Sensitive detection and quantification of SARS-CoV-2 in saliva

Saliva has significant advantages as a test medium for detection of SARS-CoV-2 infection in patients, such as ease of collection, minimal requirement of supplies and trained personnel, and safety. Comprehensive validation in a large cohort of prospectively collected specimens with unknown SARS-CoV-2 status should be performed to evaluate the potential and limitations of saliva-based testing. We developed a saliva-based testing pipeline for detection of SARS-CoV-2 nucleic acids using real-time reverse transcription PCR (RT-PCR) and droplet digital PCR (ddPCR) readouts, and measured samples from 137 outpatients tested at a curbside testing facility and 29 inpatients hospitalized for COVID-19. These measurements were compared to the nasal swab results for each patient performed by a certified microbiology laboratory. We found that our saliva testing positively detects 100% (RT-PCR) and 93.75% (ddPCR) of curbside patients that were identified as SARS-CoV-2 positive by the Emergency Use Authorization (EUA) certified nasal swab testing assay. Quantification of viral loads by ddPCR revealed an extremely wide range, with 1 million-fold difference between individual patients. Our results demonstrate for both community screening and hospital settings that saliva testing reliability is on par with that of the nasal swabs in detecting infected cases, and has potential for higher sensitivity when combined with ddPCR in detecting low-abundance viral loads that evade traditional testing methods.

Sensitive detection and quantification of SARS-CoV-2 in saliva

Saliva has significant advantages as a test medium for detection of SARS-CoV-2 infection in patients, such as ease of collection, minimal requirement of supplies and trained personnel, and safety. Comprehensive validation in a large cohort of prospectively collected specimens with unknown SARS-CoV-2 status should be performed to evaluate the potential and limitations of saliva-based testing. We developed a saliva-based testing pipeline for detection of SARS-CoV-2 nucleic acids using real-time reverse transcription PCR (RT-PCR) and droplet digital PCR (ddPCR) readouts, and measured samples from 137 outpatients tested at a curbside testing facility and 29 inpatients hospitalized for COVID-19. These measurements were compared to the nasal swab results for each patient performed by a certified microbiology laboratory. We found that our saliva testing positively detects 100% (RT-PCR) and 93.75% (ddPCR) of curbside patients that were identified as SARS-CoV-2 positive by the Emergency Use Authorization (EUA) certified nasal swab testing assay. Quantification of viral loads by ddPCR revealed an extremely wide range, with 1 million-fold difference between individual patients. Our results demonstrate for both community screening and hospital settings that saliva testing reliability is on par with that of the nasal swabs in detecting infected cases, and has potential for higher sensitivity when combined with ddPCR in detecting low-abundance viral loads that evade traditional testing methods.

Meta-analyses of randomized controlled trials reporting the effect of home foot temperature monitoring, patient education or offloading footwear on the incidence of diabetes-related foot ulcers

AIM

The aim of this study was to perform an up-to-date systematic review and meta-analysis of randomized controlled trials (RCTs) examining the efficacy of home foot temperature monitoring, patient education and offloading footwear in reducing the incidence of diabetes-related foot ulcers.

METHODS

A literature search was performed using MEDLINE, PubMed, CINAHL, Scopus and Cochrane databases to identify relevant original studies. Meta-analyses were performed using intention-to-treat principals for worst (main analysis) and best (sub-analysis) case scenarios. Leave-one-out sensitivity analyses were used to assess the consistency of findings.

RESULTS

Of 7575 unique records, 17 RCTs involving 2729 participants were included. Four tested home foot temperature monitoring (n = 468), six examined patient education (n = 823) and seven assessed offloading footwear (n = 1438). Participants' who performed home foot temperature monitoring [odds ratio (OR) 0.51, 95% confidence interval (CI) 0.31 to 0.84; n = 468] and those provided offloading footwear (OR 0.48, 95% CI 0.29 to 0.80; n = 1438) were less likely to develop a diabetes-related foot ulcer. Patient education programmes did not significantly reduce diabetes-related foot ulcer incidence (OR 0.59, 95% CI 0.29 to 1.20; n = 823). Sensitivity analyses suggested that offloading footwear findings were consistent, but home foot temperature findings were dependent on the individual inclusion of one trial. All RCTs had either high or unclear risk of bias.

