Case Report: Hypergranular Platelets in Vaccine-Induced Thrombotic Thrombocytopenia After ChAdOx1 nCov-19 Vaccination

Background

Vaccine-induced thrombotic thrombocytopenia (VITT) post SARS-CoV-2 vaccination is characterized by thrombocytopenia and severe thrombosis. Platelet function during patient recovery in the medium-/long-term has not been investigated fully. Here, we undertook a 3-month study, assessing the recovery of a VITT patient and assessing platelet morphology, granule content and dense-granule release at two distinct time points during recovery.

Case Presentation

A 61 year-old female was admitted to hospital 15 days post ChAdOx1 nCov-19 vaccination. Hematological parameters and peripheral blood smears were monitored over 3 months. Platelet morphology and granule populations were assessed using transmission electron microscopy (TEM) at two distinct time points during recovery, as was agonist-induced platelet dense-granule release. Upon admission, the patient had reduced platelet counts, increased D-dimer and high anti-PF4 antibodies with multiple sites of cerebral venous sinus thrombosis (CVST). Peripheral blood smears revealed the presence of large, hypergranular platelets. Following treatment, hematological parameters returned to normal ranges over the study period. Anti-PF4 antibodies remained persistently high up to 90 days post-admission. Two days after admission, VITT platelets contained more granules per-platelet when compared to day 72 and healthy platelets. Additionally, maximal ATP release (marker of dense-granule release) was increased on day 2 compared to day 72 and healthy control platelets.

Conclusion

This study highlights a previously unreported observation of platelet hypergranularity in VITT which may contribute to the thrombotic risk associated with VITT. Optimal approaches to monitoring recovery from VITT over time remains to be determined but our findings may help inform therapeutic decisions relating to anticoagulation treatment in this novel pathology.

Long-term persistence of crAss-like phage crAss001 is associated with phase variation in Bacteroides intestinalis

BACKGROUND

The crAss-like phages are ubiquitous and highly abundant members of the human gut virome that infect commensal bacteria of the order Bacteroidales. Although incapable of lysogeny, these viruses demonstrate long-term persistence in the human gut microbiome, dominating the virome in some individuals.

RESULTS

Here we show that rapid phase variation of alternate capsular polysaccharides in Bacteroides intestinalis cultures plays an important role in a dynamic equilibrium between phage sensitivity and resistance, allowing phage and bacteria to multiply in parallel. The data also suggests the role of a concomitant phage persistence mechanism associated with delayed lysis of infected cells, similar to carrier state infection. From an ecological and evolutionary standpoint, this type of phage-host interaction is consistent with the Piggyback-the-Winner model, which suggests a preference towards lysogenic or other "benign" forms of phage infection when the host is stably present at high abundance.

CONCLUSION

Long-term persistence of bacteriophage and host could result from mutually beneficial mechanisms driving bacterial strain-level diversity and phage survival in complex environments.

Isolation and characterisation of ΦcrAss002, a crAss-like phage from the human gut that infects Bacteroides xylanisolvens

BACKGROUND

The gut phageome comprises a complex phage community of thousands of individual strains, with a few highly abundant bacteriophages. CrAss-like phages, which infect bacteria of the order Bacteroidales, are the most abundant bacteriophage family in the human gut and make an important contribution to an individual's core virome. Based on metagenomic data, crAss-like phages form a family, with four sub-families and ten candidate genera. To date, only three representatives isolated in pure culture have been reported: ΦcrAss001 and two closely related phages DAC15 and DAC17; all are members of the less abundant candidate genus VI. The persistence at high levels of both crAss-like phage and their Bacteroidales hosts in the human gut has not been explained mechanistically, and this phage-host relationship can only be properly studied with isolated phage-host pairs from as many genera as possible.

RESULTS

Faeces from a healthy donor with high levels of crAss-like phage was used to initiate a faecal fermentation in a chemostat, with selected antibiotics chosen to inhibit rapidly growing bacteria and selectively enrich for Gram-negative Bacteroidales. This had the objective of promoting the simultaneous expansion of crAss-like phages on their native hosts. The levels of seven different crAss-like phages expanded during the fermentation, indicating that their hosts were also present in the fermenter. The enriched supernatant was then tested against individual Bacteroidales strains isolated from the same faecal sample. This resulted in the isolation of a previously uncharacterised crAss-like phage of candidate genus IV of the proposed Alphacrassvirinae sub-family, ΦcrAss002, that infects the gut commensal Bacteroides xylanisolvens. ΦcrAss002 does not form plaques or spots on lawns of sensitive cells, nor does it lyse liquid cultures, even at high titres. In keeping with the co-abundance of phage and host in the human gut, ΦcrAss002 and Bacteroides xylanisolvens can also co-exist at high levels when co-cultured in laboratory media.

CONCLUSIONS

We report the isolation and characterisation of ΦcrAss002, the first representative of the proposed Alphacrassvirinae sub-family of crAss-like phages. ΦcrAss002 cannot form plaques or spots on bacterial lawns but can co-exist with its host, Bacteroides xylanisolvens, at very high levels in liquid culture without impacting on bacterial numbers. Video abstract.

