Chapter 1: The Astrobiology Primer 3.0

The Astrobiology Primer 3.0 (ABP3.0) is a concise introduction to the field of astrobiology for students and others who are new to the field of astrobiology. It provides an entry into the broader materials in this supplementary issue of Astrobiology and an overview of the investigations and driving hypotheses that make up this interdisciplinary field. The content of this chapter was adapted from the other 10 articles in this supplementary issue and thus represents the contribution of all the authors who worked on these introductory articles. The content of this chapter is not exhaustive and represents the topics that the authors found to be the most important and compelling in a dynamic and changing field.

Chapter 8: Searching for Life Beyond Earth

The search for life beyond Earth necessitates a rigorous and comprehensive examination of biosignatures, the types of observable imprints that life produces. These imprints and our ability to detect them with advanced instrumentation hold the key to our understanding of the presence and abundance of life in the universe. Biosignatures are the chemical or physical features associated with past or present life and may include the distribution of elements and molecules, alone or in combination, as well as changes in structural components or physical processes that would be distinct from an abiotic background. The scientific and technical strategies used to search for life on other planets include those that can be conducted in situ to planetary bodies and those that could be observed remotely. This chapter discusses numerous strategies that can be employed to look for biosignatures directly on other planetary bodies using robotic exploration including those that have been deployed to other planetary bodies, are currently being developed for flight, or will become a critical technology on future missions. Search strategies for remote observations using current and planned ground-based and space-based telescopes are also described. Evidence from spectral absorption, emission, or transmission features can be used to search for remote biosignatures and technosignatures. Improving our understanding of biosignatures, their production, transformation, and preservation on Earth can enhance our search efforts to detect life on other planets.

Brillouin scattering for refractive index sensing in non-adiabatic tapers

We demonstrate the use of non-adiabatic tapers for refractive index sensing in optical fibers based on Brillouin scattering. By exciting higher order optical modes along the taper, the Brillouin gain spectrum becomes multipeaked, where each peak exhibits a different sensitivity to the refractive index of the surrounding medium. By this method, we demonstrate a sensitivity enhancement of the Brillouin frequency shift to refractive index changes by a factor of ≈ 4, compared to an adiabatic taper with the same waist diameter. Furthermore, the use of the spectral difference between two Brillouin gain peaks provides a temperature-independent measurement of the external refractive index.

Graphene Oxide and Reduced Graphene Oxide Nanoflakes Coated with Glycol Chitosan, Propylene Glycol Alginate, and Polydopamine: Characterization and Cytotoxicity in Human Chondrocytes

Recently, graphene and its derivatives have been extensively investigated for their interesting properties in many biomedical fields, including tissue engineering and regenerative medicine. Nonetheless, graphene oxide (GO) and reduced GO (rGO) are still under investigation for improving their dispersibility in aqueous solutions and their safety in different cell types. This work explores the interaction of GO and rGO with different polymeric dispersants, such as glycol chitosan (GC), propylene glycol alginate (PGA), and polydopamine (PDA), and their effects on human chondrocytes. GO was synthesized using Hummer's method, followed by a sonication-assisted liquid-phase exfoliation (LPE) process, drying, and thermal reduction to obtain rGO. The flakes of GO and rGO exhibited an average lateral size of 8.8 ± 4.6 and 18.3 ± 8.5 µm, respectively. Their dispersibility and colloidal stability were investigated in the presence of the polymeric surfactants, resulting in an improvement in the suspension stability in terms of average size and polydispersity index over 1 h, in particular for PDA. Furthermore, cytotoxic effects induced by coated and uncoated GO and rGO on human chondrocytes at different concentrations (12.5, 25, 50 and 100 µg/mL) were assessed through LDH assay. Results showed a concentration-dependent response, and the presence of PGA contributed to statistically decreasing the difference in the LDH activity with respect to the control. These results open the way to a potentially safer use of these nanomaterials in the fields of cartilage tissue engineering and regenerative medicine.