CONCLUSION

This meta-analysis suggests that offloading footwear is effective in reducing the incidence of diabetes-related foot ulcers. Home foot temperature monitoring also appears beneficial but larger trials are needed (PROSPERO registration no.: CRD42019135226).

Improving medical student empathy: Initial findings on the use of a book club and an old age simulation suit

Introduction

Empathy is critical to the development of professionalism in medical students, but evidence suggests that empathy actually declines over the course of undergraduate medical education.

Objectives

Improving medical student empathy by encouraging students to think about the person behind the illness.

Methods

Two interventions were studied. From December 2015 until November 2016, a fourth year psychiatry medical student book club was conducted. Students were asked to read an autobiography of a lived experience of psychosis. The old age simulation suit aims to simulate the sensory and physical impairments faced by older adults with age related illnesses. A training session provided a transient experience of old age for the students.

Results

Forty-four students completed the feedback on the book club. Twenty-eight (64%) stated that they strongly agreed with the statement ‘the book club encouraged me to consider the person behind the illness’. Thirty-nine (89%) stated that after attending the book club their empathy towards people with mental health problems had increased. Eleven students completed full feedback following the old age simulation session. Empathy statements relating to living in an ageing body improved from the pre-test median score of 4 (range 1–7) to a median score of 6 (range 2–8) post-teaching session. Empathy statements focusing on sensory and physical impairments had pre-test score median of 3 (range 1–7) and post-test median 8 (range 3–9).

Conclusions

Feedback from these sessions has demonstrated that with a little creativity, empathy training can be delivered to medical students with a positive impact.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

The effect of a community based health promotion intervention to change gender norms among women in a rural community in Sri Lanka

BACKGROUND

Gender norms practiced by respective societies increase the risk of violence by men against women. To date, there is a dearth of research evidence on changing gender norms through health promotion approaches around the globe, including in Sri Lanka. This study provides an evaluation of effectiveness of a health promotion intervention in changing the acceptance of gender norms among women.

METHODS

A quasi-experimental study was conducted in two rural villages in Anuradhapura district in Sri Lanka including women who have a child under five years of age. One village was allocated to receive an intervention developed based on a health promotion approach and the other village was a control. A community based mechanism to question selected gender norms among women was developed as the intervention. The pre- and post-intervention assessments of the level of acceptance of gender norms were done using an interviewer administered questionnaire and by using focus group discussions.

RESULTS

Following the intervention, acceptances of prominent gender norms were changed significantly among the women receiving the intervention method. The control group showed no changes towards the acceptance of gender norms during this period. Women in the intervention group had higher levels of self-reported positive behavior changes and greater understanding of gender concepts compared to the control group.

CONCLUSION

The acceptance of gender norms among women in rural villages in Sri Lanka can be changed by a community based intervention targeting gender norms.

Learning by doing, learning by seeing: Does observation of clinical simulation still count?

Introduction

Role-playing scenarios are widely used in psychiatry education, both as a means of assessment and for teaching various clinical skills. But can you get as much from them by learning vicariously as an observer? Fourth-year medical students from Queen Mary University of London were invited to a psychiatry practice OSCE (objective structured clinical examination), shortly before end of year exams. We created 96 places, approximately 40% of the year, but to maximize numbers students also rotated through the six-station OSCE circuit in pairs. For each scenario students alternated either undertaking the OSCE task or observing.

Objectives and methods

We sought to identify if there was a significant difference in student experience depending on whether they were the ‘candidate’ or ‘observer’. Students were asked to rate their learning experience in each station on a five-point Likert scale and this was analyzed using an ordinal logistic regression model.

Results

While students rated their experiences as ‘observers’ marginally lower than that of ‘candidates’, we found no statistically significant difference (OR = 0.629, P = 0.093). Practice OSCEs took place over six half-days with different facilitators and role-players, but we identified no interaction from these factors. For one station on depression, we found a statistically significant interaction in which ‘candidates’ rather than ‘observers’ rated better experiences (P = 0.032).