Endoscopic Botulinum toxin as a treatment for delayed gastric emptying following oesophagogastrectomy

INTRODUCTION

The incidence of delayed gastric emptying (DGE) following oesophagogastrectomy with gastric conduit reconstruction is reported to be between 1.7% and 50%. This variation is due to differing practices of intraoperative pylorus drainage procedures, which increase the risk of postoperative biliary reflux and dumping syndrome, resulting in significant morbidity. The aim of our study was to establish rates of DGE in people undergoing oesophagogastrectomy without routine intraoperative drainage procedures, and to evaluate outcomes of postoperative endoscopically administered Botulinum toxin into the pylorus (EBP) for people with DGE resistant to systemic pharmacological treatment.

METHODS

All patients undergoing oesophagogastrectomy between 1 January 2016 and 31 March 2018 at our unit were included. No intraoperative pyloric drainage procedures were performed, and DGE resistant to systemic pharmacotherapy was managed with EBP.

RESULTS

Ninety-seven patients were included. Postoperatively, 29 patients (30%) were diagnosed with DGE resistant to pharmacotherapy. Of these, 16 (16.5%) were diagnosed within 30 days of surgery. The median pre-procedure nasogastric tube aspirate was 780ml; following EBP, this fell to 125ml (p<0.001). Median delay from surgery to EBP in this cohort was 13 days (IQR 7-16 days). Six patients required a second course of EBP, with 100% successful resolution of DGE before discharge. There were no procedural complications.

CONCLUSIONS

This is the largest series of patients without routine intraoperative drainage procedures. Only 30% of patients developed DGE resistant to pharmacotherapy, which was managed safely with EBP in the postoperative period, thus minimising the risk of biliary reflux in people who would otherwise be at risk following prophylactic pylorus drainage procedures.

Physiological Characteristics of Musical Theatre Performers and the Effect on Cardiorespiratory Demand Whilst Singing and Dancing

AIMS

Musical theatre (MT) combines acting, singing, and dancing within a performance. The purpose of the current study was two-fold: 1) to report on the cardiorespiratory fitness of pre-professional MT dancers, and 2) to examine the cardiorespiratory demand of singing whilst dancing.

METHODS

Twenty-one participants (16 females, 5 males; age 20±1.23 yrs; height 169.1±9.24 cm; weight 62.7±10.56) in their final year of pre-professional training volunteered for the study. All participants performed a maximal aerobic capacity test on a treadmill using a portable breath-by-breath gas analyser. Nine participants completed a 4-minute section from Chorus Line twice, singing and dancing and just dancing, in a randomised order whilst wearing the same portable gas analyser. Blood lactate was measured at the end of each trial.

RESULTS

Male participants had significantly greater peak oxygen consumption (M vs F, 67.6±2.30 vs 55.6±4.42 mL/kg/min, p<0.001) and anaerobic threshold (% of peak VO2) (54.6±4.04% vs 43.1±3.68%, p<0.001), whilst maximum heart rate and heart rate at anaerobic threshold were similar. The physiological demands of dancing vs singing + dancing were similar, with the exception of the singing + dancing trial having significantly reduced mean breathing frequency and increased lactate (p<0.01).

CONCLUSIONS

MT dancers' aerobic capacity is greater than that observed in other theatre-based dance genres. The observed breathing frequency and lactate differences in the Chorus Line trails could be due to singing reducing breathing frequency, thereby influencing cardiorespiratory recovery mechanics and subsequently blood lactate levels.

First case of a dog infected with Aspergillus (Phialosimplex) caninus in Australasia

Case history: A 2-year-old Rottweiler dog from Perth (WA, Australia) was referred for assessment of a chronic productive cough and weight loss.Clinical findings: Severely enlarged bilateral superficial cervical lymph nodes and severely enlarged abdominal organs were present. The body condition score was poor and there was moderate muscle wasting. Thoracic and abdominal computed tomography images revealed severe diffuse enlargement of thoracic and abdominal lymph nodes, hepatomegaly and diffuse splenomegaly. A diffuse bronchial pattern with severe multifocal saccular bronchiectasis was identified in the lungs.Diagnostic findings: Fungal organisms were seen within macrophages on cytological preparations and on histopathological sections of biopsies of the superficial cervical lymph node. Macrophages contained intracytoplasmic, non-filamentous round-to-ovoid organisms, which varied in size from 5-30 µm in diameter with variable morphology. Budding was not observed, and no hyphae were present. Fungal culture of lymph node tissue resulted in growth of Aspergillus (Phialosimplex) caninus which was confirmed by amplification and sequencing of a segment of the 16S-23S rRNA internal transcribed spacer. Concurrent bacterial bronchitis was diagnosed on culture of broncho-alveolar fluid.Diagnosis: Disseminated aspergillosis caused by Aspergillus caninus.Clinical relevance: This is believed to be the first report of infection caused by A. caninus in a dog in Australasia. The dog was treated with itraconazole for 7 months and was still alive 7 months after the start of treatment.

