γδ T cells respond directly and selectively to the skin commensal yeast Malassezia for IL-17-dependent fungal control

Stable microbial colonization of the skin depends on tight control by the host immune system. The lipid-dependent yeast Malassezia typically colonizes skin as a harmless commensal and is subject to host type 17 immunosurveillance, but this fungus has also been associated with diverse skin pathologies in both humans and animals. Using a murine model of Malassezia exposure, we show that Vγ4+ dermal γδ T cells expand rapidly and are the major source of IL-17A mediating fungal control in colonized skin. A pool of memory-like Malassezia-responsive Vγ4+ T cells persisted in the skin, were enriched in draining lymph nodes even after fungal clearance, and were protective upon fungal re-exposure up to several weeks later. Induction of γδT17 immunity depended on IL-23 and IL-1 family cytokine signalling, whereas Toll-like and C-type lectin receptors were dispensable. Furthermore, Vγ4+ T cells from Malassezia-exposed hosts were able to respond directly and selectively to Malassezia-derived ligands, independently of antigen-presenting host cells. The fungal moieties detected were shared across diverse species of the Malassezia genus, but not conserved in other Basidiomycota or Ascomycota. These data provide novel mechanistic insight into the induction and maintenance of type 17 immunosurveillance of skin commensal colonization that has significant implications for cutaneous health.

Mucosal Immunity to Gut Fungi in Health and Inflammatory Bowel Disease

The gut microbiome is a diverse microbial community composed of bacteria, viruses, and fungi that plays a major role in human health and disease. Dysregulation of these gut organisms in a genetically susceptible host is fundamental to the pathogenesis of inflammatory bowel disease (IBD). While bacterial dysbiosis has been a predominant focus of research for many years, there is growing recognition that fungal interactions with the host immune system are an important driver of gut inflammation. Candida albicans is likely the most studied fungus in the context of IBD, being a near universal gut commensal in humans and also a major barrier-invasive pathogen. There is emerging evidence that intra-strain variation in C. albicans virulence factors exerts a critical influence on IBD pathophysiology. In this review, we describe the immunological impacts of variations in C. lbicans colonisation, morphology, genetics, and proteomics in IBD, as well as the clinical and therapeutic implications.

Development, Management and Utilization of a Kiwifruit (Actinidia spp.) In Vitro Collection: A New Zealand Perspective

The New Zealand Institute for Plant and Food Research Limited (PFR) supports a large kiwifruit breeding program that includes more than twenty Actinidia species. Almost all the kiwifruit accessions are held as field collections across a range of locations, though not all plants are at multiple locations. An in vitro collection of kiwifruit in New Zealand was established upon the arrival of Pseudomonas syringae pv. Actinadiae-biovar 3 in 2010. The value of an in vitro collection has been emphasized by restrictions on importation of new plants into New Zealand and increasing awareness of the array of biotic and abiotic threats to field collections. The PFR in vitro collection currently holds about 450 genotypes from various species, mostly A. chinensis var. chinensis and A. chinensis var. deliciosa. These collections and the in vitro facilities are used for germplasm conservation, identification of disease-free plants, reference collections and making plants available to users. Management of such a diverse collection requires appropriate protocols, excellent documentation, training, sample tracking and databasing and true-to-type testing, as well as specialized facilities and resources. This review also discusses the New Zealand biosecurity and compliance regime governing kiwifruit plant movement, and how protocols employed by the facility aid the movement of pathogen-free plants within and from New Zealand.

Eradication of Potato Virus S, Potato Virus A, and Potato Virus M From Infected in vitro-Grown Potato Shoots Using in vitro Therapies

