Anaesthetic considerations for impacted fetal head at caesarean delivery: a focused review.

BACKGROUND: Impacted fetal head occurs when the fetal head is deeply engaged within the maternal pelvis and difficult to deliver during caesarean delivery. In order to deliver the fetal head, additional surgical manoeuvres and/or pharmacological tocolysis are needed. The aim of this focused review is to outline the incidence, risk factors, management and complications of this obstetric emergency from the perspective of the anaesthetist. METHODS: Databases were searched for free text headings and subject headings associated with different permutations of terms related to impacted fetal head and caesarean delivery. RESULTS: Impacted fetal head has been estimated to occur in 1.5 % of elective caesarean deliveries and 2.9-18.4% of all emergency caesarean deliveries at any cervical dilatation. Risk factors include advanced cervical dilatation, labour augmentation with oxytocin, prolonged second stage of labour, fetal malposition and junior grade of operating obstetrician. If impacted fetal head occurs, the anaesthetist in conjunction with the multidisciplinary team should consider decreasing the height of the operating table, providing a step for the obstetrician to stand on, placing the patient in the head down position, providing pharmacological tocolysis with glyceryl trinitrate (or nitroglycerin), beta-2 adrenoreceptor agonists or volatile anaesthetic agents, and managing complications such as postpartum haemorrhage. CONCLUSION: Impacted fetal head is an obstetric emergency that the anaesthetist should be familiar with and has a vital role in managing. We propose an algorithm for management that may serve as a clinical decision aid.

Effects of Local Vasodilators and the Autonomic Nervous System on Microcirculation and Mitochondrial Function in Septic Rats.

Systemic vasodilating agents like nitroglycerin (NG) or iloprost (Ilo) show beneficial effects on intestinal microcirculation during sepsis, which could be attenuated by activation of the sympathetic nervous system or systemic side effects of vasodilating agents. This exploratory study aimed to investigate the effects of topically administered vasodilators and the parasympathetic drug carbachol on colonic microcirculatory oxygenation (µHbO2), blood flow (µFlow) and mitochondrial respiration. A total of 120 male Wistar rats were randomly assigned to twelve groups and underwent either colon ascendens stent peritonitis (CASP) or sham surgery. After 24 h, animals received the following therapeutic regimes: (1) balanced full electrolyte solution, (2) carbachol, (3) NG, (4) Ilo, (5) NG + carbachol, and (6) Ilo + carbachol. Mitochondrial respiration was measured in colon homogenates by respirometry. In sham animals, NG (-13.1%*) and Ilo (-10.5%*) led to a decrease in µHbO2. Additional application of carbachol abolished this effect (NG + carbachol: -4.0%, non-significant; Ilo + carbachol: -1.4%, non-significant). In sepsis, carbachol reduced µHbO2 when applied alone (-10.5%*) or in combination with NG (-17.6%*). Thus, the direction and degree of this effect depend on the initial pathophysiologic condition.

Impact of nitroglycerin on machine-learning fractional flow reserve in coronary computed tomography (CT)-angiography.

Background: Nitroglycerin administration prior to examination improves stenosis assessment of coronary computed tomography (CT) angiography (CCTA). However, whether nitroglycerin influences CT-derived fractional flow reserve (FFR, CT-FFR) evaluation remains unclear. This study aimed to investigate the effect of nitroglycerin on diagnostic performance of CT-FFR. Methods: In this single-center retrospective study, 107 consecutive patients suspected of coronary artery disease (CAD) with nitroglycerin administration prior to CCTA in 2019 were matched to 107 patients without nitroglycerin in 2016 from Fuwai Hospital. All patients underwent CCTA and invasive FFR in a month. Vessel-based and patient-based accuracy and diagnostic performance of CT-FFR were compared between the two groups, as well as image quality, coronary artery diameter and evaluability. Quantitative variables were compared by Kruskal-Wallis H test. Categorical variables and rates were compared by χ2 test or Fisher exact test. Results: A total of 214 patients (56.1±8.9 years, 155 male) with 237 target lesion vessels were analyzed, including 120 vessels in nitroglycerin and 117 vessels in non-nitroglycerin group. Per-vessel based accuracy of CT-FFR was higher in nitroglycerin group {80.0% [95% confidence interval (CI): 71.7-86.7%] vs. 68.4% (59.1-76.7%), P=0.041}. On a per-patient basis, nitroglycerin administration improved the accuracy [83.2% (74.7-89.7%) vs. 68.2% (58.5-76.9%), P=0.01], specificity [82.7% (69.7-91.8%) vs. 61.9% (48.8-73.9%), P=0.01], positive predictive value (PPV) [83.6% (73.6-90.4%) vs. 58.6% (50.0-66.9%), P=0.004], and area under the curve (AUC) [0.83 (0.75-0.89) vs. 0.71 (0.61-0.79), P=0.03] of CT-FFR. Vessel diameters (left main arteries: 4.3 vs. 3.8 mm, P<0.001; left anterior descending arteries: 3.1 vs. 2.9 mm, P=0.001; left circumflex arteries: 2.9 vs. 2.7 mm, P=0.01; right coronary arteries: 3.7 vs. 3.4 mm, P=0.001) and number of evaluable coronary arteries (11.0 vs. 8.0, P<0.001) were larger in nitroglycerin group. Conclusions: Nitroglycerin administration prior to CCTA has positive effects on diagnostic performance of CT-FFR.

