Mars Extant Life: What's Next? Conference Report.

On November 5-8, 2019, the "Mars Extant Life: What's Next?" conference was convened in Carlsbad, New Mexico. The conference gathered a community of actively publishing experts in disciplines related to habitability and astrobiology. Primary conclusions are as follows: A significant subset of conference attendees concluded that there is a realistic possibility that Mars hosts indigenous microbial life. A powerful theme that permeated the conference is that the key to the search for martian extant life lies in identifying and exploring refugia ("oases"), where conditions are either permanently or episodically significantly more hospitable than average. Based on our existing knowledge of Mars, conference participants highlighted four potential martian refugium (not listed in priority order): Caves, Deep Subsurface, Ices, and Salts. The conference group did not attempt to reach a consensus prioritization of these candidate environments, but instead felt that a defensible prioritization would require a future competitive process. Within the context of these candidate environments, we identified a variety of geological search strategies that could narrow the search space. Additionally, we summarized a number of measurement techniques that could be used to detect evidence of extant life (if present). Again, it was not within the scope of the conference to prioritize these measurement techniques-that is best left for the competitive process. We specifically note that the number and sensitivity of detection methods that could be implemented if samples were returned to Earth greatly exceed the methodologies that could be used at Mars. Finally, important lessons to guide extant life search processes can be derived both from experiments carried out in terrestrial laboratories and analog field sites and from theoretical modeling.

Fibrinogen concentrates for bleeding trauma patients: what is the evidence?

INTRODUCTION: A balanced transfusion of red blood cells, fresh frozen plasma and platelets are recommended for massively bleeding trauma patients. Fibrinogen concentrates could potentially lessen or replace the need for fresh frozen plasma and/or platelet transfusions. OBJECTIVE: To provide a review of the literature covering the application of fibrinogen concentrates in trauma care. METHODS: PubMed and Cochrane database search, 'fibrinogen' and ('concentrate' or 'trauma'), not 'congenital', 10 years. RESULTS: Only four papers were identified. None were randomized controlled trials. The main conclusion of these papers was that administration of fibrinogen sometimes together with prothrombin complex concentrate might improve haemostasis in trauma patients resuscitated with synthetic colloids. CONCLUSION: Evidence for the use of fibrinogen concentrate to trauma patients with massive bleeding is lacking. Well-designed prospective, randomized, double-blinded studies evaluating the effect of fibrinogen concentrate, as the only intervention, are urgently needed.

In vitro transactivation of Bacillus subtilis RNase P RNA.

Deletion of the 'signature' PL5.1 stem-loop structure of a Type II RNase P RNA diminished its catalytic activity. Addition of PL5.1 in trans increased catalytic efficiency (kcat/KM) rather than kcat. Transactivation was due to the binding of a single PL5.1 species per ribozyme with an apparent Kd near 600 nM. The results are consistent with the role of PL5.1 being to position the substrate near the active site of the ribozyme, and with the hypothesis that ribozymes can evolve by accretion of preformed smaller structures.

Origin and radiation of Southern Hemisphere coastal dolphins (genus Cephalorhynchus).

The genus Cephalorhynchus (Gray 1846) consists of four species of small coastal dolphins distributed in cool temperate waters around the Southern Hemisphere. Each species is sympatric with other members of the subfamily Lissodelphininae but widely separated from other congeners. To describe the origin and radiation of these species, we examined 442 bp of mitochondrial DNA control region sequences of 307 individuals from the genus Cephalorhynchus and compared these to sequences from other members of the subfamily Lissodelphininae. We investigate the hypotheses that Cephalorhynchus is a monophyletic genus or, alternatively, that the four species have arisen separately from pelagic Lissodelphine species and have converged morphologically. Our results support the monophyly of Cephalorhynchus within the Lissodelphininae and a pattern of radiation by colonization. We confirm a pattern of shallow but diagnosable species clades with Heaviside's dolphin as the basal branch. We further examine the monophyly of maternal haplotypes represented by our large population sample for each species. Based on this phylogeographic pattern, we propose that Cephalorhynchus originated in the waters of South Africa and, following the West Wind Drift, colonized New Zealand and then South America. The Chilean and Commerson's dolphins then speciated along the two coasts of South America, during the glaciation of Tierra del Fuego. Secondary radiations resulted in genetically isolated populations for both the Kerguelen Island Commerson's dolphin and the North Island Hector's dolphin. Our results suggest that coastal, depth-limited odontocetes are prone to population fragmentation, isolation and occasionally long-distance movements, perhaps following periods of climatic change.

