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Cystic fibrosis, vasoactive intestinal polypeptide, and active cutaneous vasodilation.

The transmitter substance for the active cutaneous vasodilation that accompanies sweating during hyperthermia in humans is unknown. Hökfelt et al. (Nature Lond. 284: 515-521, 180) hypothesized that it is vasoactive intestinal polypeptide (VIP) that is cotransmitted with acetylcholine. Heinz-Erian et al. (Science Wash. DC 229: 1407-1408, 1985) reported that VIP innervation is sparse in the skin of persons with cystic fibrosis (CF). A corresponding attenuation of active vasodilation in these subjects would be evidence that VIP is involved in this effector mechanism of human thermor-regulation. Immunocytochemical analysis of skin biopsies from four men with CF confirmed that VIP innervation was sparse. We also analyzed immunoreactivity for calcitonin gene-related peptide (CGRP; normal), substance P (normal), and neuropeptide Y (low). VIP-immunoreactive Merkel cells were abnormal. Despite sparse VIP-immunoreactive innervation, our CF subjects' cutaneous vascular responses to hyperthermia were normal. Because VIP was not completely absent, this evidence is insufficient to rule out VIP as the vasodilator transmitter. However, the CGRP and substance P innervation we observed could mean that release of one or both of these peptides was the mechanism of the fully developed active cutaneous vasodilation.

Adult↗

Receptive properties of mouse sensory neurons innervating hairy skin.

Using an in vitro nerve skin preparation and controlled mechanical or thermal stimuli, we analyzed the receptive properties of 277 mechanosensitive single primary afferents with myelinated (n = 251) or unmyelinated (n = 26) axons innervating the hairy skin in adult or 2-wk-old mice. Afferents were recorded from small filaments of either sural or saphenous nerves in an outbred mice strain or in the inbred Balb/c strain. On the basis of their receptive properties and conduction velocity, several receptor types could be distinguished. In adult animals (>6 wk old), 54% of the large myelinated fibers (Abeta, n = 83) showed rapidly adapting (RA) discharges to constant force stimuli and probably innervated hair follicles, whereas 46% displayed a slowly adapting (SA) response and probably innervated Merkel cells in touch domes. Among thin myelinated fibers (Adelta, n = 91), 34% were sensitive D hair receptors and 66% were high-threshold mechanoreceptors (AM fibers). Unmyelinated fibers had high mechanical thresholds and nociceptive functions. All receptor types had characteristic stimulus-response functions to suprathreshold force stimuli. Noxious heat stimuli (15-s ramp from 32 to 47 degrees C measured at the corium side of the skin) excited 26% (5 of 19) of AM fibers with a threshold of 42.5 +/- 1.4 degrees C (mean +/- SE) and an average discharge of 15.8 +/- 9.7 action potentials and 41% (7 of 17) C fibers with a mean threshold of 37.6 +/- 1.9 degrees C and an average discharge of 22.0 +/- 6.0 action potentials. Noxious cold stimuli activated 1 of 10 AM fibers and 3 of 10 C fibers. One of 10 C units responded to both heat and cold stimuli. All types of afferent fibers present in adult mice could readily be recognized in mice at postnatal day 14. However, fibers had reduced conduction velocities and the stimulus-response function to mechanical stimuli was more shallow in all fibers except for the D hairs. In juvenile mice, 22% of RA units also displayed an SA response at high stimulus intensities; these units were termed RA/SA units. We conclude that all types of cutaneous afferent fibers are already committed to their phenotype 2 wk after birth but undergo some maturation over the following weeks. This preparation has great potential for the study of transgenic mice with targeted mutations of genes that code factors that are involved in the specification of sensory neuron phenotypes.

Afferent Pathways↗

Supranumerary barrels develop in the somatosensory cortex of mice, after the implantation of the vibrissal follicle parts containing large numbers of receptors.

