Mosquito midgut stem cell cellular defense response limits Plasmodium parasite infection.

A novel cellular response of midgut progenitors (stem cells and enteroblasts) to Plasmodium berghei infection was investigated in Anopheles stephensi. The presence of developing oocysts triggers proliferation of midgut progenitors that is modulated by the Jak/STAT pathway and is proportional to the number of oocysts on individual midguts. The percentage of parasites in direct contact with enteroblasts increases over time, as progenitors proliferate. Silencing components of key signaling pathways through RNA interference (RNAi) that enhance proliferation of progenitor cells significantly decreased oocyst numbers, while limiting proliferation of progenitors increased oocyst survival. Live imaging revealed that enteroblasts interact directly with oocysts and eliminate them. Midgut progenitors sense the presence of Plasmodium oocysts and mount a cellular defense response that involves extensive proliferation and tissue remodeling, followed by oocysts lysis and phagocytosis of parasite remnants by enteroblasts.

Mosquito midgut stem cell cellular defense response limits Plasmodium parasite infection.

A novel cellular response of midgut progenitors (stem cells and enteroblasts) to Plasmodium berghei infection was investigated in Anopheles stephensi. The presence of developing oocysts triggers proliferation of midgut progenitors that is modulated by the Jak/STAT pathway, and proportional to the number of oocysts on individual midguts. The percentage of parasites in direct contact with enteroblasts increases over time, as progenitors proliferate. Enhancing proliferation of progenitors significantly decreases oocyst numbers, while limiting proliferation increases oocyst survival. Live imaging revealed that enteroblasts interact directly with oocysts and eliminate them. Midgut progenitors sense the presence of Plasmodium oocysts and mount a cellular defense response that involves extensive proliferation and tissue remodeling, followed by oocysts lysis and phagocytosis of parasite remnants by enteroblasts.

Hypertonic saline versus fluid restriction: The pitfalls in managing acute hyponatremia in a patient with long-standing spinal cord injury.

Spinal cord injury-induced hyponatremia is an under-recognized entity, without a mention in the European hyponatremia guidelines. We present a case of a 56-year-old female quadraplegic patient with cervical cord injury, presenting with severe hyponatremia and tonic-clonic seizures. This case highlights the challenges in medical management; action mechanisms are further discussed.

Lipohypertrophy contributing to severe diabetic ketoacidosis in type 1 diabetes: An increasing problem in the context of the COVID-19 pandemic?

A 57-year-old man with type 1 diabetes was admitted with diabetic ketoacidosis during the COVID-19 pandemic. On examination, there was evidence of severe lipohypertrophy on his abdomen. Repeated injection of subcutaneous insulin into areas of lipohypertrophy was thought to have contributed to the development of ketoacidosis.

Colesevelam-induced hypoglycaemia in a patient with type 1 diabetes mellitus.

Colesevelam possesses antidiabetic properties, which could potentiate sulphonylurea or insulin-induced hypoglycemia; clinically significant hypoglycemia, as a side effect to bile acid sequestrants, may be under-recognized in clinical practice.

Lesson of the month: Acute pancreatitis due to hypertriglyceridaemia in a transgender woman: a complication of high-dose oral oestrogen therapy?

Acute pancreatitis (AP) is a medical emergency associated with significant morbidity and mortality. Hypertriglyceridaemia is a well-established but often neglected cause of AP, associated with delayed diagnosis and worse outcome than other more common causes of AP. Although oestrogen-induced hypertriglyceridaemia is known to be a rare cause of AP in females, it is much less well-recognised in biological males. We report the case of a 52-year-old transgender woman receiving high-dose oral oestrogen therapy who was admitted with abdominal pain and found to have AP caused by severe hypertriglyceridaemia. We describe the features underlying the management of AP caused by hypertriglyceridaemia and review the link between oral oestrogen, hypertriglyceridaemia and AP.Given the growth in transgender medicine leading to increasing use of therapeutic high-dose oestrogens in biological males for gender reassignment, it is important that clinicians are alert to the phenomenon of oestrogen-induced-hypertriglyceridaemia and its associated risk of AP.

The short-term impact of vitamin D-based hip fracture prevention in older adults in the United Kingdom.

