What supports and services post COVID-19 do children with disabilities and their parents need and want, now and into the future?

Introduction

Children and youth with disabilities and special healthcare needs, and their families, have been uniquely affected by the COVID-19 pandemic. However, the voices of children themselves are still not well represented in the existing literature.

Methods

This qualitative descriptive study used a combination of visual methods and interviews to learn about the experiences of Canadian children with disabilities (n=18) and their parents (n=14) during the COVID pandemic and into the post-pandemic period. Data collection was carried out between January and July 2023. The aim was to identify the supports and services children and families need at present and moving forward.

Results

Families' pandemic experiences were complex and nuanced. For many, the pandemic complicated and disrupted everyday activities and supports. These disruptions were largely buffered by parents. However, some families also identified unexpected benefits. Key themes pertaining to present and future needs included the need for services that are flexible; consistent; conducive to relationship-building; comprehensive; coordinated across sectors; and designed to support the needs of the whole family.

Discussion

Implications for policy and practice are outlined.

A comparative study into the effects of venous and arterial blood on clot microstructure in critically unwell patients. Assessment of the diagnostic potential of a biomarker of haemostasis

Blood for coagulation analysis can be sampled from the arterial or venous system in intensive care units (ICU). The determination of clot microstructure and strength by fractal analysis (df) gives valuable information in a range of vascular haemostatic disease and sepsis. We aimed to determine if df could be measured equally and comparatively in arterial or venous blood, and 45 critically ill patients in an ICU were recruited. df was found to be readily measured in arterial blood with results comparable to those in venous blood and that add value of df as a potential marker of haemostasis in these patients.

The efficacy of low molecular weight heparin is reduced in COVID-19

BACKGROUND

A significant degree of mortality and morbidity in COVID-19 is through thromboembolic complications, only partially mitigated by anticoagulant therapy. Reliable markers of infection severity are not fully established.

OBJECTIVES

This study investigated whether visco-elastic biomarkers predict disease severity on presentation to the Emergency Department (ED) and how they measure response to anticoagulationMETHODS:Patients testing positive for COVID-19 at a large University Teaching Hospital ED were recruited at presentation. Multiple blood samples were taken throughout hospital admission to monitor disease progression with end outcome recorded. Visco-elastic markers, fractal dimension (df) and Time to Gel Point (TGP) which measure the properties of the incipient clot were compared in patients with and without anticoagulation by Low Molecular Weight Heparin (LMWH).

RESULTS

TGP and df did not predict severity of infection with COVID-19. Although LMWH prolonged TGP, there was no change in df indicating LMWH did not change clot microstructure.

CONCLUSIONS

Therapeutic efficacy of LMWH appears blunted in COVID-19 infection. This may be due to the inflammatory state creating a resistance to LMWH activity, which may explain why LMWH appears less effective in COVID-19 compared to other disease states. COVID-19 was not predicted by visco-elastic testing at the time of ED presentation.

The Impact of Patient Characteristics and Antiplatelet Regimes on Clot Microstructure in Patients Treated for ST Elevation Myocardial Infarction: Clot Microstructure can Evaluate Therapeutic Efficacy

BACKGROUND

Unfavourable clot microstructure is associated with adverse outcomes in ST elevation myocardial infarction (STEMI). We investigated the effect of comorbidities and anti-platelet treatment on clot microstructure in STEMI patients using fractal dimension (d_f), a novel biomarker of clot microstructure derived from the visco-elastic properties of whole blood.

METHODS

Patients with STEMI (n = 187) were recruited sequentially receiving aspirin with Clopidogrel (n = 157) then Ticagrelor (n = 30). Patient characteristics and blood for rheological analysis obtained. We quantified d_f using sequential frequency sweep tests to obtain the phase angle of the Gel Point which is synonymous with the clot microstructure.

RESULTS

Higher d_f was observed in males (1.755 ± 0.068) versus females (1.719 ± 0.061, p = .001), in patients with diabetes (1.786 ± 0.067 vs 1.743 ± 0.046, p < .001), hypertension (1.760 ± 0.065 vs 1.738 ± 0.069, p = .03) and previous MI (1.787 ± 0.073 vs 1.744 ± 0.066, p = .011) compared to without. Patients receiving Ticagrelor had lower d_f than those receiving Clopidogrel (1.708 ± 0.060 vs 1.755 ± 0.067, p < .001). Significant correlation with d_f was found with haematocrit (r = 0.331, p < .0001), low-density lipoprotein (LDL) (r = 0.155, p = .046) and fibrinogen (r = 0.182, p = .014). Following multiple regression analysis, diabetes, LDL, fibrinogen and haematocrit remained associated with higher d_f while treatment with Ticagrelor remained associated with lower d_f.