Certain viruses dramatically affect yield and quality of potatoes and have proved difficult to eradicate with current approaches. Here, we describe a reliable and efficient virus eradication method that is high throughput and more efficacious at producing virus-free potato plants than current reported methods. Thermotherapy, chemotherapy, and cryotherapy treatments were tested alone and in combination for ability to eradicate single and mixed Potato virus S (PVS), Potato virus A (PVA), and Potato virus M (PVM) infections from three potato cultivars. Chemotherapy treatments were undertaken on in vitro shoot segments for four weeks in culture medium supplemented with 100 mg L^-1 ribavirin. Thermotherapy on in vitro shoot segments was applied for two weeks at 40°C (day) and 28°C (night) with a 16 h photoperiod. Plant vitrification solution 2 (PVS2) and cryotherapy treatments included a shoot tip preculture followed by exposure to PVS2 either without or with liquid nitrogen (LN, cryotherapy) treatment. The virus status of control and recovered plants following therapies was assessed in post-regeneration culture after 3 months and then retested in plants after they had been growing in a greenhouse for a further 3 months. Microtuber production was investigated using in vitro virus-free and virus-infected segments. We found that thermotherapy and cryotherapy (60 min PVS2 + LN) used alone were not effective in virus eradication, while chemotherapy was better but with variable efficacy (20-100%). The most effective result (70-100% virus eradication) was obtained by combining chemotherapy with cryotherapy, or by consecutive chemotherapy, combined chemotherapy and thermotherapy, then cryotherapy treatments irrespective of cultivar. Regrowth following the two best virus eradication treatments was similar ranging from 8.6 to 29% across the three cultivars. The importance of virus removal on yield was reflected in "Dunluce" free of PVS having higher numbers of microtubers and in "V500' free of PVS and PVA having a greater proportion of microtubers > 5 mm. Our improved procedure has potential for producing virus-free planting material for the potato industry. It could also underpin the global exchange of virus-free germplasm for conservation and breeding programs.

AB0573 DUPILUMAB-INDUCED ENTHESITIS/ARTHRITIS IN PATIENTS WITH ATOPIC DERMATITIS: A RETROSPECTIVE OBSERVATIONAL STUDY

Background:

Atopic dermatitis (AD) is a common skin condition with a prevalence of 2–10% in adults1. IL-4 and IL-13 play a key role in the pathogenesis. Dupilumab, a human IgG4 monoclonal antibody binding the alpha subunit of the IL-4 receptor, blocking IL-4 and IL-13 signaling, has important efficacy in this difficult to treat disease. We first reported a musculoskeletal (MSK) adverse effect of enthesis/arthritis developing in 3 patients in 20192.

Objectives:

To report the ongoing experience at our centre of this new clinical paradigm, incidence and patient progress including clinical presentation, imaging and management.

Methods:

Clinical and radiological data was collected from electronic case records of all cases presenting with features of enthesitis/arthritis between October 2018 and January 2021.

Results:

Since initiation of dupilumab at GSTT, approximately 400 adults with moderate-to-severe AD have received at least one dose. Of these, 23 patients (14 men, 9 women) had the clinical syndrome of inflammatory enthesitis/tenosynovitis/arthritis. Nine patients had both enthesitis and arthritis, 10 enthesitis, 3 enthesitis and tenosynovitis and 1 arthritis only. Four of these also reported new onset inflammatory back pain symptoms. None had a preceding history of arthritis or enthesitis. Median onset of symptoms following initiation of dupilumab was 4 months. However, onset of symptoms ranged between 2 weeks and 48 months. Imaging (US/MRI) was performed in 18 patients, 11 with Doppler US positive enthesitis confirming clinical findings. Most common sites were lateral epicondyles, achilles and patella tendons. Two patients with more disabling symptoms had MRI confirmed gluteus medius and hamstring enthesitis and arthritis. Spine and SI joint MRI in 4 patients was negative. Most patients had normal inflammatory markers except 2; CRP 117, ESR 96 and CRP 13, ESR 10. All patients had very good AD response to dupilumab, average EASI score before and after Dupilumab was 21 and 4.2 respectively. One patient developed skin manifestations of guttate psoriasis, with subsequent disabling arthritis/enthesitis. Due to the life-changing beneficial effect of dupilumab therapy most patients did not want to stop therapy. We used NSAID therapy, etoricoxib/celecoxib/naproxen for symptom relief which was usually partly effective allowing continuation of dupilumab treatment in most. Five patients with severe MSK symptoms stopped Dupilumab completely. Some patients temporarily paused therapy but re-started as their AD became worse, often changing from the usual 2 weekly to 4 weekly dosing. Most patients continuing dupilumab had persistent MSK symptoms. Four patients who stopped dupilumab were treated with baricitinib, which has potential efficacy for both MSK symptoms and AD. Two did not tolerate it and remained on NSAID therapy.