The effect of nitroglycerin treatment on cerebral ischaemia: A systematic review and meta-analysis of animal studies.

BACKGROUND: Nitroglycerin has been of considerable interest as a treatment for ischaemic stroke. Recent clinical trials with nitroglycerin transdermal patches during the acute phase of stroke failed to improve functional outcomes. Systematic review and meta-analysis of the effectiveness of nitroglycerin in preclinical models of ischaemic stroke has not previously been reported, despite several clinical trials. OBJECTIVE: To conduct a systematic review and meta-analysis of preclinical evidence regarding the effect of nitroglycerin on infarct volume in animal models of ischaemic stroke. SUMMARY OF REVIEW: The protocol was registered in PROSPERO (CRD42023432644). Our search identified 238 publications. Three publications met inclusion criteria (including 10 comparisons of infarct size). Study quality was modest (median 6 out of 9), with no evidence of publication bias. Nitroglycerin did not significantly reduce infarct volume (NMD point estimate 20.2 % reduction, 95 % CI -1.52-52.7 %, p = 0.068). Subgroup analysis suggested greater efficacy of nitroglycerin with direct intracarotid administration to the ischaemic territory at the time of reperfusion. CONCLUSIONS: A small number of studies (three) were included in this review. Overall, nitroglycerin did not reduce infarct volume in experimental stroke models. However, nitroglycerin may be of benefit when administered directly into the ischaemic territory. Given nitroglycerin's short half-life, we propose this route may minimise harmful reduction of cerebral perfusion pressure resulting from hypotension following systemic administration.

[Efficient patient preparation in computed tomography coronary angiography]. / Effiziente Patientenvorbereitung in der Computertomographie-Koronarangiographie.

BACKGROUND: In the coming years, a significant increase in the number of computed tomography coronary angiographies (CCTA) is expected, leading to an additional burden on existing structures. OBJECTIVES: Discussion of effective processes and patient preparation in the context of high-volume CCTA. MATERIALS AND METHODS: The relevance of patient education and optimized workflows in clinical practice, including pharmacological heart rate control and vasodilation. RESULTS: To conduct resource-efficient and effective patient examinations, comprehensive and clear patient education is crucial. This can be provided to the patient during scheduling or delivered digitally, so that the patient arrives with a thorough understanding of the examination process. In addition, targeted optimization of workflows tailored to CCTA is important. For high image quality, the administration of ß­blockers is necessary in most cases. This can be done intravenously to save time. The administration of nitrates immediately before the examination is recommended by current guidelines for all patients without contraindications and is ideally applied sublingually shortly before the examination. CONCLUSION: The anticipated increase in CCTA will significantly strain existing structures not only in terms of reporting. Especially standardized and structured workflows pre- and periprocedurally are essential for handling a high number of examinations, while maintaining sufficient image quality in clinical practice.

The Effect of Nitroglycerin Treatment Initiation Time on Survival in Partial Flap Necrosis: An Experimental Study.

