Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Merkel Cells”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,693 records · Page 94Linked to original sources
PubMed1998

[Endorectal MRI and ultrasonography in rectal tumors: correlation with histological staging].

PURPOSE: To compare the accuracy of high resolution endorectal magnetic resonance imaging (EMRI) and endorectal ultrasound (EUS) in the preoperative diagnostic of rectal tumours. PATIENTS AND METHODS: Twenty-one patients with known rectal tumours underwent MR imaging with an endorectal surface coil and EUS. Transversal EMR images were obtained using fast T2-weighted sequences and pre- and postcontrast T1-weighted images. EUS was performed using a 7.0 MHz transducer. Results of both methods were compared with specimens from the resected tumours. RESULTS: Rectal wall layers were reliably demonstrated with both methods in all patients. EMRI and EUS determined the depth of rectal wall invasion. EMRI and EUS agreed with pathologic findings in 16/21 cases, respectively. In one case each, both methods understaged one tumour. EMRI overstaged an adenoma as a T2-tumour. In three and four patients, respectively, no staging was possible due to technical problems. CONCLUSION: EMRI and EUS show comparable results in the preoperative T-staging of rectal tumours. Both techniques are not suitable for differentiating benign from malignant lymph nodes accurately. While EMRI is expensive and technically demanding, it allows an objective documentation of pathological findings which is less dependent on the examiner. Two important clinical conclusions can be drawn from the good results of T-staging: Adenomas and T1-tumours can be treated by local excision. In patients with advanced tumours (T3/T4) a neoadjuvant therapy can be initiated.

Adenoma↗
PubMed2006

Neuroanatomical evidence for segregation of nerve fibers conveying light touch and pain sensation in Eimer's organ of the mole.

Talpid moles are small insectivores that live in dark underground tunnels. They depend heavily on touch to navigate and find food. Most species have an array of complex epidermal sensory structures called Eimer's organs that cover the tip of the nose. In this study, the anatomy of Eimer's organ was examined in the coast mole and star-nosed mole by using the fluorescent styryl pyridinium dye AM1-43 and immunocytochemical staining for neurofilament 200 and substance P. In addition, DiI was used to label neural components of Eimer's organ. AM1-43 labeled all of the Eimer's organ receptors after systemic injection, suggesting a role in mechanotransduction. Immunostaining with neurofilament 200 and substance P labeled distinct subtypes of sensory fibers. Substance P labeled a group of free nerve endings along the outer edge of Eimer's organ, indicating a nociceptive role for these fibers. In contrast, neurofilament 200 labeled a more central set of nerve endings, suggesting that these fibers function as low-threshold mechanoreceptors. By labeling subsets of trigeminal afferents distant from the receptor array with DiI, we revealed innervation patterns indicating that one afferent supplies the outer, substance P-positive set of free nerve endings, whereas several afferents differentially innervate the central free nerve endings. Our results suggest that the free nerve endings innervating Eimer's organ are largely mechanosensitive and may play an important role in the rapid sensory discrimination observed in these species.

Afferent Pathways↗
PubMed2002

Effects of stimulus duration on neuronal response properties in the somatosensory cortex of the star-nosed mole.

Star-nosed moles have a series of mechanosensory appendages surrounding each nostril. Each appendage is covered with sensory organs (Eimer's organs) containing both rapidly adapting and slowly adapting mechanoreceptors and each appendage is represented in primary somatosensory cortex (S1) by a single cortical module. When the skin surface of an appendage is depressed, neurons in the corresponding module in S1 respond in either a transient or sustained fashion. The aim of this study was to characterize and compare the responses of these two classes of neurons to both short (5 or 20 ms) and long (500 ms) mechanosensory stimulation. Activity from neurons in the representation of appendage 11, the somatosensory fovea, was recorded while delivering mechanosensory stimuli to the corresponding skin surface. Transient and sustained neurons had different levels of spontaneous activity and different responses to both short and long mechanosensory stimulation. Neurons with sustained responses had a significantly higher spontaneous firing rate than neurons with transient responses. Transient neurons responded to a 5 ms stimulus with excitation followed by suppression of discharge whereas sustained neurons did not exhibit post-excitatory suppression. Rather, responses of sustained neurons to 5 ms stimuli lasted several hundred milliseconds. Consequently sustained responses contained significantly more spikes than transient responses. These experiments suggest contact to the appendages causes two distinct firing patterns in cortex regardless of the duration of the stimulus. The sustained and transient responses could reflect either the activity of fundamentally different classes of neurons or activity in distinct subcortical and cortical networks.