Animal and human health is unlikely to be at risk when generations of sheep graze bauxite residue (Alkaloam®)-amended pastures

Bauxite residue (Alkaloam®) applied to pasture has been shown significantly to improve pasture production on sub-fertile soil, such as those found in south-west Western Australia, because it increases soil pH. There are concerns that animals grazing Alkaloam-amended pasture may suffer ill health through heavy metal accumulation in tissues, and that this effect could be amplified over generations. There are additional concerns that eating exposed animals, or direct exposure to Alkaloam, may be detrimental to human health. Although some literature exists there are no studies that address these issues when the application of Alkaloam occurred several years (20) before grazing. This investigation examined the heavy metal and trace element accumulation in the tissues of Dorper lambs (1 year old) and their dams, Dorper ewes (4–5 years old) grazing Alkaloam-amended pasture. The experiment was conducted on two sites grazed in the Peel region of Western Australia: one site in Coolup, the Control site (Site C), that had had no application of Alkaloam and one site in Wagerup, the Treatment site (Site T), that had had 20 tonnes per hectare of Alkaloam applied in 1993. Both sites had uniform soil and pasture type during the growing season. Samples of soil and pasture were collected at each site. Differences in trace element concentrations, pH and conductivity between sites were determined. Ten ewes and 10 lambs were randomly selected at each site, removed and killed on the same day for gross examination of the kidney, liver and lung tissue. Samples of the tissues were collected for histopathological examination and chemical analysis to determine concentrations of trace elements. Depending on the concentration of trace elements in each sample, a logistical regression with binomial regression or an ANOVA was performed to determine differences in concentrations between ages, sites and any interactions between age and site. Sheep from Site T had significantly higher concentrations of copper, manganese and molybdenum, whereas sheep from Site C had significantly higher concentrations of cobalt, iron, lead, nickel, selenium, strontium and zinc in tissues. Ewes had significantly higher concentrations of barium, cadmium, cobalt, iron and strontium whereas lambs had significantly higher concentrations of copper, manganese and molybdenum in tissues. Ewes had higher concentrations of cadmium in the kidney compared with lambs, and ewes from Site C had significantly higher concentrations than ewes from Site T. Ewes and lambs from Site C had significantly higher concentrations of selenium in the liver compared with ewes and lambs from Site T. Concentrations of heavy metals (As, Hg, Pb, Th and U) were low in tissues of all sheep. The results show that whereas there were different elemental tissue concentrations between sites and between ages of sheep, there were no detrimental trace element imbalances or accumulation of heavy metals that would cause ill health in any of the sheep that could be associated with the application of Alkaloam to pasture. It is unlikely that humans will suffer any ill effects as a consequence of eating exposed animals. This result supports the premise that bauxite residue can be safely applied to pasture to significantly improve pasture and animal production where animals graze pasture growing on sub-fertile soil.

WITHDRAWN: Corrigendum to "The pathology and pathogenicity of a novel Haemoproteus spp. infection in wild Little Penguins (Eudyptula minor)" [Vet. Parasitol. 197 (1-2) (2013) 74-84]

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.vetpar.2014.07.021. The duplicate article has therefore been withdrawn.

Engineered biosynthesis of disaccharide-modified polyene macrolides

Recent work has uncovered genes for two glycosyltransferases that are thought to catalyze mannosylation of mycosaminyl sugars of polyene macrolides. These two genes are nypY from Pseudonocardia sp. strain P1 and pegA from Actinoplanes caeruleus. Here we analyze these genes by heterologous expression in various strains of Streptomyces nodosus, producer of amphotericins, and in Streptomyces albidoflavus, which produces candicidins. The NypY glycosyltransferase converted amphotericins A and B and 7-oxo-amphotericin B to disaccharide-modified forms in vivo. The enzyme did not act on amphotericin analogs lacking exocyclic carboxyl or mycosamine amino groups. Both NypY and PegA acted on candicidins. This work confirms the functions of these glycosyltransferases and provides insights into their acceptor substrate tolerance. Disaccharide-modified polyenes may have potential as less toxic antibiotics.

An unidentified lipid prevalent in tumors

An unidentified lipid was found in five different tumor sources. It was not found in liver, bone marrow or plasma from tumor-bearing animals, nor in the extracellular fluid supporting growth of Ehrlich ascites cells. The polarity of the unidentified component was similar to that of a glyceryl ether diester, and it was isolated in milligram amounts by preparative thinlayer chromatography. Neither methyl esters of fatty acids, vinyl ether diesters nor quinones were found in the structural makeup of this lipid. Thin-layer chromatography of the purified unidentified tumor lipid on Ag-impregnated silica layers revealed two main components of intermediary unsaturation. Saponification of the unidentified tumor lipid, when water washing was omitted, yielded two components that migrated at R(f)'s identical to those of free fatty acids and dihydroxy glyceryl monoethers. Neither acetate-1-(14)C nor palmitic-1-(14)C acid (single injections) was found to be incorporated into the unidentified lipid of a mature rat tumor.

