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.

Pharmacotherapy with botulinum toxin: harnessing nature's most potent neurotoxin.

Botulinum toxin (BTX), a potent biologic neurotoxin, commonly is associated with lethal outbreaks of food poisoning; however, it also plays a role as a therapeutic agent. Since the 1970s physicians have investigated BTX therapy in patients with neurologic disorders. The number of applications greatly expanded over the years to include certain focal dystonias (blepharospasm, torticollis, laryngeal dystonias, writer's cramp), strabismus, and a wide variety of other indications (gastrointestinal disorders, cosmetic wrinkle correction, spasticity, hyperhidrosis). BTX's safety and efficacy are reviewed.

Liver transplant in complete situs inversus: a case report.

BACKGROUND: Several technical solutions have been proposed for patients with situs inversus (SI) needing liver transplantation. This report describes the hepatic replacement in a patient with complete SI with dextrocardia. In the only other reported patient with complete SI the donor right lobe was placed over the vertebral column and the stomach to align the donor cava with that of the recipient. METHODS: A 45-year-old woman with complete SI, suffering from Laënnec's cirrhosis with frequent upper gastrointestinal hemorrhages, underwent transplantation in June 1991. The recipient weighed 48.2 kilograms and was 155 centimeters tall. The donor weighed 77.3 kilograms and was 188 centimeters tall. The weight of the native liver was 1934 grams, and the donor liver weighed 1595 grams. RESULTS: At hepatectomy of the native liver an intact vena cava was left behind. Donor liver was rotated 90 degrees to the left, making the donor left lobe point into the left iliac fossa and the donor right lobe fall into the recipient hepatic fossa. Donor infrahepatic vena cava was sewn end-to-side to the recipient vena cava. Suprahepatic vena cava was oversewn. Donor and recipient hila were well aligned, allowing a standard arterial reconstruction and a choledocholedochostomy. Patient's recovery was uneventful with no problems during the following 6 months. CONCLUSIONS: The proposed technique for a patient with complete SI and dextrocardia offers several advantages: no need to downsize the donor in comparison with the recipient; no need for cutdown of the liver; no risk of kinking of the venous outflow; hepatic hila are aligned; and it allows for a standard arterial and biliary reconstruction. We recommend this technique as a procedure of choice for patients with SI and an intact vena cava.

Correlation of preoperative factors, severity of disease, type of oxygenator and perfusion times with mortality and morbidity of coronary bypass.

Previous studies have related preoperative status and severity of disease to the outcome of coronary artery bypass surgery. Although increased perfusion and clamp times increase the risk of cardiac surgical procedures, the importance of these factors in relation to the patient's preoperative condition and the severity of disease has not previously been determined. In this study of 1078 patients, we examined the correlation between the patient's preoperative condition, the severity of coronary disease, and duration of perfusion and clamp time, and the type of oxygenator used with the mortality and morbidity associated with coronary artery bypass grafting. One-way analysis of variance and multiple correlation analysis showed that perfusion time, clamp time and nonclamp perfusion time correlated with mortality, perioperative infarction, the use of intra-aortic balloon pump, stroke, renal failure, pulmonary failure, infection, and leg wound complications (p less than 0.05). Perfusion time, clamp time and nonclamp perfusion time did not correlate with postoperative bleeding or sternal wound complications. Nonclamp perfusion time correlated more strongly than any other factor with mortality, perioperative infarction, the use of intra-aortic balloon pump, renal failure, pulmonary failure and infection (p less than 0.05). Clamp time correlated more than any other factor with the development of leg-wound complications (p less than 0.05). The use of a bubble rather than a membrane oxygenator was significantly related to mortality, stroke, infection and leg wound complications by one-way analysis of variance (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The wrist tourniquet: an alternative technique in hand surgery.

This study investigated the efficacy and safety of the use of a size 8 1/2 surgical glove as a wrist tourniquet in hand surgery. A neonatal blood pressure cuff was placed under the wrist tourniquet to measure the presssures generated with use of this technique. The wrist tourniquet was applied in 25 consecutive procedures. Pressures generated with this technique ranged from 110 mm Hg to 260 mm Hg, with a mean pressure of 158 mm Hg. The average tourniquet time was 29 minutes, with the longest time being 135 minutes. The tourniquet achieved a bloodless surgical field in 24 (96%) of the 25 patients, and was well tolerated in all but two patients. Aside from tourniquet pain in these two (8%) patients, and tourniquet failure in one (4%) patient, there were no other complications associated with the wrist tourniquet. The size 8 1/2 surgical glove can be adopted as an effective and safe tourniquet in hand surgery.