Conclusion:

These data further characterize a new syndrome of enthesitis and/or arthritis induced by Dupilumab. In those with mild MSK symptoms use of NSAIDs allows continuation of full-dose dupilumab, in moderate cases reducing dupilumab dose frequency plus NSAID therapy maintains function. Most patients had on-going MSK symptoms. In more severe cases JAKi therapy may be an effective strategy. Our initial hypothesis that inhibition of IL-4/13 by dupilumab triggers an IL-17/23/TNF-mediated inflammatory MSK syndrome in some patients is supported by a recent in vitro study3.

References:

[1]Beck L et al. Dupilumab Treatment in Adults with Moderate-to-Severe Atopic Dermatitis. July 10, 2014. N Engl J Med 2014; 371:130-139

[2]Willsmore ZN et al. Development of inflammatory arthritis and enthesitis in patients on dupilumab: a case series. Br J Dermatol 2019; 0. doi:10.1111/bjd.18031.

[3]Bridegwood C et al. Regulation of entheseal IL-23 expression by IL-4 and IL-13 as an explanation for arthropathy development under dupilumab therapy. Rheumatology (Oxford). 2020 Nov 30:keaa568. doi: 10.1093/rheumatology/keaa568

Disclosure of Interests:

Joseph Nathan: None declared., Catherine Hughes Speakers bureau: Presented for Abbvie, Samir Patel: None declared., Libin Mathew: None declared., Catherine Smith Grant/research support from: Grants/research support; Professor Smith is a PI/CoPI on a number of commercially supported studie (Abbvie, Janssen, Leo, Sanofi)., Andrew Pink Paid instructor for: Speaker or advisor to Lilly, Abbvie, Sanofi, Leo, Almirall, Novartis, Janssen, UCB, Galderma, BMS, La-Roche Posay, Richard Woolf: None declared., Bina Menon Speakers bureau: Presented for Abbvie, L Bruce Kirkham Grant/research support from: Professor Kirkham has received honoraria and/or research funding from AbbVie, Eli Lilly, Gilead, Janssen, Novartis, Pfizer and UCB.

Cold, antioxidant and osmotic pre-treatments maintain the structural integrity of meristematic cells and improve plant regeneration in cryopreserved kiwifruit shoot tips

Cryopreservation is a reliable and cost-effective method for the long-term preservation of clonally propagated species. The number of vegetatively propagated species conserved by cryopreservation is increasing through development of vitrification-based methods; droplet vitrification in particular is becoming the preferred method for many species, as it ensures fast freezing and thawing rates. This research investigated if cold, antioxidant and osmotic pre-treatments could maintain the structural integrity of cells, thence aid in developing a droplet vitrification protocol for kiwifruit using Actinidia chinensis var. chinensis 'Hort16A' as a model. Cold acclimation of donor plantlets at 4 °C for 2 weeks followed by sucrose pre-culture of shoot tips and supplementation of ascorbic acid (0.4 mM) in all media throughout the procedure registered 40% regeneration after cryopreservation. Transmission electron microscope imaging of meristematic cells confirmed sucrose and ascorbic acid pre-treatment of shoot tips from cold acclimated plantlets following treatment in vitrification solution exhibited severe plasmolysis and some disruption of membrane and vacuoles. In contrast cells without cold acclimation or sucrose and ascorbic acid pre-treatments exhibited minimal change after exposure to vitrification solution. After cryopreservation and recovery, all cells of untreated shoot tips showed rupture of the plasma membrane, loss of cytoplasmic contents and organelle distortions. By comparison, most pre-treated shoot-tip cells from cold acclimated plantlets retained their structural integrity, showing that only those cells that have been dehydrated and plasmolysed can withstand cryopreservation by vitrification.