MRI demonstrates the extension of juxta-articular venous malformation of the knee and correlates with joint changes

OBJECTIVE

Juxta-articular venous malformations (VMs) are uncommon, but may cause early arthropathy of the knee in children and adolescents. We sought to describe the prevalence, extent and initial magnetic resonance imaging (MRI) features of knee arthropathy in children with VM adjacent to the knee joint.

METHODS

Thirty-five patients with VM adjacent to the knee who had MRI performed between 2000 and 2009 were identified through a keyword search of the radiology information system.

RESULTS

VM extended to the joint in 17 of the 35 patients (5.4-21.5 years, mean 11.8 years). Most of these 17 patients had joint changes (15/17, 88%), most commonly haemosiderin deposition (14/17, 82%). Other findings included the presence of subchondral bone lesions (eight, 47%), cartilage loss (six, 35%), synovial thickening (six, 35%), marrow oedema (six, 35%), joint effusion (five, 29%), subchondral cysts (five, 29%) and one loose body (6%). VM location and size did not correlate with the degree of articular involvement. Joint changes were present in focal as well as non-discrete VM.

CONCLUSION

We found that the frequency of arthropathy increased with extension of VM into the joint itself. This finding stresses the importance of early MRI evaluation of all juxta-articular VM.

Treat the patient not the blood test: the implications of an increase in cardiac troponin after prolonged endurance exercise

Collapse after prolonged endurance exercise is common and usually benign. This case study reports a triathlete who suffered a vaso-vagal associated collapsed after exercise. Misdiagnosis of myocardial injury in the presence of elevated cardiac troponins and ECG anomalies led to inappropriate management and highlights the difficulty in treating the collapsed athlete following arduous exercise.

Spontaneous atrial fibrillation in a freestyle skier

A male freestyle skier was found to have atrial fibrillation during a routine physiological assessment. This was found to be associated with the consumption of an unusually large amount of alcohol. Athletes should be counselled about the potential dangers of alcohol consumption before exhaustive exercise.

The upper limit of physiological cardiac hypertrophy in elite male and female athletes: the British experience

Establishment of upper normal limits of physiological hypertrophy in response to physical training is important in the differentiation of physiological and pathological left ventricular hypertrophy. The genetic differences that exist in the adaptive response of the heart to physical training and the causes of sudden cardiac death in young athletes indicate the need for population-specific normal values. Between September 1994 and December 2001, 442 (306 male, 136 female) elite British athletes from 13 sports were profiled. Standard two-dimensional guided M-mode and Doppler echocardiography were employed to evaluate left ventricular morphology and function. Eleven (2.5%) athletes, competing in a range of sports including judo, skiing, cycling, triathlon, rugby and tennis, presented with a wall thickness >13 mm, commensurate with a diagnosis of hypertrophic cardiomyopathy. Eighteen (5.8%) male athletes presented with a left ventricular internal diameter during diastole (LVIDd) >60 mm, with an upper limit of 65 mm. Of the 136 female athletes, none where found to have a maximum wall thickness >11 mm. Left ventricular internal diameter was <60 mm in all female athletes. Systolic and diastolic function were within normal limits for all athletes. Upper normal limits for left ventricular wall thickness and LVIDd are 14 mm and 65 mm for elite male British athletes, and 11 mm and 60 mm for elite female British athletes. Values in excess of these should be viewed with caution and should prompt further investigation to identify the underlying mechanism.

Reducing conduct problems among children of battered women

This study was an experimental evaluation of an intervention designed to reduce conduct problems among children of battered women. Participants were 36 families (mothers and children) in which the mother had sought shelter because of relationship violence and had at least 1 child (4-9 years old) with clinical levels of conduct problems. The intervention consisted of 2 primary components: (a) providing instrumental and emotional support and (b) teaching child management skills to mothers. Families were randomly assigned to either the intervention condition or the existing services comparison condition and were assessed on 5 occasions over 16 months after shelter departure. Compared with families receiving existing services, children in the intervention condition improved at a faster rate, the proportion of children displaying clinical levels of conduct problems was greatly diminished, and mothers displayed greater improvements in child management skills.

Release of biologically active TGF-beta from airway smooth muscle cells induces autocrine synthesis of collagen

In severe or chronic asthma, there is an increase in airway smooth muscle cell (ASMC) mass as well as an increase in connective tissue proteins in the smooth muscle layer of airways. Transforming growth factor-beta (TGF-beta) exists in three isoforms in mammals and is a potent regulator of connective tissue protein synthesis. Using immunohistochemistry, we had previously demonstrated that ASMCs contain large quantities of TGF-beta1-3. In this study, we demonstrate that bovine ASMC-derived TGF-beta associates with the TGF-beta latency binding protein-1 (LTBP-1) expressed by the same cells. The TGF-beta associated with LTBP-1 localizes TGF-beta extracellularly. Furthermore, plasmin, a serine protease, regulates the secretion of a biologically active form of TGF-beta by ASMCs as well as the release of extracellular TGF-beta. The biologically active TGF-beta released by plasmin induces ASMCs to synthesize collagen I in an autocrine manner. The autocrine induction of collagen expression by ASMCs may contribute to the irreversible fibrosis and remodeling seen in the airways of some asthmatics.