Correlates of preoperative hematocrit value in patients undergoing coronary artery bypass.

The patient's preoperative red cell volume and hematocrit value are among the strongest predictors of need for postoperative transfusion. We have determined the factors that correlate with preoperative hematocrit value. We performed multiple regression analysis with preoperative hematocrit value as the dependent variable. The factors that were significantly correlated with preoperative hematocrit value, in order of their decreasing contribution to variability, were sex, date of operation, preoperative hospital stay, weight, left ventricular end-diastolic pressure, age, smoking history, and recent myocardial infarction (less than 6 weeks). Factors that did not contribute significantly to predicting preoperative hematocrit value included ejection fraction, emergency operation, previous streptokinase use, number of coronary arteries diseased, body mass index (obesity), diabetes, height, body surface area, and history of percutaneous transluminal coronary angioplasty. The patient most likely to have a low preoperative hematocrit value can be characterized as a small, elderly, female nonsmoker with a recent myocardial infarction and elevated left ventricular end-diastolic pressure. The prevalence of low preoperative hematocrit value is increasing with time independent of other factors.

Preoperative correlates of impaired wound healing after saphenous vein excision.

Although major wound complications after saphenous vein excision are infrequent, we have found broadly defined impairment in leg wound healing to be relatively common. Wound healing impairment is defined in this study as inflammation, separation, cellulitis, lymphangitis, drainage, necrosis, or abscess necessitating dressing, antibiotics, or débridement before wound healing with complete epithelialization without eschar. Healing was impaired in 245 of 1047 patients (24.3%). Significant correlations were found between impaired wound healing and female sex (p less than 0.005), body mass index (obesity) (p less than 0.005), diabetes mellitus (p less than 0.005), left ventricular end-diastolic pressure greater than 15 mm Hg (p = 0.0074), arterial occlusive disease of the legs (p = 0.0124), and preoperative hematocrit value (p = 0.0491).

Rectus femoris myocutaneous flaps for trochanteric ulcers.

The local skin flaps traditionally used to repair trochanteric ulcers in paraplegics are usually thin, have poor padding qualities and often break down. The rectus femoris myocutaneous flap was used to repair trochanteric ulcers in eight paraplegic patients. Three flaps healed primarily. In three there was some necrosis at the distal corner of the flap but this healed spontaneously. The cutaneous portion of two flaps necrosed and had to be excised but the muscle remained viable. All eight flaps remain healed with no evidence of breakdown. The repetitive shear forces over the prominent mobile hip joint cause particular problems in providing a stable flap repair, but the rectus femoris myocutaneous flap has demonstrated, in this series, its stability and durability.

The rib-pectoralis major osteomyocutaneous flap.

We describe a reliable composite osteomyocutaneous flap used for mandibular reconstruction in 14 patients. The flap is composed of the pectoralis major muscle and the attached fifth or sixth rib, with the overlying skin. This flap is tunneled superiorly under the neck skin. The muscle protects the great vessels. The skin lines the oral cavity or fills an external skin defect, and the rib replaces lost mandible. The rib seems to be adequately vascularized to survive, and does not resorb. Boney union is painless and clinically firm. One flap in the series was lost, and the rib was removed in 3 others. There was 1 persistent fistula.

A new method of oral reconstruction using a free composite foot flap.

We present a series of 10 free composite foot flaps used in 9 patients for floor-of-mouth and mandible reconstruction after composite resection. This one-stage repair replaces the soft tissue as well as the bone that has been resected. The flap is easily obtained from the foot, and is tailored to meet the requirements of the mouth and jaw defect. Donor site morbidity is surprisingly low: two flaps were lost from vascular obstruction, and 1 from delayed infection at ten days. The surviving flaps have provided good cosmetic and functional results. Bony union has occurred in half the grafts, and satisfactory firm fibrous union in the remainder. The flap is also useful for late reconstruction in "oral cripples," and may be used with the skin internally or externally as required. We are pleased with the versatility of this flap in complicated reconstructions.