Hybrid Brillouin/Rayleigh sensor for multiparameter measurements in optical fibers

We present a hybrid Brillouin/Rayleigh sensor for multiparameter sensing in optical fibers. The system makes use of a single laser pulse to excite both Rayleigh and Brillouin backscattering in the same optical fiber. In the detection path, the backscattered signals are separated based on their different wavelengths. The system is capable of determining simultaneously the Brillouin frequency shift (BFS) of the fiber, as well as the frequency contents of any vibration acting on the same fiber as recovered by phase sensitive OTDR (ϕ-OTDR) measurements. The reported experiments show the possibility to perform simultaneous temperature and vibration measurements, as well as to perform dynamic strain measurements combining the information provided by slope-assisted Brillouin scattering measurements, with those provided by amplitude-based ϕ-OTDR measurements.

Theoretical and experimental comparison of a distributed acoustic sensor at 850- and 1550-nm wavelengths

In this paper, we analyze the performance of a distributed acoustic sensor at two different interrogation wavelengths. We show theoretically that, in a coherent optical time-domain reflectometry (OTDR) operating at 850 nm, the dynamic signal-to-noise ratio (SNR) is enhanced, compared to an identical configuration operating at 1550 nm. Such enhancement is maximum at the interrogating pulse input section, while decreasing along the fiber in virtue of the higher loss. Experimental tests, carried out using two heterodyne C-OTDR detection schemes operating at the analyzed wavelengths, confirm the SNR improvement.

Screening of the chemical composition and bioactivity of Waldheimia glabra (Decne.) Regel essential oil

BACKGROUND

This research aimed at improving knowledge as to the chemical composition and the antibacterial and anti-cancer activities of the essential oil of Waldheimia glabra, a wild plant from the Himalayan Mountains.

RESULTS

The results obtained by GC-MS showed that spathulenol, 9-tetradecenol, thujopsene, α-thujone, santolina alcohol and terpinen-4-ol were the main constituents of Waldheimia glabra essential oil. These results were confirmed by HS-SPME GC-MS analysis that also reported high amounts of artemisia alcohol and camphor. Disc diffusion assay suggested a mild antibacterial activity against both Escherichia coli and Staphylococcus aureus. Finally, a dose-response correlation was observed between Waldhemia glabra essential oil concentration and viability of human breast adenocarcinoma cells MDA-MB-231 and MCF-7.

CONCLUSIONS

Together with the GC-MS method, HS-SPME GC-MS proved to be a reliable technique to characterise the chemical composition of essential oil obtained from aromatic plants. Further studies will focus on W. glabra phytochemicals and their biological activity, in order to support traditional uses of the plant. © 2015 Society of Chemical Industry.

Tissue-engineered skin substitutes: an overview

Extensive skin loss and chronic wounds are still a significant challenge to clinicians: even if injured epidermis is normally able to self-renew, deep injuries can cause negative regulation of the wound healing cascade, leading to chronic wound formation. Skin-autografting surgical procedures are often limited by the poor availability of healthy tissue, whereas the use of non-self-tissues for allografts presents some severe risks. Tissue-engineered skin substitutes have recently become viable as a suitable alternative to auto- and allografts. However, biologists, biochemists, and technical engineers are still struggling to produce complex skin substitutes that can readily be transplanted in large quantities. The ambitious goal is now to construct a dermoepidermal substitute that rapidly vascularizes and optimally supports a stratifying epidermal graft on a biodegradable matrix. This review analyzes these aspects in light of the available literature and the authors' experience.

Adipose-derived adult stem cells: available technologies for potential clinical regenerative applications in dentistry

Tissue homeostasis depends closely on the activity and welfare of adult stem cells. These cells represent a promising tool for biomedical research since they can aid in treatment and promote the regeneration of damaged organs in many human disorders. Adult stem cells indefinitely preserve their ability to self-renew and differentiate into various phenotypes; this capacity could be promoted in vitro by particular culture conditions (differentiation media) or spontaneously induced in vivo by exploiting the biochemical and mechanical properties of the tissue in which the stem cells are implanted. Among the different sources of adult stem cells, adipose tissue is an attractive possibility thanks to its ready availability and the standard extraction techniques at our disposal today. This review discusses the isolation, characterization, and differentiation of human adipose-derived adult stem cells, as well as regeneration strategies, therapeutic uses, and adverse effects of their delivery. In particular, since oral disorders (e.g., trauma, erosion, and chronic periodontitis) often cause the loss of dental tissue along with functional, phonetic, and aesthetic impairment, this review focuses on the application of human adipose-derived adult stem cells, alone or in combination with biomaterials, in treating oral diseases.