School-based health centers as a locus for community health improvement.

School-based health centers are critical resources for providing and coordinating health and medical services for children and adolescents. As such, they are an increasingly important component in a strategy to meet the comprehensive health, social, and educational needs of students and families. We show how educators and health professionals, using the language, methods and principles of continuous improvement, can collaborate effectively in addressing the specific concerns of school attendance and teen smoking.

Temporal lobe epilepsy presenting as panic attacks: detection of interictal hypometabolism with positron emission tomography.

Cerebral glucose metabolism was studied using positron emission tomography (PET) in a 13-year-old girl with a history of panic attacks that were thought to be of psychiatric origin. Positron emission tomography imaging revealed marked right temporal lobe hypometabolism and magnetic resonance imaging (MRI) detected T2 changes consistent with right mesial temporal sclerosis. Electroencephalogram (EEG) studies 3 years later confirmed a primary diagnosis of right temporal lobe epilepsy. As shown by this case and one other, PET and MRI imaging of patients with panic disorder who are thought to have epilepsy may be helpful in leading to definitive electrographic studies that confirm temporal lobe epilepsy as the primary diagnosis.

Reduced F-18 fluorodeoxyglucose uptake within marrow after external beam radiation.

PURPOSE: The authors examined the delayed effects of external beam radiation on the metabolism of intravertebral marrow cavities. MATERIALS AND METHODS: Two neurologically normal persons who had completed a full course of external beam radiotherapy for squamous cell carcinoma of the head and neck had positron emission tomography (PET) scans with F-18 fluorodeoxyglucose (FDG) to identify residual neoplasm. RESULTS: Abnormally low uptake of F-18 FDG was noted within the central marrow cavities of the cervical vertebral bodies in both cases. CONCLUSIONS: Diminished metabolic activity within irradiated marrow can be revealed by F-18 FDG PET imaging techniques. Further correlative MRI PET studies are needed to determine if this postradiation phenomenon is related to fatty infiltration of the marrow cavity.

Palatal myoclonus secondary to vertebral artery compression of the inferior olive.

A 47-year-old male with a 5-year history of palatal myoclonus was found on magnetic resonance imaging (MRI) examination to have an ectatic dominant left vertebral artery that compressed the left inferior olive. Microvascular decompression effectively eliminated his symptoms. This case and a similar case presented here with an ectatic vertebral-basilar system illustrate the value of standard MRI in conjunction with magnetic resonance angiography (MRA) in evaluating palatal myoclonus, and they suggest a potential role for decompressive surgery when persistent, highly symptomatic inferior olivary ischemia or compression occurs.

Gross and microscopic visceral anatomy of the male Cape fur seal, Arctocephalus pusillus pusillus (Pinnipedia: Otariidae), with reference to organ size and growth.