Afferent Pathways↗
PubMed2003

Effects of temperature on the subjective magnitude of vibration.

Absolute magnitude estimation (AME) was used to determine the effects of skin temperature on the subjective magnitude of vibration delivered to the thenar eminence of the right hand. Measurements were made at three frequencies chosen to selectively activate cutaneous mechanoreceptor channels, namely NP I and NP III (Meissner and Merkel cell-neurite receptors, respectively) at 15 Hz, Pacinian (250 Hz, 400 Hz) and NP III (Ruffini endings) at 400 Hz. Skin temperatures at 15, 20 and 40 degrees C were tested at 11 suprathreshold displacement levels. It was concluded that the subjective magnitude of vibration is influenced by temperature in the Pacinian channel, but in the NP I and NP III channels the temperature of the skin did not have an effect upon judgements of subjective magnitude. This is consistent with earlier work by Verrillo and Bolanowski (J Acoust Soc Am 80: 528-532, 1986) and Bolanowski et al. (J Acoust Soc Am 84: 1680-1694, 1988); both studies show only modest effects of temperature at threshold at frequencies below approximately 40 Hz.

Adult↗
PubMed2000

A skin lesion found by serendipity.

A 77-year-old retired postal worker presented with symptoms of recurrent aspiration pneumonia, for which he had last been seen one month earlier. Oropharyngeal dysfunction, presumably caused by previous strokes, was demonstrated by video-esophagoscopy, and a percutaneous gastrostomy tube was placed at that time.

Aged↗
PubMed2001

Clinical significance of blood chromogranin A measurement in neuroendocrine tumours.

BACKGROUND: Tumour marker measurement gives clinicians useful information for the follow-up and management of patients with neuroendocrine tumours (NETs). The currently used tumour markers for NETs are neuron-specific enolase (NSE) and chromogranin A (CgA). The clinical accuracy of these biomarkers depends on histotype and disease extent. CgA is thought to be the optimal marker for most NETs, as it is independent of the biological characteristics of the tumour. AIM OF THE STUDY: In this study we investigated the value of CgA assessment with respect to the other biomarkers in the diagnosis and follow-up of patients with different types of NETs. PATIENTS AIND METHODS: We measured CgA, NSE, carcinoembryonic antigen (CEA) and urine 5-hydroxy-3-indoleacetic acid (5-HIAA) in 290 patients with 127 gastroenteropancreatic (GEP) tumours, 49 neuroblastomas, 36 lung tumours, 24 medullary thyroid carcinomas (MTCs). 15 pNETs, 12 paragangliomas. 7 Merkel's cell carcinomas (MCCs) and 20 NETs of unknown origin. CgA and 5-HIAA were quantitated by immunoenzymatic assays, while NSE and CEA were determined by radioimmunoassays. RESULTS: The biomarkers' specificity in GEP tumours was 86% for CgA, 100% for NSE, 91% for CEA and 100% for 5-HIAA. The corresponding sensitivity was 68% for CgA, 33% for NSE, 15.4% for CEA and 35% for 5-HIAA. The sensitivity of CgA largely depends on disease extent or presence of functioning tumours and is highest in metastatic and syndromic patients. CgA determination in GEP tumour monitoring is useful to evaluate the response to therapy and to follow up patients with liver metastases. In neuroblastomas the overall specificity of NSE and CgA was 50%, and 83%, respectively. In these tumours NSE sensitivity was close to 90% in all clinical stages, while the sensitivity of CgA depended on clinical stage (50% for stage I and II, 60% for stage III and 100% for stage IV tumours). Also in this type of tumour changes in CgA levels correlated with objective response. In paragangliomas CgA measurement may provide useful clinical information. Measurement of CgA is of use in the diagnosis of lung carcinoids, while its value in MTCs, pNETs and MCCs is very limited. CONCLUSIONS: CgA was confirmed to be the best tumour marker currently available for identifying patients suffering from NETs of the GEP system, lung carcinoids and neuroblastomas. CgA evaluation is recommended in the follow-up of patients with such tumours.

