediction equation used in this method could be specific for a distribution of body size. This study tested the prediction of fat mass in Indian, by the use of an equation based on bioelectrical impedance, which had earlier been generated on a group of low body mass index (BMI 18.15 ± 2.07 kg/m2) Indians. The impedance method was tested against a standard skinfold method based on the sum of four skinfolds, in a group of 68 Indian males with a large range of BMI (16-26 kg/m2'). The subject were tested as a single group, and were also stratified into four groups based on their BMI, with ranges of BMI between, 15.0-17.9, 18.0-20.9, 21.0-23.9, and > 24.0. The mean difference between the estimates of fat mass from the two methods was low in the lowest body mass index (BMI) group (0.91 ± 2.00 kg), with the impedance equation over-estimating the fat mass in all groups. This suggests that the impedance equation should be used with caution in groups whose BMI is above 21. The distribution of the skinfold thickness revealed that the thickness of the supraihac skinfold showed the most linear and greatest increment, as the BMI increased across the groups, indicating that it is probably the best single indicator of the fat mass, among the individual skinfolds.

Effects of intensive chemotherapy on bone and collagen turnover and the growth hormone axis in children with acute lymphoblastic leukemia

To investigate the effects of disease and intensive chemotherapy on bone turnover and growth in children with acute lymphoblastic leukemia (ALL), a longitudinal prospective study was carried out in 22 children, aged 1.2-13.5 yr, enrolled in the Medical Research Council-funded randomized trial of childhood ALL treatment in the UK. We measured lower leg length and markers of bone formation [bone alkaline phosphatase (ALP) and procollagen type I C-terminal propeptide (PICP)], bone resorption [pyridinoline, deoxypyridinoline, and carboxyl-terminal telopeptide of type I collagen (ICTP)], soft tissue turnover [procollagen type III N-terminal propeptide (P3NP)], and the GH axis [IGF-I, IGF-binding protein-3 (IGFBP-3), IGFBP-2, and urinary GH] at 1- to 4-week intervals from diagnosis to week 27 of treatment. In addition, GH-binding protein was measured at diagnosis. At diagnosis, mean SD scores were: bone ALP, -1.84; PICP -1.77; pyridinoline, -1.42; deoxypyridinoline, -1.66; ICTP, -0.42; P3NP, +1.45; GH, +24.4; IGF-I, -1.70; IGFBP-3, -0.88; IGFBP-2, +2.42; and GH-binding protein, -0.69. Bone ALP, PICP, and IGFBP-3 were all correlated (P < or = 0.03). During induction and intensification, there was shrinkage of the lower leg, with decreases in PICP, pyridinoline, ICTP, and P3NP (P < 0.05), whereas IGF-I and IGFBP-3 increased (P < 0.05). After prednisolone was discontinued, bone ALP and collagen markers increased markedly (P < 0.01), but there was no significant change in IGF-I and IGFBP-3. In 12 children who received high dose i.v. methotrexate, postglucocorticoid increases in bone ALP and PICP were less, whereas those in ICTP and P3NP were greater, compared to levels in children who did not receive methotrexate (P < 0.05). We conclude that ALL itself caused GH resistance and low bone turnover. During early intensive chemotherapy, further suppression of osteoblast proliferation and osteoclast activity occurred, not mediated through the systemic GH axis, probably by the direct action of prednisolone on bone. The postglucocorticoid increase in bone turnover was also independent of the GH axis and was modulated by high dose i.v. methotrexate, which depressed osteoblast recovery and enhanced osteoclast activity.

The systemic stress response to thermal injury in children

OBJECTIVE

Thermal injury is extremely stressful, but data characterizing the endocrine stress response to this injury in children are sparse. The objective of this study was to measure the effects of thermal injury on the levels of stress hormones in children and to assess the temporal changes associated with them.

PATIENTS

Twenty-three children, 13 girls and 10 boys aged between 5 months and 12 years 3 months (mean, 2 years 11 months), with burns covering 10-61% of their body surface (mean, 20.5%) were studied during the first 5 days following injury.

MEASUREMENTS

The levels of arginine vasopressin, angiotensin II, cortisol, adrenaline, noradrenaline and dopamine were measured in sequential blood samples obtained from thermally injured children on admission and at specified time intervals during the 5 days of the investigation.