CONCLUSIONS

The biomarker d_f uniquely evaluates the effect of interactions between treatment and underlying disease on clot microstructure. STEMI patients with diabetes and elevated LDL had higher d_f, indicating denser clot. Ticagrelor resulted in a lower d_f than Clopidogrel signifying a less compact clot.

High levels of soluble RAGE are associated with a greater risk of mortality in COVID-19 patients treated with dexamethasone

Blood levels of the soluble receptor for advanced glycation end-products (sRAGE) are acutely elevated during the host inflammatory response to infection and predict mortality in COVID-19. However, the prognostic performance of this biomarker in the context of treatments to reduce inflammation is unclear. In this study we investigated the association between sRAGE and mortality in dexamethasone-treated COVID-19 patients. We studied 89 SARS-CoV-2 positive subjects and 22 controls attending the emergency department of a University Teaching Hospital during the second wave of COVID-19 and measured sRAGE at admission. In positive individuals sRAGE increased with disease severity and correlated with the National Early Warning Score 2 (Pearson’s r = 0.56, p < 0.001). Fourteen out of 72 patients treated with dexamethasone died during 28 days of follow-up. Survival rates were significantly lower in patients with high sRAGE (> 3532 pg/mL) than in those with low sRAGE (p = 0.01). Higher sRAGE levels were associated with an increased risk of death after adjustment for relevant covariates. In contrast, IL-6 did not predict mortality in these patients. These results demonstrate that sRAGE remains an independent predictor of mortality among COVID-19 patients treated with dexamethasone. Determination of sRAGE could be useful for the clinical management of this patient population.

Impaired fibrinolysis in severe Covid-19 infection is detectable in early stages of the disease

BACKGROUND

A significant degree of mortality and morbidity in Covid-19 is due to thromboembolic disease. Coagulopathy has been well described in critically unwell patients on ICU. There is less clear evidence regarding these changes at the time of presentation to the Emergency Department and the progression of disease over time.

OBJECTIVE

We sought to investigate whether coagulation markers can predict severity and how they change over the disease course.

METHODS

Patients presenting to a single University Teaching Hospital were recruited and followed up if PCR was positive. Alongside routine blood testing, Rotational Thromboelastometry (ROTEM) was performed. Outcome data was recorded for all patients, and ROTEM values were compared across outcome groups.

RESULTS

Extem and Intem Maximum Lysis were significantly reduced in those who died or required an ICU admission, indicating a reduced ability to break down clot mass in the most critically unwell patients.

CONCLUSION

Comparisons between groups demonstrated that one distinguishing feature between those who require ICU admission or die of Covid-19 compared with those who survive a hospital stay to discharge was the extent to which fibrinolysis could occur. Mortality and morbidity in Covid-19 infection appears in part driven by an inability to break down clot mass.

The effects of apixaban on clot characteristics in atrial fibrillation: A novel pharmacodynamic biomarker

Atrial fibrillation (AF) is a major risk factor for stroke. We aim to characterize AF patients and the effects of apixaban therapy in terms of clot microstructure using gel point analysis, a novel biomarker. Seventy-eight patients were included in the study, 50 Stroke with AF (AF-S), and 28 AF without stroke (AF). Pre- and post-anticoagulation samples were collected: gel point (GP) analysis was performed to obtain (i) TGP (the time taken to reach the GP or the clot formation time) and (ii) d_{f ,} the fractal dimension of the clot, a quantification of clot fibrin microstructure at the GP. At baseline, the AF-S group had a d_f  = 1.70 (±0.05) and TGP = 306 (±73 s). The AF group had a df = 1.70 ± 0.05 and TGP = 346 ± 78 s, showing a significantly shortened TGP in the stroke group (p = .008). For both groups, apixaban significantly prolonged TGP, p = .005, but resulted in no change in df. Apixaban prolonged clotting time while having no significant impact on the blood's ability to form stable clots (no change in d_f ). This indicates that apixaban provides protection from the formation of thrombi by reducing clotting kinetics.

The effect of diabetic ketoacidosis (DKA) and its treatment on clot microstructure: Are they thrombogenic?

BACKGROUND

Diabetic ketoacidosis (DKA) is a medical emergency with a high mortality rate and is associated with severe metabolic acidosis and dehydration. DKA patients have an increased risk of arterial and venous thromboembolism, however little is known about this metabolic derangement in the first 24 hours of admission and to assess its effect on coagulation. We therefore utilised a novel functional marker of clot microstructure (fractal dimension - df) to assess these changes within the first 24 hours.

METHODS

Prospective single centre observational study to demonstrate whether the tendency of blood clot formation differs in DKA patients.