PURPOSE: Vitamin D is a relatively inexpensive drug yet an important hormone in terms of calcium and bone homeostasis. Treatment with vitamin D is associated with reduced fracture risk particularly in an elderly population. Therefore, we assessed the budgetary impact of routine prescription of 800 IU daily colecalciferol on hip fracture among older adults in the United Kingdom. METHODS: Using meta-analysis findings for treatment effect and UK-estimates of incidence, we performed a health economic evaluation of treating the UK population aged 65 and over with 800 IU of vitamin D daily, assessing the impact upon hip fracture costs using incremental attributable costs and excess mortality for a range of age- gender-based treatment strategies. RESULTS: Using only a 1-year horizon, considering only reduction in hip fracture, prescribing colecalciferol 800 IU daily to all adults aged 65 and over, could reduce the number of incident hip fractures from 65,400 to 45,700, saving almost 1,700 associated deaths, whilst saving the UK taxpayer £22 million. CONCLUSIONS: As the UK government seeks to reduce public expenditure in all sectors, investment in prescribed prophylactic colecalciferol 800 IU therapy for adults aged 65 and over is likely to yield cost savings through reduction hip fracture alone in the first year.

Relationships between glucose, energy intake and dietary composition in obese adults with type 2 diabetes receiving the cannabinoid 1 (CB1) receptor antagonist, rimonabant.

BACKGROUND: Weight loss is often difficult to achieve in individuals with type 2 diabetes and anti-obesity drugs are often advocated to support dietary intervention. Despite the extensive use of centrally acting anti-obesity drugs, there is little evidence of how they affect dietary composition. We investigated changes in energy intake and dietary composition of macro- and micronutrients following therapy with the endocannabinoid receptor blocker, rimonabant. METHODS: 20 obese patients with type 2 diabetes were studied before and after 6 months dietary intervention with rimonabant. Dietary intervention was supervised by a diabetes dietician. Five-day food diaries were completed at baseline and at 6 months and dietary analysis was performed using computer software (Dietplan 6). RESULTS: After 6 months, (compared with baseline) there were reductions in weight (107 ± 21Kg versus 112 ± 21, p < 0.001, 4% body weight reduction), and improvements in HbA1c (7.4 ± 1.7 versus 8.0 ± 1.6%, p < 0.05) and HDL cholesterol. Intake of energy (1589 ± 384 versus 2225 ± 1109 kcal, p < 0.01), carbohydrate (199 ± 74 versus 273 ± 194 g, p < 0.05), protein (78 ± 23 versus 98 ± 36 g, p < 0.05), fats (55 ± 18 versus 84 ± 39 g, p < 0.01) and several micronutrients were reduced. However, relative macronutrient composition of the diet was unchanged. Improvement in blood glucose was strongly correlated with a reduction in carbohydrate intake (r = 0.76, p < 0.001). CONCLUSIONS: In obese patients with type 2 diabetes, rimonabant in combination with dietary intervention led to reduced intake of energy and most macronutrients. Despite this, macronutrient composition of the diet was unaltered. These dietary changes (especially carbohydrate restriction) were associated with weight loss and favourable metabolic effects.

Effects of substitution on 9-(3-bromo-4-fluorophenyl)-5,9-dihydro-3H,4H-2,6-dioxa-4- azacyclopenta[b]naphthalene-1,8-dione, a dihydropyridine ATP-sensitive potassium channel opener.

Structure-activity relationships were investigated on the tricyclic dihydropyridine (DHP) KATP openers 9-(3-bromo-4-fluorophenyl)-5,9-dihydro-3H,4H-2,6-dioxa-4-azacyclopenta[b]naphthalene-1,8-dione (6) and 10-(3-bromo-4-fluorophenyl)-9,10-dihydro-1H,8H-2,7-dioxa-9-azaanthracene-4,5-dione (65). Substitution off the core of the DHP, absolute stereochemistry, and aromatic substitution were evaluated for KATP channel activity using Ltk- cells stably transfected with the Kir6.2/SUR2B exon 17- splice variant and in an electrically stimulated pig bladder strip assay. A select group of compounds was evaluated for in vitro inhibition of spontaneous bladder contractions. Several compounds were found to have the unique characteristic of partial efficacy in both the cell-based and electrically stimulated bladder strip assays but full efficacy in inhibiting spontaneous bladder strip contractions. For compound 23b, this profile was mirrored in vivo where it was fully efficacious in inhibiting spontaneous myogenic bladder contractions but only partially able to reduce neurogenically mediated reflex bladder contractions.

Noninvasive assessment of preclinical atherosclerosis.