Biomarkers, Tumor↗
PubMed2002

Stepladder dorsal metacarpal flaps for dorsal finger and hand reconstruction.

The authors demonstrate successful cases of stepladder dorsal metacarpal V-Y advancement and rotation-advancement flaps for reconstructing defects on the dorsum of the finger and hand. One side of the flap is designed in a multilobed shape, and each lobed flap is designed on the dorsum of adjacent fingers. These flaps are supplied by dorsal metacarpal vessels. Consequently, this method has the elements of the stepped incision technique, in combination with the V-Y and rotation-advancement principle. All flaps survived completely. This technique may be a useful option for reconstruction of defects of the dorsum of the finger and hand.

Bowen's Disease↗
PubMed2002

Split thoracodorsal nerve funicular graft combined with functional latissimus dorsi musculocutaneous flap transfer for immediate facial reanimation after tumor ablation.

The authors report a case of immediate facial reanimation resulting from functional latissimus dorsi musculocutaneous flap transfer and funicular grafting of the thoracodorsal nerve after cheek tumor ablation. After wide excision of the tumor, including the facial nerve except the temporal branch and part of the zygomatic major muscle and masseter muscle, the authors reconstructed the cheek skin and provided movement by performing a small-segment latissimus dorsi musculocutaneous flap transfer using Harii's method and the defect of the buccal and marginal mandibular branches of the facial nerve by funicular grafting from one of the two funicles of the thoracodorsal nerve. After 6 months, the transplanted, small-segment latissimus dorsi muscle showed good voluntary movement, and the lower orbiculus oris and depressor oris presented good functional recovery. The authors believe the two funicles of the thoracodorsal nerve can be used independently for two purposes: one for functional segmental muscle transfer and the other for nerve grafting to defects of branches of the facial nerve. This concept makes it possible to reconstruct multiple facial movements while minimizing donor site morbidity by means of immediate facial reanimation.

Aged↗
PubMed2004

Head and neck cancer in transplant recipients.

PURPOSE OF REVIEW: Transplant recipients have an increased incidence of cancer compared with the general population. Head and neck sites are involved in more than 50% of patients, and as a result the otolaryngologist should be familiar with the diagnosis and management of posttransplant malignancies. RECENT FINDINGS: Skin cancer is the most common malignancy encountered in the transplant population, and in areas of high sun exposure, as many as 80% of patients are affected. Patients who undergo liver transplantation for alcoholic cirrhosis appear to be at particularly increased risk for developing posttransplant malignancy of the head and neck. A number of uncommon malignancies such as Kaposi's sarcoma occur with a greatly increased incidence in transplant recipients. Malignancy in this patient population tends to present at a younger age compared with the general population, with a more aggressive course and poorer outcomes reported. SUMMARY: A high index of suspicion may reduce morbidity and mortality through early detection of malignant disease in the transplant recipient.

Carcinoma, Merkel Cell↗
PubMed2006

Upper eyelid reconstruction with a hard palate mucosa-lined bipedicled myocutaneous flap.

The upper eyelid is very difficult to reconstruct because smooth opening and closure of the eyelid must be maintained. A patient is presented in whom a hard palate mucosa-lined bipedicled myocutaneous flap containing innervated orbicularis oculi was used to successfully reconstruct a subtotal upper eyelid defect. Good functional and aesthetic results were achieved. This method may be a good alternative for reconstruction of large upper eyelid defects.

Aged, 80 and over↗