RESULTS

15 DKA patients and 15 healthy matched controls were recruited. Mean df in the healthy control group was 1.74±0.03. An elevated df of 1.78±0.07 was observed in patients with DKA on admission. The mean pH on admission was 7.14±0.13 and the lactate was 3.6±2.0. df changed significantly in response to standard treatment and was significantly reduced to 1.68±0.09 (2-6& h) and to 1.66±0.08 at 24& h (p < 0.01 One-way ANOVA). df also correlated significantly with lactate and pH (Pearson correlation coefficient 0.479 and -0.675 respectively, p < 0.05).

CONCLUSIONS

DKA patients at presentation have a densely organising less permeable thrombogenic clot microstructure as evidenced by high df. These structural changes are due to a combination of dehydration and a profound metabolic acidosis, which was reversed with treatment. These changes were not mirrored in standard clinical markers of thromboge-nicity.

The treatment effect of rivaroxaban on clot characteristics in patients who present acutely with first time deep vein thrombosis

BACKGROUND

The acute vascular disease deep vein thrombosis (DVT) requires oral anticoagulants to prevent progression. Monitoring therapeutic efficacy of direct oral anticoagulants (DOAC), including rivaroxaban, is problematic as no reliable test is available. Advances in rheometry have led to the development of a functional coagulation biomarker using Gel Point (GP) analysis which assesses clot structure formation. The biomarker measures incipient clot formation time (TGP) and quantifies fibrin clot structure in terms of fractal dimension (df).

OBJECTIVE

This study aimed to investigate clot structure formation in first time DVT and the effect of rivaroxaban treatment.

METHODS

This prospective observational cohort study measured the GP and standard laboratory markers at three sample points: pre-treatment and at 20 and 60 days following 15 mg BD and 20 mg OD rivaroxaban respectively.

RESULTS

Forty DVT patients (mean age 64 years [SD±14.8]; 23 males, 17 female) were recruited. The results show that DVT vs non-DVT patients did not have a significantly different GP profile (df: 1.72±0.06 vs 1.70±0.06 and TGP: 267±68 sec vs 262±73 sec) with both within the defined healthy index. In addition, rivaroxaban therapy increased TGP to 392 s (±135 s) after 20 days, and subsequently increased to 395 s (±194 s) at 60 days but did not significantly increase df (from 1.69±0.05 to 1.71±0.06).

CONCLUSIONS

The results indicate in this cohort of DVT patients there was no underlying hypercoagulable effect as determined by gel point analysis. Furthermore, the anticoagulant effect of rivaroxaban prolonged clotting, suggesting a protective effect against clot formation, without significantly reducing clot microstructural properties.

The effect of tyramine infusion and exercise on blood flow, coagulation and clot microstructure in healthy individuals

BACKGROUND

The long term benefits of exercise on the cardiovascular status of a patient have been proven, however, their benefit/risk relationship with exercise intensity is unclear. Furthermore, many thromboembolic diseases such as myocardial infarction and ischaemic stroke are associated with profound catecholamine release. In this study we explore the relationship between catecholamine release and hemodynamic changes and their effect on coagulation.

MATERIALS AND METHODS

Twelve healthy recreationally active males were recruited. Local anesthesia was given and catheters were placed under aseptic conditions, in the femoral artery and vein of the experimental leg. The first experiment involved tyramine infusion into the femoral artery at a dose of 1.0 μmol·min^-1·L leg volume^-1. The second experiment involved single leg knee-extensor exercise performed at 30 W for 15 min. Venous blood was collected at each time point to assess clot microstructure using the d_f biomarker.

RESULTS AND CONCLUSIONS

Tyramine infusion causes a local noradrenaline release in the leg. The increase in noradrenaline was associated with a significant increase in clot microstructure formation (d_f increased from 1.692 ± 0.029 to 1.722 ± 0.047, p = 0.016). Additionally moderate intensity single leg knee extensor exercise, which minimally alters sympathetic activity, also induced an increases in d_f (from 1.688 ± 0.025 to 1.723 ± 0.023, p = 0.001). This suggests that exercise can alter clot microstructure formation both via an increase in catecholeamine levels and by factors related to muscle activity per se, such as increased blood flow and consequent shear. These findings have implications for recommendations of exercise in patients at risk of cardiovascular events.

Epidemiology of burns and scalds in children presenting to the emergency department of a regional burns unit: a 7-year retrospective study

BACKGROUND

Variation in the incidence and mechanism of thermal injury has been reported in different age groups in children. The aim of this study was to report the incidence, mechanisms, and environmental factors of all burns presentations to the emergency department (ED) of a regional burns centre over a 7-year period.

METHODS

A retrospective, chart review study of all burns presentations to the ED of a regional burns centre in South Wales was conducted. All children recorded as having sustained a burn or scald, aged less than 16 years were included in the analysis. Subjects' demographics were analysed using descriptive statistics, and comparisons were made between patients aged less than 5 and patients aged 5-16 using chi-square test and Mann-Whitney U test.