Initially considered as a semipermeable barrier separating lumen from vessel wall, the endothelium is now recognised as a complex endocrine organ responsible for a variety of physiological processes vital for vascular homeostasis. These include the regulation of vascular tone, luminal diameter, and blood flow; hemostasis and thrombolysis; platelet and leucocyte vessel-wall interactions; the regulation of vascular permeability; and tissue growth and remodelling. The endothelium modulates arterial stiffness, which precedes overt atherosclerosis and is an independent predictor of cardiovascular events. Unsurprisingly, dysfunction of the endothelium may be considered as an early and potentially reversible step in the process of atherogenesis and numerous methods have been developed to assess endothelial status and large artery stiffness. Methodology includes flow-mediated dilatation of the brachial artery, assessment of coronary flow reserve, carotid intima/media thickness, pulse wave analysis, pulse wave velocity, and plethysmography. This review outlines the various modalities, indications, and limitations of available methods to assess arterial dysfunction and vascular risk.

Hormone replacement therapy in hypopituitarism.

Hypopituitarism is a disease complex characterised by varying pituitary hormonal deficiencies. The causes and manifestations of hypopituitarism are diverse, the most common being the presence of or treatment of a pituitary adenoma. Pressure effects from the tumour itself on normal pituitary tissue, together with the effects of surgical resection, results in variable degrees of hypopituitarism. The latter precipitates end-organ failure leading to a variety of symptoms and signs, which are often nonspecific and vague. The broad aims of managing patients with hypopituitarism are to provide amelioration of the symptomatology associated with the condition, to avoid potentially acute life-threatening complications and to protect against long-term sequelae that may include osteoporosis and cardiovascular disease. This is achieved through lifelong therapeutic replacement of target hormonal deficiencies, such as corticosteroids or sex hormones, or replacement of the pituitary hormones themselves (i.e., growth hormone and vasopressin). Although the general principle of replacing missing hormones seems straightforward, in reality, existing hormonal therapeutic regimes often result in unphysiological replacement. Furthermore, there may be problems associated with their administration and routine monitoring. There is now little doubt that the hypopituitary state is associated with increased cardiovascular mortality. However, the precise underlying mechanisms responsible have not been fully elucidated, but probably include untreated growth hormone deficiency and/or unphysiological replacement of other target hormones. An effective strategy of tailoring hormonal replacement regimes to individual needs remains a challenge but is imperative if the increased morbidity and mortality associated with hypopituitarism is to be addressed.

Synthesis and structure-activity relationships of a novel series of tricyclic dihydropyridine-based KATP openers that potently inhibit bladder contractions in vitro.

Structure-activity relationships were investigated on a novel series of tricyclic dihydropyridine-containing K(ATP) openers. This diverse group of analogues, comprising a variety of heterocyclic rings fused to the dihydropyridine nucleus, was designed to determine the influence on activity of hydrogen-bond-donating and -accepting groups and their stereochemical disposition. Compounds were evaluated for K(ATP) activity in guinea pig bladder cells using a fluorescence-based membrane potential assay and in a pig bladder strip assay. The inhibition of spontaneous bladder contractions in vitro was also examined for a subset of compounds. All compounds studied showed greater potency to inhibit spontaneous bladder contractions relative to their potencies to inhibit contractions elicited by electrical stimulation.

Effects of GH on lipid peroxidation and neutrophil superoxide anion-generating capacity in hypopituitary adults with GH deficiency.

OBJECTIVES: Untreated growth hormone deficiency (GHD) is implicated in the increased cardiovascular risk associated with adult hypopituitarism. Oxidative stress, predisposing to lipid peroxidation, may be an important mediator of endothelial dysfunction, a pro-atherogenic state associated with adult GHD. DESIGN AND PATIENTS: In a randomized, double-blind, placebo-controlled study we investigated the effects of GH replacement on low-density lipoprotein (LDL) oxidation and neutrophil superoxide (O(-)(2)) generating capacity in 32 GHD adults (19 males, 13 females; age range 19-64 years) over 3 months. Thirty age- and sex-matched healthy controls were also studied. MEASUREMENTS: Lipid hydroperoxides (HPOs) in plasma were measured using the ferrous oxidation with xylenol orange (FOX) assay. The susceptibility of LDL to oxidation was assessed by the copper-catalysed lag phase of LDL oxidation. Neutrophil O(-)(2)- generating capacity was assessed by a lucigenin-based chemiluminescent assay of NADPH oxidase activity. Body composition was assessed using bioelectrical impedance analysis. RESULTS: Compared to controls, GHD subjects had higher LDL cholesterol (4.0 +/- 0.8 vs. 3.5 +/- 0.9 mmol/l, P < 0.01) and higher triglyceride concentrations (2.3 +/- 1.5 vs. 1.1 +/- 0.7 mmol/l, P < 0.001) but lower HDL cholesterol (1.1 +/- 0.3 mmol/l vs. 1.4 +/- 0.4 mmol/l, P < 0.01), lower levels of HPOs (0.72 +/- 0.35 vs. 0.92 +/- 0.20 microm, P < 0.01) and lower basal (2.5 +/- 1.5 vs. 4.5 +/- 2.3 mV/5 x 10(5) neutrophils, P < 0.01) and peak post-activation levels (23.2 +/- 11.1 vs. 34.4 +/- 15.6 mV/5 x 10(5) neutrophils, P < 0.01) of neutrophil O(-)(2)- generation. GH replacement resulted in an increase in HPOs from 0.70 +/- 0.39 to 0.86 +/- 0.19 microm (P < 0.05), although there was no change in the lag time of LDL oxidation. Neutrophil O(-)(2)- generating capacity was enhanced with a rise in basal O(-)(2)- generation from 2.8 +/- 1.4 to 5.4 +/- 4.6 mV/5 x 10(5) neutrophils (P < 0.05) and in peak post-activation O(-)(2)- generation from 21.9 +/- 9.5 to 35.8 +/- 21.7 mV/5 x 10(5) neutrophils (P < 0.05). LDL cholesterol was reduced from 4.1 +/- 0.8 mmol/l to 3.5 +/- 0.8 mmol/l (P < 0.01). No significant changes in measured parameters occurred in the placebo group. CONCLUSIONS: Adult GHD is associated with reduced lipid peroxidation and impaired neutrophil O(-)(2)- generating capacity, both of which are reversible with GH replacement. Our data suggest that: (i) that oxidative stress is not a major feature of the pro-atherogenic state in hypopituitary adults with GHD and (ii) a role for GH in modulating neutrophil function and leucocyte-lipoprotein interactions.