In the mouse whiskerpad there is a group of vibrissal follicles arranged in five rows, which are topologically represented in the contralateral somatosensory cortex by the barrelfield. Each vibrissal follicle is a specialized sensory organ containing a large number of receptors, mostly Merkel cells. In these experiments, the parts of the vibrissal follicles containing most of the receptors were transplanted to different regions of the whiskerpad of newborn mice, to know whether "new", supranumerary barrels could develop. The results confirm this hypothesis. However, the "new" barrels are not topologically represented in the barrelfield, as normal barrels do.

Animals↗

Primary neuroendocrine carcinoma of inguinal lymph node.

Ninety-seven percent of neuroendocrine carcinomas are located in the gastrointestinal tract or in the bronchopulmonary tree. Inguinal lymph nodes as the primary tumor site for neuroendocrine carcinoma represent a very unusual location, and have only been described in 2 patient series in the literature. A 64-year-old, previously healthy, Caucasian female presented with a 2-month history of an enlarged inguinal lymph node on the right side. The removed lymph node showed histological and immunohistochemical characteristics of neuroendocrine differentiation (positive for synaptophysin, cytokeratin 20, neuron-specific enolase and chromogranin A). Although extensive investigations including repeated CT and NMR scans, classical endoscopy, wireless capsule endoscopy of the small intestine, octreotide- and MIBG scintigraphy were performed, no other primary tumor was found. Furthermore, there was no evidence of Merkel cell carcinoma on dermatological examinations. A possible explanation for the presence of neuroendocrine carcinomas within the lymph nodes is malignant transformation of preexisting intranodal epithelial nests, which have previously been described in lymph nodes located close to the salivary glands, thyroid gland, breast tissue and pancreas. Since the surgical removal of the affected lymph node, the patient has now been disease-free for 42 months. We therefore consider our case to represent a primary undifferentiated neuroendocrine carcinoma in an inguinal lymph node.

Carcinoma, Neuroendocrine↗

Ultrastructure and distribution of epidermal sensory receptors in the beak of the echidna, Tachyglossus aculeatus.

Within the rostral one centimetre of the Echidna beak, three specialised receptors were found: a mucous sensory gland, a rod-like structure, and an innervated epidermal pit. The mucous sensory gland consists of a dermal mucous gland and a modified epidermal portion. Bulbous nerve terminals, similar to those reported for the Platypus, were found within the modified epidermal portion of the mucous gland. The rod-like structure contains four types of nerve terminals: Merkel cells, Paciniform corpuscles, and a central and a peripheral vesicle chain receptor. Apart from minor differences, the rod-like structure is similar to that previously reported for the Platypus. Preliminary results are presented for a third structure: an innervated epidermal pit. Topographical and ultrastructural analyses are used in the context of functional interpretation.

Animals↗

Structural development in the newborn marsupial, the stripe-faced dunnart, Sminthopsis macroura.

The structure of various sense organs and endocrine glands was examined in the stripe-faced dunnart, Sminthopsis macroura. This marsupial has the shortest gestation known for all mammals, 10.5-11 days. The morphology of the anterior pituitary, adrenal gland, olfactory epithelium, Merkel cells around the mouth and the utricle of the vestibular system of S. macroura was similar to that observed in other newborn marsupials. These structures are thought to be required by the newborn to transfer from the uterus to the pouch. The stage of development of the urinary system, the semicircular canals of the vestibular system, eyes and lungs was slightly different to that of other newborn marsupials. These structures are thought to have secondary importance in allowing the newborn to reach the teat. Although marsupials display variation in gestation length and produce newborn of differing body weights, there is little difference in morphology between various newborn marsupial species.

Animals↗

[Established nuclear medicine techniques for tumour diagnosis (tumour SPECT): can they still compete with (18)F-FDG-PET?].