Structure and in vitro function of human subcutaneous small arteries in mild heart failure

The structure and function of subcutaneous small arteries from patients with mild heart failure (n = 27) 6-43 mo after myocardial infarction were compared with vessels from healthy control subjects (n = 10). Patients were randomized to treatment with placebo or the angiotensin-converting enzyme inhibitor ramipril starting 3-10 days after myocardial infarction. Dissected arterial vessels were mounted on a wire myograph for measurement of morphology and isometric tension. Morphology was not different in arteries from the three groups. Responses to norepinephrine, angiotensin II, and electrical field stimulation were similar in arteries from placebo-treated patients with mild heart failure and control subjects. Similarly, endothelium-dependent and -independent relaxation was normal in arteries from patients with mild heart failure. Ramipril therapy was associated with functional alterations: vasoconstrictor responses to norepinephrine and angiotensin II were significantly enhanced compared with placebo (P < 0.001). These data suggest that vascular structure and function are not different in vitro in subcutaneous arteries from placebo-treated patients with mild heart failure. Angiotensin-converting enzyme inhibitor therapy is associated with enhanced vasoconstriction to norepinephrine and angiotensin II, which may reflect upregulation of receptor-mediated events.

Influence of isradipine and spirapril on left ventricular hypertrophy and resistance arteries

Left ventricular hypertrophy is a common clinical feature in hypertensive patients and may be associated with structural changes in vessel morphology. In an open prospective trial, we evaluated 14 patients with previously untreated hypertension (163 +/- 2/104 +/- 2 mm Hg) and an echocardiographically determined left ventricular mass index of 141.6 +/- 5.2 g/m2, indicating left ventricular hypertrophy. We obtained a gluteal skin biopsy sample before starting treatment to investigate subcutaneous small-artery (approximately 200 to 400 microns diameter) morphology and function. Patients then received antihypertensive treatment with a combination of spirapril (3 or 6 mg) and isradipine (2.5 or 5 mg). Echocardiographic recordings were made after 6 months and 1 year, and a final biopsy was taken after 1 year. After 1 year, blood pressure was significantly reduced to 142 +/- 3/ 90 +/- 1 mm Hg (P < .001), and left ventricular mass index decreased significantly to 105.3 +/- 5.8 g/m2 (P < .001). Baseline media-lumen ratio (7.64 +/- 0.48%) was not markedly reduced (7.21 +/- 0.55%), although a decrease occurred in 7 of 12 evaluable patients. Norepinephrine-induced vasoconstriction was markedly reduced after 1 year. In conclusion, a significant regression of left ventricular hypertrophy was obtained after 1 year of treatment with spirapril and isradipine, whereas a similar reduction in medial thickness relative to lumen diameter of subcutaneous small arteries could not be observed in all patients. Reversal of structural changes in resistance vessels may require a longer treatment period in patients with proven left ventricular hypertrophy.

Effect of antihypertensive treatment on small arteries of patients with previously untreated essential hypertension

In a double-blind randomized trial, the effects of treatment with an angiotensin-converting enzyme (ACE) inhibitor (perindopril) and a beta-blocker (atenolol) on small artery structure were compared in previously untreated essential hypertensive patients. Subjects (diastolic blood pressure > or = 100 and < or = 120 mm Hg) were randomly assigned to treatment for 12 months with either perindopril (n = 13, 4 to 8 mg/d) or atenolol (n = 12, 50 to 100 mg/d); the dosage was adjusted upward and in some cases combined (n = 5, perindopril; n = 2, atenolol) with thiazide diuretic to achieve target blood pressure (diastolic blood pressure below 90 mm Hg). Before and at the end of treatment, gluteal biopsies were taken under local anesthetic; from these biopsies, two small arteries were dissected and mounted on a myograph for morphometry. The reduction in blood pressure with atenolol (drop in mean blood pressure 28.4 +/- 1.8 mm Hg) was greater than with perindopril (20.6 +/- 1.8 mm Hg, P < .05). Perindopril treatment caused an increase in small artery diameter (231 +/- 14 to 274 +/- 13 microns, P < .05) and a reduction in the ratio of media thickness to lumen diameter (7.94 +/- 0.65% to 5.96 +/- 0.42%, P < .05), whereas atenolol had no effect (246 +/- 14 to 231 +/- 13 microns and 7.14 +/- 0.47% to 6.79 +/- 0.45%, respectively). The change in small artery morphology caused by perindopril was not accompanied by any change in media cross-sectional area, suggesting that the change was due to "remodeling."(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of small artery sensitivity and morphology in pressurized and wire-mounted preparations

