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result(s) for
"Gradwell, D P"
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Calretinin positive neurons form an excitatory amplifier network in the spinal cord dorsal horn
by
Boyle, Kieran A
,
Callister, Robert J
,
Jobling, Phillip
in
Acute pain
,
Analgesics
,
Analgesics, Opioid - pharmacology
2019
Nociceptive information is relayed through the spinal cord dorsal horn, a critical area in sensory processing. The neuronal circuits in this region that underpin sensory perception must be clarified to better understand how dysfunction can lead to pathological pain. This study used an optogenetic approach to selectively activate spinal interneurons that express the calcium-binding protein calretinin (CR). We show that these interneurons form an interconnected network that can initiate and sustain enhanced excitatory signaling, and directly relay signals to lamina I projection neurons. Photoactivation of CR interneurons in vivo resulted in a significant nocifensive behavior that was morphine sensitive, caused a conditioned place aversion, and was enhanced by spared nerve injury. Furthermore, halorhodopsin-mediated inhibition of these interneurons elevated sensory thresholds. Our results suggest that dorsal horn circuits that involve excitatory CR neurons are important for the generation and amplification of pain and identify these interneurons as a future analgesic target. Despite being unpleasant, pain is critical to survival because it acts as a warning for damage or impending harm. Day-to-day pain like a stubbed toe or a pricked finger is called acute pain. It alerts the body to harm but only lasts a short time and usually goes away on its own. Pain that persists more than three months after the damaged tissue has healed is known as chronic pain, and it is a serious problem that is often difficult to treat. Learning more about the causes of chronic pain is necessary to help develop more effective therapies. Nerve pathways in the spinal cord help process pain and other sensory information from the skin and relay it to the brain. These pathways include sensory fibers that carry pain information from the body to the spinal cord, as well as cells that relay this information to the brain. But not much is known about how the nerves and cells in this region prioritize or refine sensory information before sending it to the brain. Now, Smith et al. have used mice to show that nerve cells in the spinal cord that produce the protein calretinin can act as a pain amplifier, causing it to persist. A technique called optogenetics was used to turn on calretinin nerve cells by exposing them to light. This caused the mice to behave like they were in pain even though they had not been harmed, and the behaviour stopped when they were treated with morphine, a powerful painkiller. Further experiments showed that calretinin nerve cells form a highly interconnected network in the spinal cord. These results show that calretinin nerve cells can ‘jump-start’ the pain pathway within the spinal cord, even when there is no painful stimulation of the skin. Turning on these cells even briefly causes behaviours associated with prolonged pain. By revealing that networks of calretinin nerve cells in the spinal cord act like an in-built pain amplifier, the experiments identify these cells as a potential target for new treatments for chronic pain.
Journal Article
IL-6–mediated endothelial injury impairs antiviral humoral immunity after bone marrow transplantation
by
Henden, Andrea S.
,
Legg, Samuel R.W.
,
Andoniou, Christopher E.
in
Allografts
,
Analysis
,
Animals
2024
Endothelial function and integrity are compromised after allogeneic bone marrow transplantation (BMT), but how this affects immune responses broadly remains unknown. Using a preclinical model of CMV reactivation after BMT, we found compromised antiviral humoral responses induced by IL-6 signaling. IL-6 signaling in T cells maintained Th1 cells, resulting in sustained IFN-γ secretion, which promoted endothelial cell (EC) injury, loss of the neonatal Fc receptor (FcRn) responsible for IgG recycling, and rapid IgG loss. T cell–specific deletion of IL-6R led to persistence of recipient-derived, CMV-specific IgG and inhibited CMV reactivation. Deletion of IFN-γ in donor T cells also eliminated EC injury and FcRn loss. In a phase III clinical trial, blockade of IL-6R with tocilizumab promoted CMV-specific IgG persistence and significantly attenuated early HCMV reactivation. In sum, IL-6 invoked IFN-γ–dependent EC injury and consequent IgG loss, leading to CMV reactivation. Hence, cytokine inhibition represents a logical strategy to prevent endothelial injury, thereby preserving humoral immunity after immunotherapy.