Background: Nitroglycerin is suggested to improve flap survival based on promising results; however, there are no data on the effectiveness of treatment initiation time. This study aimed to compare the effect of various nitroglycerin treatment initiation times on partial flap survival. Materials and Methods: The study included 50 Sprague-Dawley rats. Modified McFarlane flaps were elevated on the dorsum of each rat. Group A received placebo treatment. Groups B, C, D, and E received topical nitroglycerin 2% starting 1 day before surgery, on the day of surgery, postoperative d 2, and postoperative d 4, respectively. After 7 days, the flap survival rates were calculated. Afterward, the severity and extent of inflammation and ischemia, and the severity of edema were evaluated histologically. Results: The flap survival rate was highest in group B, followed by groups C, D, E, and A. The difference between groups B and C was not significant, whereas the difference between group B and groups A, D, and E was. In addition, the difference between groups A, D, and E was not significant. Histological analysis showed that inflammation was less severe in groups B and C than in groups A, D, and E. Ischemia was the most severe in groups A and D and was the least severe in group C. Conclusion: Topical nitroglycerin treatment increases flap survival when initiated before or on the day of surgery, but has no benefit when initiated on postsurgery d 2 or 4. Preoperative initiation of nitroglycerin treatment positively affects flap survival.

Contexte: L'utilisation de la nitroglycérine a été proposée pour améliorer la survie d'un lambeau à partir de résultats prometteurs. Il n'y a cependant aucune donnée sur l'efficacité du délai d'instauration du traitement. Cette étude a visé à comparer l'effet de différents moments d'instauration du traitement avec la nitroglycérine sur la survie d'un lambeau partiel. Matériels et méthodes: L'étude a inclus 50 rats Sprague-Dawley. Des lambeaux modifiés de McFarlane ont été surélevés sur le dos de chaque rat. Le groupe A a reçu un placebo, tandis que les groupes B, C, D et E ont reçu de la nitroglycérine topique à 2% en commençant, respectivement, la veille de la chirurgie, le jour de la chirurgie, 2 jours et 4 jours postopératoires. Les taux de survie du volet ont été calculés après 7 jours. Ensuite, la sévérité et l'étendue de l'inflammation et de l'ischémie ainsi que la sévérité de l'œdème ont été évaluées histologiquement. Résultats: Le taux de survie des volets a été le plus élevé dans le groupe B, suivi des groupes C, D, E et A. La différence entre les groupes B et C n'était pas significative, tandis que la différence entre le groupe B et les groupes A, D et E l'était. En outre, la différence entre les groupes A, et E n'était pas significative. L'analyse histologique a montré que l'inflammation était moins sévère dans les groupes B et C que dans les groupes A, D et E. L'ischémie a été la plus importante dans les groupes A et D et la moins importante dans le groupe C. Conclusion: Le traitement topique avec la nitroglycérine augmente la survie d'un lambeau quand il est commencé le jour de la chirurgie ou avant, mais il n'apporte pas d'avantage s'il est instauré au 2e ou au 4e jour postopératoire. L'instauration d'un traitement par la nitroglycérine en préopératoire a un effet positif sur la survie des lambeaux.

Computed tomography angiography assessment of Adamkiewicz artery with sublingual nitroglycerin administration.

PURPOSE: Identification of the Adamkiewicz artery before aortic surgery is important for preventing postoperative complications due to spinal cord ischemia. The Adamkiewicz artery is difficult to identify due to its small diameter. Nitroglycerin has a vasodilatory effect and is used clinically to improve visualization of blood vessels on coronary computed tomography (CT) angiography. We investigated whether the vasodilatory effect of nitroglycerin could improve the ability to visualize the Adamkiewicz artery. METHODS: We extracted 33 cases wherein contrast-enhanced CT images were taken before and after aortic aneurysm surgery. Nitroglycerin was administered for coronary artery evaluation on the preoperative CT. However, no nitroglycerin was administered before the postoperative CT. Aortic contrast-to-noise ratio, CT value, image noise, and diameter of the Adamkiewicz artery and anterior spinal artery were measured. The depiction of the Adamkiewicz artery was graded into four grades and evaluated. These measurements were performed by two independent reviewers. RESULTS: In nitroglycerin-administered cases, the contrast-to-noise ratio and CT values were significantly higher (P < 0.001, P < 0.001, respectively); the Adamkiewicz artery and anterior spinal artery diameters were dilated (P = 0.005, P = 0.001, respectively). The Adamkiewicz artery score also improved significantly (P < 0.001). No significant difference was found in image noise. CONCLUSION: Nitroglycerin contributed to improving the Adamkiewicz artery's visualization.

