A differential-targeting core-shell microneedle patch with coordinated and prolonged release of mangiferin and MSC-derived exosomes for scarless skin regeneration

Microneedles for skin regeneration are conventionally restricted by uncontrollable multi-drug release, limited types of drugs, and poor wound adhesion. Here, a novel core-shell microneedle patch is developed for scarless skin repair, where the shell is composed of hydrophilic gelatin methacryloyl (GelMA) loaded with mangiferin, an anti-inflammatory small molecule, and the core is composed of hydrophobic poly (lactide-co-propylene glycol-co-lactide) dimethacrylates (PGLADMA) loaded with bioactive macromolecule and human mesenchymal stromal cell (hMSC)-derived exosomes. This material choice provides several benefits: the GelMA shell provides a swelling interface for tissue interlocking and rapid release of mangiferin at an early wound healing stage for anti-inflammation, whereas the PGLADMA core offers long-term encapsulation and release of exosomes (30% release in 3 weeks), promoting sustained angiogenesis and anti-inflammation. Our results demonstrate that the core-shell microneedle possesses anti-inflammatory properties and can induce angiogenesis both in vitro in terms of macrophage polarization and tube formation of human umbilical vein endothelial cells (HUVECs), and in vivo in terms of anti-inflammation, re-epithelization, and vessel formation. Importantly, we also observe reduced scar formation in vivo. Altogether, the degradation dynamics of our hydrophilic/hydrophobic materials enable the design of a core-shell microneedle for differential and prolonged release, promoting scarless skin regeneration, with potential for other therapies of long-term exosome release.

Going below and beyond the surface: Microneedle structure, materials, drugs, fabrication, and applications for wound healing and tissue regeneration

Microneedle, as a novel drug delivery system, has attracted widespread attention due to its non-invasiveness, painless and simple administration, controllable drug delivery, and diverse cargo loading capacity. Although microneedles are initially designed to penetrate stratum corneum of skin for transdermal drug delivery, they, recently, have been used to promote wound healing and regeneration of diverse tissues and organs and the results are promising. Despite there are reviews about microneedles, few of them focus on wound healing and tissue regeneration. Here, we review the recent advances of microneedles in this field. We first give an overview of microneedle system in terms of its potential cargos (e.g., small molecules, macromolecules, nucleic acids, nanoparticles, extracellular vesicle, cells), structural designs (e.g., multidrug structures, adhesive structures), material selection, and drug release mechanisms. Then we briefly summarize different microneedle fabrication methods, including their advantages and limitations. We finally summarize the recent progress of microneedle-assisted wound healing and tissue regeneration (e.g., skin, cardiac, bone, tendon, ocular, vascular, oral, hair, spinal cord, and uterine tissues). We expect that our article would serve as a guideline for readers to design their microneedle systems according to different applications, including material selection, drug selection, and structure design, for achieving better healing and regeneration efficacy.

Review of ultrasonography of malignant neck nodes: greyscale, Doppler, contrast enhancement and elastography

Assessment of neck lymph nodes is essential in patients with head and neck cancers for predicting the patient’s prognosis and selecting the appropriate treatment. Ultrasonography is a useful imaging tool in the assessment of neck lymph nodes. Greyscale ultrasonography assesses the size, distribution, and internal architecture of lymph nodes. Doppler ultrasonography evaluates the intranodal vascular pattern and resistance of lymph nodes. Contrast-enhanced ultrasonography provides information on lymph node parenchymal perfusion. Elastography allows qualitative and quantitative assessment of lymph node stiffness. This article reviews the value of greyscale, Doppler and contrast-enhanced ultrasonography as well as elastography in the assessment of malignant nodes in the neck.

A short review of basic head and neck interventional procedures in a general radiology department

Image-guided interventional procedures provide a safe way to diagnose and treat a variety of head and neck abnormalities. The procedure time is usually short, and most procedures can be performed on an outpatient basis. Knowledge about strengths and weaknesses, efficacy, potential complications, and pitfalls of these procedures allows the best treatment to be chosen for a particular lesion type. This review discusses some of the commonly performed interventional radiology procedures in a general radiology department in the management of patients with neoplastic diseases in the head and neck region.