Journal Article
Cetuximab in the management of nasopharyngeal carcinoma – a narrative review
2019
Concurrent chemotherapy with radiotherapy is the standard treatment for locoregionally advanced nasopharyngeal cancer. Cetuximab can be used in the treatment of head and neck squamous cell carcinoma. However, the randomised studies that led to approval for its use in this setting excluded nasopharyngeal cancer. In the context of limited data for the use of cetuximab in nasopharyngeal cancer in the medical literature, this review aimed to summarise the current evidence for its use in both primary and recurrent or metastatic disease.
A literature search was performed using the keywords 'nasopharyngeal neoplasm', 'cetuximab' and 'Erbitux'.
Twenty studies were included. There were no randomised phase III trials, but there were nine phase II trials. The use of cetuximab in the treatment of nasopharyngeal carcinoma has been tested in various settings, including in combination with induction chemotherapy and concurrent chemoradiotherapy, and in the palliative setting.
There is no evidence of benefit from the addition of cetuximab to standard management protocols, and there is some evidence of increased toxicity. There is more promise for its use in metastatic or locally recurrent settings. This review draws together the existing evidence and could provide a focus for future studies.
Journal Article
Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33)
by
Turner, Robert C
,
Cull, Carole A
,
Holman, Rury R
in
Amputation
,
Angina
,
Biological and medical sciences
1998
Improved blood-glucose control decreases the progression of diabetic microvascular disease, but the effect on macrovascular complications is unknown. There is concern that sulphonylureas may increase cardiovascular mortality in patients with type 2 diabetes and that high insulin concentrations may enhance atheroma formation. We compared the effects of intensive blood-glucose control with either sulphonylurea or insulin and conventional treatment on the risk of microvascular and macrovascular complications in patients with type 2 diabetes in a randomised controlled trial.
3867 newly diagnosed patients with type 2 diabetes, median age 54 years (IQR 48–60 years), who after 3 months' diet treatment had a mean of two fasting plasma glucose (FPG) concentrations of 6·1–15·0 mmol/L were randomly assigned intensive policy with a sulphonylurea (chlorpropamide, glibenclamide, or glipizide) or with insulin, or conventional policy with diet. The aim in the intensive group was FPG less than 6 mmol/L. In the conventional group, the aim was the best achievable FPG with diet alone; drugs were added only if there were hyperglycaemic symptoms or FPG greater than 15 mmol/L. Three aggregate endpoints were used to assess differences between conventional and intensive treatment: any diabetes-related endpoint (sudden death, death from hyperglycaemia or hypoglycaemia, fatal or non-fatal myocardial infarction, angina, heart failure, stroke, renal failure, amputation [of at least one digit], vitreous haemorrhage, retinopathy requiring photocoagulation, blindness in one eye, or cataract extraction); diabetes-related death (death from myocardial infarction, stroke, peripheral vascular disease, renal disease, hyperglycaemia or hypoglycaemia, and sudden death); all-cause mortality. Single clinical endpoints and surrogate subclinical endpoints were also assessed. All analyses were by intention to treat and frequency of hypoglycaemia was also analysed by actual therapy.
Over 10 years, haemoglobin A1c (HbA1c) was 7·0% (6·2–8·2) in the intensive group compared with 7·9% (6·9–8·8) in the conventional group—an 11% reduction. There was no difference in HbA1c among agents in the intensive group. Compared with the conventional group, the risk in the intensive group was 12% lower (95% CI 1–21, p=0·029) for any diabetes-related endpoint; 10% lower (−11 to 27, p=0·34) for any diabetes-related death; and 6% lower (−10 to 20, p=0·44) for all-cause mortality. Most of the risk reduction in the any diabetes-related aggregate endpoint was due to a 25% risk reduction (7–40, p=0·0099) in microvascular endpoints, including the need for retinal photocoagulation. There was no difference for any of the three aggregate endpoints between the three intensive agents (chlorpropamide, glibenclamide, or insulin).
Patients in the intensive group had more hypoglycaemic episodes than those in the conventional group on both types of analysis (both p<0·0001). The rates of major hypoglycaemic episodes per year were 0·7% with conventional treatment, 1·0% with chlorpropamide, 1·4% with glibenclamide, and 1·8% with insulin. Weight gain was significantly higher in the intensive group (mean 2·9 kg) than in the conventional group (p<0·001), and patients assigned insulin had a greater gain in weight (4·0 kg) than those assigned chlorpropamide (2·6 kg) or glibenclamide (1·7 kg).