Conclusions

Observation by learners is frequently used within simulated clinical scenarios and may have a number of potential advantages. However, while unable to examine the direct impact on knowledge or skills, we found no significant difference in student-reported experiences between ‘candidate’ and ‘observer’ positions.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Construction of Cell-based Neurotransmitter Fluorescent Engineered Reporters (CNiFERs) for Optical Detection of Neurotransmitters In Vivo

Cell-based neurotransmitter fluorescent engineered reporters (CNiFERs) provide a new tool for neuroscientists to optically detect the release of neurotransmitters in the brain in vivo. A specific CNiFER is created from a human embryonic kidney cell that stably expresses a specific G protein-coupled receptor, which couples to Gq/11 G proteins, and a FRET-based Ca(2+)-detector, TN-XXL. Activation of the receptor leads to an increase in the FRET signal. CNiFERs have nM sensitivity and a temporal response of seconds because a CNiFER clone utilizes the native receptor for a particular neurotransmitter, e.g., D2R for dopamine. CNiFERs are directly implanted into the brain, enabling them to sense neurotransmitter release with a spatial resolution of less than one hundred µm, making them ideal to measure volume transmission in vivo. CNiFERs can also be used to screen other drugs for potential cross-reactivity in vivo. We recently expanded the family of CNiFERs to include GPCRs that couple to Gi/o G proteins. CNiFERs are available for detecting acetylcholine (ACh), dopamine (DA) and norepinephrine (NE). Given that any GPCR can be used to create a novel CNiFER and that there are approximately 800 GPCRs in the human genome, we describe here the general procedure to design, realize, and test any type of CNiFER.

A Parapharyngeal Soft Tissue Chordoma Presenting with Synchronous Cervical Lymph Node Metastasis: An Unusual Presentation

A 63 year old male presented with a three month history of dysphagia, neck swelling and an oropharyngeal swelling on examination. Initial fine needle aspiration cytology and magnetic resonance imaging (done at a peripheral hospital) suggested a salivary gland neoplasm with lymph node metastasis. An infra-temporal approach was employed to excise the tumour mass and a modified radical neck dissection undertaken to remove the cervical metastasis. Histopathological examination with immunohistochemistry confirmed this to be a soft tissue chordoma. To the best of our knowledge, this is the first documented report of an extra-axial soft tissue chordoma presenting with synchronous metastatic disease. Though rare, this adds to the list of differential diagnoses for complex parapharyngeal lesions. A multidisciplinary approach between head and neck surgery, histopathology, radiology and sarcoma teams is paramount for arriving at the correct diagnosis and to deliver optimal treatment.

Specialist integrated haematological malignancy diagnostic services: an Activity Based Cost (ABC) analysis of a networked laboratory service model

AIMS

Specialist Integrated Haematological Malignancy Diagnostic Services (SIHMDS) were introduced as a standard of care within the UK National Health Service to reduce diagnostic error and improve clinical outcomes. Two broad models of service delivery have become established: 'co-located' services operating from a single-site and 'networked' services, with geographically separated laboratories linked by common management and information systems. Detailed systematic cost analysis has never been published on any established SIHMDS model.

METHODS

We used Activity Based Costing (ABC) to construct a cost model for our regional 'networked' SIHMDS covering a two-million population based on activity in 2011.

RESULTS

Overall estimated annual running costs were £1 056 260 per annum (£733 400 excluding consultant costs), with individual running costs for diagnosis, staging, disease monitoring and end of treatment assessment components of £723 138, £55 302, £184 152 and £94 134 per annum, respectively. The cost distribution by department was 28.5% for haematology, 29.5% for histopathology and 42% for genetics laboratories. Costs of the diagnostic pathways varied considerably; pathways for myelodysplastic syndromes and lymphoma were the most expensive and the pathways for essential thrombocythaemia and polycythaemia vera being the least.

CONCLUSIONS

ABC analysis enables estimation of running costs of a SIHMDS model comprised of 'networked' laboratories. Similar cost analyses for other SIHMDS models covering varying populations are warranted to optimise quality and cost-effectiveness in delivery of modern haemato-oncology diagnostic services in the UK as well as internationally.