This overview presents the indications of tumour SPECT in contrast to tumour PET using (18)F-FDG. A number of diagnostic SPECT radiopharmaceuticals have been used for years in oncology and are widely available in nuclear medicine departments. Today, tumour SPECT has to compete with tumour PET using (18)F-FDG. Other PET radiopharmaceuticals are common only in specialised centers. In comparison to SPECT, PET images with their higher resolution are technically superior. Therefore, PET is better than SPECT in localising a tumour, if the special tumour entity accumulates (18)F-FDG. Thus, (18)F-FDG-PET has largely replaced SPECT examinations using (201)Tl chloride, (67)Ga citrate or (99m)Tc anti-CEA. It is questionable whether mammascintigraphy using (99m)Tc-MIBI or (99m)Tctetrofosmine will be broadly accepted in clinical routine. SPECT radiopharmaceuticals are still up to date for examination of tumour entities which do not accumulate (18)F-FDG (e. g. neuroendocrine tumours) and in clinical problem solving if (18)F-FDG-PET is not regarded as superior (e. g. search for recurrent medullary thyroid carcinoma) or in the management of tumours with overlapping diagnosis and therapy as it is the case for differentiated thyroid carcinomas ((123)I/(131)I-NaI), phaeochromozytomas, and neuroblastomas ((123)I/(131)I-MIBG), carcinoids, gastroenteropancreatic tumours, paragangliomas, and Merkel-cell tumours (somatostatin receptor scintigraphy). Future developments concerning new SPECT radiopharmaceuticals and image fusion such as SPECT/CT are expected.

Fluorodeoxyglucose F18↗

MR lymphangiography using ultrasmall superparamagnetic iron oxide in patients with primary abdominal and pelvic malignancies: radiographic-pathologic correlation.

OBJECTIVE: The purpose of this study was to administer ultrasmall superparamagnetic iron oxide (USPIO) and compare changes in signal intensity of lymph nodes in patients with primary abdominal and pelvic malignancies. Also, we correlated radiographic with pathologic findings. SUBJECTS AND METHODS: Nineteen patients with proven primary abdominal or pelvic cancer (prostatic [n = 10]; colonic [n = 5]; endometrial [n = 1]; Merkel cell tumor [n = 1]; lymphoma [n = 1]; seminoma [n = 1]) were enrolled as part of our phase II and phase III clinical trials. In these patients, 49 lymph nodes (mean size, 1.4 cm) revealed on CT or MR imaging were evaluated on T1-weighted spin-echo, T2-weighted fast spin-echo, and T2*-weighted gradient-echo MR imaging at 1.5 T 24-36 hr after IV administration of USPIO. Quantitative analyses used measurements of unenhanced and enhanced region-of-interest values in lymph nodes. Qualitative assessment used subjective evaluation and classification of changes in signal intensity. All patients underwent lymph node biopsy or surgical dissection followed by histopathologic correlation. RESULTS: Of the 49 lymph nodes that were evaluated, 20 were benign and 29 were malignant. A decrease in nodal signal intensity on enhanced T2-weighted and T2*-weighted gradient-echo images was seen in 20 benign lymph nodes and two malignant lymph nodes. No appreciable signal change was noted in 27 of the 29 malignant lymph nodes. The mean signal intensity on fast spin-echo T2-weighted images for benign lymph nodes changed from 186.48 (unenhanced) to 73.66 (enhanced). Conversely, mean signal intensity for malignant lymph nodes was relatively unchanged from 191.17 (unenhanced) to 183.18 (enhanced). CONCLUSION: USPIO appears to be a useful MR contrast agent for characterizing benign and malignant lymph nodes based on the enhancement criteria evaluated in our study.

Abdominal Neoplasms↗

Neuroendocrine skin carcinoma coexpressing cytokeratin and neurofilament proteins.

Neuroendocrine (Merkel cell) carcinomas of the skin have been recognized as such for several years. Given the reported wide variability in the morphology and clinical evolution of these tumors, the notion that may they comprise several variants rather than a single type has been advocated. Electron microscopy has played a key role in the early recognition of these tumors while immunohistochemical studies for various neuroendocrine markers have facilitated their subsequent diagnosis and improved our understanding as to their complexity by the demonstration of immunoreactivity for NSE (neuron specific enolase) and a number of neuropeptides. There has also been considerable interest in the study of the cytoskeletal intermediate filament complement of neuroendocrine neoplasms in general and of those of the skin in particular. Early reports indicated that neuroendocrine skin carcinomas had neurofilaments while subsequent investigations determined that they had cytokeratin. However, more recent studies have indicated that at least some neuroendocrine skin carcinomas could in fact coexpress both aforementioned classes of intermediate filament proteins. This brief report is presented to confirm the latter investigations.