Effects of GH replacement on endothelial function and large-artery stiffness in GH-deficient adults: a randomized, double-blind, placebo-controlled study.

OBJECTIVES: Hypopituitary adults with growth hormone deficiency (GHD) have an increased cardiovascular mortality, although the mechanisms remain unclear. Endothelial dysfunction, characterized by reduced nitric oxide (NO) bioavailability, is a key early event in atherogenesis and is associated with increased vascular smooth muscle tone and arterial stiffening. DESIGN AND PATIENTS: In a randomized, double-blind, placebo-controlled study, we investigated the effects of GH replacement on endothelial function and large-artery stiffness in 32 GHD adults (19 males, 13 females) (age range 19-64 years) over a 6-month period. Thirty-two age- and sex-matched healthy controls were also studied. MEASUREMENTS: Endothelial function was assessed using ultrasonic wall tracking to measure flow-mediated dilatation (FMD) of the brachial artery. Large artery stiffness was assessed by pulse wave analysis of the radial artery pressure waveform, allowing determination of the corresponding central arterial pressure waveform and derivation of the augmentation index. Fasting lipid profiles, glucose and insulin were also measured. RESULTS: At baseline, FMD (mean +/- SD) was impaired in GH-deficient subjects vs. controls (3.4 +/- 2.3 vs. 5.7 +/- 2.0%, P < 0.0001), although endothelium-independent dilatation was similar. The augmentation index was higher in GH-deficient subjects vs. controls (23 +/- 12 vs. 14 +/- 14%, P < 0.01). GH-deficient subjects had higher LDL cholesterol (4.1 +/- 0.8 vs. 3.5 +/- 0.8 mmol/l, P < 0.01) and lower HDL cholesterol (1.1 +/- 0.3 vs. 1.4 +/- 0.4 mmol/l, P < 0.01). In GH-deficient subjects, there were inverse correlations between LDL cholesterol and FMD (r = -0.40, P < 0.05) and between FMD and the augmentation index (r = - 0.58, P < 0.01). Regression analysis identified FMD as an independent predictor of the augmentation index (P < 0.0001). In comparison with baseline, GH replacement resulted in an increase in FMD (5.0 +/- 2.6 vs. 2.8 +/- 1.9%, P < 0.01). There were decreases in central aortic systolic pressure (117 +/- 15 vs. 123 +/- 17 mmHg, P < 0.01), diastolic pressure (82 +/- 10 vs. 86 +/- 8 mmHg, P < 0.01) and the augmentation index (22 +/- 8% vs. 26 +/- 10%, P < 0.05) despite unchanged brachial pressure indices. LDL cholesterol also decreased (3.5 +/- 0.8 vs. 4.2 +/- 0.8 mmol/l, P < 0.01). There were no significant changes in the placebo group. CONCLUSIONS: Adult GHD is associated with endothelial dysfunction and increased large-artery stiffness. An improvement in endothelial function and a reduction in arterial stiffness following GH replacement suggests an important therapeutic role for GH in reducing cardiovascular risk associated with adult GHD.