Pregnancy, contraception and emergency contraception: the language of urban adolescent young women

OBJECTIVE

We sought to characterize how a group of urban adolescent females understands the domains of pregnancy, contraception, and emergency contraception (EC).

DESIGN

We used the research strategy of freelisting as part of an in-depth interview study.

SETTING AND PARTICIPANTS

Urban adolescent females presenting to a Pediatric Emergency Department. Participants were enrolled using a purposive sampling strategy if they were black, English-speaking females, 15-19 years old, who resided in 1 of 11 zip codes surrounding the hospital.

MAIN OUTCOME MEASURE

Smith's saliency score. Freelists were analyzed for the entire sample, as well as for subgroups.

RESULTS

Thirty adolescents completed the interview. We found that this group of adolescents uses different words to characterize the domains of pregnancy, contraception, and EC. The only overlapping salient term was "abortion," which appeared in the overall lists for pregnancy and EC and in the younger group's list for contraception. In addition, lack of knowledge was cited as an important factor related to contraception.

CONCLUSIONS

Adolescent patients may not fully understand the concepts of contraception and EC. Providers should consider the potential need to provide an explanation for terms used, and they should consider explicitly differentiating between routine forms of contraception and EC, as well as between EC and abortion.

Plasma cell granuloma of the thyroid: a conservative approach to a rare condition and review of the literature

Introduction. We present a case of an 89-year-old female who attended our surgical endocrine clinic with a 3-month history of a left-sided neck lump. There was no past medical history of thyroid disease. Methods. Following examination and further investigation, including core biopsy, a diagnosis of plasma cell granuloma of the thyroid was made. Biochemical testing of thyroid function and Thyroid Peroxidase Antibody was in-keeping with an associated Hashimoto's thyroiditis. Results. The patient was treated conservatively with thyroxine and regularly seen in clinic. TSH levels improved and the lump showed signs of regression. Conclusion. Plasma cell granuloma of the thyroid is rare with only 16 previously reported cases. We present a new approach to management without the use of surgery or steroids. The literature is reviewed comparing clinico-pathological features and management of other reported cases.

Endostatin inhibits angiogenesis by stabilization of newly formed endothelial tubes

Endostatin decreased vascular endothelial growth factor (VEGF)-induced formation of endothelial tubes and microvessels sprouting from aortic rings and blocked their network. After cessation of treatment, the survival time of endostatin plus VEGF-treated tubes was approximately doubled in comparison to VEGF alone. Endostatin antibody blocked VEGF-induced endothelial tube formation and disrupted existing tubes. Endostatin immunostaining was localized between endothelium and basement membrane and in inter-endothelial junctions of new, but not of quiescent, blood vessels. In tumors grown in SCID mice, endostatin immunostaining was stronger accompanying blood vessel maturation and was significantly prominent in vessels of tumor marginal zone where angiogenesis is highly active. These data indicate a new antiangiogenic action of endostatin stabilizing and maturating endothelial tubes of newly formed blood vessels. Thus, strategies accelerating vascular stabilization and maturation could be promising in tumor therapy.

Psoriasis: response to high-dose intravenous immunoglobulin in three patients

Treatment of recalcitrant psoriasis and psoriatic arthritis can be challenging, with treatment options limited by drug intolerance or poor efficacy. High-dose intravenous immunoglobulin (hdIVIg) has been used successfully in Kawasaki's disease and idiopathic thrombocytopenic purpura, where it has become the standard treatment. The literature also suggests its positive effect in the treatment of dermatological conditions, such as autoimmune chronic urticaria, atopic dermatitis, scleromyxoedema, dermatomyositis and autoimmune bullous disorders. We report three patients with treatment-resistant psoriasis and psoriatic arthritis who improved with hdIVIg.