Sci-Thur AM: Planning - 06: Planning target volume margin suitability in lung stereotactic body radiation therapy: A preliminary evaluation using cone-beam computed tomography

Stereotactic body radiation therapy (SBRT) requires precise delivery of radiation to the target; intra- and inter-fraction lung tumour motion may adversely impact local tumour control. The purpose of this study was to retrospectively evaluate the impact of planning target volume (PTV) margin size on the coverage of the internal target volume (ITV) as localized in pre- and post-treatment cone-beam computed tomography (CBCT) images. Data from two patients undergoing SBRT were evaluated. For planning, free-breathing and 4DCT scans were performed, and used to contour the ITV. A 5mm margin was added to create the PTV. During treatment, 14 CBCTs were collected pre- and post-beam delivery. A data set comprising the average 4DCT intensities where available and treatment planning CT intensities for voxels that were beyond the field of view of the 4DCT was constructed. Registration of the combined planning image to each CBCT was performed using a deformable image registration algorithm. The transformations aligning the combined planning image with the CBCTs were applied to the planning ITV to obtain the treatment ITVs. For each CBCT, the fraction of treatment ITV within the PTV was determined using Boolean logic. This was repeated for various PTV margins ranging from 0 to 10 mm at 1mm intervals. The 3 and 5 mm PTV margins covered 95.1 ± 5.9% and 99.0 ± 2.0% of the ITV, respectively. Analysis of additional patients will be performed to confirm these preliminary results, which reinforce the use of a 5mm PTV margin for lung SBRT.

Pulmonary Scopulariopsis in a chronic tobacco smoker

A 70-year-old male smoker, with a three-month status of post-balloon angioplasty for ischaemic heart disease, presented with a one-week history of fever, haemoptysis and chest discomfort on coughing. The patient did not report any loss of weight or appetite. On examination, he was febrile. Pulmonary function tests revealed obstructive airway disease. High resolution computed tomography of the lungs revealed fibrosis with bronchiectasis in both the upper lobes, and a spiculating subpleural mass in the posterior aspect of the right lung apex. Subsequent bronchoalveolar lavage (BAL) culture yielded the Scopulariopsis species. Our patient was treated with a four-week course of amphotericin B, followed by itraconazole. At the 24-month follow-up, the patient was asymptomatic. Subsequent BAL cultures revealed no fungal growths, and radiological studies showed a regression in the lesion.

Effects of Design Parameters on the Sensitivity of a Micro-Cantilever Based Biosensor

Piezo-resistive actuation of a microcantilever induced by biomolecular binding such as DNA hybridization and antibody-antigen binding is an important principle useful in biosensing applications. As the magnitude of the forces exerted is small, increasing the sensitivity of the microcantilever becomes critical. In this paper, we are considering to achieve this by geometric variation of the cantilever. The sensitivity of the cantilever was improved so that the device can sense the presence of antigen even if the magnitude of surface-stresses over the microcantilever was very small. We consider a `T-shaped' cantilver that eliminates the disadvantages while improving the sensitivity simultaneously. Simulations for validation have been performed using Intellisuite software (a MEMS design and simulation package). The simulations reveal that the T-shaped microcantilver is almost as sensitive as a thin cantilever and has relatively very low buckling effect. Simulations also reveal that with an increase in thickness of the cantilever, there is a proportional decrease in the sensitivity. This paper presents an analytical modeling and simulation studies of a piezoresistive cantilever used as MEMS based biosensor for the detection of cardiac markers. Diagnosis of Myocardial Infarction was achieved by the nanomechanical deflection of the microcantilever due to adsorption of the Troponin I complex. The deflection of the microcantilever was measured in terms of the piezoresistive changes by implanting boron at the anchor point where there is maximum strain due to the adsorption of the analyte molecules. The biochemical interactions between the Cardiac Troponin I (cTnl) complex and the immobilized antibodies would cause change in resistance of the piezoresistor integrated at the anchor point. A ‘T’ shaped microcantilever design was proposed for the study. The distal end of the device was coated with gold. The sensitivity of the cantilever was improved so that the device can sense the presence of antigen even if the magnitude of surface-stresses over the microcantilever was very small. To obtain an application specific optimum design parameter and predict the cantilever performance. The miniaturization of the cantilever-based biosensor leads to significant advantages in the absolute device sensitivity.