Intensive blood-glucose control by either sulphonylureas or insulin substantially decreases the risk of microvascular complications, but not macrovascular disease, in patients with type 2 diabetes. None of the individual drugs had an adverse effect on cardiovascular outcomes. All intensive treatment increased the risk of hypoglycaemia.
Journal Article
Observer variation in histopathological diagnosis and grading of cervical intraepithelial neoplasia
by
Newcombe, R. G.
,
Dinnen, J. S.
,
Evans, D. M.
in
Biopsies
,
Biopsy
,
Cervical intraepithelial neoplasia
1989
To assess the variability among histopathologists in diagnosing and grading cervical intraepithelial neoplasia eight experienced histopathologists based at different hospitals examined the same set of 100 consecutive colposcopic cervical biopsy specimens and assigned them into one of six diagnostic categories. These were normal squamous epithelium, non-neoplastic squamous proliferations, cervical intraepithelial neoplasia grades I, II, and III, and other. The histopathologists were given currently accepted criteria for diagnosing and grading cervical intraepithelial neoplasia and asked to mark their degree of confidence about their decision on a visual linear analogue scale provided. The degree of agreement between the histopathologists was characterised by kappa statistics, which showed an overall poor agreement (unweighted kappa 0.358). Agreement between observers was excellent for invasive lesions, moderately good for cervical intraepithelial neoplasia grade III, and poor for cervical intraepithelial neoplasia grades I and II (unweighted kappa 0.832, 0.496, 0.172, and 0.175, respectively); the kappa value for all grades of cervical intraepithelial neoplasia taken together was 0.660. The most important source of disagreement lay in the distinction of reactive squamous proliferations from cervical intraepithelial neoplasia grade I. The histopathologists were confident in diagnosing cervical intraepithelial neoplasia grade III and invasive carcinoma (other) but not as confident in diagnosing cervical intraepithelial neoplasia grades I and II and glandular atypia (other). Experienced histopathologists show considerable interobserver variability in grading cervical intraepithelial neoplasia and more importantly in distinguishing between reactive squamous proliferations and cervical intraepithelial neoplasia grade I. It is suggested that the three grade division of cervical intraepithelial neoplasia should be abandoned and a borderline category introduced that entails follow up without treatment.
Journal Article
Calretinin positive neurons form an excitatory amplifier network in the spinal cord dorsal horn
by
Boyle, Kieran A
,
Callister, Robert J
,
Jobling, Phillip
in
Analgesics
,
Aversion
,
Calcium-binding protein
2019
The passage of nociceptive information is relayed through the spinal cord dorsal horn, a critical area in sensory processing. The neuronal circuits in this region that underpin sensory perception must be clarified to better understand how dysfunction can lead to pathological pain. This study used an optogenetic approach to selectively activate neurons that contain the calcium-binding protein calretinin (CR). We show that CR+ interneurons form an interconnected network that can initiate and sustain enhanced excitatory signaling, and directly relays signals to lamina I projection neurons. In vivo photoactivation of CR+ interneurons resulted in a significant nocifensive behavior that was morphine sensitive and cause a conditioned place aversion. Furthermore, halorhodopsin-mediated inhibition of CR+ interneurons elevated sensory thresholds. These results suggest that neuronal circuits in the superficial dorsal horn that involve excitatory CR+ neurons are important for the generation and amplification of pain, and identify these interneurons as a future analgesic target.
Airbag associated fatal head injury: case report and review of the literature on airbag injuries
by
Nee, P A
,
Gradwell, E
,
Cunningham, K
in
Accidents, Traffic
,
Air bags
,
Air Bags - adverse effects
2000
Airbags have been shown to significantly reduce mortality and morbidity in motor vehicle crashes. However, the airbag, like the seat belt, produces its own range of injuries. With the increasing use of airbags in the UK, airbag associated injuries will be seen more often. These are usually minor, but in certain circumstances severe and fatal injuries result. Such injuries have been described before in the medical literature, but hitherto most reports have been from North America. This is the first case report from the UK of serious injury due to airbag deployment and describes the case of a driver who was fatally injured when her airbag deployed in a moderate impact frontal collision where such severe injury would not normally have been anticipated. The range of airbag associated injuries is described and predisposing factors such as lack of seat belt usage, short stature, and proximity to airbag housing are discussed. The particular dangers airbags pose to children are also discussed.
Journal Article