Two in vitro techniques, the pressurized flow chamber and the wire myograph, commonly employed to study the structure and function of small arteries, were compared. Mesenteric arteries from Wistar-Kyoto (WKY) rats were studied at a transmural pressure (44 +/- 1 mmHg) at which they elicit optimum contraction in each system. Differences in morphological parameters were minor, but there was a marked difference in the vasoconstrictor response of arteries mounted in the wire myograph and pressure system. Endothelium-intact pressurized arteries were significantly more sensitive to norepinephrine and constricted to angiotensin II, whereas wire-mounted vessels did not. These differences in agonist-induced contraction remained after removal of the endothelium. Blockade of amine uptake mechanisms indicated that the difference in norepinephrine sensitivity between the systems resulted from an enhanced influence of neuronal amine uptake in wire-mounted arteries. These data demonstrate that the technique employed has important functional implications for the study of small artery responses in vitro and that the results of investigations into the pathophysiology of small arteries are dependent on the method used and must be interpreted with caution.

Neurotransmission in Human Resistance Arteries: Contribution of α1- and α2- Adrenoceptors but Not P2- Purinoceptors

The contribution of postjunctional alpha 1- and alpha 2-adrenoceptors and P2-purinoceptors to the neuroeffector response was examined in isolated segments of human subcutaneous resistance arteries. Electrical field stimulation (EFS, 20 V, 0.2 ms, 1-25 Hz) elicited a maximum contractile response which was 38.2 +/- 1.6% of that elicited by exogenously applied (5 microM) noradrenaline (n = 56). Tetrodotoxin (1 microM), used to inhibit neurotransmission, reduced the electrically evoked response to 24.7 +/- 4.4% (n = 10) of the control response. The alpha 1-adrenoceptor antagonist prazosin (1 microM) reduced the maximum EFS contractile response to 64.8 +/- 5.5% of the control response (n = 17). Application of the alpha 2-adrenoceptor antagonist yohimbine (0.1 microM) reduced the maximum EFS response to 68.2 +/- 8.2% of the control response (n = 9). In the presence of prazosin plus yohimbine at the above-mentioned concentrations the maximum response to EFS was reduced to 47.6 +/- 6.7% (n = 11). Responses following alpha-blockade were not statistically different from those in the presence of tetrodotoxin, but the mean responses indicate that a non-adrenergic component to the EFS response cannot be discounted. Desensitisation of P 2-purinoceptors with alpha, beta-methylene ATP had no effect on responses to EFS; therefore under the conditions studied these receptors do not appear to be involved in neurotransmission. These results confirm the presence of postjunctional alpha 1- and alpha 2-adrenoceptors in human resistance arteries and for the first time demonstrate that the postjunctional alpha 2-adrenoceptor is important in modulating vascular responses elicited by intramural sympathetic nerve fibres.

Arterial neuroeffector responses in early and mature spontaneously hypertensive rats

Intramural sympathetic neuroeffector responses and presynaptic regulation of neurotransmission by amine uptake and alpha 2-adrenergic receptors were examined in young (5-week-old) and mature (12-week-old) spontaneously hypertensive rats (SHR) and were compared with those of age-matched Wistar-Kyoto (WKY) control rats. Electrical field stimulation (20 V, 0.2-msec pulse width, 3-second pulse train each minute, 5-100 Hz) elicited contractile responses from isolated mesenteric arteries mounted in a myograph. There was a significant difference between the sensitivity of arteries to electrical field stimulation in the two age groups, with arteries from 12-week-old rats being more sensitive than arteries from 5-week-old animals. Also, there was a significant age-strain interaction: the sensitivity of arteries from SHR to electrical field stimulation increased dramatically with age compared with that of WKY rat arteries. Cocaine significantly increased the sensitivity to electrical field stimulation after inhibition of presynaptic alpha 2-adrenergic receptors, and had a significantly greater effect in arteries from 5-week-old SHR compared with WKY controls. This would reflect an overactive neuronal amine uptake mechanism in young SHR. At 12 weeks there was no significant interstrain difference in the effect of cocaine. Yohimbine increased the sensitivity to electrical field stimulation both before and after inhibition of neuronal amine uptake, but there was no difference in its effect with age or strain. Therefore, although sensitivity to sympathetic nerve stimulation varies with age in the SHR, there is no evidence that this can be ascribed to alpha 2-adrenergic receptor function.