Transforming events in thyroid tumorigenesis and their association with follicular lesions

Thyroid tumors comprise a broad spectrum of neoplastic phenotypes, and distinct molecular events have been implicated in their pathogenesis. Pituitary tumor transforming gene, originally isolated from GH(4) pituitary cells, is tumorigenic in vivo, regulates basic fibroblast growth factor secretion, and is homologous to a securin inhibitor of chromatid separation. Pituitary tumor transforming gene 1 is expressed at low levels in several normal human tissues and is abundantly expressed in neoplasms, including colorectal carcinoma, where pituitary tumor transforming gene expression correlated highly with tumor invasiveness. As pituitary tumor transforming gene is regulated by E and as thyroid cancer shows a strong female preponderance, we examined pituitary tumor transforming gene 1 expression and action in human thyroid tumors and in normal human and rat thyroid cells. Increased pituitary tumor transforming gene 1 expression was evident early in thyroid tumors and was most abundantly expressed in a subset of thyroid hyperplasia, follicular adenomas, and follicular carcinomas (1.8-fold; P < 0.0001). Pituitary tumor transforming gene 1 overexpression in rat FRTL5 thyroid cells and in primary human thyroid cell cultures causes in vitro transformation and produces a dedifferentiated neoplastic phenotype. As pituitary tumor transforming gene 1 was abundantly overexpressed in follicular adenoma and follicular carcinoma, we propose that pituitary tumor transforming gene overexpression may play a role in the early molecular events leading to divergent development of follicular and papillary carcinoma.

Identification of colchicine in placental blood from patients using herbal medicines

While characterizing natural antiinflammatory substances in human placental blood, we discovered a factor that affected human neutrophils and their adherence. Rigorous chemical and stereochemical analyses revealed this factor to be the well-known alkaloid, colchicine. When samples from individual patients were analyzed, significant levels (49-763 microg/L) of colchicine could be found in placental blood of patients using nonprescription herbal dietary supplements during pregnancy. We confirmed the presence of colchicine in commercially available ginkgo biloba. Due to its potential harmful effects, it would appear that such supplements should be avoided by women who are pregnant or are trying to conceive.

CEA-related cell adhesion molecule 1: a potent angiogenic factor and a major effector of vascular endothelial growth factor

CEA-related cell adhesion molecule 1 (CEACAM1) exhibits angiogenic properties in in vitro and in vivo angiogenesis assays. CEACAM1 purified from granulocytes and endothelial cell media as well as recombinant CEACAM1 expressed in HEK293 cells stimulate proliferation, chemotaxis, and capillary-like tube formation of human microvascular endothelial cells. They increase vascularization of chick chorioallantoic membrane and potentiate the effects of vascular endothelial growth factor (VEGF)165. VEGF165 increases CEACAM1 expression both on the mRNA and the protein level. VEGF165-induced endothelial tube formation is blocked by a monoclonal CEACAM1 antibody. These data suggest that CEACAM1 is a major effector of VEGF in the early microvessel formation. Since CEACAM1 is expressed in tumor microvessels but not in large blood vessels, CEACAM1 may be a target for the inhibition of tumor angiogenesis.

CCR5 genotype and HIV-1 infection in perinatally-exposed infants

The CCR5 chemokine receptor is required by non-syncytium HIV-1 strains to infect target cells. A 32 base pair deletion (delta32) in the CCR5 gene causes a structural CCR5 modification that does not permit HIV-1 entry into cells. The rate of the CCR5 delta32 was investigated in 137 children born from HIV-infected mothers. Overall, five (10.6%) of 47 HIV-infected infants showed the defect in heterozygosis vs. eight (8.9%) of 90 uninfected children. No CCR5 delta32 homozygotes were found. Interestingly, among infected children, five (21.7%) of 23 showing a slow disease progression were heterozygous for the CCR5 delta32, meanwhile none of the 24 infants with rapid disease course had the deletion (P = 0.022). In conclusion, the CCR5 delta32 defect does not protect against vertical HIV-1 transmission, but is associated with a delayed disease progression in HIV-infected children.