RESULTS

A total of 1387 cases were included in the final analysis. Scalds were the most common thermal injury with 569 (41.0 %) reported, followed by contact burns in 563 (40.6 %) patients. The patients requiring hospitalisation were significantly younger (2 vs 3 years; p < 0.001) and had a higher rate of non-accidental injury (10 vs 4; p < 0.001). The most commonly injured site in both age groups was a hand or digit.

CONCLUSIONS

Scalds and contact burns were the most commonly reported thermal injury in children aged less than 16. Common mechanisms were hot beverages, hobs and hair straighteners, highlighting further burn prevention strategies are needed and good-quality prospective studies that investigate the effectiveness of such strategies.

Effectiveness of etoposide chemomobilization in lymphoma patients undergoing auto-SCT

The effectiveness of stem cell mobilization with G-CSF in lymphoma patients is suboptimal. We reviewed our institutional experience using chemomobilization with etoposide (VP-16; 375 mg/m(2) on days +1 and +2) and G-CSF (5 μg/kg twice daily from day +3 through the final day of collection) in 159 patients with lymphoma. This approach resulted in successful mobilization (>2 × 10(6) CD34+ cells collected) in 94% of patients (83% within 4 apheresis sessions). Fifty-seven percent of patients yielded at least 5 × 10(6) cells in 2 days and were defined as good mobilizers. The regimen was safe with a low rate of rehospitalization. Average costs were $14 923 for good mobilizers and $27 044 for poor mobilizers (P<0.05). Using our data, we performed a 'break-even' analysis that demonstrated that adding two doses of Plerixafor to predicted poor mobilizers at the time of first CD34+ cell count would achieve cost neutrality if the frequency of good mobilizers were to increase by 21%, while the frequency of good mobilizers would need to increase by 25% if three doses of Plerixafor were used. We conclude that chemomobilization with etoposide and G-CSF in patients with lymphoma is effective, with future opportunities for cost-neutral improvement using novel agents.

Usefulness of the hematopoietic cell transplantation-specific comorbidity index (HCT-CI) in predicting outcomes for adolescents and young adults (AYAs) with hematologic malignancies (HM) undergoing allogeneic stem cell transplant (alloSCT)

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Background: The HCT-CI was developed to help predict overall survival (OS) and non-relapse mortality (NRM) in pts undergoing alloSCT, a procedure with significant toxicity. AYAs with cancer (ages 16–40) have been identified by the NCI as a high-risk group, but it is not known whether the HCT-CI is a useful predictor of outcomes in this relatively healthy population. Methods: All pts ages 16–39 at the time of alloSCT from 1992–2008 were included. HCT-CI was retrospectively calculated for pts with complete data available. Univariable Cox regression models were used to examine the association between covariates and OS and NRM. Results: 62 evaluable pts included 38 males and 24 females. 50 (81%) were Caucasian, 9 (15%) African American, and 3 (5%) other. Diseases included AML (23), CML (14), ALL (14), and other (11). All comorbidities had a frequency of <5% in this population except for pulmonary dysfunction (69%), hepatic dysfunction (27%), infection (19%), and psychiatric disturbance (10%). When dichotomized into categories of 0–2 (32) and >3 (30), the HCT-CI was significantly associated with OS (p = 0.0006) and marginally with NRM (p = 0.07). Because pulmonary dysfunction appeared to be the most important contributor to the HCT-CI, the diffusing capacity adjusted for hemoglobin and alveolar volume (DLCO/VA adj) was examined independently. When dichotomized into categories of <80% and >80% of normal, the DLCO/VA adj alone was also significantly associated with OS (p = 0.008), but not with NRM (p = 0.2). Conclusions: AYAs with HM undergoing alloSCT have a limited number of comorbidities in the HCT-CI. Pulmonary dysfunction is most prevalent, and the DLCO/VA adj alone appears to be nearly as predictive for OS as the HCT-CI. The discrepancy between the predictiveness for OS and NRM may reflect pre-treatment or disease status of this population at the time of transplant.

No significant financial relationships to disclose.

Prognostic impact of bone marrow CD138 immunohistochemistry (IHC) prior to autologous stem cell transplant (ASCT) for multiple myeloma (MM)