Pulmonary vascular smooth muscle: biochemical and mechanical developmental changes

To evaluate the developmental changes in pulmonary vascular smooth muscle contractile protein content, mechanical properties, and their contribution to the high resistance characteristic of the fetal and immediate neonatal period, we studied pulmonary vessels of fetal, newborn, and adult sheep, as well as newborn and adult pigs. Strips of the second- through fifth-generation vessels were dissected, and their content of tissue total smooth muscle cell protein, myosin, and actin-to-myosin ratio were measured; the mechanical properties of the second-generation vascular strips were also studied. For all ages the smooth muscle protein and myosin content of the second-generation vessels were significantly greater than for the lower pulmonary vascular orders (P less than 0.05). The myosin content in fetal sheep (0.77 +/- 0.03 micrograms/mg wet tissue) was similar to that of the newborn (0.79 +/- 0.04) and adult (0.86 +/- 0.05). However, the smooth muscle protein content (7.94 +/- 0.21 micrograms/mg wet tissue) and the actin-to-myosin ratio of the pulmonary vascular tissue of the fetus (1.00 +/- 0.04) were lower (P less than 0.01) in the fetal than in the newborn (9.16 +/- 0.26 and 1.60 +/- 0.12) and adult (9.38 +/- 0.3 and 1.60 +/- 0.11, respectively). No differences were observed for these parameters between the newborn and adult pig. Stress (16.5 +/- 1.7 mN/mm2) and the maximum shortening capacity (13.0 +/- 1.5% of optimal length) in the newborn pulmonary vascular strips were significantly greater than for the fetus (6.8 +/- 1.4 and 5.9 +/- 1.0, respectively) but similar to those of the adult sheep.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous growth of the motor system in the axolotl

During growth of the axolotl, motor neurons, and muscle fibres are added to the motor system. By double labelling neurons with tritiated thymidine and retrogradely transported HRP, we show that some motor neurons are born at postembryonic stages. Further analysis of motor neurons with the aid of HRP reveals this population of newly born cells relatively frequently in small (5-7 cm long) axolotls, but only rarely in large (7-13 cm long) axolotls. Evidence is presented that suggests that these immature cells are in the process of migrating from close to the ependyma out to the ventral horn. HRP transport also reveals growth cones of advancing axons within spinal nerves in animals up to 6 cm in length. Cell counts by light and electron microscopic methods show that muscle fibres are generated throughout larval life in the iliotibialis, a typical limb muscle. This analysis provides data consistent with the notion that new muscle fibres are added from a localised growth zone situated at the superficial edge of the muscle. These results are discussed in terms of the correlation between continuous growth of the motor system and the ability of the axolotl to functionally repair lesions to the peripheral nervous system.

Effect of admission nutritional status on length of hospital stay

Malnutrition is a large problem among patients admitted to U.S. hospitals and is an area of increasing concern for GI health care professionals. We conducted a prospective assessment of the admission nutritional status of 500 consecutive patients admitted to the Huntington Veterans Affairs Medical Center. Admission nutritional status was compared to the length of hospital stay (LOS). Nutritional status was calculated based on three equally weighted and easily obtained parameters--serum albumin, total peripheral blood lymphocyte counts and unintentional weight loss over time. A significant difference (p less than 0.01) was noted for the LOS between patients with normal, mildly abnormal and moderately abnormal nutritional status as compared with the patients with severe malnutrition. The length of hospital stay progressively increased with deterioration of nutritional status. The GI practitioner is in a key position to assess nutritional status of hospitalized patients. If malnutrition can be documented on hospital admission, attempts can be made to reverse the malnutrition and hopefully diminish LOS.

The pattern of innervation in serially duplicated axolotl limbs: further evidence for the existence of local pathway cues?

The innervation of the biceps muscle was examined in regenerated and vitamin A-induced serially duplicated axolotl forelimbs using retrograde transport of horseradish peroxidase. The regenerated biceps muscle becomes innervated by motor neurones in the same position in the spinal cord as the normal biceps motor pool. In previous experiments in which the innervation of a second copy of a proximal limb muscle was examined in serially duplicated limbs (Stephens, Holder & Maden, 1985), the duplicate muscle was found to become innervated by motor neurones that would normally have innervated distal muscles. In the present study, the innervation of the second copy of biceps was examined under conditions designed to encourage nerve sprouting from ‘correct’ biceps axons. Following either partial limb denervation or denervation coupled with removal of the proximal biceps, the second copy of the muscle was still innervated by inappropriate motor neurones, which again would normally innervate distal limb muscles. These results are interpreted as evidence for the necessity for an appropriate local environment for axonal growth to allow reformation of a correct pattern of motor innervation in the regenerated limb.

Reformation of the pattern of neuromuscular connections in the regenerated axolotl hindlimb

Retrograde neuronal tracing with horseradish peroxidase (HRP) was used to determine the position in the spinal cord of motor neurone pools innervating muscles in the regenerated axolotl hindlimb. This method allows a detailed analysis of the accuracy of reformation of neuromuscular connections. The results show that regenerated distal limb muscles are reinnervated by motor neurones in the same region of the cord as those that innervate normal control distal limb muscles but that proximal muscles are innervated by a mixture of motor neurones in a normal position and motor neurones in a region of the spinal cord that normally supplies innervation to distal limb muscles. This difference between the reinnervation of proximal and distal limb muscles suggests that axons destined for proximal muscles may not enter distal limb territory during reinnervation of the regenerated limb.