Malaria in Honiara, Solomon Islands: reasons for presentation and human and environmental factors influencing prevalence

During February and March 1995, out-patients attending health clinics and the Central Hospital in East Honiara, Guadalcanal, Solomon Islands, were surveyed with the aim of determining factors influencing the differing rates of malaria, the proportion of transmission occurring within the town, and the reasons for presentation. Three hundred and nine adult patients, who were sick and had blood smears taken, were asked about their general knowledge of malaria transmission. Of those interviewed, 120 were visited at their home in East Honiara, to determine variables. EpiInfo 5.1 was used in analysis. A history of fever alone was not a good indicator of parasitemia. Most precautions, including bed nets, window screens and personal precautions were of little benefit. Significant protection was afforded individuals and families with indoor kitchens. Patients not completing their antimalarial treatment fared worse in terms of parasitemia and malaria history. Most malaria/parasitemia was indigenous to Honiara. Many patients had a good knowledge of malaria transmission and mosquitos, but this did not translate into a lower rate of parasitemia or malaria.

Malaria in Honiara, Solomon Islands: vector studies

Adult and larval specimens of anopheline mosquitos were collected throughout eastern Honiara during a study into risk factors for malaria illness in adults. Species identification was by morphology, DNA probes and by PCR. Only Anopheles farauti s.s. were identified from part-night landing catches carried out from 1900 to 2200 hours. Most mosquitos attracted to humans were culicines. The majority of anophelines (85%) were captured between 1900 and 2000 hours. An. farauti s.s. larvae were most common but one An. farauti No. 7, and ten An. punctulatus larvae were also collected.

Protective measure use and symptoms among agropesticide applicators in Sri Lanka

Sri Lankan farmers use large amounts of pesticides to control the pests affecting their vegetable crops. Improper use of pesticides by farmers has resulted in poisoning of occupational origin. This paper examines the use of protective measures by pesticide applicators and its relationship to their illness symptoms. The data were collected by interviewing a stratified random sample of 150 farmers from predominantly vegetable growing areas of the Matale district during 1990/91 using structured questionnaires. These data were supplemented with secondary data and observation of all stages of pesticide application. Scales were constructed to measure the domains of material style of life, awareness and use of protective measures, and illness symptoms experienced by pesticide applicators. It was found that most of the farmers were aware of the protective measures to be used when applying pesticides. There was, however, no significant positive relationship between awareness and use of protective measures. The main reason for not using protective measures was discomfort. The most common symptoms reported by pesticide applicators were faintish feeling, headache and dizziness. A significant negative relationship was observed between use of protective measures and symptoms exhibited within four hours of application. It is recommended that protective materials adapted to the climate and socio-economic conditions of farmers be developed, and that farmers be encouraged to use these protective materials through appropriate educational efforts and incentives.

De Novo Synthesis of Plasma Membrane and Tonoplast Polypeptides of Barley Roots during Short-Term K Deprivation : In Search of the High-Affinity K Transport System

[(35)S]Methionine labeling of intact barley roots (Hordeum vulgare cv Klondike) after short (6-12 h) and longer (18-24 and 90-96 h) periods of K(+) deprivation revealed that several membrane polypeptides were synthesized in significantly increased amounts following withdrawal of K(+) from nutrient solutions. One of these, a 43-kD polypeptide localized in plasma membrane- and tonoplast-enriched fractions, accounted for a large part of (35)S incorporation into membranes when [(35)S]methionine was administered for 6 h following 6 h of K(+) deprivation. With increasing duration of K(+) deprivation, (35)S incorporation into this 43-kD polypeptide decreased. This polypeptide, referred to as KR43, was not synthesized when NO(3) (-) or inorganic phosphate was removed or when Rb(+) was substituted for K(+). However, it was synthesized when K(+) was removed and replaced by an equivalent concentration of Na(+). The intrinsic nature of this polypeptide and the time course of changes in its expression, which correspond with changes of K(+)((86)Rb) influx associated with K(+) deprivation, provide evidence that this polypeptide may form part of the high-affinity K(+) transport system in barley roots. A possible role for this polypeptide is discussed in the context of changes in the subcellular distribution of K(+) in barley roots following interruption of K(+) supply. A 45-kD microsomal polypeptide, identified in earlier studies as a response to K(+) deprivation, is suggested to be an extrinsic protein, readily displaced from membranes by exposure to ethylenediaminetetraacetate.