Retrospective analysis of 58 children with retinoblastoma”

We performed a retrospective analysis of 58 children with retinoblastoma seen at the University of Illinois at Chicago between 1960 and 1982. Our findings showed an almost equal distribution by sex, a predominance (69%) of white patients, and a common presenting symptom (70%) of leukocoria, with (22%) or without (48%) strabismus. Unilateral involvement was noted in 35 patients (60%). Of the 23 (40%) bilaterally affected children, 19 had simultaneous involvement at the time of diagnosis. All bilateral and 90% of the unilateral cases were diagnosed before age five years. Family history was positive for retinoblastoma in five bilateral and one unilateral case. At the time of diagnosis, 35 patients had stage V disease (Reese-Ellsworth classification, Table 1). Depending on the stage of disease treatment included enucleation, radiation, and chemotherapy. Mortality was 25% from 1960 to 1974, and zero thereafter.

3D CAD Based Conceptual Design of a Novel Aortic Valve Stent

Vascular support structures are an important tool for treating valve stenosis. A large population of patients are treated for valvular disease and the principal mode of treatment is the use of percutaneous valvuloplasty. Stent devices are proving to be an improved treatment method; these devices now account for 20% of treatments in Europe. This new technology provides highly effective results at minimal cost and short duration of hospitalization. Accurate and reliable structural analysis provides essential information to the design team in an environment where in vivio experimentation is extremely expensive, or impossible. This paper describe the design of vascular support structure (stents), to provide designers with estimates of the critical parameters which are essential to restore the functions of the endothelium of the Aorta during and after implantation without injuring it. Stent geometries were uniquely defined using the following parameters. (a) Diameter of the aorta; (b) Distance between the aortic root and the coronary artery roots; (c) Position of the coronary arteries; (d) Diameter of the coronaries; (e) Stent–Endothelium Mechanics. Keeping these parameters into consideration a novel stent model was designed to suit its requirement for percutaneous replacement. The 3D geometry of the repeatable units of the stent was generated using SOLIDWORKS modeling software. Using the repeating unit geometry of each stent design, solid models were generated. The unit consisted of 8 lips with two non crossing struts making a circular diameter of 16 mm at the center and 18 mm at either ends. The upper and the lower portions of the prosthesis has a high radial force, the upper portion flared to fix the stent firmly in the ascending aorta and the lower portion to expand against the calcified leaflets and to avoid recoil. The middle portion which bears the valve is constrained and narrower to avoid obstruction of the coronary arteries. This varying diameter of different parts of the stent creates the blunt hooks at either end of the stent. The methodology described in this paper is proposed as a method to compare and analyze the existing stents and the ones proposed here. However, further analysis and studies are needed before these stents are fabricated and deployed. Animal experiments are being planned currently for this purpose.

3D CAD conceptual design of an artificial knee

Total knee arthroplasty is the end-stage surgical procedure for pain relief in degenerative diseases such as arthritis. There are many models, which were designed so far in five to six decades of arthroplasty history. This research is aimed to design an artificial high-flexion knee, which emphasizes the high-flexion extension range of over 125 deg that would provide the comfort of squatting even after total knee replacement.

Treatment of vasculitic peripheral neuropathy: a retrospective analysis of outcome

BACKGROUND

Vasculitis of the peripheral nervous system (PNS) is rare. There are no controlled treatment trials, and clinical practice is guided by experience from case series and indirectly by analogy with systemic vasculitis.

METHODS

We identified patients (n=212) with possible vasculitic peripheral neuropathy (VPN) from the neuropathology and neurophysiology records of two centres over 28 years. Case-notes were available for 181, from which, 106 cases of clinicopathological VPN were identified. Adequate treatment data were available in 100; follow-up data, in 93.

RESULTS

Of 106 cases, 95 had systemic vasculitis and 11 had vasculitis confined to the PNS. Pharmacological treatment (94/100 cases) was corticosteroid-based, and included cyclophosphamide in 54; 17 received additional agents. Initial stabilization was achieved in all but six. One-year survival was 90.3%. Of the nine who died in the first years (mean age 73 years), seven had received cyclophosphamide, and all but two had severe, multisystem vasculitis. The neurological relapse rate was 10%. Only one relapse occurred after cyclophosphamide treatment. Outcome was reported as good in 72% (78% in those who relapsed).

DISCUSSION

Death and relapse were infrequent in treated patients. Relapse occurred almost exclusively in patients treated with prednisolone alone. Aggressive early treatment with cyclophosphamide may prevent relapse. The current management approach to VPN appears largely effective, especially if cyclophosphamide is used.