Marketing to older American consumers

Older adults are examined as a potential market for American businesses. Data indicate that in terms of size and income, senior citizens comprise a substantial buying group. Their buying styles, product and service needs, and shopping behavior are shown to vary from those of younger adults and, in fact, vary substantially within the older adult population. Differences are speculated to be the result not only of age influence, but also of cohort and period influences. Strategies for successful marketing are suggested. These strategies relate directly to the identified characteristics of older adults.

Motorneuron pools innervating muscles in vitamin A-induced proximal-distal duplicate limbs in the axolotl

Serially duplicated limbs containing two sets of proximal muscles were created in axolotls by vitamin A treatment. The innervation of three replicated proximal muscles was studied by using retrograde transport of horseradish peroxidase. These were the forelimb muscles biceps (seven cases) and anconeus (five cases) and the hindlimb muscle puboischiotibialis (five cases). In two cases (both of anconeus) innervation was from a correct motorneuron pool. In the other 15 cases the innervation was from an incorrect, distal limb muscle, motorneuron pool. These results are interpreted as evidence against long range signals between nerve and muscle controlling specific nerve regeneration. However, the data are compatible with models of axonal guidance that use local pathway cues.

A horseradish peroxidase study of motorneuron pools of the forelimb and hindlimb musculature of the axolotl

Motorneuron pools innervating axolotl limb muscles have been investigated by using the retrograde neuronal tracer horseradish peroxidase. Four muscles in the forelimb (biceps, anconeus, flexor digitorum and extensor digitorum) and four functionally equivalent muscles in the hindlimb (puboischiotibialis, iliotibialis, flexor digitorum and extensor digitorum) were studied. Motorneuron pools were characterized by using four criteria: position in the rostrocaudal axis; position of the median in the rostrocaudal axis; number of labelled cells; position of cells in the transverse plane of the spinal cord. Each pool was uniquely defined by the four characteristics, although overlap was found between pools. Two types of motorneuron were found in each pool, distinguished on the basis of size, shape and position in the spinal cord. The first type constituted the majority of cells in a pool, and occupied different positions in the transverse plane for each muscle. The second type was less common and always occupied a characteristic medial ventral position. These data will allow an assay of correct or incorrect innervation in experiments on the regeneration of specific neuromuscular connections in these animals.

Quantitative analysis of ether-linked lipids as alkyl- and alk-1-enyl-glycerol benzoates by high-performance liquid chromatography

Methodology for the quantitative and qualitative analyses of alkyl- and alk-l-enyl-glycerols derived by Vitride reduction of ether-linked glycerolipids in the presence of an internal standard was developed. The procedure involved preparation of benzoate derivatives that were subsequently analyzed by high-performance liquid chromatography with detection at 228 nm. Separation of the glycerol ether dibenzoates on a C18 reverse-phase column allowed for the simultaneous quantitation and the determination of chain length of both alkyl- and alk-l-enyl-glycerols in a single chromatographic run of less than 15 min. The method was accurate (less than 10% error), reproducible, and sensitive (less than 1 microgram per component). Application of the method to the analysis of phospholipids from L-M cells grown in the presence and absence of elaidic acid demonstrated that the cells incorporated a portion of the trans acid supplement (presumably via the fatty alcohol) into the side chains of both alkyl- and alk-l-enyl-glycerol-containing phosphatides.

Airway smooth muscle mechanics: reduced activation and relaxation

Reduced activation of skeletal muscle fibers at below-optimal lengths has been reported before. We studied tracheal smooth muscle (TSM) as a model of airway smooth muscle to see whether such a phenomenon existed in smooth muscle also; we found that active length-tension curves at normal and raised Ca2+ concentrations were significantly different. This indicated reduced activation of the TSM at below-optimal lengths. This reduction was in addition to that arising from the length-tension effect. We also studied the mechanics of relaxation in TSM and noted that in afterloaded isotonic tension records the time course of TSM relaxation appeared to closely follow that of the isometric contraction at all loads. In this it differed markedly from relaxation in skeletal muscle where the time courses of relaxation at different loads differed from each other and from that of the isometric muscle.

The modification of lipid composition in L-M cultured cells supplemented with elaidate. Increased formation of fatty alcohols

Supplementation of culture medium with elaidic acid (40 micrograms/ml) resulted in the incorporation of this acid into 50% of the acyl groups of phospholipids in L-M cells; elaidate was esterified at both the sn-1 and the sn-2 positions of phosphatidylcholine and phosphatidylethanolamine. In addition, elaidate supplementation of L-M cells induces the accumulation of free fatty alcohols, alkyldiacylglycerols and wax esters/cholesterol esters. The concentration of intracellular free fatty alcohols increased as a function of the concentration of elaidic acid in the growth medium and the duration of exposure. However, the concentration of alcohol-containing lipids, total alkyl and alk-1-enyl lipids, was only slightly decreased. This decrease was much less than the increase in the level of free fatty alcohols. Therefore, we conclude that when elaidic acid is supplemented to L-M cells in culture, a net increase in the production of free fatty alcohols occurs.