RESULTS

At admission the concentrations of all the hormones were high, and varied widely between individual patients. The geometric mean and 95% confidence intervals of admission hormone levels were as follows: arginine vasopressin 18.3 (8.3-40.7) pmol/l; angiotensin II 122.0 (56.0-266.2) pmol/l; cortisol 650.6 (473.0-895.0) nmol/l; dopamine 1.0 (0.1-8.0) nmol/l; adrenaline 6.4 (3.2-12.5) nmol/l and noradrenaline 2.3 (1.3-4.3) nmol/l. Although the concentrations of arginine vasopressin and cortisol returned to normal 24 to 36 h after admission, the levels of angiotensin II, adrenaline and dopamine fluctuated and remained higher than normal throughout the study (108 h).

CONCLUSIONS

Thermal injury results in the release of abnormally high levels of stress hormones in children. Although there are similarities between some of the data reported here and those reported in adults, higher levels of adrenaline and lower levels of noradrenaline than reported in adults suggest important differences too. These differences may need to be taken into account in the management of burn-injured children.

A novel oestrogen-regulated gene in human breast cancer cells identified by differential display

Screening by differential display of oestrogen-sensitive MCF7 human breast cancer cells grown in the short-term (6 days) and long-term (70 weeks) absence of oestrogen has led to the identification of a new oestrogen-regulated mRNA. The cDNA isolated by differential display has 100% homology from nucleotides 615 to 859 of the published sequence for the mRNA for human megakaryocyte CD63 antigen but has a 3' tail extended by 23 nucleotides. Northern blotting has confirmed that this mRNA is regulated by oestrogen in both MCF7 and T47D human breast cancer cell lines.

Tocotrienols inhibit the growth of human breast cancer cells irrespective of estrogen receptor status

Potential antiproliferative effects of tocotrienols, the major vitamin E component in palm oil, were investigated on the growth of both estrogen-responsive (ER+) MCF7 human breast cancer cells and estrogen-unresponsive (ER-) MDA-MB-231 human breast cancer cells, and effects were compared with those of alpha-tocopherol (alphaT). The tocotrienol-rich fraction (TRF) of palm oil inhibited growth of MCF7 cells in both the presence and absence of estradiol with a nonlinear dose-response but such that complete suppression of growth was achieved at 8 microg/mL. MDA-MB-231 cells were also inhibited by TRF but with a linear dose-response such that 20 microg/mL TRF was needed for complete growth suppression. Separation of the TRF into individual tocotrienols revealed that all fractions could inhibit growth of both ER+ and ER- cells and of ER+ cells in both the presence and absence of estradiol. However, the gamma- and delta-fractions were the most inhibitory. Complete inhibition of MCF7 cell growth was achieved at 6 microg/mL of gamma-tocotrienol/delta-tocotrienol (gammaT3/deltaT3) in the absence of estradiol and 10 microg/mL of deltaT3 in the presence of estradiol, whereas complete suppression of MDA-MB-231 cell growth was not achieved even at concentrations of 10 microg/mL of deltaT3. By contrast to these inhibitory effects of tocotrienols, alphaT had no inhibitory effect on MCF7 cell growth in either the presence or the absence of estradiol, nor on MDA-MB-231 cell growth. These results confirm studies using other sublines of human breast cancer cells and demonstrate that tocotrienols can exert direct inhibitory effects on the growth of breast cancer cells. In searching for the mechanism of inhibition, studies of the effects of TRF on estrogen-regulated pS2 gene expression in MCF7 cells showed that tocotrienols do not act via an estrogen receptor-mediated pathway and must therefore act differently from estrogen antagonists. Furthermore, tocotrienols did not increase levels of growth-inhibitory insulin-like growth factor binding proteins (IGFBP) in MCF7 cells, implying also a different mechanism from that proposed for retinoic acid inhibition of estrogen-responsive breast cancer cell growth. Inhibition of the growth of breast cancer cells by tocotrienols could have important clinical implications not only because tocotrienols are able to inhibit the growth of both ER+ and ER- phenotypes but also because ER+ cells could be growth-inhibited in the presence as well as in the absence of estradiol. Future clinical applications of TRF could come from potential growth suppression of ER+ breast cancer cells otherwise resistant to growth inhibition by antiestrogens and retinoic acid.