Unspecific redness of the eyelid--two malignant tumours

BACKGROUND

Chronic, non- or little pigmented reddish or brownish lesions on the lid margin and the surrounding skin are frequently underestimated and thus carry a clear risk of malignancy.

HISTORY AND SIGNS

A 61-year-old lady was referred with a chronic, reddish lesion in the medial third of the left lower lid after a topical therapy over a period of 4 months had not improved the situation. She noticed the lesion for the first time 10 previously. Recurrent trichiasis and a slight ulceration had developed during the last year.

THERAPY AND OUTCOME

After an unclear result of the biopsy (2)/ (3) of the left lower lid were removed because of atypical cells ascending into the epidermis. A superficial spreading melanoma 0.4 mm depth in the Breslow classification was detected and right next to it a superficial basal cell carcinoma. The lid defect was reconstructed with a tarsoconjunctival flap and a free full thickness skin graft as described by Hughes.

CONCLUSION

Chronic redness at or around the lid margin which does not respond to therapy should be biopsied as malignant tumours may well be hidden behind it.

The effects of chronic exercise on anesthesia induced hepatotoxicity

A hypoxic rat model of halothane-induced hepatotoxicity, which is known to produce liver damage, was used to determine the effects of chronic exercise on halothane-induced hepatotoxicity and on reduced hepatic glutathione (GSH) levels. Metabolism of volatile anesthetics may generate metabolites that can cause mild and transient hepatotoxicity.

METHODS

Six male Sprague-Dawley rats completed a 10-wk (5 d x wk(-1)) treadmill running protocol. Twelve age-matched animals were used as sedentary controls. After the completion of exercise training, rats were exposed for 2 h to 1% halothane in 14% O2. Twenty-four hours later, animals were anesthetized with sodium pentobarbital and sacrificed. Livers were excised, stained, and evaluated for hepatotoxicity using a histopathological 0 (normal) to 5 (severe damage) point categorical scale and for the determination of GSH levels.

RESULTS

Median histopathologic scores revealed significantly lower indications of hepatotoxicity in exercise animals as compared with control animals (score = 0.25 vs 1.50; P < 0.05). Liver damages scores between 1 and 5 were observed in 75% (9 of 12) of the control animals, whereas only 1 of 6 exercise animals had a score greater than 1 (P < 0.05). No significant difference was observed in reduced GSH levels.

CONCLUSIONS

Chronic exercise improves the detoxicant ability of the liver for halothane anesthesia as noted by the ameliorated liver damage and reduced incidence of halothane-induced hepatotoxicity in the exercise animals.

Characterization of an antibody that can detect an activated IGF-I receptor in human cancers

The type 1 insulin-like growth factor receptor (IGF-IR) plays an important role in malignant transformation and in apoptosis. Its role in human cancer has now been firmly established. IGF-IR signaling occurs only when the receptor is activated by its ligands, which induce autophosphorylation of the receptor at several tyrosine residues. Although the IGF-IR (phosphorylated or not) can be detected in human cancers with conventional antibodies, it would be desirable to obtain antibodies that can detect the IGF-IR only when activated by its ligands. We describe and characterize in this paper such an antibody and show that it can be used in sections of human cancers to detect an autophosphorylated IGF-IR. This antibody will be useful in detecting autocrine or paracrine influences on normal and tumor cells and could eventually be also useful in diagnostic and prognostic studies of human primary and metastatic cancer.

Superior mesenteric arterial occlusion from a leiomyoma

We report a solitary leiomyoma of the superior mesenteric artery resulting in arterial occlusion and gangrenous bowel. On histologic evaluation the lesion extended into the vessel lumen off its stalk and showed immunostaining for smooth muscle antigen and desmin. Leiomyomas can arise anywhere there is smooth muscle and occur most commonly in the uterus followed by the skin and gastrointestinal tract. We could not identify any previous case in the literature of a leiomyoma arising from within the wall of a mesenteric vessel.