The gross and microscopic anatomy of the Cape fur seal heart, lung, liver, spleen, stomach, intestine and kidneys (n = 31 seals) is described. Absolute and relative size of organs from 30 male seals are presented, with histological examination conducted on 7 animals. The relationship between log body weight, log organ weight and age was investigated using linear regression. Twenty five animals were of known age, while 6 were aged from counts of incremental lines observed in the dentine of tooth sections. For the range of ages represented in this study, body weight changes were accurately described by the exponential growth equation, weight = w(o)r(t), with body weight increasing by 23 % per annum until at least 9-10 y of age. Organ weight increased at a rate of between 25 % and 33 % per annum until at least 9-10 y of age, with the exception of the intestines, where exponential increase appeared to have ceased by about 7 y. The relationship between body weight and organ weight was investigated using logarithmic transformations of the allometric equation, y = ax(b), where the exponent b is 1 if organ weight is proportional to body weight. Most organs increased in proportion to the body. However, the heart, liver and spleen had exponents b > 1, suggesting that these organs increased at a faster rate than the body. The basic anatomical features of the viscera were similar to those of other pinnipeds, with some exceptions, including the arrangement of the multilobed lung and liver. Apart from the large liver and kidneys, relative size of the organs did not differ greatly from similar sized terrestrial carnivores. The histological features of the organs were generally consistent with those previously described for this species and other otariids. The heart, as in other pinnipeds, was unlike that of cetacea in not having unusually thick endocardium or prominent Purkinje cells. Notable histological features of the lungs included prominent fibrous septa, prominent smooth muscle bundles, cartilage extending to the level of the alveolar sacs and ample lymphoid tissue. The spleen had a thick capsule, well developed trabeculae and plentiful plasma cells. Abundant parietal cells were present in the fundic glands and lymphoid follicles were present in the gastric lamina propria, particularly in the pyloric region. Small intestinal villi were very long but this could have resulted from underlying chronic inflammation. Lymphoid follicles were prominent in the colon. The kidney reniculi each had a complete cortex, medulla and calyx, but a sportaperi medullaris musculosa was not identified.

Transient blindness associated with reversible occipital white matter abnormalities: two patients studied by MR, CT, and 18F-FDG PET imaging.

Reversible, multifocal hyperintense T2 signal abnormalities were noted within the occipital and posterior parietal subcortical white matter in a previously healthy 59-year-old right-handed woman with acute onset of cortical blindness and seizures. Repeat brain magnetic resonance imaging and a positron emission tomographic scan of 18F-fluorodeoxyglucose brain uptake performed 2 months after the ictal event failed to reveal any abnormality. This patient is similar to a 57-year-old female who developed severe headache and magnetic resonance signal abnormalities in the subcortical white matter of both occipital lobes, which later normalized, as judged by correlative, sequential computed tomographic examinations. This study emphasizes that an increasingly more frequent phenomenon of reversible MRI signal abnormalities can occur within the occipital subcortical white matter in acutely ill individuals, and not be associated with any lasting abnormalities on clinical examination or on radiological imaging studies such as computed tomography, magnetic resonance imaging, or positron emission tomography.

Positron emission tomography in diagnosis of occult adenocarcinoma of the breast.

Occult adenocarcinoma with clinically apparent axillary lymphadenopathy represents a challenging surgical problem. Mammography is frequently unable to identify a primary breast carcinoma, and extramammary sources are common and equally difficult to identify. This may leave the clinician and patient with a conundrum of whether to proceed with "blind" mastectomy. A 35-year-old white female presented with axillary adenopathy and a normal breast physical exam. Mammography was unable to demonstrate a specific tumor. Excisional biopsy of the axillary lymph node demonstrated metastatic adenocarcinoma. Positron emission tomography showed increased uptake in the breast and the axilla, consistent with breast carcinoma and axillary metastases. The patient underwent modified radical mastectomy and pathologic review of the specimen proved infiltrating ductal carcinoma in the breast with metastatic nodes. Positron emission tomography may be helpful in localizing occult carcinoma of the breast that presents with metastatic lymph nodes and in excluding other potential primaries.

Delayed-onset expulsive choroidal hemorrhage following traumatic globe rupture.

The authors describe a 59-year-old woman who had a traumatic wound rupture 6 months following penetrating keratoplasty. While she was in the pre-operative holding area awaiting surgical repair, hemorrhagic choroidal detachments developed. Digital pressure was initiated on diagnosis of imminent expulsion of intraocular contents and maintained until repair of the wound rupture could be performed. Four months postoperatively, the patient's vision was 20/80 and her central pachymetry was 585 microns. This case demonstrates that a delayed-onset expulsive choroidal hemorrhage may be successfully managed with simple and rapid intervention based on knowledge of the disease process.