Stimulus transmission in the auditory receptor organs of the foreleg of bushcrickets (Tettigoniidae) I. The role of the tympana

The auditory organs of the tettigoniid are located just below the femoral tibial joint in the forelegs. Structurally each auditory organ consists of a tonotopically organized crista acustica and intermediate organ and associated sound conducting structures; an acoustic trachea and two lateral tympanic membranes located at the level of the receptor complex. The receptor cells and associated satellite structures are located in a channel filled with hemolymph fluid. The vibratory response characteristics of the tympanic membranes generated by sound stimulation over the frequency range 2-40 kHz have been studied using laser vibrometry. The acoustic trachea was found to be the principal structure through which sound energy reached the tympana. The velocity of propagation down the trachea was observed to be independent of the frequency and appreciably lower than the velocity of sound in free space. Structurally the tympana are found to be partially in contact with the air in the trachea and with the hemolymph in the channel containing the receptor cells. The two tympana were found to oscillate in phase, with a broad band frequency response, have linear coherent response characteristics and small time constant. Higher modes of vibration were not observed. Measurements of the pattern of vibration of the tympana showed that these structures vibrate as hinged flaps rather than vibrating stretched membranes. These findings, together with the morphology of the organ and physiological data from the receptor cells, suggest the possibility of an impedance matching function for the tympana in the transmission of acoustic energy to the receptor cells in the tettigoniid ear.

The bigger the burn, the greater the stress

Data characterizing the endocrine stress response to burn injury in children are sparse. We have measured the levels of the stress hormones arginine vasopressin, catecholamines-adrenaline, noradrenaline and dopamine-atrial natriuretic peptide and hormones of the renin-angiotensin-aldosterone system in admission blood samples taken from 35 children admitted to the burns unit of the regional children's hospital. Hormone levels were compared with the size of burn injury. With the exception of adrenaline, there were significant positive correlations between vasopressin (r = 0.707, p < 0.0001), plasma renin activity (r = 0.721, P < 0.0001), angiotensin II (r = 0.512, P = 0.002), aldosterone (r = 0.620, P < 0.0001), noradrenaline (r = 0.430, P = 0.0189), dopamine (r = 0.627, P = 0.0024) and percentage burn surface area, and a negative correlation between atrial natriuretic peptide (r = 0.548, P = 0.0008) and burn surface area. It is concluded that the hormones which react to stress are very sensitive to burn injury in children, and that the magnitude of their response is closely related to the size of the burn surface area.

Sound production in crickets

The calls of male Gryllus bimaculatus were digitally recorded under four different conditions: in air; in 80 % He/20 % O2; with the tympana occluded with wax in air and finally in the helium/oxygen mixture. The principal frequency component, usually referred to as the carrier frequency, was analysed in a large sample of chirps recorded in the four conditions. In all four recording conditions, the principal frequency component was found to vary from chirp to chirp. The mean of the distribution of the principal frequency component was different in the four recording conditions. Insects with occluded tympana produced in air a greater dispersion of the principal frequency component than insects with normal functioning ears. The spectrum of an individual chirp generally contained two frequency components, the principal component, which was related to the plectrum&shy;file strike rate, and a second component, which was related to the free vibration of the wings. The subalar air space volume is shown to act as an acoustic resonator and is important in the filtering and amplification of the sound signal. These observations were confirmed by a model stridulatory system. The model system shows that the resonant frequency of the subalar space is dependent upon the square root of the effective volume of the space. The results suggest that song generation in crickets is a dynamic process involving an auditory feedback control loop. The singing insects appear to be able to control the plectrum&shy;file strike rate as well as the resonant frequency of the subalar space by changing the relative position of the wings and the abdomen, hence varying the volume.