Carcinoma↗

Response of monkey glabrous skin mechanoreceptors to random-noise sequences: I. Temporal response characteristics.

The response of slowly adapting (SA, Merkel cell), rapidly adapting (RA, Meissner), and Pacinian corpuscle (PC) mechanoreceptors in monkey glabrous skin were recorded while being activated with a vibrotactile indenting stimulus. For one set of experiments, the stimulator was driven by an 800-point (400-msec) pseudorandom-noise (PRN) sequence, repeated 40 times. For a second set of experiments, a non-repeating-noise (NRN) sequence was used. SA impulse patterns generated with the PRN sequence were highly regular and similar for all afferents tested. RA and PC response patterns were more varied, but exhibited basic intraclass similarities. SA and RA PRN stimulus impulse patterns were often nearly indistinguishable at low to medium discharge rates. At higher discharge rates, RA and SA discharge patterns differed, primarily because of the unambiguous suprathreshold velocity sensitivity and shorter recovery periods of RA afferents. PC impulse patterns were substantially different from SA and RA patterns, being clearly dependent on the stimulus velocity at all stimulus intensities. Input-output correlation analysis, coupled with PRN stimulus-response analysis, provided a basis for hypothesizing the basic dynamic encoder function of each type of mechanoreceptor.

Afferent Pathways↗

[Intra-ventricular pressure gradient and systolic anterior movement of the mitral valve associated with administration of dopamine in a 91-year-old patient].

A 91-year-old woman had decreased systemic blood pressure accompanied by dyspnea and general fatigue after resection of a face tumor (Merkel cell carcinoma). Dopamine was administered to elevate systemic blood pressure, but it did not sufficiently restore the hemodynamic status. Left ventricular apical aneurysm was observed on echocardiogram. Furthermore, SAM (systolic anterior movement of the mitral valve) was observed on M-mode echocardiogram and a pressure gradient of 34.6 mmHg in the midventricular position was confirmed by continuous wave Doppler using the Bernoulli equation. After volume overload and discontinuation of dopamine, SAM completely disappeared and midventricular pressure gradient markedly decreased. Her general condition improved. Because of the narrowed outflow tract, hypercontractile state induced by beta adrenergic stimulation seemed to be one of the important factors for the genesis of SAM and pressure gradient.

Aged↗

Learning curves and certification for breast cancer lymphatic mapping.

To determine the usefulness of lymphatic mapping and SLN biopsy, two distinct aspects of the technique must be evaluated, mapping success rates and mapping accuracy. The mapping success rate simply reflects the ability to successfully map a SLN. Mapping accuracy is reflected by the false-negative rate defined as the proportion of patients with axillary metastases among those in whom the SLN is negative for disease. It is critical within each institution that these two measurements be obtained to validate the multidisciplinary collaborative effort. It seems that surgeons with appropriate training should be able to map with 85% efficiency with zero or one false-negative cases in their first 10 patients with metastatic disease. It is our recommendation that individual surgeons join together and follow an institutional (IRB approved) protocol for lymphatic mapping in which each surgeon is required to perform at least 30 procedures of SLN biopsy followed by completion axillary lymph node dissections (phase I). There are several advantages for surgeons and patients to participate in national trials as a new technique is established: 1. Patients are fully informed. 2. For those patients who have SLN biopsy followed by a CLND (phase I), there is still an added advantage in that the SLN can be scrutinized more closely resulting in more accurate staging. 3. The surgeon and the institution can be reimbursed even while the surgeon is on the learning curve. 4. It provides for good publicity for the institution. The data should be reviewed for each surgeon after completing the first 30 cases. If the aforementioned goals of 85% success with one or fewer false-negative cases is achieved, then the individual surgeon may move on to a second (phase II) mapping protocol. In phase II, a SLN biopsy is performed and a CLND is performed only if a SLN cannot be located or the SLN contains metastases. Should the aforementioned criteria not be met, then additional procedures or onsite intraoperative mentoring may be required to further evaluate the deficiencies of the mapping procedure by the surgeon or institution. Remember that failure to map may be a function of surgical skill, nuclear medicine injection methodology, or the pathologic evaluation of the SLN. Should institutional problems arise, onsite mentoring may be helpful by someone with adequate mentoring skills to troubleshoot a potential problem. The previously outlined recommendations are similar to the recently published requirements of the American Society of Breast Surgeons that recommend documentation of 30 cases or more with an 85% or higher success rate in identifying a SLN and 5% or greater false-negative rate (single false-negative SLN in the series). A national network of training centers is being established for radioguided surgery. This new technology has the potential of being applicable to 350,000 new cases of cancer diagnosed annually in the United States. Applications include breast cancer, melanoma, and other skin tumors like Merkel cell carcinoma and poorly differentiated squamous cell carcinoma, parathyroid localization, vulvar and vaginal lesions, and bone localization. This network of training centers will provide an opportunity for surgeons, nuclear medicine physicians, and pathologists to come together and learn about this new technology. Training will include didactic sessions, live surgery, and hands-on experience with animal models. The faculty will consist of leading experts from across the country. Participating centers include the H. Lee Moffitt Cancer Center and Research Institute, John Wayne Cancer Institute, and the M.D. Anderson Cancer Center. Training sites will also be available in Durham, NC; Pittsburgh, PA; Seattle, WA; Little Rock, AR; and St. Louis, MO. The network provides access to a national lymphatic mapping database (http:/(/)mapping.rad.usf.edu), participation in national trials, and web site listings (melanoma.net, or breastdoctor.com, and endocrine