The effect of phacoemulsification on aqueous outflow facility.

OBJECTIVE: Although control of intraocular pressure (IOP) after cataract extraction may be of critical importance, little is known regarding changes in facility of outflow in the early postoperative period. The effect of phacoemulsification and conjunctival peritomy size on the coefficient of aqueous outflow facility (C) and IOP was studied. DESIGN: Participants were assigned randomly to one of two treatment groups. PARTICIPANTS: Seventy-four patients with cataract and without evidence of glaucoma were studied. INTERVENTION: Patients were randomized to receive either single- or two-quadrant conjunctival peritomy and phacoemulsification. MAIN OUTCOME MEASURES: Tonometry and tonography were assessed before surgery and at 1 day, 1 week, 6 weeks, and 1 year after surgery by a masked observer. RESULTS: Fifty patients with a mean of 11.4 months' (range, 10-13 months) follow-up were analyzed. Patients with reduced preoperative facility of outflow (as defined by C < or = 0.28 microliter/min/mmHg) showed a significant improvement from a mean preoperative value of 0.24 +/- 0.04 microliter/min/mmHg to 0.41 +/- 0.22 microliter/min/mmHg at 1 year (P = 0.002, N = 19). Among all patients, there was no significant change between mean preoperative C and last follow-up (0.39 +/- 0.23 vs. 0.46 +/- 0.38 microliter/min/mmHg, not significant [ns], N = 50). Furthermore, there was no significant change between mean preoperative and final IOP (23.7 +/- 4.1 vs. 23.3 +/- 3.9 mmHg, ns, N = 50). There was a significant elevation of mean IOP on postoperative day 1 to 27 +/- 6.2 mmHg (P = 0.001, N = 50). Patients with IOP elevations greater than 8 mmHg on postoperative day 1 had significantly elevated IOP at 1 year compared to preoperative values (P = 0.02, N = 12). There were no significant differences detected regarding C or IOP between single- or two-quadrant peritomy groups. CONCLUSIONS: Outflow facility improves after phacoemulsification in patients with a reduced preoperative coefficient of aqueous outflow. Postoperative day 1 IOP is significantly elevated after phacoemulsification. Conjunctival peritomy size does not appear to play a role in aqueous outflow facility or IOP after surgery.

Decreased multi-band posterior interhemispheric coherence with a lipoma on the corpus callosum: a case report of a possible association.

The corpus callosum plays a role in mediating interhemisphere communication. Coherence may be a quantitative EEG-based measure of this communication. The present report is of a female schizophrenic patient with a marked coherence deficit in the temporal-parietal-occipital region involving multiple frequency bands. An MRI scan of her brain revealed a lipoma involving the splenium of the corpus callosum. It is speculated that this lipoma may have caused a physical impingment on or developmental aberration of adjacent callosal fibers, resulting in the observed coherence deficit. Further studies of coherence measures in patients with collosal lipomas are proposed.

Bilateral peripheral ulcerative keratitis associated with pyoderma gangrenosum.

PURPOSE: A 37-year-old Hispanic man with a history of chronic myelogenous leukemia was first seen with fever and preseptal cellulitis of this right orbit after a tooth extraction. METHODS: The patient subsequently developed bilateral, severe peripheral ulcerative keratitis. He was treated with systemic antibiotics for a presumed underlying infectious cause. Several painful, necrotizing skin lesions developed over his face, trunk, and extremities. RESULTS: Repeated skin biopsies of the necrotizing lesions were consistent with pyoderma gangrenosum. Both the skin lesions and peripheral ulcerative keratitis responded dramatically to systemic prednisone. CONCLUSIONS: Pyoderma gangrenosum should be included in the differential diagnosis of peripheral ulcerative keratitis.