Functional organisation of the metathoracic femoral chordotonal organ in the cricket Acheta domesticus

The metathoracic chordotonal organ of the cricket Acheta domesticus (Gryllidae) consists of two closely associated scoloparia situated proximally within the femur with their distal ends connected by a pair of ligaments to an apodeme arising from the tibia. The smaller scoloparium is associated with the dorsal ligament, which arises from the dorsal surface of the apodeme 150 &micro;m from its proximal end. The larger scoloparium is attached directly to the proximal end of the apodeme by a larger ventral ligament. Both ligaments are composed of bundles of attachment cells containing densely packed microtubules. Longitudinally orientated, Acid-Fuchsin-staining fibrils are found in an extracellular matrix surrounding the individual attachment cells. Similar fibrils occur in the sheath surrounding each ligament. The fibrils are thickest and most densely packed in the sheath surrounding the ventral ligament. They are thinner and more sparsely distributed in the sheath of the dorsal ligament. The finest fibrils are found in the extracellular matrix surrounding individual attachment cells. Staining with phosphotungstic acid provides the first evidence that they are elastic. The ventral ligament also contains a spring-like cuticular core arising as a proximal extension of the apodeme. As femoro-tibial angle changes, the cuticular core changes in length, shortening with tibial extension and lengthening with flexion. Ventral ligament attachment cells terminate at different levels along the cuticular core. This arrangement provides a new possible mechanism for differential sensitivity of the sensory neurones associated with the attachment cells.

Electromotive administration of a new morphine formulation: morphine citrate

Two formulations of morphine citrate were synthesized: trimorphine citrate, 3(MH)+(C6H5O7)3- and morphine sodium citrate, 3(MH)+3Na+2(C6H5O7)3-. Four healthy individuals volunteered to undergo electromotive administration of the two formulations. Application of electric current (2 mA) to solutions of trimorphine citrate for 1 h resulted in iontophoretic transcutaneous administration of therapeutic quantities of morphine, without deleterious reduction in the pH of the drug solutions. Application of a 2-mA current to solutions of morphine sodium citrate for 2 h resulted in combined iontophoretic and electrophoretic delivery of morphine with increased administration rates and an improved buffering capacity of the drug solutions.

Electromotive administration of guanethidine for treatment of reflex sympathetic dystrophy: a pilot study in eight patients

Persistent neuropathic pain is associated with diagnostic and therapeutic challenges that may be very difficult to resolve. This report describes eight patients with incapacitating, posttraumatic neuropathic pain characteristic of reflex sympathetic dystrophy (RSD) who were treated by electromotive administration of guanethidine into affected areas of skin. Following 1-5 treatments, six patients experienced complete resolution of all superficial symptoms of hyperalgesia, pain, pallor, coolness, and sweating of the affected areas. One patient demonstrated partial relief of these symptoms, and one patient failed to respond. The results of this preliminary study suggest that electromotive administration of the the sympatholytic agent, guanethidine, may be useful in the treatment of some types of neuropathic pain. These findings justify the implementation of further controlled studies.

Iontophoresis of drugs in the bladder wall: equipment and preliminary studies

Iontophoresis is the active transport of ions into tissues by means of an electric current: Ji = -D(i)delta Ci/delta chi + DizeECi/kT. Where Ji is the total ionic flux, D(i) the diffusion coefficient, Ci the concentration, z the valency, and E the electric field. The first expression on the right side of the equation is Fick's law of diffusion and approaches zero for bladder mucosa, which leads to uncertain results following intravesical administration of various therapeutic agents. The application of an electric field will potentially accelerate drug administration into the bladder wall in a controllable manner. To evaluate this concept, an appropriate source of electric current and electrodes was fabricated; then, studies were conducted in human cadaveric bladders and clinical trials in human subjects. Ionized dyes were applied in duplicate to 10 fresh cadaveric bladders. Electric currents (3.5-5.0 mA) were applied for 20 min to 10 solutions, and no current was used in 10 controls. Twenty-eight patients had 100 ml solutions of 1% mepivacaine or lidocaine with epinephrine infused into their bladders prior to endoscopic resections. Twenty-two patients received currents of 10-20 mA for 10-20 min, and 6 controls had either no drugs or a current of reverse polarity applied. Visually and on microscopy, the 10 control cadaveric bladder surfaces demonstrated only faint staining of the surface mucosa whereas the experimental surfaces showed full-thickness staining of the mucosa extending into the muscularis. The 6 control patients required supplemental anesthesia or abandonment of the operative procedure. Of the 22 experimental subjects, 16 tolerated procedures with up to 25 g of tissue removed by diathermic resection.