Unusual parotid gland lesions: a pictorial review

This is a pictorial essay of unusual parotid gland lesions that may be encountered in routine clinical practice.

Use of end-cutting needles in ultrasound-guided biopsy of neck lesions

The management of a neck mass is dictated by its nature, location and extent. Pathological diagnosis by fine needle aspiration cytology (FNAC) or core biopsy is often required before proceeding to definitive treatment. It is not uncommon for the cytology result to come back as inadequate for various reasons. The unique design of the end-cutting biopsy needle in our experience makes it a good choice for use in obtaining both transcutaneous and intraoral biopsy under ultrasound guidance of neck lesions and serves as a useful alternative or adjunct to FNAC. Although there is, as yet, only a limited evidence base about end-cutting in comparison to side-cutting needles, they carry several potential advantages.

KEY POINTS

End-cutting needles are safe to use for lesions close to vital structures. End-cutting needles yield sufficient tissue samples in a single pass. End-cutting biopsy needles are a useful adjunct to FNAC.

Salivary Gland Tumors at in Vivo Proton MR Spectroscopy

PURPOSE

To prospectively evaluate whether proton magnetic resonance (MR) spectroscopy can be used to characterize salivary gland tumors (SGTs).

MATERIALS AND METHODS

Ethics committee approval and informed consent were obtained. Hydrogen 1 ((1)H) MR spectroscopy was performed with echo times of 136 and 272 msec at 1.5 T in both SGTs and normal parotid glands. Spectra were analyzed in the time domain by using prior knowledge in the fitting procedure to obtain peak amplitudes of choline (Cho), creatine (Cr), and unsuppressed water. Mean Cho/Cr and Cho/water ratios for each subgroup of SGTs were obtained, and results were compared by using a nonparametric t test.

RESULTS

Successful spectra were acquired in 56 patients (35 men, 21 women; mean age, 56 years) with a total of nine malignant tumors and 47 benign SGTs (24 Warthin tumors, 22 pleomorphic adenomas, one oncocytoma). At an echo time of 136 msec, Cho/Cr ratios were obtained in 26 (47%) of 55 spectra, with a mean value (+/- standard deviation) of 1.73 +/- 0.47, 5.49 +/- 1.86, 3.46 +/- 0.84, and 2.45 for malignant tumors, Warthin tumors, pleomorphic adenomas, and oncocytoma, respectively. Differences were significant between Warthin tumors and pleomorphic adenomas (P = .028) and between benign SGTs and malignant tumors (P < .001). At an echo time of 272 msec, Cho/Cr ratios were obtained in 16 (30%) of 53 spectra, with a mean value of 2.27 +/- 0.69, 6.92 +/- 1.47, and 3.67 +/- 1.23 for malignant tumors, Warthin tumors, and pleomorphic adenomas, respectively. Differences were also significant between Warthin tumors and pleomorphic adenomas (P = .041) and benign SGTs and malignant tumors (P = .004). There was a significant difference in mean Cho/water ratio for Warthin tumors versus pleomorphic adenomas at echo times of 136 msec (P = .003) and 272 msec (P = .002) but not for benign SGTs versus malignant tumors.

CONCLUSION

(1)H MR spectroscopy may be used to characterize SGTs, but a larger study is required to validate these initial results.