The cardiopulmonary, eicosanoid, and tissue microanatomic effects of fluconazole during graded bacteremia

Imidazole compounds have been shown to be beneficial in systemic sepsis and inflammation. The purpose of this study was to delineate the effects of fluconazole on systemic hemodynamics and on microanatomy of the heart, lung, liver, and kidney parenchyma of swine during graded bacteremia. Eighteen adult swine were studied in three groups: 1), anesthesia control; 2), septic control (Aeromonas hydrophila, 10(9)/mL, infused i.v. for 4 h); 3) fluconazole (fluconazole, 30 mg/kg i.v., followed by A. hydrophila infusion). After 4 h of graded bacteremia, autopsy was performed. Compared with the septic control group, cardiac index, oxygen delivery, and oxygen consumption were reduced significantly after fluconazole pretreatment, and mixed venous hemoglobin oxygen saturation (SVO2) and oxygen extraction were increased. Plasma thromboxane A2 and leukotriene levels were not affected by fluconazole. Computerized digital image analysis of the liver, heart, and kidney specimens revealed no statistically significant differences between the septic control group and fluconazole-pretreated animals. In the lung specimens, preinfusion of fluconazole decreased alveolar wall thickness in septic swine (anesthesia control group: 8.15 x 10(-3) +/- 1.3 x 10(-3)mm versus septic control group: 9.9 x 10(-3) +/- 1.3 x 10(-4) versus fluconazole group: 6.8 x 10(-3) +/- 1.6 x 10(-3); p < or = .05). Fluconazole pretreatment before graded bacteremia has no beneficial effect on cardiopulmonary performance or septic tissue edema of the heart, kidney, or liver. Tissue oxygen metabolism might be down-regulated by fluconazole. However, preinfusion of fluconazole appears to normalize the sepsis-induced increase in pulmonary alveolar wall thickness. The net significance of these changes on clinical outcome is not clear from these data.

Method to make paraffin-embedded breast and lymph tissue mimic fresh tissue in DNA analysis

Determination of DNA ploidy has been found to be of diagnostic and prognostic value with regard to many solid tumors. Flow cytometric analysis of DNA ploidy is dependent on the binding of fluorescent dyes to DNA. Preserving cell morphology by fixing the tissue in formalin interferes with the binding of propidium iodide (PI) and other fluorescent dyes to DNA. This distortion of DNA content measurement can cause inaccuracies in DNA-ploidy determinations of formalin-fixed tissue specimens and precludes the use of appropriate DNA standards. Therefore, it has been impossible to determine accurately the DNA ploidy of formalin-fixed, paraffin-embedded (FFPE) tissues. Using formalin-fixed cells as a model for FFPE cells, we developed a thermal treatment method to reverse the effect of formalin on the binding of propidium iodide to DNA. Applying this approach to the preparation of FFPE lymph node and breast tissue for DNA analysis, we have developed a method that makes the binding of PI to the DNA of FFPE tissue mimic that of fresh tissue. Following dewaxing, rehydration, and trypsin treatment, the FFPE tissue, resuspended in PBS, was heated to 75 degrees C for 90 min to restore the PI binding to that of fresh cells. This method makes it possible to use fresh, DNA-diploid cells as an internal control and, thus, determine more accurately the DNA ploidy of tumors preserved in formalin and paraffin.

Detection and monitoring of a concomitant atypical myeloproliferative disorder and chronic lymphocytic leukemia by flow-cytometric immunophenotyping

OBJECTIVE

To illustrate the utility of a broad panel of monoclonal antibodies to detect secondary processes or unexpected characteristics of the primary blood dyscrasia.

DESIGN

Case report and discussion.

SETTING

Regional academic medical center.

PATIENT

A 64-year-old man presenting with an apparent acute myeloid leukemia.

INTERVENTIONS

Sequential immunophenotyping with a broad panel of monoclonal antibodies to monitor progression of disease and response to therapy.

MAIN OUTCOME MEASURE

Identification and monitoring of the two atypical populations in this patient with correlation to the clinical status of the patient.

RESULTS

Identification of an unsuspected mature lymphoid clone and characterization of the evolution of the myelomonocytic clone.

CONCLUSION

The evolving mature lymphoid clone may have been overlooked in the context of a predominant atypical myeloproliferative process, particularly if a limited panel of monoclonal antibodies had been used for immunophenotyping. Sequential immunophenotyping was useful in monitoring the progression of each atypical process.