Dermatoglyphic peculiarities in children with oral clefts

In humans, the development of the primary palate and the lip is completed by the 7th week of intra uterine life and that of secondary palate by 12th week. The dermal ridges develop in relation to the volar pads, which are formed by the 6th week of gestation and reach maximum size between 12th and 13th weeks. This means that the genetic message contained in the genome--normal or abnormal is deciphered during this period and is also reflected by dermatoglyphics. Hence this study was done in order to observe the differences in dermatoglyphic patterns between the children with oral clefts and normal children and to determine the usefulness of dermatoglyphics in studying the genetic etiology of oral clefts. Dermatoglyphic data from 50 oral cleft children and 50 normal children were collected using the ink method and comparison was done between them. In the present study, we found an increase in the ulnar loop patterns on the distal phalanges of the ten fingers, an increase in the atd angle and an increase in the fluctuating asymmetry of the atd angle in the oral cleft children which indicates the degree of developmental instability of the oral cleft individual.

An in vitro approach to study chromosomal DNA damage

In this study a simple electrophoresis approach has been proposed for assessing DNA damage per chromosome in vitro. Novel procedures of gel casting, sample loading, electrophoresis and quantification of damage have been suggested. Sets of Saccharomyces cerevisiae chromosomes subjected to DNA damage by Bleomycin, Co60-gamma-radiation alone and in combination with Hoechst were studied in detail. Statistical analyses showed that damage induced by Bleomycin bore linear positive correlation with %GA (r = 0.97) and %GT (r = 0.61) contents of chromosomes. Samples pre-treated with Hoechst showed much less damage by Co60-gamma-irradiation as compared to samples not treated with Hoechst but exposed to Co60-gamma-irradiation. The 'protective effect of Hoechst' bore linear positive correlation (r = 0.8) with %TAT content of chromosomes.

Measurements of sulfur dioxide and formaldehyde in Taipei using a differential optical absorption spectrometer

Taipei, the capital city of Taiwan, lies in a basin, and its topography prevents the dispersion of pollutants in the city. As a continuation of our air quality study, from February 1999 through June 1999, we measured the concentrations of SO2 at six different locations and of formaldehyde at five locations using a differential optical absorption spectrometer (DOAS). The average concentration of SO2 varied from 3.5 to 6.6 ppb. The average concentration was highest at Toucheng because of its proximity to point sources. The level in Hsientien was close to that in Toucheng, with Hsinyu showing the lowest concentrations. The DOAS and the Taiwan Air Quality Monitoring Network (TAQMN) measurements for SO2 were highly correlated (r2 > 0.9) for Toucheng, Panchiao, and Hsientien. However, DOAS SO2 concentrations were 2 times higher for Hsientien and slightly lower for Panchiao than the TAQMN concentrations were. The average concentration of formaldehyde varied from 7 to 10 ppb. Diurnal variation of formaldehyde closely followed the variation of ozone, especially when the 1-hr peak ozone concentration was > 60 ppb. Photochemical formation accounted for the ambient levels of formaldehyde in Taipei. Concentration of formaldehyde became significant on days when O3 concentration was high. Our results indicate that DOAS can replace conventional measurement techniques.

Decreased activity of the L-arginine-nitric oxide metabolic pathway in patients with congestive heart failure

BACKGROUND

Impaired endothelium-dependent, nitric oxide (NO)-mediated vasodilation may contribute to increased vasomotor tone in patients with heart failure. Whether decreased endothelium-dependent, NO-mediated vasodilation in patients with heart failure is due to decreased synthesis or increased degradation of NO is unknown.

METHODS AND RESULTS

To specifically assess the synthetic activity of the L-arginine-NO metabolic pathway, urinary excretion of [15N]nitrates and [15N]urea was determined after a primed continuous intravenous infusion of L-[15N]arginine (40 micromol/kg) in 16 patients with congestive heart failure and 9 age-matched normal control subjects at rest and during submaximal treadmill exercise. After infusion of L-[15N]arginine, 24-hour urinary excretion of [15N]nitrates was decreased in patients with congestive heart failure at rest (2.2+/-0.5 versus 8.0+/-2.3 micromol/24 h) and during submaximal exercise (2.4+/-1.2 versus 11. 4+/-4.0 micromol/24 h) compared with control subjects (both P<0.01). After infusion of L-[15N]arginine, 24-hour urinary excretions of [15N]urea at rest in patients with congestive heart failure and control subjects were not different (1.1+/-0.3 versus 1.2+/-0.2 mmol/24 h, P>0.20).