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Background: Low bone marrow plasma cell (BMPC) burden prior to ASCT for MM is associated with favorable outcomes, but is usually determined by morphologic evaluation of marrow aspirates, a method subject to variability in sampling and interpretation. It is unknown if CD138 IHC, a more sensitive measure of BMPC, predicts progression-free survival (PFS), overall survival (OS) or post-ASCT response. Methods: Consecutive patients (n=93) who underwent single ASCT for MM from 2001 to 2008 and had available, stainable bone marrow core biopsies (BMB) obtained <90 days prior to ASCT were included in this single-center retrospective cohort study. BMB and/or clot CD138 IHC staining were reviewed by blinded hematopathologists. Post-ASCT response, PFS, and OS were determined using the International Myeloma Working Group uniform response criteria. Results: Patients were highly cytoreduced prior to ASCT, with 50.5% of pts having 0–5%, 21.5% having 6–10%, 20.4% having 11–20%, and 7.5% having >20% BMPC by CD138 analysis. BMPC% by CD138 IHC correlated with aspirate BMPC% [Pearson correlation coefficient=0.48, 95%CI (0.30, 0.63)]. In 12.6% of patients, BMPC% by CD138 IHC was ≥10% more than the aspirate count. Patients with ≤5% BMPC were more likely to achieve or maintain a CR or VGPR at initial post-ASCT restaging than those with >5% BMPC: Odds Ratio (95% CI) 6.91 (2.12, 22.57), p=. 0005 (chi-squared). With median follow up of 15.4 months for the ≤5% BMPC group and 19.3 months for the >5% BMPC group, 34/93 patients have progressed or died, with no difference between groups. By Kaplan-Meier analysis, PFS was similar regardless of BMPC [3 year estimated PFS (95%CI): ≤5%BMPC, 49.9% (29.4, 70.4) vs. >5%BMPC, 45.5% (26.7, 64.3); HR=1.24 (0.62, 2.49), p=.55, log-rank]. There was no difference in OS [3 year estimated OS (95%CI): ≤5%BMPC, 71.0% (49.7, 92.3) vs. >5%BMPC, 81.8% (66.2, 97.4); HR=0.61 (0.21, 1.78), p=.36, log-rank]. Conclusions: Detection of ≤5% BMPC by CD138 IHC prior to ASCT predicts attainment or maintenance of post-transplant CR/VGPR and correlates with plasma cell morphology. Differences in PFS or OS may emerge with additional follow-up, or if more patients with a higher content of residual plasma cells were transplanted.

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Dynamic imaging of the lungs using x-ray phase contrast

High quality real-time imaging of lungs in vivo presents considerable challenges. We demonstrate here that phase contrast x-ray imaging is capable of dynamically imaging the lungs. It retains many of the advantages of simple x-ray imaging, whilst also being able to map weakly absorbing soft tissues based on refractive index differences. Preliminary results reported herein show that this novel imaging technique can identify and locate airway liquid and allows lung aeration in newborn rabbit pups to be dynamically visualized.

Electrochemical monitoring of transport by a vesicular monoamine transporter expressed in Xenopus oocytes

Xenopus laevis oocytes were injected with synthetic mRNA coding for a rat VMAT2 mutant (rVMAT2-I483A/L484A) shown previously to be retained on the plasma membrane as a result of a presumed reduction of endocytosis. Binding of the specific VMAT inhibitor [3H]dihydrotetrabenazine indicated that expression did occur at a level of approximately 3 fmol per oocyte. To determine if rVMAT2-I483A/L484A expressed in oocytes was capable of substrate transport, oocytes were placed in buffer at pH 6.0, dopamine substrate was injected into the cell, and egress of substrate was monitored by fast scan cyclic voltammetry using a carbon fiber microelectrode. Under these conditions, transport by oocytes injected with RNA coding for rVMAT2-I483A/L484A ranged from approximately 0.5 to more than 2.5 pmol/min. Water-injected and uninjected control oocytes did not exhibit appreciable transport activity. Transport by rVMAT2-I483A/L484A-injected oocytes was reduced to control levels by tetrabenazine, a known inhibitor of VMAT transport activity. Comparison of subtracted voltammograms obtained from transport assays with those for calibration experiments confirmed that the transported species was dopamine. These results suggest that expression of VMATs in oocytes may provide a useful model system for mechanistic and regulatory studies that would not be feasible using traditional methods.

Two decades of orphan product development

Over the past 20 years, incentives of the Orphan Drug Act (ODA), the largest single source of extramural clinical grants at the US Food and Drug Administration, have had a substantial impact on public health. ODA incentives have contributed to the development of many innovative biotechnology products, and as our understanding of the human genome evolves, it is anticipated that pharmacogenomics will result in the identification of more 'orphan diseases'.

Active immunoneutralization of somatostatin in the sheep: effects on gastrointestinal somatostatin expression, storage and secretion

In the absence of somatostatin antagonists, somatostatin antisera administered acutely or animals chronically immunized against somatostatin have been used to define the functions of somatostatin. However, the circulating immunoglobulins from immunized animals may contain substantial quantities of endogenous hormones. This has not been examined for somatostatin. We have measured the amount of free somatostatin bound to circulating immunoglobulins in somatostatin-immunized animals and the effect of this sequestering of the free peptide on somatostatin secretion and gastric somatostatin synthesis and storage. The average concentration of somatostatin bound to the antisera was 6.9 nmol/l, about 1000-fold higher than normal circulating levels. Compared to control animals, there was a doubling of somatostatin mRNA in the fundus and a 4-fold increase in fundic somatostatin peptide. Similar increases were seen in pancreas, but the antrum was not significantly affected providing further evidence of distinct regulatory mechanisms between the antrum and fundus. We suggest that withdrawal of active somatostatin activates a regulatory loop to increase fundic somatostatin biosynthesis and storage. The data support the concept that somatostatin autoregulates its own expression at both the RNA and peptide level.