Control of diabetes through a subcutaneous peritoneal access device (SPAD) in patients with resistance to subcutaneously injected insulin

In 2 patients with insulin dependent diabetes and resistance to subcutaneously injected insulin, adequate glucose homeostasis was achieved following the administration of insulin through a subcutaneous peritoneal access device (SPAD). Fasting and post-prandial plasma glucose concentrations fell to near normal levels and HbA1 fell from 17.8% to 9% and from 15.4% to 8% respectively. Insulin requirements fell from 3,000 and 8,000 units to 160 and 100 units per day, respectively. Measurements of sequential free insulin concentrations in serum following subcutaneous and intraperitoneal insulin injection (100 i.u.) showed a significant increase in serum free insulin following intraperitoneal injection, but none after subcutaneous injection. Glucose concentrations fell after intraperitoneal injection of insulin, but not after subcutaneous injection. It is concluded that: intraperitoneal insulin administration is an effective alternative to subcutaneous injections of insulin in patients with this form of insulin resistance; and in patients with this form of insulin resistance, subcutaneous injections of insulin are not followed by an increase in serum free insulin.

Diabetic pregnancy managed with intraperitoneal insulin

A woman with insulin-dependent diabetes (IDDM) and resistance to subcutaneously injected insulin conceived while being treated with intraperitoneal (i.p.) insulin administered through a recently developed subcutaneous peritoneal access device (SPAD). She continued on this regimen during the pregnancy and at 37 weeks was delivered of a normal baby by Caesarian section. During her pregnancy, she had 2 episodes of infection of the SPAD, which were rapidly controlled by local instillation of antibiotics. Her diabetes remained under excellent control (HbA1: 7.3-7.5%) throughout her pregnancy. This case demonstrates that in such patients i.p. administration of insulin through a SPAD is a feasible mode of management during pregnancy.

Intraperitoneal insulin administration produces a positive portal-systemic blood insulin gradient in unanesthetized, unrestrained swine

The present study was performed to evaluate the porto-systemic insulin gradient in response to (1) glucose feeding (2) intramuscular insulin administration, and (3) peritoneal insulin administration in unanesthetized swine. The experiment was designed to verify the hypothesis that intraperitoneal insulin administered might lead to a more physiologic portal vein insulin concentration than systemic administration of a similar insulin dose. Studies were performed in 4 domestic swine with chronic, indwelling catheters in the inferior vena cava and portal vein. Unpaired studied of the absolute portal venous and systemic venous insulin concentrations were performed in response to glucose prn(n = 4), 1 unit regular insulin/kg i.m.(n = 4), and 1 unit regular insulin/kg i.p.(n = 5). Timed blood samples were obtained and serum insulin concentrations determined by RIA. Portal and caval serum insulin concentrations following intramuscular insulin injection showed no significant difference. A significant portal vein insulin excess (p less than 0.001) was demonstrated following both feeding and intraperitoneal insulin.

Controlled ultrafiltration during single-pass dialysis with the RP-6 dialyzer and evaluation of its time-dependent ultrafiltration index

A simple and inexpensive method is described for controlling ultrafiltration when using the high flux RP-6 dialyzer. When th RP-6 is operated in the co-current mode and with single-pass dialysate delivery, (PBo-PDo) can be used to accurately and safely control ultrafiltration. Combined results from ten dialyses indicate there is a pressure-dependent concentration polarization which affects ultra-filtration as reported previously, and in addition, a time-dependent effect indicating a more complex dialyzer/blood interaction. The ultrafiltration index decreases linearly with time. The ultrafiltration can be adequately predicted by (Formula: see text).

Measurement of phenylalanine in routine care of phenylketonuric children

Fluorimetry, paper and column chromatography, and bacterial inhibition assay have been compared in the quantitation of serum or blood phenylalanine at levels ranging from 1 to over 30 mg/100 ml. Special attention was paid to levels of 2 mg or less and to those in excess of 20 mg/100 ml, since these have therapeutic implications. Bacterial inhibition assay, under routine conditions, tended to read low or not at all at 2 mg or less, and to read high above 20 mg/100 ml so that it `failed safe' under such conditions. Paper chromatography was shown to be a simple, rapid, and economic method of getting accurate results at all levels in the range examined.