CONCLUSIONS

A specific decrease in synthetic activity of the L-arginine-NO metabolic pathway contributes to decreased endothelium-dependent vasodilation in patients with congestive heart failure.

Cardiovascular responses to application of lower body negative pressure of male volunteers in seated position

Lower body negative pressure (LBNP) has been used to evaluate orthostatic tolerance and for studying the effects of +Gz induced physiological strain and hence has great practical significance in aerospace medicine. Cardiovascular responses in man on application to LBNP (-40 mmHg) in seated (upright) position in a specially designed LBNP chamber have been studied in eight normal healthy male volunteers between the age group of 25-36 yrs. They were subjected to -40 mmHg negative pressure in steps of -10 mmHg for a duration of 5 min each. The total duration of the experiment was 20 min. Heart rate (HR), blood pressure (BP) Cardiac output (CO) were measured and mean blood pressure (MBP) and total peripheral resistance (TPR) were computed. The results indicate a significant increase in HR (P < 0.01), SV (P < 0.01). Studies on limited number of subjects on application to LBNP (40 mmHg) in supine position have also been carried out and compared with the physiological strain induced in subjects in seated position. Study of HR, SV, CO, responses of the subjects on exposure to LBNP in seated position elicit similar response in subjects exposed to +Gz stress as reported by other workers. It is concluded that LBNP technique can be used to study the effects of +Gz induced physiological strain in man.

Calcium sensitising agents in heart failure

Congestive heart failure (CHF) is a common cardiovascular disorder that is characterised, in part, by a decreased cardiac output reserve. Accordingly, there is ongoing interest in the role of positive inotropic agents (e.g. adrenergic agonists and phosphodiesterase type III inhibitors, which mediate their cardiovascular effects via a cyclic adenosine monophosphate-dependent mechanism) in the treatment of CHF. However, enthusiasm for positive inotropic therapy in CHF has been dampened by the results of clinical trials, which have shown that these drugs are associated with an increased risk of mortality. Calcium sensitising agents are a heterogeneous group of positive inotropic agents that mediate their cardiovascular actions (at least in part) by increasing the sensitivity of the contractile elements to calcium. Increased sensitivity to calcium may be related to changes in calcium binding to troponin C, or to direct effects on the actin-myosin complex. In addition, the inhibition of phosphodiesterase type III may contribute to the positive inotropic action of calcium sensitising agents. Five agents with calcium sensitising properties (pimobendan, levosimendan, MCI-154, EMD-53998 and CGP-48506) have been studied as possible therapies for CHF. All of these agents have demonstrated a positive inotropic action in isolated cardiac tissue and in animal models of CHF. In clinical trials, pimobendan, the most extensively studied of these drugs, was well tolerated and was associated with improved exercise tolerance during the first 6 months of therapy; however, it was also associated with a nonsignificant trend towards increased mortality. Because many of the calcium sensitising agents also inhibit phosphodiesterase type III activity, the long term safety of these agents is uncertain. Large-scale survival trials are required to determine the long term safety and efficacy of these agents before their role in the treatment of CHF can be defined.

Effect of amine activators on the properties of chemical cured dental composites

The purpose of this study was to evaluate the reactivity and the effect of concentration of three tertiary amines upon the mechanical properties of a chemical curing dental composite. Chemical cured composite pastes were prepared by keeping peroxide concentration constant at 1 wt% (by weight of resin mixture) and by varying the amine/peroxide molar ratio from 0.25 to 1.5. Composite samples were prepared for all three amine pastes aged for 1, 15, 30, 45, and 60 d stored at 8, 22, and 37 degrees C. The loss in activity of the tertiary amine with time was measured. Changes in compressive strength, diametral tensile strength, and microhardness were also measured. A sharp decrease in working and setting times corresponding to increased activity was noticed with an increased amine content. The activity was found to vary in the order N,N-dimethyl p-toluidine (DMPT) > 2-(4-dimethylaminophenyl)ethanol (DMAPEA) > N,Ndiethanol p-toluidine (DEPT). DMPT is found to be more temperature sensitive than DMAPEA and DEPT. However, DEPT is found to provide better storage stability out of all three amines tested. Each amine was found to possess optimum concentrations at which the mechanical properties showed maximum values. DEPT is preferred for long-term storage stability in chemical-cured dental composites where aging tends to reduce the activity of the amine.