Adenoviral expression of murine serum amyloid A proteins to study amyloid fibrillogenesis

Serum amyloid A (SAA) proteins are one of the most inducible acute-phase reactants and are precursors of secondary amyloidosis. In the mouse, SAA1 and SAA2 are induced in approximately equal quantities in response to amyloid induction models. These two isotypes differ in only 9 of 103 amino acid residues; however, only SAA2 is selectively deposited into amyloid fibrils. SAA expression in the CE/J mouse species is an exception in that gene duplication did not occur and the CE/J variant is a hybrid molecule sharing features of SAA1 and SAA2. However, even though it is more closely related to SAA2 it is not deposited as amyloid fibrils. We have developed an adenoviral vector system to overexpress SAA proteins in cell culture to determine the ability of these proteins to form amyloid fibrils, and to study the structural features in relation to amyloid formation. Both the SAA2 and CE/J SAA proteins were synthesized in large quantities and purified to homogeneity. Electron microscopic analysis of the SAA proteins revealed that the SAA2 protein was capable of forming amyloid fibrils, whereas the CE/J SAA was incapable. Radiolabelled SAAs were associated with normal or acute-phase high-density lipoproteins (HDLs); we examined them for their clearance from the circulation. In normal mice, SAA2 had a half-life of 70 min and CE/J SAA had a half-life of 120 min; however, in amyloid mice 50% of the SAA2 cleared in 55 min, compared with 135 min for the CE/J protein. When the SAA proteins were associated with acute-phase HDLs, SAA2 clearance was decreased to 60 min in normal mice compared with 30 min in amyloidogenic mice. Both normal and acute-phase HDLs were capable of depositing SAA2 into preformed amyloid fibrils, whereas the CE/J protein did not become associated with amyloid fibrils. This established approach opens the doors for large-scale SAA production and for the examination of specific amino acids involved in the fibrillogenic capability of the SAA2 molecule in vitro and in vivo.

Foetal metabolism, placental transfer and origin of gastrin releasing peptide in the sheep

1. Plasma gastrin releasing peptide (GRP) is elevated in the foetal and maternal circulations of pregnant sheep. To determine the mechanisms for this increase the synthesis, secretion rate, metabolism and placental transfer of GRP were measured. 2. Foetal metabolic clearance rate of GRP was significantly increased (P < 0.05) compared to the non-pregnant ewe (19.9 +/- 2.6 (s.e.m.) and 11.8 +/- 2.0 mL/min per kg, respectively). Production rate of GRP in the foetus was four-fold higher than in the non-pregnant ewe reflecting the combination of the increased basal concentration and metabolic clearance rate in the foetus. 3. Infused GRP did not cross the placenta. However, endogenous GRP was higher in the umbilical vein than in the umbilical artery, suggesting a uteroplacental origin for some of the GRP in the foetal circulation. 4. Gastrin releasing peptide mRNA was synthesized in the pregnant endometrium with lower amounts found in the pregnant myometrium. No GRP mRNA was detected in the amnion or chorioallantois. 5. The results show that the previously reported increase in foetal concentration of GRP is from foetal and uteroplacental sources and is not a result of immaturity of clearance mechanisms but rather from an increased production of GRP. With the demonstration that the uteroplacental unit synthesizes and stores GRP, additional studies on the regulation of GRP production from these sources were warranted.

The pregnant ovine endometrium constitutively expresses and secretes a highly stable bombesin-like peptide, which shares C-terminal sequence but differs structurally from gastrin-releasing peptide

Previous studies have shown that a peptide closely related to gastrin releasing peptide (GRP) is expressed by the pregnant ovine endometrium throughout gestation, however its molecular form and the mode of its secretion have not been defined. We have partially purified the endometrial GRP-like peptide and characterised it chromatographically. In contrast to other tissues, the main molecular form of endometrial GRP is larger (6-8 kDa versus 1-3 kDa), and based on the increased hydrophobicity of its circulating form after reduction, contains at least one disulfide bond. Reduction and treatment with chaotropic agents showed that the protein is not a cleavage product of pro-GRP bound to a binding protein. Tryptic cleavage demonstrated that the C-terminus of the peptide is closely related to GRP18-27 suggesting that bioactivity is likely. The partially purified peptide remained intact after incubation in ovine plasma for 16 h indicating that it is extremely stable and consistent with an hormonal role during pregnancy. Quantification of peptide from monolayer cultures of ovine endometrial cells showed that the GRP-like peptide was secreted constitutively. These data show that a stable, GRP-like peptide, distinct from the known processing products of pre-pro-GRP is constitutively expressed by the gravid ovine endometrium. Since endometrial GRP has an intact bioactive C-terminus and is mitogenic for numerous tissues including the uterus, then it is likely to play an important regulatory role in ovine pregnancy.