The use of injectable subcutaneous terbutaline and topical nitroglycerin ointment in the treatment of peripheral vasopressor extravasation in 3 dogs.

OBJECTIVE: To describe the clinical course and treatment of 3 dogs with peripheral vasopressor extravasation. CASE SERIES SUMMARY: Although vasopressor extravasation (VE) is a well-documented complication in human medicine, literature describing VE and its management in veterinary patients is sparse. VE increases patient morbidity by causing local tissue injury and necrosis. The gold standard treatment for VE, phentolamine, has been periodically limited in supply in human medicine and is not consistently available for use in veterinary medicine. An alternative protocol proposed for use in people with VE combines topical nitroglycerin application with subcutaneous terbutaline infiltration. In this report, a treatment protocol utilizing these therapies was used to treat 3 dogs with VE and secondary tissue injury. NEW OR UNIQUE INFORMATION PROVIDED: This report describes 3 cases of VE-induced tissue injury in dogs. In addition, this report describes the use of perivascular terbutaline infiltration and topical nitroglycerin application as therapeutic management for VE in dogs.

Coronary and Systemic Vasodilator Responsiveness of Patients Receiving Conventional Intermittent or Nocturnal Hemodialysis.

BACKGROUND: Nocturnal hemodialysis (nHD) restores the attenuated brachial artery vasodilator responsiveness of patients receiving conventional intermittent hemodialysis (iHD). Its impact on coronary vasodilatation is unknown. METHODS: We evaluated 25 patients on hemodialysis who fulfilled transplant criteria: 15 on iHD (4-hour sessions, 3 d/wk) and 10 on nHD (≈40 h/wk over 8-10-hour sessions) plus 6 control participants. Following diagnostic angiography, left anterior descending (LAD) coronary flow reserve and mean luminal diameter were quantified at baseline and during sequential intracoronary administration of adenosine (infusion and bolus), nitroglycerin (bolus), acetylcholine (infusion), acetylcholine coinfused with vitamin C, and, finally, sublingual nitroglycerin. RESULTS: Coronary flow reserve in those receiving nHD was augmented relative to iHD (3.28±0.26 versus 2.17±0.12 [mean±SEM]; P<0.03) but attenuated, relative to controls (4.80±0.63; P=0.011). Luminal dilatations induced by intracoronary adenosine and nitroglycerin were similar in nHD and controls but blunted in the iHD cohort (P<0.05 versus both). ACh elicited vasodilatation in controls but constriction in both dialysis groups (both P<0.05, versus control); vitamin C coinfusion had no effect. Sublingual nitroglycerin increased mid-left anterior descending diameter and reduced mean arterial pressure in controls (+15.2±2.68%; -16.00±1.60%) and in nHD recipients (+14.78±5.46%; -15.82±1.32%); iHD responses were markedly attenuated (+1.9±0.86%; -5.89±1.41%; P<0.05, all comparisons). CONCLUSIONS: Coronary and systemic vasodilator responsiveness to both adenosine and nitroglycerin is augmented in patients receiving nHD relative to those receiving iHD, whereas vasoconstrictor responsiveness to acetylcholine does not differ. By improving coronary conduit and microvascular function, nHD may reduce the cardiovascular risk of patients on dialysis.

Effects of Metformin on CIMT and FMD in PCOS patients: a systematic review and meta-analysis.