Survey of the practice of electroconvulsive therapy in North Carolina

A survey of North Carolina hospitals was conducted to determine the distribution and characteristics of facilities that offer electroconvulsive therapy (ECT). Parameters examined in the survey included bed size, geographic location, and average volume of ECT treatments. Facilities that offer ECT make up only 14% of total hospitals surveyed. The majority of hospitals with ECT services are located in moderate to large urban areas. Specific areas of practice were surveyed for each facility, including type of ECT device, location of treatments/recovery, methods for monitoring ictal motor seizure, time required to perform treatments, staffing, and potential areas of ECT nursing education. Standard practices at facilities were found to be generally in compliance with American Psychiatric Association recommendations; differences in practices were identified. Potential nursing education topics related to ECT were ranked to determine those most useful to individual nursing staffs.

State of the art: nursing knowledge and electroconvulsive therapy

Nursing services attempting to develop standards for their own facilities will find limited literature specific to nursing and electroconvulsive therapy (ECT) in American publications. From 1966 to December 1994, there were only 19 publications in American nursing journals that provide a specific focus on nursing and ECT. Only one of these articles reported research findings. Twenty-seven citations in Convulsive Therapy included nurse contributors. While the APA Task Force on the Practice of ECT has addressed educational needs of nursing and technical elements of the procedure, there do not currently exist specific standards for nursing practice in ECT. Concerns salient to nursing that have generated articles by nurses include instruction of patients, support to patients and families, safety of patients, assessment of clinical status, informed consent, and nurses' and patients' attitudes about ECT. Nurses are encouraged to join their physician-colleagues in developing and disseminating the information needed for the field of nursing to contribute its own expertise to the care of patients receiving ECT.

Destructive skeletal lesions as the primary initial manifestation of acute childhood leukemia

Bony involvement in leukemia has been long recognized in the medical literature. However, severe osseous changes, as the sole initial manifestation of childhood leukemia is a unique feature of the case reported here.

Seroepidemiology of rubella in Bahrain

Although the Ministry of Health of the State of Bahrain has set priorities for vaccination against a number of communicable diseases including the six target diseases of the Expanded Program of Immunization, no such policy for rubella immunization exists. The incidence of rubella in Bahrain is not precisely known nor is the magnitude of the problem of Congenital Rubella Syndrome. A survey of schoolchildren and primigravidae attending antenatal clinics was undertaken in Bahrain to determine the level of natural immunity against rubella in these groups, which we hope would help us in formulating a vaccination policy. We have found that 67.8% of the 6-7 year old children are susceptible to rubella and that by the age of 18 years susceptibility drops to 10.4%. The decrease in susceptibility was significant until the age of 14 years after which the change became minimal. Efforts should ideally be focused on immunizing all susceptible females before they get married. However, at present, it would be more economical to vaccinate all girls premaritally than to screen and vaccinate those susceptible. When a cheaper screening test for assessing immunity against rubella becomes available, a policy of premarital and post-partum screening followed by vaccination of susceptibles should be put into practice.

Pulmonary function of Indian athletes and sportsmen: comparison with American athletes

Studies were conducted to evaluate pulmonary functions in Indian athletes and sportsmen associated with different athletic events and games. It was found that swimmers were having significantly higher vital capacity (VC) and forced expiratory volume (FEV1) values than all other athletic groups studied. Results have been discussed keeping in view the physiological, functional and structural demands in various events. Pulmonary function values of Indian athletes have also been compared with American athletes of standardized height for a better appraisal of athletic potentiality in our athletes. The importance of athletic training from childhood have been ascribed to be the reason for superior lung volumes and capacities in US athletes.