A peptide related to gastrin releasing peptide is synthesised and secreted by the ovine endometrium in early pregnancy

We have previously shown that the peptide immunoreactivity related closely to the mitogen GRP is expressed by the pregnant ovine endometrium during the final third of pregnancy. In this study we have established that GRP is also expressed early in ovine pregnancy and have quantified the temporal changes in synthesis, storage and secretion of GRP in the peri- and post-attachment period. Secreted GRP peptide levels rise 10 fold just prior to implantation, while endometrial peptide and mRNA concentrations increase 4 and 13 fold respectively between day 17 and 20, immediately following attachment and corresponding to the onset of placentome development. The main molecular form of endometrial GRP has similar binding characteristics on RP-HPLC to GRP 18-27, but is larger. We conclude that a GRP-like peptide is expressed by the pregnant ovine endometrium from early in pregnancy until term, and that it is likely to play an important role in fetal or uterine maturation.

Bedside blood gas and electrolyte monitoring in critically ill patients

A major advantage of near-patient testing is time savings that facilitate important diagnostic and therapeutic decisions. Recent technologic advances have made available a number of systems that allow for near-patient testing. The reliability of these instruments must be validated in the clinical setting in the hands of their intended users. We evaluated the Gemstat blood gas, electrolyte, and Hct portable analyzer in the critical care setting when used by numerous individuals with no previous laboratory training. Blood gas, Na, K, and Hct results were highly correlated with those from the clinical laboratories (PaO2, r = .96; PaCO2, r = .92, pH, r = .96; Na, r = .93; K, r = .95; Hct, r = .91). The Gemstat represents a new generation of portable, rapid, safe, and accurate instruments that are well suited for ICU settings. The instrument can facilitate clinical management of patients, and may improve patient care.

Tumor volume and treatment outcome in small cell lung carcinoma

The volume of some tumors correlates with local disease control, response, and survival. Small cell lung carcinoma presents with variable and often large intrathoracic masses. We assessed volume by two methods (summation of cross-sectional areas and Simpson's rule for estimating volume) and correlated volume with treatment outcome. Twenty-nine patients with small cell lung carcinoma (12 limited disease and 17 extensive disease) were analyzed for volume outcome correlations. There were five early deaths. Twenty-four had response correlations (11 limited disease and 13 extensive disease). Eighteen of the twenty-four achieved complete response. There was no apparent correlation between complete and/or partial response and pretreatment tumor volume. There was no apparent correlation between survival and volume. The methods of volume assessment correlate well with each other (r = 0.88) and either can be used with accuracy. So far there is also no correlation between chest tumor volume and intrathoracic recurrence. Our projections suggest that there is a low probability of correlating chest tumor volume and either response or survival. This is in keeping with the disseminated nature of the tumor which is its limiting factor in survival.

Experimental simulation evaluation of ECG-gated heart scans with a small number of views

Computed tomography (CT) scanning techniques designed to visualize the beating heart utilize the electrocardiogram (ECG) waveform to gate or select the phase of the cardiac cycle being imaged. Most such methods require that each slice to be imaged be scanned many times to obtain the usual number of projections in a single phase interval of the cardiac cycle. We are studying a new method in which only a single scan of 20 s should be required per imaged slice. The central problem in the proposed technique is to test the diagnostic utility of images reconstructed from a very limited number (about 25) of projections. An essential part of the proposed algorithm is the elimination of all material outside a circle chosen to contain only the heart and the structures immediately surrounding it. Experiments are reported here on scans of calf's heart in an 11-cm container of water, with most views deleted so as to simulate the results from this type of gated scan. The results show that if no high-contrast objects are within the chosen circle, then image quality is satisfactory and could be clinically useful.

Liver injury and complications in the postoperative trauma patient: CT evaluation

Twenty-eight patients with surgically documented and classified hepatic injury were studied by computed tomography (CT) in the postoperative period. CT demonstrated no abnormalities in 12 of these patients, most of whom had sustained simple lacerations of the liver. Of the 16 patients with abnormal scans, perihepatic fluid collections were present in six, five of whom had simple lacerations at surgery. The other 10 patients had CT evidence of parenchymal abnormalities, and all of these had sustained major hepatic injuries. CT is useful in depicting the postoperative anatomy, and in many cases demonstrates the nature and extent of damage; the likelihood of finding an abnormality varies with the severity of the injury, even though repair has been attempted. The frequent problem of postoperative sepsis is also amenable to CT evaluation, but the changes demonstrated are often nonspecific and the possibility of residual hepatic injury has to be considered. Finally, CT can document healing of parenchymal injury.