Grey-scale and power Doppler sonography of unusual cervical lymphadenopathy

This study was undertaken to document the grey-scale and power Doppler sonographic features of cervical lymphadenopathy in Kikuchi's disease (histiocytic necrotising lymphadenitis), Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy), Sjogren's syndrome and systemic lupus erythematosus (SLE), which have not been reported in the literature. A retrospective review of the grey-scale and power Doppler sonograms of the cervical lymph nodes in nine patients was conducted (Kikuchi's disease, n = 3; Rosai-Dorfman disease, n = 1; Sjogren's syndrome, n = 1; SLE, n = 4). Lymph nodes were proven to be pathologic by fine-needle aspiration cytology (FNAC). On grey-scale ultrasound (US), lymph nodes were assessed by their distribution, size, shape, echogenicity and internal architecture. The vascular pattern of the lymph nodes was assessed with power Doppler sonography. US features of the lymph nodes were compared to those of metastatic and reactive nodes. In Kikuchi's disease, Rosai-Dorfman disease, Sjogren's syndrome and SLE, the distribution of lymph nodes is similar to that of reactive nodes. Most of the lymph nodes are enlarged with a maximum transverse diameter greater than or equal to 10 mm (83.3 to 100%). In Kikuchi's disease, lymph nodes have grey-scale and Doppler appearances similar to reactive nodes. However, lymph nodes in Rosai-Dorfman disease, Sjogren's syndrome and SLE show similar grey-scale and Doppler features to metastatic nodes. There is no specific US feature to characterise lymphadenopathy from these four miscellaneous causes. Definitive diagnosis should still be based on cytology and histology, and US can help in guiding FNAC for a more accurate cytologic examination.

Computed tomography imaging of the temporal bone--normal anatomy

This review describes the fundamental anatomical structures of the temporal bone as depicted on high-resolution computed tomography, and the clinical significance of these structures. It is not an encyclopaedic atlas, but provides the junior radiology/otorhinolaryngology resident with sufficient knowledge for interpretation of most of the imaging studies encountered in daily clinical practice.

Computed tomography of common congenital lesions of the temporal bone

This pictorial review describes the application of high-resolution computed tomography to the investigation and pre-operative work-up of the common lesions of congenital hearing loss, including congenital aural dysplasia, various congenital ossicular anomalies, inner ear dysmorphology, large vestibular aqueduct syndrome, and congenital absence of cochlear nerve and labyrinthitis ossificans from previous infection. The aim is to help radiologists to provide a more accurate diagnosis of underlying aetiology and assist in surgical planning.

Kuttner tumour (chronic sclerosing sialadenitis) of the submandibular gland: sonographic appearances

Patients with Kuttner tumours present with clinical features simulating a submandibular tumour. This article aims to familiarise sonologists with the sonographic appearances of these tumours, to help in their differentiation from other salivary lesions. In 13 patients with histologically or cytologically proven Kuttner tumours, the features evaluated on sonography included: shape and border of the gland, internal architecture, duct dilatation, presence/absence of calculi and presence and distribution of vascularity. There was diffuse involvement of the submandibular glands in 11 patients and focal involvement in 2. The majority (9 of 11) of the patients with diffuse involvement showed sonographic appearances simulating a "cirrhotic" liver; 2 showed diffuse heterogeneous involvement with duct dilatation and calculus. Doppler showed prominent intraglandular vessels, with no evidence of displacement. Focal lesions (2 of 11) were seen as hypoechoic, heterogeneous "masses," with a radial branching vascular pattern within, on Doppler. In conclusion, sonographic features may help in identifying Kuttner tumours of the submandibular glands.

Sonographic characterisation of radiation-induced carotid artery stenosis

BACKGROUND AND PURPOSE

To study the distribution, extent and sonographic characterisation of radiation-induced carotid artery stenosis in nasopharyngeal carcinoma (NPC) patients.

METHODS

The distribution of plaques, the extent of stenosis, and the sonographic characterisation of the plaque at maximum stenosis were recorded in 71 NPC patients. The results were compared with the ultrasound results of a control group of 142 patients presenting with symptoms of cerebrovascular disease or carotid bruit.

RESULTS

NPC patients had a higher incidence of carotid stenosis (77 vs. 50.7%). The common carotid arteries were most commonly affected by radiation-induced stenosis (93/142 vs. 37/284 in the control group), whereas the carotid bulb was the most commonly affected (56/284) site in the control group. Significantly more NPC patients had moderate-to-severe stenosis (21/71 vs. 27/142). Analysis of the sonographic appearance of radiation-induced and atherosclerotic plaques showed more diffuse involvement in the post-radiation group. Non-calcified plaques and intraplaque hypoechoic foci were also more frequent in the post-radiation group.

CONCLUSIONS

Radiation-induced carotid stenosis is more diffuse in distribution, is associated with more severe luminal stenosis and has different sonographic plaque characterisation compared with carotid stenosis without radiation exposure.