Axilla↗

Observations on the structural and innervation of the rat snout.

Light and electron miscroscopy were employed to study the structure and innervation of the rat snout. The hairless skin at the tip of the snout was covered in epidermal ridges similar to the ridges seen on primate finger skin. Three types of nerve ending were observed in relation to the surface of snout: corpuscular, found in dermal papillae between epidermal rete ridges: hederiform, found in relation to Merkel cells at the base of the rete ridges; and free, which entered the epidermis from the sides and top of the dermal papillae. The evidence suggests that there may be two ultrastructurally distinct intraepidermal nerve fibres.

Animals↗

Fragile histidine triad gene and skin cancer.

Five years ago the fragile histidine triad (FHIT) gene including the most common fragile site locus of the human genome, FRA3B, was identified. The gene is altered in many types of cancer and several data support the idea that FHIT has to be considered a tumor suppressor. FHIT abnormalities were investigated in some skin tumors. Fifty-seven per cent of Merkel cell carcinomas displayed abnormal FHIT products but the involvement of FHIT in human non-melanoma skin cancer is still unclear. Because the murine Fhit locus is similar to its human homologue and is altered in cancer cell lines, we have established a strain of Fhit-deficient mice. After N-nitrosomethylbenzylamine treatment, the spectrum of tumors developed by the Fhit-deficient mice was similar to those observed in a familial skin cancer condition, the Muir-Torre syndrome, although there is no clear evidence yet for a relationship of FHIT and the human syndrome. Because cancer cells lacking in FHIT are defective in apoptosis, we propose the Fhit-deficient mouse as a model to understand a possible proapoptotic mechanism deficiency in the human syndrome.

Acid Anhydride Hydrolases↗

[CK20 expression in the gastrointestinal tract of the embryo and fetus].