Invasive colitis and hepatitis due to previously uncharacterized spirochetes in patients with advanced human immunodeficiency virus infection

We describe three patients with advanced human immunodeficiency virus (HIV) infection, two with colitis and one with cholestatic hepatitis, for whom results of detailed endoscopic and histologic studies were suggestive of invasive spirochetosis. In the two patients with colitis, colonoscopic evaluation revealed either diffuse ulcerations or pustules; in both cases, there was histologic evidence of extensive superficial cell necrosis and infiltration of the mucosa and lamina propria with acute inflammatory cells. Spirochetes in the mucosa and crypts were visualized by Warthin-Starry silver staining. Morphologically similar spirochetes throughout the liver specimen from the patient with cholestatic hepatitis were demonstrated by Warthin-Starry silver staining. Analysis with electron microscopy revealed these organisms to be loosely coiled spirochetes. Despite extensive evaluation, no other pathogens were identified. Invasive spirochetal infection, as defined by the results of Warthin-Starry silver staining of involved tissues, should be considered in the differential diagnosis of patients with HIV infection who have otherwise unexplained colitis or cholestatic hepatitis.

[Torsion of testicular appendages: a case of acute scrotum due to torsion of the hydatid of Morgagni]

The torsion of testicular appendages is the most frequent cause of acute scrotum in pediatric patients. The Authors report a case of Morgagni's hydatid torsion and stress that surgical exploration is the best therapeutical choice whenever the etiological diagnosis is uncertain.

[Cervicofacial neuroendocrine Merkel cell carcinoma: radiotherapy]

The Authors report a case of Merkel cell carcinoma of the cervicofacial district, particular due to its clinical and evolutive characteristics. The Merkel cell carcinoma was first identified by Toker in 1972 and is also known as a primary neuroendocrine the or trabecular carcinoma of the skin. The Merkel cell carcinoma is a rare aggressive skin cancer most frequently localized in the cervicofacial district. Although in earlier reports on the clinical history of these tumors primary emphasis was placed on their local aggressive behaviour, it has recently become evident that these neoplasms have a marked propensity for early dissemination. Distant metastases are often responsible for disease-related mortality. Merkel cell carcinoma have classically been managed with surgery alone or surgery followed by radiation therapy. Treatment of Merkel cell carcinoma with radiation therapy alone has usually been reserved for advanced unresectable tumors.

Basaloid squamous cell carcinoma of floor of mouth

BACKGROUND

Only five cases of basaloid squamous cell carcinoma (BSCC), a rare tumor of head and neck, have been reported to involve the floor of mouth.

METHODS

Clinicopathologic and immunohistochemical features of eight BSCC of floor of mouth were studied to evaluate the significance of the basaloid features.

RESULTS

Five patients were male and three were female. Their mean age was 52 years (range, 39-59). At presentation, one patient was diagnosed with Stage II disease, four were diagnosed with Stage III disease, and three were diagnosed with Stage IV disease. Aside from typical squamous differentiation, each patient had a component of basaloid cells arranged in irregular nests, cords, or pseudoglandular spaces with a brisk mitotic rate, myxoid stroma, and marked tendency for perineural invasion. A panel of immunostains yielded the following results: keratin, +8/8; carcinoembryonic antigen, +3/8; and S-100, chromogranin, and neuron-specific enolase were negative. Mucin stains were negative in all cases. Ultrastructural characterization of three BSCC revealed squamous differentiation of the basaloid cells and a peculiar basal membrane-like material in between them. No neurosecretory granules were present. Seven patients underwent surgery; six of them were also treated with postoperative radiation therapy. In two cases, chemotherapy was added at recurrence. One nonresectable patient received radiation and chemotherapy. At the last follow-up, five patients were dead of disease within 13 months from the diagnosis. One patient died of an unknown cause. Two patients were still alive at the time of this report, 4 and 2 months after treatment. Seven patients had recurrent disease. The authors compared these data with a control group of patients with conventional squamous cell carcinoma (SCC).

CONCLUSIONS

The authors' results indicate that BSCC of floor of mouth is an aggressive variant of SCC and is prognostically worse than the conventional SCC, regardless of the grade of the latter.