Immunofluorescent Localization of Plasma Membrane H-ATPase in Barley Roots and Effects of K Nutrition

The plasma membrane H(+)-ATPase (PM-H(+)-ATPase) of barley (Hordeum vulgare L. cv Klondike) roots was assayed by cross-reaction on western blots and cryosections with an antibody against the PM-H(+)-ATPase from corn roots. Under conditions of reduced K availability, which have previously been shown to increase K influx by greater than 25-fold, there were only minor changes detected in PM-H(+)-ATPase levels. Antibody labeling of cryosections showed the relative distribution of PM-H(+)-ATPase among cell types in root tips and mature roots. Epidermal cells, both protoderm and mature root epidermis, including root hairs, had high levels of antibody binding. In mature roots, the stelar tissue showing the highest antibody binding was the companion cells of the phloem, followed by pericycle, xylem parenchyma, and endodermis.

Immersion warming of blood before transfusion

We compared a simple method of warming stored blood by immersion of blood bags in warm water, to the standard method using portex blood warming infusion coils, which are not freely available in Sri Lanka. The mean temperature of blood after warming by immersion of blood bags was 29.5 degrees C and by infusion coil 30.2 degrees C. The values were within the confidence limits of each other. Ten units of blood in each group were compared with regard to changes in free haemoglobin (Hb), packed cell volume (PCV), and hydrogen ion concentration, and no statistically significant difference was observed. We recommend immersion warming as a safe and effective alternative to warming by infusion coil.

Potassium-dependent changes in the expression of membrane-associated proteins in barley roots : I. Correlations with k(rb) influx and root k concentration

Barley (Hordeum vulgare L. cv Halcyon) seedlings which had been grown in full strength complete inorganic nutrient media (containing 6 millimolar K(+)) had high internal K(+) concentrations and low values of K(+) ((86)Rb(+)) influx when influx was measured from solutions containing 100 micromolar K(+). Transfer of these plants to solutions lacking K(+) resulted in significant reductions of root and shoot K(+) concentrations and values of K(+) ((86)Rb(+)) influx increased by greater than 10-fold within 3 days. When plants treated in this way were returned to complete solutions, containing K(+), the changes induced by K(+) deprivation were reversed. Parallel studies of microsomal membranes by means of SDS-PAGE demonstrated that the expression of a group of polypeptides increased or decreased in parallel with changes of K(+) ((86)Rb(+)) influx. Most prominent of these were 45 and 34 kilodalton polypeptides which specifically responded to K(+) status of the barley plants; their expression was not enhanced by N or P deprivation. The 45 kilodalton polypeptide was susceptible to degradation by a membrane associated protease when microsomes were washed in buffer containing 0.2 millimolar PMSF. This loss was prevented by increasing PMSF concentration to 2 millimolar.

Studies of the Regulation of Nitrate Influx by Barley Seedlings Using NO(3)

Using (13)NO(3) (-), effects of various NO(3) (-) pretreatments upon NO(3) (-) influx were studied in intact roots of barley (Hordeum vulgare L. cv Klondike). Prior exposure of roots to NO(3) (-) increased NO(3) (-) influx and net NO(3) (-) uptake. This ;induction' of NO(3) (-) uptake was dependent both on time and external NO(3) (-) concentration ([NO(3) (-)]). During induction influx was positively correlated with root [NO(3) (-)]. In the postinduction period, however, NO(3) (-) influx declined as root [NO(3) (-)] increased. It is suggested that induction and negative feedback regulation are independent processes: Induction appears to depend upon some critical cytoplasmic [NO(3) (-)]; removal of external NO(3) (-) caused a reduction of (13)NO(3) (-) influx even though mean root [NO(3) (-)] remained high. It is proposed that cytoplasmic [NO(3) (-)] is depleted rapidly under these conditions resulting in ;deinduction' of the NO(3) (-) transport system. Beyond 50 micromoles per gram [NO(3) (-)], (13)NO(3) (-) influx was negatively correlated with root [NO(3) (-)]. However, it is unclear whether root [NO(3) (-)] per se or some product(s) of NO(3) (-) assimilation are responsible for the negative feedback effects.