Volume determinations in computed tomography

Modern computed tomographic (CT) scanners allow reasonably high-resolution cross-sectional visualization of most viscera and masses. To determine the accuracy of CT volume estimation, CT volumes of inanimate objects, cadaver kidneys and spleens, and in vivo balloons were performed. Regions of interest were outlined by a hand-operated cursor, and the computer program calculated the cross-sectional area in square millimeters and in pixels. A second computer program used Simpson's rule to calculate the volume from these multiple cross-sectional area. Calculated CT volumes were within +/-10% of directly measured volumes. Tumor masses being treated by chemotherapy were followed up clinically and by CT. Volume changes determined by CT are believed to be equal to and frequently more sensitive than clinical examination. From our experimental CT and clinical experiences, accuracy can be affected by (1) respiratory movement; (2) rapid changes in in vivo blood volume; (3) low CT number-gradient at the objects' periphery; (4) observer error in cursor tracing of the desired structure; and (5) mathematical errors inherent in Simpson's rule. We conclude that CT can estimate volumes of CT definable masses and can be useful in following tumor response to therapy.

Computed tomographic evaluation of carcinoma of the cervix

To assess the accuracy of computed tomography (CT) in staging advanced carcinoma of the cervix, 18 staging evaluations were performed in 16 patients with locally advanced (FIGO Stage IB-IVA) cervical carcinoma. CT staging results were compared with the results of clinical staging and postoperative staging. CT was accurate in 12/18 (66%) cases, clinical staging was accurate in 10/18 (55%) cases, and clinical staging with cystoscopy was accurate in 14/18 (78%) cases. CT staging failed to detect microscopic pelvic sidewall involvement and bladder involvement when there was no contrast material in the bladder. In the detection of para-aortic lymph node involvement by tumor, there were 12 true-negative, 4 true-positive, 1 false-positive, and 1 false-negative study (sensitivity = 80%, specificity = 92%). It is concluded that CT is equal in accuracy to other clinical staging techniques and offers the advantage of visualizing the tumor, which allows for more accurate determination of radiation portals.

Use of the computed tomographic whole body scanner to stage and follow patients with advanced ovarian carcinoma

Advanced ovarian carcinoma continues to be a difficult tumor to evaluate noninvasively. Recent developments in chemotherapy have enhanced response rates in this disease, thus improving the likelihood of tumor regression. Computed Tomography (CT) allows the noninvasive estimation of tumor extent in patients with ovarian carcinoma. Seventeen patients with epithelial ovarian carcinoma had 22 whole body CT scans performed either just prior to or following laparotomy. For determination of tumor involvement, when the CT was positive, a high pathologic correlation was found at liver, ascitic, peritoneal, mesenteric, and omental sites (sensitivity). When the cT was negative, high pathologic correlation was found at ascitic and mesenteric sites (specificity). Lower and negative correlation at other disease sites is attributed to difficulty of CT detection of small (1 cm) tumor nodules on visceral surfaces. Eighteen patients with advanced ovarian carcinoma were followed prospectively during treatment with repetitive CT scans. CT results were compared with physical examination, other radiologic studies, and clinical status. In 83% (15/18) of patients and 88% (59/67) of CT scans performed, CT was found to contribute useful management information. Clinical decisions were made on the basis of CT alone in 43% (29/67) of scans performed. These data suggest that CT scanning is very useful in the staging and follow-up of patients with ovarian carcinoma and can replace other radiologic procedures, but it is not completely accurate and needs to be correlated with physical examination and in cases without tumors visible with CT, with laparotomy.

Digital radiology in trauma using small-dose exposure

The microdose radiology system produces a large-field examination within thirty seconds on a video monitor. This video image can be manipulated in the same manner as a computed tomography (CT) scan. The system was installed at the Maryland Institute for Emergency Services (MIEMS) to examine severely injured patients. No major abnormalities were overlooked during the examination of these patients. The microdose system is useful in providing extensive radiologic information immediately applicable to the care of massively traumatized patients.

Effectiveness of small-group self-instruction in radiographic anatomy

A small-group self-instructional program with 11 slide-tape units was designed to teach medical students radiographic anatomy concurrently with their course in gross anatomy. The effectiveness of the program was examined by administering an objective multiple choice examination at three medical schools. One school offered the slide-tape program alone; one, the slide-tape program plus lecture-demonstrations; and one acted as a control. The results indicate that students will, on their own, learn some radiographic anatomy. With exposure to an objectives-based, small-group slide-tape program, the students can learn significantly more. Such a slide-tape program plus lecture-demonstrations can further enhance learning. Student attitudinal results were uniformly positive toward this slide-tape program.