BACKGROUND: This study aims to analyze the efficacy of metformin on carotid intima media thickness (CIMT) and flow-mediated dilation (FMD) for patients with polycystic ovary syndrome (PCOS). METHODS: A literature search of PubMed, Embase, and the Cochrane Library from inception to December 2023 was conducted. Then, after studies selection and data extraction, the mean difference (MD) with a 95% confidence interval (CI) was used to evaluate metformin efficacy in CIMT and FMD for PCOS patients. Heterogeneity was investigated through subgroup and sensitivity analysis. The protocol of our study has been registered in PROSPERO (CRD42024497239). RESULTS: A total of 12 studies with 248 patients were included. CIMT was lower in the endpoint group (after metformin) compared with the baseline group (before metformin) (MD = -0.11, 95% CI = -0.21 to -0.01, p = 0.04). FMD was higher in the endpoint group compared with the baseline group (MD = 3.25, 95% CI = 1.85 to 4.66, p < 0.01). No statistically significant difference was observed in nitroglycerin-mediated dilation (NMD) between the two groups (MD = 0.65, p = 0.51). Subgroup analysis showed that a relatively lower MD of CIMT in PCOS patients from Europe in the endpoint group compared with the baseline group (MD = -0.09, 95% CI = -0.14 to -0.04, p < 0.001). However, the MD in CIMT was not significantly different between the endpoint group and baseline group in PCOS patients from Asia (p = 0.270). CONCLUSION: Metformin may have a beneficial effect on CIMT and FMD, but not on NMD, suggesting that metformin may help reduce cardiovascular events in PCOS patients. Notably, the clinical efficacy of metformin can be influenced by regional differences and study types.

Effect of membrane properties on the odor emanating from training aids for explosive-detecting canines.

Canines are widely used for real-time detection of explosives and have proven to be on par with instrumental methods. Canines are thought to rely largely upon detection of volatile chemical constituents of the explosives, though not necessarily the explosive itself. Hence, it is crucial to understand the odor available to them as generated by training aids. Previous studies have established that the Training Aid Delivery Device (TADD) developed by SciK9 is a reliable training aid that reduces cross-contamination and doubles as a storage device. A TADD comprises a standardized container, a synthetic membrane, a membrane holder, and a lid. In the work presented, activated charcoal strips were placed above and below the TADD membrane to determine the relative amounts of volatiles emitted by dynamite (i.e., ethylene glycol dinitrate (EGDN) and trinitroglycerin (NG)). The strips were eluted and the extracts tested using gas chromatography-mass spectrometry in negative ion chemical ionization mode. A series of t-tests at 95% confidence level were performed to determine any differences in vapor composition above and below the membranes. Nine synthetic membranes and six glass fiber membranes were tested in this study. It was expected that the relative concentration of volatiles would remain the same on both sides of the membrane; however, selective removal of nitroglycerin by some membranes was observed. Synthetic membranes with larger pore sizes showed no alteration in the vapor composition. Both synthetic and glass fiber membranes did not show a significant change in relative concentration of the other volatile compound in dynamite, i.e., EGDN. Out of all the membranes tested, three synthetic membranes and four glass fiber membranes showed selective alteration in odor availability of nitroglycerin in dynamite. For training purposes, membranes that do not alter the vapor composition should be used in the training aid.

Nadir blood pressure responses to longer consecutive cardiac cycle sequences absent of sympathetic bursts are associated with popliteal endothelial-dependent dilation.

PURPOSE: The nadir pressure responses to cardiac cycles absent of muscle sympathetic nerve activity (MSNA) bursts (or non-bursts) are typically reported in studies quantifying sympathetic transduction, but the information gained by studying non-bursts is unclear. We tested the hypothesis that longer sequences of non-bursts (≥8 cardiac cycles) would be associated with a greater nadir diastolic blood pressure (DBP) and that better popliteal artery function would be associated with an augmented reduction in DBP. METHODS: Resting beat-by-beat DBP (via finger photoplethysmography) and common peroneal nerve MSNA (via microneurography) were recorded in 39 healthy, adults (age 23.4 ± 5.3 years; 19 females). For each cardiac cycle absent of MSNA bursts, the mean nadir DBP (ΔDBP) during the 12 cardiac cycles following were determined, and separate analyses were conducted for ≥8 or < 8 cardiac cycle sequences. Popliteal artery endothelial-dependent (via flow-mediated dilation; FMD) and endothelial-independent vasodilation (via nitroglycerin-mediated dilation; NMD) were determined. RESULTS: The nadir DBP responses to sequences ≥8 cardiac cycles were larger (-1.40 ± 1.27 mmHg) than sequences <8 (-0.38 ± 0.46 mmHg; p < 0.001). In adjusting for sex and burst frequency (14 ± 8 bursts/min), larger absolute or relative FMD (p < 0.01), but not NMD (p > 0.53) was associated with an augmented nadir DBP. This overall DBP-FMD relationship was similar in sequences ≥8 (p = 0.04-0.05), but not <8 (p > 0.72). CONCLUSION: The DBP responses to non-bursts, particularly longer sequences, were inversely associated with popliteal endothelial function, but not vascular smooth muscle sensitivity. This study provides insight into the information gained by quantifying the DBP responses to cardiac cycles absent of MSNA.