A novel type of cytokeratin, cytokeratin 20 (CK20), was added in 1990 to the classic catalog of human cytokeratins, a heterogeneous group of proteins present in almost all epithelia. In man, the expression of CK20 is almost entirely confined to the gastro-intestinal epithelium, to the urothelium and to Merkel cells. Since only few data are available regarding the expression of CK20 in the developing human intestinal mucosa, we studied CK20 immunoreactivity in fetal and neonatal human gut. Immunoreactivity for CK20 was tested in fetuses and newborns, from the twelfth up to the fortieth week of gestation. In each subject, a specimen from the oesophagus, stomach, small intestine, colon, appendix was studied. Tissue samples were routinely processed and paraffin sections were stained with the CK20-specific antibody IT-Ks 20.8. CK20 immunoreactivity was absent in the oesophageal epithelium and it was unevenly distributed in the gastrointestinal mucosa. Three main patterns of immunoreactivity were observed during normal development: the first, found in the stomach and in the small bowel, is characterized by a progressive increase in CK20 expression during gestation; the second pattern, found in the duodenum, shows a progressive decrease in CK20 expression during gestation; in colon and appendix (third pattern), we did not find significant changes in the degree of immunoreactivity for CK20 during gestation. CK20 is unevenly expressed in developing human intestinal mucosa. The degree of positivity for CK20 appears to be related to the epithelial maturation stage only in gastric and small bowel mucosa. Further studies are needed to verify if the uneven CK20 immunoreactivity in the gastrointestinal tract persists even in adulthood.

Biomarkers↗

The morphology and innervation of facial vibrissae in the tammar wallaby, Macropus eugenii.

The morphology of the vibrissal follicles on the mystacial pad of the tammar wallaby is similar to that seen in other species except that the follicles lack a ringwulst or ring sinus. Instead, the mesenchymal sheath is thickened around the central region of the hair shaft. The follicle is innervated by both deep and superficial vibrissal nerves. The deep nerve enters as 4-11 fascicles which can be in close proximity or widely distributed around the hair. C1 follicles received more myelinated nerve fibres (252 +/- 31) than the smaller C4 follicles (174 +/- 43). The deep vibrissal nerve supplies the thickened mesenchymal sheath, the narrow 'waist' region above and the majority of endings in the inner conical body (ICB), while the superficial nerves provide a sparse innervation to the ICB and rete ridge. Receptors present in the follicle were of 4 types: (1) Merkel cells, especially numerous in the outer root sheath of the 'waist' region and occasionally in the ICB and rete ridge; (2) and (3) lanceolate and lamellated endings parallel to the hair shaft in both the mesenchymal thickening and the 'waist' region where they were particularly dense; (4) free nerve endings in the mesenchymal thickening, 'waist' region and ICB. No corpuscular, bulbous or Ruffini endings were seen. The innervation of the intervibrissal fur was similar to that described in other species.

Animals↗

[Cytokeratins--survey of incidence in normal and diseased skin. II. Cytokeratin expression in diseased skin].

The distribution patterns of cytokeratins demonstrated by different authors in benign and malignant tumours of the skin are presented and the resulting possibilities for histological differentiation are discussed. The monoclonal antibody A53-B/A2 made in GDR may be useful in the diagnosis of Merkel cell tumours or of the extramammary Morbus Paget. -For different dermatoses, especially some disease with abnormal types of keratinization, the expressed polypeptides are described.

Biomarkers, Tumor↗

[Anatomo-pathology of cholesteatoma].

The authors, from their own histopathological studies and from an overview of otological literature focus the controversial problems about the so-called disease cholesteatoma. The history of cholesteatoma has been marked out by pathologic data which, initially caused the cholesteatoma to be identified as a keratinized squamous tumor. This misnomer will however be retained because of it long-established usage. "Skin in the wrong place" in the middle ear summarizes this clinical entity. Electron microscopic observations provide arguments in favour of the migratory theory and the invasion of the epidermis from the bottom of the external ear canal into the middle ear cavity (identical fine morphology between skin and cholesteatoma, presence of Langerhans and Merkel cells, sharp junction between the advancing front of the cholesteatoma and the middle ear mucosa). Recent immunohistological techniques allow consideration of cholesteatoma as a self-induced inflammatory process in response to tissular and cellular conflicts. A cholesteatoma could be merely a non-healing wound process and a disease of epidermal growth control occurring in the middle ear space. The logical principles governing cholesteatoma surgery, suggested by these biological considerations, are: total removal of cholesteatoma matrix, prevention of cholesteatoma recurrence by a careful respect of the barrier separating the middle ear mucosa from the skin-lined bony external ear canal, maintenance of good healing conditions for both mucosa in a closed well-ventilated middle ear and epidermis in a harmonious anatomical external canal.

Cell Movement↗