Incidence of carotid stenosis in nasopharyngeal carcinoma patients after radiotherapy

BACKGROUND

Radiation-induced carotid stenosis in patients with head and neck tumors can cause significant mortality and morbidity. This study examined the incidence of stenosis in the extracranial carotid arteries of nasopharyngeal carcinoma patients after radiotherapy.

METHODS

The extracranial carotid arteries of 71 (53 male and 18 female; mean age of 53.6 years) postradiation patients with nasopharyngeal carcinoma were examined with color Doppler ultrasound. The distribution of the arterial stenosis and the degree of stenosis were documented. The results were compared with the control group, which comprised 51 newly diagnosed nasopharyngeal carcinoma patients (35 male and 16 female, mean age of 48.8 years) before radiotherapy. Incidences of risk factors for arterial stenosis such as hypertension, smoking, and hypercholesterolemia also were studied in these two groups.

RESULTS

There was no significant difference in the incidence of risk factors between the two groups. Arterial stenosis was, however, more common in the postradiation group than the preradiation group (56 of 71 vs. 11 of 51). The common/internal carotid arteries (CCA/ICA) were most commonly involved (55 of 71 vs. 11 of 51; P < 0.01), followed by the external carotid artery (ECA) (32 of 71 vs. 1 of 51; P < 0.01) and vertebral artery (VA; 5 of 71 vs. 0; P = 0.069). Significant stenosis (> 50% reduction of luminal diameter) was only found in the postradiation group (21 of 71 in CCA/ICA, 11 of 71 in ECA, 4 of 71 in VA).

CONCLUSIONS

This study showed that radiation could cause significant carotid stenosis. Ultrasound examinations for these patients therefore are necessary for early detection and possible intervention of this late radiation-induced complication.

Clinically underdetected asymptomatic and symptomatic carotid stenosis as a late complication of radiotherapy in Chinese nasopharyngeal carcinoma patients

BACKGROUND

Carotid artery stenosis is a late complication of radiotherapy to the neck region. This complication has, however, a significant impact with increased risk of stroke causing mortality and morbidity. Clinicians' awareness of this complication and early detection is therefore important.

METHODS

Eighty patients with nasopharyngeal carcinoma (NPC) who had received radiotherapy were recruited for color Doppler ultrasonography of the carotid arteries. fifty-eight patients with newly diagnosed NPC who had never received any radiotherapy were recruited as controls. All patients with significant carotid stenosis were referred to the neurology clinic for further assessment.

RESULTS

Twenty-four patients were found to have more than 50% diameter reduction in the extracranial carotid artery. Clinical assessment by a neurologist showed 9 of 24 patients had a history of transient ischemic attack, amaurosis fugax, or stroke. Seven of these patients had clinically detectable neck bruit.

CONCLUSIONS

Clinicians attending to patients after radiotherapy for head and neck cancers should be aware of this long-term complication of radiotherapy. A detailed clinical history and incorporation of auscultation of carotid arteries in routine follow-up of postradiotherapy patients are recommended.

Lymph node hilus: gray scale and power Doppler sonography of cervical nodes

OBJECTIVE

To investigate the difference in the nodal hilus evaluated by gray scale and power Doppler sonography.

METHODS

One hundred ninety-two patients with proven cervical lymphadenopathy were included in the study (metastases, n = 118; tuberculosis, n = 56; and lymphoma, n = 18). Lymph nodes were evaluated by gray scale sonography for the echogenic hilus and power Doppler sonography for hilar vascularity.

RESULTS

Hilar vascularity was found even though the lymph node did not show an echogenic hilus on gray scale sonography (metastases, 59%; tuberculosis, 66%; and lymphoma, 91%).

CONCLUSIONS

Sonologists should be aware that gray scale and Doppler sonography show different aspects of the hilus, and the absence of the hilus on gray scale sonography does not necessarily imply an associated absence of hilar vascularity.

Comparison of CT virtual endoscopy with electronic colonoscopy in 30 colonic carcinoma patients

OBJECTIVE

To evaluate the clinical application of CT virtual endoscopy (CTVE) in the diagnosis and treatment of colonic carcinoma.