Fenofibrate ameliorates nitroglycerin-induced migraine in rats: Role of CGRP/p-CREB/P2X3 and NGF/PKC/ASIC3 signaling pathways.

Migraine, a debilitating neurological condition, significantly affects patients' quality of life. Fenofibrate, a peroxisome proliferator-activated receptor alpha (PPAR-α) agonist approved for managing dyslipidemia, has shown promise in treating neurological disorders. Therefore, this study aims to investigate the protective effects of fenofibrate against nitroglycerin (NTG)-induced chronic migraine in rats. Migraine was induced in rats by administering five intermittent doses of NTG (10 mg/kg, i. p.) on days 1, 3, 5, 7, and 9. Rats were treated with either topiramate (80 mg/kg/day, p. o.), a standard drug, or fenofibrate (100 mg/kg/day, p. o.) from day 1-10. Fenofibrate significantly improved mechanical and thermal hypersensitivity, photophobia, and head grooming compared to topiramate. These effects were associated with reduced serum levels of nitric oxide (NO), calcitonin gene-related peptide (CGRP), and pituitary adenylate cyclase-activating polypeptide (PACAP). Furthermore, fenofibrate down-regulated c-Fos expression in the medulla and medullary pro-inflammatory cytokine contents. Additionally, fenofibrate attenuated NTG-induced histopathological changes in the trigeminal ganglia and trigeminal nucleus caudalis. These effects were associated with the inhibition of CGRP/p-CREB/purinergic 2X receptor 3 (P2X3) and nerve growth factor (NGF)/protein kinase C (PKC)/acid-sensing ion channel 3 (ASIC3) signaling pathways. This study demonstrates that fenofibrate attenuated NTG-induced migraine-like signs in rats. These effects were partially mediated through the inhibition of CGRP/p-CREB/P2X3 and NGF/PKC/ASIC3 signaling pathways. The present study supports the idea that fenofibrate could be an effective candidate for treating migraine headache without significant adverse effects. Future studies should explore its clinical applicability.

Endovascular Management of Acute Lower Limb Ischemia Linked to Cocaine Abuse: A Case Report.

Cocaine abuse is a public health concern with well-documented cardiovascular complications. However, acute limb ischemia remains a rare and underreported consequence. We present a case of a 36-year-old man with acute right lower limb ischemia following heavy cocaine use, successfully managed with systemic heparin and intra-arterial nitroglycerin. The case highlights considering cocaine as a potential cause of acute limb ischemia and the efficacy of endovascular therapy. Further case reports with this diagnosis and their management are crucial for establishing the best strategies and improving outcomes in these scenarios.

Parabrachial Calca neurons drive nociplasticity.

Pain that persists beyond the time required for tissue healing and pain that arises in the absence of tissue injury, collectively referred to as nociplastic pain, are poorly understood phenomena mediated by plasticity within the central nervous system. The parabrachial nucleus (PBN) is a hub that relays aversive sensory information and appears to play a role in nociplasticity. Here, by preventing PBN Calca neurons from releasing neurotransmitters, we demonstrate that activation of Calca neurons is necessary for the manifestation and maintenance of chronic pain. Additionally, by directly stimulating Calca neurons, we demonstrate that Calca neuron activity is sufficient to drive nociplasticity. Aversive stimuli of multiple sensory modalities, such as exposure to nitroglycerin, cisplatin, or lithium chloride, can drive nociplasticity in a Calca-neuron-dependent manner. Aversive events drive nociplasticity in Calca neurons in the form of increased activity and excitability; however, neuroplasticity also appears to occur in downstream circuitry.

Models of Trigeminal Activation: Is There an Animal Model of Migraine?

Migraine, recognized as a severe headache disorder, is widely prevalent, significantly impacting the quality of life for those affected. This article aims to provide a comprehensive review of the application of animal model technologies in unraveling the pathomechanism of migraine and developing more effective therapies. It introduces a variety of animal experimental models used in migraine research, emphasizing their versatility and importance in simulating various aspects of the condition. It details the benefits arising from the utilization of these models, emphasizing their role in elucidating pain mechanisms, clarifying trigeminal activation, as well as replicating migraine symptoms and histological changes. In addition, the article consciously acknowledges the inherent limitations and challenges associated with the application of animal experimental models. Recognizing these constraints is a fundamental step toward fine-tuning and optimizing the models for a more accurate reflection of and translatability to the human environment. Overall, a detailed and comprehensive understanding of migraine animal models is crucial for navigating the complexity of the disease. These findings not only provide a deeper insight into the multifaceted nature of migraine but also serve as a foundation for developing effective therapeutic strategies that specifically address the unique challenges arising from migraine pathology.

Differences in Neuropathology between Nitroglycerin-Induced Mouse Models of Episodic and Chronic Migraine.

Multiple animal models of migraine have been used to develop new therapies. Understanding the transition from episodic (EM) to chronic migraine (CM) is crucial. We established models mimicking EM and CM pain and assessed neuropathological differences. EM and CM models were induced with single NTG or multiple injections over 9 days. Mechanical hypersensitivity was assessed. Immunofluorescence utilized c-Fos, NeuN, and Iba1. Proinflammatory and anti-inflammatory markers were analyzed. Neuropeptides (CGRP, VIP, PACAP, and substance P) were assessed. Mechanical thresholds were similar. Notable neuropathological distinctions were observed in Sp5C and ACC. ACC showed increased c-Fos and NeuN expression in CM (p < 0.001) and unchanged in EM. Sp5C had higher c-Fos and NeuN expression in EM (p < 0.001). Iba1 was upregulated in Sp5C of EM and ACC of CM (p < 0.001). Proinflammatory markers were strongly expressed in Sp5C of EM and ACC of CM. CGRP expression was elevated in both regions and was higher in CM. VIP exhibited higher levels in the Sp5C of EM and ACC of CM, whereas PACAP and substance P were expressed in the Sp5C in both models. Despite similar thresholds, distinctive neuropathological differences in Sp5C and ACC between EM and CM models suggest a role in the EM to CM transformation.

Comparison of the efficacy of nifedipine with ritodrine, nitroglycerine and magnesium sulfate for the management of preterm labor: a systematic review and meta-analysis.

BACKGROUND: Some studies have compared the efficacy of nifedipine with that of other tocolytic drugs in the treatment of preterm labor, but the reported results are conflicting. OBJECTIVE: To compare the efficacy of nifedipine with that of ritodrine, nitroglycerine and magnesium sulfate for the management of preterm labor. METHODS: In this systematic review and meta-analysis, PubMed/MEDLINE, Scopus, Clarivate Analytics Web of Science, and Google Scholar were searched until April 3,2024 using predefined keywords. Randomized controlled trials (RCTs) and clinical trials that compared the efficacy of nifedipine with that of ritodrine, nitroglycerine and magnesium sulfate for the management of preterm labor were included. Two authors independently reviewed the articles, assessed their quality and extracted the data. The quality of the included RCTs based on the Cochrane Risk of Bias Tool 1 for clinical trial studies. The risk difference (RD) with the associated 95% confidence interval (CI) was calculated. A forest plot diagram was used to show the comparative point estimates of nifedipine and other tocolytic drugs on the prevention of preterm labor and their associated 95% confidence intervals based on the duration of pregnancy prolongation. Study heterogeneity was evaluated by the I2 index, and publication bias was evaluated by Egger's test. RESULTS: Forty studies enrolling 4336 women were included. According to our meta-analysis, there was a significant difference in the prolongation of preterm labor within the first 48 h between the nifedipine group and the nitroglycerine group (RD, -0.04; 95% CI, -0.08 to -0.00; I2: 32.3%). Additionally, there were significant differences between nifedipine and ritodrine (RD, 0.11; 95% CI, 0.02 to 0.21; I2, 51.2%) for more than one week RD, 0.10; 95% CI, 0.03 to 0.19; I2, 33.2%) and for 34 weeks and more. The difference between nifedipine and magnesium sulfate was not significant in any of the four time points. CONCLUSIONS: Considering the superiority of nifedipine over ritodrine and nitroglycerine and its similar efficacy to magnesium sulfate for tocolysis, it seems that the side effects of these options determine the first drug line.