METHODS

We collected 30 patients pathologically proven to have colonic carcinomas as examined by CTVE and electronic colonoscopy (EC), correlating the CTVE and EC images respectively with surgical pathology in three aspects: tumor morphological features, degree of circumferential bowel wall involvement and longitudinal extent of tumor.

RESULTS

CTVE imaging of colonic carcinomas showed morphological features: polypoid pattern (11 patients), ulcerative pattern (11), and infiltrative pattern (8); degree of circumferential bowel wall involvement: less than 1/2 (4 patients), from 1/2 to 3/4 (6), and more than 3/4 (20); and their longitudinal extent: 1.0-3.0 cm (7 patients), 31-5.0 cm (10), and 5.1-11.0 cm (13). Correlation of CTVE and EC with surgical pathology was found. Comparison of CTVE with surgical pathology showed tumor morphological features: concordant (26 patients), and disconcordant (4); degree of circumferential bowel wall involvement: concordant (25), disconcordant (5); and longitudinal extent of the tumor: concordant (23), disconcordant (7). Comparison of EC with surgical pathology showed tumor morphological features: concordant (22 patients), disconcordant (8); degree of circumferential bowel wall involvement: concordant (28), disconcordant (2); and longitudinal extent of the tumor: concordant (14), disconcordant (3), and undefined by EC (13).

CONCLUSIONS

The images obtained by CTVE in colonic carcinoma are similar to those obtained by EC. CTVE is an excellent alternative to EC for patients who cannot tolerate EC and for cases with incomplete EC.

Power Doppler sonography of metastatic nodes from papillary carcinoma of the thyroid

AIMS

Metastatic nodes on power Doppler sonography tend to demonstrate high intranodal resistance and abnormal distribution of vascularity within a node. However, in our experience metastatic nodes from papillary carcinoma of the thyroid frequently demonstrate low intranodal resistance and some do not demonstrate the presence of any abnormal vascularity within. We were therefore interested to document these features.

MATERIALS AND METHODS

The grey scale and power Doppler sonograms of 21 metastatic nodes from papillary carcinoma of the thyroid were evaluated. The intranodal distribution of vessels and the intranodal vascular resistance of vessels was assessed and compared with the reported features of metastatic nodes from other head and neck primaries.

RESULTS

A majority (17/20, 85%) of metastatic nodes from papillary carcinoma of the thyroid had a maximum resistance index (RI) and pulsatility index (PI) < 0.8 and 1.6, respectively. A majority of the nodes (16/21, 76%) demonstrated abnormal capsular vascularity within the nodes.

CONCLUSION

Metastatic nodes from papillary carcinoma on power Doppler sonography frequently have low RI and PI and 24% demonstrate just prominent hilar vascularity similar to reactive nodes.

'Pseudocystic' appearance of non-Hodgkin's lymphomatous nodes: an infrequent finding with high-resolution transducers

AIMS

A pseudo-cystic appearance and posterior enhancement are previously reported to be diagnostic sonographic features of lymph node involvement in non-Hodgkin's lymphoma. This study was undertaken to determine whether these ultrasonic features remain with the use of high-resolution transducers.

MATERIAL AND METHODS

A review of ultrasound examinations in 32 patients with proven lymphomatous cervical lymphadenopathy (27 non-Hodgkin's lymphoma, five Hodgkin's disease) was performed. A total of 95 lymph nodes were assessed for size, shape, posterior enhancement and internal architecture. All examinations were performed with the same high-resolution transducer and by the same sonologist.

RESULTS

Lymphomatous nodes (irrespective of type) are frequently heterogeneous (68-86%), have a micronodular pattern (63-69%) and less commonly demonstrate posterior enhancement (9-26%).

CONCLUSION

Using a high-resolution ultrasonic transducer, cervical nodes involved with lymphoma (irrespective of type) commonly demonstrate a heterogeneous micronodular pattern. The pseudocystic appearance of nodes with posterior enhancement in non-Hodgkin's nodes is seen infrequently.